Search PubMed⌕ Search

Biomedical subjects

R Watanabe

Publications and source records attributed to R Watanabe.

At least 55 records · Page 3Linked to original sources
PubMed2000

Initial enzyme for glycosylphosphatidylinositol biosynthesis requires PIG-P and is regulated by DPM2.

Glycosylphosphatidylinositols (GPIs) are attached to the C-termini of many proteins, thereby acting as membrane anchors. Biosynthesis of GPI is initiated by GPI-N-acetylglucosaminyltransferase (GPI-GnT), which transfers N-acetylglucosamine from UDP- N-acetylglucosamine to phosphatidylinositol. GPI-GnT is a uniquely complex glycosyltransferase, consisting of at least four proteins, PIG-A, PIG-H, PIG-C and GPI1. Here, we report that GPI-GnT requires another component, termed PIG-P, and that DPM2, which regulates dolichol-phosphate-mannose synthase, also regulates GPI-GnT. PIG-P, a 134-amino acid protein having two hydrophobic domains, associates with PIG-A and GPI1. PIG-P is essential for GPI-GnT since a cell lacking PIG-P is GPI-anchor negative. DPM2, but not two other components of dolichol-phosphate-mannose synthase, associates with GPI-GnT through interactions with PIG-A, PIG-C and GPI1. Lec15 cell, a null mutant of DPM2, synthesizes early GPI intermediates, indicating that DPM2 is not essential for GPI-GnT; however, the enzyme activity is enhanced 3-fold in the presence of DPM2. These results reveal new essential and regulatory components of GPI-GnT and imply co-regulation of GPI-GnT and the dolichol-phosphate-mannose synthase that generates a mannosyl donor for GPI.

Amino Acid Sequence↗
PubMed2000

Requirement of PIG-F and PIG-O for transferring phosphoethanolamine to the third mannose in glycosylphosphatidylinositol.

Many eukaryotic proteins are anchored by glycosylphosphatidylinositol (GPI) to the cell surface membrane. The GPI anchor is linked to proteins by an amide bond formed between the carboxyl terminus and phosphoethanolamine attached to the third mannose. Here, we report the roles of two mammalian genes involved in transfer of phosphoethanolamine to the third mannose in GPI. We cloned a mouse gene termed Pig-o that encodes a 1101-amino acid PIG-O protein bearing regions conserved in various phosphodiesterases. Pig-o knockout F9 embryonal carcinoma cells expressed very little GPI-anchored proteins and accumulated the same major GPI intermediate as the mouse class F mutant cell, which is defective in transferring phosphoethanolamine to the third mannose due to mutant Pig-f gene. PIG-O and PIG-F proteins associate with each other, and the stability of PIG-O was dependent upon PIG-F. However, the class F cell is completely deficient in the surface expression of GPI-anchored proteins. A minor GPI intermediate seen in Pig-o knockout but not class F cells had more than three mannoses with phosphoethanolamines on the first and third mannoses, suggesting that this GPI may account for the low expression of GPI-anchored proteins. Therefore, mammalian cells have redundant activities in transferring phosphoethanolamine to the third mannose, both of which require PIG-F.

Amino Acid Sequence↗
PubMed2000

Two brothers with frontotemporal dementia and parkinsonism with an N279K mutation of the tau gene.

OBJECTIVE: To characterize the clinical diagnostic features, neuropathologic phenotype of tau deposition, and subunit structure of tau filaments in patients who had an asparagine-to-lysine substitution at codon 279 (the N279K missense mutation) of the gene for microtubule-associated tau protein. BACKGROUND: The N279K mutation is a causative genetic defect for pallidopontonigral degeneration in an American kindred that presents with frontotemporal dementia (FTD) and parkinsonism. METHODS: The authors analyzed retrospectively the clinical symptoms of two Japanese brothers who carry this mutation. Postmortem neuropathologic and electron microscopic studies, and Western blot analysis of insoluble tau were performed to correlate tau-mediated lesions with neurologic deficits. RESULTS: Both patients exhibited impairment in recent memory, parkinsonism, and corticospinal disturbances in addition to FTD. Parkinsonism in one patient was responsive temporarily to l-dopa. There was intense tau deposition in the medial temporal cortices and upper and lower motor neurons with accompanying corticospinal tract degeneration. Two distinct tau isoforms with four microtubule-binding repeats, in hyperphosphorylated forms, were the primary constituents of insoluble tau, which aggregated to the filamentous component, termed "paired tubules," in neurons, oligodendrocytes, and astrocytes. The elemental filaments were hollow tubules measuring 11 to 12 nm in diameter, two of which adhered to each other along their longitudinal axes to form "paired tubules." CONCLUSIONS: Early memory loss and pyramidal signs, which are atypical of FTD, can be presenting symptoms in this disorder. The authors demonstrated that the subunit structure of tau filaments is a pair of hollow tubules despite the prevailing twisted ribbon model.

Amino Acid Substitution↗
PubMed2000

The effect of age on inflammatory responses and nerve root injuries after lumbar disc herniation: an experimental study in a canine model.

STUDY DESIGN: An experimental investigation on the effect of age on pathologic events surrounding the herniated disc and at the adjacent nerve root. OBJECTIVES: To investigate the role of age on the inflammatory responses and nerve root damage surrounding a sequestered lumbar disc fragment using a dog model. SUMMARY OF BACKGROUND DATA: Lumbar disc herniation is manifested in patients by variable clinical findings, natural history, and resorption phenomena in which the variability is particularly noted among patients with different ages. There are no previous reports on the effect of age on pathologic events induced by the herniated disc. METHODS: Six beagle dogs, including two animals of each age group of 6, 12, and 24 months (human equivalent ages of 10, 15, and 24 years), were used in this study. The dogs underwent L4-L5, L5-L6, and L6-L7 laminotomy and discectomy under general anesthesia. An autologous intervertebral disc from the tail was divided into anulus fibrosus and nucleus pulposus fragments. The anulus fibrosus and nucleus pulposus fragments were placed in the anterolateral epidural space of L5-L6 and L6-L7, respectively. The L4-L5 discectomy site served as a control. Dogs were killed at 12 weeks after surgery. The lumbar spine was removed en bloc, and histologic sections were prepared consecutively and examined. RESULTS: In the nucleus pulposus group at L6-L7, neovascularity, and intensive infiltration of lymphocytes, macrophages, and fibroblasts were observed surrounding the nucleus pulposus fragment in the 24-month-old group only. Degenerative changes of the nerve root fibers were observed in the 24-month-old group only. In the control and anulus fibrosus groups at L4-L5 and L5-L6, there were no marked inflammatory reactions in all age groups. The nerve root fibers around the anulus fibrosus were normal in all age groups. CONCLUSIONS: There is an effect of age on the inflammatory response and nerve root injury caused by the herniated disc. The apparent neuroprotective mechanism in the young animal, and the apparent inflammatory and resorption changes of the nucleus pulposus fragment in the older animal are quite intriguing.

Aging↗
PubMed2000

Learning deficiency and alterations in acetylcholine receptors and protein kinase C in the brain of senescence-accelerated mouse (SAM)-P10.

The senescence-accelerated mouse (SAM) is known to be a murine model for accelerated aging. A novel inbred SAMP10 has shown age-related brain atrophy and learning deficiency. In the present study, we investigated the changes in learning ability and in ligand binding with muscarinic acetylcholine (mACh) receptors, alpha adrenoceptors and protein kinase C in SAMP10. In Morris's water maze task, in a control strain of SAMR1 at 9 months, the escape latency and path length decreased with increasing trial days, in contrast, escape latency and path length did not decrease in SAMP10. These results indicate that SAMP10 exhibits learning deficiency. The ligand binding activity of mACh receptors decreased in the hippocampus of SAMP10 and the protein kinase C level in the hippocampus of SAMP10 was lower than that of SAMR1. On the other hand, there was no significant difference between SAMR1 and SAMP10 regarding ligand binding activity of alpha(1) and alpha(2) adrenoceptors. Thus, a reduction of mACh receptors and protein kinase C in the brain seems to underlie dysfunction of learning and memory in SAMP10.

Aging, Premature↗
PubMed2000

The Japanese multicenter open randomized trial of ursodeoxycholic acid prophylaxis for hepatic veno-occlusive disease after stem cell transplantation.

Hepatic veno-occlusive disease (VOD) is a common transplant-related complication of stem cell transplantation. There is no safe and proven therapy for established VOD, and attempts have focused on its prevention. Limited studies have suggested that prophylactic use of ursodeoxycholic acid (UDCA) reduced the incidence of VOD. To confirm the preventive effect of UDCA on VOD, we conducted a prospective, unblinded randomized, multicenter study of UDCA involving 132 patients who underwent stem cell transplantation for a variety of disorders. Sixty-seven patients were assigned to the UDCA-treated group, and 65 patients were assigned to the control group. The clinical characteristics of the two groups were similar with respect to primary diagnosis, age, sex, and baseline organ function. The preparative regimen and GVHD prophylaxis did not differ significantly between the two groups. UDCA was highly effective in preventing VOD, which occurred in only 3.0% in the UDCA-treated group, as opposed to 18.5% in the control group (P = 0.0043). There were no adverse effects attributable to UDCA. The initial promising report of a prophylactic effect of UDCA on VOD after stem cell transplantation was confirmed in this prospective study.

Adult↗
PubMed2000

Decreased tissue factor and tissue-plasminogen activator antigen in relapsed acute promyelocytic leukemia.

This study evaluated hemostatic data in 28 patients with newly diagnosed acute promyelocytic leukemia (APL) and 15 patients with relapsed APL. Activated partial thromboplastin time and prothrombin time were prolonged at initial onset of APL. Plasma level of fibrinogen was significantly decreased in patients with initial disease of APL, but it was not decreased significantly during the relapse of APL. Plasma fibrin and fibrinogen degradation products levels were significantly increased and platelet counts significantly decreased in both groups. Plasma levels of antiplasmin significantly decreased at initial onset but not during relapse. Plasma levels of antithrombin were within normal range in patients with initial disease but significantly decreased in those with relapse. Plasma levels of D-dimer, soluble fibrin monomer (sFM), plasmin-plasmin inhibitor complex (PPIC), and thrombin antithrombin complex (TAT) levels were significantly high in both groups. Plasma levels of PPIC, sFM, and D-dimer were significantly higher at initial onset of APL than during relapse. However, there was no significant difference in DIC score between patients with initial onset and those with relapse; plasma levels of tissue factor (TF) significantly increased in both groups, but they were significantly higher at initial onset of APL than during relapse. TF and tissue type plasminogen activator (t-PA) antigen levels in leukemic cell lysate were significantly increased in both groups, and they were significantly lower during relapse than at initial onset. Hemostatic abnormalities occurring in patients with relapsed APL might be the result of the decrease of TF and t-PA in leukemic cells. These findings suggest that DIC in APL patients with relapse might not be caused only by TF and t-PA and thus should be treated with different therapy from patients with initial onset of APL.

Adolescent↗
PubMed2000

Plasma levels of activated protein C-protein C inhibitor complex in patients with hypercoagulable states.

Plasma levels of activated protein C (APC)-protein C inhibitor (PCI) were significantly increased in patients with disseminated intravascular coagulation (DIC), thrombotic thrombocytopenic purpura (TTP), acute myocardial infarction (AMI), pulmonary embolism (PE), or deep vein thrombosis (DVT) and in patients undergoing hemodialysis (HD). Plasma levels of APC-alpha(1)-antitrypsin (AT) complex were significantly increased in patients with DIC and in those with TTP. Plasma levels of PCI were significantly decreased in patients with DIC, non-DIC, or TTP and in those undergoing HD. In the pre-DIC stage, the plasma levels of APC-PCI complex were significantly increased but not those of APC-alpha(1)-AT complex. These data suggest that measurements of APC-PCI complex and APC-alpha(1)-AT complex may be useful for the diagnosis of DIC. After treatment of DIC, the plasma levels of APC-PCI complex and APC-alpha(1)-AT complex were significantly decreased, but not those of PCI. Plasma levels of thrombin-antithrombin complex (TAT), plasmin-alpha(2)-plasmin complex (PPIC), D-dimer, and soluble fibrin monomer (SFM) were markedly increased in patients with DIC or pre-DIC and were moderately increased in patients with non-DIC, TTP, AMI, PE, or DVT and in those undergoing HD. The receiving operating characteristic (ROC) analysis showed that SFM and the APC-PCT complex are useful markers for diagnosis of DIC. The specificity of plasma TAT and PPIC levels was low. The positive rate of APC-PCI complex was higher than 90% with DIC, TTP, AMI, PE, and it was higher than 60% with DVT and HD. Since the APC-PCI complex was elevated not only in patients with venous thrombosis but also in those with arterial thrombosis, components of the protein C pathway might be useful markers for the diagnosis of arterial thrombosis.

Antithrombin III↗
PubMed2000

Increased plasma levels of tissue factor pathway inhibitor-activated factor X complex in patients with disseminated intravascular coagulation.

Plasma levels of tissue factor pathway inhibitor (TFPI)-activated factor Xa (FXa) complex were measured in patients with disseminated intravascular coagulation (DIC), pre-DIC, and DIC. Plasma levels of plasmin-plasmin inhibitor complex (PPIC), D-dimer, and soluble fibrin monomer (SFM) were significantly higher in patients with DIC than in those with pre-DIC or non-DIC; the levels of these hemostatic markers were significantly higher in patients with pre-DIC than in those with non-DIC. Plasma levels of thrombin-antithrombin complex (TAT) were significantly higher in patients with DIC or pre-DIC than in those with non-DIC. Plasma levels of tissue factor (TF), total TFPI, free TFPI, and TFPI-Xa complex were significantly higher in patients with DIC than in those with non-DIC. Plasma levels of TFPI-Xa complex were significantly increased in patients with pre-DIC as compared to those with non-DIC; however, plasma free TFPI levels were significantly decreased in patients with pre-DIC as compared to those with non-DIC. These findings suggest that free TFPI might be consumed in the pre-DIC state, thereby confirming the activation of the extrinsic pathway. Plasma levels of TFPI-Xa complex were significantly correlated with TF, free TFPI, and total TFPI. Increased plasma TFPI-Xa complex levels might be useful for the diagnosis of DIC or pre-DIC, particularly that occurring by activation of the extrinsic pathway of blood coagulation.

Anticoagulants↗
PubMed2000

Long-term survival of transmural advanced gastric carcinoma following curative resection: multivariate analysis of prognostic factors.

Patients with transmural (T2N0-T3N2) advanced gastric carcinoma comprise the largest group with uncertain outcome. These patients must be stratified according to the prognostic variables so the high risk group can be precisely identified. A total of 152 patients with transmural advanced gastric carcinomas were uniformly treated with a curative intent between 1979 and 1989 with at least a 7-year follow-up. Results and prognostic factors of long-term survival were analyzed by univariate and multivariate analyses. Seventy-five (49%) patients with advanced gastric carcinoma survived more than 7 years, which indicates the curative nature of surgery for gastric carcinoma. Seventeen variables were evaluated by univariate analysis. In the multivariate analysis, patient's age [>70 years, relative risk (RR) 2.4)], intraoperative blood loss (>500 ml, RR 1.7), blood vessel invasion (RR 2.3), ratio of invaded dissected lymph nodes (>0.2, RR 3.0), and tumors penetrating the serosa (RR 3.9) were the independent prognostic variables. The results of this study indicate that extensive lymphadenectomy and minimal intraoperative blood loss might be helpful for improving patient survival following a curative resection. Patients with vessel invasion, serosal involvement, and those >70 years of age should be considered at high risk and require appropriate adjuvant therapy to prolong survival.

Adenocarcinoma↗
PubMed2000

Risk-adapted pre-emptive therapy for cytomegalovirus disease in patients undergoing allogeneic bone marrow transplantation.

We prospectively evaluated a risk-adapted pre-emptive treatment with ganciclovir for CMV diseases in patients undergoing allogeneic bone marrow transplantation (BMT). High-level CMV antigenemia (10 or more positive cells on two slides) or CMV antigenemia at any level in patients with grade II-IV acute graft-versus-host disease (aGVHD) were chosen as risk factors. We also retrospectively evaluated virus reactivation in plasma using quantitative real-time polymerase chain reaction (PCR). Fifty patients were evaluable. None of the 27 patients with or without grade I aGVHD developed high-level CMV antigenemia or CMV disease. Among the 23 patients with grade II-IV aGVHD, 12 patients (52%) developed CMV antigenemia and were treated pre-emptively, of whom two developed CMV gastroenteritis or retinitis in spite of therapy. Six of the remaining 11 patients developed CMV gastroenteritis before CMV antigenemia was detectable. All of the eight patients with CMV diseases were successfully treated with ganciclovir and no deaths directly related to CMV disease occurred. In four of the seven evaluable patients with CMV gastroenteritis, real-time PCR was able to detect virus reactivation earlier than CMV antigenemia. Although our risk-adapted pre-emptive therapy effectively reduced CMV-related mortality, further refinements of this approach, particularly in the prevention of CMV gastroenteritis, may be achieved by incorporating real-time PCR.

Adolescent↗
PubMed2000

Erythema exsudativum multiforme induced by granulocyte colony-stimulating factor in an allogeneic peripheral blood stem cell donor.

We describe a healthy peripheral blood stem cell (PBSC) donor who developed a cutaneous reaction, erythema exsudativum multiforme, during the administration of granulocyte colony-stimulating factor (G-CSF) for mobilization. The cutaneous lesions were located on his hips, apart from the site of G-CSF injection. Treatment with topical corticosteroid was commenced, and the lesions resolved completely within a week. Adverse cutaneous reactions induced by G-CSF have been reported infrequently in healthy donors. Further documentation of cases and their full evaluation will be of great importance for both physicians and PBSC donor.

Adrenal Cortex Hormones↗
PubMed2000

Collection of peripheral blood stem cells with granulocyte-colony-stimulating factor alone in testicular cancer patients.

BACKGROUND: High-dose chemotherapy with the transplantation of peripheral blood stem cells (PBSC) has been performed for the treatment of advanced testicular cancer patients. Recently, it has been reported that, in healthy donors, a large quantity of stem cells can be transferred to peripheral blood using granulocyte-colony-stimulating factor (G-CSF) alone. Therefore, it was decided to try to harvest PBSC from three patients having testicular cancers with G-CSF alone. METHODS: The three patients with testicular cancer were 26, 56 and 62-years-old. They had undergone five, two and three cycles of chemotherapy, respectively, but no radiation therapy. Granulocyte colony-stimulating factor was subcutaneously injected (250 microg) into each patient twice per day for 6 days. Peripheral blood stem cells were harvested for 3 days (days 4-6) and mononuclear cells (MNC), CD34-positive cells and colony-forming units of granulocyte-macrophage (CFU-GM) in PBSC collected by apheresis were measured. RESULTS: Apheresis showed that the total MNC count was 20.2 x 10(8)/kg (range, 10.6-25.9 x 10(8)/kg), the CD34-positive cell count was 0.98 x 10(6)/kg (range, 0.75-1.4 x 10(6)/kg) and the total CFU-GM count was 1.36 x 10(5)/kg (range, 0.25-3.0 x 10(5)/kg). CONCLUSION: After mobilization of peripheral blood stem cells with G-CSF alone, sufficient amounts of MNC were obtained from testicular cancer patients who had undergone chemotherapy several times. However, sufficient amounts of CD34-positive cells and CFU-GM could not be obtained. These results suggested that the G-CSF dose was not adequate for harvesting sufficient amounts of CD34-positive cells and CFU-GM.

Adult↗
PubMed2000

Interferon therapy for renal cell carcinoma in hemodialysis patients: report of two patients.

The method of interferon therapy has not been clarified in hemodialysis patients with renal cell carcinoma. Two hemodialysis patients with renal cell carcinoma were treated with natural interferon-alpha. The serum levels of interferon-alpha in both patients were measured after 24, 48, 72 and 96 h of injection. In case 1, the serum concentration of interferon-alpha after 24 h of injection at a dose of 3 x 10(6) reached a maximum and decreased gradually. In case 2, the serum concentration of interferon-alpha reached a maximum 24 h after injection at a dose of 3 x 10(6) and decreasing gradually after this. After an injection of interferon-alpha at a concentration of 6 x 10(6) 7 days later, the serum concentration of interferon-alpha reached a maximum 48 h after the injection and decreased gradually thereafter. The serum interferon-alpha concentrations of these cases were higher than normal renal function patients in other literature. It is necessary to modify the interval between injections for hemodialysis patients with renal cell carcinoma.

Antineoplastic Agents↗
PubMed2000

Extracorporeal shock wave lithotripsy for a ureteral stone in crossed fused renal ectopia.

BACKGROUND: A 63-year-old woman presented with right flank pain and macroscopic hematuria. RESULTS/METHODS: A plain film showed a calcific shadow on the right iliac bone. On excretory urography, the right kidney was seen in the normal position, but the left kidney was not. Bilateral retrograde pyelogram revealed the S-shaped kidney and mild obstruction from a 12 x 5 mm calculus in the proximal ureter of the crossed kidney. The patient was successfully treated with in situ extracorporeal shock wave lithotripsy (ESWL) treatment and is stone free at 1 month follow up. CONCLUSION: We believe this is the first case of successful ESWL in a crossed kidney.

Female↗
PubMed2000

Controlling malignant pericardial effusion by intrapericardial carboplatin administration in patients with primary non-small-cell lung cancer.

Malignant pericarditis, when associated with massive pericardial effusion, presents a critical condition in lung cancer patients. Because this condition often arises in terminally ill patients, intensive therapy such as multi-drug combination chemotherapy is rarely appropriate. This study evaluated the clinical relevance of intrapericardial administration of carboplatin for controlling malignant pericardial effusions associated with non-small-cell lung carcinoma (NSCLC). The method used for 10 eligible patients consisted of draining the pericardial effusion and infusing 300 mg/body of carboplatin in 50 ml of saline through an in-place catheter into the pericardial space and clamping the catheter for 40 min. Nine of the 10 patients showed satisfactory results, and 8 experienced complete regression of the effusion. No major or minor adverse effects were observed. Pharmacokinetics analysis revealed that the concentration of free platinum in the pericardial fluid was very high while that of total platinum in the circulating plasma was very low, assuring the usefulness of the intrapericardial instillation of carboplatin in terminally ill patients for controlling malignant pericardial effusion when the systemic delivery of cytotoxic agents is inappropriate.

Adenocarcinoma↗