"Safe Foods" or "Fear Foods": the implications of food avoidance in college students from low- and middle-income countries.

PURPOSE: The primary objective of this study was to explore if self-reported food avoidance (fats, carbohydrates and protein) exists among college students in low- and middle-income countries (LMICs) and its relationship with body mass index (BMI), dieting, mood/anxiety symptoms, physical activities and general health knowledge. METHODS: This study is a subset (N = 6096) of a larger 26 LMICs cross-sectional survey, which consisted of 21,007 college students. We ascertained socio-demographic information, food avoidance, physical activities, dieting behaviours, depressive and PTSD symptoms, and recorded anthropometric measurements. Chi-square analyses assessed the relationship between predictor variables and food categories eliminated from participants' diet. Multiple logistic regression assessed if food avoidance predicts outcome variables such as binge drinking, high physical activity, being underweight, exhibiting significant depressive and PTSD symptoms. RESULTS: Food avoidance exists in as many as one-third of college students in low- and middle-income countries, with this being more likely in persons who are trying to lose weight whether by dieting or otherwise. Food avoidance was associated with higher BMI, depressive symptoms, and high intensity exercises, as well as the level of health knowledge influencing the types of food avoided. A significant difference was noted between lower middle-income and upper middle-income countries with respect to the foods they avoided. CONCLUSION: Despite being knowledgeable about health-related behaviours, we found that college students in our sample were not that different from those in developed countries and may be influenced by a similar advice given by non-experts about macronutrients. These results hold implications for intervention programmes and policy makers. LEVEL OF EVIDENCE: Level V, descriptive cross-sectional survey.

Seroprevalence of Trypanosoma cruzi infection in three rural communities in Guatemala.

A systematic, house-based serological survey for Trypanosoma cruzi seroreactivity was conducted in three contiguous communities in Olopa municipality, Chiquimula Department, Guatemala. Blood samples from a total of 292 individuals in 63 households were examined by enzyme-linked immunosorbent assay. The seropositive rate ranged from 0% to 20.8% for the three communities, with a mean of 15.1%. Log-linear models showed that seroprevalence was significantly related to age (P < 0.005) but not to sex. However, when the age group with the lowest prevalence (1-9 years) was excluded from the analysis, age was not a significant factor (P = 0.55). Data from a stratified sample collected at the same time were combined with those of the systematic sample to analyze the relationship between seropositivity and possible explanatory variables. Log-linear models, based on 586 individuals in 129 households from the two surveys, revealed a significant positive association between seropositivity and thatched roofs (P = 0.01).

Cytokine profiles during experimental Chagas' disease.

People infected with Trypanosoma cruzi remain so for life, yet only 30-40% of these individuals develop characteristic chagasic cardiomyopathies. Similarly, when infected with the Brazilian strain of T. cruzi, DBA/2 mice develop severe cardiac damage while B10.D2 mice do not. To better understand the immunological parameters that may be involved in the disease process, we have used this murine model (DBA/2 vs B10.D2) and compared the changes in cytokine production during the course of infection with T cruzi. Concanavalin A (Con A) stimulation of spleen cells harvested during the acute phase (day 30) resulted in similarly high levels of IFN-gamma in both mouse strains. However, the amount of IFN-gamma in supernatants from cultures of B10.D2 spleen cells initiated during the chronic phase (day 72) was at subacute levels, whereas secretion by chronic DBA/2 spleen cells remained high. In addition, Con A-stimulated spleen cells from acute DBA/2 mice produced approximately twice as much IL-10 and significantly more IL-4 than cells from B10.D2 mice. IL-4 secretion remained low by cells from chronic B10.D2 mice, but when using cells from chronic DBA/2 mice, levels continued to increase beyond the already high levels secreted by cells harvested during the acute phase. Proliferative responses to Con A stimulation by spleen cells from DBA/2 mice were significantly higher than those from B10.D2 mice in both the acute and chronic phases. These data suggest that enhanced responses in DBA/2 mice, which may be related to a higher parasite burden, a lack of down-regulation, and/or the onset of autoimmune phenomena, correlate with the more severe cardiomyopathy seen in pathopermissive mice.

Cytokine profiles during experimental Chagas' disease

People infected with Trypanosoma cruzi remain so for life, yet only 30-40 percent of these individuals develop characteristic chagasic cardiomyopathies. Similarly, when infected with the Brazilian strain of T. cruzi, DBA/2 mice develop severe cardiac damage while B10.D2 mice do not. To better understand the immunological parameters that may be involved in the disease process, we have used this murine model (DBA/2 vs B10.D2) and compared to changes in cytokine production during the course of infection with T. cruzi. Concanavalin A (Con A) stimulation of spleen cells harvested during the acute phase (day 30) resulted in similarly high levels of IFN-gamma in both mouse strains. However, the amount of IFN-gamma in supernatants from cultures of B10.D2 spleen cells initiated during the chronic phase (day 72) was at subacute levels, whereas secretion by chronic DBA/2 spleen cells remained high. In addition, Con A-stimulated spleen cells from acute DBA/2 mice produced approximately twice as much IL-10 and significantly more IL-4 than cells from B10.D2 mice. IL-4 secretion remained low by cells from chronic B10.D2 mice, but when using cells from chronic DBA/2 mice, levels continued to increase beyond the already high levels secreted by cells harvested during the acute phase. Proliferative responses to Con A stimulation by spleen cells from DBA/2 mice were significantly higher than those from B10.D2 mice in both the acute and chronic phases. These data suggest that enhanced responses in DBA/2 mice, which may be related to a higher parasite burden, a lack of down-regulation, and/or the onset of autoimmune phenomena, correlate with the more severe cardiomyopathy seen in pathopermissive mice.

Prevalence of anti-Taenia solium antibodies in sera from outpatients in an Andean region of Ecuador.

Sera from 9,254 individuals that presented at one of three outpatient clinics in Quito, Ecuador were assayed by indirect hemagglutination for the presence of antibodies reactive with antigens from Taenia solium cysts. Immunoblot analysis of 81 selected sera with IHA titers ranging from 0 to 1,028 showed that a titer of > or = 32 was suggestive of exposure to the parasite. Nine percent (9%) of the 9,254 patients had titers of 32 or greater. Of 3,503 sera from one clinic, which included sera from food handlers undergoing yearly physicals, 390 (11%) were positive. In addition, a correlation with age was seen in some, but not all, populations. In situations where age-related effects were noted, the highest incidence was seen in the youngest (0-20 years) and in the oldest (51-60 years) group. Thus, a resurgence of infection after a period of lower prevalence may be developing. Overall, this study shows that cysticercosis is relatively common and potentially a serious health problem in this region.

Blood donors in a vector-free zone of Ecuador potentially infected with Trypanosoma cruzi.

Chagas' disease is a serious health problem for the population of South and Central America. Blood transfusion is the second most common way in which this disease is transmitted. Several studies have reported finding Trypanosoma cruzi-infected blood in blood banks in endemic areas. Serum samples were taken from the Red Cross blood bank in Quito, a nonendemic and vector free zone of Ecuador, in December 1992 and May 1993 and analyzed by enzyme-linked immunosorbent assay using crude epimastigote extract from the Brazil strain of T. cruzi. Of 162 samples examined in December 1992, 12.1%, 13.9%, and 74% were seropositive, indeterminate, and seronegative, respectively. Of 173 samples taken in May 1993, 6.2%, 17.9%, 75.9% were seropositive, indeterminate, and seronegative, respectively. Western blot analysis of these sera using sodium dodecyl sulfate-polyacrylamide gel electrophoresis with 7.5% gels separated T. cruzi epimastigote antigen proteins, and revealed a reaction with a 205-kD doublet antigen with most of the seropositive samples. These results indicate the necessity for long-term screening of blood bank donors to reduce the risk of transfusion transmission of the disease even in areas of endemic countries where the vector is not present.

Reconnaissance study of macrofossils from the upper purus river - Western Amazônia.

Fossils of wood, bone and teeth found along the Upper Purus River f Amazonia. were studied using conventional microscopy and scanning electron microscopy. Mass spectometry was also used to investigate minor and trace element signatures of bone samples.The microsopy studies showed that there was little alteration of original textures. In the fossil wood samples, identified In thin section as tropical hardwood trees, the replacement of the original material with siderite suggests that fossilization occured in shallow sediments in which interstitial waters were saturated with respect to iron carbenate. In samples of both fossilized bone and wood, precipitation of secondary iron phases was commonly observed in cracks and voids. Other secondary phases Included silica, iron oxides, manganese carbonate. The intimate assciation f these secondary phases with the original biological structures could be evidence for a microbiological role in the formation of these phases. The similarity in rare earth element (REE) signatures for 2 fossil bone samples from different modern locations indicates their having shared similar diagenetic histories.The virtually complete preservation of original textures suggests that microscpic studies could be useful in classifying fossil and even in identifying original materials. Rare carth signatures in fossilized bone may reflect ground water compositions at the time of fossilization.

Fósseis de madeira, ossos e dentes achados no Estado do Amazonas, ao longo do rio Purus e do rio Acre, foram estudados, usando-se microscópia convencional e micro-varredura. A espectrometria de massa foi utilizada para investigar os níveis tos menores e traços em algumas amostras de osso fossilizado. Os estudos microscópicos mostram que há pouca alteração das texturas originais. As amostras de madeira fossilizada foram identificadas em lâmina delgada como madeira de lei. Nestas amostras a substituição da matéria original por siderita sugere que a fossilização ocorreu em sedimentos rasos, nos quais as águas intersticiais foram saturadas pelo carbonato de ferro. A precipitação de fases secundarias de ferro foi observada freqüentemente nas rachaduras e vãos, nas amostras tanto de ossos fossilizado como de madeira fossilizada. Outras fases secundárias incluem a sílica, óxidos de ferro e carbonato de manganês. A associação ín tima dessas fases secundárias com as estruturas biológicas originais pode ser evidência para um papel microbiológico na formação dessas fases. Os padrões de concentração semelhante de terras raras em dois ossos em localidades modernas diferentes indicam histórias diagenéticas semelhantes. A preservação virtualmente completa das texturas originais sugere que estudos microscópicos podem ser úteis na classificação dos fósseis e até na identificação de materiais originais. Padrões de concentração de terras raras em ossos fossilizados podem refletir as composições de água subterrânea na época de fossilização.

Reconnaissance study of macrofossils from the upper purus river - Western Amazônia

Fossils of wood, bone and teeth found along the Upper Purus River f Amazonia. were studied using conventional microscopy and scanning electron microscopy. Mass spectometry was also used to investigate minor and trace element signatures of bone samples.The microsopy studies showed that there was little alteration of original textures. In the fossil wood samples, identified In thin section as tropical hardwood trees, the replacement of the original material with siderite suggests that fossilization occured in shallow sediments in which interstitial waters were saturated with respect to iron carbenate. In samples of both fossilized bone and wood, precipitation of secondary iron phases was commonly observed in cracks and voids. Other secondary phases Included silica, iron oxides, manganese carbonate. The intimate assciation f these secondary phases with the original biological structures could be evidence for a microbiological role in the formation of these phases. The similarity in rare earth element (REE) signatures for 2 fossil bone samples from different modern locations indicates their having shared similar diagenetic histories.The virtually complete preservation of original textures suggests that microscpic studies could be useful in classifying fossil and even in identifying original materials. Rare carth signatures in fossilized bone may reflect ground water compositions at the time of fossilization.

Fósseis de madeira, ossos e dentes achados no Estado do Amazonas, ao longo do rio Purus e do rio Acre, foram estudados, usando-se microscópia convencional e micro-varredura. A espectrometria de massa foi utilizada para investigar os níveis tos menores e traços em algumas amostras de osso fossilizado. Os estudos microscópicos mostram que há pouca alteração das texturas originais. As amostras de madeira fossilizada foram identificadas em lâmina delgada como madeira de lei. Nestas amostras a substituição da matéria original por siderita sugere que a fossilização ocorreu em sedimentos rasos, nos quais as águas intersticiais foram saturadas pelo carbonato de ferro. A precipitação de fases secundarias de ferro foi observada freqüentemente nas rachaduras e vãos, nas amostras tanto de ossos fossilizado como de madeira fossilizada. Outras fases secundárias incluem a sílica, óxidos de ferro e carbonato de manganês. A associação ín tima dessas fases secundárias com as estruturas biológicas originais pode ser evidência para um papel microbiológico na formação dessas fases. Os padrões de concentração semelhante de terras raras em dois ossos em localidades modernas diferentes indicam histórias diagenéticas semelhantes. A preservação virtualmente completa das texturas originais sugere que estudos microscópicos podem ser úteis na classificação dos fósseis e até na identificação de materiais originais. Padrões de concentração de terras raras em ossos fossilizados podem refletir as composições de água subterrânea na época de fossilização.