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Biomedical subjects

T Miwa

Publications and source records attributed to T Miwa.

At least 307 records · Page 17Linked to original sources
PubMed1985

Promoter analysis of the phosphoenolpyruvate carboxylase gene of Escherichia coli.

In order to find the promoter region of phosphoenolpyruvate carboxylase [EC 4.1.1.31] gene (ppc), in vitro transcription was performed using truncated DNA fragments as templates. Transcription mapping showed three promoters as candidates, but only one of them could be assigned to the promoter of ppc gene, considering the nucleotide sequence of its coding region (Fujita, N., Miwa, T., Ishijima, S., Izui, K. and Katsuki, H. (1984) J. Biochem. 95, 909-916). Nuclease S1 mapping showed that the in vivo and in vitro transcription initiation sites are identical and that the site lies 91 or 92 nucleotides upstream the translation initiation site. No alteration of the transcription initiation site was observed whether the cells were starved for an amino acid or grown on various carbon sources. The sequences of the -10 and -35 regions were fairly in accordance with the consensus sequences hitherto reported. Some features of the sequence around the promoter region were discussed.

Base Sequence↗
PubMed1985

Solitary gastric polyps in the fundic gland area. A histochemical study.

Six solitary gastric polyps in the acid-secreting fundic mucosa were histochemically investigated using the mucin histochemistry, immunoperoxidase method, and silver methods for endocrine cells. Histologically, the polyps were grouped into three types: they largely consisted of either hyperplastic foveolar cells (group 1), normal-appearing fundic gland cells with mild cystic changes (group 2) or hyperplastic fundic gland cells with cystic dilatation (group 3). The presence of parietal cells and mucous neck cells was confirmed in all polyps by the immunoperoxidase method using parietal cell autoantibody and the paradoxical Concanavalin A staining, respectively. Regarding the endocrine component, somatostatin-containing cells, Grimelius-positive argyrophil cells, and Fontana-Masson-positive enterochromaffin cells were scattered in the fundic gland area of the polyps as well as in the surrounding normal-appearing fundic mucosa. Gastrin-containing cells were absent. In one of the group 2 polyps and both group 3 polyps, a varying number of glicentin-containing cells were found among the fundic gland components: In one polyp in group 3, glucagon immunoreactivity was detected in the glicentin-containing cells. These findings suggest that some of the polyps express characteristics of the fetal fundic mucosa, since glicentin and glucagon immunoreactivities in normal human stomach have been detected exclusively in the fetal fundus.

Gastric Fundus↗
PubMed1985

A technique for recording the EMG of electrically stimulated skeletal muscle.

A technique for recording the myoelectric activity of electrically stimulated muscle through its motor nerve without the interference of stimuli artifacts has been developed and tested. The technique consists of a wide band differential amplifier with fine intramuscular wire electrodes. The amplified signal is passed through a Chebyshev low pass filter with eight poles at a frequency of 550 Hz. A stimulus calibration study shows that low frequency stimuli had negligible effect on the EMG when set below three times suprathreshold. A test procedure shows artifact-free EMG during action potential rate stimulation as well as during superimposed high frequency recruitment stimulation.

Action Potentials↗
PubMed1985

7-Hydroxyguanine, a novel antimetabolite from a strain of Streptomyces purpurascens. I. Taxonomy of producing organism, fermentation, isolation and biological activity.

Strain A-347, an actinomycete isolated from a soil sample, was found to produce a new antimetabolite, 7-hydroxyguanine. The aerial mycelium formed spiral spore chains with spiny spore surface. The chemical composition of strain A-347 indicated that it was an actinomycete of cell wall Type I. From its morphological, cultural, physiological characteristics and direct comparison with the type culture, this strain was classified as Streptomyces purpurascens. 7-Hydroxyguanine was purified from the broth filtrate by ion exchange chromatography and crystallized from hot 2 M NH4OH. 7-Hydroxyguanine inhibited the growth of experimental tumors such as L1210 leukemia.

Animals↗
PubMed1985

[Evaluation of ACNU alone and combined with tegafur as additions to radiotherapy of the treatment of malignant gliomas--a cooperative clinical trial].

Controlled, prospective, randomized studies were performed to evaluate the effects of 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3- (2-chloroethyl)-3-nitrosourea hydrochloride (ACNU) and ACNU plus tegafur as additions to radiotherapy for the treatment of malignant gliomas. In the first trial, 105 patients with glioblastoma or anaplastic astrocytoma were randomly divided into two groups after surgery and received radiotherapy (RT, 40 to 60 Gy to the whole brain), or radiotherapy plus concomitant chemotherapy with ACNU (100 mg/m2 on day 1 and 42). Effects of the treatment were compared in 82 evaluable patients from results of CT scans taken before and one month after the completion of radiotherapy. The regression rates more than 50% of the tumor size were observed in 15.0% of patients treated with RT alone and in 47.6% of patients treated with RT plus ACNU. The difference was statistically significant (p less than 0.005). In the second trial, 87 patients were randomly divided into two groups and received RT plus ACNU, or RT plus combined chemotherapy with ACNU and tegafur (400 mg/m2, daily for 8 weeks). Sixty-nine patients were within the valid study group. The regression rates more than 50% of the tumor size were observed in 34.2% of patients treated with RT plus ACNU: and in 41.2% treated with RT, ACNU plus tegafur. No statistical difference was noted in the response rate between the groups. These results indicate that ACNU is an effective agent in conjunction with radiotherapy for patients with malignant gliomas, and that tegafur does not enhance the effectiveness of ACNU.

Adolescent↗
PubMed1985

Measurement and comparison of gastric emptying and esophageal manometry in patients with reflux esophagitis.

Forty-two patients with reflux esophagitis were referred for gastric emptying evaluations. Esophageal manometry was performed on them. Gastric emptying was significantly delayed in patients with reflux esophagitis compared to normal subjects. Lower esophageal sphincter pressure (LESP) showed no significant difference between patients and controls. Acid clearing test was prolonged in patients with reflux esophagitis more than in normal subjects. The subjects were divided into two groups for gastric emptying evaluations; a group with delayed gastric emptying and one with rapid gastric emptying as compared with normal criteria. LESP in 7 cases of rapid gastric emptying among 42 patients (16.6%) was only significantly lower than in normal subjects. The pathogenesis of reflux esophagitis had been previously thought to be a low LESP and/or a prolonged acid clearing. However, we think that a delayed gastric emptying may be one of the pathogenetic characteristics.

Esophagitis, Peptic↗
PubMed1985

Gastric pseudopolyposis: a new clinical manifestation of type A gastritis.

Three cases of type A gastritis associated with multiple polypoid lesions of the body of the stomach are presented. The endoscopic congo-red test showed the red to black color changes of the sprayed congo-red only on the top of the polypoid lesions. The endoscopic methylene-blue test revealed no dye absorption on the antral mucosa or on the top of the polypoid lesions, while the dye was absorbed on the flat mucosa surrounding the top of the polypoid lesions. Histological examinations revealed well-preserved oxyntic glands on the top of the polypoid lesions. The flat mucosa showed marked atrophy or intestinal metaplasia. There have been several reports of experimental models of type A gastritis, where chief and parietal cells decreased in considerable number. These findings and the experimental models suggest that the polypoid lesions resulted from atrophic changes of type A gastritis. The top of the polypoid lesions is the residual oxyntic glands. The lesions, therefore, should be called "gastric pseudopolyposis." The spontaneous disappearance of the polypoid lesions seen in one case is thought to be a result of a further progression of the atrophic gastritis. A pronounced G-cell increase was noted in the antrum and lower body of the stomach. This is considered a secondary phenomenon following the marked reduction of acid secretion.

Aged↗
PubMed1984

Renal handling of sodium chloride and its control in birds.

Avian kidneys show features of both mammalian and non-mammalian kidneys, possessing cortical reptilian-type (RT) and medullary mammalian-type (MT) nephrons, blood supplies from renal arterial and renal portal systems, and a primitive macula densa. To determine how these morphological characteristics contribute to unique renal functions, we examined first a possible functional link between the renal tubules and the preglomerular vasculature and, second, the function of the loop of Henle of the MT nephrons. Infusion of 5% NaCl (2.0 ml/kg/h) into the renal portal system of the pullet Gallus domesticus caused diuresis and natriuresis in the infused side, whereas infusion of the same dose into the systemic circulation showed no effect. Infusion of 10% NaCl at a higher flow rate into either the renal portal or systemic routes caused hypernaturemia and a prolonged antidiuresis, presumably due to a release of arginine vasotocin. Plasma renin activity (PRA) decreased during renal portal infusion of hypertonic saline, suggesting that increases in intratubular or peritubular NaCl levels may suppress PRA. The thick limb of the loop of Henle (TLH) isolated from the MT nephron of the quail Coturnix coturnix revealed a lumen-positive, furosemide-sensitive transepithelial voltage (Vt) that requires the presence of both Na and Cl. Net water flux (Jv) was nearly zero when the TLH was perfused and bathed with isosmotic solution. Net water flux increased only slightly and osmotic water permeability (Lp) was low when the osmotic gradient was imposed. Vasotocin altered neither Vt, Jv, nor Lp. Chloride efflux was higher than Cl influx, and net Cl absorption was comparable to that of the TLH of the mammalian kidney.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Molecular cloning of the phosphoenolpyruvate carboxylase gene, ppc, of Escherichia coli.

The ColE1 hybrid plasmid, pLC20-10, carrying the ppc gene and the argECBH gene cluster of Escherichia coli K-12, was characterized. The ppc gene coding for phosphoenolpyruvate carboxylase (EC 4.1.1.31), was subcloned into the plasmid pBR322 to give the plasmids pS2 and pS3. These plasmids carried a 4.4-kb SalI segment containing the ppc gene, in both orientations. The specific activity of the enzyme was increased approx. 20-fold by these plasmids. Experiments with maxicells harboring pS2 showed that the 90-kDal enzyme subunit was encoded by the plasmid. The location of the ppc gene in pS2 and the direction of transcription of the gene were determined. In DNA-DNA hybridization experiments using pS2 as a probe, significant hybridizations were observed with DNAs from E. coli strains K-12 and W, and from Salmonella typhimurium, but not with those from Chlorella regularis, Anacystis nidulans, Rhodospirillum rubrum, and Pseudomonas AM-1.

Bacteria↗
PubMed1984

The primary structure of phosphoenolpyruvate carboxylase of Escherichia coli. Nucleotide sequence of the ppc gene and deduced amino acid sequence.

The nucleotide sequence of the ppc gene, the structural gene for phosphoenolpyruvate carboxylase [EC 4.1.1.31], of Escherichia coli K-12 was determined. The gene codes for a polypeptide comprising 883 amino acid residues with a calculated molecular weight of 99,061. The amino acid sequence deduced from the nucleotide sequence was entirely consistent with the protein chemical data obtained with the purified enzyme, including the NH2- and COOH-terminal sequences and amino acid composition. The coding region is preceded by two putative ribosome binding sites, and is followed closely by a good representative of rho-independent terminator. The codon usage in the ppc gene suggests a moderate expression of the gene. The secondary structure of the enzyme was predicted from the deduced amino acid sequence.

Amino Acid Sequence↗
PubMed1984

Differential determination of cationic and anionic glutathione S-transferases by enzyme immunoassay.

Specific enzyme immunoassays for cationic and anionic glutathione S-transferases were established using the specific antibodies which were purified by antigen-bound adsorbent column chromatography. The enzyme immunoassay for cationic glutathione S-transferase had high specificity to cationic enzyme, but showed no cross reactivity with anionic one, and vice versa. The recovery of cationic glutathione S-transferase by the enzyme immunoassay was 94.7%, and coefficient of variation for within day and day-to-day precision were 7.8-10.4% and 8.5-12.5%, respectively. The enzyme immunoassay for anionic glutathione S-transferase also had a good recovery and precision. Using these enzyme immunoassays for glutathione S-transferases, sera of various patients were analyzed. Serum cationic glutathione S-transferase was increased in patients with hepatitis and hepatoma, and anionic glutathione S-transferase in serum was increased in patients with liver cirrhosis.

Animals↗