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N Noguchi

Publications and source records attributed to N Noguchi.

160 records · Page 9Linked to original sources
PubMed1985

Cardio-respiratory effects of paraquat with and without emetics on Wistar rats.

We investigated the effects of paraquat products both containing and devoid of emetics on the cardio-respiratory functions of Wister rats. Anesthetized rats were administered intravenously 0.46 ml/kg Gramoxone, a commercial product containing 24% paraquat and an emetic. Paraquat equivalence equalled 110 mg/kg body weight. ECG and respiratory curves were recorded with a polygraph. Fifteen seconds after injection, A-V block and bradycardia occurred and the heart stopped beating soon after. Though the heart was severely affected, the respiratory curve differed very little from pre-injection values. Administration of pure, 24% paraquat solution (110 mg/kg body weight) inhibited respiration and almost no change was recorded by the ECG. Administration of Paragreen A, a commercial product containing 24% paraquat with no emetic, produced slight change in the ECG but respiration soon became strained and stopped. In accordance with this data, we propose that the emetic contained in Gramoxone is primarily responsible for the cardiovascular failure.

Animals↗
PubMed1983

Correlation of enzyme-induced cleavage sites on negatively superhelical DNA between prokaryotic topoisomerase I and S1 nuclease.

Negatively superhelical pNS1 DNA with a molecular weight of 2.55 MDa (4 kbp) was found to contain 13 specific, unbasepaired sites that are sensitive to a single-strand-specific S1 nuclease cleavage. The S1-cleavage occurred once at these sites. In the absence of added Mg2+, the topoisomerase I purified from Haemophilus gallinarum formed a complex with the superhelical pNS1 DNA which has a hidden strand cleavage. Extensive proteinase K digestion of the complex led to cleavage of the DNA chain. Then the proteinase K-cleaved product was digested with S1, which can cut the opposite strand at the preexisting strand cleavage to generate unit-length linear DNA. Restriction endonuclease analysis of the linear DNA shows that the topoisomerase-induced cleavage occurred once at ten specific sites on the DNA. The topoisomerase caused mainly single-strand cleavage at these sites, but infrequently also caused double-strand cleavage at the same sites. Of interest is the fact that these sites considerably coincide with the S1-cleavable, unbasepaired sites.

Bacillus subtilis↗
PubMed1983

Isolation of a tetracycline-resistance plasmid excised from a chromosomal DNA sequence in Bacillus subtilis.

When Bacillus subtilis GSY908 (recE4-) (H. C. Spatz and T. A. Trautner, 1971, Mol. Gen. Genet. 113, 174-190) protoplasts were infected with Staphylococcus aureus plasmid pNS1 specifying tetracycline resistance (Tcr) (N. Noguchi et al., 1983, Gene 21, 105-112), which was modified such that it either could not replicate or did not carry a functional Tcr gene, a plasmid with a molecular weight of 3.1 X 10(6) (4.9 kb) was generated in Tcr phenotypes. This plasmid, named Tcr pNS1981, exhibited completely different restriction endonuclease cleavage patterns to pNS1 and showed only negligible sequence homology in hybridization experiments. Southern hybridization experiments revealed that pNS1981 arises by excision of a B. subtilis chromosomal DNA sequence. No sequence corresponding to pNS1 was detectable on the chromosome of pNS1981-maintaining B. subtilis. The production of pNS1981 was also observed in B. subtilis RM125 (r-Mm-Mrec+) (T. Uozumi et al., 1977, Mol. Gen. Genet. 152, 65-69.) with almost the same frequency as B. subtilis GSY908. Since the recipient B. subtilis Marburg 168 derivatives stated above are sensitive to Tc, the results indicate that information essential for Tcr is under negative regulatory control in the integrated state on the chromosome. Restriction endonuclease analysis suggested that pNS1981 is essentially the same as pBC16, formerly found in B. cereus (K. Bernhard, H. Schrempf, and W. Goebel, 1978, J. Bacteriol. 133, 897-903).

Bacillus subtilis↗
PubMed1982

A new antithrombogenic material with long polyethyleneoxide chains.

The PVC-g-MnG polymers were synthesized by photo-induced graft copolymerization of methoxypoly (ethyleneoxide)monomethacrylate (MnG) with various chain lengths (n) of polyethyleneoxide (PEO) (n = 4, 9, 15, 23, 50, 100) as side chains to polyvinylchloride (PVC) with photo-sensitive dithiocarbamate groups. Antithrombogenicity has been evaluated in vitro and in vivo. The in vitro and in vivo results indicated that the adsorption of blood elements to the PVC-g-MnG significantly decreased with the increasing PEO chain length (n). From these findings it is suggested that the volume restriction effect resulted from the formation of long-chain PEO on the surface and which effectively suppresses the adsorption of blood elements and prevents the denaturation of blood elements.

Adsorption↗
PubMedDate not supplied

Construction and propagation of deletion derivatives of staphylococcal tetracycline-resistance plasmid pTP-5 in Bacillus subtilis.

Tetracycline-resistance (TCr) plasmid pTP-5 (4.46 kb) from Staphylococcus aureus was cleaved with HindIII into three fragments: A (2.35 kb), B (1.57 kb) and C (0.54 kb). A deletion plasmid (3.92 kb) lacking HindIII-C fragment was obtained, and was designated pNS1. This plasmid retained the TCr phenotype and the ability to replicate autonomously in Bacillus subtilis. A restriction endonuclease cleavage map of pNS1 was constructed. Attempts to construct smaller plasmids by digesting pNS1 with BAL31 nuclease led to production of a set of deletion derivatives whose molecular sizes range from 3.75 to 2.77 kb. Through analyses of these derivatives, the regions essential for autonomous replication and expression of TCr were deduced.

Bacillus subtilis↗
PubMedDate not supplied

Effects of enalapril on the exercise capacity and neurohumoral factors during exercise in patients with chronic heart failure.

The effects of enalapril on exercise capacity and neurohumoral factors during exercise were evaluated in 10 patients with heart failure. Echocardiograms and exercise testing with expired gas analysis were performed before and after enalapril. Blood samples were obtained before and after exercise. Both ejection fraction and percent fractional shortening increased with enalapril (p < 0.05). The anaerobic threshold and peak VO2 did not change with enalapril. Epinephrine and norepinephrine levels at peak exercise decreased with enalapril (p < 0.1). Plasma renin both at rest and at peak exercise increased with enalapril (p < 0.1). Angiotensin II was lower after enalapril both at rest and at peak exercise (p < 0.1 and p < 0.05, respectively). Aldosterone was lower after enalapril both at rest and at peak exercise (p < 0.05). Atrial natriuretic peptide (ANP) was lower after enalapril both at rest and at peak exercise. There was no significant correlations between peak VO2 and changes in neurohumoral factors before and after enalapril during exercise. In conclusion, neurohumoral changes with enalapril occurred during exercise even if exercise capacity did not improve. Moreover, the improvement of cardiac function at rest and neurohumoral factors with enalapril did not lead to a change of exercise capacity.

Aged↗
PubMedDate not supplied

T-2 toxin-induced apoptosis in hematopoietic tissues of mice.

We examined T-2 toxin-induced lesions in the bone marrow and splenic red pulp as many as 48 hr after oral inoculation with 10 mg/kg body weight of T-2 toxin in female ICR:CD-1 mice. Histopathologically, the bone marrow and splenic red pulp showed a significant hypocellularity. In the bone marrow, the number of myelocytes significantly decreased due to the loss of immature granulocytes, erythroblasts, and lymphocytes. The nuclei of the remaining cells showing pyknosis or karyorrhexis were positively stained by the TdT-mediated dUTP nick end labeling (TUNEL) method, and these TUNEL-positive cells showed ultrastructural characteristics of apoptosis. With agarose gel electrophoresis, DNA ladders were clearly detected in bone marrow samples. The number of TUNEL-positive cells in splenic red pulp increased earlier than it did in the splenic white pulp. Thus, T-2 toxin induced-lesions in the hematopoietic tissues and in the lymphoid tissues were brought about by apoptosis of component cells. We believe that damage to the hematopoietic microenvironment may also play an indirect role in the induction of apoptosis in the bone marrow.

Animals↗
PubMedDate not supplied

Cyclooxygenase-2 expression in hepatocellular carcinoma.

BACKGROUND/AIMS: Cyclooxygenase-2 (Cox-2) is an isoform of cyclooxygenase, which is the key enzyme converting arachidonic acids to prostaglandins. It has been reported that Cox-2 is overexpressed in colon cancer, and that inhibition of this enzyme activity reduces colon cancer development in humans and animals. However, the significance of Cox-2 in human liver cancer is still unclear. To clarify significance of Cox-2 in liver cancer, we immunohistochemically examined expression of this enzyme in cancerous and non-cancerous tissues of hepatocellular carcinoma (HCC). METHODOLOGY: Twenty-nine patients with HCC were examined; 10 patients had well differentiated HCC, 10 had moderately differentiated HCC, and 9 had poorly differentiated HCC. RESULTS: Twenty-eight of 29 (97%) patients with HCC exhibited a positive staining. More intense staining of Cox-2 in cancer tissue rather than non-cancerous tissue was observed in 7 of 10 (70%) patients with well differentiated HCC, in 3 of 10 (30%) with moderately differentiated HCC, and in 3 of 9 (33%) with poorly differentiated HCC, respectively. Rate of higher expression of Cox-2 in cancer tissue rather than in non-cancerous tissue of well differentiated HCC was increased, compared to that of moderately and poorly differentiated HCC (7/10 vs. 6/19, p < 0.05). CONCLUSIONS: The results of the present study showed that Cox-2 is related to HCC whose histology is well differentiated.

Aged↗