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Biomedical subjects

T Ohyama

Publications and source records attributed to T Ohyama.

At least 199 records · Page 11Linked to original sources
PubMed1993

Cisplatin microcrystals suspended in oil--toxicity in mice.

A new dosage format, cisplatin microcrystals suspended in oil (CDDP-oil), was developed for the treatment of peritoneal carcinomatoses. We studied the acute toxicity of CDDP-oil injected intraperitoneally in mice. The 50% lethal dose was 30.3 mg/kg (27.1-33.7 mg/kg at the 95% confidence level), which was 1.79 times that of a cisplatin aqueous solution (CDDP-sol) of 16.9 mg/kg (16.1-17.8 mg/kg at the 95% confidence level). There were no significant differences in the duration of the toxic effects and the toxic symptoms between these two dosage forms. However, the severity of weight loss in the group given CDDP-oil was less than the group given CDDP-sol.

Animals↗
PubMed1993

Similarity in nucleotide sequence of the gene encoding nontoxic component of botulinum toxin produced by toxigenic Clostridium butyricum strain BL6340 and Clostridium botulinum type E strain Mashike.

The complete nucleotide and deduced amino acid sequence of the nontoxic component of botulinum type E progenitor toxin is determined in recombinant plasmid pU9BUH containing about 6.0 kb HindIII fragment obtained from chromosomal DNA of Clostridium butyricum strain BL6340. The open reading frame (ORF) of this nontoxic component gene is composed of 3,486 nucleotide bases (1,162 amino acid residues). The molecular weight calculated from deduced amino acid residues is estimated 13,6810.1. The present study revealed that 33 nucleotide bases of 3,486 are different in the nontoxic component gene between C. butyricum strain BL6340 and C. botulinum type E strain Mashike. This corresponds to the difference of 17 amino acid residues in these nontoxic component.

Amino Acid Sequence↗
PubMed1993

Study on high-strength plastic teeth. Tooth discoloration.

Conventional plastic teeth (CV teeth) are inferior to porcelain teeth in maintaining an adequate esthetic appearance with wear and discoloration, and thus have a shorter period of durability. Recently, high-strength plastic teeth (HS teeth) have been developed and applied to overcome the wear problems of CV teeth. Since HS teeth made of hard resin are still susceptible to staining with pigments, it has been observed that the esthetics of removable partial dentures made from such plastic teeth are gradually impaired in many patients. To investigate the susceptibility of HS teeth to pigments, we conducted an in vitro study by immersing three types of artificial teeth in three coloring liquids. It was found that the HS teeth tended to be less susceptible to the test pigments than the CV teeth to various degrees. In contrast, they showed markedly stronger susceptibility to the pigments than porcelain teeth. For all three artificial tooth types, daily tooth cleaning with an ultrasonic vibrator had a tendency to reduce the coloration in comparison with their counterparts without ultrasonic cleaning.

Acrylic Resins↗
PubMed1993

Study on the castability of Co-Cr alloy for cast plates. Part 3: Effects of alloy fusion temperature and the heating temperature of the cast ring.

Co-Cr alloy is used more frequently than Ni-Cr alloy as a non-precious alloy for cast plates in Japan. However, since the melting temperature of Co-Cr alloy is very high, about 1300 degrees C, and since it oxidizes easily, a vacuum-pressure casting machine capable of melting this alloy in a reduced atmosphere has recently been developed. Using this machine, the effects of fusion temperature and the heating temperature of the cast ring on the Co-Cr alloy were studied. It was found that in the vacuum-pressure casting method, both the fusion temperature of the Co-Cr alloy and the heating temperature of the cast ring had a significant effect (p < 0.01) on the castability of the Co-Cr alloy.

Chromium Alloys↗
PubMed1993

A possible function of DNA curvature in transcription.

The region preceding the beta-lactamase promoter of Escherichia coli plasmid pUC19 has a DNA curvature (curved DNA or bent DNA). Studies using mutant plasmids showed that the curved DNA structure is required for efficient transcription of the beta-lactamase gene and suggested that the requisite shape is a small part of a right-handed coil. Based on these results, the possible functional significance of DNA curvature in transcription will be discussed.

Base Sequence↗
PubMed1993

Clinical trials with intraperitoneal cisplatin microspheres for malignant ascites--a pilot study.

A new formulation (CDDP-MS), which is composed of lactic acid oligomer microspheres incorporating cisplatin, has been developed in a dosage form for peritoneal carcinomatosis. In this pilot study, CDDP-MS was used clinically for the treatment of malignant ascites induced by cancers of the digestive organs. Thirteen patients with malignant ascites received an i.p. administration of CDDP-MS, of which 12 received 100 mg and one received 200 mg of cisplatin/person to control the ascites. Total platinum levels in ascites and blood plasma were measured periodically. Intraperitoneal CDDP-MS decreased malignant ascites completely in eight patients and partially in four patients, and thus gave a response rate of 92%. The platinum concentration in ascites was maintained at a high level for a week after administration, whereas the concentrations in blood plasma were low. The side effects were well tolerated. Intraperitoneal CDDP-MS exhibits a marked therapeutic benefit with small systemic side effects for the treatment of malignant ascites.

Adenocarcinoma↗
PubMed1992

Alteration of the curved helical structure located in the upstream region of the beta-lactamase promoter of plasmid pUC19 and its effect on transcription.

The region preceding the beta-lactamase promoter of Escherichia coli plasmid pUC19 has a curved DNA (bent DNA) structure. The center of the curvature was revealed to exist around nucleotide position 2580 of the plasmid, which is just beside RNA polymerase binding region. It was indicated that the identified region is curved even at 60 degrees C. The gross geometry of the curvature was altered by inserting synthetic double-stranded oligonucleotides between positions 2585 and 2586. Effect of the alteration on strength of the promoter was not detected in vitro. However, in vivo analyses showed that the promoter strength is apparently dependent, in part, on the gross geometry of the curvature. Insertions of 4 and 16 bp, both of which altered the gross geometry of the curvature greatly, caused considerable reductions of in vivo level of beta-lactamase mRNA. In vivo, overall three-dimensional structure of the region covering the promoter and the curvature seems to play some significant role in transcription of the gene.

Base Sequence↗
PubMed1992

Acute toxicity, percutaneous absorption and effects on hepatic mixed function oxidase activities of 2,4,4'-trichloro-2'-hydroxydiphenyl ether (Irgasan DP300) and its chlorinated derivatives.

Acute toxicity of 2,4,4'-trichloro-2'-hydroxydiphenyl ether (Irgasan DP300) (I) and its three chlorinated derivatives, 2',3,4,4'-tetrachloro-2-hydroxydiphenyl ether (II), 2',4,4',5-tetrachloro-2-hydroxydiphenyl ether (III) and 2',3,4,4',5-pentachloro-2-hydroxydiphenyl ether (IV), in mice were examined by intraperitoneal injection. The LD50 values of Irgasan DP300, II, III and IV were 1,090, 710, 650 and 430 mg/kg, respectively. The percutaneous absorptions of these tritiated compounds were also examined by the application on the backs of mice. The radioactivities in most tissues reached to the maximal levels at 12 h or 18 h after dosing, which corresponded to 11-76% of the maximal levels given by the oral administration (Kanetoshi et al. 1988a). These results show the high percutaneous absorbability of Irgasan DP300 and its chlorinated derivatives. The intraperitoneal administrations of III and IV to rats induced hepatic microsomal aminopyrine N-demethylase and aniline 4-hydroxylase activities similarly to phenobarbital. These chlorinated derivatives also increased cytochrome P-450 content, and the activities of aminopyrine N-demethylase and N-methylaniline N-demethylase in hepatic microsomes from mice. The extents of the increases were similar to those by phenobarbital and 3-methylcholanthrene.

Animals↗
PubMed1992

A silicone prosthesis for covering a large tracheal defect in patients who underwent surgery for locally recurrent aggressive thyroid cancer.

Following the usual sleeve or window resection of the trachea, reconstruction of the trachea can be carried out without difficulty in patients with aggressive thyroid cancer. When the cancer recurs locally in those patients, reoperation often yields a large tracheal defect, for which a commercially available tracheostomy cannula or a silicone-tube does not fit. By using a technique in the maxillofacial prosthetic field, it has become possible to make a new type of prosthesis which is more comfortable and acceptable to the patients with a large tracheal defect. A new type of silicone rubber prosthesis is made individually from the mold of each patient. Several appointments are required for adjustments by the chair side. It must tightly obstruct the tracheostomy stoma so that the patient can easily breathe, speak and take oral fluids. Patients can easily remove and replace this device by themselves and care of the prosthesis is easy. The practical use of this type of prosthesis in three patients is reported herein.

Adenocarcinoma↗
PubMed1992

Ossifying fibroma of the thoracolumbar spine: a case report and review of the literature.

A 43-year-old woman with ossifying fibroma of the thoracolumbar vertebrae was presented with a 6-month history of progressive radiculomyelopathy. The symptoms were successfully treated by laminectomy and partial resection of the lesion. This is the first reported case of ossifying fibroma involving the thoracolumbar spine. The clinical significance and management of this rare lesion are discussed with a review of the literature.

Adult↗
PubMed1992

[A survey of intestinal parasites of the foreign laborers (Indonesians and Filipinos) in Ishikawa Prefecture].

A survey of intestinal parasites was conducted on 198 foreign workers aged 19-27 from Inodonesia and Philippines. They work for a private company in Ishikawa Prefecture as technical trainee. On the base of stool examination, 94 (71%) out of 133 Indonesians and 48 (74%) of 65 Filipinos had intestinal helminths and/or protozoan infections. The prevalence of Ascaris lumbricoides, Trichuris trichura and Hookworm was 4.5, 64.1, 10.6%, respectively. In addition, the positive rate of the cyst of Entamoeba coli, Endolimax nana, Blastocystis hominis and Giardia lumblia was 11.1, 5.6, 4.5 and 2.0%, respectively. No E. histolytica was found; however, counter current immunoelectrophoresis revealed that one out of 112 sera possessed the antibody against the antigen of HK-9 strain of E. histolytica. Sixty-three cases of trichuriasis were treated with mebendazole at a dose of 200 mg/day x 3 consecutive days. Re-examination revealed that 53 (85.5%) of them were cured.

Adult↗
PubMed1992

Escherichia coli is able to grow with negligible sodium ion extrusion activity at alkaline pH.

The Escherichia coli mutant NM81, which is deficient in the nhaA gene for the sodium/proton antiporter, still has a sodium ion extrusion activity because of a second antiporter encoded by nhaB (E. Padan, N. Maisler, D. Taglicht, R. Karpel, and S. Schuldiner, J. Biol. Chem. 264:20297-20302, 1989). By chance, we have found that E. coli pop6810 already contains a mutation affecting the sodium ion circulation, probably in or near nhaB, and that its delta nhaA mutant, designated RS1, has no sodium ion extrusion activity at alkaline pH. The growth of RS1 was inhibited completely by 0.1 M sodium, whereas growth inhibition of NM81 was observed only at sodium concentrations greater than 0.2 M. RS1 grew at a normal rate in an alkaline medium containing a low sodium concentration. Furthermore, RS1 grew with a negligible proton motive force in the alkaline medium containing carbonyl cyanide m-chlorophenylhydrazone. The transport activities for proline and serine were not impaired in RS1, suggesting that these transport systems could be driven by the proton motive force at alkaline pH. These findings led us to conclude that the operation of the sodium/proton antiporter is not essential for growth at alkaline pH but that the antiporter is required for maintaining a low internal sodium concentration when the growth medium contains a high concentration of these ions.

Alkalies↗
PubMed1992

Osmotic adaptation of Escherichia coli with a negligible proton motive force in the presence of carbonyl cyanide m-chlorophenylhydrazone.

It has been reported that Escherichia coli is able to grow in the presence of carbonyl cyanide m-chlorophenylhydrazone (CCCP) when ATP is produced by glycolysis (N. Kinoshita et al., J. Bacteriol. 160:1074-1077, 1984). We investigated the effect of CCCP on the osmotic adaptation of E. coli growing with glucose. When E. coli growing in rich medium containing CCCP was transferred to medium containing sucrose, its growth stopped for a while and then started again. This lag time was negligible in the absence of CCCP. The same results were obtained when the osmolarity was increased by N-methylglucamine-maleic acid. In addition to adapting itself to the hyperosmotic rich medium, E. coli adapted itself to hyperosmolarity in a minimal medium containing CCCP, again with a lag time. Hyperosmotic shock decreased the internal level of potassium ion rather than causing the accumulation of external potassium ion in the presence of CCCP. The internal amount of glutamic acid increased in cells growing in hyperosmotic medium in the presence and absence of CCCP. Large elevations in levels of other amino acids were not observed in the cells adapted to hyperosmolarity. Trehalose was detected only in hyperosmosis-stressed cells in the presence and absence of CCCP. These results suggest that E. coli can adapt to changes in the environmental osmolarity with a negligible accumulation of osmolytes from the external milieu but that the accumulation may promote the adaptation.

Adaptation, Physiological↗
PubMed1992

The complete amino acid sequence of the Clostridium botulinum type D neurotoxin, deduced by nucleotide sequence analysis of the encoding phage d-16 phi genome.

The complete nucleotide sequence of Clostridium botulinum type D strain CB16 neurotoxin was determined and the deduced amino acid sequence is reported here for the first time. The structure and function of botulinum type D neurotoxin is discussed from a molecular biological viewpoint. DNA was extracted from toxin-converting phage d-16 phi of C. botulinum type D strain CB16, and a fragment (about 10 kbp) coding for the neurotoxin was cloned into Escherichia coli using lambda gt11. A 21-mer oligonucleotide which corresponds to Phe7 to Val13 of the partial amino acid sequence near the N-terminus of the type D neurotoxin was synthesized and used as a probe to identify the gene encoding type D neurotoxin. The nucleotide sequence contained a single open reading frame coding for 1,275 amino acids (molecular weight of 146,785) and the deduced amino acid sequence corresponded exactly to the partial amino acid sequences determined by direct microsequencing of the neurotoxin fragments. In the dichain molecule of the neurotoxin, Thr2 and Asn443 formed the N-termini of the light chain (M.W. 50,410) and heavy chain (M.W. 96,394) respectively, and these two chains were linked with a disulfide bond between Cys437 on the light chain and Cys450 on the heavy chain. The nucleotide sequence of the D-CB16 neurotoxin differed from that previously reported for type D neurotoxin by three nucleotides.

Amino Acid Sequence↗
PubMed1992

Persistent trigeminal artery associated with brainstem infarct--case report.

A 47-year-old male presented with a sudden onset of right hemiparesis and numbness of the left face. Magnetic resonance imaging demonstrated a lacunar infarct in the ventral pons. Cerebral angiography demonstrated a persistent trigeminal artery (PTA) anastomosing the left internal carotid artery to the distal basilar artery. Bilateral vertebral arteries and the basilar artery below the PTA junction were extremely hypoplastic. The bilateral posterior communicating arteries were embryonic. The posterior fossa circulation was almost independent from the circle of Willis. The poor vascular supply to the posterior fossa probably caused the brainstem infarct.

Brain Stem↗