Biomedical subjects

Y Shirai

Publications and source records attributed to Y Shirai.

At least 199 records · Page 11Linked to original sources

PubMed1993

Fusion of dioleoylphosphatidylcholine vesicles induced by an amphiphilic cationic peptide and oligophosphates at neutral pH.

Peptide E5 is an analogue of the fusion peptide of influenza virus hemagglutinin and K5 is a cationic peptide which has an arrangement of electric charges complementary to that of E5. We reported that a stoichiometric mixture of E5 and K5 caused fusion of large unilamellar vesicles (LUV) of neutral phospholipids (Murata, M., Kagiwada, S., Takahashi, S. and Ohnishi, S. (1991) J. Biol. Chem. 266, 14353-14358). K5 caused fusion of LUV composed of dioleoylphosphatidylcholine (DOPC) at pH > 10, but not at neutral pH. In the presence of oligophosphates, such as 1 mM ATP, GTP, or polyphosphate, K5 caused rapid and efficient fusion of DOPC LUV at neutral pH without hydrolysis of oligophosphate groups, but another anions such as citrate, acetate, AMP, phosphate, or EDTA were ineffective. The peptide/oligophosphate-induced fusion behaviors have been investigated by a fluorescence resonance energy transfer assay for lipid mixing of LUV and negative staining electron microscopy. At higher ionic strengths ( > 0.3 M KCl) or in the presence of 5.0 mM MgCl2, the fusion was inhibited. Even at the inhibitory conditions, the association of K5 with lipid vesicles at neutral pH was directly confirmed by the Ficoll gradient assay method and by blue shifts of the tryptophan fluorescence of the peptide. A nonhydrolyzable GTP analogue, GTP gamma S, also induced fusion. These observations suggested that the electrostatic interactions between the positive and negative charges of K5 and oligophosphate, respectively, induced complex formation, triggering membrane fusion.

Adenosine Triphosphate↗

PubMed1993

Increase in [3H]cAMP binding sites and decrease in Gi alpha and Go alpha immunoreactivities in left temporal cortices from patients with schizophrenia.

To search for possible alterations in second messenger systems in the temporal cortex (Brodmann's area 22) of patients with schizophrenia, we measured the binding activities of [3H]adenosine 3',5'-cyclic monophosphate ([3H]cAMP) and [3H]4 beta-phorbol 12,13-dibutyrate ([3H]PDBu) which can label the regulatory subunit of cAMP-dependent protein kinase (protein kinase A) and the regulatory domain of Ca2+/phospholipid-dependent protein kinase (protein kinase C), respectively. We also immunoquantified the variable subunits of guanine nucleotide binding proteins (G-proteins), using specific polyclonal antisera against Gs alpha, Gi alpha and Go alpha. Brains were obtained at autopsy on 10 patients with schizophrenia and 10 age-matched control subjects. Representative Scatchard plots for specific [3H]cAMP bindings to the soluble fraction consisted of a single component with high affinity (Kd = 2.36 nM, Bmax = 737 fmol/mg protein). Among the tested adenyl and guanyl nucleotides, or neuroleptics, cAMP alone potently inhibited the binding (Ki = 4.95 nM). The binding sites for [3H]cAMP were discretely localized, and were in the order of: cerebral cortex = hypothalamus = amygdala > hippocampus = neostriatum = thalamus = nucleus accumbens > globus pallidus = cerebellum. Specific [3H]cAMP bindings to the soluble fractions were about 30% greater in the left temporal cortices of schizophrenic patients, as compared to findings in the right side of the patients and the left side of the control subjects, no control brain showed this asymmetry. The specific [3H]PDBu binding in schizophrenic and control groups did not change.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

Percutaneous transhepatic cholecystostomy for acute acalculous cholecystitis.

The effectiveness and long-term results of percutaneous cholecystostomy for acute acalculous cholecystitis are evaluated. Fifteen patients with acute acalculous cholecystitis were treated prospectively by this procedure, using a pigtail catheter successfully placed under ultrasonographic and fluoroscopic guidance. Prompt relief of the signs and symptoms of cholecystitis was achieved in 14 patients. One required emergency cholecystectomy for uncontrolled bleeding after drainage. Another patient underwent prophylactic cholecystectomy before further chemotherapy for leukaemia. The remaining 13 patients required no further surgery. Morbidity and mortality rates were 13 per cent and nil respectively. Long-term follow-up showed no recurrence of cholecystitis after removal of the catheter. Percutaneous cholecystostomy is a safe, effective and usually definitive procedure for the treatment of acute acalculous cholecystitis.

Acute Disease↗

PubMed1993

A pharmacological analysis of prostaglandin E1 on portal blood flow after partial hepatectomy in rats.

Portal venous flow (PVF) and portal venous pressure (PVP) were examined after the jugular or portal injection of Prostaglandin E1 (PGE) in rats partially hepatectomized by either 40% or 66%. In the 66% hepatectomized animals, the jugular injection of PGE at 5.0 micrograms/kg/min produced an increase in PVF concomitant with a fall in systemic arterial pressure (SAP), while PVP remained unchanged. The portal injection of PGE at 0.5 micrograms/kg/min increased PVF to a level equivalent to that evoked by the jugular injection of 5.0 micrograms/kg/min PGE, without any change in SAP. PVP was reduced synchronistically with an increase in PVF. The PVF response to a portal injection of PGE at 0.5 micrograms/kg/min was not reproduced in liver intact rats. These results suggest that PGE is potent in increasing PVF in the partially resected condition of the liver and that the portal vascular bed is involved in this response.

Alprostadil↗

PubMed1993

Differential changes in serotonin 5-HT1A and 5-HT2 receptor binding in patients with chronic schizophrenia.

Serotonin 5-HT1A and 5-HT2 receptors were examined in the postmortem brains of controls and patients with chronic schizophrenia. In the prefrontal cortex from patients with schizophrenia, 5-HT1A receptor binding was increased, while 5-HT2 receptor binding was decreased, when compared to controls. The increased 5-HT1A receptor binding or the decreased 5-HT2 receptor binding was observed in both the patients who had been medicated with neuroleptics at time of death and those who had not, at least 2 months prior to death. Thus, abnormalities of 5-HT receptor subtypes seem to exist in the brains of patients with chronic schizophrenia. 5-HT related agents might be beneficial for the treatment of schizophrenia.

Chronic Disease↗

PubMed1993

Specificity of amphiphilic anionic peptides for fusion of phospholipid vesicles.

We have synthesized five amphiphilic anionic peptides derived from E5 peptide [Murata, M., Takahashi, S., Kagiwada, S., Suzuki, A., Ohnishi, S. 1992. Biochemistry 31:1986-1992. E5NN and E5CC are duplications of the N-terminal and the C-terminal halves of E5, respectively, and E5CN is an inversion of the N- and the C-terminal halves. E5P contains a Pro residue in the center of E5 and E8 has 8 Glu residues and 9 Leu residues. We studied fusion of dioleoylphosphatidylcholine (DOPC) large unilamellar vesicles assayed by fluorescent probes. The peptides formed alpha-helical structure with different degrees; E5NN, E5CN, and E8 with high helical content and E5CC and E5P with low helical content. These peptides bound to DOPC vesicles at acidic pH in proportion to the helical content of peptide. The peptides caused leakage of DOPC vesicles which increased with decreasing pH. The leakage was also proportional to the helicity of peptide. Highly helical peptides E5NN, E5CN, and E8 caused hemolysis at acidic pH but not at neutral pH. The fusion activity was also dependent on the helicity of peptides. In fusion induced by an equimolar mixture of E5 analogues and K5 at neutral pH, E8, E5NN, and E5CN were most active but E5CC did not cause fusion. In fusion induced by E5-analogue peptides alone, E5CN was active at acidic pH but not at neutral pH. Other peptides did not cause fusion. Amphiphilic peptides also appear to require other factors to cause fusion.

Amino Acid Sequence↗

PubMed1993

Metastasis of hepatocellular carcinoma to the colon demonstrated by Tc-99m PMT scintigraphy.

A 57-year-old man was found to have a tumor in the ascending colon after hepatic segmentectomy for ruptured hepatocellular carcinoma. Colonoscopy was performed, and metastasis of the hepatocellular carcinoma to the ascending colon was suspected based on the biopsy specimens obtained from the tumor. On hepatobiliary scintigraphy using Tc-99m PMT performed to confirm this diagnosis, Tc-99m PMT was clearly observed to accumulate in the tumor. Thus, the tumor was diagnosed as metastasis of hepatocellular carcinoma.

Carcinoma, Hepatocellular↗

PubMed1993

Molecular cloning of two additional members of the neural visinin-like Ca(2+)-binding protein gene family.

We have isolated a rat cDNA clone encoding a neural visinin-like Ca(2+)-binding protein (NVP), which we designate NVP-1. To identify additional molecular forms of NVP, a rat brain cDNA library was screened for their presence using an NVP-1 cDNA probe under low-stringency hybridization conditions. Two types of cDNA clones encoding structurally related proteins, designated NVP-2 and NVP-3, have been isolated. The deduced amino acid sequences of NVP-2 and NVP-3 are 89.0% and 68.6% identical to that of NVP-1, respectively, and contain consensus sequences for EF-hand Ca(2+)-binding sites. Northern blot analysis shows that NVP-1, NVP-2, and NVP-3 mRNAs are most highly expressed in brain and are differentially expressed in various regions of rat brain. These results suggest that NVP-2 and NVP-3 are additional members of the NVP gene family.

Amino Acid Sequence↗

PubMed1993

Carcinoma of the gallbladder: CT evaluation of lymphatic spread.

PURPOSE: To clarify the computed tomographic (CT) characteristics of positive nodes and to assess the ability of CT to demonstrate lymphatic spread. MATERIALS AND METHODS: CT findings of lymph nodes in 51 patients with histologically proved gallbladder carcinoma were correlated with pathologic findings retrospectively. RESULTS: Thirty-one of 51 patients (61%) had a total of 157 positive nodes, 60 (38%) of which were depicted at CT. A positive node was defined at CT as a soft-tissue mass with an anteroposterior dimension of at least 10 mm that showed ringlike or heterogeneous enhancement. These criteria had a positive predictive value of 75% for cystic nodes, 90% for pericholedochal nodes, 100% for posterosuperior pancreatoduodenal nodes, 100% for retroportal nodes, 88% for right celiac nodes, 100% for hepatic nodes, 100% for superior mesenteric nodes, and 83% for interaortocaval nodes. CONCLUSION: CT does not reliably demonstrate all regional nodes of gallbladder carcinoma, but the criteria of size and pattern of enhancement reliably indicate lymphatic spread, which has an important bearing on disease staging and treatment planning.

Carcinoma↗

PubMed1993

A novel fine granule system for masking bitter taste.

In order to prepare fine granules of sparfloxacin (SPFX), a new quinolone anti-bacterial drug that shows masking of the bitter taste of SPFX and dissolutes at a rapid rate, various film-coated fine granules containing 20% SPFX and 0-52% low-substituted hydroxypropylcellulose(L-HPC) in the cores, were prepared by a spray method. Mixtures of ethylcellulose (EC), hydroxypropylmethylcellulose (HPMC), titanium dioxide and sucrose stearate in weight ratios of X:Y:2:1 (X + Y = 6) were used as film materials. The degree of masking of the bitter taste by water-insoluble film, mainly consisting of EC and HPMC, increased by increasing the content ratio of EC to HPMC and the amount of films, but was also slightly affected by the amount of L-HPC in the cores, which were coated with either EC or EC/HPMC (4/2). On the other hand, the dissolution rate increased with an increased amount of L-HPC in the cores and with a decreasing ratio of EC to HPMC in the films. Increasing the amount of L-HPC in the cores, which induced a considerable expansion of the fine granules owing to their taking up of water from the dissolution medium, resulted in bursting of the film after a short lag time. The bioavailability of the film-coated fine granules containing 20% SPFX and 52% L-HPC in the cores and 10% EC/HPMC (4/2) in the coating film, which masked the bitter taste of SPFX and showed the optimal release characteristics, was equivalent to that of conventional tablets containing 100 mg SPFX in beagle dogs.

Animals↗

PubMed1992

Relationship between gallbladder carcinoma and the segmental type of adenomyomatosis of the gallbladder.

Specimens from 3197 consecutive and unselected cholecystectomies performed during a 6-year period were studied. Adenomyomatosis of the gallbladder was defined as a lesion characterized by a thickened wall that consisted of Rokitansky-Aschoff sinuses surrounded by proliferated fibromuscular tissue. Adenomyomatosis was found in 279 specimens and classified as one of three types: segmental, fundal, or diffuse. Segmental adenomyomatosis was found in 188 specimens; gallbladder cancer (GBC) developed in 12 (6.4%) of the patients with segmental type adenomyomatosis. GBC developed in the mucosa of the fundal compartment distal to the annular stricture of the segmental type adenomyomatosis in all 12 of these patients. Conversely, GBC developed in 93 (3.1%) of the other 3009 patients (those with fundal alone, diffuse, or no adenomyomatosis). The prevalence of GBC in patients with segmental adenomyomatosis was significantly (P less than 0.025) higher than that of patients without segmental adenomyomatosis. Clinicians should be aware that segmental adenomyomatosis often coexists with GBC.

Adenoma↗

PubMed1992

cDNA cloning of a neural visinin-like Ca(2+)-binding protein.

A 21,000-dalton Ca(2+)-binding protein (Walsh, M.P., Valentine, K.A., Ngai, P.K., Carruthers, C.A., and Hollengerg, M.D. (1984) Biochem. J. 224, 117-127) was purified from the rat brain and through the use of oligonucleotide probe based on partial amino acid sequence, cDNA clones were obtained from rat brain cDNA library. The complete amino acid sequence deduced from the cDNA contains 191 residues and has a calculated molecular mass of 22,142 daltons. There are three potential Ca(2+)-binding sites like the EF hands in the sequence. It displays striking sequence homology with visinin and recoverin, retina-specific Ca(2+)-binding proteins. Northern blot analysis revealed that the protein is highly and specifically expressed in the brain.

Amino Acid Sequence↗

PubMed1992

Identification of the regional lymphatic system of the gallbladder by vital staining.

In 21 patients with biliary tract cancer dye was injected into the lymphatic system of the gallbladder to determine the extent of its regional lymph nodes. A volume of 0.1-0.3 ml 1 per cent indigo carmine solution was injected directly into lymphatic vessels of the gallbladder in eight patients and into lymph nodes (cystic node or pericholedochal nodes) in 13 patients during radical surgery for biliary tract cancer. The lymphatic system was visualized in a total of 14 patients. The dye descended around the bile duct, flowed into the cystic node, the pericholedochal nodes and the lymph nodes posterior to the head and neck of the pancreas, and finally reached the interaortocaval nodes adjacent to the left renal vein. The stained lymphatic tissue was regarded as the regional lymphatic system of the gallbladder. These nodes should be completely resected during radical surgery for gallbladder cancer.

Bile Duct Neoplasms↗

PubMed1992

cDNA cloning and tissue distribution of a rat ubiquitin carboxyl-terminal hydrolase PGP9.5.

We have isolated a cDNA clone encoding ubiquitin carboxyl-terminal hydrolase PGP9.5 from a rat brain cDNA library and examined the tissue distribution. The primary structure of the cDNA consists of 856 nucleotides including the entire coding region for 223 amino acids, and the calculated molecular mass is 24,782 Da. The rat PGP9.5 is strikingly homologous to the human PGP9.5, 75.2% of nucleic acids and 95.1% of amino acids being identical. The mRNA of PGP9.5 is most abundant in the rat brain and to a lesser degree in the testis. In other peripheral tissues we tested, the mRNA was undetectable. Western blotting using an anti-rat PGP9.5 antibody revealed the parallel distribution of mRNA and protein in various brain regions and testis. The availability of the rat PGP9.5 clone provides a new approach to examine the function of PGP9.5 and the role that it plays in the pathology of neurodegenerative diseases.

Amino Acid Sequence↗

PubMed1992

Inapparent carcinoma of the gallbladder. An appraisal of a radical second operation after simple cholecystectomy.

This study was designed to investigate issues concerning "inapparent carcinoma" of the gallbladder and the effectiveness of a radical second operation in the treatment of inapparent carcinoma. Ninety-eight patients with inapparent carcinoma were analyzed according to the "pT" category of TNM (tumor, nodes, and metastases) classification. Eighty patients underwent cholecystectomy alone, and 14 patients had a subsequent radical operation. After cholecystectomy alone it was found that (1) Patients with pT1 cancer had a 5-year survival rate (5ysr) of 100%; (2) In patients with pT2, 5ysr was 40%; and (3) Patients with pT3 showed 5ysr of 0%. Results of a radical second operation showed that (1) Patients with pT2 cancer showed a 5ysr of 90%, significantly better (p less than 0.05) than pT2 treated with cholecystectomy alone; (2) There was a prolongation of survival in patients with pT3 or pT4. It was concluded that a radical second operation should be carried out for pT2 or more advanced inapparent carcinoma, whereas follow-up without a second operation is recommended for pT1 cancer without positive margin.

Adult↗

PubMed1992

Radical surgery for gallbladder carcinoma. Long-term results.

The authors' objective was to evaluate the effectiveness of radical surgery with lymph node dissection for gallbladder carcinoma. Long-term results were analyzed in 40 patients in a 5-year study. The authors divided the 40 cases into two groups: 20 without positive nodes and 20 with positive nodes. In the group without positive nodes, one patient who underwent R1 resection died of a recurrence at 1 year 7 months. Seventeen of the 19 patients treated with R0 resection survived more than 5 years. The 5-year survival rate was 85% (17/20). In the group with positive nodes, 9 of the 13 patients treated with R0 resection survived more than 5 years, whereas the seven patients treated with R1 or R2 resection died within 5 years. The 5-year survival rate was 45% (9/20). Patients treated by R0 resection showed a 5-year survival rate of 69% (9/13). Thus we documented the favorable long-term results of radical surgery. R0 resection is a prerequisite for long-term survival. The results justify radical surgery with lymph node dissection.

Aged↗

PubMed1992

Elevated levels of plasma transforming growth factor-beta in patients with hepatocellular carcinoma.

We measured the plasma transforming growth factor-beta (TGF-beta) concentration in 14 patients with human hepatocellular carcinoma (HCC) and 9 age-matched normal subjects using growth inhibition assay of mink lung epithelial cells. The calculated plasma TGF-beta concentration in the patients with HCC was 28.6 +/- 27.9 ng/ml (mean +/- SE), showing significant elevation compared with that in 9 normal subjects (5.3 +/- 3.3 ng/ml, P less than 0.01). In three cases, we could measure plasma TGF-beta levels before and after their treatment for HCC. The plasma TGF-beta levels decreased from 59.0 to 18.2 ng/ml after hepatic resection in one case, and from 24.0 to 10.7 ng/ml and from 12.4 to 3.4 ng/ml after transhepatic arterial embolization in the other two cases. These data indicate that plasma TGF-beta level is elevated in patients with HCC, probably due to release from HCC tissues.

Animals↗

PubMed1992

Early carcinoma of the gallbladder.

OBJECTIVE: To clarify the definition and clinicopathological characteristics of early cancer of the gallbladder. DESIGN: Open study. SETTING: University hospital. SUBJECTS: 78 patients with pathological stage T1a and 11 with pT1b tumours. INTERVENTIONS: Of those with pT1a tumours, 51 were treated by simple, and 27 by radical, cholecystectomy. For those with pT1b tumours the figures were 5 and 11, respectively. RESULTS: There were two recurrences, both in patients with pT1a tumours, histological examination of which had shown tumour present at the surgical margins. There were no cases of neurovascular invasion but only one case of lymphatic invasion that was mild and restricted to the lamina propria in a patient with a pT1b tumour. The outcome in the rest was excellent. CONCLUSION: Most pT1 cancers spread locally. Complete resection results in cure regardless of the scope of the operation done. The main determinant of prognosis is the presence of tumour at the resection margins. All pT1 cancers can therefore be regarded as early cancers of the gallbladder.

Cholecystectomy↗