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Biomedical subjects

C E Castillo

Publications and source records attributed to C E Castillo.

10 recordsLinked to original sources
PubMed2006

Use of the pupal/demographic-survey technique to identify the epidemiologically important types of containers producing Aedes aegypti (L.) in a dengue-endemic area of Venezuela.

As dengue continues to emerge as a major public-health problem world-wide, efforts to control the dengue vector Aedes aegypti must become more effective and efficient. Results from larval and pupal surveys applied in Venezuela illustrate the uniqueness of the information gained from pupal surveys; information that is lost when traditional Stegomyia indices are calculated. As most Ae. aegypti pupae will emerge to become adults, controlling the containers that produce the most pupae could have the greatest impact on the adult population. Pupal-survey results in Venezuela showed that large (150- to 200-litre) water drums produce the greatest number of pupae throughout the year. In the rainy season, approximately 70% of all pupae are found in these drums or in tyres, buckets and tanks. Over 80% of pupae in the dry season are found in drums and tanks alone. By targeting only those domestic breeding containers that produce the greatest number of pupae, control efforts may be streamlined to have the greatest impact on reducing the local adult Ae. aegypti population.

Aedes↗
PubMed2005

Toxoplasma gondii infections in chickens from Venezuela: isolation, tissue distribution, and molecular characterization.

The prevalence of Toxoplasma gondii, in free-ranging chickens is a good indicator of the prevalence of T. gondii oocysts in the soil because chickens feed from the ground. The prevalence of T. gondii in 46 free-range chickens (Gallus domesticus) from Venezuela was determined. Antibodies to T. gondii were assayed by the modified agglutination test (MAT). Antibodies were found in 16 (32%) chickens with titers of 1:5 in 1, 1:10 in 2, 1:40 in 2, 1:80 in 2, 1:160 in 2, 1:320 in 3, 1: 640 in 2, and 1:1,280 or higher in 2. Hearts, pectoral muscles, and brains of 13 chickens with MAT titers of 1:40 or more were bioassayed individually in mice. Tissues of each of 3 chickens with titers of 1:5 or 1:10 were pooled and bioassayed in mice. Tissues from the remaining 30 seronegative chickens were pooled and fed to 1 T. gondii-free cat. Feces of the cat were examined for oocysts; it did not shed oocysts. Toxoplasma gondii was isolated from 12 of 13 chickens with MAT titers of 1:40 or more. Toxoplasma gondii was isolated from pooled tissues of 1 of 2 chickens with titers of 1:10. Eight of these 13 isolates were virulent for mice. Genotyping of 13 of these isolates using the SAG2 locus indicated that 10 were type III, and 3 were type II. Phenotypically and genetically these isolates were different from T. gondii isolates from North America and Brazil. This is the first report of isolation of T. gondii from chickens from Venezuela.

Agglutination Tests↗
PubMed1995

Growth hormone-binding protein in human lymph.

The high affinity GH-binding protein (GHBP) is a soluble circulating ectodomain of the GH receptor (GHR). In humans, it is thought to be released from the plasma membrane-bound GHR by proteolysis at or near the transmembrane domain. GHBP modulates GH action by 1) intravascular complex formation, and 2) competing with the GHR for ligand in tissues (interstitial complex formation). Little is known about the tissue source(s) of GHBP, the local regulation of GHBP generation, or its concentration in the interstitium. To begin addressing these questions, we studied GHBP levels in peripheral lymph, whose composition approximates that of interstitial fluid. Lymph was collected in 13 healthy adult men from cannulated lymphatic vessels in the calf. Venous and arterial blood samples were collected from the femoral vein and radial artery contemporaneously with lymph collection. Potential GHBP production by endothelial or blood cells was assessed by examining conditioned medium from in vitro cell cultures. GHBP activity was measured by standardized GH binding/column chromatography assay. GHBP was consistently and significantly lower in lymph (mean +/- SD, 4.6 +/- 1.2% GH bound/200 microL) than in venous (14.1 +/- 3.0%) or arterial (14.9 +/- 3.6%) plasma. Conditioned medium from endothelial or blood cell cultures did not contain detectable GHBP. We conclude that the level of GHBP in peripheral lymph is substantially lower than that in the peripheral circulation, and that components of the vasculature are not important sources of GHBP. These findings suggests that 1) the main tissue sources of GHBP in man are the central organs (especially liver); and 2) transcapillary diffusion of GHBP into the interstitial space is restricted.

Adult↗
PubMed1992

[Posthumous homage of the Venezuelan Society for the History of Medicine to Dr. Tulio Villalobos Capriles].

Testimonial to doctor Tulio Villalobos Capriles (18-10-22 al 03-06-91), the Venezuelan Society of the History of Medicine former President (1987-89). After his graduation when he was 23 years old (S.A. Dominici Promotion), he developed a very important work on Hematology in the Central University Medical School and in the "Carlos J. Bello" Hospital (Venezuelan Red Cross). He made more than 120 publications in several national and foreign reviews. Remembering Ovidio, the author says "Supremum vale, Tulio Villalobos".

Hematology↗
PubMed1991

Fasting inhibits insulin-mediated glycolysis and anaplerosis in human skeletal muscle.

Euglycemic (approximately 5.5 mM) hyperinsulinemic (60 mU.m-2.min-1) clamps were performed for 2 h after a 10-h fast and after a prolonged (72-h) fast. Biopsies were obtained from the quadriceps femoris muscle before and after each clamp. The rate of whole body glucose disposal was approximately 50% lower during the clamp after the 72-h fast (P less than or equal to 0.001). The increase in carbohydrate (CHO) oxidation (which is proportional to glycolysis) during the clamp after the 10-h fast (to 13.8 +/- 1.5 mumol.kg fat free mass-1.min-1) was completely abolished during the clamp after the 72-h fast (1.7 +/- 0.6; P less than or equal to 0.001). During the clamp after the 10-h fast, postphosphofructokinase (PFK) intermediates and malate in muscle increased, whereas glutamate decreased (P less than or equal to 0.05-0.001 vs. basal) and citrate did not change. During the clamp after the 72-h fast, there were no significant changes in post-PFK intermediates or glutamate (P greater than 0.05 vs. basal), but there was a decrease in citrate (P less than or equal to 0.01 vs. basal). Euglycemic hyperinsulinemia increased glycogen synthase fractional activity in muscle under both conditions but to a greater extent after the 72-h fast (P less than or equal to 0.01). It is concluded that insulin (after 10-h fast) increases glycolytic flux and the content of malate in muscle, which is probably due to increased anaplerosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Peripheral lymphatic cannulation for physiological analysis of interstitial fluid compartment in humans.

Analysis of peripheral interstitial concentrations of hormones or substrates in humans has undoubtedly been hampered by the difficulty in performing retrograde peripheral lymphatic cannulation and obtaining adequate flow rates of lymph. We now describe a technique for direct continuous sampling of peripheral lymph. A lymphatic vessel was cannulated in the lower legs of 14 males, and lymph was collected for 24-48 h. Adequate quantities of lymph were obtained basally and during physiological manipulations to make collections at 15-min intervals. Flow rates averaged 1.84 ml/h and ranged from 0.34 to 4.96 ml/h. We conclude that peripheral lymphatic vessels can be cannulated and flow rates are sufficient to measure interstitial concentration of hormones or substrates both at steady state and dynamically in adult humans.

Adult↗