Molecular basis and expression of the LWa/LWb blood group polymorphism

The Landsteiner-Wiener (LW) blood group antigens reside on a 42-kD erythrocyte membrane glycoprotein that has recently been cloned. Here, we found that the molecular basis for the LWa/LWb polymorphism is determined by a single base pair mutation (A308G) that correlates with a Pvu II restriction site and results in a Gln70Arg amino acid substitution. COS-7 cells transfected with LWa or LWb cDNAs reacted with human anti-LWa and anti-LWb sera, respectively, as well as with a murine monoclonal anti-LWab antibody, as shown by flow cytometry analysis. Moreover, a 42-kD protein was immunoprecipitated from the transfected cells with the monoclonal anti-LWab antibody. These findings indicate that LWa and LWb are alleles of the LW blood group locus as defined also by a monoclonal anti-LWab of nonhuman origin. In addition, the LW locus has been assigned to chromosome 19p13.3 by in situ hybridization. Study by Southern blot analysis indicated also that the LW locus is composed of a single gene that was not grossly rearranged in rare LW(a-b-) and Rhnull individuals deficient for LW antigens. In addition, Pvu II restriction fragment-length polymorphism analysis indicated that these variants were all homozygous for a phenotypically silent LWa allele.     

Reverse-sequencing chewing patterns before and after treatment of children with a unilateral posterior crossbite

The aim of this study was to compare the percentage of reverse-sequencing chewing cycles in 22 children [9 boys and 13 girls; mean age +/- SD, 8.6 +/- 1.3 and 8.8 +/- 1.5 years, respectively), with a unilateral right or left posterior crossbite, before and after therapy. The chewing cycles were recorded using a kinesiograph while the subjects masticated a soft and a hard bolus on both the crossbite and non-crossbite side. Chewing data were acquired before and 6 months after orthodontic treatment of the crossbite with an orthodontic functional appliance, the 'Function Generating Bite'. The results showed that, before therapy, the percentage of reverse-sequencing chewing cycles on the crossbite side was significantly higher than that on the normal side (P < 0.001) with both the soft and hard bolus. In addition, the percentage of reverse-sequencing chewing cycles on the crossbite side before therapy was significantly greater than after therapy with both a soft and hard bolus (P < 0.001). No significant differences were found in the percentage of reverse-sequencing chewing cycles on the non-crossbite side, before or after therapy, either with a soft or hard bolus.     

The MG-QOL15 for following the health-related quality of life of patients with myasthenia gravis

The MG-QOL15 is helpful in informing the clinician about the patient's perception of the extent of and dissatisfaction with myasthenia gravis (MG)-related dysfunction. The aims of this study were to determine the usefulness of the MG-QOL15 for following individuals with MG and to guide clinical researchers who plan to use the MG-QOL15. We assessed sensitivity and specificity for detecting clinical change and evaluated test-retest reliability. Sensitivities and specificities of various cut-points of change in scores are presented. Also presented are means and standard deviations of MG-QOL15 scores for all patients and for subgroups of patients. The test-retest reliability coefficient was 98.6%. The MG-QOL15 has an acceptable longitudinal construct validity. We consider this instrument to be most useful for informing the clinician about the patient's perception and tolerance of MG-related dysfunction. More objective measures, such as the MG Composite, should also be used to follow disease severity.