PubMed Health⌕ Search

Biomedical subjects

L Mata

Publications and source records attributed to L Mata.

At least 55 records · Page 3Linked to original sources
PubMed1985

Low endemicity and low pathogenicity of rotaviruses among rural children in Costa Rica.

Rotaviruses were prospectively studied in 51 rural Costa Rican children from birth to two years. Samples of feces were collected weekly over a 33-month period. Rotavirus was detected in 45 (1.04%) of 4,317 fecal specimens; 39 infections were documented (an incidence of 0.5 infection per child-year), only five of which were associated with diarrhea (a pathogenicity of 12.8%). Secretory antibody in fecal extracts, detected in six of 39 infections, was short lived and did not protect against reinfection. Serum antibody was present in 69.6% of two-year-old children, but was not detected in 18.8% with documented infections. On the other hand, serum antibody was present in six of 14 children in whom rotavirus was not detected, thus increasing the overall incidence to 0.6 infection per child-year. The combination of prolonged breast-feeding, exposure to a lower infecting dose (compared with urban children), and a higher standard of hygiene than expected may explain the low incidence and low pathogenicity of rotavirus among these rural children.

Age Factors↗
PubMed1985

Collagen and the proliferation and differentiation of rat ventral prostate epithelial cells.

The purpose of this study was to determine if a cause-and-effect relationship exists between androgen-induced changes in collagen and epithelial cell proliferation and/or differentiation in rat ventral prostate. Analyses of the temporal relationship between dihydrotestosterone (DHT)-induced changes in the synthesis and levels of collagen in the regressed ventral prostates of adult castrates demonstrated that, during the first 7 days of restoration of prostatic growth, androgen increased the synthesis as well as the degradation of collagen. Cis-hydroxyproline (CHP) treatment (2-200 mg/kg) during the first 7 days of androgen-stimulated prostatic growth, combined with maintenance of animals on a proline-free diet, produced a dose-dependent reduction in prostate weight and DNA content to a maximum of 50%. The epithelium was characterized by numerous disorganized layers of irregularly shaped and tightly packed cells, many of which had no contact with the basal lamina. There was a loss of epithelial lamina lucida and the development of a ragged lamina densa. Cis-hydroxyproline effects were reversible in that, following cessation of CHP treatment, the perturbed morphology, DNA content, and organ weight returned to the range of DHT-treated controls. Collagenous components seem to be important in supporting the normal androgen-dependent proliferation and differentiation of prostatic epithelial cells.

Animals↗
PubMed1985

Cryptosporidiosis in Venezuelan children with acute diarrhea.

Thirteen of 120 Venezuelan children with acute diarrhea were found to be excreting Cryptosporidium oocysts in their stools. This confirms that Cryptosporidium can infect immunocompetent children, and the relatively high frequency found suggests that this protozoan may be an important cause of diarrhea in Venezuela.

Acute Disease↗
PubMed1985

[ABO and Rh blood groups and serum proteins in an Amerindian population of Matambú, Costa Rica].

Genetic structure of the population of Matambú, Costa Rica, was investigated using 6 genetic markers: ABO and Rh blood groups, and 4 serum proteins: albumin, ceruloplasmin, haptoglobin and transferrin. All the individuals were Rh+ and the I degrees allele had a high frequency (0.89). There are 4 polymorphic alleles in ceruloplasmin, including a possible new variant (3.8%). Transferrin Dchi had a remarkably high frequency (0.11). These results indicate that this group is of Amerindian origin although there are Caucasic and Negroid genes present. The genetic constitution of Matambú differs from that of the other Amerindian groups such as the Guaymí, from Chibcha stock, which supports the hypothesis of a Mesoamerican origin.

ABO Blood-Group System↗
PubMed1984

Cryptosporidiosis in children from some highland Costa Rican rural and urban areas.

This report summarizes both a prospective study of diarrhea in cohorts of rural children in their natural ecosystem, and a vertical study of diarrheic urban children attending a hospital emergency service. Cryptosporidium oocysts were found in feces of 4.3% of the cases, while all controls were negative. No infection occurred in the first year of life among rural infants, contrasting with a 3% infection rate in children under 1 year of age in the metropolitan area. This could be attributed to intense and exclusive breast-feeding for several months in the rural area while in the urban area many infants are not breast-fed at all, or are weaned prematurely. No infection was found in wholly breast-fed infants. Diarrhea associated with Cryptosporidium was watery and without inflammatory cells. Dehydration was common in urban children, but was rapidly corrected by oral rehydration therapy, or by intravenous fluid therapy in some cases. Infections clustered in the warmer, rainy and humid months of the year.

Child, Preschool↗
PubMed1984

[Diarrhea caused by Campylobacter fetus jejuni and other infective agents in children of the rural area of Puriscal, Costa Rica].

Between September 1979 and September 1981 a field study was conducted on the etiology of diarrheal disease in the area of Puriscal, Costa Rica. The presence of enteric pathogens was investigated in the stools of 267 diarrheic children and 190 healthy controls. Both groups belong to yearly cohorts recruited at birth as part of a longitudinal multidisciplinary study of mothers and children. Campylobacter fetus jejuni was identified as the only pathogen in the stools of 24 diarrheic children (9%) and in four healthy controls (2%), a significant difference (p less than 0,05). The clinical features of the episodes were: irritability (77%), blood in stools (35%), anorexia (38,5%), and fever and vomiting (36%). Dehydration was not important among infected children (only one with 5% dehydration). All children received oral salt solutions and only two were treated with antibiotics. Rotaviruses were the main etiologic agents (17%) and Campylobacter ranked second (10,5%). The frequency of enterotoxigenic Enterobacteriaceae was similar in sick children and in controls (10% and 12% respectively).

Anti-Bacterial Agents↗
PubMed1984

[Cryptosporidiosis in children of Costa Rica: a cross section and longitudinal study].

The present report is a systematic study of children, with and without diarrhea from Costa Rican metropolitan areas and southern rural higlands. Children were observed, respectively, at emergencies, Hospital Nacional de Niños, and in a field station in Puriscal; urban children were studied vertically, rural children were observed prospectively (cohort study). Cryptosporidium sp. was found in 4.3% of the cases of diarrhea; diarrhea was generally severe in urban children, but mild in the rural. Infection was detected in urban children less than one year of age: contrasting, no rural infants were found infected, which might be related to breast-feeding, since Puriscal infants were intensively breast-fed for several months, while many urban infants were not breast-fed or were weaned earlier. Cryptosporidium sp. appeared during the warm, rainy and humid months of May through August, when the coccidium was associated with 14.8% of the urban and 15.4% of the rural diarrheas. All urban cases presented dehydration which was corrected with oral rehydration salt therapy, and occasionally with intravenous fluids; dehydration was not common in the rural cases.

Animals↗
PubMed1984

[Rotavirus and Campylobacter fetus jejuni associated with an outbreak of diarrhea in calves].

Rotaviruses and Campylobacter fetus jejuni are ubiquitous agents of diarrheal disease in animals and humans. Under natural conditions they do not seem to cross inter-species barriers; a zoonosis has not been documented for man. However, animal rotaviruses might contribute to the emergence of new reassortment strains in view of their segmented genome, and thus, produce new antigenic variants. On the contrary, Campylobacter fetus jejuni produces a true zoonosis. Man acquires bacilli by ingesting water and foodstuffs contaminated with feces from infected animals. In an outbreak of diarrhea in 22 calves, rotavirus was detected in 8 (36%) and Campylobacter in 6 (27%). Three (14%) calves experienced double infection. There were no human cases involved in this outbreak.

Animals↗
PubMed1983

Treatment of 242 neonates with dehydrating diarrhea with an oral glucose-electrolyte solution.

Two hundred thirty-four of 242 neonates (96.7%) with a mean dehydration of 5.1% body weight were rehydrated with a glucose-electrolyte solution given orally in an average time of 7 44 hours. Eight (3.3%) neonates required intravenous fluid therapy. Emesis was not an obstacle for complete oral rehydration. Hypernatremia, hyponatremia, and acidosis present on admission were corrected within a few hours. Oral rehydration is an entirely satisfactory choice for treatment of uncomplicated dehydration in neonates.

Administration, Oral↗
PubMed1983

Epidemiology of rotaviruses in a cohort of 45 Guatamalan Mayan Indian children observed from birth to the age of three years.

A cohort of 45 children was observed from birth to three years of age in their natural ecosystem to determine patterns of infection, morbidity, and growth. Data from enzyme-linked immunosorbent assay analysis for rotavirus of 5,891 extracts (kept frozen since 1964-1969) of weekly fecal specimens were compared against growth, morbidity, and specimen data files, permitting a retrospective description of the epidemiology of rotavirus infection in the cohort. Rotavirus infections were uncommon in the first months of life in intensively breast-fed infants. Infection increased with age to reach a maximal rate in the six- to 18-month age period. While there was a high incidence of diarrhea in the cohort, rotavirus was associated with only 10% of such episodes. The incidence of rotavirus infection was 1.2 episodes per child-year, and the incidence of rotavirus-associated diarrhea was 0.8 episodes per child-year. Serious outbreaks of rotavirus generally occurred from September through December, with as many as one-half of the children becoming infected. Repeated rotavirus infection was a common phenomenon.

Aging↗
PubMed1983

Diarrhea associated with rotaviruses, enterotoxigenic Escherichia coli, Campylobacter, and other agents in Costa Rican children, 1976-1981.

Rotaviruses, enterotoxigenic Escherichia coli, Salmonella, Shigella, and parasites were investigated in outpatient diarrheic children, and in hospitalized diarrheic and non-diarrheic children, between January 1976 and June 1979. In outpatient cases studied within 4 days of onset of symptoms, rotaviruses were the most common agents (45.3%); E. coli heat-stable enterotoxin ranked second (13.4%); Shigella was third (8.1%); Salmonella was fourth (7.3%). In 63.2%, one or more enteric agents were detected. In hospitalized non-diarrheic children, asymptomatic shedding of pathogens was rarely observed. A later survey of outpatient diarrheic children revealed Campylobacter fetus jejuni in 8%. In 5.5 years of observation rotaviruses were endemic with excess frequency in the dry and cooler months of December and January. The excess occurrence of bacterial pathogens did not coincide with that of rotaviruses.

Campylobacter Infections↗
PubMed1983

Natural history of rotavirus infection in the children of Santa María Cauqué.

A prospective observation of 45 cohort children from birth to three years of age permitted the collection of 5689 weekly stool specimens, along with frequent morbidity, dietary and growth data. Specimens tested by the ELISA showed that all children became infected with rotaviruses during the first three years of life, many repeatedly. The overall rotavirus incidence was 10.6 per 100 child-months (or 1.3 infections per child per year). Rotaviruses exhibited a high pathogenic potential estimated in 65%, but only about 10% of all diarrheas appeared associated with them. Rotaviruses occurred throughout the year but clustering was evident in August through December, with epidemics of greater severity in particular months of certain years. During outbreaks, from a third to one half of all children became infected with rotaviruses in a given month. This and the frequent association of rotaviruses with other enteric agents (34%) suggest that fecal-oral transmission is the main source of infection, a net result of the prevailing low socioeconomic level in the village setting.

Age Factors↗
PubMed1983

Nutritional status of the elderly in Palmares, Costa Rica.

The nutritional status of aged persons living in a small Costa Rican community was evaluated using anthropometric measurements, clinical findings and dietary surveys. Eighteen per cent of the aged were overweight, a condition that occurred more frequently in women than in men. In a random sample of subjects, serum albumin values were low in 45%, serum cholesterol values high in 39%, and hemoglobin values low in 3%. The subjects consumed a simple, repetitive diet with few processed foods which met 80% of requirements for protein, calcium, and iron, although calorie and vitamin A values appeared low. The lack of severe nutritional problems of the elderly was attributed to the family structure, good hygiene and protection from debilitating infectious disease, good community health services, and simple balanced diets.

Aged↗
PubMed1979

Oral rehydration of neonates with dehydrating diarrhoeas.

Thirty-nine of forty neonates with mean dehydration equivalent to 6.7% of body-weight were orally rehydrated with a glucose/electrolyte solution. Only one patient required any intravenous fluids for rehydration. Hypernatraemia and acidosis present at admission were corrected within a few hours without complications. It seems that oral rehydration, is suitable for neonates as well as for children and adults.

Administration, Oral↗