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Biomedical subjects

T Kurihara

Publications and source records attributed to T Kurihara.

At least 163 records · Page 9Linked to original sources
PubMed1995

Purification and properties of a plant beta-D-glucuronidase form Scutellaria root.

beta-D-Glucuronidase (baicalinase, GUS [EC 3.2.1.31]) activity in the crude drug, Scutellaria root, was assayed in line with the quality control standards of Kampo (Japanese Herbal) medicines. GUS was purified to homogeneity in the purification steps including DEAE-Sepharose Fast Flow and chromatofocusing used PBETM94 and Polybuffer 74. These results suggest that the Scutellaria GUS is composed of 55kDa active subunits and that the isoelectric point of this enzyme is pH 5.4. Optimal catalytic activity was found at pH 4.7 in the pH range 3.6--6.2 in 50 mM Na-citrate buffer. The purified enzyme hydrolyzed baicalin and wogonin glucuronide, but did not hydrolyze glycyrrhizin or some beta-glucosides found in other crude drugs. GUS activity in several crude drugs is also described.

Chemical Phenomena↗
PubMed1995

Columbin isolated from calumbae radix affects the sleeping time of anesthetized mice.

In a screening series of bioactive components in edible and medicinal plants, we found that Calumbae Radix (Colombo root, 1% powdered feed, for 5 d) and its component, columbin (20-40 mg/kg/d, for 5 d, orally), shortened the sleeping time induced by a urethane and alpha-chloralose mixture and prolonged the sleeping time induced by hexobarbital in mice.

Anesthesia↗
PubMed1995

[A case of advanced gastric cancer successfully treated with combination chemotherapy using THP, 5'-DFUR and CDDP, followed by surgical resection].

We reported a patient with advanced gastric cancer and a liver metastasis, who responded remarkably to combination chemotherapy using THP, 5'-DFUR and CDDP. The patient was administered four courses of THP (15 mg/m2/day, on day 1, iv), 5'-DFUR (1400 mg/m2/day, on days 1-4 and 15-18, orally), and CDDP (80 mg/m2/day, on day 5, iv) every 4 weeks. As a result, both the primary and metastatic tumors decreased remarkably in size at more than 19 weeks (PR) and we performed curative total resection of the stomach and partial resection of the liver. Histologically, the effects of chemotherapy on gastric focus were evaluated as grade 1a and the liver metastasis completely disappeared. This combination therapy proved useful to treat advanced gastric cancer in this patient.

Adenocarcinoma↗
PubMed1995

[Fatty acid metabolism in patients with idiopathic dilated cardiomyopathy: characteristics and prognostic implications].

The characteristics of myocardial fatty acid metabolism in patients with idiopathic dilated cardiomyopathy (DCM) were investigated by myocardial imaging with beta-methyl-p-[123I]iodophenyl-pentadecanoic acid (BMIPP) in 16 patients with DCM, 8 patients with hypertensive heart failure (HHF), and 11 normal subjects. Rest myocardial imaging with BMIPP and 201Tl was performed on another day. The index of myocardial BMIPP uptake, or uptake ratio, was calculated from the percentage uptakes of BMIPP and 201Tl. The index of inhomogeneity of intramyocardial isotope distribution was calculated as the coefficient of variation of BMIPP and 201Tl. The uptake ratio was significantly lower in DCM and HHF patients than in normal subjects (p < 0.01). Uptake ratio correlated well with fractional shortening (r = 0.76, p < 0.01), and left ventricular ejection fraction (r = 0.58, p < 0.01). Although uptake ratio was not different between DCM and HHF patients, defects in BMIPP imaging appeared more frequently in DCM (69%) than in HHF (38%) patients. Furthermore, the extent of the defect in BMIPP imaging in DCM patients was larger than that in 201Tl imaging (p < 0.05), but in HHF patients the extent of the defects in both methods was similar. The coefficient of variation of BMIPP in DCM patients was greater than those in HHF patients and in normal subjects, but those of 201Tl were not different between the three groups. The coefficient of variation of BMIPP in DCM patients correlated well with serum norepinephrine level (r = 0.57, p < 0.01) and atrial natriuretic peptide (r = 0.77, p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[Assessment of left ventricular contraction kinetics by ECG-gated myocardial SPECT with 99mTc-MIBI: a new attempt with multi-plane long axial tomography].

To investigate left ventricular (LV) contraction kinetics, we performed ECG gated myocardial tomography (gated-SPECT) with 99mTc-MIBI (99mTc methoxy-2-isobutyl isonitrile) at rest. Data were obtained from 32 views and R-R interval was divided into 16. To clarify whether myocardial count change during systole (%CC) reflected LV wall thickening (%WT), we compared septal and posterior %CC in short axis image with %WT which were obtained by echocardiography. And %CC correlated well with %WT (r = 0.86, p < 0.01). In order to assess myocardial contraction kinetics in various parts of LV, multi-plane long axial tomograms were constructed in 10 normal subjects and 9 patients with myocardial infarction (MI). By multi-plane long axial tomography, LV was divided into 17 segments. In each segment %CC was calculated from time activity curves of myocardial count of 99mTc-MIBI. And the disparity of the appearance of peak count in each segment was also observed. In normal subjects %CC was greatest at apex and they decreased from apex to cardiac base. Besides %CC at lateral segments was greater than that in septal segments. Normal range of %CC was determined segment by segment. In normal subjects the intervals from ECG R-wave to peak count were not different in each segment. But in patients with MI they distributed in wide range and prolonged intervals were observed in segments with rest perfusion defect (infarcted segment). In patients with MI decreased %CC was observed in 91% of infarcted segments, in 83% of the segments with exercise induced ischemia and in 89% of the segments with 123I-BMIPP defects. These results indicated decreased %CC represented viable but compromised myocardium as well as necrotic myocardium. In gated-SPECT we obtained useful informations in addition to myocardial perfusion. But it took more than 30 minutes to perform. More experience will be necessary to ascertain the value of this technique.

Adult↗
PubMed1994

Unique primary structure of 2-nitropropane dioxygenase from Hansenula mrakii.

We have isolated the gene encoding 2-nitropropane dioxygenase from Hansenula mrakii, an FAD enzyme that catalyzes the oxygenative denitrification of various anionic nitroalkanes. The gene contained an open reading frame consisting of 1122 nucleotides corresponding to 374 amino acid residues. The protein molecular mass was estimated to be 41,466 Da, which was similar to the subunit molecular mass of the enzyme determined by SDS/PAGE. Several FAD enzymes such as D-amino acid oxidase and glucose oxidase also catalyze the oxidation of nitroalkanes as a side-reaction, although not so efficiently [Kido, T. & Soda, K. (1984) Arch. Biochem. Biophys. 234, 468-475]. However, we found no proteins in the databases (GenBank, EMBL, PIR and SWISS-PROT) which are homologous to 2-nitropropane dioxygenase of H. mrakii in primary structure. No protein motifs, including a nucleotide-binding motif, GXGXXG, were found in PROSITE, a database of biologically significant protein sites and patterns. Accordingly, 2-nitropropane dioxygenase is a new type of flavoprotein with a unique structure.

Amino Acid Sequence↗
PubMed1994

Prenatal ethanol exposure affects the activity and mRNA expression of neuronal membrane enzymes in rat offspring.

In order to elucidate molecular mechanisms underlying brain dysfunction in offspring exposed to ethanol in utero, subclinical doses of ethanol that do not have apparent structural effect on the offspring were administered intraperitoneally to pregnant rats at various gestational stages. We measured the activity of membrane marker enzymes and the level of mRNA of myelin proteins of the offspring brain. The activity of a myelin specific enzyme, 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP) decreased in ethanol-exposed offspring. This effect was not related to the period of gestation or the dose of ethanol. Perikaryonal enzymes, acetylcholinesterase and Na+, K(+)-ATPase, were significantly affected in groups exposed to ethanol at early fetal stage and in high doses. Expression of mRNAs of CNP and myelin basic proteins decreased significantly in the ethanol-treated group, with abnormal developmental profile suggesting a relationship with delayed myelination in offspring exposed to ethanol in utero. The present findings suggest that in spite of the low doses of ethanol that do not cause clinical symptoms in the offspring, prenatal exposure to ethanol affects the level of mRNA of membrane enzyme proteins in the offspring brain, consequently causing a corresponding reduction in enzyme activity, that may lead to neuronal dysfunction. In a separate study, blood ethanol levels were found to reach a maximum level within 30 min after injection and be undetectable after 5 to 10 h. No accumulation effects due to daily injection were observed.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed1994

Microarterial anastomosis with a distal tapering technique.

In microsurgical arterial anastomoses, there are some occasions in which the diameter of the distal artery is much larger than that of the proximal one. A fish-mouth incision technique is useful when there is considerable size discrepancy. However, this method cannot be used when the distal artery is much larger than the proximal artery because turbulent flow and thrombus formation occur, due to the sudden increase of luminal diameter. The distal tapering technique is recommended to prevent turbulent flow. A wedge resection is performed in the distal surplus vessel wall, and there is no sudden change in luminal diameter. Two clinical cases are presented in which this technique was used effectively.

Adult↗
PubMed1994

A hydrophilic tetrahydro-beta-carboline in human urine.

A substance that exhibited a tryptophan-like fluorescence peak at 354 nm on excitation at 295 nm at neutral pH was isolated from human urine. This compound was determined by visible-light absorption spectroscopy, fluorescence spectroscopy, 1H and 13C NMR spectroscopies, and FAB-MS to be 1-(1',2',3',4',5'-pentahydroxypentyl)-1,2,3,4-tetrahydro-2-carboli ne-3- carboxylic acid. This compound, named tetrahydropentoxyline, is a new type of hydrophilic tetrahydro-beta-carboline, and its elution position was between those of 4-pyridoxic acid and kynurenic acid on C18 reversed-phase HPLC. The amount of tetrahydropentoxyline excreted in the urine of normal subjects [n = 21; age, 45 (SD 20) years] was about 5.2 (SD 1.0) mg per day.

Carbolines↗
PubMed1994

Reconsideration of the essential role of a histidine residue of L-2-halo acid dehalogenase.

His20 of L-2-halo acid dehalogenase from Pseudomonas cepacia MBA4 was suggested to serve as a catalytic base [Biochem. J. (1993) 292, 69-74]. In this study, we substituted Asn or Leu for His19 of L-2-halo acid dehalogenase from Pseudomonas sp. YL, which corresponds to His20 of the P. cepacia enzyme. Although the substrate specificity was affected by the substitution, the susceptibilities of substrate halo acids were not substantially diminished, and the Km and kcat values of the mutant enzymes for L-2-chloropropionate were not significantly different from those of the wild-type enzyme. In addition, the wild-type and mutant enzymes showed the same pH optimum. Accordingly, His19 is not essential for catalysis of L-2-halo acid dehalogenase.

Aspartic Acid↗
PubMed1994

Molecular defects of uroporphyrinogen decarboxylase in a patient with mild hepatoerythropoietic porphyria.

The molecular defect of uroporphyrinogen decarboxylase (UROD) was examined in a patient with mild hepatoerythropoietic porphyria. To elucidate the UROD defect, we cloned UROD cDNAs from EBV-transformed lymphoblastoid cells of the proband using reverse transcriptase-polymerase chain reaction. Nucleotide sequence analysis of the cloned UROD cDNAs revealed two separate missense mutations, each occurring in a separate allele. One mutation was a Val134-->Gln transition, and was due to three sequential point mutations (T417G418T419-->CCA); the other mutation was a His220-->Pro transition (A677-->C). UROD phenotype studies demonstrated that the TGT-->CCA mutation was inherited from the father, and the A-->C mutation was inherited from the mother. In contrast to the null activity previously described for a mutant UROD from a patient with familial porphyria cutanea tarda, these mutant URODs had subnormal but substantial enzyme activities, when expressed in Chinese hamster ovary cells. This is the first demonstration of a mutation caused by three sequential base substitutions.

Adult↗
PubMed1994

Increased rate of spontaneous mitotic recombination in T lymphocytes from a Bloom's syndrome patient using a flow-cytometric assay at HLA-A locus.

Bloom's syndrome (BS) is an autosomal recessive disorder conferring high propensity for cancer and displaying a high degree of genetic instability; the frequency of sister chromatid exchange is characteristically 10 times above background. The symmetrical four-armed chromatid interchanges are much more readily detected in peripheral blood lymphocytes of BS patients, suggesting that the frequency of somatic recombination is also increased. In the present study, the rate of spontaneous loss of HLA-A allele expression was estimated following fluctuation analysis in cultured T lymphocytes using a flow-cytometric assay. It was found to be 10 times or more higher than normal in lymphocytes from a BS patient. Molecular and chromosome analyses showed that all 13 independent variants from the patient were most likely derived from somatic recombinations. Further tests for loss of heterozygosity at a closely linked proximal locus, HLA-DQA1, showed that as many as half of the recombinants retained heterozygosity irrespective of the donor. The results suggest that the HLA region is hyperrecombinogenic in somatic cells and that the elevated recombination rate in BS cells results from the general increase at ordinary sites and not from random creation of unusual sites for recombination.

Adult↗
PubMed1994

Solid-phase synthesis of human osteocalcin by using a gamma-carboxyglutamic acid derivative.

Human osteocalcin, also called bone Gla protein (BGP), consisting of 49 amino acids with two or three gamma-carboxyglutamate residues, was chemically synthesized for the first time by a novel solid-phase peptide synthesis. An L-enantiomer of N-tert-butyloxycarbonyl-gamma,gamma'-dicyclohexyl-gamma-carboxyglutamic acid was designed, prepared and utilized as a monomeric compound and proven to be useful for the solid-phase peptide synthesis of human osteocalcin. The synthesis and optical resolution of the gamma-carboxyglutamic acid (Gla) derivative are first described, followed by the synthesis and characterization of Gla17-human osteocalcin.

1-Carboxyglutamic Acid↗
PubMed1994

Invasive ductal carcinoma with a predominant intraductal component arising in a fibroadenoma of the breast.

A rare case of invasive ductal carcinoma with a predominant intraductal component arising within a fibroadenoma of the breast in a 42 year old Japanese female was investigated by light microscopy. The patient, who had a well-defined, rubbery breast tumor measuring 2.0 x 3.0 cm, had undergone a tumorectomy 21 months after she noticed the tumor. Histologically, the fundamental architecture of the tumor showed an intracanalicular-type of fibroadenoma, but extensive proliferation of atypical cells was noticed in the lumen of the ducts. Tumor cells in the canaliculi had characteristics of ductal carcinoma, such as solid, comedo and cribriform patterns. As most of the ducts were occupied by carcinoma cells with several foci of microinvasion in the stroma of the fibroadenoma, it was diagnosed as invasive ductal carcinoma with a predominant intraductal component arising within a fibroadenoma. This coexistence of in situ proliferation and invasive lesions of carcinoma within a fibroadenoma suggest the origin of the carcinoma to have been in the epithelial component of the fibroadenoma. In addition, this study clarifies the fact that carcinoma cells may proliferate and spread along the lumen of pre-existing ducts of the fibroadenoma and speculates that the duct system of the fibroadenoma has complete continuity.

Adult↗
PubMed1994

Involvement of enzymatic degradation in the inactivation of tachykinin neurotransmitters in neonatal rat spinal cord.

1. The possible involvement of enzymatic degradation in the inactivation of tachykinin neurotransmitters was examined in the spinal cord of the neonatal rat. 2. The magnitude of substance P (SP)- or neurokinin A (NKA)-evoked depolarization of a lumbar ventral root in the isolated spinal cord preparation was increased by a mixture of peptidase inhibitors, consisting of actinonin (6 microM), arphamenine B (6 microM), bestatin (10 microM), captopril (10 microM) and thiorphan (0.3 microM). The mixture augmented the response to NKA more markedly than that to SP. 3. In the isolated spinal cord-cutaneous nerve preparation, the saphenous nerve-evoked slow depolarization of the L3 ventral root was augmented by the mixture of peptidase inhibitors in the presence of naloxone (0.5 microM) but not in the presence of both naloxone and a tachykinin receptor antagonist, GR71251 (5 microM). 4. Application of capsaicin (0.5 microM) for 6 min to the spinal cord evoked an increase in the release of SP from the spinal cord. The amount of SP released was significantly augmented by the mixture of peptidase inhibitors. 5. Synaptic membrane fractions were prepared from neonatal rat spinal cords. These fractions showed degrading activities for SP and NKA and the activities were inhibited by the mixture of peptidase inhibitors. The degrading activity for NKA was higher than that for SP and the inhibitory effect of the mixture for NKA was more marked than that for SP. Although some other fractions obtained from homogenates of spinal cords showed higher degrading activities for SP, these activities were insensitive to the mixture of peptidase inhibitors. 6. Effects of individual peptidase inhibitors on the enzymatic degradation of SP and NKA by synaptic membrane fractions were examined. Thiorphan, actinonin and captopril inhibited SP degradation, while thiorphan and actinonin, but not captopril, inhibited NKA degradation. The potency of the inhibition of each peptidase inhibitor was lower than that of the mixture.7. The present results suggest that enzymatic degradation is involved in the inactivation of tachykinin neurotransmitters in the spinal cord of the neonatal rat.

Animals↗
PubMed1994

Purification and characterization of thermostable and nonthermostable 2-haloacid dehalogenases with different stereospecificities from Pseudomonas sp. strain YL.

Two novel hydrolytic dehalogenases, thermostable L-2-haloacid dehalogenase (L-DEX) inducibly synthesized by 2-chloropropionate (2-CPA) and nonthermostable DL-2-haloacid dehalogenase (DL-DEX) induced by 2-chloroacrylate, were purified to homogeneity from Pseudomonas sp. strain YL. DL-DEX consisted of a monomer with a molecular weight of about 36,000 and catalyzed the dehalogenation of L and D isomers of 2-CPA to produce D- and L-lactates, respectively. It acted on 2-haloalkanoic acids with a carbon chain length of 2 to 4. The maximum activity on DL-2-CPA was found at pH 10.5 and 45 degrees C. L-DEX, composed of two subunits with identical molecular weights of 27,000, catalyzes the dehalogenation of L-2-haloalkanoic acids to produce the corresponding D-2-hydroxyalkanoic acids. The enzyme acts not only on short-carbon-chain 2-haloacids such as monochloroacetate and monoiodoacetate in aqueous solution but also on long-carbon-chain 2-haloacids such as 2-bromohexadecanoate in n-heptane. L-DEX is thermostable: it retained its full activity upon heating at 60 degrees C for 30 min. The pH and temperature optima for dehalogenation of L-2-CPA were 9.5 and 65 degrees C, respectively. L-DEX was strongly inhibited by modification of carboxyl groups with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and Woodward reagent K, but DL-DEX was not.

Amino Acid Sequence↗