QUOTE(sniegosunys @ 2008 07 14, 11:36)
o jei kaip sakant tą sėklide "ištraukia" tai gali būti paveldima? Tokio patino palikuonys gali paveldėti tėvo jaunystės bėdą?
deja, bėda ne tik jaunystei, o visam gyvenimui... Apie tai, kad traukia visokiais masažiukais teko girdėti, bet kiek tai veiksminga?.. ir svarbiausia kam to reikia
Apie jokius palikuonis negali būt kalbos, nebent šeimininkai su pavažiavusiu stogu..
L. Zöldág D. Mendege K. Kontadakis:
SIGNIFICANCE OF CRYPTORCHISM IN DOG BREEDING
In four Hungarian kennels two German Shepherd, one West Highland White Terrier and one English Cocker Spaniel the incidence of cryptorchism, and the allelic population frequency of the hereditary disease was studied. The males were affected when the scrotal descent of testicles did not take place until six months of age. The inheritance of the disorder was proven by segregation analysis and pedigre diagrams (Figure 1., 2., 3. and 4.) in all of the inbred populations. Presuming an autosomal recessive (major) gene the population genotype frequencies (number of affected offspring, carriers and healthy individuals) were calculated by the Hardy-Weinberg rule. In three populations (I., II., III.) the rate of affected individuals was 19, 13 and 14%, of the carriers 48, 43 and 45%, and of healthy animals 33, 44 and 41% respectively. The high (nearly 50%) probable ratio of carriers proves high allele frequencies of this genetic disorder in all of these populations. As inheritence is sex limited, a high genotypic frequency is presumed in bitches as well (Table 1, 2, 3 and 4). Cryptorchism often occured linked with scrotal hernia, especially in the West Highland White Terrier breed, which raises the possibility of an unbalanced linkage in inheritence of the disorder. On the other hand the high ratio of affected males raises the question of an X-linked inheritence as well, which can be excluded by the absence of a hemizygous character and varied gene expression. Reduction of the incidence can be carried out by several breeding protocols: (1) by culling the affected animals and recognised carriers from the breeding, and (2) by using only healthy individuals in matings.
ir dar
Canine cryptorchism and subsequent testicular neoplasia: Case-control study with epidemiologic update
Howard M. Hayes Jr. 1, George P. Wilson 2, Thomas W. Pendergrass 3, Victor S. Cox 4
1Environmental Epidemiology Branch, National Cancer Institute, Bethesda, Maryland 20205
2Department of Veterinary Anatomy, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio 43210
3Departments of Pediatrics and Epidemiology, University of Washington, Seattle, Washington 98105
4Department of Veterinary Biology, University of Minnesota College of Veterinary Medicine, St. Paul, Minnesota 55108
Abstract
A retrospective study of 2,912 cryptorchid dogs identified 14 breeds with significantly high risk. Among six distinct closely interrelated breed groups (e.g., toy, miniature, and standard poodles), the risk in the smaller breed was always greater than that in the larger relative, suggesting that genetically influenced maldescent could be, in part, related to physical size or the rate of growth of the involved structures. Testicular tumors were diagnosed in 5.7% of the cryptorchid dogs; half had only Sertoli cell tumors, one-third had only seminomas. The relative risk for Sertoli cell tumor or seminoma was not directly related to a familial risk for cryptorchism. Using the health experience of a control population composed of male dogs with anal sac disease (N = 4,184), there is an estimated relative risk of 9.2 in cryptorchid dogs to develop a testis tumor (95% confidence interval, 5.9-14.3) and 4.2 in dogs with inguinal hernia (95% confidence interval, 1.8-9.5). Considering that the anatomical development of the genital tract, testis descent, and tunic relationships in dog are very similar to that in man, and that the associations of cryptorchism and inguinal hernia with testis neoplasms are also similar, the dog should be an excellent model system to further investigate the causes of human cryptorchism.
