Frequency of canine degenerative myelopathy SOD1:c.118G>A mutation in 22 dog breeds in Guadalajara, Mexico / Frecuencia de la mutación SOD1:c.118G>A de mielopatía degenerativa canina en 22 razas de perros en Guadalajara, México / Frequência da mutação SOD1: c.118G>A de mielopatía degenerativa canina em 22 raças de cães no Guadalajara, México

Abstract Background: Canine degenerative myelopathy (DM) is a late-onset disease that primarily affects large-breed dogs. The disease involves the spinal cord and produces progressive paresia and, eventually, complete loss of mobility. DM has been related to missense mutation c.118G>A in the SOD1 gene. Objective: To determine the genotypic and genic frequencies of DM in Mexico. Methods: In total, 330 samples from 22 different dog breeds were genotyped using the polymerase chain reaction and restriction fragment length polymorphisms (PCR-RFLP) technique. Results: The mutation was identified in 71 animals from 11 different breeds. Observed genic frequencies were 0.78 for the G allele and 0.14 for the A allele. Genotypic frequencies were 0.79 for the G/G wild-type, 0.14 for the G/A heterozygote, and 0.7 for the A/A homozygote. Conclusion: The genic frequency of this allele is high among the studied populations. A molecular marker program that identifies the DM mutation in breeding dogs should be implemented in order to reduce this frequency.

Resumen Antecedentes: La mielopatía degenerativa canina (MD) es una enfermedad progresiva de presentación tardía que afecta a la médula espinal, generalmente en caninos de razas grandes, y que produce paresis progresiva y eventual pérdida completa de la movilidad. Se ha relacionado con una mutación puntual por sustitución de bases en el gen SOD1 recientemente identificado como c.118G>A. Objetivo: Determinar las frecuencias genotípicas y génicas para la presentación de DM en México. Métodos: Se genotipificaron 330 muestras de perros de 22 razas mediante la técnica de reacción en cadena de la polimerasa y polimorfismos de longitud de fragmentos de restricción (PCR- RFLPs). Resultados: Se identificó la mutación en 71 animales de 11 razas diferentes. Las frecuencias génicas encontradas fueron de 0,78 para el alelo G y de 0,14 para el alelo A. Las frecuencias genotípicas fueron de 0,79 para el tipo silvestre G/G, 0,14 para el heterocigoto G/A y 0,7 para el homocigoto A/A. Conclusión: La frecuencia encontrada para la mutación es alta en las poblaciones estudiadas. La aplicación de un programa de selección asistida por marcadores moleculares contra la mutación causante de MDC en perros reproductores resultaría útil para reducir su frecuencia.

Resumo Antecedentes: A mielopatía degenerativa canina (MD) é uma doença progressiva de apresentação tardia que afeta a medula espinal geralmente de caninos de raças grandes e que produz paresia progressiva e eventualmente a perda completa da mobilidade. Tem sido relacionada com uma mutação pontual por substituição de bases no gen SOD1, recentemente identificado como c.118G>A. Objetivo: Determinar as frequências genotípicas e genéticas para a apresentação de DM no México. Métodos: Genotipagem de 330 amostras de cães de 22 raças por meio da técnica de reação em cadeia da polimerase e polimorfismos no comprimento de fragmentos de restrição (PCR- RFLPs). Resultados: A mutação foi identificada em 71 animais de 11 raças diferentes. As frequências gênicas encontradas foram de 0,78 para o alelo G e de 0,14 para o alelo A. As frequências genotípicas foram de 0,79 para o tipo silvestre G/G, 0,14 para o heterozigoto G/A e 0,7 para o homozigoto A/A. Conclusão: A frequência encontrada para a mutação é alta nas populações estudadas. A implementação de um programa de seleção assistida por marcadores moleculares contra a mutação que causa MDC seria útil para reduzir a sua frequência.

Development and validation of PCR-based assays for diagnosis of American cutaneous leishmaniasis and identificatio nof the parasite species

In this study, PCR assays targeting different Leishmania heat-shock protein 70 gene (hsp70) regions, producing fragments ranging in size from 230-390 bp were developed and evaluated to determine their potential as a tool for the specific molecular diagnosis of cutaneous leishmaniasis (CL). A total of 70 Leishmania strains were analysed, including seven reference strains (RS) and 63 previously typed strains. Analysis of the RS indicated a specific region of 234 bp in the hsp70 gene as a valid target that was highly sensitive for detection of Leishmania species DNA with capacity of distinguishing all analyzed species, after polymerase chain reaction-restriction fragment length polymorfism (PCR-RFLP). This PCR assay was compared with other PCR targets used for the molecular diagnosis of leishmaniasis: hsp70 (1400-bp region), internal transcribed spacer (ITS)1 and glucose-6-phosphate dehydrogenase (G6pd). A good agreement among the methods was observed concerning the Leishmania species identification. Moreover, to evaluate the potential for molecular diagnosis, we compared the PCR targets hsp70-234 bp, ITS1, G6pd and mkDNA using a panel of 99 DNA samples from tissue fragments collected from patients with confirmed CL. Both PCR-hsp70-234 bp and PCR-ITS1 detected Leishmania DNA in more than 70% of the samples. However, using hsp70-234 bp PCR-RFLP, identification of all of the Leishmania species associated with CL in Brazil can be achieved employing a simpler and cheaper electrophoresis protocol.

Molecular Genetic Study on Human Meningiomas:Loss of Heterozygosity on Chromosome 22

With the methods of restriction fragment length polymorphisms(RFLPs) and Southern blot, we performed a molecular genetic study in 20 cases of intracranial meningiomas. There were four cases of invasive meningiomas, two cases of recurrent meningiomas and one case of central neurofibromatsis. Comparison of the alleles detected by DNA probes in normal versus tumor DNA revealed chromosomal alteration. The following probes were used : ESR(chromosome 6q), pYN22, pYNH37.3(chromosome 17p), cEFD52(chromosome 17q), D22S10, IGLC2(chromosome 22q). In seventeen of 20 cases(85%), constitutional heterozygosity was observed for IGLC2 probe on chromosome 22q and loss of heterozygosity was detected in nine of 17 informative cases(53%). There was no loss of heterozygosity for other probes. Three of 4 cases of invasive meningiomas and one case of central neruofibromatosis displayed loss of heterozygosity.

RFLPs ANALYSIS OF DIGOXIGENIN-LABELLED pAW101 PROBE AND ITS PRACTICAL USES / 中国法医学杂志

A new method to revel RFLPs is presented. The human genomic DNAwas purified by saturatedNaCl solution and the pAW101 probe labelled with digoxigenin-dUTP. The relationships of RFLPsand genetic patterns of PGM1 (phosphoglucomutase),EsD (esterase D),GLO1 (glyoxalase)and ACP(acid phosphatase ) between the fillal generation and parental generation were detected in 15 families(among them 11 cases were aborted fetuses). The probability of paternity (w)was caculated accor-ding to Essen - Moller's formula, each w vlua was over 99. 73 %, reached the standard of incladingpaternity. An effective,rapid, and non-toxic RFLPs technique was established, which is easy to man-age in common lab oratories.