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Biomedical subjects

Y Fujimura

Publications and source records attributed to Y Fujimura.

At least 217 records · Page 12Linked to original sources
PubMed1994

Structural elements influencing von Willebrand factor (vWF) binding affinity for platelet glycoprotein Ib within a dispase-digested vWF fragment.

We investigated the structural elements in human von Willebrand factor (vWF) that influence binding affinity for platelet glycoprotein (GP) Ib using a dispase-digested vWF fragment as a prototype (residues Leu480/Val481-Gly718 of the vWF subunit; Andrews et al, Biochemistry 28:8326, 1989). The major structural features of this fragment are a large A1-loop formed by an intrachain disulfide bond between Cys509 and Cys695 and six O-linked sugar chains. The fragment was chemically modified by (1) reduction and S-carboxyamido-methylation (R/A), (2) desialylation (DS), or (3) a combination of both (R/A-DS). The GPIb binding affinity of these fragments was basically evaluated by competitive binding assay with anti-GPIb monoclonal antibody (LJ-Ib1), a receptor blocker for vWF (Sugimoto et al, Biochemistry 30:5202, 1991). Both the prototype and the R/A fragments were also assessed for their function in shear-induced platelet aggregation. Results unambiguously demonstrated that the presence of a disulfide bridge (Cys509-Cys695) within this domain downregulates the affinity of vWF to GPIb. In addition, it was also demonstrated that the terminal sialic acids attached to six o-linked sugar chains within this domain contribute to optimal functional modulation by the antibiotic ristocetin, but not by snake venom botrocetin.

Animals↗
PubMed1994

A 28 kDa-protein with disintegrin-like structure (jararhagin-C) purified from Bothrops jararaca venom inhibits collagen- and ADP-induced platelet aggregation.

A 28 kDa-protein with inhibitory activity on collagen- and ADP-induced platelet aggregation was purified from the venom of the snake Bothrops jararaca. Its complete amino acid sequence corresponded to the carboxyl-terminal region consisting of disintegrin-like and cysteine-rich domains of jararhagin, a high molecular weight hemorrhagic metalloprotease. Sequence homology of the protein to other disintegrins and disintegrin-like proteins from various snake venoms is also presented.

Adenosine Diphosphate↗
PubMed1994

One of two Ets-binding sites in the cytokeratin EndoA enhancer is essential for enhancer activity and binds to Ets-2 related proteins.

Expression of the mouse cytokeratin EndoA gene is restricted in endodermal and epithelial cells, and is regulated by an enhancer that is located 1 kilobase (kb) 3' downstream from the gene. The enhancer consists of six direct repeats, of which each contains two predicted Ets binding sites (EBS1 and EBS2) containing GGAA as a core. Mutation analysis showed that EBS1 is essential for the enhancer activity and additional effects of EBS2, suggesting that some Ets-related proteins bind and activate the enhancer through EBS1. We also showed that Ets-2 mRNA is expressed in PYS-2 cells and that Ets-2 protein produced by E. coli interacts with EBS1 but not with EBS2. Using co-transfection assays, we showed that Ets-2 can trans-activate the enhancer in PYS-2 cells. Mutations that impair Ets-2 binding abolished the activity of the EndoA enhancer. The results obtained from the binding competition assay using an Ets-2 specific antibody, however, suggest that EBS1 binds to an Ets protein which is distinct from Ets-2. These data show that Ets-2 related protein binds and activates the EndoA enhancer in a sequence-specific fashion.

Animals↗
PubMed1994

Purification and characterization of bothrombin, a fibrinogen-clotting serine protease from the venom of Bothrops jararaca.

A fibrinogen-clotting enzyme (bothrombin) was purified from the venom of Bothrops jararaca. Bothrombin showed M(r) values of 33,000 under nonreducing and 35,000 under reducing conditions on SDS polyacrylamide gel electrophoresis and specific fibrinogen-clotting activity equivalent to 814-904 NIH alpha-thrombin units/mg. Diisopropyl fluorophosphate totally abolished its activity, but hirudin, a specific alpha-thrombin inhibitor, had negligible effect on bothrombin activity. Unlike alpha-thrombin, bothrombin split off fibrinopeptide A without releasing fibrinopeptide B. Bothrombin activated blood coagulation factor VIII, but its activity was about 950 times less than that of alpha-thrombin. Bothrombin did not induce aggregation or serotonin release of washed normal platelets by itself, but did aggregate platelets in the presence of exogenous fibrinogen. This latter activity was completely inhibited by either anti-glycoprotein (GP) IIb/IIIa monoclonal antibody (which blocks fibrinogen binding to GP IIb/IIIa) or anti-GP Ib monoclonal antibody (which specifically inhibits alpha-thrombin binding to GP Ib). Prostaglandin E1 (1 microM) and EDTA (10 mM) also abolished platelet aggregation without affecting clotting activity. Washed platelets from a patient with Bernard-Soulier syndrome did not respond to bothrombin even in the presence of exogenous fibrinogen, suggesting that the initial binding of bothrombin on platelets is GP Ib, but not a recently cloned thrombin receptor. The complete amino acid sequence of bothrombin was determined by analysis of (S)-pyridylethylated protein and peptides generated by digestion with cyanogen bromide and Achromobacter protease I, respectively. Bothrombin is composed of 232 amino acid residues and contains three Asn-linked oligosaccharide chains.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1994

Inhibition by aurintricarboxylic acid of von Willebrand factor binding to platelet GPIb, platelet retention, and thrombus formation in vivo.

Commercial aurintricarboxylic acid (ATA) was separated into molecular-weight (MW) fractions of < 210 to > 25,000, using gel permeation chromatography. Fractions with MW > 1,300 effectively inhibited both botrocetin-induced vWF and bovine vWF binding to fixed human platelets. These activities decreased with a MW > 17,000. Platelet retention for a human in vitro was reduced by ATA at 150 microM, as was that for rats ex vivo at 3 mg/kg. ATA prolonged tail transection bleeding time in rats but had only a weak effect on buccal mucosal bleeding time in dogs. ATA had no effect on platelet count but markedly prolonged PTT. ATA at 10 mg/kg exhibited antithrombotic activity and caused a marked improvement in patency status following successful thrombolysis by t-PA in electrically and copper coil-induced thrombosis models. These results suggest that specific inhibitors of the vWF-GPIb interaction such as ATA may prove useful as antithrombotic agents.

Animals↗
PubMed1994

C-type galactoside-binding lectin from Bothrops jararaca venom: comparison of its structure and function with those of botrocetin.

A Ca(2+)-dependent type (C-type) galactoside-binding lectin was purified from venom of the snake Bothrops jararaca by thiodigalactoside-Sepharose affinity column chromatography. B. jararaca lectin is a disulfide-linked homodimer composed of 14-kDa subunits. The N-terminal 55-residue amino acid sequence was determined and appeared to belong to the animal C-type lectin family. This 55-residue sequence showed 37% identity with botrocetin, an exogenous von Willebrand factor modulator purified from the same venom, and 85% identity with a lectin from rattlesnake (Crotalus atrox) venom. B. jararaca lectin showed Ca(2+)-dependent hemagglutination activity but did not induce platelet aggregation in the presence or absence of Ca2+ and von Willebrand factor and did not inhibit platelet aggregation induced by botrocetin and von Willebrand factor. On the other hand, botrocetin, which also contains a C-type lectin motif in the N-terminal sequence, did not show hemagglutinating activity toward rabbit and human erythrocytes, nor binding activity toward immobilized glycoproteins. These results indicate that at least two structurally similar but functionally distinct proteins, both belonging to the C-type lectin family, are present in the venom of B. jararaca.

Amino Acid Sequence↗
PubMed1994

Emergency operation for thoracic aortic aneurysm caused by the Ehlers-Danlos syndrome.

Two patients were treated emergently for impending ruptured thoracic aortic aneurysms caused by type IV Ehlers-Danlos syndrome. One patient had typical physical evidence of type IV Ehlers-Danlos syndrome. The other patient had a normal phenotype. Type IV Ehlers-Danlos syndrome was diagnosed by electrophoresis of the collagen extracted from the skin. The clinician must be aware of the variations in presentation of type IV Ehlers-Danlos syndrome.

Adolescent↗
PubMed1994

Changes in choline acetyltransferase distribution in the cervical spinal cord after reversible cervical spinal cord injury.

Reversible spinal cord injury (SCI) at C6 level in rats, produced by the weight-placed method, resulted in a severe motor functional deficit initially, followed by a gradual recovery. During the recovery, choline acetyltransferase (CAT) distribution in the cervical spinal cord was investigated at 2, 4, 7, 14 and 28 days after the injury by quantitative immunohistochemistry with a fluorescence microphotometry system. At C6 level, the fluorescence intensity of the ventrolateral anterior horn (VLAH), which reflected the concentration of CAT, decreased to approximately 50% of that of the sham-operated group at 2 days. It then recovered to 60% at 4 days after the injury, and remained unchanged thereafter. Fluorescence intensities in VLAH at C4-5 and C7-8 levels decreased to approximately 60-70% at 2 days after the injury, but it recovered and increased to 110-130% thereafter.

Animals↗
PubMed1994

Neurological evaluation after radical resection of sacral neoplasms.

Eight patients had a radical resection of sacral tumours, and bilateral severance of lumbosacral nerves was required. Their neurological deficits and disturbance of activities of daily living (ADL) were studied. The neurological deficits which occurred were motor dysfunction of the lower limbs, sensory disturbances, and urinary, faecal and sexual dysfunction. Bilateral preservation of the L5 nerve and above was necessary to permit the ability to walk, and bilateral preservation of the S2 nerve and above was necessary to spare urinary, faecal and sexual functions in order to establish ADL. To maintain normal ADL, bilateral preservation of the S2 nerve and above was necessary for walking, and bilateral preservation of the S3 nerve and above was necessary for urinary, faecal and sexual functions.

Activities of Daily Living↗
PubMed1994

The DNA replication fork blocked at the Ter site may be an entrance for the RecBCD enzyme into duplex DNA.

In Escherichia coli, eight kinds of chromosome-derived DNA fragments (named Hot DNA) were found to exhibit homologous recombinational hotspot activity, with the following properties. (i) The Hot activities of all Hot DNAs were enhanced extensively under RNase H-defective (rnh) conditions. (ii) Seven Hot DNAs were clustered at the DNA replication terminus region on the E. coli chromosome and had Chi activities (H. Nishitani, M. Hidaka, and T. Horiuchi, Mol. Gen. Genet. 240:307-314, 1993). Hot activities of HotA, -B, and -C, the locations of which were close to three DNA replication terminus sites, the TerB, -A, and -C sites, respectively, disappeared when terminus-binding (Tau or Tus) protein was defective, thereby suggesting that their Hot activities are termination event dependent. Other Hot groups showed termination-independent Hot activities. In addition, at least HotA activity proved to be dependent on a Chi sequence, because mutational destruction of the Chi sequence on the HotA DNA fragment resulted in disappearance of the HotA activity. The HotA activity which had disappeared was reactivated by insertion of a new, properly oriented Chi sequence at the position between the HotA DNA and the TerB site. On the basis of these observations and positional and orientational relationships between the Chi and the Ter sequences, we propose a model in which the DNA replication fork blocked at the Ter site provides an entrance for the RecBCD enzyme into duplex DNA.

Bacterial Proteins↗
PubMed1994

Immunohistochemical localisation of intercellular adhesion molecule-1 in follicle associated epithelium of Peyer's patches.

The epithelium covering domes of lymphoid follicles in Peyer's patches includes membranous cells, which are sites of entry for various macromolecules, absorptive cells, a few goblet cells, and many migrating lymphoid cells. The mechanism of migration of lymphoid cells into the follicle associated epithelium of lymphoid follicles in Peyer's patches is still unknown. This study investigated the relation between localisation of intercellular adhesion molecule-1 (ICAM-1) and the follicle associated epithelium of Peyer's patches immunohistochemically. It was found that subepithelial fibroblasts expressed ICAM beneath the follicle associated epithelium on lymphoid follicles, but not on surrounding villi. The results show that the massive lymphocytic traffic between follicle associated epithelium and lymphoid follicles may be related to ICAM-1 expression.

Animals↗
PubMed1994

[Quantitative flow-cytometric analysis of CD34-positive stem cells in peripheral blood stem cell harvests].

The percentage of CD34-positive cells (the CD34-positive rate) in peripheral blood stem cell harvests (PBSCH) was determined using two color flow cytometric methods, i.e., representation in a histogram (the histogram method) and the two-dimensional side scatter-fluorescence representation (the SSC-FL method). For all samples examined, the CD34-positive rate obtained using the histogram method was higher than that obtained using the SSC-FL method. This finding was probably due to the fact that some monocytes non-specifically reacted with anti-CD34 monoclonal antibody, and the histogram method could not distinguish these non-specifically stained cells from CD34-positive precursor cells. On the other hand, the SSC-FL method seemed to yield a more accurate measurement of the percentage of CD34-positive cells in PBSCH samples. Based on this finding, it is recommended that the histogram method, which is currently used at most commercial laboratories, be reviewed in favor of the SSC-FL method when the CD34-positive cell rate of PBSCH is to be determined.

Adolescent↗
PubMed1994

Sequential changes in stem cell markers in peripheral blood and leukapheresis samples after injections of recombinant human granulocyte colony-stimulating factor in patients with urogenital malignant solid tumors: a preliminary study.

In order to evaluate the mobilization effect of recombinant human granulocyte colony-stimulating factor (rhG-CSF) on peripheral blood stem cells (PBSCs), rhG-CSF was given to patients with urogenital malignancy before chemotherapy. Markers for the stem cells, such as colony forming unit-granulocyte/macrophage (CFU-GM) and burst forming unit-erythrocyte (BFU-E), were sequentially monitored in peripheral blood and leukapheresis samples. Five patients, including a 13-year-old boy, were given 5 micrograms/kg rhG-CSF subcutaneously: the pediatric case for four consecutive days and the adult cases for six consecutive days (53-72 years of age). None of the patients had received chemotherapy within the four weeks prior to the start of the rhG-CSF series. PBSC collections were performed on the fifth day in the pediatric case and on the fifth and seventh days in the adult cases. Progenitor cells were monitored by methyl-cellulose cell culture techniques. CFU-GM on day 5 of the rhG-CSF series in peripheral blood increased 14- to 53-fold compared with samples taken immediately before the series. CFU-GM in the leukapheresis products on day 5 was greatest (70 x 10(3)/kg) in the pediatric case and least (14 x 10(3)/kg) in the oldest patient's case. The totals of the CFU-GM collected by two phereses in the adult cases were 21-73 x 10(3)/kg and the totals of CD34 positive cells were 0.6 to 1.4 x 10(6)/kg. The data suggest rhG-CSF to induce sufficient PBSCs for bone marrow rescue into the peripheral blood without any preceding chemotherapy. The patient's age may, however, be a contributory factor in using this method.

Adolescent↗
PubMed1994

[An adult case of tethered cord syndrome with lipoma and thoraco-lumbar syringomyelia presenting slow progressive muscular atrophy in the lower limbs].

A 23-year-old man developed slowly progressive muscle weakness from the age of 10, followed by paresthesia and urinary disturbance. The physical examination showed bilateral muscular atrophy in the lower limbs and dissociated sensory disturbance below Th8. Although there was normal appearance of spinal X-P, MRI revealed conus medullaris at S2 involved thoraco-lumbar syringomyelia with extramedullary lipoma. After the operation for laminectomy of L5-S2 and untethering without direct surgery for syringomyelia, post-operated MRI exhibited definite shrinkage of the syrinx. It suggested that thoraco-lumbar syringomyelia in the present case was not congenital anomaly, but secondary outcome to tethered cord syndrome.

Adult↗
PubMed1994

[Significance of AKBR as an indicator of liver injury after cardiopulmonary bypass].

AKBR is a metabolic indicator related to NAD-linked dehydrogenase system, according to the REDOX theory. In order to estimate whether AKBR is a sensitive indicator of liver injury or not, we measured AKBR before and immediately after cardiopulmonary bypass (CPB) in 20 patients undergoing cardiac surgery and thoracic aortic aneurysmectomy. Twenty patients were divided into two groups: one with AKBR more than 0.7 (normal group) and the other with AKBR less than 0.7 (abnormal group). The AKBR in the abnormal group was significantly decreased after CPB (p < 0.05), though the AKBR in the normal group was unchanged. In addition, the normal group significantly showed high AKBR compared to the abnormal group after CPB (p < 0.01). Among 5 patients with GPT more than 50 IU/l, the number of patients with AKBR more than 0.7 was zero and with AKBR less than 0.7 was 5 patients. The normal group has a lower risk of liver injury than the abnormal group. The normal group had a higher hepatic perfusion pressure compared with abnormal group. However, there were not significant differences in the cardiac functions (cardiac output, LVSWI and RVSWI) after the CPB between two group, whereas the CPB time and the aortic clamping time in the abnormal groups were longer than those in the normal group. We concluded that the AKBR is a sensitive indicator of liver function after the CPB.

Cardiac Surgical Procedures↗
PubMed1994

[Influence of blood transfusion on cellular immunity after open heart surgery].

The effect of blood transfusion on cellular immunity was evaluated by measuring T cell subsets in 22 adult patients after open heart surgery. The patients were divided into two groups according to whether or not they received blood transfusions. There were no significant differences in pump time or aortic cross clamp time between the two groups. Leukocytosis was evident in both groups after open heart surgery, but the percentage to lymphocytes was reduced. The number of T cells were also reduced in both two groups. In the group that did not receive blood, the number of T cells were reduced the first day after surgery, but returned to preoperative levels two days later. Those that received blood transfusions had persistently low T cell counts three days after the operation. CD4 positive T cells were reduced the first day after operation but returned to preoperative levels three days after the operation in both groups. The percentage of CD8 positive T cells were unchanged in the group that didn't have a blood transfusion. CD8 positive T cells were significantly reduced three days post operatively in the group that received blood transfusions. The cellular immunity was disturbed for an extended period in the patients that received blood transfusions.

Adolescent↗
PubMed1994

[Aggressive management of prolapsed fetal membranes earlier than 26 weeks' gestation by emergent McDonald cerclage combined with amniocentesis and bladder overfilling].

During the period January, 1987-December, 1992, 32 pregnant women (33 fetuses) earlier than 26 weeks' gestation were admitted to our perinatal unit with incompetent cervix and prolapsed fetal membranes through the cervix (hourglassing). Eighteen pregnant women (19 fetuses) were managed aggressively with emergent double McDonald cerclage, which included preoperative amniocentesis and bladder overfilling to decompress and replace prolapsed fetal membranes. Fourteen pregnant women were managed conservatively with bed rest, tocolysis, and antibiotic therapy. The perinatal results of aggressive management were clearly more favorable than those of conservative management when compared: Prolongation of pregnancy 35.2 +/- 39.7 vs. 3.5 +/- 2.6 days (p < 0.01), gestational age at delivery 27.3 +/- 5.3 vs. 24.2 +/- 1.2 weeks' (p < 0.05), birth weight 1,260 +/- 909 vs. 690 +/- 124 grams (p < 0.05), and fetal salvage rates 74(14/19) vs. 7(1/14)%, respectively.

Amniocentesis↗