RESUMO
BACKGROUND: Deafness in dogs is frequently associated with the pigment genes piebald and merle. Little is known about the prevalence of deafness in dogs carrying the merle allele. OBJECTIVE: To determine the prevalence of deafness in dogs heterozygous and homozygous for the merle allele of the mouse Silver pigment locus homolog (SILV) gene. ANIMALS: One hundred and fifty-three privately owned merle dogs of different breeds and both sexes. METHODS: Hearing was tested by brainstem auditory-evoked response and classified as bilaterally hearing, unilaterally deaf, or bilaterally deaf. DNA from buccal cells was genotyped as either heterozygous or homozygous for the merle allele. Deafness association tests among merle genotype, eye color, and sex were performed by the chi(2) test. RESULTS: Deafness prevalence in merles overall was 4.6% unilaterally deaf and 4.6% bilaterally deaf. There was a significant association between hearing status and heterozygous versus homozygous merle genotype. For single merles (Mm), 2.7% were unilaterally deaf and 0.9% were bilaterally deaf. For double merles (MM), 10% were unilaterally deaf and 15% were bilaterally deaf. There was no significant association with eye color or sex. CONCLUSIONS: Deafness prevalence in merle dogs was greater than that in some dog breeds homozygous for the piebald gene, such as the English Cocker Spaniel, but comparable to, or lower than, that in the Dalmatian and white Bull Terrier. Dogs homozygous for the merle allele were significantly more likely to be deaf than heterozygotes.
Assuntos
Surdez/genética , Surdez/veterinária , Doenças do Cão/genética , Alelos , Animais , DNA/química , DNA/genética , Surdez/epidemiologia , Doenças do Cão/epidemiologia , Cães , Potenciais Evocados Auditivos do Tronco Encefálico/genética , Feminino , Genótipo , Masculino , Reação em Cadeia da Polimerase/veterinária , PrevalênciaRESUMO
The effect of "coping statements" on the rapidity of progress through desensitization hierarchies was examined in several cases of clinically significant anxiety-based disorders. Using a series of single-case experimental designs (relying heavily on an alternating treatments element), it was shown that (a) coping statements decrease the reported anxiety shown in desensitization, (b) these statements seem to produce greater behavioral gains outside the treatment sessions per unit of treatment time, (c) the coping statements gradually begin to generalize across stimuli and (d) their effects go beyond those due merely to distraction, competing behaviors, or general expectations. The present methodology may comprise an alternative method, more compatible with ongoing clinical work, for the investigation of cognitive treatments.
