Influence of systemic bone mineral density on atlantoaxial subluxation in patients with rheumatoid arthritis.

Osteopenia and osteoporosis were independent predictive factors for higher atlantoaxial subluxation occurrence in patients with lower body mass index. Our findings suggest that patients with rheumatoid arthritis with osteopenia or osteoporosis, particularly those with lower body mass index (BMI), should be screened regularly to determine the status of their cervical spines. INTRODUCTION: Cervical spine involvement in rheumatoid arthritis (RA) patients may cause serious adverse effects on quality of life and overall health. This study aimed to evaluate the association between atlantodental interval (ADI), atlantoaxial subluxation (AAS), and systemic bone mineral density (BMD) based on BMI variations among established patients with RA. METHODS: The ADI was transformed to the natural log scale to normalize distributions for all analyses. Multivariable linear regression analyses were used to identify independent predictive factors for ADI based on each BMD classification. Multivariate Cox regression analyses were also performed to identify independent predictive factors for the risk of AAS, which were classified by tertile groups of BMI. RESULTS: A total of 1220 patients with RA who had undergone at least one or more cervical radiography and BMD assessments were identified and enrolled. We found that the association between BMD and ADI (ß, -0.029; 95% CI, -0.059 to 0.002; p = 0.070) fell short of achieving statistical significance. However, the ADI showed a 3.6% decrease per 1 BMI increase in the osteoporosis group (ß, -0.036; 95% CI, -0.061 to -0.011; p = 0.004). The osteopenia and osteoporosis groups showed about a 1.5-fold and a 1.8-fold increased risk of AAS occurrence among the first tertile of the BMI group. CONCLUSIONS: Our study showed a possible association between lower BMD and AAS occurrence in patients with RA with lower BMI. Further studies are needed to confirm our findings.

Association of total tooth loss with socio-behavioural health indicators in Korean elderly.

This study examined the association between total tooth loss, and socio-behavioural factors and general health indicators in elderly Koreans using national databases. Cross-sectional data for this study were from the third Korean National Health and Nutrition Examination Survey (KNHANES III), which was conducted among non-institutionalised civilians by the Korean Ministry of Health and Welfare in 2005. KNHANES III used a stratified, multistage probability sampling design on a representative of total South Korean population, according to geographical areas, age and sex groups. Among them, 1091 subjects aged 65 years and above were identified as potential participants in this study. The dependent variable in this study was the self-reported total tooth loss. The independent variables consisted of the following four categories: demographic information, socio-behavioural factors, psychological factors and general health indicators. The data were weighted to adjust for the sampling complexity, and SPSS version 14 for Windows software was used for data analysis. There were significant differences in total tooth loss odds according to the socio-behavioural backgrounds (education and smoking), psychological conditions (perceived oral health) and general health status (diabetes and body mass index as underweight). This suggests that the total tooth loss is associated with the socio-economic status, health-related behaviour and general health. However, more extensive longitudinal data and research will be needed to better explain the relationship between the total tooth loss and these variables.

Pleiotropic effect of a rifampin-resistant mutation in Bacillus subtilis.

Rifampin-resistant (Rifr) mutants were isolated spontaneously from Bacillus subtilis strain 168. A fraction of the mutants did not grow on a minimal medium. A high concentration of one of the L-amino acids (glutamic acid, glutamine, arginine, proline, aspartic acid, or asparagine) was required to restore their growth on the medium. Further analysis of one of the mutants (strain RF 161) suggested that the mutant is unable to use ammonia as a nitrogen source and requires amino acids instead. Activity of glutamate synthase was not detected in the crude extract of the mutant. The Rifr mutation was closely located to cysA and the drug resistance was cotransformed with the property of amino acid requirement at 100% frequency. All revertants to prototrophy tested showed the rifampin-sensitive (Rifs) property. The activity of the DNA-dependent RNA polymerase of the mutant was resistant to rifampin. It is concluded that some alteration of RNA polymerase may cause absence of the activity of an enzyme involved in the nitrogen metabolism.

Salmonella typhimurium LT2 strains which are r- m+ for all three chromosomally located systems of DNA restriction and modification.

We describe the derivation of two strains of Salmonella typhimurium LT2 which are r- m+ for all three of the known chromosomal genes for the restriction and modification of DNA, hsdLT, hsdSA, and hsdSB; the strains were designated LB5000 and LB5010. LB5000 is a smooth derivative sensitive to phage P22; LB5010 is a galE strain sensitive to phage P1.

Ribonucleic acid polymerase mutation affecting glutamate synthase activity in and sporulation of Bacillus subtilis.

Spore formation of 15 rifampin-resistant (Rifr) mutants of Bacillus subtilis strain 168 was examined. As a pleiotropic effect of a Rifr mutation, glutamate synthase activity was lost in these mutants. Twelve of the 15 mutants examined formed as many spores as the parent, but the remaining 3 formed significantly fewer (1%) spores. One of the latter mutants characterized further (RF301) was blocked in its sporulation process at stage 0. Thus, it was concluded that a certain modification of ribonucleic acid polymerase may affect specifically the gene expression of glutamate synthase and also the sporulation process at the initial stage.