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Biomedical subjects

M Uribe

Publications and source records attributed to M Uribe.

At least 19 recordsLinked to original sources
PubMed2006

Adiponectin, structure, function and pathophysiological implications in non-alcoholic fatty liver disease.

Obesity is a major risk factor for the development of the metabolic syndrome, a cluster of diseases including insulin resistance, type 2 diabetes, dyslipidemia, hypertension, microalbuminuria, atherosclerosis, and non-alcoholic steatohepatitis. On the other hand, it is now generally accepted that adipose tissue acts as an endocrine organ producing a number of substances with an important role in the regulation of food intake, energy expenditure and a series of metabolic processes. Adiponectin is a recently discovered hormone produced exclusively by adipocytes. In fact, adiponectin is considered currently as a major factor in obesity-related insulin resistance and atherosclerosis. This new hormone differs from other adipocytokines in that its production and concentrations are actually decreased in insulin resistant subjects. The aim of this review is to summarize the current knowledge about the chemistry and physiology of adiponectin and to discuss its implications in the pathophysiology and potential treatment of insulin resistance and non-alcoholic fatty liver disease.

Adiponectin↗
PubMed2005

ABO-incompatible liver transplantation: a new therapeutic option for patients with acute liver failure in Chile.

Different ways have been suggested to expand donor numbers for liver transplantation. Transplantation using ABO-incompatible hepatic grafts has recently been a controversial issue due to the high risk of hyperacute rejection mediated by preformed anti-ABO antibodies. We report three patients with acute liver failure who were transplanted with ABO-incompatible livers: A to O in two patients and A to B in one case. We used pre- and posttransplant total plasma exchange, splenectomy, and triple immunosuppression. All three patients are alive; one graft was lost, probably secondary to thrombotic microangiopathy with low isohemagglutinin titers of 1:8. One patient developed acute cellular rejection that was reversed with a bolus of methylprednisolone. No antibody-mediated rejection occurred. Financial and infectious considerations have to be considered. In our series, the final liver transplantation cost was higher than average for acute liver failure. Plasmapheresis has the highest cost of all the additional procedures. ABO-incompatible liver transplantation, because of the splenectomy it requires, has been associated with more infections due to encapsulated organisms. However, with splenectomy in our three patients, none had infections due to these bacteria. In our country, we do not consider ABO-incompatible liver transplantation as a first-line option, except for highly selected patients.

ABO Blood-Group System↗
PubMed2005

Combined liver and kidney transplantation in a multicenter transplantation program in Chile.

INTRODUCTION: Combined liver and kidney transplantation (CLKT) is an exceptional therapeutic procedure limited to a few diseases with advanced compromise of these organs. Hyperoxaluria type I and polycystic disease are the most frequent indications. The aim of this article was to report our indications and results of CLKT in a multicenter transplantation program in Chile. MATERIAL AND METHODS: Our Excel database was reviewed to select patients who were treated with CLKT between 1993 and July 2004. RESULTS: Among 242 liver transplantations (LT) and 48 kidney transplantations (KT), 7 were CLKT, representing 2.8% of LT and 14.5% of KT. Four patients were women and 3 were male of average age 46.8 years. One patient was a child. Most frequent indications were chronic renal failure associated with terminal liver disease and polycystic disease. One patient needed liver retransplantation due to hepatic vein thrombosis. One patient had a biliary fistula and another had a urinary fistula, treated conservatively. Acute liver rejection took place in 3 cases, 1 of which required antibodies. Two patients died, 1 due to aspergillosis and the other due to vascular complications in the transplanted liver. Actuarial survival rates were 71.4% at 1 and 5 years. Chronic renal failure is not a contraindication to LT. CONCLUSION: CLKT is an acceptable option for these patients.

Child↗
PubMed2005

Pediatric liver transplantation: ten years of experience in a multicentric program in Chile.

Liver transplantation is the only treatment for patients with terminal acute and chronic diseases. Liver transplantation was started in Chile in 1985; our pediatric program began in 1993. The aim of this paper work was to present our experience from 1993 through 2004. One hundred and thirty two orthotopic liver transplants (OLT) were performed in children of mean age 5 years and median age 4 years (8 months to 15 years). The most frequent indications were biliary atresia, (43.1%) and acute liver failure (ALF; 20.4%), whose frequent cause was unknown but viral hepatitis A was the second one. A complete liver was transplanted in 59 patients, reduced in 39, split in one, and as an auxiliary liver in another one. Living related liver transplantation was performed in 32 cases (24.2%), of which thirty included segments II and III, and two, a right liver. A terminal arterial anastomosis was performed in 102 (77.2%) recipients and a graft interposition in 32 patients (24.2%). In 16 cases, biliary reconstruction was performed through an enterobiliary anastomosis. Immunosuppression included cyclosporine (Neoral), steroids, and azathioprine with conversion to tacrolimus (Prograf) as indicated. Rejection episodes, which were always biopsy-proven, were treated either with methylprednisolone or with antibodies. Biliary complications were the most frequent (21.4%) and the second cause was vascular complications (13%). Sixty-six patients suffered an acute rejection episode. Actuarial graft survival was 81.3% at 1 year and 72% at 5 years, while actuarial graft survival for ALF was 75.9% at 1 year and 67.8% at 5 years. Our results are comparable to those reported by most international groups.

Adolescent↗
PubMed2005

Living related liver transplantation. Why this option has been discarded in a pediatric liver transplant program in Chile.

Living related living transplantation (LRLT) has opened new possibilities for planning transplantation in better conditions for children with emergency situations and chronic liver diseases. Since we began the LRLT program in 1999, we have performed 57 pediatric liver transplants, 17 (29.8%) using living related donors (LRD). The aim of this study was to analyze the reasons why LRD were discarded as a therapeutic option. All pediatric patients were prospectively included in our Microsoft Excel database that was reviewed for obtaining information about causes why the LRLT could not be done. LRLT was proposed in 28 cases and performed in 17 (60.7%). The reasons for LRD rejection were: parent's fear of surgical complications in four cases; drug abuse in two; a mother without family support; medical reasons in two; and only one, due to anatomical reasons and in one case, cadaveric graft transplantation was performed while completing the father's evaluation. From these eleven cases, the indications for liver transplant were acute liver failure (ALF) in seven, biliary atresia in three, and Alagille syndrome in one. Nine were transplanted with cadaveric organs, but two patients with ALF died awaiting a liver. Efforts should be made to clarify the advantages and the disadvantages of LRD in each case, allowing parents to make a free, well-informed decision.

Attitude to Health↗
PubMed2005

Autoimmune rheumatic diseases in the intensive care unit: experience from a tertiary referral hospital and review of the literature.

Autoimmune rheumatic diseases (AIRD) are not uncommon in the general population and up to one third of hospitalized patients with AIRD may need admission to intensive care unit (ICU). This paper describes the causes of admission, the clinical features and outcome of 24 AIRD patients admitted to a medical ICU from a third level hospital. Thirteen patients had systemic lupus erythematosus (54.2%), three rheumatoid arthritis (12.5%), three pulmonary renal syndrome (12.5%), two dermatopolymyositis (8.3%), two scleroderma (8.3%) and one antiphospholipid syndrome (4.2%). The main causes for ICU admission were rheumatic disease flare-up (37.5%), infection (37.5%) and complications derived from rheumatic disease (29.1%). Mortality during ICU stay was 16.7% (four patients). Excluding shock requiring vasopressor support, no statistical difference was found between survivors and nonsurvivors; although there was a trend to higher test severity scores (APACHE II, ODIN) in nonsurvivors. Our results reveal a lower mortality rate in AIRD patients admitted to the ICU than reported previously. Severity scores such as APACHE II are predictors of mortality in patients with AIRD in the ICU.

Adolescent↗
PubMed2004

Triple combination of thymalfasin, peginterferon alfa-2a and ribavirin in patients with chronic hepatitis C who have failed prior interferon and ribavirin treatment: 24-week interim results of a pilot study.

Despite steady progress in antiviral treatment for patients with chronic hepatitis C virus (HCV), many patients still have detectable serum HCV RNA levels by the end of interferon-based treatment and are known as virological non-responders. Re-treatment of these patients not responding to previous therapy remains challenging. Studies of the dynamics of the HCV population show a marked decline in new cases since 1996; however, the relative proportion of non-responders is expected to increase over time and, similarly, the number of patients eligible for first-line treatment is expected to decrease. The current standard of care for treatment involves the use of pegylated interferons in combination with ribavirin. However, many difficult-to-treat groups still have low response rates. Newer combinations are being investigated to optimize chances of attaining a sustained response in these groups: one such triple therapy regimen is peginterferon alfa-2a, ribavirin and thymalfasin, which was given to 23 previously non-responder patients. Viral response was 60.8% at week 12 and 47.8% at week 24. These preliminary results encourage further evaluation of this promising combination.

Adult↗
PubMed2004

Triple combination of thymalfasin, peginterferon alfa-2a and ribavirin in patients with chronic hepatitis C who have failed prior interferon and ribavirin treatment: 24-week interim results of a pilot study.

Despite steady progress in antiviral treatment for patients with chronic hepatitis C virus(HCV), many patients still have detectable serum HCV RNA levels by the end of interferon-based treatment and are known as virological non-responders. Re-treatment of these patients not responding to previous therapy remains challenging. Studies of the dynamics of the HCV population show a marked decline in new cases since 1996; however, the relative proportion of non-responders is expected to increase over time and, similarly, the number of patients eligible for first-line treatment is expected to decrease. The current standard of care for treatment involves the use of pegylated interferons in combination with ribavirin. However, many difficult-to-treat groups still have low response rates. Newer combinations are being investigated to optimize chances of attaining a sustained response in these groups: one such triple therapy regimen is peginterferon alfa-2a, ribavirin and thymalfasin, which was given to 23 previously non-responder patients. Viral response was 60.8% at week 12 and 47.8% at week 24. These preliminary results encourage further evaluation of this promising combination.

Adjuvants, Immunologic↗
PubMed2003

Outcomes of orthotopic liver transplantation in Chile.

Our liver transplant program was started in 1993 in a private clinic and a public hospital. Thereafter, a rapid increase in adults and pediatric candidates for this therapeutic option lead to this analysis of results in 165 orthotopic liver transplants (OLT) in 143 patients between November 1993 and December 2002. Seventy-four OLT were performed in 66 adult patients and 91 in the pediatric group. Liver grafts came from cadaveric donors in 145 cases (74 adults and 71 children). The technique of living-related donor was utilized in 20 pediatric cases. Main indications for OLT in the adult group were HCV cirrhosis, primary biliary cirrhosis; biliary atresia and acute liver failure were the indications in pediatric patients. Retransplantation was needed for 23 patients, including 9 adults and 14 children. The most frequent causes of death were sepsis, graft primary nonfunction, and vascular complications. Actuarial survivals at 1 and 5 years were 80.7% and 72.6% for the adult group and 82% and 74.8% for the pediatric group, respectively. Our results are comparable to those published by large, experienced, international centers, with much better financial support.

Adolescent↗
PubMed2003

Epidemiology and results of liver transplantation for acute liver failure in Chile.

Acute liver failure (ALF) is a severe, life-threatening condition associated with a high mortality rate. The objective of this study is to present the experience of a Chilean liver transplant program with orthotopic liver transplantation (OLT) for ALF. All patients with the diagnosis of ALF evaluated in our program between January 1995 and May 2003 were included in the analyses of etiology and outcomes. Candidates for OLT activated on a national waiting list were transplanted with cadaveric or living-related donor (LRD) organs. Twenty-seven patients age 1 to 19 years (median, 7.4 years) were transplanted at a median weight of 30.7 kg including 17 cadaveric and 10 with LRD livers. Most frequent etiologies were hepatitis A in 10 cases (37%) and unknown in 12 (48.1%). One donor experienced superficial phlebitis. Four patients were retransplanted (14.8%). Twenty patients are alive with 1- and 5-year survival rates of 74.1% At a median follow up of 34 months (range = 2 to 120). Seven patients died due to sepsis, multiorganic failure, graft primary nonfunction, intracranial hemorrhage, and intraoperative cardiac arrest. This experience revealed results comparable to international reports, allowing survival of patients destined to die.

Adolescent↗
PubMed2001

Zinc salts precipitate unconjugated bilirubin in vitro and inhibit enterohepatic cycling of bilirubin in hamsters.

BACKGROUND: We have evidence for enterohepatic cycling of bilirubin experimentally and in vivo in humans. This study was designed to investigate whether Zn salts might inhibit such cycling of bilirubin. MATERIALS AND METHODS: Micellar bile salt solutions with unconjugated bilirubin were prepared, appropriate concentrations of Zn salts were added, and unconjugated bilirubin precipitation was measured. Hamsters and Wistar rats were fed a chow diet or a chow diet enriched with 1% ZnSO4, and bilirubin secretion rates were monitored. RESULTS: Unconjugated bilirubin was precipitated maximally (90%) after a 10-min incubation with 5 mM Zn salts in the pH range of 6.8-9.0. In control hamsters, total bilirubin secretion rates into bile were 36.0 +/- 2.8 nmol h(-1) 100g(-1) body weight, whereas they were 25.0 +/- 3.3 nmol h-1 100(-1) g in the ZnSO4 group (P < 0.05). CONCLUSIONS: Zn salts that flocculate at physiological pH adsorb unconjugated bilirubin almost completely from unsaturated micellar BS solutions. In addition, Zn salts administered orally suppress biliary bilirubin secretion rates in hamsters. These findings suggest that the administration of Zn salts may inhibit the enterohepatic cycling of unconjugated bilirubin in humans who are predisposed to pigment gallstone formation due to diet, disease or drugs.

Animals↗
PubMed2001

Fish oil (n-3) polyunsaturated fatty acids beneficially affect biliary cholesterol nucleation time in obese women losing weight.

It has been reported that intake of (n-3) polyunsaturated fatty acids (PUFA) reduces the risk of coronary heart disease and decreases biliary cholesterol saturation in the bile of gallstone patients. We investigated the effect of n-3 PUFA on cholesterol saturation index (CSI) and nucleation time (NT) in obese subjects who were losing weight. This was a double-blind, placebo-controlled clinical trial. Obese women (n = 35) with a body mass index (BMI) > or = 30 kg/m(2), with no prior history of gallstones or cholecystectomy by ultrasound were first studied to ensure absence of stones or biliary sludge. The women were then assigned to a hypocaloric regimen [5.02 MJ (1200 kcal)/d] and to receive 1200 mg/d of ursodeoxycholic acid (UDCA), 11.3 g/d of (n-3) PUFA or a placebo for 6 wk. BMI, CSI and NT were recorded at baseline and at the end of the experimental period. BMI decreased 5.75 +/- 2.7%/mo (range, 1.5-12.42%/mo) during the experiment. The CSI did not change in any of the groups. Cholesterol NT decreased significantly in the UDCA and placebo groups, but not in the (n-3) PUFA group. None of the women had developed gallstones at 6 wk. These results suggest that (n-3) PUFA maintain the CSI and NT in obese women during rapid weight loss, which probably results in the prevention of cholesterol gallstone formation.

Adult↗
PubMed2001

Lack of association between Helicobacter sp colonization and gallstone disease.

Recently, Helicobacter sp has been identified in resected gallbladder tissue and in collected bile from Chilean patients with chronic cholecystitis. Therefore, it an association between bile Helicobacter sp and gallbladder cancer has been proposed. Interestingly, both Helicobacter colonization and gallstone disease (GD) happen very frequently in Chile. However, whether there is an association between Helicobacter colonization and GD has not been completely studied. The aim of this study was to determine the incidence of Helicobacter in human gallbladder tissues with GD. The study included 95 Mexican patients undergoing cholecystectomy. Collected gallbladder specimens were assessed to identify Helicobacter sp using histology, immunohistochemistry, and polymerase chain reaction (PCR) analysis using Helicobacter-specific 16-S ribosomal RNA primers. Of the 95 specimens examined in detail, all had stones as follows: 56 (59%) had chronic cholecystitis; 7 (7.4%), acute cholecystitis: 15 (16%), both chronic and acute cholecystitis, 10 (9.5%), cholesterolosis, and 7 (7.4%), lymphoid hyperplasia. Specimens were considered positive for Helicobacter when histology was positive. Only 1 of the 95 specimens was positive for Helicobacter by immunohistochemistry analysis; 1 of 32 cases, by PCR. These results suggest a low incidence of Helicobacter in the gallbladder epithelium of Mexican patients with GD. However, we can not discard the existence of uncommon Helicobacter sp in gallbladder epithelium and its association with gallstone pathogenesis. Additionally, this study suggests no apparent association between GD and Helicobacter colonization in a Mexican population.

Adult↗
PubMed2000

[BICAP tumor probe in the palliative treatment of malignant esophageal stenosis].

BACKGROUND: BICAP tumor probe is a device that consists in an energy source and olives that deliver bipolar electricity. It can be used for the fulguration of esophageal tumors after endoscopic dilatation. AIM: To report the experience in the treatment of malignant esophageal stenoses using the BICAP tumor probe. PATIENTS AND METHODS: Patients with advanced esophageal tumors in aphagia, that were not candidates for palliative surgery were included in this study. After endoscopic dilatation, the tumor was fulgurated with the BICAP tumor probe. RESULTS: Twenty one patients (nine male, aged 43 to 91 years old) were treated with the device. A mean of 1.3 sessions with BICAP were necessary to obtain tumor permeabilization, which was obtained in all patients. One patient died of pneumonia 15 days after the procedure. All other patients were ingesting liquid or semisolid diets after two months of follow up. Mean survival after the procedure was 3.8 months. CONCLUSIONS: Electrical fulguration of esophageal tumors is a valid therapeutic alternative in aphagic patients.

Adult↗
PubMed2000

[A new instrument for the evaluation of the medical profession. Use of the OSCE method].

BACKGROUND: Objective structured clinical examination has advantages over traditional oral examination of medical student. However, it is not routinely used in Chile. AIM: To describe the objective structured clinical examination system and report the results of its first use with Chilean medical students. MATERIAL AND METHODS: Thirteen interns ware evaluated at the end of their surgical rotation, using the objective structured clinical examination. Thirteen stations were structured for this examination: one for history taking, two for physical examination, four for problem solving and knowledge, one for radiological interpretation, one for instrumental recognition, one for skills and one for text comprehension. There were a total of 88 questions. RESULTS: All students exceeded 60% of requirements. Mean approval score was 73%. The higher score was 80% and the lower 61%. Ten students had a score over 70%. The method was well accepted by teachers and students. CONCLUSIONS: This first local experience with the objective structured clinical examination was successful.

Chile↗
PubMed1999

The adipose tissue to serum dichlorodiphenyldichloroethane (DDE) ratio: some methodological considerations.

Dichlorodiphenyldichloroethane (DDE) adipose tissue level has been regarded as a preferred indicator of accumulated human exposure to DDT; however, blood sera are more feasible to obtain and analyze than adipose tissue samples. Inconsistent and scarce information exists in relation to the adipose tissue/serum DDE ratio. As a part of a hospital-based case-control study performed in Mexico City from 1994 to 1996, 198 paired serum and adipose tissue samples were obtained from 72 women with histologically confirmed breast cancer and 126 women with benign breast disease. Both adipose tissue and serum DDE levels were determined by gas-liquid chromatography and reported as ppb lipid weight (ng/g) as well as wet basis (ng/ml). Results showed that the adipose tissue/serum DDE ratio (ADSE) varies according to the type of information (lipid vs wet basis, arithmetic vs geometric means) used for its estimation. ADSE gets a value near 1 (1.1) only when the geometric DDE levels in lipid basis are used for its estimation. The correlation between DDE serum and adipose tissue levels was found (r=0.364, P<0.001). The ADSE did not vary by disease status, nor was it altered by parity, history of breast-feeding, and other reproductive characteristics. We endorse the use of venipuncture instead of biopsy as a way to estimate DDT body burden levels in further research.

Adipose Tissue↗
PubMed1998

The effect of uncertainty on the demand for medical care, health capital and wealth.

We analyze the effect of the uncertainty of the incidence of illness on the demand for medical care and on the accumulation of health capital and wealth over the retirement years. We use a simplified version of a dynamic Grossman household production model to characterize patterns of an individual's precautionary behavior. Elderly individuals respond to uncertainty by smoothing their expected utility over time by making specific patterns of purchases of medical care and consumption. We examine these patterns for individuals with different degrees of risk aversion.

Aged↗