Alberto Niderhauser-García

Frequency and Clinicopathology Associations of K-ras Mutations in Colorectal Cancer in a Northeast Mexican Population

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.

Evidence of chondrocyte turnover in lung cartilage, with the probable participation of nestin-positive cells.

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.

Phagocytosis of spermatozoa and leucocytes by epithelial cells of the genital tract in infertile men infected with Chlamydia trachomatis and mycoplasmas

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Multinucleation of spermatozoa and spermatids in infertile men chronically exposed to carbofuran

OBJECTIVEnTo report the findings encountered in semen samples coming from two infertile men chronically exposed to carbofuran.nnnMETHODSnSemen samples were collected and analyzed as recommended by the World Health Organization. A morphological analysis was carried out by light microscopy.nnnRESULTSnSeminal analysis revealed in the first case a total concentration of 42 million spermatozoa/mL with 17% motility and 20% normal shape. The second patient presented a total concentration of 5 million spermatozoa/mL with 6% motility and 2% normal shape. The patients presented a similar percentage of binucleated spermatozoa (28 and 26%) and of multinucleated spermatids (10 and 6%).nnnCONCLUSIONnTo our knowledge, this is the first time that alterations in semen samples of men exposed to carbofuran are reported. More research in this area is needed to make conclusions on the subject.

The Role of Chlamydia trachomatis in Male Infertility

Chlamydia spp. are associated with a broad clinical spectrum of human diseases, including cardiovascular disease, and pulmonary, ocular and urogenital tract infections [1]. C. trachomatis is an obligate intracellular pathogen. The infection cycle starts with the entry of an infectious particle (elementary body or EB) into an epithelial cell. The EB-laden cytoplasmic vacuole (inclusion) migrates to the peri-Golgi region as the EB differentiates into a noninfectious but metabolically active reticulate body (RB). After replication, progeny RBs differentiate back to EBs for exiting the infected cells to disseminate to adjacent cells [2].

Frequency and genotypes of Chlamydia trachomati s in patients attending the obstetrics and gynecology clinics in Jalisco, Mexico and correlation with sociodemographic, behavioral, and biological factors

BackgroundChlamydia 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.MethodsC. 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% (nxa0=xa0111), PLDESP gene amplification in 14.2% (nxa0=xa094), and OmpA gene amplification in 14.5% (nxa0=xa096) 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 pxa0=xa00.01); intrauterine device use and previous premature birth (both pxa0=xa00.03); and infection during pregnancy, previous ectopic pregnancy, pelvic inflammatory disease (PID), and green vaginal discharge (all pxa0=xa00.04). 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 pxa0=xa00.01).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.