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M Shibata

Publications and source records attributed to M Shibata.

At least 19 recordsLinked to original sources
PubMed1992

Positive regulation of mu-calpain action by polyphosphoinositides.

Whether calcium is the only major intracellular activator of calpain has not yet been established. Here we demonstrate that polyphosphoinositides may play critical roles in the activation process of mu-calpain. Experiments with purified enzyme, substrate (fodrin), and phospholipids show that only polyphosphoinositides but not other lipids significantly promote calpain action in the physiological intracellular calcium range of 10(-7) to 10(-6) M. The effect of polyphosphoinositide is exerted through both a reduction in the calcium concentration required for calpain autolysis and an increase in the Vmax of the proteolytic reaction. Neomycin, a polyphosphoinositide-binding antibiotic, inhibits both polyphosphoinositide-assisted proteolysis in test tubes and calcium-induced calpain activation coupled with substrate proteolysis in intact cells. This implies that the presence of polyphosphoinositides may actually be a prerequisite for calpain activation inside cells.

Amino Acid Sequence↗
PubMed1992

Hepatitis C virus infection in hepatocellular carcinoma. Detection of plus-strand and minus-strand viral RNA.

BACKGROUND: Although serum antibody to hepatitis C virus (anti-HCV) is found in many patients with hepatocellular carcinoma, the actual roles of HCV in carcinogenesis are unknown. METHODS: With reverse transcription followed by the polymerase chain reaction (RT-PCR), HCV RNA was examined in the sera and liver tissues of 16 patients with hepatocellular carcinoma who did not have hepatitis B virus markers, 13 of whom had anti-HCV. RESULTS: In the 13 patients with anti-HCV, the HCV genomic plus-strand RNA was detected more frequently in noncancerous tissues (8 patients, 61.5%) and in sera (6 patients, 46.2%) than in cancerous tissues (3 patients, 23.1%). No viral RNA was found in either sera or tissues in the three patients without anti-HCV. By using a sense primer for the RT in the RT-PCR assay, amplification was attempted of a putative complementary minus-strand RNA that is believed to reflect viral replication in the eight patients with the plus-strand RNA. The minus-strand RNA was found in the noncancerous tissues of six patients; it was not detected in the cancerous tissues. CONCLUSIONS: These results suggest that HCV can infect and replicate predominantly in noncancerous cells but rarely in tumor cells.

Aged↗
PubMed1992

Cloning of ASH, a ubiquitous protein composed of one Src homology region (SH) 2 and two SH3 domains, from human and rat cDNA libraries.

The protein ASH (for abundant Src homology), composed of one Src homology region (SH) 2 and two SH3 domains, was cloned by screening human and rat cDNA libraries with an oligonucleotide probe directed to a consensus sequence of the SH2 domains. The rat-derived ASH peptide was comprised of 217 amino acids with a molecular mass of 25-28 kDa and was found to be ubiquitous in rat tissues. A human cDNA clone was also found to code for part of the same protein, suggesting that ASH is common to human and rat. The amino acid sequence of ASH was strikingly similar to Sem-5, the product of a nematode cell-signaling gene, and ASH is most probably a mammalian homologue of Sem-5. ASH bound in vitro to phosphotyrosine-containing proteins, including activated epidermal growth factor receptor, the ASH SH2 domain being responsible for the binding. Induced expression of an antisense ASH cDNA led to a reduction in cell growth. Considering these observations and the structural homology to Sem-5, ASH is likely to function as a ubiquitous signal transducer, possibly resembling Sem-5, which communicates between a receptor protein tyrosine kinase and a Ras protein.

Adaptor Proteins, Signal Transducing↗
PubMed1992

Detection and quantification of anti-Ki antibodies by enzyme-linked immunosorbent assay using recombinant Ki antigen.

OBJECTIVE: To establish an enzyme-linked immunosorbent assay (ELISA) for detecting anti-Ki antibody, using a bovine recombinant Ki antigen, and studying its specificity. METHODS: Sera from 220 patients with various connective tissue diseases were screened, and a prospective study of fluctuations in anti-Ki antibody and clinical course of a woman with systemic lupus erythematosus (SLE) was analyzed, by ELISA: RESULTS: Anti-Ki antibodies were present in 18.9% of patients with SLE. The titer of anti-Ki antibody in the woman with SLE rose before the onset of pericarditis and pleuritis in this longitudinal study. CONCLUSION: ELISA using a recombinant Ki antigen is useful for the diagnosis of SLE, and it might be useful in estimating disease activity in patients with SLE.

Animals↗
PubMed1992

Detection of hepatitis C virus by polymerase chain reaction and response to interferon-alpha therapy: relationship to genotypes of hepatitis C virus.

To investigate the relationship between genotypes of hepatitis C virus and response to interferon-alpha therapy, hepatitis C virus RNA was assayed by polymerase chain reaction with three sets of primers and probes in 70 patients with non-A, non-B chronic hepatitis who received interferon-alpha. Twenty-four patients sustained long-term remissions (complete responders). Polymerase chain reaction for 5'-terminal noncoding region detected hepatitis C virus RNA in 94.3% (66 of 70) of the patients. Polymerase chain reaction for nonstructural region 3, in which primers and a probe were synthesized to be identical to hepatitis C virus-J, detected hepatitis C virus RNA in 40 patients. Polymerase chain reaction for nonstructural region 5-in which sequences of primers and a probe were derived from hepatitis C virus-K2, a genotype different from hepatitis C virus-J--detected hepatitis C virus RNA in 17 patients. Only one patient was positive on both nonstructural region 3 and nonstructural region 5 polymerase chain reaction. Nucleotide sequence of clones obtained from 5' terminal noncoding region polymerase chain reaction products of two patients positive on polymerase chain reaction for nonstructural region 3 and negative on polymerase chain reaction for nonstructural region 5 (group 1) corresponded to that of the hepatitis C virus-J group, and those of clones from two patients negative on polymerase chain reaction for nonstructural region 3 and positive on polymerase chain reaction for nonstructural region 5 (group 2) corresponded to that of hepatitis C virus-K2.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Two different protein kinases act on a different time schedule as glial filament kinases during mitosis.

Glial fibrillary acidic protein (GFAP) is a component of glial filaments specific to astroglia. We now report the spatial and temporal distributions of four phosphorylated sites in the GFAP molecule during mitosis of astroglial cells, determined by antibodies which can distinguish phosphorylated epitopes from non-phosphorylated-epitopes. Immunofluorescence microscopy showed that the Ser8 residues in the entire cytoplasmic glial filament system are initially phosphorylated when the cells enter mitosis. In cytokinesis, the phosphoSer8 residues become dephosphorylated, whereas Thr7, Ser13 and Ser34 in glial filaments at the cleavage furrow become the preferred sites of phosphorylation. The cdc2 kinase purified from mitotic cells can phosphorylate GFAP at Ser8 but not at Thr7, Ser13 or Ser34, in vitro. These results suggest that cdc2 kinase acts as a glial filament kinase only at the G2-M phase transition while other glial filament kinases are probably activated at the cleavage furrow before final separation of the daughter cells.

Amino Acid Sequence↗
PubMed1992

Correlation between detection of anti-viral antibody and histopathological disease activity in an epidemic of hepatitis C.

There was an epidemic of non-A non-B hepatitis in a small area of a town in the central part of Japan, which began with an outbreak of several patients in 1981 and then spread extensively with the result that about one third of the inhabitants showed abnormality in serum liver function tests at the health check performed in 1985. We determined histological diagnoses on that occasion for 167 individuals of the abnormal population and recently assayed antibodies against hepatitis C virus (HCV) for most of their sera left available. Histologically, chronic active hepatitis (CAH) was the major pattern, accounting for 59.3% (99 cases) of the total. Others were chronic persistent hepatitis (CPH) (13.2%), chronic lobular hepatitis (CLH) (16.2%), liver cirrhosis (LC) (6.6%) and fatty liver (4.8%). In the serological studies, the newly developed system to detect antibodies against the viral core protein p 22 was found to be much more sensitive than the conventional system to detect anti C 100-3 antibodies. By using these two methods in combination, we found that 82% were antibody-positive, indicating strong implication of HCV in this epidemic. This was further supported by direct detection of the viral genome in patients' sera by polymerase chain reaction following reverse transcription. We further found a strong correlation between the histological inflammatory activity and the antibody prevalence, since nearly all (97.6%) of the CAH cases were antibody-positive by at least either of the antibody assays, while only about 50% were positive in the less active cases such as CPH and CLH.

Base Sequence↗
PubMed1992

The divergent actions of volatile anaesthetics on background neuronal activity and reactive capability in the central nervous system in cats.

The effects of halothane, isoflurane, and enflurane on background neuronal activity and reactive capability in the central nervous system were studied in cats. The background neuronal activity was assessed by midbrain reticular cell firing, which was measured by the method of multi-unit activity, and the EEG in the cortex, amygdala, and hippocampus. The reactive capability was assessed by evoked responses in the visual neuronal pathway. All anaesthetics studied suppressed reticular cell firing in a dose-dependent manner, and the suppression by halothane (43.8 +/- 10.3% of control, mean +/- SD) was less than isoflurane (66.5 +/- 5.8%, P < 0.01) and enflurane (73.1 +/- 8.8%, P < 0.05) at 1 MAC. Spontaneous EEG spikes developed at 4.8% isoflurane and 3.6% enflurane anaesthesia. Phasic activation of reticular cell firing was associated with EEG spikes during isoflurane and enflurane anaesthesia, and the activation during enflurane anaesthesia was greater than during isoflurane anaesthesia (P < 0.01). Photic stimulation provoked EEG spikes and repetitive stimulation induced seizure activity only at 3.6% enflurane anaesthesia. Halothane and isoflurane suppressed stimulation induced responses in the visual neuronal pathway. The amplitudes of N1 in visual cortical evoked responses induced by photic stimulation were suppressed to 70.1 +/- 24.5% of control at 2.4% halothane and 39.3 +/- 27.3% at 4.8% isoflurane. Enflurane, at 3.6%, augmented the evoked response induced by photic stimulation (398.4 +/- 83.0% of control in the amplitude of N1). These results indicate that all the agents studied had suppressive actions on background neuronal activity in the order halothane < isoflurane = enflurane. The effects on reactive capability were divergent among agents, e.g., enflurane enhanced, halothane suppressed, and the actions of isoflurane were intermediate. We conclude that the anaesthetic effects on background activity and on reactive capability are divergent and that suppression of reactive capability is a factor in determining the ease of clinical application of the anaesthetics.

Amygdala↗
PubMed1992

Quantitation of cytomegalovirus DNA in lung tissue of bone marrow transplant recipients.

Five bone marrow transplant recipients who died of respiratory failure were retrospectively analyzed with polymerase chain reaction (PCR) assay for pulmonary cytomegalovirus (CMV) infection. Two patients had CMV interstitial pneumonitis according to the virus isolation and the histologic and immunofluorescent examinations of the lungs, while the other three patients had non-CMV diseases (ie, idiopathic interstitial pneumonitis, pulmonary aspergillosis, or Streptococcus mitis septicemia). Cytomegalovirus DNA was amplified from the postmortem lung tissue with PCR. The PCR assay showed apparent PCR signals specific to CMV DNA in the two patients with CMV pneumonitis. In contrast, CMV DNA was hardly detectable or undetectable in the three patients without CMV disease. With quantitative PCR assay the initial CMV copy number in the lung tissue of the two patients with CMV pneumonitis was more than 10(4) copies/micrograms DNA and was over 1,000-fold more than that of the three patients without CMV pneumonitis. These results show that quantitative PCR assay could be useful as a diagnostic measure for pulmonary CMV infection.

Adolescent↗
PubMed1992

Identification of a 64-kDa protein phosphorylated with glucose in human polymorphonuclear leukocytes in a cell-free system.

We previously reported that a 64-kDa protein (p64) in human polymorphonuclear leukocytes (PMN) was phosphorylated with [gamma-32P]ATP under a micromolar concentration of glucose in a cell-free system. The present paper presents the results of analysis of phosphorylation reaction and the identification of phosphoprotein. The findings that p64 was also phosphorylated with glucose-6-[32P]phosphate and that phosphorylation was inhibited with mannoheptulose suggested that the reaction was mediated by hexokinase. In fact, it was found that [32P]phosphate in glucose-6-[32P]phosphate was incorporated into either p64 or rabbit muscle phosphoglucomutase and that glucose-6-phosphate formation from glucose and ATP was detected in over 100-kDa fraction of PMN cytosol. These results showed that p64 was phosphoglucomutase in PMN and that phosphate incorporation into p64 was a conversion of a phosphate group in glucose-6-phosphate produced by hexokinase. It was further demonstrated by analysis of two-dimensional electrophoresis that p64 phosphorylated with glucose induction was different from another 64-kDa protein phosphorylated by stimulation with formyl-methionyl-leucyl-phenylalanine in vivo.

Cell-Free System↗
PubMed1992

Inorganic alkalizers and acidifiers under conditions of high urinary Na+ or K+ on cell proliferation and two-stage carcinogenesis in the rat bladder.

Effects of alkalizers and acidifiers on bladder cell proliferation and two-stage carcinogenesis were investigated under conditions of high urinary Na+ or K+. Animals were given 0.05% N-butyl-N-(4-hydroxybutyl)nitrosamine in their drinking water for 4 weeks and then received Na3PO4, NaH2PO4, NaCl, NaH2PO4 + NaCl, K3PO4, KH2PO4, KCl, KH2PO4 + KCl or no chemical supplement in the diet from weeks 5 to 8 and from weeks 12 to 20. During weeks 9 to 11, the rats were fed 3% uracil in their diet for acceleration of promotion. Na3PO4 or K3PO4 induced marked natriuresis or kaluresis and alkalinuria associated with strong promoting potential for bladder carcinogenesis. NaH2PO4 induced moderate natriuresis and aciduria and exhibited weak promoting activity. NaH2PO4 + NaCl or KH2PO4 + KCl caused marked increase in the respective cation levels and aciduria with elevation of promotion as compared to NaH2PO4 or KH2PO4 alone. NaCl or KCl induced moderate natriuresis or kaluresis and did not alter urinary pH. NaCl but not KCl also exerted weak promoting activity for bladder carcinogenesis. Increased DNA synthesis after test chemical exposure for 8 weeks and morphological alterations observed by scanning electron microscopy in the bladder epithelium were only quantitatively linked with promoting activity in the Na3PO4 case. With the other treatments no clear correlation between early cell proliferation and promotion potential was apparent. The present results suggest that although elevation in urinary Na+ or K+ level may be an essential factor for promotion of rat bladder carcinogenesis, the action of these cations may depend strongly on urinary alkalinity.

Animals↗
PubMed1992

Nested amplification protocol for the detection of Mycobacterium tuberculosis.

Several methods for rapid diagnosis of tuberculosis have been devised through DNA amplification. However, the chemically strong cell wall of the species, the presumptively low numbers of organisms and their uneven distribution in clinical samples, and the lack of a "gold standard" for diagnosing tuberculosis, have hindered the routine clinical use of this method. In a pediatric patient group, these factors are more perplexing. To circumvent these problems, we made use of nested amplification and developed a standard protocol for extracting DNA from various forms of clinical samples which were suitable to our clinical laboratory. It is our impression that the overall sensitivity, including technical bias accompanying this method, is equal to, or at least greater than, that of culture. Most notably, the rapidity in obtaining results and the simplicity in handling, storage and transfer of samples are the principal advantages of this method.

Arthritis, Infectious↗
PubMed1992

[A case of empyema with subphrenic abscess].

A 75-year-old female was admitted to our hospital with complaints of fever, cough and left hypochondralgia. She had been operated for cholecystectomy ten years ago. Chest roentgenogram indicated bilateral pleural effusion. Tube drainage was done to the left thorax and empyema was caused by Bacteroides fragilis and Escherichia coli (E. coli). Though antibiotic therapy was already being conducted, the left hypochondralgia persisted. A CT scan and MRI demonstrated local subphrenic abscess around the spleen due to E. coli. Tube drainage was conducted to the subphrenic abscess under ultrasound control and and the symptoms disappeared rapidly. The present results show that examination of the abdomen is necessary for empyema with complication of compromised host. The past history of abdominal surgery and disturbance in the biliary tract should also be considered.

Aged↗
PubMed1992

Adenovirus E1A proteins stimulate inositol phospholipid metabolism in PC12 cells.

To study the influence of nuclear oncogenes on inositol phospholipid metabolism, we examined the various parameters of inositol phospholipid metabolism in PC12 cells expressing adenovirus type 12 or adenovirus type 5 E1A. Although the inositol 1,4,5-trisphosphate content was increased only slightly, the diacylglycerol content was 2.4-fold higher in E1A-expressing PC12 cells. Furthermore, we found that the activity of phospholipase C, one of the key enzymes in inositol phospholipid metabolism, was increased at least five- to eightfold. Diacylglycerol kinase activity in the membrane fraction was 10 to 15% of that in parental PC12 cells. Overall protein kinase C activities in E1A-expressing PC12 cells were decreased, but the activity of membrane-bound protein kinase C was significantly increased. These observations clearly indicate that inositol phospholipid metabolism is stimulated in cells producing E1A and suggest that nuclear oncogene E1A has the ability to stimulate inositol phospholipid metabolism.

1-Phosphatidylinositol 4-Kinase↗
PubMed1992

Topical arachidonic acid restores pial arteriolar dilation to hypercapnia of postischemic newborn pig brain.

In the newborn pig, cerebral vasodilator responses to hypercapnia are lost after cerebral ischemia. We examined the effect of topical application of arachidonic acid (30 micrograms/ml, 20 min) to the postischemic piglet brain on subsequent pial arteriolar dilated in response to hypercapnia (10% CO2 ventilation) and topical isoproterenol (10(-6), 10(-7) M). After 20 min cerebral ischemia, pial arterioles did not dilate to hypercapnia but responded to isoproterenol in a fashion similar to before ischemia. Treatment with arachidonic acid after ischemia restored pial arteriolar dilation to hypercapnia. Hypercapnia caused an increase in cortical periarachnoid concentration of 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha) before but not after ischemia. After postischemic treatment with arachidonic acid, the increase in cortical periarachnoid fluid 6-keto-PGF1 alpha during hypercapnia was restored. Therefore, topical application of arachidonic acid to cerebral vessels restores cerebral prostanoid synthesis and pial arteriolar dilation in response to hypercapnia that has been abolished by ischemia.

Administration, Topical↗
PubMed1992

[Effects of FRG-8813, a new type histamine H2-receptor antagonist, on various experimental gastric and duodenal lesions in rats].

We examined the anti-ulcer effects of FRG-8813, a new type histamine H2-receptor antagonist, on various experimental gastric and duodenal lesions in rats. FRG-8813, administered orally, inhibited the formation of lesions dose-dependently in experimental models with the exception of the Shay ulcer model. The anti-ulcer potency of FRG-8813 was 4 approximately 10 times greater than that of cimetidine when the ED50 values of both compounds were compared. Famotidine and cimetidine inhibited lesion formation at higher doses than the anti-secretory doses. The anti-ulcer action of FRG-8813, however, appeared at even lower doses than those of anti-secretory action. These results suggest that FRG-8813 is able to prevent lesion formation with anti-secretory action plus other mechanisms unlike typical histamine H2-receptor antagonists.

Acetamides↗
PubMed1992

[Effects of FRG-8813, a new-type histamine H2-receptor antagonist, on the healing of gastric and duodenal ulcer in rats and spontaneously ulcerative mice].

We examined the anti-ulcer effects of FRG-8813, a new-type histamine H2-receptor antagonist, in chronic ulcer models of rats and mice (W/WV). FRG-8813, given orally twice a day for 7 days, accelerated the healing of gastric or duodenal ulcer induced by acetic acid injection or application at the non-antisecretory doses (0.3 approximately 3 mg/kg). Administration of FRG-8813 to rats with ulcers increased the amounts of mucus in the gastric mucosa. These actions of FRG-8813 were more potent than those of famotidine or cimetidine. In W/WV mice, several ulcers spontaneously developed on gastric mucosa during the 8 weeks after the birth. The ulcers were aggravated by several unknown factors after the ulcer generation in W/WV mice. The aggravation of ulcers was inhibited by the 4-week administration of FRG-8813 with diet at the dose of 1 or 10 mg/kg/day, but was not inhibited by cimetidine at the dose of 100 mg/kg/day. From these results, we suggest that FRG-8813 is able to accelerate the healing of ulcers by antisecretory plus increasing actions on the integrity of the gastric mucosal defense mechanisms; therefore FRG-8813 is expected to be a useful drug for the treatment of gastric or duodenal ulcers in humans.

Acetamides↗