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M Vela

Publications and source records attributed to M Vela.

18 recordsLinked to original sources
PubMed2006

Acid and non-acid reflux in patients with persistent symptoms despite acid suppressive therapy: a multicentre study using combined ambulatory impedance-pH monitoring.

BACKGROUND AND AIMS: Empiric proton pump inhibitor (PPI) trials have become increasingly popular leading to gastroenterologists frequently evaluating gastro-oesophageal reflux disease (GORD) patients only after they have "failed" PPI therapy. Combined multichannel intraluminal impedance and pH (MII-pH) monitoring has the ability to detect gastro-oesophageal reflux (GOR) episodes independent of their pH and evaluate the relationship between symptoms and all types of GOR. Using this technique, we aimed to characterise the frequency of acid and non-acid reflux (NAR) and their relationship to typical and atypical GOR symptoms in patients on PPI therapy. METHODS: Patients with persistent GORD symptoms referred to three centres underwent 24 hour combined MII-pH monitoring while taking PPIs at least twice daily. Reflux episodes were detected by impedance channels located 3, 5, 7, 9, 15, and 17 cm above the lower oesophageal sphincter (LOS) and classified into acid or non-acid based on pH data from 5 cm above the LOS. A positive symptom index (SI) was declared if at least half of each specific symptom events were preceded by reflux episodes within five minutes. RESULTS: A total of 168 patients (103 (61%) females and 65 (39%) males; mean age 53 (range 18-85) years) underwent combined MII-pH monitoring while taking PPIs at least twice daily. One hundred and forty four (86%) patients recorded symptoms during the study day and 24 (15%) patients had no symptoms during testing. Sixty nine (48%) symptomatic patients had a positive SI for at least one symptom (16 (11%) with acid reflux and 53 (37%) with NAR) and 75 (52%) had a negative SI. A total of 171 (57%) typical GORD symptoms were recorded, 19 (11%) had a positive SI for acid reflux, 52 (31%) for NAR, and 100 (58%) had a negative SI. One hundred and thirty one (43%) atypical symptoms were recorded, four (3%) had a positive SI for acid reflux, 25 (19%) had a positive SI for NAR, and 102 (78%) had a negative SI. CONCLUSION: Combined MII-pH identifies the relation of reflux of all types to persistent symptoms and the importance of NAR in patients taking PPIs.

Adolescent↗
PubMed2001

Combined multichannel intraluminal impedance and pH-metry: an evolving technique to measure type and proximal extent of gastroesophageal reflux.

The accepted "gold standard" for measuring gastroesophageal reflux (GER), distal esophageal pH recording, has limited ability to measure nonacid GER, a potentially important cause of symptoms, in an era of potent acid-suppressing medications. A combination of multichannel intraluminal impedance (MII) and pH- metry offers an advantage over pH measurement alone. MII can detect GER at multiple levels of the esophagus independent of pH. In addition, use of MII enables refined characterization of intraluminal events, including presence, type (air, liquid, or mixed), and spaciotemporal characterization of a bolus. MII has the potential to become a useful clinical tool to assess ongoing reflux in patients on acid-suppression therapy.

Electric Impedance↗
PubMed2000

Application of focused-microwave wet digestion to the determination of trace metals in human gallstones by ICP/AES.

We propose an analytical digestion method for trace metal determination (Co, Cr, Cu, Fe, Mn, Ni and Zn) in gallstones, in an attempt to facilitate detection of their origin. The method consists of sample digestion with HNO3 and H2O2 by means of focused microwave. Metals are quantified by inductively coupled plasma atomic emission spectroscopy. The effect of calcium concentration in the analytical solutions was studied. Cu, Fe, Mn and Zn were detected in all the samples analysed and the highest concentrations were obtained for Cu and Fe, especially in black-pigmented gallstones. The reproducibility in terms of %RSD, determined in the gallstones with the lowest metal content, was below 5% for Cu, between 10% and 15% for Mn and Zn and up to 25% for Fe.

Calcium↗
PubMed1999

DNA probe analysis for the carriage of enterotoxigenic Clostridium perfringens in feces of a Mexican subpopulation.

Clostridium perfringens has been implicated as a causative agent of foodborne poisoning, infectious diarrhea (not associated with foods), gas gangrene, and several veterinary diseases. Fecal carriage of enterotoxigenic strains of this bacterium appears to be important in the development of infectious diarrhea and as a source of C. perfringens contamination of foods. In this work, carriage of this bacterium in feces of a Mexican population was analyzed. C. perfringens was found in 126 of the 200 fecal samples obtained from healthy individuals from northern Mexico. The samples had an average of 7.4 x 10(3) spores per gram, with the elderly population showing the highest levels. Dot blot analyses using a dig-labeled probe specific for the enterotoxin gene showed that 7% of the samples had isolates with toxigenic potential.

Adolescent↗
PubMed1999

Neonatal screening for congenital hypothyroidism in Mexico: experience, obstacles, and strategies.

OBJECTIVE: To report the experience, obstacles, and strategies of screening for congenital hypothyroidism. SETTING: Newborns in Mexico. METHODS: Thyroid stimulating hormone (TSH) was measured by enzyme immunoassay using commercial kits in 1,140,364 newborns. RESULTS: There were 464 positive cases, of whom 299 (64.4%) were girls. 236 (50.9% showed ectopic nodules, 202 (43.5%) thyroid agenesis, 21 (4.5%) dyshormonogenesis, and 5 (1.1%) an unclassified goitre. The false positive rate was 0.024% and there were 11 false negative results. Currently, 600,000 (26%) of the 2,300,000 newborns are screened. This percentage has been increased in recent years by taking samples from cord blood and will be increased further by starting congenital hypothyroidism screening at social security units and by midwives screening infants born at home. CONCLUSIONS: Mental retardation in infants in developing countries can be reduced by neonatal screening, and carefully planned strategies can steadily extend the benefits of screening.

Blood Specimen Collection↗
PubMed1998

Cardiovascular risk factors associated with clinically isolated and diffuse atherosclerosis in Spanish patients with coronary artery disease.

BACKGROUND: Patients with coronary artery disease (CAD) associated with peripheral (PAD) or cerebrovascular disease (CVD), a condition called diffuse atherosclerosis, have a higher risk of death than patients with isolated CAD. The prevalence of diffuse atherosclerosis and the atherogenic risk factors associated with this condition in our geographic area have not been described previously. METHODS: A cohort of 2597 patients (62 +/- 10.8 years, 665 women) consecutively admitted at Bellvitge Hospital because of acute coronary syndromes were studied. CAD patients were divided in two groups with diffuse and located atherosclerosis according to whether they had or they had not an associated PAD or CVD. Baseline history, physical data and lipid profile were recorded in each patient according to a standardized questionnaire. RESULTS: A total of 370 patients (14.2%) had diffuse atherosclerosis. Among them, there were more men and women older than 55 years than among those with isolated CAD. Patients with diffuse atherosclerosis were more frequently hypertensive, diabetic and former smokers than those with isolated CAD (60.5% vs. 49.4%, P < 0.01; 37.4% vs. 24.5%, P < 0.01; and 47% vs. 35.7%, P < 0.01, respectively). There were no significant differences in the mean values of total cholesterol (TC), low-density cholesterol (LDL-C), high-density cholesterol (HDL-C) and triglycerides between both groups of patients, but patients with diffuse atherosclerosis had a lower HDL-C/TC ratio, with borderline statistical significance (0.18 +/- 0.06 vs. 0.19 +/- 0.06, P = 0.06). Using multiple logistic regression analysis, the variables associated with diffuse atherosclerosis in men were age greater than 55 years (OR 1.97, CI 1.33-2.93), hypertension (OR 1.50, CI 1.14-2.20), diabetes (OR 1.78, CI 1.20-2.70), smoking (former smokers) (OR 2.09, CI 1.36-3.24) and HDL-C/TC < 0.20 (OR 1.60, CI 1.18-2.17); and in women hypertension (OR 3.43, CI 1.48-7.94) and diabetes (OR 2.58, CI 1.55-4.80). CONCLUSIONS: Clinically overt diffuse atherosclerosis is a relatively common disease. Older patients and those with hypertension, diabetes or low HDL-C/TC ratio are more likely to have diffuse atherosclerosis than those without these conditions.

Aged↗
PubMed1996

Apparent higher frequency of phenylketonuria in the Mexican state of Jalisco.

The geographic origin of Mexican patients with phenylketonuria (PKU) in Mexico City and in southern California was studied. Compared to patients with other metabolic disorders, patients with PKU were significantly more likely to have originated from the Los Altos region of the state of Jalisco and its environs. The incidence of PKU among mentally retarded students attending special education schools was found to be significantly higher in Jalisco (particularly the Los Altos region) than in the neighboring state of Guanajuato (1.09% vs 0.3%). These results strongly suggest a "population of origin" effect, the mutant allele(s) having been introduced by the Spanish ancestors of the current population. Our findings also support the addition of PKU to the neonatal screening program for this region of Mexico.

Child↗
PubMed1996

Apolipoprotein E polymorphism and gallstones.

BACKGROUND & AIMS: Apolipoprotein (apo) E is a genetically polymorphic protein influencing lipoprotein metabolism and the risk of both atherosclerosis and Alzheimer's disease. As opposed to common apo E3, apo E2 decreases and apo E4 increases hepatic lipoprotein uptake; hence, apo E4 could promote gallstone formation by increasing hepatic and biliary cholesterol concentrations. This study was designed to evaluate whether apo E polymorphism is related to gallstone risk. METHODS: apo E phenotype was determined in subjects older than 40 years of age (160 with and 125 without gallstones) and in 61 patients with cholesterol gallstones who underwent cholecystectomy. Bile composition, nucleation time, and gallstone features were analyzed in surgical patients. RESULTS: The E4/3 phenotype was enriched in both patients with gallstones and those who underwent cholecystectomy, with significantly (P < 0.006) higher epsilon 4 allele frequencies than in gallstone-free subjects (odds ratio, 2.67 [95% confidence limits, 1.23-5.93] and 3.62 [95% confidence limits, 1.49-8.91], respectively); women, but not men, accounted for these differences. The prevalence of the epsilon 4 allele increased with age in patients with gallstones, whereas the opposite occurred in gallstone-free subjects. Biliary lipid and gallstone cholesterol content tended to increase in the sequence E4 > E3 > E2 in patients who underwent cholecystectomy. CONCLUSIONS: Carrying the apo E4 isoform is a genetic risk factor for cholelithiasis in humans, thus adding another adverse effect of apo E polymorphism on health.

Adult↗
PubMed1995

Molecular analysis of the phenylalanine hydroxylase gene in Mexican phenylketonuric patients.

The molecular analysis of the human phenylalanine hydroxylase (PAH) gene in Mexican phenylketonuric (PKU) patients is described. We analyzed the restriction fragment length polymorphism (RFLP) haplotypes of five probands and ten non-affected relatives, belonging to four unrelated PKU families. Twenty-nine alleles were typified, corresponding to 12 different haplotypes. Eight RFLP haplotypes corresponded to those described in other populations, while the remaining were unreported haplotypes, appearing both on normal and PKU chromosomes. Using the polymerase chain reaction (PCR) and the allele-specific oligonucleotide assay (ASO), we also screened for the IVS10 mutation, one of the most common PAH gene mutations in Mediterranean countries. Forty-two percent of the PKU chromosomes analyzed bore the IVS10 mutation, although it was present in the heterozygous state in all cases. Our data show an important genetic heterogeneity at the PAH locus in the Mexican population, and report the genetic influence of the Spanish immigration to the American continent.

Female↗
PubMed1989

Anti-goat immunoglobulin antibodies in diabetic children at diagnosis and follow-up: comparison with islet cell antibodies and other autoantibodies.

The presence of antibodies reacting with human as well as animal immunoglobulins in sera from recent onset Type I diabetic patients has been recently demonstrated by some of our group. In the present study, the occurrence of these antibodies has been evaluated in sera from 19 Type I diabetic patients, at diagnosis and at follow-up within three years, and from 26 normal subjects, and has also been compared with the presence of islet cell antibodies and other organ-specific autoantibodies. A solid-phase radioimmunoassay has been used: serum was incubated in goat immunoglobulin-coated wells and the binding of 125-I-anti-human immunoglobulin antibodies was evaluated. Anti-goat immunoglobulin antibodies were above the 90th percentile of normal values in all diabetic patients at diagnosis (median, interquartile range, in micrograms 125I-antibody bound/1 serum: 83, 77.5-88, versus 51.5, 44.5-62 in normal subjects, P less than 0.001) and significantly declined with time after diagnosis (P less than 0.001). Islet cell antibodies were present in 79% of patients at diagnosis, whereas at least one other auto-antibody was found in 21% of patients. In the follow-up study the decline in anti-goat immunoglobulin antibody levels was different from that of islet cell antibody positivity. A circulating immunoglobulin reacting with other immunoglobulins is thus present in the early stages of Type I diabetes and may well play a part in the complex immunopathogenetic interactions.

Animals↗
PubMed1986

Radioimmunoassay typing gives a more precise definition of the HLA association of type 1 (insulin-dependent) diabetes.

The problem of the HLA association of Type 1 (insulin-dependent) diabetes was re-examined by testing Class II antigenic specificities detectable by radioimmunoassay. Established (DRw53, DQw1, DQw2, DQw3) as well as newly described (DC5, DCalpha3) specificities were typed. The data obtained suggest that the association with DR3 and DR4 is secondary to that with DQ specificities in linkage disequilibrium with DR3 and DR4.

Diabetes Mellitus, Type 1↗
PubMedDate not supplied

[Increased bile lithogenicity after simultaneous total parenteral nutrition and octrotide. A model of calcium palmitate Gallstones].

Gallbladder stasis and gallstone formation are well-known complications of both fasting-associated total parenteral nutrition (TPN) and long-term treatment with octreotide. Additive noxious effects to hepatobiliary function may develop when both therapies are given together as treatment of enteric fistulae. The aim of this study was to assess the risk of gallstone formation during treatment with TPN and octreotide separately and in combination. We studied four groups of New Zealand rabbits (n = 32) during a 2-week intervention period: 14 chow-fed controls; 6 fasted and TPN-fed; 6 chow-fed and administered octreotide, and 6 fasted and treated with both TPN and octreotide. After treatment, the bile duct was cannulated and the gallbladder and liver tissue were obtained for histological analysis. Hepatic and gallbladder bile were retrieved for microscopic examination and measurement of biliary lipids, bilirubin, calcium, total protein, and cholesterol nucleation time. The chemical composition of gallstones was also analyzed. The results of the study suggest that simultaneous administration of these two therapies in rabbits has additive effects on gallbladder stasis and bile lithogenicity. The administration of both treatments can play an important role in the formation of calcium palmitate gallstones in these animals.

Animals↗
PubMedDate not supplied

Vigorous achalasia: original description requires minor change.

UNLABELLED: Vigorous achalasia was described in 1957 as a subset of achalasia with a higher contraction amplitude (>37 mm Hg), minimal esophageal dilatation, prominent tertiary contractions, and higher incidence of chest pain. GOALS: Ascertain the existence of a distinct achalasia group based on manometric, radiographic, and clinical grounds. STUDY: The records of 209 idiopathic achalasia patients seen over a 9-year interval were reviewed for duration and frequency of dysphagia, chest pain, heartburn, weight loss, and nocturnal symptoms, as well as for treatment outcome. Manometric tracings were reanalyzed for lower esophageal sphincter pressure (LESP), LES residual pressure, distal esophageal contraction amplitude, and presence of repetitive waves. Patients were subsequently divided into classic (amplitude < or =37 mm Hg) and vigorous (amplitude >37 mm Hg) achalasia groups. Esophagrams were reassessed blindly for esophageal diameter both in the upright and recumbent positions and presence of lumen-occlusive tertiary contractions. RESULTS: One hundred forty-four classic and 65 vigorous achalasia patients were identified. These groups were similar in age and gender, as well as duration of symptoms. Chest pain was equally prevalent in both groups. Lower esophageal sphincter pressure was higher ( p < 0.01) and repetitive waves more common ( p < 0.0001) in the vigorous achalasia group. Upright esophageal diameter was smaller ( p = 0.0003) and tertiary contractions more frequent ( p = 0.0004) in this group. CONCLUSION: The original manometric and radiographic description of vigorous achalasia is accurate. The incidence of chest pain is similar to that of patients with classic achalasia.

Case-Control Studies↗