Search PubMed⌕ Search

Biomedical subjects

P Puig

Publications and source records attributed to P Puig.

25 records · Page 2Linked to original sources
PubMedDate not supplied

[Negative binomial distribution versus Poisson in the analysis of recurrent phenomena].

OBJECTIVE: The aim is to unfold the difficulties likely to arise in risk calculations through aggregated database when the studied phenomenon is recurrent and to display the negative binomial distribution as a valid and simple alternative to analyse this kind of phenomenon. METHODS: When the studied phenomenon is recurrent, the analysis by means of the Poisson regression can provoke overdispersion or extra-poisson variance, what leads to underestimating the standard errors in coefficients and may divert into the statistical significance of factors which as a matter of fact are not associated with the phenomenon beforehand. The negative binomial can grasp part of the variance which the Poisson is unable to identify. In order to check this out, the fit of both distributions were compared, based on the number of hospitalizations of individuals aged between 65 and 69, during 1996. This comparison was carried out by means of two different aggregated databases: by individuals and by variables. RESULTS: There were differences in the fitted models by means of both distributions in both databases. By the analysis of the residuals, when using the base by individuals, the negative binomial fits correctly 67.9% of the observations badly fitted by the Poisson. Using the aggregated variables database, the percentage is 50%. In both cases, Poisson estimates four out of the six studied variables as significant. As to the negative binomial, there are two significant based on individuals and one in the variable database. CONCLUSION: The existence of overdispersion is frequent in recurrent-type phenomena. When this occurs, the negative binomial distribution is more appropiate than the Poisson.

Aged↗
PubMedDate not supplied

Comparative F statistics analysis of the genetic structure of ten Spanish dog breeds.

The genetic structure and relationships among 10 Spanish dog breeds have been studied by using F statistics. Data came from 21 structural genic loci that codify for blood-soluble proteins and enzymes detected by electrophoresis. Of the 21 loci, 11 were found to be polymorphic. The study was done at three levels of hierarchical differentiation: ancestral trunks, breeds, and subpopulations. The deficit of heterozygotes was estimated at the subpopulation, breed, and ancestral trunk levels, with values of 4.0%, 6.5%, and 11.2%, respectively. In the whole population, the deficit of heterozygotes was about 17%. The proportion of genetic variability attributable to differences between subpopulations, breeds, and ancestral trunks was estimated to be 14.2%, 9.9%, and 6.9%, respectively. The dendrogram, obtained by using values of genic differentiation (FST) as a measure of the genetic distance among populations, is topologically identical to the one obtained using Nei's index of distance, which indicates a high correlation (r = .99) between both distances. These racial groupings, however, differ from the grouping obtained from historical, archeological, and morphological data.

Animals↗
PubMedDate not supplied

Hub colonization as the initial step in an outbreak of catheter-related sepsis due to coagulase negative staphylococci during parenteral nutrition.

A prospective study was carried out to determine the pathogenesis of coagulase negative staphylococci catheter-related sepsis during parenteral nutrition. Forty-three catheters were cultured by semiquantitative and quantitative methods. The skin around the puncture site was cultured at the time of catheter removal and three segments of the catheter were cultured apart: the hub, the proximal subcutaneous segment, and the tip. Skin cultures were negative (89%) or yielded different coagulase negative staphylococci from those recovered in catheter and/or blood. Seventeen catheters were the source of sepsis. In 15 cases an infected hub was associated with an infected tip. In two cases the hub was negative (one sepsis due to mixture contamination and the other due to hematogenous seeding of the catheter tip). Sixteen cases of sepsis were due to coagulase negative staphylococci. Staphylococcus epidermidis has been the species most commonly isolated, followed by Staphylococcus haemolyticus, Staphylococcus saprophyticus, and Staphylococcus hominis. In our patients most catheter sepsis have their origin in an infected hub and are not due to migration of skin bacteria along catheter subcutaneous tunnel.

Cross Infection↗
PubMedDate not supplied

Postoperative hypocaloric parenteral nutrition. A study in patients without neoplasm.

Hypocaloric peripheral parenteral nutrition during the postoperative period aims to reduce or minimize protein loss and avoid use of central venous catheters. The efficacy of such nutrition in regard to postoperative outcome and nitrogen balance was evaluated in comparison with standard fluid therapy. The study was performed on 49 well-nourished patients who underwent major surgery for non-neoplastic conditions. Group I received 1 g amino acids + 1 g xylitol and 1 g sorbitol/kg body weight, while standard fluid therapy was given in group II. No significant intergroup difference was found in serum levels of albumin, total protein, prealbumin, transferrin or retinol-binding protein. The blood urea, nitrogen excretion and nitrogen balance were significantly higher in group I. The postoperative outcome was similar in both groups, as were the observed complications. Thus although the nitrogen balance was superior in group I, no intergroup difference was clinically evident.

Abdomen↗