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Biomedical subjects

A Muñoz

Publications and source records attributed to A Muñoz.

At least 451 records · Page 25Linked to original sources
PubMed1989

Endodermal sinus tumor of the ovary: a paradoxical response to chemotherapy.

A patient with ovarian endodermal sinus tumor metastatic to the liver responded unusually to chemotherapy. She experienced histologically documented regression of all intraperitoneal disease with the exception of the liver metastases when given vinblastine, bleomycin, and cisplatin. She eventually died of liver failure. A review of patients with ovarian endodermal sinus tumor who either presented with initial liver metastases or had recurrent disease in the liver leads us to conclude that the liver is a preferential site for spread, that liver metastases carry an ominous prognosis, and that failure to see prompt liver metastatic tumor response after systemic chemotherapy should signal a need for a more aggressive therapeutic approach to the liver lesions.

Adult↗
PubMed1989

Familial factors related to lung function in children aged 6-10 years. Results from the PAARC epidemiologic study.

Familial factors related to lung function between six and 10 years of age have been studied among 1,160 children whose both parents were examined in 1975 in the French PAARC (Pollution Atmosphérique et Affections Respiratoires Chroniques) Cooperative Study. The three indices FVC (forced vital capacity), FEV1 (forced expiratory volume in one second), and FEF25-75 (forced expiratory flow between 25 and 75 per cent of the vital capacity) were studied after adjustment for sex, town, age, and height (and weight for children's FVC and FEV1). Maternal (but not paternal) smoking was associated with a significant decrease in FEV1 and FEF25-75, but not in FVC. Familial resemblance was observed for all indices between children and parents and between siblings. None of the environmental factors considered (i.e., parental smoking or education) or body habitus explained the familial resemblance observed. Conversely, after taking into account the aggregation between siblings, associations between children's lung function and parental characteristics (smoking, lung function) remained significant. Parental-children correlations exhibited an increasing temporal trend with increasing age of the children. All but one correlation for FVC, FEV1, and FEF25-75 residuals of children with mothers' residuals were higher in the oldest age group compared with the youngest age group at the 0.10 level. Furthermore, correlations between siblings of opposite sex were significantly lower than correlations between siblings of like sex, especially for FEV1/FVC and FEF25-75/FVC. Results suggest that different growth patterns between boys and girls may be a critical factor in the study of lung function familial resemblance.

Age Factors↗
PubMed1989

Acquired immunodeficiency syndrome (AIDS)-free time after human immunodeficiency virus type 1 (HIV-1) seroconversion in homosexual men. Multicenter AIDS Cohort Study Group.

To estimate the time interval between human immunodeficiency virus type 1 (HIV-1) seroconversion and acquired immunodeficiency syndrome (AIDS) diagnosis in homosexual men, prospective incident cohorts are difficult to obtain and, if assembled, provide few events owing to the long incubation time. Although seroprevalent cohorts are numerous in size and events, the information is limited due to the unknown times since seroconversion. To combine the information provided by 1,628 seroprevalent men (304 AIDS cases) and 233 seroconverters (12 AIDS cases) being followed in a multicenter study since 1984, the postseroconversion changes in hematologic variables occurring in the incident cohort were used to develop a model that allowed for the imputation of the unknown times since seroconversion for the seroprevalent cohort. Nonparametric life table methods incorporating truncation and censoring were applied for the estimation of the probability distribution of the AIDS-free time after seroconversion. The precision of the estimates was evaluated using bootstrap methods. The analysis suggested that AIDS is unlikely (less than 0.5%) in the first year; 78% of seropositive homosexual men remain AIDS-free 60 months after seroconversion; and the AIDS incidence increases for months 12-36 and levels off at 38 per 1,000 person-semesters for months 42-60. The nonparametric estimate of the incidence rate suggests a median AIDS-free time of 11 years, which is longer than previous estimates based on parametric models.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Evaluation of different plating media used in the isolation of salmonellas from environmental samples.

Different serotypes of salmonellas were compared for selectivity and efficiency of recovery using 11 plating media. No optimal growth was obtained after 24 h incubation in any of the media, but after 48 h, brilliant green, brilliant green-phenol red-lactose-sucrose, bismuth sulphite, xylose-lysine-deoxycholate and Hektoen enteric agars showed optimal recovery of all the salmonella serotypes. Xylose-lysine-deoxycholate and brilliant green-phenol red-lactose-sucrose agars were the most selective media for all salmonella serotypes. Addition of 10 micrograms/ml of sodium novobiocin to the tryptic soy-xylose-lysine and tryptic soy-brilliant green agars significantly improved their selectivity but reduced or inhibited the growth of some salmonella serotypes, including Salmonella typhi. Xylose-lysine-deoxycholate agar gave the highest recovery percentage of stressed salmonellas with a double-agar layer technique. Good recovery was also obtained on brilliant green-phenol red-lactose-sucrose, tryptic soy-brilliant green, tryptic soy-brilliant green-novobiocin, tryptic, soy-xylose-lysine and tryptic soy-xylose-lysine-novobiocin agars. Salmonella-shigella agar was the least efficient medium for the recovery of salmonellas under stress-induced or non-stressed conditions.

Culture Media↗
PubMed1989

Temporal trends of human immunodeficiency virus type 1 (HIV-1) infection among inmates entering a statewide prison system, 1985-1987.

Acquired immune deficiency syndrome (AIDS) became the leading cause of death among Maryland State prisoners in 1985. To identify the prevalence, risk factors, and temporal trends for infection with the human immunodeficiency virus type 1 (HIV-1) in the statewide prison system, excess sera were obtained from incoming male inmates during specified periods between April and June 1985, 1986, and 1987. Correctional medical personnel also provided demographic variables of age, race, offense category, sentence, jurisidiction, and an indicator of intravenous drug use. Once rendered anonymous, specimens were assayed for antibody to HIV-1, using ELISA and Western blot techniques. For data from April to June 1985, 1986, and 1987, the crude prevalence of anti-HIV-1 was 7.1, 7.7, and 7.0%, respectively. Although one-third of incoming inmates were identified as intravenous drug users (IVDUs), the drug use variable was missing for 70% of the 1985 sample, and 40% of the 1986 sample. Several strategies were used to examined temporal trends in the context of missing data. Univariate analyses suggested no substantial change over time for either HIV-1 seroprevalence or risk of infection among IVDUs.(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMed1988

Effect of maternal and infant covariates on sibship correlation in birth weight.

Birth weight on 12,644 singleton infants from 6,196 sibships born in Maryland between 1980 and 1984 were used to estimate the effects of nine maternal and infant covariates on the sibship correlation in birth weight. Assuming a homogeneous correlation across all families, the estimated intraclass correlation was 0.4664 (+/- 0.0099). This high sibship correlation makes it possible to predict, with reasonable accuracy, the birth weight of a child given information on previous sibs, as well as covariates on the mother and/or infant pertinent to a given pregnancy. The reduction in variance associated with incorporating information on the nine covariates used here was approximately equal to that obtained by conditioning on a single previous sib. Testing for heterogeneity in correlation among different groups of families showed that a crude measure of parity (first live birth vs. other), time between births, mother's marital status, and maternal age at the birth of the last child significantly influenced the sibship correlation in birth weight.

Adult↗
PubMed1988

Characterization of the hormone-binding domain of the chicken c-erbA/thyroid hormone receptor protein.

To identify and characterize the hormone-binding domain of the thyroid hormone receptor, we analyzed the ligand-binding capacities of proteins representing chimeras between the normal receptor and P75gag-v-erbA, the retrovirus-encoded form deficient in binding ligand. Our results show that several mutations present in the carboxy-terminal half of P75gag-v-erbA co-operate in abolishing hormone binding, and that the ligand-binding domain resides in a position analogous to that of steroid receptors. Furthermore, a point mutation that is located between the putative DNA and ligand-binding domains of P75gag-v-erbA and that renders it biologically inactive fails to affect hormone binding by the c-erbA protein. These results suggest that the mutation changed the ability of P75gag-v-erbA to affect transcription since it also had no effect on DNA binding. Our data also suggest that hormone-independent activity of P75gag-v-erbA provided a selective advantage to the avian erythroblastosis virus during the original selection for a highly oncogenic strain of the virus.

Animals↗
PubMed1988

Malnutrition and diarrhea. A longitudinal study among urban Mexican children.

To address the hypothesis that malnutrition is associated with an increased risk of diarrhea, the authors identified a cohort of 284 Mexican children less than two years of age in order to equally represent different degrees of nutritional status. Nutritional status, defined anthropometrically, was measured at baseline and every three months for a total follow-up period of one year. The occurrence of diarrhea was assessed by weekly home visits. Among the combinations of weight and length examined, weight for age was the strongest predictor of subsequent diarrhea during a three-month interval. Among normally nourished children, the incidence of diarrhea was 3.3 episodes per year; among those mildly malnourished, 3.7 episodes per year (relative risk (RR) = 1.1); and among the moderately malnourished, 6.0 episodes per year (RR = 1.8). Adjustment for demographic, seasonal, and socioeconomic variables only slightly reduced this association. Nutritional status was most strongly related to the occurrence of two or more episodes during a three-month follow-up interval, and this effect was most clearly seen among children with diarrhea in the preceding interval. In a multiple logistic analysis that included potentially confounding variables as well as an autoregressive term to account for the nonindependence of repeated observations, the relative risk of two or more episodes of diarrhea during an interval was 1.8 (95% confidence interval 1.1-2.9) for moderately malnourished children compared with those who were normally nourished or mildly malnourished. These data lend support to the hypothesis that malnutrition predisposes to the occurrence of diarrhea among young children.

Diarrhea, Infantile↗
PubMed1988

Response of preterm infants to diphtheria-tetanus-pertussis vaccine.

The American Academy of Pediatrics recommendation that immunization of preterm infants with diphtheria-tetanus-pertussis (DTP) vaccine should begin at 2 months after birth, regardless of gestational age, is based on limited data. A prospective study was conducted to determine the immunogenicity and safety of DTP vaccine in preterm infants. One hundred ten preterm and 146 full term infants received doses of DTP at 2, 4 and 6 months after birth. Adjusted analysis of the antibody responses indicated that after three doses mean titers among preterm infants to each vaccine component were comparable to those of full term infants. Adjusted analysis of the incidence of adverse events indicated that the risk of adverse events in preterm infants was not significantly higher than that in full term infants. DTP vaccine is immunogenic and safe in preterm infants when the series is initiated at 2 months after birth, and this study supports the current recommendation of the American Academy of Pediatrics.

Antibody Formation↗
PubMed1988

A retrospective cohort study of lung cancer and diesel exhaust exposure in railroad workers.

The risk of lung cancer as a result of exposure to diesel exhaust from railroad locomotives was assessed in a cohort of 55,407 white male railroad workers 40 to 64 yr of age in 1959 who had started railroad service 10 to 20 years earlier. The cohort was traced until the end of 1980, and death certificates were obtained for 88% of 19,396 deaths; 1,694 lung cancer cases were identified. Yearly railroad job from 1959 to death or retirement was available from the Railroad Retirement Board, and served as an index of diesel exhaust exposure. Directly standardized rates and a proportional hazards model were used to calculate the relative risk of lung cancer based on work in a job with diesel exhaust exposure beginning in 1959. A relative risk of 1.45 (95% CI = 1.11, 1.89) for lung cancer was obtained in the group of workers 40 to 44 yr of age in 1959, the group with the longest possible duration of diesel exposure. The cohort was selected to minimize the effect of past railroad asbestos exposure, and analysis with workers with possible asbestos exposure excluded resulted in a similarly elevated risk. Workers with 20 yr or more elapsed since 1959, the effective start of diesel exposure for the cohort, had the highest relative risk. These results taken in conjunction with other reported results support the hypothesis that occupational exposure to diesel exhaust results in a small but significantly elevated risk for lung cancer.

Adult↗
PubMed1988

Patterns of CD4+ cell changes after HIV-1 infection indicate the existence of a codeterminant of AIDS.

Successive interval slopes of CD4+ cells each constructed from levels at three consecutive 6 month visits were compared over 3 years of follow-up among 565 persistently HIV-1 antibody-positive, 326 persistently antibody-negative, and 51 seroconverting homosexual men who had at least 500 CD4+ cells/mm3 at baseline and completed the first three 6 month visits. "Change" was defined as a difference between two successive interval slopes. Sixty-two percent of seroconverters meeting these criteria experienced a shift in one or more of their successive CD4+ interval slopes, the majority (56%) from a level slope to a negative slope (decreasing numbers of CD4+ cells), a significantly greater proportion than that observed among seronegatives (30%, p less than 0.0001). Fifty-eight percent of the seropositives maintained level interval slopes over the 3 years of follow-up. The majority (59%) of those men experiencing a shift went from a level to a negative interval slope, a significantly greater proportion than observed among seronegatives (30%, p less than 0.0001). The observed patterns of change in interval slopes are consistent with the laboratory observation that CD4+ cells must be activated to replicate HIV-1. The use of the interval slope strategy provides a method to identify a temporal focal point at which to examine possible codeterminants that trigger the production of HIV-1 and the subsequent decline in CD4+ cells.

AIDS Serodiagnosis↗
PubMed1988

Predictors of decline in CD4 lymphocytes in a cohort of homosexual men infected with human immunodeficiency virus.

Longitudinal data on four visits scheduled at 6 month intervals were available on a cohort of 1,827 homosexual men who were human immunodeficiency virus (HIV) seropositive at entry. To identify predictors of the rate of decline of CD4 T-lymphocytes, we used an autoregressive model that relates CD4 counts to predictor variables, while adjusting for previous CD4 counts. Significant predictors of steeper decline of CD4 counts were high CD8 count, low hemoglobin, low platelets, high serum IgA, high cytomegalovirus (CMV) antibody, and low HIV antibody. Using the fitted model, a subject with an initial deficit of 314 CD4 cells (median value of study sample) with respect to seronegative subjects and with average values in all other predictors is estimated to lose approximately 53 cells in a 6 month period (95% C.I. = 45-61 cells). Contrasting this estimate to the one obtained with similar methods in intravenous drug users, it is suggested that a faster rate of decline is present among i.v. drug users. This analysis provides evidence that several covariates in addition to previous number of CD4 counts have significant predictive power for estimating the decline in CD4 counts in HIV seropositive subjects.

AIDS Serodiagnosis↗
PubMed1987

Predictive value of minor anomalies: II. Use in cohort studies to identify teratogens.

Cohort studies of putative human teratogens can identify the full spectrum of phenotypic effects, including both major malformations and minor anomalies. Cohort studies which include the much more common minor anomalies make it possible to use a relatively small number of exposed and unexposed infants to identify an increase in the frequency of malformations. We evaluated this use of minor anomalies in a cohort study of newborn infants who had been exposed in utero to three putative teratogens: insulin-dependent diabetes mellitus in the mother and the use of the anticonvulsant phenytoin and exogenous sex hormones by the mother. In addition, the reproducibility of identifying minor anomalies was tested by comparing the results of examinations by two independent observers of 444 unexposed infants. The frequency of minor anomalies was increased among infants of diabetic mothers. However, the reproducibility of identifying minor anomalies was poor. We conclude that the examination of teratogen-exposed infants for minor anomalies cannot be used in epidemiologic studies of putative teratogens unless special efforts are made to maximize consistency in the identification of these features.

Abnormalities, Drug-Induced↗