Pathology of Avascular Necrosis in the Femoral Head of Spontaneously Hypertensive Rats

Naturally occurring avascular necrosis in the femoral head of SHR, which resembles Perthes\u27 disease in man, was observed histologically. Of 96 epiphyses from 48 SHR, 34 epiphyses from 27 SHR showed a hallmark of necrosis during the period of 10 to 40 weeks after birth. The complete necrosis over the whole epiphyseal nucleus without revascularization was seen at the age of 10 and 15 weeks. Then the necrotic epiphysis was gradually repaired by the invasion of vascularized granulation tissue, and finally the healing of the necrosis was complete before the age of 40 weeks. An investigation into the pathogenesis of the healing infarction seemed that it would be of use in elucidating the cause of Perthes\u27 disease

Phylogenetic and Taxonomic Relationships of Northern Far Eastern Phoxinin Minnows, Phoxinus and Rhynchocypris (Pisces, Cyprinidae), as Inferred from Allozyme and Mitochondrial 16S rRNA Sequence Analyses

Analyses of allozyme (18 loci) and partial mitochondrial DNA (mtDNA) sequences (1295 bp, 16S rRNA) support the classification of phoxinin minnows from the northern Far East into 2 genera of 8 species: Phoxinus phoxinus, Rhynchocypris oxycephalus, R. perenurus, R. czekanowskii, R. kumgangensis, R. semotilus, R. lagowskii and R. sp. (bergi ?). Although R. lagowskii from Japan and the Amur basin and R. sp. from Vladivostok region to Korea have been classified into a single species by many authors as R. lagowskii, they form separate clusters in both analyses, suggesting different specific status. Some R. oxycephalus and R. perenurus had the mtDNA haplotypes of R. lagowskii and R. czekanowskii, respectively, which probably indicates that local introgression of mtDNA occurred through inter-specific hybridization. Rhynchocypris forms a monophyletic cluster with dace genera Tribolodon and Pseudaspius, not with Phoxinus. Eurasian and American Phoxinus are suggested to be paraphyletic