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Biomedical subjects

Manuel Alvarez

Publications and source records attributed to Manuel Alvarez.

18 recordsLinked to original sources
PubMed2006

Follicular dendritic cell sarcoma in pregnancy: case report and review of the literature.

Follicular dendritic cell (FDC) sarcoma is a rare tumor. Most cases that have been described involve lymph nodes in young adults, but have not been reported in pregnancy. We describe the case of a 20-year-old woman with a FDC sarcoma diagnosed during pregnancy that initially presented as a painful mass in the right axilla. The patient underwent a tumor excision and chemotherapy. The intrapartum course was uncomplicated and she delivered a live female child at 34 weeks. During her postpartum course, she received radiation therapy and chemotherapy.

Adult↗
PubMed2006

Acute myelogenous leukemia mimicking a hemolysis, elevated liver enzymes, and low platelets syndrome during pregnancy: case report and review of the literature.

Acute leukemia is a rare malignancy of pregnancy. When it develops, there are many complications to consider and management becomes exceedingly difficult. We report a case of acute myelogenous leukemia presenting as preeclampsia and fetal demise at 36 weeks of gestation. A 30-year-old multigravida presented with intrauterine fetal demise at 36 weeks' gestation, hypertension, and thrombocytopenia. The patient received platelet and packed red blood cell transfusion, with concurrent prophylactic magnesium sulfate and dexamethasone treatment. Following labor induction, the patient delivered a nonviable female fetus and suffered a stroke postpartum. Peripheral smear and flow cytometry revealed the patient had acute myeloid leukemia with prominent monocytic differentiation. The patient expired on postpartum day six. Acute leukemia during the pregnancy is associated with an unfavorable outcome.

Adult↗
PubMed2006

Gallbladder disease is associated with insulin resistance in a high risk Hispanic population.

BACKGROUND/AIMS: We tested whether cholesterol gallstone disease (GS) is associated to insulin resistance and serum C-reactive protein (CRP) in a high risk population. METHODS: This was a nested case-control study on 881 Chilean subjects that included clinical examination, abdominal ultrasound and blood chemistries. Insulin resistance was determined by the homeostasis model assessment index (IR-HOMA). RESULTS: Compared to controls (n = 582), age and sex adjusted median IR-(HOMA) was significantly elevated in subjects with GS (n = 299) (P < 0.001). Risks of GS in subjects with insulin resistance and different body mass index (BMI) were: BMI < 25, 2.2 (1.1-4.7); BMI 25-30, 1.5 (0.9-2.5) and BMI > 30, 1.7 (1.0-2.9). Risk of GS in subjects with metabolic syndrome was 1.7 (CI, 1.2-2.5) and with fatty liver, 1.5 (1.1-2.2). Risk of GS in subjects with CRP > 1 mg/dL was 1.0 (0.7-1.7). CONCLUSIONS: GS is associated to insulin resistance, fatty liver and to metabolic syndrome, but not to serum CRP in a high risk Hispanic population. Insulin resistance could have a major role in the pathogenesis of GS favoring the production of cholesterol supersaturated bile and altering gallbladder function.

Adult↗
PubMed2006

[Advances in radiography of the small intestine: computed tomography enteroclysis].

Computed tomography (CT) enteroclysis is a new technique consisting of helical CT of the abdomen and pelvis after administration of water through a nasojejunal tube and intravenous contrast, resulting in adequate distension and visualization of the small bowel wall. The use of this technique is especially recommended in patients with gastrointestinal bleeding of unknown etiology, possible neoplastic processes of the small bowel, partial small bowel obstruction, and inflammatory bowel disease. One-hundred consecutive patients underwent CT enteroclysis (multiple detectors; 8, 16, or 64) over a 1-year period for suspected lesions of the small bowel. Of these, 31 were positive: Crohn's disease (17), tumors (8), partial obstruction (2), radiation enteritis (1), sprue (1), pneumatosis cystoids (1), and dilatation of bowel loops (1). In 28 of the 31 patients, the findings were confirmed by pathology, endoscopy or clinical follow-up.

Adolescent↗
PubMed2005

Incidence of BRCA1 and BRCA2 mutations in 54 Chilean families with breast/ovarian cancer, genotype-phenotype correlations.

Our aim was to analyze the incidence of mutations in BRCA1 and BRCA2 genes in 54 families with breast/ovarian cancer. Families were selected from three Institutions following the standard criteria for hereditary breast/ovarian cancer. PCR amplification of all exons was performed, followed by SSCP, heteroduplex, PTT and sequencing analysis. We identified eight truncation mutations, three in the BRCA1 gene and five in the BRCA2 gene. Three of these mutations have not been reported previously by other groups: 308insA in one family, 3936 C>T in two families, for BRCA1, and 4970insTG in one family for BRCA2. In addition two families having Ashkenazi Jewish ancestors present the well known mutations 185delAG and 6174delT. Interestingly, 5 out of 11 families have mutations recurrent in Spanish families. Among the 54 families selected, seven have breast and ovary cancer cases, and only two presented a mutation in BRCA1 or BRCA2 genes. Other cancers as prostate and stomach are frequent among relatives carrying the mutation. Five cases of very early onset (<31 years old) breast cancer were detected. The frequencies of BRCA1 (0.074) and BRCA2 (0.13) mutations in our families is low but similar to the incidence found in other populations, like in Spain. Since is widely known that risk factors that modulate the development of breast cancer such as lifestyle risk factors, geographic location, country of origin and socioeconomic status, besides a familial history of breast cancer our findings suggest that the history of colonization and immigrations is very relevant when studying hereditary factors associated to breast cancer.

Adult↗
PubMed2005

Increased orocecal transit time in patients with nonalcoholic fatty liver disease.

Intestinal bacterial overgrowth (IBO) has been suggested to play a pathogenic role in patients with nonalcoholic fatty liver disease (NAFLD). Delayed intestinal transit may contribute to IBO development. Ten nondiabetic patients with NAFLD and abnormal liver enzymes were recruited. Ten healthy individuals, matched by sex, age, and body mass index, were used as controls. Orocecal transit time (OCTT) was measured by the lactulose breath test. Anti-endotoxin core antibodies (EndoCAb) were determined. The effect of oral norfloxacin (400 mg BID during 2 weeks) on liver enzymes, lactulose breath test, and EndoCAb was also studied. NAFLD patients had higher basal breathed H2 and prolonged OCTT compared to controls (127 +/- 61 vs. 57 +/- 23 min, respectively; P = 0.0037). EndoCAb titers were similar in NAFLD patients and controls. Norfloxacin administration had no effect on ALT levels, lactulose breath test, or EndoCAb titers in patients with NAFLD. The present data show evidence of deranged intestinal motility in nondiabetic patients with NAFLD and support the hypothesis that NAFLD could be linked to endotoxin-induced liver damage of intestinal origin.

Adult↗
PubMed2005

Down-regulation of endothelial adhesion molecules and leukocyte adhesion by treatment with superoxide dismutase is beneficial in chronic immune experimental colitis.

Modulation of adhesion molecule expression that govern trafficking of leukocytes into the inflamed intestine is envisioned as a new strategy for treatment of inflammatory bowel disease (IBD). This study was designed to determine the impact of reducing oxidative stress on adhesion molecules expression and leukocyte recruitment in experimental chronic colitis. For that purpose, colitic interleukin-10 knockout and wild-type mice were studied. Groups of animals were treated with Cu/Zn superoxide dismutase (SOD1) 13 mg/kg/d or vehicle for either 7 or 14 days. Expression of vascular cell adhesion molecule-1 and mucosal addressin cell adhesion molecule-1 were determined; leukocyte-endothelial cell interactions in colonic venules were studied with intravital microscopy; and changes in colon pathology and biomarkers of colitis severity were determined. Development of colitis was associated with a marked increase in endothelial vascular cell adhesion molecule-1 and mucosal addressin cell adhesion molecule-1 expression, which were significantly reduced by treatment with SOD1. The increase in leukocyte rolling and adhesion in colonic venules of colitic mice were significantly reduced by administration of SOD1. This treatment markedly reduced colonic lipid hydroperoxidation, myeoloperoxidase activity, and plasma levels of serum amyloid A protein and resulted in significant, although modest, reductions in histologic damage score. The therapeutic value of SOD1 when administered prophylactically was assessed in the dextran sulfate sodium model of colitis with similar positive results. These results indicate that SOD1 affords significant amelioration of colonic inflammatory changes in experimental colitis. Down-regulation of adhesion molecule expression, reduction of lipid hydroperoxidation, and recruitment of leukocytes into the inflamed intestine contribute to this beneficial effect.

Animals↗
PubMed2004

Examining within-country variation of maternity costs in the context of a multicountry, multicentre randomised controlled trial.

Understanding why healthcare costs vary between patients and between health facilities is important in guiding health policy decisions as well as in research. However, there is no comprehensive framework that analysts commonly use for expressing and examining causes of cost variation in the field of healthcare. The aim of this study is to better understand the size and causes of within-country healthcare cost variation, through presenting evidence for size and sources of such variations for two countries (Cuba and Thailand) in the context of a randomised controlled trial on antenatal care. The article separates total costs into their two components: unit costs and health service use. Unit costs are further separated into input quantity per patient visit or day, and the prices of these resources. The results show that the main determinant of average cost is the staffing pattern and productivity, whereas the main determinants of health service use include the model of antenatal care being practised and the risk status and illnesses suffered by patients. However, variations in inpatient health service use between facilities are largely related to unexplainable variations in practice between facilities, irrespective of the trial arm. In conclusion, cost variations have important implications for the design of clinical trials and for policy makers using evidence from trials in planning health services and budgets.

Ambulatory Care↗
PubMed2004

[Determination of a BRCA1 gene mutation in a family with hereditary breast cancer].

BACKGROUND: Breast cancer is the main cause of death among women between 40 and 55 years old, in whom the hereditary cases are common. Therefore, the molecular diagnosis of germ line mutations involved in breast cancer susceptibility is relevant. BRCA1 and BRCA2 have been described as the two major genes involved in familial breast/ovarian cancer. We are performing a screening of BRCA1 and BRCA2 genes, in a group of 50 high risk Chilean families for breast/ovarian cancer. We have detected a mutation, 3936 C>T, that leads to a truncated protein, in two affected women from one of the families in study. AIM: To report the results of the screening for 3936 C>T in healthy relatives of index women. MATERIAL AND METHODS: The molecular diagnosis of this mutation was offered to the healthy members of this family, and 17 relatives accepted to be tested. The region of the BRCA1 gene that includes the 3936 C>T mutation, was analyzed through PCR amplification, digestion with restriction enzyme BstNI, and direct sequencing. RESULTS: 3936 C>T DNA mutation was present in 8 relatives. CONCLUSIONS: Considering the high risk of having a mutation in the BRCA1 gene, specially in pre-menopausal women, the molecular diagnosis, genetic and clinical counseling are highly relevant. In Chile the molecular diagnosis is still not widely applied.

Breast Neoplasms↗
PubMed2003

Maximum FIO2 in minimum time depending on the kind of resuscitation bag and oxygen flow.

OBJECTIVE: To analyze what FIO2 can be reached, and how long it takes using the different autoinflated resuscitation bags and increasing oxygen flows. DESIGN: Experimental analysis on the effect of three different models of autoinflated resuscitation bag and increasing oxygen flows in the final FIO2, and time spent to reach it. SETTING: Laboratory, with a gas analyzer and a lung simulator to measure inspired FIO2. INTERVENTIONS: Simulated cardiopulmonary resuscitation. Three different autoinflated resuscitation bags were studied; A, the classic one with oxygen delivery directly into the bag, without reservoir, B, a new one without the reservoir device; and C, a new one with the reservoir device properly implemented. Increasing oxygen flows were administered until FIO2 stabilized. RESULTS: With model A the maximum FIO2 reached was 0.73 in 70 s using a 20 l/min oxygen flow. With model B the maximum FIO2 reached was 0.65 in 90 s using a 20 l/min oxygen flow. The best FIO2 (0.99) was reached using model C in 55 s with 12 l/min oxygen flow. In the three models a high correlation between oxygen flow and FIO2 was found (r>0.8). CONCLUSIONS: It is mandatory to use model C resuscitation autoinflated bag with 12 l/min of oxygen flow during the resuscitation maneuvers. Using another autoinflated bag model, maximum oxygen flows (i.e., 20 l/min) are needed. The resuscitation autoinflated bags showed less effectiveness when they were not properly assembled.

Analysis of Variance↗
PubMed2003

Role of transvaginal sonographic cervical length in predicting spontaneous preterm delivery in triplet pregnancies with therapeutic cerclage.

OBJECTIVE: To assess the role of transvaginal sonographic cervical length in predicting spontaneous preterm delivery at < 32 weeks in patients with both triplet pregnancy and therapeutic cerclage. STUDY DESIGN: The maternal records of all triplet pregnancies with therapeutic cerclage and sonographic cervical length before and after cerclage were reviewed (n = 17). Each of these triplet gestations was matched with 2 triplet pregnancies without cerclage based on cervical length after cerclage (+/- 0.5 cm) and gestational age (+/- 3 weeks). Statistical analysis included Fisher's exact test or chi 2 analysis, one-way analysis of variance, logistic regression analysis and receiver operating characteristic curve analysis. RESULTS: Cerclage was placed at a gestational age of 19.0 +/- 3.1 weeks (mean +/- SD) and increased cervical length from 2.0 +/- 0.7 cm to 3.1 +/- 1.4 cm (P < .05). The rate of spontaneous preterm delivery at < 32 weeks was higher among cases than controls (7/17 vs. 4/27, P = .08). Logistic regression analysis demonstrated that only postcerclage cervical length was predictive of spontaneous preterm delivery at < 32 weeks, with a cervical length of 3.3 cm the optimal predictor. CONCLUSION: In women with triplets and therapeutic cerclage, the only significant predictor of spontaneous preterm delivery at < 32 weeks is cervical length after cerclage placement.

Adult↗
PubMed2002

Estimated risk of transfusion-transmitted viral infections in Spain.

BACKGROUND: Estimates of the risk of transfusion-transmitted viral infections are essential for monitoring the safety of the blood supply. The aim of the present study was to estimate the residual risk of blood-borne viral infections in Spain. STUDY DESIGN AND METHODS: Incidence rates of seroconversion for HIV, HBV, and HCV were calculated among 673,018 persons who donated blood more than once (repeat donors), from 1997 through 1999 at 22 blood donation centers (for a total of 2,464,964 allogeneic blood donations and 1,052,752 person-years). RESULTS: Incidence rates per 100,000 person-years and their 95-percent CIs were as follows: for HBV, 8.36 (5.24-12.62); for HIV, 3.23 (2.24-4.52); and for HCV, 3.70 (2.63-5.07). After adjusting incidence rates for the estimated duration of the infectious window period for each virus, the residual risk per unit transfused was estimated at 1 in 513,000 for HIV, 1 in 74,000 for HBV, and 1 in 149,000 for HCV. The introduction of new screening test based on NAT would have reduced these risks by 27 to 50 percent for HIV, by 42 percent for HBV, and by 62 to 65 percent for HCV. CONCLUSION: The residual risks of transmission of HIV, HBV, and HCV in Spain are similar to those reported in other countries and should be further reduced in the future.

Biomarkers↗
PubMed2002

[Natural history of cholelithiasis and incidence of cholecystectomy in an urban and a Mapuche rural area].

BACKGROUND: Cholelithiasis is the second cause of hospital admissions in Chile. AIM: To study the prevalence of symptomatic gallstone disease and opportunity of cholecystectomy in La Florida, Santiago and among Mapuche Indians in Huapi Island. PATIENTS AND METHODS: In the period 2000-2001, we contacted to 71% (1127 subjects) and to 61% (145 subjects) patients of La Florida and Huapi Island, respectively, that had previously participated in an epidemiological study on cholelithiasis in 1993. We defined symptomatic gallstone patients as those with a history of biliary colic. Each patient was subjected to gallbladder ultrasound. RESULTS: In 1993, 30-35% of gallstone patients were symptomatic (approximately 70% women). During the lapse 1993-2001, only 50% of subjects from La Florida and 25% of patients from Huapi Island were cholecystectomized (p < 0.05). Fifty percent of cholecystectomies were emergency operations. In 38 symptomatic Mapuche Indians from Huapi, cholecystectomy was indicated in 2001. After five months of the indication, only one of these subjects had been operated. Laparoscopic cholecystectomy represented 40% of all cholecystectomies performed in the National Health Service Hospitals. CONCLUSIONS: This study demonstrates an unacceptable high prevalence of symptomatic gallstone patients remaining non-operated in both the urban and rural communities. This reciprocally correlates with the high frequency of emergency cholecystectomies and the high incidence of gallbladder cancer among Chileans. This study contrasts negatively with the situation of Scotland, where 73.5% of cholecystectomies were laparoscopic in 1998-1999. To reach Scotland standards, the Chilean Public Health System should increase the number of cholecystectomies from 27,000 in 2001 to 57,510

Adult↗
PubMedDate not supplied

Inhibition of sulfide generation in a reclaimed wastewater pipe by nitrate dosage and denitrification kinetics.

Sulfide generation should be avoided during wastewater transportation. The efficiency of nitrate dosing for the inhibition of sulfide generation was evaluated during reclaimed wastewater transport with two nitrate doses, 2.5 and 5 mg/L nitrate-nitrogen (NO3-N). A calcium nitrate [Ca(NO3)2] solution was injected at the beginning of the 61-km-long gravity pipe, which is part of the Reclaimed Wastewater Reuse System of South Tenerife (Spain). During transportation, after dissolved oxygen depletion, a denitrification process took place. With the 5 mg/L NO3-N dose, nitrate was not completely removed at the end of the pipe, whereas with 2.5 mg/L NO3-N, a complete denitrification was achieved. Sulfide generation was completely inhibited with the 5 mg/L dose. However, with 2.5 mg/L, sulfide generation was not completely inhibited but delayed and minimized to a great extent. Denitrification was stoichiometrically limited by the availability in biodegradable matter. An empirical equation enables one to predict the nitrate concentration.

Agriculture↗
PubMedDate not supplied

Clinical and epidemiological features of 147 Chilean patients with chronic hepatitis C.

Prevalence, modes of transmission, clinical characteristics and outcomes of hepatitis C (HCV) infection vary in different geographical areas. We aim to describe clinical and epidemiological features of Chilean patients infected with hepatitis C virus. An analysis of demographic, epidemiological, clinical and laboratory data of patients referred to a liver clinic and blood donors with chronic hepatitis C was carried out. 147 patients were evaluated, 68 (46%) were male. Median age was 56 years, median infection age was 27 years and median duration of infection was 27 years. 52.5% of the patients were cirrhotic, and estimated risk of progression to cirrhosis was 16% at 20 years from infection. Risk factors for acquisition of the disease among patients were: Blood transfusion 54%, injection drug use 5%, and risky sexual behavior 2%. No factor was identified in 43% of the patients. Twelve of 64 (18.8%) family members tested positive for HCV antibodies. Genotype 1b was predominant (82%), and 52% of patients had high viral load (>850.000 IU/mL). Liver biopsy was available in 50 patients, showing advanced fibrosis in 54%. These patients were in average 10 years older and tended to have longer duration of infection. Hepatocellular carcinoma was present at the moment of enrollment in 7 patients and developed in 4 more patients during follow up (2.4 years). In conclusion, the natural history and clinical characteristics of HCV infection in Chilean patients is similar to that described elsewhere. The main risk factor was blood transfusion. A significant proportion of patients had advanced liver disease or hepatocellular carcinoma at time of diagnosis.

Adult↗
PubMedDate not supplied

Incidence and prevalence of hepatitis C virus infection in Chile.

UNLABELLED: Chronic hepatitis C is a major cause of liver-related morbidity and mortality. Epidemiological data regarding this infection in developing countries is scanty. METHODS: Prevalence of hepatitis C (HCV) infection was investigated in a random sample of Chilean general adult population older than 20 years of age. Additionally, frequency of HCV infection was assessed in group of native Chilean Amerindians (Mapuche Indians) living in an isolated locality of the Southern Chile. Incidence of HCV infection was estimated using serum samples separated by 7 years (1993-2000). RESULTS: Among 959 subjects, prevalence of anti-HCV antibodies was 1.15% (95% CI 0.48-1.82%) and 0.83% when only RIBA-confirmed cases were considered. Among these subjects, 62.5% had detectable HCV RNA in serum and 40% of them had a history of blood transfusion. Age distribution of cases showed a steadily increasing prevalence with age. Estimated incidence of new HCV infections was 15 per 100,000 subjects per year in the period 1993-2000. No cases were detected among the 145 Mapuche subjects studied. CONCLUSIONS: HCV infection is a prevalent disease in the Hispanic population of Chile with a low incidence in the last decade, whereas it was not detected in an isolated Mapuche Indian community. Age distribution of prevalence suggests that the peak of infection in Chile occurred 30 to 50 years ago.

Adult↗