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Biomedical subjects

M Gil

Publications and source records attributed to M Gil.

At least 109 records · Page 6Linked to original sources
PubMed1992

Behavioral and neurochemical changes in response to acute stressors: influence of previous chronic exposure to immobilization.

The effect of daily (2 h) exposure to immobilization (IMO) for 15 days on the behavioral and neurochemical responses of adult male rats to acute stress caused by 2-h IMO or 2-h tail-shock was studied. The brain areas studied were frontal cortex, hippocampus, hypothalamus, midbrain, and pons plus medulla. Chronic exposure to IMO did not alter noradrenaline (NA), 3-methoxy,4-hydroxyphenyletileneglycol-SO4 (MHPG-SO4), serotonin, or 5-hydroxindoleacetic acid (5-HIAA) concentrations in any brain area as measured approximately 20 h after the last exposure to IMO. Exposure to behavioral tests did not modify neurochemical variables except NA levels in the hypothalamus of nonchronically stressed (control) rats. Both exposure to 2-h IMO or 2-h shock significantly decreased NA levels in hypothalamus and midbrain of nonchronically stressed rats. These decreases in response to the two acute stressors were not observed in chronically stressed rats. However, MHPG-SO4 levels increased to the same extent in control and chronically stressed rats after exposure to the acute stressors. Likewise, increased 5-HIAA concentrations observed in response to acute stressors were similar in control and chronically stressed rats. The inhibition of activity (areas crossed and rearing) in the holeboard caused by acute IMO was less marked in rats previously exposed to the same stressor than in control rats, but the response to shock was similar. In the forced swim test, acute IMO decreased struggling in control rats but tended to increase it in chronically stressed rats. The response to shock followed the same pattern as that to IMO, although it was slight.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Inhibition of catecholamine synthesis depresses behavior of rats in the holeboard and forced swim tests: influence of previous chronic stress.

Catecholaminergic pathways in the brain are activated during stress and are presumably involved in the control of physiological and behavioral changes triggered by stress. When repeatedly stressed, adaptive changes have been observed in catecholaminergic activity in the brain. In the present experiment, it was assessed whether or not chronic exposure to immobilization (IMO) altered the influence of catecholamines on behavior in the holeboard and forced swim test by administering alpha-methyl-p-tyrosine (an inhibitor of catecholamine synthesis). Adult Sprague-Dawley rats were used. Chronic stress amortiguated the inhibitory effect of acute IMO on some but not all behaviors in the two tests. Whereas previous chronic IMO exacerbated the effects of the drug on struggling and immobility in the forced swim test, no change in response to the drug as a consequence of chronic IMO was observed in the holeboard test. The present data suggest that chronic IMO-induced changes in the catecholaminergic control of some behaviors might be related to depression-like states in rats. The actual physiological meaning of these changes and the specific receptors involved remain to be elucidated.

Animals↗
PubMed1991

[A descriptive epidemiological study of ulcerative colitis in a community hospital (1985-1989)].

BACKGROUND: The incidence of ulcerative colitis (UC) shows a marked geographical variation. It is high in Anglo-Saxon and Scandinavian countries, while in Mediterranean countries the available data on its epidemiological features are few. Spain is not an exception. METHODS: The new cases of UC diagnosed during the period 1985-1989 in the Hospital de Sabadell (a reference center of an area with a markedly industrial population of 343924) were retrospectively evaluated. The definitive diagnosis of UC required a negative fecal microbiological study and findings in colonoscopy and biopsy consistent with UC. RESULTS: During the study period 68 new cases of UC were diagnosed, representing a mean yearly incidence of 3.95/10(5) population, and 5.26/10(5) considering only the adult population (age greater than 14 years). No significant differences were found (p greater than 0.05) in the sex and age distributions, although the male/female ratio was 1.06. In 84% of cases UC was limited to the rectum and/or distal colon, with a low frequency of pancolonic forms (5%). In 70% of patients UC was classified as a low severity disease. CONCLUSIONS: Although the estimation of incidence only from hospital cases underestimates the true incidence, and also considering the limitation of comparing results of studies from several time periods, the incidence of UC in our area is the highest one reported to the present time in Spain and Southern Europe. Nevertheless, it is lower than that in most Northern European countries.

Adolescent↗
PubMed1991

Influence of various acute stressors on the activity of adult male rats in a holeboard and in the forced swim test.

The effects of various acute stressors on the activity of adult male rats in a holeboard and in the forced swim test were studied. When tested immediately or 24 h after 1 h exposure to noise, restraint in tubes or tail shock, no changes in either defecation rate or activity in the holeboard were observed. In contrast, immediately after 1 h immobilization in wood-boards, a reduction of the number of areas crossed and the number of head-dips was found. The inhibitory effect of immobilization on head-dips persisted 24 h later. The behavior of the rats in the forced swim test was classified into three categories: struggling, mild swim and immobility. The changes in behavior were critically dependent on the type of stressor, and more specifically on its intensity, that was evaluated with three different physiological parameters (serum prolactin, corticosterone and glucose levels). Thus, if tested immediately after stress, noise did not alter the response of the rats, restraint in tubes and tail shock-reduced immobility, and the latter stressor increased mild swim. In the second experiment, immobilization in wood-boards reduced struggling. Twenty-four hours after stress, noise, restraint in tubes or tail shock were without effect, but immobilized rats showed increased immobility and reduced mild swim activity. The present data clearly indicate that behavior of rats in a holeboard and in a forced swim situation are not related, and that acute stress could have a differential effect on the various categories of behavior in a forced swim situation.

Animals↗
PubMed1990

The serum glucose response to acute stress is sensitive to the intensity of the stressor and to habituation.

The reliability of serum glucose concentrations as an index of habituation to chronic stress was evaluated in adult male rats. The glucose response to immobilization was attenuated by six days of previous chronic exposure to the same stressor, the degree of reduction being related to the duration (15 min, 1 hr or 4 hr) of the daily exposure to immobilization. In another experiment, three groups of rats were exposed to one of three stressors (handling plus change of room, restraint in tubes, or immobilization by wood boards), 1 hr daily for 27 days. On day 28, when faced with the same acute stressor to which they were chronically exposed, the rats showed a consistent reduction in glucose response, regardless of the type of stressor used. In addition, in stress-naive rats serum glucose levels were related to the intensity of the stressor as assessed by three independent measures (food intake, body weight changes, and adrenal weight after chronic exposure to the stressor). These data indicate that, under appropriate conditions, glucose levels can be a good index of both the intensity of acute stress experienced by the rats and their habituation to repeated stress.

Adrenal Glands↗
PubMed1989

[Role of intraoperative echo-Doppler color echocardiography in cardiac surgery. Preliminary study].

Intraoperative echocardiography with Doppler color flow imaging technique can provide the surgeon with an immediate and direct assessment of cardiac anatomy and function. To determine the utility of this recent technique, we have examined 15 patients pre, per, and postoperatively with Doppler color flow imaging. The intraoperative study was performed before and after cardiopulmonary bypass. A sterile transducer was placed directly on the epicardial surface of the heart, and multiple views were recorded. Intraoperative echocardiography with Doppler color flow imaging technique demonstrated excellent correlation with preoperative and postoperative findings, allowing an immediate evaluation of the surgical results. These preliminary results suggest that intraoperative Doppler color flow imaging technique is a valuable adjunct in heart surgery. It is particularly useful in valve repair, and in surgical repair of congenital heart disease.

Cardiac Surgical Procedures↗
PubMed1988

Simultaneous purification and characterization of aspartate aminotransferase isoenzymes from chicken liver.

Cytosolic and mitochondrial isoenzymes of aspartate aminotransferase (EC 2.6.1.1) were purified to homogeneity from chicken liver, without previous fractionation of the subcellular components. The procedure includes initial heat treatment and ammonium sulfate fractionation. The two isoenzymes can then be separated by a DEAE-Sepharose chromatography using a linear gradient of L-aspartate (reaction substrate). The separated fractions can be further purified by a parallel step with HA-Ultrogel prior to octyl-Sepharose (c-AAT) and CM-Sepharose (m-AAT) chromatographies. Michaelis constants, pI values, inhibition by adipate and subforms generation with time were studied for both isoenzymes.

Animals↗
PubMed1987

Intramitochondrial location and some characteristics of chicken liver aspartate aminotransferase.

Chicken liver mitochondrial aspartate aminotransferase was found to be located in the intermembrane space and bound to the inner mitochondrial membrane. Purification of two mitochondrial fractions containing aspartate aminotransferase activity was performed. Both fractions showed similar chromatographic behaviour and identical isoelectric point and molecular weight values. There were no significant differences in the general kinetic mechanism, Km values, substrates inhibition and effect of various anions on the activity of mitochondrial aspartate aminotransferase purified from both fractions.

Animals↗
PubMed1987

A kinetic method for quantification of aspartate aminotransferase isoenzymes.

A spectrophotometric assay is proposed to determine the levels of aspartate aminotransferase (AAT) isoenzymes from chicken liver by a steady-state kinetic method which depends on the differential inhibition of these isoenzyme forms by high concentrations of substrate 2-oxoglutarate at pH 6.2. The use of a standard curve permits the determination of the percentage of chicken liver c-AAT and m-AAT isoenzymes. This method yields results in good correlation with those achieved by different extent adipate inhibition and by differential centrifugation.

Animals↗
PubMed1985

The transition stages between the main aphasic syndromes.

One of the basic features of most aphasic patients is their clinical dynamics, i.e. the continuous change in language function. The functional Dynamic Approach on which our rehabilitation program is based, can be expressed as a model of dynamic movement in which a patient's progress from one syndrome to another can be documented quantitatively. In this study we have concentrated on the initial emergence of patients out of the major syndrome categories. Our language test "I.L.A.T." provides for the evaluation of changes in the four language functions. Relative changes are charted by establishing a theoretical maximum performance to be expected in an aphasic population and noting improvements from the initial condition towards that point. Quantification of the proposed transitional stages are currently being developed to document our clinical insights.

Anomia↗