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Biomedical subjects

J R Cruz

Publications and source records attributed to J R Cruz.

At least 19 recordsLinked to original sources
PubMed1995

Fecal excretion of leukotriene C4 during human disease due to Shigella dysenteriae.

Fecal excretion of leukotriene C4 was determined in 26 individuals with dysentery and in 19 healthy controls. Of the patients, five were infected with Shigella dysenteriae type 1, 15 were infected with Shigella flexneri, two were infected with Shigella boydii, and four were infected with Shigella sonnei. Three of the healthy controls were infected with non-dysenteriae Shigellae. All isolates of Shigella dysenteriae type 1 produced Shiga toxin; the other strains were not toxigenic. Patients with dysentery due to Shigella dysenteriae type 1 excreted higher concentrations of leukotriene C4 (median, 3,234 pg/0.05 g of feces) than either ill individuals infected with non-dysenteriae Shigellae (median, 202 pg/0.05 g) or healthy carriers (median, 145 pg/0.05 g) and uninfected controls (median, 129 pg/0.05 g). We propose that Shiga toxin stimulates intestinal mast cells, which release leukotriene C4, contributing to the inflammatory response in Shigella dysenteriae type 1-associated dysentery.

Adult↗
PubMed1994

Tuberculosis case-finding in Nicaragua: evaluation of routine activities in the control programme.

SETTING: The new International Union against Tuberculosis and Lung Disease (IUATLD) tuberculosis strategy developed in the 1980s in Tanzania, Malawi and Mozambique, was simultaneously implemented in Nicaragua. OBJECTIVE: Present results of case-finding, identify trends in incidence and limitations in case-finding and reporting. DESIGN: Data are based upon the traditional reporting system until 1987, replaced as the programme was reorganized. Data were also collected directly from the Central Laboratory, Programme and Laboratory registers during supervision of health centres. RESULTS: Quality control of sputum smears shows 1.8% discordance between peripheral and central laboratories. Notification rate of smear-positive tuberculosis declined 1.7% yearly 1983-1991 and 2.6% for all cases. Half of the patients are new smear-positive pulmonary cases, 40% smear-negative pulmonary cases. Relapses represent 11-13% of all smear-positive patients, children 7-30% of all cases. One-third of extrapulmonary tuberculosis cases are pleural effusions, another third lymphadenitis. 41% of adult patients entered as smear-negative in the programme had no smear reported in the laboratory. CONCLUSIONS: Quality control of sputum smears was established and the reporting system improved in spite of adverse conditions. Notification rate declined gradually. Smears should be done in all patients classified as smear-negative pulmonary tuberculosis.

Adolescent↗
PubMed1992

Genotype-specific in vitro amplification of sequences of the wild type 3 polioviruses from Mexico and Guatemala.

The extensive nucleotide sequence heterogeneity among independent genotypes of wild polioviruses permits the systematic design of genotype-specific molecular reagents. We have prepared two sets of polymerase chain reaction (PCR) primer pairs specific for the genotype of wild poliovirus type 3 recently endemic to Mexico and Guatemala. Nucleotide sequences of a representative wild type 3 virus isolated in Mexico in 1989 differed from the corresponding Sabin 3 (Leon 12 a1b) sequences at 167 of 900 positions within the VP1 region. From the sequence data, wild virus-specific primer pairs were designed to complement regions of high mismatch (greater than 33%) with Sabin 3 templates. Primer binding sites were spaced along the genome so that the predicted amplification products (142 bp and 163 bp) could be easily resolved electrophoretically from the products generated with our Sabin strain-specific primers (Sabin 1: 97 bp; Sabin 2: 71 bp; Sabin 3: 53 bp). RNAs of all wild type 3 poliovirus isolates from Mexico and Guatemala obtained over a 13-year period (1977-1990) served as efficient templates for amplification of the 142-bp and 163-bp products. Genomic templates derived from vaccine-related polioviruses and most heterologous wild polioviruses were inactive under equivalent reaction conditions. Amplifications generating a 114-bp product with a broadly reacting primer pair, matching highly conserved sequences in the 5'-noncoding region, provided a positive control for the presence in samples of poliovirus (or enterovirus) RNAs. Selective amplification of wild Mexico-Guatemala type 3 poliovirus sequences was obtained with either primer set in reactions containing large stoichiometric excesses (up to 10(6)-fold) of vaccine-related RNAs. We have used wild genotype-specific PCR primer sets to facilitate identification of wild polioviruses present in both clinical and environmental samples.

Amino Acid Sequence↗
PubMed1992

Epidemiology of persistent diarrhea among Guatemalan rural children.

A prospective, longitudinal two-year study to determine the epidemiology of persistent (> or = 14 days' duration) diarrhea in rural children of Guatemala was undertaken. Three-hundred and twenty-one children aged 0-35 months were kept under surveillance by twice-a-week home visits. The overall incidence of diarrhea was 0.147 per child-week; the incidence of persistent diarrhea was 0.014 per child-week. The peak of persistent diarrhea was observed in infants below six months of age, with a continuous decline thereafter. This trend in incidence of persistent diarrhea was associated with a higher proportion (16%) of illnesses persisting for more than 13 days in children younger than six months of age as compared to children 30-35 months old (4%). Males had more diarrhea (0.156 per child-week) than females (0.139 per child week). Among children above 18 months of age, the proportion of episodes that lasted for more than 13 days was lower in females than in males.

Acute Disease↗
PubMed1992

Oral gentamicin is not effective treatment for persistent diarrhea.

We conducted a randomized, double-blind, placebo controlled clinical trial of oral gentamicin (10 milligrams/kilogram body weight/day for five days) in treatment of unselected cases of persistent diarrhea (duration 14-18 days at initiation of treatment) among 3-36-month-old children in a rural Guatemalan community. Following random assignment of each child to a treatment group, the appropriate dose of gentamicin or placebo was administered to the child three times daily by a study nurse; this nurse also identified the presence or absence of diarrhea on each day of treatment and for the next two days. Cure was defined as cessation of diarrhea during the five-day treatment period, sustained through at least the two days after completion of treatment. Among 92 evaluable cases who entered the clinical trial, there was essentially no difference in cure rate between gentamicin and placebo treatment groups (42% versus 43%). Enteroadherent strains of Escherichia coli were identified in 46% of children tested in this trial; no significant difference existed between treatment groups in frequency of isolation of this or any other enteropathogen. Among 40 children having successful duodenal cultures immediately prior to beginning treatment, > or = 10(4) aerobic organisms per milliliter of fluid were identified in 12 (30%); treatment groups did not differ substantially with respect to proportion of children identified with this level of duodenal microbial colonization. Failure of gentamicin treatment did not appear to be explained by emergence of resistance, although a small number of resistant enteropathogens were identified near the end of the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1992

Astrovirus-associated diarrhea among Guatemalan ambulatory rural children.

Fecal excretion of astroviruses was monitored in 321 children, 0 to 3 years old, living in the rural highlands of Guatemala. During the longitudinal study, from February 1987 to February 1989, we examined 5,000 stool specimens, including 1,805 collected during 1,369 episodes of diarrhea, 830 collected during the convalescent week, and 216 and 244 collected 2 weeks and 1 week, respectively, before the onset of diarrhea. Routine specimens were taken once a month from every child who had been free from diarrhea for at least three consecutive weeks. Of the children, 124 (38.6%) excreted astroviruses during the study. In total, we identified 184 infections by astroviruses. Of the samples collected 2 weeks and 1 week before the initiation of symptoms, 0.9 and 4.9%, respectively, were positive, while 7.3% of the diarrhea episodes were associated with astroviruses. Of the convalescent specimens, 3.4% were shown to be positive; 2.4% of the 1,905 specimens taken in diarrhea-free periods contained astroviruses. Infections by other potential enteropathogens were documented in 54 and 65% of the asymptomatic and symptomatic astrovirus infections, respectively. Diarrhea associated with astroviruses alone had a median duration of 5 days and was associated with vomiting in 8.6%, with fever in 17.1%, with dehydration in 5.7%, and with loss of appetite in 34.3% of the episodes. Diarrhea due to astroviruses was accompanied by negative changes in weight gain. Astrovirus diarrhea contributes to the high morbidity observed in young children living under poor conditions and has a deleterious effect on their nutritional status.

Body Weight↗
PubMed1990

Colors, humors and evil eye: indigenous classification and treatment of childhood diarrhea in highland Guatemala.

Focal group interviews on indigenous perceptions and reported management of childhood diarrhea were conducted in 1987-88 in Guatemala as a part of a prospective epidemiological field study of chronic diarrhea. Six cognitive schemata were identified, each with specific causes, a linked progression of concepts, symptoms, signs, and diagnostic characteristics. Nearly all were related to the humoral theory of disease, including the concept of evil eye. Diarrheal disease was conceptualized in the village as a set of processes which could be either "hot" or "cold" rather than as an unchanging single-symptom entity occupying only one spot on the humoral continuum. Clarification of the temporal relationship between concepts was found to be essential to the understanding of these indigenously-defined schemata. Stool color reflecting humoral theory was the primary concept used in household-level diagnosis. Reported behavior associated with these cognitive schemata (traditional treatments, pharmaceutical and dietary management) showed remarkable constancy, and adhered for the most part to the humoral concept of equilibrium. These included the use of oral rehydration solutions (ORS) and liquids. The applied importance of humoral theory to home-based use of ORS is discussed briefly as is the indigenous definition of dehydration.

Child, Preschool↗
PubMed1990

Adenovirus types 40 and 41 and rotaviruses associated with diarrhea in children from Guatemala.

From March 1987 to February 1988, fecal excretion of adenovirus types 40 and 41 and rotavirus serotypes in 194 children (age, 0 to 3 years) from a rural community of Guatemala was monitored. In total, 458 samples taken during 385 episodes of diarrhea and 191 specimens obtained during symptom-free periods were examined by enzyme-linked immunosorbent assay. Fifty-seven children hospitalized because of diarrhea were also studied. Among the rural children, 43 (22.2%) excreted adenovirus types 40 and 41 and 20 (10.3%) shed rotaviruses. Adenovirus types 40 and 41 were associated with 54 (14.0%) illnesses, and rotaviruses were associated with 18 (4.7%) illnesses. Asymptomatic infections with adenovirus types 40 and 41 were documented in nine children and with rotaviruses in two children. Fifteen typeable rotaviruses were identified as serotype 2. In the hospital population, 36 (63.2%) children had viral infections. Rotaviruses were identified in 29 (50.9%) and adenovirus types 40 and 41 were identified in 15 (31.2%) of 48 subjects tested. Dual infections by these viruses were found in eight children. Of 22 typeable strains of rotaviruses, 9 (34.6%) were serotype 1, 12 (46.1%) were serotype 2, and 1 (3.8%) was serotype 3. All the children infected with serotype 2 rotavirus were coinfected with other enteric pathogens, while only three (37.5%) of those infected with rotavirus serotype 1 excreted another pathogen. Adenovirus types 40 and 41 are an important cause of gastroenteritis in both ambulatory and hospitalized Guatemalan children. There seems to be a difference in the pathogenicity among rotavirus serotypes.

Adenoviridae Infections↗
PubMed1989

Thymosin alpha 1 in milk specimens from Guatemalan women.

Thymosin alpha 1 was determined in milk samples obtained from 67 Guatemalan women 5 days, and 1-3 and 6-18 months postpartum. All the specimens collected 5 days after delivery contained measurable levels (583 +/- 304 pg/ml) of thymosin alpha 1 but only 33% of those obtained 1-3 months postpartum and none collected thereafter did. Since thymosin alpha 1 has been shown to increase T-cell mediated immunity, and to enhance host resistance to infection, it may play an important role in the maturation of mucosal immunity and host resistance in general in the neonate. This study is the first to document the presence of a thymic hormone in early postpartum milk.

Female↗
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↗
PubMed1989

[Nutritional status of Guatemalan preschool children hospitalized for acute respiratory infections].

Nutritional status (weight-for-age, length-for-age, and weight-for-length) was determined in 678 children aged 0-59 months, admitted to the San Juan de Dios General Hospital in Guatemala City with signs and symptoms of acute respiratory infections. Five hundred and fifty seven (82.2%) cases were bronchopneumoniae; 62 (9.1%) were pneumoniae, and 43 (6.3%) were bronchiolitis. Five hundred and seventy (82.6%) children lived in the urban zones of the capital city and 118 (17.4%) in the municipalities of the Department of Guatemala. Deficit in weight-for-age was found in 188 (27.8%) cases, while 176 (25.9%) showed a deficiency in length-for-age. In terms of weight-for-length, 84 (12.4%) were below -2.00 standard deviations of the reference curve. The children from out of the city showed the highest proportions of malnutrition. Monitoring of nutritional status of hospitalized children with infectious diseases can provide valuable information, not only for their management, but also for parental health education.

Acute Disease↗
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↗