Objective To verify the possibility and exactly of ultrasound diagnosing peripheral nerve injection injury,by high-frequency ultrund observing the rabbits' injection injured sciatic nerve and contrasting with pathology.Methods Twenty-two rabbits were enrolled in this study,anesthetized by injected phenobarbital sodium through the ear edge vein.The rabbits' left sciatic nerve were punctured and cidomycin was injected by ultrasound guided.Ultrasound examination on the left sciatic nerve was performed at different time.After each examination 2 rabbits were killed and dissected the affected limb.The sciatic nerve was observed by eyes and under microscope.Results After injection,the sciatic nerves' outer diameter,inner diameter,thickness of the epineurium,the proportion of epineurium was increased (P ＜ 0.05),internal echo of the nerves was reduced (P ＜ 0.05),epineurium became rough (P ＜ 0.05),demarcation with surrounding tissue became gradually fuzzy (P ＜ 0.05),the nerves became rigid (P ＜ 0.05).Observed by microcrope,after injection,hyperemia and hemorrhage of endoneurium and epineurium,inflammatory cell infiltration,damaged nerve fiber structures,desmoplasia inside and outside nerve can be seen.Conclusions The sonogram of injection injured nerve vary in different periods,and related with pathological changes.High-frequency ultrasound is a reliable imaging method of diagnosing sciatic nerve injection injury.

Objective To study the relation between point mutations at nt3243 and nt8344 of muscle mitochondrial DNA from patients with mitochondrial encephalomyopathies and phenotypes. Methods DNA was extracted from muscle specimens from 5 patients with mitochondrial encephalomyopathies and amplified by PCR method, using corresponding oligonucleotide primers. DNA fragments were digested with restriction enzymes BglⅠ and ApaⅠ, then the digested DNA fragments were analyzed with an electrophoresis method.Results The point mutation at nt3243 of mtDNA was found in 2 patients, one with mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS) and another with myoclonic epilepsy with ragged red fibers (MERRF). The point mutation at nt8344 was found in 2 patients with MERRF, including the one with point mutation at nt3243.Conclusion The point mutation of DNA at nt3243 correlated with MELAS and nt8344 correlated with MERRF. In addition, the detection of point mutations at both nt3243 and nt8344 in a patient with MERRF shows the association of mutation with diversity in clinical manifestations of mitochondrial encephalomyopathies.