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Biomedical subjects

K Arima

Publications and source records attributed to K Arima.

At least 217 records · Page 12Linked to original sources
PubMed1984

[A clinical survey of bacteria isolated from urine specimens of patients with various urological disease].

We have clinically surveyed the distribution and disk sensitivity of bacterial strains obtained from urine of patients with various urological disease at our department during three (1975-1977) and four (1980-1983) years. Escherichia coli was the most frequently isolated (29.4%) from the outpatients, followed by Staphylococcus epidermidis (17.5%), Pseudomonas cepacia (11.2%) and Serratia marcescens (11.2%). Pseudomonas cepacia was the most frequently isolated (28.0%) from the inpatients, followed by Staphylococcus epidermidis (16.3%) and Serratia marcescens (15.9%). Pseudomonas cepacia which has been increasing was first isolated in 1977 and Serratia marcescens in 1976. They have become the main bacteria causing infections in our hospital. Pseudomonas cepacia was frequently isolated after postoperative prophylactic chemotherapy and Serratia marcescens in the late period of admission. The majority of Pseudomonas cepacia was resistant to all agents except chloramphenicol and doxycycline. Serratia marcescens was also resistant except to gentamicin and doxycycline. In Escherichia coli species, resistant strains increased gradually but they have good sensitivity to gentamicin, dibekacin, colistin and doxycycline. Staphylococcus epidermidis isolated from outpatients had good sensitivity to all agents but increased in incidence of resistant strains isolated from inpatients.

Anti-Bacterial Agents↗
PubMed1983

The nucleotide sequence of the yeast PHO5 gene: a putative precursor of repressible acid phosphatase contains a signal peptide.

The nucleotide sequence of the PHO5 gene of the yeast, Saccharomyces cerevisiae, which encodes repressible acid phosphatase (APase) was determined. Comparison of N-terminal amino acid sequence deduced from the nucleotide sequence with that of the purified repressible APase revealed the existence of a putative signal peptide in the precursor protein. The signal peptide was shown to contain 17 amino acid residues and its structural features were quite similar to those of higher eukaryotic and prokaryotic signal peptides. The nucleotide sequence of 5' and 3' noncoding flanking regions of the PHO5 gene are also discussed.

Acid Phosphatase↗
PubMed1983

Inhibition of p-hydroxybenzoate hydroxylase by anions: possible existence of two anion-binding sites in the site for reduced nicotinamide adenine dinucleotide phosphate.

Certain anions were found to inhibit p-hydroxybenzoate hydroxylase from Pseudomonas desmolytica. The inhibition was of competitive or mixed type with respect to NADPH (apparent Ki = 4-30 mM). Among the anions, monovalent anions such as halogen ions and azide inhibited ionization of the phenolic hydroxyl group of the substrate (p-hydroxybenzoate) on binding with the enzyme . substrate complex of p-hydroxybenzoate hydroxylase, without dissociating the substrate from the enzyme. On the other hand, multivalent anions (anions of polybasic acids), such as inorganic phosphate, borate, and sulfate, did not inhibit the ionization. Halogen ions induced remarkable spectral changes in the FAD moiety of the enzyme on binding, while the change due to inorganic phosphate was only slight. Chloride inhibited the binding of NADH with the enzyme as well as that of NADPH, whereas borate inhibited the binding of only NADPH. These results indicate that the monovalent and multivalent anions probably bind to the sites in the enzyme which interact, respectively, with the pyrophosphate and 2'-phosphate moieties of NADPH. The results provide strong support for the catalytic mechanism in which the phenolate anion of p-hydroxybenzoate participates in the process of substrate hydroxylation by C (4a) peroxyflavin. The results also suggest that repeated ionization/neutralization of the phenolic hydroxyl group of the substrate may occur during one cycle of the catalytic turnover.

4-Hydroxybenzoate-3-Monooxygenase↗
PubMed1983

[A clinical survey on 24 cases of primary ureteral tumors].

A clinical survey was performed on 24 cases of primary ureteral tumors treated in our University Hospital between Jan. 1972 and Dec. 1981. The incidence of primary ureteral tumors was 0.17% among the outpatients in our urologic clinic. The patients ranged from 41 to 84 years old in age (average age: 65 years), and the male to female ratio was 3 to 1. The left ureter and the lower third of the ureter were involved more frequently. The most frequent initial symptom was macrohematuria seen in 19 cases (79%), followed by loin pain seen in 6 cases (25%). A cytologic study of the voided urine or ureteral urine was carried out in 18 cases and positive results were obtained in 9 cases (50%). Cystoscopic examination revealed a tumor protruding through the ureteral orifice in 16.7% (4 of 24 cases), followed by bulging orifice in 8.3% (2 of 24 cases). Excretory pyelography showed ureteral filling defects in 41.7% (10 of 24 cases). Retrograde pyelography showed ureteral filling defects in 100% (10 of 10 cases). CT showed a mass region in 44.4% (4 of 9 cases). A total of 14 patients underwent nephroureterectomy with partial or total cystectomy (66.7%). The overall 5-year-survival rate was 56.5% and could be directly associated with grade and stage of tumors.

Adult↗
PubMed1983

[Studies of dietary influence on urinary oxalate in calcium oxalate stone formers].

In order to examine the effect of diet on the urinary excretion of oxalate, a spinach loading and milk loading experiment was performed in normal subjects and patients with single calcium oxalate stones and recurrent calcium oxalate stones after a rat experiment. When spinach (100 g, total oxalate 642.57 mg, insoluble oxalate 282.21 mg, taken oxalate 444.57 mg) was given with a low calcium diet to the patients, the increase of urinary oxalate was more prominent in those with recurrent stones; the mean urinary oxalate increased from 39.84 to 84.18 mg/day (P less than 0.01) in the group with recurrent stones, from 36.95 to 55.12 mg/day (P less than 0.05) in the group with single stones and from 33.99 to 42.78 mg/day in the control group. These increases in oxalate excretion could be ameliorated by the concurrent oral administration of milk (calcium 343 mg). Moreover, diurnal variation in oxalate excretion was observed. It was more evident under spinach load in the group with recurrent stones than in the control group. Urinary oxalate increased promptly, reaching peak levels between 4 and 6 hours after loading in the group with recurrent stones and single stones, and between 2 and 4 hours in the control group. The influence of the spinach load disappeared within 24 hours.

Adult↗
PubMed1982

Photo-oxidation of a histidyl residue of milk-clotting acid protease, Mucor rennin.

Mucor rennin, a milk-clotting acid protease produced by a fungus Mucor pusillus, was inactivated by photo-oxidation mediated by methylene blue according to first order kinetics. The pH profile of the inactivation rate showed that a dissociating group with a pK value of 7.6 was involved in the inactivation. Addition of pepstatin A, an inhibitor specific for acid proteases, caused a marked alkaline shift of the pK value. One of two histidyl residues in the enzyme was destroyed by the photo-oxidation, with complete loss of the enzyme activity. Analysis of inhibitor binding activity and chemical modification with diazoacetyl-DL-norleucine suggested that the photo-oxidized enzyme still retained its original conformation. These results indicated that one histidyl residue in addition to the two essential carboxyl groups is involved in the catalytic function of Mucor rennin.

Chymosin↗
PubMed1982

Proton magnetic resonance spectroscopy of an essential histidyl residue in a milk-clotting acid protease, Mucor rennin.

The location and state of an essential histidyl residue in a milk-clotting acid proteases, Mucor rennin, were investigated by NMR spectroscopy. Assignment of the C2H resonance peak of the essential histidyl residue was possible by comparison of the NMR spectrum of the native enzyme with that of the photo-oxidized enzyme. The pH titration curve for the chemical shift of the C2H proton showed two inflections, a major one with pKa = 7.4 and a minor one with pKa = 3.5 at 30 degrees C. The major inflection, corresponding to an intrinsic protonation of the imidazole ring, shifted toward the alkaline side upon addition of acetyl pepstatin, an inhibitor specific for the acid protease. Modification of an essential carboxyl group in the enzyme with diazoacetyl-DL-norleucine caused disappearance of the minor inflection as well as an acidic shift of the major pKa value. Perturbation effects on the C2H resonance of the lanthanide metals, Pr3+, Eu3+, and Gd3+, suggested their selective binding to a carboxyl group and location of the bound metal atom close to the essential histidyl residue. All data suggested that the essential histidyl residue of Mucor rennin is located close to one of the two essential carboxyl groups in the catalytic site of the enzyme.

Animals↗
PubMed1981

Purification and properties of a copper-containing nitrite reductase from a denitrifying bacterium, Alcaligenes faecalis strain S-6.

A copper-containing nitrite reductase was purified and crystallized from a potent denitrifying bacterium, Alcaligenes faecalis strain S-6. The enzyme was composed of 4 subunits with a molecular weight of about 30,000, each containing 1 atom of Cu2+. Nitric oxide was identified as a main reduction product from nitrite in the enzyme-catalyzed reaction. The enzyme activity was inhibited strongly by KCN but only slightly by sulfhydryl reagents such as p-chloromercuribenzoate and N-ethylmaleimide.

Alcaligenes↗
PubMed1981

A blue protein as an inactivating factor for nitrite reductase from Alcaligenes faecalis strain S-6.

A blue protein with a molecule weight of 12,000 containing 1 atom of type I Cu2+ was purified and crystallized from a denitrifying bacterium, Alcaligenes faecalis strain S-6, as an inactivating factor for copper-containing nitrite reductase of the same organism. Inactivation of the enzyme occurred when the enzyme was incubated aerobically with a catalytic amount of the blue protein in the presence of reducing agents such as cysteine and ascorbate. The blue protein acts as a direct electron donor for the enzyme to catalyze the reduction of nitrite, but in the absence of nitrite, the enzyme-reduced blue protein system reacts with oxygen to produce H2O2. A suicide inactivation mechanism of the enzyme due to this H2O2 production is proposed.

Alcaligenes↗
PubMed1981

Purification of prorennin and production of its antibody.

Prorennin, i.e. the zymogen of rennin, was extracted from fresh calf stomach and purified by ammonium sulfate precipitation, ion exchange chromatography and gel filtration. The purified prorennin was homogeneous as judged by SDS-polyacrylamide gel electrophoresis. A specific antibody to the purified prorennin was induced in rabbits. In a double diffusion test and on immunoelectrophoresis the antibody gave a single precipitin line when run against crude and pure zymogen preparations. In the double diffusion test, the antibody also reacted with a purified rennin but not with gastric proteases (pepsin and pepsinogen) or other proteases (trypsin and Mucor rennin). When the antibody was tested against prorennin and rennin in the double diffusion test, a spur was formed at the junction of the precipitin lines against prorennin and rennin. This result confirms that the two proteins share an antigenically common structure in their molecules and that the activation segment of prorennin contains at least one antigenic determinant.

Animals↗
PubMed1980

An essential arginine residue at the substrate-binding site of p-hydroxybenzoate hydroxylase.

p-Hydroxybenzoate hydroxylase (EC 1.14.13.2) was rapidly inactivated by treatment with phenylglyoxal, by a process obeying pseudo-first order kinetics. The reaction with the reagent was also examined by amino acid analyses, radioactivity measurements, and spectrophotometric analyses. Results of these analyses were consistent with each other, which shows that the inactivation was due to modification of argiine residue(s). Addition of saturating amounts of p-hydroxybenzoate (or benzoate) during the treatment resulted in marked protection of the enzyme from the inactivation as well as a significant decrease in modification of arginine residues, while phenol showed no effect. Modification in the absence of p-hydroxybenzoate caused a spectral change in the flavin moiety of the enzyme similar to that due to the enzyme.substrate complex formation, and losses in both the overall activity and the substrate-binding ability accompanied the spectral change. On the other hand, such spectral change was not observed and the substrate-binding ability was retained even after the overall activity had decreased to a great extent when p-hydroxybenzoate as added during the modification treatment. These results suggest that phenylglyoxal (an analogue of the substrate) was incorporatd into the substrate-binding site and that an arginine residue is involved in the site, having an interaction with the carboxylate anion of the substrate.

4-Hydroxybenzoate-3-Monooxygenase↗
PubMed1980

L-Alloisocitrate dehydrogenase and oxalosuccinate decarboxylase from a Pseudomonas sp. utilizing L-alloisocitrate.

Two novel enzymes, NAD+-linked L-alloisocitrate (erythro-Ls-isocitrate) dehydrogenase and oxalosuccinate decarboxylase, were found and purified from a strain of Pseudomonas isolated as an L-alloisocitrate utilizing bacterium. The former enzyme catalyzes a reversible oxidation-reduction between L-alloisocitrate and oxalosuccinate which favors oxalosuccinate reduction. The latter enzyme catalyzes rapid decarboxylation of oxalosuccinate to alpha-ketoglutarate and CO2. Both enzymes require no metals for their activities. Complete oxidative decarboxylation of L-alloisocitrate to alpha-ketoglutarate occurs as a result of the sequential reactions catalyzed by these two enzymes. L-Alloisocitrate induces both enzymes in the growing pseudomonad.

Alcohol Oxidoreductases↗
PubMed1979

Multiple fusion of protoplasts in Saccharomyces yeasts.

Fusion of protoplasts prepared from haploid strains of Saccharomyces yeasts having identical mating type was induced with the aid of polyethylene glycol. Stable fusion products were isolated by complementation of the auxotrophic markers. Of 64 isolates derived by protoplast fusion between two different haploid strains having alpha mating type, 35 fusion products were estimated from their cell volumes to be diploid, 13 to be triploid and 16 to be tetraploid. The isolates showing tetraploid cell size were thought to have resulted from fusion of three protoplasts of one strain and one protoplast of the other (three-to-one fusion) or from two-to-two fusion. In protoplast fusion of three different haploid strains having alpha mating type, all four possible phenotypes of fusion product were recovered. Fusion products of three different protoplasts were obtained in much lower frequency (2.1 x 10(-6)) than those of two different protoplasts (1.2 x 10(-5) to 1.4 x 10(-4)) in the three other combinations. Genetic analyses revealed that triploid fusion products were formed by protoplast fusion of two different strains as well as of three different strains.

Cell Fusion↗