Search

Before the arrival of the Spanish conquerors, Mitla was the second most important city in the valleys of Oaxaca, México. However, the ruins that are visible today do not seem to match the size of a city of more than 10,000 inhabitants. Geological and geophysical studies suggest that part of the city was covered by the deposits of a dry landslide likely to have been caused by an earthquake with a magnitude that could vary between 6 and 7. This landslide is monolithological, which is why two geophysical methods were used in order to evaluate its geometrical characteristics and to suggest the possible existence of archeological remains under the landslide. [ABSTRACT FROM AUTHOR]

Trials were planted at Rio Bravo, Tamaulipas, Mexico, during 2002 and 2003 with the objective of determining the relationship between sorghum ergot severity and weather factors, and to develop a risk assessment model. Six sorghum hybrids and three male-sterile genotypes were planted every month from January to October. At anthesis initiation, inoculation was conducted using a local isolate of Claviceps africana. Among hybrids, there was a negative relationship between ergot severity and maximum and minimum temperatures, with the highest significant correlation of –0.71 from 7 to 9 days before anthesis. During this period, minimum temperatures above 10°C increased the risk of ergot development, whereas minimum temperatures above 22.5°C prevented ergot development. In male-sterile plants, ergot was negatively related to maximum temperature after anthesis, with ergot being observed at maximum temperatures up to 38°C. Minimum relative humidity showed a positive and significant correlation with ergot severity. Values of minimum relative humidity above 30% during anthesis promoted infection. Surface response regression models were developed for the effects of minimum relative humidity and minimum and maximum temperature during the infection process on ergot severity. [ABSTRACT FROM AUTHOR]

Ceramic samples found in San Miguel Ixtapan, Mexico State, Mexico, were analyzed by means of NAA, PIXE, SEM and XRD. Statistical treatments such as bivariate cluster and principal-components analysis were applied to the data set. The origins of these ceramic samples were classified as local, regional and foreign. [ABSTRACT FROM AUTHOR]

Introduction and Aims: Posttransplantation diabetes mellitus (PTDM) is a serious long-term complication that has a negative impact on graft and patient survival. The purpose of the present study was to describe the incidence of PTDM in a Mexican cohort and evaluate its association with a previous family history of diabetes (FHD)., Methods: A retrospective single-center cohort study was conducted on patients undergoing liver transplantation (LT). The primary outcome was time from LT to PTDM. The diagnosis of PTDM was established using the ADA criteria. A mediation analysis that used adjusted Cox regression models and considered pretransplant prediabetes a mediator was performed, to determine the total effect and direct effect of FHD on PTDM., Results: A total of 152 patients were included, with a median follow-up time of 41 months; 19.2% (n = 29) had pretransplant diabetes. During the follow-up time, 15% of patients developed PTDM (n = 23), with an incidence rate of 4.71 cases/100 person-years. PTDM was significantly higher in patients with FHD, compared with those with no FHD (8.72 cases/100 person-years vs 2.04 cases/100 person-years, respectively; p = 0.001). The adjusted hazard ratio of PTDM for FHD was 4.14 (95% CI 1.60-10.7), p = 0.005) and 3.48 (95% CI 1.35-9.01, p = 0.010), when further controlled for pretransplant prediabetes., Conclusion: The occurrence of PTDM was similar to that reported in most international studies. As with type 2 diabetes, family history plays an important role in the development of PTDM, even after accounting for pretransplant prediabetes. Patients with FHD should undergo a stricter metabolic program., (Copyright © 2023 Asociación Mexicana de Gastroenterología. Published by Masson Doyma México S.A. All rights reserved.)

The objective of this study was to describe the epidemiology of Toxoplasma gondii and Neospora caninum infection by estimating seroprevalence and its association with certain risk factors in goats from Aguascalientes, Mexico. A total of 150 blood samples was taken from 10 farms and serum samples were subjected to enzyme-linked immunosorbent assay indirect test to detect T. gondii and N. caninum antibodies; the association between seroprevalence and some potential risk factors was estimated through logistic regression analysis. The general seroprevalence for T. gondii was 12.6%, observed in the farms in a range of 6.6 to 60%, finding seropositive animals in 80% of them; for N. caninum the seroprevalence was 3.3% and in farms a range of 6.6 to 13.3% was identified and 30% of them had at least 1 seropositive animal. The coinfection was 0.66%. The risk analysis for T. gondii identified a history of abortions (odds ratio 9.25) as a factor associated with seroprevalence; for N. caninum, no risk factor was identified., (© American Society of Parasitologists 2023.)

Introduction: During the height of the coronavirus disease-19 (COVID-19) pandemic, some renal replacement therapy (RRT) modalities were insufficient, forcing medical centers to diversify the RRT modalities offered. In this study, we reported the outcomes of chronic peritoneal dialysis (PD) patients and acute PD in critically ill patients during COVID-19 pandemic in a tertiary care medical center in Mexico., Methods: This descriptive, longitudinal, observational, retrospective study included 47 adult patients with atypical pneumonia in a tertiary care medical center in Mexico during the first and second waves of the COVID-19 pandemic. Chronic PD patients and PD incident patients due to acute kidney injury (AKI) were included., Results: Forty-seven patients were studied (29 chronic PD patients and 18 incident PD patients due to AKI); median age was 59 (48-68) years; 63.8% were men. The ultrafiltrate volume per day was 815 (596.1-1,193.2) mL. Overall mortality was 61.7%, 55.2% in chronic PD patients, and 72.2% in PD incident patients due to AKI. A higher Sequential Organ Failure Assessment (SOFA) score, the need for mechanical ventilation at admission, and the requirement for vasopressors were predictors for mortality (p < 0.01)., Conclusion: In low- and lower-middle-income countries, PD was a valid alternative for RRT during the COVID-19 pandemic. In AKI patients, PD can correct hyperkalemia, acidosis, uremia, and volume overload; however, there was higher mortality in PD incident patients due to AKI. The main risk factors for mortality were a high SOFA score at admission, the need for invasive mechanical ventilation, and the requirement for vasopressors., (© 2023 S. Karger AG, Basel.)

Background: Research using the IPSCAN Child Abuse Screening Tool for Children (ICAST-C), has provided ample evidence of the magnitude of violence against children. Knowledge about its psychometric characteristics and validity is limited. Hence, our objective was to translate and culturally adapt the ICAST-C in adolescents from Mexico City and determine its psychometric properties., Participants and Setting: To determine the psychometric properties of the instrument 723 adolescents between 11 and 18 years of age from 9 public secondary schools in Mexico City participated., Methods: The study was carried out in two phases: 1) translation and adaptation of the instrument (in 5 steps) and 2) pilot evaluation of the psychometric properties. Total and factor reliabilities were determined, Pearson correlation was used for temporal stability while construct validity was determined by Confirmatory Factor Analysis (CFA), and final adequacy of the items eliminated by the CFA., Results: We developed the culturally relevant Mexican Spanish version of the ICAST-C. The CFA confirmed the six-factor structure hypothesis. To improve the original model we eliminated ten items, the final model showed good global fit indices (χ2(1310) = 2207.68, p < .01, χ2/df = 1.68; CFI =0.95; RMSEA = 0.02 [CI95% 0.02-0.03]; SRMR = 0.08). Total and factor reliabilities were adequate (Alpha = 0.79-0.92, r = 0.52-0.75), except for the non-violent discipline factor (Alpha = 0.59, r = 0.38)., Conclusions: While these data suggest that this version of the ICAST-C is valid and reliable for adolescents in Mexico City public secondary schools, further research should evaluate the psychometric properties in a national sample., Competing Interests: Declaration of competing interest None., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Spinocerebellar ataxias (SCAs) conform a heterogeneous group of neurodegenerative disorders with autosomal dominant inheritance. Five of the most frequent SCAs are caused by a CAG repeat expansion in the exons of specific genes. The SCAs incidence and the distribution of polymorphic CAG alleles vary among populations and ethnicities. Thus, characterization of the genetic architecture of ethnically diverse populations, which have undergone recent admixture and demographic events, could facilitate the identification of genetic risk factors. Owing to the great ethnic diversity of the Mexican population, this study aimed to analyze the allele frequencies of five SCA microsatellite loci (SCA1, SCA2, SCA3, SCA6, and SCA7) in eleven Mexican Native American (MNA) populations. Data from the literature were used to compare the allelic distribution of SCA loci with worldwide populations. The SCA loci allelic frequencies evidenced a certain genetic homogeneity in the MNA populations, except for Mayans, who exhibited distinctive genetic profiles. Neither pathological nor large normal alleles were found in MNA populations, except for the SCA2 pre-mutated allele in the Zapotec population. Collectively, our findings demonstrated the contribution of the MNA ancestry in shaping the genetic structure of contemporary Mexican Mestizo populations. Our results also suggest that Native American ancestry has no impact on the origin of SCAs in the Mexican population. Instead, the acquisition of pathological SCA alleles could be associated with European migration.

Background: SARS-COV2 appears less frequently and less severely in the pediatric population than in the older age groups. There is a need to precisely estimate the specific risks for each age group to design health and education policies suitable for each population. Objective: This study aimed to describe the risk of death in SARS-COV2 infected subjects by age group and according to the presence of comorbidities. Methods: We analyzed data of confirmed SARS-COV2 infection cases where symptoms began between February 22th, 2020, and April 18th, 2021, as published by the General Epidemiology Direction (DGE) of the Mexican Ministry of Health. We calculated COVID-19 incidence and mortality by age group using population data from the Statistics and Population National Institute (INEGI), and estimated the association between risk of death and the presence of comorbidities. Results: Mortality in SARS-COV2 infected people varied considerably, between 7 and 155 deaths per million per year in the under-20 age groups compared to 441 to 15,929 in the older age groups. Mortality in pediatric populations is strongly associated with comorbidities (OR: 4.6-47.9) compared to the milder association for older age groups (OR: 3.16-1.23). Conclusion: The risk of death from SARS-COV2 infection in children is low and is strongly associated with comorbidities., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 González-García, Castilla-Peón, Solórzano Santos, Jiménez-Juárez, Martínez Bustamante, Minero Hibert and Garduño-Espinosa.)

Three new species of the genus Longior Travassos Kloss, 1958 are described and illustrated, namely L. surieli n. sp. in Antillanax dominicanus (Doesburg, 1953) from the Dominican Republic, L. lamothei n. sp. in Passalus punctiger Le Peletier Serville, 1825 from Mexico and Colombia and L. zumpimito n. sp. in P. punctatostriatus Percheron, 1835 from Mexico. These constitute the first records of the genus Longior for the aforementioned countries, rising to nine species in the genus. The new species can be differentiated mainly by the length of their body, oesophagus and tail in both sexes, the extension of the lateral alae in the females and the morphology of the cephalic and posterior end in the males. The molecular phylogeny of the new taxa is inferred by the 28S and 18S rDNA and they form a monophyletic clade with other Longior species. The phylogeny of Longior and that of their passalid hosts reveal coevolutionary relationships. These patterns suggest that the phylogeny of Longior species is probably strongly influenced by the evolutionary trajectories of their passalid hosts.

Aims: Fragile-X syndrome (FXS) is the most common inherited form of intellectual disability; it is caused by an abnormal CGG-repeat expansion at the FMR1 gene. However, a few cases of girls with mutations in the FMR1 gene have been reported in the literature. In this study, we describe the clinical and genetic assessment of a family who exhibits the unusual coexistence of FXS, an 8p23.1 deletion, and balanced translocation t(7;10)(p10;q24) in multiple members, including a symptomatic girl with FXS. Materials and Methods: All of the family members underwent comprehensive clinical and neurological examinations. All members of the family were also molecularly diagnosed using a combination of fluorescent-polymerase chain reaction (PCR), Triplet Repeat Primed-PCR, capillary electrophoresis, and karyotyping. Results: We identified a male proband and a female patient that presented with the craniofacial characteristics of FXS, neuropsychomotor developmental delay, speech delay, intellectual deficit, and a positive molecular diagnosis of FXS. Interestingly, the female patient presented with a severe phenotype also associated with the presence of 8p23.1 deletion, while the proband patient presented a balanced translocation t(7;10)(p10;q24). Moreover, we detected multiple carriers of the FXS premutation in the family. Conclusions: To our knowledge, we describe for the first time the simultaneous occurrence of FXS and an 8p23.1 deletion and their possible synergistic effects on the phenotype of a female patient. Moreover, we describe the coexistence of FXS, an 8p23.1 deletion, and a balanced translocation t(7;10)(p10;q24) in the same family.

Background: Autosomal recessive congenital ichthyoses (ARCI) are inherited disorders produced by mutations in essential genes for the skin function. A low prevalence of this disease has been resported worldwide; however, in a recent study, we identified a large cluster of ARCI families who resided in the High Mountains Region from the Veracruz State, Mexico. Thus, we aimed to identify the causative mutation of ARCI and describe the high prevalence of this disease in this region., Methods: We selected seven familiar trios and performed whole-exome sequencing to identify the mutation associated with ARCI. To validate the identified mutation, we performed Sanger sequencing in 62 patients, 30 unaffected relatives, and 100 healthy volunteers. Finally, we performed molecular modeling to investigate the possible functional consequences produced by the mutation., Results: We identified a novel homozygous mutation (c.1054C>G [p.Pro352Ala]) in the exon 7 of the TGM1 gene in all the patients. We calculated a prevalence rate of ARCI of 74:100,000 (1:1,348) in the studied communities. Molecular modeling revealed that the mutation leads to a nonconservative amino acid substitution, which is very probably damaging to the protein structure/function., Conclusions: We report a novel mutation in the TGM1 gene in 62 Mexican patients. The unusually high frequency of this mutation suggests a founder effect; however, further haplotype analysis is necessary to corroborate this hypothesis. In this respect, to our knowledge, the prevalence of ARCI found in the studied communities is the highest observed worldwide., (© 2020 the International Society of Dermatology.)

Objective: To compare sexual negotiation levels and self-efficacy in male condom use in men and women., Methods: Comparative crosssectional study of undergraduate students carried out during the year 2018 in a private university in the city of Querétaro, Mexico. Non-probabilistic sampling was used. Measured variables included sociodemographic characteristics, risky sexual behaviors, negotiation skills and sexual self-efficacy for condom use. The Mann Whitney U test and non-parametric variance analysis (Kruskal - Wallis) were used., Results: Overall, 270 students were enrolled; 89.6% of university students were sexually active; the mean age of sexual activity initiation was 15.41 years. The average reported number of sexual partners was 4.2. In each sexual relation, 27.8% had used a condom. Differences were found between men and women in terms of sexual negotiation styles in the avoidance (p=0.04) and accommodation (p<0.00) domains, with higher scores for men compared to women. Women scored higher for self-efficacy in condom use (p<0.001)., Conclusions: The young university students interviewed engage in risky sexual activities. Women exhibit greater sexual self-efficacy as well as better skills at negotiating condom use. Strengthening public policies targeted to the student population for the prevention of risky sexual behavior is needed. Further studies on interventions aimed at building strong sexual negotiation and self-efficacy among adolescents are required., Competing Interests: None declared, (Copyright© 2020 This is an open-access article distributed under the terms of the Creative Commons Attribution License by-nc-nd/4.0.)

B cell-activating factor (BAFF) promotes the survival, proliferation and maturation of B lymphocytes, which are key elements in the pathogenesis of systemic lupus erythematosus (SLE). This cytokine is encoded on TNFSF13B gene, and diverse single-nucleotide polymorphisms have been associated with susceptibility in different autoimmune disorders. In this study, the relationship of TNFSF13B gene rs9514827T>C, rs1041567T>A and rs9514828C>T polymorphisms, mRNA expression and soluble BAFF levels was investigated in 175 SLE patients and 208 healthy controls (HC). The TNFSF13B polymorphisms were evaluated by PCR-RFLP technique. The TNFSF13B gene expression was quantified through the RT-PCR assays. The soluble BAFF (sBAFF) levels were measured with ELISA test. There were no differences in genotype and allele frequencies for the three TNFSF13B polymorphisms, between SLE patients and HC. SLE patients showed 3.15-fold more TNFSF13B gene expression than HC. The patients who displayed most mRNA expression were those with active disease and the carriers of rs9514828 T variant allele. The sBAFF serum levels were higher in SLE patients compared to HC (2.083 vs. 0.742 ng/mL, p < 0.001). The SLE patients with active disease showed the higher sBAFF serum levels (2.403 ng/mL), mainly patients with lupus nephritis and hematological manifestations. In addition, a correlation of sBAFF with disease activity was found (r = 0.32, p < 0.001). In conclusion, the TNFSF13B gene polymorphisms were not found to be associated with SLE susceptibility in Mexican mestizos. Nevertheless, rs9514828C>T polymorphism seems to increase TNFSF13B gene expression. High BAFF expression is related to active disease, renal and hematological involvement; therefore, it could be considered as follow-up biomarker in SLE patients.

Enterotoxigenic (ETEC) and enteroaggregative Escherichia coli (EAEC) pathotypes are important etiological agents causative of diarrhea in children younger than 5 years of age in Mexico and in developing countries, where they cause numerous deaths. Both have been associated with delayed growth in children and are the main causative agents of traveler's diarrhea. The pathogenesis of both bacteria starts by adhering to the intestinal epithelium by means of fimbriae, called colonization factors in human ETEC isolates and aggregative adherence fimbriae in EAEC isolates. Once ETEC adheres to the enterocyte, it produces one or both of its toxins and induces the secretion of chloride and sodium ions and water into the intestinal lumen, producing its characteristic watery diarrhea. EAEC binds to the intestinal epithelium forming a biofilm, induces the production of mucus, releases its toxins and promotes inflammation. EAEC and ETEC infection models with wild-type C57BL/6 and CD40 ligand-deficient mice (with intact microbiota), respectively, revealed that undernutrition and low-zinc diet increases EAEC infection, causing growth retardation, and that ETEC colonizes, persists and induces local and systemic humoral immune response., (Copyright: © 2019 Permanyer.)

Background and Objectives: Substance use disorders (SUDs) have high comorbidities with psychiatric disorders. Childhood and adolescence are particularly vulnerable developmental periods for the onset of SUDs. The objective of this study was to explore the differences, if any, between Mexican adolescents and young adults with respect to the prevalences of groups of psychiatric disorders, the types of substances used and the social factors involved., Methods: This cross-sectional study included 781 patients evaluated at the Youth Integration Center in Mexico City. The diagnostic criteria for SUDs and psychiatric disorders were defined according to the DSM-IV and ICD-10. Associations between SUDs and psychiatric disorders were evaluated via multivariate analysis using logistic regression models., Results: The adolescents were more frequently substance abusers, whereas the adults had legal problems more often than the adolescents. We showed that adolescents using inhalants or cocaine were 1.62 more likely to have attention deficit hyperactivity disorder (ADHD). Moreover, adults using inhalants were 3.33 times more likely to meet the criteria for a psychotic disorder., Discussion and Conclusions: We found that adolescents diagnosed with ADHD were more likely to have problems with use or abuse of or dependence on inhalants, and an elevated prevalence of parental SUDs was found in both the adolescent and adult groups., Scientific Significance: Our findings indicate that earlier diagnosis and intervention are necessary in adolescents with ADHD and/or parental SUDs to prevent more advanced psychiatric diseases and adverse social consequences during adulthood. (Am J Addict 2018;XX:1-7)., (© 2018 American Academy of Addiction Psychiatry.)

Spinocerebellar ataxia type 7 (SCA7) is an inherited neurodegenerative disorder characterized by progressive cerebellar ataxia associated with macular degeneration. We recently described one of the largest series of patients with SCA7 that originated from a founder effect in a Mexican population, which allowed us to perform herein the first comprehensive clinical, neurophysiological, and genetic characterization of Mexican patients with SCA7. In this study, 50 patients, categorized into adult or early phenotype, were clinically assessed using standard neurological exams and genotyped using fluorescent PCR and capillary electrophoresis. Patients with SCA7 exhibited the classical phenotype of the disease characterized by cerebellar ataxia and visual loss; however, we reported, for the first time, frontal-executive disorders and altered sensory-motor peripheral neuropathy in these patients. Semiquantitative analysis of ataxia-associated symptoms was performed using Scale for the Assessment and Rating of Ataxia (SARA) and the Brief Ataxia Rating Scale (BARS) scores, while extracerebellar features were measured employing the Inventory of Non-ataxia Symptoms (INAS) scale. Ataxia rating scales confirmed the critical role size of cytosine-adenine-guanine (CAG) repeat size on age at onset and disease severity, while analysis of CAG repeat instability showed that paternal rather than maternal transmission led to greater instability.

Tropical gar (Atractosteus tropicus) is an economically and socially important freshwater species from Southeastern Mexico, with a high aquaculture potential. With this in mind, the purpose of this study was to characterize the digestive proteases of tropical gar juveniles through biochemical and electrophoretic analyses. Twenty specimens with an average weight of 73.6 ± 12.7 g were used to obtain stomach and intestinal tissue from which multienzymatic extracts were prepared. The general activities of the acid and alkaline proteases were evaluated, as well as the specific activities of trypsin, chymotrypsin, leucine aminopeptidase and carboxypeptidase A. The effect of the pH and temperature on the proteases was also analyzed, together with the composition of the multienzymatic extracts using protease inhibitors and electrophoretic tests. Results showed that A. tropicus have a functional stomach in which protein hydrolysis starts with pepsin and which contains endo- and exopeptidases (trypsin, chymotrypsin, leucine aminopeptidase and carboxypeptidase A) and proteases that are resistant to high temperatures (45 and 55 °C for alkaline and acid proteases, respectively) and pH values. Using zymogram technique, we found two acid protease isoforms (0.35 and 0.71 rf) and five alkaline protease isoforms (83.7, 43.7, 27.5, 24.0 and 19.4 kDa), which decrease or disappear with the different inhibitors. Thus, this species is considered to be a carnivore capable of adapting to its environment by consuming different types of proteins from preys and also could adapt rapidly to consume a compound diet with different animal protein sources.

Introduction: Charcot-Marie-Tooth disease (CMT) is a neuropathy that affects sensory and motor nerves. The most common CMT subtype is CMT1A due to a PMP22 duplication of a 1.5 Mb fragment on the 17p11.2-p12. The development of a specific molecular technique that detects the PMP22 duplication is necessary for the diagnosis of CMT1A., Aim: To establish a routinary test for detection of the PMP22 gene duplication in Mexican population and to estimate the CMT1A frequency in patients clinically diagnosed as CMT., Patients and Methods: A cohort of 157 individuals clinically diagnosed as CMT were analyzed. The detection of the PMP22 gene duplication was performed using the comparative 2-ΔΔCT qPCR method., Results: The comparative 2-ΔΔCT method was sensitive and reliable for the detection of the PMP22 duplication. In order to validate the testing, data was compared with FISH results. Duplication of PMP22 was detected in 79 patients (50.3%). Although CMT1A frequency is different among populations, in Mexican patients it was similar with other populations such as United States, Australia, Finland, Sweden and Spain., Conclusions: The qPCR technique is an accurate and inexpensive method for the diagnosis of CMT1A. This method can be routinely used in Mexico where CMT1A represents ≍ 50% of CMT cases. Molecular diagnosis of CMT1A is essential for the genetic counseling and treatment of patients.

Background: Identification of historic pathogens is challenging since false positives and negatives are a serious risk. Environmental non-pathogenic contaminants are ubiquitous. Furthermore, public genetic databases contain limited information regarding these species. High-throughput sequencing may help reliably detect and identify historic pathogens., Results: We shotgun-sequenced 8 16th-century Mixtec individuals from the site of Teposcolula Yucundaa (Oaxaca, Mexico) who are reported to have died from the huey cocoliztli ('Great Pestilence' in Nahautl), an unknown disease that decimated native Mexican populations during the Spanish colonial period, in order to identify the pathogen. Comparison of these sequences with those deriving from the surrounding soil and from 4 precontact individuals from the site found a wide variety of contaminant organisms that confounded analyses. Without the comparative sequence data from the precontact individuals and soil, false positives for Yersinia pestis and rickettsiosis could have been reported., Conclusions: False positives and negatives remain problematic in ancient DNA analyses despite the application of high-throughput sequencing. Our results suggest that several studies claiming the discovery of ancient pathogens may need further verification. Additionally, true single molecule sequencing's short read lengths, inability to sequence through DNA lesions, and limited ancient-DNA-specific technical development hinder its application to palaeopathology.

Spinocerebellar ataxias (SCA) are a heterogeneous group of neurodegenerative disorders. CAG (cytosine-adenine-guanine) trinucleotide repeat expansions in the causative genes have been identified as the cause of different SCA. In this study, we simultaneously genotyped SCA1, SCA2, SCA3, SCA6, and SCA7 applying a fluorescent multiplex polymerase chain reaction assay. We analyzed 10 families with SCA (64 patients) from five different communities of Veracruz, a Mexican southeastern state, and identified 55 patients for SCA7 and 9 for SCA2, but none for SCA1, SCA3, or SCA6. To our knowledge, this sample represents one of the largest series of SCA7 cases reported worldwide. Genotyping of 300 healthy individuals from Mexican population and compiled data from different ethnicities showed discordant results concerning the hypothesis that SCA disease alleles arise by expansion of large normal alleles., (© 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Spinocerebellar ataxia type 7 (SCA7) is a neurodegenerative disorder characterized by progressive cerebellar ataxia associated with macular degeneration that leads, in the majority of patients, to loss of autonomy and blindness. The cause of the disease has been identified as (CAG) n repeat expansion in the coding sequence of the ATXN7 gene on chromosome 3p21.1. SCA7 is one of the least common genetically verified autosomal dominant cerebellar ataxias found worldwide; however, we previously identified the Mexican population showing high prevalence of SCA7, suggesting the occurrence of a common founder effect. In this study, haplotype analysis using four SCA7 gene-linked markers revealed that all 72 SCA7 carriers studied share a common haplotype, A-254-82-98, for the intragenic marker 3145G/A and centromeric markers D3S1287, D3S1228, and D3S3635, respectively. This multiloci combination is uncommon in healthy relatives and Mexican general population, suggesting that a single ancestral mutation is responsible for all SCA7 cases in this population. Furthermore, genotyping using 17 short tandem repeat markers from the non-recombining region of the Y chromosome and further phylogenetic relationship analysis revealed that Mexican patients possess the Western European ancestry, which might trace the SCA7 ancestral mutation to that world region.

Exposure to environmental tobacco smoke (ETS) during early childhood increases the risk of developing asthma. The intention of this study was to genotype a population of children from Coahuila state in Northern Mexico and to determine whether polymorphisms of the CYP1A1, GSTP1, and IL13 genes are associated with exposure to ETS and subsequently a higher risk for asthma. IL13 plays an important role in the development of allergic response, particularly those related with airway inflammation. CYP1A1 and GSTP1 are xenobiotic-metabolizing enzymes induced by repeated exposure to toxicants. Polymorphisms of these genes have been related with ETS exposure and increased risk for asthma. To assess the effect of IL13 (-1112 C>T and Arg110Gln), GSTP1 (Ile105Val), and CYP1A1 (Ile462Val) on asthma risk and ETS exposure, we recruited 201 unrelated children and classified them into four groups: (1) control without ETS exposure; (2) control with ETS exposure; (3) with asthma and with ETS exposure and (4) with asthma and without ETS exposure. No association among ETS exposure, asthma, and the studied polymorphisms was denoted by multivariate analysis of this population., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Myotonic dystrophy type 1 (DM1), the most common form of adult muscular dystrophy, is caused by anormal expansion of CTG trinucleotide repeats located in the 3'-untranslated region of the DMPK gene. The clinical features of DM1 are multisystemic and highly variable, and the unstable nature of CTG expansion causes wide genotypic and phenotypic presentations. In this study, we described to our knowledge for the first time the molecular diagnosis of myotonic dystrophy type 1 patients in the Mexican population, applying a fluorescent PCR method in combination with capillary electrophoresis analysis of the amplified products. We identified expanded alleles in 45 out of 50 patients (90%) with clinical features of myotonic disease. Furthermore, genotyping of 400 healthy subjects revealed the presence of 25 different alleles, ranging in size from 5 to 34 repeats. The most frequent allele was 13 CTG repeats (38.87%) and the frequency for alleles over 18 CTG repeats was 6.7%. Molecular test is essential for DM1 diagnosis and distribution of the CTG repeat alleles present in the Mexican population are significantly different from those of other populations.

Background and Aims: Rhabdomyosarcoma (RMS) is a pediatric tumor whose classification is based on histological criteria according to two main subgroups, embryonal RMS (ERMS) and alveolar RMS (ARMS). The majority but not all ARMS carry the specific PAX3(7)/FKHR translocation. The type of translocation in patients with ARMS defines the prognosis., Methods: We retrospectively analyzed 30 cases of ARMS in Mexican patients and evaluated the fusion status of the genes using RT-PCR and fluorescence in situ hybridization (FISH) in formalin-fixed paraffin-embedded tissues (FFPET)., Results: From 25 samples (83%) with optimal RNA quality, RT-PCR revealed 15 cases (50%) with the t(2;13)/PAX3-FKHR. Only one case (3%) was positive to t(1;13)/PAX7-FKHR and nine cases (30%) were fusion-negative. Correspondingly, using FISH, the t(2;13)/PAX3-FKHR was found positive in 19 cases (63.5%), one case (3%) revealed the t(1;13)/PAX7/FKHR and ten cases (33.5%) were fusion-negative by this method. Five cases were not evaluable by RT-PCR but recovered by FISH. Only four of the total revealed t(2;13); the other was fusion-negative., Conclusions: FISH technique is more sensitive when FFPET is used to describe the chromosomal translocation of ARMS. These Latino patients showed an association of the t(2;13) in older patients (mean: 9 years) and negative translocation in younger patients (mean: 4 years) (p <0.05). Both t(2;13) and negative-fusion were present in patients with clinical stages III and IV (p <0.05). There was a nonsignificant trend of t(2;13) to lower overall survival than negative-fusion status., (Copyright 2010 IMSS. Published by Elsevier Inc. All rights reserved.)

Aims: To screen for Bacillus thuringiensis strains from avocado orchards in two Mexican states with lepidopteran-specific cry gene content and evaluate their insecticidal activity against Argyrotaenia sp., an undescribed species present in avocado orchards., Methods and Results: Lepidopteran-active cry1, cry2 and cry9 genes were detected by PCR analysis in 37 isolates. cry1 genes were more frequent in Michoacán, but were undetected in Nayarit isolates. cry9 and cry2 genes were detected in isolates from both states, although cry2 genes were less frequent. A variety of crystal shapes were observed among the isolates. According to gene profile, eight isolates were selected and tested against 2-day old Argyrotaenia sp. larvae. Standard strain HD-125 caused the highest mortality followed by strain MR-26 from Michoacán at a concentration of 500 microg ml(-1), respectively., Conclusions: Bacillus thuringiensis strains isolated from avocado orchards exhibit a low toxic activity towards Argyrotaenia sp. larvae, in spite of their specific cry gene content., Significance and Impact of the Study: Toxic activity of B. thuringiensis is not necessarily related to insect pest habitat and neither to specific cry gene content associated to other lepidopterans.

Background: Charcot-Marie-Tooth (CMT) is the most common inherited disorder of the human peripheral nerve. The mos tfrequent subtype, CMT1A, is associated with duplication of approximately 1.5 Mb fragment in 17p11-p12, that includes the PMP22 gene., Objective: The aim of this study was to describe different strategies used for clinical and molecular CNT1A diagnoses among patients attending the National Rehabilitation Institute of Mexico (INR)., Material and Methods: 17 patients had clinical and electrophysiological features compatible with CMT1. A molecular study using capillary electrophoresis (CE) was performed and a PMP22 gene duplication was detected, Results: Clinical, biochemical and electrophysiological studies constituted the inclusion criteria to establish a CMT1 diagnosis. With CE the duplication of the PMP22 gene was observable and we established a possible CMT1A diagnosis in seven patients. All duplications detected by capillary electrophoresis were corroborated using FISH., Conclusion: CE is a feasible and reliable method to detect PMP22 gene duplication. Using different clinical, electrophysiological and molecular strategies in this patient population allowed us to establish an accurate diagnosis and offer suitable genetic counseling.

Background: Breast cancer is one of the most frequent causes of death in Mexican women over 35 years of age. At molecular level, changes in many genetic networks have been reported as associated with this neoplasia. To analyze these changes, we determined gene expression profiles of tumors from Mexican women with breast cancer at different stages and compared these with those of normal breast tissue samples., Methods: 32P-radiolabeled cDNA was synthesized by reverse transcription of mRNA from fresh sporadic breast tumor biopsies, as well as normal breast tissue. cDNA probes were hybridized to microarrays and expression levels registered using a phosphorimager. Expression levels of some genes were validated by real time RT-PCR and immunohistochemical assays., Results: We identified two subgroups of tumors according to their expression profiles, probably related with cancer progression. Ten genes, unexpressed in normal tissue, were turned on in some tumors. We found consistent high expression of Bik gene in 14/15 tumors with predominant cytoplasmic distribution., Conclusion: Recently, the product of the Bik gene has been associated with tumoral reversion in different neoplasic cell lines, and was proposed as therapy to induce apoptosis in cancers, including breast tumors. Even though a relationship among genes, for example those from a particular pathway, can be observed through microarrays, this relationship might not be sufficient to assign a definitive role to Bik in development and progression of the neoplasia. The findings herein reported deserve further investigation.

A new cucullanid, Dichelyne bonacii n. sp., is described from the intestine of the grey snapper Lutjanus griseus and the stomach of the black grouper Mycteroperca bonaci off the coast of Yucatán. The absence of a ventral precloacal sucker and the presence of 11 pairs of caudal papillae in males allocate it to the subgenus Dichelyne. It differs from its congeners in body dimensions and by having two almost equal spicules (left 712-950 and right 722-945microm), two intestinal caeca and in the position of the deirids and excretory pore. Apparently, L. griseus acts as definitive host of this species, whereas M. bonaci may be considered as a postcyclic host. This new species represents the first record of a nematode of the subgenus Dichelyne in marine fishes of Mexico.

The abundance, population structure, and growth of the Pen-shell Atrina maura in the Corralero-Alotengo tropical lagoon system in Oaxaca, Mexico, were studied from February to September of 1997. An abundance analysis showed significant temporal and spatial differences (Kruskal-Wallis, p < 0.001). Two spatial groups of abundance were found in the area, one from the mouth of the lagoon system to the middle of the Pen-shell bank, and the other between the middle of the Pen-shell bank and the head of the system. Three temporal periods of abundance were found (February-April-May; July-August; March-June-September). The distribution of population size showed that benthic recruitment of A. maura occurred from February to July. Length frequency of A. maura is commonly wide-ranging; nevertheless, in this study Pen-shell organisms with a valve length of 15 cm were frequently found. The growth rate length was 3.7 cm/month during the dry season (February to May), and 3.5 cm/month during the rainy season (June to September). Sex ratio was maintained at 1:1 from February to May, but males were dominant from June to August, and the minimum length for reproduction was registered at 10 cm valve length.