Prevalence of human papillomavirus types in North and Central regions of Mexico.

Human papillomavirus (HPV) is a DNA virus linked to mucosal and cutaneous carcinogenesis. More than 200 different HPV types exist. We carried out a transversal study to investigate the prevalence of HPV types in two regions of Mexico. A total of 724 genital and non-genital samples from women (F) and men (M) were studied; 241 (33%) from North-Eastern (NE) and 483 (66%) from South-Central (SC) Mexico. The overall prevalence was 87%. In genital lesions from females, the NE group showed a prevalence of HPV types 16 (37%), 6 (13%), 59 (6%), 11, 18 and 66 (5.4% each); and the SC group showed types 6 (17%), 16 (15%), 11 (14.5%), 18 (12%) and 53 (6%). In the genital lesions from males, NE group showed types 16 (38%), 6 (21%), 11 (13%) and 59 plus 31 (7.5%) and the SC group showed types 6 (25%), 11 (22%), 18 (17%) and 16 (11.5%). When the two regions were compared, a higher prevalence of low-risk HPV 6 and 11 was found in the SC region and of high-risk HPV 59, 31 and 66 (the latter can also be present in benign lesions) in the NE region. Our findings complement efforts to understand HPV demographics as a prerequisite to guide and assess the impact of preventive interventions.

Polymorphisms in GSTM1, GSTT1, GSTP1, and GSTM3 genes and breast cancer risk in northeastern Mexico.

Glutathione S-transferases (GSTs) are a family of phase II metabolizing enzymes involved in carcinogen detoxification and the metabolism of various bioactive compounds. Several genes that code for these enzymes are polymorphic in an ethnicity-dependent manner, with particular genotypes previously associated with an increased risk of breast cancer. The purpose of this study was to determine the frequencies of polymorphisms in the genes GSTM1, GSTT1, GSTP1, and GSTM3 and to investigate whether an association exists between these genes and breast cancer risk in subjects from northeastern Mexico. Genotypes were determined for 243 women with histologically confirmed breast cancer and 118 control subjects. Gene polymorphisms were analyzed using a DNA microarray. We found an increased breast cancer risk associated with the GSTM1 gene deletion polymorphism (OR = 2.19; 95%CI = 1.50-3.21; P = 0.001). No associations between the GSTT1, GSTP1, and GSTM3 genotypes and neoplasia risk were observed. In conclusion, we determined the genotype distribution of GST polymorphisms in control subjects and breast cancer patients from northeastern Mexico. The GSTM1 null genotype was associated with breast cancer risk. Our findings may be used to individualize breast cancer screening and therapeutic intervention in our population, which displays ethnic characteristics that differentiate it from other populations in Mexico.

Intraprostatic distribution and long-term follow-up after AdV-tk immunotherapy as neoadjuvant to surgery in patients with prostate cancer.

A phase I-II study to evaluate gene-mediated cytotoxic immunotherapy in newly diagnosed prostate cancer before radical prostatectomy was conducted in Monterrey, Mexico. First, to investigate delivery of adenovirus to the prostate, fluorescently labeled vector was injected into fresh prostatectomy specimens and distribution was visually analyzed. The optimal volume and site instillation was then used for transrectal ultrasound guided intraprostatic injection in 10 patients with adenocarcinoma scheduled for radical prostatectomy. Each received two apical and two basal 0.5 ml injections of AdV-tk for a total of 1 × 10(11) vp followed by 14 days of prodrug. Nine patients continued to tumor resection: six high risk, one intermediate and two low risk. In vivo vector distribution was analyzed from the resected tissue of four patients. Patients were monitored for tumor progression and acute and long-term safety. For vector delivery, two apical and two basal injections of 0.5 ml led to optimal organ-wide distribution ex vivo and in vivo. Cytotoxicity was evidenced by transient rise in PSA and tumor histology. There were no significant adverse events deemed related to the treatment and no late toxicities after median follow-up of 11.3 years. All six high-risk patients had positive surgical margins and one had seminal vesicle involvement. Despite slow PSA rise post surgery in three of these patients, none developed metastases. The intermediate- and low-risk patients had complete resections and none have progressed. In conclusion, in vivo transrectal ultrasound guided instillation of an adenoviral vector into four sites in the prostate was practical as an outpatient procedure, well tolerated and led to distribution throughout the intraprostatic tumor mass. AdV-tk demonstrated no significant acute or late toxicities. Trends in PSA and disease progression conveyed the possibility of a sustained immune response against residual disease.

Olfactomedin-like 3 (OLFML3) gene expression in baboon and human ocular tissues: cornea, lens, uvea, and retina.

BACKGROUND: Olfactomedin-like is a family of polyfunctional polymeric glycoproteins. This family has at least four members. One member of this family is OLFML3, which is preferentially expressed in placenta but is also detected in other adult tissues including the liver and heart. However, its orthologous rat gene is expressed in the iris, sclera, trabecular meshwork, retina, and optic nerve. METHODS: OLFML3 messenger amplification was performed by RT-PCR from human and baboon ocular tissues. The products were cloned and sequenced. RESULTS: We report OLFML3 expression in human and baboon eye. The full coding DNA sequence has 1221 bp, from which an open reading frame of 406 amino acid was obtained. The baboon OLFML3 gene nucleotidic sequence has 98% and amino acidic 99% similarity with humans. CONCLUSIONS: OLFML3 gene expression in human and baboon ocular tissues and its high similarity make the baboon a powerful model to deduce the physiological and/or metabolic function of this protein in the eye.

Biodegradation kinetics of BTE-OX and MTBE by a diesel-grown biomass.

The biodegradation kinetics of BTE-oX and MTBE, mixed all together in the presence of diesel-grown bioaugmented bacterial populations as high as 885 mg/L VSS, was evaluated. The effect of soil in aqueous samples and the effect of Tergitol NP-10 on substrate biodegradation rates were also evaluated. Biodegradation kinetics was evaluated for 54 h, every 6 h. All BTE-oX chemicals followed a first-order two-phase biodegradation kinetic model, whereas MTBE followed a zero-order removal kinetic model in all samples. BTE-oX removal rates were much higher than those of MTBE in all samples. The presence of soil in aqueous samples retarded BTE-oX and MTBE removal rates. The addition of Tergitol NP-10 to aqueous samples containing soil had a positive effect on substrate removal rate in all samples. Substrate percent removals ranged between 64.8-98.9% for benzene, toluene and ethylbenzene. O-xylene and MTBE percent removals ranged between 18.7-40.8% and 7.2-10.3%, respectively.

BTE-OX biodegradation kinetics with MTBE through bioaugmentation.

The biodegradation kinetics of BTE-oX and MTBE, mixed all together, in the presence of bioaugmented bacterial populations as high as 880 mg/L VSS was evaluated. The effect of soil in aqueous samples and the effect of Tergitol NP-10 on substrate biodegradation rates were also evaluated. Biodegradation kinetics was evaluated for 36 hours, every 6 hours. Benzene and o-xylene biodegradation followed a first-order one-phase kinetic model, whereas toluene and ethylbenzene biodegradation was well described by a first-order two-phase kinetic model in all samples. MTBE followed a zero-order removal kinetic model in all samples. The presence of soil in aqueous samples retarded BTE-oX removal rates, with the highest negative effect on o-xylene. The presence of soil enhanced MTBE removal rate. The addition of Tergitol NP-10 to aqueous samples containing soil had a positive effect on substrate removal rate in all samples. Substrate percent removals ranged from 95.4-99.7% for benzene, toluene and ethylbenzene. O-xylene and MTBE percent removals ranged from 55.9-90.1% and 15.6-30.1%, respectively.

Molecular cloning, sequencing and characterization of omp48, the gene encoding for an antigenic outer membrane protein from Aeromonas veronii.

AIMS: To clone, sequence and characterize the gene encoding the Omp48, a major outer membrane protein from Aeromonas veronii. METHODS AND RESULTS: A genomic library of Aer. veronii was constructed and screened to detect omp48 gene sequences, but no positive clones were identified, even under low stringency conditions. The cloned gene probably was toxic to the host Escherichia coli strain, so the cloning of omp48 was achieved by inverse PCR. The nucleotide sequence of omp48 consisted of an open reading frame of 1278 base pairs. The predicted primary protein is composed of 426 amino acids, with a 25-amino-acid signal peptide and common Ala-X-Ala cleavage site. The mature protein is composed of 401 amino acids with a molecular mass of 44,256 Da. CONCLUSIONS: The omp48 gene from Aer. veronii was cloned, sequenced and characterized in detail. BLAST analysis of Omp48 protein showed sequence similarity (over 50%) to the LamB porin family from other pathogenic Gram-negative bacteria. SIGNIFICANCE AND IMPACT OF THE STUDY: Bacterial diseases are a major economic problem for the fish farming industry. Outer membrane proteins are potentially important vaccine components. The characterization of omp48 gene will allow further investigation of the potential of Omp48 as recombinant or DNA vaccine component to prevent Aer. veronii and related species infections in reared fish.

[677T mutation of the MTHFR gene in adenomas and colorectal cancer in a population sample from the Northeastern Mexico. Preliminary results]. / Mutación 677T del gen MTHFR en adenomas y cáncer colorrectal en una muestra de la población del noreste de México. Resultados preliminares.

INTRODUCTION: Adequate intake of folates has been associated to low prevalence of colon cancer. Methylenetetrahydrofolate reductase enzyme (MTHFR) plays an important role in folate metabolism. The role of the 677 mutation at the MTHFR gene in the risk for colorectal cancer remains controversial. A recent report established that this mutation has a high prevalence in the healthy Mexican population. AIMS: To analyze the prevalence of 677T MTHFR mutation in patients with colorectal cancer and controls without chronic gastrointestinal disorders. METHODS: Seventy-four colorectal cancer, 32 adenomas and 110 normal samples were analyzed. Patients and controls were matched for sex and age. For each sample, DNA isolation, PCR, and mutation detection by restriction enzyme digestion were performed to determine the allele at the 677 position in the MTHFR gene. RESULTS: Genotype 677C/677C was found in 18.7, 20.3, and 30.9% in adenomas, cancer lesions and controls, respectively. Frequencies of the 677C/677T genotype were 59.4, 56.7, and 47.3%, in adenomas, cancer lesions, and controls, respectively. Genotype 677T/677T was found in 21.9, 23.0, and 21.8% in adenomas, cancer lesions, and controls, respectively. The odds ratio between genotypes carrying the mutation (T/T and C/T) and normal genotype (CC) was 1.81 (IC 95% 0.97-3.3), chi 2 = 3.5, p = 0.06. CONCLUSION: Our results showed that persons who carry the 677T mutation at MTHFR locus have a tendency for an increased risk for colorectal cancer. This study supports the basic concept that low levels of folic acid contribute with the colorectal cancer pathogenesis. Our lack of statistic significance may be due to reduced sample size.

Folate levels and N(5),N(10)-methylenetetrahydrofolate reductase genotype (MTHFR) in mothers of offspring with neural tube defects: a case-control study.

BACKGROUND: Neural tube defects (NTDs) have been associated with biochemical factors involved in the conversion of homocysteine to methionine as folate deficiency and the mutation 677T in the N(5),N(10)-methylenetetrahydrofolate reductase gene (MTHFR). METHODS: A case-control study was performed to detect this mutation in 38 unrelated women with NTD deceased products and 31 mothers without antecedents of NTD offspring. All products were born in Nuevo León (northeastern Mexico) during 1997. Erythrocyte and plasmatic folate levels and the genotype of the 677 polymorphism at the MTHFR locus were analyzed in both groups. RESULTS: Although no significant differences were found in mean blood folate levels, the percentage of women in the case group with erythrocyte folate levels <160 ng/mL was significantly higher than in the control group (75 vs. 51.2%, p <0.05). The proportion of women with plasma folate levels <3.5 ng/mL was higher in the case group (16.2 vs. 0%, p <0.01). Genotype analysis demonstrated a significantly higher proportion of 677T homozygous mothers with NTD products (39.6 vs. 9.1%, p <0.05). Allele frequencies for the 677T mutation were 0.55 and 0.36 for cases and controls, respectively. The odds ratio (OR) for having a NTD product was 6.1 (95%, CI 1.56-23.6) for homozygous 677T mothers vs. homozygous 677C and heterozygous mothers. Significantly low levels of erythrocyte folate were found in the 677C homozygous case group and in plasma folate in the 677C/677T heterozygous case mothers. CONCLUSIONS: Our study suggests that folate deficiency and MTHFR unfavorable genotype in mothers are important risk factors for severe NTD phenotype in our population.

[Breast cancer genetics. BRCA1 and BRCA2: the main genes for disease predisposition]. / Genética del cáncer de mama. BRCA1 y BRCA2: los principales genes de predisposición a la enfermedad.

Breast cancer is among the most common world cancers. In Mexico this neoplasm has been progressively increasing since 1990 and is expected to continue. The risk factors for this disease are age, some reproductive factors, ionizing radiation, contraceptives, obesity and high fat diets, among other factors. The main risk factor for BC is a positive family history. Several families, in which clustering but no mendelian inheritance exists, the BC is due probably to mutations in low penetrance genes and/or environmental factors. In families with autosomal dominant trait, the BRCA1 and BRCA2 genes are frequently mutated. These genes are the two main BC susceptibility genes. BRCA1 predispose to BC and ovarian cancer, while BRCA2 mutations predispose to BC in men and women. Both are long genes, tumor suppressors, functioning in a cell cycle dependent manner, and it is believed that both switch on the transcription of several genes, and participate in DNA repair. The mutations profile of these genes is known in developed countries, while in Latin America their search has just began. A multidisciplinary group most be responsible of the clinical management of patients with mutations in BRCA1 and BRCA2, and the risk assignment and Genetic counseling most be done carefully.

[Genetic aspects of asthma]. / Aspectos genéticos del asma.

Asthma is a complex disease associated with bronchial hyperreactivity and atopy, making asthma a disease with a phenotype that has been clinically difficult to define. Despite intense research, prevalence of asthma remain relatively high. The key reason for the high prevalence and morbility is that the fundamental mechanisms predisposing individuals to the development of asthma are not understood. Familial aggregation observed in this pathology has prompted for the search of an involved genetic component. This task is difficult due to the complex nature of asthma. A universally accepted definition for this disease is not available, clinical expression can be modulated by environmental factors, and inheritance does not follow a clear Mendelian pattern. Establishment of more precise clinical and laboratory criteria has improved the design and interpretation of genetic studies. Twin analysis and segregation studies have demonstrated an important genetic component with a probably multifactorial pattern of inheritance. "Sib pair" studies and familial segregation analyses have shown linkage between some chromosomal regions and asthma, including chromosome 5, 6, 7, 11 and 14. The search for major genes in these chromosomal segments has been focused on loci involved in the allergic process. Among these, the loci for IL-9 and IL-13 in chromosome 5 seem to play an important role in the pathogenesis of asthma. Understanding the fundamental gene-environmental interactions in the development of asthma should lead to earlier identification of susceptible individuals and more effective approaches for disease prevention.

Risk factors of breast cancer in Mexican women.

OBJECTIVE: To investigate the association between family history (FH) of neoplasia, gyneco-obstetric factors and breast cancer (BC) in a case-control study. In cases, to analyze those variables in relation with early onset of BC, the manner of detection (self-examination, prompted by pain, or casual), the size of tumor, and the elapsed time to seek medical attention. MATERIAL AND METHODS: Data from 151 prevalent BC cases and 235 age-matched controls were analyzed by multiple logistic regression, to assess the influence of BC risk factors. RESULTS: Ten per cent of patients and 1% of controls had first-degree relatives (FDR) with BC. Family history of FDR with BC (OR, 11.2; 95% CI 2.42-51.92) or with gastric or pancreatic cancer (OR, 17.7; 95% CI 2.2-142.6) was associated with BC risk. Breastfeeding at or under 25 years of age was protective against BC (OR, 0.40; 95% CI 0.24-0.66). The manner of tumor detection did not influence its size at the time of diagnosis. CONCLUSIONS: Our study confirms that FH of BC and/or of gastric or pancreatic carcinoma are risk factors for BC, while lactation at 25 years of age or earlier is protective.

CFTR mutations in three Latin American countries.

We analyzed 192 cystic fibrosis (CF) alleles in three Latin American countries: Mexico, Colombia, and Venezuela. Mutation screening was performed by polymerase chain reaction (PCR) and a reverse dot blot detection kit that enables determination of 16 of the most common CF mutations worldwide. Mutations were detected in 47.9% of the screened CF alleles. The most prevalent CF allele was DeltaF508 (39. 6%). The remaining 16 non-DeltaF508 detectable mutations represented 8.3% of the CF alleles. Among them, the G542X, N1303K, and 3849+10kb C>T were the most common. Although the frequency of DeltaF508 described here is lower than that reported for Caucasian populations, including in Spain, it is remarkable that mutation prevalences found in this study resemble those observed in Spain. Two of these mutations, G542X and 3849+10kb C>T, that were relevant in this analysis, have a particularly high incidence in Spanish communities. The low frequency of DeltaF508 described here may be explained by the Amerindian, Caucasian, and Black admixture that occurred in Latin America after the discovery of the New World, and also by the probable occurrence of mutations contributed by the original natives, which were undetectable in this analysis.

Functional domains of human growth hormone necessary for the adipogenic activity of hGH/hPL chimeric molecules.

Genetic analysis through construction of chimeric genes and their transfection in mammalian cells could provide a better understanding of biological functions of native or modified proteins, and would allow the design of new gene constructs encoding peptides that mimic or block ligand interaction with target tissues. To identify the hGH domains responsible for induction of adipose differentiation we constructed hGH/hPL chimeric molecules using homologous DNA mutagenesis, since hGH, but not human placental lactogen (hPL), promotes adipose differentiation in mouse 3T3-F442A cells. We assayed their adipogenic activity in an autocrine/paracrine biological model consisting of transiently transfected 3T3-F442A cells with the chimeric constructs. Plasmid DNAs carrying these constructs were transfected into growing 3T3-F442A cells, and cultures were further maintained for 7 days to differentiate into adipocytes. Secretion of transfected hGH/hPL chimeric proteins into the medium was in the range of 5-25 ng/ml. Adipogenic activity was a property only of those chimeric proteins that contained hGH exon III together with either hGH exon II or hGH IV. Our results also suggest that hGH binding site-2 is composed of two structural subdomains: subsite 2A encoded by exon II of hGH and subsite-2B encoded by exon IV. We also suggest that full adipogenic activity requires the presence of binding site-1 and any of the subsites of binding site-2. This simple autocrine/paracrine biological model of gene transfection allows the analysis of specific biological activity of products encoded by modified genes.

[Genetic transcription in eukaryotes: from transcriptional factors to disease]. / Transcripción génica en eucariotes: de los factores transcripcionales a la enfermedad.

The organisms' genetic information is stored as DNA sequences: the genes. The most important level of gene expression regulation is exerted at the transfer process of this information from the genes into messenger RNA molecules; this process is called transcription and is carried out by a molecular machinery conformed by hundreds of different proteins which are assembled in an ordered step way. These proteins or transcriptional factors are classified according to their mode of action in 4 groups: general transcriptional factors, activators, coactivators and repressors. There are diseases like. Aniridia, the Rubinstein-Taybi syndrome and Hodgkin's disease, in which some transcriptional factor have been involved and in some, the molecular cause i.e. the mutations responsible for the molecular dysfunction in a transcriptional factor has been elucidated. Understanding at the molecular level the transcription process will help to comprehend the relationship of it with the development and health of the organism.

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.

Detecting residual bcr-abl transcripts in chronic myeloid leukaemia patients using coupled reverse transcriptase-polymerase chain reaction with rTth DNA polymerase.

The bcr-abl fusion gene is the hallmark of chronic myeloid leukaemia (CML) and presumably the cause of its development. Accordingly, long-term disappearance of the bcr-abl gene after intensive therapy suggests that a patient is probably cured of CML. The diagnostic protocol based on coupling of two enzymatic reactions, reverse transcription (RT) and nested polymerase chain reaction (nPCR), for the detection of bcr-abl transcripts in peripheral blood provides a powerful tool for minimal residual CML detection. We have developed a new detection protocol using rTth DNA polymerase as the only enzyme catalysing both reactions for simplifying CML diagnosis. We demonstrate its efficacy investigating residual leukaemic cells in the peripheral blood of 10 patients. This assay offers several advantages over the use of conventional RT-PCR, being more sensitive, faster, less prone to false positives since no opening of the tube is required between the two reactions and requires no special oils or waxes. Our simple assay for bcr-abl chimeric transcripts detection is a practical addition to the diagnostic evaluation of the patient with chronic myeloid leukaemia.

Growth hormone and placental lactogen: biology, medicine and biotechnology.

Molecular cloning gave us access to the gene members of the human growth hormone and placental lactogen multigene family. Genomic sequencing provided clues for the understanding of the origin, functioning and regulation of this family. It has also allowed us to develop new diagnostic approaches for deficiencies of these hormones and to make new biotechnological contributions.

Absence of human placental lactogen and placental growth hormone (HGH-V) during pregnancy: PCR analysis of the deletion.

Human placental lactogen (HPL) is produced in large amounts in normal pregnancies. We report a pregnancy with complete lack of HPL and the placental variant of the human growth hormone HGH-V. The pregnancy resulted in a severely growth-retarded but otherwise normal male baby. PCR analysis of DNA extracted from the placenta showed that the HPL encoding genes hPL-4 and hPL-3 were deleted along with the human growth hormone variant gene (hGH-V), which is located between these two active hPL genes and also expressed in the normal placenta. Of the five members of this multigene family, hGH-N, which is expressed in the pituitary gland, and hPL-1, a presumed pseudogene, were left intact. The latter (hPL-1) was expressed as RNA transcripts only at very low levels as is usually reported in normal pregnancies. Analysis of the parents' DNA showed that both of them carried a different heterozygous deletion at the 3' end of the hGH/hPL locus.