Biomedical subjects

R Mercado

Publications and source records attributed to R Mercado.

60 records · Page 4Linked to original sources

PubMedDate not supplied

[Epidemiology of Chagas' disease in Chile. Serological follow-up of 1,906 inhabitants from an endemic rural area, IV Region, 1991-1993].

The IV Region (29 degrees 30'-32 degrees 13' south lat.) is located in the center of the geographical area of distribution of Chagas' disease in Chile. Triatoma infestans is the main and almost exclusive vector of Trypanosoma cruzi in this country. The mean prevalence rate of T. cruzi human infection in urban and periurban sections of IV Region is 24.7%. To assess the impact of anti-T. infestans activities, by means of health education and sprayings of dwellings with insecticides, carried out in the IV Region since 1980, during January-February (summer) a serological follow-up to residents from 46 rural chagasic localities was performed. An indirect hemagglutination test and an indirect immunofluorescence test were done to each of the surveyed persons. In 1991, 303 (15.9%) out of 1,906 examined people resulted serologically positive. In 1992, previous discarding the positive individuals found in 1991, 1,334 persons were examined resulting positive 9 (0.7%). In 1993, 1,398 persons were surveyed and 26 (1.9%) were positive. It is noteworthy that none of these 35 positive persons had been surveyed in 1991, being difficult to assert if any was positive before. Two infants, daughters of positive mothers, serologically positive at the beginning, changed to negative in the following survey, indicating that it was a passive transfer of maternal specific antibodies. According to the results of this study, it is concluded that dwelling spraying with persistent-activity insecticides against T. infestans and health education are good tools in the control of T. cruzi human infection, particularly when the involved community participates.

Adolescent↗

PubMedDate not supplied

[A modified Strout test, used as a probe for the diagnosis of transplacental Chagas disease. I. Collection and preservation of the newborn's umbilical cord blood].

Two umbilical cord (UC) blood samples are routinarily taken from each newborn (NB) at the University of Chile Maternity Hospital, to determine blood grouping and for detecting syphilis infection respectively. In august-september 1993, an additional UC blood sample was collected from each of 116 NB (with volumes of whole blood ranging 2.7 - 24.5 ml and a mean of 13.5 ml). In order to determine the persistence of the mobility of Trypanosoma cruzi in blood samples stored at three different temperatures (-2 to -4 degrees C, 4 to 6 degrees C and environmental temperature from 16 to 23 degrees C), two experiments were performed: 1) In three centrifuge microtubes mouse blood (C3H strain) abundant T. cruzi trypomastigotes Tulahuen strain were put. 2) In an other similar number of microtubes, with the same concentration of parasites, human serum from UC was added. During the first 12 h in all the samples trypomastigotes with very active mobility were observed. At 72 h mobility persisted in samples with temperature between 4 and 6 degrees C and between 16 and 23 degrees C. Whereas in the samples maintained at -2 to -4 degrees C with parasites in blood plus serum, an important decrease of T. cruzi mobility was observed. The results of this study suggest that UC blood samples could be collected and maintained between 4 and 6 degrees C or at room temperature up to 48 h to be processed by the modified Strout concentration method (MSCM).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMedDate not supplied

Radiofrequency field surveys in hospitals.

The authors surveyed levels of radiofrequency (RF) fields in the frequency range 0.1-1,000 MHz in four hospitals in the Philadelphia area, to obtain background information related to the possible interference of radiofrequency fields with medical equipment. Two large center-city hospitals, a regional county hospital, and two suburban hospitals were surveyed. Measurements were made at six to 12 sites in each hospital, in each of the three frequency bands. More limited additional measurements were conducted in a fifth hospital as well. Sites were selected to include areas where strong RF signals from transmitting antennas might be expected to be present (e.g., locations close to windows in upper stories of buildings near paging antennas) as well as other representative sites in the hospital. The median RF field strengths were quite low (0.1-0.5 V/m), but at specific locations the RF signals from broadcast sources exceeded 1 V/m. Much stronger fields were recorded close to electrosurgical units and hand-held transmitters (cellular telephones and UHF transceivers).

Electromagnetic Fields↗

PubMedDate not supplied

[Taenia sp and other intestinal cestode infections in individuals from public outpatient clinics and hospitals from the northern section of Santiago, Chile (1985-1994)].

During 1985-1994 period, 70,642 parasitological stool examinations were performed. The exam was made to each patient which presenting gastrointestinal symptoms or nutritional problems, specially in children. 59,960 out of the 70,642 examinations corresponded to 1 month--15 years old children, 4,280 to 16-30 years old individuals and 6.402 to up to 30 years old adults. The infection rates (x 100,000) were: Taenia sp., 86; Hymenolepis nana, 1,165; Diphyllobotrium sp., 4 and Hymenolepis diminuta, 1. In this period, 11 cases of infection by Taenia saginata were detected, and none Taenia sodium infection. Although infections rates by intestinal cesdodes were higher in males than females, in the Taenia sp. infection the difference was not statistical significative. Médico-veterinary control of animals slaughtered in abbatoirs and the improvement of sanitary conditions in the last two decades have contributed to the control of most of human intestinal cestodiases.

Adolescent↗

PubMedDate not supplied

[Various epidemiological aspects of Enterobius vermicularis infection inpatients served at public outpatient clinics and hospitals from the northern section of Santiago, Chile, 1995].

During 1995, we examined 2,666 Graham's tests (five perianal swabs with adhesive cellulose tape) prescribed to ambulatory patients attended in 14 public outpatient clinics and four hospitals from the north section of Santiago. The infection rates found by age groups were the following: 6.1% in infants (< 2 years old), 20.9% in pre-schoolchildren (2 < 6 years old), 35.2% in elementary schoolchildren (6 < 15 years old) and 15.2% in adults (> 15 years old). Similar percentages of E. vermicularis infections were observed in females and males patients. Frequency of infection in each month of the year varied between 17.4 and 26.8%, with no seasonal variation. This study and previous surveys are stressing that E. vermicularis is the most frequent helminthic agent found in Chile, specially in elementary school children.

Adolescent↗

PubMedDate not supplied

[Human infection by intestinal protozoa and helminths in Calbuco County, X Region, Chile, 1997].

By the performance of parasitological examination of one fecal sample per individual, a total of 256 persons from a rural county in the X Region (41 degrees 50 minutes South lat., 73 degrees 05 minutes West long.) were studied. The general rates of infection by intestinal parasite and/or commensal protozoa and helminths found were: Giardia intestinalis 14.1%, Entamoeba histolytica 11.7%, Blastocystis hominis 36.0%, Entamoeba coli 9.8%, Endolimax nana 16.4%, Iodamoeba buetschlii 1.2%, Chilomastix mesnili 0.8%, Ascaris lumbricoides 13.7% and Trichuris trichiura 9.8%. The prevalence rates of intestinal infection led us to conclude that environmental conditions favorable for its transmission remain and show that intestinal parasitoses are still a public health problem in this region, affecting mostly children.

Adolescent↗