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Biomedical subjects

M Shibata

Publications and source records attributed to M Shibata.

At least 397 records · Page 22Linked to original sources
PubMed1994

[Experimental study of peripheral nerve expansion with a tissue expander].

If a peripheral nerve could be elongated by a tissue expander (TE) without apparent damage, the length gained could be used to overcome a nerve gap without recourse to nerve graft. An experimental study was made to investigate whether this method for repairing a nerve gap is feasible. The tissue expander was designed by the authors and the median nerve of rabbits were stretched with TE at the rate of about 1 mm/day. The results showed that when the elongation rate was 18.4%, the motor nerve conduction velocity (MCV) was 67.8% and the myelinated nerve fibres (MNF) was 82.9% of the control nerves. In a further study nerve grafting and nerve expansion for repairing segmental nerve loss were compared with 10 mm defects. 4 months later the MCV, MNF, isometric contraction force (ICF) and muscle wet weight (MWW) were not significantly different between the 2 techniques. But with the 15 mm defects, elongated nerve were inferior to the nerve grafting method.

Animals↗
PubMed1994

[Three phase bone scintigraphy of reflex sympathetic dystrophy and its change with sympathetic blockade].

We examined three phase bone scintigraphy performed at various stages, covering 13 patients with reflex sympathetic dystrophy (RSD) of limbs. In three patients, changes following sympathetic nerve block were examined. In stage-1, radiation count in the affected limbs increased markedly in phases 1 to 3 as compared with the values in healthy limbs. In stage-2, radiation count decreased in phase-1, showed about the same level in phase-2, and maintained an increased level in phase-3. In stage-3, count decreased in phase-1 and 2, and showed about the same level in phase-3. In patients who received a chemical sympathectomy in its early stage, the count was found to have returned to normal level over a short period of time from phase 1 to 3. Three phase bone scintigraphy was considered useful in understanding the pathologic condition of RSD and follow-up evaluation of treatment mainly consisting of sympathetic nerve block.

Adult↗
PubMed1994

[Myocardial infarction in infective endocarditis].

Two patients with chronic valvular heart disease and myocardial infarction were assisted at our hospital. Both of them were febrile and only one had petechiae associated with signs of valvular involvement led to suspicion of infective endocarditis. Although blood cultures were negative, echocardiographic, surgical and anatomopathologic findings were compatible with infective endocarditis. They required cardiac surgery during the acute phase of the infection because they presented progressive hemodynamic deterioration and no satisfactory response to antimicrobial regimen too. One patient died at late follow-up (two weeks after the hospital discharge) and the other survived, but with signs of cardiac failure (class II of NYHA) one year after the procedure.

Adolescent↗
PubMed1993

Phosphorylation of a 62 kd porcine alpha-internexin, a newly identified intermediate filament protein.

A 62 kd protein was purified from the Triton-insoluble fraction of porcine brain white matter. This protein formed 10nm filaments, in vitro. The phosphorylation of the 62 kd protein by cAMP-dependent protein kinase caused electrophoretic mobility to shift to 66 kd on SDS-PAGE and a complete loss of the filament forming ability ensued. Amino acid sequences of four peptide fragments obtained from the 62 kd protein by lysylendopeptidase were identical with that of a 66 kd rat brain alpha-internexin. Amino acid analyses of the phosphopeptide fragment derived from phosphorylated porcine alpha-internexin revealed that the phosphorylation sites by cAMP-dependent protein kinase located in the amino-terminal head domain of this protein. These results strongly suggest that alpha-internexin polymerizes into 10nm filaments in vitro and that phosphorylation of the amino-terminal domain of alpha-internexin controls its polymerizability.

Amino Acid Sequence↗
PubMed1993

Gastric antisecretory effect of FRG-8813, a new histamine H2 receptor antagonist, in rats and dogs.

FRG-8813, a new histamine H2 receptor antagonist, was examined for antisecretory effects and compared with famotidine and cimetidine in rats and dogs. In pylorus-ligated and lumen-perfused rats, FRG-8813 given i.v. reduced basal gastric acid secretion and the acid secretion evoked by histamine, tetragastrin, bethanechol, and 2-deoxy-D-glucose in a dose-dependent manner. The i.v. antisecretory activity of FRG-8813 was equivalent to or slightly less than that of famotidine and the intraduodenal (i.d.) activity was greater than that of cimetidine. The duration of action of FRG-8813 was substantially longer than that of farmotidine and cimetidine for both i.v. and i.d. routes. The i.v. ED40 values for the histamine- and tetragastrin-evoked responses and the i.v. ED30 value for the bethanechol-evoked response were 0.15, 0.09 and 0.43 mg2kg, respectively. In Heidenhain pouch dogs, when the three H2 antagonists were given i.v. or orally, the relative antisecretory potency of the compounds was similar to that in rats. The long-lasting antisecretory effect of FRG-8813 was also observed, and the i.v. ED50 values for histamine-, tetragastrin- and bethanechol-evoked responses were 0.1, 0.24 and 1.0 mg/kg, respectively. Comparison of the parenteral and enteral potencies indicated that FRG-8813 has a lower bioavailability than famotidine and cimetidine in rats and dogs. These data suggest that FRG-8813 has a potent and long-lasting antisecretory effect with a far greater potency than cimetidine and with a slightly lower potency than famotidine.

Acetamides↗
PubMed1993

Ash/Grb-2, a SH2/SH3-containing protein, couples to signaling for mitogenesis and cytoskeletal reorganization by EGF and PDGF.

The Src homology (SH) region 2 binds to phosphorylated tyrosine residues and SH3 domains may interact with cytoskeletal molecules and GTPase-activating proteins for Rho/Rac proteins (the small GTP-binding proteins related to Ras). The recently cloned Ash/Grb-2 protein, a 25-28 kDa molecule composed entirely of SH2 and SH3 domains, is a mammalian homolog of the Caenorhabditis elegans Sem-5 protein, which communicates between a receptor protein tyrosine kinase and a Ras protein. In the present study the function of Ash/Grb-2 was investigated by microinjecting cells with an anti-Ash antibody. The antibody abolished both S phase entry and the reorganization of actin assembly to ruffle formation upon stimulation with epidermal growth factor (EGF) and platelet-derived growth factor (PDGF). On the other hand, anti-Ash antibody had no effect on S phase entry or actin stress fiber formation induced by either serum or lysophosphatidic acid. Since the induction of DNA synthesis, ruffle induction and stress fiber formation involve a function of Ras, Rac activation and Rho activation respectively, the findings strongly suggest that Ash plays a critical role in the signaling of both pathways downstream from growth factor receptors to Ras and Rac. Consistent with this, Ash co-precipitated with EGF receptor from EGF-stimulated cells. Other proteins of approximately 21, 29, 135 and 160 kDa were also detected in the anti-Ash antibody immunoprecipitates, suggesting a role of Ash as a linker molecule in signal transduction downstream of growth factor receptors.

Adaptor Proteins, Signal Transducing↗
PubMed1993

Characterization of a 64-kd protein phosphorylated during chemotactic activation with IL-8 and fMLP of human polymorphonuclear leukocytes. I. Phosphorylation of a 64-kd protein and other proteins.

Interleukin-8 (IL-8) such as LUCT (lung giant cell carcinoma-derived chemotactic protein), NAP (neutrophil activating protein) and MDNCF (monocyte-derived neutrophil chemotactic factor), and formylmethionyl-leucyl-phenylalanine (fMLP) are well-known chemoattractants for human polymorphonuclear leukocytes (PMNs) and are able to stimulate phosphorylation of 64-kd protein (p64) in these leukocytes. To elucidate the molecular mechanism of PMN activation with chemoattractants, we investigated the phosphorylation process of p64 in an intact cell. 32P-Labeled PMNs were stimulated with LUCT/IL-8, fMLP, leukotriene B4, or C5a, and phosphorylated proteins were analyzed by two-dimensional electrophoresis and autoradiography. A marked phosphorylation of p64 was observed after stimulation. A new spot of phosphorylated p64 (pp64) could be detected on the gel stained with Coomassie Brilliant Blue, indicating that the isoelectric point (pI) of p64 shifted from 5.3 to a more acidic pI by the phosphorylation forming pp64. The spot of pp64 was shown to be dephosphorylated to p64 by treatment with calf intestine alkaline phosphatase. Other proteins having molecular masses 82, 66, 58, 55 and 50 kd were also phosphorylated. The fMLP-stimulated phosphorylation was time-dependent and saturated within 5 min. Maximum stimulation was achieved with 10 nM fMLP. Phosphoamino acid analysis revealed phosphorylation of serine residues in pp64. Staurosporine (100 nM) and W-7 (100 microM) significantly inhibited the phosphorylation of p64, but H-7 slightly inhibited it. H-8 and herbimycin A did not effect phosphorylation. Phorbol myristate acetate was found to stimulate significantly. Protein kinase C did not stimulate the phosphorylation. These data suggest that protein kinase C and calmodulin-like protein are indirectly involved in the phosphorylation of p64 during chemoattractant-activation of PMN.

Alkaline Phosphatase↗
PubMed1993

Characterization of a 64-kd protein phosphorylated during chemotactic activation with IL-8 and fMLP of human polymorphonuclear leukocytes. II. Purification and amino acid analysis of phosphorylated 64-kd protein.

Lung giant cell carcinoma-derived chemotactic protein (LUCT)/IL-8 and fMet-Leu-Phe stimulate phosphorylation of a 64-kd protein (p64) in 32P-labeled human polymorphonuclear leukocytes (PMNs). The p64 was purified from cytosol of human PMNs (1.8 x 10(9) cells) by DEAE-Sepharose CL6B column chromatography, hydroxyapatite HPLC, and reverse-phase HPLC. By hydroxyapatite HPLC, p64s were separated and produced two peaks containing both nonphosphorylated and phosphorylated p64. Amino acid composition of each p64 was determined. Each p64 was directly subjected to amino acid sequencing, but the amino acid residue in the amino-terminal of the proteins could not be detected. From the results of amino acid composition and other characters of p64, it is suggested that p64 is identical to l-plastin, which is a leukocyte-specific protein.

Amino Acid Sequence↗
PubMed1993

Quantitative analysis of herpes simplex virus DNA in cerebrospinal fluid of children with herpes simplex encephalitis.

Herpes simplex virus (HSV) DNA in the cerebrospinal fluid (CSF) of children with herpes simplex encephalitis (HSE) was quantified and typed using the polymerase chain reaction (PCR) assay. During the acute phase, HSV-DNA was detected in the CSF of 13 patients with HSE, including 5 neonates. A restriction profile of the PCR products cleaved with the restriction enzymes XhoI and BglII showed that 2 neonatal samples were HSV-2, and the remainder were HSV-1. The amount of HSV-DNA in the initial CSF ranged from 10(2)-10(5) copies/ml. A significantly greater number of HSV-DNA copies was detected in neonates than in older children (mean 3.9 vs. 2.5, log 10 copies/ml p < .05). Except for one patient, the amount of HSV-DNA decreased gradually with acyclovir therapy. These results show that a quantitative PCR assay is applicable not only to the diagnosis of HSE but also for monitoring the response to antiviral drugs.

Adolescent↗
PubMed1993

T-cell receptor V alpha region usage in the cerebrospinal fluid of patients with mumps meningitis.

To investigate clonality of local T cells in viral infections of the central nervous system, the T-cell receptor (TCR) repertoire was evaluated in T cells from the cerebrospinal fluid (CSF) of nine patients with mumps meningitis, using the polymerase chain reaction (PCR) assay. The usage of the variable region of TCR alpha chain gene (V alpha gene) in the CSF was widespread, and an average of 13 out of the 18 V alpha families were expressed. Quantitative PCR analyses showed that the V alpha gene expression was biased toward three or less V alpha families in the CSF of each patient. When compared with peripheral blood T cells, the average percentages of V alpha 11 and V alpha 12 gene expression were significantly higher in the CSF than in the peripheral blood. These results suggested that mumps-specific T lymphocytes with a restricted TCR repertoire are selectively recruited to the central nervous system in mumps meningitis, although polyclonal, probably nonspecific, T-cell populations are present in the CSF.

Adolescent↗
PubMed1993

Detection of human papillomavirus type 2a DNA in verrucae vulgares by electron microscopic in situ hybridization.

Electron microscopic in situ hybridization (EMISH) of common warts (verrucae vulgares) of the hands was performed using a biotinylated human papillomavirus type 2a (HPV-2a) DNA probe and immunogold labelling of ultrathin sections of 2% glutaraldehyde-fixed, Lowicryl K4M-embedded tissues. It was first established that the warts contained HPV-2a DNA by light microscopic in situ hybridization. The HPV-2a probe chiefly labelled cells in the horny, granular and upper spinous layers of the epidermis, and labelling decreased towards the basal cell layer. The gold particles were located precisely on the viral particles in the nuclei of granular cells. The lower limit of detection by EMISH was found to be the keratinocytes of the third cellular layer above the basal cells. These keratinocytes showed evidence of a viral cytopathic effect, suggesting that vegetative DNA replication in infected keratinocytes occurs at least as early as this level of the epidermis.

DNA, Viral↗
PubMed1993

Effects of interferon-alpha on serum hepatitis C virus in patients with chronic hepatitis C.

Interferon is beneficial in some patients with chronic hepatitis C. To assess the efficacy of interferon, we used the polymerase chain reaction (PCR) to measure HCV RNA in serial serum samples from 13 chronic hepatitis C patients who were treated with interferon-alpha. Serum alanine aminotransferase (ALT) values normalized in association with the disappearance of serum HCV RNA in nine cases during the therapy. Serum HCV remained negative after the therapy in the three patients who had no relapse, while serum HCV RNA reappeared in the six patients with elevation of ALT values. The persistence of normal ALT levels appears to be correlated with the clearance of the serum HCV. There were two patients whose ALT became normal immediately after the cessation of interferon. Serum HCV was detectable at the end of treatment when serum ALT was elevated, and thereafter serum HCV disappeared. This result suggests an immunomodulatory effect of interferon in the clearance of HCV in some cases. Furthermore, the semiquantitative PCR assay showed that all five patients in whom ALT values were normal at the end of follow-up without detectable serum HCV genome had lower HCV titers in the pretreatment sera than the other eight patients. The detection of HCV RNA by the PCR assay is useful in determining the efficacy of interferon and its mechanisms.

Adult↗
PubMed1993

Point charge representation of multicenter multipole moments in calculation of electrostatic properties.

Distributed Point Charge Models (PCM) for CO, (H2O)2, and HS-SH molecules have been computed from analytical expressions using multi-center multipole moments. The point charges (set of charges including both atomic and non-atomic positions) exactly reproduce both molecular and segmental multipole moments, thus constituting an accurate representation of the local anisotropy of electrostatic properties. In contrast to other known point charge models, PCM can be used to calculate not only intermolecular, but also intramolecular interactions. Comparison of these results with more accurate calculations demonstrated that PCM can correctly represent both weak and strong (intramolecular) interactions, thus indicating the merit of extending PCM to obtain improved potentials for molecular mechanics and molecular dynamics computational methods.

Carbon Monoxide↗