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Artigos de revistas sobre o assunto "Pineal gland"
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Afroz, Halima, Abu Sadat Mohammad Nurunnabi, Mushfika Rahman, Nurun Nahar e Shamim Ara. "Different Shapes of The Human Pineal Gland A Study On 60 Autopsy Cases". Journal of Dhaka Medical College 23, n.º 2 (23 de outubro de 2015): 211–14. http://dx.doi.org/10.3329/jdmc.v23i2.25393.
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Context: The pineal gland has been described as an endocrine or neuroendocrine gland; however, its functions in humans are still to be defined. Different shapes of the human pineal gland have been identified. Due to its small size and different shapes recognition of this gland is much critical. Besides, due to its cellularity it may be mistaken for a neoplasm. Hence, a sound knowledge on different shapes of the pineal gland is essential for neurosurgeons, radiologists and pathologists for better diagnosis and management of pineal disorders.Methods: A descriptive study was done in the Department of Anatomy, Dhaka Medical College, Dhaka, from July 2009 to June 2010, to see the morphological shape of the human pineal gland. The present study was performed on 60 human pineal glands collected from whole human brains of unclaimed dead bodies that were under postmortem examination in the Department of Forensic Medicine, Dhaka Medical College, Dhaka. The pineal gland was collected from the brain by meticulous dissection. Then, the shape of the pineal gland was observed under the magnifying glass.Results: In the present study, pea-shaped pineal glands were found 60% in group A, 30% in group B, 5% in both group C and D, while pine cone shaped were found 25% in group A, 37.5% in group B, 25% in group C and 12.5% in group D. Besides, fusiform shaped glands were found 18.2% in group A, 63.6% in group B, 9.1% in both group C and D, where as piriform shaped found 66.7% in group B, and 16.7% in both group C and D. Moreover, cone-shaped glands were found 28.6% in group B, 57.1% in group C and 14.3% in group D.J Dhaka Medical College, Vol. 23, No.2, October, 2014, Page 211-214
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Semicheva, T. V., e A. Yu Garibashvili. "Epiphysis: current data on physiology and pathology". Problems of Endocrinology 46, n.º 4 (15 de agosto de 2000): 38–44. http://dx.doi.org/10.14341/probl11864.
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Today the pineal gland is one of the most “titled” endocrine glands, but interest in it has not diminished, but continues to increase. A Melatonin Club has been organized and operates, and Jounal of Pineal Research, Advances in Pineal Research, and European Pineal Society News are published. The rapid development of chronobiology led to the elimination of the leading role of the pineal gland and its hormone melatonin in the implementation of circadian, seasonal and annual rhythms of the most diverse functional systems of the body [1]. Despite this, the amount of modern literature in Russian, devoted not to some particular issues, but to the pineal gland and its pathology as a whole, is very limited.
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López-Figueroa, Manuel O., Jean-Paul Ravault, Bruno Cozzi e Morten M⊘ller. "Innervation of the Sheep Pineal Gland by Nonsympathetic Nerve Fibers Containing NADPH-diaphorase Activity". Journal of Histochemistry & Cytochemistry 45, n.º 8 (agosto de 1997): 1121–28. http://dx.doi.org/10.1177/002215549704500809.
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We used the NADPH-diaphorase histochemical method as a potential marker for nitric oxide synthase (NOS)-containing nerve fibers innervating the pineal gland of the sheep. Nerve fibers containing NADPH-diaphorase activity provide dense innervation of the sheep pineal gland. The nerve fibers were located in the pineal capsule, in the connective tissue septae separating the lobuli of the gland, and penetrating between the pinealo-cytes. The nerve fibers were either smooth or endowed with boutons en passant. After bilateral removal of the superior cervical ganglion, the dense network of NADPH-diaphorase-positive fibers was still present in the gland. Ganglionectomy affected neither the distribution nor the appearance of the NADPH-diaphorase-positive fibers. Most of the NADPH-diaphorase-positive fibers also contained peptide histidine isoleucine and vasoactive intestinal polypeptide, and a comparatively smaller fraction contained neuropeptide Y. Pinealocytes never exhibited NADPH-diaphorase activity. These results demonstrate a major neural input to the sheep pineal gland with NADPH-diaphorase-positive nerve fibers of nonsympathetic origin. (J Histochem Cytochem 45:1121–1128, 1997)
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Demajo, M., Olga Jozanov-Stankov e Ivana Djujic. "Content of microelements in the rat pineal gland at different ages and the effects of selenium supplementation". Archives of Biological Sciences 58, n.º 2 (2006): 69–75. http://dx.doi.org/10.2298/abs0602069d.
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The mammalian pineal gland regulates a number of important physiological processes. In this paper we report changes in the content of iron (Fe), zinc (Zn), copper (Cu), and selenium (Se) in the male rat pineal glands at 4, 5, 8, and 12 months of age. The effect of Se supplementation in drinking water on the content of pineal gland microelements was also studied. Selenium (Se)-dependent changes in pineal gland reported in this study suggest novel physicochemical and biochemical properties of Se, an important element essential in the antioxidative processes, yet known to influence a number of endocrine processes.
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Abd alsamad, M. A., A. E. Hadi, Y. J. Mohammed e M. A. Hasan. "ULTRASTRUCTURE OF PINEAL GLAND TUMOR IN WHITE RAT". IRAQI JOURNAL OF AGRICULTURAL SCIENCES 52, n.º 3 (19 de junho de 2021): 575–79. http://dx.doi.org/10.36103/ijas.v52i3.1344.
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Tumors of pineal gland are very rare brain lesion in the rats and other species like humans. Neoplasms of pineal gland should be included in the possible differential diagnosis list for brain tumor, This type happened when the tumor is sited in the pineal body region. Research scientific investigation of pineal glands of rats being of important from the scientific point view, Transmission electron microscopic study of old and young rats was done to study the pineal gland associated with aging, these changes characterized by presence of fat like droplet in cytoplasm. Furthermore in the terminal end pinealocytes which were synapsis like associated with the presence of core vesicles containing neurotransmitter like in consistency.
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Skwarlo-Sonta, Krystyna, Pawel Majewski, Magdalena Markowska, Ruslan Oblap e Bozenna Olszanska. "Bidirectional communication between the pineal gland and the immune system". Canadian Journal of Physiology and Pharmacology 81, n.º 4 (1 de abril de 2003): 342–49. http://dx.doi.org/10.1139/y03-026.
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The pineal gland is a vertebrate neuroendocrine organ converting environmental photoperiodic information into a biochemical message (melatonin) that subsequently regulates the activity of numerous target tissues after its release into the bloodstream. A phylogenetically conserved feature is increased melatonin synthesis during darkness, even though there are differences between mammals and birds in the regulation of rhythmic pinealocyte function. Membrane-bound melatonin receptors are found in many peripheral organs, including lymphoid glands and immune cells, from which melatonin receptor genes have been characterized and cloned. The expression of melatonin receptor genes within the immune system shows species and organ specificity. The pineal gland, via the rhythmical synthesis and release of melatonin, influences the development and function of the immune system, although the postreceptor signal transduction system is poorly understood. Circulating messages produced by activated immune cells are recipro cally perceived by the pineal gland and provide feedback for the regulation of pineal function. The pineal gland and the immune system are, therefore, reciprocally linked by bidirectional communication.Key words: pineal gland, melatonin, immunity, melatonin receptors, melatonin receptor transcripts.
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Rubio, A., C. Osuna, M. A. Lopez-Gonzalez, R. J. Reiter e J. M. Guerrero. "Nyctohemeral rhythmicity of type II thyroxine 5′-deiodinase activity in the pineal gland but not in the Harderian gland of the Swiss mouse". Bioscience Reports 11, n.º 2 (1 de abril de 1991): 111–17. http://dx.doi.org/10.1007/bf01119198.
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Type II thyroxine 5′-deiodinase (5′-D) activity in both pineal and Harderian glands of the Swiss mouse was studied. Pineal 5′-D activity exhibited a nyctohemeral profile with a maximal peak value at 05.00 h, which coincides with that for pineal melatonin production. However, no rhythm of 5′-D activity in the Harderian gland could be found. In pineal gland, light at night inhibited the nocturnal increase in 5′-D activity, while isoproterenol, a β-adrenergic agonist, could not stimulate the enzyme. In the Harderian gland, neither darkness, nor light at night, or isoproterenol were capable of modifying basal values of 5′-D activity.
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Barcelos, R., A. Filadelpho, S. Baroni e W. Graça. "The morphology of the pineal gland of the Magellanic penguin (Spheniscus magellanicus Forster, 1781)". Journal of Morphological Sciences 32, n.º 03 (julho de 2015): 149–56. http://dx.doi.org/10.4322/jms.081814.
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Abstract Introduction: The Magellanic Penguin migrates on the ocean currents from its reproduction colonies in Patagonia to seek abundant food on the Brazilian continental shelf. The pineal gland, an endocrine gland, whose secretions are affected by the light-darkness photoperiod, has a basic function in the biological processes of migrating animals. Melatonin, the hormone synthesized and secreted by the pineal gland affects the circadian, circannual and seasonal cycle that directly affects the migration processes of land and sea birds. Materials and Methods: Specimens were collected on the southern coast of Brazil, morphometric assessments and histological analyses of the glands were undertaken. Results: The pineal gland of the Magellanic Penguin lies in a triangular space between the brain hemispheres and the cerebellum and close to the cavernous sinus that follow the region's dura mater. The average of the pineal gland of the penguins under analysis was 11.16mm and 1,69mm for length and thickness respectively. Test t and the coefficients of co-relationship (r) between the analyzed variables demonstrated that there was no co-relationship between the morphometric variables and the size of the pineal gland (p < 0.05). The Magellanic penguin's pineal gland has a club-like sacular shape with cells in threads, involved and interlaced by fibrous conjunctive tissues. Conclusion: Results corroborated data in the literature and showed that the pineal gland of these birds is relatively greater than that of other birds and its tissue composition is similar to that of other vertebrates.
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Ashton, Anna, Jason Clark, Julia Fedo, Angelo Sementilli, Yara D. Fragoso e Peter McCaffery. "Retinoic Acid Signalling in the Pineal Gland Is Conserved across Mammalian Species and Its Transcriptional Activity Is Inhibited by Melatonin". Cells 12, n.º 2 (11 de janeiro de 2023): 286. http://dx.doi.org/10.3390/cells12020286.
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The pineal gland is integral to the circadian timing system due to its role in nightly melatonin production. Retinoic acid (RA) is a potent regulator of gene transcription and has previously been found to exhibit diurnal changes in synthesis and signalling in the rat pineal gland. This study investigated the potential for the interaction of these two systems. PCR was used to study gene expression in mouse and human pineal glands, ex-vivo organotypic cultured rat pineal gland and cell lines. The mouse and human pineal glands were both found to express the necessary components required for RA signalling. RA influences the circadian clock in the brain, therefore the short-term effect of RA on clock gene expression was determined in ex vivo rat pineal glands but was not found to rapidly regulate Per1, Per2, Bmal1, or Cry1. The interaction between RA and melatonin was also investigated and, unexpectedly, melatonin was found to suppress the induction of gene transcription by RA. This study demonstrates that pineal expression of the RA signalling system is conserved across mammalian species. There is no short-term regulation of the circadian clock but an inhibitory effect of melatonin on RA transcriptional activity was demonstrated, suggesting that there may be functional cross-talk between these systems.
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Afroz, Halima, Shamim Ara, Mushfika Rahman, Nurun Nahar, Anjuman Ara e Kanij Fatema. "Length, Breadth and Thickness of the Pineal Gland". Bangladesh Journal of Anatomy 10, n.º 2 (7 de dezembro de 2013): 63–67. http://dx.doi.org/10.3329/bja.v10i2.17286.
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Context: The pineal gland is capable of influencing or modifying the activity of the pituitary gland, islets of Langerhans, the parathyroid gland, adrenal gland and the gonads. The pineal gland through its hormone, melatonin influences many functions of the human, like circadian rhythm, mood, psychiatric disorder, sexual maturation, reproduction and aging. Melatonin, a potent antioxidant provides protection against damaging free radicals of oxygen. Various clinical problems occur due to abnormal melatonin secretion by the pineal gland. For the perfect and complete evaluation of various clinical conditions of the pineal gland, detailed morphological knowledge is essential. Study Design: Cross sectional analytical type of study. Place and period of study: Department of Anatomy, Dhaka Medical College, Dhaka from July 2009 to June 2010. Materials: 60 postmortem human pineal glands were collected from unclaimed dead bodies that were under examination in the morgue of the Department of Forensic Medicine, Dhaka Medical College Dhaka. Methods: The samples were divided into four different age groups i.e. Group-A (15-30 years), Group-B (31- 40 years), Group-C (41-50 years) and Group-D (> 50 years). Results: The mean±SD length of the pineal gland were found 8.11±0.83 mm in group A, 7.96±1.06 mm in group B, 7.51±0.55 mm in group C and 7.89±0.14 mm in group D. The mean±SD breadth of the pineal gland were found 4.39±0.34 mm in group A, 4.09±0.46 mm in group B, 4.12±0.58 mm in group C and 3.81±0.34 mm in group D. The mean±SD thickness of the pineal gland were found 2.52±0.64 mm in group A, 2.29±0.54 mm in group B, 2.14±0.32 mm in group C and 2.07±0.18 mm in group D. Conclusion: breadth and thickness of the pineal gland were found to be decreased with advancing age. DOI: http://dx.doi.org/10.3329/bja.v10i2.17286 Bangladesh Journal of Anatomy, July 2012, Vol. 10 No. 2 pp 63-67
Teses / dissertações sobre o assunto "Pineal gland"
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Van, Wyk Elizabeth Joy. "Pineal-adrenal gland interactions in search of an anti-stressogenic role for melatonin". Thesis, Rhodes University, 1993. http://hdl.handle.net/10962/d1004115.
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The multiple functions of the pineal gland have been collectively interpreted as constituting a general anti-stressogenic role. The adrenal glands play a central role in maintaining homeostasis. The major neuroendocrine consequence of long-term stress is elevated circulating glucocorticoid levels. In this study, the effect of chronic, oral hydrocortisone treatment on pineal biochemistry was investigated in male Wi star rats of the albino strain. The results show that seven days of oral hydrocortisone treatment endows the pineal gland with the ability to increase melatonin synthesis in organ culture. The increase is accompanied by a rise in NAT activity, cyclic AMP levels and enhanced specific binding to the pineal B-adrenergic receptors. It appears that hydrocortisone sensitizes the pineal gland to stimulation by B-adrenergic agonists. thus rendering the pineal more responsive to B-adrenergic agonists. Further studies were directed at demonstrating an anti-stressogenic function for the pineal gland by investigating whether the principal pineal indole, melatonin. could protect against the deleterious effects of elevated. circulating drocortisone levels. The results show that chronic, oral hydrocortisone treatment significantly increases liver tryptophan pyrrolase activity. The catabolism of tryptophan by tryptophan pyrrolase is an important determinant of tryptophan availability to the brain, and therefore, brain serotonin levels. The findings show that melatonin inhibits basal and hydrocortisone-stimulated liver tryptophan pyrrolase apoenzyme activity in a dose-dependent manner. This inhibition suggests that melatonin may protect against excessive loss of tryptophan from circulation and against deficiencies in the cerebral serotinergic system which are associated with mood and behavioural disorders. It was shown that another deleterious effect of chronic hydrocortisone treatment is a significant increase in the number of glutamate receptors in the forebrain of male Wistar rats. The increase in receptor number observed in this study is probably due to an increase in the synthesis of glutamate receptors and is associated with a marked reduction in the affinity of the glutamate receptors for glutamate. possible to demonstrate an receptor number or the For practical reasons, it was not effect of melatonin on either glutamate affinity of glutamate receptors for glutamate in rat forebrain membranes. In view of the neurotoxic effect of glutamate in the eNS, the functional significance of recently described glutamate receptors in the pineal gland was investigated. The results show that 10-4 M glutamate significantly inhibits the isoprenaline-stimulated synthesis of N-acetylserotonin and melatonin in organ culture when the pineal glands were pre-incubated with glutamate for 4 hours prior to stimulation with isoprenalin and when glutamate and isoprenaline were administered together in vitro. GABA, a glutamate metabolite could not mimic the decrease in isoprenalinestimulated melatonin, and it is likely that the observed effects were directly attributed to glutamate. Incubation of the pineal gland with 10-4 M glutamate in organ culture did not affect HIOMT activity in pineal homogenates, but significantly elevated both basal and isoprenaline-stimulated NAT activity. It was concluded that glutamate only inhibits melatonin synthesis in intact pineal glands and not in pineal homogenates. The present study has provided further support for an interaction between the pineal and the adrenal glands. There is an ever increasing likelihood that melatonin is an anti-stressogenic hormone and that the pineal gland may have a protective role to play in the pathology of stress-related diseases.
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Porter, Mark. "The role of melatonin and the pineal gland in the photoperiodic control of reproduction and smoltification in Salmonid fish". Thesis, University of Stirling, 1996. http://hdl.handle.net/1893/26676.
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The timing of seasonal events in salmonids is thought to be controlled by endogenous circannual rhythm(s) which are entrained by the seasonally-changing daylength. This thesis investigates the role of the pineal gland in the perception of the photoperiodic zeitgeber and the subsequent transmission of this information to the brain through neural or hormonal pathways. Melatonin biosynthesis by isolated rainbow trout pineal glands was shown to exhibit a differential response to graded photic or thermal stimuli. In vitro experiments were carried out at 10±0.50 C as this provided optimum melatonin levels for radioimmunoassay analysis together with a pineal longevity of up to 14 days. By incorporating a variety of light intensities into the light/dark cycle, the salmonid pineal gland was shown to synthesise significantly different levels of melatonin even when light levels varied by only 0.5 lux. Early work on the salmonid pineal suggested it was unresponsive to red light, having a spectral sensitivity which peaks between 500 and 550 nm, this study has revealed that the pineal is also capable of responding to wavelengths between 660 to 800 nm, at which pineal reception was previously thought to be severely limited. No endogenous rhythm of melatonin secretion was observed within the isolated rainbow' trout pineal gland. Both Atlantic salmon and Atlantic halibut pineals exhibited elevated levels- of melatonin in response to the dark phase, however, they also appeared capable of maintaining this rhythm in the absence of external stimuli. This provides the first evidence that the daily rhythm of melatonin production in these species is controlled by an endogenous circadian oscillator located within the pineal II gland. The pinealectomy technique developed during the course of this thesis successfully abolished the diel rhythm of melatonin secretion and, together with an enucleation procedure, enabled the pineal to be identified as the predominant source of the dark phase melatonin in Atlantic salmon and rainbow trout. However, the lateral eyes did contribute significantly to plasma melatonin levels in both species. Long term experiments, involving pinealectomy and/or implantation of melatonin, were used to investigate the role of the pineal gland in the timing of rainbow trout maturation and smoltification in Atlantic salmon. Pineal removal at the summer or winter solstices did not significantly alter the timing of smoltification. However, significantly higher blood serum osmolarities following seawater challenge tests were observed in smolts implanted with melatonin. This, together with a significant growth increase shown by salmon parr within 1 month of implantation, indicates that melatonin may directly affect the development of salmonids through either a physiological response or by influencing the entrainment of endogenous rhythms. The increased growth observed in the implanted parr is also thought to be responsible for the unimodal population distribution and high percentage of S1 smolts within this group. Investigations into the role of the pineal gland in the timing of spawning in rainbow trout found that pineal removal at the summer solstice caused a 6 week delay in spawning time compared to intact fish. However, no clear effects on spawning time were observed when pineal removal, with or without melatonin implantation, was performed to coincide with the change from long to short daylengths which is known to advance spawning times. Although no significant effect in spawning times was observed between groups, the 4 month spawning period of the pinealectomised group compared to 1 month in the shampinealectomised fish also suggested that pineal removal may have caused a desynchronisation in spawning time. Pinealectomy and/or implantation did not alter egg size or fecundity, but plasma calcium levels were shown to be significantly lower in the pinealectomised trout over the spawning period. To summarise, the pineal gland and melatonin play a significant role in salmonid development. It is suggested that melatonin can influence biological systems through a direct physiological action while the pineal gland may synchronise circannual events through the photoneuroendocrine transduction of seasonal environmental information.
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Mchunu, Bongani Isaac. "The effect of appetite suppressants on pineal function". Thesis, Rhodes University, 1994. http://hdl.handle.net/10962/d1004098.
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The pineal gland has become the subject of considerable investigation as it provides a productive experimental model for studying circadian rhythms and regulation of end organs. In the rat, the pineal gland provides a convenient model for investigating the noradrenergic receptor system and the effects of various drugs on this system. The effect of appetite suppressants on the rat pineal gland function is described. Appetite suppressants increase melatonin synthesis in organ cultures of rat pineal glands. This effect appears to be mediated by noradrenaline acting on β-adrenoceptors on the pinealocyte membrane. When β-adrenoceptors are blocked, the appetite suppressant-induced rise in melatonin synthesis is prevented. Depletion of noradrenaline in sympathetic nerve terminals also prevented the appetite suppressant-induced rise in melatonin synthesis. Activation of β-adrenoceptors is followed by a rise in N-acetyltransferase activity via a cyclic adenosine monophosphate second messenger system. The effect of appetite suppressants on the activity of liver tryptophan pyrrolase was also investigated. The activity of this enzyme is an important determinant of tryptophan availability to the brain and consequently of brain serotonin levels. The results show that appetite suppressants inhibit both holoenzyme and total enzyme activities of tryptophan pyrrolase. This finding suggests that appetite suppressants may act by inhibiting tryptophan pyrrolase activity thereby increasing brain serotonin, a phenomenon known to be associated with anorexia. There are two possible mechanisms by which appetite suppressants inhibit tryptophan pyrrolase activity. Firstly, these agents, being drugs of dependence, may increase liver NADPH concentrations which inhibit pyrrolase activity. Secondly, appetite suppressants may act on the pineal gland to stimulate melatonin synthesis. Melatonin inhibits pyrrolase activity in a dose-dependent manner. This inhibition will elevate plasma tryptophan levels which result in a rise in brain serotonin synthesis. The present study suggests a possible relationship between the pineal gland and appetite centres in the hypothalamus. Melatonin may have a direct effect on appetite centres since food restriction is associated with an increased melatonin binding in the hypothalamus. If this possible relationship can be extended, melatonin can open new possibilities for the control of food intake and consequently, of pathological obesity.
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Machado, Sanseray da Silveira Cruz. "Caracterização do eixo imune-pineal: glândula pineal como alvo para lipopolissacarídeo (LPS)". Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/41/41135/tde-06122010-100938/.
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O fator de transcrição nuclear kappa B (NFKB), central na resposta inflamatória, é constitutivamente expresso em glândulas pineais de rato. A inibição da translocação nuclear deste fator em pineais de rato por corticosterona potencia, enquanto que a inibição pela citocina fator de necrose tumoral (TNF) inibe a síntese de melatonina por inibição da transcrição da Aa-nat. Esta redução da produção noturna de melatonina está implicada em favorecer a montagem da resposta inflamatória. Embora dados da literatura sugerirem redução da produção de melatonina durante processos infecciosos, não há evidências diretas da habilidade da glândula pineal em reconhecer o lipopolissacarídeo (LPS), a endotoxina da membrana de bactérias gram-negativas. Esta dissertação investigou se a glândula pineal de ratos expressa receptores para o reconhecimento do LPS e estabeleceu possíveis mecanismos de ação desta endotoxina na glândula pineal de ratos. Nossos resultados demonstram que a glândula pineal expressa de maneira constitutiva os receptores CD14 e o TLR4. LPS induz a translocação nuclear dos dímeros p50/p50 e p50/RelA e a síntese de TNF em glândulas cultivadas. A máxima produção de TNF no meio de cultura é coincidente com a máxima expressão do receptor TNFR1 em pinealócitos. Além disso, LPS inibe a síntese de N-acetilserotonina e melatonina. Em conclusão, neste estudo, demonstramos que a pineal é alvo para o componente de bactérias gram-negativas LPS, reforçando a proposta de que esta glândula reconhece e gera respostas a moléculas que sinalizam a montagem da resposta inflamatória.Nuclear factor-kappa B (NFKB), a pivotal player in inflammatory responses, is constitutively expressed in the pineal gland. Corticosterone inhibits pineal NFKB leading to an enhancement of melatonin production, while tumor necrosis factor (TNF) leads to inhibition of Aa-nat transcription and the production of N-acetylserotonin (NAS) in cultured glands. The reduction of nocturnal melatonin surge favors the mounting of the inflammatory response. Despite these data, there is no clear evidence of the ability of the pineal gland to recognize molecules that signal infection. This study investigated whether the rat pineal gland expresses receptors for lipopolysaccharide (LPS), the endotoxin from the membranes of gram-negative bacteria, and to establish the mechanism of action of LPS. Here we show that pineal glands possesses both CD14 and toll-like receptor 4 (TLR4), membrane proteins that bind LPS and trigger the NFKB pathway. LPS induced the nuclear translocation of p50/p50 and p50/RELA dimers and the synthesis of TNF. The maximal expression of TNF in cultured glands coincides with an increase in the expression of TNF receptor 1 (TNFR1) in isolated pinealocytes. In addition, LPS inhibited the synthesis of N-acetylserotonin and melatonin. Therefore, the pineal gland transduces gram-negative endotoxin stimulation by producing TNF and inhibiting melatonin synthesis. Here we provide evidence to reinforce the idea of an immune-pineal axis, showing that the pineal gland is a constitutive player in the innate immune response.
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Vu, Hung Quoc. "Short Term Effects of External Electric Fields on Electrical Activity of the Pineal Gland in Rats". Thesis, University of North Texas, 1996. https://digital.library.unt.edu/ark:/67531/metadc277728/.
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The effects of short term exposure (5 minutes) to EEFs at relatively high dosages (10, 25, 39, kV/m) on the electrical activity in rat pineal glands was studied.
Daytime and nighttime recordings were taken from an implanted microelectrode in the gland. The data show that (1) both the activity and frequency were enhanced when the
animals were exposed to EEFs at 39 kV/m continuously and discontinuously; (2) the later condition yielded a sustained increase (36%) whereas the former a brief (10 sec) increase. This enhancement was statistically significant under both conditions (day and night). The effects observed were thought to be due to membrane alterations either in the pineal gland itself or in the neural inputs to the gland.
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Welman, Alan David. "The pineal gland as a model to elucidate the primary mode of action of sympathoactive agents". Thesis, Rhodes University, 1991. http://hdl.handle.net/10962/d1001610.
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An attempt was made to use the pineal gland as a model for the study of the primary mode of action of sympathoactive agents. Two drugs were investigated, viz. alpha-methyldopa and ephedrine whose mode of action is not entirely clear. Organ cultures of pineal glands from rats treated chronically with alpha-methyldopa showed enhanced conversion of radioactive serotonin to melatonin (aMT) , as well as its precursor Nacetylserotonin (aHT). This treatment was also found to raise Nacetyltransferase (NAT) activity. These increases associated with alpha-methyldopa treatment were further enhanced by the beta-adrenergic agonist, isoproterenol, suggesting a supersensitivity-type effect occurring at the level of the beta-receptor. A subsequent binding study, however, showed a decrease in beta-receptor binding with exposure to alpha-methyldopa, providing mitigating evidence against the occurrence of a supersensitivity phenomenon. It is possible that a metabolite of alpha-methyldopa acts as an alpha 1 and beta-adrenergic agonist, resulting in greater melatonin (aMT) and N-acetylserotonin (aHT) synthesis than by a beta-adrenergic agonist, isoproterenol. Combined treatment of pineals with alpha-methyldopa and an alphareceptor blocker, phentolamine, resulted in melatonin (aMT) , Nacetylserotonin (aHT) , and N-acetyltransferase (NAT) activity levels which were lower than those obtained with alpha-methyldopa treatment alone, thus confirming the alpha-adrenergic activity of the metabolite of alpha-methyldopa. Additional pineal metabolites were isolated and measured simultaneously in the organ culture experiments. Organ cultures of rat pineal glands treated with ephedrine showed raised levels of melatonin (aMT) and N-acetylserotonin (aHT). Treatment with ephedrine also produced raised N-acetyltransferase activity. A further enhancement of these parameters was induced by norepinephrine, suggesting a supersensitivity-type effect occurring at the level of the beta-adrenergic receptor. Rats were treated with reserpine (a norepinephrine depleter) and the pineals exposed to ephedrine. Endogenous norepinephrine normally released by the action of ephedrine was thus absent, and under these conditions, levels of melatonin (aMT) and N-acetylserotonin (aHT) were reduced. N-acetyltransferase (NAT) activity was also reduced, but maintained levels pointing to substantial adrenergic activity of ephedrine as well as norepinephrine released by virtue of the drug's action. A subsequent binding study showed a decrease in beta-adrenergic receptor binding with exposure to ephedrine and a further decrease in ephedrine treated pineals from reserpine treated rats, thus ruling out the occurrence of a supersensitivity phenomenon. It is possible that both ephedrine and released norepinephrine have alpha- and beta-receptor activity. Additional pineal metabolites were isolated and measured in the organ culture experiments. A 16-hour time profile of the production of melatonin (aMT) and N-acetylserotonin (aHT) with norepinephrine and ephedrine treatment provided useful information regarding the course of action of the two agents. A pineal cell-culture system was developed and exposed to ephedrine and norepinephrine. N-acetyltransferase (NAT) activity levels measured after exposure to these agents were raised, confirming the adrenergic activity of both in the model. Finally, an HPLC system coupled to a UV detector was used in an attempt to measure melatonin (aMT) extracted from pineal organ culture media. The results showed that melatonin could be measured by this method, however, a more sensitive detection system was recommended for future work.
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Dwyer, Virginia Michelle Gregory 1955. "A STUDY OF PINEAL GLAND POLYPEPTIDES AND PROTEINS BY POLYACRYLAMIDE GEL ISOELECTRIC FOCUSING (PAG-IEF) AND TWO-DIMENSIONAL ELECTROPHORESIS (2DE) (BRAIN REGIONS)". Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/276560.
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Eason, Jason Shane. "An investigation into cholinergic interactions in the rat pineal gland". Thesis, Rhodes University, 1993. http://hdl.handle.net/10962/d1004109.
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The mammalian pineal gland is mainly innervated by the sympathetic nervous system which modulates the activity of indole pathway enzymes and the secretion of pineal hormones. Recently researchers have demonstrated and characterized the presence of muscarinic cholinergic receptors in the pineal gland. However the role of these receptors remains unclear. In an attempt to investigate the role of cholinergic receptors in the pineal gland, a number of studies were carried out on the various steps in the indole metabolic pathway, using various agents which act on the cholinergic system. Investigations using pineal organ cultures showed that stimulation of these muscarinic cholinergic receptor sites with a parasympathomimetic agent, a rise in levels of aHT occurred without a concomitant increase in aMT levels. Further organ culture experiments using the cholinergic agonist acetylcholine and anticholinesterase agent physostigmine, produced a similar rise in aHT without altering aMT levels. This acetylcholine-induced rise in aHT levels were not altered by the ganglion blocking agent hexamethonium whilst the antimuscarinic agent atropine prevented the acetylcholine-induced rise in aHT levels. Thesefindings suggest that cholinergic agents may play a role in regulating indoleamine synthesis in the pineal gland. Cyclic-AMP assay studies showed that acetylcholine increases pineal cAMP levels significantly and does not influence the isoproterenol-induced cAMP rise in the pineal gland. The cAMP regulator cAMP-phosphodiesterase (cAMP-PDE) was found to increase significantly in the presence of the anticholinesterase agent physostigmine. NAT enzyme studies revealed that physostigmine does not affect NAT enzyme levels significantly and HIOMT studies showed that this agent does not inhibit HIOMT activity. The mechanism by which acetylcholine and physostigmine are able to cause a increase in aHT and not aMT levels needs to be researched further. Acetylcholinesterase enzyme assay studies revealed that the AChE enzyme undergoes a diurnal rhythm in the pineal gland with activity being higher during the day and lower at night. Investigations using the drug reserpine showed that this rhythm is not under the control of the sympathetic nervous system. Further research needs to be done however, in determining whether or not this enzyme is present in the pineal gland to regulate the levels of acetylcholine interacting with muscarinic receptors in the gland, or for some other reason. Choline acetyltransferase studies demonstrate the presence of the enzyme in the rat brain cerebral cortex as well as showing that melatonin increases ChAT enzyme activity in this tissue. This suggests that melatonin plays a role in cholinergic transmission there. ChAT activity could not be measured in the pineal gland however. Muscarinic receptor binding studies also carried out on rat brain cerebral cortex show that melatonin enhances cholinergic receptor affinity and receptor number in this tissue. In summary, data presented herein concur with proposals that: i) the cholinergic system affects the indole metabolic pathway by causing a rise in aRT but not aMT levels. ii) cholinergic agonist acetylcholine causes cAMP levels to rise with a concomitant increase in cAMP-PDE levels. iii) the enzyme acetylcholinesterase undergoes a diurnal rhythm in the pineal gland which is not under the control of the sympathetic nervous system. iv) the activity of the enzyme choline acetyltransferase is increased by melatonin in the rat brain cerebral cortex suggesting that melatonin facilitates cholinergic transmission in this tissue. v) melatonin enhances cholinergic receptor affinity and receptor number in the cerebral cortex of rat brain.
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Machado, Sanseray da Silveira Cruz. "Caracterização dos receptores tipo Toll em glândulas pineais de rato e sua implicação no entendimento do eixo imune-pineal". Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/41/41135/tde-30032015-093506/.
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A glândula pineal regula diversos ritmos biológicos e respostas de defesa em indivíduos hígidos através da síntese noturna de melatonina. Por outro lado, é sabido que processos inflamatórios reduzem a produção deste hormônio na glândula pineal. Neste estudo utilizamos um arranjo de qPCR para investigar a expressão circadiana de 84 genes relacionados a sinalização via receptores do tipo toll e NF-κB em glândulas pineais de rato. Confirmamos ainda, a expressão de 14 proteínas em pinealócitos através de ensaios de imunocitoquímica. Nossos resultados indicam que 70 genes inflamatórios são expressos ritmicamente na glândula pineal de ratos, enquanto 7 não são expressos e outros 7 genes são expressos, mas sem ritmicidade. Grande parte dos genes examinados apresenta padrão de expressão circadiana com maior conteúdo transcricional na fase de claro, atingindo a máxima expressão no final desta fase. Após o apagar das luzes, a expressão destes genes é rapidamente reduzida. Um possível envolvimento do ritmo de glicocorticóides endógeno sobre o padrão dessa expressão gênica foi avaliado através do bloqueio de GR por mifepristona, o que induziu a regulação da expressão de 13 genes e redução do conteúdo plasmático de melatonina no ZT18. Ainda, avaliamos o efeito da ativação dos TLR1, TLR2 e TLR6 sobre a glândula pineal e observamos que zimosan e Pam3CSK4 ativam a via do fator de transcrição NF-κB e bloqueia a síntese de melatonina induzida por noradrenalina in vitro. Por fim, utilizamos o modelo de obseidade induzido por dieta hipercalórica para avaliar se o processo inflamatório de baixa intensidade regula a síntede se melatonina in vivo. Observamos que nestas condições, a dieta hipercalórica induz rápido aumento no peso corporal e redução da produção noturna de melatonina. O efeito protetor da melatonina sobre o ganho de peso induzido por dieta foi testado através da restauração da melatonina na água de beber noturna de animais expostos à dieta. Em conjunto, nossos resultados indicam que genes inflamatórios são expressos ritmicamente na glândula pineal de ratos e influenciam a produção circadiana de melatonina via reconhecimento de padrões moleculares associados à patógenos ou sinais de perigoThe pineal gland regulates several circadian rhythms as well as immune responses in healthy animals via rhythmic production of melatonin, the hormone of darkness. On the other hand, nocturnal melatonin levels are reduced in the course of inflammation. To date, it remains to be clear the mechanisms by which the immune system affects pineal melatonin synthesis. Here we used a qPCR array profiler to investigate circadian gene expression of 84 genes related to Toll-Like Receptors and Nuclear Factor kappa B signaling. We also examined the expression of 14 proteins in pinealocytes by immunocytochemistry. Our results indicate rhythmic expression of 70 inflammatory genes, while 7 genes were not expressed and 7 were expressed without rhythmicity. The overall majority of genes tested showed a pattern of expression with a cumulative diurnal increase that peaks at the light phase of ZT12 followed by a fast reduction in the expression as soon as the light is turned off. The possible involvement of endogenous glucocorticoid rhythm in the modulation of pineal\'s inflammatory gene expression were tested by blocking Glucocorticoid Receptor (GR) using mifepristone. This procedure modulated the expression of 13 genes. In addition, the blockade of GR reduced the circulating melatonin levels at ZT18. The activation of TLR1, TLR2 and TLR6 induces the nuclear translocation of NF-κB signaling and blocks noradrenaline-induced melatonin synthesis in vitro. In addition, high-fat diet feeding increases body weight and reduce the circulating melatonin levels at ZT18. The protective role of melatonin in diet-induced weight gain was also determined by giving these rats melatonin in their drinking water at night. Altogether, our results highlight that inflammatory genes are transiently expressed in the rat pineal gland and influences the daily fluctuation of melatonin synthesis
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Burton, Susan Frances. "A study of the effects of the pineal hormone, melatonin, on dopaminergic transmission in the central nervous system of rats". Thesis, Rhodes University, 1990. http://hdl.handle.net/10962/d1001463.
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Dopamine mechanisms in the central nervous system are important in the control of both normal and abnormal motor function. The recent observations in both animal and human studies, that melatonin, the principal hormone of the pineal gland, may have a role in the control of movement and the pathophysiology of movement disorders, have given rise to the concept that melatonin may have a modulatory influence on central dopaminergic neurotransmission. This study makes use of three animal behavioural models as well as a biochemical model of central dopaminergic function to further investigate the concept. Results from studies using the biochemical model, which investigated the effect of melatonin on dopamine and apomorphine stimulation of dopamine-sensitive adenylate cylase, suggest that melatonin is neither a competitive antagonist nor agonist at the D₁ receptor level, although the possibility of physiological stimulation or antagonism is not excluded. In behavioural studies, prior melatonin mg/kg administration (1 and 10 (8M) ip) inhibited apomorphine induced stereotypy and locomotor activity in normal rats, and apomorphine-induced rotational behaviour in 6-hydroxydopamine and quinolinic acid lesioned rats. The possibility that these results may have physiological significance is borne out by the observation that, under enviromental lighting conditions that are associated with raised endogeous melatonin levels, apomorphine- induced stereotypy and locomotor activity is attenuated. The general conclusion is that melatonin has an inhibitory influence on central nervous system dopaminergic function, suggesting therefore, that the pineal gland and melatonin may have a role in the pathophysiology and treatment of movement and behavioural disorders associated with dopaminergic dysfunction
Livros sobre o assunto "Pineal gland"
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Bartsch, Christian, Hella Bartsch, David E. Blask, Daniel P. Cardinali, William J. M. Hrushesky e Dieter Mecke, eds. The Pineal Gland and Cancer. Berlin, Heidelberg: Springer Berlin Heidelberg, 2001. http://dx.doi.org/10.1007/978-3-642-59512-7.
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Arendt, J. Melatonin and the mammalian pineal gland. London: Chapman & Hall, 1995.
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J, Reiter Russel, e Karasek Michal, eds. Advances in pineal research. London: John Libbey, 1986.
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Fraschini, Franco, Russel J. Reiter e Bojidar Stankov, eds. The Pineal Gland and Its Hormones. Boston, MA: Springer US, 1995. http://dx.doi.org/10.1007/978-1-4615-1911-9.
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J, Reiter Russel, e Fraschini Franco, eds. Advances in pineal research : 2. London: John Libbet, 1987.
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J, Reiter Russel, e Karasek Michal, eds. Advances in pineal research:3. London: Libbey, 1989.
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Béla, Mess, ed. The pineal gland: Current state of pineal research : proceedings of the Third Colloquium of the European Pineal Study Group, Pécs, Hungary, August 13-17, 1984. Amsterdam: Elsevier Science Publishers, 1985.
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Foundation, Ciba, ed. Photoperiodism, melatonin and the pineal. London: Pitman, 1985.
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Derek, Gupta, e Reiter Russel J, eds. The Pineal gland during development: From fetus to adult. London: Croom Helm, 1986.
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ed, Gupta Derek, e Reiter Russel J. ed, eds. The Pineal gland during development: From fetus to adult. London: Croom Helm, 1986.
Encontre o texto completo da fonteCapítulos de livros sobre o assunto "Pineal gland"
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Reiter, Russel J., e Mary K. Vaughan. "Pineal Gland". In Endocrinology, 215–38. New York, NY: Springer New York, 1988. http://dx.doi.org/10.1007/978-1-4614-7436-4_9.
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Prayson, Richard A., e Karl M. Napekoski. "Pineal Gland Lesions". In Frozen Section Library: Central Nervous System, 131–37. New York, NY: Springer New York, 2010. http://dx.doi.org/10.1007/978-1-4419-7579-9_10.
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Lindstrom, Katherine M., e M. Beatriz S. Lopes. "The Pineal Gland". In Endocrine Pathology:, 115–30. New York, NY: Springer New York, 2009. http://dx.doi.org/10.1007/978-1-4419-1069-1_6.
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Afeche, Solange Castro, Fernanda Gaspar do Amaral e José Cipolla-Neto. "Pineal Gland Culture". In Melatonin, 95–100. New York, NY: Springer US, 2022. http://dx.doi.org/10.1007/978-1-0716-2593-4_12.
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Brumback, Roger A., e Richard W. Leech. "Pineal Gland Pathology". In Oklahoma Notes, 217–21. New York, NY: Springer New York, 1995. http://dx.doi.org/10.1007/978-1-4612-0811-2_15.
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Schiffer, Davide, Maria Teresa Giordana, Alessandro Mauro e Riccardo Soffietti. "Pineal Gland Tumors". In Brain Tumors, 275–86. Berlin, Heidelberg: Springer Berlin Heidelberg, 1997. http://dx.doi.org/10.1007/978-3-642-60529-1_14.
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Zbella, Edward A., e Norbert Gleicher. "The Pineal Gland". In Principles of Medical Therapy in Pregnancy, 269–71. Boston, MA: Springer US, 1985. http://dx.doi.org/10.1007/978-1-4613-2415-7_23.
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Narváez-Rojas, Alexis Rafael, Juan Bosco González-Torres, Ali A. Dolachee e Ali Odai Mahmood. "Embryology of the Pineal Gland". In Pineal Neurosurgery, 1–9. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-53191-1_1.
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Narváez-Rojas, Alexis Rafael, Ali A. Dolachee, Aktham O. Alkhafaji, Mustafa E. Almurayati, Mohammed Ali Al-Dhahir e Hayder R. Salih. "Anatomy of the Pineal Gland". In Pineal Neurosurgery, 11–19. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-53191-1_2.
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Narváez-Rojas, Alexis Rafael, Luis R. Moscote-Salazar, Ali A. Dolachee, Mohammed Ameen Alrawi, Ali M. Neamah e Saja A. AlBanaa. "Physiology of the Pineal Gland". In Pineal Neurosurgery, 21–29. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-53191-1_3.
Texto completo da fonteTrabalhos de conferências sobre o assunto "Pineal gland"
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Bazzi, Latifa A., Lara Sigurdardottir, Sigurdur Sigurdsson, Unnur Valdimarsdottir, Johanna Torfadottir, Thor Aspelund, Lenore Launer et al. "Abstract 5045: Pineal gland volume and risk of prostate cancer". In Proceedings: AACR Annual Meeting 2019; March 29-April 3, 2019; Atlanta, GA. American Association for Cancer Research, 2019. http://dx.doi.org/10.1158/1538-7445.sabcs18-5045.
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Bazzi, Latifa A., Lara Sigurdardottir, Sigurdur Sigurdsson, Unnur Valdimarsdottir, Johanna Torfadottir, Thor Aspelund, Lenore Launer et al. "Abstract 5045: Pineal gland volume and risk of prostate cancer". In Proceedings: AACR Annual Meeting 2019; March 29-April 3, 2019; Atlanta, GA. American Association for Cancer Research, 2019. http://dx.doi.org/10.1158/1538-7445.am2019-5045.
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Menezes, João Lucas Pordeus de, João Victor Bezerra Ramos, Louyse Jerônimo de Morais e Maurus Marques de Almeida Holanda. "Regression of Tumor in the Pineal Gland after Exclusive Radiotherapy: Case Report". In XIII Congresso Paulista de Neurologia. Zeppelini Editorial e Comunicação, 2021. http://dx.doi.org/10.5327/1516-3180.569.
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Background: Brain tumors are the most common solid neoplasia and the main cause of death from malignancy in children. Germ cell tumors (GCT) of the central nervous system (CNS) are rare. In pediatrics, the main location is close to the pineal gland and germinomas are the most common intracranial GCTs. Objectives and Methods: To describe the case of a patient with a possible germinoma treated exclusively with radiotherapy. The case was studied and came from a referral hospital – João Pesssoa, PB. Results: Reports “impaired failure”, disorientation and headache. Computed tomography: Hydrocephalus and strong tumor suspicion in the pineal region. Alpha-fetoprotein (AFP) and beta-gonadotropin (betaHCG) measurements: Normal. Treatment can be based on radiotherapy or chemotherapy followed by radiotherapy. In this case, radiotherapy was performed at a dosage of 10 Gy, with control, after one month, by means of magnetic resonance imaging that revealed regression of the lesion. The treatment corroborated the hypothesis of a germinoma, which is extremely radiosensitive. However, the regression made it impossible to perform the anatomopathological exam for diagnostic conclusion. Conclusions: It can be seen, then, that primary CNG GCTs are part of a heterogeneous group of extremely rare lesions, with germinoma therapy still controversial. The case shows regression of a possible germinoma only with the use of radiotherapy.
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Lukina, Larisa Viktorovna, Anastasiya Vitalyevna Shilova e Natalia Isaevna Ananyeva. "RISK OF DEVELOPING CENTRAL VENOUS HYPERTENSION IN PATIENTS WITH VARIOUS TYPES OF PINEAL CYST". In Themed collection of papers from Foreign intemational scientific conference «Joint innovation - joint development». Medical sciences . Part 2. Ьу НNRI «National development» in cooperation with PS of UA. June 2023. Crossref, 2023. http://dx.doi.org/10.37539/230629.2023.97.85.034.
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Pineal gland cysts are a frequent accidental finding during neuroimaging. It is assumed that non-occlusive cysts can compress the deep veins of the brain and lead to hypertension. We analyzed the MR studies of 79 people with an epiphysis cyst and, based on the calculated thalamic and lamellar-valico-cystic coefficients, determined the risk group for the development of central venous hypertension.
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Rompala, Kevin, Richard Rand e Howard Howland. "Dynamics of Three Coupled Van der Pol Oscillators With Application to Circadian Rhythms". In ASME 2005 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/detc2005-84017.
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In this work we study a system of three van der Pol oscillators, x, y and w, coupled as follows: x¨−ε(1−x2)x˙+x=εμ(w−x)y¨−ε(1−y2)y˙+y=εμ(w−y)w¨−ε(1−w2)w˙+p2w=εμ(x−w)+εμ(y−w) Here the x and y oscillators are identical, and are not directly coupled to each other, but rather are coupled via the w oscillator. We investigate the existence of the in-phase mode x = y for ε ≪ 1. To this end we use the two variable expansion perturbation method (also known as multiple scales) to obtain a slow flow, which we then analyze using the software products MACSYMA and AUTO. Our motivation for studying this system comes from the presence of circadian rhythms in the chemistry of the eyes. We model the circadian oscillator in each eye as a van der Pol oscillator (x and y). Although there is no direct connection between the two eyes, they are both connected to the brain, especially to the pineal gland, which is here represented by a third van der Pol oscillator (w).
Relatórios de organizações sobre o assunto "Pineal gland"
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Cassone, Vincent M. Melatonin, the Pineal Gland, and Circadian Rhythms. Fort Belvoir, VA: Defense Technical Information Center, fevereiro de 1994. http://dx.doi.org/10.21236/ada280467.
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Cassone, Vincent M. Melatonin, The Pineal Gland and Circadian Rhythms. Fort Belvoir, VA: Defense Technical Information Center, abril de 1992. http://dx.doi.org/10.21236/ada250640.
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Dryer, Stuart E. Electrophysiological Properties of Intrinsic Circadian Oscillators in the Chick Pineal Gland. Fort Belvoir, VA: Defense Technical Information Center, janeiro de 1997. http://dx.doi.org/10.21236/ada329751.
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Droby, Samir, Tim R. Gottwald, Richard Stange, Efraim Lewinsohn e T. Gregory McCollum. Characterization of the biochemical basis of host specificity of Penicillium digitatum and Penicillium italicum on citrus fruit. United States Department of Agriculture, maio de 2008. http://dx.doi.org/10.32747/2008.7587726.bard.
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l. This research demonstrates that citrus fruit volatiles play an important role in host recognition by P. digitatum and P. italicum. 2. Volatiles derived from non-host fruits and vegetables (apple, pear, tomato, pepper, strawberry and avocado) had no effect on promotion of spore germination and growth of citrus pathogens. 3. Citrus volatiles have a specific stimulatory effect solely on P. digitatum and P. italicum. Non-citrus pathogens such as P. expansum and B. cinerea not affected orinhibited by the volatile materials. The specific stimulatory effect of fruit peelvolatiles on citrus pathogens and inhibitory effect on non-pathogens indicateimport ant role of volatile compounds in the host selectivity of citrus postharvestpathogens. 4. Comparative CG-MS quantification was per formed and identification of volatileconstituents of citrus commercial oils, peel extracts and the headspace of thewounded fruits was completed. Monoterpenehydrocarbons (limonene, a-pinene,sabinene, and myrcene) were the most abundant in all volatiles regardless of thesource. 5. Our results demonstrated stimulation of germination and germ tube growth in both P. digitatum and P. italicum by limonene, myrcene, a-pinene, and b-pinene). Limonenewas show n to be the most efficient in induction of germination and growth in bothpathogens. 6. P. digitatum spores placed on the surface of lemon fruit, adjacent to a wounded oil gland, were induced to germinate and grow, thus supporting all the in vitro results and demonstrating that the phenomenon of stimulation of germination and growth occurs on the fruit. 7. We established that P. digitatum is capable of biotransformation of limonene to a terpineol. a-terpinel was proved to be involved in induction of fungal sporulation process. 8. Chemotropism (directional growth) of P. digitatum towards the volatiles released from the oil glands on fruit surface was demonstrated. 9. Citrus germplasm screening work for fruit susceptibility/resistance for P. digitatum infection showed no definitive results regarding host range and susceptibility.Although the sour orange selections appear to show higher resistance to infection and decay development. 10. We demonstrated that P. expansum, non citrus pathogen, is capable of germinating in citrus fruit surface wounds, but it strongly induced host resistance mechanisms which restrict it growth and prevented decay development. The host (citrus fruit) reacted strongly by production of ROS. On the other hand, P. digitatum seems to actively suppress host natural resistance mechanisms possibly through inhibiting the production of ROS production.