Biomedical subjects

Y Nishimoto

Publications and source records attributed to Y Nishimoto.

At least 73 records · Page 4Linked to original sources

PubMed1993

Cytogenetic abnormalities of hematopoietic tissue in retired workers of the Ohkunojima poison gas factory.

A high incidence of cancer of the respiratory tract has been reported among former workers in a poison gas manufacturing plant which operated on Ohkunojima from 1927 to 1945. This report provides evidence of a high incidence of chromosome abnormality and sister chromatid exchange (SCE) rate among the former workers, as well as cytogenetic changes in two patients among the former workers with chronic myelocytic leukemia (CML). A chromosome study of seven former workers with chronic bronchitis revealed a stable type of aberration, the average abnormality being 10.9 +/- 4.4 percent, which is equivalent to those of atomic bomb survivors exposed at 1.2 km from the hypocenter. The SCE rate observed in 16 former workers ranged from 4.9 +/- 2.1 to 17.8 +/- 3.9, which was significantly higher than in the control group (p < 0.03). One of the CML patients showed an extremely high percentage of missing Y chromosomes along with t(9;22) translocation which is a specific chromosome aberration for the disease. Furthermore, the patient had almost a 3 times higher SCE rate compared to the control group and a high incidence of chromosome abnormality (12.1%) of the peripheral lymphocytes. These results suggest that the development of leukemia in this patient was strongly related to poison gas exposure.

Aged↗

PubMed1993

[Risk factors and therapeutic methods for sternal wound infection following cardiac surgery].

In a study of 1040 patients undergoing cardiac surgery at The Osaka Medical College Hospital from 1984 through 1991, we analyzed the correlation between a variety of preoperative and operative parameters and the risk of postoperative sternal wound infection, as well as the efficacy of various therapeutic method for this condition. Sternal infection or mediastinitis developed after cardiac surgery in 31 patients (3.0%). As the risk factors for wound infections, age, diabetes mellitus, reexploration, duration of cardiopulmonary bypass and use of bilateral internal thoracic artery grafting were listed. Application of pectoral muscle flaps significantly led to shorten a duration between diagnosis of infection and hospital discharge, and increased survival rate, than the other treating methods such as debridement or irrigation. We conclude that bilateral internal thoracic artery grafts should not be used in the cases with diabetes, and closure with pectoral muscle flaps is effective for sternal infection and mediastinitis.

Coronary Artery Bypass↗

PubMed1992

Effect of Nocardia rubra cell-wall skeleton on cancer prevention in humans.

The retired workers at the chemical weapons plant in Japan are regarded as a high-risk group for cancers. Under the Cancer Preventive Program, Nocardia rubra cell-wall skeleton (N-CWS) was administered to 80 workers directly involved in the production of sulfur mustard and 66 workers engaged in work related to sulfur mustard production. Untreated workers whose age, sex, duties and duration of work at this factory were individually matched to the N-CWS-treated workers were used as controls. During a 4.5-year observation period, development of cancers was found in 7 treated workers and 17 untreated controls. After elimination of the influence of the difference in smoking level, the incidence of subjects who developed cancers was compared statistically between the N-CWS-treated workers and the untreated controls and a significant suppression of development of cancers was noted in the N-CWS-treated workers. Thus, it was concluded that the administration of N-CWS could prevent cancer development in humans.

Aged↗

PubMed1992

[Coronary artery bypass utilizing vein grafts: why didn't we use an arterial graft?].

Internal thoracic artery (ITA) grafts for coronary artery bypass grafting (CABG) are superior to SVG in the long-term patency and survival. In spite of our effort to utilize ITA whenever possible, we still have some cases which have to receive only vein grafts. Among the consecutive 201 patients undergoing CABG in the past three years, 32 patients (16%) received only vein grafts. We compared these patients (SVG group) with those who received ITA grafts (ITA group). The SVG group consisted of all emergency cases and many cases with single and double vessel disease. In the SVG group, perioperative use of IABP was more frequent and operative mortality was higher, although the number of grafts was fewer (2.66 vs 3.61) and aortic cross clamping time was shorter in this group. Main reasons for selecting only vein grafts were emergency surgery, inadvertent injury of ITA, inadequate ITA free flow etc. Technical refinement in the preparation of ITA is important to make possible wider application of arterial grafts for CABG.

Aged↗

PubMed1991

Inactivation of DNA polymerase beta by in vitro phosphorylation with protein kinase C.

The Mr = 38,300 polypeptide of the purified recombinant rat DNA polymerase beta served as an excellent substrate for protein kinase C (PKC) in vitro but not for the catalytic subunit of cAMP-dependent protein kinase. The phosphorylation by PKC resulted in inactivation of DNA polymerase beta activity, and recovery was achieved by dephosphorylation with alkaline phosphatase. Since the phosphorylated DNA polymerase beta was retained with use of a single-stranded DNA-cellulose column, inactivation might occur at a site different from that for the DNA binding. Amino acid sequence analysis of the phosphopeptides revealed that the phosphorylated sites were 2 serine residues at positions 44 and 55 from the NH2 terminus, either or both of which might be involved in the catalytic activity of DNA polymerase beta. Thus, the inactivation of the DNA repair enzyme, DNA polymerase beta, by PKC may be an important process in the modification of DNA metabolism in the nucleus through signal transduction processes.

Alkaline Phosphatase↗

PubMed1991

Aspartic acid residues at positions 190 and 192 of rat DNA polymerase beta are involved in primer binding.

The sequence Gly-Asp-Met-Asp, spanning positions 189-192 of rat DNA polymerase beta, is similar to the sequence motif Gly-Asp-Thr-Asp that is highly conserved in a number of replicative DNA polymerases from eukaryotic cells, viruses, and phages. The role of this sequence in the catalytic function of rat DNA polymerase beta was investigated by individually changing each amino acid in this region by site-directed mutagenesis. The mutant enzymes DE190 and DE192, in which aspartic acid residues at positions 190 and 192, respectively, were replaced by glutamic acid, showed about 0.1% activity of the wild-type enzyme. On the other hand, the replacement of Gly-189 by alanine or Met-191 by isoleucine or threonine only slightly affected the enzyme activity. A gel mobility shift assay showed that DNA complexes with enzyme DE190 and especially with DE192 were less stable than the corresponding complex with the wild-type enzyme. Kinetic analysis with these mutant enzymes indicate that their Km's for primer DNA were about 10-fold higher than that of the wild type, while Km's for deoxyribonucleoside triphosphate were not changed. Since neither DE190 nor DE192 had any significant alteration in secondary structure, our results suggest that both Asp-190 and Asp-192 are located in the active site and are involved in the interaction of DNA polymerase beta with primer.

Amino Acid Sequence↗

PubMed1991

Gallium-67 citrate scintigraphy in the pre-operative evaluation of soft tissue tumors of the extremities.

We conducted a study of 90 patients with soft tissue tumor in their arms or legs, in order to determine the usefulness of scintigraphy with gallium-67 citrate as a diagnostic means. All patients had adequate scan images, and tumor tissues had been histologically confirmed by surgical resection. The subjects consisted of 19 patients with malignant tumors, 55 patients with benign tumors, and 16 patients with other disorders in which soft tissue tumor-like lesions occurred. When the activity of the tumor was more than the activity of the normal region of the contralateral extremity, it was estimated to be positive. The positive rate was found in 78% (15/19) of patients with malignant tumors, in 25% (14/55) of patients with benign tumors and in 31% (5/16) of patients with other disorders. Classified by diseases, high positive rates were observed in liposarcoma, leiomyosarcoma, malignant lymphoma, neurinoma, extra-abdominal desmoid and sarcoidosis. Out of 7 patients in which the activity of the tumor was equal to, or higher than that of the liver, 6 patients had malignant tumors and one patient was diagnosed as having an abscess. It seemed possible to distinguish between liposarcoma and lipoma by means of a gallium-67 scan. Furthermore, the gallium-67 scan was useful in detecting lesions of sarcoidosis as well as in evaluating the response to treatment.

Adolescent↗

PubMed1991

Organization of mouse DNA polymerase beta gene silencer elements and identification of the silencer-binding factor(s).

Different portions of the 5'-upstream region of the mouse DNA polymerase beta gene were combined with bacterial chloramphenicol acetyltransferase (CAT) gene of the CAT vector. Transfection of these recombinant plasmids into mouse NIH/3T3 cells has revealed that each of the previously identified two negatively acting regions (silencers I and II) of this gene consists of multiple sub-domains. The distal silencer (silencer I) at around -1.5 kb consists of four sub-domains (-1852 to -1667, -1663 to -1616, -1564 to -1525 and -1355 to -1257). The promoter-proximal silencer (silencer II) at around -0.5 kb consists of two functional domains (-681 to -523 and -490 to -447) separated by a neutral region of 33 base pairs. Silencer II functioned efficiently when silencer I was deleted. Conversely, the distal silencer I functioned efficiently when silencer II was deleted. Thus, these silencers functioned redundantly to each other in NIH/3T3 cells. Nucleotide sequence analysis revealed no extensive sequence similarity between these two silencers. Significant sequence similarity is present between a distal portion of silencer II and the c-myc gene silencer, and also between a proximal portion of silencer II and the mouse F9 cell-specific silencer. A protein factor(s) that specifically bound to the silencer elements was detected in nuclear extracts of NIH/3T3 cells and mouse liver in which DNA polymerase beta was expressed at a rather low level. The same binding factor(s) can bind to both silencer I and II regions, although its affinity for silencer II is much higher than that for silencer I.

Animals↗

PubMed1991

Isolation and characterization of new allosamidins.

Three of new allosamidins, termed glucoallosamidins A (5), B (6) and methyl-N-demethyl-allosamidin (4), were isolated as yeast chitinase inhibitors from the mycelium of Streptomyces sp. SA-684.

Acetylglucosamine↗

PubMed1991

[A case of sinus arrest during a surgical operation].

A 75-year old obese female was scheduled for mastectomy due to breast tumor. At the preoperative examinations, she had premature atrial contraction on electrocardiogram. But she had no clinical signs or symptoms regarding sick sinus syndrome. She was evaluated as ASA risk II and arranged for neuroleptanesthesia. During the operation, she developed severe bradycardia and asystole lasting for 7 seconds, which was not effectively controlled by atropine sulfate. Then cardiac rhythm resumed spontaneously and she recovered with no neurological deficits. On the postoperative examination of 24 hr-Holter ECG, she showed bradycardia and sinus arrest and she was diagnosed to have sick sinus syndrome.

Aged↗

PubMed1990

Site-directed mutagenesis of recombinant rat DNA polymerase beta: involvement of arginine-183 in primer recognition.

By site-directed mutagenesis using synthetic oligonucleotides, amino acid residues 181Phe-Arg-Arg183 of recombinant rat DNA polymerase beta were replaced by other amino acids to clarify the roles of these residues in the DNA synthesizing reaction. Replacement of Phe-181 by alanine reduced the enzyme activity only 30%. Replacement of Arg-182 by alanine and glutamine resulted in reduction of the activity by about 67% and 95%, respectively. The Arg-182----Gln replacement increased the binding strength to single-stranded DNA but did not significantly change the Km's for the primer and dTTP, suggesting that Arg-182 is involved in modulation of binding to the template rather than to the primer or deoxyribonucleoside triphosphate. Replacement of Arg-183 by Gln resulted in reduction of the activity by about 95%, and this change, although causing little change in binding strength to single-stranded DNA, resulted in a 3-4-fold increase in the Km's for the primer and deoxyribonucleoside triphosphate. A more dramatic change was observed when Arg-183 was replaced by Ala, which resulted in a 99.98% reduction of enzyme activity. Although the Km for deoxyribonucleoside triphosphate of this mutant enzyme was hardly changed, that for the primer increased 159-fold. Therefore, it is concluded that Arg-183 occupies an important part of the primer recognition site of DNA polymerase beta.

Amino Acid Sequence↗

PubMed1990

Coprecipitation of 3'----5' exonuclease and DNA polymerase gamma with anti-DNA polymerase gamma antibody.

Highly purified preparations of chick embryo DNA polymerase gamma contained 3'----5' exonuclease activity which might be responsible for the exonucleolytic proofreading during DNA synthesis [Kunkel, T.A. & Soni, A. (1988) J. Biol. Chem. 262, 4450-4459]. A rabbit antibody produced against highly purified chick DNA polymerase gamma precipitated 3'----5' exonuclease activity to the same extent as DNA polymerase gamma activity. Furthermore, the antibody neutralized the two enzyme activities to an equal extent. However, the exonuclease activity was more resistant than DNA polymerase gamma activity to thermal treatment at 50 degrees C, although both activities were partially protected with polynucleotides. The results obtained suggest that these two enzymes are associated as a single enzyme complex or that the two activities reside in a single molecule, and the active site of DNA polymerase gamma and 3'----5' exonuclease are, although not identical, closely correlated.

Animals↗

PubMed1990

[Echocardiography in patients with malignant metastatic neoplasms of the heart and great vessels].

Two-dimensional echocardiography was used to study malignant metastatic neoplasms of the heart and great vessels in 20 patients, 13 males and seven females, whose ages ranged from 15 to 72 years. Five patients had lung cancer; two each had breast cancer, malignant melanoma, hepatoma and one each had gastric cancer, urinary bladder cancer, adrenocortical carcinoma, malignant lymphoma, angiosarcoma, fibrosarcoma, leiomyosarcoma; and two had cancers with unknown primaries. Tumor invasion was demonstrated echocardiographically in the left atrium in one each with breast cancer, fibrosarcoma and gastric cancer; in the right atrium in two with hepatomas; in the right atrium and right ventricle in one patient with adrenocortical carcinoma; in the left ventricle in one with lung cancer; and in the pulmonary artery in one with malignant melanoma. Massive pericardial effusion was observed in 11 of 20 patients; two with pericardial tumors including malignant lymphoma and lung cancer. We conjectured that metastatic tumors in the right cardiac cavities came through the inferior vena cava, and other tumors in the left atrium, left ventricle and pericardium developed from direct extension of the primary lesions. There was an 80% mortality of the patients during the observation period, and the average survival period after the diagnosis of cardiac metastases was 5.5 months. However, one patient was still living after two years of radiation therapy and chemotherapy. Echocardiography proved a useful, non-invasive means for the detection and follow-up observation of metastatic cardiac tumors.

Adolescent↗

PubMed1990

[Continuous intra-arterial infusion chemotherapy for malignant bone and soft tissue tumors in pelvis and trunk areas].

We evaluated the effectiveness of intra-arterial infusion chemotherapy for 21 cases of malignant bone and soft tissue tumors in the pelvis and trunk areas. Eight cases are alive for one or two years without operation. In all cases, pain was decreased and quality of life improved. We concluded that intra-arterial infusion chemotherapy is one of the useful treatments for malignant bone and soft tissue tumors in the pelvis and trunk areas.

Adolescent↗

PubMed1989

[Limb-saving surgery of malignant bone tumors using massive bone grafts].

The artificial materials in limb-saving surgery pose problems such as the age of patient, tolerance and stability. Thus, massive bone grafting should be reconsidered. In our clinic, out of 78 patients having malignant bone tumors, 29 received limb-saving surgery, and 10 of these cases received massive bone grafting using autografts and/or frozen allografts between 1968 and 1987. There were 7 cases with osteosarcoma, 1 case with mesenchymal chondrosarcoma, 1 case with leiomyosarcoma and 1 case with malignant fibrous histiocytoma. There were 5 males and 5 females ranging in age from 11 years to 44 years, and averaging 21 years. According to Enneking's staging system, these were all II-B cases. The median follow-up period was 71 mos, ranging from 13 to 239 mos. According to the modified Amago evaluation method, 80% of these cases had an excellent prognosis, one had a recurrence, but in all cases good bone union and stability were achieved without immunological reaction. Therefore we conclude that massive bone grafts in cases of malignant bone tumor surgery is a very beneficial method.

Adolescent↗

PubMed1989

[Systolic time intervals in mitral valve prolapse syndrome].

Systolic time intervals (STI) were measured in 135 patients with mitral valve prolapse syndrome (MVP). These patients were categorized as Group II (no or trivial mitral regurgitation) and Group III (moderate or severe regurgitation). The controls consisted of 120 normal subjects (Group I). The Group II patients tended to have increased ETc and shortened PEP. The Group III patients tended to have prolonged Q-I and decreased QIIc and ETc, reflecting mitral regurgitation. It was suggested that autonomic nervous system, especially sympathetic nerve, may play a role in changes of STI of the Group II patients.

Adolescent↗

PubMed1989

[Preoperative continuous intra-arterial infusion chemotherapy as part of a local regional treatment of osteosarcoma of the extremities].

Preoperative continuous intra-arterial chemotherapy combined with surgery in the treatment of osteosarcoma has been since 1968 in our clinic. Sixty-three cases with osteosarcoma of the extremities were evaluated in this study. Eighteen of these cases underwent limb salvage procedures. There were three intralesional, eleven marginal and four wide excision cases. From the standpoint of local failures, there were only two recurrent cases. One occurred after a marginal excision and the other after an intralesional excision. The 5-year cumulative survival rate for limb salvage cases was 56.0%, as compared with 40.6% of the amputation cases. Therefore we conclude that preoperative continuous intra-arterial infusion chemotherapy is a very effective method as a local regional therapy for osteosarcoma of the extremities.

Adolescent↗

PubMed1988

Expression of active rat DNA polymerase beta in Escherichia coli.

A recombinant plasmid for expression of rat DNA polymerase beta was constructed in a plasmid/phage chimeric vector, pUC118, by an oligonucleotide-directed mutagenesis technique. The insert contained a 1005 bp coding sequence for the whole rat DNA polymerase beta. The recombinant plasmid was designed to use the regulatory sequence of Escherichia coli lac operon and the initiation ATG codon for beta-galactosidase as those for DNA polymerase beta. The recombinant clone, JMp beta 5, obtained by transfection of E. coli JM109 with the plasmid, produced high levels of DNA polymerase activity and a 40-kDa polypeptide that were not detected in JM109 cell extract. Inducing this recombinant E. coli with isopropyl beta-thiogalactopyranoside (IPTG) yielded amounts of 40-kDa polypeptide as high as 19.3% of total protein. Another recombinant clone, JMp beta 2-1, which was constructed by an oligonucleotide-directed mutagenesis to use the second ATG codon for the initiation codon, thus deleting the first 17 amino acid residues from the amino terminus, produced neither high DNA polymerase activity nor the 40-kDa polypeptide. The evidence suggests that this amino-terminal structure is important for stability of this enzyme in E. coli. The DNA polymerase was purified to homogeneity from the IPTG-induced JMp beta 5 cells by fewer steps than the procedure for purification of DNA polymerase beta from animal cells. The properties of this enzyme in activity, chromatographic behavior, size, antigenicity, and also lack of associated nuclease activity were indistinguishable from those of DNA polymerase beta purified from rat cells, indicating the identity of the overproduced DNA polymerase in the JMp beta 5 and the rat DNA polymerase beta.

Amino Acid Sequence↗