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Biomedical subjects

T Ohyama

Publications and source records attributed to T Ohyama.

At least 181 records · Page 10Linked to original sources
PubMed1995

[Endoscopic injection of methotrexate bound to activated carbon particles in the treatment of gastric cancer].

A new dosage formulation (MTX-CH), composed of fine activated carbon particles absorbing methotrexate (MTX), distributes concentrated MTX for long periods of time to the regional lymph nodes as well as to the injection site, in animal experiments. MTX-CH would enhance the therapeutic effects not only on the primary lesion but also on the lymphatic metastasis. As clinical trials, (A) in five patients with early gastric cancer, MTX-CH at 50 to 200 mg/person of MTX was injected endoscopically in and around the primary lesion before operation. Surgically removed specimens showed that three out of the 5 primary lesions had disappeared or were necrotic, and the remaining two lesions had shrunk. (B) Three patients with contraindication to surgery received the endoscopic injection of MTX-CH. The MTX-CH injected at 250 to 1,500 mg/person into and around the primary lesion of relatively early gastric cancer resulted in the complete disappearance of the primary lesions for 14 to 24 months up to the present time without enlargement of the lymph nodes. It was thought that local injection of MTX-CH will be effective therapy, especially for gastric cancer with potential lymphatic metastasis in patients with contraindications to surgery.

Animals↗
PubMed1995

[Trial of a treatment for lymph node metastases in patients with breast cancer using aclarubicin bound to activated carbon particles].

A new dosage formulation (ACR-CH), composed of aclarubicin (ACR) bound to fine activated carbon particles, was developed for the treatment of lymph node metastases in patients with breast cancer. In a mice experimental model, ACR-CH had superior therapeutic effects on lymph node metastases compared to the same dose of ACR aqueous solution. In clinical trials, patients with breast cancer received a local injection of 10 mg/person of ACR in the form of ACR-CH or ACR aqueous solution just before mastectomy. In the regional lymph nodes removed by the operation, the ACR concentration of 40.7 micrograms/g in patients given ACR-CH was higher than the 25.1 micrograms/g in patients given ACR aqueous solution, whereas in blood plasma the concentration was higher in patients given ACR aqueous solution than in those given ACR-CH.

Aclarubicin↗
PubMed1995

[Development of 5-fluorouracil incorporated in microspheres for peritoneal carcinomatosis--animal experiments].

A new dosage formulation (5-FU-MS), composed of 5-fluorouracil (5-FU) incorporated in polyglactin microspheres, was studied by animal experiments, which revealed the following results. Intraperitoneal 5-FU-MS delivered greater concentrations of 5-FU for longer periods selectively to the intraperitoneal tissues, whereas it delivered a lower concentration to the blood plasma, than 5-FU solution did in rats. In mice, the 50% lethal dose value of intraperitoneal 5-FU-MS was 535 mg/kg. The toxicity of 5-FU-MS was less than 1/2 that of intraperitoneal 5-FU solution, of which the 50% lethal dose value was 242 mg/kg. Intraperitoneal 5-FU-MS at 200 mg of 5-FU/kg improved the survival curve of mice with peritoneal carcinomatosis better than the identical dose of 5-FU solution.

Animals↗
PubMed1995

[Chronic inflammatory demyelinating polyneuropathy associated with chronic liver disease due to type B and type C hepatitis virus].

A patient with chronic inflammatory demyelinating polyneuropathy (CIDP) associated with type B and type C hepatitis virus infection is reported. A 54-year-old female who had a blood transfusion at the age of 31 years was diagnosed as a carrier of hepatitis B virus at the age of 43. Liver dysfunction was first noted in 1987 and gradually grew worse year by year. Beginning in early June 1992, the patients general fatigue became worse, her serum GOT and GPT levels became elevated, and she complained of a tingling sensation in her arms and legs. Neurological examination revealed moderate sensory disturbance of the glove-and-stocking type in all of her extremities. Deep tendon reflexes were all diminished. Hepatitis C antibody was detected in the serum at this time. On June 12, 1993, progression of her sensory disturbance was found to be associated with generalized muscle weakness. Cerebrospinal fluid studies showed increased protein without pleocytosis. Motor nerve conduction studies revealed marked prolongation of terminal latencies, reduction of conduction velocities, and abnormal temporal dispersion of the motor potentials. No sensory potentials could be evoked at any of the sites stimulated. Sural nerve biopsy showed segmental demyelination and severe loss of large myelinated fibers as well as some onion bulb formation. A diagnosis of CIDP was made. Treatment with corticosteroids was started, but there was little improvement in neurological function. The liver dysfunction progressed further and ultimately the patient died of hepatic failure. An autopsy demonstrated liver cirrhosis, but no malignant tumors were evident.(ABSTRACT TRUNCATED AT 250 WORDS)

Chronic Disease↗
PubMed1995

Effects of an upstream DNA curvature on the strength of HSV thymidine kinase promoter.

The effect of an upstream DNA curvature on the strength of the herpes simplex virus thymidine kinase (TK) promoter was investigated by employing luciferase assay. A set of double-stranded oligonucleotides, each with an unique DNA configuration, were synthesized and substituted into an upstream region of the promoter. It was revealed from the assay that both plane and space curves exerted a negative influence upon the strength of the promoter.

Base Sequence↗
PubMed1994

Molecular construction of Clostridium botulinum type C progenitor toxin and its gene organization.

The 16S progenitor toxin of Clostridium botulinum type C is made up by conjugation of a neurotoxin with nontoxic components designated as nontoxic-nonHA and hemagglutinin (HA). The HA was found to be composed of subcomponents having 53, 33, 22-23, and 17 kDa molecular masses. Since we previously determined the whole nucleotide sequences of the genes for neurotoxin, nontoxic-nonHA, and HA-33, the cloning and nucleotide sequencing of the genes for the remaining HA subcomponents were performed. Two open reading frames coding for 16.7 kDa (HA-17) and 70.6 kDa proteins were identified. The N-terminal amino acid sequences of HA-53 and HA-22-23 indicated that the 70.6 kDa protein is split into 53 and the 22-23 kDa proteins after translation and that the 22-23 kDa protein consists of at least four proteins showing slightly different molecular weights.

Amino Acid Sequence↗
PubMed1994

Selective delivery of a greater amount of methotrexate to regional lymph nodes using a new dosage formulation, methotrexate adsorbed on activated carbon particles, in rats.

A new dosage formulation (MTX-CH) comprising methotrexate (MTX) adsorbed onto a suspension of activated carbon particles was developed for the treatment of lymph node metastases. In vitro studies showed that activated carbon particles adsorbed a great amount of MTX. Subcutaneous injection of MTX-CH into the left hind foot pad of rats distributed a greater amount of MTX selectively to the regional lymph nodes (the left popliteal node and the para-aortic nodes) for a longer period of time than similar administration of MTX aqueous solution with a smaller amount of MTX distributed to the rest of the whole body.

Adsorption↗
PubMed1994

Escherichia coli cad operon functions as a supplier of carbon dioxide.

We examined the gene expression of the Escherichia coli cad operon, which consisted of the genes cadB and cadA (lysine decarboxylase), using cells possessing cadB-lacZ fusion gene. The cad operon was expressed when O2 was limited, and the expression was optimal at pH 6.3. The beta-galactosidase activity was lowered by the addition of sodium carbonate to the medium. The expression of the cad operon was reduced in cells containing the plasmid-encoding ornithine decarboxylase, which produced carbon dioxide, indicating that the gene expression of the cad operon was regulated by carbon dioxide (or its derivatives). It is known that the Krebs cycle is a major pathway for producing carbon dioxide, and that its activity is repressed when O2 is limited. Thus, our present results suggested that the physiological role of the cad operon is to supply carbon dioxide when its internal level is lowered under O2-limiting conditions at a low pH.

Amino Acid Transport Systems↗
PubMed1994

Physiological role of the chaA gene in sodium and calcium circulations at a high pH in Escherichia coli.

Ohyama et al. previously isolated Escherichia coli mutant RS1, which had a negligible activity for sodium ion extrusion at alkaline pH (T. Ohyama, R. Imaizumi, K. Igarashi, and H. Kobayashi, J. Bacteriol. 174:7743-7749, 1992). Our present study showed that the mutation of RS1 was compensated for by a cloned chaA gene. It has been proposed that sodium ion extrusion by ChaA is prevented under physiological conditions (D. M. Ivey, A. A. Guffanti, J. Zemsky, E. Pinner, R. Karpel, E. Padan, S. Schuldiner, and T. A. Krulwich, J. Biol. Chem. 268:11296-11303, 1993). In order to clarify the physiological role of chaA in sodium ion circulation at alkaline pH, we constructed a delta chaA mutant. The resultant mutant, TO112, deficient in both nhaA and chaA, was unable to grow at pH 8.5 in medium containing 0.1 M sodium chloride and had negligible sodium ion extrusion activity. However, TO112 grew at pH 7.0 in medium containing 0.4 M sodium chloride. Sodium ions were extruded from TO112 cells at neutral pH. The extrusion activity at pH 7.5 was greatly reduced by the deletion of nhaB. These data demonstrate that the activity of nhaB is low at high pH and that ChaA extrudes sodium ions at alkaline pH. The uptake of calcium ions by everted membrane vesicles prepared from the delta chaA mutant TO110 was 60% of the activity observed in the vesicles of the wild-type strain at pH 8.5, but the activity at neutral pH was not reduced by the deletion of chaA. Therefore, it was also suggested that ChaA plays a role in calcium ion circulation at alkaline pH.

Antiporters↗
PubMed1994

[Densitometric quantitation of platelet activating factor and other phospholipids in human saliva using enzyme reaction on a silica plate].

A sensitive quantitative analysis by thin layer chromatography was developed for the determination of platelet activating factor (PAF) and other phospholipids in human saliva. The saliva sample (0.6 ml) was pretreated by diatomite column extraction with chloroform-methanol (95:5, v/v). The extract (20 microliters) was spotted on a TLC plate. The mobile phase was chloroform-methanol-water (65:35:7, v/v). The development proceeded until the mobile phase front reached 8 cm from the spotted point, this process usually required 30 min. After development, phospholipase C and alkaline phosphatase solutions were sprayed on the TLC plate at 45 degrees C to hydrolyze phospholipids. By spraying a mixture of ammonium molybdate and Malachite Green, the produced phosphate was changed to molybdophosphate-Malachite Green aggregate, which gave a blue green spot. The colored spots were scanned at 620 nm by chromatoscanner. A linear relationship was obtained between peak area and PAF concentration in the range from 2 to 100 pmol/spot with a relative standard deviation of 2% (n = 7). By this procedure, lysophosphatidylcholine, phosphatidylcholine and phosphatidylethanolamine in human saliva were also determined sensitively. PAF levels in the range from 40 to 300 ng/ml were found in normal human salivas. Although differences in the total amounts of phospholipids in saliva were found for each healthy volunteer and sampling time, the composition of phospholipids was proved to be virtually constant.

Densitometry↗
PubMed1994

Hyperplastic polyps following treatment of acute gastric ulcers.

Although hyperplastic polyps are the most common polyps of the stomach, the etiology of these polyps is not completely understood. We report a 61-year-old woman who developed gastric hyperplastic polyps following acute gastric lesions. She was admitted for endoscopic injection sclerotherapy of esophageal varices. After the end of sclerotherapy, acute gastric lesions developed. For treatment of the lesions, omeprazole was used for 8 weeks followed by famotidine for 8 weeks. At the end of the treatment, she developed multiple gastric hyperplastic polyps, suggesting that acute gastric lesions and/or treatment of the gastric lesions are related to the development of hyperplastic polyps in the stomach.

Esophageal and Gastric Varices↗
PubMed1994

Emerging symptoms of growing skull fracture after secondary trauma in an adult--case report.

A 20-year-old female presented with dysphasia and slight hemiparesis following a head trauma, who had a non-treated growing skull fracture which had remained asymptomatic for about 18 years, despite an encephalocele in the left parietal region. Neuroimaging demonstrated secondary brain damage and herniated brain resulting in gliosis. Electroencephalography revealed epileptic discharge in the affected region. Dural repair and cranioplasty resolved her neurological deficits. Early corrective surgery should be performed for growing skull fracture to prevent secondary brain damage.

Adult↗
PubMed1994

Study on the castability of Co-Cr alloy for cast plates. Part 4. Effects of sectional area, number of sprues and alloy components on castability.

Co-Cr alloy is used more frequently than Ni-Cr alloy as a nonprecious alloy for cast plates in Japan. Titanium with good biocompatibility has often been contained in the composition of this Co-Cr alloy. However, since the melting temperature of Co-Cr alloy is very high, about 1300 degrees C, and it oxidizes easily, a vacuum-pressure casting machine capable of melting this alloy in a reduced atmosphere has recently been developed. In this study, using the vacuum-pressure casting machine, the possible effects of sectional area and the number of sprues attached to the cast plate wax pattern, as well as the alloy components, on the castability of three kinds of Co-Cr alloy containing titanium were examined. It was found that all of these parameters had significant effects on Co-Cr alloy castability.

Chromium Alloys↗
PubMed1994

[The prevention of peritoneal dissemination of gastric cancer with intraperitoneal activated carbon particles absorbing mitomycin C].

A new drug dosage form comprising activated carbon particles absorbing mitomycin C (MMC-CH) has the advantage of being retained in the peritoneal cavity and distributes a larger amount of mitomycin C for a long time. Some 113 patients with gastric cancer and serosal infiltration were randomly assigned intraperitoneal treatment with MMC-CH and no anti-cancer drugs. There were significant differences in survival rate between the patients who have no visible peritoneal dissemination with MMC-CH and without. Thus, intraoperative intraperitoneal treatment with MMC-CH improves survival after gastrectomy for gastric cancer and seems effective against peritoneal recurrence.

Absorption↗
PubMed1993

Roles of histamine and diamine oxidase in mucosa of rat small intestine after ischemia-reperfusion.

To examine the roles of histamine and diamine oxidase in the intestine after ischemia-reperfusion, we measured histamine content, diamine oxidase activity, and ornithine decarboxylase activity in rat intestinal mucosa 6 hr following various periods of ischemia. In addition, mortality rates of rats after various periods of ischemia were observed. The superior mesenteric artery was occluded for 15, 30, or 60 min. Ornithine decarboxylase activity increased in the 15-, 30-, and 60-min ischemic groups compared to the sham-operated control group. In the prolonged ischemic group (60-min ischemia), both histamine concentration and diamine oxidase activity in the mucosa decreased, contributing to an increase in circulating histamine. In the 60-min ischemic group, the mortality rate of rats was 25%, which was significantly larger than the control groups. Pretreatment with aminoguanidine, which suppressed diamine oxidase activity, increased the mortality rate. These results indicate that histamine released from the intestinal mucosa has a harmful effect on rats, and diamine oxidase activity plays an important role when the small intestine is subjected to prolonged period of ischemia.

Amine Oxidase (Copper-Containing)↗