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Biomedical subjects

M Gomez

Publications and source records attributed to M Gomez.

At least 91 records · Page 5Linked to original sources
PubMed1995

Evaluation of predictive ability of APACHE II system and hospital outcome in Canadian intensive care unit patients.

OBJECTIVES: To evaluate the ability of the acute Physiology and Chronic Health Evaluation II (APACHE II) scoring system to predict patient outcome in two Canadian intensive care units (ICUs). To compare the severity of illness and outcome of Canadian ICU patients with existing United States data. DESIGN: Prospective data collection on 1,724 Canadian ICU patients for validation of the APACHE II system. Comparison of the outcome of Canadian ICU patients to retrospective United States data on 4,087 patients from the 1985 APACHE II multicenter study. SETTING: Canadian data from two university teaching hospital ICUs. United States data from 13 ICUs, ten of which were in university teaching hospitals. PATIENTS: Consecutive patients admitted to adult medical/surgical ICUs. Coronary care unit, neurosurgical and cardiac surgery patients were excluded. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: For each patient, demographic data, diagnosis, APACHE II score and hospital survival data were collected. The predicted risk of death was calculated for each patient using the APACHE II risk of death equation. The accuracy in outcome prediction of the APACHE II system was assessed by means of the receiver operating characteristic curve, 2 x 2 decision matrices and linear regression analysis. The severity of illness and hospital mortality for the Canadian patients was compared with that of United States patients from the 1985 APACHE II multicenter study. In 1,724 Canadian ICU patients, the mean +/- SEM APACHE II score was 16.5 +/- 0.2. The predicted death rate was 24.7% and the observed death rate was 24.8%. Using receiver operating curve analysis, good correlation was found between predicted outcome and observed outcome. The area under the curve was 0.86. From the 2 x 2 decision matrix constructed for a predicted risk of death of 0.5, 83% of patients were correctly classified. The sensitivity was 50.9% and the specificity was 93.6%. When observed death rate was plotted against predicted death rate, linear regression analysis gave an r2 of .99. Canadian patients had a higher death rate and APACHE II score than the United States patients. After controlling for severity of illness using the APACHE II score, the Canadian and United States death rates were similar. CONCLUSIONS: The ability of the APACHE II system in predicting group outcome is validated in this Canadian ICU population by receiver operating characteristic curve, 2 x 2 decision matrices and linear regression analysis. The Canadian patients had a higher overall hospital death rate than the United States patients. After controlling for severity of illness using APACHE II scores, the hospital death rate was comparable between the Canadian and United States patients.

APACHE↗
PubMed1995

Differential actions of exogenous and intracellular spermine on contractile activity in smooth muscle of rat portal vein.

Effects of the naturally occurring polyamine spermine on electrical and contractile properties of the rat portal vein were studied. 1 mM spermine nearly abolished spike activity and spontaneous contractions and decreased the intracellular Ca2+ concentration ([Ca2+]i). The phasic force responses to 0.1 and 1 microM phenylephrine were partially inhibited, but not the sustain plateau contraction caused by 5 microM phenylephrine. The Ca(2+)-force relation in high-K+ (128 mM)-depolarized veins was shifted to the right, EC50 for Ca2+ increasing from 0.50 +/- 0.03 mM (control, n = 8) to 0.65 +/- 0.06 and to 0.94 +/- 0.03 at 1 (n = 4) and 10 (n = 3) mM spermine, respectively. However, at a Ca2+ concentration of 2.5 mM, giving maximal force, there was no effect of spermine (1 mM) on either force or [Ca2+]i. Whereas extracellular spermine thus reduced contractile activity at moderate levels of stimulation, increased intracellular concentration of spermine potentiated the force response to Ca2+. Intracellular loading of spermine by reversible permeabilization increased its concentration by 2-3 times. The spontaneous activity and response to phenylephrine were unchanged. However, the Ca(2+)-force relation of depolarized veins was shifted to the left, EC50 decreasing from 0.51 +/- 0.04 mM in controls (n = 7) to 0.36 +/- 0.02 mM in the loaded veins (n = 9). Spermine increased Ca(2+)-activated force in portal veins permeabilized with beta-escin. The degree of potentiation was consistent with observed effects in spermine-loaded intact veins. The results suggest that spermine at physiological intracellular concentration may contribute to the determination of Ca2+ sensitivity in vascular smooth muscle cells.

Animals↗
PubMed1995

Effects of arbuscular-mycorrhizal glomus species on drought tolerance: physiological and nutritional plant responses.

The tolerance of lettuce plants (Lactuca sativa L. cv. Romana) to drought stress differed with the arbuscular-mycorrhizal fungal isolate with which the plants were associated. Seven fungal species belonging to the genus Glomus were studied for their ability to enhance the drought tolerance of lettuce plants. These fungi had different traits that affected the drought resistance of host plants. The ranking of arbuscular-mycorrhizal fungal effects on drought tolerance, based on the relative decreases in shoot dry weight, was as follows: Glomus deserticola > Glomus fasciculatum > Glomus mosseae > Glomus etunicatum > Glomus intraradices > Glomus caledonium > Glomus occultum. In this comparative study specific mycorrhizal fungi had consistent effects on plant growth, mineral uptake, the CO(inf2) exchange rate, water use efficiency, transpiration, stomatal conductance, photosynthetic phosphorus use efficiency, and proline accumulation under either well-watered or drought-stressed conditions. The ability of the isolates to maintain plant growth effectively under water stress conditions was related to higher transpiration rates, levels of leaf conductance, and proline, N, and P contents. Differences in proline accumulation in leaves among the fungal symbioses suggested that the fungi were able to induce different degrees of osmotic adjustment. The detrimental effects of drought were not related to decreases in photosynthesis or water use efficiency. Neither of these parameters was related to P nutrition. The differences in P and K acquisition, transpiration, and stomatal conductance were related to the mycorrhizal efficiencies of the different fungi. Our observations revealed the propensities of different Glomus species to assert their protective effects during plant water stress. The greater effectiveness of G. deserticola in improving water deficit tolerance was associated with the lowest level of growth reduction (9%) under stress conditions. The growth of plants colonized by G. occultum was reduced by 70% after a progressive drought stress period. In general, the different protective effects of the mycorrhizal isolates were not associated with colonizing ability. Nevertheless, G. deserticola was the most efficient fungus and exhibited the highest levels of mycorrhizal colonization, as well as the greatest stimulation of physiological parameters.

Journal Article↗
PubMed1995

Transcription of spoIVB is the only role of sigma G that is essential for pro-sigma K processing during spore formation in Bacillus subtilis.

Activation of pro-sigma K processing in the mother cell at late stages of sporulation in Bacillus subtilis requires the presence of active sigma G in the forespore. Placing the spoIVB gene under the control of sigma F, the early forespore transcription factor, allows sigma K to become active in the absence of sigma G. Therefore, transcription of spoIVB is the only role of sigma G that is essential for the signaling pathway between sigma G and sigma K.

Bacillus subtilis↗
PubMed1995

Treatment of recurrent and resistant CAPD peritonitis by temporary withdrawal of peritoneal dialysis without removal of the catheter.

Recurrent and resistant continuous ambulatory peritoneal dialysis (CAPD) peritonitis is usually treated by removal of the catheter and temporary hemodialysis. We treated 3 patients: 1 with resistant Klebsiella peritonitis and 2 with recurrent peritonitis (one due to Staphylococcus and the other to Enterococcus), by stopping CAPD for a 2-4 week period, leaving the catheter in situ and continuing antibiotic therapy. All 3 patients had resolution of their infections and restarted CAPD. This therapeutic modality reduced catheter replacements, limited admissions to the hospital, reduced psychological impact, and diminished risks and costs of CAPD.

Adult↗
PubMed1995

Four-week oral toxicity study of 1,2-dimethyl-3-hydroxypyrid-4-one (L1) in uremic rats.

A short-term oral toxicity study of 1,2-dimethyl-3-hydroxypyrid-4-one (L1), a promising oral chelating agent for the treatment of iron and aluminum overload, was carried out in uremic rats. L1 was administered to male uremic rats by gastric intubation at 0, 20, 40, 80 or 160 mg/kg/d for 4 w. Body weight and food and fluid intake were monitored daily. Complete hematologic examinations, serum biochemical parameter determinations and histological examinations were carried out. Although body weight gain was significantly reduced at 80 and 160 mg/kg/d, there were no effects of L1 on food and fluid consumption. There were no significant differences between controls and L1-treated groups in most of the hematological and biochemical parameters analyzed. No significant dose-dependent changes in relative organ weights were noted. The non-observed-adverse-effect level (NOAEL) for L1 in uremic rats was 40 mg/kg/d. According to the results of this study, uremia did not increase the toxic effects of L1.

Administration, Oral↗
PubMed1994

Physiological properties of neuronal nicotinic receptors reconstituted from the vertebrate beta 2 subunit and Drosophila alpha subunits.

Three cDNAs (ALS, D alpha 2 and ARD) isolated from the nervous system of Drosophila and encoding putative nicotinic acetylcholine receptor subunits were expressed in Xenopus oocytes in order to study their functional properties. Functional receptors could not be reconstituted from any of these subunits taken singly or in twos and threes. In contrast, large evoked currents (in the microA range) were consistently observed upon agonist application on oocytes co-injected with ALS or D alpha 2 in combination with the chick beta 2 structural subunit. The ALS/beta 2 and D alpha 2/beta 2 receptors are highly sensitive to acetylcholine and nicotine, and their physiological properties resemble those of native or reconstituted receptors from vertebrates. Although the physiological properties of ALS/beta 2 and D alpha 2/beta 2 receptors are quite similar, clear differences appear in their pharmacological profiles. The ALS/beta 2 receptor is highly sensitive to alpha-bungarotoxin while the D alpha 2/beta 2 receptor is totally insensitive to this agent. These results demonstrate that the Drosophila ALS and D alpha 2 cDNAs encode neuronal nicotinic subunits responding to physiological concentrations of the agonists acetylcholine and nicotine.

Animals↗
PubMed1994

Results from a reference laboratory for prenatal diagnosis of sickle cell disorders in Cuba.

A nationwide programme for the prevention of sickle cell (SS and SC) disorders was initiated in Cuba in 1983. Couples at risk were identified by screening pregnant women and the partners of those who carry an abnormal haemoglobin, followed by genetic counselling and the offer of prenatal diagnosis. Prenatal diagnosis was performed in one laboratory, which had carried out 1068 prenatal tests for Hb SS and SC disorders by the end of 1992. The centralization of the service has permitted rapid identification and resolution of problems.

Amniocentesis↗
PubMed1994

Evaluation of the protective activity of 2,3-dimercaptopropanol and sodium 2,3-dimercaptopropane-1-sulfonate on methylmercury-induced developmental toxicity in mice.

The embryotoxic and teratogenic effects of methylmercury in experimental animals have been established by several investigators. The protective activity of 2,3-dimercaptopropanol (BAL) and sodium 2,3-dimercaptopropane-1-sulfonate (DMPS, a chelator used in the treatment of inorganic and organic mercury) on methylmercury chloride (MMC)-induced maternal and developmental toxicity in mice has been evaluated in the present study. BAL and DMPS were administered subcutaneously or by gavage to pregnant mice immediately after a single oral administration of 30 mg MMC/kg given on day 10 of gestation and at 24, 48, and 72 h thereafter. Amelioration by BAL and DMPS of MMC embryo/fetotoxicity was assessed at 15, 30, and 60 mg/kg/day and at 90, 180, and 350 mg/kg/day, respectively. Treatment with BAL did not ameliorate the maternal toxicity or the developmental toxicity of MMC observed in the mouse. In contrast, DMPS at 90, 180, and 360 mg/kg/day significantly reduced the maternal lethality of MMC, whereas treatment with 180 and 360 mg DMPS/kg/day showed significant protective activity against MMC-induced embryotoxicity and teratogenicity. Based on the present findings, DMPS might be a useful chelator against the maternal and developmental toxicity induced by methylmercury.

Abnormalities, Drug-Induced↗
PubMed1994

Enkephalinase inhibition facilitates sexual behavior in the male rat but does not produce conditioned place preference.

The effects of two enkephalinase inhibitors, SCH 34826 and phospho-leu-phe, on male rat sexual behavior and conditioned place preference were evaluated. SCH 34826, administered intraperitoneally, reduced the ejaculation latency to both the first and second ejaculation at a dose of 30 mg/kg. This dose also reduced the first postejaculatory interval. No other effect was obtained with this drug. Phospho-leu-phe, administered intracerebroventricularly, increased mount and intromission latency at doses of 50 and 100 micrograms. A dose of 25 micrograms reduced the latency to the first ejaculation as well as the number of preejaculatory intromissions. The postejaculatory interval was also reduced at this dose. SCH 34826, 100 and 30 mg/kg, and phospho-leu-phe, 25 micrograms, had no effect in the conditioned place preference procedure. These observations seem to suggest that there is no functionally relevant tonic release of enkephalins. Therefore, the effects obtained on sexual behavior may indicate that enkephalins are released before and during the course of sexual activity. The function of such a release could be to facilitate ejaculatory mechanisms in the way found in the present studies. Previous work has shown that ejaculation-induced reward is opioid dependent, further supporting the hypothesis of opioid release during sexual activity. Taken together, these data suggest an important role for opioids, probably enkephalins, in the physiological control of sexual behavior.

Animals↗
PubMed1994

Antibiotic resistance and penicillin tolerance in clinical isolates of group B streptococci.

The aim of this study was to determine the susceptibility patterns of 100 group B streptococcal strains isolated in our hospital and to ascertain tolerance to penicillin by determining quantitative killing curves. We found two strains with intermediate susceptibility to penicillin and eight strains to ampicillin. Seventeen isolates were tolerant to penicillin, with bacterial counts decreasing 2 to 3 log during the first 8 h but still above 10(2) CFU/ml after 24 h. The kinetic study shows that penicillin tolerance is not rare among group B streptococci isolated in our hospital.

Ampicillin Resistance↗
PubMed1994

Anesthetic and hemodynamic effects of single bolus versus incremental titration of hyperbaric spinal lidocaine through microcatheter.

This study examined anesthetic development and hemodynamic changes during two techniques of hyperbaric lidocaine administration through 27-gauge intrathecal catheters for continuous spinal anesthesia in 55 elderly patients undergoing transurethral prostatic resection. Twenty-five patients were randomly assigned to receive hyperbaric lidocaine 5% solution in a single bolus of 75 mg to achieve blockade to approximately T6, and 30 patients to receive hyperbaric lidocaine 2.5% solution in increments of 25 mg to achieve T6 or to a maximum of three doses. Hemodynamic measurements of arterial pressure, heart rate, cardiac output, stroke volume, and ejection fraction were made serially after the induction of spinal anesthesia. Anesthesia failed to spread beyond the sacral region in 9/25 (36%) patients in the single-dose group (SD), but was successfully induced in all patients given titrated doses (TD) at total doses of 50 mg (n = 15) (TD50) and 75 mg (n = 15) (TD75). The mean maximal level of sensory block in all three groups was comparable: T5, T4, and T6 in groups SD, TD50, and TD75, respectively. The onset and progression of sensory block were rapid and similar in the SD and TD50 groups, in contrast to a gradual, stepwise development of block in group TD75. Grade 3 motor block occurred in response to the first dose of 25 mg lidocaine in 7/30 (23%) patients receiving titrated doses, but the overall incidence of leg paralysis did not differ among the three groups by the end of lidocaine dosing. Mean arterial pressure (MAP) decreased significantly relative to baseline in all three groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

Effects of meso-2,3-dimercaptosuccinic acid (DMSA) on methyl mercury-induced teratogenesis in mice.

Methyl mercury has been reported to be embryotoxic and teratogenic in numerous systems such as fish, birds, and mammals. meso-2,3-Dimercaptosuccinic acid (DMSA) has been useful for prevention and treatment of mercury poisoning. In this study, the protective activity of DMSA on methyl mercury-induced embryo/fetotoxicity was evaluated in mice. A series of four DMSA injections was administered subcutaneously to pregnant Swiss mice immediately after oral administration of 25 mg/kg methyl mercury chloride (MMC) given on Day 10 of gestation, and at 24, 48, and 72 hr thereafter. DMSA effectiveness was tested at 0, 80, 160, and 320 mg/kg/day. Oral administration of MMC resulted in a high rate of resorptions and dead fetuses as well as a reduced fetal body weight. Moreover, cleft palate (46.9%) and various developmental variations were found in the positive control group. Treatment with DMSA at 160 and 320 mg/kg/day significantly decreased the embryolethality of MMC, whereas at 320 mg DMSA/kg/day the incidence of skeletal anomalies and cleft palate (2.8%) was also significantly reduced. According to these results, DMSA offers encouragement with regard to its therapeutic potential for pregnant women exposed to methyl mercury.

Animals↗
PubMed1993

Antibiotic susceptibility of group A streptococci: a 6-year follow-up study.

The susceptibility patterns of group A streptococci over the last 6 years in our hospital were determined. Since our last study, carried out in 1987, all isolates have remained very susceptible in vitro to penicillin and all of the other beta-lactam agents tested. We observed resistance to erythromycin, clindamycin, tetracycline, and ofloxacin. The prevalence of erythromycin-resistant group A streptococci did not change appreciably throughout the study period.

Anti-Bacterial Agents↗
PubMed1993

Pulmonary function during and after total hip replacement. Findings in patients who have insertion of a femoral component with and without cement.

Eleven patients who had a femoral component inserted with cement and twenty-three who had a femoral component inserted without cement were studied prospectively for changes in the pulmonary shunt associated with total hip replacement. The levels of oxygen in the arterial blood and the platelet counts were measured preoperatively and each morning for three days after the arthroplasty. Levels of oxygen in the arterial blood were determined intraoperatively, once before and once after the femoral component was inserted. Intraoperative shunt values increased 28 per cent when a femoral component was inserted with cement (p < 0.05), but they did not change when cement was not used. The average postoperative shunt values were higher than the average preoperative shunt values for both groups of patients, but only the values on the second postoperative day after a procedure with cement were significantly higher (p < 0.05). The ability of the patient to tolerate an increase in pulmonary shunt should be assessed when the femoral component is to be cemented during total hip replacement.

Aged↗