Association of vitamin D receptor polymorphisms with osteoporosis in mexican postmenopausal women

It has been reported that Vitamin D receptor polymorphisms are associated with osteoporosis, particularly those demonstrated by the BsmI and FokI restriction enzymes. Herein we report the results of a case-control study performed in postmenopausal Mexican women. We studied 65 osteoporotic women (< or = -2.5 SD bone mineral density [BMD] of young normal females) and 57 controls (over 90% > or = -1.5 SD BMD of young normal females. Restriction enzymes BsmI and FokI were used to identify polymorphisms. Odds ratios and their 95% confidence intervals were calculated, and analysis was performed controlling for age as a covariate. The BsmI genotypes revealed a higher frequency of the bb genotype in cases than in controls, contradicting much of the literature that suggests this genotype protects females against osteoporosis. Regarding the FokI genotypes, we were unable to confirm that the FF genotype has a protective effect against osteoporosis. The inconsistencies found in the literature and the results obtained in the present work suggest to us that other genetic and nongenetic factors are involved in the occurrence of osteoporosis, confounding the results of the possible association of osteoporosis and VDR polymorphisms.     

The disposition of nifurtimox in the rat isolated perfused liver: effect of dose size

The disposition of nifurtimox was studied in the rat isolated perfused liver using a recirculating system. The drug was administered as a bolus (5.0, 15.0 or 30.0 micrograms mL-1), and its disappearance was monitored by analysing perfusate samples. In all experiments perfusate disappearance was monoexponential, and no significant difference was found between the three doses for the elimination constant (0.016, 0.011 and 0.012 min-1, respectively), half-life (46.6, 65.8 and 66.8 min, respectively), extraction rate (0.128, 0.091 and 0.099, respectively) and distribution volume (41.1, 47.3 and 30.7 mL g-1, respectively). At 30 micrograms mL-1 the hepatic clearance was lower than the other concentrations of nifurtimox (0.66, 0.51 and 0.34 mL min-1 g-1, respectively). Relatively little parent drug was recovered from the liver at the end of the perfusions. In summary, nifurtimox is cleared slowly from the rat isolated perfused liver, is poorly extracted by hepatocyte cells and is completely metabolized from 2 to 4 h after perfusion.     

Dynamics of Indigenous Microbial Populations of Butter Head Lettuce Grown in Mulch and on Bare Soil

ABSTRACT:  The native microflora of lettuce cultivated in mulch and on bare soil and its evolution during storage at optimal condition were evaluated. Inner, mid, and outer leaves of the lettuce heads were analyzed separately and the evolution of the microbial populations were fitted to Gompertz and logistic models. The cultivation method (bare soil and mulch) introduced differences in the initial counts, evolution, and tolerance to refrigeration temperatures for some of the microbial populations under study. Most microbial populations from mulch lettuce presented a decline or little growth under refrigerated storage. However, populations from bare soil lettuce presented some growth phase during storage. Lactic acid bacteria from bare soil lettuce presented significant growth after 8 d of storage while LAB from mulch grown lettuce did not. Concurrently with the LAB growth, there was a decline in the coliform counts in bare soil grown lettuce. At the end of storage, the inner and mid leaves of mulch lettuce presented lower counts of psychrotrophic bacteria, LAB, and yeast and molds.     

High-Quality GaN heteroepitaxial films grown by metalorganic chemical vapor deposition

In this paper, we describe the growth and characterization of high-quality GaN heteroepitaxial films grown on basal-plane sapphire substrates using metalorganic chemical vapor deposition. The quality of these films is analyzed by a variety of methods, including high-resolution x-ray diffraction, optical transmission spectroscopy, transmission electron microscopy (TEM), room temperature photoluminescence, and room-temperature Hall measurements. The x-ray diffraction full width at half maximum value of ΔΘ ～37 arc s is the narrowest reported to date for any III-V nitride film on any substrate. The x-ray rocking curves for ～0.48 μm thick GaN/Al₂O₃ heteroepitaxial layers exhibit Pendellösung fringes, indicating that even relatively thin films can be of high quality. High-resolution TEM lattice images further attest to the excellent structural quality, showing the films to be completely free of stacking faults. Furthermore, no evidence of columnar growth is observed.     

Computing exact aspect graphs of curved objects: Algebraic surfaces

This article presents an algorithm for computing the exact aspect graph of an opaque solid bounded by a smooth algebraic surface. Orthographic projection is assumed. The algorithm is based on a catalog of visual events available from singularity theory. It uses curve tracing, cell decomposition, homotopy continuation, and ray tracing to construct the regions of the view sphere delineated by visual-event curves. The algorithm has been fully implemented, and examples are presented.     

Analysis of the predictive value of clinical data in patients with suspected colonic disease

OBJECTIVE: To develop guidelines for predicting colonic disease on the basis of clinical parameters. EXPERIMENTAL DESIGN: A prospective study of the clinical data prior to colonoscopy. On the basis of the endoscopic findings, the patients were divided into three diagnostic groups: absence of significant disease, significant benign disease and malignant disease. The patient population was divided randomly into two subgroups. The clinical data from one of them was used to build a database which, using Bayes' theorem, was compared with the variables from the other subgroup to predict the diagnosis for each patient. PATIENTS: A total of 336 patients (170 males and 166 females; mean age: 58 years; range: 15 to 87 years) were evaluated. RESULTS: When the endoscopic findings were grouped on the basis of their clinical importance, 211 patients (63%) belonged to the group without significant disease, 60 patients (18%) had significant benign disease and 65 (19%) presented a neoplastic disease. Of the 21 variables selected for use in the database, 6 showed statistically significant differences in terms of the absence or presence of malignant disease: age, absence of previous similar episodes, weight loss, rectal bleeding, lack of improvement and the presence of a mass on digital rectal examination. The predictive model differentiated patients with neoplasm from those without malignant disease, but was not capable of identifying differences among the latter. The model was useful for assessing the risk of malignant disease for each patient. CONCLUSIONS: The predictive model obtained is a useful tool for establishing the diagnosis and the priority in the performance of colonoscopy.