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J E García-Mauriño

Publications and source records attributed to J E García-Mauriño.

15 recordsLinked to original sources
PubMed2004

Time of origin of the rat pineal gland cells. A bromodeoxyuridine immunohistochemical study.

The immunohistochemical detection of bromodeoxyuridine (BrdU) was used to study the time of origin of the cells in the pineal gland of the rat. A study was made involving 17 groups of 4 rats each, administered with a single dose of bromodeoxyuridine (BrdU, 25 mg/kg) in 7 phases of the embryonic period (E15 to E21) and in 10 postnatal phases (between P0 and P30), followed by determination in each rat of the number of visible immune-labeled cells in the pineal gland 60 days after birth. The results show that approximately 60% of the pineal cells underwent the last division(s) prior to differentiation in the prenatal period between E18 and E21. The rest of the pineal cells originated after birth, particularly in the first 5 postnatal days.

Animals↗
PubMed2000

Cell proliferation in the developing rat pineal gland. A bromodeoxyuridine immunohistochemical study.

The immunohistochemical detection of bromodeoxyuridine (BrdU) was used to study the cell proliferation in the developing rat pineal gland, from the appearance of pineal primordium in the embryonic day 15 (E15) until 30 days after birth. The results showed three different proliferative phases. From E15 to E21, the pineal gland shows a phase of rapid proliferation. The second phase corresponds to the first postnatal week, in which the number of labeled cells per surface unit decreases suddenly to values between 20% to 10% of those of embryonic period. From the second postnatal week onwards, the number of BrdU-positive cells progressively decreases.

Animals↗
PubMed1997

Influence of the light and dark phase of the cycle on the cellular proliferation in the pineal gland of the adult rat: a bromodeoxyuridine immunohistochemical study.

The cellular proliferative activity in the adult rat pineal gland was studied using bromodeoxyuridine immunohistochemistry during the light and dark phases of an artificial 12L:12D photoperiod. The results showed statistically significant differences in the number of labeled cells between the light and dark phases, with the labeled cells being almost threefold more abundant in the light period. Minor changes were also found in the pineal gland volume between both periods. The decrease in the number of labeled cells in the dark phase of the cycle could be related to the well-documented antimitotic action of melatonin.

Animals↗
PubMed1994

Immunocytochemical localization of basic fibroblast growth factor in the rat pineal gland.

The immunocytochemical localization of basic fibroblast growth factor (b-FGF) during the postnatal development of the rat pineal gland was studied using a polyclonal antibody against the fraction 1-24 of bovine recombinant b-FGF. Basic FGF immunoreactivity was evident from day 20 after birth in the endothelial cells and perivascular spaces of the gland. Although b-FGF immunostaining showed its maximal expression at 30-45 days, it was maintained throughout the entire study period (up to 6 months), mainly in the distal zone of the gland. Pinealocytes did not show b-FGF immunoreactivity at any time. There were no differences in the localization patterns or the intensity of b-FGF immunostaining after the prenatal denervation with DSP-4, a neurotoxic amine. The physiological role of b-FGF in the adult pineal gland remains unknown; however, it does not seem to play a major role during the cytodifferentiation period of the parenchymal cells, or during the neovascularization in the early postnatal days. Furthermore, its immunocytochemical expression is not affected by the prenatal sympathetic denervation with DSP-4, in contrast with other neurotropic factors.

Animals↗
PubMed1992

Immunohistochemical localization of nerve growth factor in the rat pineal gland.

Sympathetic nerve fibers arising from the superior cervical ganglia are the main innervation of the rat pineal gland. Since most organs innervated by these ganglia contain nerve growth factor (NGF), the hypothetical existence of NGF in the pineal gland was investigated. The peroxidase anti-peroxidase technique was applied for the immunohistochemical demonstration of NGF using a polyclonal antiserum on Bouin-fixed, paraffin-embedded pineal glands from adult, young and 6-hydroxydopamine (6-OHDA)-treated rats. Few immunopositive cells were observed in the adult pineal gland. A more conspicuous population of immunoreactive cells was noted in young animals (20-45 days old), especially in those chemically denervated with 6-OHDA. NGF immunoreactive cells displayed a stellate shape resembling the interstitial or glial cells previously described in the rat pineal gland. Since NGF plays a trophic effect on sympathetic neurons during development and adulthood, we postulate that its presence in the pineal gland may exert a trophic role on its sympathetic innervation.

Animals↗
PubMed1992

Postnatal development of the rabbit pineal gland. A light- and electron-microscopic study.

The development of the rabbit pineal gland has been studied by light and electron microscopy from the 1st to the 120th postnatal day. After 24 h of postnatal life, the pineal parenchyma is highly cellular, showing two identifiable cell types: pinealocytes I and II. Immature type II pinealocytes arrange either in cellular cords or clusters or forme rosette-like structures. At the 5th postnatal day, corticomedullar differentiation is established. Rosette-like structures and cellular cords are absent from the cortex. Along the postnatal period, nuclei of pinealocytes are set apart due to cytoplasmic widening and development of cell processes. These structures pervade the cellular cords and rosette-like structures formed by immature type II pinealocytes. Rosette-like structures are no longer seen beyond the 30th postnatal day, and cords of type II pinealocytes from the 90th postnatal day on. At this time, the rabbit pineal gland is considered to be histologically mature.

Animals↗
PubMed1992

Presence of melanin in the cat pineal gland.

Light- and electron-microscopic features of pigmented cells in the cat pineal gland are described. These cells were observed throughout postnatal life from the second postnatal day to the oldest cats studied (up to 13 years old). No apparent relationship was observed among the amount of pigment and the animal age or sex. Pigmented cells showed a preferential localization at the ventral surface of the pineal gland near its distal end. The pineal pigment was histochemically identified as melanin. Pineal pigment granules showed ultrastructural features similar to melanocyte melanin granules.

Animals↗
PubMed1992

Presence of melanin in normal human Schwann cells.

The presence of melanin granules in Schwann cells of unmyelinated nerve fibres in the normal skin of a black woman is demonstrated by electron microscopy. Pathological conditions associated with the differentiation ability of Schwann cells for melanogenic are reviewed. This capacity may be due to the common origin of Schwann cells and melanocytes in the neural crest.

Humans↗
PubMed1992

Postnatal maturation of the parenchymal cell types in the rabbit pineal gland.

An ultrastructural study on the maturation of the parenchymal rabbit pineal cell types from the first postnatal day up to 120 days is presented. Two main cell types are distinguished from the first 24h of postnatal life. Pinealocytes of the types I and II display different developmental degrees. Both immature cell types are arranged in groups. In addition, type II pinealocytes form rosette-like structures. Both cell types progressively become isolated and display cell processes. The nucleus and the cytoplasm of type I pinealocytes are barely electrondense. During the postnatal period, the number of cytoplasmic organelles, cell processes and terminal clubs increase progressively. Terminal clubs are frequently seen near blood vessels. After 30 days, type I pinealocytes show characteristics of adult pinealocytes. However, the maturation of most type I pinealocytes does not complete until the 90th postnatal day. Type II pinealocytes present a fairly electrondense nucleus and cytoplasm. Mature forms can be seen after the 5th postnatal day. During the postnatal period, a close relationship is determined among type II pinealocytes and cell processes and terminal clubs of type I pinealocytes.

Aging↗
PubMed1990

Postnatal development of the dog pineal gland: electron microscopy.

The ultrastructure of the dog pineal gland from the first postnatal day to the seventh month is described. In the first postnatal stages, pineal parenchyma only shows immature proliferative cells with abundant cytoplasmic glycogen. Nerve fibers are seen in the pineal connective tissue spaces. The differentiation of the dog pineal cell types begins in the first postnatal week. Both pinealocytes and pigmented cells are first seen on the fourth postnatal day. The pineal astrocytes are observed on the tenth day. Immature cells are still found in the pineal gland of 1 mo-old dogs. The differentiation of the dog pineal cell types is completed by the second postnatal month.

Animals↗
PubMed1990

Ultrastructural changes in the rat pineal gland after sympathetic denervation. Quantitative study.

Ultrastructural changes in the rat pineal gland were studied quantitatively 7 and 60 days after the sympathetic denervation by bilateral excission or decentralization of superior cervical ganglia. The surface occupied by pineal parenchymal cells decreased in rats of experimental groups with respect to the control group. Furthermore, profile areas of the cytoplasm, nucleus and nucleolus of the pinealocytes were also diminished. Cytoplasmic lipid droplets in the pinealocytes were markedly decreased in number and size in experimental rats. As demonstrated by the Kruskal-Wallis H test, statistically significant differences were found between rats of the control and operated groups. Rats treated by superior cervical ganglionectomy or decentralization showed morphological changes indicating a hypofunctional pineal gland, although differences were found between both groups.

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