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M Rivero

Publications and source records attributed to M Rivero.

At least 55 records · Page 3Linked to original sources
PubMed1997

[Trichinellosis: study of 2 outbreaks in Navarre].

BACKGROUND: We present two outbreaks of trichinosis occurred in the last two years in Navarre. METHODS: After the detection of the initial case, an epidemiological study of all people presumably infected was carried out. We used the latex agglutination and ELISA tests to detect specific antibodies. We studied the characteristics of the infested meat, as well as the clinical symptoms, eosinophil counts and serologic status of the subjects. After three and twelve months those items were again monitored. RESULTS: 71 subjects who had ingested the infected meat were detected. Of them, 67 (94.3%) were enrolled in the study, 34 being involved in the first outbreak and 33 in the second. 15 (22.5%) of the 67 cases had symptoms suggestive of trichinosis, 30 (44.7%) had hypereosinophilia, and 25 (38%) had positive serologic test results. 25 subjects (38%) were diagnosed as having trichinosis. Two groups were made according to the characteristics of the meat consumed: 34 subjects (50.7%) had ingested thoroughly cooked meat (group A), whereas 33 (49%) had ingested poorly cooked meat (group B). After three months, only 5 patients were symptomatic and 10 had a high eosinophil count. After 12 months, all subjects were asymptomatic, had normal eosinophil counts and negative serologies. CONCLUSIONS: 1) An epidemiological survey and serologic determinations for trichina should be carried out when studying hypereosinophilia. 2) It is important to insist on the necessity of veterinary inspection of home-made pork products. 3) The ingestion of poorly cooked pork products increases the risk of Trichinella infection.

Animals↗
PubMed1997

Hepatitis C virus recurrence after liver transplantation: relationship to anti-HCV core IgM, genotype, and level of viremia.

OBJECTIVES: Factors that determine the severity of hepatitis C virus (HCV)-recurrent disease in patients undergoing orthotopic liver transplantation (OLT) for HCV cirrhosis have not been clearly identified. To address this issue, we evaluated the histological and virological outcome in 25 patients who underwent OLT for HCV cirrhosis. METHODS: HCV-RNA was detected by qualitative and quantitative polymerase chain reaction. The HCV genotype also was determined by polymerase chain reaction. Anti-HCV core IgM was tested by ELISA. Disease severity was expressed as a histological score. RESULTS: Sixteen patients had evidence of HCV-recurrent disease. HCV-RNA levels before transplantation (p = 0.029) and after transplantation (15 days, p = 0.004; 90 days, p = 0.040; 360 days, p = 0.010) were significantly higher among patients who subsequently developed recurrent hepatitis than among those who did not. The presence of anti-HCV core IgM before (p = 0.044) and after OLT (15 days, p = 0.017; 90 days, p = 0.037; and 360 days, p = 0.040) was significantly related to recurrence of hepatitis. The genotype was not related to the level of viremia, to the prevalence of recurrent hepatitis, to the presence of anti-HCV core IgM, or to disease severity. CONCLUSIONS: The recurrence of HCV hepatitis in patients undergoing OLT for HCV cirrhosis is related to higher levels of viremia and the presence of anti-HCV core IgM, but not to the HCV genotype. However, disease severity is not related to viremia levels, HCV genotype, or positivity of anti-HCV core IgM.

Adult↗
PubMed1997

[Usefulness of preoperative location tests in primary hyperparathyroidism].

The utility of preoperative parathyroid location in primary hyperparathyroidism (pHPT) remains controversial. In this retrospective study are analysed noninvasive techniques prior to surgical neck exploration of 11 patients with pHPT, ten adenomas and one hyperplastic parathyroid glands. Localization test were performed 24 times. Ultrasonography allowed correct localization of 5 of 7 cases, computer tomography 2 of 6, scintigraphy 2 of 4 and nuclear magnetic resonance 1 of 7. This exploration was doubtful in a patient, and two false-positive nuclear magnetic resonance were found. The low yield of these tests makes them unnecessary in the evaluation of patients undergoing surgery for pHPT, because the cost is not justified.

Adult↗
PubMed1996

[Immunologic characteristics of undernutrition. I. The undernourished patient in nutritional recovery].

Malnutrition in children is a well known critical factor that determines immunocompetence changes with altered immune response and higher risk to many diseases, especially in developing countries. Moreover, it is related to increased morbi-mortality rates mainly due to infections. For those reasons, 12 undernourished children, age 5 to 24 months were studied along 8 weeks at the Nutritional Recovery Center of Chiquinquira Hospital in Maracaibo, Venezuela. There were 5 cases of kwashiorkor, 5 marasmatics, 1 mixed marasmus/kwashiorkor and 1 case with moderate malnutrition. After a control blood sample was taken and cutaneous tests were done, a nutritional recovery program was began. At regular time intervals and at the end of the study, tests were done again by measuring seric immunoglobulins (IgG, IgA, IgM), secretory IgA (IgAs), C3 and C4 complement, lymphocytic sub-populations, and auto antibodies; cutaneous hipersensitivity tests were also done. As a control group, 10 apparently healthy children of matching age and sex were also studied with the same parameters. Results show that basal seric Igs did not differ significantly from the control group and did not change along the recovery program period, but there was a significant decrease in IgAs at all times of the study. C4 did not change and C3 was lower than control (p < 0.05) but returned to normal value at the end of the recovery period. CD3 and CD4 lymphocytes showed the same pattern. Only two patients showed positive skin tests and auto antibodies were not detected. It is concluded that there is indeed an altered immune competence with low levels of C3, IgAs, and CD3-CD4 lymphocytes that is reversible after nutritional recovery.

Antigens, CD↗
PubMed1994

Determination of plasma fatty acid composition in neonates by gas chromatography.

Total fatty acids in plasma of neonates have been analysed as their methyl esters by gas chromatography. They were separated on a capillary column coated with a SP-2380 stationary phase. As little as 100 microliters of plasma is used for the analysis. The extraction procedure was performed with dichloromethane-methanol (2:1) and fatty acids were methylated with boron trifluoride-methanol. The quantification of fatty acids is based on an internal standard method. Absolute values (micrograms fatty acid per 100 microliters plasma) are given together with relative values (%). At a signal-to-noise ratio of 3, the detection limits for flame ionisation detection are between 0.08 to 0.51 ng. The high sensitivity and precision permits the effective determination of the fatty acids in neonate plasma.

Arachidonic Acid↗
PubMed1993

Trans fatty acid content of human milk in Spain.

The C18 fatty acid fraction of 38 samples of mature human milk from Spanish women was analyzed using capillary gas chromatography. The average content of trans fatty acids found in these samples represented 0.95% of total fatty acids. This value is lower than the percentage found in human milk from other developed countries in which the consumption of hydrogenated fat is higher. Trans fatty acid content in human milk has been related to the types of fats and oils present in the diets of the nursing mothers. According to the results obtained in this survey, we can also conclude that the amount of trans forms in breast milk lipids is lower than the trans content found in infant formulas in Spain.

Adolescent↗
PubMed1990

Recovery study in Mg-deficient rats given an organic source of Mg.

Recovery from Mg deficiency was studied in rats given an organic source of Mg derived from yeast (Saccharomyces cerevisiae) cultured in an Mg gluconate-enriched medium, as the only source of Mg. Magnesium was given either at a rate above the RDA or as a supplement to the regular laboratory diet at the rate of 70 mg Mg/100 g food, of which 40 mg Mg was in the form of MgCO3 and the remaining 30 mg Mg was in the form of the organic product under study. The results showed a good degree of digestive and metabolic utilization of the organic compound, which led to the recovery of normal Mg levels in blood and bone by the end of the 1st week of treatment, and in muscle by the 3rd week of treatment. Muscle Mg content appears to be a good indicator of deficiency. Supplementation above the RDA failed to improve recovery rates in deficient animals.

Animals↗
PubMed1989

Nutritional availability of magnesium and calcium in magnesium-supplemented diets.

The nutritive utilization of magnesium and calcium was studied using two different formulations of Mg: MgCO3 and an organic dietary Mg preparation. The influence of supplementation with the latter was also studied. The dietary organic magnesium did not modify food intake, which remained adequate in all animals used in the present experiments. Magnesium in both inorganic compound and organic preparation form was well absorbed; furthermore, absorption levels of the latter remained quite stable throughout the different experimental periods. Mg balance in both muscle and femur was similar in all groups studied. Digestive utilization of Ca and Ca content in the longissimus dorsi were higher in animals fed the organic Mg preparation while Ca levels in blood and femur were not affected.

Animals↗
PubMed1989

[Seroepidemiologic study of hepatitis A virus among children of Maracaibo, Venezuela].

With the purpose of determining the incidence of Hepatitis A virus infection, we determined the presence of antibodies against this virus (anti-VHA) with the ELISA technique in 209 children from Maracaibo city of different socioeconomic levels, ages ranging from 6 months to 12 years. At the same time, we investigated the incidence of a recent infection through IgM antibodies for Hepatitis A (anti-VHA IgM) using the same ELISA technique. We found a global positive incidence of 46.4% for all ages. Individual ages studied showed 31% seropositivity in children less than one year old and a higher seropositivity in children between 9 and 11 years old (50-76.4%). There were noticeable differences in seropositivity in relation to social economic condition observing a higher percentage in children of low social economic level. A recent infection was demonstrated after the second year of life (60%) and a variable percentage through all pediatric ages studied. There was no recent infection detected in children under one year of age which suggests that antibodies anti-VHA obtained transplacentally can last at least for the first year of life as it does with other virus.

Child↗
PubMed1987

Bacterial chemotaxis. Cell flux model, parameter measurement, population dynamics, and genetic manipulation.

In this paper, we summarized our recent efforts toward accomplishing four key goals important for control of microbial population dynamics in nonmixed systems: (1) derivation of a cell population flux model based on individual cell properties; (2) measurement of the population random motility and chemotaxis parameters appearing in this model using a simple experimental assay; (3) quantitative understanding of the effects of cell motility and chemotaxis properties on microbial population dynamics; and (4) manipulation of chemotactic responses by genetic modification.

Bacteria↗