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Biomedical subjects

G Pareja

Publications and source records attributed to G Pareja.

13 recordsLinked to original sources
PubMed1989

Measurement error in clinical perinatal data.

The error measurement of clinical perinatal variables obtained during the standardization and data-collection periods of a large prospective epidemiologic study is presented. The error is considerably larger during the data-collection period, particularly with regard to uterine height, birth weight, and blood pressure values. This information strongly supports the need to continuously supervise and monitor perinatal data collection systems, even after standardization.

Data Collection↗
PubMed1989

Biochemical changes associated with blood pressure reduction induced by calcium supplementation during pregnancy.

In a study population that comprised 34 normal black pregnant women, biochemical changes are compared between a group of women who received 1.5 gm of calcium supplementation a day and a group of women who received placebos. The blood pressure-lowering effect of calcium supplementation appears to involve a mechanism that relates parathyroid hormone and plasma renin activity. Other alterations in calcium and magnesium metabolism, as reflected by increased urinary calcium excretion and serum magnesium levels, may also contribute to this effect. Subgroups of study participants with initial (less than 26 weeks' gestation) low levels of serum calcium and plasma renin activity are the ones with the largest reductions in blood pressure. Whether these alterations can produce a reduction in the incidence of pregnancy-induced hypertension is the next question to be answered in this area.

Adolescent↗
PubMed1989

[Evaluation of the reliability of anthropometric measures].

As part of the Early Malnutrition and Its Effects on Youth Project, a study of the reliability of anthropometric measures was carried out through the re-measurement of 226 adolescents of the rural area of Guatemala. In all anthropometric variables, the intra-measure coefficients of reliability were higher than 0.96 and the inter-measure coefficients of reliability higher than 0.91. A significant effect of the measure was found, suggesting the existence of systematic differences among measures. This information will permit corrections by measure effect in the analysis of data. The effect of different grades of "data editing" and "validity, reliability and agreement check", of measures was evaluated. The conclusion was that even though the persons in charge of measurements were trained and supervised, the deletion of values outside ranks did not result in an appreciable decrease of the technical error of measurement. As expected, data editing and validity carried out through the comparison of two measurements taken from each subject and eliminating those whose differences were classified as error according to statistical criteria, decreased the technical error of measurement, in most of the variables measured. Nevertheless, with the exception of one of the variables, this decrease was not marked. This indicates that the technical error of measurement obtained from all the subjects, many of whom were not re-measured, was within acceptable ranks. Results of the study demonstrate the importance of including re-measurement of a certain percentage of subjects when designing anthropometric studies. This will allow evaluation of the reliability of measurements, identification of bias due to measurements, and their correction.

Adolescent↗
PubMed1989

[Acute and persistent diarrheal disease and its nutritional consequences in Guatemalan infants].

For the purpose of better understanding the epidemiology of acute and persistent diarrhea, 130 infants of a marginal urban area in Guatemala City were studied. The subjects were kept under surveillance by weekly home visits, for periods that varied from three to nine months. The diarrhea episodes were detected and microbiological studies were done in fecal material. Additionally, the children were weighed and measured to determine their nutritional status. The infants suffered, on the average, 5.2 episodes per child annually; 9.4% of all the episodes lasted at least two weeks. The children who were less than six months old had more episodes of persistent diarrhea (0.052/child-month) than the older ones (0.017/child-month), with previous diarrhea morbidity and number of infecting enteropathogens being important factors. Furthermore, a child who had already suffered an episode of persistent diarrhea had a higher probability (relative risk = 2.2) of developing an additional one. Adherent E. coli, Cryptosporidium, toxigenic E. coli and Campylobacter jejuni are the pathogens more commonly associated with persistent diarrhea. Diarrheal illnesses have a deleterious effect on nutritional status, especially persistent episodes, which interfere with gain in weight and length of the children.

Acute Disease↗
PubMed1988

Perinatal data reliability in a large teaching obstetric unit.

In this inter-rater agreement study of antenatal and neonatal variables collected in a large teaching obstetric unit, information routinely collected by hospital staff was compared with that collected by a specially trained physician and a social worker. Agreement between the two sources of data was evaluated using kappa statistics and intraclass correlation coefficients. Excellent agreement was observed for some variables such as maternal and newborn anthropometric measures, and previous birthweight, but there was poor agreement for others such as indicators of physical activity, work during pregnancy and blood pressure measures. Some of the limitations are due to problems in phrasing questions, patients' recall, interviewer bias and abstracting data. We recommend that epidemiological studies should always include a reliability component, proper standardization of personnel and instruments and include, when published, validity data and examples of questions used.

Adult↗
PubMed1988

Breast milk anti-Escherichia coli heat-labile toxin IgA antibodies protect against toxin-induced infantile diarrhea.

A prospective study to assess whether milk IgA antibodies against Escherichia coli heat labile-toxin protect breast-fed children against labile toxin-induced gastroenteritis was carried out among infants of a marginal urban area in Guatemala. One hundred and thirty children were kept under surveillance for diarrhea by periodic home visits. Stool specimens were collected from each child routinely every 2-3 weeks and during diarrheal episodes, to study the excretion of labile toxin-producing Escherichia coli. Milk samples from the children's mothers were obtained concomitantly with the fecal specimens of the infants to be analyzed for anti-labile toxin antibodies. Twenty infections by heat-labile toxin-producing Escherichia coli as a sole agent were documented among breast-fed infants. Nine of these infections resulted in gastroenteritis, while the remaining 11 were asymptomatic. At the time of infection children who became sick were ingesting breast milk with significantly (p = 0.028) lower titers of antilabile toxin IgA than those who remained healthy. Only one of the 8 infected children receiving breast milk with high titers (greater than or equal to 256) of anti labile toxin IgA developed diarrhea, compared to 8 of the 12 subjects being fed milk with low titers (less than or equal to 64) (p = 0.025). This is the first report documenting protection by IgA antibodies in milk against labile toxin-induced gastroenteritis in infected breast-fed infants.

Bacterial Toxins↗
PubMed1988

Infection and diarrhea caused by Cryptosporidium sp. among Guatemalan infants.

During July 1985 to June 1986, fecal excretion of Cryptosporidium oocysts was determined prospectively in a cohort of 130 infants, aged 0 to 11 months, living in a marginal urban area of Guatemala City, Guatemala. A total of 1,280 stool specimens were examined; 158 of them were collected during episodes of diarrhea, and 1,122 were collected during symptom-free periods, every 2 to 3 weeks, from every child. Of the children, 20 (15.4%) excreted Cryptosporidium oocysts during the observation period. Of the diarrheal episodes, 13 (8.3%) were associated with Cryptosporidium sp. Of the control specimens, seven (0.6%) were positive for oocysts. Most of the infections were documented during the months of February to May, at the end of the dry season. Cryptosporidium infections are very common among Guatemalan infants and are an important cause of diarrhea and weight loss. The introduction of liquid or solid foods in the diets of the children, the presence of domestic animals (dogs, cats, or poultry), and the absence of toilet facilities in the house seem to be important risk factors for infection; also, deficient nutritional status may predispose the infected child to Cryptosporidium-associated illness.

Age Factors↗
PubMed1987

The treatment of stage III carcinoma of the uterine cervix with telecobalt irradiation.

This is a retrospective analysis of 148 patients with histologically proven carcinoma of the cervix, stage III, treated with irradiation. All patients received external irradiation with cobalt 60 followed by intracavitary radium application. The median age was 55 years. Squamous cell carcinoma was found in 96.5% of the cases. The 8-year actuarial survival rate was 41%. Bilateral parametrial invasion proved to be a strong prognostic factor. Patients with unilateral disease had a survival rate of 43% whereas in those with bilateral involvement it was only 15% (P less than 0.005). The total pelvic failure rate was 29.5%. The overall incidence of distant metastasis was 11%. The complication rate (minor and major complications) was high, with vaginal stenosis (22.5%), proctitis (21.5%), cystitis (13.5%), and fistulae (4%) occurring in 33, 32, 20, and 6 patients, respectively. New treatment modalities are urgently needed for advanced carcinoma of the cervix. Bilateral parametrial involvement is an unfavorable prognostic factor and this should be kept in mind when designing new protocols.

Adult↗
PubMed1987

Calcium supplementation reduces blood pressure during pregnancy: results of a randomized controlled clinical trial.

Fifty-two healthy pregnant women were enrolled in a double-blind, randomized, controlled clinical trial. After the 26th week of gestation, the women were given either 1.5 g of elemental calcium per day or a placebo. Subjects in the calcium group, after adjustment for race and initial blood pressure (BP), had a term mean systolic and diastolic BP value of 4-5 mmHg lower than those in the placebo group (P less than .05). The incidence of pregnancy-induced hypertension was 11.1% in the placebo group and 4.0% in the calcium group, a nonsignificant difference. Combining these values with previous data, we found a dose-effect relationship between calcium intake and BP reduction during the third trimester of pregnancy. Further research should be directed at understanding the mechanism of this effect and trying to demonstrate a reduction in pregnancy-induced hypertension with calcium supplementation in a larger population.

Blood Pressure↗
PubMed1982

Altitude and infant growth in Bolivia: a longitudinal study.

The growth of 79 healthy, well-nourished lowland (400 M) and highland (3600 M) Bolivian infants was analyzed in a longitudinal study through the first postnatal year. Compared to low altitude infants, the high altitude infants were found, by analysis of covariance controlling for size at the previous exam, to be significantly shorter at birth, 1 and 6 months, while they were significantly lighter only at birth and 1 year. Recumbent length gain was slower in the high altitude infants in the early months of life, while weight gain did not differ between altitudes. The observed lower weights at high altitude throughout the first year appear to be due to a persistence of lower weights seen at birth and not to postnatal growth retardation. Significantly greater triceps and subscapular skinfold thickness measurements were found in the highland group, despite their smaller length and weight. The possible causes and implications of the greater fat accumulation in the highland infants are discussed.

Altitude↗
PubMedDate not supplied

Epidemiology of acute respiratory tract infections among Guatemalan ambulatory preschool children.

Acute respiratory tract infections (ARI) were studied during a 2-year period in 521 preschool children living in a marginal area of Guatemala City. There were 3,646 episodes of ARI detected during 26,329 child-weeks at risk, for an incidence of 14 per 100 child-weeks or 7.2 episodes per child per year. The median duration of ARI episodes was 11 days. The highest incidence of ARI was observed in children 6-23 months old. Boys had more respiratory tract illnesses than did girls; the presence of a cigarette smoker in the household was associated with higher morbidity. Acute lower respiratory tract illnesses (ALRI) were more common among younger infants 0-5 months old, with nutritional status having no apparent effect. Parental formal education and crowding in households were found to be directly related to the incidence of ALRI. In general, ARI morbidity interfered with appropriate physical growth.

Acute Disease↗