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G Perdomo

Publications and source records attributed to G Perdomo.

7 recordsLinked to original sources
PubMed2004

[Action-oriented participant research as a strategy for training and evaluation in health education].

In this article we present the results of a study on educational practices at the "Escuela de Malariología y Saneamiento Ambiental 'Dr. Arnoldo Gabaldón'" (EMSA), a pioneering institution in training health personnel, pertaining to the Ministry of Health and Social Assistance in Venezuela. This study was developed as an experiment in action-oriented participant research, i. e. authorities, teachers, and students were committed to an evaluation of the educational practices in which they were involved. The main results of this cooperative inquiry were: a theoretical reconstruction of the models of health education employed by EMSA; a critical analysis of those models; and the design and testing of an alternative model centered on community participation.

English Abstract↗
PubMed2001

Evidence for multiple nitrate uptake systems in the yeast Hansenula polymorpha.

Hansenula polymorpha mutants disrupted in the high-affinity nitrate transporter gene (YNT1) are still able to grow in nitrate. To detect the nitrate transporter(s) responsible for this growth a strain containing disruption of the nitrate assimilation gene cluster and expressing nitrate reductase gene (YNR1) under the control of H. polymorpha MOX1 (methanol oxidase) promoter was used (FM31 strain). In this strain nitrate taken up is transformed into nitrite by nitrate reductase and excreted to the medium where it is easily detected. Nitrate uptake which is neither induced by nitrate nor repressed by reduced nitrogen sources was detected in the FM31 strain. Likewise, nitrate uptake detected in the strain FM31 is independent of both Ynt1p and Yna1p and is not affected by ammonium, glutamine or chlorate. The inhibition of nitrite extrusion by extracellular nitrite suggests that the nitrate uptake system shown in the FM31 strain could also be involved in nitrite uptake.

Anion Transport Proteins↗
PubMed2000

Cloning, sequencing, and expression of H.a.YNR1 and H.a.YNI1, encoding nitrate and nitrite reductases in the yeast Hansenula anomala.

A single Hansenula anomala genomic DNA fragment containing the genes H.a.YNR1 (yeast nitrate reductase) and H.a.YNI1 (yeast nitrite reductase) encoding nitrate and nitrite reductase, respectively, was isolated from a lambda EMBL3 genomic DNA library. As probe, a 3.2 kb DNA fragment isolated from a lambda gt11 H. anomala genomic DNA library screened with antiserum anti-NR from H. anomala was used. H. a.YNR1 and H.a.YNI1 genes are separated by 473 bp and encode putative proteins of 870 and 1077 amino acids, respectively, with great similarity to nitrate and nitrite reductases from other organisms. Northern blot analysis revealed that both genes are highly expressed in nitrate, very low in nitrate plus ammonium, and no expression was detected in ammonium or nitrogen-free media. Levels of nitrate reductase and nitrite reductase were very low or undetectable by Western blot analysis in nitrogen-free and ammonium media, whereas both proteins were present in nitrate and ammonium plus nitrate media. The nucleotide sequence Accession No. is AF123281.

Amino Acid Sequence↗
PubMed1999

One-step, PCR-mediated, gene disruption in the yeast Hansenula polymorpha.

Previous evidence based on the experience of our laboratory showed that one-step gene disruption in the yeast Hansenula polymorpha is not straightforward. A systematic study of several factors which could affect gene disruption frequency was carried out. We found that the more critical factor affecting one-step gene disruption in H. polymorpha is the length of the target gene region flanking the marker gene. Target gene regions of about 1 kb flanking the marker gene were necessary to obtain a disruption frequency of about 50%. However, the gene marker, either homologous or heterologous, the locus and the strain examined did not significantly affect the frequency of disruption; the highest disruption frequency obtained for the YNR1 gene was in the strain HMI39, using the Saccharomyces cerevisiae URA3 gene as a marker. Since long regions flanking the gene marker do not allow the easy PCR-mediated strategies, developed for S. cerevisiae, to obtain constructs to disrupt a given gene in H. polymorpha, an alternative PCR strategy was developed.

Blotting, Southern↗
PubMedDate not supplied

[Quality of the reagents used in counterimmunoelectrophoresis technique for the determination of antirabies antibodies].

This study demonstrated that the antigens and indicator sera produced by the Butantan Institute may be employed with success in the counterimmunoelectrophoresis technique for the titration of rabies antibodies in sera from immunized individuals. No statistically significant differences were demonstrated between the results obtained in the standardization tests carried out at the Butantan Institute and the reference control tests performed at the Pan American Zoonoses Center. It is proposed that the Butantan Institute be in charge of the production and distribution of these reagents at the national level.

Animals↗
PubMedDate not supplied

[Hepatic abscess in children: analysis of 20 cases].

Between March 1986 and March 1989, 20 children were diagnosed as having liver abscesses at the Pediatric Department of the Central Hospital in Valencia. 10 were amebic and 10 pyogenic abscesses. 85% occurred in children and 15% in infants. 15 of them (75%) were located in the right lobe, 80% of amebic abscesses had positive serological tests. An etiologic agent was found in 50% of the pyogenic abscesses (3: E. coli, 2: S. Aureus). 80 to 90% of patients presented abnormal prothrombin time. Sedimentation rate was very high in both groups, even at the discharge time. Hepatomegaly, fever, anemia and abdominal pain were the main clinical features. The macroscopic aspect of the aspirate was not helpful in the diagnosis. 60% of amebic liver abscesses needed only medical treatment but 80% of pyogenic abscesses deserved medical treatment and needle aspiration.

Child, Preschool↗