Articles de revues : « Amb a 1 »

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Ogoshi, Maho, Shigenori Nobata et Yoshio Takei. « Potent osmoregulatory actions of homologous adrenomedullins administered peripherally and centrally in eels ». American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 295, n^o 6 (décembre 2008) : R2075—R2083. http://dx.doi.org/10.1152/ajpregu.90688.2008.

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The teleost adrenomedullin (AM) family consists of three groups, AM1/AM4, AM2/AM3, and AM5. In the present study, we examined the effects of homologous AM1, AM2, and AM5 on drinking and renal function after peripheral or central administration in conscious freshwater eels. AM2 and AM5, but not AM1, exhibited dose-dependent (0.01–1 nmol/kg) dipsogenic and antidiuretic effects after intra-arterial bolus injection. The antidiuretic effect was significantly correlated with the degree of associated hypotension. To avoid the potential indirect osmoregulatory effects of AM-induced hypotension, infusion of AMs was also performed at nondepressor doses. Drinking was enhanced dose-dependently at 0.1–3 pmol·kg−1·min−1 of AM2 and AM5, matching the potency and efficacy of angiotensin II (ANG II), the most potent dipsogenic hormone known thus far. AM2 and AM5 infusion also induced mild antidiuresis, while AM1 caused antinatriuresis. Additionally, AMs were injected into the third and fourth ventricles of conscious eels to assess their site of dipsogenic action. However, none of the AMs at 0.05–0.5 nmol induced drinking, while ANG II was highly dipsogenic. AM2 and ANG II injected into the third ventricle increased arterial pressure while AM5 decreased it in a dose-dependent manner, and both AM2 and AM5 decreased blood pressure when injected into the fourth ventricle. These data suggest that circulating AM2 and AM5 act on a target site in the brain that lacks the blood-brain barrier. Collectively, the present study showed that AM2 and AM5 are potent osmoregulatory hormones in the eel, and their actions imply involvement in seawater adaptation of this euryhaline species.

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Oakley, Karen L., Caroline B. Moore et David W. Denning. « In Vitro Activity of the Echinocandin Antifungal Agent LY303,366 in Comparison with Itraconazole and Amphotericin B against Aspergillus spp ». Antimicrobial Agents and Chemotherapy 42, n^o 10 (1 octobre 1998) : 2726–30. http://dx.doi.org/10.1128/aac.42.10.2726.

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ABSTRACT LY303,366 (LY) is a novel derivative of the echinocandin class of antifungal agents. The in vitro activities of LY, itraconazole (ITZ), and amphotericin B (AMB) were assessed against 60Aspergillus isolates, including 35 isolates of A. fumigatus, eight isolates of A. terreus, eight isolates of A. flavus, eight isolates of A. niger and one isolate of A. nidulans. Four A. fumigatus isolates were resistant to ITZ. Susceptibility testing for all drugs was performed with a broth microdilution procedure. LY was tested in two media: antibiotic medium 3 (AM3) and Casitone with 2% glucose (CAS) with an inoculum of 2 × 103spores/ml. ITZ and AMB were tested in RPMI 1640 with 2% glucose with an inoculum of 1 × 106 spores/ml. All tests were incubated at 37°C for 48 h. A novel end point was used to determine a minimal effective concentration (MEC) for LY, i.e., almost complete inhibition of growth save a few tiny spherical colonies attached to the microplate. MICs were measured for ITZ and AMB with a no-growth end point. Ranges and geometric mean (GM) MECs were from 0.0018 to >0.5 and 0.0039 mg/liter and from 0.0018 to >0.5 and 0.008 mg/liter for LY in AM3 and LY in CAS, respectively. Differences between species were apparent, with A. flavus being significantly less susceptible to LY than any other species tested with both media (P ≤ 0.05). Ranges and GM MICs were from 0.125 to >16 and 0.7 mg/liter for ITZ and from 0.25 to 16 and 1.78 mg/liter for AMB. Minimal fungicidal concentrations (MFCs) were also determined for all drugs. GM MFCs were 0.018, 0.09, 19.76, and 12.64 mg/liter for LY in AM3, LY in CAS, ITZ, and AMB, respectively. LY in AM3 and LY in CAS were fungicidal for 86.7 and 68% of isolates, respectively (98% killing). In comparison, ITZ and AMB were fungicidal for 35 and 70% of isolates, respectively (99.99% killing). A reproducibility study was performed on 20% of the isolates. For 12 isolates retested, the MEC or MIC was the same or was within 1 dilution of the original value for 11, 11, 10, and 9 isolates for LY in AM3, LY in CAS, ITZ, and AMB, respectively. In conclusion, LY seems to be a promising antifungal agent with excellent in vitro activity against Aspergillusspp.

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Yeo, Eun-Jin, Ji-Hye Ryu, Young-Suk Cho, Yang-Sook Chun, L. Eric Huang, Myung-Suk Kim et Jong-Wan Park. « Amphotericin B blunts erythropoietin response to hypoxia by reinforcing FIH-mediated repression of HIF-1 ». Blood 107, n^o 3 (1 février 2006) : 916–23. http://dx.doi.org/10.1182/blood-2005-06-2564.

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AbstractAmphotericin B (AmB) is widely used for treating severe systemic fungal infections. However, long-term AmB treatment is invariably associated with adverse effects such as anemia. The erythropoietin (EPO) suppression by AmB has been proposed to contribute to the development of anemia. However, the mechanism whereby EPO is suppressed remains obscure. In this study, we investigated the possibility that AmB inhibits the transcription of the EPO gene by inactivating HIF-1, which is a known key transcription factor and regulator of EPO expression. EPO mRNA levels were markedly attenuated by AmB treatment both in rat kidneys and in Hep3B cells. AmB inactivated the transcriptional activity of HIF-1α, but did not affect the expression or localization of HIF-1 subunits. Moreover, AmB was found to specifically repress the C-terminal transactivation domain (CAD) of HIF-1α, and this repression by AmB required Asn803, a target site of the factor-inhibiting HIF-1 (FIH); moreover, this repressive effect was reversed by FIH inhibitors. Furthermore, AmB stimulated CAD-FIH interaction and inhibited the p300 recruitment by CAD. We propose that this mechanism underlies the unexplained anemia associated with AmB therapy.

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Montagna, Maria Teresa, Grazia Lovero, Caterina Coretti, Osvalda De Giglio, Domenico Martinelli, Andrea Bedini, Mario Delia, Antonio Rosato, Mauro Codeluppi et Giuseppina Caggiano. « In vitro activities of amphotericin B deoxycholate and liposomal amphotericin B against 604 clinical yeast isolates ». Journal of Medical Microbiology 63, n^o 12 (1 décembre 2014) : 1638–43. http://dx.doi.org/10.1099/jmm.0.075507-0.

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We determined the in vitro antifungal activity of liposomal amphotericin B (L-AmB) against 604 clinical yeast isolates. Amphotericin B deoxycholate (D-AmB) was tested in parallel against all the isolates. Susceptibility testing was performed according to the Clinical and Laboratory Standards Institute (CLSI) M27-A3 method. Overall, L-AmB was highly active against the isolates (mean MIC, 0.42 µg ml−1; MIC90, 1 µg ml−1; 97.2 % of MICs were ≤1 µg ml−1) and comparable to D-AmB (mean MIC, 0.48 µg ml−1; MIC90, 1 µg ml−1; 97.3 % of MICs were ≤1 µg ml−1). The in vitro activity of D-AmB and L-AmB was correlated (R 2 = 0.61; exp(b), 2.3; 95 % CI, 2.19–2.44, P<0.001). Candida albicans (mean MICs of D-AmB and L-AmB, 0.39 µg ml−1 and 0.31 µg ml−1, respectively) and Candida parapsilosis (mean MICs of D-AmB and L-AmB, 0.38 µg ml−1 and 0.35 µg ml−1, respectively) were the species most susceptible to the agents tested, while Candida krusei (currently named Issatchenkia orientalis) (mean MICs of D-AmB and L-AmB, 1.27 µg ml−1 and 1.13 µg ml−1, respectively) was the least susceptible. The excellent in vitro activity of L-AmB may have important implications for empirical treatment approaches and support its role in treatment of a wide range of invasive infections due to yeasts.

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Zbîrcea, Lauriana-Eunice, Maria-Roxana Buzan, Manuela Grijincu, Elijahu Babaev, Frank Stolz, Rudolf Valenta, Virgil Păunescu, Carmen Panaitescu et Kuan-Wei Chen. « Relationship between IgE Levels Specific for Ragweed Pollen Extract, Amb a 1 and Cross-Reactive Allergen Molecules ». International Journal of Molecular Sciences 24, n^o 4 (17 février 2023) : 4040. http://dx.doi.org/10.3390/ijms24044040.

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Ragweed (Ambrosia artemisiifolia) pollen is a major endemic allergen source responsible for severe allergic manifestations in IgE-sensitized allergic patients. It contains the major allergen Amb a 1 and cross-reactive allergen molecules, such as the cytoskeletal protein profilin, Amb a 8 and calcium-binding allergens Amb a 9 and Amb a 10. To assess the importance of Amb a 1, profilin and calcium-binding allergen, the IgE reactivity profiles of clinically well-characterized 150 ragweed pollen-allergic patients were analysed regarding specific IgE levels for Amb a 1 and cross-reactive allergen molecules by quantitative ImmunoCAP measurements, IgE ELISA and by basophil activation experiments. By quantifying allergen-specific IgE levels we found that Amb a 1-specific IgE levels accounted for more than 50% of ragweed pollen-specific IgE in the majority of ragweed pollen-allergic patients. However, approximately 20% of patients were sensitized to profilin and the calcium-binding allergens, Amb a 9 and Amb a 10, respectively. As shown by IgE inhibition experiments, Amb a 8 showed extensive cross-reactivity with profilins from birch (Bet v 2), timothy grass (Phl p 12) and mugwort pollen (Art v 4) and was identified as a highly allergenic molecule by basophil activation testing. Our study indicates that molecular diagnosis performed by the quantification of specific IgE to Amb a 1, Amb a 8, Amb a 9 and Amb a 10 is useful to diagnose genuine sensitization to ragweed pollen and to identify patients who are sensitized to highly cross-reactive allergen molecules present in pollen from unrelated plants, in order to enable precision medicine-based approaches for the treatment and prevention of pollen allergy in areas with complex pollen sensitization.

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Lobato-Freitas, Carolina, Andreia Machado Brito-da-Costa, Ricardo Jorge Dinis-Oliveira, Helena Carmo, Félix Carvalho, João Pedro Silva et Diana Dias-da-Silva. « Overview of Synthetic Cannabinoids ADB-FUBINACA and AMB-FUBINACA : Clinical, Analytical, and Forensic Implications ». Pharmaceuticals 14, n^o 3 (25 février 2021) : 186. http://dx.doi.org/10.3390/ph14030186.

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ADB-FUBINACA and AMB-FUBINACA are two synthetic indazole-derived cannabinoid receptor agonists, up to 140- and 85-fold more potent, respectively, than trans-∆9-tetrahydrocannabinol (∆9-THC), the main psychoactive compound of cannabis. Synthesised in 2009 as a pharmaceutical drug candidate, the recreational use of ADB-FUBINACA was first reported in 2013 in Japan, with fatal cases being described in 2015. ADB-FUBINACA is one of the most apprehended and consumed synthetic cannabinoid (SC), following AMB-FUBINACA, which emerged in 2014 as a drug of abuse and has since been responsible for several intoxication and death outbreaks. Here, we critically review the physicochemical properties, detection methods, prevalence, biological effects, pharmacodynamics and pharmacokinetics of both drugs. When smoked, these SCs produce almost immediate effects (about 10 to 15 s after use) that last up to 60 min. They are rapidly and extensively metabolised, being the O-demethylated metabolite of AMB-FUBINACA, 2-(1-(4-fluorobenzyl)-1H-indazole-3-carboxamide)-3-methylbutanoic acid, the main excreted in urine, while for ADB-FUBINACA the main biomarkers are the hydroxdimethylpropyl ADB-FUBINACA, hydroxydehydrodimethylpropyl ADB-FUBINACA and hydroxylindazole ADB-FUBINACA. ADB-FUBINACA and AMB-FUBINACA display full agonism of the CB1 receptor, this being responsible for their cardiovascular and neurological effects (e.g., altered perception, agitation, anxiety, paranoia, hallucinations, loss of consciousness and memory, chest pain, hypertension, tachycardia, seizures). This review highlights the urgent requirement for additional studies on the toxicokinetic properties of AMB-FUBINACA and ADB-FUBINACA, as this is imperative to improve the methods for detecting and quantifying these drugs and to determine the best exposure markers in the various biological matrices. Furthermore, it stresses the need for clinicians and pathologists involved in the management of these intoxications to describe their findings in the scientific literature, thus assisting in the risk assessment and treatment of the harmful effects of these drugs in future medical and forensic investigations.

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Chen, Tao, Lawrence Mwenge, Shabir Lakhi, Duncan Chanda, Peter Mwaba, Síle F. Molloy, Adrian Gheorghe et al. « Healthcare Costs and Life-years Gained From Treatments Within the Advancing Cryptococcal Meningitis Treatment for Africa (ACTA) Trial on Cryptococcal Meningitis : A Comparison of Antifungal Induction Strategies in Sub-Saharan Africa ». Clinical Infectious Diseases 69, n^o 4 (13 mars 2019) : 588–95. http://dx.doi.org/10.1093/cid/ciy971.

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Abstract Background Mortality from cryptoccocal meningitis remains high. The ACTA trial demonstrated that, compared with 2 weeks of amphotericin B (AmB) plus flucystosine (5FC), 1 week of AmB and 5FC was associated with lower mortality and 2 weeks of oral flucanozole (FLU) plus 5FC was non-inferior. Here, we assess the cost-effectiveness of these different treatment courses. Methods Participants were randomized in a ratio of 2:1:1:1:1 to 2 weeks of oral 5FC and FLU, 1 week of AmB and FLU, 1 week of AmB and 5FC, 2 weeks of AmB and FLU, or 2 weeks of AmB and 5FC in Malawi, Zambia, Cameroon, and Tanzania. Data on individual resource use and health outcomes were collected. Cost-effectiveness was measured as incremental costs per life-year saved, and non-parametric bootstrapping was done. Results Total costs per patient were US $1442 for 2 weeks of oral FLU and 5FC, $1763 for 1 week of AmB and FLU, $1861 for 1 week of AmB and 5FC, $2125 for 2 weeks of AmB and FLU, and $2285 for 2 weeks of AmB and 5FC. Compared to 2 weeks of AmB and 5FC, 1 week of AmB and 5FC was less costly and more effective and 2 weeks of oral FLU and 5FC was less costly and as effective. The incremental cost-effectiveness ratio for 1 week of AmB and 5FC versus oral FLU and 5FC was US $208 (95% confidence interval $91–1210) per life-year saved. Clinical Trials Registration ISRCTN45035509. Conclusions Both 1 week of AmB and 5FC and 2 weeks of Oral FLU and 5FC are cost-effective treatments.

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Nath, Christa E., Peter J. Shaw, Robyn Gunning, Andrew J. McLachlan et John W. Earl. « Amphotericin B in Children with Malignant Disease : a Comparison of the Toxicities and Pharmacokinetics of Amphotericin B Administered in Dextrose versus Lipid Emulsion ». Antimicrobial Agents and Chemotherapy 43, n^o 6 (1 juin 1999) : 1417–23. http://dx.doi.org/10.1128/aac.43.6.1417.

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ABSTRACT In a prospective, randomized clinical trial, the toxicity of 1 mg of amphotericin B (AmB) per kg of body weight per day infused in 5% dextrose was compared with that of AmB infused in lipid emulsion in children with malignant disease. In an analysis of 82 children who received a full course of 6 days or more of AmB (117 courses), it was shown that there were significant increases in plasma urea and creatinine concentrations and in potassium requirement after 6 days of therapy with both AmB infused in dextrose and AmB infused in lipid emulsion, with there being no difference between the two methods of AmB administration. An intent-to-treat comparison of the numbers of courses affected by acute toxicity (fever, rigors) and chronic toxicity (nephrotoxicity) also indicated that there was no significant difference between AmB infused in dextrose (78 courses) and AmB infused in lipid emulsion (84 courses). The pharmacokinetics of AmB were investigated in 20 children who received AmB in dextrose and 15 children who received AmB in lipid emulsion. Blood samples were collected up to 24 h after administration of the first dose, and the concentration of AmB in plasma was analyzed by a high-performance liquid chromatography assay. The clearance (CL) of AmB in dextrose (0.039 ± 0.016 liter · h−1 · kg−1) was significantly lower (P < 0.005) than the CL of AmB in lipid emulsion (0.062 ± 0.024 liter · h−1 · kg−1). The steady-state volume of distribution for AmB in dextrose (0.83 ± 0.33 liter · kg−1) was also significantly lower (P < 0.005) than that for AmB in lipid emulsion (1.47 ± 0.77 liter · kg−1). Although AmB in lipid emulsion is apparently cleared faster and distributes more widely than AmB in dextrose, this study did not reveal any significant advantage with respect to safety and tolerance in the administration of AmB in lipid emulsion compared to its administration in dextrose in children with malignant disease.

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Alakkad, Abdulghani, Paul Stapleton, Corinna Schlosser, Sudaxshina Murdan, Uchechukwu Odunze, Andreas Schatzlein et Ijeoma F. Uchegbu. « Amphotericin B Polymer Nanoparticles Show Efficacy against Candida Species Biofilms ». Pathogens 11, n^o 1 (7 janvier 2022) : 73. http://dx.doi.org/10.3390/pathogens11010073.

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Purpose: Chronic infections of Candida albicans are characterised by the embedding of budding and entwined filamentous fungal cells into biofilms. The biofilms are refractory to many drugs and Candida biofilms are associated with ocular fungal infections. The objective was to test the activity of nanoparticulate amphotericin B (AmB) against Candida biofilms. Methods: AmB was encapsulated in the Molecular Envelope Technology (MET, N-palmitoyl-N-monomethyl-N,N-dimethyl-N,N,N-trimethyl-6-O-glycolchitosan) nanoparticles and tested against Candida biofilms in vitro. Confocal laser scanning microscopy (CLSM) imaging of MET nanoparticles’ penetration into experimental biofilms was carried out and a MET-AmB eye drop formulation was tested for its stability. Results: MET-AmB formulations demonstrated superior activity towards C. albicans biofilms in vitro with the EC50 being ~30 times lower than AmB alone (EC50 MET-AmB = 1.176 μg mL−1, EC50 AmB alone = 29.09 μg mL−1). A similar superior activity was found for Candida glabrata biofilms, where the EC50 was ~10× lower than AmB alone (EC50 MET-AmB = 0.0253 μg mL−1, EC50 AmB alone = 0.289 μg mL−1). CLSM imaging revealed that MET nanoparticles penetrated through the C. albicans biofilm matrix and bound to fungal cells. The activity of MET-AmB was no different from the activity of AmB alone against C. albicans cells in suspension (MET-AmB MIC90 = 0.125 μg mL−1, AmB alone MIC90 = 0.250 μg mL−1). MET-AmB eye drops were stable at room temperature for at least 28 days. Conclusions: These biofilm activity findings raise the possibility that MET-loaded nanoparticles may be used to tackle Candida biofilm infections, such as refractory ocular fungal infections.

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Florenza Satorres, Patrícia. « Actors, mims i altres pallassades. 3, 2, 1, acció ! » Comunicació educativa, n^o 30 (24 mars 2020) : 61. http://dx.doi.org/10.17345/comeduc201761-76.

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Des de fa uns anys, a l’Escola Guillem Fortuny de Cambrils duem a terme una experiència expressiva, vivencial i creativa en què, mitjançant l’experimentació dels diferents recursos expressius i el treball del llenguatge corporal, els alumnes fan representacions amb mímica en grups cooperatius.L’expressió corporal potencia el desenvolupament natural de les expressions i manifestacions corporals de l’infant, amb la idea que sigui ell mateix i que el joc amb el cos li serveixi per conèixer-se i aprendre a comunicar-se sense contradiccions que l’inhibeixin.

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Cordonnier, Catherine, Thomas J. Walsh et Mark Bresnik. « Liposomal Amphotericin B (L-AMB) Is Superior to Amphotericin B Deoxycholate (AmB-d) in Preventing Breakthrough Fungal Infections in Patients with Prolonged Neutropenia and Fever : Results of a Sub-Group Analysis of an Empirical Antifungal Therapy Trial. » Blood 104, n^o 11 (16 novembre 2004) : 1336. http://dx.doi.org/10.1182/blood.v104.11.1336.1336.

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Abstract In a trial of empirical antifungal therapy in persistently febrile neutropenic patients, L-AMB was shown to be comparable in overall efficacy with significantly less nephrotoxicity and infusion-related reactions when compared to AmB-d. In addition, significantly fewer proven breakthrough invasive fungal infections (IFI) occurred in the L-AMB treatment group. (Walsh TJ, et al, NEJM1999; 340: 764–71). In order to better evaluate the maximum efficacy benefit of L-AMB in a higher risk patient subset, a sub-group analysis was performed on those patients with duration of neutropenia greater than or equal to the median duration for the entire study population. The results of this sub-group analysis are presented. Methods: From the original data set, the median duration of neutropenia from the time of treatment initiation was determined. Clinical success (defined by a composite endpoint), frequency of proven breakthrough IFI and all cause mortality were reported by treatment group for patients with duration of neutropenia greater than or equal to the median. Investigator-reported proven breakthrough IFI were reviewed and verified by an independent, blinded expert. Results: A total of 687 patients were enrolled in the trial. Median duration of neutropenia following initiation of antifungal therapy was 7 days (range 1–50). 392 patients had neutropenia >/= 7 days, (L-AMB=205), (AmB-d=187). Clinical success: L-AMB: 128/205 (62.4%); AmB-d: 112/187 (59.9%), and all cause mortality: L-AMB: 19/205 (9.3%); AmB-d: 24/187 (12.8%) were not significantly different. The frequency of proven breakthrough IFI favored L-AMB: L-AMB: 7/205 (3.4%); AmB-d: 18/187 (9.6%), p=0.01. Organisms isolated: L-AMB: 2 Candida spp (blood); 4 Aspergillus spp. (3 pneumonia, 1 wound); 1 Mucor sp (pneumonia). AmB-d: 9 Candida spp (8 blood, 1 pneumonia); 7 Aspergillus spp (4 pneumonia, 1 sinus, 1 pericarditis, 1 wound); 1 Cryptococcus albidus (blood); 1 unclassified mould (pneumonia). The difference in emergent proven IFI for the patients with neutropenia <7d trended in favor of L-AMB, but was not statistically significant: L-AMB 3/138 (2.2%); AmB-d 8/157 (5.1%). Conclusions: Overall clinical success and all cause mortality remained equivalent for the 2 treatment arms in the subset of patients with prolonged neutropenia. However, L-AMB significantly reduced the frequency of proven breakthrough IFI in this high-risk patient population. These data support the efficacy of L-AMB as empirical therapy, particularly for persistently neutropenic patients at higher risk for invasive fungal infections.

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Ciriello, John, et Cleusa V. R. de Oliveira. « Cardiac effects of hypocretin-1 in nucleus ambiguus ». American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 284, n^o 6 (1 juin 2003) : R1611—R1620. http://dx.doi.org/10.1152/ajpregu.00719.2002.

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Although recent studies have reported hypocretin 1 (hcrt-1)-like-immunoreactivity (ir) within the region of the nucleus ambiguus (Amb) in the caudal brain stem, the function of hcrt-1 in the Amb on cardiovascular function is not known. Three series of experiments were done in male Wistar rats to investigate the effects of microinjections of hcrt-1 into Amb on heart rate (HR), mean arterial pressure (MAP), and the arterial baroreceptor reflex. In the first series, a detailed mapping of the distribution of hcrt-1- and hcrt-1 receptor (hcrtR-1)-like-ir was obtained of the Amb region. Although hcrt-1-like- and hcrtR-1-like-ir were found throughout the rostrocaudal extent of the Amb and adjacent ventrolateral medullary reticular formation, most of the hcrtR-1-like-ir was observed in the area just ventral to the compact formation of Amb, in the region of the external formation of the nucleus (Ambe). In the second series, the Amb region that contained hcrt-1 and hcrtR-1-ir was explored for sites that elicited changes in HR and MAP in urethane and α-chloralose-anesthetized rats. Microinjections of hcrt-1 (0.5–2.5 pmol) into the Ambe elicited a dose-related decrease in HR, with little or no direct change in MAP. The small decreases in MAP were found to be secondary to the HR changes. The largest bradycardia responses were elicited from sites in the Ambe. Administration (iv) of the muscarinic receptor antagonist atropine methyl bromide or ipsilateral vagotomy abolished the HR response, indicating that the HR response was due to activation of vagal cardiomotor neurons. In the final series, microinjections of hcrt-1 into the Ambe significantly potentiated the reflex bradycardia elicited by activation of the baroreflex as a result of the increased MAP after the intravenous injection of phenylephrine. These data suggest that hcrt-1 in the Ambe activates neuronal systems that alter the excitability of central circuits that reflexly control the circulation through the activation of vagal preganglionic cardioinhibitory neurons.

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Bond, J. F., R. D. Garman, K. M. Keating, T. J. Briner, T. Rafnar, D. G. Klapper et B. L. Rogers. « Multiple Amb a I allergens demonstrate specific reactivity with IgE and T cells from ragweed-allergic patients. » Journal of Immunology 146, n^o 10 (15 mai 1991) : 3380–85. http://dx.doi.org/10.4049/jimmunol.146.10.3380.

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Abstract The relationship between the structure and abundance of an inhaled protein and its potential for causing an allergic response is unknown. This study analyzes Amb a I, a family of related proteins formerly known as Ag E, that comprise the major allergens of short ragweed (Ambrosia artemisiifolia). T cells isolated from ragweed allergic patients were shown to proliferate in response to purified Amb a I.1 protein from pollen in in vitro secondary cultures, demonstrating the presence of T cell stimulatory epitopes in Amb a I.1. Three recombinant forms of Amb a I (Amb a I.1, Amb a I.2, and Amb a I.3) obtained as cDNA derived from pollen mRNA were expressed in bacteria. All three recombinant forms were shown to be specifically recognized by pooled ragweed-allergic human IgE on immunoblots, confirming these gene products are important allergens. An examination of immunoblots probed with sera derived from allergic patients revealed a variation in IgE binding specificity. A minority of patients' IgE exclusively reacted with recombinant Amb a I.1, whereas most patients' IgE reacted with Amb a I.1 as well as Amb a I.2 and Amb a I.3 proteins. A detailed examination of the reactivity of T cells derived from 12 allergic patients to these recombinant Amb a I forms revealed that these allergens are all capable of stimulating T cell proliferation in in vitro assays. It is concluded that the allergic response to ragweed pollen in most allergic patients is composed of a reaction to multiple related Amb a I proteins at both the B and T cell levels.

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Bezerra, Gabriela Freire, Gdayllon Cavalcante Meneses, Vittória Nobre Jacinto, Danya Bandeira Lima, Emanuel Paula Magalhães, Lana Andrade Lucena Lima, Thaiany Pereira da Rocha et al. « Preliminary Study for New Markers of Early Tubuloglomerular Injury and Renal Inflammation in Patients with Visceral Leishmaniasis Receiving Liposomal Amphotericin B Treatment ». American Journal of Tropical Medicine and Hygiene 106, n^o 4 (6 avril 2022) : 1191–95. http://dx.doi.org/10.4269/ajtmh.21-0978.

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ABSTRACT. Visceral leishmaniasis is treated with liposomal amphotericin B (L-AMB), which is associated with nephrotoxicity. Thus, we aimed to investigate nephrotoxicity through novel renal biomarkers in patients with visceral leishmaniasis during L-AMB use. Ours was a prospective study with 17 patients with visceral leishmaniasis treated with L-AMB during their hospital stay. Laboratory tests, renal parameters, urinary biomarkers (urinary kidney injury molecule 1, urinary monocyte chemoattractant protein 1 [uMCP-1], sodium–potassium–2 chloride cotransporter [NKCC2], sodium–hydrogen exchanger 3) [NHE3], aquaporin 2 [AQP2], tumor susceptibility gene 101 [TSH 101], and serum inflammatory biomarkers (MCP-1, interferon-γ, and IL-6) were evaluated in two periods: before and during L-AMB use. Glomerular filtration rate, creatinine, proteinuria, and albuminuria were similar before and during L-AMB use. IL-6 levels, AQT2, and NHE3 expression decreased, whereas uMCP-1 and urinary kidney injury molecule 1 levels increased during L-AMB treatment. In patients who developed acute kidney injury, uMCP-1 showed higher levels. L-AMB aggravated tubuloglomerular lesions, inflammation, and renal tubular disorders. Thus, patients treated with L-AMB need to be monitored for inflammatory and electrolyte disturbances to prevent acute kidney injury, longer length of hospital stay, higher public costs, and mortality.

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Groll, Andreas H., Diana Mickiene, Stephen C. Piscitelli et Thomas J. Walsh. « Distribution of Lipid Formulations of Amphotericin B into Bone Marrow and Fat Tissue in Rabbits ». Antimicrobial Agents and Chemotherapy 44, n^o 2 (1 février 2000) : 408–10. http://dx.doi.org/10.1128/aac.44.2.408-410.2000.

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ABSTRACT The distribution of the three currently available lipid formulations of amphotericin B (AmB) into bone marrow and fat tissue was evaluated in noninfected rabbits. Groups of four animals each received either 1 mg of AmB deoxycholate (D-AmB) per kg of body weight per day or 5 mg of AmB colloidal dispersion, AmB lipid complex, or liposomal AmB per kg per day for seven doses. Plasma, bone marrow, fat, and liver were collected at autopsy, and AmB concentrations were determined by high-performance liquid chromatography. At the investigated dosages of 5 mg/kg/day, all AmB lipid formulations achieved at least fourfold-higher concentrations in bone marrow than did standard D-AmB at a dosage of 1 mg/kg/day. Concentrations in bone marrow were 62 to 76% of concurrent AmB concentrations in the liver. In contrast, all AmB formulations accumulated comparatively poorly in fat tissue. The results of this study show that high concentrations of AmB can be achieved in the bone marrow after administration of lipid formulations, suggesting their particular usefulness against disseminated fungal infections involving the bone marrow and against visceral leishmaniasis.

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Bekersky, Ihor, Robert M. Fielding, Dawna E. Dressler, Jean W. Lee, Donald N. Buell et Thomas J. Walsh. « Pharmacokinetics, Excretion, and Mass Balance of Liposomal Amphotericin B (AmBisome) and Amphotericin B Deoxycholate in Humans ». Antimicrobial Agents and Chemotherapy 46, n^o 3 (mars 2002) : 828–33. http://dx.doi.org/10.1128/aac.46.3.828-833.2002.

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ABSTRACT The pharmacokinetics, excretion, and mass balance of liposomal amphotericin B (AmBisome) (liposomal AMB) and the conventional formulation, AMB deoxycholate (AMB-DOC), were compared in a phase IV, open-label, parallel study in healthy volunteers. After a single 2-h infusion of 2 mg of liposomal AMB/kg of body weight or 0.6 mg of AMB-DOC/kg, plasma, urine, and feces were collected for 168 h. The concentrations of AMB were determined by liquid chromatography tandem mass spectrometry (plasma, urine, feces) or high-performance liquid chromatography (HPLC) (plasma). Infusion-related side effects similar to those reported in patients, including nausea and back pain, were observed in both groups. Both formulations had triphasic plasma profiles with long terminal half-lives (liposomal AMB, 152 ± 116 h; AMB-DOC, 127 ± 30 h), but plasma concentrations were higher (P < 0.01) after administration of liposomal AMB (maximum concentration of drug in serum [C max], 22.9 ± 10 μg/ml) than those of AMB-DOC (C max, 1.4 ± 0.2 μg/ml). Liposomal AMB had a central compartment volume close to that of plasma (50 ± 19 ml/kg) and a volume of distribution at steady state (V ss) (774 ± 550 ml/kg) smaller than the V ss of AMB-DOC (1,807 ± 239 ml/kg) (P < 0.01). Total clearances were similar (approximately 10 ml hr−1 kg−1), but renal and fecal clearances of liposomal AMB were 10-fold lower than those of AMB-DOC (P < 0.01). Two-thirds of the AMB-DOC was excreted unchanged in the urine (20.6%) and feces (42.5%) with >90% accounted for in mass balance calculations at 1 week, suggesting that metabolism plays at most a minor role in AMB elimination. In contrast, <10% of the liposomal AMB was excreted unchanged. No metabolites were observed by HPLC or mass spectrometry. In comparison to AMB-DOC, liposomal AMB produced higher plasma exposures and lower volumes of distribution and markedly decreased the excretion of unchanged drug in urine and feces. Thus, liposomal AMB significantly alters the excretion and mass balance of AMB. The ability of liposomes to sequester drugs in circulating liposomes and within deep tissue compartments may account for these differences.

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Bekersky, Ihor, Robert M. Fielding, Dawna E. Dressler, Jean W. Lee, Donald N. Buell et Thomas J. Walsh. « Plasma Protein Binding of Amphotericin B and Pharmacokinetics of Bound versus Unbound Amphotericin B after Administration of Intravenous Liposomal Amphotericin B (AmBisome) and Amphotericin B Deoxycholate ». Antimicrobial Agents and Chemotherapy 46, n^o 3 (mars 2002) : 834–40. http://dx.doi.org/10.1128/aac.46.3.834-840.2002.

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ABSTRACT Unilamellar liposomal amphotericin B (AmBisome) (liposomal AMB) reduces the toxicity of this antifungal drug. The unique composition of liposomal AMB stabilizes the liposomes, producing higher sustained drug levels in plasma and reducing renal and hepatic excretion. When liposomes release their drug payload, unbound, protein-bound, and liposomal drug pools may exist simultaneously in the body. To determine the amounts of drug in these pools, we developed a procedure to measure unbound AMB in human plasma by ultrafiltration and then used it to characterize AMB binding in vitro and to assess the pharmacokinetics of nonliposomal pools of AMB in a phase IV study of liposomal AMB and AMB deoxycholate in healthy subjects. We confirmed that AMB is highly bound (>95%) in human plasma and showed that both human serum albumin and α1-acid glycoprotein contribute to this binding. AMB binding exhibited an unusual concentration dependence in plasma: the percentage of bound drug increased as the AMB concentration increased. This was attributed to the low solubility of AMB in plasma, which limits the unbound drug concentration to <1 μg/ml. Subjects given 2 mg of liposomal AMB/kg of body weight had lower exposures (as measured by the maximum concentration of drug in serum and the area under the concentration-time curve) to both unbound and nonliposomal drug than those receiving 0.6 mg of AMB deoxycholate/kg. Most of the AMB in plasma remained liposome associated (97% at 4 h, 55% at 168 h) after liposomal AMB administration, so that unbound drug concentrations remained at <25 ng/ml in all liposomal AMB-treated subjects. Although liposomal AMB markedly reduces the total urinary and fecal recoveries of AMB, urinary and fecal clearances based on unbound AMB were similar (94 to 121 ml h−1 kg−1) for both formulations. Unbound drug urinary clearances were equal to the glomerular filtration rate, and tubular transit rates were <16% of the urinary excretion rate, suggesting that net filtration of unbound drug, with little secretion or reabsorption, is the mechanism of renal clearance for both conventional and liposomal AMB in humans. Unbound drug fecal clearances were also similar for the two formulations. Thus, liposomal AMB increases total AMB concentrations while decreasing unbound AMB concentrations in plasma as a result of sequestration of the drug in long-circulating liposomes.

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Campos, Evanil Pires de, Valquíria Oliveira Carvalho, Sonia Fontes Marinho, Tuba Milstein Kushnaroff, Paulo Augusto Ayrosa Galvão et Carlos Roberto Padovani. « Estudo retrospectivo terapêutico da neurocriptococose em 112 aidéticos ou não ». Revista da Sociedade Brasileira de Medicina Tropical 25, n^o 4 (décembre 1992) : 241–46. http://dx.doi.org/10.1590/s0037-86821992000400005.

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Cento e doze aidéticos ou não com neurocriptococose, admitidos no Hospital Emílio Ribas - São Paulo, Brasil, receberam anfotericina B (AMB) - grupo III ou a associação AMB/ 5 fluorcitosina (5FC): grupos I e II. Testes de Goodman aplicados revelaram: 1. leuco e glicorraquia semelhantes nos três grupos eproteinorraquia inferior a 85mg/dlapós 1, 5g/AMB; 1. a coloração pelo método da tinta da China e a cultura para Cryptococcus neoformans, positivas até l,Og/AMB; 3. hipocalemia na monoterapia, hipo e hipercalemia durante a associação; 4. as reações adversas mais evidentes a > 0,7gAMB/250g 5FC; 5. óbitos (precoce e tardio) frequentes no grupo 1 e nos grupos I e III entre 2,5 a 4,0g de AMB; 6. remissão e morte semelhantes nos grupos. A associação terapêutica iniciale amanutençãopelo AMB conduziram à recaída tardia

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Choudhury, Quanita J., Suresh Ambati, Zachary A. Lewis et Richard B. Meagher. « Targeted Delivery of Antifungal Liposomes to Rhizopus delemar ». Journal of Fungi 8, n^o 4 (30 mars 2022) : 352. http://dx.doi.org/10.3390/jof8040352.

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Mucormycosis (a.k.a. zygomycosis) is an often-life-threatening disease caused by fungi from the ancient fungal division Mucoromycota. Globally, there are nearly a million people with the disease. Rhizopus spp., and R. delemar (R. oryzae, R. arrhizus) in particular, are responsible for most of the diagnosed cases. Pulmonary, rhino-orbito-cerebral, and invasive mucormycosis are most effectively treated with amphotericin B (AmB) and particularly with liposomal formulations (e.g., AmBisome®). However, even after antifungal therapy, there is still a 50% mortality rate. Hence, there is a critical need to improve therapeutics for mucormycosis. Targeting AmB-loaded liposomes (AmB-LLs) with the pathogen receptor Dectin-1 (DEC1-AmB-LLs) to the beta-glucans expressed on the surface of Aspergillus fumigatus and Candida albicans lowers the effective dose required to kill cells relative to untargeted AmB-LLs. Because Dectin-1 is an immune receptor for R. delemar infections and may bind it directly, we explored the Dectin-1-mediated delivery of liposomal AmB to R. delemar. DEC1-AmB-LLs bound 100- to 1000-fold more efficiently to the exopolysaccharide matrix of R. delemar germlings and mature hyphae relative to AmB-LLs. DEC1-AmB-LLs delivering sub-micromolar concentrations of AmB were an order of magnitude more efficient at inhibiting and/or killing R. delemar than AmB-LLs. Targeted antifungal drug-loaded liposomes have the potential to improve the treatment of mucormycosis.

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Stergiopoulou, Theodouli, Joseph Meletiadis, Tin Sein, Paraskevi Papaioannidou, Thomas J. Walsh et Emmanuel Roilides. « Synergistic Interaction of the Triple Combination of Amphotericin B, Ciprofloxacin, and Polymorphonuclear Neutrophils against Aspergillus fumigatus ». Antimicrobial Agents and Chemotherapy 55, n^o 12 (12 septembre 2011) : 5923–29. http://dx.doi.org/10.1128/aac.00548-11.

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ABSTRACTAspergillusis damaged by polymorphonuclear neutrophils (PMNs) by means of nonoxidative and oxidative mechanisms, which may be affected by antifungal and antibacterial agents that patients with invasive pulmonary aspergillosis often receive. The pharmacodynamic interactions among deoxycholate amphotericin B (AMB), ciprofloxacin (CIP), and human PMNs againstAspergillus fumigatusgrowth are unknown. We therefore studied the interactions between 0.032 to 2.0 μg/ml of AMB, 0.1 to 50 μg/ml of CIP at a fixed AMB/CIP ratio of 1:3.125, and PMNs from six donors at an effector-to-target (E:T) ratio of 400:1 against a clinicalA. fumigatusisolate using an XTT metabolic assay and the Bliss independence pharmacodynamic-interaction model. CIP exhibited no antifungal activity alone or in combination with PMNs. Synergy was found between AMB and PMNs, with interaction indices (II) of 0.06 to 0.21; the highest interaction of 21% ± 3.6% was observed at 0.22 ± 0.09 μg/ml of AMB. The AMB and CIP (AMB+CIP) combination was synergistic (II = 0.39) at low AMB concentrations and antagonistic (II = 1.39) at high AMB concentrations, with a maximal synergistic interaction of 16% ± 3.7% observed at 0.16 ± 0.08 μg/ml of AMB. The triple combination AMB+CIP+PMNs was synergistic, with interaction indices of 0.05 to 0.20, and a maximal synergistic interaction of 24% ± 4% was observed at 0.20 ± 0.07 μg/ml of AMB. The increased percentage of Bliss synergy of the triple combination AMB+CIP+PMNs (24% ± 4%) was the product of those of the constituent double combinations AMB+PMNs (21% ± 3.6%) and AMB+CIP (16% ± 3.7%). Thus, the antifungal activity of AMB, at clinically relevant concentrations, was enhanced in combination with PMNs and CIP againstA. fumigatusgrowth in a concentration-dependent manner.

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Mohamed-Ahmed, Abeer H. A., Karin Seifert, Vanessa Yardley, Hollie Burrell-Saward, Stephen Brocchini et Simon L. Croft. « Antileishmanial Activity, Uptake, and Biodistribution of an Amphotericin B and Poly(α-Glutamic Acid) Complex ». Antimicrobial Agents and Chemotherapy 57, n^o 10 (24 juin 2013) : 4608–14. http://dx.doi.org/10.1128/aac.02343-12.

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ABSTRACTA noncovalent, water-soluble complex of amphotericin B (AMB) and poly(α-glutamic acid) (PGA), with AMB loadings ranging from 25 to 55% (wt/wt) using PGA with a molecular weight range of 50,000 to 70,000, was prepared as a potential new treatment for visceral leishmaniasis (VL). The AMB-PGA complex was shown to be as active as Fungizone (AMB deoxycholate) against intracellularLeishmania donovaniamastigotes in differentiated THP-1 cells. Thein vitrouptake of the AMB-PGA complex by differentiated THP-1 cells was similar to that of Fungizone and higher than that of AmBisome (liposomal AMB). The AMB-PGA complex also displayed a dose-response profile similar to that of AmBisomein vivoin BALB/c mice againstL. donovani, with 50% effective doses (ED50s) of 0.24 ± 0.03 mg/kg of body weight for the AMB-PGA complex and 0.24 ± 0.06 mg/kg for AmBisome. A biodistribution study with mice indicated that the AMB-PGA complex cleared more rapidly from plasma than AmBisome, with a comparable low level of distribution to the kidneys.

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Araújo, Ivonete Batista, C. Ramon N. Brito, Isabel A. Urbano, Victor A. Dominici, Miguel A. Silva Filho, Walteçá L. L. Silveira, Bolívar P. G. L. Damasceno, Aldo Cunha Medeiros et E. Sócrates T. Egito. « Similarity between the in vitro activity and toxicity of two different fungizone™ / lipofundin™ admixtures ». Acta Cirurgica Brasileira 20, suppl 1 (2005) : 129–33. http://dx.doi.org/10.1590/s0102-86502005000700022.

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PURPOSE: Amphotericin B (AmB), an antifungal agent that presents a broad spectrum of activity, remains the gold standard in the antifungal therapy. However, sometimes the high level of toxicity forbids its clinical use. The aim of this work was to evaluate and compare the efficacy and toxicity in vitro of Fungizon™ (AmB-D) and two new different AmB formulations. METHODS: three products were studied: Fungizon™, and two Fungizon™ /Lipofundin™ admixtures, which were diluted through two methods: in the first one, Fungizon™ was previously diluted with water for injection and then, in Lipofundin™ (AmB-DAL); the second method consisted of a primary dilution of AmB-D as a powder in the referred emulsion (AmB-DL). For the in vitro assay, two cell models were used: Red Blood Cells (RBC) from human donors and Candida tropicallis (Ct). The in vitro evaluation (K+ leakage, hemoglobin leakage and cell survival rate-CSR) was performed at four AmB concentrations (from 50 to 0.05mg.L-1). RESULTS: The results showed that the action of AmB was not only concentration dependent, but also cellular type and vehicle kind dependent. At AmB concentrations of 50 mg.L-1, although the hemoglobin leakage for AmB-D was almost complete (99.51), for AmB-DAL and AmB-DL this value tended to zero. The p = 0.000 showed that AmB-D was significantly more hemolytic. CONCLUSION: The Fungizon™-Lipofundin™ admixtures seem to be the more valuable AmB carrier systems due to their best therapeutic index presented.

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Papp, Zoltán, Andrew M. Borman, Lajos Forgács, Renátó Kovács, Zoltán Tóth, Chiu Chun-Ju, Gábor Kardos, Béla Juhász, Judit Szilvássy et László Majoros. « Unpredictable In Vitro Killing Activity of Amphotericin B against Four Candida auris Clades ». Pathogens 10, n^o 8 (6 août 2021) : 990. http://dx.doi.org/10.3390/pathogens10080990.

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Candida auris is an emerging multiresistant yeast against which amphotericin B (AMB) is still the first therapeutic choice in certain clinical situations (i.e., meningitis, endophthalmitis, and urinary tract infections). As data about the in vitro killing activity of AMB against C. auris clades are lacking, we determined MICs, minimum fungicidal concentrations (MFCs), and killing activity of AMB against 22 isolates representing the 4 major C. auris clades (South Asian n = 6; East Asian n = 4; South African n = 6, and South American n = 6). MIC values were ≤1 mg/L regardless of clades; MFC ranges were, 1–4 mg/L, 2–4 mg/L, 2 mg/L, and 2–8 mg/L for South Asian, East Asian, South African, and South American clades, respectively. AMB showed concentration-, clade-, and isolate-dependent killing activity. AMB was fungicidal at 1 mg/L against two of six, two of four, three of six, and one of six isolates from the South Asian, East Asian, South African, and South American clades, respectively. Widefield fluorescence microscopy showed cell number decreases at 1 mg/L AMB in cases of the South Asian, East Asian, and South African clades. These data draw attention to the weak killing activity of AMB against C. auris regardless of clades, even when MICs are low (≤1 mg/L). Thus, AMB efficacy is unpredictable in treatment of invasive C. auris infections.

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Rogers, B. L., J. P. Morgenstern, I. J. Griffith, X. B. Yu, C. M. Counsell, A. W. Brauer, T. P. King, R. D. Garman et M. C. Kuo. « Complete sequence of the allergen Amb alpha II. Recombinant expression and reactivity with T cells from ragweed allergic patients. » Journal of Immunology 147, n^o 8 (15 octobre 1991) : 2547–52. http://dx.doi.org/10.4049/jimmunol.147.8.2547.

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Abstract This study defines the complete primary structure of Amb alpha II, an important allergen produced by short ragweed (Ambrosia artemisiifolia). The deduced amino acid sequence derived from the cDNA indicates that Amb alpha II shares approximately 65% sequence identity with the Amb alpha I multigene family of allergens. Full-length cDNA encoding Amb alpha I.1 and Amb alpha II have been expressed in E. coli and purified. An in-frame linker encoding polyhistidine has been added to the 5' end of the cDNA to facilitate purification using Ni2+ ion affinity chromatography, yielding greater than 90% pure recombinant protein in a single step. T cells from patients allergic to ragweed proliferate in response to pollen extract as well as purified recombinant Amb alpha I.1 and Amb alpha II. T cell lines established using either Amb alpha I.1 or II as the stimulating Ag exhibit a high level of cross-reactivity to both proteins. This result is entirely consistent with the extensive primary sequence identity shared by these two proteins. These data suggest that allergic humans recognize shared T cell epitopes on these two related molecules.

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Razonable, Raymund R., Martin Henault, Linda N. Lee, Carmen Laethem, Paul A. Johnston, Harold L. Watson et Carlos V. Paya. « Secretion of Proinflammatory Cytokines and Chemokines during Amphotericin B Exposure Is Mediated by Coactivation of Toll-Like Receptors 1 and 2 ». Antimicrobial Agents and Chemotherapy 49, n^o 4 (avril 2005) : 1617–21. http://dx.doi.org/10.1128/aac.49.4.1617-1621.2005.

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ABSTRACT Amphotericin B (AmB) is a ligand of toll-like receptor 2 (TLR2). Here, we demonstrate the participation of TLR1 in AmB-induced cell activation that led to the secretion of tumor necrosis factor alpha, interleukin 6 (IL-6), and IL-8. Hence, TLR2-TLR1 coactivation serves as the underlying mechanism for the proinflammatory toxicities associated with AmB.

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Louie, Arnold, Pamela Kaw, Partha Banerjee, Weiguo Liu, George Chen et Michael H. Miller. « Impact of the Order of Initiation of Fluconazole and Amphotericin B in Sequential or Combination Therapy on Killing of Candida albicans In Vitro and in a Rabbit Model of Endocarditis and Pyelonephritis ». Antimicrobial Agents and Chemotherapy 45, n^o 2 (1 février 2001) : 485–94. http://dx.doi.org/10.1128/aac.45.2.485-494.2001.

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ABSTRACT In vitro time-kill studies and a rabbit model of endocarditis and pyelonephritis were used to define the impact that the order of exposure of Candida albicans to fluconazole (FLC) and amphotericin B (AMB), as sequential and combination therapies, had on the susceptibility of C. albicans to AMB and on the outcome. The contribution of FLC-induced resistance to AMB for C. albicans also was assessed. In vitro, AMB monotherapy rapidly killed each of four C. albicans strains; FLC alone was fungistatic. Preincubation of these fungi with FLC for 18 h prior to exposure to AMB decreased their susceptibilities to AMB for 8 to >40 h. Induced resistance to AMB was transient, but the duration of resistance increased with the length of FLC preincubation. Yeast sequentially incubated with FLC followed by AMB plus FLC (FLC→AMB+FLC) showed fungistatic growth kinetics similar to that of fungi that were exposed to FLC alone. This antagonistic effect persisted for at least 24 h. Simultaneous exposure of C. albicans to AMB and FLC [AMB+FLC(simult)] demonstrated activity similar to that with AMB alone for AMB concentrations of ≥1 μg/ml; antagonism was seen using an AMB concentration of 0.5 μg/ml. The in vitro findings accurately predicted outcomes in our rabbit infection model. In vivo, AMB monotherapy and treatment with AMB for 24 h followed by AMB plus FLC (AMB→AMB+FLC) rapidly sterilized kidneys and cardiac vegetations. AMB+FLC(simult) and FLC→AMB treatments were slower in clearing fungi from infected tissues. FLC monotherapy and FLC→AMB+FLC were both fungistatic and were the least active regimens. No adverse interaction was observed between AMB and FLC for the AMB→FLC regimen. However, FLC→AMB treatment was slower than AMB alone in clearing fungi from tissues. Thus, our in vitro and in vivo studies both demonstrate that preexposure of C. albicans to FLC reduces fungal susceptibility to AMB. The length of FLC preexposure and whether AMB is subsequently used alone or in combination with FLC determine the duration of induced resistance to AMB.

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Nobata, Shigenori, Maho Ogoshi et Yoshio Takei. « Potent cardiovascular actions of homologous adrenomedullins in eels ». American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 294, n^o 5 (mai 2008) : R1544—R1553. http://dx.doi.org/10.1152/ajpregu.00707.2007.

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Adrenomedullin (AM), known as a multifunctional hormone in mammals, forms a unique family of five paralogous peptides in teleost fish. To examine their cardiovascular effects using homologous AMs in eels, we isolated cDNAs encoding four eel AMs, and named AM1 (ortholog of mammalian AM), AM2, AM3 (paralog of AM2 generated only in teleost lineage), and AM5 according to the known teleost AM sequences. Unlike pufferfish, not only AM1 but AM2/3 and AM5 were expressed ubiquitously in various eel tissues. Synthetic mature AM1, AM2, and AM5 exhibited vasodepressor effects after intra-arterial injections, and the effects were more potent at dorsal aorta than at ventral aorta. This indicates that AMs preferentially act on peripheral resistance vessels rather than on branchial arterioles. The potency was in the order of AM2 = AM5 ≫ AM1 in both freshwater (FW) and seawater (SW) eels, which is different from the result of mammals in which AM1 is as potent as, or more potent than, AM2 when injected peripherally. The minimum effective dose of AM2 and AM5 in eels was 1/10 that of AM1 in mammals. The hypotension reached 50% at 1.0 nmol/kg of AM2 and AM5, which is much greater than atrial natriuretic peptide (20%), another potent vasodepressor hormone. Even with such hypotension, AMs did not change heart rate in eels. In addition, AM1 increased blood pressure at ventral aorta and dorsal aorta immediately after an initial hypotension at 5.0 nmol/kg, but not with AM2 and AM5. These data strongly suggest that specific receptors for AM2 and AM5 exist in eels, which differ from the AM1 receptors identified in mammals.

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Vazquez, Jose A., Maria T. Arganoza, Dina Boikov, Stephanie Yoon, Jack D. Sobel et Robert A. Akins. « Stable Phenotypic Resistance of CandidaSpecies to Amphotericin B Conferred by Preexposure to Subinhibitory Levels of Azoles ». Journal of Clinical Microbiology 36, n^o 9 (1998) : 2690–95. http://dx.doi.org/10.1128/jcm.36.9.2690-2695.1998.

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The fungicidal activity of amphotericin B (AmB) was quantitated for several Candida species. Candida albicans andC. tropicalis were consistently susceptible to AmB, with less than 1% survivors after 6 h of exposure to AmB. C. parapsilosis and variants of C. lusitaniae andC. guilliermondii were the most resistant, demonstrating 50 to 90% survivors in this time period and as high as 1% survival after a 24-h exposure time. All Candida species were killed (<1% survivors) after 24 h of exposure to AmB. In contrast, overnight exposure to either fluconazole or itraconazole resulted in pronounced increases in resistance to subsequent exposures to AmB. Most dramatically, C. albicans was able to grow in AmB cultures after azole preexposure. Several other Candida species did not grow in AmB but showed little or no reduction in viability after up to 24 h in AmB. Depending on the growth conditions,Candida cells preexposed to azoles may retain AmB resistance for days after the azoles have been removed. If this in vitro antagonism applies to the clinical setting, treatment of patients with certain antifungal combinations may not be beneficial. The ability of some Candida isolates to survive transient exposures to AmB was not reflected in the in vitro susceptibility changes as measured by standard MIC assays. This finding should be considered in studies attempting to correlate patient outcome with in vitro susceptibilities of clinical fungal isolates. Patients who fail to respond to AmB may be infected with isolates that are classified as susceptible by standard in vitro assays but that may be resistant to transient antifungal exposures which may be more relevant in the clinical setting.

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Goldblum, David, Kaspar Rohrer, Beatrice E. Frueh, Regula Theurillat, Wolfgang Thormann et Stefan Zimmerli. « Ocular Distribution of Intravenously Administered Lipid Formulations of Amphotericin B in a Rabbit Model ». Antimicrobial Agents and Chemotherapy 46, n^o 12 (décembre 2002) : 3719–23. http://dx.doi.org/10.1128/aac.46.12.3719-3723.2002.

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ABSTRACT Little is known about the ocular penetration of amphotericin B (AMB) and its lipid formulations, the current drug of choice in fungal endophthalmitis. The ocular distribution of AMB lipid complex (ABLC), liposomal AMB (L-AMB), and AMB deoxycholate (D-AMB) was studied in a rabbit model. D-AMB (1 mg/kg of body weight/day), ABLC (5 mg/kg/day), or L-AMB (5 mg/kg/day) was given intravenously to rabbits as a single dose or as repeated daily doses on 7 consecutive days after induction of unilateral uveitis by intravitreal injection of endotoxin. AMB concentrations in aqueous humor, vitreous humor, and plasma were determined by high-pressure liquid chromatography 16 h after administration of a single dose or 24 h after the last of seven doses. After single-dose administration, L-AMB achieved at least eightfold-higher AMB concentrations in the aqueous of inflamed eyes than ABLC or D-AMB (1.21 ± 0.58 μg/ml versus 0.14 ± 0.04 and 0.11 ± 0.09 μg/ml, respectively). At that time point no drug was detectable in the vitreous. After 7 days of treatment, the concentration of AMB in the vitreous was higher after treatment with L-AMB (0.47 ± 0.21 μg/ml) than after treatment with ABLC (0.27 ± 0.18 μg/ml) and D-AMB (0.16 ± 0.04 μg/ml). Similarly, AMB concentration in the aqueous was higher after repeated doses of L-AMB (0.73 ± 0.43 μg/ml) than after repeated doses of ABLC (0.03 ± 0.02 μg/ml) or D-AMB (0.13 ± 0.06 μg/ml). No AMB was detected in noninflamed eyes. Following systemic administration, AMB distribution to the eye is inflammation dependent and occurs sequentially, first to the aqueous and then to the vitreous. Compared to D-AMB and ABLC, L-AMB reaches higher drug concentrations in both ocular compartments.

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Nimtrakul, Pataranapa, Waree Tiyaboonchai et Supaporn Lamlertthon. « Amphotericin B Loaded Nanostructured Lipid Carriers for Parenteral Delivery : Characterization, Antifungal and In vitro Toxicity Assessment ». Current Drug Delivery 16, n^o 7 (3 octobre 2019) : 645–53. http://dx.doi.org/10.2174/1567201816666190729145223.

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Background: Amphotericin B (AmB) is important for the treatment of systemic fungal infections. Nowadays, only intravenous administration (IV) of AmB has been available due to its low aqueous solubility. Two forms of AmB are available. The first is Fungizone®, a mixture of AmB and sodium deoxcycholate that produces severe nephrotoxicity. The second are lipid-based formulations that reduce nephrotoxicity, but they are costly and require higher dose than Fungizone®. Thus, a cheaper delivery system with reduced AmB toxicity is required. Objective: To develop and characterize AmB loaded-nanostructured lipid carriers (AmB-loaded NLCs) for IV administration to reduce AmB toxicity. Methods: AmB-loaded NLCs with different solid lipids were prepared by the high-pressure homogenization technique. Their physicochemical properties and the drug release profile were examined. The molecular structure of AmB, antifungal and hemolysis activities of developed AmB-loaded NLCs were also evaluated. Results: AmB-loaded NLCs ~110 to ~140 nm in diameter were successfully produced with a zeta potential of ~-19 mV and entrapment efficiency of ~75%. In vitro release showed fast release characteristics. AmB-loaded NLCs could reduce the AmB molecular aggregation as evident from the absorbance ratio of the first to the fourth peak showing a partial aggregation of AmB. This result suggested that AmB-loaded NLCs could offer less nephrotoxicity compared to Fungizone®. In vitro antifungal activity of AmB-loaded NLCs showed a minimum inhibitory concentration of 0.25 µgmL-1. Conclusion: AmB-loaded NLCs present high potential carriers for effective IV treatment with prolonged circulation time and reduced toxicity.

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Olson, Jon, Matthew Slarve et Jill Adler-Moore. « 1639. Efficacy of Voriconazole Prophylaxis Followed by Therapeutic Liposomal Amphotericin B for the Treatment of Murine Pulmonary Aspergillosis Caused by Azole-Resistant Aspergillus fumigatus Strains ». Open Forum Infectious Diseases 5, suppl_1 (novembre 2018) : S45. http://dx.doi.org/10.1093/ofid/ofy209.109.

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Abstract Background Antifungal treatment for pulmonary aspergillosis is more difficult if the fungal strain causing the infection is azole resistant. To investigate this problem, we used a murine model of pulmonary aspergillosis caused by azole-resistant Aspergillus fumigatus strains V29 and V45, and compared treatment with voriconazole (Vr, oral 40 mg/kg, bid) or liposomal amphotericin B (L-AmB, 5 mg/kg, IV) used alone or in combination. Methods Mice (n = 14/gp) were immunosuppressed with 24 mg/kg triamcinolone acetonide, IP, d-3, d-1, and d+1 relative to fungal challenge (d0). For 2 groups, Vr was given prophylactically (proph) d-3, d-2, d-1 followed by L-AmB or buffer, d+1, d+2, and d+3. The other groups were given Vr, L-AmB, Vr+L-AmB, or buffer d+1, d+2, and d+3. On d0, mice were given 1.3 to 1.6 × 107A. fumigatus spores intranasally (Vr MIC = 64 μg/mL, V29; Vr MIC = 8 μg/mL, V45). On d+3, lungs were collected from 7 mice/gp and fungal burden determined by plating for colony forming units; 7 mice/gp were then monitored for morbidity to d+21. Results Optimum treatment was observed when Vr was given proph, followed by L-AmB post-challenge (Vr/L-AmB), with better survival (100%) for both fungal strains vs. buffer or Vr post-challenge (P ≤ 0.04); for V29, significantly better survival was also seen with Vr/L-AmB vs. L-AmB or Vr+L-AmB post-challenge (P ≤ 0.01). For strain V45, lung fungal burden was significantly lower for Vr/L-AmB versus all other treatments (P ≤ 0.04), while for strain V29, fungal burden was lower for the Vf/L-AmB and L-AmB post-challenge groups versus the other groups, but the differences were not significant. Notably, although the lung fungal burden with Vr proph and Vr postchallenge were both similar to the buffer control, Vr proph yielded significantly better survival than Vr post-challenge (P ≤ 0.001). Conclusion These preclinical observations demonstrate that combining L-AmB with Vr for the postchallenge treatment of pulmonary aspergillosis caused by azole-resistant strains is not an effective therapeutic option. However, the results do show that Vr proph, but not Vr postchallenge, can have some limited antifungal activity, and can significantly enhance the antifungal effects of post-challenge L-AmB. This regimen could be considered in areas where there is a high incidence of azole-resistant A. fumigatus. Disclosures All authors: No reported disclosures.

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Koizumi, Tomonobu, Keishi Kubo, Toshimichi Kaneki, Masayuki Hanaoka, Toshihide Hayano, Takayuki Miyahara, Kazuyoshi Okada et al. « Pharmacokinetic Evaluation of Amphotericin B in Lung Tissue : Lung Lymph Distribution after Intravenous Injection and Airspace Distribution after Aerosolization and Inhalation of Amphotericin B ». Antimicrobial Agents and Chemotherapy 42, n^o 7 (1 juillet 1998) : 1597–600. http://dx.doi.org/10.1128/aac.42.7.1597.

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ABSTRACT We have studied the pharmacokinetics of amphotericin B (AmB) in lung lymph circulation and bronchial-wash fluid after intravenous infusion and inhalation, respectively. For two experiments with awake sheep, we used lung lymph fistulas and tracheotomy. In experiment 1, AmB concentrations in plasma and lung lymph after intravenous infusion of AmB (1 mg/kg of body weight) over 1.5 h were measured. The mean peak in plasma level was 756.0 ± 188.8 ng/ml at 3 h after the start of infusion, and the level then decreased gradually to 194.8 ± 28.9 ng/ml at 24 h. The stable and maximal levels in lung lymph last 5 to 9 h after the start of AmB infusion. The concentrations in lung lymph after 9 h were slightly higher than those in plasma. Thus, the lung lymph-to-plasma ratio of AmB concentrations increased gradually during infusion, and the ratio was more than 1.0 after the end of infusion, suggesting that AmB could be easily moved from plasma to pulmonary interstitium and/or lung lymph circulation. In another experiment, 5 or 30 mg of aerosol AmB was inhaled, and the concentration of AmB in the bronchial-wash fluid was determined by bronchoalveolar lavage. The peak AmB concentration in the fluid was observed at 0.5 h. After that, AmB was slowly eliminated over 24 h. The area under the concentration-time curve for 30 mg of inhaled AmB was higher than that for 5 mg, but maximum concentrations of AmB in serum for 5 and 30 mg were almost similar. These observations identify the pharmacokinetic characteristics of AmB in the lung and may provide a new insight into the strategy for clinical treatment of fungal pneumonia.

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Otsubo, Takakazu, Shigefumi Maesaki, Mohammad Ashraf Hossain, Yoshihiro Yamamoto, Kazunori Tomono, Takayoshi Tashiro, Junzo Seki, Yoshifumi Tomii, Satoru Sonoke et Shigeru Kohno. « In Vitro and In Vivo Activities of NS-718, a New Lipid Nanosphere Incorporating Amphotericin B, againstAspergillus fumigatus ». Antimicrobial Agents and Chemotherapy 43, n^o 3 (1 mars 1999) : 471–75. http://dx.doi.org/10.1128/aac.43.3.471.

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ABSTRACT We evaluated the in vitro and in vivo potencies of a new lipid nanosphere that incorporates amphotericin B (AmB), NS-718, againstAspergillus fumigatus. The in vitro activity of NS-718 (the MIC at which 90% of strains are inhibited [MIC90], 0.25 μg/ml) against 18 isolates of A. fumigatus was similar to that of deoxycholate AmB (D-AmB; Fungizone; MIC90, 0.25 μg/ml), but NS-718 was more potent than liposomal AmB (L-AmB; AmBisome; MIC90, 1.0 μg/ml). The in vivo efficacy of NS-718 in a rat model of invasive pulmonary aspergillosis was compared with those of D-AmB and L-AmB. A low dose (1 mg/kg of body weight) of L-AmB was ineffective (survival rate, 0%), although equivalent doses of D-AmB and NS-718 were more effective (survival rate, 17%). However, a higher dose of NS-718 (3 mg/kg) was more effective (survival rate, 100%) than equivalent doses of D-AmB and L-AmB (survival rate, 0%). To explain these differences, pharmacokinetic studies showed higher concentrations of AmB in the plasma of rats treated with NS-718 than in the plasma of those treated with D-AmB. Our results suggest that NS-718, a new preparation of AmB, is a promising antifungal agent with activity against pulmonary aspergillosis.

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Van Etten, Els W. M., Lorna E. T. Stearne-Cullen, Marian T. Ten Kate et Irma A. J. M. Bakker-Woudenberg. « Efficacy of Liposomal Amphotericin B with Prolonged Circulation in Blood in Treatment of Severe Pulmonary Aspergillosis in Leukopenic Rats ». Antimicrobial Agents and Chemotherapy 44, n^o 3 (1 mars 2000) : 540–45. http://dx.doi.org/10.1128/aac.44.3.540-545.2000.

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ABSTRACT The therapeutic efficacy of long-circulating polyethylene glycol-coated liposomal amphotericin B (AMB) (PEG-AMB-LIP) was compared with that of AMB desoxycholate (Fungizone) in a model of severe invasive pulmonary aspergillosis in persistently leukopenic rats as well as in temporarily leukopenic rats. PEG-AMB-LIP treatment (intravenous administration) consisted of a single, or double (every 72 h), or triple (every 72 h) dose of 10 mg of AMB/kg of body weight, a double dose (every 72 h) of 14 mg of AMB/kg, or a 5-day treatment (every 24 h) with 6 mg/kg/dose. AMB desoxycholate was administered for 10 consecutive days at 1 mg of AMB/kg/dose. Treatment was started 30 h after fungal inoculation, at which time mycelial growth was firmly established. Both persistently and temporarily leukopenic rats died between 4 and 9 days after Aspergillus fumigatus inoculation when they were left untreated or after treatment with a placebo. In persistently leukopenic rats, a single dose of PEG-AMB-LIP (10 mg/kg) was as effective as the 10-day treatment with AMB desoxycholate (at 1 mg/kg/dose) in significantly prolonging the survival of rats infected with A. fumigatus and in reducing the dissemination of A. fumigatus to the liver. Prolongation of PEG-AMB-LIP treatment (double or triple dose or 5-day treatment) did not further improve efficacy. For temporarily leukopenic rats no major advances in efficacy were achieved compared to those for persistently leukopenic rats, probably because the leukocyte numbers in blood were restored too late in the course of infection.

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Hatabu, Toshimitsu, Tsuyoshi Takada, Nao Taguchi, Mamoru Suzuki, Kumiko Sato et Shigeyuki Kano. « Potent Plasmodicidal Activity of a Heat-Induced Reformulation of Deoxycholate-Amphotericin B (Fungizone) against Plasmodium falciparum ». Antimicrobial Agents and Chemotherapy 49, n^o 2 (février 2005) : 493–96. http://dx.doi.org/10.1128/aac.49.2.493-496.2005.

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ABSTRACT The emergence and spread of drug-resistant Plasmodium falciparum continue to pose problems in malaria chemotherapy. Therefore, it is necessary to identify new antimalarial drugs and therapeutic strategies. In the present study, the activity of a heat-treated form of amphotericin B (HT-AMB) against P. falciparum was evaluated. The efficacy and toxicity of HT-AMB were also compared with those of the standard formulation (AMB). HT-AMB showed significant activity against a chloroquine-resistant strain (strain K-1) and a chloroquine-susceptible strain (strain FCR-3) in vitro. The 50% inhibitory concentrations of HT-AMB were 0.32 ± 0.03 μg/ml for strain K-1 and 0.33 ± 0.03 μg/ml for strain FCR-3. In the presence of 1.0 μg of HT-AMB per ml, only pyknotic parasites were observed after 24 h of incubation of early trophozoites (ring forms). However, when late trophozoites and schizonts were cultured with 1.0 μg of HT-AMB per ml, those forms multiplied to ring forms but the number of infected erythrocytes did not increase. These results indicate that HT-AMB possesses potent antiplasmodial activity and that the drug is more effective against the ring-form stage than against the late trophozoite and schizont stages. HT-AMB was observed to have little cytotoxic effect against a human liver cell line (Chang liver cells). In conclusion, the results suggest that HT-AMB has promising properties and merits further in vivo investigations as a treatment for falciparum malaria.

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Pyrgos, Vasilios, Diane Mickiene, Tin Sein, Margaret Cotton, Andrea Fransesconi, Isaac Mizrahi, Martha Donoghue et al. « Effects of Immunomodulatory and Organism-Associated Molecules on the Permeability of an In Vitro Blood-Brain Barrier Model to Amphotericin B and Fluconazole ». Antimicrobial Agents and Chemotherapy 54, n^o 3 (7 décembre 2009) : 1305–10. http://dx.doi.org/10.1128/aac.01263-09.

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ABSTRACT Amphotericin B (AMB) is used to treat fungal infections of the central nervous system (CNS). However, AMB shows poor penetration into the CNS and little is known about the factors affecting its permeation through the blood-brain barrier (BBB). Therefore, we studied immunomodulatory and organism-associated molecules affecting the permeability of an in vitro BBB model to AMB. We examined the effects of interleukin-1 beta (IL-1β), tumor necrosis factor alpha (TNF-α), lipopolysaccharide (LPS), lipoteichoic acid (LTA), zymosan (ZYM), dexamethasone (DEX), cyclosporine, and tacrolimus on transendothelial electrical resistance (TEER); endothelial tight junctions; filamentous actin; and permeability to deoxycholate AMB (DAMB), liposomal AMB (LAMB), and fluconazole. Proinflammatory cytokines and organism-associated molecules significantly decreased the mean TEER by 40.7 to 100% (P ≤ 0.004). DEX increased the mean TEER by 18.2 to 26.4% (P ≤ 0.04). TNF-α and LPS increased the permeability to AMB by 8.2 to 14.5% compared to that for the controls (1.1 to 2.4%) (P ≤ 0.04). None of the other molecules affected the model's permeability to AMB. By comparison, the BBB model's permeability to fluconazole was >78% under all conditions studied, without significant differences between the controls and the experimental groups. LPS and TNF-α decreased tight-junction protein zona occludens 1 (ZO-1) between endothelial cells. In conclusion, IL-1β, ZYM, and LTA increased the permeability of the BBB to small ions but not to AMB, whereas TNF-α and LPS, which disrupted the endothelial layer integrity, increased the permeability to AMB.

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Machard, Sophie, Frederic Theodoro, Henri Benech, Jean-Marc Grognet et Eric Ezan. « A Sensitive Amphotericin B Immunoassay for Pharmacokinetic and Distribution Studies ». Antimicrobial Agents and Chemotherapy 44, n^o 3 (1 mars 2000) : 546–50. http://dx.doi.org/10.1128/aac.44.3.546-550.2000.

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ABSTRACT Since currently used assays of amphotericin B (AMB) lack sensitivity or are not easily adaptable in all laboratories, we have developed an enzyme immunoassay for AMB in biological fluids and tissues. Antibodies to AMB were raised in rabbits after administration of an AMB-bovine serum albumin conjugate. The enzymatic tracer was obtained by coupling AMB via its amino group to acetylcholinesterase (EC 3.1.1.7). These reagents were used for the development of a competitive immunoassay performed on microtitration plates. The limit of quantification was 100 pg/ml in plasma and 1 ng/g in tissues. The plasma assay was performed directly without extraction on a minimal volume of 0.1 ml. The intra- and interassay coefficients of variation were in the range of 5 to 17%, and the recoveries were 92 to 111% for AMB added to human plasma. The assay was applied to a pharmacokinetic study with mice given AMB intraperitoneally at the dose of 1 mg/kg. The drug distribution in selected compartments (plasma, liver, spleen, lung, and brain) was monitored until 72 h after administration. In conclusion, our assay is at least 100-fold more sensitive than previously described bioassays or chromatographic determinations of AMB and may be useful in studying the tissue pharmacokinetics of new AMB formulations and in drug monitoring in clinical situations.

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Mei, Ying-Wu, Zhan-Qing Yang, Wei Wang, De-Guang Song, Xu-Ming Deng et Ju-Xiong Liu. « Acute Electrical Stimulation of Nucleus Ambiguus Enhances Immune Function in Rats ». Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques 35, n^o 4 (septembre 2008) : 441–47. http://dx.doi.org/10.1017/s0317167100009094.

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Background:Up to now, many “immunoactive” brain areas have been identified, such a hypothalamic nuclei, brain reward system; but the nucleus ambiguous (Amb), a nucleus nervi vagis of medulla oblongata, was less well studied in neuroimmunomodulation.Methods:In order to obtain more profound comprehension and more knowledge on Amb, we studied the effect of acute electrical stimulation of Amb on thymus and spleen activity in rat. A stimulator was applied to stimulate the Amb of the anaesthetic rats using the parameter at 100μAx5ms x100 Hz every 1s for 1 min. The levels of TGF-β and thymosin-β4 mRNA in thymus, the release of IL-2 and IL-6 at splenocyte in vitro and splenic lymphocyte proliferation were measured at hour 0.5,1,2,3 following the electrical stimulation.Results:The results showed that concanavalin A (Con A)-induced splenic lymphocyte proliferation and the release of IL-2 and IL-6 were all significantly enhanced at 0.5, 1, and 2 h following effective Amb stimulation as compared to in the control group. However, as compared to in the control group, the levels of TGF-β and thymosin-β4 mRNA in the thymus were both remarkably reduced at 0.5, 1, and 2 h following effective Amb stimulation.Conclusions:These findings reveal that the Amb participates in the modulation of animal immune functions.

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Adhikari, Kajiram. « In vitro Toxicity Study of Reconstituted Amphotericin B - Lipid Derivatives Dry Powder for Nebulization ». Dhaka University Journal of Pharmaceutical Sciences 15, n^o 2 (2 janvier 2017) : 127–34. http://dx.doi.org/10.3329/dujps.v15i2.30925.

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The aim of the present research work was to evaluate the safety of reconstituted dry powder amphotericin B (AmB) inhalation via nebulizer. This study was carried out on respiratory cell lines (A549, Calu-3, NR 8383), kidney cells (293T/17), human red blood cells (RBC) and aerosol properties were determined by Andersen Cascade Impactor (ACI). AmB, a lipid derivative reconstituted dry powder was formulated by lyophilization and reconstituted into distilled water at AmB concentration at 4 mg/ml. The value of MMAD, FPF were obtained as 1.7 to 2.05 ?m and 70 to 80%, respectively. The cytotoxicity test carried out by MTT assay of lipid formulations revealed a very low toxicity on respiratory cell lines such as kidney cells, than pure AmB at concentration 1 to 8 ?g/ml of AmB. In-vitro cytotoxicity results showed less toxicity to human red blood cells (RBC) than pure AmB at concentration 1 to 8 ?g/ml of AmB.Dhaka Univ. J. Pharm. Sci. 15(2): 127-134, 2016 (December)

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McDonnell, T. J., S. W. Chang, J. Y. Westcott et N. F. Voelkel. « Role of oxidants, eicosanoids, and neutrophils in amphotericin B lung injury in rats ». Journal of Applied Physiology 65, n^o 5 (1 novembre 1988) : 2195–206. http://dx.doi.org/10.1152/jappl.1988.65.5.2195.

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Administration of the antifungal antibiotic amphotericin B (AmB, 1 mg/kg) to intact rats produced acute lung injury as indicated by the extravascular leakage of protein and water and histological examination. The injury was neutrophil independent because it occurred in neutropenic rats. AmB produced vasoconstriction and injury in isolated lungs perfused with a cell- and plasma-free physiological solution, and this injury was independent of pulmonary perfusion pressure. In vivo administration of AmB produced an increase in lung tissue and plasma-oxidized glutathione disulfide (GSSG) indicative of oxidant stress. In the isolated lung, the radical scavengers p-hydroxybenzoate (methylparaben) and catalase attenuated AmB lung injury as did 1-phenyl-3-pyrazolidone (Phenidone), a combined radical scavenger and lipoxygenase/cyclooxygenase inhibitor, and the leukotriene antagonist CGP 35949B. Methylparaben and CGP 35949B prevented the elevation in lung tissue leukotriene C4 and B4 levels noted after AmB. We conclude that AmB in the rat produces neutrophil-independent lung injury, which is associated with oxidant stress and eicosanoid production.

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Binet, A., et J. Bolard. « Recovery of hepatocytes from attack by the pore former amphotericin B ». Biochemical Journal 253, n^o 2 (15 juillet 1988) : 435–40. http://dx.doi.org/10.1042/bj2530435.

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Sublytic amounts of the pore former Amphotericin B (AmB) induced transient movements of Na and K ions across the hepatocyte plasma membranes without altering the intracellular free Ca ion concentration. The presence of 1-5 microM-AmB induced leakage of up to 80% of the intracellular K+ within 3 min, followed by Na+ entry without loss of cell viability. A repair process occurred after 3-10 min, which restored the initial cationic concentrations. Progressive binding of AmB to the cells could be observed by following the disappearance of the intense excitonic dichroic doublet of free AmB. It was shown that the amount of AmB binding, responsible for the Na+ and K+ movements, was low (approx. 16% of total AmB). The recovery process occurred when higher amounts of AmB bound to the cells, and was mediated by Na+/K+-ATPase. The c.d. spectrum of AmB bound to isolated hepatocyte plasma membranes, indicated that during this step AmB formed a complex with cholesterol, similar to that formed by the binary mixture in water.

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Turtinen, Lloyd W., David N. Prall, Lindsay A. Bremer, Rachel E. Nauss et Scott C. Hartsel. « Antibody Array-Generated Profiles of Cytokine Release from THP-1 Leukemic Monocytes Exposed to Different Amphotericin B Formulations ». Antimicrobial Agents and Chemotherapy 48, n^o 2 (février 2004) : 396–403. http://dx.doi.org/10.1128/aac.48.2.396-403.2004.

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ABSTRACT Cytokine antibody arrays were used to establish the profiles of cytokine release from THP-1 monocytes exposed to different amphotericin B (AMB) drug delivery systems. Fungizone (FZ) and Amphotec (ABCD) caused the release of significantly more inflammatory molecules and the release of inflammatory molecules at higher levels than either AmBisome (L-AMB) or Abelcet (ABLC) after 6 h of treatment. Specifically, tumor necrosis factor alpha (TNF-α), interleukin-8 (IL-8), GRO-(αβγ), monocyte chemoattractant protein-1 (MCP-1), RANTES, IL-10, and IL-6 were detected and semiquantified with a chemiluminscence imaging system. TNF-α, IL-8, and MCP-1 were the most predominant; however, little if any TNF-α was present in ABLC- or L-AMB-treated cultures. The TNF- α and IL-8 levels determined by quantitative enzyme-linked immunosorbent assay correlated with the relative cytokine levels measured by using the antibody arrays. Although the viabilities of THP-l monocytes in all AMB-treated cultures were similar by trypan blue exclusion, the amount of lactic dehydrogenase released was significantly larger in FZ- and ABCD-treated cultures than in L-AMB- and ABLC-treated cultures, indicating more membrane perturbations with those formulations. Membrane cation channel formation was also measured in model cholesterol-containing large unilamellar vesicles to directly assess the ion channel formation ability of the system. Only FZ and ABCD induced significant ion currents at concentrations less than 1.5 × 10−5 M. These results may help provide rationales for the immediate cytokine-mediated side effects observed with FZ and ABCD and the reduced side effects observed with L-AMB and ABLC.

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Lewis, Russell E., Guangling Liao, Jinggou Hou, Georgios Chamilos, Randall A. Prince et Dimitrios P. Kontoyiannis. « Comparative Analysis of Amphotericin B Lipid Complex and Liposomal Amphotericin B Kinetics of Lung Accumulation and Fungal Clearance in a Murine Model of Acute Invasive Pulmonary Aspergillosis ». Antimicrobial Agents and Chemotherapy 51, n^o 4 (29 janvier 2007) : 1253–58. http://dx.doi.org/10.1128/aac.01449-06.

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ABSTRACT The reformulation of amphotericin B (AMB) into a lipid complex (AMB lipid complex [ABLC]) or liposomal carrier (liposomal AMB [L-AMB]) changes the rate and extent of drug distribution to the lung. The importance of pharmacokinetic differences among the various lipid AMB formulations in the treatment of invasive pulmonary aspergillosis (IPA) remains unknown. We compared the kinetics of AMB lung accumulation and fungal clearance of ABLC- and L-AMB-treated mice with acute IPA. BALB/c mice were immunosuppressed with cyclophosphamide and cortisone before intranasal inoculation with 1.5 × 106 Aspergillus fumigatus 293 conidia. ABLC or L-AMB was administered in daily intravenous doses (1, 5, or 10 mg/kg of body weight), starting 12 h after infection and continuing until day 5. At predetermined times (0, 24, 72, and 120 h), mice were euthanized, and lungs were harvested for determinations of lung fungal burdens (quantitative PCR) and total AMB lung tissue concentrations. Both ABLC and L-AMB were effective at reducing lung fungal burdens at doses of ≥5 mg/kg/day. Clearance of A. fumigatus during the first 24 h was associated with AMB tissue concentrations of >4 μg/g. At 5 mg/kg/day, ABLC produced a more rapid fungal clearance than did L-AMB, but at the end of therapy, fungal burden reductions were similar for both formulations and were not improved with higher dosages. These data suggest that ABLC delivers active AMB to the lung more rapidly than does L-AMB, resulting in faster Aspergillus clearance in an experimental model of IPA. However, pharmacodynamic differences between the two formulations were less apparent when mice were dosed at 10 mg/kg/day.

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Zarif, Leila, John R. Graybill, David Perlin, Laura Najvar, Rosie Bocanegra et Raphael J. Mannino. « Antifungal Activity of Amphotericin B Cochleates against Candida albicans Infection in a Mouse Model ». Antimicrobial Agents and Chemotherapy 44, n^o 6 (1 juin 2000) : 1463–69. http://dx.doi.org/10.1128/aac.44.6.1463-1469.2000.

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ABSTRACT Cochleates are lipid-based supramolecular assemblies composed of natural products, negatively charged phospholipid, and a divalent cation. Cochleates can encapsulate amphotericin B (AmB), an important antifungal drug. AmB cochleates (CAMB) have a unique shape and the ability to target AmB to fungi. The minimal inhibitory concentration and the minimum lethal concentration against Candida albicans are similar to that for desoxycholate AmB (DAMB; Fungizone). In vitro, CAMB induced no hemolysis of human red blood cells at concentrations of as high as 500 μg of AmB/ml, and DAMB was highly hemolytic at 10 μg of AmB/ml. CAMB protect ICR mice infected with C. albicans when the agent is administered intraperitoneally at doses of as low as 0.1 mg/kg/day. In a tissue burden study, CAMB, DAMB, and AmBisome (liposomal AmB; LAMB) were effective in the kidneys, but in the spleen CAMB was more potent than DAMB at 1 mg/kg/day and was equivalent to LAMB at 10 mg/kg/day. In summary, CAMB are highly effective in treating murine candidiasis and compare well with AmBisome and AmB.

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Corral, M. J., E. González-Sánchez, M. Cuquerella et J. M. Alunda. « In VitroSynergistic Effect of Amphotericin B and Allicin on Leishmania donovani and L. infantum ». Antimicrobial Agents and Chemotherapy 58, n^o 3 (23 décembre 2013) : 1596–602. http://dx.doi.org/10.1128/aac.00710-13.

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ABSTRACTCurrent monotherapy against visceral leishmaniasis has serious side effects, and resistantLeishmaniastrains have been identified. Amphotericin B (AmB) has shown an extraordinary antileishmanial efficacy without emergence of resistance; however, toxicity has limited its general use. Results obtained showed, using a fixed-ratio analysis, that the combination of diallyl thiosulfinate (allicin) and AmB ranged from moderately synergic to synergic at low concentrations (0.07 μM AmB plus 35.45 μM allicin induced 95% growth inhibition). None of the treatments, alone or in combination, had noticeable adverse effects on macrophages (Mϕ) in the concentration range examined (allicin, 0.5, 1, 5 and 10 μM; AmB, 0.05, 0.075, and 0.1 μM). Allicin, AmB, or the combination did not affect the infection rate (percentage of infected Mϕ) ofLeishmania. Allicin enhanced the activity of AmB on intracellular amastigotes ofLeishmania donovaniandL. infantum(ca. 45% reduction of amastigote burden with 0.05 μM AmB plus 10 μM allicin); this represented nearly a 2-fold reduction in the 50% inhibitory concentration (IC50) of the antibiotic added alone. Results point toward the possible utility of testing this combinationin vivoto reduce the toxicity associated with monotherapy with AmB.

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Spreghini, Elisabetta, Carmelo Massimo Maida, Maria Eleonora Milici, Giorgio Scalise et Francesco Barchiesi. « Posaconazole Activity against Candida glabrata after Exposure to Caspofungin or Amphotericin B ». Antimicrobial Agents and Chemotherapy 52, n^o 2 (3 décembre 2007) : 513–17. http://dx.doi.org/10.1128/aac.01447-07.

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ABSTRACT We evaluated the effects of sequential therapy with caspofungin (CAS) or amphotericin B (AMB) followed by posaconazole (POS) against Candida glabrata. The susceptibilities to POS of yeast cells pre-exposed to CAS or AMB were identical to those of untreated cells as shown by standard Clinical and Laboratory Standards Institute broth dilution, cell viability, and disk diffusion methods. We then investigated the activity of sequential regimens in an experimental model of disseminated candidiasis. CAS given at 1 mg/kg/day for 2 days followed by POS at either 15 or 30 mg/kg/day significantly reduced the counts compared to the controls, but this treatment was not superior to the use of CAS alone. Also, sequential regimens with AMB given at 1 mg/kg/day for 2 days followed by POS (AMB/POS) were effective at reducing the fungal burden against the controls. In addition, AMB/POS with both doses of the triazole were significantly more effective than AMB alone. Overall, our data showed that there is no therapeutic advantage in using CAS followed by POS, whereas an induction therapy with AMB followed by a maintenance regimen with POS might be a suitable strategy in managing C. glabrata infections.

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Lalloo, Umesh G., Lauren Komarow, Judith A. Aberg, David B. Clifford, Evelyn Hogg, Ashley McKhann, Aggrey Bukuru et al. « Higher Dose Oral Fluconazole for the Treatment of AIDS-related Cryptococcal Meningitis (HIFLAC)—report of A5225, a multicentre, phase I/II, two-stage, dose-finding, safety, tolerability and efficacy randomised, amphotericin B-controlled trial of the AIDS Clinical Trials Group ». PLOS ONE 18, n^o 2 (13 février 2023) : e0281580. http://dx.doi.org/10.1371/journal.pone.0281580.

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Background The WHO recommended 1200mg/day of fluconazole (FCZ) in the induction phase of cryptococcal meningitis (CM) in HIV prior to 2018 in regions where amphotericin-B (AMB) was unavailable. A 2-stage AMB-controlled, dose-escalation study to determine the maximum tolerated dose and the safety/efficacy of an induction-consolidation strategy of higher doses FCZ (1200mg-2000mg/day), adjusted for weight and renal function (eGFR)in adults with CM was undertaken. Methods In Stage-1, three induction doses of FCZ (1200mg/day, 1600mg/day and 2000mg/day) were tested in sequential cohortsand compared with AMB in a 3:1 ratio. A particular dose was not tested in Stage 2 if there were significant predetermined safety or efficacy concerns. In Stage-2, the 1200mg dose was excluded per protocol because of increased mortality, and participants were randomised to 1600mg, 2000mg FCZ or AMB in a 1:1:1 ratio. Findings One hundred and sixty eight participants were enrolled with 48, 50, and 48 in the AMB, 1600mg and 2000mg cohorts. The Kaplan Meier proportion for mortality (90% CI) at 10 and 24 weeks for AMB was 17% (10, 29) and 24% (15, 37), compared to 20% (12, 32) and 30% (20, 43) for 1600mg, and 33% (23, 46) and 38% (27, 51) for 2000mg/day FCZ. With the exception of a higher incidence of gastrointestinal side effects in the 2000mg cohort, both induction doses of FCZ were safe and well tolerated. There were no life-threatening changes in electrocardiogram QTc which were similar across all doses of FCZ and AMB. The median (IQR) change in log10 cryptoccal colony forming units (CFU) from week 0 to week 2 was -8(-4.1,-1.9) for AMB; -2.5(-4.0, -1.4) for 1600mg FCZ and -8 (-3.2, -1.0) for 2000mg FCZ. The proportion (90% CI) CSF CM negative at 10 weeks was 81%(71,90) for AMB; 56%(45,69) for 1600mg FCZ and 60%(49,73) for 2000mg FCZ. Interpretation Induction phase weight and renal-adjusted doses of 1600mg and 2000mg/day FCZ for CM were safe and well tolerated except for increased GI side effects in the 2000mg/day dose, and had similar times to achieve CSF sterilization, but took significantly longer than AMB. The WHO recommended 1200mg FCZ was associated with a high mortality. While not statistically significant, mortality was numerically lower in the AMB compared to 1600mg and 2000mg FCZ These data make a case for a phase 3 study of higher doses of FZC.

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Chapoval, Svetlana P., Teresa Neeno, Christopher J. Krco, Eric V. Marietta, Jerry Harders et Chella S. David. « HLA-DQ6 and HLA-DQ8 Transgenic Mice Respond to Ragweed Allergens and Recognize a Distinct Set of Epitopes on Short and Giant Ragweed Group 5 Antigens ». Journal of Immunology 161, n^o 4 (15 août 1998) : 2032–37. http://dx.doi.org/10.4049/jimmunol.161.4.2032.

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Abstract We have investigated the genetic and molecular basis of immune responsiveness to short ragweed (SRW) (Ambrosia artemisiifolia) extract, and group 5 allergens from short and giant (Ambrosia trifida) ragweed using transgenic mice expressing DQ6 (HLA-DQA1*0103, HLA-DQB1*0601) and DQ8 (HLA-DQA1*0301, HLA-DQB1*0302) genes in class II knockout (Aβ0) mice. Panels of overlapping peptides spanning the Amb a 5 and Amb t 5 Ags were synthesized. Mice were immunized with whole SRW extract or individual peptides s.c. and lymph node cells (LNC) were challenged in vitro. Strong T cell responses to SRW extract were measured in both HLA-DQ transgenic mice, while control, HLA-DQ6−/DQ8−/H-2Aβ0, mice were unresponsive. IL-5 and IL-10 were the primary cytokines produced by in vitro challenged LNC of SRW-primed transgenic mice. HLA-DQ6-restricted T cell responses were detected to all three peptides of Amb t 5 and two determinants (residues 1–20 and 11–30) on Amb a 5. In contrast, LNC of HLA-DQ8 mice did not recognize peptide 11–30 of Amb t 5 Ag, but recognized several Amb a 5 determinants. The immune response in transgenic mice was dependent upon CD4+ T cells and was HLA-DQ restricted. Primed with purified Amb t 5, both transgenics recognized peptide 21–40, and an additional DQ6-restricted epitope was found within residue 1–20. SRW-immunized HLA-DQ6 mice respond to peptide 11–30 of Amb a 5, while HLA-DQ8 mice strongly recognize peptide 1–20. These results demonstrate the specificity of HLA class II polymorphism in allergen sensitivity and pave the way for developing antagonistic peptides for desensitization.

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Wasan, K. M., et J. S. Conklin. « Evaluation of renal toxicity and antifungal activity of free and liposomal amphotericin B following a single intravenous dose to diabetic rats with systemic candidiasis. » Antimicrobial Agents and Chemotherapy 40, n^o 8 (août 1996) : 1806–10. http://dx.doi.org/10.1128/aac.40.8.1806.

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Since fungal infections are prevalent in diabetic patients, in whom treatment is often complicated by underlying renal disease and dyslipidemias, the purpose of the present study was to determine if the antifungal activity and nephrotoxic effects of amphotericin B (AmB) and liposomal AmB (L-AmB) are different in nondiabetic (normolipidemic) rats compared with those in diabetic (dyslipidemic) rats with systemic candidiasis. Non diabetic and diabetic rats infected with Candida albicans received a single intravenous dose of either AmB (0.8 mg of AmB per kg of body weight), L-AmB (0.8, 2, or 4 mg of AmB per kg), or an equivalent volume of normal saline (1 ml). Renal function was assessed by insulin clearance, and antifungal activity was determined by measuring the numbers of CFU of C. albicans that were present in the right kidney following drug treatment. AmB at 0.8 mg/kg and L-AmB at 0.8, 2, and 4 mg/kg are effective antifungal agents in both diabetic and nondiabetic rats. However, while there was approximately a 4-fold decline in the mean number of CFU per gram of kidney in nondiabetic rats, there was only approximately a 2.5-fold decline for the comparable dose (AmB, 0.8 mg/kg) in diabetic rats. There also appeared to be a similar fold reduction of L-AmB at all of the dosages tested. AmB treatment significantly improved renal function in diabetic and nondiabetic rats with systemic candidiasis. Although L-AmB at all doses tested significantly improved renal function in diabetic rats with systemic candidiasis, only L-AmB at doses of 2 and 4 mg/kg significantly improved renal function in nondiabetic rats with systemic candidiasis. These findings suggest that following administration of a single intravenous dose, AmB and L-AmB appear to be less effective in killing C. albicans isolates in diabetic than in nondiabetic rats, while they were found to improve the renal functions of rats in both treatment groups.

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Varlam, Despina E., Mustafa M. Siddiq, Lance A. Parton et Holger Rüssmann. « Apoptosis Contributes to Amphotericin B- Induced Nephrotoxicity ». Antimicrobial Agents and Chemotherapy 45, n^o 3 (1 mars 2001) : 679–85. http://dx.doi.org/10.1128/aac.45.3.679-685.2001.

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ABSTRACT The aim of this study was to investigate whether apoptosis contributes to nephrotoxicity caused by amphotericin B (AmB). By detecting apoptosis-specific DNA fragmentation, it is demonstrated that proximal tubular cells (LLC-PK1) and medullary interstitial cells (RMIC) respond with programmed cell death when treated with therapeutic doses of AmB. Concomitant application of AmB and recombinant human insulin-like growth factor-1 (rhIGF-1), a known antiapoptotic agent, abrogated apoptosis in vitro. To validate that the observed apoptotic effects on renal tissue culture cells are applicable to an in vivo setting, an animal model was used for verification. Therefore, Sprague-Dawley rats were treated with AmB. The drug caused hypokalemia, decreased weight gain, loss of renal concentrating ability, and dehydration in a dose-dependent fashion. Microscopic examination of renal tissue sections revealed apoptotic alterations predominantly in proximal and distal tubular epithelial cells. To verify that the observed clinical side effects were linked to apoptosis, rhIGF-1 was applied concomitantly with AmB. In all animals, rhIGF-1 prevented the above-mentioned clinical side effects. Moreover, significantly reduced apoptosis was observed in renal tissue sections of these animals, indicating the relevance of apoptosis in nephrotoxicity. This is the first report to demonstrate that AmB induces apoptosis in the rat kidney in a dose-dependent fashion. The incidence of apoptosis correlates with renal toxicity and can be abrogated by concomitant treatment with rhIGF-1.

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