Biomedical subjects

M Shibata

Publications and source records attributed to M Shibata.

At least 217 records · Page 12Linked to original sources

PubMed1998

Amrinone, a selective phosphodiesterase III inhibitor, improves microcirculation and flap survival: a comparative study with prostaglandin E1.

BACKGROUND: Amrinone, a selective phosphodiesterase (PDE) III inhibitor, is a newly developed agent that possesses a combination of positive inotropic and vasodilating properties as a result of preventing the degradation of cAMP and it has recently been licensed for treatment of heart failure alone. Amrinone is expected to be useful for the treatment not only of heart failure but also of peripheral circulatory disorders, including vascular disease, and for ischemic flaps, because it improves microcirculatory hemodynamics. To investigate potential therapeutic applications of amrinone, we evaluated its ability to improve microcirculatory hemodynamics and flap survival. MATERIALS AND METHODS: The rat skinfold chamber technique was employed to quantify microcirculation directly in vivo. The improved survival area of random flaps in rats treated with amrinone was examined to assess therapeutic efficacy of this drug. Its effects were compared with those of prostaglandin E1 (PGE1), which has been widely approved as an agent for improving hemodynamics. RESULTS: Microcirculatory blood flow and flap survival area were significantly increased in both amrinone- and PGE1-treated animals, compared to the saline-treated controls. The ameliorating effects of amrinone were comparable to those of PGE1. CONCLUSIONS: The results of this study suggest amrinone to be a potentially useful drug not only for treating heart failure but also for improving microcirculation in patients with vascular diseases and for postoperative care after reconstructive surgery.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed1998

ATP synthesis by F0F1-ATP synthase independent of noncatalytic nucleotide binding sites and insensitive to azide inhibition.

ATP hydrolyzing activity of a mutant alpha3beta3gamma subcomplex of F0F1-ATP synthase (DeltaNC) from the thermophilic Bacillus PS3, which lacked noncatalytic nucleotide binding sites, was inactivated completely soon after starting the reaction (Matsui, T., Muneyuki, E. , Honda, M., Allison, W. S., Dou, C., and Yoshida, M. (1997) J. Biol. Chem. 272, 8215-8221). This inactivation is caused by rapid accumulation of the "MgADP inhibited form" which, in the case of wild-type enzyme, would be relieved by ATP binding to noncatalytic sites. We reconstituted F0F1-ATP synthase into liposomes together with bacteriorhodopsin and measured illumination-driven ATP synthesis. Remarkably, DeltaNC F0F1-ATP synthase catalyzed continuous turnover of ATP synthesis while it could not promote ATP-driven proton translocation. ATP synthesis by DeltaNC F0F1-ATP synthase, as well as wild-type enzyme, proceeded even in the presence of azide, an inhibitor of ATP hydrolysis that stabilizes the MgADP inhibited form. The time course of ATP synthesis by DeltaNC F0F1-ATP synthase was linear, and gradual acceleration to the maximal rate, which was observed for the wild-type enzyme, was not seen. Thus, ATP synthesis can proceed without nucleotide binding to noncatalytic sites even though the rate is sub-maximal. These results indicate that the MgADP inhibited form is not produced in ATP synthesis reaction, and in this regard, ATP synthesis may not be a simple reversal of ATP hydrolysis.

Adenosine Triphosphate↗

PubMed1998

In vivo measurement of morphometric and hemodynamic changes in the microcirculation during angiogenesis under chronic alpha1-adrenergic blocker treatment.

The effect of chronic administration of the alpha 1 blocker prazosin on microvascular angiogenesis was studied in rabbit ear chamber to investigate the role of concomitant increase in flow-oriented wall shear stress in vascular remodeling during angiogenesis. Rabbits were treated with prazosin hydrochloride (50 mg/liter in water) orally after ear chambers were installed. The microcirculation in the chamber was observed and recorded from 4 to 23 postoperative day (POD) by an intravital videomicroscope. The total vascular area (TA) were quantified as a morphometric parameter. Changes in wall shear stress in venules (20-40 micron ID) were calculated from flow velocity, vessel diameter, and in vivo blood viscosity. TA was significantly increased in the prazosin-treated animals. The levels of shear stress, which was increased 1.43 times by prazosin on 9 POD, gradually decreased toward the control level on 13 POD and they almost coincided on 21 POD. These findings experimentally provided supporting evidence that shear stress is probably involved in the adaptive response as one of mechanical factors regulating vascular remodeling during angiogenesis.

Adrenergic alpha-Antagonists↗

PubMed1998

Biological effects of static magnetic fields on the microcirculatory blood flow in vivo: a preliminary report.

There have been few studies of the effect of static magnetic fields on microcirculatory haemodynamics in vivo. The rat skinfold transparent chamber technique was used, which provides an excellent means of observing and quantifying direct in vivo microvascular haemodynamic responses to static magnetic fields up to 8 T. An intravital videomicroscope was used to measure the changes in blood flow before and after exposure to a magnetic field for 20 min in a horizontal type superconducting magnet with a bore 100 mm in diameter and 700 mm long. After exposure, microcirculatory blood flow showed an initial increase for about 5 min followed by a gradual decrease and a return to the control value. It is hypothesised that these changes represent rebound hyperaemia following reduced blood flow during exposure.

Animals↗

PubMed1998

Increased serum concentrations of soluble tumor necrosis factor receptor I in noncachectic and cachectic patients with advanced gastric and colorectal cancer.

The serum levels of soluble tumor necrosis factor receptor I (sTNF-RI) were measured in 74 noncachectic patients including 42 with gastric cancer and 32 with colorectal cancer, as well as in 39 patients with severe cachexia and 15 healthy volunteers. The sTNF-RI levels increased with the advance of disease, being highest in the cachectic patients. The levels were inversely correlated with the serum concentrations of nutritional parameters such as prealbumin, transferrin, retinol binding protein, and the percentages of CD3(+) cells in the peripheral blood lymphocytes, and positively correlated with the serum concentration of immunosuppressive acidic protein (IAP) and soluble interleukin-2 receptors. These findings suggest that sTNF-RI could be an important prognostic factor to predict the advance of gastric and colorectal cancers and deterioration of the patient's nutritional and immune activity.

Antigens, CD↗

PubMed1998

Expression and localization of ferritin mRNA in ameloblasts of rat incisor.

At the maturation stage, the ameloblasts of the rat incisor incorporate iron, supplied through the bloodstream, and deposit it into the surface layer of the enamel. In this unique iron transport system, ferritin functions as a transient iron reservoir in the cells. Here the expression of ferritin mRNA and its localization in the rat enamel organ was examined. Among various tissues, the enamel organ showed the highest expression for both ferritin H- and L-chain mRNA, as quantified by reverse transcription-polymerase chain reaction. In situ hybridization using digoxigenin-labelled cRNA probes for each chain demonstrated that both ferritin H- and L-chain mRNA were abundantly expressed in presecretory and secretory ameloblasts. The intensity of the positive hybridization signal gradually decreased toward the incisal direction. Differing from the mRNA localization, ferritin protein was immunologically undetectable in presecretory or secretory ameloblasts but was found in ameloblasts at the maturation stage, into which iron is known to be incorporated from the bloodstream. Thus, the expression of ferritin mRNA precedes the protein expression in the developmental stages of rat incisor ameloblasts, and the translation of ferritin and its half-life are probably controlled by the iron entry, as has been reported for other cell types.

Ameloblasts↗

PubMed1998

Infant cold exposure changes Fos expression to acute cold stimulation in adult hypothalamic brain regions.

It is known that cold exposure as an infant results in a permanent cold tolerance which is accompanied by a reduced rate of colonic temperature decline and increased metabolic heat production to cold stimulation. The present study was aimed to elucidate the central mechanism of cold tolerance of adult rats with cold exposure as infants. Newborn infants were exposed to cold ambient (4 degrees C) daily for 2 weeks, and when they were 15-weeks old, Fos expression to acute cold stimulation (10 degrees C) in whole brain regions was investigated using quantitative immunohistochemistry. Acute cold stimulation induced a significant increase of Fos-positive neurons in many nuclei of whole brain areas in adult rats both with and without cold exposure as infants. However, the number of Fos-positive neurons was significantly less in the rats with cold exposure than without cold exposure as infants, particularly in the hypothalamic nuclei such as the lateral septal nucleus (LS), preoptic area (POA), parvocellular paraventricular nucleus (pPVN0, ventromedial hypothalamic nucleus (VMH) and supramammillary nucleus (SuM). However, there was no significant difference in the number of Fos-positive neurons in the extra-hypothalamic regions between the rats with and without cold exposure as infants. These results suggest that the central mechanism of cold tolerance with cold exposure as infants is due to metabolic changes of the hypothalamic brain regions.

Animals↗

PubMed1998

Hyperthermia in brain hemorrhage.

Hemorrhage in the midbrain and/or pons in patients is often associated with increased metabolism, resulting in hyperthermia. We have recently reported that hyperthermia develops in anesthetized rats following prepontine knife-cuts or procaine microinjections into the midbrain or upper pontine region. It was concluded that the hyperthermia in the animals was caused by the removal of a tonic inhibitor mechanism of heat production that exists in the lower midbrain. The present paper proposes a new hypothesis that the hyperthermia in patients with brainstem hemorrhage is caused by disinhibition of heat production due to the release of such a lower-midbrain mechanism.

Adipose Tissue, Brown↗

PubMed1998

Beta-decay half-lives and level ordering of 102m,gRh.

Beta-decay half-lives of the ground state and an isomer of 102Rh have been determined 207.3(17) d and 3,742(10) y, respectively, by gamma-ray decay curves following each beta-decay. It has been found that a state (2-) which has a shorter half-life (207.3 d) is the ground state from the result that the half-life of the 41.9 keV isomeric gamma-transition was equal to 3.742 y. It has also been confirmed that the 41.9 keV transition is certainly an isomeric transition with X-gamma coincidence measurement.

Beta Particles↗

PubMed1998

Bone marrow infarction due to acute graft-versus-host disease in an acute lymphoblastic leukemia patient after unrelated bone marrow transplantation.

We report a case of bone marrow infarction in a 20-year-old woman with acute lymphocytic leukemia (ALL) who underwent unrelated bone marrow transplantation (BMT). Hematopoietic engraftment occurred on day 9 and, thereafter, the patient developed acute dermal and hepatic graft-versus-host disease (GVHD). She also experienced severe arthralgia in her knee joints on day 21. Immunosuppressive therapy with prednisolone (PSL) for acute GVHD was given, and the arthralgia improved rapidly, correlating with the improvement in dermal and hepatic GVHD. Based on the laboratory findings and analysis of magnetic resonance images, she was diagnosed as having bone marrow infarction. The cause of the bone marrow infarction was thought to be acute GVHD-related microangiopathy.

Adult↗

PubMed1998

Myosin II activation promotes neurite retraction during the action of Rho and Rho-kinase.

BACKGROUND: The Rho small GTPase regulates myosin II activity through the phosphorylation of the myosin light chain (MLC) by activating Rho-kinase, which is a target of Rho. Several lines of evidence point to an important role of Rho in the action of lysophosphatidic acid (LPA) and thrombin in provoking neurite retraction in N1E-115 neuroblastoma cells. RESULTS: Here we examined whether Rho-kinase and myosin II are involved in neurite retraction in N1E-115 cells. We showed that the expression of constitutively active forms of Rho-kinase induced neurite retraction in NIE-115 cells and MLC phosphorylation in NIH 3T3 cells, whereas the expression of dominant negative forms of Rho-kinase inhibited the LPA-induced neurite retraction in N1E-115 cells and the serum-induced MLC phosphorylation in NIH 3T3 cells. The expression of mutant MLCT18D,S19D (substitution of Thr and Ser by Asp), which is known to lead to the activation of myosin ATPase and a conformational change of myosin II when reconstituted with myosin heavy chains in vitro, also promoted neurite retraction. CONCLUSION: These results indicate that Rho-kinase is involved in the LPA-induced neurite retraction downstream of Rho, and that myosin II activation promotes neurite retraction downstream of Rho and Rho-kinase.

3T3 Cells↗

PubMed1998

A novel antibody directed against a three-dimensional configuration of a 95-kDa protein in patients with autoimmune hepatic diseases.

Sera from patients with primary biliary cirrhosis recognize various cellular components, such as mitochondria, centromere, nuclear envelope, and multiple nuclear dot antigens. There also appears to be a novel antibody reacting with a particular protein in these sera. The presence of this antibody was investigated by double immunodiffusion using rat liver cytoplasmic antigens, by immunoprecipitation of [35S]-methionine labelled HeLa cell extracts, and by immunoblot using disrupted HeLa cell extracts. Test sera were obtained from 491 patients with various liver diseases. Nine of the 491 sera were found to react with a 95-kDa protein as determined by immunoprecipitation of [35S]-methionine labelled HeLa cell extracts and by double immunodiffusion using a rat liver microsomal preparation. However, these same nine sera showed no reaction in the immunoblot assay. On the basis of its molecular mass and its presence in the cytoplasmic fraction, this antigen was named p95 C. This anti-p95 C antibody was detected in six of 50 (12%) sera from patients with primary biliary cirrhosis, and in three of 31 (9.7%) sera from patients with autoimmune hepatitis, but not in any of the remaining 410 sera obtained from patients with other hepatic diseases. It is concluded that anti-p95 C antibody reacts primarily with the native form of the 95-kDa protein, and represents another possible analyte for diagnosing autoimmune liver diseases.

Aged↗

PubMed1998

Evaluation of Mini Mental State Examination and Brief Psychiatric Rating Scale on aged schizophrenic patients.

Mini Mental State Examination (MMSE), Brief Psychiatric Rating Scale (BPRS) and subscales of the BPRS were performed on 73 elderly inpatients (mean age: 67.9 years; standard deviation: 7.2; range: 60-89) diagnosed with DSM-III-R chronic schizophrenia. Forty of the subjects were men and 33 were women. A significant negative correlation was observed between MMSE and the age, factor negative, factor depressive, and total score of BPRS. We believe, however, that it is relatively sufficient to screen for demented illness of schizophrenics using MMSE when considering the age and the psychiatric symptoms (especially negative or depressive symptoms ). Forty-eight (66%) of the 73 patients were categorized as 'demented' by MMSE. These results suggest that the aged inpatients with schizophrenia in a hospital showed certain kinds of cognitive deficits (including senile dementia) more frequently than the general population.

Aged↗

PubMed1998

Blockade of neuropsin, a serine protease, ameliorates kindling epilepsy.

The behavioural and electrographical abnormalities associated with seizures in epileptic (kindled) mice correspond with those of human epilepsy. In kindled mice, neuropsin was markedly increased in the hippocampus and cerebral cortices. A single intraventricular injection of monoclonal antibodies specific to neuropsin reduced or eliminated the epileptic pattern noted on electroencephalograms and, as a result markedly inhibited the progression of kindling. Therefore, neuropsin appears to be a key protein controlling pathogenic events in the hippocampus, and thus neuropsin inhibitors might be useful for treatment of epilepsy.

Animals↗

PubMed1998

Expression of neuropsin in the keratinizing epithelial tissue-immunohistochemical analysis of wild-type and nude mice.

Neuropsin is a trypsin-type serine protease that was first cloned from the mouse brain as a factor related to neural plasticity. Subsequent in situ hybridization histochemical analysis indicated a broad localization of its mRNA throughout the whole body, although the details remain obscure. In this study, we showed that neuropsin immunoreactivity is localized in the keratinized stratified epithelia of the mouse epidermis, hair, tongue, palate, nasal cavity, pharynges, esophagus, and forestomach. In the skin and mucous membranes, neuropsin immunoreactivity was found in the stratum spinosum and the stratum granulosum. The immunoreactivity in the former sublayer was mainly present in the cytoplasm, but that in the latter sublayer was exclusively present in the intercellular space or on the outer surface of the cell membrane and thus exhibited a lamellar-like peripheral distribution. During development, the appearance of neuropsin immunoreactivity in the various epithelia was found at embryonic days 14.5-15.5, prior to formation of the stratum corneum. More extensive expression of neuropsin immunoreactivity was found in the nude mouse skin and mucous membranes than in wild-type mice. Because the nude mouse is characterized by genetic impairment of keratinization, such abnormal neuropsin expression might be caused or affected by this impairment. Therefore, neuropsin, an extracellular serine protease, is suggested to be involved in keratinization in the stratified epithelia.

Animals↗

PubMed1998

Effect of xenon on central nervous system electrical activity during sevoflurane anaesthesia in cats: comparison with nitrous oxide.

We have compared the effects of xenon and nitrous oxide on central nervous system (CNS) electrical activity during sevoflurane anaesthesia in cats by recording the electroencephalogram (EEG), multi-unit activity of the midbrain reticular formation (R-MUA) and somatosensory evoked potentials (SEP). Basal anaesthesia with 2% and 5% sevoflurane was used. With 2% sevoflurane, 70% xenon initially produced rhythmic slow waves which were followed by bursts of high-amplitude sharp waves interrupted by low amplitude slow waves on the EEG. Xenon induced an initial increase, followed by a decrease in R-MUA. Nitrous oxide 70% decreased the amplitude of the EEG activity which was associated with an increase in R-MUA. Xenon suppressed the amplitude of both the initial positive and negative deflections of the SEP to a greater extent than nitrous oxide. With 5% sevoflurane anaesthesia, both anaesthetics increased the frequency of spikes on the EEG and facilitated R-MUA. These findings indicate that xenon has a stimulatory action on CNS background activity and a suppressive action on CNS reactive capability which is more potent than that of nitrous oxide.

Anesthetics, Combined↗

PubMed1998

Substrate specificity of pepstatin-insensitive carboxyl proteinase from Bacillus coagulans J-4.

Bacillus coagulans J-4 carboxyl proteinase, designated as J-4, is characterized as alcohol-resistant and insensitive to aspartic proteinase inhibitors such as pepstatin, diazoacetyl-DL-norleucinemetylester, and 1,2-epoxy-3-(p-nitrophenoxy)propane. Here, its substrate specificity was elucidated by using two series of chromogenic substrates, Lys-Pro-Ala-Lys-Phe*Nph (p-nitrophenylalanine:* is cleavage site)-Arg-Leu (XVI) and Lys-Pro-Ile-Glu-Phe*Nph-Arg-Leu (RS6), in which the amino acid residues at positions P5-P2, P2', and P3' were systematically substituted. Kinetic parameters were determined for both sets of peptides. J-4 was shown to hydrolyze Lys-Pro-Ala-Ala-Phe-Nph-Arg-Leu most effectively among the XVI series. The kinetic parameters of this peptide were Km = 20.0 +/- 3.24 microM, kcat = 15.4 +/- 0.71 s-1, and kcat/Km = 0.769 +/- 0.128 microM-1.s-1. Among the RS6 series, Lys-Pro-Ile-Pro-Phe-Nph-Arg-Leu was hydrolyzed most effectively. The kinetic parameters of this peptide were Km = 13.7 +/- 1.30 microM, kcat = 9.65 +/- 0.38 s-1, and kcat/Km = 0.704 +/- 0.072 microM-1.s-1. These systematic analyses revealed that J-4 had a unique preference for the P2 position: J-4 preferentially hydrolyzed peptides having an Ala or Pro residue in the P2 position. Other carboxyl proteinases preferred peptides having hydrophobic and bulky amino acid residue such as Leu in the P2 position. Thus, J-4 was found to differ considerably in substrate specificity from the other carboxyl proteinases reported so far.

Amino Acid Sequence↗

PubMed1998

Isolation and characterization of a cDNA clone of UDP-galactose: flavonoid 3-O-galactosyltransferase (UF3GaT) expressed in Vigna mungo seedlings.

Four cDNA clones were isolated from Vigna mungo seedlings by the screening with cDNA encoding UDP-glucose:flavonoid 3-O-glucosyltransferase (UF3GT) of Antirrhinum majus as a probe; the product of the gene corresponding to one cDNA was more highly expressed in the first simple leaves than in stems. Nucleotide sequence analysis revealed 1,691 bp (including 326 bp non-reading) containing an open reading frame of 455 amino acids. The deduced amino acid sequence showed 42% and 23% identity with those of A. majus UDP-glucose:flavonoid 3-O-glucosyltransferase (UF3GT) and Petunia hybrida UDP-rhamnose:anthocyanidin 3-O-glucoside rhamnosyltransferase (RT), respectively. One region of the cDNA (amino acids 325 to 387) showed similarity to ceramide UDP-galactosyltransferases of mice, rats and humans. A crude extract from Escherichia coli, in which the protein was expressed from the cDNA, showed high UF3GaT activity but low UF3GT activity, and was similar in K(m), optimal pH and substrate specificity to UF3GaT from V. mungo. We conclude that we have obtained UDP-galactose:flavonoid 3-O-galactosyltransferase (UF3GaT) cDNA from V. mungo.

Amino Acid Sequence↗