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J Sepulveda

Publications and source records attributed to J Sepulveda.

At least 19 recordsLinked to original sources
PubMed2002

Screening of gene expression profiles in gastric epithelial cells induced by Helicobacter pylori using microarray analysis.

BACKGROUND: H. pylori infection is a major risk factor in gastric cancer development. The availability of cDNA microarrays creates the unprecedented opportunity to examine simultaneously dynamic changes of multiple pathways affected by H. pylori infection. AIM: In this study we examined broad patterns of gene expression induced by H. pylori in the gastric cancer cell line 1739-CRL AGS cells in culture using the U95A microarray. METHODS: H. pylori were cocultured with AGS cells for 4, 12, 24 and 48 h. Total RNA was extracted and after labelling was used for detection of genes represented in the human U95A microarray set. Data analyses were performed using GeneChip and CLUSFAVOR software. RESULTS: Nearly 6000 genes present in the array were expressed by AGS cells. We report approximately 200 genes that showed the most marked changes. Our studies confirm the up-regulation of c-jun, jun-B, c-fos and cyclin D1 by H. pylori. We report for the first time the induction of the serine threonine kinase pim-1 and ATF3 by H. pylori infection of AGS cells. CONCLUSIONS: In this microarray analysis of gene expression induced by H. pylori in gastric epithelial cells, we identified a large number of unsuspected genes affected by H. pylori. Further, we show that unsupervised hierarchical cluster analysis can provide useful insight into the possible contribution of genes in specific pathways, based on their profile of expression.

Activating Transcription Factor 3↗
PubMed2001

High prevalence of low HDL cholesterol concentrations and mixed hyperlipidemia in a Mexican nationwide survey.

The prevalence of lipid abnormalities revealed in a survey done in 417 Mexican cities is described. Information was obtained on 15,607 subjects, aged 20 to 69 years. In this report, only samples obtained after a 9- to 12-h fast were included (2,256 cases: 953 men and 1,303 women). The population is representative of Mexican urban adults. Mean lipid concentrations were: cholesterol, 4.80 mmol/l; triglycerides, 2.39 mmol/l; HDL cholesterol, 1.00 mmol/l; and LDL cholesterol, 3.06 mmol/l. The most prevalent abnormality was HDL cholesterol below 0.9 mmol/l (46.2% for men and 28.7% for women). Hypertriglyceridemia (>2.26 mmol/l) was the second most prevalent abnormality (24.3%). Severe hypertriglyceridemia (>11.2 mmol/l) was observed in 0.42% of the population. Increased LDL cholesterol (> or =4.21 mmol/l) was observed in 11.2% of the sample. Half of the hypertriglyceridemic subjects had a mixed dyslipidemia or low HDL cholesterol. More than 50% of the low HDL cholesterol cases were not related to hypertriglyceridemia. Insulin resistance was found in 59% of them. In conclusion, the prevalence of hypoalphalipoproteinemia and other forms of dyslipidemia in Mexican adults is very high and it is among the highest previously reported worldwide.

Adult↗
PubMed1999

Monte Carlo sensitivity analysis of unknown parameters in hazardous materials transportation risk assessment.

The US Department of Transportation was interested in the risks associated with transporting Hydrazine in tanks with and without relief devices. Hydrazine is both highly toxic and flammable, as well as corrosive. Consequently, there was a conflict as to whether a relief device should be used or not. Data were not available on the impact of relief devices on release probabilities or the impact of Hydrazine on the likelihood of fires and explosions. In this paper, a Monte Carlo sensitivity analysis of the unknown parameters was used to assess the risks associated with highway transport of Hydrazine. To help determine whether or not relief devices should be used, fault trees and event trees were used to model the sequences of events that could lead to adverse consequences during transport of Hydrazine. The event probabilities in the event trees were derived as functions of the parameters whose effects were not known. The impacts of these parameters on the risk of toxic exposures, fires, and explosions were analyzed through a Monte Carlo sensitivity analysis and analyzed statistically through an analysis of variance. The analysis allowed the determination of which of the unknown parameters had a significant impact on the risks. It also provided the necessary support to a critical transportation decision even though the values of several key parameters were not known.

Hazardous Substances↗
PubMed1998

Population-based prevalence of symptomatic and asymptomatic astrovirus infection in rural Mayan infants.

Symptomatic and asymptomatic astrovirus infection was prospectively determined in a 3-year birth cohort of Mayan infants. Stool samples from 271 infants and 268 older siblings were tested for astrovirus, adenovirus 40/41, rotavirus and Salmonella, Shigella and Campylobacter species. Concurrent diarrhea, vomiting, fever, or anorexia were noted. Astrovirus was detected in 164 infants (61%) and 20 siblings (7%). Rotavirus (4%) and adenovirus 40/41 (13%) were isolated less frequently. Of all diarrheal episodes reported at a visit, 26% (78/305) were associated with astrovirus; 17% (78/452) of astrovirus infections were associated with diarrhea and 9% with other symptoms. Only diarrhea was associated with astrovirus infection (odds ratio, 1.4; 95% confidence interval [CI], 1.07-1.92; P = .01). Of infants with astrovirus, 70% shed at multiple visits over a period of 2-17 weeks (median, 5). The point prevalence of astrovirus infection was significantly higher among infants than siblings (relative risk, 6.18; 95% CI, 3.93-9.72; P < .0001, chi2). Astrovirus was identified throughout the year, peaked in March and May, and decreased in September. In this population, astrovirus was the most common enteric pathogen isolated; symptomatic infection was prevalent among infants.

Adenoviridae Infections↗
PubMed1998

An immunoenzymatic procedure for human apo B-containing particles quantification using monoclonal antibodies.

The present report describes a new monoclonal antibody-based enzyme immunoassay (ELISA) for the quantification of apolipoprotein (apo) B-containing particles in plasma. Native low-density lipoprotein (LDL) and a reference serum were utilized to prepare the standard curve. Three different antibodies to apo B-100--4A6E3, 6A10B10, and 2D9--all produced in our laboratory, were examined. The apparent affinity constants of the monoclonal antibodies (MAbs) 4A6E3, 6A10B10, and 2D9 were 2.9 x 10(9), 1.74 x 10(9), and 0.63 x 10(8), respectively. The standard curve was generated for an apo B-LDL range of 0.1 to 4.0 microg/ml. Evaluating the concentration of apo B-containing particles in plasma may allow for a more accurate assessment of the risk of coronary artery disease.

Antibodies, Monoclonal↗
PubMed1997

Host and viral factors affecting the decreased immunogenicity of Sabin type 3 vaccine after administration of trivalent oral polio vaccine to rural Mayan children.

Factors affecting immunogenicity of the first 2 doses of oral poliovirus vaccine (OPV) among unimmunized Mayan infants were prospectively evaluated. The relative impact of multiple variables, including mass or routine vaccination, concurrent enteric bacterial (salmonella, shigella, and campylobacter) and viral (adenovirus 40/41, astrovirus, nonpolio enteroviruses, and rotavirus) infections, interference among Sabin vaccine viruses, and preexisting poliovirus antibodies were studied. Sera were available from 181 infants after 2 OPV doses. Seroresponses were 86% to Sabin type 1, 97% to Sabin type 2, and 61% to Sabin type 3 vaccines. Mass versus routine vaccination and preexisting poliovirus antibodies did not affect immunogenicity. By multiple logistic regression analysis, fecal shedding of homologous Sabin strains was associated with increased seroresponses to all Sabin types, especially to Sabin type 3. Decreased OPV immunogenicity was primarily attributable to interference of Sabin type 3 by Sabin type 2. OPV formulations with higher doses of Sabin type 3 could improve immunogenicity among infants in developing countries.

Antibodies, Viral↗
PubMed1997

A monoclonal antibody-based enzyme immunoassay for the measurement of native and glycated apolipoprotein B-containing particles.

We describe the development of sandwich enzyme-linked immunosorbent assays designed to measure native and glycated apolipoprotein B containing particles in plasma. The assays utilize monoclonal antibodies anti native or glycated apo B-LDL for coating and a polyclonal anti apoB-LDL-peroxidase conjugate as the detecting antibody. The method is specific, sensitive and precise. The intra assay coefficient of variation for the plasma native and glycated apolipoprotein B-containing particles was determine to be 7.8% and 7.5%, respectively. The method described can provide specific and reproducible determinations of apoB and glycated-apoB containing particles in plasma; it will be of great interest in the evaluation of atherosclerotic risk in dyslipoproteinemic states in diabetic and non-diabetic subjects.

Antibodies, Monoclonal↗
PubMed1995

Development of monoclonal antibodies for the selective isolation of human plasma apolipoprotein A-containing particles.

Monoclonal antibodies (MAbs) to human plasma apolipoprotein A-I (apo A-I), denoted FF9 and 6B9, and apolipoprotein A-II (apo A-II), 3F5, were developed to be used in an immunoaffinity chromatography procedure to isolate lipoprotein particles Lp A-I and Lp A-I:A-II. MAb FF9 and MAb 6B9 reacted with apo A-I and high-density lipoprotein (HDL) while MAb 3F5 was directed to apo A-II and HDL. The apparent affinity constant (Kapp) for apo A-I of the MAb FF9 was higher (2 x 10(7) M-1) than that of 6B9 (5 x 10(6) M-1). MAb 3F5 recognized the apo A-II with a Kapp value of 1 x 10(9) M-1. The isolated lipoparticles Lp A-I and Lp A-I:A-II will be used to standardize an immunoassay for the measurement of these apo A-I-containing lipoprotein particles in human plasma.

Animals↗
PubMed1994

Mediation of suppression of c-fos transcription in rasT24-transformed rat cells by a cis-acting repressor element.

Prolonged expression of activated ras mutants resulted in both neoplastic transformation and suppression of serum-induced c-fos expression in Rat1 fibroblasts. Expression of other serum-inducible genes, including c-jun and beta-actin, was not suppressed in ras-transformed Rat1 cells, indicating that these effects are specific for c-fos and that growth-factor signal transduction pathways remain essentially intact. Run-on transcription studies indicated that c-fos transcription was blocked at the level of initiation in these cells. Transient transfection studies using 360 bp from the wild-type c-fos promoter as well as a series of mutated c-fos promoter fragments linked to the chloramphenicol acetyltransferase gene indicated that repression of c-fos was mediated by approximately 49 bp immediately upstream of the dyad symmetry element (DSE). Deletion of this region, referred to as the upstream repressor region (URR), restored serum inducibility to the c-fos promoter in ras-transformed cells. In contrast, suppression of c-fos transcription was not affected by either deletion of 240 bp between the DSE and the TATA element or by base-substitution mutations that inactive the ternary complex factor and fos-AP-1-like binding sites. In addition, in vitro competition studies indicated that ras-transformed cells express one or more repressor factors that interact with as-yet-unidentified elements within the c-fos promoter (possibly the URR) and block serum induction of c-fos. These findings suggest that prolonged expression of activated ras results in the activation of one or more as-yet-unidentified proteins that suppress transcription of the c-fos gene by interacting with the URR.

Animals↗
PubMed1993

Cholesterol increase in mitochondria: its effect on inner-membrane functions, submitochondrial localization and ultrastructural morphology.

The effect of cholesterol incorporation on some functions of the mitochondrial inner membrane and on the morphology of rat liver mitochondria was studied. Basal ATPase and succinate dehydrogenase activities remained unchanged after cholesterol was incorporated into the mitochondria; however, uncoupled ATPase activity was partially inhibited. The presence of several substrates and inhibitors did not change the amount of cholesterol incorporated, which was localized mostly in the outer membrane. Electron-microscope observations revealed the presence of vesicles between the outer and inner membranes; these vesicles increased in number with the amount of cholesterol incorporated. The data suggest that cholesterol induces the formation of vesicles from the outer membrane, and modifies the activity of stimulated ATPase.

Adenosine Triphosphatases↗
PubMed1993

Immunization against porcine cysticercosis in an endemic area in Mexico: a field and laboratory study.

An antigenic extract from Taenia solium metacestodes was evaluated for immunogenicity in pig populations from a large area of endemic porcine cysticercosis in the State of Guerrero, Mexico. A total of 3,295 pigs from 18 villages were immunized with a single dose of 250 micrograms of protein administered intramuscularly. Systematic immunization was also performed on pigs (1,076 immunizations) from two of the villages with the highest percentages of cysticercosis. A year after immunization, porcine cysticercosis decreased from 4.8% and 5.4% to 0%. Immunity against the T. solium metacestode was estimated in vitro by measurements of 3H-thymidine uptake and inhibition of leukocyte migration. Peripheral blood lymphocytes from immunized cysticercotic (pigs that had cysticercosis prior to immunization), cysticercotic immunized (pigs that acquired cysticercosis after immunization), and normal control pigs incorporated 3H-thymidine better than lymphocytes from cysticercotic pigs when stimulated with concanavalin A. A significant inhibition in the leukocyte migration inhibition test was also found in leukocytes from immunized cysticercotic pigs (P < 0.01). Histopathologic studies revealed granuloma formation surrounding the metacestodes of the immunized cysticercotic and cysticercotic immunized pigs. These metacestodes exhibited several stages of destruction. Large numbers of eosinophils were frequently observed in a close association with the degeneration and destruction of parasites. Metacestodes in control cysticercotic pigs were intact and surrounded by a minor inflammatory reaction. Finally, the rate of in vitro evagination of scolices was high in metacestodes obtained from cysticercotic pigs and low or absent in those from immunized pigs (P < 0.01).

Animals↗
PubMed1992

Sexual behavior and status for human immunodeficiency virus type 1 among homosexual and bisexual males in Mexico City.

The authors examined sexual behaviors, the seroprevalence of human immunodeficiency virus type 1 (HIV-1), and condom use among 2,314 homosexual and bisexual men tested during 1988-1989 at the AIDS (acquired immunodeficiency syndrome) National Center in Mexico City. Bisexuals constituted 24% of the sample; the seroprevalence rate was lower for bisexuals than homosexuals (21 vs. 34%). In logistic regressions, HIV-1 seropositivity was independently related to age, education, pattern of insertive/receptive behavior in anal sex, lifetime number of male sex partners, having sex with someone with AIDS, homosexual versus bisexual behavior, and a history of condyloma. The same logistic regressions were found to fit bisexuals and homosexuals. The rate of HIV-1 was reduced in individuals who indicated always requiring their partners to use a condom when practicing receptive anal sex (1% of the total). The most common practice for both homosexuals and bisexuals was "mixed" behavior (i.e., both insertive and receptive anal sex); this was also the practice with the highest risk. Bisexuals practiced both vaginal and anal sex with women and reported little condom use. The substantial seroprevalence among bisexuals, their frequent sexual contact with women, and their low rate of condom use imply a continuing role as a bridge of infection to females. Whether this risk will lead to a sustained heterosexual epidemic remains to be determined.

Adolescent↗
PubMed1992

Myeloid differentiation of HL-60 cells induced by anti-tumor drug 3-nitrobenzothiazolo[3,2-a]quinolinium.

Drugs which elicit cell differentiation might have an important role in the treatment of leukemias and other neoplasias. Various chemotherapeutic agents promote leukemic cell differentiation. The HL-60 cell line is a useful model to study in vitro myeloid differentiation. Sublethal concentrations of 3-nitrobenzothiazolo[3,2-a]quinolinium (NBQ), an antitopoisomerase II drug, were given to HL-60 cells from one to five days to evaluate its capacity to induce differentiation. NBQ-induced HL-60 cells reduced nitroblue tetrazolium (NBT), increased MY-4 receptors, increased phagocytic activity and displayed the granulocytic morphology. Flow cytometric DNA analysis of NBQ-induced cells revealed an arrest in the G1 phase a reduction in the relative percentage of cells in S and G2+M phases. Our results suggest that NBQ induces an S-phase specific differentiation of HL-60 cells comparable to that previously described with dimethyl sulfoxide and retinoic acid. NBQ and its analogs, as differentiation inducers, may have potential utility as a novel therapeutic modality for leukemias.

Cell Cycle↗
PubMed1990

Immunization of six-month-old infants with different doses of Edmonston-Zagreb and Schwarz measles vaccines.

Because measles causes an estimated 2 million deaths per year among children in developing countries, including a substantial proportion of infants less than nine months old--the age at which vaccination is recommended--there has been interest in using different strains of vaccine and higher doses to achieve immunization of younger infants. We conducted a randomized trial of three different doses of Edmonston-Zagreb and of Schwarz measles vaccines in infants to evaluate the effect of the strain and dose of vaccine on the serologic response and acute adverse reactions to vaccination. Six-month-old infants received a standard, medium, or high dose of one of the vaccines, and nine-month-old infants received a standard dose. Antibody levels were measured before and after vaccination, by means of a plaque-reduction neutralization assay, in 1061 six-month-olds and 299 nine-month-olds. Edmonston-Zagreb vaccine produced higher rates of seroconversion and seropositivity than comparable doses of Schwarz vaccine. Among the six-month-old infants, the seroconversion rate 18 weeks after vaccination with the standard dose of Edmonston-Zagreb vaccine was 92 percent, that with the medium dose was 96 to 97 percent, and that with the high dose was 98 percent; the rates for the corresponding doses of Schwarz vaccine were 66 percent, 76 percent, and 91 percent, respectively. Higher seroconversion rates were observed with an increase in the dose of either Edmonston-Zagreb (P less than 0.01) or Schwarz (P less than 0.001) vaccine. The seroconversion rates produced by high and medium doses of Edmonston-Zagreb vaccine in six-month-olds were equal to or significantly higher than the rate produced by a standard dose of Schwarz vaccine in nine-month-olds (87 percent). Clinical adverse reactions were not associated with the strain or dose of a vaccine. We conclude that Edmonston-Zagreb vaccine is more immunogenic than Schwarz vaccine in infants and can induce effective immunization against measles at six months of age.

Age Factors↗
PubMed1990

Use of the RapID-ANA system and sodium polyanetholesulfonate disk susceptibility testing in identifying Haemophilus ducreyi.

Haemophilus ducreyi has traditionally been difficult to identify. We have utilized simple test methods to identify 19 fresh isolates obtained during a recent outbreak of chancroid in Houston and six strains of H. ducreyi from other outbreaks. Tests were performed from growth on chocolate agar after 48 h of incubation at 35 degrees C with increased humidity and CO2. All isolates exhibited typical colonial morphology and Gram stain. Isolates were catalase negative and oxidase and nitrate positive (in enriched broth). The RapID NH system failed to identify these strains because of negative reactions with alkaline phosphatase and nitrate reductase. However, by using the RapID-ANA system, all strains were positive for alkaline phosphatase and arginine, glycine, and serine aminopeptidases. Their biochemical profiles were distinct from those obtained with 66 strains representing 13 species similar to H. ducreyi. We also investigated the use of sodium polyanetholesulfonate (SPS) disk susceptibility to identify and differentiate H. ducreyi from other species. All H. ducreyi isolates were susceptible, as evidenced by the presence of a zone of inhibition with an average size of 15 mm around the SPS disk. With the exceptions of Neisseria gonorrhoeae, Gardnerella vaginalis, and Capnocytophaga spp., no other strain showed any evidence of inhibition. The latter three organisms can be easily differentiated from H. ducreyi by various features including reactions in the RapID-ANA. We conclude that, by considering simple growth and biochemical characteristics, SPS susceptibilities, and reactions in RapID-ANA, it is possible for more clinical laboratories to definitively identify this organism.

Bacteriological Techniques↗
PubMed1977

Neural pathway mediating somatic evoked responses in the caudate nucleus of cats.

The course of somatic afferents to caudate nucleus (CN) was investigated. In curaized cats discrete lesions in intralaminar nuclei, n. centralis medialis (NCM) affect evoked response (ER) in CN to radial nerve stimulation. NCM lesions totally abolish these somatic responses, while after subthalamic lesions ER appear only when a high stimulus intensity is used. Lesions in the specific relay nuclei, ventralis posterior lateralis (VPL) have no effect on somatic ER in CN. Barbiturates (10 mg/kg) abolish somatic ER in CN. Stimulation of the ponto-mesencephalic reticular formation (RF) in a region where visual and somatic responses are recorded shows lowest threshold values for eliciting evoked responses in NCM and CN. The potentials in CN to RF stimulation are restricted to this nucleus and disappear in the internal capsule.

Afferent Pathways↗