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Biomedical subjects

M Hanada

Publications and source records attributed to M Hanada.

At least 19 recordsLinked to original sources
PubMed2002

[Assessment of saphenous vein grafts flow by Doppler echocardiography].

In an effort to evaluate flow characteristics of the saphenous vein grafts (SVG) after coronary artery bypass grafting, we performed duplex scanning of SVG which were anastomosed to the left anterior descending artery in 12 patients, and compared those indexes with 34 internal thoracic artery grafts (ITAG). The SVG were observed with a 7.5 MHz duplex scanner through the anterior intercostal space. The diameter of the vessel, systolic peak velocity, and diastolic peak velocity were recorded in both groups, and systolic flow volume, diastolic flow volume, and velocity ratio were calculated. The systolic and diastolic peak velocity of SVG were predominantly lower than ITAG. No difference in the diameter and flow ratio could not be demonstrated between 2 groups. The flow volume of SVG were also predominantly lower than that of ITAG throughout cardiac cycle. This study reveals that advanced stenotic change were caused in the SVG group and suggest the occurrence of vein grafts disease long after coronary artery bypass grafting.

Aged↗
PubMed2001

[Assessment of left internal thoracic artery graft by exercise Doppler echocardiography].

Doppler echocardiography has several advantages such as frequent use, noninvasive approach, and physiological evaluation. Supine bicycle exercise testing was conducted for 30 patients undergoing CABG with LITA to LAD. Doppler echocardiography studies were performed before and after exercise to observe the change. On the basis of the angiographic data, patients were divided into two groups: 27 patients with a patent LITA graft, 3 patients with mildly stenosed LITA graft. In the patients who had patent grafts, diastolic flow velocity were increased higher than systolic after exercise. In the stenotic group, the flow pattern was changed to further systolic one. Doppler echocardiography during exercise is thought to be a reliable method to assess the LITA flow.

Adult↗
PubMed2000

Regulation of the TAK1 signaling pathway by protein phosphatase 2C.

Protein phosphatase 2C (PP2C) is implicated in the negative regulation of stress-activated protein kinase cascades in yeast and mammalian cells. In this study, we determined the role of PP2Cbeta-1, a major isoform of mammalian PP2C, in the TAK1 signaling pathway, a stress-activated protein kinase cascade that is activated by interleukin-1, transforming growth factor-beta, or stress. Ectopic expression of PP2Cbeta-1 inhibited the TAK1-mediated mitogen-activated protein kinase kinase 4-c-Jun amino-terminal kinase and mitogen-activated protein kinase kinase 6-p38 signaling pathways. In vitro, PP2Cbeta-1 dephosphorylated and inactivated TAK1. Coimmunoprecipitation experiments indicated that PP2Cbeta-1 associates with the central region of TAK1. A phosphatase-negative mutant of PP2Cbeta-1, PP2Cbeta-1 (R/G), acted as a dominant negative mutant, inhibiting dephosphorylation of TAK1 by wild-type PP2Cbeta-1 in vitro. In addition, ectopic expression of PP2Cbeta-1(R/G) enhanced interleukin-1-induced activation of an AP-1 reporter gene. Collectively, these results indicate that PP2Cbeta negatively regulates the TAK1 signaling pathway by direct dephosphorylation of TAK1.

Adaptation, Biological↗
PubMed2000

Botryoid Wilms tumor: case report and review of literature.

A rare case of botryoid Wilms tumor is presented. The main clinical manifestations were persistent low-grade fever, malaise, and proteinuria associated with microhematuria. Ultrasonography revealed an echogenic mass in the right kidney, and a contrast-enhanced mass was found in the dilated collecting system by contrast-enhanced computed tomography. The surgically resected tumor was a polypoid, light-yellow, glistening mass that occupied a large part of the renal pelvis and originated from the pelvicaliceal wall. Part of the tumor extended to the proximal ureter, resulting in hydronephrosis in the involved kidney. No parenchymal lesion was observed. Microscopic examination revealed epithelial, stromal, and blastemal components, which indicated Wilms tumor. Infection had occurred in the hydronephrotic kidney, which presumably had caused the major presenting symptoms. The prognosis of our patient and previously reported cases of botryoid Wilms tumor was good compared with that of typical Wilms tumor, since the botryoid type can be detected at an early stage.

Hematuria↗
PubMed2000

Effects of roll and pitch components in retinal flow on heading judgement.

We investigated effects of roll (rotation around line of sight) and pitch (rotation around the horizontal axis) components of retinal flow on heading judgement from visual motion information. It was found that performance level of human observers for yaw (rotation around the vertical axis) plus pitch is little different from that for only yaw although there is bias in perceived heading toward the fixation point, and that heading judgement is fairly robust with respect to roll. It was also found that there are some observers who can perceive heading with pitch, yaw and roll at a roll rate of 11.5 degrees /s without extra-retinal information. It suggests that there exist compensation mechanisms for roll in the human visual system.

Algorithms↗
PubMed2000

Heading judgement from second-order motion.

We examined human heading judgement from second-order motion which was generated by random-dots with the contrast polarity determined randomly on each frame. It was found that human observers can judge heading fairly accurately from second-order motion when pure translation is simulated or when self-motion toward a ground plane with gaze rotation is simulated but they cannot when self-motion toward cloud-like random dots with gaze rotations is simulated. It is suggested that the human visual system cannot decompose the flow fields into rotational and translational components by using second-order motion information alone, but it can do in some ways from the flow field of the ground plane.

Contrast Sensitivity↗
PubMed2000

A model of human heading judgement in forward motion.

We developed a new computational model of human heading judgement from retinal flow. The model uses two assumptions: a large number of sampling points in the flow field and a symmetric sampling region around the origin. The algorithm estimates self-rotation parameters by calculating statistics whose expectations correspond to the rotation parameters. After the rotational components are removed from the retinal flow, the heading direction is recovered from the flow field. Performance of the model was compared with human data in three psychophysical experiments. In the first experiment, we generated stimuli which simulated self-motion toward the ground, a cloud or a frontoparallel plane and found that the simulation results of the model were consistent with human performance. In the second and third experiment, we measured the slope of the perceived versus simulated heading function when a perturbation velocity weighted according to the distance relative to the fixation distance was added to the vertical velocity component under the cloud condition. It was found that as the magnitude of the perturbation was increased, the slope of the function increased. The characteristics observed in the experiments can be explained well by the proposed model.

Computer Simulation↗
PubMed2000

Method for recovery of heading from motion.

A new method for recovery of heading from motion is developed on the basis of Longuet-Higgins and Prazdny's algorithm [Proc. R. Soc. London Ser. B 208, 385 (1980)]. In the algorithm a radial virtual flow field is generated and the difference between the original velocity field and the virtual radial field is computed. The difference vectors, which are directed to the heading point in the projected plane, allow us to estimate the direction of heading. The simulations of the algorithm were performed, and it was shown that the method estimates the direction of heading accurately.

Algorithms↗
PubMed2000

[Bone marrow transplantation-associated thrombotic microangiopathy manifested by visual disturbance].

In October 1996, a 26-year-old woman was given a diagnosis of acute myeloblastic leukemia, FAB subtype M1. Treatment with combined chemotherapy achieved a complete remission (CR). In May 1997, the patient received an allogenic bone marrow transplant (BMT) from an HLA-identical sibling donor. Cyclosporine (CsA) and short-term methotrexate were given for graft-versus-host disease (GVHD) prophylaxis. Successful engraftment was obtained and signs of acute or chronic GVHD never developed. Five months after BMT, the patient experienced low-grade fever and blurred vision. Retinal examination demonstrated intraretinal hemorrhages, cotton-wool spots, and retinal detachments, which were presumably attributable to multiple thrombosis of retinal microvessels. The patient also exhibited hemolytic anemia with red cell fragmentation, thrombocytopenia, elevated lactate dehydrogenase, and renal impairment, and was thus given a diagnosis of BMT-associated thrombotic microangiopathy (BMT-TM). Discontinuation of CsA and administration of ticlopidine and prednisolone induced successful recovery from BMT-TM. Three months after the onset of BMT-TM, however, the patient experienced generalized clonic-tonic seizures with consciousness loss. Single-photon-emission computed tomography revealed blood-flow disturbances in the brain, suggesting the recurrence of microthrombosis. Accordingly, multiple transfusions of fresh frozen plasma were administered together with dipyridamole and aspirin. The patient gradually recovered and remained asymptomatic through the following 13 months. Currently, early diagnosis of BMT-TM is considered to be difficult. We suggest that careful examination of the ocular base may be useful for the early detection of BMT-TM.

Adult↗
PubMed2000

The effect of modified ultrafiltration in pediatric open heart surgery.

Since 1997 we have performed modified ultrafiltration (MUF) in pediatric open heart operations. To elucidate the clinical effects of MUF, patients under 20 kg in weight who underwent corrective open heart operation since 1997 are divided into 2 cohorts according to the enforcement of MUF (control group versus MUF group) retrospectively. Procedures, age, bodyweight, cardiopulmonary bypass (CPB) time, operation time, amount of donor blood use, postoperative inotrope dose, postoperative intubation time, and postoperative gas exchange capacity of lung expressed with respiratory index (RI) were compared between groups. Furthermore, a multiple linear regression analysis was performed to find independent correlates with postoperative RI. Finally scattergrams of intubation time and RI were drawn against several factors. In univariate analyses, the MUF group had significantly shorter intubation time and better RI. Multivariate analysis revealed that the enforcement of MUF was an independent correlate of postoperative RI. Analyses on the scattergrams revealed that the above mentioned favorable effects of MUF were prominent in the patients younger than 3 years or weighing less than 10 kg. We concluded that MUF had significant effects on pulmonary function preservation in pediatric open heart operations, especially for smaller children.

Body Weight↗
PubMed2000

[An autopsy case of malignant lymphoma who showed hearing loss and cavernous sinus syndrome in the first stage and hemophagocytic syndrome].

A 48-year-old man was admitted to our hospital due to multiple cranial neuropathy such as vertigo, hearing loss of the left ear, visual loss of the left eye, left ptosis and total ophthalmoplegia of the left eye. Brain MRI revealed no abnormalities. After 10 days, he suddenly showed hemophagocytic syndrome with high fever, liver dysfunction, jaundice and pancytopenia. In spite of the treatment, he died of multiple organ failure after 26 days. At autopsy, malignant lymphoma cells of T cell origin directly invaded into the liver, spleen, intraperitoneal lymph nodes and other organs. Reports that direct invasion of lymphoma cells could be detected at the cranial nerves in the cavernous sinus are very rare.

Cavernous Sinus↗
PubMed2000

[Antithymocyte globulin treatment in 11 patients with aplastic anemia].

We report the response to, and toxicity of antithymocyte globulin (ATG) treatment in 11 consecutive patients (7 men and 4 women; median age 46 years) with aplastic anemia (AA). Six of the patients had severe disease and 5 had moderate disease; all were treated within one year from diagnosis. The ATG regimen was the initial treatment for 6 patients, but a sequential treatment for the other 5. Cyclosporin A was administered orally 1-3 weeks after the ATG treatment. All patients were assessed for over 6 months (median, 20.4 months); 8 showed a good response, 1 a minimal response, and 2 no response. Disease severity had no influence on the response. In 1 patient, ATG treatment had to be discontinued because of hepatic toxicity. However, adverse reactions were not severe in the other 10 patients. These findings suggest that ATG treatment is a safe and effective therapy for AA.

Adult↗
PubMed2000

[Three long surviving patients with gastric cancer metastasizing to the liver under interdisciplinary therapy].

In 30 patients with gastric cancer metastasizing to the liver over the past 15 years at our hospital the primary foci in the stomach could be resected in a curative manner. The authors report herein three long surviving patients in this series. [Case 1] A 49-year-old male. Distal gastrectomy was performed in November 1984. Metastasis to the liver occurred in June 1986. The right lobe of the liver was resected in November 1987 after transcatheter arterial embolization (TAE). Although hepatic arterial infusion chemotherapy was conducted, the cancer metastasized to the whole body, and the patient died in December 1991. [Case 2] A 65-year-old female. Distal gastrectomy was performed in July 1994. The left hepatic lobe and segment 5 in the right lobe were resected in June 1995. Although TAE was performed six times starting in December 1996, the patient died of hepatic failure in July 1999. [Case 3] A 73-year-old male. This patient simultaneously received distal gastrectomy and extended resection of the posterior hepatic segments in September 1997. Cancer recurred in the remaining liver in July 1998. Although microwave coagulation therapy (MCT) and TAE were performed, the patient died of hepatic failure in January 2000. In these patients who survived for a long period, the primary focus was well-differentiated adenocarcinoma under sufficient local control with metastasis limited to the nearest regional lymph nodes (group 1 lymph nodes). The patients could undergo interdisciplinary therapy, including hepatectomy, MCT, TAE, and hepatic arterial infusion chemotherapy.

Adenocarcinoma↗
PubMed2000

[A case of lateral origin of the left internal mammary artery].

A 66 years old men, with left anterior descending coronary artery (LAD) stenosis and aortic valve stenosis, underwent coronary artery bypass grafting (CABG) to LAD with left internal mammary artery (LIMA) and aortic valve replacement. His postoperative course was uneventful. But, postoperative angiogram showed that his patent LIMA graft was originated from much lateral side of the left subclavian artery. Internal mammary artery is considered the most ideal graft for CABG, but its' anomality is not well known. We present this rare case with the anomalous origin of LIMA.

Aged↗
PubMed1999

Alternative promoters direct tissue-specific expression of the mouse protein phosphatase 2Cbeta gene.

Type 2C protein phosphatases (PP2Cs), a class of ubiquitous and evolutionally conserved serine/threonine protein phosphatases, are encoded in at least four distinct genes and implicated in the regulation of various cellular functions. Of these four PP2C genes, the expression of the PP2Cbeta gene has been reported to be tissue-specific and development-dependent. To understand more precisely the regulatory mechanism of this expression, we have isolated and characterized overlapping mouse genomic lambda clones. A comparison of genomic sequences with PP2Cbeta cDNA sequences provided information on the structure and localization of intron/exon boundaries and indicated that PP2Cbeta isoforms with different 5' termini were generated by alternative splicing of its pre-mRNA. The 5'-flanking region of exon 1 had features characteristic of a housekeeping gene: it was GC-rich, lacked TATA boxes and CAAT boxes in the standard positions, and contained potential binding sites for the transcription factor SP1. In the 5'-flanking region of exon 2, several consensus sequences were found, such as a TATA-like sequence and negative regulatory element box-1, -2 and -3. Subsequent analysis by transient transfection assay with a reporter gene showed that these regions act as distinct promoters. Analysis of PP2Cbeta transcripts by reverse transcriptase-PCR showed that exon-1 transcripts were expressed ubiquitously in all of the tissues examined, whereas exon-2 transcripts were predominantly expressed in the testis, intestine and liver. These results suggest that the alternative usage of two promoters within the PP2Cbeta gene regulates tissue-specific expression of PP2Cbeta mRNA.

Animals↗
PubMed1999

Uptake and intracellular distribution of amrubicin, a novel 9-amino-anthracycline, and its active metabolite amrubicinol in P388 murine leukemia cells.

Amrubicin, a 9-aminoanthracycline anti-cancer drug, and its C-13 hydroxyl metabolite amrubicinol, were examined for growth-inhibitory activity as well as cellular uptake and distribution in P388 murine leukemia cells and doxorubicin-resistant P388 cells. Also discussed are the differences in the mechanisms of action among amrubicin, amrubicinol and doxorubicin in terms of their cellular pharmacokinetic character. In P388 cells, amrubicinol was about 80 times as potent as amrubicin, and about 2 times more potent than doxorubicin in a 1-h drug exposure growth-inhibition test. A clear cross-resistance was observed to both amrubicin and amrubicinol in doxorubicin-resistant P388 cells, though the resistance index was lower for amrubicin. The intracellular concentration of amrubicinol was about 6 times and 2 times higher than those of amrubicin and doxorubicin, respectively. Compared to doxorubicin, amrubicin and amrubicinol were released rapidly after removal of the drugs from the medium. A clear correlation was found between the growth-inhibiting activity and the cellular level of amrubicin and amrubicinol in P388 cells. About 10 to 20% of amrubicin or amrubicinol taken up by the cells was detected in the cell nuclear fraction, whereas 70 to 80% of doxorubicin was localized in this fraction. These results suggest that amrubicin and amrubicinol exert cytotoxic activity via a different mechanism from that of doxorubicin.

Animals↗