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Biomedical subjects

M Ríos

Publications and source records attributed to M Ríos.

13 recordsLinked to original sources
PubMed1996

[Time series in the epidemiology of typhoid fever in Spain].

BACKGROUND: The incidence of typhoid fever in Spain from January 1982 to December 1993 was studied with the aim of analyzing how the disease has evolved over these years and predict its future behavior in order to facilitate prevention by the public health care organizations and centers. MATERIAL AND METHODS: The Box-Jenkins temporary series theory was used. The data corresponded to the declared disease cases throughout Spain published in the Epidemiology Bulletin by the Carlos III Health Center and the Department of Health and Welfare. RESULTS: The ARIMA (0,1,1) (0,1,1)12 model was selected to report the data obtained. The analytical results demonstrated a exponential decreasing tendency with an annual seasonal pattern in incidence observed in this disease peaking in the months of July, August and September and decreasing in the declared cases in December, January and February. A mathematical expression was also obtained to allow the prediction of the disease behavior in the future. CONCLUSIONS: Prophylactic measures should be taken in the summer months. A disease incidence greater than that foreseen by the mathematical formula obtained would express a failure in epidemiologic surveillance, and thus the results of this study may be used as a quality control of the preventive measures.

Humans↗
PubMed1995

Effect of interferon and 2',5'-oligoadenylates on rotavirus RNA synthesis.

Based on the antiviral effect of interferon on rotavirus replication the inhibitory effect of 2',5'-oligoadenylates on MRNA and double-stranded RNA synthesis was studied using an in vitro assay. The chemically synthesized oligonucleotides were used to determine several characteristics of the inhibitory effect, such as chain length, presence of phosphate residues at the 5'-end, and the 2',5'-phosphodiester bond itself. In vitro transcription was inhibited by oligos with 5 or more adenine residues at a final concentration of 100 microM or greater. This result makes rotavirus transcriptase different from other viruses in which the inhibitory effects are associated with dinucleotides and trinucleotides. The inhibitory effect was increased when the oligo contained a phosphate residue at the 5'-end; in this case, inhibition was also seen at lower oligo concentrations as well as at shorter oligo chain length. The study of the kinetics of inhibition showed that the inhibition by p(A2'p5')(3)3A was competitive with a Ki value of 256 microM. The effect of the oligonucleotides on the in vitro viral RNA replication showed that the 2',5'-oligoadenylates were not able to significantly inhibit the in vitro rotavirus RNA synthesis. The lack of inhibition in the in vitro assay was very peculiar since RNA transcription and replication involves the viral RNA polymerase, VP1.

Adenine Nucleotides↗
PubMed1995

Antiviral activity of phosphonoformate on rotavirus transcription and replication.

The antiviral effect of foscarnet (PFA) on the replication of rotavirus, a member of the Reoviridae, was studied. The pyrophosphate analogue is an effective inhibitor of several viral polymerases acting on the enzyme pyrophosphate binding site. Replication of rotavirus in MA104 cells using different u.o.i. was inhibited by PFA in a concentration dependent manner, due to the inhibition of both plus- and minus-strand RNA synthesis. The addition of PFA to infected cells was specific for the inhibition of viral replication since uninfected cell incubated at the same PFA concentrations did not exhibit any cytotoxic effect. The 50% inhibitory effect of PFA on in vitro mRNA synthesis was obtained at a concentration of 150 microM. Over 80% of the in vitro minus-strand RNA synthesis was inhibited at a concentration of 320 microM, when PFA was assayed using replicase-enriched cell infected fraction. The results suggest that the effect may be due to an interaction of PFA with the viral polymerase, since this protein catalyses both plus- and minus-strand RNA synthesis. The results of experiments using the temperature-sensitive viral polymerase mutant show that the mutant is less sensitive to PFA, suggesting that this polypeptide is the target for PFA.

Animals↗
PubMed1995

[The IPPS questionnaire in patients and controls. Psychometric validation].

The translation into Spanish of the AUA/International Prostatic Symptom (AUA/IPS) Score hadn't been validated in spanish. METHODS. AUA/IPS questionnaire was self administered by 103 consecutive patients and by 24 healthy volunteers. An alternative formulation to question 4 (ALT-4) was added. RESULTS. 51 patients (49%) and 17 controls (79%) completed al questions (Feasibility). Reliability was measured by: a) Crohnbach's alpha (0.68 and 0.70 with ALT-4) b) Kendall's coefficient of concordance (0.097, significance < 0.001) and c) retesting 17 patients within 2 months. The relation of the AUA/IPS scores with quality of life (Construct validity) showed a Spearman's correlation coefficient of 0.57 (confidence = 0.0001), and 0.52/0.0004 with ALT-4. The relation with uroflowmetry (Concurrent empirical validity) was poor as shown in ROC curves. CONCLUSIONS. The Spanish version of the AUA/IPS questionnaire given in an easy format improves feasibility without alteration of reliability or validity. The relation of the AUA/IPS score with uroflowmetry is poor, although the questionnaire can be considered valid and reliable.

Case-Control Studies↗
PubMed1995

Discriminant analysis algorithm based on a distance function and on a Bayesian decision.

We propose a new algorithm for the allocation of an individual to one of several possible groups or populations. The algorithm enables us to define a finite partition over the sample space, based on distance function. This partition is used, jointly with the application of a standard Bayesian decision rule, to allocate individuals to the populations. The algorithm also provides a measure of the allocation confidence for each individual, in a similar manner to that of logistic regression. The error rates for classification are also computed using the leave-one-out method. Results are compared with those obtained with other discriminant analysis techniques previously reported: Fisher's linear discriminant function, the quadratic discriminant function, logistic discrimination, and others.

Adolescent↗
PubMed1994

Increased incidence of thyrotoxicosis after iodine supplementation in an iodine sufficient area.

UNLABELLED: The aim of this study was to determine the incidence rate of thyrotoxicosis (TT) before and during dietary-iodine supplementation in an iodine-sufficient area. POPULATION: the study was carried out in Vigo, South Galicia (northwest of Spain), from January 1977 to December 1989. The mean population throughout the study period was 267,330 inhabitants (47% males and 53% females). From January 1985, a mandatory consumption of iodinized salt on the whole population started in Galicia. This region was considered as an iodine-deficient area but Vigo is an iodine-sufficient area. MEASUREMENTS: all newly diagnosed TT cases in Vigo city within the study period were included in this study. Diagnosis of TT was based on the clinical manifestations, an elevated level of T4 and suppressed TSH values. The difference between diffuse and nodular forms of goiter was assessed by scintigraphy. The average incidence rate (AIR) was determined in two periods, before (period A, 1977-1984) and during (period B, 1985-1989) iodine supplementation. RESULTS: the AIR throughout the whole study period was 4.89 new cases per 100,000 population, 95% confidence limits 4.16 to 5.63; AIR was 1.34 for males and 8.03 for females. AIR in period B was significantly higher with respect to period A, 7.68 and 3.10 per 100,000 respectively. The confidence interval for the difference was from -20.4 to 30.1, p < 0.05. The increase of the incidence of TT was comprised of both nodular and diffuse goiters. CONCLUSIONS: dietary iodinesupplementation in iodine-sufficient areas may induce an increase of the incidence of TT.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

[CD10(CALLA)-negative acute lymphoblastic leukemia. A group with a bad prognosis].

The results of 188 patients with acute lymphoblastic leukemia, studied between 1985 and 1990, showed that 8 cases were CD10 negative, Dr, and CD19 positive. These findings indicate cell dedifferentiation and poor prognosis. The patients age ranged from 2 to 30 years, with a mean of 11 years. The male/female ratio was 5/3. Lymph node enlargement and splenomegaly were found in the 8 patients. With the exception of one patient in whom leucopenia was present, the white cell counts were always higher than 30,000/dl. The karyotype was studied in four cases, and all of them were hyperdiploid. This is the first report in Venezuela of cases with acute lymphoblastic leukemia - CD 10 negative.

Adolescent↗
PubMed1991

[Nutritional study of alcoholics with specific reference to calcium and phosphorus].

We performed a nutritional study of 80 alcoholic males at least 15 days after an acute episode of alcoholic intake. 43 patients were intermittent drinkers with mean age 37.9 years and 37 patients were continuous drinkers with mean age 440.30 healthy subjects were studied as controls. Body mass index was 23.7 (range 19.2-37.9) in intermittent drinkers compared to 23.1 (range 18.1-29.8) in continuous drinkers (NS). Wine was the main alcoholic beverage in 70% and 89%, respectively. Mean daily alcohol intake was 170 g for 17 years and 358 g for 23 years, respectively. Mean caloric intake and % of calories from alcohol were 3387 and 42% for intermittent compared to 4271 and 66% for continuous drinkers, respectively. Daily calcium intake was 757 g and 774 g in each group. Alcoholic beverages supplied 16% and 34% of calcium intake, respectively. The intake of phosphorus was adequate. Alcoholic subjects did not manifest anemia or hypoalbuminemia, compared to controls. The present study fails to disclose significant caloric and protein undernutrition in alcoholic subjects. However, the intake of calcium is inadequate and a high percentage of it is provided by alcoholic beverages. This deficiency in conjunction with alcoholic damage to intestinal mucosa may lead to osteopenia in alcoholic patients.

Adult↗
PubMed1988

[Heterologous hormonal regulation in the mammary gland].

Mammary gland growth and differentiation are largely dependent on a complex and interrelated action of many different hormones which makes the mammary tissue a very suitable one for the study of heterologous hormonal regulation. This type of control is analyzed by two different approaches: 1. The participation of estradiol in prolactin action during lactation, and 2. The role of glucocorticoids and thyroid hormones in the control of functional activity of rat mammary gland beta-adrenergic receptors.

Animals↗
PubMedDate not supplied

Hormonal modulation of the rat mammary gland gamma-glutamyltranspeptidase.

1. The in vivo effect of estradiol and domperidone (a hypophysis stimulator of prolactin secretion) in immature ovariectomized-adrenalectomized and hypophysectomized rat mammary gland was studied. 2. gamma-Glutamyltranspeptidase activity was used to evaluate the role of estradiol in the specific response of the gland to prolactin. 3. Our results suggest that the activity of gamma-glutamyltranspeptidase, like casein and lactose synthetase, is part of the specific response of the gland to prolactin.

Adrenalectomy↗