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Biomedical subjects

H Yamauchi

Publications and source records attributed to H Yamauchi.

At least 127 records · Page 7Linked to original sources
PubMed1999

Significance of increased oxygen extraction fraction in five-year prognosis of major cerebral arterial occlusive diseases.

UNLABELLED: In major cerebral arterial occlusive diseases, patients with increased oxygen extraction fraction (OEF), which is measured with PET, may be at increased risk for cerebral ischemia. However, the clinical significance of increased OEF remains unclear. This study investigated whether increased OEF is an independent predictor of 5-y risk of subsequent stroke. METHODS: We prospectively evaluated the relationship between the regional hemodynamic status of cerebral circulation and the subsequent risk of stroke in 40 patients with symptomatic internal carotid or middle cerebral arterial occlusive diseases who underwent PET. Patients were divided into two hemodynamic categories according to the mean hemispheric value of OEF-in the hemisphere supplied by the artery with symptomatic disease: one group with increased OEF and one with normal OEF. All patients were followed for 5 y with medical treatment until the recurrence of stroke or death. RESULTS: During 5 y, 11 total and 9 ipsilateral ischemic strokes occurred. The incidences of all ischemic strokes in patients with increased OEF and in those with normal OEF were 5 of 7 and 6 of 33 patients, respectively. There were 4 ipsilateral ischemic strokes in patients with increased OEF and 5 in those with normal OEF. Kaplan-Meier analysis revealed that the risks of all stroke and ipsilateral ischemic stroke in patients with increased OEF were significantly higher than in those with normal OEF (log-rank test; P<0.0002 and P<0.0018, respectively). Multivariate analysis with the Cox proportional hazards model showed that increased OEF significantly increased stroke recurrence: the relative risk was 7.2 (95% confidence interval [CI], 2.0-25.5; P<0.005) for all stroke and 6.4 (95% CI, 1.6-26.1; P<0.01) for ipsilateral stroke. An increase in the absolute OEF value was a better predictor of recurrent ischemic stroke than was OEF asymmetry. CONCLUSION: These findings suggest that an increased OEF is an independent predictor of 5-y risk of subsequent stroke. Identification of patients with increased OEF may have clinical significance in preventing recurrent stroke.

Adult↗
PubMed1999

[Optimal timing of granisetron administration for the prevention of carboplatin-induced acute emesis].

This prospective pilot study was undertaken to determine whether delayed administration of one of the serotonin-receptor antagonists (granisetron) reduced carboplatin--induced emesis. The subjects were patients who were scheduled to undergo at least three courses of carboplatin based chemotherapy, in whom acute emesis occurred at the first course. Granisetron was administered therapeutically for the first course. Conventional prophylactic granisetron was given 30 min before carboplatin administration for the second course. For the third course, granisetron was administered 5 hr after completion of carboplatin administration. The degrees of appetite loss, nausea and frequency of vomiting on the Day 1 were compared between the three courses. Thirteen patients were evaluated. Acute emesis occurred 8 +/- hr after completion of carboplatin administration in the first courses of these patients. The degree of nausea and frequency of vomiting were reduced by administrating the granisetron five hours after carboplatin when compared with therapeutic granisetron administration or administration 30 min before carboplatin. The degree of appetite loss was significantly lowered by administering the granisetron 5 hr after carboplatin administration. Administration of granisetron 5 hr after carboplatin may thus lessen carboplatin-induced emesis more than conventional granisetron administration. A large-scale comparative study is warranted.

Acute Disease↗
PubMed1999

Successful therapy of myelodysplastic syndrome with menatetrenone, a vitamin K2 analog.

Although vitamin K2 is an inducer of the in vitro differentiation of myeloid leukemic cell lines, its clinical efficacy in the treatment of myelodysplastic syndrome (MDS) is unclear. We administered a vitamin K2 analog, menatetrenone, at 45 mg daily to an 80-year-old woman with MDS (refractory anemia) heavily dependent on red-cell transfusions. The patient's pancytopenia gradually improved, and she became transfusion-independent after 14 months. Pancytopenia recurred when menatetrenone was discontinued but recovered again with readministration. Administration of menatetrenone at a dose effective in improving osteoporosis may also be useful in restoring hematopoiesis in MDS patients, possibly by way of inducing differentiation.

Aged↗
PubMed1998

Constitutive and induced IL-18 receptor expression by various peripheral blood cell subsets as determined by anti-hIL-18R monoclonal antibody.

Interleukin-18 (IL-18) was identified as a molecule that induces IFN-gamma production and enhances NK cell cytotoxicity. Characterization of the receptor for human IL-18 (hIL-18R) is important for investigating the physiological role of IL-18 in nature. In the present study, we describe a monoclonal antibody (mAb) against hIL-18R (mAb No. 117-10C). This mAb inhibited the binding of 125I-labeled hIL-18 to IL-18R-expressing L428 cells. This mAb also neutralized hIL-18-induced T helper 1 type cytokine (IFN-gamma and GM-CSF) production by Con A-stimulated PBMC. PBMC were examined for the expression of IL-18R by two-color flow cytometry. Most CD19(+) B cells and a percentage of CD8(+) T cells were found to constitutively express IL-18R. Treatment of PBMC with IL-12 preferentially induced IL-18R expression on CD56(+) NK cells regardless of costimulation with mitogen. IL-18R expression on CD4(+) T cells was induced weakly by IL-12 treatment and moderately by PHA stimulation. However, neither could IL-12 treatment nor PHA stimulation induce IL-18R expression on CD8(+) T cells. Costimulation with both IL-12 and PHA was necessary for optimal IL-18R expression on CD8(+) T cells as well as on CD56(+) NK cells, CD4(+) T cells, and CD19(+) B cells. These results support the growing number of reports showing that IL-18 has modulatory effects on T, B, and NK cells.

Animals↗
PubMed1998

Neural activity during attention shifts between object features.

To investigate the neural mechanisms involved in shifting attention we used positron emission tomography to examine regional cerebral blood flow (rCBF) during a task that demands shifting attention between color and shape. Significant activation was observed in the right dorsal prefrontal cortex and parieto-occipital cortex at all frequencies of attention shifts. The frequency of shifts between categories correlated significantly with rCBF in the rostral part of the supplementary motor area and the left precuneus, whereas the number of successive correct responses correlated with rCBF in the orbitofrontal cortex and the caudate nucleus. This study suggests that several prefrontal regions may participate in the processes of shifting attention in different ways.

Adult↗
PubMed1998

Establishment of the cells useful for murine interleukin-18 bioassay by introducing murine interleukin-18 receptor cDNA into human myelomonocytic KG-1 cells.

We genetically engineered human myelomonocytic KG-I cells by introducing cDNA of murine interleukin-18 receptor (MuIL-18R) and established human cells which were capable of responding to MuIL-18. These cells expressed larger number of MuIL-18R (> 13,000 sites/cell) than intrinsic human IL-18 receptor (HuIL-18R) (< 2,500 sites/cell). And the cells responded to MuIL-18 as well as to HuIL-18 in a dose-dependent manner, and produced large amounts of interferon-gamma (IFN-gamma). We could estimate the amount of murine IL-18 based on the amounts of IFN-gamma produced by these cells. The stoichiometry was observed up to 150 ng/ml of MuIL-18. By using these cells, a large amount of MuIL-18 (448 +/- 89.2 ng/ml) was detected in sera of Propionibacterium acnes (P. acnes)/lipopolysaccharide (LPS)-treated endotoxic mice (the same conditions in which IL-18 was first identified). These cells provide us with a useful tool for determining the bioactivity of MuIL-18.

Animals↗
PubMed1998

Inhibition of ascorbate peroxidase under oxidative stress in tobacco having bacterial catalase in chloroplasts.

To analyze the potential of the active oxygen-scavenging system of chloroplasts, we introduced Escherichia coli catalase into tobacco chloroplasts. Photosynthesis of transgenic plants was tolerant to high irradiance under drought conditions, while the wild plants suffered severe damage in photosynthesis under the same conditions. Irrespective of responses to the stress, ascorbate peroxidase was completely inactivated both in the transgenic and wild-type plants. These findings are contrary to the established idea that the ascorbate peroxidase-mediated antioxidative system protects chloroplasts from oxidative stress.

Ascorbate Peroxidases↗
PubMed1998

Suppression of cell proliferation and the expression of a bcr-abl fusion gene and apoptotic cell death in a new human chronic myelogenous leukemia cell line, KT-1, by interferon-alpha.

A new human leukemia cell line, KT-1, was established from a patient in the blastic crisis phase of chronic myelogenous leukemia (CML). This cell line had a positive reaction for intracytoplasmic myeloperoxidase and two Philadelphia chromosomes (Ph1) [t(9;22)(q34;q11)] and lacked normal copies of chromosomes 9 and 22. Molecular characterization of the breakpoint in the t(9;22)(q34;q11) showed that KT-1 had a bcr-2/abl-2 splice junction. When the KT-1 cells were cultured with interferon (IFN)-alpha or IFN-gamma, the growth of the cells were dose-dependently suppressed. IFN-alpha and IFN-gamma exerted synergistic suppressive effects on the growth of KT-1 cells. Furthermore, IFN-alpha suppressed the expression of the bcr-abl fusion gene in KT-1 cells, and induced G1 cell-cycle arrest and apoptotic cell death. The KT-1 cell line should be a valuable tool for studying the molecular mechanism of the suppression of Ph1 clone cells from CML by IFN.

Apoptosis↗
PubMed1998

Atrophy of the corpus callosum, cortical hypometabolism, and cognitive impairment in corticobasal degeneration.

OBJECTIVE: To investigate whether atrophy of the corpus callosum is associated with cognitive impairment and cerebral cortical hypometabolism in corticobasal degeneration. DESIGN: Prospective clinicoradiological correlation with magnetic resonance imaging and positron emission tomography. SETTING: A university hospital. PATIENTS: Eight right-handed patients with clinically diagnosed corticobasal degeneration (mean+/-SD age, 64+/-8 years). MAIN OUTCOME MEASURES: Midsagittal corpus callosum area-skull area ratio (on T1-weighted magnetic resonance images), the sum of the scaled scores of the 6 subtests on the Wechsler Adult Intelligence Scale-Revised (Digit Span, Arithmetic, Picture Arrangement, Object Assembly, Block Design, and Digit Symbol), and cerebral metabolic rate of glucose (measured with positron emission tomography by using fludeoxyglucose F 18 as a tracer). RESULTS: Compared with 36 age-matched right-handed control subjects, the patients had significantly decreased callosal area-skull area ratio. The reduction in this ratio was greatest in the middle half of the corpus callosum. The atrophy of the corpus callosum was accompanied by a decreased mean cortical glucose metabolic rate with hemispheric asymmetry and a decrease in the sum of the scaled subtest scores of the Wechsler Adult Intelligence Scale-Revised. CONCLUSIONS: Atrophy of the corpus callosum with middle predominance is present in corticobasal degeneration, and this atrophy is associated with cognitive impairment and cerebral cortical hypometabolism with hemispheric asymmetry. Atrophy of the corpus callosum might reflect the severity of the disconnection between cortical regions, and this may be an important factor in the development of cerebral cortical dysfunction in corticobasal degeneration.

Aged↗
PubMed1998

Production of functional IL-18 by different subtypes of murine and human dendritic cells (DC): DC-derived IL-18 enhances IL-12-dependent Th1 development.

IL-18 is a recently described cytokine that shares biological activities with IL-12 in driving the development of Th1-type T cells. As dendritic cells (DC) are very potent inducers of T cell proliferation and differentiation we wondered whether they utilize IL-18 as a factor driving Th1 development. We demonstrate by Northern blot and reverse transcription-PCR that various subtypes of human and murine DC as well as the DC-line XS contain IL-18 mRNA. When supernatants of either enriched Langerhans cells (LC) or bone marrow-derived DC were analyzed for production of IL-18 protein, IL-18 production was detected in an IL-18-specific ELISA. To assess whether the IL-18 protein released by DC is functional, we performed a sensitive bioassay using the IL-18-dependent stimulation of concanavalin A-stimulated T cells. Both, supernatants from bone marrow-derived DC and enriched LC induced IFN-gamma production in the T cells. This production was partially inhibitable by addition of anti-IL-18 antiserum. In a TCR-transgenic mouse system we further demonstrate that DC-derived IL-18 potentiates IL-12-dependent Th1 development. Using DC derived from IL-12 knockout animals, we show that DC-derived IL-18 by itself is not capable of inducing Th1 cell differentiation. Together the data demonstrate that subtypes of DC are able to release functional IL-18 that is able to induce IFN-gamma production and Th1 differentiation in primed T cells.

Animals↗
PubMed1998

Changes in immune-endocrine response after surgery.

The authors evaluated the relationship between hormonal and cytokine responses after surgery. Patients who underwent thoracic oesophagectomy (O group; n = 7), pulmonary lobectomy (P group; n = 5), modified mastectomy (M group; n = 5) and laparoscopic cholecystectomy (LC group; n = 7), were randomly selected. Circulating neutrophil and lymphocyte numbers were assayed. Changes in the concentration of the hormones [adrenocorticotrophic hormone (ACTH), cortisol, and antidiuretic hormone (ADH)] and cytokines [tumour necrosis factor alpha (TNF-alpha), interleukin 1 beta (IL-1 beta), IL-6, and IL-10] were analysed. In O and P groups, neutrophils were still seen on post-operative day (POD) 3, while the leukocyte counts of M and LC groups returned to normal. The number of lymphocytes significantly decreased on POD1 and POD3 only after oesophagectomy. The pattern of hormonal levels was consistent in all groups. While TNF-alpha and IL-1 beta were undetectable in the peripheral blood, the concentration of IL-6 and IL-10 increased in O and P groups, but not in M and LC groups. The degree of lymphocytepenia and neutrophilia correlated well with the extent of surgical trauma.

Adrenocorticotropic Hormone↗
PubMed1998

Relationship between peritoneal washing cytology through implantable port system (IPS-cytology) and second-look laparotomy in ovarian cancer patients with unmeasurable residual diseases.

OBJECTIVE: Intraperitoneal chemotherapy for minimal residual ovarian cancer has been shown to be effective. However, evaluation of the response without a second-look laparotomy (SLL) is impossible because such disease is unmeasurable by radiographic studies. In this prospective pilot study, we evaluated the relationship between implantable port system (IPS)-cytology and findings by SLL in patients with unmeasurable diseases. METHODS: Patients eligible for this study were those who had either unmeasurable residual disease at the time of initial surgery or measurable residual disease which became unmeasurable before second-look laparotomy. At the time of the initial surgery, the IPS was placed and intraperitoneal chemotherapy was administered. To obtain IPS-cytology, approximately 500 ml of saline was infused, with the patients changing their position to wash the peritoneal surface as thoroughly as possible. More than 20 ml of saline was recovered for cytological evaluation. SLL was performed after 4 to 10 courses of chemotherapy. Results of IPS-cytology obtained immediately before SLL and the SLL findings were compared. RESULTS: Forty-four patients were entered into this study. Twenty-nine patients had unmeasurable residual disease at the time of initial surgery and 15 had measurable residual disease which became unmeasurable before SLL. Only 40 patients were eligible for evaluation because catheter failure occurred in 4 patients. Three of the 26 patients who had negative IPS-cytology results were found to have positive SLL results. All 14 patients who had positive IPS-cytology results also had positive SLL results. CONCLUSIONS: IPS-cytology can detect intraperitoneal persistent disease in patients with unmeasurable residual ovarian cancer. Persistent positive IPS-cytology can indicate a negative response to chemotherapy, thus making it possible to avoid SLL. Further study with a larger number of patients is required to determine the role of negative IPS-cytology.

Adult↗
PubMed1998

Determinants of postoperative and long-term survival of patients with ruptured abdominal aortic aneurysms.

To compare the surgical results of patients with ruptured (rAAA) and nonruptured abdominal aortic aneurysms (NrAAA), 267 consecutive patients surgically treated for abdominal aortic aneurysms (AAA) were reviewed. The patients' characteristics, preexistent risk factors, perioperative factors, and postoperative early and long-term survival were compared between the rAAA group (n = 27) and the NrAAA group (n = 240). A multivariate analysis to predict postoperative survival was also conducted in the rAAA group. The hospital mortality rate was 3.3% (8/232) for the NrAAA group and 22.2% (6/27) for the rAAA group (P < 0.001). The maximum size of aneurysms, period of preoperative hypotension, and intraoperative bleeding volume were significantly higher in the rAAA group than in the NrAAA group. The 5- and 10-year cumulative survival rates in the rAAA group were 88.1% and 42.0%, which were comparable to those in the NrAAA group. The incremental risk factors for hospital death in the rAAA group included advanced age, preoperative hypotension (< 80 mmHg), and postoperative renal failure requiring dialysis. These findings showed that the interval from rupture to cross-clamping must be shortened, maintaining hemodynamic stability to avoid prolonged hypotension. Reducing risk factors and minimizing deterioration of organ functions postoperatively would be essential to improve the prognosis of patients with rAAA.

Aged↗
PubMed1998

[Surgical treatment for perforated aorta caused by mediastinitis after bidirectional Glenn shunt and closure of atrial septal defect--a case report].

A 24-year-old man with Ebstein anomaly underwent a bidirectional Glenn shunt and closure of an atrial septal defect. Postsurgical prulent mediastinitis was treated by irrigation and drainage, but was followed by rupture of the ascending aorta. During emergency surgery, hypothermic circulatory arrest became necessary due to massive bleeding. Since he had undergone a bidirectional Glenn shunt, left heart venting was essential to obtain deep hypothermic circulatory arrest without cardiac distention and was successfully performed via an anterior thoracotomy approach. The perforated site of the ascending aorta was repaired with a Xeromedica patch. The anterior mediastinum was wrapped with the omentum. Transthoracic left heart venting via an anterior thoracotomy is an useful approach when hypothermic circulatory arrest is required to perform a median sternotomy and to approach the heart.

Adult↗
PubMed1998

Emergent bronchofiberoptic bronchial occlusion for intractable pneumothorax with severe emphysema.

Emergent bronchofiberoptic bronchial occlusion using fibrin glue and woven polyglycolic acid mesh for persistent pneumothorax with severe emphysema is described. A 74-year-old man who had severe pulmonary dysfunction accompanying chronic emphysema was admitted with a complaint of sudden severe dyspnea. The chest X-ray on admission revealed collapse of the right lung. The patient was placed on a mechanical ventilator because of acute respiratory failure. In spite of continuous suction through a chest drainage tube, air leakage persisted. On the seventh hospital day, subcutaneous emphysema was apparent in the face and scrotum in addition to the chest. First, a double-lumen catheter was inserted into the right B5 bronchus, and fibrin glue was infused into the drainage bronchus via the double-lumen catheter. However, the procedure failed. Next, a combination of fibrin glue and woven polyglycolic acid mesh which had been cut into small pieces was introduced and pushed into the B5 bronchus using forceps. The air leakage stopped immediately after the administration. This procedure is simple and a minimally invasive method for the treatment of intractable pneumothorax in a compromised patient on a mechanical ventilator.

Aged↗
PubMed1998

Symptomatic liver cyst: special reference to surgical management.

We conducted a retrospective study of 14 patients with symptomatic liver cysts to evaluate current therapeutic interventions for this condition. Abdominal pain (n = 7) or abdominal mass (n = 5) were the most frequent presentations. Three patients also had renal cyst. Percutaneous aspiration with ethanol sclerotheraphy was carried out in 4 patients and all cysts so treated diminished in size, with relief of the symptoms. One patient was treated by aspiration only and re-retension occurred. Cystectomy was performed in 2 patients, unroofing in 5, and fenestration in 2 patients. All patients gained relief of symptoms, with no recurrence of symptoms. Computed tomography revealed that the cysts were diminished or were no longer observable after all the treatments. Our experience indicates that unroofing, fenestration, and cystectomy are safe and suitable procedures for treatment of the condition. Ethanol sclerotherapy may be a feasible alternative to surgical intervention in selected patients.

Adult↗
PubMed1998

Effect of a specific synthetic inhibitor of neutrophil elastase (ONO-5046) on the course of acute hemorrhagic pancreatitis in dogs.

In acute pancreatitis, particularly in severe cases, polymorphonuclear neutrophil (PMN) elastase induces tissue damage in remote organs such as the lung, as well in the pancreas itself. Therefore, we examined the therapeutic effect of a specific synthetic inhibitor of PMN elastase (ONO-5046: Ono Pharmaceuticals, Osaka, Japan) on the lung, liver, and kidney, as well as pancreas, in severe hemorrhagic pancreatitis in dogs. Acute hemorrhagic pancreatitis was induced by the injection of a mixture of autologous bile and porcine trypsin into the main pancreatic duct. Lipopolysaccharide (LPS) was administered intravenously as a septic challenge. Two animal groups were used. In one group, continuous infusion of ONO-5046 was started prior to the injection of LPS (ONO group). In the other group (control), saline was infused instead. At the end of the experiment (330 min after the injection of bile and trypsin), the pancreas revealed severe hemorrhagic pancreatitis, and a large amount of bloody ascites had accumulated in the peritoneal cavity. The white blood cell count was markedly reduced in response to the induction of pancreatitis, and was decreased further by the septic attack, irrespective of the administration of ONO-5046, although the count increased again in the ONO group. Serum levels of amylase and alpha2-macroglobulin-trypsin complex increased similarly in both groups following administration of bile and trypsin. Serum Ca levels decreased in both groups. At the end of the experiment, the wet weight of the lung was slightly higher in the control group (without ONO-5046). Microscopically, the pancreas showed severe hemorrhage accompanied by extensive interstitial edema in both groups. The lung and liver demonstrated mild infiltration of inflammatory cells in the interstitium in both groups, although the inflammatory change in the liver was slightly milder in the ONO group. These findings indicate that severe hemorrhagic pancreatitis cannot be alleviated by the administration of a specific inhibitor of PMN elastase alone, although this may lessen damage to remote organs such as the liver and lung. The white blood cell count decreased markedly after the induction of acute pancreatitis, and much more after a septic challenge. This seems to be closely related to the accumulation of bloody ascites in the peritoneal cavity.

Amylases↗