Francisco González-Salazar

Sharply higher rates of iron deficiency in obese Mexican women and children are predicted by obesity-related inflammation rather than by differences in dietary iron intake

BACKGROUND Obese individuals may be at increased risk of iron deficiency (ID), but it is unclear whether this is due to poor dietary iron intakes or to adiposity-related inflammation. OBJECTIVE The aim of this study was to examine the relations between body mass index (BMI), dietary iron, and dietary factors affecting iron bioavailability, iron status, and inflammation [C-reactive protein (CRP)] in a transition country where obesity and ID are common. DESIGN Data from the 1999 Mexican Nutrition Survey, which included 1174 children (aged 5-12 y) and 621 nonpregnant women (aged 18-50 y), were analyzed. RESULTS The prevalence of obesity was 25.3% in women and 3.5% in children. The prevalence of ID was significantly (P < 0.05) higher in obese women and children compared with normal-weight subjects [odds ratios (95% CIs): 1.92 (1.23, 3.01) and 3.96 (1.34, 11.67) for women and children, respectively]. Despite similar dietary iron intakes in the 2 groups, serum iron concentrations were lower in obese women than in normal-weight women (62.6 ± 29.5 compared with 72.4 ± 34.6 μg/dL; P = 0.014), and total-iron-binding capacity was higher in obese children than in normal-weight children (399 ± 51 compared with 360 ± 48 μg/dL; P < 0.001). CRP concentrations in obese women and children were 4 times those of their normal-weight counterparts (P < 0.05). CRP but not iron intake was a strong negative predictor of iron status, independently of BMI (P < 0.05). CONCLUSIONS The risk of ID in obese Mexican women and children was 2-4 times that of normal-weight individuals at similar dietary iron intakes. This increased risk of ID may be due to the effects of obesity-related inflammation on dietary iron absorption. Thus, ID control efforts in Mexico may be hampered by increasing rates of adiposity in women and children.

In vitro activity of Tridax procumbens against promastigotes of Leishmania mexicana.

ETHNOPHARMACOLOGICAL RELEVANCE Tridax procumbens is an active herb against leishmaniasis. AIM OF THE STUDY Leishmaniasis is a group of diseases caused by Leishmania protozoa. We investigated the antileishmanial activity of Tridax procumbens extracts and a pure compound against promastigotes of Leishmania mexicana, the causative agent of cutaneous leishmaniasis in the New World. MATERIALS AND METHODS Extracts and (3S)-16,17-didehydrofalcarinol (1) were obtained by chromatographic methods from Tridax procumbens, and the latter identified by spectroscopic analysis. The effect of these extracts and 1 on the growth inhibition of promastigotes of Leishmania mexicana was evaluated. In order to test the safety of extracts and 1, mammalian cells were treated with them, and cell viability was assessed using trypan blue and MTT. RESULTS We demonstrated that extracts of Tridax procumbens and 1 showed a pronounced activity against Leishmania mexicana. The methanol extract inhibited promastigotes growth of Leishmania mexicana with a 50% inhibitory concentration (IC(50)) of 3 microg/ml, while oxylipin 1 exhibited the highest inhibition at IC(50)=0.478 microg/ml. CONCLUSIONS In this study we report the biological activity of extracts and (3S)-16,17-didehydrofalcarinol (1), obtained from Tridax procumbens, on the promastigote form of Leishmania mexicana, with no effect upon mammalian cells.

TRICHOMONAS VAGINALIS: IDENTIFICATION OF SOLUBLE AND MEMBRANE-ASSOCIATED PHOSPHOLIPASE A1 AND A2 ACTIVITIES WITH DIRECT AND INDIRECT HEMOLYTIC EFFECTS

A direct hemolytic activity, dependent on phospholipase A (PLA) activity, was located in the particulate subcellular fraction (P30) of Trichomonas vaginalis. We identified soluble direct and indirect hemolytic activities in the spent medium and soluble fraction (S30) of T. vaginalis strain GT-13. Spent medium showed the highest specific indirect hemolytic activity (SIHA) at pH 6.0 (91 indirect hemolytic units [HU]/mg/hr). Spent medium and P30, but not S30, showed direct hemolytic activity. PLA activity was protein dose dependent and time dependent. The highest PLA activity was observed at pH 6.0. All trichomonad preparations showed phospholipase A1 (PLA A1) and phospholipase A2 (PLA A2) activities. Indirect and direct hemolytic activity and PLA A1 and PLA A2 diminished at pH 6.0 and 8.0 with increasing concentrations of Rosenthals inhibitor. The greatest effect was observed with 80 μM at pH 6.0 on the SIHA of S30 (83% reduction) and the lowest at pH 8.0, also on the SIHA of S30 (26% reduction). In conclusion, T. vaginalis contains particulate and soluble acidic, and alkaline direct and indirect hemolytic activities, which are partially dependent on alkaline or acidic PLA A1 and PLA A2 enzymes. These could be responsible for the contact-dependent and -independent hemolytic and cytolytic activities of T. vaginalis.

TRICHOMONAS VAGINALIS: IDENTIFICATION OF A PHOSPHOLIPASE A–DEPENDENT HEMOLYTIC ACTIVITY IN A VESICULAR SUBCELLULAR FRACTION

Trichomonad total extracts (TTE), or vesicular (P30) and soluble (S30) subcellular fractions from 3 pathogenic Trichomonas vaginalis strains (GT-3, GT-13, and GT-15), lysed both human and Sprague–Dawley rat erythrocytes in a time- and dose-dependent manner. The entire hemolytic activity of TTE was located in P30, showing 2 peaks of maximum activity, one at pH 6.0 and another at pH 8.0, in the presence of 1 mM Ca2+. Hemolytic activity on rat erythrocytes was greater at pH 6.0 (6.71 ± 0.33 hemolytic units [HU]/mg/hr to 11.60 ± 0.24 HU/mg/hr) than at pH 8.0 (3.81 ± 0.30 HU/mg/hr to 5.75 ± 0.65 HU/mg/hr), and it was greater than that on human red blood cells at pH 6.0 (2.67 ± 0.19 HU/mg/hr to 4.08 ± 0.15 HU/mg/hr) or pH 8.0 (2.24 ± 0.09 HU/mg/hr to 2.81 ± 0.06 HU/mg/hr). The alkaline and acidic hemolytic activity diminished (60–93% at pH 6.0 and 78–93% at pH 8.0) by the effect of 80 μM Rosenthals inhibitor, which also inhibited 27–45% and 29–54% trichomonad alkaline and acidic phospholipase A activities, respectively. Vesicles, vacuoles, and hydrogenosomes were rich in P30. Trichomonas vaginalis has a hemolytic PLA, which could be involved in its cytopathogenic mechanism.

Mg2+, Mn2+, and Co2+ Stimulate Entamoeba histolytica to Produce Chitin-like Material

The mechanism of Entamoeba histolytica cyst cell wall synthesis is not well understood. Previous research has shown that cystlike structures formed in the presence of chitin synthase cofactors (Mg2+, Mn2+, and Co2+) resist 1% sodium dodecyl sulfate lysis (RCLS), whereas those formed in the absence of cofactors (CLS) do not, and trophozoites are immediately destroyed. This suggests that E. histolytica is able to synthesize chitin, initiating a differentiation process under axenic conditions. To test this hypothesis, polysaccharide hydrolysates from E. histolytica trophozoites, CLS, or RCLS were analyzed with high-performance liquid chromatography. The major components found in all 3 preparations were N-acetylglucosamine (NAG) and glucose (GLC), with RCLS possessing 129 and 180 times more NAG and 2.4 and 2.0 more GLC than trophozoites and CLS, respectively. After 36 hr of incubation with chitinase (16 U/ml) in a hypotonic medium (50 mOsm/kg), 68% of RCLS was lysed, and 100% lost affinity for calcofluor white M2R. The RCLS polysaccharides bound wheat germ agglutinin and appeared as long and thin or short and thick fibers. Accordingly, Mg2+, Mn2+, and Co2+ stimulated E. histolytica to synthesize a chitin-like material.

Snapshot of Quantiferon TB gold testing in Northern Mexico

Most people infected with Mycobacterium tuberculosis have an asymptomatic condition named latent tuberculosis. These people do not have bacilli in the corporal secretions and are hard to diagnose by conventional laboratory tests. Diagnosis of latent tuberculosis infection (LTBI) in México is based on the tuberculin skin test (TST). This test has disadvantages, principally because the vaccine containing the Bacille Calmette-Guérin (BCG) is applied to 99% of this population and causes false positive TST outcomes. Recently, interferon-gamma release assays (IGRA) have been demonstrated to be a good test to detect latent tuberculosis with equal or better sensitivity to TST and without interference from BCG. However, in México the IGRA are an uncommon test due to the higher cost compared to TST. The main objective of this work was demonstrate the potential utility of the Quantiferon TB(®) gold in tube (QTB(®)-GIT) test to detect latent TB in a population from northern México. Samples from 106 subjects with close contact, or without contact, with actively infected TB patients were tested to detect LTBI. Our results show a significant difference between individuals in close contact with active TB patients (39.7%) compared to those without contact (3.2%), p < 0.01. The concordance between TST and QTB(®)-GIT was poor (κ = 0.31). Our preliminary results show that the QTB(®)-GIT has better capacity than TST to detect latent tuberculosis infection.

Environmental tobacco smoke and pneumonia in children living in Monterrey, México

OBJECTIVE Acute respiratory diseases occupy the first 5 places in infantile morbidity and mortality around the world, two million children directly dying from such cause annually. Environmental tobacco smoke (ETS) contains toxic and irritating compounds having an injurious effect on health, producing increased risk of morbidity and mortality in non-smoking adults and children. Our main objective was determining the association between ETS and pneumonia in children. MATERIAL AND METHODS This was an unmatched case and controls hospital-based study. Odds ratio (OR) and 95% confidence interval (CI) were calculated. RESULTS A total of 285 patients (142 cases and 143 controls) were studied; 47,4 % of the patients were female and average age was 4,5,+2,7. OR for patients being exposed to ETS developing pneumonia was 3,44 (CI: 2,11-5,6). DISCUSSION Children being exposed to ETS increases the risk of developing pneumonia by more than threefold.

Interferon Gamma-Based Detection of Latent Tuberculosis Infection in the Border States of Nuevo Leon and Tamaulipas, Mexico.

Nearly one-third of the world’s population is infected with latent tuberculosis (LTBI). Tuberculosis (TB) rates in the border states are higher than national rates in both the US and Mexico, with the border accounting for 30% of total registered TB cases in both countries. However, LTBI rates in the general population in Mexican border states are unknown. In this region, LTBI is diagnosed using the tuberculin skin test (TST). New methods of detection more specific than TST have been developed, although there is currently no gold standard for LTBI detection. Our objective is to demonstrate utility of the Quantiferon TB gold In-Tube (QFT-GIT) test compared with the TST to detect LTBI among border populations. This is an observational, cross-sectional study carried out in border areas of the states of Nuevo Leon and Tamaulipas, Mexico. Participants (n = 210) provided a TST and blood sample for the QFT-GIT. Kappa coefficients assessed the agreement between TST and QFT-GIT. Participant characteristics were compared using Fisher exact tests. Thirty-eight percent of participants were diagnosed with LTBI by QFT-GIT. The proportion of LTBI detected using QFT-GIT was almost double [38% (79/210)] that found by TST [19% (39/210)] (P < 0.001). Concordance between TST and QFT-GIT was low (kappa = 0.37). We recommend further studies utilizing the QFT-GIT test to detect LTBI among border populations.

Age estimation of teenagers from Monterrey (Mexico) by the evaluation of dental mineralization after multi-slice helical computed tomography

Current social conditions require more accurate methods to determine the age of people, either living or deceased. The aim of this study was to determine chronological age by measuring the mineralization of third molars. Volunteers (n = 137), aged between 14 and 22 years and of either gender, were recruited from north-eastern Mexico. Sampling was probabilistic and at random. The mineralization stage of third molars was evaluated with the use of multi-slice helical computed tomography and the Mincer-modified Demirjian amended scale. The correlation coefficient, mean difference and linear estimation were determined. There was a linear correlation between age and the mineralization of third molars. Third molars of adults had a degree of mineralization above Demirjian stage F, whereas the third molars of minors had stages between A and F. Hence, a method was obtained to determine the chronological age from the evaluation of dental mineralization of third molars by multi-slice helical tomography. These results are useful as a diagnostic support in forensic dentistry.

Modified PEHPS Medium as an Alternative for the In Vitro Culture of Giardia lamblia

Commercial culture media present interlot variations in biological activity. We have previously designed a homemade and economic culture medium, PEHPS medium, for the axenic cultivation of Entamoeba histolytica and Trichomonas vaginalis. Trophozoites of amoebae and trichomonads grow well in this medium. Furthermore, the medium is stable for several months when stored frozen or refrigerated. The objective of this work was to modify PEHPS medium to support the in vitro growth of Giardia lamblia. Inocula of 5 × 103 trophozoites/mL of G. lamblia were incubated at 36.5°C in modified PEHPS or TYI-S-33 medium. Then, the growths of the three Giardia strains in both media were compared. The logarithmic growth phase lasted 72 h; the mean yield of the strains ranged from 10.06 to 11.43 × 105 Giardia trophozoites/mL, and the range of duplication time in the three strains was from 5.67 to 6.06 in modified PEHPS medium. These growth characteristics were not significantly different from those obtained with TYI-S-33 medium. We conclude that modified PEHPS medium might be used for the axenic cultivation of G. lamblia.