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Biomedical subjects

A Kimura

Publications and source records attributed to A Kimura.

At least 19 recordsLinked to original sources
PubMed1996

Identification of the structural gene for glyoxalase I from Saccharomyces cerevisiae.

The structural gene for glyoxalase I (GLO1) of Saccharomyces cerevisiae was identified. The GLO1 gene contained an open reading frame with 326 amino acids, and the molecular weight of the gene product (Glo1p) deduced from the DNA sequence was calculated to be 37,207.06. Glyoxalase I activity increased approximately 95-fold when the GLO1 gene was introduced into the yeast cell with a multicopy plasmid, and the resultant transformant showed the increased resistance against methylglyoxal. Since the knockout mutant of the GLO1 gene of haploid strain of S. cerevisiae was still viable, the GLO1 gene was thought to be unnecessary for growth of the yeast. The GLO1 gene was overexpressed in two kinds of glutathione-deficient mutants, gamma-glutamylcysteine synthetase-deficient (gsh1(-)) and glutathione synthetase-deficient (gsh2(-)), respectively, and the sensitivites to methylglyoxal were compared. The gsh1-deficient mutant, which could not produce glutathione at all, was hypersensitive to methylglyoxal, and overproduction of the Glo1p did not restore the growth arrest caused by exogenously added methylglyoxal. The gsh2-deficient mutant, which accumulates gamma-glutamylcysteine (an intermediate of glutathione biosynthesis), was also sensitive to methylglyoxal compared with the isogenic wild type strain, although the growth arrest caused by methylglyoxal was partially restored by overexpression of the GLO1 gene. Purified glyoxalase I from yeast could use gamma-glutamylcysteine as a substrate (kcat/Km = 1.89 x 10(7) M-1 s-1, glutathione; 3.47 x 10(4) M-1 s-1, gamma-glutamylcysteine).

Amino Acid Sequence↗
PubMed1996

NAD+ biosynthesis and metabolic fluxes of tryptophan in hepatocytes isolated from rats fed a clofibrate-containing diet.

Hepatocytes were isolated from rats fed a diet with or without 0.25% clofibrate, and NAD+ synthesis by the hepatocytes was determined using either [carboxyl-14C]nicotinic acid or [5-3H]tryptophan. NAD+ and total pyridine nucleotides synthesized from [14C]nicotinic acid by the clofibrate-treated cells were not significantly different from those synthesized by the control cells when expressed on the basis of nanomoles per hour per milligram of DNA. On the contrary, NAD+ synthesized from [3H]tryptophan was significantly higher in the clofibrate-treated cells (158% of the control cells) on the basis of nanomoles per hour per milligram of DNA. Clofibrate was inhibitory to tryptophan metabolism as a whole, affecting the glutarate pathway more (decreased to 37% of control) than the kynureninase flux (decreased to 64% of control). As a result, the quinolinate-NAD flux, estimated as the difference in the amounts of tryptophan metabolized by the two metabolic pathways, increased in the clofibrate-treated hepatocytes. The increase in quinolinate during the incubation was 8 times more in the clofibrate-treated cells than in the control cells, which confirmed alteration in the metabolic fluxes of tryptophan in the clofibrate-treated cells. Hepatic quinolinate phosphoribosyltransferase (EC 2.4.2.19) activity increased with dietary clofibrate and returned to the control level 1 week after removing clofibrate from the diet. Nicotinate phosphoribosyltransferase (EC 2.4.2.11) and NAD+ glycohydrolase (EC 3.2.2.5) activities remained unchanged with dietary clofibrate.

Animals↗
PubMed1996

Single electrical shock of a somatic afferent nerve elicits A- and C-reflex discharges in gastric vagal efferent nerves in anesthetized rats.

The possibility that single electrical shock stimulation of somatic afferent nerves could evoke a reflex response in vagal efferent nerves innervating the stomach was examined using anesthetized, artificially-ventilated rats. A single shock to a hindlimb afferent nerve (tibial nerve) produced two distinct reflex components in gastric vagal efferent nerves; namely (1) A-reflex discharges with a latency of about 120 ms and a duration of about 200 ms elicited by stimulation of myelinated A afferent fibers, and (2) C-reflex discharges with a latency of about 360 ms and a duration of about 200 ms elicited by stimulation of unmyelinated C afferent fibers. A single shock to a first lumbar spinal afferent nerve produced only a week reflex component with a latency of about 120 ms and a duration of about 190 ms in gastric vagal efferent nerves. Limb afferents appear to have stronger central pathways functionally connecting to gastric vagal efferent preganglionic neurons in the brainstem, than do abdominal afferents.

Anesthesia↗
PubMed1996

Long-lasting changes of neuronal activity in the motor cortex of cats.

The effect of tetanic intracortical microstimulation (ICMS) of superficial layers of the motor cortex on unit discharges responding to stimulation of the peripheral receptive fields was examined in the motor cortex (area 4y). Single or multiple unit discharges were isolated from 15 recording sites near the stimulating electrodes. Following tetanic ICMS, the response to the same peripheral stimulation showed a long lasting increase at six recording sites, a long lasting decrease at two sites and transient increase or decrease at four sites. In the rest of the sites, tetanic ICMS had no effect. The results demonstrate the existence of use-dependent modification of information processing in the motor cortex and support the hypothesis that the motor cortex participates in learning motor skills.

Animals↗
PubMed1996

Effects of intraaortic balloon pumping on septal arterial blood flow velocity waveform during severe left main coronary artery stenosis.

OBJECTIVES: We sought to evaluate the effect of intraaortic balloon pumping on the phasic blood velocity waveform into myocardium with severe coronary artery stenosis. BACKGROUND: In the presence of severe coronary artery stenosis, it is not clear whether intraaortic balloon pumping augments intramyocardial inflow during diastole or changes systolic retrograde blood flow from the myocardium to the extramural coronary arteries. METHODS: Using anesthetized open chest dogs (n=7), we introduced severe stenosis in the left main coronary artery to reduce the poststenotic pressure to approximately 60 mm Hg (>90% diameter stenosis). Septal arterial blood flow velocities were measured with a 20-MHz, 80-channel ultrasound pulsed Doppler velocimeter. Left anterior descending arterial flow, aortic pressure and poststenotic distal coronary pressure were measured simultaneously. The diastolic anterograde flow integral and systolic retrograde flow integral were compared in the presence and absence of intraaortic balloon pumping. RESULTS: Although intraaortic balloon pumping augmented diastolic aortic pressure, this pressure increase was not effectively transmitted through stenosis. Septal arterial diastolic flow velocity was not augmented, and left anterior descending arterial flow was unchanged during intraaortic balloon pumping. CONCLUSIONS: In the presence of severe coronary artery stenosis, intraaortic balloon pumping failed to increase diastolic inflow in the myocardium and did not enhance systolic retrograde flow from the myocardium to the extramural coronary artery. Thus, the major effect of intraaortic balloon pumping on the ischemic heart with severe coronary artery stenosis may be achieved by reducing oxygen demand by systolic unloading.

Analysis of Variance↗
PubMed1996

Association between the DRB1*08032 histocompatibility antigen and methimazole-induced agranulocytosis in Japanese patients with Graves disease.

OBJECTIVE: To determine the association between HLA class II genes and methimazole-induced agranulocytosis in patients with Graves disease. DESIGN: Case-control study. SETTING: Kuma Hospital, which specializes in thyroid diseases, in Kobe, Japan. SUBJECTS: 24 patients with Graves disease who had methimazole-induced agranulocytosis diagnosed by peripheral granulocyte counts of less than 0.5 x 10(9)/L, and 68 patients with Graves disease treated with methimazole, who were free from agranulocytosis. Controls were 525 healthy, unrelated Japanese student volunteers at Kyushu University in Japan. MEASUREMENTS: All HLA class II genes were analyzed for polymorphisms at the DNA level by using the polymerase chain reaction sequence-specific oligonucleotide probes method. The allele frequencies in the agranulocytotic Graves disease group were compared with those in the nonagranulocytotic Graves disease and control groups. RESULTS: A strong positive association was seen in DRB1*08032 between the agranulocytotic group and both the control and nonagranulocytotic Graves disease groups. CONCLUSION: The HLA DRB1*08032 allele was strongly associated with susceptibility to methimazole-induced agranulocytosis, suggesting that cellular autoimmunity may be involved in its development.

Agranulocytosis↗
PubMed1996

Serum concentrations of total bile acids in patients with acute Kawasaki syndrome.

OBJECTIVES: To investigate serum concentrations of total bile acids (TBAs) in patients with acute Kawasaki syndrome (KS) and correlate those concentrations with other liver function test results. PATIENTS AND METHODS: Seventy-one Japanese patients with KS (mean age, 1.6 years). Blood samples from 29 patients were obtained during the acute and convalescent phases of KS. RESULTS: Elevated serum TBA concentrations higher than 20 micromol/L were detected in 16 (22.5%) of the patients with acute KS. Serum concentrations of TBAs gradually returned to normal (P=.001, Pearson's correlation coefficient). The mean +/- SD serum concentration of TBAs of patients during the acute phase (37.9 +/- 63.9 micromol/L) was significantly higher than that of patients during the convalescent phase (7.2 +/- 7.5 micromol/L) (P=.02, Pearson's correlation coefficient). The data show a correlation between the serum concentrations of TBAs with those of alanine aminotransferase (P=.03, Pearson's correlation coefficient), total bilirubin (P<.001, Pearson's correlation coefficient), and C-reactive protein (P=.01, Pearson's correlation coefficient) measured during the acute phase. CONCLUSIONS: The cause of the elevated concentration of serum TBAs in patients with acute KS is unclear. Increased bile acid synthesis from cholesterol may occur, or patients with acute KS may suffer from damage to the bile duct cells of their biliary systems caused by cytokine activation. This damage may depress bile acid excretion, thereby increasing the serum concentrations of TBAs.

Acute Disease↗
PubMed1996

DNA typing of HLA class II genes in Japanese patients with rheumatic heart disease.

To study further the association between HLA and rheumatic valvular disease, DNA typing HLA class II genes (DRB1, DQA1, DQB1 and DPB1) was performed in 72 unrelated Japanese patients with predominant mitral stenosis and 525 unrelated Japanese healthy controls, based on the polymerase chain reaction in combination of dot-blot hybridization with sequence-specific oligonucleotide probes. As compared with controls. Patients with mitral stenosis showed increased frequencies of DQA1*0104 (18.1% v 7.2%; RR = 2.82, P = 0.002, Pc = 0.03) and DQB1*05031 (13.9% v 4.8%: RR = 3.23, P = 0.002, Pc = 0.05). In contrast, no significant deviation in the frequencies of DRB1, DPA1 or DPB1 alleles was observed in the patients. These observations suggest that the susceptibility to mitral stenosis is in part controlled by a gene (or genes) in close linkage disequilibrium with HLA-DQA1*0104 and DQB1*05031, i.e. the susceptibility gene may be mapped within the HLA-DQ region.

Adult↗
PubMed1996

Two-Dimensional NMR Study of a Liquid-Crystal Solution under Magic-Angle Spinning. Conformation of Carboxylic Ionophore Lasalocid A Dissolved in a Lyotropic Liquid Crystal

The conformation of a carboxylic ionophore, lasalocid A, has been determined in a lyotropic liquid crystal by means of magic-angle spinning (MAS) and two-dimensional NMR experiments. The information extracted from ROESY spectra measured under MAS was analyzed according to the distance-geometry algorithm. The liquid crystal used for the solvent is cesium perfluorooctanoate dissolved in D2O, and the resulting structure of lasalocid A is a cyclic one, indicating cation complexation within a hydrophobic region of the liquid crystal. In this way, the two-dimensional MAS NMR experiment is proved to be a useful technique in conformational studies of complex molecules dissolved in lyotropic liquid crystal which may be regarded as offering a membrane-like environment.

Journal Article↗
PubMed1996

A case of choledocholithiasis with an endoclip nidus, 6 months after laparoscopic cholecystectomy.

A 69-year-old man developed obstructive jaundice 6 months after laparoscopic cholecystectomy. Endoscopic retrograde cholangiography suggested a common bile duct (CD) stone. A second operation was performed, and this revealed a CBD stone with an endoclip as a nidus. Since laparoscopic surgery has become a very common procedure, endoclips are used more frequently. Therefore, careful surveillance and strict follow-up are stressed to avoid CBD stone and various other complications caused by endoclips.

Aged↗
PubMed1996

Two N-acetyl-D-galactosamine-specific lectins from Phaeolepiota aurea.

Two lectins, PAL-I and PAL-II, were isolated from the mushroom Phaeolepiota aurea by affinity chromatography on acid-treated Sepharose CL-4B followed by reverse-phase FPLC on ProRPC. Both of the lectins were tetramers of 16 kDa subunits. The lectins had little agglutination activity against native erythrocytes but Pronase treatment of erythrocytes increased the sensitivity to agglutination by the lectins. Both lectins exhibited slight preferences for type A compared with type B and O erythrocytes. In haemagglutination inhibition assays, N-acetylgalactosamine and both anomers of methyl N-acetylgalactosaminide were the best inhibitors.

Acetylgalactosamine↗
PubMed1996

A- and C-reflexes elicited in cardiac sympathetic nerves by single shock to a somatic afferent nerve include spinal and supraspinal components in anesthetized rats.

The spinal and supraspinal components of both A- and C-reflexes were studied in the somato-cardiac sympathetic reflex discharges elicited by a single electrical shock either to a spinal (T3-4) afferent nerve or to a limb (tibial) afferent nerve in urethane anesthetized rats. In central nervous system (CNS) intact rats, a single shock to a T3-4 spinal afferent nerve produced early and late A-reflex discharges with latencies of 20 +/- 1 ms and 62 +/- 6 ms, respectively, and a C-reflex with a latency of 136 +/- 9 ms in a cardiac sympathetic efferent nerve. After spinalization at the first cervical level, stimulation of the same spinal afferent nerve produced an A-reflex with the same latency as the early A-reflex in CNS-intact rats and a C-reflex with a latency of 86 +/- 3 ms. The amplitude of the early A-reflex became augmented after spinal transection. On the other hand, a single shock to a tibial afferent nerve evoked an A-reflex discharge with a latency of 41 +/- 2 ms and a C-reflex discharge with a latency of 210 +/- 13 ms in CNS-intact rats. These A- and C-reflexes elicited by stimulation of a tibial afferent nerve were not observed after spinalization. It was concluded that cardiac sympathetic A- and C-reflex discharges evoked by stimulation of a segmental spinal afferent nerve in CNS-intact rats are of spinal and supraspinal origin, and those evoked by tibial nerve stimulation are of supraspinal origin. The spinal reflex pathway is segmentally organized, because the spinal reflex is evoked only when stimulation is delivered to afferent nerves close to the cardiac sympathetic outflow segments. With the CNS intact, the spinal reflex component is depressed by descending inhibitory pathways originating in the brain.

Adrenergic Fibers↗
PubMed1996

Increased expression of a brain/embryo-type myosin heavy chain isoform (MIIB2) in mesangial proliferative glomerulonephritis.

Proliferation of mesangial cells is frequently found in glomerulonephritis, such as IgA glomerulonephritis. Recent reports suggest that a brain/embryo-type myosin isoform (MIIB2) is involved in cell proliferation. We have studied the expression of MIIB2 in renal biopsy samples from patients with various renal diseases and in the renal tissues from the rat model of mesangial proliferative glomerulonephritis induced with anti-Thy 1.1 antibody. Immunohistochemical analysis of the biopsy samples using an anti-brain-type myosin heavy chain-specific monoclonal antibody (HBM1) indicated that 92% of the samples from patients with IgA glomerulonephritis contained a significant population of mesangial cells that reacted with the antibody. Most of the samples from patients with other types of proliferative glomerular diseases also contained HBM1-reactive mesangial cells, while none of the samples from patients with non-proliferative glomerular diseases contained a significant population of HBM1-reactive mesangial cells. The expression of a brain/embryo-type myosin heavy chain isoform (MIIB2) in the mesangial cells began at five days after injection of anti-Thy 1.1 antibody and peaked at the tenth day. On the other hand, the expression of the proliferating cell nuclear antigen in the mesangial cells was induced at two days after injection of anti-Thy 1.1 antibody and was maximal at the fourth day. These results indicate that the expression of the MIIB2 isoform by mesangial cells is accelerated in proliferative glomerulonephritis and suggest that the myosin isoform is involved in the phenotypic transformations of the glomerular tissues rather than in the cell proliferation.

Adolescent↗
PubMed1996

Decreased L-selectin expression in CD34-positive cells from patients with chronic myelocytic leukaemia.

Abnormal adhesive interaction between bone marrow stroma and progenitors, one of the causes of unregulated proliferation in chronic myelocytic leukaemia (CML), may be caused by some alterations in adhesion molecules on CML progenitors. We investigated the expression of adhesion molecules (CD44, VLA-5, VLA-4, LFA-1, ICAM-1, L-selectin and c-kit) on bone marrow CD34++ cells from 16 CML patients by three-colour flow cytometry. The mean percentage of cells expressing L-selectin in the CD34++CD38+(or)++ fraction from untreated CML patients was significantly lower, and that in the CD34++CD38- fraction tended to be lower than that from normal controls. Among 11 CML patients treated with interferon-alpha (IFN-alpha), the mean percentage of the cells expressing L-selectin in the CD34++CD38- fraction from three patients with a low percentage of Ph1(+) cells in bone marrow was significantly higher than that from five patients with a high percentage of Ph1(+) cells. In addition, L-selectin expression rate was inversely correlated to the percentage of Ph1(+) cells. There was no significant difference between the untreated patients and normal controls with regard to the expression rates of the other adhesion molecules in each CD34++ fraction except LFA-1. These data suggest that decreased L-selectin expression in CML CD34++ cells reflects one of the features of malignant CML progenitors.

ADP-ribosyl Cyclase↗
PubMed1996

Assessment of microchimerism in rat liver transplantation by polymerase chain reaction.

Mixed chimerism has been demonstrated in organ transplant recipients surviving over a long period. However, little is known about the fate and movements of donor cells following liver transplantation. In this study, using rat male-to-female liver transplantation, we assessed microchimerism by semiquantitative polymerase chain reaction (PCR). A PCR specific for the Y-chromosome (sex-determining region Y [Sry]) allowed the distinction of small amounts of male cells in a large excess of female cells. Nonimmunosuppressed Lewis recipients of Lewis liver grafts survived >60 days, and donor cells were detected in peripheral blood up to day 60 in four of six recipients. All immunosuppressed Lewis recipients survived for 60 days, and the donor cells were detected up to day 60. Semiquantitative PCR demonstrated that in immunosuppressed Lewis recipients surviving >60 days with no acute rejection episode, the donor-to-recipient cell ratio remained >1:1,000. In nonimmunosuppressed Lewis recipients of ACI liver allografts, donor cells in peripheral blood decreased rapidly by day 7. In immunosuppressed Lewis recipients of ACI liver allografts, donor cells were detected for longer periods, in proportion to the amount and duration of FK506 (Fujisawa Pharmaceutical Co., Osaka, Japan) administered. However, in recipients with deteriorating function due to ongoing rejection, small amounts (0.01 percent) of donor cells were detected. Our results indicate that the Sry-specific PCR is useful for assessing microchimerism following rat liver transplantation, and demonstrate correlation between microchimerism and graft outcome; high-level microchimerism (>O.l percent) correlated well with graft acceptance, whereas low-level microchimerism (<O.01 percent) did not.

Animals↗
PubMed1996

A solitary Peutz-Jeghers-type hamartomatous polyp of the rectum: report of a case and review of the literature.

A solitary Peutz-Jeghers-type polyp of the rectum in a 64-year-old Japanese man is reported. Barium enema and endoscopic examination revealed a solitary polypoid lesion in the rectum. The polyp was pedunculated, and measured 2 x 1.5 x 1.5 cm. The patient had neither mucocutaneous pigmentation nor a family history of gastro-intestinal polyposis. Histopathologically, this polyp had an arborizing muscular network originating from the muscularis mucosa, and was covered by well organized mucosa with epithelial hyperplasia. The smooth muscle bundles in the polyp were thicker than those seen in Peutz-Jeghers syndrome, but their network was not as complex.

Hamartoma↗