Protein quality evaluation in rats of typical diets for 4- to 6-year-old children from different socioeconomic areas living in Oaxaca, Mexico

Legumes and cereals are principal sources of energy and protein in developing countries. In Oaxaca, Mexico, corn is the primary agricultural crop, therefore corn tortillas and beans are the main energy and protein sources. The objective of this study was to evaluate the protein quality in rats of typical diets for 4- to 6-year-old children from different socioeconomic areas in Oaxaca, Mexico. Composite diets representing the typical diets were formulated and fed to male weanling rats for 10 days. A control diet using casein as the reference diet and one free of nitrogen were included in the study. The apparent protein digestibility was determined in rats using the chromic oxide marker technique and the data was statistically analyzed for differences between control and experimental diets. Rats fed the diet of low income children gained about 2 g/day compared to about 3.8 g/day for the rats fed the control (casein) diet and had the lowest weight gain/g of protein intake. The NPR was 3.52 compared to 4.31 for the control diet. This diet is 67% vegetable protein and 33% animal protein. The diet for the medium income group contained a higher percentage of animal protein, 76% and thus higher digestibility, 78%. The results of this study indicate that the protein quality of children's diets in Oaxaca, Mexico, need to be improved.

Diagnostic utility of a multiplex herpesvirus PCR assay performed with cerebrospinal fluid from human immunodeficiency virus-infected patients with neurological disorders

We used a multiplex nested-PCR assay for the simultaneous detection in cerebrospinal fluid (CSF) of five human herpesviruses (HVs) (cytomegalovirus [CMV], Epstein-Barr virus [EBV], varicella-zoster virus [VZV], herpes simplex virus [HSV], and human herpesvirus 6 [HHV-6]) in a clinical evaluation of human immunodeficiency virus (HIV)-infected patients with neurological disorders. This method, which has the advantages of being rapid and economical, would be of particular interest for the diagnosis of neurological syndromes caused by more than one HV. We studied 251 CSF samples from 219 patients. HV DNA was demonstrated in 93 (37%) of the CSF samples (34% of the patients). CMV was the HV most frequently detected in our patients (25%), while EBV, VZV, HSV, and HHV-6 DNAs were present in significantly fewer cases (7, 4, 3, and 1%, respectively). When results were compared with the final etiological diagnoses of the patients, the multiplex HV PCR showed high specificity for the diagnosis of CMV and VZV neurological diseases and for cerebral lymphoma (0.95, 0.97, and 0.99, respectively). The sensitivity of the assay was high for CMV disease (0.87), was low for cerebral lymphoma (0.33), and was not evaluable for VZV disease due to the small number of patients with this diagnosis. Nevertheless, detection of VZV DNA had possible diagnostic value in four of the nine cases, and EBV DNA amplification always predicted the diagnosis of cerebral lymphoma in patients with cerebral masses. Detection of HSV DNA was frequently associated with CMV amplification and fatal encephalitis. HHV-6 was not considered to have a pathogenetic role in the three cases in which it was detected. This multiplex HV PCR assay is a specific and clinically useful method for the evaluation of HIV-infected patients with neurological disorders related to HV.

Daily energy expenditure in Mexican and USA Pima indians: low physical activity as a possible cause of obesity

BACKGROUND

Obesity is caused by an imbalance between energy intake and energy expenditure. However, it is unknown whether increased physical activity protects susceptible populations against the development of obesity and type 2 diabetes.

OBJECTIVE

To investigate the potential protective role of environment and physical activity against obesity by measuring total energy expenditure in Mexican and USA Pima Indians.

METHODS

We compared the physical activity level of 40 (17 female and 23 male; 37+/-11 y, 66+/-13 kg) Mexican Pima Indians from a remote, mountainous area of Northwest Mexico, with 40 age-and-sex matched (17 female and 23 male; 37+/-12 y, 93+/-22 kg) Pima Indians from the Gila River Indian Community in Arizona, USA. We measured total energy expenditure (TEE) by doubly labeled water and calculated physical activity by different methods: physical activity level (PAL) as the ratio of TEE on resting metabolic rate (RMR), TEE adjusted for RMR by linear regression, activity energy expenditure adjusted for body weight (AEE), and activity questionnaire.

RESULTS

Physical activity was higher in Mexican Pima Indians when compared with USA Pima Indians as assessed by PAL (1.97+/-0.34 vs 1.57+/-0.16, P<0.0001), TEE adjusted for RMR (3289+/-454 vs 2671+/-454 kcal/day, P<0.0001) and AEE adjusted for body weight (1243+/-415 vs 711+/-415 kcal/day, P<0. 0001). Questionnaires revealed more time spent on occupational activities among Mexican Pima compared with USA Pima (23.9+/-13.3 vs 12.6+/-13.9 h/week, P<0.001).

CONCLUSION

These data support a significant role for physical activity in the prevention of obesity in genetically susceptible populations. International Journal of Obesity (2000)24, 55-59

Vitamin A deficiency and low prevalence of anemia in Yaqui Indian children in northwest Mexico

A study of 296 school-age Yaqui Indian children (6-10 y) was conducted in 26 rural communities. Vitamin A status was determined by retinol and carotenoid serum levels according to a method described previously (IVACG, 1982). Serum retinol and carotenoids in children were analyzed according to community size. Vitamin A intake was assessed in a sub-sample by means of a 24 h recall questionnaire. Serum retinol distribution showed that 6.3% of the children were below 10 microg/100 mL (0.35 micromol/L) and 40% were in the range of 10-20 microg/100 mL (0.35-0.70 micromol/L). Differences (p < 0.02) were found between small and large communities (Median, 95% CI): 19.2 (17.1, 20.9) microg/100 mL and 22.9 (20.3, 24.1) microg/100 mL. Serum carotenoid levels were significantly higher in large than in small and medium communities: 72 (68.2, 77.8) microg/100 mL versus 62.4 (53.3, 68.2) and 62.4 (55.7, 69.6) microg/100 mL, respectively. Food staples were wheat flour tortillas, pinto beans, corn tortillas, few animal products and scarce fresh vegetables. Mean vitamin A consumption was 244+/-29 microg RE (34.9% of the US RDA). Iron status showed that only 4 children were classified as anemic, with two of them having iron deficiency anemia. Iron deficient erythropoiesis was observed in 7.8% of the children and iron depletion only in 4.4%. The Yaqui diet seems to provide adequate amounts of iron but not of vitamin A or its precursors, which renders a vitamin A status of sub-clinical deficiency that could be considered a public health problem.

[Anthropometry and body composition in persons over 60. The importance of physical activity]

OBJECTIVE

To measure anthropometric indicators of body composition by electric bioimpedence, as well as physical activity, blood glucose and arterial pressure in rural people over 60 years of age.

MATERIAL AND METHODS

A total of 54 subjects over 60 years old were selected by intentional non-probabilistic sampling. They were subjected to a standardized protocol to measure anthropometric indicators, body composition by electric bioimpedance (EBI), and physical activity was determined by an activity questionnaire. Arterial pressure and glucose tolerance levels were also measured. Analysis included Student's t test to detect differences by sex and the association of physical activity, body composition and other variables by simple linear regression and Pearson's correlation coefficient.

RESULTS

Physical activity correlated negatively with percent fat (r = -0.36; p = 0.007) and diastolic (r = -0.36; p = 0.006) and systolic blood pressure (r = -0.32; p = 0.018), and body mass index with post dose glucose (r = 0.31; p = 0.024).

CONCLUSIONS

Physical activity in this age group may have a favorable impact with respect to the mentioned health indicators.

[Energy requirements in active elderly individuals living in a rural region of Northwest Mexico]

The energy requirements in free-living elderly rural people were investigated by measuring physical activity level and basal energy expenditure using a physical activity questionnaire and indirect calorimetry, respectively. Approximately 65 different occupational and leisure activities over the previous 12 months were considered. Energy expenditure by physical activity was estimated using PAL for specific activities reported in the literature. All 65 the activities were considered to adapt the questionnaire. Reproducibility was evaluated by administering the questionnaire on two separate occasions within 3-4 week elapsed between them. It was found to be reliable for the study (Pearson correlation was r = 0.85; p < 0.05). The physical activity level of the women and men were 1.50 +/- 0.29 and 1.65 +/- 0.66, respectively (p < 0.05). The basal metabolic rate also differed between women and men (p < 0.05) with 5348 +/- 719 kJ/day and 6160 +/- 862 kJ/day, respectively. Similarly the total energy expenditure was different (p < 0.05) in women and men 8311 +/- 1610 kJ/day and 10,210 +/- 2268 kJ/day, respectively. Results indicate that the physical activity questionnaire presented can be an alternative methodology to estimate physical activity in free-living elderly people and together with indirect calorimetry measurements can be useful to estimate their energy expenditure and hence energy requirements.

Plasma leptin concentrations in Pima Indians living in drastically different environments

OBJECTIVE

Plasma leptin, an important signal for the regulation of energy stores, is known to be influenced by many hormonal factors, but may also be affected by behavioral and environmental factors. The purpose of this study was to investigate the impact of lifestyle (diet composition, level of physical activity) on plasma leptin concentrations among Pima Indians living in drastically different environments.

RESEARCH DESIGN AND METHODS

We studied 224 Mexican Pima Indians (115 women, 109 men) living a traditional lifestyle in a remote, mountainous area of northwest Mexico and 418 U.S. Pima Indians (281 women, 137 men) living a North American lifestyle on the Gila River Indian Reservation in Arizona. We hypothesized that the absolute value of leptin would be lower in Mexican Pima Indians because of their lower percent body fat, but could be further influenced by their lifestyle, independent of body composition.

RESULTS

Leptin concentration (enzyme-linked immunosorbent assay [ELISA]) was strongly correlated with percent fat (bioimpedance) in Mexican Pima Indians (r = 0.83, P < 0.0001) and U.S. Pima Indians (r = 0.86, P < 0.0001). Among U.S. Pima Indians, independent of percent fat, subjects with type 2 diabetes had lower leptin than nondiabetic subjects (difference = 6.9 +/- 1.0 ng/ml, P < 0.002). Among nondiabetic subjects, Mexican Pima Indians had lower absolute leptin concentrations than U.S. Pima Indians, but higher after adjustment for percent body fat, waist circumference, age, and sex. In a subset of 70 pairs of subjects matched for sex and percent body fat, leptin concentration was 4.4 +/- 1.0 ng/ml (P < 0.0001) higher in Mexican Pima Indians versus U.S. Pima Indians.

CONCLUSIONS

These results suggest that independent of body composition, leptin concentration may be increased by environmental factors, such as a high-carbohydrate diet and a high level of physical activity.

Is a low leptin concentration, a low resting metabolic rate, or both the expression of the "thrifty genotype"? Results from Mexican Pima Indians

BACKGROUND

The high prevalence of obesity and type 2 diabetes in some populations is believed to be the expression of a "thrifty genotype," which conferred survival advantages during periods of harsh environmental conditions, but has become a liability in industrialized environments of abundance. Low plasma leptin concentrations and a low metabolic rate may be the phenotypic expression of this genotype.

OBJECTIVE

We hypothesized that plasma leptin concentrations and resting metabolic rate would be lower in Mexican Pima Indians not yet exposed to an affluent lifestyle than in non-Pima Mexicans living in the same environment.

DESIGN

We studied 208 nondiabetic Pima Indians (105 women and 103 men) living a traditional lifestyle in a remote, mountainous area of northwest Mexico and 183 nondiabetic non-Pima Mexicans (90 women and 93 men) living in the same environment. A subset of 40 (17 women and 23 men) Pima Indians and 40 (19 women and 21 men) non-Pima Mexicans was selected for studies of energy metabolism with a ventilated-hood system.

RESULTS

Leptin concentrations were strongly correlated with percentage body fat in both groups (r = 0.83, P < 0.0001). There was no significant difference in plasma leptin concentration between groups in absolute value (P = 0.90) or after adjustment for percentage body fat, waist circumference, age, and sex (P = 0.40). Similarly, there was no significant difference in resting metabolic rate between groups in absolute value (P = 0.27) or after adjustment for fat-free mass (P = 0.32).

CONCLUSIONS

These results do not support the hypothesis that hypoleptinemia, a relatively low resting metabolic rate, or both are expressions of the thrifty genotype.

[Effect of supplementation with a massive dose of vitamin A in children 6 to 36 months of age]

OBJECTIVE

To evaluate the impact of a single massive dose of vitamin A on the vitamin and iron status in children of margined urban areas in Hermosillo, Sonora, Mexico.

MATERIAL AND METHODS

A total of 60 children received one dose of 100,000 IU (children from 6 to 12 months) and of 200,000 IU (children from 12 to 36 months) of retinol palmitate distributed by the Health Ministry in June, 1994. Serum levels of retinol, carotenoids, iron, transferrin and ferritin were measured at three periods: basal, after two weeks and after three months.

RESULTS

The mean for retinol basal values was 0.7 mumol/l, after two weeks it was 0.97 mumol/l (p < 0.001) and after three months it was 0.83 mumol/l (p > 0.05). When basal values were measured, 6.3% of the children showed severe vitamin A deficiency, which disappeared in the periods following the supplement; additionally, 42% showed moderate deficiency which had decreased to less than 7% after three months. No differences were found for serum iron and transferrin levels (p > 0.05), however, ferritin levels increased (p < 0.001) after three months indicating an improvement in iron reserves.

CONCLUSIONS

Massive dose distribution may have an important impact on vitamin A and iron status in children.

Visceral leishmaniasis in patients infected with the human immunodeficiency virus

The experience with 52 episodes of visceral leishmaniasis diagnosed in 43 patients is reported. The most common symptoms were fever (81%), splenomegaly (65%), hepatomegaly (63%), and pancytopenia (73%). In 79% of the patients, CD4+ cell counts were < 100 cells/mm3. Prior or simultaneous diagnosis of AIDS was made in 29 (67%) patients. Diagnosis was considered fortuitous in 19% of the episodes. In 27% of the episodes, the diagnosis was made on the basis of demonstration of parasites outside the reticuloendothelial system, chiefly blood (7 cases) and gastrointestinal mucosa (5 cases). Parasites were frequently observed or cultured from blood (22/37 episodes) or the digestive tract (8/9 episodes). High antimony doses were more effective than low doses in achieving clinical or parasitological cure (rate of cure, 80% vs. 40%, p = 0.11). Severe toxicity was observed in six (11.7%) of the 51 treated episodes. Severe AIDS-related diseases [odds ratio (OR) 10, p < 0.05] and CD4+ counts (OR 12, p < 0.05) were independent factors for early death. Prophylaxis with monthly pentamidine was not useful in reducing relapses of visceral leishmaniasis.

[Tuberculous hepatosplenic abscess, human immunodeficiency virus infection and multiresistant tuberculosis]

BACKGROUND

Tuberculosis (TB) with liver and/or spleen abscess (HSA) formation in HIV-positive patients is uncommon.

PATIENTS AND METHODS

One hundred and thirty-seven HIV positive patients with TB were studied from January 93 to June 95. Patients with tuberculous HSA were enrolled in the study. Diagnosis was obtained by recovery of Mycobacterium tuberculosis in clinical specimens and the presence of hypoechogenic lesions in liver and/or spleen.

RESULTS

M. tuberculosis isolates were resistant to some of the usual drugs in 51 patients. Twenty of these patients had HSA (39%) and in 18 patients the antibiotic sensitivity testing showed resistance to isoniazid, rifampin, ethambutol, and streptomycin. The remaining 86 patients had episodes of TB with drug-susceptible microorganism and only three patients had HSA (3%) (p < 0.001). The 23 patients with tuberculous HSA had a mean CD4+ lymphocyte count of 33 x 10(6) cells/L (2-111) and 7 had a previous episode of TB. The abdominal echography showed hepatosplenomegaly in all cases. Abscesses were located at the liver in 12 patients (52%), spleen in 18 (78%) and both organs in 7 (30%). In 16 cases a corticosteroid therapy was indicated. In the 3 patients with susceptible TB and HSA the clinical course was good. The 20 patients with resistant TB died.

CONCLUSION

Abdominal TB in HIV-positive patients and HSA formation appears to be more common in severely immunosuppressed patients, with resistant TB and its mortality rate is high. The response to therapy with antituberculous drugs is slow and sometimes the administration of corticosteroids is necessary for the resolution of symptoms.

[Poor digestion of lactose. Its definition, prevalence in Mexico, and its implications in milk consumption]

We review the studies that have been carried out in Mexico related to prevalence of lactase deficiency. We also describe a study carried out in three regions of Mexico with different consumption of milk (Northern, Central & Southeastern), comprising 960 individuals of ages ranging from 1 to 99 years. They were evaluated in a double blind study in order to determine the prevalence of lactose maldigestion with habitual dosis of milk. Each subject received two treatments: a) 240 or 360 mL of intact milk according to age, and b) the same amount of milk but with the lactose hydrolyzed (> 90% hydrolyzed). The participants were classified as digesters or maldigesters of lactose using the hydrogen breath test. The prevalence of maldigesters was higher in the Central (30%) and Southeastern (22%) regions than in the Northern one (9%, p < 0.01). The prevalence increased with age from 4.5% (< 3 years), 13.6% (3 to 5.9), 20.8% (6 to 12.9), 21.8% (13 to 17.9) and 32.9% in adults. Lactose maldigestion affected consumption marginally.

[Lactose intolerance. Its definition, its prevalence in Mexico, and its implications in milk consumption]

In this document we describe some aspects of lactose and milk intolerance, discuss the results of studies carried out previously in Mexico, and report an investigation whose objective was to quantify the impact of lactose intolerance on the habitual consumption of milk in an open population. The prevalence of lactose intolerance and its effect on the consumption of milk was studied in three regions of Mexico. The design of the study was prospective, randomized, double-blind and crossover. The presence of milk intolerance was investigated in 960 subjects with ages between 6 months and 99 years who, as a function of age, received 240 or 360 mL of intact milk and the same amount of hydrolyzed milk. We quantified the consumption of milk and the presence of symptoms after ingesting the tested milk. Seven percent manifested symptoms with the intact milk but only 2% with the hydrolyzed milk (p < 0.001). The presence of symptoms in the intolerant subjects was significantly associated with a lower consumption of milk in comparison with the tolerant individuals (p < 0.001). On the other hand, the consumption of milk appeared to be only marginally associated with the intolerance and its symptoms. We conclude that lactose intolerance does not appear to be a major factor in determining milk consumption in Mexican healthy populations.

[HIV infection and lymphomatous meningitis]

Lymphomatous meningitis and lymphoma confined to the central nervous system are the most serious neurological diseases in patients with human immunodeficiency virus infection. The diagnosis is difficult and it is usually done with advanced systemic disease or when the chemotherapy is finished. During a ten month period, three patients with lymphomatous meningitis and HIV infection were diagnosed in an Infectious Diseases Unit. In one patient, was the initial clinical manifestation of Burkitt's lymphoma and in another, the diagnosis was concomitant with the neoplasm. In the last one, there was a meningeal recidiva afterwards he had received chemotherapy and, theoretically, cured his systemic lymphoma. Clinical, cytologic, immunologic and evolutive study of these three patients is done. It is discussed the meningeal prophylaxis usefulness with intrathecal chemotherapy.

[Colony-stimulating factors and HIV-related neoplasms]

OBJECTIVE

it is analyzed a group of patients with HIV related malignancy treated with myelosuppressive therapy with granulocyte colony stimulating factor (G-CSF) to study the efficacy of hematopoietic growth factors in these subjects.

PATIENTS AND METHODS

it was studied the clinical and hematological evolution of 20 patients with HIV related malignancy treated with standard dose of chemotherapy and 5 micrograms/Kg/day of G-CSF starting 24 hours after the completion of chemotherapy administration. It was done an epidemiological study and was determined haemoglobin level, and the number of leukocytes, monocytes, neutrophils, lymphocytes, CD4+ lymphocytes and platelets before and after the chemotherapy administration.

RESULTS

all of the patients were men with mean age of 37 +/- 2 years. The mean of lymphocyte CD4+ count was 17 x 10(6)/l and the tumor was the first aids manifestation in 50% of the subjects. The mean days of hospitalization was 14 +/- 3 days. As the result of the G-CSF administration, the leucocyte and the neutrophil count was statistically elevated (p < 0.01) and the platelets, the lymphocytes and the monocytes were not statistically elevated. Only one patient had a severe adverse reaction. Seventeen patients (85%) are dead, but only in 3 the cause was an infectious disease.

CONCLUSION

the use of G-CSF prophylactically can elevate the neutrophil count and avoid the apparition of febrile neutropenia in patients with HIV related malignancies.

Colon cancer in rats and diet in the Sonoran desert region of Mexico

The role of dietary fiber in colon cancer is still not clear. Epidemiological studies suggest a protective role for high fiber intake. However the data suggest that the effects of fiber must be considered in the context of the total diet and its interactions with other dietary components. The typical Sonora diet is high in dietary fiber (7.8%) and the majority of this fiber (71%) is insoluble. Comparing the incidence of colon cancer in Sonora with its neighboring state of Arizona, in 1991, Sonora reported 40 cases of colon cancer, a population of 1,823,606, compared to 1432 for Arizona (3,763,322 inhabitants). The typical regional diet was evaluated for its protective effect in the development of colon cancer in rats injected with azoxymethane, AOM. The regional diet showed a tendency to protect against colon cancer, an incidence of 45% compared to 66% for the control diet, although this effect was not significant (p = 0.15). Further studies are needed to fully evaluate the diet and certain interactive dietary factors such as fat, quantity as well as type, protein, calcium and antioxidant nutrients.

[Chemical composition, dietary fiber and mineral content of frequently consumed foods in northwest Mexico]

Nutrient composition in foods is very important specially in evaluation of nutritional status in populations. In this study the proximate composition, dietary fiber (DF) and mineral content of 15 frequently consumed foods in Northwest Mexico were determined. The procedures used were AOAC (1984) official methods, chemical-enzymatic method for DF and atomic absorption spectrophometry for minerals. Foods were grouped into cereals, legumes, meat and dairy products, fat was the most variable component in all foods (0,41 to 21,1 g/100 g). Fired beans (Phaseolus vulgaris: variedad pinto) had the highest DF content (9,21 g/100g); as is basis). Sodium among the minerales was also highly variable mainly due to the addition of salt during preparation of foods, except in corn tortillas were salt is not added. In contrast wheat flour tortillas had the highest sodium content of the foods analysed. Fresh white cheese had the highest calcium content (563 mg/100g). The meat group had the highest content of Fe and Zn (2,4-5,4 and 4,2-5,4 mg/100 g respectively). This study has provided information with current analytical techniques of important foods in northwest Mexico that will contribute to food composition tables in Latin America.

Energetic consequences of mild Giardia intestinalis infestation in Mexican children

This study explored the effects of mild infestation with Giardia on energy intake and expenditure at rest and in activity in an urban Mexican population. Ten boys aged 6-10 y living in low-income sectors in northwest Mexico who had Giardia infestation were recruited. Energy intake, basal metabolic rate (BMR), and total free-living expenditure (TEE) measured by the doubly labeled water method were determined for 7 d during both infestation and after treatment. There was no significant difference in recorded energy intake between the two periods (7.76 and 7.70 MJ/d; P = 0.847). BMR showed no significant change in response to treatment; values were 4.79 and 4.86 MJ/d (P = 0.03). The mean TEE increased by almost 1 MJ/d in the Giardia-free period. This increase was observed in 8 of the 10 subjects; however, the overall change was not statistically significant (P = 0.08).