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Biomedical subjects

G Figueroa

Publications and source records attributed to G Figueroa.

At least 37 records · Page 2Linked to original sources
PubMed1993

[Plasma estradiol levels and duration of lactation amenorrhea].

In Temuco, Chile, 114 women in fully nursing, were studied, according to their length of lactational amenorrhea and their relation with estradiol levels at 3th postpartum month. Sixty six (58%) recovery their menses before the 6th postpartum month. The length of lactational amenorrhea was 100.7-5.2 and 277 +/- 10.6 days, for those mothers who were with menses and amenorrhea, respectively. The estradiol levels were 88 pmol/l higher in the woman with short length of lactational amenorrhea. This study corroborate, that short length of lactational amenorrhea is a condition highly frequent in Chilean population. The difference in the estradiol levels may be a indicators of the early recovery of the postpartum fertility.

Adolescent↗
PubMed1992

Adherence of Helicobacter pylori to HEp-2 cells.

The adherence of 25 strains of Helicobacter pylori was evaluated in HEp-2 cells. These bacterial isolates, obtained from Chilean patients with gastric disorders, were also tested for haemagglutination of human red blood cells. Adherence of HEp-2 cells was expressed as a common property of all strains, irrespective of whether the cultures were grown on semi-solid or in liquid media. Previous reports that haemagglutinating activity was present in cells grown only on semi-solid media were confirmed. Adherence to HEp-2 cells was suppressed when bacterial cells were pretreated with homologous or heterologous whole human serum, containing specific antibodies of H. pylori. Adherence remained unaltered when bacterial cells were similarly treated with normal serum lacking specific antibodies. These observations imply that adhesions are expressed in vivo and suggest that an adherence mechanism, not depending on the expression of specific haemagglutinin antigen, operates for H. pylori.

Bacterial Adhesion↗
PubMed1992

Field trial of an infant formula containing anti-rotavirus and anti-Escherichia coli milk antibodies from hyperimmunized cows.

Two groups of 124 and 108 children, respectively, living in urban Santiago, Chile in low socioeconomic conditions were prospectively followed for 6 months for their incidence of diarrhea. Each cohort was divided into two subgroups receiving either a commercial milk formula or the same formula containing 1% (wt/wt) bovine milk immunoglobulin concentrate from cows hyperimmunized with human rotaviruses and the major enteropathogenic Escherichia coli (EPEC) serogroups. Neither group differed with respect to incidence of diarrhea (98 episodes in 117 treated children versus 95 episodes in 115 control children), duration and clinical symptoms of diarrhea, and weight gain. Furthermore, neither group differed with respect to isolation of rotavirus (14 and 13 isolates in treatment and control groups, respectively) and isolation of enteropathogenic E. coli (14 and 15 isolates in treatment and control groups, respectively). The treatment but not the control formula contained neutralizing antibody against all human rotavirus serotypes. Titers were comparable to human breast milk samples. All isolated EPEC serogroups were included in the vaccine used for the immunization of the cows. The treatment, but not the control formula, protected mice against a lethal challenge with an EPEC strain. In conclusion, feeding an antibody-supplemented formula had no positive effect on diarrheal diseases under the conditions of a fairly well-controlled small-scale field trial.

Animals↗
PubMed1992

Hygiene habits and carriers in families with a child who has had typhoid fever.

The relationship between asymptomatic shedding of bacterial enteropathogens and the hygiene habits of families who have had a child with typhoid fever (TF) are investigated. The sample was made up of 80 families: 40 families in which one child had had TF (Group A) and 40 in which no children or either of the parents had had a history of TF (Group B). In each group 20 families belonged to a low socioeconomic status (SES) and 20 to a high SES. A structured interview was used to evaluate the SES and the hygiene habits of the child; observations were made to measure the hygiene habits of the family (toilet, kitchen and food preparation) and bacteriological studies (fecal samples and hand markers). Results show that carriers were more frequent in Group A than in Group B. The bacterial species found were significantly more numerous in Group A than in Group B (fecal samples: E. coli, the classic serotypes, Shigella ssp, and hand markers: E. coli). Families of Group A had higher carriage rates than those of Group B. Finally there exists a significantly higher association between inadequate hygiene habits and carrier families. These results show the need to teach specific habits of proper hygiene to the entire population, because the fact of belonging to the high SES does not in itself preclude inadequate hygiene habits.

Adolescent↗
PubMed1992

[General and ethnic factors associated with the duration of lactation amenorrhea].

114 women in fully nursing, were studied, according to the length of lactational amenorrhea and their relation with general characteristics and ethnic group. Of the 114 mothers, 66 (58%) recovery their menses before the 6th postpartum month. The length of lactation was 100.7 +/- 5.2 and 277.9 +/- 10.5 days, for those mothers who were with menses and amenorrhea until the 6th postpartum month, respectively. A group of Mapuche women had a higher length of lactational amenorrhea and we found differences in the frequency of suckling episodes at night. This study corroborate, that short length of lactational amenorrhea is a condition highly frequent in Chilean population and it does not have a relation the nursing pattern in general population. However, the difference in the length of lactational amenorrhea in specific ethnic group, can include some general or behavioral factors of breast-feeding.

Adolescent↗
PubMed1991

[Hygiene habits at the family level and typhoid].

We studied the relation of habits related to the fecal-oral cycle and incidence of typhoid fever in children attending the school system for 1 to 2 years and in their families. The goal was to identify a predictor to detect families at risk for typhoid fever. A sample of 80 school-mother dyads, 40 of high and 40 of low socio-economic status was studied. 20 children in each group had had typhoid fever. Logistic regression analysis allowed to identify dirty edges of the toilet bowl and nail eating habits as highly specific (97%) and sensitive (82%) index of risk. The predictor held both in high and low socio-economic groups and could be used to identify families at risk of developing typhoid fever.

Adult↗
PubMed1991

[Evaluation of an immunoenzyme technique (ELISA) to diagnose typhoid fever].

The efficiency of an ELISA method, designed to detect polyvalent IgG and IgM antibodies to Salmonella typhi polysaccharide was evaluated in patients admitted or convalescing from typhoid fever and in control subjects. Polyvalent antibodies to S typhi were demonstrated in 28/30 (93%) typhoid patients, 0/11 bacteremic patients (E coli or S paratyphi A) and 0/15 asymptomatic individuals. Widal test showed significant anti-0 agglutinin values (> = 1: 160) in only 12/30 (40%), 1/11 (9%) and 0/15 subjects from each group respectively. Typhoid patients tested on admission or at discharge showed similar high reactivity rates to ELISA. On the contrary, the Widal test detected only 2/15 (13%) patients on admission (p < 0.02) and 10/15 (67%) at discharge. These results and additional immunoblotting tests suggest that ELISA developed to detect polyvalent anti-LPS antibodies could represent a highly specific diagnostic tool to confirm typhoid fever in endemic areas.

Adult↗
PubMed1991

[Influence of basal and post-feeding prolactin levels on amenorrhea during breast feeding].

Forty five women, with exclusive breastfeeding were studied, (the objective was) to explore the relationship between: basal plasma prolactin (PRL) levels and post-suckling with the duration of postpartum amenorrhea. Blood samples for measurements of PRL were taken at the third month postpartum, before an episode of suckling and 30 minutes after the suckling was initiated. The average level of basal PRL was 1,033 +/- 113 mIU/L (mean +/- SE). Women who presented long periods of amenorrhea, had an increase of the basal PRL in 632 mIU/L (X), compare to those women who had their menses before 180 days postpartum (p = 0.036) women with longer amenorrhea (p = 0.06). However there were no relationship between the menses at the sixth month postpartum and the increase of post-suckling PRL (delta PRL). In this study it was found that the levels of basal PRL had correlation with the duration of the amenorrhea, in women with exclusive breastfeeding.

Adult↗
PubMed1990

Biotypes, serogroups and antibiotic susceptibility of Campylobacter jejuni and Campylobacter coli in Chile.

Phenotypic markers were studied in 105 strains of thermophilic campylobacters isolated from human beings, animals and drinking water in Santiago, Chile. The strains were identified as Campylobacter jejuni (n = 49) and Campylobacter coli (n = 56). Biotypes I and II (Lior schema) accounted for 96% C. jejuni isolates, the other 4% being biotype IV but the two biotypes of C. coli were about equally represented. A total of 28 serogroups (Lior's heat-labile antigens) were identified. Lior 13, 9, 79, 2 and 4 were prevalent among the C. jejuni, while Lior 8, 21 and 29/75 were prevalent among the C. coli isolates. These serogroups accounted for 73% all isolates. The distribution of biotypes and serogroups in patients and asymptomatic persons were similar. Human campylobacters were often resistant to ampicillin (31%) but sensitive to erythromycin and furazolidone. Swine C. coli isolates proved resistant to streptomycin (46%), tetracycline (38%) and erythromycin (15%). Determination of phenotypic and serological characters provides valuable epidemiological markers in the study of campylobacter infections.

Animals↗
PubMed1990

[The IgG antibody response in patients colonized by Helicobacter pylori].

The IgG antibody response specific to Helicobacter pylori was evaluated through ELISA in a group of 92 gastric patients colonized by this bacteria. 74 had gastritis and 19 gastroduodenal ulcer. Three control groups were studied in a similar way: normal adult volunteers (n = 17), adults with E coli or S typhi bacteremia (n = 30) and normal infants (n = 30). IgG antibody response to H pylori was demonstrated in 98% of colonized patients and 0% of infants. Asymptomatic individuals and those with bacteremia had high rates of antibody response (76 and 90% respectively), although this rate and also the titers of antibody response were significantly lower than that of colonized patients (p < 0.05). ELISA reactive sera from colonized patients and asymptomatic individuals evidenced a similar antibody pattern when tested by blotting. This profile was absent in non reactive sera, including those with high antibody titers to C jejuni. The presence of specific IgG antibodies to H pylori in the majority of colonized gastric patients and asymptomatic adults suggests that this infection is very common in our population.

Adolescent↗
PubMed1989

Prospective study of Campylobacter jejuni infection in Chilean infants evaluated by culture and serology.

A prospective study of Campylobacter jejuni infection was performed during a 6-month period in a cohort of 198 Chilean infants. Surveillance was based on biweekly home visits by a team of trained nurses. C. jejuni colonization was studied by culturing stool samples from diarrheal episodes and paired asymptomatic controls and by performing an enzyme-linked immunosorbent assay developed to measure C. jejuni outer membrane protein polyvalent antibodies in a representative group of infants. C. jejuni was isolated from 30 of 299 diarrheal episodes (10%) and from 17 of 304 samples from asymptomatic infants (6%). Significantly higher (P less than 0.05) C. jejuni illness/infection ratios were found in infants less than 9 months old. Polyvalent antibodies to C. jejuni were found in 27 of 89 serum samples (30%). The lowest prevalence (4%) was observed among infants less than 9 months old, and the highest was found in patients older than 15 months (63%; P less than 0.01). Data obtained by analysis of paired serum samples revealed a significant increase in the number of seropositive individuals, from 8% on admission to 50% at the end of the protocol (P less than 0.001). The change in the immune status of these infants was associated with symptomatic infection in 9 of 18 cases. The antibody rise found in the remaining nine infants suggested the presence of asymptomatic C. jejuni infections. This inference was documented by the isolation of C. jejuni from stools of two of these infants when the infants were randomly studied while asymptomatic. This study points out the impact of C. jejuni-associated diarrheal episodes and the high frequency with which asymptomatic infections elicit specific antibodies in infants living in areas such as Chile.

Age Factors↗
PubMed1988

Enteropathogenicity of Aeromonas species isolated from infants: a cohort study.

The significance of Aeromonas spp. as potential enteric pathogens was evaluated in a cohort of 187 infants aged 3-18 months during a 16-week summer period. Aeromonas spp. were isolated from 14 of the 196 (7.1%) diarrhoeal episodes detected and from eight (5.2%) of 153 samples from paired asymptomatic infants. Carriage of bacterial enteropathogens excluding Aeromonas spp. was detected in a high proportion (23%) of the asymptomatic children. Almost all of the seven isolates of Aeromonas sobria were enterotoxigenic, invasive and beta-haemolytic. In contrast, none of the seven Aeromonas caviae strains had these virulence-associated characteristics. The only isolate of Aeromonas hydrophila produced cytotoxic enterotoxin and was invasive. Plasmid analysis of selected strains did not correlate with these two properties or with antibiotic resistance. Nevertheless, the latter was found in an important proportion of the isolates. The diarrhoeal episodes, in which Aeromonas spp. were detected, lasted significantly longer, i.e. 17.2 days when the strains were invasive and/or toxigenic as compared with 4.3 days (P less than 0.001) in patients harbouring strains lacking both traits. These results reinforce the need to characterise virulence determinants before assigning any pathogenic role to Aeromonas spp. isolated from faecal specimens. Our findings also suggest the need for adequate antibiotic treatment in patients with confirmed Aeromonas spp. having enterotoxigenic and/or invasive properties.

Aeromonas↗
PubMed1988

Characterization of enteroinvasive Escherichia coli strains isolated from children with diarrhea in Chile.

Analysis of stool samples from 912 cases of diarrhea among Chilean infants and 1,112 controls resulted in the isolation of 17 enteroinvasive Escherichia coli (EIEC) strains from diarrhea cases (1.9%) and 3 EIEC from the asymptomatic controls (0.3%). Biochemical analysis of the 20 isolates showed variability among them. However, the majority were lysine decarboxylase negative and nonmotile and utilized sodium acetate. The strains belonged to the O groups 28ac, 124, 143, or 144 or were untypable with the antisera used. Most of them had conjugative plasmids which mediated multiple antibiotic resistance. There was a strong correlation in this group of strains between a positive Sereny test, the presence of a plasmid of 120 megadaltons, and hybridization with the invasiveness probe, an HindIII fragment derived from the plasmid pPS15A. The isolates had a wide range of plasmid profiles. Bioassays and colony and Southern hybridization tests with iron uptake DNA probes indicated that 80% of the EIEC strains produced aerobactin and expressed its receptor, the genes for which are known to be chromosomally located.

Anti-Bacterial Agents↗
PubMed1988

Further characterization of Escherichia coli O153:H45, an ETEC serotype disseminated in Chile.

The newly described stable enterotoxin producing, enterotoxigenic Escherichia coli, serotype O153:H45, capable of expressing colonizing factor antigen I, is frequently isolated as a cause of diarrhea among Chilean children. Hybridization studies of five new strains confirmed previous results which indicated that the stable enterotoxin genes are contained in nonconjugative plasmids ranging in size from 81 to 87 kilobases. The strains expressed similar antibiotic resistance and metabolic properties but differed in their plasmid content.

Antigens, Bacterial↗
PubMed1987

Depressive symptomatology in northern Mexico adults.

A cross-sectional field survey of 991 people in Tijuana, Mexico, a border city experiencing unbridled population growth, was designed to measure levels of depressive symptoms and identify correlates using the Center for Epidemiological Studies Depression measure (CES-D). Bivariate and multivariate analyses of the data indicate that similar variables are highly associated with depressive symptoms in the US and Mexico: low socioeconomic status, female gender, disrupted marital status, unemployment, and poor health. Risk-for-caseness is 19.1 per cent for males and 33.0 per cent for females.

Adolescent↗
PubMed1987

Chronic environmental enteropathy in a temperate climate.

Forty-three apparently healthy young adult male volunteers underwent an evaluation of their nutritional status, blood chemistry and faecal excretion of enteropathogens, which did not reveal current malnutrition or illnesses. Ten of them were further studied for small intestinal histology, culture of aerobic and anaerobic bacteria in the duodenal juice, disaccharidase activities, glucose absorption and faecal excretion of fat and nitrogen. The study revealed mild morphological changes associated with the appearance of anaerobic bacteria in the upper intestine, decreased glucose transport and increased faecal losses of nitrogen. Although all these changes were rather mild, they may be significant for people whose diet is of borderline nutritional quality.

Adult↗
PubMed1986

Acute diarrhoea and asymptomatic infection in Chilean preschoolers of low and high socio-economic strata.

Preschoolers who belonged to the high (Group I, n = 112) or the low (Group II, n = 90) socio-economic stratum were followed prospectively for six months. Mean monthly incidence of diarrhoea was 3 and 7 episodes per 100 children for Group I and Group II respectively (p less than 0.001). Episodes were shorter and affected a smaller proportion of children in Group I (p less than 0.002 and p less than 0.05), respectively). Bacterial enteropathogens were recovered in 12.6% and 13.5% of the episodes in Group I and Group II and parasites in 15.4% and 62.8%, respectively. Rotavirus was detected once in each group. Asymptomatic carrier rates for enteropathogenic bacteria were 12.0% in Group I and 7.2% in Group II. The corresponding figures for parasites were 28.2% and 62.8% (p less than 0.001). Nutritional status was normal in all children. These results suggest that socio-economic stratum plays an important role in the characteristics of diarrhoeal illness in the groups which conform the population of the less developed countries. Acute diarrhoea is less frequent in preschoolers living in Santiago than in other developing areas. Rates of asymptomatic infection are high.

Acute Disease↗