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Biomedical subjects

P Coll

Publications and source records attributed to P Coll.

119 records · Page 7Linked to original sources
PubMed1985

Aspects relating to the calculation of doses in moving radiation fields.

This article summarizes the results obtained from several studies conducted by the author, concerning the calculation of doses received at moving radiation fields generated by photon-emitting radiation sources. An attempt is made to provide a methodology for the aforementioned calculation, in those cases where simple geometries are involved, using what is described as the "duality principle" and the concept known as "equivalent static system" (EES), so as to be able to draw upon the wealth of data available in reference material relating to static systems.

Methods↗
PubMed1985

Homocystinuria and schizophrenia. Literature review and case report.

The autosomal recessive disorder homocystinuria involves, in all its subgroups, an abnormality of methionine metabolism. The metabolism of methionine has been a central focus of interest for those who propose the transmethylation hypothesis of schizophrenia. The "methionine effect," as described in the research literature, is thus a theoretical link between these two disorders. The authors review the literature and describe those cases where both have occurred in the same patient. They indicate that whereas many patients with homocystinuria have been psychotic, few have been actually labeled schizophrenic. A patient with homocystinuria, mental retardation, and episodic psychosis is described and this case is used to point to the difficulties in making a definite psychiatric diagnosis in these patients. A relationship between the two syndromes is suggested.

Adult↗
PubMedDate not supplied

Microbiological quality control study of "all-in-one" total parenteral nutrition admixtures.

A microbiological quality control study of parenteral nutrition (PN) is presented. The study was carried out in the Pharmacy and Microbiology Services of the Hospital de la Santa Creu i Sant Pau (Barcelona, Spain) from April 1991 to May 1998 and represents more than 25,000 lipid-containing PN admixtures prepared during that 7-year period. A randomized sampling procedure according to the cumulative sum control charts was performed and a 0.45-microm membrane filtration method was used as the microbiological test. Validation showed that the method is sensitive for sterility tests. Bacterial growth was observed on 59 filters (4.58% of the samples). A second control was made for these positive outcomes, and bacterial growth was found in only two cases. The patients' clinical history was reviewed and no relation between the microorganisms of the nutrition and the results obtained from blood cultures was observed. The quality control study revealed a low incidence of contamination in our PN preparation process.

Bacteria↗
PubMedDate not supplied

[An outbreak of gram-negative bacteremia (GNB), especially enterobacter cloacae, in patients with long-term tunnelled haemodialysis catheters].

Vascular access through a venous catheter for haemodialysis is associated with increased risk of thrombosis, central venous stenosis, short access survival and inadequate dialysis. The most important catheter-related complications, which determine method survival, are infection and dysfunction. In particular, infectious episodes are in some studies the leading cause for untimely catheter removal and for catheter-related morbidity but also for morbidity in dialysis patients. Double-lumen central venous catheters used for haemodialysis, are common causes of septicaemia. Most cases are caused by staphylococci. Episodes of gram-negative bacteriemia have been traced to bacterial contamination of water and/or dialysate, errors in dialyzer reprocessing, and improper setup procedures. In this paper, we describe and outbreak of gram-negative bacteremia, firstly E. cloacae, in an outpatients haemodialysis unit, in the patients with long-term tunnelled haemodialysis catheters. We describe the epidemic investigation that we achieved to identify the source of contaminating bacteria and the route by which bacteria gained access to the bloodstream. We prove the contamination by gram-negative bacterium of the water-distribution lines and haemodialysis machines. Moreover, E. cloacae strains isolated from the lines and machines are genotypically identical to the isolated from the patients. Also, we prove that the hands of health care personnel are unintentional carriers. The outbreak was finished when decontamination of dialysis machines was enhanced and dialyzer-priming fluid was modified.

Aged↗
PubMedDate not supplied

[IS6110 for typing strains of Mycobacterium tuberculosis: application of a standardized protocol with computerized image analysis].

BACKGROUND: For the epidemiological control of tuberculosis it is necessary to use specific markers for strain differentiation. The analysis of the restriction fragment length polymorphism (RFLP) by using the insertion sequence IS6110 as a probe, allows us to establish accurately the strains which are around in a population. Our study evaluates the efficiency of this marker in 136 strains of Mycobacterium tuberculosis isolated from our surroundings. A standardized protocol is used, and a computerized system to analyze the images is described. METHODS: DNA restriction was done with PvuII. The filters were revealed by following a chemiluminescence method using a 867 bp probe, which is located to the right of the PvuII site IS6110. The comparison of the patterns obtained was done in a computer. The coefficient of Dice was calculated to express the similarity of the profiles given by two strains. The strains were clustered by the UPGMA method. The graphic representation of the clusters was done by means of homology dendrograms. RESULTS: 124 different patterns were obtained from which 118 strains had a unique pattern while 18 shared it. The index of discrimination was 0.996. Ninety two percent of the strains had more than 6 bands and none had no IS6110. The median of homology was 27% in 8 of the patients, 2 consecutive isolates were studied with the result of no variation seen on the patterns. CONCLUSION: IS6110 has shown very effective because of its stability and high discriminative power. The standardized protocol together with a computerized analysis of the images obtained allows comparison of results, furthermore, to establish centralized data base. This would be very useful for epidemiological studies of tuberculosis and the chase of strains with special characteristics.

Bacterial Typing Techniques↗
PubMedDate not supplied

[Etiology of enteritis in a university general hospital in Barcelona (1992-1995)].

BACKGROUND: The aim of the study was to describe the etiology of enteropathogenic agents over a four-year period (1992-1995) in a University Hospital in Barcelona. METHODS: We studied 12,793 stool samples, 4519 were obtained from patients under 15 years and 8274 were obtained from patients over 14 years. The specimens were examined for bacteriological, parasitological and virological enteropathogens. RESULTS: In 3380 specimens of 12,793 stool samples studied were identified an enteropathogen (26.4%). Polymicrobial associations were observed in the 6.8% of the cases. Pathogens were identified in 45% of children samples and 16.3% of adults samples. The etiological enteritis agents more frequently detected in the paediatric patients were Campylobacter (13.5%), rotavirus (11.3%) and Salmonella (10.2%); and Salmonella (4.9%), Campylobacter (3.1%) and Giardia intestinalis (2.1%) in adults. Cryptosporidium (13.5%) was the most frequent cause of gastrointestinal tract infections in HIV-infected subjects. In the children with stools positives, the presence of red and white blood cells were more frequent than the adults with stools positives (73% versus 26.6%). CONCLUSIONS: The enteropathogenic agents such as Campylobacter, Salmonella, and Giardia were the most frequent cause of gastroenteritis in our environment. In the children, rotavirus infections predominated during the cold months. The most frequent cause of gastroenteritis in HIV-infected patients was Cryptosporidium followed by Campylobacter.

Adolescent↗