Association of activities of daily living and cognitive function with thickness of the upper extremity muscles in children and adults with cerebral palsy.

PURPOSE: We examined the association of activities of daily living (ADL) and cognitive function with the upper extremity muscle thickness and upper extremity range of motion (ROM) and spasticity in children and adults with cerebral palsy (CP). METHODS: The subjects were 20 children and adults with CP. The ADL performed using the upper extremities and cognitive function were assessed using the self-care domain of the Pediatric Evaluation of Disability Inventory (PEDI) and the full-scale intelligence quotient (FSIQ) of the Wechsler Intelligence Scale for Children, fourth edition (WISC-IV), respectively. The WISC-IV was assessed in only seven of 20 subjects able to undergo evaluation. The thickness of the upper extremity muscles was measured using an ultrasound imaging device. Moreover, ROM and spasticity of the upper extremities were assessed using the Modified Ashworth Scale (MAS). Manual manipulation ability was also assessed using the Manual Ability Classification System (MACS). RESULTS: Stepwise regression analysis revealed that the extensor digitorum muscle thickness and MACS level were significant and independent factors of self-care in the PEDI. Partial correlation analysis with MACS level and age as control variables showed that the FSIQ of the WISC-IV was significantly associated with the thickness of the anterior fibers of the deltoid and flexor digitorum superficialis muscles. CONCLUSION: Reduced ADL performed using the upper extremities is associated with decreased extensor digitorum muscle thickness rather than ROM and spasticity of the upper extremities in children and adults with CP.

Comparison of the degree of pes planovalgus and muscle mass of the ankle joint and foot muscles between children with Down syndrome and children with typical development.

We aimed to compare the degree of pes planovalgus and muscle mass of the ankle joint and foot muscles between children with Down syndrome (DS) and children with typical development (TD). We also examined the association of the degree of pes planovalgus with muscle mass of the ankle joint and foot muscles in children with DS and children with TD. The subjects were 24 children with TD (control [CTR] group) and 23 children with DS (DS group). To assess pes planovalgus, the Arch Height Index (AHI) in the standing position was measured. Muscle thickness of the ankle joint and foot muscles was measured using an ultrasound imaging device. The AHI and thickness of the soleus and tibialis posterior muscles were significantly lower in the DS group than those in the CTR group. The thickness of the flexor digitorum longus muscle was significantly greater in the DS group than that in the CTR group. Stepwise regression analysis revealed that the thickness of the flexor digitorum longus muscle was a significant and independent factor of the AHI in children comprising the CTR and DS groups. The thickness of the flexor digitorum longus muscle increased with decreasing AHI. The results of this study suggest that the AHI and muscle mass of the soleus and tibialis posterior muscles decrease, while muscle mass of the flexor digitorum longus muscle increases in children with DS. The results also indicate that decreased AHI is associated with increased muscle mass of the flexor digitorum longus muscle in children.

Magnesium Suppresses Defects in the Formation of 70S Ribosomes as Well as in Sporulation Caused by Lack of Several Individual Ribosomal Proteins.

Individually, the ribosomal proteins L1, L23, L36, and S6 are not essential for cell proliferation of Bacillus subtilis, but the absence of any one of these ribosomal proteins causes a defect in the formation of the 70S ribosomes and a reduced growth rate. In mutant strains individually lacking these ribosomal proteins, the cellular Mg2+ content was significantly reduced. The deletion of YhdP, an exporter of Mg2+, and overexpression of MgtE, the main importer of Mg2+, increased the cellular Mg2+ content and restored the formation of 70S ribosomes in these mutants. The increase in the cellular Mg2+ content improved the growth rate and the cellular translational activity of the ΔrplA (L1) and the ΔrplW (L23) mutants but did not restore those of the ΔrpmJ (L36) and the ΔrpsF (S6) mutants. The lack of L1 caused a decrease in the production of Spo0A, the master regulator of sporulation, resulting in a decreased sporulation frequency. However, deletion of yhdP and overexpression of mgtE increased the production of Spo0A and partially restored the sporulation frequency in the ΔrplA (L1) mutant. These results indicate that Mg2+ can partly complement the function of several ribosomal proteins, probably by stabilizing the conformation of the ribosome.IMPORTANCE We previously reported that an increase in cellular Mg2+ content can suppress defects in 70S ribosome formation and growth rate caused by the absence of ribosomal protein L34. In the present study, we demonstrated that, even in mutants lacking individual ribosomal proteins other than L34 (L1, L23, L36, and S6), an increase in the cellular Mg2+ content could restore 70S ribosome formation. Moreover, the defect in sporulation caused by the absence of L1 was also suppressed by an increase in the cellular Mg2+ content. These findings indicate that at least part of the function of these ribosomal proteins can be complemented by Mg2+, which is essential for all living cells.

Single mutations introduced in the essential ribosomal proteins L3 and S10 cause a sporulation defect in Bacillus subtilis.

We introduced single mutations into the rplC and rpsJ genes, which encode the essential ribosomal proteins L3 (RplC) and S10 (RpsJ), respectively, and are located in the S10 gene cluster of the gram-positive, endospore-forming bacterium Bacillus subtilis, and examined whether these mutations affected their growth rate, sporulation, competence development and 70S ribosome formation. Mutant cells harboring the G52D mutation in the L3 ribosomal protein, which is located at the peptidyl transferase center of 50S, accumulated 30S subunit at 45°C, probably due to a defect in 50S formation, and exhibited a reduction in the sporulation frequency at high temperature. On the other hand, mutant cells harboring the H56R mutation in the S10 protein, which is located near the aminoacyl-tRNA site of 30S, showed severe growth defect and deficiency in spore formation, and also exhibited significant delay in competence development.