Patellar location changes following EMG biofeedback or progressive resistive exercises.

Changes in the patellofemoral congruence (PFC) angle, the patellar rotation (PR) angle, and the sulcus angle following EMG biofeedback training that emphasized vastus medialis obliquus strengthening, the Daily Adjustable Progressive Resistive Exercise (DAPRE) technique, or no exercise were studied. Subjects were 30 normal, college females. The EMG biofeedback group and the DAPRE group followed established protocols for a 3-wk training period. The control group refrained from exercise. Patellar angles were determined with x-rays both pre- and posttest with the quadriceps relaxed and contracted. Reliability of the x-rays was determined with a correlation matrix of pre- and posttest sulcus angle measurements (P less than 0.001). EMG biofeedback training resulted in significant changes in the PFC angle with the quadriceps contracted (P less than 0.05). DAPRE resulted in significant changes in the PR angle with the quadriceps contracted (P less than 0.05). The results of this study suggest that quadriceps group strength changes are not enough to fully rehabilitate patellar tracking dysfunctions. The use of EMG biofeedback training to selectively strengthen the vastus medialis obliquus appears to be essential in correcting faulty patellar tracking.

Synchronous regulation of VH and CH allotypes among Ig molecules in multi-heterozygous rabbits suppressed with anti-VH allotype antibody: emergence of IgA from suppression prior to IgG and IgM.

Heterozygous rabbits of genotype a1n81f73g74/a2n82f71g75 were suppressed at birth for the VH region a1 allotype. At 8 weeks of age, quantitative analysis of serum IgG, IgM, and IgA molecules showed that the VHa1 specificity was effectively suppressed in the three classes of Ig and that the suppression was extended to the CH region n81 specificity on mu-chains as well as to the CH region f73 and g74 specificities on alphaf and alphag chains. At 26 weeks of age, analysis of serum IgG and IgM molecules showed that a1 was still suppressed to approximately the same extent in both Ig classes and the suppression was still extended to the CH region n81 specificity. However, at 26 weeks, the percentage of molecules with a1 specificity had doubled among serum and colostral IgA molecules and this increase was extended to the CH region f73 and g74 specificities. Thus, the suppressed allotypes reappeared first among IgA molecules. Our data are consistent with a regulatory mechanism which controls and synchronizes the expression of the VHa and the CH allotypes expressed on the same heavy chain. The order of the re-expression of the suppressed allotypes with respect to Ig class may allow further definition of selective regulatory mechanisms for the synthesis of Ig classes.

Distribution of covalently bound and non-covalently bound secretory component on sbuclasses of rabbit secretory IgA.

The distribution of non-covalently bound secretory component (SC) on the two subclasses, IgA-f and IgA-g of rabbit secretory IgA (sIgA) was determined; the two subclasses were separated from each other by the use of antibody-immunosorbent columns and were subjected to SDS polyacrylamide gel electrophoresis. No SC appeared to be dissociated from the IgA-f molecules from each of 11 different rabbits; the IgA-g molecules, however, did have SC which was dissociated by SDS. Thus, all of the noncovalently bound SC on rabbit sIgA resides on the IgA-g subclass molecules.