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Biomedical subjects

J Olmos

Publications and source records attributed to J Olmos.

15 recordsLinked to original sources
PubMed2004

Genetic characterisation of Helicobacter pylori isolates from an Argentinean adult population based on cag pathogenicity island right-end motifs, lspA-glmM polymorphism and iceA and vacA genotypes.

Isolates of Helicobacter pylori from 88 patients were characterised by cagA status, cagA pathogenicity island (PAI) right-end motifs, iceA, vacA and lspA-glmM genotypes, primarily by PCR-based analysis, to investigate whether Argentinean isolates differed from those recovered in southern Europe or other Latin American countries. PCR-based analysis of vacA alleles was confirmed by reverse hybridisation in 56 cases, while sequence analysis was performed either when iceA and vacA genotypes could not be determined by PCR, or to investigate PCR and reverse hybridisation vacA genotyping discordance. Typing by lspA-glmM restriction fragment length polymorphism was performed with HhaI and AluI. The pattern of cag PAI right-end motifs and the prevalence of type Ia were similar to those in isolates from southern European countries, with cagA(+)/iceA1/vacA-s1 m1 being the commonest genotype. Reverse hybridisation identified a vacA-s1a/s1b recombinant allele, confirmed by sequencing analysis. Analysis of lspA-glmM genotypes identified at least 73 unrelated strains. Few mixed infections were identified, but in one case, isolates from a single biopsy exhibiting two vacA alleles were shown by lspA-glmM fingerprints to be two unrelated strains. No associated effect on ulcer disease risk was demonstrated by analysis of cagA, vacA and iceA status. Overall, the isolates of H. pylori from Argentina were similar to isolates from southern Europe or Latin American countries, and infections were associated mainly with single H. pylori strains.

Adult↗
PubMed2003

Molecular identification of pathogenic and nonpathogenic strains of Vibrio harveyi using PCR and RAPD.

Fifteen environmental samples of Vibrio spp. isolated from healthy and diseased shrimps were tested for pathogenicity to juvenile shrimps. Two isolates, strains Z2 and Z3, were observed to be pathogenic, causing 100% mortality of the target host compared to the control strain Vibrio harveyi ATCC 14126. Environmental and type strains were subjected to molecular characterization by restriction fragment length polymorphism (RFLP) and PCR using primers targeted to different virulence, transcriptional regulator, or quorum sensing genes from V. harveyi. Primers designed for luxN were specific and identified all the environmental strains as V. harveyi. The random amplified polymorphic DNA (RAPD) method was used to differentiate between pathogenic and nonpathogenic strains of V. harveyi. These methodologies allowed us to detect and distinguish strains virulent and avirulent to juvenile shrimp.

Animal Diseases↗
PubMed2000

Molecular identification of Dunaliella sp. utilizing the 18S rDNA gene.

The utilization of micro-algae for the production of food and fine chemicals is growing in importance. However, confusion of names and species makes comparison of results by different authors very difficult. In this work, five species of Dunaliella were characterized using their 18S ribosomal RNA genes. Conserved oligonucleotides complementary to 5' and 3' termini of the 18S rDNAs were designed and utilized to amplify theme, restriction fragment length polymorphism analysis of the polymerase chain reaction products was developed. Species-specific primers were also designed and utilized to corroborate the identification.

DNA Primers↗
PubMed1997

Effects of the sinR and degU32 (Hy) mutations on the regulation of the aprE gene in Bacillus subtilis.

The aprE gene of Bacillus subtilis codes for the serine alkaline protease known as subtilisin. Its expression is regulated by a complex network of activators and repressors that includes the products of hpr, degU and sinR. In order to understand the effect of these gene products on subtilisin expression, strains carrying combinations of the degU32(Hy), hpr2 and sinR null mutations, were constructed. We found that in all the genetic backgrounds tested, the sinR null mutation decreased aprE expression. Also, by measuring alkaline phosphatase synthesis and the formation of heat-resistant spores, as indicators of sporulation, we found that some of the mutant strains showed alterations in the sporulation process. These results suggest that these alterations are partially responsible for some of the observed changes in aprE expression.

Bacillus subtilis↗
PubMed1996

A functional Spo0A is required for maximal aprE expression in Bacillus subtilis.

The initiation of sporulation in Bacillus subtilis is under control of the transcriptional factor Spo0A. Most Spo0A mutants fail to initiate the sporulation process and all the sporulation initiated processes such as the synthesis of subtilisin. However, the product of spo0A9V, one of the several spo0A mutants characterized, distinguishes itself in the fact that, while it appears to effectively repress abrB, it fails to activate the spoIIA operon. The aim of this study was to examine the effect of the spo0A9V mutation on aprE expression and we found that in different genetic backgrounds, the spo0A9V mutation has a negative effect on aprE::lacZ expression.

Bacillus subtilis↗
PubMed1995

[Multicenter study for the evaluation of the reproducibility in the measurement of rectal sensorial threshold].

A simple way to evaluate the rectal sensorial threshold has been the sloped distention of a rectal balloon, as a way to obtain the required volume to induce desire to defecate (VDE) and pain (VTM). Six medical groups belonging to the Argentine Motility Circle, studied in 14 patients (7M, 7F age 51 +/- 10.1) the VDE and VTM. The measurements were repeated in the same subjects with intervals longer than 24 Hs. The estimate of precision established a coefficient of variation (CV) for VDE of 10.23% (2CV = 20.46%). And so Reproducibility was found to be not acceptable. The CV for VMT was 1.44 (2CV = 2.88%) this could be considered a very good reproducibility. In conclusion, the VTM appears to be a reproducible measurement suitable for clinical and pharmacological studies of the rectal sensorial perception.

Adult↗
PubMed1994

Production in Escherichia coli of a rat chimeric proinsulin polypeptide carrying human A and B chains and its preparative chromatography.

A pseudohuman proinsulin coding DNA sequence (MMRPI) carrying human A and B chains, was constructed via directed mutagenesis of a previously modified rat proinsulin cDNA (MRPI) and expressed as a tryptophan (Trp)LE-proinsulin fusion protein in Escherichia coli W3110. Expression of the hybrid gene was achieved by depletion of tryptophan from the medium. The heterologous fusion protein, accumulated as insoluble inclusion bodies within the cell, was obtained by differential centrifugation and then solubilized using formic acid. At the junction of the two peptides, a methionine residue allowed proinsulin to be released from the carrier protein by cyanogen bromide treatment. The sulfonated form of this proinsulin polypeptide was easily purified, at a preparative level, using ion exchange chromatography.

Amino Acid Sequence↗
PubMed1994

Effectiveness of two different methods for preparing curved root canals.

In this study, the effect of using two different methods for preparing curved root canals of extracted, single-rooted teeth were analyzed with the scanning electron microscope. The instrumentation systems tested were the Canal Master and a standard circumferential filing technique in which conventional K-files were used. Shaping effectiveness was qualitatively evaluated in terms of respect for conservation of the apical constriction and the presence or absence of ledging, specially in the apical third of the root canals. As a result of our observations, it appeared that the Canal Master instrumentation technique provided well-centered and tapered preparations. Conversely, the use of conventional K-files with a standard circumferential filing technique resulted in frequent alterations of the initial pattern of the root canals, showing transportation of the apical foramen and ledge formation.

Dental Pulp Cavity↗
PubMed1994

[Do the physical characteristics of radiopaque markers modify the results of the measurement of colonic transit time?].

UNLABELLED: This study was performed in 15 healthy control subjects (8 males- age 23-70 and 7 females age 20-74) as a way to compare the total and segmental colonic transit time with two different type of radiopaque markers. One type of markers was 3 mm cut sections of a radiopaque polietilene 14 French Levine tube, with a medium weight of 64.3 mg and a specific gravity (SG) of 1.28. The other type were 7 mm lenticular insoluble barium (lentils) with medium weight of 231 mg and a SG of 1.87. Each subject ingested 20 markers of each type with the breakfast and front and profile plain films of the abdomen were taken 24 and 48 hs after. The total colonic transit time for the polietilene markers was 17.7 hs and 27.3 hs for the barium type (BM) (p < 0.001). The segmental transit time for right colon was 2.4 hs (PM) and 9.7 hs (PM) and 9.7 hs (BM) (p < 0.001) in the left colon 9.5 hs (PM) and 11.3 hs (BM) and in rectoanun 5.9 hs (BM) with no statistical significance. CONCLUSION: the physical characteristics of the radiopaque markers can modify the results of the colonic transit times.

Adult↗
PubMed1994

A new method to assess gastric mucosa rewarming time in patients with portal hypertension.

It is possible that the mucosal damage in congestive gastropathy of portal hypertensive patients may have an ischemic basis, since rewarming time in other sites correlates with local blood flow, a method was designed to assess the capacity of the gastric mucosa to rewarm the stomach after a cold challenge, as an index of ischemia. Eleven control subjects and 15 patients with portal hypertension (10 treated with sclerotherapy) were studied with an integrated circuit temperature transducer connected to a digital display. A balloon containing the temperature transducer inside was reversibly fixed 10 cm. proximally to the distal end of a panendoscope. Once upper endoscopy was completed, the balloon placed in the antrum was infused with cooled water (2 degrees C) through a polyethylene tube. The time elapsed for the water to be rewarmed from 20 degrees C to 25 degrees C to 30 degrees C and 20 degrees C to 30 degrees C was measured. Reproducibility of repeated measurements, gave a coefficient of variation of 6%. Total rewarming time was (-mean +/- SD) 178 +/- 51.3 seconds, significantly higher in Portal hypertensive patients as compared to 114 +/- 34.7 seconds in Controls (P < 0.001). (95% Confidence Interval: -X = 63.4 seconds Cl 45.02 to 81.78). 60% of Sensitivity and 100% of Specificity The slower rewarming time in patients with portal hypertension may be the result of mucosal ischaemia, but oedema and cellular infiltration could also affect the heat flow.

Adolescent↗
PubMed1993

[pH-metric variables in gastroesophageal reflux in asthmatic patients].

As there is an increased incidence of gastroesophageal reflux (GER) in asthmatic patients compared with the normal population, in the present trial we have tried to establish the following: 1) Possible differences in pH-metric variables between patients with GER and asthma, and asthmatic patients with or without GER 2) The usefulness of simultaneous evaluation and correlation of reflux episodes with the respiratory peak flow (EPF) in asthmatic patients. 31 patients divided in four groups were compared. A) 16 patients with typical symptoms of GER without respiratory symptoms. B) 10 asthmatic patients with GER symptoms. C) 5 asthmatic patients without GER symptoms. D) 15 asthmatic patients who represents the sum of B and C. In all patients ambulatory computerized, four hours pH recordings were obtained after standard meal. The study was divided in two equal periods (upright and recumbent). The EPF was measured before starting the study and every 20 min during the recumbent period. From de following pH-metrics variables: total number of reflux episodes, percentage of recording time when intra-oesophageal pH < 4 in the upright position or recumbent position and for the total period, duration of longest reflux episode, number of episodes longer than five minutes, and correlation between reflux episodes and patients symptoms. Only differences were seen when the time of the longer period with GER and the number of patients with more than five minutes episodes were compared between groups A and D. From the results we conclude that the GER in asthmatic patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Asthma↗
PubMed1992

[Manometric effects of pinaverium bromide in irritable bowel syndrome].

The effects of pinaverium bromide on colonic motility were investigated in a controlled, controlled, cross-over study in 32 patients with irritable bowel syndrome. Constipation was clearly predominant in one group of 16 patients, and diarrhea in the other group of 16. Manometric measurements were taken of the colonic motor response generated by distention of a balloon inserted to the rectosigmoid junction. Measurements were taken before and one hour after ingestion of two tablets containing placebo or two tablets each containing 50 mg of pinaverium bromide. Following intake of placebo the motility index increased from the basal value in patients with constipation, and resistance to distention decreased in the diarrhea group. These changes were attributable to repetition of the mechanical stimulus within a relatively brief time lapse, or more probably to the ingestion of liquid which accompanied intake of tablets. Compared with placebo, pinaverium bromide induced inhibition of both effects. From the therapeutic point of view, the decrease in motility index seen in patients with irritable bowel syndrome and constipation is particularly interesting.

Adult↗