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Biomedical subjects

R Mercado

Publications and source records attributed to R Mercado.

At least 55 records · Page 3Linked to original sources
PubMedDate not supplied

[Seasonal variation of intestinal protozoa infections in outpatients of the north section of Santiago, Chile. 1995-1996].

Formalin preserved fecal samples from 6,058 and 5,863 outpatients were examined for intestinal parasites during 1995 and 1996 respectively. Prevalence rates of infections by intestinal protozoa in both years were similar. By age group (0-9, 10-19 and > 20 years old) Blastocystis hominis was observed in 18.6-19.3, 37.0-31.1 and 25.3-25.4% in 1995-1996 respectively. Prevalence of Giardia intestinalis infections decreased from 16.6-17.4% in the 0-9 year-old children group to 4.1-4.5% in patients over 20 years. Overall percentages of infection by Entamoeba histolytica varied between 4.2 and 10.9. Rates of infections by G. intestinalis, E. histolytica, and Entamoeba coli observed during rainy-cold months (april-september) of the year versus drywarmy period (october-march) were the same. On the contrary, more cases of B. hominis infection 25.8% versus 18.2% (this difference being statistically significant, p > 0.001) were observed during rainy-cold months of the year.

Adolescent↗
PubMedDate not supplied

[Environmental contamination with Toxocara sp. eggs in public squares and parks from Santiago, Chile, 1999].

Most of cases of visceral larva migrans syndrome are caused by Toxocara canis larvae. Man acquires the infection by accidental ingestion of ripe eggs of the helminth. In order to find out the frequency of the presence of Toxocara sp. eggs in dog fecal specimens from public places of Santiago city in 1999 july-september a study was carried out in 84 squares and 12 parks from 32 counties. Three fecal samples were collected in each of these places, making a total of 288. Each sample was processed according to a modified Telemann method and three smears of each were microscopically examined. Toxocara sp. eggs were found in 39 (13.5%) fecal specimens. In 28/84 (33.3%) squares and in 8/12 (66.7%) parks these eggs were detected. These results make necessary the control of dogs and cats populations with the aim of reduce the presence of animals without responsible owners. It should be advisable to prevent dogs and cats defecation in public areas grounds, trying to exclude these animals from recreation areas.

Animals↗
PubMedDate not supplied

[Epidemiological and diagnostic aspects of human Cryptosporidiosis in Chile].

Cryptosporidium sp. infections have been reported in different Chilean localities, both in healthy individuals and immunocompromised patients. Among the first, hospitalized and ambulatory children less than 3 years old are the age group more affected reaching frequencies from 3.1 up to 19.3%. In pre-school children, school children and adults the prevalence rates have been 1.1, 0.2 and 0.3% respectively. According to the epidemiological studies carried out, the routine laboratory diagnosis of this parasitosis should be emphasized in the parasitological stool examinations in children under 3 years of age, and selectively in the older ones.

Adult↗
PubMedDate not supplied

[Absorption of human serum antibodies against Toxoplasma gondii using Tachyzoites from the RH strain].

Absorption experiments to determine the number of T. gondii tachyzoites to extract the anti-Toxoplasma antibodies present in the human serum were carried out. The antibodies titer from each serum (n = 4) was determined by means of the Sabin-Feldman test (dye test). Ten millions of tachyzoites were sufficient to absorb the antibodies from sera presenting titer 1:16, 1:64 and 1:256. On the other side, the absorption of a 1:512 positive serum with 10 x 10(6) T. gondii decreased the titer to 1:64 and the dye test became negative when using 50 x 10(6) tachyzoites.

Animals↗
PubMedDate not supplied

[Blastocystis hominis: frequency of infection in ambulatory patients from the northern section of Santiago, Chile].

In July 1989-July 1990 period, a coproparasitological study of 6,162 ambulatory patients from the northern section of Santiago, was undertaken. Out of the total number of the studied individual, 88.6% were children, (51.4% females and 48.6% males). The global frequency of infection by B. hominis was 30.4%. In relation to age. Blastocystis hominis was found in: 13.1% of the group of children (1 month-2 years); 34.1% of the pre-school children, 45.4% in the school-children and 43.0% in the adults. B. hominis was frequently detected in association with other parasites and/or commensals, and observed alone in the 6.0% of the studied patients.

Adolescent↗
PubMedDate not supplied

[Isolation of Cryptosporidium sp. oocysts from human fecal samples].

Experiments using two sequential discontinuous sucrose gradients, performed with 12%, 18%, 21% and 24% solutions, for the isolation of Cryptosporidium sp. oocysts from human fecal samples were undertaken. The sucrose gradients were centrifuged at 4000 rpm during 20 min. at 10 degrees C or room temperature. After that, 3 bands were observed. Oocysts were recovered mainly from the second band (75.5% after the first gradient, and 44.4% in the next). The two sequential discontinuous sucrose gradients would permit an efficient isolation of Cryptosporidium sp. oocysts from human fecal samples.

Animals↗
PubMedDate not supplied

[Incidence of infection by intestinal parasites among school children in Santiago, Chile, 1988-1989].

In December 1988-February 1989 period, a survey on enteroparasitic infections in children (mean age 8.7 years; males 54.4% and females 45.6%) from five schools located in Santiago, Chile, was undertaken. To each of these individuals, three samples were obtained in order to perform in them the following examinations: co-proparasitological study, modified Ziehl-Neelsen staining for detecting Cryptosporidium sp. and cellulose adhesive test for Enterobius vermicularis. Parasitic elements were found in the following percentages: Blastocystis hominis 51.8, Enterobius vermicularis 39.9, Giardia lamblia 32.1, Entamoeba histolytica 7.8, Hymenolepis nana 2.1 and Ascaris lumbricoides 0.4, Cryptosporidium sp. were not observed. The present study would be demonstrating that enteroparasites maintain their endemic condition among school children from Santiago, including B. hominis which had not been searched previously.

Adolescent↗
PubMedDate not supplied

[Detection of immunoreactive peptides of Fasciola hepatica, with sera from infected subjects, by enzyme immunoelectrotransfer].

In order to observe the immunoreactive peptides in a crude extract of adult Fasciola hepatica specimens, proteins were separated by 10% sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and transferred to nitrocellulose paper. Next, sera from 14 human cases of F. hepatica infection, parasitologically confirmed, which presented high titers of specific antibodies against F. hepatica detected by ELISA, were reacted with the blotted peptides and immunodetected by an anti-human IgG conjugated with horse-radish peroxidase. SDS-PAGE showed at least 18 bands ranging 96 to 14 Kd. Groups of peptides weighing 94-66 Kd, 43-36 Kd and 35-14 Kd reacted with serum antibodies of 12 fascioliasis patients. In the remaining two cases, reactive peptides were not clearly observed. The 94-66 Kd components were immunoreactive with 12 out of the 14 serum samples. On the other hand, 43-36 Kd peptides reacted with 4 of the 14 sera and only 3 out of the 14 sera of infected individuals showed reaction with 30-14 Kd. F. hepatica infection induces in humans diverse antibody responses, being 94-66 Kd bands the most immunoreactive peptides and would be potential serodiagnostic antigens.

Adolescent↗
PubMedDate not supplied

[Asymptomatic cryptosporidiosis in an infant].

A two year-old male who presented lack of appetite, mild coughing and one episode of vomiting was assisted in a pediatrics outpatient clinic. The parasitological examination of three stool samples of the patient revealed the presence of Cryptosporidium parvum oocysts. Fecal parasitological examination of his mother and a one year-old sister showed oocysts of the same protozoon in this last patient, who was asymptomatic. With no pharmacological treatment, parasitological stool examination, performed one month later on the two children, resulted negative, being the boy without any symptom.

Animals↗