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Biomedical subjects

M Vicente

Publications and source records attributed to M Vicente.

87 records · Page 5Linked to original sources
PubMed1973

Glucolysis in Pseudomonas putida: physiological role of alternative routes from the analysis of defective mutants.

A number of mutants in which glucolysis is impaired have been isolated from Pseudomonas putida. The study of their behavior shows that this organism possesses a single glucolytic pathway with physiological significance. The first step of the pathway consists in the oxidation of glucose into gluconate. Two proteins with glucose dehydrogenase activity appear to exist in P. putida but the reasons for this duplicity are not clear. The process continues with the formation of 2-ketogluconate which is in turn converted into gluconate-6-phosphate. This is proved by the fact that mutants unable to form gluconate-6-phosphate from 2-ketogluconate show extremely slow growth on glucose or gluconate (generation times are increased more than 100 times). Other possible routes for the conversion of glucose into gluconate-6-phosphate, the glucose-6-phosphate pathway, or the direct phosphorylation of the gluconate formed by glucose oxidation are only minor shunts in P. putida. The Entner-Doudoroff enzymes, which catalyze the conversion of gluconate-6-phosphate into pyruvate and triosephosphate, appear to be essential to grow on glucose and also on gluconate and 2-ketogluconate. A significative role of the pentose route in the catabolism of these substrates is not apparent from this study. In contrast, P. putida strains showing no activity of the Entner-Doudoroff enzymes grow readily on fructose, although there is evidence that this hexose is at least partially catabolized via gluconate-6-phosphate.

Culture Media↗
PubMed1973

Antibodies against human types A and B influenzaviruses in the sera of animals in Spain.

Sera from several animal species were subjected to serological tests for antibodies against types A and B influenzaviruses of human origin. Of the swine sera, 13% were positive by the haemagglutination-inhibition test for the human A strain and, of those, 68% were also positive by the neuraminidase-inhibition test. None of the sera tested was positive for the B strain.

Animal Population Groups↗
PubMedDate not supplied

On the chronology and topography of bacterial cell division.

Gene products that play a role in the formation of cell septum should be expected to be endowed with a set of specific properties. In principle, septal proteins should be located at the cell envelope. The expression of division genes should ensure the synthesis of septal proteins at levels commensurate with the needs of cell division at different rates of cell duplication. We have results indicating that some fts genes located within the 2.5-min cluster in the Escherichia coli chromosome conform to these predictions.

Bacterial Proteins↗
PubMedDate not supplied

[Smoking prevention in the school: results of a 3-year program].

Tobacco use poses one of the greatest health problems at school. Its prevention through health education should be assumed up by all members of the school community and health personnel (especially family and respiratory physicians). We designed an anti-tobacco program lasting three years aimed at all the students of the 6th, 7th and 8th grades at school as well as those in the pre-university years that was implemented in a rural area. This study reports the results of the attitudes of the 610 students (256 boys and 354 girls, between 11 and 20 years old) collected at the end of the program. 59.4% of the boys and 44.1% of the girls reported having smoked on some occasion. The mean age at the time of the first contact with tobacco was 11.8 +/- 2.4 years, this being significantly different between the boys and the girls. The main reasons for starting to smoke tobacco were quoted as peer pressure (57.1%) and curiosity (55.5%). That their parents smoked was only adduced as a reason by 29.5% of the students. Knowledge of the harmful effects of tobacco was limited and only 57% related tobacco smoking to lung cancer and only 41% to coronary pathology. At the end of the program 13.6% of the students involved smoked. 93.9% of those who quit smoking related this event to the program. Of those still smoking, 63.6% said they would like to quit. This justifies the need to reinforce the knowledge that will allow them to switch attitudes and stop smoking. Intervention programs in school populations have proved to be useful in the struggle to decrease smoking among school children. If an adolescent can avoid smoking it is likely that s/he will not smoke in adulthood. It is necessary to further develop this type of anti-tobacco program as reflected in this paper.

Adolescent↗
PubMedDate not supplied

[Etiology of lower respiratory infections in hospitalized infants].

As a contribution to knowledge about the etiology of lower respiratory tract infections (LRI) in infants, 235 patients aged one year or less admitted to a children's hospital at northern metropolitan area of Santiago, Chile along years 1987 throughout 1989 with radiologically confirmed diagnosis were studied. Infants were eligible only if their symptoms lasted for not more than five days and their hospital stay was less than two days. Controls consisted on 74 healthy infants. A search for presumptive etiology was done by means of usual bacteriological procedures (pharyngeal swabs and blood cultures), plus latex test for type b Haemophilus influenzae (Hib) and Streptococcus pneumoniae (SP) in concentrated urine specimens; indirect immunofluorescence (IF) for specific Chlamydia trachomatis (CT) IgM; serological tests, isolation and IF in pharyngeal aspirates for syncytial respiratory virus (SRV), influenza, parainfluenzae and adenoviruses were also used. Evidence of viral infection was detected from 135/235 (57.5%) of cases and 21/74 (28.3%) controls, SRV being the most common. From 18/119 and 2/119 studied patients Hib and SP antigens were respectively detected, but urinary antigens were also present in 6/24 controls, raising questions about this test's specificity. IF titers of 1:32 or higher for CT were found in 5/80 patients, all younger than 5 months. It was possible to perform the whole set of available methods in 80 patients, in 70% of which some evidence of a known etiologic agent was found. Serology alone gave etiological clues in only 30% of these cases and usual microbiological cultures of throat swabs and blood from none of them. No combinations of age, fever, respiratory rate, apnea, bronchial obstructive syndrome, white blood cell counts over 15,000 or of band forms over 500 per cu mm, erythrocyte sedimentation rates, reactive C protein and x-ray findings allowed differential diagnosis between presumptive bacterial or viral etiology, except in one case of an infant presenting with pleural effusion and positive antigenuria for Hib.

Bronchopneumonia↗
PubMedDate not supplied

[Hospital acute respiratory infections].

To study the incidence of nosocomial respiratory tract infection along the first week after admission, 31 children under 2 years of age admitted to the pediatric wards of a general hospital at Metropolitan Santiago, Chile, with the diagnosis of lower respiratory tract infection, were studied for viral agents by immunofluorescence tests, viral isolation from pharyngeal aspirates, paired serum viral antibodies and bacterial cultures, all of them performed at admission and 4 to 5 days later from May through August 1988. In 13 out of 31 patients admitted because of acute lower respiratory tract infection at least one new virus (to a total of 18 viral isolates) was detected in the second sample, which could have been nosocomially acquired, as follows: adenovirus from 8 cases, respiratory syncytial virus from 5 patients and cytomegalovirus from 5 patients, in different combinations. No significant changes in bacterial cultures were found.

Acute Disease↗
PubMedDate not supplied

[Bronchiolitis].

Explore the source record for details and available documents.

Age Factors↗