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Biomedical subjects

A Otero

Publications and source records attributed to A Otero.

At least 109 records · Page 6Linked to original sources
PubMed1993

Prominent expression of the actin-sequestering peptide Fx gene in the hippocampal region of rat brain.

We have analyzed by in situ hybridization the distribution of Fx (an actin-sequestering peptide) mRNA in the brain of young and old rats. The strongest Fx mRNA-specific hybridization signal was located in the hippocampo-entorhinal cortex; this mRNA was also found in the piriform cortex, amygdala, lateral septum and neocortex. Northern blot analysis confirmed the prominent expression of the Fx transcript in the hippocampus and showed a notably lower amount of this mRNA in the hippocampus of old rats suggesting an influence of aging on the expression of this gene. The possible implication of Fx in synaptic plasticity and in long-term potentiation is discussed.

Aging↗
PubMed1993

Transcript levels of thymosin beta 4, an actin-sequestering peptide, in cell proliferation.

Thymosin beta 4 (beta 4) is an ubiquitous 5-kDa peptide that has been identified as an actin-sequestering peptide. In this work, Northern blot analysis was used to study the beta 4 mRNA levels during the cell cycle of rat thymocytes and hepatocytes as well as in human lymphocytes from patients with leukemia. beta 4 mRNA was found in all the stages of thymocyte and hepatocyte cell cycle, showing an increase in the S-phase which was maintained during the G2 and M phases. Incubation of splenic T-cells with concanavalin A, phorbol myristate acetate or the ionophore A23187 lead to a similar increase of beta 4 transcript during the S-phase. The increase in beta 4 mRNA observed in the G2/M boundary of the cell cycle, together with its ability to inhibit actin polymerization, suggests a possible role of beta 4 in the the morphological changes and actin redistribution occurring during the cytokinesis.

Actins↗
PubMed1993

Modern microbiological methods for foods: colony count and direct count methods. A review.

Over the last years methods for enumeration of microorganisms in foods are changing rapidly. Techniques based on totally new concepts as well as instruments and miniaturized systems that allow the automation and simplification of existing microbiological procedures have been developed. These rapid methodologies should satisfy the increasing requirements for effective quality assurance of foods. In the present paper we review some of the more interesting methods based on colony count or direct bacterial count.

Animals↗
PubMed1993

[Incidence, behavior and control of Aeromonas hydrophila in meat and dairy products].

This review deals with several aspects of Aeromonas hydrophila and other motile Aeromonas species associated with foodborne illness. Although it is mainly dedicated to the factors affecting growth and survival of this species in foods of animal origin, information on other topics is also provided. This paper includes sections on: Taxonomy, diseases caused by Aeromonas, virulence factors, reservoirs and prevalence in foods and water, factors affecting growth and survival, isolation and identification, and control measures.

Aeromonas↗
PubMed1993

Factors affecting spoilage microflora succession on lamb carcasses at refrigeration temperatures.

Three bacterial groups were detected during the shelf-life of lamb carcasses stored at refrigeration temperatures: coryneforms (mostly Brochothrix thermosphacta), Gram-positive cocci (staphylococci) and Gram-negative bacilli (Pseudomonas spp. and Moraxella spp.). Influence of categorical variables such as sampling day, sampling area and sampling method on their recovery was analysed by a chi-square test of independence and loglinear analysis. Hierarchical loglinear modelling proved to be very useful as several three-way interactions of factors were observed.

Actinomycetales↗
PubMed1992

[New trends in medical education. Evaluation of placements in health centers].

Whether to use just hospitals or a wider range of health resources is one of the debating-points in the updating of undergraduate medical training programmes. The Faculty of Medicine in the Autonomous University of Madrid integrated obligatory Primary Care placements for students in the last year of their course, into its syllabus as from 1988/89. This programme and the students' own assessment of it was studied by means of a systematic, voluntary and anonymous survey, which covered various aspects of their assignments to Primary Care teams. 93% (473) replied. Every student took part in the clinical activities, both on demand and as programmed. 76% went on home visits along with their tutors. 88% considered that their placement was active. The overall evaluation of the placement by the students is 8 out of 10. Half believe that a month is too short a period and suggest that more time is offered as an optional placement. 98% consider that the Centre in which they were placed was sufficiently or very capable of teaching at the undergraduate level. Placing medical students in Primary Care teams is an essential part of today's medical teaching and is feasible within the present health system. The relationship between the University and the general physicians who act as tutors is seen as the main obstacle that needs to be overcome.

Community Health Centers↗
PubMed1992

Distinct mechanisms of inhibition of purified cardiac sarcolemma Ca(2+)-ATPase by two calmodulin antagonists.

The effects of calmidazolium and compound 48/80 were studied in four different states of activation of the purified Ca(2+)-ATPase from cardiac sarcolemma: "basal" or unactivated, activated by calmodulin, activated by phosphatidylserine, and activated by controlled trypsinization. When assayed in the presence of phosphatidylcholine as the sole phospholipid (basal state), the purified enzyme was resistant to inhibition by calmidazolium (0.1 to 3 microM). In the same range, calmidazolium inhibited the enzyme activated by controlled proteolysis as well as the calmodulin-activated enzyme regardless of the calmodulin concentration. The phosphatidylserine-activated enzyme was inhibited at higher calmidazolium concentrations due to non-specific trapping of the inhibitor by the excess of phospholipid. Addition of calmidazolium did not modify the K0.5 for calcium activation of ATP hydrolysis by the enzyme. The inhibition by calmidazolium was counteracted by Pi. Compound 48/80 also had no effect on the enzyme when only phosphatidylcholine was present and, like calmidazolium, it inhibited the calmodulin-activated enzyme and the phosphatidylserine-activated enzyme. The apparent Ki for inhibition by compound 48/80 was dependent on the calmodulin concentration. However, the enzyme activated by controlled trypsinization was insensitive to compound 48/80. Binding of 48/80 to the enzyme in the presence of phosphatidylserine or calmodulin reversed the increased affinity for Ca2+ caused by these activators.

Adenosine Triphosphate↗
PubMed1992

Effect of culture age, pre-incubation at low temperature and pH on the thermal resistance of Aeromonas hydrophila.

The thermal resistance of Aeromonas hydrophila strain NCTC 8049 was determined within the range 48 degrees-65 degrees C with a thermoresistometer TR-SC and McIlvaine buffer. The effects of culture age, pre-incubation at 7 degrees C and the pH of the heating menstruum were evaluated. The pattern of thermal death was dependent on culture age. Cells heated in the late logarithmic growth phase (15 h at 30 degrees C) were twice as resistant as those in the early stage (5 h at 30 degrees C), and the maximum D-value was obtained after 72 h incubation (5.5 total increase). The age of the cells did not affect z-values significantly. The heat resistance of cells incubated for 48 h at 30 degrees C increased (twice) after holding at 7 degrees C for 72 h. Pre-incubation at low temperature of older cultures (72 h, 30 degrees C) did not influence their D-values. Maximum heat resistance was found at pH 6.0 and minimal at pH 4.0. Decreasing the pH from 6.0 to 4.0 reduced D-values by a factor of 5. Although the strain studied was heat-sensitive (D55 degrees C = 0.17 min; z = 5.11 degrees C), survivor curves of cultures older than 50 h showed a significant tailing. Organisms surviving in the tails were only slightly more resistant than were the original population.

Aeromonas hydrophila↗
PubMed1992

Species of Pseudomonas obtained at 7 degrees C and 30 degrees C during aerobic storage of lamb carcasses.

A total of 268 strains of Pseudomonas isolated during storage life of lamb carcasses was identified to species level. One-hundred and thirteen strains obtained at 30 degrees C were Ps. fragi (51), Ps. lundensis (17), Ps. fluorescens biovars I (10), III (9) and VI (1), Ps. putida biovar A (8 strains) and unidentified (17 strains). Species and biovars isolated at 7 degrees C (155) were Ps. fragi (101), Ps. lundensis (32), Ps. fluorescens biovar I (6), Ps. putida biovar A (8) and unidentified (8). Numerical analysis (82% SSM, UPGMA) of 'psychrotrophic' and 'mesophilic' strains resulted in the formation of nine and eight clusters respectively. The dendrograms obtained exhibited similar structures. Most of the strains of Ps. lundensis and Ps. fragi clustered together. Strains of this latter species also joined the type strain of Ps. testosteroni and appeared included with phenons containing the Ps. putida strains. There were clusters made up exclusively of strains assigned to one biovar or group (Ps. fluorescens biovars I and II and unidentified). A high level of similarity was observed between clusters of Ps. fluorescens biovar I and those containing the Ps. fragi-Ps. lundensis complex (> 74% SSM) and Ps. lundensis (> 80%). The recovery of pseudomonads seemed to be affected by the sampling day.

Aerobiosis↗
PubMed1992

Numerical taxonomy of gram-negative, nonmotile, nonfermentative bacteria isolated during chilled storage of lamb carcasses.

A numerical taxonomic study using 75 characters was performed with 132 strains of gram-negative, nonmotile, nonfermentative bacteria selected on the basis of lack of motility and Gram reaction among 1,200 cultures isolated during aerobic storage of lamb carcasses. At the 80% similarity level (SSM), eight clusters were formed. Strains in clusters 1 to 6 could be identified as members of the family Moraxellaceae and, more specifically, as members of the Psychrobacter-[Moraxella] phenylpyruvica subgroup. Of these strains, clusters 1 and 2 (88 strains) were identified as [Moraxella] phenylpyruvica and cluster 3 (15 strains) was identified as Psychrobacter immobilis. Clusters 4, 5, and 6 were not identifiable with any species. Clusters 7 and 8 consisted of 14 strains considered nonmotile variants of Pseudomonas fragi. The highest separation indices corresponded to acid production from certain carbohydrates (melibiose, L-arabinose, and cellobiose). Although strains of Psychrobacter-Moraxella clusters were relatively frequently identified at the completion of slaughter, very few cultures were detected on spoiled carcasses. It appears, therefore, that this group of organisms has only low spoilage potential.

Animals↗
PubMed1992

[Masked Philadelphia chromosome: diagnostic implications in a case of chronic myeloid leukemia presenting in blast crisis].

We present a female patient with acute non-lymphoblastic leukemia (ANLL) and with haematologic features suggestive of its evolution from chronic myeloid leukaemia (CML), in which a bone marrow karyotype showing a "masked" Philadelphia (Ph) chromosome due to a variant translocation of complex type t(9;9;22)(q32;q34;q11) was found. We comment the peculiarities of this special Ph chromosome as well as the differential diagnostic problems between ANLL Ph(+) and CML with onset in blastic crisis.

Aged↗
PubMed1992

[Design and validation of a questionnaire for screening of venous insufficiency of the lower limbs].

OBJECTIVE: To carry out a questionnaire type test for screening of Chronic Venous Insufficiency (CVI) of lower limbs (LL) to be applied to clinical assistance. DESIGN: Observational type epidemiological study and validation of a test. LOCATION: Fuencarral Health Centre (Madrid). PATIENTS: 100 patients with venous alterations of the lower limbs (cases) and 100 without alterations (control group) selected from the register of the Centre. The inclusion criteria was the presence of truncular varicose veins and/or valvular insufficiency detected by ultra-sound (Doppler). MEASUREMENTS AND MAIN RESULTS: 20 variables were studied possibly associated with the disease and which could be collected by means of a questionnaire. From the epidemiological study, 13 simple questions with a YES/NO answer were chosen for the questionnaire, which collected information on the different variables selected. The maximum number of points of the test was 30. The value of each question was based on the strength of association (ODDS Ratio) and on the degree of reliability of the answers. The sensitivity and specificity of the test taking 14 points as the cutting point, was 82% in both cases. The ROC curve is indicated. CONCLUSIONS: Owing to the high prevalence of CVI of LL and to the possibilities of preventive measures if an early diagnosis is carried out, this questionnaire type test is considered useful among people attending the Health Centre and to be able to select those who require a more detailed and expensive diagnosis examination.

Adolescent↗
PubMed1992

[Serologic diagnosis of HIV (1988-1989)].

Determination of antibodies to HIV virus by the ELISA technique was performed in 27,652 serum samples from January 1988 to November 1989. Samples which were positive twice underwent the Western Blot technique. A 0.41% of positiveness to the virus was found in 1988 and a 0.34% in 1989. Confirmation of positive cases by Western Blot was statistically significant in 1989.

Blotting, Western↗
PubMed1991

Cytochrome c oxidase subunit II mRNA levels during T-lymphocyte proliferation and liver regeneration.

We studied here the variations in the mRNA levels of the mitochondrially-encoded subunit II of cytochrome c oxidase (COII) during the proliferation of thymocytes, splenic T-cells and hepatocytes. The COII mRNA levels increased during thymocyte proliferation and decreased when they were growth arrested. However, its levels remained nearly constant during splenic T-cell proliferation and liver regeneration after partial hepatectomy. The different pattern of COII gene expression in the cellular systems analyzed suggests that an increment in the oxidative metabolism could not always be necessary during cell proliferation.

Animals↗