Human intestinal protozoa in fresh asparagus from different types of markets in northwest Mexico.

Caborca is one of the most productive asparagus-growing regions in the state of Sonora in northwest Mexico, an area where some fresh fruits and vegetables are sold at unregulated open-air street markets. This is a cross-sectional study in which fifty bundles of asparagus for exportation, 50 bundles of sub-standard asparagus, and 50 bundles of asparagus from open-air markets were selected randomly and then subjected to Faust, Kinyoun and ELISA testing to detect intestinal parasites. Pearson's chi-square (χ2) and Student-NewmanKeuls tests were used to estimate differences among the sampling site groups (P < 0.05). The pathogens Cryptosporidium spp. (29%) G. intestinalis (5%) and Cyclospora spp. (3%) were found in the asparagus sold in the region. The prevalence of Cryptosporidium spp. was higher in both the sub-standard asparagus and the product sampled from the open-air markets than in the samples for exportation (P < 0.05). This is the first study to demonstrate contamination by intestinal parasites in asparagus sold in different markets in northwest Mexico.

Membrana de Quitosano con Aceites Esenciales de Romero y Árbol de Té: Potencial como Biomaterial / Membrane of chitosan with essential oils of Romero and Tree of Tea: Potential as biomaterial

RESUMEN: El quitosano (CH) tiene propiedades hemostáticas, cicatrizantes y estimulantes del sistema inmune del hospedero contra infecciones virales y bacterianas. Además es biodegradable, no tóxico, antimicrobiano, biocompatible y filmogénico. Estas propiedades han sido utilizadas para acarrear y liberar compuestos bioactivos para sus posibles usos en la salud humana. Por otro lado, los compuestos bioactivos como los aceites esenciales de gran volatilidad como romero (RMO) [Rosmarinus officinalis] y árbol de té (TTO) [Melaleuca alternifolia], pueden ser alternativa importante de uso como antioxidantes y antimicrobianos que podrían inducir cambios favorables en la membrana de CH. Por lo tanto, se incorporaron aceites esenciales de TTO y RMO (0.25, 0.50 y 1.00% v/v) en membranas de CH por el método de casting y se evaluaron su solubilidad, PVA, transparencia y capacidad de bloqueo de la luz ultravioleta, capacidad antioxidante y de protección del eritrocito humano. RMO y TTO redujeron la solubilidad (28-58%) y PVA (entre 28-58%) de las membranas de CH. Todas las membranas fueron amarillas, ligeramente opacas y con capacidad de bloquear la luz ultravioleta. También, las membranas mostraron relativa baja capacidad antioxidante por el radical ABTS (≈ 6 at 9 %), pero con excelente efecto protector sobre el eritrocito humano (> 63 %).

ABSTRACT: Chitosan (CH) has hemostatic properties and accelerated healing ability to stimulate the host immune system against viral and bacterial infections. It is also biodegradable, nontoxic, antimicrobial, biocompatible, and capable of forming membranes and to carry and to release bioactive compounds. These properties of CH can be useful to carry some volatile essential oils having bioactive compounds (antioxidants and antimicrobials) with potential application in human health as those as rosemary (RMO) [Rosmarinus officinalis] and tea tree (TTO) [Melaleuca alternifolia]. These essential oils were incorporated into the chitosan by the casting method in this study. The physical properties (solubility, PVA, transparency and blocking ultraviolet light) of these membranes with TTO and RMO (0.25, 0.50 and 1.00% v/v), antioxidant capacity and protection human erythrocyte were evaluated. TTO and RMO reduced solubility (28-58%) and PVA (between 28-58%) of CH membranes. All membranes were yellow, slightly opaque and they were able to block the ultraviolet light. Membranes also showed relatively low antioxidant capacity by the radical ABTS (≈ 6 at 9%), but it was accompanied by an excellent protective effect on the human erythrocyte (> 63%).

Efecto de Microemulsiones de Aceites Esenciales Sobre el Eritrocito Humano y Bacterias Patógenas / Effect of Microemulsions of Essential Oils on Human Erythrocyte and Pathogens Bacteria

RESUMEN: El objetivo del presente trabajo fue evaluar el efecto de las microemulsiones de aceite esencial de romero (AER) y árbol de té (AET) sobre el eritrocito humano y microorganismos patógenos. Para ello, se elaboraron microemulsiones de AER y AET al 8.0% (v/v), 5.0% (v/v) y 2.5% (v/v). Las microemulsiones fueron probadas sobre el eritrocito humano para determinar el porcentaje de hemólisis, el porcentaje de inhibición de hemólisis y su actividad antibacterial contra E. coli O157:H7 y S. aureus. Las microemulsiones con AER no presentaron actividad hemolítica significativa, caso contrario con las microemulsiones de AET al 8.0% (≈70%) y 5.0% (33%) que presentaron mayor actividad hemolítica. Las microemulsiones de AER protegieron significativamente al eritrocito contra la presencia de radicales libres, en comparación con aquellas de AET (p< 0.05). Además, las emulsiones de AET al 8.0% mostraron efectos antibacterianos contra E. coli O157:H7 y S. aureus mientras que AER al 8.0% solo mostraron efecto contra E. coli O157:H7. La limitante del estudio fue que no utilizamos células nucleadas para establecer si los aceites esenciales dañan el material nuclear. Sin embargo, observamos que el tipo y la cantidad de aceite utilizado pueden tener implicaciones serias sobre la membrana eritrocitaria. Se concluye que las microemulsiones de AER presentaron mejor efecto protector eritrocitario, mientras que las microemulsiones de AET presentaron mejor actividad antibacterial contra las bacterias estudiadas, pero con mayor efecto tóxico sobre el eritrocito.

ABSTRACT: The aim of the study was to evaluate the effect of microemulsions of rosemary (AER) and tea tree (AET) essential oils on human erythrocyte and pathogen bacteria. Microemulsions of each oil were prepared at 8.0% (v/v), 5.0% (v/v) and 2.5% (v/v), and they were tested on human erythrocyte to determine the hemolysis percentage, hemolysis inhibition percentage and the antibacterial capacity against E. coli O157:H7 and S. aureus. All AER microemulsions showed no significant hemolytic activity. On the contrary, AET microemulsions showed hemolytic effect but those in concentrations of 8.0% (≈70 %) and 5.0% (33%) showed the highest effect. In addition, AER microemulsions showed protective effect against free radicals in comparison with the AET microemulsions (p< 0.05). On the other hand, the AET microemulsion at 8.0% showed antibacterial effect against E. coli O157:H7 and S. aureus, and the AER at 8.0% showed antibacterial effect against E. coli O157:H7. The limitation of this study was that nucleated cells were not used to observe the damage of the essential oils on nuclear material. However, the observed damage of erythrocyte's membrane is depending on type and amount of used oil. Therefore, it can be concluded that the AER microemulsions showed better protective effect of erythrocytes, while AET microemulsions showed better antibacterial effect against the tested bacteria, although with toxic effect on the erythrocytes.

Trichuriasis and low-iron status in schoolchildren from Northwest Mexico.

BACKGROUND/OBJECTIVES: The aim of this study was to investigate the association between trichuriasis and iron status in rural schoolchildren from Northwest Mexico. SUBJECTS/METHODS: A total of 73 schoolchildren (37 boys, 36 girls) between the ages of 6 and 10 years were voluntarily recruited from the public primary school of the rural community of El Higueral in Culiacan, Sinaloa (Northwest Mexico) for a cross-sectional study with a longitudinal follow-up of 5 weeks. Data were collected on socioeconomic status, anthropometry, haematological and biochemical indices of iron status, daily iron intake, and prevalence and intensity of trichuriasis. Multiple regression models, independent t-test and paired t-test were used to analyse the association between trichuriasis and iron status in cross-sectional and longitudinal samples, respectively. Adjusted models were tested for linear regression assumptions using residual plots. RESULTS: The mean age of the Trichuris-free and Trichuris-infected groups was 7.7±1.3 and 7.7±1.5 years respectively (P=0.92). The height for age was significantly higher in the Trichuris-free group than the Trichuris-infected group (P=0.02). No differences were found in the socioeconomic variables between the two groups. At baseline, significantly higher concentrations of haemoglobin, haematocrit, blood cell count (RBC) and serum iron were measured in the Trichuris-free group compared with the Trichuris-infected children (P<0.05). An association was found between trichuriasis and haemoglobin adjusted for socioeconomic variables, age and sex. Haemoglobin, RBC and serum ferritin concentrations were significantly increased in the infected children 5 weeks after treatment (P<0.05). CONCLUSIONS: Trichuriasis could be a risk factor for low-iron status in the schoolchildren of Northwest Mexico.

Impact of Giardia intestinalis on vitamin a status in schoolchildren from northwest Mexico.

We conducted a cross-sectional study in northwest Mexico in order to investigate the association between giardiasis and serum vitamin A in 40 Giardia-infected and 70 Giardia-free schoolchildren who were covered by a regional school breakfast program. There were no significant differences in age, Z-scores for nutritional indices of height for age, weight for age, or weight for height, socioeconomic conditions (employment and education of the parents, household conditions, sanitation facilities, type of drinking water, and family income), and mean daily intakes of vitamin A in the Giardia-free (899 +/- 887 microg) and the Giardia-infected (711 +/- 433 microg) groups. A higher concentration of serum retinol was found in the Giardia-free group than in the Giardia-infected group (0.75 micromol/L versus 0.61 micromol/L, respectively; p < 0.0001). Giardia-infected children were more likely to be vitamin A-deficient than the Giardia-free children (OR = 3.2; 95% CI = 1.2-8.5). Although 95% of the children met the daily-recommended intakes of vitamin A, half of them showed subclinical vitamin A deficiency. It is recognized that vitamin A deficiency is multifactorial and giardiasis was a factor significantly associated with this deficiency in this study. Mexican program developers and policymakers should be aware about the distinction between dietary deficiencies and deficiency diseases when current national program strategies for parasitic control and vitamin A supplementation are redesigned.

Prevalence and intensity of intestinal parasitic infections in relation to nutritional status in Mexican schoolchildren.

Undernutrition and intestinal parasitic infections affect childhood development and morbidity in many developing countries. Undernutrition may increase susceptibility to parasitic infections which in turn impair the nutritional status of the host. The relationship between intestinal parasitic infections and nutritional status in 400 Mexican schoolchildren was investigated. More than half of the children in the study showed intestinal parasites and polyparasitism. The prevalence of helminth infections was significantly higher in Oaxaca than in Sinaloa (P < 0.05). Z scores for weight-for-age (WA) and height-for-age (HA) were much lower in children of Oaxaca than in Sinaloa (P < 0.001). A significantly higher Z score for weight-for-height (WH), WA, and HA were found in non-infected versus infected children (P < 0.05). Higher prevalences of intestinal infections were found in children with lower HA and WA than in normally nourished children (P < 0.05). Higher intensities of Ascaris lumbricoides and Trichuris trichiura were found in the schoolchildren of Sinaloa than in Oaxaca (P < 0.01). Negative and significant associations were found between Hymenolepis nana and T. trichiura infection (eggs per gram) and nutritional status. Intestinal parasitic infections may be regarded as main risk factors associated with poor nutritional status in Mexican schoolchildren.

[Effect of supplementation with a massive dose of vitamin A in children 6 to 36 months of age]. / Efecto de la suplementación con una dosis masiva de vitamina A en niños de 6 a 36 meses de edad.

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.