Biomedical subjects

S Nishimura

Publications and source records attributed to S Nishimura.

At least 73 records · Page 4Linked to original sources

PubMed2001

Human N-acetylglucosaminyltransferase I. Expression in Escherichia coli as a soluble enzyme, and application as an immobilized enzyme for the chemoenzymatic synthesis of N-linked oligosaccharides.

N-Acetylglucosaminyltransferase I (GnT-I), which catalyzes the transfer of an N-acetylglucosamine residue from UDP-N-acetylglucosamine to the alpha1,3-linked mannose on Man5GlcNAc2 (M5), is a critical enzyme for the synthesis of high-mannose-type to complex-type glycan structures in N-linked glycan processing. We developed a large-scale preparation system for recombinant human GnT-I (hGnT-I) using the maltose binding protein (MBP) fusion system to facilitate the chemoenzymatic route for complex-type N-linked glycan synthesis. MBP-fused GnT-I was purified by affinity chromatography on an amylose resin column. The relative activity of MBP-fused GnT-I toward high-mannose-type N-linked oligosaccharides was 100% for Man5GlcNAc2, 52% for Man3GlcNAc2, 17% for Man6GlcNAc2. MBP-fused GnT-I exhibited optimal activity at pH 6.5-9.5 and was more active between pH 6.5-9.0. The optimum temperature for MBP-fused GnT-I activity was 40 degrees C, but the enzyme was active between 0-70 degrees C. Mn2+ and Co2+ were critical for the enzyme activity, while Zn2+ and Ca2+ inhibited the activity. Kinetic analysis of the purified enzyme showed an apparent K(m) value of 0.483 mM and a V(max) of 101 nmol/mg/min for M5. Immobilization of MBP-fused GnT-I on the amylose resin led to an 80% yield of the high mannose-type-of oligosaccharide.

Journal Article↗

PubMed2001

Anorexia nervosa with ischemic necrosis of the segmental ileum and cecum.

A 41-year-old woman with long-standing anorexia nervosa showed paralytic ileus and serum creatine kinase elevation. Surgical treatment showed necrosis of the segmental ileum and cecum with perforation. She died of septic shock 3 days after the operation. Postmortem examination revealed no occlusion of the superior mesenteric artery or its main branches, and no arteriosclerotic changes. Histological examinations confirmed non-occlusive mesenteric infarction. This case suggested that necrosis of bowels might have been caused by poor blood supply due to severe malnutrition and dehydration for many years, which could be one of the fatal complications of anorexia nervosa.

Adult↗

PubMed2001

Rapidly progressive tabes dorsalis associated with selective IgA deficiency.

Tabes dorsalis is uncommon and progresses slowly from infection to clinical manifestation. We report a rare case of rapidly progressive tabes dorsalis associated with selective IgA deficiency (sIgAD). A 28-year-old man was hospitalized with lightning back pain, nausea, and bladder bowel dysfunction. Serum and cerebrospinal fluid (CSF) revealed high titers of Treponema pallidum antibody, and the serum IgA level was less than 5 mg/dl. Thl-dominant cytokine expression was observed, as is usually seen in neurosyphilis. He was treated with Ceftriaxone and CSF pleocytosis disappeared. We postulate sIgAD influenced the atypical rapid clinical course of tabes dorsalis in this patient.

Adult↗

PubMed2001

In vivo histological changes occurring in hydroxyapatite cranial reconstruction--case report.

Histological changes were observed in a hydroxyapatite plate and hydroxyapatite granules used to repair a craniotomy defect and removed after 2 years and 9 months of use. The hydroxyapatite plates and granules had completely fused to the cranium, with new bone formation on the dural side extending in a three-dimensional matrix along the pores with the Haversian system in the center. New bone formation was less extensive under the artificial dura than under normal dura. This finding suggests that the dura has the ability to promote bone formation. A new vessel was found along the interconnecting pores. The interconnecting pores allow osteoconduction in the hydroxyapatite plate, so new bone formation can progress. Hydroxyapatite has osteoconduction properties and is biocompatible, so gains strength in vivo through new bone formation, and is the ideal material for artificial bones. Factors important to achieving good bone formation after cranial reconstruction surgery include presence of the dura, and pore size approximate to the Haversian system (100-500 microns) and interconnecting pores in the hydroxyapatite plate.

Adult↗

PubMed2001

Prognostic predictive value of 18F-fluorodeoxyglucose positron emission tomography for patients with pancreatic cancer.

18Fluorine-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) is a unique imaging diagnostic tool to evaluate glucose metabolism and hexokinase activity which may reflect the aggressiveness of a tumor. Thirty-seven patients with primary pancreatic cancer were evaluated with 18F-FDG-PET. Thirteen patients underwent resection for the pancreatic cancer and 24 patients had unresectable tumors. The standardized uptake values (SUV) of 18F-FDG in the primary tumors were calculated. No correlations were found between the SUV in the tumors and the metastatic status to the peritoneal/liver, TNM factors/stage, or resectability. The patients were divided into 2 groups with high and low SUV, with the cut-off value being 3.0 (median SUV value of 37 cases). No differences in the probability of survival were observed between the 2 groups in the patients with resectable tumors. However, in the patients with unresectable tumors, those in the high SUV group had a significantly shorter prognosis than those in the low SUV group. Moreover, a multivariate analysis of survival indicated that SUV is an independent prognostic factor for patients with unresectable pancreatic cancer.

Adenocarcinoma↗

PubMed2001

Metachromasia of the endocervical epithelium for delineating the internal os.

OBJECTIVE: To study the metachromatic stainability of the endocervical epithelium. STUDY DESIGN: Surgical specimens that included endocervical epithelium were deparaffinized and stained with toluidine blue at various pH levels and after enzyme digestion. Glycosaminoglycans were separated from endocervical tissue and analyzed by electrophoresis. RESULTS: The endocervical epithelium stained metachromatically purple with toluidine blue in pH 4.1 buffer, but the staining disappeared after chondroitinase digestion. The electrophoretic mobility of the glycosaminoglycan fraction separated from the endocervical epithelium was compatible with nonsulfated chondroitin. CONCLUSION: Endocervical epithelium was identifiable from metachromatic staining below the internal os, and the electrophoretic results of the tissue extract suggested that nonsulfated chondroitin is the main component of glycosaminoglycans in endocervical epithelium.

Cervix Uteri↗

PubMed2001

[Cavernous sinus dural arteriovenous shunt presenting with subarachnoid hemorrhage and acute subdural hematoma: a case report].

Cavernous sinus dural arteriovenous shunt (CdAVS) usually presents with exophthalmos, conjunctival chemosis, ophthalmoplegia, headache, bruit, or pulsatile tinnitus. Intracranial hemorrhage associated with CdAVS is rare. We describe a patient with CdAVS presenting with subarachnoid hemorrhage and acute subdural hematoma. A 65-year-old woman presented headache and temporary loss of consciousness and was transferred to our hospital. On admission, the patient was alert and complained of a left-sided temporal headache. There were no ocular symptoms. A CT scan revealed subarachnoid hemorrhage and left acute subdural hematoma. When we prepared for cerebral angiography, the patient presented loss of consciousness following sudden onset of severe headache. Urgent angiography revealed left CdAVS, which was fed by both the internal carotid artery and the external carotid artery and drained only into ipsilateral (left) vein of the sylvian fissure. Aneurysmal dilatation of the draining veins and leptomeningeal drainage were present. No cerebral aneurysms were detected. After the angiography, a CT scan showed enlarged subdural hematoma, so left fronto-temporo-parietal craniotomy was immediately performed. On opening the dura mater, arterial bleeding from Sylvian fissure appeared and was uncontrollable. Unfortunately, the patient died 3 days after the operation. We concluded that subarachnoid hemorrhage and subdural hematoma were due to the rupture of engorged cortical veins. Our case report suggests that CdAVS with angiographic findings such as aneurysmal dilatation of the draining veins and leptomeningeal drainage should be treated urgently because of the high risk of the life-threatening complications resulting from a surgically uncontrollable hemorrhage.

Aged↗

PubMed2001

Rainwater drainage management for urban development based on public-private partnership.

The Urban Development Corporation (UDC) is one of the biggest implementation bodies for urban development in Japan. UDC has developed rainwater infiltration technology since 1975. This technology has effectively reduced runoff to a river and sewer system in the new town project areas. Recently, UDC has developed a new system which is defined as a "Rainwater Recycle Sewer System", which is supported by "Rainwater Storage and Infiltration Technology (RSIT)" applicable to new town creation and urban renewal. The new system consists of two elements: RSIT components based on Public-Private Partnership (PPP) and a stormwater drainage system. Herein, the private sector is responsible for the main part of RSIT, and the public sector is responsible for the stormwater drainage from the development area. As a result, the capacity of public facilities, such as rainwater sewers and stormwater reservoirs, can be reduced effectively. In parallel, the initial/running cost of public facilities is expected to be reduced. In conclusion, the authors would stress the importance of a co-maintenance system also based on PPP, which will be required especially in order to properly operate the whole system for the long term.

Cities↗

PubMed2001

[A case of anaplastic astrocytoma arising 8 years after initial treatment by partial resection and irradiation for central neurocytoma].

A 31-year-old female developed the anaplastic astrocytoma in the right basal ganglia and temporal lobe 8 years after partial resection and irradiation of the central neurocytoma. Probably the malignant astrocytoma was an irradiation-induced tumor. Postoperative radiation therapy for the central neurocytoma appears to have a good effect on tumor local control. But it should be carefully decided whether to use radiation therapy for residual tumor because of the risk of delayed complications of irradiation, such as the present case.

Adult↗

PubMed2001

FK506 attenuates early ischemic neuronal death in a monkey model of stroke.

UNLABELLED: FK506 is an immunosuppressive agent that has been reported to have neuroprotective effects in several kinds of rodent models of stroke. The purpose of this study was to evaluate the neuroprotective effects of FK506 in a monkey model of stroke. METHODS: Cynomolgus monkeys underwent 3 h of occlusion followed by 5 h of reperfusion of the right middle cerebral artery (MCA) through a transorbital approach. A single bolus dose of FK506 (0.1 mg/kg) was injected intravenously 5 or 175 min after MCA occlusion. Eight hours after ischemia, a neuropathologic study was performed and the volume of ischemic damage was determined. To measure local cerebral blood flow (CBF), the cerebral metabolic rate of oxygen (CMRO(2)), and the oxygen extraction fraction during the experiments, PET scans were obtained using a steady-state (15)O continuous-inhalation method. Four consecutive PET scans (before and 2 h after ischemia and immediately and 3 h after reperfusion) were obtained on each monkey. RESULTS: Treatment with FK506 (0.1 mg/kg) 5 or 175 min after ischemia significantly reduced cortical damage 8 h after ischemia by 82% (P < 0.05) and 73% (P < 0.05), respectively. In PET studies, FK506 did not affect CBF or physiologic parameters in any treatments. In the FK506-treated group, a volume of >40% CMRO(2) reduction 3 h after reperfusion decreased significantly (P < 0.05). CONCLUSION: This study showed that FK506 showed a powerful neuroprotective effect in a nonhuman primate model of stroke. The therapeutic time window of FK506 was at least 3 h after onset. PET studies detected neuroprotective effects only in areas with >40% CMRO(2) reduction 3 h after reperfusion.

Animals↗

PubMed2001

[A case of rheumatoid arthritis associated with minimal change nephrotic syndrome].

A 55-year-old Japanese woman has been treated with various kinds of anti-rheumatic drugs under a diagnosis of rheumatoid arthritis(RA) for 18 years of disease duration. She persistently had right elbow joint pain and swelling and X-ray showed bone erosion on humerus. Thus, the synovectomy was performed with typical histopathology of RA on April 1999. On the end of February 2000, she had suddenly fatigue and anasarca with profound proteinuria of nephrotic syndrome. The renal biopsy showed minimal change glomerulopathy and no cellular infiltration in interstitial tissue by light microscopy and partial fusion of foot process by electron microscopy. Renal function was sustained normally. All of anti-rheumatic drugs including D-penicillamine(D-Pc) except NSAID were stopped and she was treated with bed rest, diet therapy, diuretics and albumin infusion without steroid therapy. Edema and proteinuria gradually disappeared. Membranous and amyloid nephropathy in RA patients associated with nephrotic syndrome are found in high incidence in literature. In low incidence, MCNS is associated with NSAID or D-Pc induced nephropathy in RA. In our case, nephrotic syndrome disappeared in 6 weeks without discontinuation of NSAID and application of steroid therapy. Thus, MCNS might be co-incidentally associated with RA.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2001

Validating a measure of religiousness/spirituality for Native Hawaiians.

Religiousness and spirituality are integral to the human experience. There is emerging literature that shows that religiousness and spirituality are associated with various mental and physical health outcomes. Yet, the development of measures to accurately assess these phenomena in health settings is still in its early stages. The difficulties in developing standardized definitions and measures relate to varying interpretations of religiousness and spirituality, a reluctance to utilize a scientific approach to understand an existential and personal experience, and multicultural distinctions. The potential for designing health interventions in which religiousness and spirituality are integrated rests upon the development of measures that are psychometrically sound. This paper reports on preliminary research that empirically assesses one measure of religiousness and spirituality for Native Hawaiians--a group besieged with an array of health problems. The measure is the Brief Multidimensional Measure of Religiousness/Spirituality (BMMRS) developed by the National Institute on Aging and the Fetzer Institute. This instrument has shown to have appropriate reliability and validity scores. A modified BMMRS was administered to 15 Native Hawaiians who underwent a cultural intervention of exercise, diet, and education in a program called Uli'eo Koa (warrior fitness). The BMMRS was slightly modified based on the literature and earlier research to be more specific to Native Hawaiians. Overall, measures of internal consistency supported the reliability of the BMMRS. The strongest subscales included the domains of "daily spiritual experiences," "religious and spiritual coping," and "religious support." Low internal consistency estimates for the items, "watches/listens to religious programs," "family makes demands," and "significant loss in faith," suggest that these items do not measure the same concept for participants. Although the intercorrelations among the subscales were generally low and with wide variability, 10 of the 17 subscales/single items were moderately to highly correlated with one another, indicating concurrent validity. These subscales, some of which assessed, "daily spiritual experiences," "religious and spiritual coping," and "organizational religiousness," suggest that core ideas on spirituality and religiousness for these participants, broadly reflect both "personal" and "organizational" viewpoints. Caution should be used in interpreting the results of the study because of limitations in the study's design. However, despite these limitations in design, this study provides empirical support for future research on religiousness and spirituality for Native Hawaiians.

Adult↗

PubMed2000

A mutant Escherichia coli tyrosyl-tRNA synthetase utilizes the unnatural amino acid azatyrosine more efficiently than tyrosine.

Alloproteins, proteins that contain unnatural amino acids, have immense potential in biotechnology and medicine. Although various approaches for alloprotein production exist, there is no satisfactory method to produce large quantities of alloproteins containing unnatural amino acids in specific positions. The tyrosine analogue azatyrosine, l-beta-(5-hydroxy-2-pyridyl)-alanine, can convert the ras-transformed phenotype to normal phenotype, presumably by its incorporation into cellular proteins. This provided the stimulus for isolation of a mutant tyrosyl-tRNA synthetase (TyrRS) capable of charging azatyrosine to tRNA. A plasmid library of randomly mutated Escherichia coli tyrS (encoding TyrRS) was made by polymerase chain reaction techniques. The desired TyrRS mutants were selected by screening for in vivo azatyrosine incorporation of E. coli cells transformed with the mutant tyrS plasmids. One of the clones thus isolated, R-6-A-7, showed a 17-fold higher in vivo activity for azatyrosine incorporation than wild-type TyrRS. The mutant tyrS gene contained a single point mutation resulting in replacement of phenylalanine by serine at position 130 in the protein. Structural modeling revealed that position 130 is located close to Asp(182), which directly interacts with tyrosyladenylate. Kinetic analysis of aminoacyl-tRNA formation by the wild-type and mutated F130S TyrRS enzymes showed that the specificity for azatyrosine, measured by the ratios of k(cat)/K(m) for tyrosine and the analogue, increased from 17 to 36 as a result of the F130S mutation. Thus, the high discrimination against azatyrosine is significantly reduced in the mutant enzyme. These results suggest that utilization of F130S TyrRS for in vivo protein biosynthesis may lead to efficient production of azatyrosine-containing alloproteins.

Alanine↗

PubMed2000

Testis developments and puberty in the male Tokara (Japanese native) goat.

In male Tokara (Japanese native) goats, testis development and the onset of puberty were studied histologically and observing sexual behaviour. Testes weight increased from 36+/-5.4 (S.E.) g (n=5) at 3 months of age to 126+/-6.3 g (n=6) at 12 months. The degree of the testis development differed among kids at 3 months of age and only one of four had produced spermatozoa in the testis. Large number of spermatozoa were always present in seminiferous tubules and epididymal ducts from 4 months of age. The diameter of seminiferous tubules increased from 133+/-9.9 microm (n=4) at 3 months to 198+/-1.0 microm (n=3) at 6 months with little increase thereafter. Mounting and pelvic thrusts onto a teaser doe started at from 9 to 14 weeks of age. Ejaculated semen contained sperm with good motility for the first time from 17 weeks. The male Tokara goat reaches puberty at around 4 months of age but testis development continues to 12 months.

Age Factors↗

PubMed2000

Transformation of Antirrhinum majus L. by a rol-type multi-auto-transformation (MAT) vector system.

A total of 11 independent beta-glucuronidase (GUS) positive hairy roots were induced following co-cultivation of leaf explants of Antirrhinum majus L. with Agrobacterium tumefaciens strain GV2260 containing rol-type multi-auto-transformation (MAT) vector pNPI702. A total of 326 adventitious shoots were regenerated from the hairy root lines on 1/2 MS medium without plant growth regulators at 25 degrees C under a 16 h/day photoperiod condition 4 months after infection of the A. tumefaciens GV2260. The absence of the rol genes in five plants was verified by polymerase chain reaction (PCR) and Southern blot analysis. Acclimatized transformants exhibited normal phenotypes in height and in the morphology of leaves and flowers. Furthermore, the GUS gene was strongly expressed in the leaves, inflorescence of the transformed plant, and the progeny. This result demonstrates that the rol-type MAT vector can be used to study gene functions controlling the morphogenesis of Antirrhinum majus plants.

Journal Article↗

PubMed2000

tRNA recognition of tRNA-guanine transglycosylase from a hyperthermophilic archaeon, Pyrococcus horikoshii.

In the biosynthesis of archaeosine, archaeal tRNA-guanine transglycosylase (TGT) catalyzes the replacement of guanine at position 15 in the D loop of most tRNAs by a free precursor base. We examined the tRNA recognition of TGT from a hyperthermophilic archaeon, Pyrococcus horikoshii. Mutational studies using variant tRNA(Val) transcripts revealed that both guanine and its location (position 15) were strictly recognized by TGT without any other sequence-specific requirements. It appeared that neither the global L-shaped structure of a tRNA nor the local conformation of the D loop contributed to recognition by TGT. A minihelix composed of the acceptor stem and D arm of tRNA(Val), designed as a potential minimal substrate, failed to serve as a substrate for TGT. Only a minihelix with mismatched nucleotides at the junction between the two domains served as a good substrate, suggesting that mismatched nucleotides in the helix provide the specific information that allows TGT to recognize the guanine in the D loop. Our findings indicate that the tRNA recognition requirements of P. horikoshii TGT are sufficiently limited and specific to allow the enzyme to recognize efficiently any tRNA species whose structure is not fully stabilized in an extremely high temperature environment.

Anticodon↗

PubMed2000

Observation of direct photons in central 158A GeV (208)P(208)b+Pb collisions

A measurement of direct photon production in 208Pb+208Pb collisions at 158A GeV has been carried out in the CERN WA98 experiment. The invariant yield of direct photons in central collisions is extracted as a function of transverse momentum in the interval 0.5 1.5 GeV/c. The result constitutes the first observation of direct photons in ultrarelativistic heavy-ion collisions. It could be significant for diagnosis of quark-gluon-plasma formation.

Journal Article↗

PubMed2000

The quantitative analysis of three action modes of volatile anesthetics on purple membrane.

We quantitatively assessed the spectroscopic changes of purple membrane in relation to the concentrations of a volatile anesthetic. As reported previously, volatile anesthetics show three modes of action on purple membrane. By using an anesthetic for which the concentration in solution could be determined spectroscopically and by applying modified analytical methods regarding the M-intermediate lifetime, we were able to clarify the quantitative relation between anesthetic concentration and each mode of action, a relation which in the past has only been described qualitatively. We also determined through the measurement of transient pH changes with pyranine that the proton pump efficiency per photochemical cycle in an action mode induced with low concentrations of anesthetic does not change from that of the native state. Moreover, we dynamically obtained the individual M-bacteriorhodopsin difference spectrum of each state at room temperature using our flash photolysis system equipped with a wavelength-tunable dye laser. These results demonstrated again that we should clearly distinguish different action modes of anesthetics according to their concentrations.

Anesthetics↗