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Biomedical subjects

C González

Publications and source records attributed to C González.

At least 19 recordsLinked to original sources
PubMed1992

Downregulation of hepatic albumin mRNA in response to induced hypercholesterolemia in rabbits.

Albumin gene expression was studied in rabbits fed on a cholesterol-rich diet for up to 16 weeks. Livers from experimental animals showed extensive lipid deposition. Hepatic albumin mRNA abundance decreased along the treatment to very low levels after 16 weeks. An 8-fold decrease in the rate of transcription of this gene was also detected. This downregulation of albumin gene expression cannot be attributed to a general impairment of RNA synthesis, as expression of other liver-specific and housekeeping genes did not vary significantly. There was a decrease in ascitic fluid albumin levels after 10 weeks, although serum albumin levels remained unchanged throughout the treatment. Our results are discussed in view of the relationship of albumin levels with hypercholesterolemia.

Animals↗
PubMed1992

[Mental disorders and the utilization of the general medicine consultation].

OBJECTIVE: To study the quantitative relationship that exists between mental problems and use of the general medical practitioner, and the association between such problems, increased use of the medical services, and morbidity and socio-demographic variables. DESIGN: Observational cross-section study. SITE. A primary care team's general medical consultations. PATIENTS: Patients aged over 15, attending the consultations. A sample of 310 patients was selected using systematic sampling. INTERVENTIONS: The Mental Health GHQ, 28 items questionnaire was administered to the patients, to detect the existence of significant mental health disorders. MEASUREMENT AND MAIN RESULTS: Amongst older patients there is a greater incidence of mental illness, statistically significant at p less than 0.01. Also significant at p < 0.01 were the greater number of visits to the doctor amongst patients previously diagnosed as having mental disorders, amongst the elderly, those patients included in health programmes and those who showed greater take-up of supplementary explorations and interim consultations. CONCLUSIONS: The results demonstrate an association between mental illness and greater number of visits to the general practitioner, leading to the hypothesis that a considerable number of such visits could be attributed to mental illness. There is no doubt that it is important to integrate the mental health services into primary care practice.

Age Factors↗
PubMed1992

Nitric oxide mediates tumor necrosis factor-alpha cytotoxicity in endothelial cells.

Tumor necrosis factor alpha (TNF-alpha) exerts multiple actions on endothelial cells including among others the expression of pro-coagulant activity and adhesion molecules, and secretion of cytokines. We now show that TNF-alpha induces a time- and dose-dependent cytotoxic effect on cultured bovine aortic endothelial cells. This TNF-induced cytotoxicity, which is preceded by increased production of nitric oxide (NO), is significantly decreased by the NO synthase inhibitor N-iminoethyl-L-ornithine (L-NIO). Dexamethasone, which prevents the expression of cytokine-induced NO synthase in endothelial cells, also inhibits TNF-alpha-dependent cytotoxicity. The results indicate that NO is involved in the cytotoxic effect of TNF-alpha on endothelial cells.

Amino Acid Oxidoreductases↗
PubMed1992

Potentiation by cyclooxygenase inhibitors of the release of catecholamines from the rabbit carotid body and its reversal by prostaglandin E2.

Salicylates, at the high therapeutic doses used in the treatment of rheumatoid arthritis, produce an increase in ventilation and augment the carotid body reactivity to hypoxic stimulus, leading to an exaggerated hyperventilation during hypoxia. These effects had been related to the action of salicylates as uncouplers of oxidative phosphorylation. In the present study, carried out in an in vitro preparation of the rabbit carotid body, we show that acetylsalicylic acid and indomethacin, two anti-inflammatory drugs that are also powerful inhibitors of cyclooxygenase, the prostaglandin-synthetizing enzyme, produce an increase in the [3H]catecholamine release evoked by low oxygen stimulation. The drugs did not affect basal normoxic release, a finding that suggests that at the concentration used these anti-inflammatory agents do not have uncoupling actions, and that their effects on hypoxic-induced release of [3H]catecholamines is mediated by their specific action as cyclooxygenase inhibitors. In agreement with this suggestion we found that prostaglandin E2 completely prevented the effects of both anti-inflammatory agents. In addition, our data indicate that endogenously synthetized prostaglandins are powerful modulators of chemoreceptor cell function.

Animals↗
PubMed1992

Time course of K+ current inhibition by low oxygen in chemoreceptor cells of adult rabbit carotid body. Effects of carbon monoxide.

K+ currents recorded from adult rabbit chemoreceptor cells are reversibly inhibited on lowering the pO2 in the bathing solution. Bath application of a hypoxic TTX-containing solution revealed that inhibition of K+ current by low pO2 proceeds faster than TTX inhibition of Na+ currents, the apparent t1/2 being 3.68 and 7.14 s, respectively. Addition of carbon monoxide to the hypoxic gas mixture used to equilibrate the bathing solution reversed the inhibition of K+ currents by approx. 70%.

Animals↗
PubMed1992

Proliferation index in bone marrow cells from severely malnourished rats during lactation.

The aim of this study was to determine if severe malnutrition affects the proportion of proliferating bone marrow cells in malnourished rats during lactation. Sister chromatid staining of metaphases was used as a parameter, as well as the morphology, size and color of bromodeoxyuridine labeled interphase nuclei. The BrdU proliferation labeling index was statistically lower in malnourished rats (20.4%), than in well-nourished controls (35.1%). A difference was also found between the two groups in the proportion of metaphases in first, second and third or successive cell cycle. The average generation time was longer in the malnourished group: 15.3 h, against 11.8 h for the controls. These results indicate that severe malnutrition affects both the proportion of bone marrow proliferating cells and their cell kinetics.

Animals↗
PubMed1992

Oxygen and acid chemoreception in the carotid body chemoreceptors.

The carotid bodies are arterial chemoreceptors that are sensitive to blood PO2, PCO2 and pH. They are the origin of reflexes that are crucial for maintaining PCO2 and pH in the internal milieu and for adjusting the O2 supply according to the metabolic needs of the organism in situations of increased demand, such as exercise and while breathing at decreased O2 partial pressures during ascent or when living at high altitude. Chemoreceptor cells of the carotid body transduce the blood-borne stimuli into a neurosecretory response that is dependent on external Ca2+. These cells have an O2-sensitive K+ current that is reversibly inhibited by low PO2. It is proposed that the depolarization produced by inhibition of this K+ current activates Ca2+ channels; Ca2+ influx and neurosecretion follow. The cells have also a potent Na(+)-Ca2+ antiporter that could be responsible for the intracellular Ca2+ rise required to trigger the release of neurotransmitters during high PCO2 or low pH stimulation.

Acids↗
PubMed1992

Effect of nitrogen source on the levels of nitrate reductase in the yeast Hansenula anomala.

Levels of nitrate reductase (NR) protein in Hansenula anomala and Hansenula wingei were determined using specific antiserum raised against the enzyme from H. anomala. Extracts from nitrate-grown cells contained NR protein, while in those from cells grown on ammonium, glutamine or peptone, no cross-reacting material could be observed. Enzyme activity correlated with the levels of cross-reacting material. When nitrate was used as nitrogen source, NR was always present, even in cultures with ammonium, glutamine or peptone, although in these cases both the levels of activity and protein were lower. NR activity was consistently two to four times higher in cells grown in glucose than in cells grown in ethanol. Nitrate was required for NR induction, and deprivation of nitrate from nitrate-grown cells resulted in a rapid loss of NR activity.

Cycloheximide↗
PubMed1992

Characterization of cultured chemoreceptor cells dissociated from adult rabbit carotid body.

Short-term cell cultures were obtained from enzymatically dissociated carotid bodies from adult rabbits, and morphological and functional characterization of the cultured chemoreceptor cells were carried out. Under phase contrast, freshly isolated type I cells are round, bright, and 10-14 microns in diameter and exhibit strong fluorescence when stained with the glyoxylic acid technique. The content of endogenous dopamine in the cultures increased from 80 pmol/10(5) cells 2 h after plating the cells to 200 pmol/10(5) cells on the 3rd day, and the rate of synthesis and storage of [3H]dopamine from the precursor [3H]tyrosine increased from 1.7 pmol.10(5) cells-1.h-1 in 1-day cultures to 4 pmol.10(5) cells-1.h-1 on the 3rd day; the later values represent 80-85% of the expected values for the intact carotid body. After labeling with [3H]tyrosine, cultured chemoreceptor cells release [3H]dopamine when challenged by hypoxia, high external K+, or the protonophore dinitrophenol, the pattern of response being similar to that of the intact carotid body. When studied by whole cell clamp recording, individual chemoreceptor cells exhibit a marked variability in the properties of some ionic currents; the data, however, do not support the existence of distinct subpopulations of type I cells.

Animals↗
PubMed1992

[A kinetic model for heparin dosing in patients on chronic hemodialysis].

The quality of anticoagulation was evaluated in 5 patients receiving heparin during chronic hemodialysis. 50 kinetic studies were performed using 2 monitoring tests, TTPK and TCK. Basal and intradialysis measurements were used to estimate sensitivity and the elimination constant according to formulae described by Milthorpe. Mean basal TTPK time was 27.3 sec and TCK time was 211 sec. Mean initial intradialysis TTPK time was 107.5 sec and after correction applying the kinetic model it was 62 sec. Intradialysis TCK time varied from 806 to 683 sec after correction. At the end of the study, mean intradialysis TTPK time was 61 sec not significantly different from the target time of 55 sec. TCK time, however, was significantly greater than target (684 vs 434 sec).

Adult↗
PubMed1992

[The fall of the Jericho walls].

Archeologic and medical evidence and biblical texts were analyzed in search of support for the hypothesis that the fall of Jerico walls might have been related to an epidemic caused by Schistozoma hematobium. There is evidence of the presence of Balinus trunctus, a snail acting as an intermediary host, but not of the disease itself. However, the hypothesis could still be tenable if all inhabitants left the city, which is suggested by all available evidence. The text in Re 2: 19-22 may not be taken as literary evidence of infection by the agent under discussion.

Bible↗
PubMed1992

[Treatment with ubiquinone in Kearns-Sayre syndrome. Improvement in ocular motility and visual evoked potentials].

In 1985 Ogasahara observed that treatment with ubiquinone produced improvement in the cardiac conduction and the metabolism of the lactic and pyruvic acids in the Kearns-Sayre syndrome. The results of the administration of 150 mg/day of ubiquinone for 3 years in a patient diagnosed with the Kearns-Sayre syndrome is described. The patient improved notably in strength, ocular movement, visual evoked potentials and in the metabolism of lactic and pyruvic acids. Other beneficial effects reported in the literature have been improvement of ataxia and the somato-sensitive evoked potentials. No side effects have been described.

Adolescent↗
PubMed1992

Hepatic actinomycosis presenting as liver mass: case report and review of the literature.

Primary hepatic actinomycosis is an uncommon entity. We report the case of a young man with past history of an appendectomy who presented with fever, weight loss and a liver mass that was initially suspected to be neoplastic. Percutaneous liver biopsy revealed actinomyces-like organisms. The patient was treated with intravenous and oral penicillin with good therapeutic response. Review of the literature and correlation between hepatic actinomycosis and previous appendectomy are considered.

Actinomyces↗