Activation of the ras family gene has been implicated in colorectal tumorigenesis, K-ras being the most frequently altered gene. The frequency of K-ras codon 12, 13 and 61 point mutations in patients with colorectal neoplasias was examined. We employed a polymerase chain reaction-restriction fragment length polymorphism assay and single-strand conformational polymorphism to detect mutations. We found that point mutations at codons 12 and 13 were present in 53% and 39% of the tumors, respectively, but none at codon 61. These results agree with previous reports. Point mutations were more frequent in adenomas than in carcinomas, with villous adenomas presenting a higher incidence of mutations than other adenomas. The association between clinical and histopathological parameters was investigated. Our study is the beginning of a new research line in molecular epidemiology of colorectal cancer and is the first to be carried out in one part of the Mexican population.

Background Chlamydia trachomatis is the causative agent of the most common bacterial sexually transmitted infection worldwide. The aim of this study was to investigate the frequency and genotypes of C. trachomatis in patients attending an obstetrics and gynecology clinic in Jalisco, Mexico and correlates them with sociodemographic, behavioral, and biological factors.Methods C. trachomatis detection was performed in endocervical samples from 662 patients by direct fluorescence assay (DFA) and two PCR assays that amplified the phospholipase D endonuclease superfamily protein (PLDESP) and OmpA genes. Positive samples were genotyped using PCR–restriction fragment length polymorphism assays. Sociodemographic, behavioral, and biological data were collected.ResultsThe mean age of the study population was 31 (range, 14–78) years. C. trachomatis positivity was detected by DFA in 16.7% (n = 111), PLDESP gene amplification in 14.2% (n = 94), and OmpA gene amplification in 14.5% (n = 96) of the population. Eight C. trachomatis genotypes were detected: E (39.6%), F (29.2%), D (15.6%), K (6.3%), L2 (3.1%), G, J, and I (2.1% each). C. trachomatis infection was associated with age, marital status, pregnancy, and hormonal contraceptive use (all p = 0.01); intrauterine device use and previous premature birth (both p = 0.03); and infection during pregnancy, previous ectopic pregnancy, pelvic inflammatory disease (PID), and green vaginal discharge (all p = 0.04). C. trachomatis genotype K was more likely to be detected in women histories of ≥2 sexual partners, genotype F was more likely in pregnant women, genotype L2 was more likely in women with PID, genotype D was more likely in women who had had infection during previous pregnancies, and genotype E was more likely in those with previous ectopic pregnancies and green vaginal discharge (all p = 0.01).ConclusionsThe frequency of C. trachomatis in our population was higher than previously reported worldwide, but within the range reported for Mexico. Genotype E was detected most frequently in the study population. Infection by C. trachomatis and C. trachomatis genotypes K, F, D, and E was strongly associated with multiple sociodemographic, behavioral, and biological factors. C. trachomatis genotype L2 was detected in women with PID.

Healthy adult cartilage is thought to have little or no capacity to renewal, and cell turnover has not been reported in lung cartilage. We report that chondrocyte turnover occurs in lung cartilage, found in an unrelated study. Lung specimens from CD1 mice of 2, 6, 12, 18 or 24 months were fixed in 10% neutral-buffered formalin and paraffin-embedded. Apoptosis was analysed by in situ end-labelling of fragmented DNA. Proliferating cell nuclear antigen (PCNA) and nestin were examined by immunohistochemistry. Apoptosis and PCNA were detected in lung chondrocytes. Serial section analysis showed that cells in apoptosis were different from PCNA-positive cells, indicating that turnover was occurring. Chondrocytes were negative for nestin. Nestin-positive cells were present in connective tissue associated with cartilage, in some specimens in close proximity of it and in perivascular cells. Thus cell turnover in lung cartilage is possible, which may be mediated by nestin-positive cells.

Dipterous fly larvae (maggots) are frequently collected from a corpse during a criminal investigation. Previous studies showed that DNA analysis of the gastrointestinal contents of maggots might be used to reveal the identity of a victim. However, this approach has not been used to date in legal investigations, and thus its practical usefulness is unknown. A badly burned body was discovered with its face and neck colonized by fly larvae. Given the condition of the body, identification was not possible. Short tandem repeat (STR) typing was performed using the gastrointestinal contents of maggots collected from the victim and was compared to STR profiles obtained from the alleged father. The probability of paternity was 99.685%. Thus, this comparative DNA test enabled the conclusive identification of the remains. This is the first reported case of analysis of human DNA isolated from the gastrointestinal tract of maggots used to identify a victim in a criminal case.

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Background and Aims: Environmental and genetic factors play a role in the pathogenesis and natural history of non-alcoholic steatohepatitis (NASH). The aim of this study was to determine if the G-238A (allele TNFA) and G-308A (allele TNF2) tumor necrosis factor-alpha (TNF-) and Ala9Val manganese superoxide dismutase (MnSOD) polymorphisms were associated with NASH in a case-control study of subjects from Northeast Mexico. Methods: We analyzed DNA samples from 68 patients with NASH (50 women and 18 men; mean age ± SD, 33.9 ± 10.8 years; BMI 43.9 ± 7.2 kg/m 2 ) and 100 healthy subjects (44 women and 56 men; mean age ± SD, 27.8 ± 10.8 years; BMI 23 ± 1.6 kg/m 2 ). The diagnosis was based on liver biopsy reviewed by two pathologists blinded to clinical data. The polymorphisms were evaluated using the polymerase chain reaction-restriction fragment length polymorphism method. Results: The frequency of G-238A TNF-and Ala9Val MnSOD polymorphisms in NASH patients was significantly higher in comparison with control subjects (OR = 3.06, 95% CI 1.29-7.33, p = 0.0047 and OR = 6.28, 95% CI 2.95-13.55, p = 0.001, respectively). In contrast, the G-308A TNF-polymorphism did not show a statistical difference between either group (OR = 1.04, 95% CI 0.45-2.38, p = NS). Analyzed populations were in Hardy-Weinberg equilibrium. Conclusions: Our results suggest that G-238A TNF-and Ala9Val MnSOD polymorphisms, which are molecules involved in inflammation and cellular oxidative stress, could be associated with NASH. These data may contribute to understanding the genetic susceptibility to NASH.

Peroxisomicine A1 (PA1) is a potential antineoplastic agent with high and selective toxicity toward peroxisomes of tumor cells. Pexophagy is a selective autophagy process that degrades damaged peroxisomes; this process has been studied mainly in methylotrophic yeasts. There are two main modes of pexophagy in yeast: macropexophagy and micropexophagy. Previous studies showed that peroxisomes damaged by a prolonged exposition to PA1 are eliminated by macropexophagy. In this work, Candida boidinii was grown in methanol‐containing media, and PA1 was added to the cultures at 2 µg/mL after they reached the mid‐exponential growth phase. Samples were taken at 5, 10, 15, 20, and 25 min after the addition of PA1 and processed for ultrastructural analysis. Typical morphological characteristics of micropexophagy were observed: the direct engulfment of peroxisomes by the vacuolar membrane and the presence of the micropexophagic membrane apparatus (MIPA), which mediates the fusion between the opposing tips of the vacuole to complete sequestration of peroxisomes from the cytosol. In conclusion, here we report that, in addition to macropexophagy, peroxisomes damaged by PA1 can be eliminated by micropexophagy. This information is useful to deepen the knowledge of the mechanism of action of PA1 and of that of pexophagy per se.