Isolation of UV-sensitive mutants of mouse L5178Y cells by a cell suspension spotting method

We have isolated 56 UV-sensitive mutant clones from a mouse L51 T/t line of L5178Y cells by a cell suspension spotting method. Five mutants have also been isolated from L51 T/t and L5178Y cells by the method reported by Thompson and coworkers (22). We divided the mutants into two groups, highly sensitive and moderately sensitive mutants, according to their sensitivity to UV irradiation. Fifty-eight mutants were highly sensitive and three were moderately sensitive to UV. The reconstruction experiments indicate that more than 90% of highly sensitive mutants were recovered by the cell suspension spotting method. Frequencies of recovered mutants highly sensitive to UV increased with increasing dose of mutagens. Recovered mutant frequency reached 10^–2 after treatment with 1.5 g/ml ofN-methyl-N-nitro-N-nitrosoguanidine (MNNG) (survival 0.2%). Eight UV-sensitive mutants were divided into four complementation groups. These mutants were 2–6 times more sensitive to UV than parental L51 T/t cells in terms of D₃₇ (dose required to reduce survival to 37%). Four representative UV-sensitive mutants which are classified into different complementation groups were examined for their sensitivity to killing by UV, 4-nitroquinoline-1-oxide (4NQO), mitomycin C (MMC), X-rays, and MNNG. All four classes of mutants were found to be cross-sensitive to UV, 4NQO, and MMC, but not sensitive to X-rays and MNNG.     

A gamma-lactone form nafuredin, nafuredin-gamma, also inhibits helminth complex I

Nafuredin, a delta-lactone antibiotic, is a fungal metabolite showing selective helminth NADH-fumarate reductase inhibition, and whose target had been revealed as complex I. We found that nafuredin is easily converted to nafuredin-gamma by weak alkaline treatment. The structure of nafuredin-gamma was elucidated as a gamma-lactone form of nafuredin with keto-enol tautomerism. Nafuredin-gamma shows similar complex I inhibitory activity as nafuredin, and it also possesses anthelmintic activity in vivo.     

Right thoracic curvature in the normal spine

Background  

Trunk asymmetry and vertebral rotation, at times observed in the normal spine, resemble the characteristics of adolescent idiopathic scoliosis (AIS). Right thoracic curvature has also been reported in the normal spine. If it is determined that the features of right thoracic side curvature in the normal spine are the same as those observed in AIS, these findings might provide a basis for elucidating the etiology of this condition. For this reason, we investigated right thoracic curvature in the normal spine.     

Additional effects of FDG-PET to thin-section CT for the differential diagnosis of lung nodules: a Japanese multicenter clinical study

Objective  

This study was a controlled multicenter clinical study on patients with peripheral lung nodules to verify the improvement in the diagnostic ability of FDG-PET when used in combination with thin-section CT (TS-CT).     

Additional value of FDG-PET to contrast enhanced-computed tomography (CT) for the diagnosis of mediastinal lymph node metastasis in non-small cell lung cancer: a Japanese multicenter clinical study

Objective  

This study was a controlled multicenter clinical study to verify the diagnostic effects of additional FDG-PET to contrast-enhanced CT for mediastinal lymph node metastasis in patients with operable non-small cell lung cancer (NSCLC).     

Relationship between activity of daily living and motor function in the community-dwelling elderly after hip fracture

AIM: To clarify the relationship between ADL and motor functions in 44 community-dwelling elderly patients with hip fracture. METHODS: The questionnaire comprised items on BADL, IADL, ability to walk, and certification for long-term care. The assessment of motor functions included grip strength, knee extension strength, 10 m walking time, TUG, FRT, and Romberg rate and shift length of the center of gravity measured by a stabilometer. Based on these tests, relationships between the motor functions and ADL were evaluated in elderly patients after hip fracture. RESULTS: Significant correlations were found between BADL and grip strength, knee extension strength, and FRT. As for IADL, significant correlations were found with grip strength, knee extension strength, 10-m walking speed, TUG, FRT, and MMSE items. Similarly, regarding ability to walk and the certification of long-term care, significant correlations were shown with grip strength, knee extension strength, 10 m walking speed, and MMSE items. CONCLUSION: The relationships between ADL and motor functions were confirmed in community-dwelling elderly patients with hip fracture. The parameters related to muscle strength and balance ability that were assessed in this study are those that can be improved through constant training after discharge from hospital. The validity of these parameters as the indices for future intervention studies to assess the maintenance and improvement of ADL after discharge and prognosis was indicated.     

Successful joint arthroplasty after treatment of destructive MRSA arthritis of the knee using antibiotic-loaded hydroxyapatite blocks: a case report

Methicillin-resistant Staphylococcus aureus (MRSA) septic arthritis is frequently associated with a poor clinical outcome. Joint reconstruction may be worth attempting in patients with a history of persistent MRSA infection. Here we report an unusual case of MRSA septic arthritis of the knee joint that was treated successfully by joint replacement after initial placement of antibiotic-loaded hydroxyapatite (HA) blocks.     

Mutation spectrum in UVB-exposed skin epidermis of a mildly-affected Xpg-deficient mouse

A C-terminal 183 amino acid-truncated mutation of the mouse Xpg gene (XpgDeltaex15) gives rise to a partial deficiency in nucleotide excision repair in homozygously affected cells. We studied the effect of this mutation on UVB-induced mutagenesis in mouse skin, using transgenic mice harboring lambda-phage-based bacterial lacZ genes as a mutational reporter. UVB increased the lacZ mutant frequency in the epidermis moderately in the homozygous mutant mice, but significantly higher than in the wild-type or the heterozygous mice, whereas background mutant frequencies were not appreciably different among the three mouse genotypes. Ninety-eight lacZ mutant sequences isolated from the UVB-exposed epidermis of the XpgDeltaex15-homozygous mice were analyzed and compared with mutant sequences from the wild-type mice. The spectra of the mutations in the two mouse genotypes were not significantly different, and they were highly UV-specific. There were frequent C --> T transitions at dipyrimidine sites and several CC --> TT tandem mutations, although the UV-specific mutations occurred more frequently at CpG sites in the mutant mice. The distribution of the mutations observed in the lacZ transgene and the preferred sequence context of the UV-specific C --> T mutations (5'-TC-3' > 5'-CC-3' > 5'-CT-3') in the Xpg-mutant mice were similar to those found in the wild-type mice. Despite these similarities, we detected a previously unrecognized type of the UV-induced mutation only in the Xpg mutant (6/98 in the mutation spectrum of the mutant vs. 0/76 in the wild-type; P = 0.035), which is characterized by multiple base substitutions or frameshifts within a three-nucleotide sequence containing a dipyrimidine. We propose that this putative new class of mutation, which we refer to as a "triplet mutation", is characteristic of UV-induced mutation in an excision-repair-deficient background.