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Biomedical subjects

M Uribe

Publications and source records attributed to M Uribe.

At least 37 records · Page 2Linked 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

Cholesterolosis is not associated with high cholesterol levels in patients with and without gallstone disease.

High levels of cholesterol have been associated with certain gallbladder disorders such as cholesterolosis and gallstone disease. Furthermore, obesity is considered the main risk factor for cholesterol gallstone disease. We investigated the incidence of cholesterolosis in patients with and patients without gallbladder stones (GS). We reviewed the clinical records of patients with gallstone disease and other gallbladder disorders who had consecutive cholecystectomy during a 5-year period. We recorded demographic data, sex, age, serum cholesterol levels, and body mass index. The diagnosis of cholesterolosis was made macroscopically and microscopically. A total of 636 patients were included in this study: 446 with and 190 without GS. Cholesterolosis was more frequent in patients without GS (p < 0.01). However, hypercholesterolemia occurred more frequently in patients with GS (p < 0.001). Obese patients with GS had higher percentages of cholesterolosis and hypercholesterolemia than did eutrophic patients (p < 0.01 and p < 0.05, respectively). We suggest that cholesterolosis in the human gallbladder is not necessarily associated with gallstone disease and high plasma cholesterol levels.

Adult↗
PubMed1997

Diagnostic value of the copper/zinc ratio in digestive cancer: a case control study.

The aim of this study was to assess the accuracy of the copper/zinc ratio (Cu/Zn ratio) in the evaluation of a large group of patients with digestive cancer compared to gender and age-matched control subjects. A total of 282 patients was studied and separated into three groups: group I (n = 75), patients with digestive cancer, group II (n = 112), patients with benign digestive disease, and group III (n = 95), healthy subjects. Serum levels of copper and zinc were measured by atomic absorption spectrophotometry. The results showed that the serum levels of copper (mg/dL) in patients with digestive cancer (91.6 +/- 27.3, p < 0.05) were significantly higher than in patients with benign digestive disease (75.8 +/- 19.8) or healthy subjects (54.4 +/- 8.9) and the serum levels of zinc (mg/dl) were significantly lower (68.7 +/- 21.9, p < 0.05) compared to benign digestive disease patients (80.1 +/- 18.7) or healthy subjects (100 +/- 11.4 mg/dl). The Cu/Zn ratio was also significantly higher in patients with digestive cancer (1.45 +/- .58, p < 0.05) than those with benign digestive disease (0.95 +/- 0.28) or healthy subjects (0.55 +/- 0.13). Considering a cutoff value of 0.87, the sensitivity of the copper/zinc ratio was 82.2%, with a specificity of 65.7%, a positive predictive value of 45.8% and a negative predictive value of 91.3%. In conclusion, Cu/Zn ratio was found to be considerably higher in patients with digestive cancer compared to age- and gender-matched controls, with a sensitivity of 82.2% that might be useful in the evaluation of suspected malignancy.

Adult↗
PubMed1996

Similar fragmentation and dissolution after extracorporeal shock wave lithotripsy in eutrophic and overweight patients with gallstones.

The aim of this study was to assess the relative importance of overweight and adjuvant treatment with bile acids to obtain fragment dissolution and clearance after biliary extracorporeal shock wave lithotripsy (BESWL), in eutrophic and overweight patients with gallbladder stones. During a 3-year period 103 patients were treated with BESWL. Patients were strictly selected in terms of the number and type of stones. Of the total of 103 patients, 53 were women and 50 men. Mean age was 50.8 +/- 14.3 (range 17 to 86) years. Body mass index was calculated for each patient. All patients underwent BESWL with an electromagnetic device. Medical therapy for stone dissolution included the combination of chenodeoxycholic acid plus ursodeoxycholic acid (50% + 50%), at a total dose of 10-15 mg/day. Of the 103 patients, 45 were eutrophic and 58 were considered overweight. Age was similar in both groups. Number of lithotripsy sessions in eutrophic patients was 1.96 +/- 1.07 and 1.88 +/- 0.84 in overweight patients, but no statistical differences were found. Complete clearance of calculi was observed in more than 50% of the cases after 6 months, and reached 98% after 22 months of therapy in both groups. Total clearance of calculi was similar in patients with single and multiple stones. In conclusion, our results suggest that the time required to obtain complete gallstone clearance after BESWL is similar in eutrophic and overweight patients with gallbladder stones, and also that adjuvant therapy with bile acids plays an important role in gallstone fragment dissolution in these patients.

Adolescent↗
PubMed1996

[Experience of a single center in liver transplantation in adults and children].

Orthotopic liver transplantation (THO) is the treatment of choice for a variety of liver diseases. The national experience before 1993 has been scarce. In November 1993 we started our experience in THO at Clínica Las Condes, as part of a multiorgan transplant program (liver, kidney, pancreas). Until January 1995 we have performed 14 THO in 13 recipients (one retransplantation), of which 5 were in pediatric cases. The recipients range of age fluctuated between 1 and 61 years. In two pediatric cases a liver allograft reduction was performed. Six recipients (46%) required treatment for acute cellular rejection. One recipient had an hepatic artery thrombosis and had to be retransplanted. There was no operative mortality up to 30 days in cases of primary liver transplants. The retransplanted adult recipient, and another pediatric recipient that died from a late recurrence of a hepatoblastoma, accounted for the mortality of this experience. After an average follow up of 10 months, the actual patient survival in 85%. Of the 11 surviving recipients, 9 are in excellent conditions with a very good quality of life. This experience shows that an active liver transplant program in our country can be successful in obtaining results comparable to those published by very experienced foreign transplant centers.

Adolescent↗
PubMed1996

Pathophysiology of cholesterol gallstone disease.

The purpose of the present paper is to review the current knowledge about cholesterol gallstone disease. It is generally accepted that the formation of cholesterol gallstone requires three major pathogenic defects, namely, supersaturation, nucleation and crystal growth as well as disorder of gallbladder motility. The supersaturation is necessary but not sufficient to explain stone formation. It has been suggested that nucleation is the key factor for gallstone formation. However, those three factors are necessary for the formation of cholesterol gallstones, and the presence of just one or two factors does not lead to stones. We also touch briefly on the results from studies performed in Mexico in this area.

Bile↗
PubMed1995

Effects of ursodeoxycholic acid on hemodynamic and renal function abnormalities induced by obstructive jaundice in rats.

UNLABELLED: The mechanism of renal function abnormalities in experimental biliary cirrhosis can be partially explained by the absence of gastrointestinal bile flow, which predisposes to translocation of intestinal endotoxin, a potent renal vasoconstrictor. Since bile acids prevent the absorption of intestinal endotoxins, we aimed to evaluate the effects of ursodeoxycholic acid (UDCA) administration on renal function and hemodynamic abnormalities induced by 1 week of obstructive jaundice in rats. METHODS: Fifty-two rats were used; 30 had ligation of the common bile duct, 22 were sham operated. Bile duct ligated rats were randomly and blindly assigned to receive UDCA (25 mg/kg/day, n = 14) or placebo (n = 16) during 1 week. Sham rats received no treatment. Portal pressure (PP) as well as creatinine clearance (CrCl), urinary sodium (US), and plasma renin activity (PRA) were evaluated. Results are mean +/- SEM, with a significant value of p < 0.05. RESULTS: Portal pressure (10.4 +/- 1.1 vs. 12.1 +/- 0.8 mm Hg) was significantly lower in UDCA than in placebo-treated rats. ALT serum levels were also significantly lower in bile duct ligated rats receiving UDCA (77.3 +/- 28 IU/L) than in placebo-treated rats (162 +/- 65 IU/L). US (1.1 +/- 0.5 vs. 2.1 +/- 0.3 mEq/24 h) was significantly lower and PRA (6.0 +/- 2.6 vs. 1.9 +/- 1.0 ng Ang 1/mL/h) higher in bile duct ligated than in sham-operated rats. No differences were found between UDCA or placebo-treated bile duct ligated rats. CrCl was similar between sham (0.39 +/- 0.12 mL/min/100 g BW) and UDCA (0.32 +/- 0.16) but significantly lower in placebo-treated (0.28 +/- 0.07) than sham-operated rats (p < 0.05). CONCLUSION: UDCA administration had very mild effects on renal function abnormalities induced by experimental obstructive jaundice in rats. However, portal hypertension and biochemical abnormalities were partially improved.

Analysis of Variance↗
PubMed1995

Gallstone composition in Mexican patients.

Prevalence of gallstone disease in Mexico is similar to that found in some European countries. Patients from those industrialized Western countries primarily develop cholesterol gallstones; however, we do not have information related to the chemical composition of gallstones in the Mexican population. The aim of this study was to determine the physiochemical characteristics of gallstones from patients undergoing surgery for symptomatic cholelithiasis. We analyzed gallstone specimens from 59 patients (17 male and 42 female) from five Mexican states and Mexico City by X-ray diffraction. The chemical analysis revealed that 71.2% of the patients had stones of mixed composition. We concluded that the chemical composition of gallstones found in Mexican patients is similar to that found in patients from other Western countries.

Adult↗
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↗
PubMed1995

[Phase II trial with navelbine + cisplatin + etoposide in the treatment of inoperable non-small cell lung carcinoma].

40 patients with advanced non-small cell lung cancer not previously treated were included in a study at phase II with vinorelbine 20 mg/Sq.m days 1 and 8, etoposide 60 mg/sq.m days 1-3 and cisplatin 75 mg/sq.m day 1 each 28 days for 6 cycles. There were 31 men and 9 women, being the average age of 54 years, with "performance Status" grade 0-2. All of them could be evaluated for toxicity and 31 for responsiveness. 10 patients were in stage IIIb and 21 at stage IV. 42% of objective responses were obtained and an overall survival of 9 months, which justifies further studies.

Adult↗
PubMed1995

[Hematological serological valves, and organ weight in adult Sprague-Dawley rats].

Sprague-Dawley rats are frequently used in experiments and their normal hematological, serologic and anatomical parameters are not easily available. The aim of this study was to measure these parameters in adult Sprague-Dawley rats. Twenty-four rats (12 males) whose weight ranged between 200 and 300 g, raised at the Instituto de Salud Pública in controlled environmental conditions and fed with pellets were studied. After a 24 h fast, animals were anesthetized with Droperidol and Ketamine, and after obtaining a cardiac blood sample, sacrificed by exsanguination. Most organs were withdrawn and weighed. Mean values for blood glucose, calcium, amylase, total proteins, cholesterol, AST, ALT, bilirubin, alkaline phosphatases, electrolytes and complete blood count were determined. Heart, lung, pancreas, kidney and testicle mean weight was also calculated. Male and female rats had significant differences in packed red cell volume, white blood cell count and hemoglobin.

Animals↗
PubMed1994

Esophageal cancer after mediastinal irradiation.

The authors report 4 patients, without a history of tobacco or alcohol abuse, who developed squamous cell carcinoma of the esophagus secondary to mediastinal irradiation. Carcinoma of the esophagus developed in 3 women 8-11 years after mediastinal radiotherapy for breast cancer and in a man 9 years after mediastinal radiotherapy for Hodgkin's disease. Three patients underwent resection, with intrathoracic anastomosis in 2 and cervical in 1. No fistulae were observed despite the presence of esophageal fibrosis. No mediastinal lymph node was metastatic. Patients survived 7, 16, and 26 months, respectively, after resection. This study confirms the concept of radiation-induced carcinogenesis. We conclude that patients with dysphagia and a history of previous mediastinal radiotherapy should undergo repeated endoscopy for biopsy.

Aged↗
PubMed1994

A ten-year experience with hepatic resection in 338 patients: evolutions in indications and of operative mortality.

OBJECTIVE: To report changes in indications for, and operative mortality of, elective hepatic resection during the 10 year period 1980-1989. DESIGN: Retrospective study. SETTING: District hospital. SUBJECTS: 338 consecutive patients who underwent elective hepatic resection. INTERVENTIONS: During the first five years (1980-1984) 99 resections were done, 10 through a right thoracoabdominal incision, and the hepatic pedicle was clamped in 6. During the period 1985-1989 239 resections were done, only 7 (3%) through a thoracoabdominal incision, and the hepatic pedicle was occluded in 197 (82%). MAIN OUTCOME MEASURES: Changes in indications for operation and operative technique, and mortality. RESULTS: Indications for resection in the first period were: benign lesions (n = 39), primary hepatic cancer (n = 30-15 had hepatocellular carcinoma associated with cirrhosis), and metastatic disease (n = 30). Six patients died, five from uncontrollable bleeding during operation. Indications during the second half were: benign lesions (n = 105, 44%), primary hepatic cancer (n = 87, 36%-62 (29%) had hepatocellular carcinoma associated with cirrhosis), and metastatic disease (n = 47, 20%). There was only 1 death during operation (air embolism), and 9 cirrhotic patients died during the postoperative period. CONCLUSIONS: More hepatic resections are being done and the indications are changing, with more patients with cancer and benign tumours being operated on; increasing use of pedicle occlusion has resulted in a significant decrease in uncontrollable operative bleeding; and mortality is still related to the presence of associated cirrhosis.

Adolescent↗
PubMed1993

Prevalence of gallstone disease in Mexico. A necropsy study.

The prevalence of gallstone disease in Mexico was investigated by studying a sample of 21,446 necropsies performed at the Department of Pathology of the General Hospital of Mexico City during a 35-year period (1953-1988). For each decade, 1000 necropsy cases were randomly selected. The crude prevalence of gallstone disease was 14.3%, 8.5% for males and 20.4% for females. The age groups ranged from 20 to more than 80 years old; the age-standardized prevalence for males was 5.6% and for females 16.2%. These rates are intermediate between those found in Chile and some African countries, comparable to some European studies, and less than those found in Mexican-Americans. No significant trend in the prevalence of gallstone disease was found when the different decades were compared.

Adult↗
PubMed1993

Esophageal cancer after mediastinal irradiation.

The authors report 4 patients, without a history of tobacco or alcohol abuse, who developed squamous cell carcinoma of the esophagus secondary to mediastinal irradiation. Carcinoma of the esophagus developed in 3 women 8-11 years after mediastinal radiotherapy for breast cancer and in a man 9 years after mediastinal radiotherapy for Hodgkin's disease. Three patients underwent resection, with intrathoracic anastomosis in 2 and cervical in 1. No fistulae were observed despite the presence of esophageal fibrosis. No mediastinal lymph node was metastatic. Patients survived 7, 16, and 26 months, respectively, after resection. This study confirms the concept of radiation-induced carcinogenesis. We conclude that patients with dysphagia and a history of previous mediastinal radiotherapy should undergo repeated endoscopy for biopsy.

Aged↗