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Biomedical subjects

C Hom

Publications and source records attributed to C Hom.

5 recordsLinked to original sources

Ankle stance angle: a functional index for the evaluation of sciatic nerve recovery after complete transection.

This study attempted to develop a motor functional index, ankle stance angle (ASA), to assess rat sciatic nerve regeneration subsequent to autografting. ASA, 50 degrees in normal rats, is the ankle joint angle at the mid-stance phase of the gait cycle. In a nerve graft group, a 1-cm segment of the right sciatic nerve was transected and then repaired with nerve autograft. In an ungrafted group, the nerve gap was left unrepaired. ASA measured 4 months after surgery was statistically significantly larger in the nerve graft group (36 degrees) than in the ungrafted group (22 degrees). The results suggest that ASA is more sensitive than sciatic function index in detecting functional recovery after a complete sciatic nerve lesion. ASA also showed a significant correlation with the passive range of ankle joint motion and gastrocnemius muscle weight. The study concluded that ASA is a reliable index for assessment of regeneration of rat sciatic nerve after a complete lesion. The intra-rater reliability (r = 0.97 and 0.90) and inter-rater reliability (r = 0.85) tests performed support the conclusions.

Animals

Heterogeneity of gamma-crystallins from spiny dogfish (Squalus acanthias) eye lens.

Mammalian lenses contain multiple gamma-crystallin gene products, which are differentially synthesized during lens development. We now report the isolation and characterization of multiple gamma-crystallins from lenses of adult spiny dogfish (Squalus acanthias) aged about 20-30 years. About 50% of total lens protein solubilized in 50 mM phosphate, pH 7.0; about 25% of this soluble fraction consists of gamma-crystallins as determined by gel filtration. These gamma-crystallins appear homogeneous with respect to molecular weight (approximately equal to 20,000) on SDS-polyacrylamide gels, but their isoelectric points range from below pH 6 to above 10. Preparative cation-exchange chromatography on SP-Sephadex at pH 4.8 resolves four major subfractions, while anion-exchange on DEAE-cellulose at pH 9.5 resolves seven subfractions. Although these procedures separate basic from acidic polypeptides, most of these gamma-crystallin subfractions still consist of polypeptide mixtures, as determined by ion-exchange HPLC and isoelectric focusing. Analytical cation-exchange HPLC on SynChropak CM300 at pH 6.0 resolves at least 10 different gamma-crystallin components. Amino acid compositions of all the subfractions are similar, yet distinct in the sense that three subclasses can be distinguished. Sulfhydryl residues range from three to six per chain, most of which are buried. The large heterogeneity of gamma-crystallins in adult lens may result from different gene products in combination with post-translational modification.

Amino Acids

Half-life of murine IgE antibodies in the mouse.

The half-life of intravenously injected murine anti-DNP IgE antibody was determined in recipient mice by sequential bleeding and was found to be 12 h. Intradermally injected IgE antibody persisted much longer, the half-life was 6 days.

Animals