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T Ishino

Publications and source records attributed to T Ishino.

At least 19 recordsLinked to original sources
PubMed2001

DNA ligase IV-deficient cells are more resistant to ionizing radiation in the absence of Ku70: Implications for DNA double-strand break repair.

Vertebrate cells have evolved two major pathways for repairing DNA double-strand breaks (DSBs), homologous recombination (HR) and nonhomologous DNA end-joining (NHEJ). To investigate the role of DNA ligase IV (Lig4) in DSB repair, we knocked out the Lig4 gene (LIG4) in the DT40 chicken B-lymphocyte cell line. The LIG4(-/-) cells showed a marked sensitivity to X-rays, bleomycin, and VP-16 and were more x-ray-sensitive in G(1) than late S or G(2)/M, suggesting a critical role of Lig4 in DSB repair by NHEJ. In support of this notion, HR was not impaired in LIG4(-/-) cells. LIG4(-/-) cells were more x-ray-sensitive when compared with KU70(-/-) DT40 cells, particularly at high doses. Strikingly, however, the x-ray sensitivity of KU70(-/-)/LIG4(-/-) double-mutant cells was essentially the same as that of KU70(-/-) cells, showing that Lig4 deficiency has no effect in the absence of Ku. These results indicate that Lig4 is exclusively required for the Ku-dependent NHEJ pathway of DSB repair and that other DNA ligases (I and III) do not substitute for this function. Our data may explain the observed severe phenotype of Lig4-deficient mice as compared with Ku-deficient mice.

Animals↗
PubMed2001

Solution structure of the ribosome recycling factor from Aquifex aeolicus.

The solution structure of ribosome recycling factor (RRF) from hyperthermophilic bacterium, Aquifex aeolicus, was determined by heteronuclear multidimensional NMR spectroscopy. Fifteen structures were calculated using restraints derived from NOE, J-coupling, and T1/T2 anisotropies. The resulting structure has an overall L-shaped conformation with two domains and is similar to that of a tRNA molecule. The domain I (corresponding to the anticodon stem of tRNA) is a rigid three alpha-helix bundle. Being slightly different from usual coiled-coil arrangements, each helix of domain I is not twisted but straight and parallel to the main axis. The domain II (corresponding to the portion with the CCA end of tRNA) is an alpha/beta domain with an alpha-helix and two beta-sheets, that has some flexible regions. The backbone atomic root-mean-square deviation (rmsd) values of both domains were 0.7 A when calculated separately, which is smaller than that of the molecule as a whole (1.4 A). Measurement of 15N-[1H] NOE values show that the residues in the corner of the L-shaped molecule are undergoing fast internal motion. These results indicate that the joint region between two domains contributes to the fluctuation in the orientation of two domains. Thus, it was shown that RRF remains the tRNA mimicry in solution where it functions.

Amino Acid Sequence↗
PubMed2001

PTEN mutation located only outside exons 5, 6, and 7 is an independent predictor of favorable survival in endometrial carcinomas.

Although the prognostic impact of PTEN mutation in endometrial carcinoma is beginning to be analyzed, the prognostic significance of mutated PTEN exons has not ever been described. Sixty-seven endometrial carcinomas were analyzed for PTEN mutations using single-strand conformation polymorphism analysis and DNA sequencing. First, survival rates were compared according to PTEN status and mutated PTEN exons. Subsequently, univariate and multivariate analyses of various favorable prognostic factors for survival were conducted. The associations between PTEN mutation and clinicopathological features were also statistically evaluated. PTEN mutations were detected in 37 of 67 (55%) specimens. Among 47 mutations, frameshifts (57%) and mutations in exon 8 (38%) were most frequent. In univariate analysis, a factor of PTEN mutation only outside exons 5-7 was associated with significantly better survival (P = 0.02), although mutation in any exon of PTEN was not (P = 0.33). Subsequent multivariate analysis revealed that factors of mutation only outside exons 5-7 of PTEN, stage I/II, and G1 were significant and independent prognostic indicators for favorable survival (P = 0.004, 0.004, and 0.0006, respectively). In the subset of advanced-stage disease, mutation only outside exons 5-7 was associated with a trend toward better survival (P = 0.13). No significant correlation was observed between PTEN mutation and estrogen-related clinicopathological features. In conclusion, we find that PTEN mutation located only outside exons 5-7 is a significant and independent positive prognostic indicator for survival. The current observation has prognostic and therapeutic implications for the management of patients with endometrial carcinoma.

Adult↗
PubMed2000

Interaction of ribosome recycling factor and elongation factor EF-G with E. coli ribosomes studied by the surface plasmon resonance technique.

BACKGROUND: Ribosome recycling factor (RRF), in concert with elongation factor EF-G, is required for disassembly of the post-termination complex of a ribosome after the release of polypeptides. How RRF dissociates the complex has long been puzzling. Crystal structures of RRF molecules have been solved recently and shown to mimic a transfer RNA (tRNA) shape, which prompted us to examine whether RRF binds to the ribosome as tRNA does. RESULTS: The formation of ribosome complexes on the surface-coupled RRF and elongation factor EF-G of Escherichia coli was monitored in real time with a BIACORE 2000 instrument based on the surface plasmon resonance technique. RRF interacted with 70S ribosomes as well as 50S and 30S subunits, although it interacted preferentially with 50S subunits, which was clearly seen under high but physiological ionic conditions. This 50S interaction was diminished by a single amino acid substitutions for Arg132 of RRF, which did not appreciably affect the protein folding but nullified the activity in vivo and in vitro. Moreover, a set of antibiotics that inhibited the RRF-50S interaction were also inhibitory to the polysome breakdown activity of RRF in vitro. The BIACORE technique also worked very well in demonstrating the action of the antibiotics thiostrepton and fusidic acid, which are inhibitory to the RRF function by freezing the pre- and post-translocation intermediates catalysed by EF-G. CONCLUSIONS: These results suggest that the preferential interplay of RRF with the 50S subunit may be of biological significance, probably reflecting the mode of RRF action. The BIACORE technique proved useful for real-time monitoring of the interaction between the ribosome and translation factors, as well as for screening of potential inhibitors for ribosome recycling factor.

Amino Acid Substitution↗
PubMed1998

The role of calcium-binding sites in S-modulin function.

S-modulin controls rhodopsin phosphorylation in a calcium-dependent manner, and it has been suggested that it modulates the light sensitivity of the photoreceptor cell. S-modulin binds to the ROS membrane at high Ca2+ concentration, and N-terminal myristoylation is necessary for this property (the calcium-myristoyl switch). S-modulin has four EF-hand motifs, of which two (EF-2 and -3) are functional. Here, we report on the roles of EF-2 and -3 in S-modulin function (calcium binding, membrane association, and inhibition of rhodopsin phosphorylation) by site-directed mutants (E85M and E121M). Surprisingly, E121M, which has a mutation in EF-3, neither binds Ca2+ nor inhibits phosphorylation. In contrast, E85M binds one Ca2+ and has the same membrane affinity as wild-type S-modulin, but has lost the ability to inhibit rhodopsin phosphorylation. It is suggested that the binding of Ca2+ to EF-3 is probably required for EF-2 to be a functional Ca2+-binding site and to induce exposure of the myristoyl group; and that the binding of Ca2+ to EF-2 is important for the interaction with rhodopsin kinase.

Binding Sites↗
PubMed1998

cDNA cloning of mouse prolyl endopeptidase and its involvement in DNA synthesis by Swiss 3T3 cells.

A cDNA for mouse prolyl endopeptidase (PEP) was cloned and its nucleotide sequence determined. The overall amino acid sequence identity between mouse and other mammalian PEPs was about 96%. A specific inhibitor of PEP, N-benzyloxycarbonyl-thioprolyl-thioprolinal- dimethylacetal (ZTTA), inhibited DNA synthesis by Swiss 3T3 cells. Mouse PEP was shown to be localized partly in restricted nuclear regions. These results suggest that PEP participates in mammalian DNA synthesis.

3T3 Cells↗
PubMed1997

Functional expression and characterization of frog photoreceptor-specific calcium-binding proteins.

S-modulin (sensitivity-modulating protein) is a photoreceptor-specific calcium-binding protein which plays an important role in the light adaptation process by controlling rhodopsin phosphorylation in rods. S-modulin and its cone homologue, s26, were expressed at high level (more than 30% of total protein) in Escherichia coli and then purified. They both inhibited rhodopsin phosphorylation in a calcium dependent manner. Myristoylated recombinants of S-modulin and s26 showed calcium-dependent changes in tryptophan emission spectra with half-maxima at about 0.7 microM free calcium concentration. However, the spectral changes are distinctive from each other, suggesting that there is some difference in the structural change between S-modulin and s26.

Adenosine Triphosphate↗
PubMed1997

[Case report: lung abscess caused by Streptococcus agalactiae].

Streptococcus agalactiae is a well-recognized cause of neonatal sepsis and meningitis. In adults, infections by S. agalactiae are rare. We report an adult case of lung abscess and pyogenic spondylitis caused by S. agalactiae. A 51-year-old male was admitted to our hospital because of an abnormal shadow in the chest and lumbago on May 25, 1995. He was diagnosed as lung abscess from the chest roentgenogram and CT scan and the subcutaneous pus was aspirated. The pus culture was only positive for S. agalactiae. He was treated with IPM/CS 1 g/day and CLDM 1.2 g/day and the abscess was drained. MRI showed his lumbago was caused by pyogenic spondylitis. The underlying disease of this case was diabetes mellitus. He recovered from the infections with in about 10 weeks of antibiotic treatment.

Humans↗
PubMed1997

[A case of bacterial meningitis induced by strongyloidiasis].

A 75-year-old female with diabetes mellitus, who was born and lived in West north Kyusyu, was admitted to our hospital, because of unconsciousness and loss of appetite. The physical examination showed neck stiffness and a high fever. The laboratory data showed accentuation of inflammatory reaction and azotemia and positive HTLV-1 antibody. The spinal fluid showed increase of cell count and amount of protein. A stool and sputum smear revealed rhabditis form larvae of the nematode. Antibiotics and ivermectin were administered for the bacterial meningitis and hyperinfection of the strongyloides, respectively. Consequently, meningitis and strongyloidiasis improved. It was considered that the patient was infected with strongyloides from her husband who serve in the army during World-War II, and hyperinfection of strongyloides resulted from the immunosuppressive state of diabetes mellitus. Ivermectin, and anti-strongyloides agent, was effective, and no side effects were seen. However, the therapeutic resistance in this case was associated with the positive HTLV-1 antibody.

Aged↗
PubMed1995

Adenosquamous carcinoma of the pancreas.

A 58-year-old Japanese man was admitted complaining of abdominal pain. An abdominal computed tomography examination demonstrated a tumor in the head of the pancreas and multiple calcifications. A laparotomy was performed and the tumor was removed by Whipple's operation. Histologically, the neoplasm that invaded the duodenal wall and the papilla of Vater was composed of nests of malignant squamous cells with intercellular bridges and showed the formation of keratinized pearls with a small area of concurrently neoplastic glandular and squamous elements. On the basis of these features, the diagnosis of adenosquamous carcinoma of the pancreas was made. The patient died 18 months after the operation. The neoplastic behavior of this rare primary pancreatic carcinoma is similar to that of duct cell carcinoma as well as pure squamous cell carcinoma of the pancreas. As the pancreas can be the target of metastases of squamous carcinomas from other organs it is wise to be aware of this rare entity.

Carcinoma, Adenosquamous↗
PubMed1995

[Yearly changes of isolated organisms from the respiratory tract in Hokusho Central Hospital].

Isolated organisms from the respiratory tract have been studied in our hospital from 1986 to 1993. The total number of samples were 18,345 and samples which showed 10(5) cfu/ml organisms were 8648 in our hospital for 8 years. Enterobacteriacae, Pseudomonas aeruginosa, Haemophilus influenzae, Streptococcus pneumoniae, and glucose nonfermenting gram-negative rods were major isolates in 8 years. Haemophilus influenzae, which used to be the commonest isolate, decreased from 10.9% in 1993 while Enterobacteriacae increased from 8.9% in 1986 to 17.6% in 1993. S. pneumoniae and H. influenzae were major isolates from out-patients consisting of 50%, followed by Enterobacteriacae, P. aeruginosa and MSSA. Enterobacteriacae and P. aeruginosa were major isolates from in-patients, followed by MRSA and beta-Streptococcus. Streptococcus agalactiae, Serratia marcescens and Corynebacterium spp. prevailed especially in the geriatric ward. S. pneumoniae, H. influenzae and M. catarrhalis were major isolates from patients with pneumoconiosis, especially in winter.

Bacteria↗
PubMed1995

[Epidemic of Salmonella enteritidis infection of childhood in the northern area of Nagasaki].

Salmonella Enteritidis infections were a local epidemic in the northern area of Nagasaki, Japan, during August to September in 1992. Out patients (142) visited our hospital because of diarrhea and-or abdominal pain and 96 patients had stool cultures and 51 patients were diagnosed as Salmonella infection. Of the 51 patients it was found that the Salmonella serogroups were 09, 07, 08 and the number of patients were 42, 8, 1, respectively. Phage type 1 was identified in all of the S. Enteritidis infected 38 patients who were examined. About 90% of the patients were under 10 years old. Namely, this Salmonella Enteritidis epidemic in childhood. The peak epidemic period was consistent with the local summer festival and the etiology of infection was thought to be caused by polluted handmade ice cream. S. enteritidis was identified from the ice cream which was also phage type 1. The latent period was 87 hrs.

Child↗
PubMed1995

A rare case of primary pulmonary choriocarcinoma in a male: immunohistochemical detection for human chorionic gonadotropin, epidermal growth factor (EGF) and EGF-receptor.

a rare case of primary choriocarcinoma of the lung in a male is described with immunohistochemistry for human chorionic gonadotropin (hCG), epidermal growth factor (EGF) and EGF-receptor. The extragonadal trophoblastic origin of this pulmonary carcinoma was definitely confirmed by an autopsy examination, and hCG-production and hCG-positive staining of the tumor cells. Furthermore, the tumor cells clearly expressed EGF and its receptor which play an important role in the proliferation and differentiation of normal and neoplastic trophoblasts of the uterus. Our present case suggests that EGF may act in an autocrine manner in the tumor cells of primary pulmonary choriocarcinoma.

Aged↗
PubMed1995

Clinical evaluation of catheter-related fungemia and bacteremia.

Forty-four patients with catheter-related infection admitted to Hokusho Central Hospital between 1985 and 1991 were studied retrospectively. The rate of catheter-related fungemia or bacteremia to all corresponding cases of fungemia and bacteremia increased from 7.7% in 1985 to 28.8% in 1991. The isolated pathogens were Candida parapsilosis (8 strains), Candida tropicalis (6 strains), methicillin-resistant Staphylococcus aureus (MRSA) (6 strains), methicillin-sensitive S. aureus (MSSA) (5 strains) and Streptococcus epidermidis (3 strains). Bacteremia occurred after catheterization of the femoral vein for a mean duration of 37 days. The period was significantly shorter than that after catheterization of the subclavian vein (56 days). The major isolates from the subclavian vein were Candida spp. (14/17, 82.4%), followed by MRSA (1/17, 5.9%) and MSSA (1/17, 5.9%), while isolates from the femoral vein were Candida spp. (6/16, 37.5%), MRSA (5/16, 31.3%) and MSSA (3/16, 20.8%). Catheter removal alone did not improve the clinical condition, particularly in MRSA bacteremia; the combination of antimicrobial therapy and removal of the catheter was necessary for a better prognosis.

Aged↗
PubMed1995

IgA nephropathy associated with hyper IgAnemia, psoriasis or pustulosis and ossification.

This is a report on two cases of IgA nephropathy associated with psoriasis vulgaris, having hyper IgAnemia (above 500 mg/dl) and ossification. Case 1 is a 47-year-old woman with a 7-year history of psoriasis vulgaris, and case 2 is a 57-year-old man with a 17-year history of this disease. IgA was 526 and 1,356 mg/dl, respectively. HLA analysis showed A2, A26 (10), Bw62 (15), Bw46, Cw3, DRw12 (5), and DRw8 in the former, and A2, A11, B13, Bw46, Cw11, DR4, and DRw8 in the latter. Renal biopsy specimens disclosed mild mesangial proliferative glomerulonephritis and moderate mesangial proliferative glomerulonephritis with predominant IgA deposition in mesangial area, respectively. A bone-scintigraphy revealed a high uptake of radioisotopes in the left shoulder, the vertebra, the sacroiliac joint, both sides of the knees and ankles, and the sterno-cost-clavicular area. An X-ray study showed ossification of the posterior longitudinal ligament (OPLL) in the former, and ankylosing spinal hyperostosis (ASH) in the latter. A review of the literature discloses three other case reports of hyper IgAnemia, IgA nephropathy, psoriasis or pustulosis, and ossification. The alertness of dermatologists, orthopedic surgeons, rheumatologists, and general practitioners will be required to attain to a more frequent diagnosis of the above combination.

Female↗
PubMed1994

[Five cases of tsutsugamushi disease].

We experienced 5 cases of tsutusgamushi disease from October to November 1993 at Hokusyo Central Hospital. All patients showed high fever, skin rash and eschar and four patients showed lymph node swelling. All cases were diagnosed serologically by indirect-immunofluorescence technique and treated with minocycline. In a survey of anti-Karp, Kato, Gilliam, Kawasaki, Kuroki antibodies, all patients showed the highest antibody titers against the Kawasaki strain and they were considered Kawasaki type. In Nagasaki Prefecture, the number of patients with tsutsugamushi disease has been increasing since 1982. We carried out immunologic and epidemiologic studies about this disease in Nagasaki Prefecture.

Adult↗