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Biomedical subjects

Y Shirai

Publications and source records attributed to Y Shirai.

At least 109 records · Page 6Linked to original sources
PubMed1998

Distinct effects of fatty acids on translocation of gamma- and epsilon-subspecies of protein kinase C.

Effects of fatty acids on translocation of the gamma- and epsilon-subspecies of protein kinase C (PKC) in living cells were investigated using their proteins fused with green fluorescent protein (GFP). gamma-PKC-GFP and epsilon-PKC-GFP predominated in the cytoplasm, but only a small amount of gamma-PKC-GFP was found in the nucleus. Except at a high concentration of linoleic acid, all the fatty acids examined induced the translocation of gamma-PKC-GFP from the cytoplasm to the plasma membrane within 30 s with a return to the cytoplasm in 3 min, but they had no effect on gamma-PKC-GFP in the nucleus. Arachidonic and linoleic acids induced slow translocation of epsilon-PKC-GFP from the cytoplasm to the perinuclear region, whereas the other fatty acids (except for palmitic acid) induced rapid translocation to the plasma membrane. The target site of the slower translocation of epsilon-PKC-GFP by arachidonic acid was identified as the Golgi network. The critical concentration of fatty acid that induced translocation varied among the 11 fatty acids tested. In general, a higher concentration was required to induce the translocation of epsilon-PKC-GFP than that of gamma-PKC-GFP, the exceptions being tridecanoic acid, linoleic acid, and arachidonic acid. Furthermore, arachidonic acid and the diacylglycerol analogue (DiC8) had synergistic effects on the translocation of gamma-PKC-GFP. Simultaneous application of arachidonic acid (25 MicroM) and DiC8 (10 microM) elicited a slow, irreversible translocation of gamma-PKC- GFP from the cytoplasm to the plasma membrane after rapid, reversible translocation, but a single application of arachidonic acid or DiC8 at the same concentration induced no translocation. These findings confirm the involvement of fatty acids in the translocation of gamma- and epsilon-PKC, and they also indicate that each subspecies has a specific targeting mechanism that depends on the extracellular signals and that a combination of intracellular activators alters the target site of PKCs.

Animals↗
PubMed1998

Relation of interferon therapy and hepatocellular carcinoma in patients with chronic hepatitis C. Osaka Hepatocellular Carcinoma Prevention Study Group.

BACKGROUND: The effect of interferon therapy on the incidence of hepatocellular carcinoma in chronic hepatitis C is poorly defined. OBJECTIVE: To compare the incidence of hepatocellular carcinoma in interferon-treated patients with chronic hepatitis C to that of historical controls and to examine whether response to therapy is related to incidence of hepatocellular carcinoma in patients with chronic hepatitis C. DESIGN: Retrospective cohort study. SETTING: One university hospital and seven university-affiliated hospitals. PATIENTS: 419 consecutive patients with chronic hepatitis C who started interferon therapy between January 1992 and December 1993 (interferon group) and 144 patients with chronic hepatitis C who had liver biopsy between January 1986 and December 1989 and did not receive interferon (controls). INTERVENTION: Patients in the interferon group received human lymphoblastoid interferon, recombinant interferon-alpha2a, or recombinant interferon-alpha2b for 6 months. MEASUREMENTS: The end point was development of hepatocellular carcinoma on abdominal ultrasonography or computed tomography. Sustained response was defined as persistent normalization of alanine aminotransferase (ALT) levels during interferon therapy and follow-up. Relapse was defined as a normal serum ALT level at the end of treatment with an increase to an abnormal level after cessation of treatment. Nonresponse included all other ALT patterns. RESULTS: Median follow-up in the interferon and control groups was 47.6 and 46.8 months, respectively. During follow-up, hepatocellular carcinoma was found in 28 interferon-treated patients and 19 controls. Cox proportional hazards regression analysis that included all patients revealed that interferon therapy (P=0.041), older age (P=0.003), greater histologic activity (P=0.029), and higher histologic stage (P=0.049) were independent factors associated with the development of hepatocellular carcinoma. The risk ratios for development of hepatocellular carcinoma in patients with sustained response, relapse, and nonresponse were 0.06 (95% CI, 0.01 to 0.46), 0.51 (CI, 0.20 to 1.27), and 0.95 (CI, 0.48 to 1.84), respectively, compared with controls. CONCLUSIONS: The incidence of hepatocellular carcinoma was lower in patients with sustained response to interferon therapy than historical controls and nonresponders. Interferon therapy may decrease the risk for hepatocellular carcinoma in patients with chronic hepatitis C.

Alanine Transaminase↗
PubMed1998

Asymmetrical changes in the fodrin alpha subunit in the superior temporal cortices in schizophrenia.

BACKGROUND: We examined possible abnormalities in neural structural proteins that may underlie morphometric changes reported in the left superior temporal cortices (Brodmann's area 22) of schizophrenics. METHODS: Particulate proteins of the superior temporal cortices taken at autopsy from 11 schizophrenic and 9 control brains were fractionated by gel electrophoresis. Target proteins, identified by reading their amino acid sequences, were immunoquantified using the specific antibody. RESULTS: Amino acid sequences of the 150-kDa proteins on sodium dodecyl sulfate/polyacrylamide gel electrophoresis, which were significantly increased on the left side of schizophrenic superior temporal cortices, revealed that they were proteolytic fragments of the alpha subunit of fodrin, a major cytoskeletal protein underlying the plasma membrane. Immunoquantification using the specific antibodies against alpha and beta subunits of fodrin indicated that there exist concomitant decreases in the full-length 240-kDa form and increases in the 150-kDa form of alpha-fodrin with no changes of the 235-kDa form of beta-fodrin in the left superior temporal cortices of the schizophrenic brains. CONCLUSIONS: The findings may be a possible molecular basis for linking morphometric changes to neurochemical pathophysiology in schizophrenia.

Aged↗
PubMed1998

Small GTP-binding proteins in the brain-corpus cardiacum-corpus allatum complex of the silkworm, Bombyx mori: involvement in the secretion of prothoracicotropic hormone.

At least three GTP-binding proteins (G-proteins), 28, 25, and 21 kDa, were found in the brain-corpus cardiacum-corpus allatum complex (BR-CC-CA) of the silkworm, Bombyx mori. They bound to GTP and GDP specifically among nucleotides tested, indicating that these proteins are small G-proteins. The 25 kDa G-protein showed a cross-reactivity to anti-rab3A antibody, while it did not cross-react with anti-rhoA, rab3B, and anti-ras antibodies. On the other hand, the 28 and 21 kDa G-proteins showed no cross-reactivity to any of those antibodies tested. Immunoblot analysis using the anti-rab3A antibody demonstrated that the 25 kDa G-protein was detected preferentially in the BR-CC-CA, and to some extent in the suboesophageal ganglion, but not in the salivary gland, fat body, prothoracic gland, and oesophagus. These results suggested that the 25 kDa G-protein was a member of the rab family of G-proteins. Furthermore, 1 mM GTP gamma S capable of activating G-proteins induced BR-CC-CA to release PTTH under the conditions that stimulation of the PTTH release with hetero-trimeric G-protein was suppressed. These results indicated that the small G-proteins may possibly contribute to PTTH release in Bombyx mori.

Animals↗
PubMed1998

Bowel perforation caused by silicone drains: a report of two cases.

We recently encountered two patients who suffered bowel perforation due to pressure necrosis caused by an open silicone drain placed in the abdominal cavity during surgery. These perforations healed spontaneously after removal of the drains from the site of perforation. Silicone drains are frequently placed in the abdominal cavity to prevent the collection of fluid or blood following surgery; however, a risk of this complication must be borne in mind. Our review of the English literature revealed eight cases of bowel perforations occurring due to a drainage system; six to closed suction drains, and two to open drainage tubes. Seven of these eight patients underwent repeat laparotomy for peritonitis, while the remaining one, who had a closed suction drain, was managed conservatively following discontinuation of the vacuum. Our experience and the literature review suggest that conservative management may be possible in patients without any signs of generalized peritonitis, although repeat laparotomy is required for those with generalized peritonitis. In conclusion, drains should be placed carefully in the abdominal cavity and removed early after the drainage has decreased.

Aged↗
PubMed1998

A highly polymorphic CA repeat marker at the human tumor necrosis factor alpha (TNFA alpha) locus.

Tumor necrosis factor alpha (TNF alpha) in activated monocytes exerts cytotoxic activity and has a variety of other biological effects. We isolated a polymorphic dinucleotide (CA) repeat sequence from a genomic clone containing the gene located at 6p21.3. High heterozygosity (0.80) makes this polymorphism a useful marker in the genetic study of disorders affecting immunological response and cell differentiation.

Alleles↗
PubMed1998

Immunohistochemical localization of serotonin transporter in normal and colchicine treated rat brain.

Distribution of serotonin transporter (SET) was examined immunohistochemically in the rat brain using two specific polyclonal antibodies raised against oligopeptides corresponding with 15 amino acids of carboxyl terminus and 14 amino acids of amino terminus of rat SET. The distribution and density of SET immunoreactive varicose fibers were quite similar to those of serotonin immunoreactive fibers, however no neuronal cell bodies in the brainstem raphe nuclei was stained in normal rat brain. Electron microscopic study showed that SET immunoreactivity was predominantly localized in the presynaptic terminals. After intraventricular infusion of colchicine, neuronal perikarya of dorsal, median, and pontine raphe nuclei became visible. These results suggest that SET is likely present at the synaptic terminals of serotonergic neurons and such localization may be in good agreement with its pharmacological action which includes reuptake of serotonin at presynaptic nerve terminals.

Animals↗
PubMed1998

Malignant fibrous histiocytoma metastases to the small intestine and colon presenting as an intussusception.

A case of malignant fibrous histiocytoma metastases to the small intestine and colon presenting as an intussusception is described. Although malignant fibrous histiocytoma is the most common soft tissue sarcoma in late adult life, GI involvement has rarely been reported. The review of both our case and eight cases in the English-language literature suggests that GI involvement from malignant fibrous histiocytoma occurs most frequently in the small intestine (six of nine) and that two major clinical manifestations of GI involvement are GI bleeding (five of nine) from ulcerated tumors and intussusception (two of nine) led by polypoid tumors.

Colonic Neoplasms↗
PubMed1998

Three distinct mechanisms for translocation and activation of the delta subspecies of protein kinase C.

We expressed delta subspecies of protein kinase C (delta-PKC) fused with green fluorescent protein (GFP) in CHO-K1 cells and observed the movement of this fusion protein in living cells after three different stimulations. The delta-PKC-GFP fusion protein had enzymological characteristics very similar to those of the native delta-PKC and was present throughout the cytoplasm in CHO-K1 cells. ATP at 1 mM caused a transient translocation of delta-PKC-GFP to the plasma membrane approximately 30 s after the stimulation and a sequent retranslocation to the cytoplasm within 3 min. A tumor-promoting phorbol ester, 12-O-tetradecanoylphorbol 13-acetate (TPA; 1 microM), induced a slower translocation of delta-PKC-GFP, and the translocation was unidirectional. Concomitantly, the kinase activity of delta-PKC-GFP was increased by these two stimulations, when the kinase activity of the immunoprecipitated delta-PKC-GFP was measured in vitro in the absence of PKC activators such as phosphatidylserine and diacylglycerol. Hydrogen peroxide (H2O2; 5 mM) failed to translocate delta-PKC-GFP but increased its kinase activity more than threefold. delta-PKC-GFP was strongly tyrosine phosphorylated when treated with H2O2 but was tyrosine phosphorylated not at all by ATP stimulation and only slightly by TPA treatment. Both TPA and ATP induced the translocation of delta-PKC-GFP even after treatment with H2O2. Simultaneous treatment with TPA and H2O2 further activated delta-PKC-GFP up to more than fivefold. TPA treatment of cells overexpressing delta-PKC-GFP led to an increase in the number of cells in G2/M phase and of dikaryons, while stimulation with H2O2 increased the number of cells in S phase and induced no significant change in cell morphology. These results indicate that at least three different mechanisms are involved in the translocation and activation of delta-PKC.

Adenosine Triphosphate↗
PubMed1998

Subspecies-specific targeting mechanism of protein kinase C.

To clarify the subspecies-specific functions of protein kinase C (PKC), we constructed cDNAs encoding gamma-, epsilon- and delta-PKC fused with green fluorescent protein (GFP). All fusion proteins had enzymological and immunological characteristics similar to those of native PKCs. When expressed in CHO-K1 cells, each fusion protein showed a specific subcellular localization. Their translocations induced by various stimulation were also diverse. For example, ATP translocated gamma-, epsilon- and delta-PKC-GFP in the cytoplasm to the plasma membrane within 30 sec with a return to the cytoplasm in 3 min, whereas TPA induced slow and irreversible translocation of all subspecies to the plasma membrane. Fatty acids also induced the translocation of gamma- and epsilon-PKC-GFP, but the two PKC subspecies showed distinct translocation and sensitivity to various fatty acids. Furthermore, we revealed that the PKC translocation requires neither the kinase activity of PKC nor its association with cytoskeletal proteins such as F-actin. These results indicate that each subspecies has a spatially and temporally different targeting mechanism that depends on the extracellular and intracellular signals, contributing to the subspecies-specific functions of PKC. These remarkable findings also indicate that a system for monitoring the PKC translocation is a powerful tool for investigating the subspecies-specific functions of PKCs and mechanism of its translocation.

Animals↗
PubMed1998

Molecular cloning of cDNA for BRab from the brain of Bombyx mori and biochemical properties of BRab expressed in Escherichia coli.

From a brain cDNA library of Bombyx mori, we cloned cDNA for BRab, which encoded a 202-amino-acid polypeptide sharing 60-80% similarity with rab1 family members. To characterize its biochemical properties, cDNA for BRab was inserted into an expression vector (pGEX2T) and expressed in Escherichia coli as a glutathione S-transferase (GST) fusion protein. The recombinant protein was purified to homogeneity with glutathione S-Sepharose. The purified GST-BRab bound [35S]-GTP gamma S and [3H]-GDP with association constants of 1.5 x 10(6) M-1 and 0.58 x 10(6) M-1, respectively. The binding of [35S]-GTP gamma S was inhibited with GTP and GDP, but with no other nucleotides. The GTP-hydrolysis activity was evaluated to be 5 m mole/min/mole of BRab. In the presence of 6 mM MgCl2, bound [35S]-GTP gamma S and [3H]-GDP were exchanged with GTP gamma S most efficiently. These results suggest that BRab, having a higher affinity for GTP than GDP, converts from the GTP-bound state into the GDP-bound state by intrinsic GTP hydrolysis activity and returns to the GTP-bound state with the exchange of GDP with GTP.

Amino Acid Sequence↗
PubMed1998

Veins of the lumbar spinal ganglia in human adults and fetuses.

To obtain a fundamental knowledge of the morphological relationship between nerve root symptoms and circulatory disorders, the distribution pattern of the veins in the lumbar spinal ganglia from the first to fifth vertebrae was investigated in 5 adult human cadavers (mean age 69.6 years) and 5 human fetuses (mean age 6.6 months). The following results were obtained: 1) In the adults the veins perforating from the outer surface of the fifth lumbar spinal ganglion were smaller in number than those perforating from the first to fourth ganglia. In contrast, in the fetuses the number of such veins was increased in the lower lumbar spinal ganglia. In each of the ganglia, the number of veins emerging through the dorsal side was much higher than the number perforating from the outer surface of the ventral sides. The veins perforating through the outer surface of the ganglion formed weak venous networks (periganglionic venous plexus) surrounding the dorsal ramus of the spinal nerve. 2) The veins communicating with the tributaries from the periganglionic venous plexus were classified into three types. Type 1 veins flowed into the intervertebral veins (the frequency ranged from 9.2 to 18.2 in the adults and from 22.4 to 37.0 in the fetuses). Type 2 veins coursed in the spinal cord along the dorsal root fibers and penetrated the dura mater on the way (the frequency ranged from 0.4 to 4.8 in the adults and from 1.2 to 2.2 in the fetuses). Type 3 veins opened directly into the internal vertebral plexus (the frequency ranged from 0.4 to 1.8 in the adults and from 0 to 0.4 in the fetuses). Type 1 veins were the most frequent among the three types of veins in both adults and fetuses. Few type 3 veins were observed in either group. 3) In the first and second lumbar vertebrae in the adults, three-quarters of each spinal ganglion was situated in the vertebral canal. In the lower lumbar region (L3-L5), three quarters of each spinal ganglion lay on the outside of the vertebral canal. In the fetuses, approximately one half to three-quarters of each lumbar spinal ganglion was located in the vertebral canal.

Aged↗
PubMed1998

Combination of low back pain and previous low back pain and shoulder stiffness in construction employees.

A postal questionnaire for the prevalence of low back pain was studied with relevance to stiffness of that shoulder and a history of low back disorders in construction employees. The percentage of clerical employees with low back pain was 31.3% and of field workers was 30.3%. Odds ratios representing a relative risk factor for low back pain relating to each age group showed 2.35 in the clerical and 2.10 in the field workers at the age of 30-34 years, and 3.34 and 2.58 at the age of 35-39 years, respectively. In the persons with positive previous low back pain, the prevalence rate of low back pain was 52.6% in the clerical, and 50.2% in the field workers. Odds ratios for low back pain relating to previous low back pain significantly exceeded unity for the clerical employees (OR = 9.53) and the field workers (OR = 10.28), compared to those without a history of previous low back pain. The incidence of stiffness of the shoulder was 48.2% in the clerical and 45.2% in the field workers, and the prevalence rate of low back pain among those with stiffness of the shoulder was 68.5% in the clerical and 65.8% in the field workers. Odds ratio were 3.03 in both groups. Among each age group, the prevalence rate of stiffness of the shoulder with low back pain increased gradually to a maximum in the 45-49 age group of 19%, and then dropped. In those with a history of low back pain and/or stiffness of the shoulder, the prevalence of low back pain showed significantly greater value than other risk factors.

Adult↗
PubMed1998

Enlargement of bone tunnels after anterior cruciate ligament reconstruction.

We measured the width of tibial bone tunnels after anterior cruciate ligament (ACL) reconstruction, and investigated the correlation between bone tunnel enlargement and clinical results. Thirty-two patients who had undergone ACL reconstruction with patellar tendons augmented by woven polyester underwent physical and radiographic examinations postoperatively. The interval between surgery and examination ranged from 60 to 91 months with a mean of 68.9 months. The clinical results investigated included the total Lysholm score, the injured-to-uninjured difference in anterior knee laxity from KT-1000 arthrometer measurements, and range of motion. The width of the tibial bone tunnels was increased by a mean of 2.6 +/- 1.5 mm in the antero-posterior view, and by a mean of 2.7 +/- 1.4 mm in the lateral view. Eighteen patients had tunnel enlargements of less than 3 mm, and 14 patients had enlargements of 3 mm or more. The clinical results for patients with tunnel enlargements of less than 3 mm were compared with those for patients with tunnel enlargements of 3 mm or more. However, no significant differences were found between the two groups. We conclude that bone tunnel enlargement does not appear to adversely affect clinical results over the long term.

Adolescent↗
PubMed1998

Early intraperitoneal dissemination after radical resection of unsuspected gallbladder carcinoma following laparoscopic cholecystectomy.

We describe a case of early intraperitoneal dissemination after a radical second operation following laparoscopic cholecystectomy for unsuspected locally advanced carcinoma of the gallbladder. A radical procedure including wedge resection of the gallbladder bed, resection of the extrahepatic bile ducts, and dissection of the regional nodes and interaortocaval nodes was performed 17 days after laparoscopic cholecystectomy in a 60-year-old woman. The final histologic examination revealed a moderately differentiated adenocarcinoma invading perimuscular connective tissue with one positive pericholedochal node (pT2, pN1, pM0). Despite the absence of intraperitoneal dissemination at reexploration, the patient had intraperitoneal dissemination 5 months after the second operation. Insidious intraperitoneal dissemination may decrease the survival rate of locally advanced carcinoma of the gallbladder after laparoscopic cholecystectomy compared with open cholecystectomy. Surgeons should search for unsuspected carcinoma of the gallbladder intraoperatively to avoid implantation metastasis.

Adenocarcinoma↗