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Biomedical subjects

D Alvarez

Publications and source records attributed to D Alvarez.

At least 73 records · Page 4Linked to original sources
PubMed1994

Effect of growth temperature on complement-mediated killing of mesophilic Aeromonas spp. serotype O:34.

Mesophilic Aeromonas spp. strains (serotype O:34) showed sensitivity to complement-mediated killing when they were cultivated at 37 degrees C (serum-sensitive) but not when they were cultivated at 20 degrees C (serum-resistant). These strains produced smooth lipopolysaccharide when they were grown at 20 degrees C and rough lipolysaccharide when cultivated at 37 degrees C. The reason for the resistance to complement-mediated killing could be that C3b is rapidly degraded (possibly because it is bound far from the cell membrane), consequently the lytic complex (C5b-9) is not formed.

Aeromonas↗
PubMed1994

Postprandial vascular response in patients with cirrhosis. Short-term effects of propranolol administration.

Systemic and portal hemodynamic parameters were evaluated in eight cirrhotic patients in basal conditions and after food intake and placebo. Following seven days of oral propranolol administration, hemodynamic parameters were reevaluated in the fasting and postprandial states under similar conditions. Cardiac output and portal blood flow were measured by Doppler technique. Intraobserver variability of repeated measurements was less than 10%. Food intake caused a significant increase of portal blood flow (+28%, P < 0.05). No significant changes were observed in the other hemodynamic parameters studied. Propranolol at doses achieving effective beta blockade (84 +/- 14 mg/day) (mean +/- SD) reduced portal blood flow (-24%, P < 0.05). Food intake caused a significant increase in portal blood flow (+35%, P < 0.05) in propranolol treated patients. However, in absolute values, postprandial portal blood flow during propranolol treatment was significantly lower (986 +/- 402 ml/min) than that obtained after the initial food intake (1214 +/- 537 ml/min, P < 0.05). Placebo administration had no significant hemodynamic effects in either group. This study demonstrates that chronic propranolol administration could protect from portal hemodynamic changes following food intake. Doppler technique is a reliable technique to evaluate changes on portal and systemic hemodynamic parameters during a short period of time in patients with cirrhosis.

Cardiac Output↗
PubMed1994

Diurnal fluctuations of portal and systemic hemodynamic parameters in patients with cirrhosis.

A close temporal relationship between higher levels of portal pressure during the night and the peak incidence of acute variceal bleeding has recently been demonstrated in patients with cirrhosis. Because hemodynamic changes may have a role in triggering this hemorrhagic episode, we measured systemic and portal hemodynamic parameters at 4-hr intervals for 24 hr in 12 cirrhotic patients. These results were compared with those obtained in eight healthy subjects. Cardiac output, femoral and portal blood flows were measured by Doppler technique. In cirrhotic patients, heart rate and mean arterial pressure remained constant throughout the whole study period. A marked and significant increase in portal blood flow (917 +/- 248 ml/min) (mean +/- S.D.) as compared with mesor values (649 +/- 114 ml/min, p < 0.001) was observed at midnight. This effect was accompanied by a mild but significant rise of cardiac output (from 6.5 +/- 0.7 to 6.8 +/- 0.7 l/min, p < 0.01) at 2400 hr. A significant correlation between both hemodynamic parameters was found (r = 0.78, p < 0.01). Cosinor analysis showed a significant (p < 0.05) circadian rhythm for both portal blood flow and cardiac output with an acrophase at 0050 hr. In the healthy subjects group, a significant decrease of mean arterial pressure and heart rate was observed at 2400 hr. Cosinor analysis confirmed the presence of significant rhythm for both hemodynamic parameters. In contrast with cirrhotic patients, no significant changes were observed in portal blood flow and cardiac output in healthy subjects. Our results show that in patients with cirrhosis, maximal increases in portal blood flow occur at night.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Tuberculosis in human immunodeficiency virus-infected children. A family infection.

OBJECTIVE: To study the epidemiologic and clinical features of infection with Mycobacterium tuberculosis in human immunodeficiency virus (HIV)-infected children and their families. PATIENTS AND CLINICAL SETTING: Sixty families of children with HIV infection, children of HIV indeterminate status, and seroreverters underwent follow-up in a comprehensive multidisciplinary program for children and families. METHODS: Infection with M tuberculosis was diagnosed based on a positive Mantoux test result or a positive culture. RESULTS: Mycobacterium tuberculosis infection was diagnosed in seven children (three infected with HIV, three seroreverters, and one uninfected sibling of an infected child) from four families (6%). All infections were detected in the period from March 1990 through January 1992. Six of seven children had a history of exposure to M tuberculosis in an HIV-infected adult (parent) who was an intravenous drug user, homeless, and/or noncompliant with the medical regimen. All HIV-infected children and one seroreverter had pulmonary tuberculosis. One child died of complications of tuberculosis and HIV infection. The M tuberculosis isolated from this child was resistant to isoniazid, rifampin, and streptomycin sulfate. CONCLUSIONS: Tuberculosis is a growing problem among inner-city children born to HIV-infected parents. Children infected with HIV in this study had symptomatic and severe disease with tuberculosis, which reflected the drug susceptibility pattern of M tuberculosis seen in our community.

AIDS-Related Opportunistic Infections↗
PubMed1993

Superior mesenteric artery blood flow in celiac disease.

Measurements of the hemodynamic parameters of the superior mesenteric artery were performed in 18 patients with celiac disease. Ten were studied at the time of diagnosis, when a small bowel biopsy showed a flat mucosa. The remaining eight patients were studied after complete clinical and histological recovery induced by a gluten-free diet. Doppler ultrasound flowmetry was used to measure blood flow in physiological and fasting conditions and after a mixed liquid test meal (Ensure-Plus). The results were compared with those of healthy subjects (N = 7). Mean basal flow was 50% higher in untreated celiac disease patients than in healthy controls and patients with chronic pancreatitis (P = NS). Postprandial mesenteric blood flow was significantly increased (P < 0.002) and delayed in time (P < 0.005) in celiac disease as compared to controls. Successful treatment reduced the mesenteric blood flow in celiac disease to normal values. Our study demonstrates that pathophysiological changes in the small bowel mucosa during the active clinical phase of celiac disease induce an abnormal splanchnic circulation.

Adult↗
PubMed1993

Caffeine reduction in coffee pulp through silage.

Silage tests to study reductions of antiphysiological compounds (caffeine and polyphenols) of fresh coffee pulp during the anaerobic fermentation were done. A concrete silo divided in compartments, with a total capacity of 9 tons of fresh material was utilized. The silage periods ranged between 99-224 days and the following materials were ensiled: 1) coffee pulp, 2) coffee pulp with sugar cane molasses, 3) coffee pulp with a mixture of molasses and ammonia and 4) screw pressed coffee pulp with molasses. Reductions in caffeine, total polyphenols and condensed polyphenols ranged between 13-63%, 28-70% and 51-81% respectively. It was concluded that in the case of coffee pulp, silage presents and ideal method to preserve the material and partially reduce the contents of antiphysiological compounds.

Journal Article↗
PubMed1993

Diagnosis of tuberculous pleurisy using the biologic parameters adenosine deaminase, lysozyme, and interferon gamma.

We compared the parameters pleural adenosine deaminase (PADA, determined in 405 patients), the PADA/serum ADA ratio (P/SADA; 276 cases), pleural lysozyme (PLYS, 276 cases), the PLYS/serum LYS ratio (P/SLYS; 276 cases), and pleural interferon gamma (IFN, 145 cases) regarding their ability to differentiate tuberculous pleural effusions from others. The 405 pleural effusions were classified by previously established criteria as tuberculous (91), neoplastic (110), parapneumonic (58), empyemas (10), transudates (88), or miscellaneous (48). The intermean differences between the tuberculous group and each of the others were statistically significant for all five parameters (p < 0.01 for PLYS and P/SLYS with respect to the empyema group; p < 0.001 otherwise), except for PADA and P/SADA with respect to the empyema group. All the tuberculous pleurisy cases had PADA values of 47 U/L or more, as compared to only 5 percent of the other cases (sensitivity, 100 percent; specificity, 95 percent). P/SADA was above 1.5 in 85.7 percent of tuberculous effusions and 11 percent of the others (sensitivity, 85.7 percent; specificity, 89 percent). PLYS, with a diagnostic threshold of 15 g/ml, had a sensitivity of 85.7 percent and a specificity of 61.6 percent; P/SLYS, with a threshold of 1.1, had a sensitivity of 67.3 percent and a specificity of 90.3 percent; and IFN, with a threshold of 140 pg/ml, had a sensitivity of 94.2 percent and a specificity of 91.8 percent. The lowest misclassification rate was achieved by PADA, with statistically significant differences (p < 0.001) with respect to P/SADA, PLYS, and P/SLYS, but not with respect to IFN. The only significant pairwise correlations among these parameters were between P/SLYS and PADA and between P/SLYS and P/SADA. We conclude that PADA and IFN are useful parameters for early diagnosis of tuberculous pleurisy, and that the other parameters considered have no advantages over PADA and IFN for this purpose (though the high specificity of P/SLYS may be noted).

Adenosine Deaminase↗
PubMed1993

Determination of iron by the Ferrochem II: interference by tuberculostatics.

Iron levels in samples from certain treated tuberculous patients are underestimated by the Ferrochem II analyser. Of the tuberculostatic drugs examined for a possible interference, isoniazid, ethambutol, rifampicin, pyrazinamide and Rifater (a mixture of rifampicin, isoniazid and pyrazinamide), only pyrazinamide and Rifater (due to its pyrazinamide content) were associated with iron levels differing significantly (p < 0.001) from those of controls, with means of -317.2 and -185.6 mumol l-1 for pyrazinamide and Rifater respectively as against 9.91 mumol l-1 for the controls. The negative interference (I) due to pyrazinamide was independent of iron level in the samples but dependent on pyrazinamide concentration in the same (P) (r = 0.9993), I = -0.4380P-0.4276.

Antitubercular Agents↗
PubMed1992

Treatment of massive pulmonary thromboembolism with low intrapulmonary dosages of urokinase. Short-term angiographic and hemodynamic evolution.

Sixteen patients who had massive pulmonary thromboembolism and shock had no history of cardiopulmonary disease. We present an evaluation of the short-term effects of fibrinolytic treatment consisting of intrapulmonary administration of a bolus of 500,000 IU of urokinase followed by infusion of 1 x 10(6) IU into the right auricle over 12 h and subsequent intravenous infusion of heparin. For each patient, the effectiveness of treatment was evaluated by comparing pretreatment angiographic and hemodynamic parameters with those measured 48 h after the start of treatment. The Miller index fell from 22.9 +/- 5.9 to 9.8 +/- 3.3 (p less than 0.001), with a mean improvement of 57.2 percent. All the hemodynamic parameters studied (cardiac output and index, total pulmonary vascular resistance, and systolic, diastolic, and mean pulmonary vascular pressure) also exhibited statistically significant differences between pretreatment and posttreatment values (p less than 0.001 for each parameter), with a mean improvement of over 30 percent in each case. All the patients survived, and in no case did treatment fail; only one patient (6.2 percent) suffered severe hemorrhage. We conclude that this form of administration of urokinase is useful for patients with critical massive pulmonary thromboembolism.

Adult↗
PubMed1991

Noninvasive measurement of portal venous blood flow in patients with cirrhosis: effects of physiological and pharmacological stimuli.

The present study aims to evaluate the usefulness of combined pulse Doppler-real-time ultrasonography as a noninvasive method for the measurement of portal blood flow in man. This measurement technique was performed on 12 healthy subjects and 20 patients with portal hypertension. Ten patients (group 1) were evaluated prior to and after ingestion of a standard meal (Ensure Plus) or placebo. In the remaining 10 patients (group 2), the effects of isosorbide dinitrate (5 mg/SL) administration or placebo were studied. In group 1, food intake caused a significant increase of portal blood flow (from 1038 +/- 539 to 1572 +/- 759 ml/min, P less than 0.02); this effect was due to a significant rise in mean blood velocity (from 18.5 +/- 3.7 to 23.9 +/- 3.9 cm/sec, P less than 0.02). In group 2, isosorbide dinitrate significantly reduced portal blood flow (from 985 +/- 491 to 625 +/- 355 ml/min, P less than 0.05); a significant decline of mean blood velocity (from 18.8 +/- 4.5 to 14.5 +/- 2.5 cm/sec, P less than 0.02) was observed. Placebo administration had no significant hemodynamic effects in either group. Our results suggest that Doppler measurements gave accurate noninvasive estimations of portal blood flow and that this technique may be used to monitor physiological and pharmological stimuli in patients with portal hypertension.

Adult↗
PubMed1989

Role of aggressive intracranial pressure control in management of pediatric craniocerebral gunshot wounds with unfavorable features.

During a 6-year period, 14 consecutive children with penetrating craniocerebral gunshot wounds (GSW) were studied. Eleven patients were comatose on admission. Five had an admission Glasgow Coma Scale (GCS) score of 4 or less and developed clinical signs of brain death within 12 hours despite maximum therapeutic efforts. The remaining six patients, all of whom had three or more of the previously described unfavorable prognostic features, were aggressively managed with prophylaxis and treatment of intracranial hypertension. Intracranial pressure (ICP) was controlled with mechanical hyperventilation, mannitol osmotherapy, pentobarbital, and surgical decompression. Substantial intracranial hypertension occurred for up to 10 days after admission. There were four survivors. Neurobehavioral and intellectual functions were evaluated over a period of 1 to 2 years. Although serious cognitive deficits were noted, all survivors had sufficient functional recovery to warrant aggressive cardiopulmonary resuscitation and measures to control ICP in the management of comatose victims of craniocerebral GSW.

Brain Injuries↗