In vitro effects of estradiol on pituitary GH-immunoreactive cells

In order to determine whether estradiol modulates the proliferation and activity of somatotrophic cells in vitro, a study of GH-immunoreactive cells was carried out in pituitary monolayer cultures obtained from male adult rats treated with 10(-6)M estradiol for 3 hours. Cellular activity was evaluated in a morphometric study of GH-immunoreactive cells. The proliferation rate was determined by double immunostaining for GH and PCNA (proliferating cellular nuclear antigen). The results were compared to those obtained from control dishes. Estradiol was seen to increase the cellular (p < 0.05), nuclear (p < 0.01) and cytoplasmic areas (p < 0.05). Estradiol decreased the percentage of proliferating GH-immunoreactive cells (p < 0.05) and the nuclear density of somatotrophs (p < 0.05) when all cells present in the dishes were considered. However, when only GH-immunoreactive cells were considered, estradiol increased the proliferation rate of these cells (p < 0.05). Overall, our results suggest that, in vitro, estradiol stimulates the cellular activity and proliferation of GH-immunoreactive cells in the rat.

Decreases in the size and proliferation rate of VIP-immunoreactive cells induced in vitro by testosterone are associated with decreases in VIP release

As in vitro study was carried out to determine whether testosterone directly inhibits the secretion of pituitary vasoactive intestinal peptide (VIP). A study was also conducted to elucidate the repercussions of treatment with 10(-6) M testosterone of monolayer cultures in the size and proliferation rate of pituitary VIP-immunoreactive cells, using double immunocytochemical labelling for proliferating cell nuclear antigen (PCNA) and VIP. Testosterone decreased the in vitro release of VIP from pituitary cells. It also decreased the percentage of pituitary VIP-immunoreactive and PCNA- and VIP-immunoreactive cells and decreased the size of the cellular and nuclear areas of these cells. Our results suggest that the inhibition of pituitary VIP secretion induced by testosterone could be exerted at pituitary level and that testosterone could act as a modulator of the proliferation rate of rat pituitary VIP-immunoreactive cells.

NADPH-diaphorase activity and vasopressin in the paraventricular nucleus of the hypothalamus following adrenalectomy

In order to investigate novel neuroendocrine functions of the nitric oxide synthesizing enzyme a combined histochemical and immunocytochemical study focused on the paraventricular nucleus of the hypothalamus was conducted to check a possible influence of bilateral adrenalectomy on three different neuronal populations, NADPH diaphorase (ND)-positive, vasopressin (VP)-immunoreactive and neurons expressing both markers. In the adrenalectomized animals, a slight increase (P > 0.05) of the number of ND magnocellular neurons was detected, whereas no changes were observed in the ND-parvicellular population and in the neurons showing coexistence (magno- and parvicellular) (P > 0.05). By contrast, following bilateral adrenalectomy, a significant increase (P < 0.05) in the VP-parvicellular population (anterior, medial and periventricular subdivisions) was detected, which was reversed when the animals received daily doses of corticosterone. These results suggest that nitric oxide is not closely related to the hypothalamic regulation of the adenocorticotropin secretion exerted by the paraventricular nucleus.

Morphometric evidence of the regulation of the activity of LH-immunoreactive cells by corticosterone. An in vivo and in vitro study

The present study was performed to investigate the morphometric effects of the administration of corticosterone on LH-immunoreactive cells of pituitary monolayer cultures. In addition, the effect of bilateral adrenalectomy on the LH-adenohypophyseal cells was explored. In vitro administration of corticosterone induced a marked decrease in the morphometric parameters considered (cellular, cytoplasmic and nuclear areas). In vivo, bilateral adrenalectomy produced a significant increase in these parameters when compared to those obtained in normal and sham-operated animals. However, when the bilaterally adrenalectomized rats received a daily dose of corticosterone no significant changes in the morphometric parameters were found. Morphometrically, these combined in vivo-in vitro findings confirm a corticosterone-induced hypoactivity of LH-cells together with a direct effect of this glucocorticoid on LH-adenohypophyseal cells.

Dopamine inhibits in vitro release of VIP and proliferation of VIP-immunoreactive pituitary cells

A double immunohistochemical study for VIP and proliferating cell nuclear antigen (PCNA) was carried out on monolayer cultures from adult male rats pituitary glands treated with dopamine (ranging from 10(-9) to 10(-5) M), in order to establish whether or not dopamine is involved in the regulation of the proliferation rate of pituitary VIP-immunoreactive cells. For all doses of dopamine assayed, the release of VIP to the culture medium, the numerical density of VIP-immunoreactive cells and the percentages of VIP- and PCNA-immunoreactive cells decreased significantly after dopamine treatment. These results suggest that dopamine could be a physiological inhibitor involved in the modulation of pituitary VIP proliferation rate.

In vitro morphometric and proliferative variations in VIP-immunoreactive pituitary cells induced by estradiol

Using double labelling for proliferating cell nuclear antigen (PCNA) and vasoactive intestinal peptide (VIP), a study was conducted to elucidate the repercussions of the addition of estradiol to monolayer pituitary cultures on the morphology, size, number, mitotic index and PCNA labelling index of VIP-immunoreactive cells, comparing the results with those obtained in control cultures. The addition of estradiol (100 nM) over 3 h of incubation led to a significant increase (p < 0.01) in the cellular, cytoplasmic and nuclear areas of VIP-immunoreactive cells and in the number of these cells. The same treatment elicited an even greater increase in the mitotic index (p < 0.01) and PCNA labelling index (p < 0.01) of VIP-immunoreactive cells. The results obtained suggest that estrogens induce proliferation and hyperplasia of in vitro VIP-immunoreactive pituitary cells.

Dog neutrophil stimulation and cell surface expression of heat shock proteins induced by AHN 086

The effect of AHN 086 [1-(2-isothiocyanatoethyl)-7-chloro-1,3-dihydro-5-(4- chloro-phenyl)-2H-1,4-benzodiazepine-2-one hydrochloride], an irreversible ligand of the mitochondrial benzodiazepine receptor, was studied in the heat shock protein (HSP) expression and the activation of dog neutrophils. At micromolar concentrations, AHN 086 induced a dose-dependent increase in free radical production (309 +/- 13% at 1 x 10(-5) M). This compound also increased the phagocytic activity (73 +/- 3.5% at 5 x 10(-6) M). Immunohistochemical results showed that AHN 086 induced the expression of HSP in neutrophil membranes. At 1 x 10(-5) M, the percentage of positive cells was: 90.2 (27 kD), 90.6 (72 kD) and 92.8 (90 kD). This expression was accompanied by a decrease in the presence of nuclear and cytoplasmic HSP. Flow cytometry studies showed that this cell membrane expression was located on the neutrophil surface and could be a consequence of HSP mobilization from nucleus and cytoplasm.

Effect of antihypertensive treatment on the increased beta 2-adrenoceptor density in patients with essential hypertension

The effect of different antihypertensive drugs on the increased surface beta 2-adrenoceptor density in essential hypertension was evaluated to elucidate whether the possible effect of the treatment on these receptors was secondary to blood pressure decreases or a specific effect of the drugs. Thirty-nine untreated essential hypertensive patients and 28 normotensive control subjects were studied in basal conditions. Hypertensive patients were randomly assigned to three treatment groups: bisoprolol (10 mg/day, n = 15), enalapril (20 mg/day, n = 12), and verapamil SR (240 mg/day, n = 12), and were studied before and after 1 month of treatment. Plasma catecholamines were determined by a radioenzymatic assay. Surface beta 2-adrenoceptors were measured in intact lymphocytes by radioligand binding assay using the hydrophilic ligand [3H]-CGP12177. beta 2-adrenoceptor density was increased in hypertensive patients (P < .01). After treatment, mean blood pressure decreased similarly in the three groups, while plasma catecholamines showed no significant changes in any group. beta 2-adrenoceptor number decreased only in bisoprolol-treated patients (P < .05). Mean blood pressure decreases correlated with beta 2-adrenoceptor decrements only in bisoprolol-treated patients (r = 0.65, P < .05). beta 2-adrenoceptor density correlated with plasma epinephrine levels in the control group (r = -0.50, P < .01), but not in hypertensive patients before treatment. This correlation was also observed in hypertensive patients treated with bisoprolol (r = -0.52, P < .05), but not in those treated with verapamil or enalapril. Our results suggest that bisoprolol treatment reduces the increased surface beta 2-adrenoceptor density and restores its regulation by epinephrine in essential hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenalectomy increases the glial fibrillary acidic immunoreactive-elements in the ventricular ependyma and adjacent neuropil of the rat third ventricle

The reactions of bilateral adrenalectomy (14 days) on the rat glial fibrillary acidic-immunoreactive elements of the third ventricular ependyma and adjacent neuropil were analyzed using histological, immunohistochemical and morphometric methods. Bilateral adrenalectomy led to a drastic increase in the number of immunoreactive elements located in the neuropil adjacent to the third ventricle and the optic chiasm when compared to normal and sham-operated animals (p < 0.05). By contrast, the adrenalectomized animals receiving corticosterone showed the same characteristics and morphometric values as those found in normal and sham-operated animals. The results show that the participation of the adrenal gland in astroglial responses should be taken into account.

[Pleural empyema caused by Corynebacterium sp]

Until recently Corynebacterium sp. had been considered an infrequent cause of infection in humans. In the last few years, however, it has proven its ability to produce severe pulmonary and extrapulmonary infections, generally in immunodeficient hosts. We present a rare case of an immunocompetent man 68 years-old who developed community-acquired pneumonia and left pleural empyema, with Corynebacterium sp. isolated in pleural liquid. Response to thoracic drainage and antibiotic therapy (imipenem and clindamycin) was good.

In vitro modifications in the proliferation rate of prolactin cells are accompanied by nuclear morphometric variations

In order to establish the correlation between in vitro proliferation rate and morphometric variations of prolactin immunoreactive cells, a morphometric study was carried out in rat pituitary monolayer cultures by means of the double immunocytochemical staining methods employing mouse monoclonal antiproliferative cell nuclear antigen (PCNA) and rabbit anti-prolactin (PRL) as primary antibodies. PCNA was found to be an adequate marker for proliferation in pituitary monolayer cultures. 48.35 +/- 2.78% of the cells present in the culture were in active cell cycle after 3 days of incubation and a similar proportion, 54.93 +/- 2.83% was found after 7 days. On the 3rd day, PRL immunopositive cells accounted for 15.16 +/- 0.21% of the total cellular content in the dishes and 8.68 +/- 0.12% of the PCNA immunoreactive cells were also PRL immunopositive cells and, 60.95 +/- 2.65% of PRL cells stained for PRL and PCNA. On the 7th day, an increase to 32.18 +/- 0.60% of PRL cells was found; the PCNA and PRL cells accounted for 60.32 +/- 2.34% of the total PRL cells, and 19.88 +/- 1.09% of the PCNA reactive cells stained for PRL. Additionally, the morphometric analysis performed after 3 or 7 days of incubation showed that, while the size of PRL cells remained unmodified, the nuclear area had increased on the 7th day in relation to the 3rd day (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Morphological findings of an interrelationship among the neurosecretory axons of the neural lobe of the hypophysis

In order to establish whether osmotic stimuli induce variations in the contact regions among neurosecretory axons of the neural lobe of the hypophysis, adult Sprague-Dawley rats of both sexes were treated with furosemide, a diuretic drug. Contacts between adjacent membranes with no condensations of the axolemma but increase in their osmiophilia were observed. After treatment with furosemide interaxonal contacts were significantly increased (p < 0.01, in relation to control animals). Additionally, following treatment with furosemide, axo-axonic synapses among the axons of the neural lobe were found. These findings suggest the existence of interactions among activated neurosecretory axons of the neural lobe of the adult rat.

Changes in the neurosecretory axons of the neural lobe of the hypophysis of rats treated with met-enkephalin. An ultrastructural study

Following administration of met-enkephalin into the third ventricle of rats of both sexes, an ultrastructural-morphometric study was carried out of the neural lobe of the hypophysis, comparing the results with those obtained in untreated animals, controls (injected intraventricularly with distilled water) and animals previously receiving naloxone intraperitoneally. In the untreated and control animals, both males and females, there was a high percentage (about 70%) of neurosecretory axons considered to have a normal morphology; after met-enkephalin administration, this percentage decreased and was accompanied by a rise (slightly more pronounced in the females) in the percentage of degranulated axons and a slight rise in axons with a morphology indicative of regenerative and degenerative phases. Previous administration of the opiate antagonist naloxone led to a rise in the number of axons in the degenerative phase with respect to the other groups of animals; this occurred in both sexes.

Repercussion of craniopharyngioma on the morphology of the rostral wall of the III ventricle. A combined TEM and SEM study

Using a combined scanning and electron microscope technique, the repercussion on the rostral wall of the III ventricle in a patient affected with a retrochiasmatic craniopharyngioma with growth in the ventricular direction were analysed. The apical surface of the ependymocytes was found to be free of cilia, although there were numerous microvilli. The most striking finding appreciated with the scanning electron microscope was the presence of bulbous protrusions towards the lumen of the ventricle; these were formed of cells with shapes, sizes and surface characteristics different from the rest of the ependyma, which appeared flattened. The ultrastructural study revealed the presence of large numbers of filaments and junction complexes both in the ependymal and subependymal cells. Additionally, the protruded zones corresponded to areas showing different degrees of cellular disorganization.

In vitro and in vivo evidence for direct dopaminergic inhibition of VIP-immunoreactive pituitary cells

In order to establish whether dopamine is involved in the regulation of immunocytochemical expression of VIP in pituitary cells, in vivo and in vitro studies were carried out on male rats after treatment with haloperidol and dopamine, respectively. In the in vivo studies, following intraventricular (third ventricle) administration of haloperidol, an increase in the total number of VIP-immunoreactive cells (p < 0.05) was observed; additionally, the cellular, cytoplasmic and nuclear areas were increased (p < 0.01). The in vitro studies demonstrated that dopamine induces a significant decrease (p < 0.05) in the total number of VIP-immunoreactive cells, which were smaller than the cells from the control dishes, because dopamine induces a significant decrease in their cellular, cytoplasmic and nuclear areas (p < 0.01). These results support the hypothesis that dopamine is a physiological inhibitor of pituitary VIP expression and suggest that dopamine modulates the auto- or paracrine effects of VIP in the rat pituitary.

Consumption of methane by soils

Measurements of the methane flux and methane concentration profiles in soil air are presented. The flux of methane from the soil is calculated by two methods: a) Direct by placing a static open chamber at the soil surface. b) Indirect, using the (222)Rn concentrations profile and the (222)Rn flux in the soil surface in parallel with the methane concentration ((222)Rn calibrated fluxes). The methane flux has been determined in two kinds of soils (sandy and loamy) in the surroundings of Málaga (SPAIN). The directly measured methane fluxes at all investigated sites is higher than methane fluxes derived from "Rn calibrated fluxes". Atmospheric methane is consumed by soils, mean direct flux to the atmosphere were - 0.33 g m(-2)yr-1. The direct methane flux is the same within the measuring error in sandy and loamy soils. The influence of the soil parameters on the methane flux indicates that microbial decomposition of methane is primarily controlled by the transport of methane.

Immunohistochemical-morphometric study of the LH-adenohypophyseal cells following chronic treatment with met-enkephalin

In order to test the possible effect of chronic treatment with met-enkephalin upon the LH-adenohypophyseal cells, an immunohistochemical-morphometric study was carried out in rats of both sexes receiving a daily dose of 40 micrograms of met-enkephalin intramuscularly over 15 days. Following the administration of the opioid, a drastic decrease in the cellular, cytoplasmic and nuclear areas when compared to the normal and control animals was detected. Morphologically, the main finding in males was the appearance of irregularly-shaped pseudovacuolated cells. On the other hand, in females a decrease in the intensity of reaction was found. These results strongly suggest a decrease in the activity of the LH-adenohypophyseal cells following chronic administration of met-enkephalin.

Morphometric analysis of the hypoactivity of FSH-immunoreactive cells in estrogen-primed male rats

In order to evaluate the repercussions of estradiol treatment on the morphology and activity of FSH-producing cells, an immunocytochemical and morphometric study was carried out in male rats treated chronically with estradiol, relating those findings to serum FSH levels at the time of sacrifice. Chronic administration of estradiol led to a decrease (p < 0.01) in serum hormone levels that was accompanied by a marked decrease in cellular size (p < 0.01) due to a decrease in nuclear and cytoplasmic area. Our findings suggest for the adult male rat an inhibitory effect on the synthesis and release of FSH following testicular atrophy induced by treatment with estradiol.

Combined TEM and SEM analysis of the rostral wall of the human III ventricle

A combined morphological study using transmission and scanning electron microscopy was carried out on the central zone of the rostral wall of the III ventricle from a sample taken during the operation of a patient with a retrochiasmatic craniopharyngioma. Under the scanning electron microscope, the apical cell wall of the ependymocytes generally appeared folded and lack in cilia, but with numerous microvilli developed to different extents. The flat surface cells were scarce and were polygonal in shape and limited by 3-7 prominent edges. Ultrastructural analysis revealed the existence of several types of ependymocytes and subependymal epithelial cells arranged in different layers; in both layers the presence of abundant neurofilaments and intercellular junctions was striking.

Ultrastructural and morphometric changes in somatotropic cells following intraventricular administration of Met-enkephalin to rats

An ultrastructural and morphometric study of Kurosumi et al. (1986) on type 1 GH cells in adult Sprague-Dawley rats, after the intraventricular administration of Met-enkephalin, with or without prior intraperitoneal administration of naloxone, was carried out and then compared to the same cellular type of untreated animals and of animals intraventricularly treated with distilled water, used as controls. The study demonstrated an increase of cellular (p < 0.05) and nuclear (p < 0.05) areas, an enlargement and dilation of the cisternae of the Golgi complex, with an increase in the Golgi area (p < 0.01) and the immature granules (p < 0.01); a greater development of the rough endoplasmic reticulum and an increase in the number of exocytosis (p < 0.01) and, only in male rats, an increase in the mature secretory granules (p < 0.01). The prior administration of naloxone prevented the appearance of these changes and also produced an increase (p < 0.01) of the organelles involved in the crinophagic phenomenon. These results suggest that the opioids play a modulating role, stimulating the synthesis and secretion of GH, which affects the ultrastructural features of the hypophyseal GH cells.

Partial coexistence of NADPH-diaphorase and somatostatin in the rat hypothalamic paraventricular nucleus

Coexistence of NADPH-diaphorase (ND) activity and somatostatin (SRIF) immunoreactivity was studied in the paraventricular nucleus (PVN) of the rat hypothalamus by successive incubations of the same sections. ND was found in all PVN subdivisions, mainly in the magnocellular ones. SRIF was practically restricted to the parvicellular periventricular subdivision. Contrary to other brain regions where a wide SRIF-ND coexistence has been observed, the periventricular parvicellular subdivision was the only place of the PVN where some neurons colocalize both markers. The combination of the immunocytochemical and the histochemical labelings allows a further permanent and easy-to-perform parcellation of periventricular PVN neurons.

Immunocytochemical evidence of hypothalamic regulation of adenohypophyseal VIP in the male rat

In order to check whether hypothalamic stimulatory or inhibitory factors exert any kind of modulation on the morphology of VIP-immunoreactive cells in the rat hypophysis, the transport of these towards the hypophyseal portal system was blocked by intraventricular administration of colchicine in adult male rats, thereafter performing a morphometric study after characterizing the VIP-immunoreactive adenohypophyseal cells by immunocytochemical techniques. Colchicine administration led to a significant increase (p < 0.01) in the number of reactive cells observed. These cells were characterized by a larger cellular area (p < 0.01), owing to increases in nuclear area (p < 0.05) and cytoplasmic area (p < 0.05). Their morphology became more regular, with a predominance of polygonal and oval cells. The results suggest that the VIP-reactive cells of the rat hypophysis are subject to a hypothalamic inhibitory influence and their activity increasing when the hypothalamic effect is interrupted by intraventricular administration of colchicine.