Search PubMed⌕ Search

Biomedical subjects

B Fernandez

Publications and source records attributed to B Fernandez.

At least 55 records · Page 3Linked to original sources
PubMed1993

Phosphatidylcholine hydrolysis activates NF-kappa B and increases human immunodeficiency virus replication in human monocytes and T lymphocytes.

We have tested whether breakdown of phosphatidylcholine (PC) initiated by exogenous addition of a PC-specific phospholipase C (PC-PLC) from Bacillus cereus or by endogenous overexpression of PC-PLC induces functional activation of NF-kappa B and increases human immunodeficiency virus (HIV) enhancer activity. PC-PLC-activated hydrolysis of PC was found to induce bona fide p50/p65 NF-kappa B binding activity in three different cell lines of human or murine origin. No significant changes in the turnover of other cellular phospholipids were detected in PC-PLC-treated cells. Induction of NF-kappa B by PC-PLC did not depend on de novo synthesis of proteins or autocrine secretion of either tumor necrosis factor or interleukin 1. In human monocytic and lymphoblastoid T-cell lines, induction of NF-kappa B by PC-PLC resulted in clear induction of luciferase expression vectors placed under the control of synthetic kappa B enhancers or wild type, but not kappa B-mutated, HIV long terminal repeat constructs. HIV replication was increased by PC-PLC in chronically infected monocytes and T lymphocytes. NF-kappa B activation promoted by addition of exogenous PC-PLC correlated with an intense production of diacylglycerol. However, addition of a phosphatidylinositol-specific PLC from B. cereus also induced diacylglycerol but did not activate kappa B enhancer-directed vectors. PC-PLC-induced NF-kappa B activation could not be blocked by a specific inhibitor of phorbol ester-inducible protein kinases C. These results indicate that a cellular transduction pathway, dependent on specific PC breakdown, is functional in T lymphocytes and monocytes and may be used by various transmembrane receptors to activate HIV transcription through NF-kappa B-dependent induction of the HIV enhancer.

Cell Line↗
PubMed1993

[Comparative study of the diaphyseal osseous growth of the tibia between 3 and 12 weeks in 2 strains of turkey: histological and histomorphometric aspects].

The comparative cortical growth of the tibiotarsus was studied in 2 turkey strains, one light, one heavy, between 3 and 12 weeks of age, using histological and histomorphometrical methods. The growth in thickness started earlier and was much faster and larger in the heavier turkey strain. The early ovoid shape of the cortex of the heavier strain and the difference between the thickness of the narrow and the thick cortical faces seemed to be related to the action of strong mechanical strains. Nevertheless the diaphyseal cortical ratio remained not significantly different in the 2 strains from the age of 3 weeks. The light strain exhibited during all the studied periods indicated a more variable mineral apposition rate and earlier and more extensive bone remodelling phenomena. Most of the growth in thickness parameters were significantly higher in the heavier strain when turkeys of the 2 strains were compared at an equivalent weight.

Age Factors↗
PubMed1992

Glial fibrillary acidic protein and vimentin immunohistochemistry in the posterior rhombencephalon of the Iberian barb (Barbus comiza).

The gustatory centers (vagal lobes and facial lobe) and the tegment of the posterior rhombencephalon of the Iberian barb (Barbus comiza) have been studied using anti-glial fibrillary acidic protein (anti-GFAP) and anti-vimentin immunohistochemical techniques. GFAP immunoreactivity was found in the tegment and in a part of the vagal lobes while vimentin immunoreactivity was located in the tegment. Two immunopositive cell types were found: ependymocytes and radial astrocytes. Since the distribution of GFAP in the barb rhombencephalon corresponds with zones previously described as cholinergic, the GFAP-immunopositive radial astrocytes might be involved in acetylcholine metabolism.

Animals↗
PubMed1992

The pretectal complex of the rabbit: distribution of acetylcholinesterase and reduced nicotinamide adenine dinucleotide diaphorase activities.

The chemoarchitecture of the pretectal complex of the rabbit was examined in sections stained by acetylcholinesterase (AChE) and reduced nicotinamide adenine dinucleotide (NADH) diaphorase in the coronal, horizontal and sagittal plane. Twelve different subdivisions can be identified in the rabbit pretectum on the basis of the distribution of both histochemical markers. According to the standard terminology, the pretectal complex of the rabbit consists of: the nucleus of the optic tract; the anterior, posterior, olivary and medial pretectal nuclei; the nucleus of the posterior commissure; the periventricular subcommissural gray; the suprageniculate and internal suprageniculate nuclei, and the dorsal, lateral and medial terminal nuclei of the accessory optic system. The combined use of several sectioning planes and the histochemical mapping of AChE and NADH diaphorase have been of value in resolving the structural limits within transitional regions of the pretectum.

Acetylcholinesterase↗
PubMed1992

Unusual glial cells in sensory ganglia.

Unusual glial cells not related with perikarya or fibres were observed with the electron microscope in dorsal root spinal ganglia. These interstitial cells were very electron dense, with big and irregularly shaped nucleus and scanty organelles. They occurred immersed in the endoneurial space tissue, with no basal lamina and presented no contacts with other cells. In addition to these interstitial cells present both in kittens and adult cats, younger kitten sensory ganglia contained refringent glial cells.

Aging↗
PubMed1991

Comparative mapping of acetylcholinesterase and reduced nicotinamide adenine dinucleotide diaphorase in the rabbit dorsal thalamus.

The distribution of acetylcholinesterase and reduced nicotinamide adenine dinucleotide (NADH) diaphorase enzymatic activities was mapped histochemically in the dorsal thalamus of the rabbit. A comparison of the resulting patterns helped in the histochemical delimitation of a number of nuclei, as well as in the detection of some subdivisions, that showed differential expression of these enzymes. It was observed that AChE and NADH diaphorase tend to appear in a complementary fashion in many dorsal thalamic neuropiles, so that intense activity of the one was accompanied by low activity of the other. However, coincident expression of both enzymes was also obtained in a small number of areas. The correlation of these patterns with other chemo-architectonic and hodologic data does not yet disclose an explanation of these regularities, which however suggest some functional significance.

Acetylcholinesterase↗
PubMed1991

Cellular immunity in current active pulmonary tuberculosis.

A group of 10 patients with recently diagnosed pulmonary TB were studied and compared to 10 bacillus Calmette-Guérin (BCG) immunized healthy individuals. Cellular immune mechanisms were explored in vitro utilizing fresh and precultured peripheral blood mononuclear cells exposed to PHA, PPD, and recall antigens (SK/SD and CA). Proliferative assays were also carried out in the presence of either each patient's serum (autologous serum) or cocultured with CD3(+)-depleted adherent cells. Serum measurements of soluble interleukin-2 (IL-2) receptor and synthesis of IL-2 generated by mononuclear cells stimulated with PPD and SK/SD were also performed. Patient sera were able to inhibit autologous as well as allogeneic cell responses, and a significant adherent cell suppressive effect was observed. As a whole the group of patients showed decreased blast transformation to PPD, preserved proliferative responses to other recall antigens, and a low PPD-induced generation of IL-2. Furthermore, as possible evidence of preactivated T cells, these patients demonstrated high soluble IL-2 receptor serum levels. Early compromise of specific cell-mediated immunity, including IL-2 abnormalities, may be of significance in newly diagnosed pulmonary TB.

Adult↗
PubMed1991

Comparative study of the glial fibrillary acidic protein (GFAP) in toad, kitten and cat sensory ganglia.

The peroxidase-antiperoxidase (PAP) method was used on paraffin embedded tissue to demonstrate the presence of the glial fibrillary acidic protein (GFAP) in sensory ganglia of kittens, cats and toads. Special attention was paid to the influence of fixation. It appeared that the final immunostaining of GFAP depends on the fixative and on the species used. GFAP was found in cat sensory ganglia at birth and at all subsequent stages studied. The satellite cells from toad sensory ganglia were also positive, although they displayed a weaker immunoreactivity. The amphibian material showed a clear sensitivity to the fixative used.

Aging↗
PubMed1991

Sexual dimorphism in the distribution of glial fibrillary acidic protein in the supraoptic nucleus of the hamster.

The supraoptic nuclei (SON) of the hypothalamus of male and female hamsters were examined immunohistochemically at 1 month of age for possible sex differences in astroglial organisation. The morphometric analysis revealed the presence of more glial fibrillary acidic protein (GFAP) immunostaining in the SON of males as compared with females. GFAP-positive processes were located among the neurosecretory neurons in the males, but were quite scarce among these neurons in the female SON. These results indicate the existence of sexual dimorphism in the SON which could be mediated by sex steroids.

Animals↗
PubMed1990

Praziquantel treatment of porcine brain and muscle Taenia solium cysticercosis. 1. Radiological, physiological and histopathological studies.

Porcine Taenia solium cysticercosis, recognized as a model of the human disease, was used to analyze the effect of the anthelminthic drug praziquantel on hosts and parasites. The drug (50 mg/kg daily) was given over 15 days in the feed of 13 cysticercotic and 9 control pigs. Changes in the number, size and appearance of brain parasites were seen by computerized tomography immediately after the last dose of praziquantel, although not all cysticerci had disappeared by day 47 following the end of the treatment. Muscle parasites became small and hyperdense shortly after treatment and disappeared from tomographic images afterwards. No alterations were found in EEGs or in brain-stem auditory and somatosensory evoked potentials. Muscle cysticerci showed increasing degrees of degeneration with time after treatment, and an augmented inflammatory reaction was concomitantly observed. In contrast, more heterogeneous results were obtained in parasites lodged in the brain, since viable cysts and less intense inflammatory reactions were found in the brain at different times after treatment. Physiological evaluation of the parasites showed that evagination was inhibited immediately after treatment and that oxygen consumption decreased with time. The results of this investigation suggest that praziquantel damages cysticerci and that the inflammatory reaction destroys and eliminates them.

Animals↗
PubMed1990

Relationship between adenohypophyseal and steroid hormones and variations in serum and urinary melatonin levels during the ovarian cycle, perimenopause and menopause in healthy women.

Morning levels of serum melatonin, FSH, LH, prolactin (PRL), progesterone and estradiol were studied by RIA during the ovarian cycle, perimenopause and menopause in 79 healthy women. FSH and LH levels showed a slight nonsignificant increase from the fertile period to perimenopause, exhibiting a significantly greater increase during menopause. PRL, progesterone and estradiol showed parallel changes, reaching lower levels during menopause. Serum melatonin levels decreased with age, attaining minimum levels in menopause. FSH and estradiol were significantly correlated with melatonin in the follicular phase, while in the luteal phase a negative correlation was found between melatonin, progesterone and estradiol. No significant correlations were noted between serum hormone levels during the perimenopausal period. In menopause, as during the follicular phase, melatonin and FSH were negatively correlated. As expected, a significant positive correlation was found between morning serum levels of melatonin and nocturnal urinary excretion of this indoleamine in all groups studied.

Adult↗
PubMed1990

Case report and review of resolved fusariosis.

Erythematous macules, nonpalpable and palpable purpura, and flaccid pustules developed in a 59-year-old man with acute lymphocytic leukemia 8 days after reinduction chemotherapy with cytosine arabinoside and daunorubicin. Tissue and blood cultures grew Fusarium proliferatum, and a skin biopsy specimen revealed fungal vasculitis. Anemia and muscle weakness accompanied the disseminated infection, for which the patient received granulocyte transfusions and amphotericin B, ketoconazole, rifampin, and griseofulvin. Skin lesions and fungemia resolved with recovery of the bone marrow, and 51 days after the completion of his chemotherapy he returned home. If promptly recognized and aggressively treated, disseminated fusariosis is responsive to therapy. Infection with Fusarium species should be suspected in profoundly neutropenic patients in whom disseminated palpable purpura and myositis develop concomitantly.

Amphotericin B↗
PubMed1990

Ultrastructure of the subpial glial limitans in the cerebellum of the lizard (Lacerta lepida).

The subpial glial limitans in the cerebellum of the lizard (Lacerta lepida) is a single layer formed by the extensions of the fibers of Bergmann's glia. These subpial extensions present a prismatic aspect, few organelles and abundant whorls of smooth endoplasmic reticulum. These whorls of endoplasmic reticulum appear as concentric and tubular membranous formations. The glial limitans is not continuous at times.

Animals↗
PubMed1989

Biochemical characterization of phospholipase D activity from human neutrophils.

We have found a phospholipase D activity in the postnuclear fraction of human neutrophils, employing phosphatidylinositol as exogenous substrate. This phospholipase D activity was assessed by both phosphatidate formation and by free inositol release in the presence of 15 mM LiCl in the reaction mixture and in the absence of Mg2+ ions to prevent inositol-1-phosphate phosphatase activity. To assess further the phospholipase D activity, we studied its capacity to catalyze a transphosphatidylation reaction, as a unique feature of the enzyme. It was detected as [14C]phosphatidylethanol formation when the postnuclear fraction was incubated with [14C]phosphatidylinositol in the presence of ethanol. The phospholipase D showed a major optimum pH at 7.5 and a minor one at pH 5.0. Neutral and acid phospholipase D activities were differentially located in subcellular fractionation studies of resting neutrophils, namely in the cytosol and in the azurophilic granules, respectively. Neutral phospholipase D required Ca2+ ions to the active, whereas the acid enzyme activity was Ca2(+)-independent. The neutral phospholipase D activity showed a certain specificity for phosphatidylinositol, as it was able to hydrolyze phosphatidylinositol at a much higher rate than phosphatidylcholine, in the absence and in the presence of different detergents. This neutral phospholipase D activity behaved as a protein of high molecular mass (350-400 kDa) by gel filtration chromatography. Moreover, neutral phospholipase D activity was detected in the postnuclear fraction of human monocytes, by measuring free inositol release from phosphatidylinositol as exogenous substrate, under the same experimental conditions as those used with neutrophils. The enzyme displayed similar specific activities in both cell types as well as the same degree of activation after cell stimulation with the calcium ionophore A23187. These results demonstrate the existence of two phospholipase D activities with different pH optima and intracellular location in human neutrophils. Furthermore, these results suggest that this phospholipase D can play a role in signal-transducing processes during cell stimulation in human phagocytes.

Cell Fractionation↗