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Biomedical subjects

L Guevara

Publications and source records attributed to L Guevara.

At least 19 recordsLinked to original sources
PubMed1998

Risk factors for gallstone disease in Mexicans are similar to those found in Mexican-Americans.

According to epidemiological studies, gallstone disease is a very common disease in Mexican-Americans and Mexicans. However, the major risk factors for cholelithiasis in Mexicans have not been identified. We designed a case-control study in a group of Mexican subjects with and without gallstone disease confirmed by ultrasound. These subjects were prospectively studied over a three-year period. Clinical and epidemiological data were collected by means of a questionnaire. A total of 1500 subjects were included in this study: 1000 with and 500 without gallstone disease. The major risk factor in both men and women was body mass index [odds ratio (OR) 1.64 and 1.96, respectively; P < 0.008 and 0.001]. In addition, parity was an important factor in women (OR 2.17, P < 0.001), whereas age was associated with gallstone disease in men (OR 1.43, P < 0.001). We found that body mass index, parity, and age were the principal risk factors for gallstone disease in this group of Mexican subjects. These results are similar to those found in Mexican-American populations.

Adult↗
PubMed1998

Beneficial effect of carbohydrate maldigestion induced by a disaccharidase inhibitor (AO-128) in the treatment of chronic portal-systemic encephalopathy. A double-blind, randomized, controlled trial.

BACKGROUND: The most widely used treatment of portal-systemic encephalopathy (PSE) is the administration of oral, non-absorbable disaccharides. Theoretically, the inhibition of intestinal disaccharidases should induce malabsorption of disaccharides and increase delivery of undigested carbohydrates to the colon, thus stimulating the effects of lactulose and other non-absorbable disaccharides (that is, lactitol and lactose). AO-128 is an N-substituted derivative of valeolamine, an aminocyclitol that selectively inhibits intestinal disaccharidases. This study was performed to investigate whether AO-128 could be used as adjuvant therapy for the treatment of mild PSE in cirrhotic patients. METHODS: A double-blind, randomized, controlled trial was performed in 35 cirrhotic patients with PSE. Patients were given a 2-week treatment consisting of AO-128 (2 mg three times daily) or an identical placebo. The following features of PSE syndrome were assessed in a semiquantitative fashion before and after I and 2 weeks of therapy: mental state, asterixis, number connection test (NCT), venous blood ammonia concentration, electroencephalogram (EEG), and overall PSE index (PSEI). More patients receiving AO-128 than patients receiving placebo showed >40% improvement in the PSEI (83% versus 35%; P < 0.05). The mean stool pH decreased from 5.8+/-0.3 to 5.5+/-0.3 (P < 0.004) after AO-128 treatment, whereas no changes were observed in the placebo group. The EEG and nitrogen balance did not show significant changes in any of the two groups. A significant improvement was seen in the NCT performance after AO-128 (from grade 2.0+/-1.04 to grade 1.25+/-0.87; P < 0.05). Seven patients treated with AO-128 developed diarrhea, as compared with none in the placebo group (P < 0.05). CONCLUSION: These results suggest that AO-128 may be useful in the treatment of PSE, although further studies are required to establish the benefit of AO-128 and determine adequate individual doses.

Cyclohexanols↗
PubMed1997

Bull effect on the reproductive performance of mature and first calf-suckled Zebu cows in the tropics.

This experiment was designed to determine if continuous bull exposure of heifers 2 wk post partum to a first calf (30 to 36 m old) or mature (42 to 72 m old) Zebú Brahman suckled cows reduces the interval to first estrus and the number of days open. Post partum first calf cows were randomly assigned to be exposed continuously to epidectomized bulls with surgical ablation of the dorsal ligament of the penis (Group 35 FBE, n = 25) or not exposed to bulls (Group FNE, n = 22). Post partum mature cows were likewise assigned to be continuously exposed (Group MBE, n = 24) or not exposed to bulls (Group MNE, n = 25). Milk samples were collected twice a week for progesterone assays to determine resumption of ovarian cyclic activity. All the cows were artificially inseminated for 120 d while in their respective treatment groups. The first postpartum estrus percentages were </=60 d, 41.9%; > 60 < 90 d, 24.4%; and > 90 d, 33.7%. The interval to first estrus f-or Groups FBE and FNE was 75.4 and 104.2 d, respectively, and differed significantly (P < 0.01). For Groups MBE and MNE the interval to first estrus was 76.3 and 95.0 d, respectively (P < 0.05). The number of open days for Groups FBE and FNE was 77.3 and 114.9, respectively (P < 0.01); while for Groups MBE and MNE it was 73.0 and 98.6 d, respectively (P < 0.01). The results of the present study indicate that introduction of bulls to first calving cows or mature Zebú Brahman cows after parturition provides a practical and economical option for reducing the extended post partum anestrus interval and days open under tropical conditions.

Journal Article↗
PubMed1995

Portal-systemic encephalopathy and gastrointestinal bleeding after cardioselective beta-blocker (metoprolol) administration to patients with portal hypertension.

The use of the non-selective beta-blocker propranolol has been widely recommended to prevent gastrointestinal bleeding in patients with portal hypertension. We conducted a prospective, randomized controlled trial of metoprolol, a selective beta-blocker for prevention of gastrointestinal bleeding from portal hypertension in 29 non-selected patients with liver disease and previous gastrointestinal bleeding. Fifteen patients received placebo treatment for 40 +/- 18 months and 14 patients received metoprolol for 31 +/- 17 months. A sustained reduction in resting pulse was observed in those patients treated with metoprolol. There was no significant difference in acute re-bleeding episodes between the two groups. Of the 14 patients treated with metoprolol, three (21%) re-bled, all three requiring blood transfusion. Four (26.5%) of the 15 patients treated with the placebo re-bled, two cases with acute bleeding and the remaining two cases presented a positive stool guaiac test. All cases who bled during the metoprolol therapy required exclusion from the trial, and surgical procedures or sclerotherapy as well. After both metoprolol or placebo treatments, similar deterioration of standard liver function tests was observed. Further, at the end of the trial, 11 patients on metoprolol (78%) and four of the patients treated with the placebo (27%) required treatment for clinical portal-systemic encephalopathy (p < 0.01). The risk of poor sympathomimetic response after cardioselective beta 1-blocker during acute bleeding episodes and the appearance of hepatic encephalopathy deserve further investigation. The selective beta-blocker metoprolol seems to be an inadequate choice to prevent gastrointestinal re-bleeding in patients with portal hypertension.

Adrenergic beta-Antagonists↗
PubMed1990

Role of the distal splenorenal shunt in management of variceal bleeding in Latin America.

In the early 1970s, we began to perform selective shunts on a regular basis for the treatment of portal hypertension. In a 15-year period, 177 patients (155 with liver cirrhosis) were treated with 3 kinds of selective shunts: the Warren shunt (128 patients) the end-to-end splenorenal shunt (29 patients), and the splenocaval shunt (20 patients). One hundred sixty-seven of the procedures were elective. Operative mortality was 14%, and survival for the Child's class A group was 75% at 1 year, 69% at 5 years, and 65% at 15 years. Incapacitating encephalopathy was observed in 7% of the patients, rebleeding in 6%, and shunt thrombosis in 6%. Postoperative portal vein alterations included reduced venous diameter (13%) and thrombosis (21%). Experience with the Warren shunt in schistosomiasis, a disease in which normal liver function is the rule in Latin American countries, is discussed. We believe that, when feasible, the selective shunts are the treatment of choice for portal hypertension in Latin American countries.

Adolescent↗
PubMed1988

Ten years of selective shunts for hemorrhagic portal hypertension.

Selective portosystemic shunts have been performed in our hospital since 1973 for the treatment of variceal bleeding secondary to portal hypertension. We report our experience in 139 selective operations performed in a 10-year period (1973 to 1983). One hundred thirty patients underwent elective nine underwent emergency surgery. Eighty-five patients were classified in the A functional group of Child, 42 in group B, and 12 in group C. The overall mortality rate in the emergency group was 44% and in the elective group, 13%. Ascitis and transitory hepatic failure were the most common postoperative complications. The long-term follow-up clinical encephalopathy rate was 16%. The survival rate according to the Kaplan-Meier survival analysis was 80% at 2 years, 68% at 5 years, and 67% at 10 years.

Adolescent↗
PubMed1987

Lactitol, a second-generation disaccharide for treatment of chronic portal-systemic encephalopathy. A double-blind, crossover, randomized clinical trial.

A double-blind crossover trial was performed to test the therapeutic usefulness and safety of lactitol, a beta-galactoside sorbitol, against lactose in 18 patients with chronic portal-systemic encephalopathy (PSE). The study included four periods: two for washout and two for lactitol and lactose administration. During washout periods, which lasted two weeks each, patients were stabilized with neomycin plus milk of magnesia. Lactitol and lactose were administered during four weeks each. Ten patients were randomly assigned to receive lactose (group A) and eight patients to receive lactitol (group B) first. PSE parameters, ie, mental state, number connection test performance, asterixis and blood ammonia levels were assessed fortnightly. Electroencephalographic tracings and stool pHs were evaluated at the end of each study period. After the first administration of lactose and lactitol, no statistically significant differences in PSE parameters were found. At the same stage, a significant stool acidification (P less than 0.05) was detected. It is concluded that lactitol seems to be safe and efficacious in treating patients with chronic PSE.

Clinical Trials as Topic↗
PubMed1983

A study with quinfamide in the treatment of chronic amebiasis in adults.

Quinfamide, a luminal amebicide, is a dichloroacetyl quinolol used to treat chronic and subacute intestinal amebiasis. Several previous dose-ranging studies have indicated that quinfamide is effective in a total dose of 300, 600, or 1,200 mg. The present study was undertaken to determine the efficacy of 100- and 200-mg doses, each given three times daily. A cure rate of 100% was found at a dosage of 100 mg/8 hr and of 93.3% at 200 mg/8 hr. These results indicate that quinfamide is an effective luminal amebicide at the doses studied.

Adolescent↗
PubMed1983

Standard and higher doses of bromocriptine for severe chronic portal-systemic encephalopathy.

In a single-blind, cross-over fashion we assessed the therapeutic value of the dopamine agonist bromocriptine at doses of 15 and 20 mg/day plus cleansing enemas, versus the vigorous standard treatment of neomycin 6 g/day plus cleansing enemas. We studied four patients with severe chronic portal systemic encephalopathy. All the patients presented elevated prolactin levels. During the study the following parameters were assessed: mental state, number connection test times, frequency of asterixis, EEG, blood ammonia, and serum prolactin levels. In all but one patient, portal systemic encephalopathy parameters improved during the standard therapy, as opposed to both bromocriptine periods. During the period with 30 mg/day of bromocriptine all four patients developed precoma, although later one patient improved. Serum prolactin levels were rapidly suppressed during both bromocriptine periods. Prolactin levels did not correlate with changes in mental state. In patients with severe portal systemic encephalopathy, treatments with 15 and 30 mg of bromocriptine plus cleansing enemas were no better than the standard therapy.

Bromocriptine↗
PubMed1981

Survival and quality of life after selective portasystemic shunts.

Selective portasystemic shunts were performed in 55 consecutive patients; 27 underwent end-to-end selective renosplenic shunt, 18 distal splenorenal shunt and 10 splenocaval shunt. Thirty-one patients were in Child's class A, 18 were in class B and 6 in class C. Hospital mortality for the whole group was 16 percent and occurred less frequently in class A than in class B and C patients. Five year predicted survival for the whole group was 59 percent. At the same period of follow-up, class A patients had a higher survival rate than those in class B and C (83 percent versus 36 percent; p < 0.01). No striking difference in 5 year survival was evident in alcoholics and nonalcoholics (52 percent versus 61 percent). After surgery, long-term portasystemic encephalopathy and bleeding were noted in 2 of 36 survivors. For class A patients, selective portal shunts offer an adequate and relative safe method for decreasing mortality due to variceal bleeding.

Adolescent↗
PubMed1980

Treatment of chronic portal-systemic encephalopathy with lactose in lactase-deficient patients.

A controlled cross-over clinical comparison of lactose (50 g twice a day) versus neomycin (3 g/day) plus milk of magnesia, was carried out in ten cirrhotic patients with chronic portal-systemic encephalopathy and documented lactase deficiency. Serial semiquantitative assessments were done including: mental state, asterixis, number connection test, electroencephalogram, and blood ammonia levels. No patient developed deep coma while ingesting either lactose or neomycin plus milk of magnesia. However, a significant improvement of mental state, asterixis, number connection tests, and electroencephalograms was evident during lactose therapy. apart from mild diarrhea and bloating, no severe side effects were noticeable during lactose treatment. Based on these results, we propose lactose as a valuable alternate treatment of portal-systemic encephalopathy in lactase-deficient populations.

Chronic Disease↗
PubMed1979

Treatment of chronic portal systemic encephalopathy with bromocriptine: a double-blind controlled trial.

A randomized double-blind clinical comparison of bromocriptine, a new dopamine agonist, and placebo was performed on 7 cirrhotic patients with chronic portal systemic encephalopathy (PSE). Before given either medication, patients were stabilized with a standard treatment (neomycin and cathartics). Serial semiquantitative assessments were done, including mental state, asterixis, number connection test, electroencephalogram, and ammonia blood levels. Three patients developed signs of precoma while ingesting both placebo and bromocriptine. Two patients experienced precoma only with placebo, and another patient only while taking bromocriptine. One patient remained awake throughout the study. All patients responded initially to neomycin and cathartics. Bromocriptine proved not to be significantly superior to placebo and was always inferior to standard treatment. During treatment with bromocriptine, 3 patients experienced constipation. This may be partially responsible for the ineffectiveness in the treatment of PSE.

Ammonia↗