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Biomedical subjects

T Morimoto

Publications and source records attributed to T Morimoto.

At least 253 records · Page 14Linked to original sources
PubMed1997

Expansive laminoplasty for multilevel cervical OPLL.

Expansive laminoplasty is a new technique for the management of cervical ossification of the posterior longitudinal ligament (OPLL). Twenty patients were followed up for an average 3-year period. Follow-up examinations were performed every 3 months and at 1-year intervals. On lateral radiographs, the average increase in the anteroposterior (AP) diameter of the canal was 42%. Bone fusion was documented on computed tomography (CT) studies 3 months after surgery in 96% of patients. An average 83% of normal range of motion was preserved on long-term follow-up (3 years on average). Postoperative improvement over the same interval increased from an average preoperative Japanese Orthopaedic Association score of 7.9 to 14.1 Expansive laminoplasty as described is safe and has a high fusion rate, while better preserving the normal range of motion.

Constriction, Pathologic↗
PubMed1997

Relationship between duration of rheumatoid arthritis before knee joint surgery and HLA-DRB1 alleles: a retrospective study.

OBJECTIVE: To examine whether genetically determined factors can be used as predictors of requirement for knee joint surgery in the early phase of rheumatoid arthritis (RA). METHODS: We determined HLA-DRB1 alleles in 322 patients with seropositive RA by polymerase chain reaction and allele specific oligonucleotide probe techniques. Patients were classified into 3 groups (S/S, S/N, and N/N) based on their possession of two, one or no susceptibility alleles of RA, respectively. The stage of radiographic change in the knee joint determined using Larsen's standard film was compared to results of genotyping. Duration of RA before joint surgery in the 3 groups was also compared retrospectively. RESULTS: The median number of years to develop to stages I, II, III, and IV and the number of years of disease duration before total knee arthroplasty (TKA) were significantly shorter in the S/S group than in the S/N and N/N groups (p < 0.05). CONCLUSION: TKA was required earlier in the S/S group than in the S/N and N/N groups. This finding will affect planning of surgical management for RA based on anticipated courses.

Adult↗
PubMed1996

Intramedullary gadolinium-DTPA enhancement in a patient with cervical spondylotic myelopathy and an associated vascular lesion. Case report.

Intramedullary enhancement of the cervical spinal cord is rare in chronic compression disease. An accompanying vascular lesion should be considered in such a case. A 59-year-old man presented with severe cervical spondylotic myelopathy. Gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) enhanced magnetic resonance imaging showed intramedullary enhancement at the C5-6 level, which was the most severely compressed level. A right ascending cervical arteriogram demonstrated a spinal arteriovenous fistula (AVF) fed mainly by the C-6 radicular artery and draining from the posterior medullary vein. Surgery was performed to decompress the myelopathy and to obliterate the AVF. Postoperative MR imaging with Gd-DTPA enhancement showed immediate and complete disappearance of the previous enhancement. The intramedullary enhancement presumably resulted from the intraparenchymal hemodynamics due to the AVF.

Journal Article↗
PubMed1996

The Dri 42 gene, whose expression is up-regulated during epithelial differentiation, encodes a novel endoplasmic reticulum resident transmembrane protein.

A search for novel genes that are up-regulated during development and differentiation of the epithelial cells of the intestinal mucosa led us to the isolation of the Dri 42 cDNA clone (Dri, differentially expressed in rat intestine). The nucleotide sequence of the full-length cDNA has shown that it encodes a 35.5-kDa protein with one consensus sequence for N-linked glycosylation and alternating hydrophilic and hydrophobic domains. To determine the intracellular localization of Dri 42 we have raised polyclonal antibodies in hens against a bacterially produced Dri 42-glutathione S-transferase fusion protein. Immunofluorescence detection with these antibodies has shown specific staining of the endoplasmic reticulum (ER) in the relatively undifferentiated fetal rat intestinal cell line FRIC B and in sections of rat small intestine. ER membrane localization of Dri 42 was confirmed by laser confocal microscopy of polarized Madin-Darby canine kidney cells overexpressing a Dri 42-chloramphenicol acetyltransferase (CAT) fusion protein by transfection. Pulse labeling experiments on transiently transfected cells demonstrated that the protein does not acquire Golgi modifications up to 4 h after synthesis, thus indicating that Dri 42 is an ER resident protein. The transmembrane disposition of Dri 42 was studied using in vitro insertion of Dri 42-CAT fusion proteins into microsomal membranes. The fusion proteins consisted of several different lengths of truncated Dri 42 and a reporter protein, CAT, that was linked in-frame after each hydrophobic segment. We found that hydrophobic segments H1, H3, and H5 had a signal/anchor function, and that membrane insertion of Dri 42 was achieved co-translationally by the action of a series of alternating insertion signals and halt transfer signals, resulting in the exposure of both termini of the protein to the cytosolic side. The functional implications of the structure and localization of Dri 42, whose primary sequence does not share significant homology to any previously described protein, are discussed.

Amino Acid Sequence↗
PubMed1996

Temperature-dependent enhancement of proteolysis in C2C12 myotubes in association with the activation of 26S proteasome.

The effect of temperature on protein metabolism of C2C12 myotubes was investigated in order to estimate the potential effect of fever on muscle catabolism. The half-life of long-lived proteins in C2C12 myotubes was significantly (13%) shorter when incubated at 40 degrees C than at 37 degrees. The activities of cathepsins B and L were not significantly different at 37 and 40 degrees C, nor were the levels of the protein and mRNA of the two cathepsins. In contrast, the chymotrypsin-like activity of 26S proteasome was elevated by 53% at 40 degrees C, compared to that at 37 degrees C, although it was not associated with an increase in the levels of the protein and mRNA of proteasome subunits. mRNA levels of calpain and ubiquitin were not affected by temperature. It is concluded that temperature-dependent enhancement of proteolysis in C2C12 myotubes is associated with an increase in 26S proteasome activity.

Animals↗
PubMed1996

Molecular epidemiology of breast cancers in northern and southern Japan: the frequency, clustering, and patterns of p53 gene mutations differ among these two low-risk populations.

Comparison of acquired mutations in the p53 tumor suppressor gene can illuminate factors contributing to carcinogenesis among cancer cohorts. Japan has an ethnically homogeneous population with a low incidence of breast cancer. Previously we reported an unusual frequency, allelic status, and clustering of mutations in breast cancers from the northern part of the main Japanese island. To extend these findings, exons 2-11 and adjacent intronic sequences were analysed in tumors of women from northern (Hokkaido) and southern (Tokushima) Japan. The frequency of breast cancers with p53 gene mutations in the Hokkaido group is the highest reported (81%) while that in Tokushima (28%) is similar to most other populations. Thirteen of the 19 mutations (68.4%) in the Hokkaido cohort were heterozygous, an unusually high frequency for p53 mutations in any tumor type. There were three missense mutations at codon 175, a known hotspot for alterations in the p53 gene, and three missense mutations at codon 179, a rare site for p53 changes. In addition, the patterns of p53 gene mutation differed between the two Japanese cohorts (P=0.04). The multiple differences in acquired p53 mutations suggest unsuspected biological differences among breast cancers in northern and southern Japan. In addition, the high frequency of p53 mutations in breast cancers from Hokkaido predicted a poorer prognosis for this population which was confirmed on examination of mortality data.

Adult↗
PubMed1996

Ductal Carcinoma In Situ of the Breast: Is Breast Conserving Treatment Feasible?

Between 1968 and 1993, 43 cases of ductal carcinoma in situ of the breast (DCIS) were treated. We examined the extent of the cancer using multiple sections of surgical specimens and considered whether or not breast conserving treatment (BCT) is feasible for treatment of DCIS. In nine out of 40 patients (23%), extent of the cancer was classified as grade III, defined as extension over a 2.5-cm margin around the tumor. Among those nine cases, 67% (6/9) had extensive microcalcification on mammography. With respect to the correlation between the tumor size and the extent of the cancer, 29%(5/17) of the cases with a small size tumor, ie, 1.0 cm or less, showed grade III or greater. All tumors with a size of 1.1-2.0 cm showed grade II or lower, and 50%(4/8) of cases with a tumor size of 2.1 cm or more showed grade III or greater. Concerning the relationship between the histological subtype and the extent of the cancer, 22%(2/9) of comedo carcinomas and 23%(7/30) of noncomedo carcinomas showed grade III or greater. The histological extent thus showed no difference between comedo carcinoma and noncomedo carcinoma. It follows that, when BCT performed on DCIS consists of lumpectomy alone, BCT is feasible when the tumor size is 1.1-2.0 cm. without extensive microcalcification on mammography. However, BCT for comedo carcinoma should be approached with caution because of its malignant behavior, although there was no difference in histological extent between comedo and noncomedo carcinoma.

Journal Article↗
PubMed1996

Pioglitazone improves insulin signaling defects in skeletal muscle from Wistar fatty (fa/fa) rats.

The effects of pioglitazone, a novel antidiabetic insulin-sensitizing agent, on insulin signaling in skeletal muscles from genetically obese Wistar fatty rats and their lean littermates were studied. Increased tyrosine phosphorylation levels of insulin receptors (IRs) and insulin receptor substrate 1 (IRS-1) in response to insulin were not observed in fatty rats. Insulin-stimulated phosphatidylinositol (PI) 3-kinase activity was reduced in fatty rats. Administration of pioglitazone (3 mg/kg/day) to fatty rats for 10 or 18 days reversed the decline in the insulin-stimulated tyrosine phosphorylated IR and IRS-1 levels and the reduced insulin-stimulated PI 3-kinase activities. In contrast, insulin-stimulated tyrosine phosphorylation of IR and IRS-1 and PI 3-kinase activity in lean rats was not changed by pioglitazone. IR expression in fatty rats was down-regulated, which was not affected by pioglitazone. There was no difference between the PI 3-kinase expression levels in fatty and lean rats and pioglitazone did not change these expression levels. These results indicate that pioglitazone can correct the insulin signaling defects of Wistar fatty rats, thereby ameliorating insulin resistance.

Animals↗
PubMed1996

The influence of blood gas changes on hyperthermia-induced seizures in developing rats.

Fever induces seizures in infants with febrile convulsions or epilepsy. Hyperpnea induced by fever may contribute to the induction of these seizures. In order to examine this possibility, we evaluated the effect of changes in arterial blood gas tension on hyperthermia-induced seizures in developing rats. Electrical seizure discharges were induced by application of infra-red rays on the skull of rats under mechanical ventilation with different respiratory conditions. There was positive correlation between pCO(2) and the seizure threshold (ST) defined as a latency from the start of hyperthermia to the occurrence of seizures: ST (seconds, s) = 2.36 pCO(2) + 0.05 (R(2) = 0.80, P < 0.001). Seizure duration (SD) was longer at lower pCO(2) level: 18 (6-33) (median, range) s at pCO(2) ranging from 23 to 26 mmHg vs. 0 (0-7) s at pCO(2) ranging from 35 to 57 mmHg (P < 0.01). Hypoxia significantly increased ST: 84 (61-100) s at P0(2) ranging from 53 to 76 mmHg vs. 60 (51-72) s at P0(2) ranging from 87 to 131 mmHg (P < 0.01). Hyperoxia prolonged SD: 27 (10-30) s at P02 ranging from 100 to 170 mmHg vs. 9 (0-23) at P0(2) ranging from 53 to 93 mmHg (P < 0.02). Hypocarbia caused by fever-induced hyperpnea probably contributes to the generation of fever-induced seizures.

Animals↗
PubMed1996

Only the first and the last hydrophobic segments in the COOH-terminal third of Na,K-ATPase alpha subunit initiate and halt, respectively, membrane translocation of the newly synthesized polypeptide. Implications for the membrane topology.

We studied the topogenic properties of five hydrophobic segments (H5-H9) in the COOH-terminal third of Na,K-ATPase alpha subunit using in vitro insertion of fusion proteins into endoplasmic reticulum membranes. These fusion proteins consisted of several different lengths of truncated alpha subunit starting at Met729 and a reporter protein, chloramphenicol acetyltransferase, that was linked in frame after each hydrophobic segment. We found that membrane insertion of the newly synthesized COOH-terminal third was initiated by H5 and terminated by H9, indicating that here only H5 and H9 have topogenic function. The other three, H6-H8, did not have topogenic function in the native context and were translocated into the endoplasmic reticulum lumen. These results were in striking contrast to the previous models in which four or six hydrophobic segments were proposed to cross the membrane. Furthermore, the findings suggest a novel mechanism for achieving the final membrane topology of the COOH-terminal third of the alpha subunit.

Amino Acid Sequence↗
PubMed1996

Retinol binding protein and transthyretin are secreted as a complex formed in the endoplasmic reticulum in HepG2 human hepatocarcinoma cells.

Retinol binding protein (RBP), the retinol-specific carrier, circulates in blood as a 1:1 complex with the homotetrameric protein transthyretin (TTR). Both RBP and TTR are synthesized and secreted by the hepatocyte. In this work we have demonstrated, using HepG2 cells as a model system, that the association between the two proteins occurs inside the cell before secretion. The intracellular complex was detected only when metabolically labeled cells were lysed under mild detergent conditions (1.5% octylglucoside), followed by immunoprecipitation and SDS-PAGE. Alternatively, the immunoprecipitates from unlabeled cells lysed with the same buffer were analyzed by Western blotting. This finding was confirmed using the cross-linking agent dithiobis(succinimidyl) propionate before cell lysis. Moreover, we found that in cells treated with brefeldin A to block the exit of proteins from the endoplasmic reticulum (ER), the complex was present in the microsomal fraction. Thus, we can conclude that the RBP-TTR complex is formed inside the cell, more precisely within the ER. As RBP and TTR both lack an ER retention signal, we considered the possible involvement of chaperones in RBP and TTR retention in the ER and in complex formation. We found that calnexin, an ER integral membrane protein which functions as a chaperone, coprecipitates with RBP and TTR when cell lysis and immunoprecipitation are performed under mild conditions (1% Triton X-100). This result strongly suggests that calnexin may be involved in RBP and TTR retention in the ER, in TTR tetramer assembly, and possibly in complex formation.

Brefeldin A↗
PubMed1996

Gastric stump carcinoma after partial gastrectomy for benign gastric lesion: what is feasible as standard surgical treatment?

METHOD: Clinicopathological features and prognostic factors were evaluated in 26 cases of stump carcinoma, operated on in the recent 20 years, in search of the standard surgical treatment. BACKGROUND: Stump carcinoma usually emerges more than 20 years after the initial gastrectomy and is often not diagnosed in the early clinical stage, resulting in a significantly low incidence of curative resection compared with primary gastric carcinoma. RESULTS: No improvement in the survival curves for stump carcinoma was observed between the past two decades. Nodal metastases were frequently found within the first tier nodes, and no 5-year survivor was found among the patients with nodal metastasis beyond pN1. CONCLUSIONS: Subtotal gastrectomy might suffice for the treatment of stomal cancer, and most patients might not benefit from extensive lymphadenectomy.

Carcinoma↗
PubMed1996

Difference in onset of warm ischemia and reperfusion injury between parenchymal and endothelial cells of the liver. Evaluation by purine nucleoside phosphorylase and hyaluronic acid.

The onset of warm ischemia and reperfusion injury in the liver was investigated in a canine model through changes in parenchymal markers [isozyme class V of lactate dehydrogenase (LDH) and alanine aminotransferase (ALT)], endothelial markers [purine nucleoside phosphorylase (PNP) and hyaluronic acid clearance], and the liver metabolism (ketone body ratio) in warm ischemia induced by inflow occlusion using Pringle's maneuver and subsequent reperfusion. In this in vivo model, a PNP assay system and a model were designed so as to exclude the influence of wide localization of PNP possibly originating in erythrocytes or the intestine, and to discriminate between PNP of endothelial cells and that of parenchymal cells in the liver. After 45 min of warm ischemia, reperfusion resulted in damage only to endothelial cells, as seen by significant increase in PNP alone (3.6 +/- 0.1 U/liter at the end of warm ischemia to 6.8 +/- 0.5 U/liter at 5 min after reperfusion, P < 0.01) and significant decrease in hyaluronic acid clearance compared to the 30-min warm ischemia group in which no increase in either marker for parenchymal and endothelial cells was noted. By contrast, after 60 min of warm ischemia, reperfusion resulted in damage to parenchymal cells along with damage to endothelial cells, as seen by significant increases in LDH(V) and ALT (93 +/- 4 U/liter and 32 +/- 2 IU/liter at the end of warm ischemia to 239 +/- 17 U/liter and 165 +/- 27 IU/liter at 5 min after reperfusion, respectively), as well as a marked increase in PNP and deterioration of hyaluronic acid clearance compared to the 45-min warm ischemia group. Reperfusion after 120 min of warm ischemia did not show recovery of metabolic function of the liver as evaluated by hepatic mitochondrial redox state. It is suggested that a time lag occurs in the onset of injury between parenchymal cells and endothelial cells and that endothelial cells are temporally earlier in failing than parenchymal cells when the liver is exposed to short-term warm ischemia and subsequent reperfusion.

Alanine Transaminase↗
PubMed1996

Long-duration xenogeneic extracorporeal pig liver perfusion with human blood.

Hepatic xenografts can tolerate hyperacute rejection owing to their lower susceptibility to humorally mediated injury. We investigated the possibility of long-duration xenoperfusion without immunologically controlling natural antibodies or complements. Pig livers were perfused for 9 h with human blood (Group 1) or pig blood (Group 2). Physiological conditioning and administration of prostaglandin E1 and insulin was characteristic of our system. The portal vein and hepatic artery pressure and bile production did not significantly differ between the two groups. Despite a gradual decrease throughout the perfusion, overall oxygen consumption was significantly higher in Group 1. Liver enzymes were released at higher levels in Group 1. Histological examination revealed intact hepatic architecture in Group 2, while in Group 1 interlobular morphology was severely damaged by endothelial disruption, although hepatic sinusoidal architecture was preserved. It is concluded that, despite biochemically and histologically confirmed tissue injury, graft viability was well-maintained in xenoperfusion even without immunological manipulations.

Alprostadil↗
PubMed1996

Guidelines for donor selection and an overview of the donor operation in living related liver transplantation.

Guidelines for donor selection and an overview of the donor operation are reported on the basis of our experience with 120 cases of living related liver transplantation (LRLT) in pediatric patients. Once the parents had clearly expressed their desire to serve as donors, tests were performed to functionally and anatomically screen the donor livers to determine whether or not the parents' general physical condition allowed them to serve as donors. We then evaluated which of the two parental candidates was more suitable as a donor. The wishes of the family as to which parent should serve as donor was considered secondary and taken into account only in a few cases in which certain functional and/or anatomical abnormalities were uncovered that made the prime candidate less suitable. For the 120 LRLTs, 135 candidates were evaluated as potential donors, 15 (11.1%) of whom were rejected for various reasons. The mean volume of blood loss during the donor operation decreased significantly from 489 g in the first 60 LRLTs to 390 g in the latter 60 LRLTs; this was accompanied by a significant decrease in the mean volume of autologous blood transfused from 449 g to 390 g. Mean cold ischemia time of the graft increased significantly from 71.4 to 128.0 min, while mean operation time conversely decreased from 6.7 to 6.2 h. Bile leakage from the cut surface of the remnant liver, which was the only post-operative surgical complication encountered, was noted in five cases. We conclude that donor candidates should be strictly selected according to basic guidelines, taking into account both the results of preoperative screening and the wishes of the family. With this accumuled experience, we have been able to simplify our LRLT operative procedure, resulting in decreases in blood loss volume, blood transfused, and operation time.

ABO Blood-Group System↗
PubMed1996

Characteristics of intracranial aneurysms associated with moyamoya disease. A review of 111 cases.

A retrospective analysis of 111 patients with aneurysms associated with Moyamoya disease is presented. The subjects comprised of our 12 cases and 99 other well-documented cases. These 111 cases had 131 aneurysms. There were 48 males and 63 females. The average age was 40.3 years. The clinical manifestations were intracranial haemorrhage in 99 cases (89%), and ischaemic events in 9 cases (8%), but no mention was made of these in the last three cases (2%). The Hunt and Kosnik grades were grade 1 in 8%, grade 2 in 23%, grade 3 in 31%, grade 4 in 35%, and grade 5 in 3%. Of the 131 aneurysms, 73 (56%) were found distributed around the circle of Willis, 24 (18%) in the basal ganglia, 29 (22%) on collateral vessels, and 5 (4%) on other vessels. Forty-six percent of the cases were treated surgically, 51% conservatively, and 3% by endovascular procedures. The surgical procedures for the aneurysms were; neck clipping in 49%, aneurysmectomy in 18%, wrapping of the aneurysm in 11%, coating or cautery of the aneurysm in 7%, and revascularization only in 11%. The outcomes were Glasgow Outcome Scale 1 in 30%, 2 in 22%, 3 in 11%, 4 in 1%, and 5 in 25%. The main reasons for the unfavourable outcome were initial poor clinical grade and rebleeding. Follow-up angiography of 25 aneurysms demonstrated that all aneurysms in the basal ganglia or on the collateral vessels disappeared. We recommend surgical intervention for aneurysms associated with Moyamoya disease to prevent rupture or rebleeding, especially for aneurysms around the circle of Willis. However, direct surgery is not recommended for aneurysms found in the basal ganglia or on the collateral vessels.

Adolescent↗