Biomedical subjects

J Boya

Publications and source records attributed to J Boya.

At least 19 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↗

PubMed1996

Scientific research on the pineal gland and melatonin: a bibliometric study for the period 1966-1994.

By means of teledischarge techniques from the database MEDLINE we selected those documents that contained in their title one or several of the following descriptors: pineal*, epiphys*, or melatonin*, in addition to the descriptor pineal-body in the MESH (Medical Subject Headings) section. A total of 7,617 original documents published between 1966 and 1994 were extracted that dealt with any aspect related with the pineal gland or its main secretary product, melatonin. The main bibliometric laws were applied: Price's Law on the increase in scientific literature, Bradford's Law on the dispersion of the scientific literature, and Lotka's Law on the author's productivity. Furthermore, we have analyzed the participation index (PaI) of the main countries within the global production, the productivity index of the authors (PI), and the number of authors/paper index. Our results demonstrate an exponential increase of the scientific literature on the pineal gland ("r" value = 0.983, in contrast with a "r" value = 0.966 after the linear adjustment). The number of publications on melatonin was less than those on other aspects of pineal research until 1991, when this situation was reversed. The journal with the largest number of original papers is Journal of Pineal Research (1st Bradford's zone) with 533 articles, followed by Journal of Neural Transmission (258) and Neuroendocrinology (221), which constituted the 2nd Bradford's zone. The total number of authors is 9,140, responsible for 23,524 authorships. 3.8% of the authors present a PI > or = 1 (large producers), and 64.9% a PI = 0 (occasional authors). Lotka's Law was widely fulfilled in this material since 10.3% of the authors are responsible of 50.2% of all the papers. The average number of authors per paper has changed from 2.29 in 1966 to 3.85 in 1994. The most productive country (during the interval between 1988-1994) was USA (PaI = 30.6), followed by Japan (7.15), United Kingdom (6.45), Germany (6.37), France (6.26), Italy (6.15) and Spain (5.34). Of the total number articles published, 86.9% are in English.

Bibliometrics↗

PubMed1996

[Bibliometric evaluation of the Spanish scientific output in neurosciences. Analysis of the publication with international readership between 1984 and 1993].

A bibliometric study was made of the Spanish scientific output in the Neurosciences between 1984 and 1993. The material studied was selected in accordance with the Science Citation Index (SCI) for the year 1993 (Neurosciences section) and from the journals considered to be a "priority' by the data base Excepta Medica CD: Neurosciences. The usual bibliometric rules were used: price's law of scientific literature growth, Bradford's law of scientific literature dispersal and Lotka's law of author productivity. The national participation indices (IPa) in the leading publications with an international readership, the % SUP index (% of documents included in 10% of the world top quality production), the authors/articles index, institutional contributions and the geographical origin of these were all analyzed also. Our results showed an exponential growth in the Spanish neuroscientific literature (correlation coefficient: 0.981) and increasing IPa (period 1984-1988; 0.88; period 1989-1993: 1.59). A total of 1,488 original documents were analyzed. There was an impact factor (FI) of over 3 in 20.8% of the articles, with an average FI of 2.701. The % SUP was 6.07. The journal with the largest numbers of original papers in Brain Research (Bradford's first zone) with 186 articles and the largest IPa was in the Journal of Pineal Research (8.403). The total number of authors was 2,470, total signatures of authors were 5,958 (3.04% of the authors had a productivity index (IP) > or = 1 and 57% an IP = 0. The average number of authors/article was 4.02. The origin of the articles was: University (56.77%), Hospital (26.73%) and CSIC (14.95%). Scientific production was concentrated in the CCAA of Madrid and Cataluña 55.93%, followed by Andalucia, Castilla-León and Valencia (22.57%).

Bibliometrics↗

PubMed1995

Structure of the pineal gland in the adult cat.

The ultrastructure of the pineal gland in the adult cat is described and compared with that of other mammals. Connective tissue spaces showed capillaries with nonfenestrated endothelia and numerous unmyelinated nerve fibers. In the proximal region of the gland, myelinated nerve fibers coming from the anterior commissure were also found. Cat pinealocytes showed a nucleus with prominent nucleoli, a well developed Golgi apparatus, centrioles, granular endoplasmic reticulum, ribosomes, abundant microtubuli and enlarged mitochondria. Pinealocytes showed several long processes with bulbous endings filled with clear vesicles and scarce "synaptic" ribbons. Pineal astrocytes and their processes were characterized by the presence of abundant filaments.

Animals↗

PubMed1995

Effects of the chemical denervation on the glial cells of the rat pineal gland: an immunocytochemical study during postnatal development.

We have studied the postnatal evolution of the glial cells in the rat pineal gland after its chemical pre- and perinatal denervation, by the assessment of the immunocytochemical expression of three antigens characteristic of glial cells i.e., vimentin (VIM), glial fibrillary acidic protein (GFAP), and S-100 protein. The neurotoxic agents we applied consisted of 6-hydroxydopamine (6-OHDA) administered during the first 5 postnatal days, and N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP-4) injected to pregnant rats in the 15th gestational day. VIM immunoreactivity was detected in pineal glial cells from the first postnatal day, both in denervated and control groups. However, in denervated glands, the maturation process of the glial cells is considerably accelerated, since they appear completely detached of the connective tissue septa at day 15. From day 30, the number of VIM-positive structures progressively increases until adulthood, when a large number of immunoreactive cell processes produces a reticular appearance to the denervated pineal gland. The first GFAP and S-100 protein immunoreactive cells were observed earlier in denervated animals (5th postnatal day for S-100 protein, and 10th postnatal day for GFAP) compared with controls. In the experimentally denervated groups, the population of positive cells, as well as their size and the number of their cell processes, is considerably higher and progressively increased. They were always characteristically located in the proximal half of the gland. From day 45, this region of the gland shows a notable amount of hypertrophic positive cells with thick processes, showing a gliotic aspect.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1995

Immunocytochemical localization of basic fibroblast growth factor in the human pituitary gland.

The immunocytochemical localization of basic fibroblast growth factor (bFGF) was studied in the human pituitary gland using a polyclonal antibody against fraction 1-24 of bovine recombinant bFGF. From a technical perspective, methacarn-fixed tissues were associated with a better preservation of bFGF immunoreactivity. Basic FGF-immunopositive glandular secretory cells were detected from the fetal period to adulthood in the pars distalis. No bFGF-positive cells were found in the neural lobe, basophil invasion areas, pars tuberalis or the walls of the pituitary cleft in the fetal pituitaries where this area was available. Endothelial cells and the axons of the neurohypophysis appeared weakly immunopositive or immunonegative depending on the fixative. According to their morphology, distribution, and the serial section analysis with all the pituitary hormones and vimentin, a folliculostellate cell marker, we conclude that bFGF-positive cells appear to be somatotropes. These results are consistent with the interpretation that bFGF plays a paracrine role in the modulation of the synthesis and secretion of various pituitary hormones.

Aged↗

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↗

PubMed1993

Immunohistochemical study of the pineal glial cells in the postnatal development of the rat pineal gland.

The developmental expression of the glial antigens, vimentin (VIM), glial fibrillary acidic protein (GFAP), and S-100 protein is described in the rat pineal gland from the first postnatal day to adulthood. Thick VIM immunopositive cell cords forming a network throughout the pineal gland were observed from the first postnatal days. These cords progressively disappeared during the first postnatal month as their cells dispersed into the pineal parenchyma. From 20 to 25 postnatal days, pineal glial cells appeared as isolated star-shaped VIM immunopositive cells. Immunostaining for GFAP and S-100 protein showed a similar developmental expression pattern. Both antigens appeared later than VIM (15-20 postnatal days) and were restricted to the pineal glial cells located in the proximal third of the gland, close to the pineal stalk.

Animals↗

PubMed1993

Immunohistochemical study of the pineal astrocytes in the postnatal development of the cat and dog pineal gland.

The expression of glial antigens vimentin (VIM) and glial fibrillary acidic protein (GFAP) is described in the pineal gland of cats and dogs from the first postnatal days to adulthood. VIM immunopositive cells were observed from the first postnatal days in both species. GFAP expression starts from the second postnatal week. In adults, a notable population of stellate cells immunopositive for GFAP and VIM was found dispersed throughout the gland. According to their immunocytochemical profile, these cells could be identified as astrocytes.

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

Coexpression of vimentin and glial fibrillary acidic protein in glial cells of the adult rat pineal gland.

In the present work, coexpression of vimentin (VIM) and glial fibrillary acidic protein (GFAP) is demonstrated in the glial cells of the adult rat pineal gland. Serial consecutive Epon semithin sections (0.5 microns thick) were alternately immunostained for VIM and GFAP. GFAP positive cells and processes were found in the proximal region of the pineal gland, near the pineal stalk. Most of these cells were also immunostained for VIM in adjacent semithin sections. The significance of the coexpression VIM-GFAP and the restricted location of GFAP positive cells is discussed in relation with the maturation of pineal glial cells.

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

[The role of the pineal gland in cartesian psychophysiological doctrine].

In the present paper, we review the cartesian description of the neuromuscular reflex and the sensorial perception as well as the hypothetical role of the pineal gland on these functions. We analyze the historical bases which support the physiological cartesian doctrine and, from the perspective of our present knowledge, we evaluate the contributions of Descartes to the scientific progress of his time. In the elaborated psychophysiological theory of the french wise, the pineal gland plays a pivotal role, raising the theory that the human soul could be located within this organ.

History, 16th Century↗

PubMed1992

Immunohistochemical localization of glial fibrillary acidic protein (GFAP) in rat pineal stalk astrocytes.

In the present work, the presence and distribution of astrocytes in the rat pineal stalk is investigated applying an immunohistochemical technique for the demonstration of glial fibrillary acidic protein (GFAP) on Epon-embedded semithin sections (0.5 micron thick). GFAP-immunoreactive cells are evenly and regularly distributed along the entire pineal stalk. The GFAP-immunoreactive cells display a stellate shape showing variable numbers of cell processes that are mainly oriented parallel to the longitudinal stalk axis. Astrocytic processes show a clear tendency to encircle the remaining elements of the pineal stalk; i.e., pinealocytes, nerve fibres and blood vessels. Furthermore, glial processes form a cover layer separating the stalk from surrounding anatomical structures.

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↗