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Biomedical subjects

H A Perez

Publications and source records attributed to H A Perez.

15 recordsLinked to original sources
PubMed1995

Plasmodium vivax: detection of blood parasites using fluorochrome labelled monoclonal antibodies.

A monoclonal antibody (MoAb) 2C6111 specific for Plasmodium vivax erythrocytic stages was shown to detect parasitized erythrocytes in blood samples collected in the field. This MoAb binds to the mature trophozoite, schizont and gametes of P. vivax and upon examination of 43 wild isolates no evidence of polymorphism was found. To search for P. vivax parasites in human blood a MoAb immunofluorescent test (MoAb-IFT) was developed. The assay is based on the ability of fluorescein isothiocyanate labelled MoAb 2C6111 to combine with parasitized erythrocytes on thin blood smears. A preliminary field trial was carried out in Venezuela to determine the usefulness of MoAb-IFT for the specific diagnosis of P. vivax malaria. Blood samples collected from malarious and non-malarious individuals were examined both by standard microscopy of Giemsa stained thick blood smears (G-TS) and MoAb-IFT. The latter was specific and gave a 100% correlation with G-TS. Sensitivity was close to that usually achieved with Giemsa stained blood films.

Animals↗
PubMed1990

Malaria in the Amazon. Prevalence of Plasmodium falciparum antibodies in Amerindians inhabiting the Venezuelan Amazon.

The acquisition of antibodies to Plasmodium falciparum in various age groups was studied in 511 Amerindians inhabiting the north of the Venezuelan Amazon. The overall prevalence by ELISA was 91.2% and antibodies were acquired early in life. Seropositivity was 69.6% in the group aged two to five years and reached 86% at 10 years of age; 96.9% of the adults aged 31-40 years exhibited high ELISA values to P. falciparum. The high prevalence of malaria antibodies among Amazonians, from early on in life, reflects the high level of malaria transmission in that part of the world.

Adult↗
PubMed1983

Morphologic alterations of rat Leydig cells induced by ethanol.

Ultrastructural morphometric studies were employed to compare the morphology of Leydig cells found in the testes of rats fed ethanol, accounting for 36% of total calories for 6 weeks, and those found in the testes of rats isocalorically fed a diet in which ethanol was isocalorically replaced with dextrimaltose. The testes of alcohol-fed rats weighed significantly less (p less than 0.01) than those of the isocaloric controls. Moreover, plasma testosterone in the alcohol-fed animals was reduced (p less than 0.01), as compared to the controls. Morphologically, two main differences were encountered between the Leydig cells of alcohol-fed animals and those of the isocalorically-fed controls. These were: (1) an increase in the number of elongated and cup-shaped mitochondria; and (2) an increase in cytoplasmic protrusions in the form of pseudopods. Using morphometric techniques, the Leydig cells of alcohol-fed animals were smaller (p less than 0.05), had less cytoplasm (p less than 0.05), larger mitochondria (p less than 0.01), and less smooth endoplasmic reticulum (p less than 0.05) than did those of the isocaloric controls. These morphologic characteristics of Leydig cells of alcohol-fed animals are similar to those reported to occur in the liver and suggest that the biochemical mechanisms responsible for alcohol-induced cellular injury are similar in the testes and the liver.

Animals↗
PubMed1969

[Asthenopia].

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Adolescent↗
PubMedDate not supplied

[The immunoenzymatic assay (ELISA) in the serodiagnosis of Plasmodium vivax].

ELISA was evaluated for the serodiagnosis of Plasmodium vivax using homologous antigen. This was a crude fraction obtained after detergent (NP-40) lysis of human parasitized red blood cells. Antibodies of the classes IgM, IgG, IgA were determined in a pool of eleven sera from patients with P. vivax malaria. The protein A was introduced as secondary probe to screen P. vivax antibodies in 30 sera of patients harbouring a first episode of P. vivax malaria. There was a correlation of 93% with the parasitological diagnosis and the test resulted specific and reproducible.

Animals↗