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Case Reports 2004; 25(3): 173-175 PubMed PMID: 15349080 Citation  Keywords:  Child, Cysts:surgery, Female, Humans, Luteinizing Hormone:blood, Pineal Gland:surgery, Puberty, Precocious:etiology,.   

: Accelerated development of secondary sexual characteristics or sexual precocity is a well-known entity. Most authors recognize two groups of patients, those described as having central precocious puberty (CPP) and those with precocious pseudopuberty. CPP results from premature activation of the hypothalamic-pituitary-gonadal axis and pseudopuberty is caused by lesions that secrete gonadotropin-like substances or hormones. The onset of CPP is usually before age 8 in females and age 9 in males; however, there is contention that the age of onset is much earlier and also differs depending on the patients' race. Previously reported causes of CPP include intracranial neoplasm, infection, trauma, hydrocephalus and Angelman's syndrome. Pineal cysts are usually asymptomatic incidental findings, but have been associated with CPP. We present an interesting case of a patient with CPP and an associated pineal cyst. We review the literature on the pathogenesis of CPP and associated pineal cyst, the neuroendocrine relationship between the pineal gland and puberty and the neurosurgical role in these cases....

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Journal Article 2004; 25(1-2): 127-134 PubMed PMID: 15159696 Citation  Keywords:  Animals, Female, Organelles:ultrastructure, Photoreceptor Cells:growth & development, Pineal Gland:cytology, Sexual Maturation:physiology, Sheep:anatomy & histology,.   

OBJECTIVE: The study was performed to analyze the ultrastructure of ovine pinealocytes during the period of postnatal development.

MATERIAL AND METHODS: The pineals of newborn, 10-week and one-year old females of the domestic sheep were prepared for ultrastructural investigations. The point count analysis was used in quantitative studies of the pinealocyte substructures.

RESULTS: The prominent feature of pinealocytes in the newborns was the presence of well developed rough endoplasmic reticulum and numerous polysomes. The pinealocyte cytoplasm contained also smooth endoplasmic reticulum, mitochondria, Golgi apparatus, lysosomes, dense core vesicles, multivesicular bodies and lipid droplets. Pinealocytes of the 10-week and 1-year old sheep were characterized by the occurrence of numerous vesicles and short cisterns of smooth endoplasmic reticulum, abundant microtubules and lipid droplets. Pinealocytes of the adult sheep were distinguished by well developed Golgi apparatus, numerous dense core vesicles and multivesicular bodies. The relative volume of rough endoplasmic reticulum in pinealocytes was significantly higher in the newborn sheep than in two other groups. The relative volume of mitochondria was significantly higher in pinealocytes of the 10-week old sheep than the newborns and one-year old animals. The relative volume of Golgi apparatus was significantly higher in the one-year old animals than in two other groups. No differences concern lysosomes. The relative volume of lipid droplets as well as the numerical density of dense core vesicles and multivesicular bodies increased significantly with age.

CONCLUSION: The ultrastructure of ovine pinealocytes undergoes the marked changes during postnatal development. The changes concern mainly substructures involved in secretory activity....

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Comparative Study 2004; 25(1-2): 115-118 PubMed PMID: 15159694 Citation  Keywords:  Animals, Atrophy:prevention & control, Male, Melatonin:physiology, Organ Size, Pineal Gland:physiology, Rats, Rats, Wistar, Thymus Gland:pathology,.   

OBJECTIVES: The purpose of this study was to investigate the effects of pinealectomy and pinealectomy plus melatonin administration on thymus weight and histology in adult Wistar-albino rats.

METHODS: The animals were divided into three groups. Group I and Group II were designated as control (sham-pinealectomized) and pinealectomized rats, respectively. They received 10% ethanol (0.1 ml per day s.c.) alone. The rats in Group III were pinealectomized and daily injected with melatonin (3 mg/kg/0.1 ml 10% ethanol per day s.c.) commencing on the day seven after surgical operation. Injections were applied for two months.

RESULTS: The thymus atrophied and its weight decreased after pinealectomy (p<0.001). The cortico-medullary boundary could not be distinguished and in the thymus induced a loss of lymphoid elements, increased number of phagocytic macrophages and enlarged blood vessels. Melatonin prevented the thymic involution.

CONCLUSIONS: These results suggest that pinealectomy decreases thymus weight and that long-term administration of melatonin restores thymus weight to normal levels....

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Comparative Study 2004; 25(1-2): 102-108 PubMed PMID: 15159692 Citation  Keywords:  Adaptation, Physiological, Animals, Circadian Rhythm:radiation effects, Darkness, Light, Male, Photoperiod, Photoreceptor Cells:radiation effects, Pineal Gland:radiation effects, Rats, Rats, Wistar,.   

OBJECTIVE: This study was aimed to examine the pineal gland of rats exposed to constant light and darkness at light and electron microscopic level.

DESIGN: For this purpose 18 male Wistar rats were used. Animals were divided into three groups. Rats in group I (Control) were kept under 12 hrs light: 12 hrs dark conditions. Rats in group II were exposed to constant darkness, while rats in group III were exposed to constant light for 6 weeks. At the end of the experiment, all animals were killed by decapitation. The pineal glands of rats were removed, then processed for light and electron microscopy.

RESULTS: In our study, extensive number of pinealocytes was observed in the structure of pineal gland of rats exposed to constant darkness and some of the observed pinealocytes were determined to contain double nucleoli. Furthermore, mitochondria and lipid droplets in the cytoplasm of pinealocytes were increased and rough endoplasmic reticulum sacs were enlarged in this group. Whereas, in rats those exposed to the constant light, a decrease in pinealocyte intensity was associated with increase in the connective tissue between parenchymal cells. Additionally, mitochondria and lipid droplets in the cytoplasm of cells were decreased.

CONCLUSIONS: It was observed that the pinealocyte cell activity of rats exposed to constant darkness was increased but decreased in rats exposed to constant light....

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Journal Article 2003; 24(6): 404-411 PubMed PMID: 15073565 Citation  Keywords:  Animals, Birds, Circadian Rhythm:physiology, Mammals, Pineal Gland:physiology,.   

: Endocrine biorhythms are classified according to the period time, as one of the most characteristic properties of biorhythms. Each endocrine organ has parallel more than one biorhythms with different period time (e. g. circadian and circannual rhythms). The time of acrophase of the biorhythms at the different endocrine organs is fairly variant. This review summarizes the rhythmic function of the THS-thyroid, gonadotrophic-gonadal and ACTH-adrenocortical systems. Pineal gland plays an integrative role in the regulation of rhythmic function of the endocrine system. The melatonin secretion of this gland also reveals conspicuous circadian and circannual rhythms both in mammals and in birds. Mammalian pineal is functional only if its peripheral sympathetic innervation from the superior cervical ganglion is intact. In contrast, melatonin secretion and its circadian rhythm is also maintained in birds under isolated conditions (explanted into an in vitro superfusion system). The 24 hours period time of melatonin circadian rhythm can not be changed by light impulses. The phases of the circadian rhythm, however, can be turned by changing the time of environmental light-dark phases. The wavelength of the artificial light used for reversal of circadian rhythm is an important factor. The development of the entrainment and synchronization of the circadian melatonin rhythm in birds is independent of the rhythmic day-night changes in environmental lighting condition. The differences in the main elements of the biological clock between mammals and birds are discussed....

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Journal Article 2003; 24(6): 392-396 PubMed PMID: 15073562 Citation  Keywords:  Animals, Circadian Rhythm, Male, Melatonin:blood, Models, Animal, Pineal Gland:secretion, Postoperative Complications:metabolism, Pressure, Rats, Rats, Sprague-Dawley, Surgical Instruments,.   

OBJECTIVES: Pineal gland hormone, melatonin, is a current issue of interest for accumulating data concerning its diverse physiological functions. The disturbances in melatonin secretion are observed in different pathological conditions involving pineal regions, but it is not ascertained if those disturbances present any clinical implications. The aim of this work was to examine whether pineal gland compression changes melatonin secretion.

SETTING AND DESIGN: The experiment was carried out on adult rats, divided into four equal groups: (i) control (no surgery was performed), (ii) sham-operated, (iii) with sham pineal gland compression and (iv) with pineal gland compression performed by cotton piece application.

METHODS: The profile of melatonin secretion was assessed in blood samples collected five times daily, every second day, starting from 8 to 14 day following surgery.

RESULTS: We found that surgery itself significantly increased night melatonin secretion in comparison to controls. By contrast, in pineal-gland compressed rats, melatonin secretion was lower than in control group, suggesting that the influence of pineal compression overcame that induced by operation stress.

CONCLUSIONS: In conclusion, we presume that pineal gland compression (like in case of some tumors) results in decrease of the concentration of blood melatonin, that may possibly result in decreased protective action of the indoleamine....

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Journal Article 2003; 24(5): 293-303 PubMed PMID: 14647000 Citation  Keywords:  Animals, Humans, Oxidative Stress:physiology, Pineal Gland:physiology, Thyroid Diseases:metabolism, Thyroid Gland:metabolism,.   

: Reactive oxygen species (ROS) play an important role in physiological processes, but - when being in excess - ROS cause oxidative damage to molecules. Under physiological conditions, the production and detoxification of ROS are more-or-less balanced. Also in the thyroid, ROS and free radicals participate in physiological and pathological processes in the gland. For example, hydrogen peroxide (H2O2) is crucial for thyroid hormone biosynthesis, acting at different steps of the process. Additionally, H2O2 is believed to participate in the Wolff-Chaikoff's effect, undergoing in conditions of iodide excess in the thyroid. Much evidence has been accumulated indicating that oxidative stress is involved in pathomechanism of thyroid disease, e.g., Graves' disease, goiter formation or thyroid cancer. Melatonin (N-acetyl-5-methoxytryptamine) - the main secretory product of the pineal gland - is a well-known antioxidant and free radical scavenger, widely distributed in the organism. Mutual relationships between the pineal gland and the thyroid have - for a long time - been a subject of intensive research. The abundant to-date's evidence relates mostly to the inhibitory action of melatonin on the thyroid growth and function and - to a lesser extent - to the stimulatory effects of thyroid hormones on the pineal gland. It is highly probable that under physiological conditions melatonin and, possibly, other antioxidants regulate ROS generation for thyroid hormone synthesis. We believe that melatonin may protect against extensive oxidative damage in the course of certain thyroid disorders or in case of a harmful action of some external factors on the thyroid. Thus, oxidative damage and the protective action of antioxidants, melatonin included, may occur during both physiological and pathological processes in the thyroid, however, this assumption, requires further studies....

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Journal Article 2003; 24(3-4): 269-273 PubMed PMID: 14523369 Citation  Keywords:  Adenocarcinoma:pathology, Animals, Cell Nucleus:ultrastructure, Circadian Rhythm:physiology, Colonic Neoplasms:pathology, Male, Mice, Mice, Inbred Strains, Neoplasm Transplantation, Organelles:ultrastructure, Pineal Gland:cytology,.   

OBJECTIVES: Relationship between the pineal gland and neoplastic disease has been repeatedly shown in many both experimental and clinical studies. However, morphological studies of the pineal gland in animals with experimentally-induced tumors are rare. Therefore, we decided to investigate the ultrastructure of pinealocytes in mice with implanted Colon 38 adenocarcinoma.

MATERIAL AND METHODS: Male adult B6D2F1 mice were used in this study. The animals were divided into two groups. Eight mice were subcutaneously implanted with Colon 38 cell suspension, whereas the other eight intact animals served as controls. Three weeks after tumor implantation four animals from each group were sacrificed by spinal cord dislocation at 12:00 h or 24:00 h. The pineal glands were removed and processed for electron microscopic studies. The cross-sectional areas of the pinealocyte and its nucleus, and relative volume of mitochondria, Golgi apparatus, lysosomes, granular endoplasmic reticulum, and lipid droplets, as well as the number of dense-core vesicles were estimated using a digital analyzer connected on-line to IBM-PC computer. Statistical analysis of the data was performed using Student's t-test and Snedecor F test.

RESULTS: In the pineal glands of the tumor-bearing animals killed during the daytime diminished size of pinealocytes and their nuclei, decreased relative volume of granular endoplasmic reticulum, lysosomes, and lipid droplets as well as decreased number of dense-core vesicles were observed. On the contrary, the relative volumes of mitochondria and Golgi apparatus were increased in these animals. In the tumor-bearing animals killed at night, however, increased cross-sectional areas of pinealocytes, and decreased number of dense-core vesicles were observed.

CONCLUSIONS: The results of our study suggest that the presence of the malignant tumor influences the morphology of pineal cells in mice. Considering the fact that different patterns of ultrastructural changes were demonstrated in pinealocytes in different tumor types in various species, it seems that the character of the ultrastructural changes observed in tumor-bearing animals depends on the animal species and tumor type....

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