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Biomedical subjects

C Becerra

Publications and source records attributed to C Becerra.

At least 19 recordsLinked to original sources
PubMed2006

Estimation of canine intestinal parasites in Córdoba (Spain) and their risk to public health.

The prevalence of gastrointestinal parasites in dogs was studied in the province of Córdoba (southern Spain), with special attention to those parasites that can be transmitted to man. The experiment was completed with the examination of soil samples from public parks and city gardens. The study was carried out over a population of 1800 animals entered in the Control Animal Centre (CECA) by coprological methods, and within this group, 300 dogs were sacrificed and necropsied. The prevalence of any intestinal parasitic infection was 71.33%. The following parasites of the gastrointestinal tract were recorded: Isospora canis (22%), Isospora (Cystoisospora) spp. (10.22%), Sarcocystis (2.5%), Hammondia/Neospora (1.94%), Giardia canis (1%), Dipylidium caninum (13.2%), Taenia hydatigena (7.66%), Taenia pisiformis (4%), Uncinaria stenocephala (33.27%), Toxascaris leonina (14.94%), Toxocara canis (17.72%) and Trichuris vulpis (1.66%). Related to public health, it is important to point out the presence of T. canis only in puppies younger than one year and Uncinaria, more frequent in adult dogs. Soil samples of parks revealed the presence of eggs of Toxocara, and it suggests the existence of real risk for human infection.

Animals↗
PubMed2003

The role of Doppler studies in predicting individual intrauterine fetal demise after laser therapy for twin-twin transfusion syndrome.

OBJECTIVE: To investigate the role of Doppler studies in predicting individual fetal demise in patients scheduled for selective laser photocoagulation of communicating vessels (SLPCV) for twin-twin transfusion syndrome (TTTS). METHODS: Doppler studies of the umbilical artery, umbilical vein, ductus venosus, tricuspid valve regurgitation and middle cerebral artery were performed in the donor and recipient twins before and 24 hours after SLPCV. Results were analyzed cross-sectionally and longitudinally. As multiple comparisons were made, an a priori alpha rejection was set at P < 0.001. RESULTS: One hundred and ten consecutive patients were available for analysis. Overall fetal survival was 68.6% (151/220) with at least one survivor in 88.2% (97/110) of cases. Absent or reversed end-diastolic velocity in the umbilical artery of the donor twin was the only preoperative Doppler result predictive of intrauterine fetal demise (IUFD) (10/15, 66.7%, P < 0.001). Postoperatively, reversed flow during atrial contraction in the ductus venosus of the donor twin showed a trend towards prediction of IUFD of this fetus (4/5, 80%, P = 0.007). No other Doppler studies, including the longitudinal analyses, were predictive of IUFD. CONCLUSIONS: Our data suggest that preoperative absent or reversed end-diastolic velocity in the umbilical artery may be useful in predicting individual fetal demise of the donor twin in TTTS patients scheduled for SLPCV. This may reflect the role of decreased individual placental mass that may be associated with some donor twins. The inability of other Doppler studies to predict individual IUFD may be explained preoperatively by the effect of the interfetal vascular connections on the individual Doppler signals and postoperatively by the effect of surgery or the timing of the assessment. Our findings may be important in patient counseling, in furthering understanding of the disease, and perhaps in improving surgical technique.

Cross-Sectional Studies↗
PubMed2003

Phase II study of pemetrexed disodium (Alimta) administered with oral folic acid in patients with advanced gastric cancer.

BACKGROUND: The aim of this study was to assess the activity of pemetrexed in patients with advanced gastric cancer. PATIENTS AND METHODS: Thirty-eight eligible patients (median age 60 years) received pemetrexed 500 mg/m(2) every 3 weeks. Since toxicity was considerable in the first six patients, the protocol was amended to supplement subsequent patients with oral folic acid (5 mg/day on days -2 to +2 of every cycle). RESULTS: Among 36 stage IV patients evaluable for efficacy (six non-supplemented\30 supplemented), there were two complete and six partial responses. The response rate was 21% (95% confidence interval 8% to 32%) according to intention-to-treat analysis. All responding patients were in the supplemented group. The median duration of response was 4.6 months and the median survival was 7.8 months. Five of six non-supplemented patients (83%) developed grade 3/4 neutropenia; two (33%) unsupplemented patients discontinued; two (33%) patients died due to toxicity. In the supplemented group, 12 of 32 patients (37%) had grade 3/4 neutropenia. None of the supplemented patients discontinued treatment due to hematological toxicity. Severe non-hematological toxicities were infrequent. CONCLUSIONS: The activity of pemetrexed is promising in light of the tumor burden in these patients (all patients were stage IV and 39% had three or more organs involved). Toxicities were remarkably decreased with folic acid supplementation. Combination studies are warranted.

Adenocarcinoma↗
PubMed2001

Leukotoxicity of pyoverdin, production of reactive oxygen species, and effect of UV radiation.

Pyoverdin was purified by solvent extraction, gel filtration, and ionic exchange chromatography. Assays of cytotoxic of pyoverdin were done with human leukocytes and macrophages from the peritoneum of mice. Both cell quantities showed a significant reduction. Death was followed by lysis in a dose-dependent form. The mechanism of action of pyoverdin involved the stimulation of reactive oxygen species (ROS) measured by Nitroblue Tetrazolium (NBT) reaction and chemiluminescence (CL). UV radiation at 368 nm increased the leukotoxicity; expositions of 5 min were enough to photostimulate the effect of pyoverdin on cellular oxydative metabolism, which increased between 35.4 and 53.2%. Genestein, an inhibitor of tyrosine kinases, counteracted the ROS stimuli of pyoverdin, suggesting endocytic mechanism of action for this pigment. The little chloroquine interference on oxydative stress indicated that intraphagosomal pH and the stimuli of reactive nitrogen intermediaries (RNI) seem to be of less importance than ROS in pyoverdin action on leukocytes.

Bacterial Proteins↗
PubMed2000

Does perchlorate in drinking water affect thyroid function in newborns or school-age children?

Perchlorate is known to suppress thyroid function by inhibiting uptake of iodide by the human thyroid at doses of 200 mg/day or greater. A study was conducted to investigate the potential effects of perchlorate in drinking water on thyroid function in newborns and school-age children. A total of 162 school-age children and 9784 newborns were studied in three proximate cities in northern Chile that have different concentrations of perchlorate in drinking water: Taltal (100 to 120 micrograms/L), Chañaral (5 to 7 micrograms/L), and Antofagasta (non-detectable: < 4 micrograms/L). Among schoolchildren, no difference was found in thyroid-stimulating hormone levels or goiter prevalence among lifelong residents of Taltal or Chañaral compared with those of Antofagasta, after adjusting for age, sex, and urinary iodine. No presumptive cases of congenital hypothyroidism were detected in Taltal or Chañaral; seven cases were detected in Antofagasta. Neonatal thyroid-stimulating hormone levels were significantly lower in Taltal compared with Antofagasta; this is opposite to the known pharmacological effect of perchlorate, and the magnitude of difference did not seem to be clinically significant. These findings do not support the hypothesis that perchlorate in drinking water at concentrations as high as 100 to 120 micrograms/L suppresses thyroid function in newborns or school-age children.

Age Distribution↗
PubMed1998

[Prevalence of anemia in pregnancy, Pucallpa Regional Hospital, Perú].

Population based health surveys in Peru show that the general fertility rates, proportion of pregnant adolescents, and maternal and child morbidity are higher in the jungle regions than in other parts of the country. Endemic intestinal parasitic diseases increase the risk of anemia in pregnant women already suffering from iron, folic acid, and other nutritional deficiencies. This is the most common complication of pregnancy in many Latin American countries and is often associated with premature labor, low birthweight, and perinatal mortality. There are very few studies on this subject based on jungle populations and no reliable estimates of the prevalence of anemia in local pregnant women. The present study was designed to determine the prevalence of anemia in pregnant women attending the Regional Hospital in Pucallpa, located in the Peruvian jungle, from January 1993 to June 1995. This cross-sectional study, which was based on the registries of prenatal and childbirth services encompassing 1,015 pregnant women, looked into the potential association between anemia and such variables as the mother's chronological age, schooling, previous pregnancies, and weight at the beginning of pregnancy. Maternal hemoglobin levels were compared with the newborns' weight at birth. The prevalence of anemia in this population sample was 70.1%. This value was not modified when adjusted for maternal age, schooling, or interval between births. Anemia prevalence was directly related to the number of previous pregnancies and inversely related to weight gain during pregnancy. The perinatal mortality rate was 37.7 per 1,000 births. Neither this rate nor the birthweights were associated with the mother's degree of anemia. A multivariate regression analysis showed that maternal body weight at the start of pregnancy (P = 0.0001), weight gain during pregnancy (P = 0.0001), and the number of pregnancies (P = 0.008) are predictors of birthweight. Results showed that the high prevalence of anemia in Pucallpa's pregnant women is not associated with low birthweight or a high perinatal mortality rate. Future studies should investigate the principal causes of anemia in the pregnant women of Pucallpa and how the disease affects the psychomotor development of their offspring.

Adolescent↗
PubMed1997

Humoral and cellular immune responses to experimental Fasciola hepatica infections in goats.

Humoral and cellular immune responses to Fasciola hepatica excretory-secretory products (ESPs) in primary and secondary experimental infections in goats were studied. Primary infection induced the development of chronic subclinical fascioliasis that did not affect the establishment of flukes coming from the secondary infection, as the same percentages of recovered flukes were found in both groups. The specific IgG response to F. hepatica ESPs was similar in primary and secondary infections; challenge flukes did not induce any modification in the IgG response. The specific lymphocyte response to F. hepatica ESPs was absent in most of the infected goats, both primarily and secondarily infected. A modulation of the nonspecific cellular responses to mitogens was also observed. All infected goats showed a reduced proliferative response to concanavalin A and phytohemagglutinin. According to our results, humoral and cellular responses to F. hepatica ESPs in goats have no protective effect on the establishment of flukes and the development of disease in either primary or secondary infections.

Animals↗
PubMed1997

Triclabendazole treatment in experimental goat fasciolosis: anthelmintic efficacy and influence in antibody response and pathophysiology of the disease.

A controlled test of the efficacy of triclabendazole against all stages (early immature, late immature and mature) of Fasciola hepatica has been performed in experimentally infected goats. The influence of triclabendazole treatment on the pathophysiology of the disease, in terms of haematological parameters and serum enzyme levels, and in the dynamics of production of specific antibodies to excretory/secretory products (ESP) of F. hepatica were also examined. Goats were orally infected with 200 viable metacercarie and treated at 4, 8 and 16 weeks postinfection (PI) with triclabendazole at the dose rate of 10 mg kg-1 body weight. The drug can be regarded as highly effective against mature (100%) and late immature (99.2%) flukes and effective against early immature flukes (94.9%). A moderate anaemia was found associated with the presence of late immature and mature flukes in bile ducts. Treatment with triclabendazole, by eliminating most of these flukes, largely reduced haematological alterations. Serum levels of the enzymes aspartate aminotransferase, lactate dehydrogenase and gamma-glutathione transferase reflected hepatic damage during goat fasciolosis. Early treatment (at 4 weeks PI) prevents the development of both parenchyma and bile ducts lesions; treatment at 8 weeks PI only prevents bile ducts lesions and treatment at 16 weeks PI has no appreciable effect on the development of the main hepatic lesions. The antibody response to F. hepatica ESP, as measured by enzyme-linked immunosorbent assay, was also affected by treatment with triclabendazole. In all treated animals a peak in antibody levels was observed between weeks 9 and 13, followed by a drop whose magnitude depended on the efficacy of treatment. In those animals in which triclabendazole was highly effective, antibody levels fell back to negative values similar to those recorded preinoculation at 18-21 weeks PI.

Analysis of Variance↗
PubMed1991

[Fetal hemoglobin in children with different neoplasms].

The rate of HbF was studied in 123 children with different malignancies in order to assess its changes and relationship with other values of peripheral blood. The cases were distributed into 34 with acute lymphoblastic leukaemia (ALL), 19 with acute myelogenous leukaemia (AML), 23 cases of Hodgkin's disease (HD), 16 of non-Hodgkin lymphoma (NHL) and 31 of different solid tumors (ST). ALL and AML groups had the highest HbF rates (2.88 +/- 1.93% and 2.63 +/- 2.7%, respectively), followed by HD and NHL (1.89 +/- 1.09% and 1.81 +/- 1.68%, respectively), whereas the ST group showed the lowest values (1.32 +/- 1.74%). When comparing these figures with the findings in a group of adult leukaemia and lymphoma (1.6 +/- 0,7% and 1.2 +/- 0.5%, respectively), it was found that HbF was increased in the children to a higher extent. The analysis of the gamma G and gamma A chains of HbF, performed on 14 of the patients, showed in 7 cases a correlation similar to the newborn pattern, while this was similar to the adults in the remainders. These findings suggest that some factors intrinsic to the neoplasm might favour, in a different degree, the re-expression of HbF, which, in turn, would not necessarily mean a reversion to the foctal stages since the correlation of the gamma chains was similar to the adult pattern in 50% of the cases studied.

Adolescent↗
PubMed1989

[Professional role of the physician in health care].

The professional role of the doctor in health care was analyzed in terms of the peculiarities of the chilean social reality. Determining factors include tradition, the expectations of society and demands of health policies. Action fields and primary and delegated functions are identified. This may be important to help prevent the take over of some of these functions by other health professionals.

Chile↗
PubMed1988

Electric field distributions of waveguide arrays for local tumor hyperthermia.

Total electric field distributions in muscle and fat tissues, due to colinear rectangular waveguide arrays at 2.45 GHz and 915 MHz were calculated. The effect of phase difference between incident phases on the field pattern is shown. Phase adjustment is capable of furnishing control of either field-size or focused-field performance of the multi-element, direct-contact applicator. The tissue-applicator junction is analyzed by means of the Generalized Scattering Matrix (GSM) of the generalized 2-port discontinuity, assuming that the lossy homogeneous tissue is immersed in a large waveguide. This method provides an exact calculation of multimodal fields, as well as reflection and coupling coefficients in the apertures.

Electromagnetic Fields↗
PubMed1966

Clinical trial of a combination of lynestrenol and mestranol (Lyndiol) as an oral contraceptive agent.

Contraception with lynestrenol-mestranol (Lyndiol) was studied in 332 Mexican women during a period of two and one-half years. Side effects were minimal or transient. No pregnancies occurred in those who took the medication according to instructions. The women were followed with yearly pelvic examinations and Papanicolaou smears, serial endometrial biopsies and extensive studies of blood, liver and glandular function. Complete ophthalmological studies were done on 30 patients. No clinical or laboratory evidence of harmful effects could be demonstrated. Return to ovulation (using pregnanediol excretion and endometrial biopsies as parameters) occurred in all of 22 women studied in the first three post-treatment cycles. Eight posttreatment pregnancies and the resulting offspring were normal. The first post-treatment cycle, as with other oral contraceptives, was unpredictable and tended to be prolonged. It varied in length from 22 to 60 days.

Adolescent↗