CD43 regulates the threshold for T cell activation by targeting Cbl functions.

T cell (TC) activation requires the coordinated signaling of the T cell receptor (TCR) and coreceptor molecules, allowing TCs to respond to lower degrees of TCR occupancy. Coreceptor molecules set the threshold for TC activation by controlling different regulatory signaling loops. The Cbl family members prevent undesired activation of T cells by regulating TCR signals. In this report, we show that TC prestimulation by the CD43 coreceptor molecule before TCR engagement inhibits TCR-dependent c-Cbl tyrosine phosphorylation, c-Cbl interaction with the adapter molecule Crk-L and promotes Cbl-b degradation in a PKCθ-dependent manner. Consequently, the prolonged tyrosine phosphorylation and delayed degradation of ZAP-70 and of the ζ chain lead to enhanced mitogen-activated protein kinase activation and robust TC response. These data indicates that CD43-mediated signals lower the threshold for TC activation by restricting the c-Cbl and Cbl-b inhibitory effects on TCR signaling. In addition to the strength and duration of intracellular signals, our data underscore temporality with which certain molecules are engaged as yet another mechanism to fine tune TC signal quality, and ultimately immune function.

Renin gene haplotype diversity and linkage disequilibrium in two Mexican and one German population samples.

INTRODUCTION: Renin is the main rate-limiting enzyme in the renin-angiotensin-aldosterone system. Its gene, REN, is a candidate crucial factor in essential hypertension and cardiovascular disease. The aim of this study was to evaluate allele and haplotype distributions of REN polymorphisms, and to estimate normalised linkage disequilibrium (D') in Mexican and German populations. MATERIALS AND METHODS: Four groups were studied for the REN single nucleotide polymorphisms (SNPs) 1205C>T, 1303G>A, and 10607G>A, in population samples of Mexican Mestizo (n = 86), Mexican Huichol (n = 49), German (n = 39), and individuals with hypertension diagnosis (n = 66). Polymorphisms were detected by PCR-RFLP. Genotype, allele and haplotype frequencies were estimated. RESULTS: SNP 1205C>T and 10607G>A allele and genotype distribution showed inter-group differences. The 1205T and 10607A allele showed a significance difference in hypertensive population. Haplotype analysis also showed some inter-group differences, especially in 1205C-1303G-10607G, 1205C-1303G-10607A and 1205T-1303G-10607G haplotypes. The segregation analysis disclosed complete linkage disequilibrium between 1205 and 1303 loci. CONCLUSION: These results provide an example of genetic diversity in related populations and illustrate the convenience of increasing the number of loci in associative studies between diseases and candidate genes.

[Population data of five STRs from the INTERPOL series in a mestizo population of western Mexico (State of Jalisco)]. / Datos poblacionales de cinco STRs de la serie INTERPOL en una población mestiza del Occidente de México.

INTRODUCTION: Short tandem repeats (STRs) are the DNA polymorphisms most widely used in forensic genetics and parentage testing. Most common series of STRs are those from FBI (CODIS) and from INTERPOL. While there are data related to the first group, no studies are still known in Mexican populations in regard of the INTERPOL set. OBJECTIVE: To describe the genetic characteristics of five INTERPOL STRs and to estimate their main forensic parameters in a population from western Mexico. MATERIAL AND METHODS: Samples from 100 random volunteers from the State of Jalisco were PCR typed for STRs F13B, D2S1338, FESFPS, Penta D and Penta E. RESULTS: Genotype proportions in all five STRs were in agreement with Hardy-Weinberg expectations (p > 0.05). Heterocygosity varied from 0.68 for FESFPS to 0.91 for Penta E markers. Power of discrimination (PD) and exclusion probability (EP) were in the 0.83-0.97 and 0.46-0.75 ranges, respectively. The five combined STRs give a PE > 0.99143 and PD > 0.99999. CONCLUSIONS: These results contribute to establish data bases representative of western Mexico and are useful in DNA forensic and parentage studies.

Population data and mutation rate of nine Y-STRs in a mestizo Mexican population from Guadalajara, Jalisco, México.

Nine Y-STR (DYS19, DYS390, DYS391, DYS392, DYS446, DYS447, DYS448, DYS456 and DYS458) were analyzed in a male sample of 285 unrelated individuals from Guadalajara, Jalisco, México. The haplotype diversity (0.996) and discrimination capacity (0.986) were calculated. A family study of around 200 father/son pairs and among 1828 meiosis showed five mutational events. All mutations were single step. The overall mutation rate estimated across the nine Y-STRs was 2.7 x 10(-3) (95% CI 1.2-6.4 x 10(-3))/locus/meiosis. The results indicate that these nine loci are useful Y-linked markers for forensic applications.

Genetic polymorphisms of the renin-angiotensin system in preterm delivery and premature rupture of membranes.

INTRODUCTION: Premature rupture of membranes (PRM) is a late pregnancy complication commonly associated with preterm delivery (PD). Although several markers related to the renin-angiotensin system (RAS) have been evaluated in certain pregnancy complications, only the angiotensin-converting enzyme (ACE) I/D variant has been studied in PD-PRM. The aim of this survey was to investigate the association of the polymorphisms (angiotensin II type 1 [AT1] receptor T174M and M235T, renin G2805A, ACE I/D and AT1-receptor A1166C) of the genes of RAS in women with PD-PRM. DESIGN: Deoxyribonucleic acid samples from 89 Mexican Mestizo women with PD and PRM and 224-288 controls were studied. Polymorphisms were analysed by polymerase chain reaction-restricted fragment length polymorphism or sequence specific primer assays. RESULTS: For all loci, genotype distribution was in agreement with Hardy-Weinberg expectations in the control group. Significant intergroup difference (case vs. control) was seen for angiotensinogen (AGT) M235T polymorphism, with an increased allele M235 in affected cases (50% vs. 40% in controls). Analysis of two-locus haplotype agrees with an independent segregation of physically unlinked genes. Haplotype AGT 174T-235M was also increased (50% vs. 40% in controls). CONCLUSIONS: Physically unlinked genes involved in RAS segregate independently. The AGT 174-235 region is associated with PD-PRM in this population.

[Assessment of five thrombophilic genetic polymorphisms among couples with habitual abortion]. / Evaluación de cinco polimorfismos de genes trombofílicos en parejas con aborto habitual.

An association between thrombophilic genes and obstetric conditions with early pregnancy termination has been previously proposed. In the present study we attempted to evaluate the possible association between thrombophilic genetic polymorphisms and habitual abortion (HA). Samples from two groups of volunteers were analyzed. The experimental group (n>100) was conformed by women attending the Centro Medico de Occidente, IMSS and their male couples, with a reproductive history ofat least three miscarriages. The reference group (n > 200) was composed by male and female healthy adults living in the state of Jalisco, Mexico. DNA was extracted from peripheral blood, and polymorphisms FII G20210A , FVG1691A, MTHFR C677T, ECA IID y TNF G-308A were typed by PCR-RFLP or -SSP. Genotype proportions in the reference group were in agreement with the HardyWeinberg expectations. Allele, genotype, and phenotype proportion inter-group comparisons did not show statistically significant differences. The present results could not demonstrate that thrombophilic polymorphisms constitute risk factors for HA in Jalisco.

Evaluación de cinco polimorfismos de genes trombofílicos en parejas con aborto habitual / Assessment of five thrombophilic genetic polymorphisms among couples with habitual abortion

Se han propuesto factores genéticos trombofílicos asociados con anormalidades obstétricas que implican la terminación temprana del embarazo. El propósito del estudio fue investigar la posible asociación de polimorfismos génicos trombofílicos con el aborto habitual (AH). Se analizaron muestras de dos grupos de personas que participaron voluntariamente en el estudio. El primero (n>100) consistió en mujeres atendidas en el Centro Médico de Occidente del Instituto Mexicano del Seguro Social y a sus parejas, por el antecedente reproductivo de por lo menos tres abortos idiopáticos (n>100). El grupo de referencia (n>200) lo formaron adultos sanos de ambos sexos residentes de Jalisco. El ADN se extrajo de una muestra de sangre periférica y se tipificaron, mediante PCR–RFLP o –SSP, los polimorfismos FII G20210A, FV G1691A, MTHFR C677T, ECA I/D y TNF G–308A. Las proporciones genotípicas en el grupo de referencia fueron similares a las predichas por la ley de Hardy–Weinberg y las comparaciones intergrupales alélicas, genotípicas y fenotípicas no mostraron diferencias significativas para ninguno de los polimorfismos estudiados. Estos resultados sugieren que los polimorfismos de los genes trombofílicos no representan un factor de riesgo para AH en nuestro medio.

An association between thrombophilic genes and obstetric conditions with early pregnancy termination has been previously proposed. In the present study we attempted to evaluate the possible association between thrombophilic genetic polymorphisms and habitual abortion (HA). Samples from two groups of volunteers were analyzed. The experimental group (n>100) was conformed by women attending the Centro Medico de Occidente, IMSS and their male couples, with a reproductive history ofat least three miscarriages. The reference group (n > 200) was composed by male and female healthy adults living in the state of Jalisco, Mexico. DNA was extracted from peripheral blood, and polymorphisms FII G20210A , FVG1691A, MTHFR C677T, ECA IID y TNF G-308A were typed by PCR-RFLP or -SSP. Genotype proportions in the reference group were in agreement with the HardyWeinberg expectations. Allele, genotype, and phenotype proportion inter-group comparisons did not show statistically significant differences. The present results could not demonstrate that thrombophilic polymorphisms constitute risk factors for HA in Jalisco.

[Meiotic and parental origin of extra chromosome 21 in children with regular trisomy 21]. / Origen meiótico y parental del cromosoma 21 extra en niños con trisomía 21 regular.

INTRODUCTION: Down syndrome (DS) or trisomy 21 is the most common chromosomal abnormality in live birth children. Most cases are regular trisomies 21 secondary to a maternal non-disjunction (ND). Meiotic and parental origins have been recently investigated by segregating genetic markers from DNA hypervariable regions. OBJECTIVE: To identify the meiotic and parental origin in children with regular trisomy 21. MATERIALS AND METHODS: There were analyze 20 groups of three (every group included parents and child with Down syndrome). There were used soothe following markers: D21S11, D21S1260, and D21S265. RESULTS: The ND occurred during the first meiotic division (M1) in 13 cases and at the second meiotic division (M2) in the other seven. Twelve out of the 13 NDs from the first group were maternal and one paternal. The parental origin within the M2 group was not elucidated. CONCLUSIONS: Meiotic origin was identified in all cases. As in other reports, the origin of trisomy 21 in the present population is mainly secondary to a maternal ND in M1.

HLA class II haplotypes in Mexican systemic lupus erythematosus patients.

Systemic lupus erythematosus (SLE) is an autoimmune disease in which polymorphisms within the human leukocyte antigen (HLA) region have been associated to its etiology. For this study, HLA-DQB1, DQA1, and DRB1 genes were typed by polymerase chain reaction-sequence-specific primer in 237 individuals, taken from 74 families, who had a member with SLE, and who had their residence in the western region of Mexico; as well as in 159 ethnically matched healthy volunteers taken from 32 families. Genotype and allele frequency analysis was performed in 74 SLE patients and 54 unrelated controls. Precise three-loci identification of independent haplotypes was performed in 48 patients and 54 controls by familial segregation. Genotype distribution at each loci was concordant with Hardy-Weinberg's equilibrium in the control group. In general, no genotype effect was observed in SLE patients. Allele distribution comparison showed in the SLE group a significant increase of HLA-DQA1*0102, DQB1*0402, and DRB1*15; whereas alleles HLA-DQB1*0303 and *0501 were significantly decreased. SLE patients showed haplotype DQB1*0602-DQA1-*0102-DRB1*15 increased. As expected, patients with SLE have a reduced haplotype genetic diversity. The associations found in this study are related to an ancestral haplotype that has been observed in SLE populations of different origins.

Thrombophilic polymorphisms in preterm delivery.

Single nucleotide polymorphisms tumor necrosis factor (TNF) G-308A, coagulation factors V G1691A and II G20210A, methylenetetrahydrofolate reductase (MTHFR) C677T, as well as the angiotensin-converting enzyme (ACE) insertion/deletion polymorphism were investigated in 86 women with a history of premature delivery (PD) and compared with those of a control group of adults from Guadalajara, Mexico (a minimum of 162 individuals were typed for each polymorphism). Significant differences in the frequency of these polymorphisms were found for MTHFR C677T (increased), and the ACE deletion (increased) among women who had a history of preterm delivery compared with controls. These polymorphisms therefore might be associated with PD.

Sensibilidad antimicrobiana in vitro de Streptococcus pyogenes aisaldo en infecciones respiratorias / Streptococcus pyogenes isolated from respiratory infections in vitro antimicrobial sensibility

Las infecciones agudas del tracto respiratorio constituyen un importante problema de salud, ya que representan la principal causa de morbilidad y mortalidad, sobre todo en edades pediátricas. Las bacterias causales han mostrado una marcada tendencia en los últimos años de resistencia a los antimicrobianos. Una notable excepción a este fenómeno ha sido Streptococcus pyogenes.Se estudió la susceptibilidad antimicrobiana de 312 cepas de S. pyogenes aisladas de infecciones del tracto respiratorio en el lapso de cinco años en el Laboratorio Clínico del Hospital de Infectología del Centro Médico Nacional "La Raza", a 12 diferentes antimicrobianos, utilizando la técnica de dilución en placa.Ninguna de las 312 cepas mostró resistencia a los antimicrobianos estudiados; las concentraciones inhibitorias mínimas variaron de acuerdo con éstos.De los antimicrobianos estudiados se consideró a la ampicilina como el antimicrobiano de elección para el tratamiento de las infecciones respiratorias causadas por S. pyogenes, por su espectro de actividad antimicrobiana, vía de administración, bajo costo y baja frecuencia de efectos colaterales

Patrones de suceptibilidad in vitro de organismos aislados en pacientes hospitalizados / In vitro susceptibility pattems of isolated organisms in hospitalized patients

Se compara la actividad in vitro de cefepime (una nueva cefalosporina parenteral de amplio espectro) contra la de ceftazidima, cefotaxima, piperacilina, ticarcilina-ácido clavulánico, impenem, gentamicina, amikacina yciprofloxina de 4,464 aislamientos bacterianos de diversos géneros grampositivos y gramnegativos, aislados del mismo número de pacintes de uno y otro sexo y de todas las edades, con infecciones bacterianas graves, como: sepsis, neumonías, celulitis, meningitis, etc. Para la identificación y caracterización de los aislamientos se utilizó un equipo automatizado y una técnica de microdilución en caldo para las pruebas de susceptibilidad. La tasa de susceptibilidad total para cefepime, contra todos los aislamientos, fue de 95.5 por ciento, comparado con imipenem de 92.5 por ciento, cifroploxacina 86.9 por ciento, amikacina 85.8 por ciento, y tan sólo del 68.0 por ciento para ceftriaxona. Cefepime fue muy activo contra en terobactriáces, Pseudomonas aeruginosa, Staphylococcus aureus, Acinetobacter sp. y Haemophilus influenzae, incluyendo a la mayor parte de los patógenos nosocomiales resistentes a las cefalosporinas de tercera generación

Estudio comparativo de la sensibilidad in vitro a aminoglucósidos / A comparative study of sensitivity in vitro of aminoglycoside

Se analizó la susceptibilidad in vitro de 6200 cepas bacterianas de gérmenes gramnegativos, aislados de diversos procesos infecciosos en pacientes atendidos en dos Hospitales del Centro Médico ®La Raza¼, con una técnica automatizada y computarizada, hacia diversos antibióticos. Los antibióticos del grupo de los Aminoglucósidos mostraron una mayor actividad antibacteriana que la observada con otros grupos de antimicrobianos estudiados. Los Aminoglucósidos continúan representando una buena alternativa terapéutica particularmente contra los gérmenes gramnegativos adquiridos intrahospitalariamente