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Biomedical subjects

A Muñoz

Publications and source records attributed to A Muñoz.

At least 523 records · Page 29Linked to original sources
PubMed1978

Pulmonary and hepatic echinococcosis in children.

Eighty children suffering from pulmonary and/or hepatic echinococcosis are reported. The epidemiological and parasitological aspects are reviewed, and the importance of the radiological signs and differential diagnosis are emphasized.

Adolescent↗
PubMed1977

Enteropathogenic E. coli gastroenterocolitis in neonates treated with fosfomycin.

The effect of calcium salt of fosfomycin in the treatment of 43 neonates suffering from acute gastroenterocolitis produced by enteropathogenic E. coli is evaluated. The minimal inhibitory concentration of these E. coli was, generally, lower than 128 mug/ml. Dosages of 150-200 mg/kg body weight/day were administered orally every 8 h. This treatment lasted for 4 days only. Clinical evolution was favorable in 38 (88%) babies and bacteriological evolution in 30 (70%). In eight cases a different flora to the initial was selected during the treatment with fosfomycin. None of the cases treated showed any toxic alteration attributed to the antibiotic.

Acute Disease↗
PubMed1976

[Tumors of the endodermal sinus (author's transl)].

Seven cases of tumors of the endodermal sinus are reviewed. This is a highly malignant germinal tumor, arisen from extraembrionary cell differentiation. It is different both biologically and pathologically from sacrocoxigeal teratoma. There are no survivors in these series. All seven patients have been surgically treated chemotherapy has been used in four, and X-ray therapy in two. It is noteworthy that alpha-phetoprotein is present in patients with this type of tumor. This fact can be used both in diagnosis of the tumor and of its recurrence.

Adenoma↗
PubMedDate not supplied

Parametric models to assess tracking of categorical high-risk sexual behaviour for HIV infection.

Prevalence and tracking (within-individual correlation) of high-risk behaviour measured in longitudinal studies provide a complementary description of how behaviour is maintained over time. Without tracking, when population prevalences are approximately constant over time, the steadiness of the aggregate pattern is likely to mask the dynamic changes of the response occurring on an individual level. In this paper, a parametric model is proposed for the estimation of these features when the observed response is a time-stationary categorical measurement. The model extends the standard Dirichlet-multinomial model in the spirit of Prentice (1986, JASA) by allowing both negative and positive correlation among repeated categorical measurements. In addition, both the marginal category probabilities and the tracking can be modelled as a function of individual-level covariates. Details regarding likelihood based estimation and inference are provided and illustrated with data from the Multicenter AIDS Cohort Study (MACS).

Cohort Studies↗
PubMedDate not supplied

Models for the incubation of AIDS and variations according to age and period.

The objective of the methods proposed is to provide a parametric model for the incubation of AIDS and to use the chosen parameterization to test for the effect of age at seroconversion, and, after adjusting for markers of immunosuppression, to assess variations in periods corresponding to different levels of use of AIDS therapies at the population level. We compared the fit of Weibull, log-normal and three-parameter logistic models incorporating truncation in prevalent cohort and interval censored data. We showed the advantages by restricting the analysis to follow-up durations of greater than five years to improve estimation of the tail of the distribution for the prediction of long-term survivors. We applied the proposed methods to the combination of 1649 seroprevalent and 476 seroconverters with 1022 and 177 AIDS cases, respectively, who have been followed in the Multicenter AIDS Cohort Study (MACS) up to April 1995. Differences according to age at seroconversion are quantified in terms of relative percentiles and their associated 95 per cent confidence intervals were calculated using methods of multiple imputation. Using the proposed methods, we found that the log-normal model provides a fit as good as the three-parameter logistic; both are close to the non-parametric estimate and are significantly better than the fit of the Weibull model. We found that the older the age at seroconversion, the shorter the time to AIDS (relative percentile = 0.72 for age > or = 40 versus age < 25), and that the incubation of AIDS in calendar periods where treatment has been widely administered has been significantly longer among individuals with low CD4 cell counts.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

The use of an autoregressive model for the analysis of longitudinal data in epidemiologic studies.

Korn and Whittemore have presented methods for analyzing longitudinal data where the number of observations per individual is large relative to the number of variables considered for each subject. However, this is often not the case in epidemiologic studies, since one usually collects data at relatively few time points, and the quantity of data collected for each individual at each time point is typically extensive. We present here an autoregressive model for analyzing longitudinal data of this type for the case of a continuous outcome variable. Some of the important features of this model are that one can in the same analysis, consider both independent variables that are time-dependent and those that are fixed over time, partially use data for an individual where some examinations are missing, assess relationships between changes in outcome and exposure over short periods of time, use ordinary multiple regression methods. Anderson has considered this type of model, but, to our knowledge, the model has never been applied to biostatistical problems. We illustrate these methods with data from a longitudinal study that seeks to identify the role of personal cigarette smoking on changes in pulmonary function in children.

Adolescent↗
PubMedDate not supplied

The effectiveness of interventions on incubation of AIDS as measured by secular increases within a population.

Methods are developed to estimate and test for the impact of intervention use on a population's survival function (time to AIDS). Each participant's history is divided into J + 1 components: omega 0 occurring before the intervention is available and omega 1 to omega J occurring later, as the intervention becomes successively more available. Distribution free truncated Kaplan-Meier models based on time since exposure fit separately to the risk sets/outcomes in omega 0 to omega J directly show the changing patterns of survival. Multivariate proportional hazards models can be used to adjust for covariates. Application of these methods indicates that availability of proven anti-AIDS interventions may have delayed time to AIDS by 8 months in an educated HIV-1 infected homosexual cohort with good access to medical care.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

The human cranial remains from Gran Dolina Lower Pleistocene site (Sierra de Atapuerca, Spain).

In this article we study the cranial remains of the late Lower Pleistocene human fossils from Gran Dolina (Sierra de Atapuerca, Spain), assigned to the new species Homo antecessor. The cranial remains belong to at least five individuals, both juveniles and adults. The most outstanding feature is the totally modern human morphology of the very complete face ATD6-69, representing the earliest occurrence of the modern face in the fossil record. The Gran Dolina fossils show in the face a suite of modern human apomorphies not found in earlier hominids nor in contemporary or earlier Homo erectus fossils. There are also traits in the Gran Dolina fossils shared with both Neandertals and modern humans, which reinforce the hypothesis that Neandertals and modern humans form a clade, and that the Gran Dolina fossils are a common ancestor to both lineages.

Age Determination by Teeth↗
PubMedDate not supplied

Differentiation of Candida guilliermondii varieties by lectin-like substances from marine algae.

Lectin-like substances of 54 marine algae, corresponding to 30 red algae and 24 brown algae, were studied to estimate the agglutination activity against Candida guilliermondii. Extracts of Dictyopteris membranacea, Bifurcaria bifurcata, Halidrys siliquosa, Ascophyllum nodosum, Fucus serratus and F. spiralis algae showed selective agglutinating activities for C. guilliermondii "sensu stricto" and some of its varieties. According to their response to agglutination (positive or negative), certain algal extracts enabled the differentiation of varieties of C. guilliermondii independently of the titre values. Three extracts of brown algae were sufficient to identify 4 varieties of C. guilliermondii. The results suggest that lectin-like substances from marine algae may be valuable reagents as assistant tools for the identification of yeast strains.

Agglutination↗
PubMedDate not supplied

Risk factors associated with malaria infection in an urban setting.

Incidence of malaria in urban settings is a growing concern in many regions of the world and individual risk factors need to be identified to appropriately adjust control strategies. We carried out a cross-sectional study in 1993/94 in an urban area of the largest port of the Pacific Coast of Colombia, where transmission has had an upward trend over the past 5 years. Prevalence of malaria infection was estimated in areas of the city with the highest incidence of disease, and the association between some characteristics of the population and the risk of malaria infection was assessed. Prevalence of malaria infection was 4.4% among the 1380 studied people and we found that it decreased with older age, and with knowledge of disease and preventive measures directed to elimination of breeding sites. In addition, the infection was positively associated with exposure to the forest (P < 0.05), although most of the cases (57/61, 93%) were likely to have been acquired in the urban area. We also found that individuals receiving antimalarial treatment in the previous month had around twice the risk of being infected as compared with those without treatment. In addition, our results suggest that use of bednets could not be a very effective protective measure in settings such as that of our study, and that environmental interventions may be needed to decrease the risk of infection.

Adolescent↗
PubMedDate not supplied

The requirements for stable metallothionein clusters examined using synthetic lobster domains.

Metallothioneins (MTs) are small, cysteine-rich proteins which detoxify xenobiotic metals such as cadmium (Cd) and mercury (Hg). In crustaceans and mammals they consist of two independent domains which are folded around metal-thiolate clusters. MT clusters of different origins, exhibiting distinct, highly conserved cysteine positions on their sequences, show differences in metal-cysteine coordination and reactivity. Lobster-MT, containing two Cd3 beta domains, is an important model for structure-function relationships among the clusters. The influence of (1) the position of the cysteine residues and (2) steric and electrostatic effects of neighboring amino acids on the folding and stability of MT cluster were investigated. Thus, the native lobster beta C and beta N domains (each having nine cysteines and binding three M2+ ions) and a modified domain Cd3 beta C-->N, in which the cysteines of the C-terminal domain were relocated to match the positions of those in the N-terminal domain, were chemically prepared and characterized. The synthetic native domains (Cd3 beta C and Cd3 beta N) were found to exhibit spectroscopic properties, metal-binding affinities and kinetic reactivity similar to the holo-protein. However, the modified Cd3 beta C-->N domain was unusually reactive and in the presence of Chelex, metal chelation resin, aggregated to a Cd5(beta C-->N)2 dimer, which exhibited unusual structure as observed by its 113Cd-nuclear magnetic resonance. These differences in structure and reactivity demonstrated that the requirements for formation of a stable Cd3S9 beta-cluster are more stringent than simply the sequential positions of the cysteines along the peptide chain and must include interactions involving neighboring, noncysteine amino acids.

Amino Acid Sequence↗