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1
van der Schaft, Theo L., Wim C. de Bruijnz, Cornelia M. Mooy e Paul T. V. M. de Jong. "Basal laminar deposit in the aging peripheral human retina". Graefe's Archive for Clinical and Experimental Ophthalmology 231, n. 8 (agosto 1993): 470–75. http://dx.doi.org/10.1007/bf02044234.
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van der Schaft, Theo L., Cornelia M. Mooy, Wim C. de Bruijn, Fred T. Bosman e Paul T. V. M. de Jong. "Immunohistochemical light and electron microscopy of basal laminar deposit". Graefe's Archive for Clinical and Experimental Ophthalmology 232, n. 1 (gennaio 1994): 40–46. http://dx.doi.org/10.1007/bf00176436.
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van der Schaft, Theo L. "Is Basal Laminar Deposit Unique for Age-Related Macular Degeneration?" Archives of Ophthalmology 109, n. 3 (1 marzo 1991): 420. http://dx.doi.org/10.1001/archopht.1991.01080030122052.
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Lee, William R. "Is Basal Laminar Deposit Unique for Age-Related Macular Degeneration?" Archives of Ophthalmology 110, n. 1 (1 gennaio 1992): 15. http://dx.doi.org/10.1001/archopht.1992.01080130017009.
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Song, Delu, Imran Mohammed, Rupak Bhuyan, Takashi Miwa, Allison Lesher Williams, Damodar Gullipalli, Sayaka Sato, Ying Song, Joshua L. Dunaief e Wen-Chao Song. "Retinal Basal Laminar Deposits in Complement fH/fP Mouse Model of Dense Deposit Disease". Investigative Opthalmology & Visual Science 59, n. 8 (10 luglio 2018): 3405. http://dx.doi.org/10.1167/iovs.18-24133.
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van der Schaft, Theo L. "Is Basal Laminar Deposit Unique for Age-Related Macular Degeneration?-Reply". Archives of Ophthalmology 110, n. 1 (1 gennaio 1992): 16. http://dx.doi.org/10.1001/archopht.1992.01080130017010.
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Kliffen, M. "The APO*E3-Leiden mouse as an animal model for basal laminar deposit". British Journal of Ophthalmology 84, n. 12 (1 dicembre 2000): 1415–19. http://dx.doi.org/10.1136/bjo.84.12.1415.
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Toomey, Christopher B., Una Kelly, Daniel R. Saban e Catherine Bowes Rickman. "Regulation of age-related macular degeneration-like pathology by complement factor H". Proceedings of the National Academy of Sciences 112, n. 23 (19 maggio 2015): E3040—E3049. http://dx.doi.org/10.1073/pnas.1424391112.
Testo completoAbstract (sommario):
Complement factor H (CFH) is a major susceptibility gene for age-related macular degeneration (AMD); however, its impact on AMD pathobiology is unresolved. Here, the role of CFH in the development of AMD pathology in vivo was interrogated by analyzing aged Cfh+/− and Cfh−/− mice fed a high-fat, cholesterol-enriched diet. Strikingly, decreased levels of CFH led to increased sub-retinal pigmented epithelium (sub-RPE) deposit formation, specifically basal laminar deposits, following high-fat diet. Mechanistically, our data show that deposits are due to CFH competition for lipoprotein binding sites in Bruch’s membrane. Interestingly and despite sub-RPE deposit formation occurring in both Cfh+/− and Cfh−/− mice, RPE damage accompanied by loss of vision occurred only in old Cfh+/− mice. We demonstrate that such pathology is a function of excess complement activation in Cfh+/− mice versus complement deficiency in Cfh−/− animals. Due to the CFH-dependent increase in sub-RPE deposit height, we interrogated the potential of CFH as a previously unidentified regulator of Bruch’s membrane lipoprotein binding and show, using human Bruch’s membrane explants, that CFH removes endogenous human lipoproteins in aged donors. Thus, advanced age, high-fat diet, and decreased CFH induce sub-RPE deposit formation leading to complement activation, which contributes to RPE damage and visual function impairment. This new understanding of the complicated interactions of CFH in AMD-like pathology provides an improved foundation for the development of targeted therapies for AMD.
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Sura, Amol A., Ling Chen, Jeffrey D. Messinger, Thomas A. Swain, Gerald McGwin, K. Bailey Freund e Christine A. Curcio. "Measuring the Contributions of Basal Laminar Deposit and Bruch's Membrane in Age-Related Macular Degeneration". Investigative Opthalmology & Visual Science 61, n. 13 (13 novembre 2020): 19. http://dx.doi.org/10.1167/iovs.61.13.19.
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Sarks, Shirley, Svetlana Cherepanoff, Murray Killingsworth e John Sarks. "Relationship of Basal Laminar Deposit and Membranous Debris to the Clinical Presentation of Early Age-Related Macular Degeneration". Investigative Opthalmology & Visual Science 48, n. 3 (1 marzo 2007): 968. http://dx.doi.org/10.1167/iovs.06-0443.
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Espinosa-Heidmann, Diego G., John Sall, Eleut P. Hernandez e Scott W. Cousins. "Basal Laminar Deposit Formation in APO B100 Transgenic Mice: Complex Interactions between Dietary Fat, Blue Light, and Vitamin E". Investigative Opthalmology & Visual Science 45, n. 1 (1 gennaio 2004): 260. http://dx.doi.org/10.1167/iovs.03-0910.
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Cousins, Scott W., Diego G. Espinosa-Heidmann, Anastasia Alexandridou, John Sall, Sander Dubovy e Karl Csaky. "The Role of Aging, High Fat Diet and Blue Light Exposure in an Experimental Mouse Model for Basal Laminar Deposit Formation". Experimental Eye Research 75, n. 5 (novembre 2002): 543–53. http://dx.doi.org/10.1006/exer.2002.2047.
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Zarbin, M. A. "Age-Related Macular Degeneration: Review of Pathogenesis". European Journal of Ophthalmology 8, n. 4 (ottobre 1998): 199–206. http://dx.doi.org/10.1177/112067219800800401.
Testo completoAbstract (sommario):
Age-related macular degeneration is a condition (a) characterized by accumulation of membranous debris on both sides of the retinal pigment epithelium (RPE) basement membrane. Clinical manifestations of drusen, atrophy of the RPE/choriocapillaris, RPE detachment, and choroidal new vessel (CNV) formation occur after age 50 years. A hypothetical pathogenic sequence of events consistent with known data is: 1) RPE dysfunction (e.g., precipitated by an inherited susceptibility and/or environmental exposure); 2) accumulation of intracellular material in the RPE (e.g., accumulation of normal substrate material that is not enzymatically degraded properly vs. abnormal substrate material); 3) abnormal accumulation of extracellular material (basal laminar and basal linear deposit); 4) change in Bruch's membrane composition (e.g., increased lipid deposition and protein crosslinking); 5) change in Bruch's membrane parmeability to nutrients (e.g., impaired diffusion of water soluble plasma constituents across Bruch's membrane); and 6) response of the RPE to metabolic distress (i.e., atrophy vs. CNV growth). Histopathological and clinical studies indicate that areas of choroidal ischemia often are seen near CNVs in AMD patients. In response to decreased oxygen delivery/metabolic “distress”, the RPE may elaborate substances leading to CNV growth. Perhaps RPE atrophy, followed by choriocapillaris and photoreceptor atrophy, is a response to decreased nutrients/increasing metabolic abnormalities in areas of excessive accumulation of extracellular debris. Unanswered questions regarding AMD include: 1) is AMD an ocular manifestation of a systemic disease or purely an ocular disease?; 2) what determines whether CNVs vs.atrophy of the RPE-choriocapillaris-photoreceptors develops?; and 3) what induces the maturation of CNVs into an inactive scar, and what limits the growth of most CNVs to the area centralis?
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Kogaya, Y., S. Kim, S. Haruna e T. Akisaka. "Heterogeneity of distribution pattern at the electron microscopic level of heparan sulfate in various basement membranes." Journal of Histochemistry & Cytochemistry 38, n. 10 (ottobre 1990): 1459–67. http://dx.doi.org/10.1177/38.10.1698204.
Testo completoAbstract (sommario):
Using the high-iron diamine thiocarbohydrazide silver proteinate (HID-TCH-SP) staining technique and enzymatic digestion, we investigated the ultrastructural distribution pattern of heparan sulfate side chains of heparan sulfate proteoglycan (HSPG) in various basement membranes (nerve, capillary, oral epithelial, muscle, and dental basement membranes). Four different distribution patterns of stain deposits were identified as heparan sulfate on the basis of enzymatic degradation by heparitinase. In some basement membranes associated with tooth germs and oral epithelium, HID-TCH-SP stain deposits were regularly located at both sides of the lamina densa, but few were observed in the lamina densa itself. In nerve, muscle, and capillary basement membranes, the stain deposits were localized at the external side of the lamina densa adjacent to the underlying connective tissue, but were not found in the laminae lucida and densa. In the internal basal lamina of junctional epithelium of gingiva, the stain deposits were detected mainly in the lamina lucida region. Finally, in some dental and oral epithelial basement membranes, the stain deposits were randomly distributed throughout both laminae lucida and densa. Thus, the present study demonstrated distinct differences in heparan sulfate distribution pattern among various basement membranes, suggesting their architectural heterogeneity.
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Aplin, J. D., S. Campbell e T. D. Allen. "The extracellular matrix of human amniotic epithelium: ultrastructure, composition and deposition". Journal of Cell Science 79, n. 1 (1 novembre 1985): 119–36. http://dx.doi.org/10.1242/jcs.79.1.119.
Testo completoAbstract (sommario):
Ultrastructural comparisons have been made between human amnion extracellular matrix in tissue and cell culture. Immunochemical analysis of matrix deposited by monolayers of cultured amnion epithelial cells has also been undertaken. The basal cell surfaces are highly invaginated with an associated basal lamina that is more electron dense at the distal tips of basal cell processes where hemidesmosomes are frequent. Immediately below the lamina densa is a zone rich in collagen bundles. In the underlying stroma two types of fibril predominate, one striated of 50 nm diameter and one of 18 nm diameter. The observations suggest that at gestational term the epithelial cells are still active in the production of matrix. Secretion appears to occur into invaginations in the basal cell surface where a loosely organized mixture of stromal-type and basal laminal-type aggregates is formed. In culture on plastic, cells also deposit a mixture of basal laminal (type IV collagen + laminin) and stromal (collagens type I + III) components as well as fibronectin. However, segregation into a true basal lamina with underlying stroma does not occur in vitro, suggesting the need for an organized subcellular template to complete matrix morphogenesis. The in vitro and in vivo evidence suggest that the epithelium contributes to the subjacent dense collagenous zone as well as to the basal lamina.
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Notomi, Shoji, Kenji Ishihara, Nikolaos E. Efstathiou, Jong-Jer Lee, Toshio Hisatomi, Takashi Tachibana, Eleni K. Konstantinou et al. "Genetic LAMP2 deficiency accelerates the age-associated formation of basal laminar deposits in the retina". Proceedings of the National Academy of Sciences 116, n. 47 (7 novembre 2019): 23724–34. http://dx.doi.org/10.1073/pnas.1906643116.
Testo completoAbstract (sommario):
The early stages of age-related macular degeneration (AMD) are characterized by the accumulation of basal laminar deposits (BLamDs). The mechanism for BLamDs accumulating between the retinal pigment epithelium (RPE) and its basal lamina remains elusive. Here we examined the role in AMD of lysosome-associated membrane protein-2 (LAMP2), a glycoprotein that plays a critical role in lysosomal biogenesis and maturation of autophagosomes/phagosomes. LAMP2 was preferentially expressed by RPE cells, and its expression declined with age. Deletion of the Lamp2 gene in mice resulted in age-dependent autofluorescence abnormalities of the fundus, thickening of Bruch’s membrane, and the formation of BLamDs, resembling histopathological changes occurring in AMD. Moreover, LAMP2-deficient mice developed molecular signatures similar to those found in human AMD—namely, the accumulation of APOE, APOA1, clusterin, and vitronectin—adjacent to BLamDs. In contrast, collagen 4, laminin, and fibronectin, which are extracellular matrix proteins constituting RPE basal lamina and Bruch’s membrane were reduced in Lamp2 knockout (KO) mice. Mechanistically, retarded phagocytic degradation of photoreceptor outer segments compromised lysosomal degradation and increased exocytosis in LAMP2-deficient RPE cells. The accumulation of BLamDs observed in LAMP2-deficient mice was eventually followed by loss of the RPE and photoreceptors. Finally, we observed loss of LAMP2 expression along with ultramicroscopic features of abnormal phagocytosis and exocytosis in eyes from AMD patients but not from control individuals. Taken together, these results indicate an important role for LAMP2 in RPE function in health and disease, suggesting that LAMP2 reduction may contribute to the formation of BLamDs in AMD.
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Kogaya, Y., e K. Furuhashi. "Ultrastructural distribution of sulfated glycosaminoglycans in epithelial-mesenchymal interface of developing rat tooth germs." Journal of Histochemistry & Cytochemistry 35, n. 5 (maggio 1987): 585–93. http://dx.doi.org/10.1177/35.5.2435784.
Testo completoAbstract (sommario):
We investigated the ultrastructural distribution of sulfated glycosaminoglycans in the epithelial-mesenchymal interface of tooth germs by use of the high-iron diamine thiocarbohydrazide silver proteinate (HID-TCH-SP) staining and enzymatic digestion method. At an early stage in odontoblast differentiation, HID-TCH-SP stain deposits were sparsely distributed in the basement membrane and in the intercellular spaces. Subsequently, as formation of the initial predentin matrix began, HID-TCH-SP stain deposits were densely distributed in the interfibrillar spaces and the basement membrane. Testicular hyaluronidase digested most of those in the progenitor pre-dentin, whereas those in the region of basal lamina resisted enzymatic digestion. Testicular hyaluronidase-resistant HID-TCH-SP stain deposits were susceptible to heparitinase, indicating that the sulfated glycosaminoglycan in the basal lamina is heparan sulfate. Furthermore, the heparan sulfate tended to be regularly arranged at the sites of internal and external lamina densa. However, as progenitor pre-dentin matrix formation proceeded, the numbers of stain deposits temporarily increased and their distribution pattern became irregular, finally tending to disappear with the disruption of basal lamina.
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de Guzman, Roche C., Jeffrey A. Loeb e Pamela J. VandeVord. "Electrospinning of Matrigel to Deposit a Basal Lamina-Like Nanofiber Surface". Journal of Biomaterials Science, Polymer Edition 21, n. 8-9 (1 gennaio 2010): 1081–101. http://dx.doi.org/10.1080/09205063.2010.11964027.
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de Guzman, Roche C., Jeffrey A. Loeb e Pamela J. VandeVord. "Electrospinning of Matrigel to Deposit a Basal Lamina-Like Nanofiber Surface". Journal of Biomaterials Science, Polymer Edition 21, n. 8 (1 maggio 2010): 1081–101. http://dx.doi.org/10.1163/092050609x12457428936116.
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Cousins, Scott W., Diego G. Espinosa-Heidmann, Anastasia Alexandridou, John Sall, Sander Dubovy e Karl Csaky. "Erratum to “The role of aging, high fat diet and blue light exposure in an experimental mouse model for basal laminar deposit formation” by S.W. Cousins, D.G. Espinosa-Heidmann, A. Alexandridou, J. Sall, S. Dubovy and K. Csaky [Experimental Eye Research 75 (2002) 543–553]". Experimental Eye Research 76, n. 4 (aprile 2003): 517. http://dx.doi.org/10.1016/s0014-4835(03)00025-3.
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Anglister, L., e U. J. McMahan. "Basal lamina directs acetylcholinesterase accumulation at synaptic sites in regenerating muscle." Journal of Cell Biology 101, n. 3 (1 settembre 1985): 735–43. http://dx.doi.org/10.1083/jcb.101.3.735.
Testo completoAbstract (sommario):
In skeletal muscles that have been damaged in ways which spare the basal lamina sheaths of the muscle fibers, new myofibers develop within the sheaths and neuromuscular junctions form at the original synaptic sites on them. At the regenerated neuromuscular junctions, as at the original ones, the muscle fibers are characterized by junctional folds and accumulations of acetylcholine receptors and acetylcholinesterase (AChE). The formation of junctional folds and the accumulation of acetylcholine receptors is known to be directed by components of the synaptic portion of the myofiber basal lamina. The aim of this study was to determine whether or not the synaptic basal lamina contains molecules that direct the accumulation of AChE. We crushed frog muscles in a way that caused disintegration and phagocytosis of all cells at the neuromuscular junction, and at the same time, we irreversibly blocked AChE activity. New muscle fibers were allowed to regenerate within the basal lamina sheaths of the original muscle fibers but reinnervation of the muscles was deliberately prevented. We then stained for AChE activity and searched the surface of the new muscle fibers for deposits of enzyme they had produced. Despite the absence of innervation, AChE preferentially accumulated at points where the plasma membrane of the new muscle fibers was apposed to the regions of the basal lamina that had occupied the synaptic cleft at the neuromuscular junctions. We therefore conclude that molecules stably attached to the synaptic portion of myofiber basal lamina direct the accumulation of AChE at the original synaptic sites in regenerating muscle. Additional studies revealed that the AChE was solubilized by collagenase and that it remained adherent to basal lamina sheaths after degeneration of the new myofibers, indicating that it had become incorporated into the basal lamina, as at normal neuromuscular junctions.
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Reale, Enrico, Stephanie Groos, Ute Eckardt, Claus Eckardt e Liliana Luciano. "New Components of ‘Basal Laminar Deposits’ in Age-Related Macular Degeneration". Cells Tissues Organs 190, n. 3 (2009): 170–81. http://dx.doi.org/10.1159/000187632.
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Anderson, M. J. "Nerve-induced remodeling of muscle basal lamina during synaptogenesis." Journal of Cell Biology 102, n. 3 (1 marzo 1986): 863–77. http://dx.doi.org/10.1083/jcb.102.3.863.
Testo completoAbstract (sommario):
To identify mechanisms that regulate the deposition of the junctional basal lamina during synaptogenesis, immunocytochemical experiments were carried out on cultured nerve and muscle cells derived from Xenopus laevis embryos. In some experiments successive observations were made on individual muscle cells after pulse-labeling with a fluorescent monoclonal antibody specific for a basal lamina proteoglycan. In others, old and new proteoglycan molecules were differentially labeled with antibody conjugated to contrasting fluorochromes. These observations revealed that surface deposits of antibody-labeled proteoglycan remain morphologically stable for several days on developing muscle cells. Over the same period, however, new sites of proteoglycan accumulation formed that contained primarily those antigenic sites recently exposed at the cell surface. When muscle cells became innervated by cholinergic neurites, new proteoglycan accumulations were induced at the developing neuromuscular junctions, and these too were composed almost exclusively of recently deposited antigen. In older muscle cultures, where many cells possessed relatively high background concentrations of antigen over their surfaces, developing neuromuscular junctions initially showed a markedly reduced proteoglycan site-density compared with the adjacent, extrajunctional muscle surface. Much of this perineural region eventually became filled with dense, nerve induced proteoglycan plaques at later stages of synapse development. Motoneurons thus appear to have two, superficially paradoxical effects on muscle basal lamina organization. They first cause the removal of any existing, extrajunctional proteoglycan from the path of cell contact, and then induce the deposition of dense plaques of recently synthesized proteoglycan within the developing junctional basal lamina. This observation suggests that the proteolytic enzyme systems that have already been implicated in tissue remodeling may also contribute to the inductive interaction between nerve and muscle cells during synaptogenesis.
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Lommatzsch, Albrecht, Pia Hermans, Bernhard Weber e Daniel Pauleikhoff. "Complement factor H variant Y402H and basal laminar deposits in exudative age-related macular degeneration". Graefe's Archive for Clinical and Experimental Ophthalmology 245, n. 11 (18 agosto 2007): 1713–16. http://dx.doi.org/10.1007/s00417-007-0649-7.
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Yde, Jacob C., N. Tvis Knudsen, Nicolaj K. Larsen, Christian Kronborg, Ole B. Nielsen, Jan Heinemeier e Jesper Olsen. "The presence of thrust-block naled after a major surge event: Kuannersuit Glacier, West Greenland". Annals of Glaciology 42 (2005): 145–50. http://dx.doi.org/10.3189/172756405781812907.
Testo completoAbstract (sommario):
AbstractThrust-block naled in front of Kuannersuit Glacier, West Greenland, appears to have formed during the termination of a terrestrial surge event by a combination of enhanced winter runoff, rapid advance of the glacier terminus, and proglacial stress release by thrusting and stacking of naled blocks. This process is equivalent to the formation of thrust-block moraines. The thrust-block naled consists of at least seven thrust sheets, which are characterized by stratified ice with beds composed of a lower debris-rich lamina, an intermediate dispersed lamina and a top clean-ice lamina, and underlain by frozen outwash deposits. The thrust-block naled differs from basal stratified ice in the absence of internal deformation structures, a relatively low debris concentration, a clay-rich particle-size distribution and a preferential sorting of lighter minerals. The oxygen isotope composition of the thrust-block naled is indistinguishable from δ18O values from meteoric glacier ice and bulk meltwater, but different from basal stratified ice facies. The d–δD relationship indicates that thrust-block naled has been formed by freezing of successive thin layers of bulk waters with variable isotopic composition, whereas basal stratified ice has developed in a subglacial environment with regelation. This work shows that the association between proglacial naled and rapidly advancing glaciers may have significant consequences for the proglacial geomorphology and the interpretation of basal ice layers.
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Empeslidis, T., U. Imrani, A. Vardarinos, N. Menassa e S. Banerjee. "Spontaneous Resolution of Retinal Pigment Epithelial Detachments and Visual Improvement in Patient with MPGN II: A Case Report". Case Reports in Ophthalmological Medicine 2012 (2012): 1–4. http://dx.doi.org/10.1155/2012/864198.
Testo completoAbstract (sommario):
A 31-year-old female suffering from membranoproliferative glomerulonephritis type II (MPGN II) presented to the Eye Casualty Department reporting a history of blurred and distorted vision. The patient appeared to have drusenoid retinal epithelial detachments and minimal intraretinal fluid. The subretinal deposits, basal lamina drusen, and pigment epithelial detachment appeared to resemble a “stars in the sky” picture with no symmetry between the eyes. The retinal pigment epithelial detachments improved and flattened over 18 month. and the best corrected visual acuity improved in the most affected eye. There was no evidence of neovascularization, and the intraretinal fluid disappeared spontaneously.
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Kamyshanskiy, Yevgeniy, Olga Kostyleva, Maida Tussupbekova, Leila Stabayeva, Gulnazira Imanbayeva, Raihan Nygyzbayeva, Evgeniy Kotov e Denis Kossitsyn. "Аllergic Basal Deciduitis as a Reason of Recurrent Antenatal Fetal Death". Open Access Macedonian Journal of Medical Sciences 9, n. C (26 giugno 2021): 80–83. http://dx.doi.org/10.3889/oamjms.2021.6129.
Testo completoAbstract (sommario):
BACKGROUND: Allergic diseases of pregnant women are associated with chronic placental insufficiency and the development of immunopathological conditions of unknown etiology in a child in postnatal life. Pregnancy with bronchial asthma is often complicated by intrauterine growth retardation, preeclampsia, and antenatal fetal death. AIM: The objective was to present a clinical case of recurrent antenatal fetal death in the third trimester in women with bronchial asthma under controlled course. CASE REPORT: Pregnancy proceeded without clinical signs of exacerbation of bronchial asthma and allergic status. However, chronic inflammation with eosinophilia in the intervillous space and the basal lamina was revealed in the placenta tissue. Eosinophilia of the intervillous area was accompanied by obliteration of the intervillous area by fibrin deposits. CONCLUSION: We suppose that immunological inflammation at the fetoplacental unit level can occur regardless of the mother’s allergic status. Moreover, it is likely that the objective state of the mother in the presence of an allergic disease does not reflect the presence/absence of an immunological process in the placenta, as the immunological inflammatory process can develop in different compartments (at the level of the mother’s body and the placental-fetal compartment) with varying degrees of severity.
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Bendella, Mohamed, Madani Benyoucef, Amine Cherif e Miloud Benhamou. "Ichnology and sedimentology of the “Argiles de Saïda” formation (Callovo-Oxfordian) of the Djebel Brame (Tiaret, Algeria)". Bulletin de la Société Géologique de France 182, n. 5 (1 settembre 2011): 417–25. http://dx.doi.org/10.2113/gssgfbull.182.5.417.
Testo completoAbstract (sommario):
Abstract The focus of this note is an ichnological study of the “Argiles de Saïda” formation (Callovo-Oxfordian) in the Djebel Brame, a region representing the eastern extremity of the Tlemcenian domain and marked by rhythmic clay-sandstone sedimentation. From a lithostratigraphic viewpoint, the formation is composed of two units with a distinct sequential organization and trace fossil content. These deposits are characterized by weak to moderate bioturbation, eleven ichnogenera were found: Bergaueria, Chondrites, Diplichnites, Megagrapton, Neonereites, Nereites, Ophiomorpha, Palaeophycus, Rhizocorallium, Taenidium and Thalassinoides. The basal unit is mainly characterized by fine sediments organized into small turbiditic sequences. Most of the beds are around one centimeter thick except for the conglomerate layer, channelized by the debris flow. This layer is heterometric and polygenic. The soles of the beds are generally marked by flute and groove casts, proof of their erosion by the currents. Most of these siliciclastic beds are organized around a repetitive model, with a massive base and flat, parallel and/or wavy laminae at the summit. Occasionally there are also beds of complex ripple marks, fluid escape structures and convoluted laminae. This sedimentation was deposited in an offshore environment, below the storm action influence threshold. Most of ichnogenera are associated with episodic silica-clastic deposits. The disappearance of Bergaueria and Diplichnites ichnogenera corresponds to the period when the basal conglomerate layer was established, and constituted stressful conditions for the organisms responsible for the two traces. Conversely, above this level, the appearance of Taenidium and Thalassinoides seems to correspond to a colonization by opportunistic endobenthic organisms. The weak hydrodynamism of the depositional environment, as well as the associated trace fossils content, point to the distal part of the Cruziana ichnofacies. The other, coarser, unit is an alternation of greenish clays, carbonate rocks and occasionally slumped sandstone. It is dominated by storm sequences. The more proximal summit shows shoreface deposits marked by phases of emersion. As well as episodes of storms and oolitic deposition, there are, at the top of this unit, deposits from a reefal environment (“Subreefal Layer”). These are indicative of shallow depths. Observable trace fossil content points to the most proximal part of the Cruziana ichnofacies. The trace fossil distribution and sedimentology both reveal hitherto undisclosed bathymetric fluctuations. A major fluctuation, most likely due to tectonic instability, was recorded before the second sequence was established. These results call for the biostratigraphic and structural study of the “Argiles de Saïda” formation in the Tlemcenian domain.
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da Cruz-Landim, Carminda, e Silvana Beani Poiani. "Cephalic salivary gland ultrastructure of worker and queen eusocial bees (Hymenoptera, Apidae)". Animal Biology 59, n. 3 (2009): 299–311. http://dx.doi.org/10.1163/157075609x454935.
Testo completoAbstract (sommario):
AbstractEusocial bees present a pair of functional salivary glands in head, the cephalic salivary glands. These glands from workers and queens of two eusocial bee species, Apis mellifera and Scaptotrigona postica, were examined at different life stages using routine transmission electron microscopy techniques to correlate morphology and gland functions. Ultrastructural features of worker and queen glands ducts and secretory units were descriptively compared between species. The duct cells present basal plasma membrane invaginations reaching the apical region. Intercellular space and invaginations contain material of similar electron-density to the basal lamina, suggesting that substances might be directly absorbed from the hemolymph to the gland lumen. The secretory cells are rich in smooth endoplasmic reticulum, mitochondria, Golgi, and vesicles typical of lipid secretion. Secretory cells in S. postica become flattened with age in contrast to A. mellifera, where cells remained cuboidal. Mitochondria are associated with secretory vesicles and may become lipid deposits. A possible role of worker and queen secretion is discussed, taking changes in caste gland morphology and their function in the colony into account.
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Beaudry, Luc M., e Gilbert Prichonnet. "Formation of De Geer Moraines Deposited Subglacially, Central Québec". Géographie physique et Quaternaire 49, n. 3 (30 novembre 2007): 337–61. http://dx.doi.org/10.7202/033059ar.
Testo completoAbstract (sommario):
ABSTRACT This paper presents a model for the genesis of De Geer moraines in the Chapais and Radisson areas, Québec. The model is mainly based on faciès and deformation structure analysis. Three facies associations have been identified: (1) sorted sediments that form foreset laminations dipping downglacier. Till lenses or glacial diamictons are found within the sorted sediments or form a surficial layer on the proximal side of the sections; (2) a non-fissile and poorly compacted till overlies and deforms sorted sediments. Laminae of finely sorted sediments may be incorporated in the till; (3) a fissile and compact till commonly lies on the basal till sheet. All three facies associations feature deformation structures (faults, folds, load and drag structures) which indicate an upglacier origin. The model proposed is an emplacement of De Geer moraines in bottom crevasses by an active glacier. In areas where meltwaters were channelized, sediments accumulated in the crevasses as foreset laminations. Till filled the crevasses in areas remote from meltwater flow. Glacial activity remobilized the basal till locally and pushed it toward bottom crevasses located downglacier, or overturned large layers of till. Finally, in areas located even further laterally, meltwaters had almost no effect and the moraines were formed by plastering of till in the crevasses. The three faciès associations are part of a continuum beginning with the moraines composed of sorted sediments and grading laterally into the moraines formed of fissile and compact till. This continuum is described for the first time.
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Schneider, Jay A., e Joseph G. Carter. "Evolution and phylogenetic significance of cardioidean shell microstructure (Mollusca, Bivalvia)". Journal of Paleontology 75, n. 3 (maggio 2001): 607–43. http://dx.doi.org/10.1017/s002233600003969x.
Testo completoAbstract (sommario):
The shell microstructure of Carboniferous and Triassic permophorids; Triassic and Recent carditids; Devonian, Carboniferous, and Triassic crassatelloideans; and Jurassic through Recent cardioideans is examined in a phylogenetic context, using separate microstructural and morphologic data sets, as well as a combined data set. The microstructural and morphologic data sets are significantly incongruent, but the combined data set suggests that modiomorphoideans (modiomorphids and permophorids) are basal to crassatelloideans; crassatelloideans are basal to carditids (includingSeptocardia), and carditids are basal to cardiids. On the other hand, the possibility of direct permophorid ancestry for the carditid-cardiid clade cannot be excluded, as suggested by the retention of permophorid-like matted (transitional nacreous-porcelaneous) structure in some early carditids and cardiids. In the absence of stratigraphic data and other evidence for phylogenetic relationships, shell microstructure offers limited potential for assessing subfamily-level phylogenetic relationships within the Cardioidea. This is because of microstructural convergences reflecting biomechanical adaptations for fracture control and abrasion resistance, and possibly also selection for metabolic economy of secretion in tropical, oligotrophic habitats. General evolutionary trends in cardiid shell microstructure are nevertheless apparent: Cretaceous cardiids completely replaced an ancestral laminar, matted structure in their inner shell layer with non-laminar porcelaneous structures; evolved better defined CL structure, stronger reflection of the shell margins, and increased thickness or secondary loss of the ancestral prismatic outer shell layer; and, inProtocardia(Pachycardium)stantoni, added inductural deposition. Some Cenozoic cardiids then evolved wider first-order crossed lamellae, non-denticular composite prisms, composite fibrous prisms, ontogenetic submergence of a juvenile non-denticular composite prismatic outer shell layer into the CL middle shell layer, or ontogenetic submergence of the inner part of a juvenile fibrous prismatic outer shell layer into the CL middle shell layer.The shell microstructure ofHemidonax donaciformisis unusual for a cardioidean, and suggests closer affinities with the superfamily Tellinoidea than with the superfamily Cardioidea.Extensive inductural deposits inProtocardia(Pachycardium)stantoniraise the possibility that photosymbiosis evolved among some Mesozoic members of the Protocardiinae, thereby increasing the likelihood that this feature has evolved several times independently in the Cardiidae.Cemented, calcareous periostracal granules or spines are known to occur in modiolopsoideans, mytiloideans, modiomorphids, permophorids, trigonioids, astartids, cardiids, myoids, pholadomyoids, and septibranchoids. Consequently, the presence of these structures is not necessarily indicative of close anomalodesmatan affinities.
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Ackerman, Jeanne, Erick F. Gonzalez e Enid Gilbert-Barness. "Immunological Studies of the Placenta in Maternal Connective Tissue Disease". Pediatric and Developmental Pathology 2, n. 1 (gennaio 1999): 19–24. http://dx.doi.org/10.1007/s100249900085.
Testo completoAbstract (sommario):
Maternal connective tissue disease is an important cause of second-trimester fetal loss. In order to assess the pathological changes in the placenta in maternal connective tissue disease, we reviewed the clinical histories and performed histologic and immunofluorescence studies on nine placentas: five from mothers with systemic lupus erythematosus (SLE), two from mothers with mixed connective tissue disease (MCTD), one from a mother with rheumatoid arthritis (RA), and one from a mother without prior known connective tissue disease. Excessive intervillous fibrin deposition and infarction were noted in all cases. Immunofluorescent and immunoperoxidase studies showed deposits of fibrinogen, IgG, IgM, IgA, and complement 3 (C3) localized to the trophoblast basement membrane (TBM). Electron microscopy documented thickening of the trophoblast basal lamina in three SLE placentas examined. The use of immunofluorescence may be enhanced further if antitrophoblast antibodies can be linked to placental compromise.
33
Baas, Jaco H., Niall D. Tracey e Jeff Peakall. "Sole marks reveal deep-marine depositional process and environment: Implications for flow transformation and hybrid-event-bed models". Journal of Sedimentary Research 91, n. 9 (30 settembre 2021): 986–1009. http://dx.doi.org/10.2110/jsr.2020.104.
Testo completoAbstract (sommario):
ABSTRACT Deposits of sediment gravity flows in the Aberystwyth Grits Group (Silurian, west Wales, United Kingdom) display evidence that sole marks are suitable for reconstructing depositional processes and environments in deep-marine sedimentary successions. Based on drone imagery, 3D laser scanning, high-resolution sedimentary logging, and detailed descriptions of sole marks, an outcrop 1600 m long between the villages of Aberarth and Llannon was subdivided into seven lithological units, representing: a) mudstone-poor, coarse-grained and thick-bedded submarine channel fills, dominated by the deposits of erosive high-density turbidity currents with flute marks; b) mudstone-rich levee deposits with thin-bedded, fine-grained sandstones formed by low-density turbidity currents that scoured the bed to form flute marks; c) channel–lobe transition-zone deposits, dominated by thick beds, formed by weakly erosive, coarse-grained hybrid events, with pronounced mudstone-rich or sandstone-dominated debritic divisions and groove marks below basal turbiditic divisions, and with subordinate amounts of turbidites and debris-flow deposits; d) tabular, medium- to thick-bedded turbiditic sandstones with flute marks and mixed sandstone–mudstone hybrid event beds mainly with groove marks, interpreted as submarine lobe-axis (or off-axis) deposits; and e) tabular, thin- to medium-bedded, fine-grained, mainly turbiditic sandstones mostly with flute marks, formed in a lobe-fringe environment. Both lobe environments also comprised turbidites with low-amplitude bed waves and large ripples, which are interpreted to represent transient-turbulent flows. The strong relationship between flute marks and turbidites agrees with earlier predictions that turbulent shear flows are essential for the formation of flute marks. Moreover, the observation as part of this study that debris-flow deposits are exclusively associated with groove marks signifies that clay-charged, laminar flows are carriers for tools that are in continuous contact with the bed. A new process model for hybrid event beds, informed by the dominance of tool marks, in particular grooves, below the basal sand division (H1 division of Haughton et al. 2009) and by the rapid change from turbidites in the channel to hybrid event beds in the channel–lobe transition zone, is proposed. This model incorporates profound erosion of clay in the channel by the head of a high-density turbidity current and subsequent transformation of the head into a debris flow following rapid lateral flow expansion at the mouth of the channel. This debris flow forms the groove marks below the H1 division in hybrid event beds. A temporal increase in cohesivity in the body of the hybrid event is used to explain the generation of the H1, H2, and H3 divisions (sensuHaughton et al. 2009) on top of the groove surfaces, involving a combination of longitudinal segregation of bedload and vertical segregation of suspension load. This study thus demonstrates that sole marks can be an integral part of sedimentological studies at different scales, well beyond their traditional use as indicators of paleoflow direction or orientation.
34
Baas, Jaco H., Niall D. Tracey e Jeff Peakall. "Sole marks reveal deep-marine depositional process and environment: Implications for flow transformation and hybrid-event-bed models". Journal of Sedimentary Research 91, n. 9 (30 settembre 2021): 986–1009. http://dx.doi.org/10.2110/jsr.2020.104.
Testo completoAbstract (sommario):
ABSTRACT Deposits of sediment gravity flows in the Aberystwyth Grits Group (Silurian, west Wales, United Kingdom) display evidence that sole marks are suitable for reconstructing depositional processes and environments in deep-marine sedimentary successions. Based on drone imagery, 3D laser scanning, high-resolution sedimentary logging, and detailed descriptions of sole marks, an outcrop 1600 m long between the villages of Aberarth and Llannon was subdivided into seven lithological units, representing: a) mudstone-poor, coarse-grained and thick-bedded submarine channel fills, dominated by the deposits of erosive high-density turbidity currents with flute marks; b) mudstone-rich levee deposits with thin-bedded, fine-grained sandstones formed by low-density turbidity currents that scoured the bed to form flute marks; c) channel–lobe transition-zone deposits, dominated by thick beds, formed by weakly erosive, coarse-grained hybrid events, with pronounced mudstone-rich or sandstone-dominated debritic divisions and groove marks below basal turbiditic divisions, and with subordinate amounts of turbidites and debris-flow deposits; d) tabular, medium- to thick-bedded turbiditic sandstones with flute marks and mixed sandstone–mudstone hybrid event beds mainly with groove marks, interpreted as submarine lobe-axis (or off-axis) deposits; and e) tabular, thin- to medium-bedded, fine-grained, mainly turbiditic sandstones mostly with flute marks, formed in a lobe-fringe environment. Both lobe environments also comprised turbidites with low-amplitude bed waves and large ripples, which are interpreted to represent transient-turbulent flows. The strong relationship between flute marks and turbidites agrees with earlier predictions that turbulent shear flows are essential for the formation of flute marks. Moreover, the observation as part of this study that debris-flow deposits are exclusively associated with groove marks signifies that clay-charged, laminar flows are carriers for tools that are in continuous contact with the bed. A new process model for hybrid event beds, informed by the dominance of tool marks, in particular grooves, below the basal sand division (H1 division of Haughton et al. 2009) and by the rapid change from turbidites in the channel to hybrid event beds in the channel–lobe transition zone, is proposed. This model incorporates profound erosion of clay in the channel by the head of a high-density turbidity current and subsequent transformation of the head into a debris flow following rapid lateral flow expansion at the mouth of the channel. This debris flow forms the groove marks below the H1 division in hybrid event beds. A temporal increase in cohesivity in the body of the hybrid event is used to explain the generation of the H1, H2, and H3 divisions (sensuHaughton et al. 2009) on top of the groove surfaces, involving a combination of longitudinal segregation of bedload and vertical segregation of suspension load. This study thus demonstrates that sole marks can be an integral part of sedimentological studies at different scales, well beyond their traditional use as indicators of paleoflow direction or orientation.
35
Lackovic, Maja, Aleksandar Damjanovic, Maja Ivkovic, Maja Pantovic, Milos Bajcetic, Branislav Rovcanin, Aleksandra Pavlovic, Nadezda Sternic e Miroslava Jasovic-Gasic. "Depression in CADASIL patients". Archives of Biological Sciences 66, n. 3 (2014): 1187–94. http://dx.doi.org/10.2298/abs1403187l.
Testo completoAbstract (sommario):
Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a hereditary neurological disease accompanied by recurrent ischemic events, characterized by the presence of psychiatric disorders. The aim of this study was to examine the occurrence of depression and its severity among patients with CADASIL. Sixteen patients with diffuse white matter changes on MRI and clinical signs suggesting CADASIL were included in the study. Definitive diagnosis of CADASIL was obtained by electron microscopic analysis of skin biopsies. Testing of the patients? affective status was primarily devoted to detecting depression. Electron microscopic examinations of all skin biopsies revealed numerous granular osmiophilic material (GOM) deposits embedded into the basal lamina around altered or degenerated vascular smooth muscle cells (VSMCs). Clinical symptoms of depression were present in a great number of examined CADASIL patients. The frequency of depression was higher than previously reported. Psychiatric disturbances might also represent the onset of CADASIL, especially in young patients, and should be evaluated by differential diagnosis.
36
Ballan-Dufrançais, C., A. Y. Jeantet, A. Geffard, J. C. Amiard e C. Amiard-Triquet. "Cellular and tissular distribution of copper in an intrasedimentary bivalve, the Baltic clam Macoma balthica, originating from a clean or a metal-rich site". Canadian Journal of Fisheries and Aquatic Sciences 58, n. 10 (1 ottobre 2001): 1964–74. http://dx.doi.org/10.1139/f01-129.
Testo completoAbstract (sommario):
Baltic clams (Macoma balthica) from clean and industrialized areas were exposed to 30 ng Cu·mL1 or 40 ng Cu·mL1 for 13 days. Specimens from the industrialized site accumulated less Cu in their soft tissues, suggesting that those clams living in a metal-rich area are able to limit metal accumulation. Cu and metallothionein-like protein (MTLP) levels were positively correlated in specimens from the industrialized site only, indicating that perhaps living in a polluted area enables them to use this method of detoxification. The contaminated specimens contained Cu-rich microgranules in the basal lamina and intracellular spaces of digestive gland, labial palps, and gills as well as in lysosomes of the digestive gland and in a few hemocytes. The coexistence of S and Cu suggests that sulfur may be the chelating agent. As a consequence of detoxified storage, ultrastructural damage was rarely observed. These Cu deposits, which contributed to the predominance of biochemical insoluble forms shown in the whole soft tissues, are generally considered hardly available to predators, whereas soluble Cu (3538% of total Cu) would most probably be bioavailable.
37
Rizzo, Vincenzo, e Nicola Cantasano. "Possible organosedimentary structures on Mars". International Journal of Astrobiology 8, n. 4 (28 agosto 2009): 267–80. http://dx.doi.org/10.1017/s1473550409990152.
Testo completoAbstract (sommario):
AbstractThis study, using the Microscopic Imager (MI) of NASA Rover Exploration Mission's (REM) ‘Opportunity’, aims to explain the origin of laminated sediments lying at Meridiani Planum of Mars, and of the strange spherules, known as blueberries, about which several hypotheses have been formulated. To this purpose, images of the sedimentary textures of layers and fragments captured by REM have been analysed; sediments that NASA has already established as ‘pertinent to water presence’. Our study shows that such laminated sediments and the spherules they contain could be organosedimentary structures, probably produced by microorganisms. The laminated structures are characterized by a sequence of a thin pair of layers, which have the features of skeletal/agglutinated laminae and whose basic constituents are made by a partition of septa and vacuoles radially arranged around a central one. The growth of these supposed organosedimentary masses is based on the ‘built flexibility’ of such a basal element; it may be a coalescing microfossil formed by progressive film accretion (calcimicrobe), in a variety of geometrical gross forms, such as a repeated couplet sequence of laminae or domal mass and large composite polycentric spherule, both in elevation. The acquired structural and textural data seem to be consistent with the existence of life on Mars and could explain an origin of sediments at Meridiani Planum similar to that of terrestrial stromatolites. The Martian deposits, probably produced by cyanobacterial activity, and the embedded blueberries could represent a recurrent and multiform product of colonies with sheath forms, resembling in shape those of the fossil genus Archaeosphaeroides (stromatolites of Fig Tree, South Africa).
38
Fernández-Robredo, Patricia, Luis M. Sádaba, Angel Salinas-Alamán, Sergio Recalde, José A. Rodríguez e Alfredo García-Layana. "Effect of Lutein and Antioxidant Supplementation on VEGF Expression, MMP-2 Activity, and Ultrastructural Alterations in Apolipoprotein E-Deficient Mouse". Oxidative Medicine and Cellular Longevity 2013 (2013): 1–11. http://dx.doi.org/10.1155/2013/213505.
Testo completoAbstract (sommario):
Oxidative stress is involved in the pathogenesis of several diseases such as atherosclerosis and age-related macular degeneration (AMD). ApoE-deficient mice (apoE−/−) are a well-established model of genetic hypercholesterolemia and develop retinal alterations similar to those found in humans with AMD. Thus supplementation with lutein or multivitamin plus lutein and glutathione complex (MV) could prevent the onset of these alterations. ApoE−/−mice (n=40, 3 months old) were treated daily for 3 months with lutein (AE-LUT) or MV (two doses): AE-MV15 (15 mg/kg/day) and AE-MV50 (50 mg/kg/day) and were compared to controls with vehicle (AE-C). Wild-type mice (n=10) were also used as control (WT-C). ApoE−/−mice showed higher retinal lipid peroxidation and increased VEGF expression and MMP-2 activity, associated with ultrastructural alterations such as basal laminar deposits, vacuoles, and an increase in Bruch's membrane thickness. While lutein alone partially prevented the alterations observed in apoE−/−mice, MV treatment substantially reduced VEGF levels and MMP-2 activity and ameliorated the retinal morphological alterations. These results suggest that oxidative stress in addition to an increased expression and activity of proangiogenic factors could participate in the onset or development of retinal alterations of apoE−/−mice. Moreover, these changes could be prevented by efficient antioxidant treatments.
39
Koski, Randolph A. "Ferromanganese deposits from the Gulf of Alaska Seamount Province: mineralogy, chemistry, and origin". Canadian Journal of Earth Sciences 25, n. 1 (1 gennaio 1988): 116–33. http://dx.doi.org/10.1139/e88-012.
Testo completoAbstract (sommario):
Ferromanganese-oxide deposits dredged from four seamounts (Welker, Miller, Murray, and Patton) in the Gulf of Alaska Seamount Province include poorly crystallized microlaminated crusts on basalt substrate, well-crystallized Mn-oxide veins in epiclastic sedimentary rocks, and crystalline Mn-oxide layers and micronodules in phosphorite. The principal rock types dredged are alkali-basalt pillow fragments and tuffaceous conglomerate and sandstone. The glassy rims of pillow fragments, the glassy goundmass of large volcanic clasts, and the tuffaceous component of the sediment are altered to palagonite. Other low-temperature alteration products include phillipsite, smectite, and carbonate-apatite.Thick (10–50 mm) Fe–Mn crusts consist mainly of δ-MnO2; straight and cuspate growth laminae indicate variable growth rates and periods of nondeposition. A larger number of detrital particles toward the top of thick crusts record the increasing influence of active volcanoes of the Aleutian arc during northwestward movement of the Pacific plate. Thick crusts on basalt substrate have higher Mn/Fe ratios and lower Co content than Fe–Mn crusts from low-latitude seamounts of the central Pacific region. Thin (< 10 mm) crusts on volcaniclastic substrate contain todorokite and birnessite and have higher Mn/Fe ratios, Ni, and Cu and lower Fe and Co than thick Gulf of Alaska crusts.Veins of todorokite and cryptomelane with complex internal structure occur in altered tuffaceous sandstone and conglomerate from Miller Seamount. Fibrous todorokite has a composition similar to those of other marine examples but may contain up to 7% Mn2+ in M2 sites. Microprobe analysis of the marine cryptomelane indicates a composition that is approximately (K,Ba)1–2(Mn4+,Co)7–8O16∙x(H2O).A third type of Fe–Mn deposit in phosphorite is an intimate mixture of todorokite (and minor δ-MnO2)-bearing layers and micronodules, carbonate-apatite, and phillipsite that encloses grains of altered volcanic glass and lithic fragments.The microlaminated structure, mineralogy (predominantly δ-MnO2), and composition (Mn/Fe ratio and transition metal, rare earth element, U, and Th contents) of the thick crusts are characteristic of hydrogenetic Fe–Mn crusts elsewhere in the Pacific. Conversely, the crystallinity and chemical composition of the Mn-oxide veins and thin crusts indicate formation during diagenesis of the volcanogenic sediment substrate. Mn and other transition metals are mobilized during low-temperature oxidative alteration (palagonitization) of basaltic volcanic glass; the oxidation of Fe2+ to Fe3+ during palagonitization and the dissolution of the dilute biogenic fraction of the sediment combine to lower the Eh of ambient pore fluid and enhance the mobility of Mn2+. Diagenesis in the phosphatic sandstone from Patton Seamount involves organic-rich sediment and pore waters elevated in phosphorus owing to upwelling above a large volcanic edifice.
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Molén, Mats O. "Field evidence suggests that the Palaeoproterozoic Gowganda Formation in Canada is non-glacial in origin". Geologos 27, n. 2 (1 agosto 2021): 73–91. http://dx.doi.org/10.2478/logos-2021-0009.
Testo completoAbstract (sommario):
Abstract During more than a century since its original identification, the Gowganda Formation in Ontario (Canada) has gradually been reinterpreted from representing mainly subglacial tillites to secondary gravity flow and glaciomarine deposits. The main pieces of geological evidence advanced in favour of glaciation in recent articles are outsized clasts that have been interpreted as dropstones and patches of diamictites in a single small-sized area at Cobalt which is still interpreted as displaying subglacial basal tillites. The present research considers field evidence in the Gowganda Formation in the light of more recent work on gravity flows linked to tectonics. Detailed studies have demonstrated that the clasts which are interpreted to be dropstones rarely penetrate laminae and are commonly draped by sediments the appearance of which is similar to lonestones in gravity flows. The “subglacial area” at Cobalt displays evidence of tectonics and gravity flows, which can be traced from the underlying bedrock, and then further in the overlying sequence of diamictites and rhythmites. The sum of geological features displays appearances at odds with a primary glaciogenic origin, and there is no unequivocal evidence present of glaciation. The data indicate deposition by non-glaciogenic gravity flows, including cohesive debris flows for the more compact units, probably triggered by tectonic displacements.
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Crino, Peter B., Barry Greenberg, John A. Martin, Virginia M. Y. Lee, William D. Hill e John Q. Trojanowski. "β-Amyloid Peptide and Amyloid Precursor Proteins in Olfactory Mucosa of Patients with Alzheimer's Disease, Parkinson's Disease, and down Syndrome". Annals of Otology, Rhinology & Laryngology 104, n. 8 (agosto 1995): 655–61. http://dx.doi.org/10.1177/000348949510400812.
Testo completoAbstract (sommario):
Dystrophic neurites are present in olfactory epithelium (OE) of patients with Alzheimer's disease (AD), Parkinson's disease (PD), and Down syndrome (DS) and occasionally in normal individuals. Cultured olfactory neuroblasts from AD patients generate carboxy terminal amyloid precursor protein (APP) fragments that contain β-amyloid (Aβ), but it is not known if deposits of Aβ and/or APP fragments occur in the OE of individuals with or without AD, PD, or DS. To determine if Aβ accumulates in the OE in situ, we probed postmortem samples of olfactory mucosa from patients with AD, PD and AD (PD/AD), and DS and AD (DS/AD), as well as from controls, using polyclonal and monoclonal antibodies to Aβ and flanking sequences in APPs. Samples of OE also were examined by thioflavin-S and electron microscopy. Labeling of Aβ was observed in 10 of 12 AD cases, 2 of 3 PD/AD cases, 3 of 4 DS/AD cases, 3 of 10 adult controls, and 4 of 6 fetal cases. The Aβ staining was seen in the basal third of the OE, in axons projecting through the lamina propria, and in metaplastic respiratory epithelium within the OE. Antibodies to other APP domains stained the OE of patients and controls. Thioflavin-S staining was present in the basal third of the OE of 8 of 9 AD patients and several PD/AD and DS/AD patients, but only in rare cells of 3 controls. Electron microscopy did not reveal amyloid fibrils in the OE. These data suggest that deposition of Aβ occurs in a variety of circumstances and is not restricted to patients with AD, PD, or DS.
42
Tan, Anna C. S., Matthew G. Pilgrim, Sarah Fearn, Sergio Bertazzo, Elena Tsolaki, Alexander P. Morrell, Miaoling Li et al. "Calcified nodules in retinal drusen are associated with disease progression in age-related macular degeneration". Science Translational Medicine 10, n. 466 (7 novembre 2018): eaat4544. http://dx.doi.org/10.1126/scitranslmed.aat4544.
Testo completoAbstract (sommario):
Drusen are lipid-, mineral-, and protein-containing extracellular deposits that accumulate between the basal lamina of the retinal pigment epithelium (RPE) and Bruch’s membrane (BrM) of the human eye. They are a defining feature of age-related macular degeneration (AMD), a common sight-threatening disease of older adults. The appearance of heterogeneous internal reflectivity within drusen (HIRD) on optical coherence tomography (OCT) images has been suggested to indicate an increased risk of progression to advanced AMD. Here, in a cohort of patients with AMD and drusen, we show that HIRD indicated an increased risk of developing advanced AMD within 1 year. Using multimodal imaging in an independent cohort, we demonstrate that progression to AMD was associated with increasing degeneration of the RPE overlying HIRD. Morphological analysis of clinically imaged cadaveric human eye samples revealed that HIRD was formed by multilobular nodules. Nanoanalytical methods showed that nodules were composed of hydroxyapatite and that they differed from spherules and BrM plaques, other refractile features also found in the retinas of patients with AMD. These findings suggest that hydroxyapatite nodules may be indicators of progression to advanced AMD and that using multimodal clinical imaging to determine the composition of macular calcifications may help to direct therapeutic strategies and outcome measures in AMD.
43
Feliciani, Claudio, Saman Mohammad Pour, Paola Toto, Giulia Coscione, Paolo Amerio e Pierluigi Amerio. "Direct Immunofluorescence Diagnosis of Pemphigus without Biopsy". Journal of Cutaneous Medicine and Surgery 2, n. 4 (aprile 1998): 209–11. http://dx.doi.org/10.1177/120347549800200406.
Testo completoAbstract (sommario):
Background: Direct immunofluorescence (DIF) is a necessary examination tool for the diagnosis of pemphigus. The suction-blister-method splits the skin at the lamina lucida and it is possible with a scalpel to separate the entire epidermis from the dermis. Objective: The study was to determine whether DIF is reliable on epidermal sheets separated using a suction apparatus. Methods: Thirteen patients were selected for this study: (nine with pemphigus vulgaris (PV), one with paraneoplastic pemphigus (PP), and three with pemphigus erythematosus (PE). Frozen epidermal sheets, separated from the dermis with a scalpel, were used as a substrate. Diagnosis with routine fluorescein isothiocyanate (FITC) antibodies was made. Results: In all patients a pericellular deposition of IgG was evident and in eight of these patients a pericellular deposition of C3 was present. In two cases of PE and one of PP, the C3 deposits were also present in the lower part of basal keratinocytes. Conclusion: This diagnostic method without skin biopsy is easy to perform and, together with the histology and clinical aspects, could be a useful tool in the diagnosis of pemphigus. We recommend this method when the patient is allergic to local anaesthetics, the patient easily produces hypertrophic scars, or in follow-up of already biopsied patients.
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Douillet, G. A., B. Taisne, È. Tsang-Hin-Sun, S. K. Müller, U. Kueppers e D. B. Dingwell. "Syn-eruptive, soft-sediment deformation of deposits from dilute pyroclastic density current: triggers from granular shear, dynamic pore pressure, ballistic impacts and shock waves". Solid Earth 6, n. 2 (21 maggio 2015): 553–72. http://dx.doi.org/10.5194/se-6-553-2015.
Testo completoAbstract (sommario):
Abstract. Soft-sediment deformation structures can provide valuable information about the conditions of parent flows, the sediment state and the surrounding environment. Here, examples of soft-sediment deformation in deposits of dilute pyroclastic density currents are documented and possible syn-eruptive triggers suggested. Outcrops from six different volcanoes have been compiled in order to provide a broad perspective on the variety of structures: Soufrière Hills (Montserrat), Tungurahua (Ecuador), Ubehebe craters (USA), Laacher See (Germany), and Tower Hill and Purrumbete lakes (both Australia). The variety of features can be classified in four groups: (1) tubular features such as pipes; (2) isolated, laterally oriented deformation such as overturned or oversteepened laminations and vortex-shaped laminae; (3) folds-and-faults structures involving thick (>30 cm) units; (4) dominantly vertical inter-penetration of two layers such as potatoids, dishes, or diapiric flame-like structures. The occurrence of degassing pipes together with basal intrusions suggest fluidization during flow stages, and can facilitate the development of other soft-sediment deformation structures. Variations from injection dikes to suction-driven, local uplifts at the base of outcrops indicate the role of dynamic pore pressure. Isolated, centimeter-scale, overturned beds with vortex forms have been interpreted to be the signature of shear instabilities occurring at the boundary of two granular media. They may represent the frozen record of granular, pseudo Kelvin–Helmholtz instabilities. Their recognition can be a diagnostic for flows with a granular basal boundary layer. Vertical inter-penetration and those folds-and-faults features related to slumps are driven by their excess weight and occur after deposition but penecontemporaneous to the eruption. The passage of shock waves emanating from the vent may also produce trains of isolated, fine-grained overturned beds that disturb the surface bedding without occurrence of a sedimentation phase in the vicinity of explosion centers. Finally, ballistic impacts can trigger unconventional sags producing local displacement or liquefaction. Based on the deformation depth, these can yield precise insights into depositional unit boundaries. Such impact structures may also be at the origin of some of the steep truncation planes visible at the base of the so-called "chute and pool" structures. Dilute pyroclastic density currents occur contemporaneously with seismogenic volcanic explosions. They can experience extremely high sedimentation rates and may flow at the border between traction, granular and fluid-escape boundary zones. They are often deposited on steep slopes and can incorporate large amounts of water and gas in the sediment. These are just some of the many possible triggers acting in a single environment, and they reveal the potential for insights into the eruptive and flow mechanisms of dilute pyroclastic density currents.
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Landowski, Michael, Una Kelly, Mikael Klingeborn, Marybeth Groelle, Jin-Dong Ding, Daniel Grigsby e Catherine Bowes Rickman. "Human complement factor H Y402H polymorphism causes an age-related macular degeneration phenotype and lipoprotein dysregulation in mice". Proceedings of the National Academy of Sciences 116, n. 9 (11 febbraio 2019): 3703–11. http://dx.doi.org/10.1073/pnas.1814014116.
Testo completoAbstract (sommario):
One of the strongest susceptibility genes for age-related macular degeneration (AMD) is complement factor H (CFH); however, its impact on AMD pathobiology remains unresolved. Here, the effect of the principal AMD-risk–associated CFH variant (Y402H) on the development and progression of age-dependent AMD-like pathologies was determined in vivo. Transgenic mice expressing equal amounts of the full-length normal human CFH Y402 (CFH-Y/0) or the AMD-risk associated CFH H402 (CFH-H/H) variant on a Cfh−/− background were aged to 90 weeks and switched from normal diet (ND) to a high fat, cholesterol-enriched (HFC) diet for 8 weeks. The resulting phenotype was compared with age-matched controls maintained on ND. Remarkably, an AMD-like phenotype consisting of vision loss, increased retinal pigmented epithelium (RPE) stress, and increased basal laminar deposits was detected only in aged CFH-H/H mice following the HFC diet. These changes were not observed in aged CFH-Y/0 mice or in younger (36- to 40-week-old) CFH mice of both genotypes fed either diet. Biochemical analyses of aged CFH mice after HFC diet revealed genotype-dependent changes in plasma and eyecup lipoproteins, but not complement activation, which correlated with the AMD-like phenotype in old CFH-H/H mice. Specifically, apolipoproteins B48 and A1 are elevated in the RPE/choroid of the aged CFH-H/H mice compared with age-matched control CFH-Y/0 fed a HFC diet. Hence, we demonstrate a functional consequence of the Y402H polymorphism in vivo, which promotes AMD-like pathology development and affects lipoprotein levels in aged mice. These findings support targeting lipoproteins as a viable therapeutic strategy for treating AMD.
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Stevenson, Christopher J., Jeff Peakall, David M. Hodgson, Daniel Bell e Aurélia Privat. "TB or not TB: banding in turbidite sandstones". Journal of Sedimentary Research 90, n. 8 (19 agosto 2020): 821–42. http://dx.doi.org/10.2110/jsr.2020.43.
Testo completoAbstract (sommario):
ABSTRACT Recognition and interpretation of sedimentary structures is fundamental to understanding sedimentary processes. Banded sandstones are an enigmatic sedimentary facies comprising alternating mud-rich (as matrix and/or mud clasts) and cleaner sand layers. The juxtaposition of hydrodynamically different grain sizes contradicts established models of cleaner-sand bedform development. Here, outcrop, subsurface core, and petrographic data from three deep-water systems, with well-constrained paleogeographic contexts, are used to describe the range of sedimentary textures, bedform morphologies, and facies associations, and to quantify the mud content of banding. Banding can occur in any part of a bed (base, middle, or top), but it typically overlies a structureless basal sandstone or mud-clast conglomerate lag, and is overlain by clean parallel-laminated sandstone and/or ripple cross-lamination. Banding morphology ranges from sub-parallel to bedforms that comprise low-angle laminae with discontinuous lenses of mudstone, or asymmetric bedforms comprising steeply dipping foresets that transition downstream into low-amplitude bedwaves, or steeply dipping ripple-like bedforms with heterolithic foresets. This style of banding is interpreted as a range of bedforms that form progressively in the upper-stage plane-bed flow regime via tractional reworking beneath mud-laden transitional plug flows. The balance of cohesive and turbulent forces, and the rate of flow deceleration (aggradation rate), govern the style of deposit. Banded sandstones and linked debrites are rarely found juxtaposed together in the same bed because they are distributed preferentially in proximal and distal settings, respectively. Understanding the origins of banding in turbidite sandstones, the conditions under which it forms, and its distribution across deep-water systems and relationship to linked debrites, is important for it to be used effectively as a tool to interpret the geological record.
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Holwerda, Femke M., Mark Evans e Jeff J. Liston. "Additional sauropod dinosaur material from the Callovian Oxford Clay Formation, Peterborough, UK: evidence for higher sauropod diversity". PeerJ 7 (14 febbraio 2019): e6404. http://dx.doi.org/10.7717/peerj.6404.
Testo completoAbstract (sommario):
Four isolated sauropod axial elements from the Oxford Clay Formation (Callovian, Middle Jurassic) of Peterborough, UK, are described. Two associated posterior dorsal vertebrae show a dorsoventrally elongated centrum and short neural arch, and nutrient or pneumatic foramina, most likely belonging to a non-neosauropod eusauropod, but showing ambiguous non-neosauropod eusauropod and neosauropod affinities. An isolated anterior caudal vertebra displays a ventral keel, a ‘shoulder’ indicating a wing-like transverse process, along with a possible prespinal lamina. This, together with an overall high complexity of the anterior caudal transverse process (ACTP) complex, indicates that this caudal could have belonged to a neosauropod. A second isolated middle-posterior caudal vertebra also shows some diagnostic features, despite the neural spine and neural arch not being preserved and the neurocentral sutures being unfused. The positioning of the neurocentral sutures on the anterior one third of the centrum indicates a middle caudal position, and the presence of faint ventrolateral crests, as well as a rhomboid anterior articulation surface, suggest neosauropod affinities. The presence of possible nutrient foramina are only tentative evidence of a neosauropod origin, as they are also found in Late Jurassic non-neosauropod eusauropods. As the caudals from the two other known sauropods from the Peterborough Oxford Clay, Cetiosauriscus stewarti and an indeterminate non-neosauropod eusauropod, do not show the features seen on either of the new elements described, both isolated caudals indicate a higher sauropod species diversity in the faunal assemblage than previously recognised. An exploratory phylogenetic analysis using characters from all four isolated elements supports a basal neosauropod placement for the anterior caudal, and a diplodocid origin for the middle caudal. The dorsal vertebrae are an unstable OTU, and therefore remain part of an indeterminate eusauropod of uncertain affinities. Together with Cetiosauriscus, and other material assigned to different sauropod groups, this study indicates the presence of a higher sauropod biodiversity in the Oxford Clay Formation than previously recognised. This study shows that it is still beneficial to examine isolated elements, as these may be indicators for higher species richness in deposits that are otherwise poor in terrestrial fauna.
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Fragiotta, Serena, Mariacristina Parravano, Riccardo Sacconi, Eliana Costanzo, Daniele De Geronimo, Francesco Prascina, Vittorio Capuano et al. "Sub-retinal pigment epithelium tubules in non-neovascular age-related macular degeneration". Scientific Reports 12, n. 1 (7 settembre 2022). http://dx.doi.org/10.1038/s41598-022-19193-6.
Testo completoAbstract (sommario):
AbstractTo describe a novel optical coherence tomography (OCT) signature resembling sub-retinal pigment epithelium (RPE) tubules (SRT) in non-neovascular age-related macular degeneration (AMD). Patients suffering from non-neovascular AMD with complete medical records and multimodal imaging were retrospectively revised in three different tertiary care centers. Multimodal imaging included color fundus photograph, spectral-domain OCT (Spectralis, Heidelberg Engineering, Germany), fundus autofluorescence, OCT angiography (RTVue XR Avanti, Optovue, Inc., Fremont, CA). A total of 7 eyes of 7 patients with drusenoid pigment epithelium detachment (PED) were consecutively analyzed. The sub-RPE tubules appeared as ovoidal structures with a hyperreflective contour and hyporeflective interior appreciable in the sub-RPE-basal lamina (BL) space on OCT B-scan. The anatomical location of the sub-RPE formations was lying above the Bruch’s membrane in 5/7 cases (71.4%) or floating in the sub-RPE-BL space in 2/7 cases (28.6%). En-face OCTA revealed a curvilinear tubulation-like structure corresponding to SRT without flow signal. Sub-RPE tubules represent a newly identified OCT signature observed in eyes with drusenoid PED. The presumed origin may include a variant of calcified structure or alternatively activated RPE cells with some residual BL or basal laminar deposits attracted to BrM for craving oxygen.
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Fragiotta, Serena, Mariacristina Parravano, Riccardo Sacconi, Eliana Costanzo, Pasquale Viggiano, Francesco Prascina, Vittorio Capuano, Eric H. Souied e Giuseppe Querques. "A common finding in foveal-sparing extensive macular atrophy with pseudodrusen (EMAP) implicates basal laminar deposits". Retina Publish Ahead of Print (21 febbraio 2022). http://dx.doi.org/10.1097/iae.0000000000003463.
Testo completo
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Aghighi, Maryam, David Chercover e Maral Rahvar. "Collision Cutaneous Neoplasms Consisting of Melanoma and Basal Cell Carcinoma". Dermatology Practical & Conceptual, 8 luglio 2021, 2021037. http://dx.doi.org/10.5826/dpc.1103a37.
Testo completoAbstract (sommario):
Collision tumors are defined as two histologically different tumor types that arise at the same anatomical location. According to the literature review performed, there are reports of 27 cases of collision tumors involving lentigo maligna melanoma (LMM) in-situ and basal cell carcinoma (BCC). In the absence of melanocytic extension beyond the lamina propria of the BCC compartment, mixed tumors are considered as melanoma in-situ colonizing the BCC, rather than invasive melanomas. We report an uncommon case of collision of BCC with LMM, two primary skin tumors that are seen in patients with significant sunlight exposure. In our case, the patient is a 91-year-old male presented with a translucent plaque with areas of brown pigmentation on his left lateral canthus. He had a history of multiple BCCs, squamous cell carcinomas and an invasive melanoma of right cheek. Given the clinical impression of BCC, the lesion was curetted. Histological examination demonstrated melanoma in-situ heavily infiltrating the dermal nodules of BCC. Deposits of melanin pigment were scattered throughout the tumor. The BCC contained about 50% atypical melanocytes. Further immunohistochemical evaluation with melanocytic and epithelial markers (melanin A, SOX-10, pan-cytokeratin and p63) confirmed the diagnosis. An unequivocal independent invasive melanoma component was not identified in this material. The collision of BCC and LMM is very rare. However, given the sun-damaged changes promote both tumors, their development at the same site, although unexpected, can be explained. Since the prognosis of the two entities is independent, wider excision to exclude invasive malignant melanoma is indicated.