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T Shimomura

Publications and source records attributed to T Shimomura.

At least 19 recordsLinked to original sources
PubMed1997

Hepatocyte growth factor activator inhibitor, a novel Kunitz-type serine protease inhibitor.

Hepatocyte growth factor (HGF) activator is a serine protease that is produced and secreted by the liver and circulates in the blood as an inactive zymogen. In response to tissue injury, the HGF activator zymogen is converted to the active form by limited proteolysis. The activated HGF activator converts an inactive single chain precursor of HGF to a biologically active heterodimer in injured tissue. The activated HGF may be involved in the regeneration of the injured tissue. In this study, we purified an inhibitor of HGF activator from the conditioned medium of a human MKN45 stomach carcinoma cell line and molecularly cloned its cDNA. The sequence of the cDNA revealed that the inhibitor has two well defined Kunitz domains, suggesting that the inhibitor is a member of the Kunitz family of serine protease inhibitors. The sequence also showed that the primary translation product of the inhibitor has a hydrophobic sequence at the COOH-terminal region. Inhibitory activity toward HGF activator was detected in the membrane fraction as well as in the conditioned medium of MKN45 cells. These results suggest that the inhibitor may be produced as a membrane-associated form and secreted by the producing cells as a proteolytically truncated form.

Amino Acid Sequence↗
PubMed1997

Premorbid brain size as a determinant of reserve capacity against intellectual decline in Alzheimer's disease.

OBJECTIVE: Both the magnitude of brain atrophy and premorbid brain size determine the volume of the brain affected by Alzheimer's disease. To examine the possibility that premorbid brain volume is a determinant of cognitive reserve in patients with Alzheimer's disease, the relation between diffuse brain atrophy and cognitive decline and the impact of premorbid brain size on cognitive decline were studied in patients with Alzheimer's disease. METHOD: By measuring whole brain volume and intracranial volume in 60 patients with probable Alzheimer's disease, mild to moderate in severity, with the use of high-resolution magnetic resonance imaging and image processing, the authors studied the impact of premorbid brain volume and magnitude of diffuse brain atrophy on cognitive functions. On the basis of the normative brain-calvarium relationship derived from data an 28 healthy adults and the total intracranial volume measure of each patient, the magnitude of brain atrophy and premorbid brain volume were estimated. RESULTS: After control for the effects of age, sex, and education as confounding factors, it was found that the Alzheimer's disease patients' intelligence was correlated both positively with premorbid brain volume and negatively with magnitude of brain atrophy, while impairments in language and memory were correlated with magnitude of brain atrophy but not with premorbid brain volume. CONCLUSIONS: These findings partially support the hypothesis that premorbid brain volume is a determinant of reserves against intellectual decline in Alzheimer's disease.

Adult↗
PubMed1997

Mobilization of the internal carotid artery for basilar artery aneurysm surgery. Technical note.

The authors describe a technique for mobilization of the internal carotid artery (ICA) for basilar artery (BA) aneurysm surgery. Using the epidural approach, the anterior clinoid process, orbital roof, and optic canal are drilled away. The ICA is made mobile to the C3 segment by cutting the dural ring and dissecting the ICA from the carotid groove. The ophthalmic artery is then dissected from the optic canal. This mobilization of the ICA secures wide operative fields on both its medial and lateral sides and permits complete clipping of BA aneurysms.

Basilar Artery↗
PubMed1996

Rfc5, a small subunit of replication factor C complex, couples DNA replication and mitosis in budding yeast.

The inhibition of DNA synthesis prevents mitotic entry through the action of the S phase checkpoint. In the yeast Saccharomyces cerevisiae, an essential protein kinase, Spk1/Mec2/Rad53/Sad1, controls the coupling of S phase to mitosis. In an attempt to identify genes that genetically interact with Spk1, we have isolated a temperature-sensitive mutation, rfc5-1, that can be suppressed by overexpression of SPK1. The RFC5 gene encodes a small subunit of replication factor C complex. At the restrictive temperature, rfc5-1 mutant cells entered mitosis with unevenly separated or fragmented chromosomes, resulting in loss of viability. Thus, the rfc5 mutation defective for DNA replication is also impaired in the S phase checkpoint. Overexpression of POL30, which encodes the proliferating cell nuclear antigen, suppressed the replication defect of the rfc5 mutant but not its checkpoint defect. Taken together, these results suggested that replication factor C has a direct role in sensing the state of DNA replication and transmitting the signal to the checkpoint machinery.

Amino Acid Sequence↗
PubMed1996

Activation of hepatocyte growth factor in the injured tissues is mediated by hepatocyte growth factor activator.

Hepatocyte growth factor (HGF) is a potent mitogen, motogen, and morphogen for epithelial cells in vitro. It appears likely that HGF participates in tissue regeneration following hepatic and renal injury in vivo. The activity of HGF is localized to the injured tissues by a proteolytic activation system; HGF remains as an inactive single-chain form in the normal state and is converted to an active heterodimeric form in response to tissue injury. A protease responsible for this conversion is induced in the injured liver, but it has not yet been identified. We have previously purified and characterized HGF activator (HGFA), a serum-derived serine protease that efficiently activates single-chain HGF in vitro. In this study, we found that the HGF-converting activity in the injured liver was inhibited by an anti-HGFA antibody. We also found that the active form of HGFA was generated exclusively in the injured tissues. Thus, it appears likely that HGFA is the key enzyme that regulates the activity of HGF in the injured tissues. We also analyzed the heparin binding properties of the precursor and mature forms of HGFA. HGFA had a weak affinity for heparin near the physiological salt concentration in its precursor form but acquired a strong affinity for heparin upon activation that is linked to blood coagulation. This property may ensure the local action of this enzyme at the site of tissue injury.

Animals↗
PubMed1996

Clinical features of the haemorrhage type moyamoya disease based on 31 cases.

We evaluated and analysed our own 31 cases of the haemorrhagic type of moyamoya disease to clarify the clinical features of this disease. The cases were divided into three groups. Group A consisted of 12 cases with aneurysms. Aneurysms on the circle of Willis were treated as ordinary saccular aneurysms. Group B consisted of 14 cases with intracerebral haemorrhage (ICH) without aneurysms. These were managed almost as spontaneous ICH. Group C consisted of 5 cases with intraventricular haemorrhage (IVH) without aneurysms or ICH. Twenty-two surgical procedures for aneurysms, ICH and IVH were done in 19 cases (62%). Nineteen procedures for preventing future strokes were undertaken in 11 cases (35%). The overall initial outcome was excellent in 12 cases (39%), good in 7 cases (23%), poor in 7 cases (23%), and death in 5 cases (15%). During the follow-up period (mean: 6.5 years), rebleeding occurred in two cases (8%), and ischaemic attacks in two cases (8%). The rate of rebleeding or ischaemic attacks was 1.19% per patient-year during the follow-up period. There was no ischaemic or rebleeding episode in cases treated by STA-MCA bypass with encephalomyosynagiosis (EMS) during the follow-up period. Management of the primary haemorrhage should be according to the clinical condition, type of haemorrhage, and source of haemorrhage. When the patient needs to undergo revascularization surgery to prevent future strokes, we recommend STA-MCA bypass with EMS instead of encephaloduro-arteriosynangiosis (EDAS).

Adult↗
PubMed1996

Expression and functional characterization of the P-selectin glycoprotein ligand-1 in various cells.

We have examined the expression and function of P-selectin glycoprotein ligand-1 (PSGL-1), which is a high affinity ligand for P-selectin. Northern blot and flow cytometric analysis demonstrated that a variety of hematopoietic cells and cell lines expressed PSGL-1. However, P-selectin binding ability was dependent on the additional expression of a carbohydrate structure, sialyl Lewis x (sLex). All the peripheral lymphocytes expressed PSGL-1 and subpopulation expressed sLex. Two color analysis showed that the majority of the cells that bound P-selectin were sLex-negative I lymphocytes, and most of the sLex-positive cells were B lymphocytes that did not blind P-selectin, indicating that the carbohydrate on T lymphocytes recognized by P-selectin is not sLex, and that the sLex on B lymphocytes is not readily presented for P-selectin recognition. Transfected 293 cells detectably bound P-selectin only when the cells expressed both PSGL-1 and sLex. When cysteine 310 of PSGL-1 was mutated to alanine, P-selectin binding was markedly reduced, suggesting the importance of dimerization of PSGL-1. These findings indicate that a preferable conformation of both carbohydrate and protein structure is necessary for a functional P-selectin ligand.

B-Lymphocytes↗
PubMed1996

Oligoclonal accumulation of T cells in peripheral blood from patients with idiopathic thrombocytopenic purpura.

To determine whether clonal T cells accumulate in idiopathic thrombocytopenic purpura (ITP), we performed single-strand conformation polymorphism (SSCP) analysis to detect T-cell receptor (TCR) beta-chain usage of peripheral T cells. We detected significantly more oligoclonal T cells (15.5 +/- 8.9 bands representative for clonal T-cell expansions) in peripheral blood from ITP patients than from healthy donors (2.8 +/- 2.6 bands). Frequently used V beta genes in these accumulated T cells in ITP were V beta 3, 6, 10, 13.1 and 14. To determine whether these bands were derived from clonal T cells, presumably in a preactivated state, we established some T-cell clones (expressing CD4 and TCR V beta 6. 13.1. or 14) by nonspecific stimulation from patients peripheral mononuclear cells, and examined their clonotypes. Clonal identities for three out of seven clones tested were confirmed using SSCP analyses to compare the migration of their beta-chain complementarity determining region 3 (CDR3) cDNAs, expanded by polymerase chain reaction (PCR) with those from peripheral blood. Therefore, distinctive T-cell clones accumulated in the periphery in ITP and they may be related to the autoimmune-mediated destruction of platelets.

Adult↗
PubMed1996

Salivary substance P, 5-hydroxytryptamine, and gamma-aminobutyric acid levels in migraine and tension-type headache.

Substance P, 5-hydroxytryptamine, and gamma-aminobutyric acid levels in saliva were measured in 55 patients with migraine during headache attacks (15 men and 40 women, average age 37.6 years), 36 patients with migraine in interictal periods (8 men and 28 women, average age 43.9 years), 48 patients with tension-type headache during headache attacks (18 men and 30 women, average age 47.3 years), and 25 patients with tension-type headache in interictal periods (10 men and 15 women, average age 48.6 years). Forty-three normal healthy volunteers composed the control group (17 men and 26 women, average age 32.7 years). Substance P levels in saliva were determined using competitive enzyme-linked immunosorbent assay, and were 26.9 +/- 45.1 pmol/mL in the patients with migraine during headache attacks, 30.0 +/- 59.7 pmol/mL in the patients with migraine in interictal periods, 243.5 +/- 1137 pmol/mL in the patients with tension-type headache during headache attacks, 101.3 +/- 364 pmol/mL in the patients with tension-type headache in interictal periods, and 21.2 +/- 17.4 pmol/mL in the healthy controls. 5-hydroxytryptamine levels in saliva were determined using reversed-phase high-performance liquid chromatography with electrochemical detection, and were 895 +/- 1075 ng/mL in the patients with migraine during headache attacks, 758 +/- 1375 ng/mL in the patients with migraine in interictal periods, 1646 +/- 1945 ng/mL in the patients with tension-type headache during active headache periods, 1167 +/- 1495 ng/mL in the patients with tension-type in headache-free periods, and 450 +/- 405 ng/mL in the healthy controls. Gamma-aminobutyric acid levels in saliva were determined using high-performance liquid chromatography with precolumn ortho-phthalaldehyde fluorescence detection. Gamma-aminobutyric acid levels in saliva were 36.8 +/- 49.8 pmol/mL in the patients with migraine during headache attacks, 17.9 +/- 25.2 pmol/mL in the patients with migraine in interictal periods, 16.0 +/- 18.3 pmol/mL in the patients with tension-type headache during active headache periods, 14.1 +/- 6.8 pmol/mL in the patients with tension-type headache in headache-free periods, and 21.6 +/- 22.7 pmol/mL in the healthy controls. The salivary substance P and 5-hydroxytryptamine levels in the patients with tension-type headache during active headache periods were significantly higher than those in healthy controls. In contrast, we found no significant differences between the salivary gamma-aminobutyric acid levels in the patients with tension-type headache and healthy controls. The high levels of salivary substance P and 5-hydroxytryptamine in tension-type headache patients during headache periods might reflect release of substance P from the pain sensory system. Saliva could represent a fluid particularly suitable to the study of neuropeptide release under specific conditions such as migraine and tension-type headache.

Adult↗
PubMed1996

[Huge skull base neurofibroma: case report].

A case of a huge skull base neurofibroma completely resected by a combined subtemporal-infratemporal and basal subfrontal approach is reported. A 32-year-old female complained of left facial paresthesia and deformity since several months before. Neurological examination revealed hypesthesia in the distribution of the left trigeminal nerve second branch. CT and MRI images showed a huge tumor in the infratemporal fossa, parapharyngeal space and middle fossa extending into the cavernous sinus, compressing the left temporal lobe and distorting the left hypothalamus and the brain stem. The patient tolerated trial balloon occlusion of the left internal carotid artery for 45 minutes. Transmaxillary biopsy revealed the tumor to be a neurofibroma. Through a combined basal subfrontal and a subtemporal-infratemporal approach in two staged operations, total tumor resection was performed. This tumor originated at the second branch of the trigeminal nerve. We recommend these combined approaches and two staged operations for such a huge skull base tumor as presented in this case.

Adult↗
PubMed1996

An alternative elastase-mediated degradation of fibrinogen and fibrin observed in a patient with herpes simplex encephalitis and pneumonia.

A 74-year-old female developed pneumonia following herpes simplex encephalitis. Her white blood cell counts reached 28,400/microliters, about 90% of which consisted of granulocytes. The polymorphonuclear (PMN) elastase/alpha 1-antitrypsin complex levels increased and reached the maximum of 5,019 ng/ml, indicating the release of a large amount of elastase derived from the granulocytes. The mechanism of PMN elastase release was most likely to be granulocyte destruction associated with phagocytosis. The cleavage of fibrinogen and fibrin by PMN elastase, independent of plasmin, was indicated by the presence of the fragments in immunoprecipitated plasma from the patient corresponding to elastase-induced FDP D and DD fragments and the absence of fragments corresponding to plasmin-induced FDP D and DD fragments on SDS-PAGE. These findings suggested that the large amount of PMN elastase released from the excessive numbers of granulocytes in this patient with herpes simplex encephalitis and pneumonia, induced the cleavage of fibrinogen and fibrin without the participation of plasmin.

Aged↗
PubMed1996

A point mutation in glycoprotein IX coding sequence (Cys73 (TGT) to Tyr(TAT)) causes impaired surface expression of GPIb/IX/V complex in two families with Bernard-Soulier syndrome.

Bernard-Soulier syndrome (BSS) is a rare inherited bleeding disorder which is caused by abnormal expression or function of the glycoprotein (GP) Ib/IX/V complex, a platelet major receptor for von Willebrand factor. We studied four BSS patients in two unrelated families in which the same and novel mutation was found. Flow cytometric analysis showed that GPIX was completely absent but residual amounts of GPIb alpha and GPV were detectable in these patients. We analyzed all coding regions of GPIb alpha, GPIb beta, GPV and GPIX which were amplified from the patients' genomic DNA by the polymerase chain reaction (PCR). In all four cases, we identified a point mutation in the GPIX coding region that changes the codon for cysteine 73 (TGT) to a codon for tyrosine (TAT). Furthermore, we confirmed by a transient expression study that the mutation caused the loss of adequate surface expression of GPIX. Since cysteine might be important for the secondary structure, this mutation of GPIX gene would lead to a dramatic conformational change of GPIX protein, resulting in the reduced surface expression. We concluded that this novel point mutation of the GPIX gene was responsible for BSS in these families.

Adult↗
PubMed1996

[The efficacy of short-term hospitalizations in family care for patients with Pick's disease].

The purpose of this study is to investigate the efficacy of short-term hospitalization on family care for patients with Pick's disease (PD). Subjects were 12 patients with clinical diagnosis of PD based on clinical and neuroimaging criteria. They were selected from 483 patients with cognitive disorders who had been admitted to our hospital from January, 1994 to September, 1995. During 1.5-month hospital stay, we gave therapeutic intervention to the patients and their care-givers. Ten patients completed the planned term (1.5 months) of hospitalization. After the discharge, 9 patients continued to visit regularly the outpatient clinic. One patient discontinued to visit us and 2 patients were admitted to psychiatric hospitals because of stereotypic thefts or disinhibitional behavior. The benefits of short-term hospitalization in family care for PD patients were; i) close observation and analysis of patients' behavior under hospitalization offering strategies of behavioral therapy; ii) adequate instruction to the care-givers for their preparation for patients' malbehavior decreasing their burden; and iii) patients' familiarization to the hospital helping for patients to maintain regular visit to the hospital and to utilize other medical and social resources.

Adult↗
PubMed1995

50-kD integrin-associated protein does not detectably influence several functions of glycoprotein IIb-IIIa complex in human platelets.

A 50-kD integrin-associated protein (IAP) has been reported to be associated with beta 3 integrins and to modulate their function, especially vitronectin receptor in human erythroleukemia (HEL) cells and leukocyte response integrin in neutrophils. We studied the involvement of IAP in the function of platelet beta 3 integrin, glycoprotein (GP) IIb-IIIa complex. IAP was a widely distributed protein and was also expressed in the cells that do not have beta 3 integrin. Platelets from a patient with thrombasthenia, which lack GPIIb and IIIa, expressed IAP as well as normal platelets. Neither platelet aggregation nor intracellular Ca2+ elevation after stimulation was influenced by the anti-IAP antibody, B6H12, which was reported to be inhibitory for other beta 3 integrins. The expression level of GPIIb-IIIa complex was not influenced by coexpression of human IAP in the transfected Chinese hamster ovary (CHO) cells. IAP did not facilitate the binding of soluble fibrinogen to the CHO cells expressing GPIIb-IIIa complex. Furthermore, cell adhesion onto the immobilized fibrinogen via GPIIb-IIIa complex was not inhibited by B6H12 in HEL cells and was not altered by coexpression of human IAP in CHO cells. We concluded that expression of IAP is regulated independently with that of GPIIb-IIIa complex and that IAP does not influence the function of GPIIb-IIIa complex.

Animals↗
PubMed1995

Activation of hepatocyte growth factor by two homologous proteases, blood-coagulation factor XIIa and hepatocyte growth factor activator.

Hepatocyte growth factor (HGF) is secreted as an inactive single-chain precursor from the producing cells, and normally remains in this form associated with the extracellular matrix. In response to tissue injury, the single-chain precursor is converted to a biologically active heterodimer by a serine protease, the activity of which is induced in the injured tissue. We have previously identified HGF activator, a serum serine protease that activates single-chain HGF. The sequence of HGF activator cDNA revealed that the HGF activator is homologous to blood-coagulation factor XIIa. In this study, we found that coagulation factor XIIa has an ability to activate single-chain HGF. Factor XIIa exhibited a significant level of HGF-converting activity in the presence of dextran sulfate, although the specific activity of factor XIIa was slightly lower than that of the HGF activator. Since factor XIIa is activated during the initiation of contact activation induced by tissue injury, factor XIIa may function as an HGF-converting enzyme together with HGF activator in the injured tissue. C1-inhibitor, antithrombin III and alpha 2-antiplasmin, that regulate the blood-clotting activity of factor XIIa, were also effective against the HGF-converting activity of factor XIIa. Furthermore, factor XIIa was not active in the HGF-converting activity in serum. Thus, the HGF-converting activity of factor XIIa may be regulated by these serum inhibitors.

Factor XIIa↗
PubMed1995

Effective anticonvulsant therapy in a patient with limb shaking: a case report.

A case is described of a patient with limb shaking in whom anticonvulsant therapy was effective for inhibiting attacks. A 70 year old female developed rhythmical involuntary limb shaking of the right upper and lower limb in April 1986. She was diagnosed as having transient ischemic attacks and was followed up under treatment with an antiplatelet drug. Subsequently, anticonvulsant therapy was also initiated on an outpatient basis. In August 1991, she was admitted with shaking of the right upper and lower limbs. Low molecular dextran was ineffective for inhibiting limb shaking attacks, but intravenous injection of diazepam was effective. Phenytoin and phenobarbital was used in combination. No limb shaking attacks occurred thereafter. The involuntary movement was the same as that observed at the onset of the disease. Though no changes were observed in the pattern of the involuntary movement, anticonvulsant therapy was effective in preventing and inhibiting attacks. This finding is inconsistent with previous reports. It is possible that epileptic factors are involved in the development of this condition.

Aged↗
PubMed1995

Cu, Zn superoxide dismutase in patients with dementia of the Alzheimer type.

Cu, Zn superoxide dismutase (SOD) levels in the serum, cerebrospinal fluid (CSF) and skin fibroblasts of patients with dementia of the Alzheimer type (DAT) were estimated using enzyme immunoassay. The SOD mRNA level in the skin fibroblasts was also determined by the Northern blot analysis. As compared with the age-matched control groups of neurological patients without dementia, the AD group consisting of patients with DAT at ages under 65 years of age as well as the SDAT group of patients with DAT at ages over 65 years of age showed no significant changes in serum or CSF SOD levels. However, the skin fibroblast SOD- and SOD mRNA levels, which were correlate each other, were significantly higher in the AD group (p < 0.05), while lower in the SDAT group (p < 0.05). These results suggest that the determination of the SOD level of skin fibroblast may be useful for diagnosis of DAT and that the abnormality of SOD may play an important role in developing DAT.

Alzheimer Disease↗