Biology of the Pineal Gland and Melatonin in Humans

Vollrath, Lutz

doi:10.1007/978-3-642-59512-7_2

Cited by 12 publications

(3 citation statements)

References 298 publications

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“…Melatonin produced in pinealocytes is released directly into the blood stream without being stored inside the cell. Recent and extensive research has revealed a variety of functions of melatonin such as its inhibitory effect on the hypothalamo-gonadal axis, oncostatic action, immuno-regulatory action, and so on [Vollrath, 2001]. On the other hand, of all the ELF-MF bioeffects, the melatonin database is most likely the largest one reported to date; thus, it provides a rich opportunity for attempting to relate the observed patterns, that is, changed or not changed melatonin level, to differences in exposure parameters.…”

Section: Introductionmentioning

confidence: 99%

Comparing performances of logistic regression and neural networks for predicting melatonin excretion patterns in the rat exposed to ELF magnetic fields

Jahandideh

Abdolmaleki

Movahedi

2009

Bioelectromagnetics

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Various studies have been reported on the bioeffects of magnetic field exposure; however, no consensus or guideline is available for experimental designs relating to exposure conditions as yet. In this study, logistic regression (LR) and artificial neural networks (ANNs) were used in order to analyze and predict the melatonin excretion patterns in the rat exposed to extremely low frequency magnetic fields (ELF-MF). Subsequently, on a database containing 33 experiments, performances of LR and ANNs were compared through resubstitution and jackknife tests. Predictor variables were more effective parameters and included frequency, polarization, exposure duration, and strength of magnetic fields. Also, five performance measures including accuracy, sensitivity, specificity, Matthew's Correlation Coefficient (MCC) and normalized percentage, better than random (S) were used to evaluate the performance of models. The LR as a conventional model obtained poor prediction performance. Nonetheless, LR distinguished the duration of magnetic fields as a statistically significant parameter. Also, horizontal polarization of magnetic fields with the highest logit coefficient (or parameter estimate) with negative sign was found to be the strongest indicator for experimental designs relating to exposure conditions. This means that each experiment with horizontal polarization of magnetic fields has a higher probability to result in "not changed melatonin level" pattern. On the other hand, ANNs, a more powerful model which has not been introduced in predicting melatonin excretion patterns in the rat exposed to ELF-MF, showed high performance measure values and higher reliability, especially obtaining 0.55 value of MCC through jackknife tests. Obtained results showed that such predictor models are promising and may play a useful role in defining guidelines for experimental designs relating to exposure conditions. In conclusion, analysis of the bioelectromagnetic data could result in finding a relationship between electromagnetic fields and different biological processes.

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Section: Introductionmentioning

confidence: 99%

Comparing performances of logistic regression and neural networks for predicting melatonin excretion patterns in the rat exposed to ELF magnetic fields

Jahandideh

Abdolmaleki

Movahedi

2009

Bioelectromagnetics

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“…Pineal parenchymal tumors originate from the melatonin-producing cells of the pineal gland and account for approximately 30% of pineal region tumors. 6 These tumors vary in histopathological features, with pineocytomas being the most benign and pineoblastomas being the most malignant. PPTID falls between these two ends of the spectrum.…”

Section: Discussionmentioning

confidence: 99%

Recurrent pineal parenchymal tumor of intermediate differentiation with intratumoral hemorrhage: A case report and review of the literature

2023

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Pineal apoplexy is a rare clinical condition. Its common symptoms include headaches, nausea, vomiting, ataxia, and gaze paralysis. These symptoms are mainly caused by obstructive hydrocephalus or direct compression of the cerebellum or midbrain. There have been no previous reports on the development of a recurrent pineal parenchymal tumor of intermediate differentiation (PPTID) with intratumoral hemorrhage. We report a case of PPTID with intratumoral hemorrhage. A 44-year-old woman developed recurrent PPTID following tumor removal and ventriculoperitoneal shunting in 2010. She visited the emergency department in April 2021 for sudden-onset dizziness and generalized weakness. Blurring of vision occurred and progressed over the previous month. Neurological examination revealed upward conjugate gaze paralysis. Brain computed tomography revealed a hyperdense lesion in the pineal region, and a recurrent tumor with hemorrhage was suspected. Magnetic resonance imaging of the brain confirmed a pineal tumor with intratumoral hemorrhage. The pineal tumor and hematoma were surgically removed via the suboccipital transtentorial approach. The patient was discharged from the hospital 2 weeks after the surgery. The pathological findings were consistent with the diagnosis of recurrent PPTID. PPTID is a rare tumor, accounting for less than 0.1% of primary central nervous system tumors. Pineal apoplexy is rare, and its incidence and clinical significance remain unclear. There have only been nine reported cases of pineal apoplexy, associated with pineal parenchymal tumors. The recurrence of PPTID with apoplectic hemorrhage after 10 years has not been reported. Despite its rarity, PPTID with apoplexy should be considered in patients with PPTID who develop sudden-onset neurological symptoms.

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“…They interpret these findings to indicate that constant light probably exerts its detrimental effects on health, tumorigenesis as well as survival via disturbances of the female reproductive cycle [6]. The mechanisms involved can be assumed to include the pineal hormone melatonin as well which as chemical signal of darkness and controlled by the central circadian clock in the N. suprachiasmatici [7] may play a very central part since it is suppressed by LL and participates in the neuroendocrine control of the female reproductive system. In addition, the authors present interesting data that disturbances in the regulation of the anti-oxidative enzymes superoxide-dismutase and catalase due to LL are also involved.…”

mentioning

confidence: 99%

Light-at-night, cancer and aging

Bartsch

2010

Aging

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Biology of the Pineal Gland and Melatonin in Humans

Cited by 12 publications

References 298 publications

Comparing performances of logistic regression and neural networks for predicting melatonin excretion patterns in the rat exposed to ELF magnetic fields

Comparing performances of logistic regression and neural networks for predicting melatonin excretion patterns in the rat exposed to ELF magnetic fields

Recurrent pineal parenchymal tumor of intermediate differentiation with intratumoral hemorrhage: A case report and review of the literature

Light-at-night, cancer and aging

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