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Biomedical subjects

L Rodríguez

Publications and source records attributed to L Rodríguez.

At least 73 records · Page 4Linked to original sources
PubMed1997

Intention to postpone sexual initiation among Puerto Rican female adolescents.

The purpose of this analysis is to examine the factors associated with intentions to initiate sexual intercourse among a group of female high school students in Puerto Rico. A large metropolitan high school was purposively selected for the study. The mean age of the girls who participated in the study (N = 133) was 16. 13% of the surveyed girls reported having had intercourse at some point in their lives. 45% indicated when answered that they were sure they would not initiate sex during the next year; 18% answered that it probably would not happen; and the others (28%) responded with an even 50-50 chance or more that it will probably happen. A multiple regression/correlation analysis showed that the mother's traditional sexual values along with the teen's own conventional behavior, traditional sexual values as well as a perception of conventional behavior by their peers were related to a lower expectation of sex initiation.

Adolescent↗
PubMed1996

Cloning and sequence analysis of the invertase gene INV 1 from the yeast Pichia anomala.

A genomic library from the yeast Pichia anomala has been constructed and employed to clone the gene encoding the sucrose-hydrolysing enzyme invertase by complementation of a sucrose non-fermenting mutant of Saccharomyces cerevisiae. The cloned gene, INV1, was sequenced and found to encode a polypeptide of 550 amino acids which contained a 22 amino-acid signal sequence and ten potential glycosylation sites. The amino-acid sequence shows significant identity with other yeast invertases and also with Kluyveromyces marxianus inulinase, a yeast beta-fructofuranosidase which has a different substrate specificity. The nucleotide sequences of the 5' and 3' non-coding regions were found to contain several consensus motifs probably involved in the initiation and termination of gene transcription.

Amino Acid Sequence↗
PubMed1996

Isolation and characterization of mutants as an approach to a transformation system in Kluyveromyces marxianus.

A method to obtain K. marxianus mutants has been developed. Different auxotrophic mutants were isolated by nystatin and snail-enzyme enrichment procedures using an incubation time of 2 h before adding the antibiotic or the enzyme respectively. All his mutants analyzed by complementation tests turned out to belong to the same complementation group. Some of them were transformed and complemented by the S. cerevisiae HIS3 gene. These non-reverting his3 mutants contain no heterologous sequence, which is essential to make them acceptable for application in the food industry.

Genes, Fungal↗
PubMed1996

Serological survey of small mammals in a vesicular stomatitis virus enzootic area.

Small mammals were captured in a Costa Rican dairy farm located in a vesicular stomatitis virus (VSV) enzootic focus, in order to determine which species were naturally infected by this virus. Monthly captures were performed from March 1989 to February 1990. Eighty-four individuals belonging to the orders Rodentia (n = 52), Insectivora (n = 31) and Marsupialia (n = 1) were captured. Only Sigmodon hispidus had neutralizing antibodies to VSV; among 21 animals, six had antibodies to Indiana, one to New Jersey, and two to both serotypes. In addition, groups of 40 sentinel mice (Mus musculus, strain C3H) were placed in cages distributed throughout the farm. Each group was exposed for 1 mo over a period of 1 yr. None of 312 sentinel mice developed antibodies against either VSV serotype. Based on these results, we believe that S. hispidus might be part of the natural cycle of VSV in this enzootic focus. Caged Mus musculus do not seem appropriate for monitoring VSV activity in this area.

Animals↗
PubMed1996

Double mitral valve orifice. Two-dimensional and Doppler echocardiographic diagnosis.

The purpose of this study was to demonstrate the usefulness of two-dimensional and Doppler echocardiography for diagnosing double mitral valve orifices (DMVO) in addition to identifying associated pathologies. We report five cases, three male and two female with an age ranging from 4 to 44 years old (mean age: 17 years), with the diagnosis of DMVO according to the following characteristics: using two-dimensional echocardiography on the short parasternal axis, both orifices were observed; apical in which the "seagull sign" was identified in both chambers, in addition to identifying the flows of each orifice by pulsed and codified color Doppler obtaining the corresponding gradients. With respect to the associated pathologies, all patients presented some type of malformation, such as subaortic ring, patent ductus arteriosus, coarctation of the aorta, bicuspid aorta and pulmonary stenosis. Using the color Doppler echocardiography allows an adequate anatomical and functional definition of DMVO.

Abnormalities, Multiple↗
PubMed1996

[Measurement of total serum IgE by enzyme immunoassay with three commercial reagents].

We measured total serum IgE in 14 patients with allergic diseases and 16 healthy subjects, using three commercial ELISA kits. The correlation of results among the three kits was analyzed using Passing and Bablock regression parameters. Results show that measurements of the different kits do not coincide. One kit shows differences using sera from normal subjects. There is no correlation among kits when using sera from allergic patients. It is concluded that it is not possible to determine exactly the amount of IgE using these kits, specially in subjects with elevated levels.

Adolescent↗
PubMed1996

Mothers' health-seeking behaviour in acute diarrhoea in Tlaxcala, Mexico.

This study, a cross-sectional survey, was conducted to assess how mothers take care of their children with diarrhoea and to develop a model of health-care seeking behaviour. Multistage sampling was used. Mothers whose children aged less than five years had suffered from diarrhoea in the last fortnight were included. Nurses interviewed the mothers to collect data. Variables included in the interview were: mothers' characteristics, children's characteristics, clinical data, treatment given by the mother, maternal health-seeking behaviour and mothers' information about diarrhoea and dehydration. Variables corresponding to the clinical data were grouped to identify dehydration signs and the need for medical care. Dehydration was defined as the presence of two or more of the following reported signs: thirst, sunken eyes, sunken fontanelle, or scanty urine. The need for medical care was defined as the presence of one or more of the following characteristics: illness lasting more than three days, vomiting, fever, bloody diarrhoea or dehydration. A sample of 747 mothers was obtained. Household treatments consisted of herbal teas to stop diarrhoea (52.3%), liquids to prevent dehydration (92.2%), symptomatic drugs (35.2%) and changes in feeding patterns (36.3%), which consisted in suppressing milk and dairy products and interrupting breast feeding (12.2%). Mothers sought medical assistance when they perceived a worsening of clinical conditions. Clinical signs statistically associated with their decision were: bloody diarrhoea, vomiting, illness longer than three days, weight loss, and fever. The signs of dehydration were not associated with health care-seeking because the mother did not recognise them. It is concluded that maternal educational programmes should emphasise, besides the proper use of oral rehydration therapy, teaching mothers to identify signs of dehydration as an indication to seek timely medical care.

Acute Disease↗
PubMed1996

[Dissolution velocity of different calcium preparations used in the clinical field].

BACKGROUND: Prescription of calcium supplements is a frequent practice, considering that diet is insufficient to cover daily requirements of this mineral. AIM: To study the dissolution velocity in an acid solution, of different commercial calcium supplements. MATERIAL AND METHODS: Hydrochloric acid was added to distilled water in increasing amounts to obtain a final pH of 6.9, 3.0, 2.5, 2.0 and 1.5. Eighteen commercial calcium preparations were incubated in these solutions for 60 min and dissolution velocity was measured as the percentage of elemental calcium found in solution after this incubation period. RESULTS: Calcium carbonate preparations had a pH dependent dissolution velocity, ranging from 0.67 +/- 0.8% at pH 6.9 to 77.15 +/- 17.5% at pH 1.5. Using the solution with pH 1.5, the dissolution velocity of different preparations varied widely from 56 to 100%. Calcium acetate, followed by calcium citrate and dicalcic phosphate were the salts in tablets with better dissolution velocities. Among powders and effervescent preparations, those containing calcium lactogluconate and citrate had the better dissolution velocities (95 to 115%), that were independent of the solution's pH. A studied preparation with integral bone had a very low dissolution velocity, not surpassing 33 mg of calcium per tablet. CONCLUSIONS: The dissolution velocity of different calcium carbonate preparations varies greatly and, in conditions of achlorhydria, it is negligible. Calcium lactogluconate and citrate dissolution velocities are independent of the solution's pH.

Calcium↗
PubMed1996

[Validation of a ultramicroELISA for detecting antibodies against hepatitis B surface antigen].

The results of a validation study of the ultramicroanalitical assay for the detection of antibodies against the hepatitis B surface antigen (UMELISA anti-HBsAg), which was carried out by comparing the results obtained with the Hepanostika anti-HBsAg, commercial diagnosis kit are presented. For this purpose, sera from the clinical assays of the Cuban recombinant vaccine against hepatitis B were used. With the first sera group (n = 30) it was obtained, 93.1% of sensitivity, 98.5% of specificity and a concordance of 94.3%. The correlation coefficient showed a similar trend of the results (p < 0.01) and no significant differences were found in the average geometrical titre (TPG) between both assays (p > 0.05). With the second group (n = 100), whose assays were carried out at the "Pedro Kouri" Institute of Tropical Medicine (PKI) and at the Immunoassay Center (IAC) simultaneously, it was observed a sensitivity of 96.25% in both centers, a specificity of 75% at the PKI and of 90% at the IAC, and a coincidence of 92% and 95%, respectively. The correlation coefficient presented similar values and there were no significant differences between the TPG obtained by the two methods (p > 0.05). The results attained show in general the validity of the new assay and the feasibility to put it into practice either for following up the infection, or for carrying out clinical assays of vaccine evaluations.

Enzyme-Linked Immunosorbent Assay↗
PubMed1995

Assessment of DNA damage in leukocytes from infected and malnourished children by single cell gel electrophoresis/comet assay.

The alkaline single cell gel (SCG) assay is a sensitive electrophoretic technique for detecting the presence of DNA single strand breaks and alkali-labile damage in individual cells. This technique was used to assess and compare the level of DNA damage in peripheral blood leukocytes/lymphocytes from well-nourished children with infection, well-nourished children with infection and under drug treatment, and from malnourished infected children with and without previous drug treatment. The present study shows that severe infection is associated with a significant increase in DNA damage. The average migration length was five times greater in severely infected well-nourished children compared to that found in healthy, well-nourished children. The results obtained in this study indicate that malnutrition is another factor associated with an increase in DNA migration. The average tail length for malnourished, severely infected children was twice as great as that obtained for cells from well-nourished, severely infected children. We also detected a variable increase in DNA migration associated with treatment for severe infection. Nevertheless, the excessive heterogeneity, the concurrent number of drugs used and the limited size of the treated population precludes an accurate assessment of which drugs were involved in the increase in DNA damage. Further studies will be necessary involving a large number of patients to address the relation between levels of DNA damage and specific kinds of infection, various drug treatments, and the type and severity of malnutrition. The increased level of DNA damage in severely infected and malnourished children could be related to negative effects such as a deficient immune response resulting in an increased susceptibility to malignant transformation.

Child↗
PubMed1995

[Cuban epidemic neuropathy. I. Viral isolation].

From the end of 1991 to June, 1993, an epidemic neuropathy affecting 50,963 persons occurred in Cuba. Two clinical forms of the disease were observed: the optic form (with or without peripheral manifestations, 52% of the cases) and the peripheral form (48%). The epidemiological studies revealed nutritional disorders, mainly a vitamin B complex deficiency due to economic difficulties faced by the country in the "special period". Smoking habit and alcohol consumption were identified as risk factors, particularly for the most severe forms of the disease. In the virological studies of the cerebrospinal fluid (CSF) a Coxsackie 9 virus was isolated in Vero cells in 4% of the cases, as well as another agent with mild cytopathogenic effect in 80% of the samples. Sixty seven percent of the CSF samples inoculated to lactating mice caused the disease or the death of the animals. The viral persistence was confirmed in the cerebrospinal fluid during al least 21 days in a group of patients, and for a year in another group.

Animals↗
PubMed1995

[The use of ELISA and ultramicro ELISA in identifying a Coxsackie A9 strain isolated during the epidemic of neuropathy in Cuba].

During 1993 an outbreak of epidemic neuropathy characterized by 2 major clinical forms: the optic neuropathy and peripheral neuropathy, occurred in our country. Although the cause of the disease was considered to be multifactorial (mainly due to neurotoxic agents and to nutritional deficiency) an Enterovirus was isolated from the cerebrospinal fluid of a patient (strain 47/93, IPK) which was subsequently classified as a Coxsackie A9 virus (Cox A9) by the neutralization test, and using pools of Lim Benyesh Melnick (LBM) serum. Results obtained during the application of ELISA and ultramicro ELISA techniques for the identification of this agent from the supernatant of a culture of infected cells are reported, as well as the detection of antibodies to the strain found within populations with high and low incidence rates of the disease.

Antibodies, Viral↗
PubMed1995

[A comparison of the results obtained in IgM serology and anti-Coxsackie A9 (strain 47) neutralization in cases of epidemic neuropathy and their contacts].

A number of 213 monosera from patients presenting with epidemic neuropathy and their contacts was studied by indirect immunofluorescence and neutralization tests with the aim of demonstrating the presence of serum IgM and neutralizing antibodies against the strain 47/93 IPK identified as a Coxsackie A9 virus. The mean age of the patients ranged from 20 to 59 years and positivity to both techniques was not found to be predominant for one or another sex. No significant difference was observed with respect to results obtained between patients and contacts with the techniques used for the study.

Adult↗
PubMed1994

Radionuclide ventriculography in dynamic cardiomyoplasty.

Dynamic cardiomyoplasty improves ventricular function by increasing pump function and by limiting cardiac dilatation. The aim of this study was to assess long-term myocardial performance by radionuclide ventriculography on dilated cardiomyopathy patients subjected to cardiomyoplasty. Thirteen survivors were included. Radionuclide ventriculography was performed one week before surgery and one year later. Five patients were also studied two years following surgery. The left ventricular ejection fraction (LVEF), end-diastolic volume (EDV) and ventricular amplitude ratio (VAR) to assess mitral regurgitation were measured. Every case after one year showed a non-significant increase in LVEF. However, the decrease in EDV and in VAR was significant (p < 0.01). No significant difference in these values was found after two years. We conclude that the effects of cardiomyoplasty--reduction of cardiac dilatation, wall stress and mitral regurgitation--are more evident during the first year after surgery. Thereafter, a certain stabilization is observed.

Adult↗