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Biomedical subjects

Y Koike

Publications and source records attributed to Y Koike.

At least 37 records · Page 2Linked to original sources
PubMed2001

A new reconstructive procedure after segmental pancreatectomy: an experimental study of pancreatic end-to-end (duct-to-duct) anastomosis.

We produced experimental models of pancreatic end-to-end anastomosis, including ductal end-to-end anastomosis (with or without stent) and pancreaticojejunostomy, using mongrel dogs, with a view to evaluating reconstructive procedures after segmental pancreatectomy. We examined macroscopic findings, pancreatograms, and microangiographic and histopathological findings to determine whether pancreatic end-to-end anastomosis was as practicable as pancreaticojejunostomy. Macroscopic findings showed no suture failure in any animal in the end-to-end anastomosis group. Pancreatography revealed obstruction of the stent tube in the stent subgroup, but good patency in the no-stent subgroup. On the imaging of the microvasculature in the end-to-end anastomosis group, proliferation of neovascular vessels and formation of communicating vessels were detected. Histopathologically, no suture failure was detected, and the viability of the pancreatic end-to-end anastomosis was confirmed. From this experiment, we concluded it that it was possible to employ pancreatic end-to-end anastomosis after segmental pancreatectomy in the clinical situation.

Anastomosis, Surgical↗
PubMed2001

Hepatocellular carcinoma depicted as hypoattenuation on CT hepatic arteriography (CTA) and hyperattenuation on CT during arterial portography (CTAP).

We report a 68-year-old man with three nodules of hepatocellular carcinoma (HCC) in a cirrhotic liver; the largest nodule was 3.0cm in diameter. The nodules showed hypoattenuation on computed tomography (CT) hepatic arteriography (CTA) and hyperattenuation on CT during arterial portography (CTAP), indicating that the dominant vascularity of the HCC nodules may have been the portal vein. A biopsy specimen obtained from the nodules showed well differentiated HCC (Edmondson-Steiner grade I). The imaging findings of the nodules on both CTA and CTAP are unusual, in spite of the rather large size, so this seemed suggestive of the hemodynamic properties of relatively large nodules of well differentiated HCC.

Aged↗
PubMed2001

Power Doppler signals after percutaneous ethanol injection therapy for hepatocellular carcinoma predict local recurrence of tumors: a prospective study using 199 consecutive patients.

BACKGROUND/AIMS: This study was prospectively conducted to elucidate the relationship between pre-/post-treatment power Doppler signals of hepatocellular carcinoma (HCC) and local recurrence. METHODS: One hundred ninety-nine consecutive patients with 359 HCC lesions receiving percutaneous ethanol injection therapy (PEIT) as a first-line option were enrolled. Arterial power Doppler signals in the tumor were found in 130 nodules, but not detected in 229. After confirmation of complete tumor necrosis on dynamic CT, Doppler signals in nodules were re-evaluated. Patients received periodical examinations to detect HCC recurrence. RESULTS: Local HCC recurrence was observed in 36 lesions; 22%(28/130) of the pretreatment signal positive lesions, in contrast to 3.5% (8/229) of the pretreatment signal negative lesions (P < 0.01). Out of 130 signal positive nodules, signals disappeared in 120 (92%) after PEIT, but were present in ten (8%). During the 25-month follow up, local recurrence was detected in 19 (16%) from the former, in contrast to nine (90%) from the latter (P < 0.001). Uni- and multivariate Cox analysis revealed that the presence of pre-/post-treatment power Doppler signals, histological differentiation and tumor number were independent factors for local recurrence. However, 3-year recurrence rate of new lesions was 51%, but no predictors were identified. CONCLUSIONS: Residual Doppler signals in tumor after PEIT were related to the local HCC recurrence.

Adult↗
PubMed2001

Percutaneous ethanol injection therapy for liver tumors.

Percutaneous ethanol injection therapy (PEIT) has been widely practiced in the treatment of liver tumors, especially of hepatocellular carcinoma (HCC). Histopathologic examinations, findings in imaging modalities and serum tumor marker levels have shown a remarkable anticancer effect of this procedure. In addition, PEIT has achieved considerably high long-term survival rates. For small HCC, PEIT has been generally accepted as an alternative to surgery. Here we will describe PEIT from the viewpoints of patient selection, technique, various evaluation procedures of efficacy, long-term results, side effects and complications, and relationship with other therapies.

Carcinoma, Hepatocellular↗
PubMed2001

Systematic characterization of human CD8+ T cells with natural killer cell markers in comparison with natural killer cells and normal CD8+ T cells.

We investigated the function of CD56+ CD8+ T cells (CD56+ T cells) and CD56- CD57+ CD8+ T cells (CD57+ T cells; natural killer (NK)-type T cells) and compared them with those of normal CD56- CD57- CD8+ T cells (CD8+ T cells) and CD56+ NK cells from healthy volunteers. After the stimulation with immobilized anti-CD3 antibodies, both NK-type T cells produced much larger amounts of interferon-gamma (IFN-gamma) than CD8+ T cells. Both NK-type T cells also acquired a more potent cytotoxicity against NK-sensitive K562 cells than CD8+ T cells while only CD56+ T cells showed a potent cytotoxicity against NK-resistant Raji cells. After the stimulation with a combination of interleukin (IL)-2, IL-12 and IL-15, the IFN-gamma amounts produced were NK cells > or = CD56+ T cells > or = CD57+ T cells > CD8+ T cells. The cytotoxicities against K562 cells were NK cells > CD56+ T cells > or = CD57+ T cells > CD8+ T cells while cytotoxicities against Raji cells were CD56+ T cells > CD57+ T cells > or = CD8+ T cells > or = NK cells. However, the CD3-stimulated proliferation of both NK-type T cells was smaller than that of CD8+ T cells partly because NK-type T cells were susceptible to apoptosis. In addition to NK cells, NK-type T cells but not CD8+ T cells stimulated with cytokines, expressed cytoplasmic perforin and granzyme B. Furthermore, CD3-stimulated IFN-gamma production from peripheral blood mononuclear cells (PBMC) correlated with the proportions of CD57+ T cells in PBMC from donors. Our findings suggest that NK-type T cells play an important role in the T helper 1 responses and the immunological changes associated with ageing.

Adult↗
PubMed2001

Spinal leptomeningeal metastases of giant cell glioblastoma associated with subarachnoid haemorrhage: case report.

A case of subarachnoid haemorrhage (SAH) due to spinal leptomeningeal metastases of a giant cell glioblastoma is described. A 51 year old male presented with a four week history of headache. Neurological examination was normal except for a slight left hemiparesis. Computed tomography (CT) revealed a large cyst with a mural nodule in the right temporal lobe. The tumour was removed followed by 60 Gy of radiation therapy. Thirty-two months later he developed headache and shoulder pain with symptoms of normal pressure hydrocephalus. Head CT showed ventriculomegaly and SAH. Magnetic resonance imaging showed spinal leptomeningeal metastases at the C4-5, T12, and L2 levels, but no local recurrence or tumour dissemination in the brain. He died 34 months after surgery. Autopsy revealed diffuse SAH over the whole brain and spinal cord, associated with spinal leptomeningeal metastases, but no cerebral aneurysms. Spinal radiotherapy and ventriculoperitoneal shunting could possibly have extended survival in this patient.

Brain Neoplasms↗
PubMed2001

Effect of consumed carbon to nitrogen ratio of mycelial morphology and arachidonic acid production in cultures of Mortierella alpina.

The influence of the consumed carbon to nitrogen (C/N) ratio on arachidonic acid (AA) production and mycelial morphology was investigated in cultures of Mortierella alpina using shake flasks and a fermentor. The consumed C/N ratio was varied from 5 to 32 under the condition that the total initial amount of carbon and nitrogen sources was 50 g/l. Cellular yield increased markedly at C/N ratios below 7; carbon utilization was switched from cellular growth to lipid biosynthesis in the C/N ratio range of 7-15; lipid biosynthesis was most active when the C/N ratio was in the range of 15-32. However, for C/N ratios higher than 15, the mycelial concentration decreased due to nitrogen limitation but the lipid yield still increased. In the presence of excess nitrogen, the biomass concentration depended on the amount of the nitrogen source, but the AA yield was inversely related to this. On the other hand, in the presence of excess carbon, the fatty acid concentration increased with carbon source concentration but the AA concentration remained constant. From the viewpoint of AA production, the optimum C/N ratio was in the range of 15 to 20 with a balance between the amounts of carbon and nitrogen sources. When an enriched medium was used at a fixed C/N ratio of 20, the cellular and AA concentrations were shown to be proportional to the total concentrations of carbon and nitrogen sources in both flasks and the fermentor. The whole pellet size and width of pellet annular regions did not change with increasing C/N ratio for C/N ratios below 20 in the flask cultures. However, when the C/N ratio was higher than 20, these sizes increased in proportion to the C/N ratio.

Journal Article↗
PubMed2001

Clinical efficacy of fidarestat, a novel aldose reductase inhibitor, for diabetic peripheral neuropathy: a 52-week multicenter placebo-controlled double-blind parallel group study.

OBJECTIVE: The purpose of this study was to evaluate the efficacy of fidarestat, a novel aldose reductase (AR) inhibitor, in a double-blind placebo controlled study in patients with type 1 and type 2 diabetes and associated peripheral neuropathy. RESEARCH DESIGN AND METHODS: A total of 279 patients with diabetic neuropathy were treated with placebo or fidarestat at a daily dose of 1 mg for 52 weeks. The efficacy evaluation was based on change in electrophysiological measurements of median and tibial motor nerve conduction velocity, F-wave minimum latency, F-wave conduction velocity (FCV), and median sensory nerve conduction velocity (forearm and distal), as well as an assessment of subjective symptoms. RESULTS: Over the course of the study, five of the eight electrophysiological measures assessed showed significant improvement from baseline in the fidarestat-treated group, whereas no measure showed significant deterioration. In contrast, in the placebo group, no electrophysiological measure was improved, and one measure significantly deteriorated (i.e., median nerve FCV). At the study conclusion, the fidarestat-treated group was significantly improved compared with the placebo group in two electrophysiological measures (i.e., median nerve FCV and minimal latency). Subjective symptoms (including numbness, spontaneous pain, sensation of rigidity, paresthesia in the sole upon walking, heaviness in the foot, and hypesthesia) benefited from fidarestat treatment, and all were significantly improved in the treated versus placebo group at the study conclusion. At the dose used, fidarestat was well tolerated, with an adverse event profile that did not significantly differ from that seen in the placebo group. CONCLUSIONS: The effects of fidarestat-treatment on nerve conduction and the subjective symptoms of diabetic neuropathy provide evidence that this treatment alters the progression of diabetic neuropathy.

Aldehyde Reductase↗
PubMed2000

A covariant change of the two highly conserved bases in the GTPase-associated center of 28 S rRNA in silkworms and other moths.

The GTPase-associated center in 23/28 S rRNA is one of the most conserved functional domains throughout all organisms. We detected a unique sequence of this domain in Bombyx mori species in which the bases at positions 1094 and 1098 (numbering from Escherichia coli 23 S rRNA) are C and G instead of the otherwise universally conserved bases U and A, respectively. These changes were also observed in four other species of moths, but not in organisms other than the moths. Characteristics of the B. mori rRNA domain were investigated by native polyacrylamide gel electrophoresis using RNA fragments containing residues 1030-1128. Although two bands of protein-free RNA appeared on gel, they shifted to a single band when bound to Bombyx ribosomal proteins Bm-L12 and Bm-P complex, equivalent to E. coli L11 and L8, respectively. Bombyx RNA showed lower binding capacity than rat RNA for the ribosomal proteins and anti-28 S autoantibody, specific for a folded structure of the eukaryotic GTPase-associated domain. When the C(1094)/G(1098) bases in Bombyx RNA were replaced by the conserved U/A bases, the protein-free RNA migrated as a single band, and the complex formation with Bm-L12, Bm-P complex, and anti-28 S autoantibody was comparable to that of rat RNA. The results suggest that the GTPase-associated domain of moth-type insects has a labile structural feature that is caused by an unusual covariant change of the U(1094)/A(1098) bases to C/G.

Animals↗
PubMed2000

Hemin pretreatment ameliorates aspects of the nephropathy induced by mercuric chloride in the rat.

Mercuric chloride (HgCl(2)) is known to be a nephrotoxicant. When HgCl(2) is administered into rats, acute renal failure (ARF) is induced. Heme oxygenase-1 (HO-1) is antioxidative enzyme and is known to play a protective role against the oxidative injury. To elucidate the cytoprotective role of HO-1 against the nephrotoxicant-induced ARF, we examined the effect of hemin, HO-1 inducer, on HgCl(2)-induced ARF. Subcutaneous administration of hemin (30 mg/kg body weight) into rats once a day for two successive days obviously induced HO-1 protein in the kidneys at 24 h after the last injection. Under this situation, when HgCl(2) (1 mg/kg body weight) was intraperitoneally injected into rats at 24 h after the last injection of hemin improved the serum creatinine (SCr) and blood urea nitrogen (BUN) levels, markers for renal injury, at 24 h after the HgCl(2) injection as compared with the control rats without hemin pretreatment (HgCl(2) treatment alone). This result was further confirmed by histopathological analysis. These findings strongly suggest that the preinduction of HO-1 ameliorates the subsequent HgCl(2)-induced acute renal injury.

Acute Kidney Injury↗
PubMed2000

Heterologous expression of clostridial hydrogenase in the Cyanobacterium synechococcus PCC7942.

The Clostridium pasteurianum hydrogenase I has been expressed in the cyanobacterium Synechococcus PCC7942. The Shine-Dalgarno sequence of the structural gene encoding hydrogenase I from C. pasteurianum was changed to that of the cat (chloramphenicol acetyltransferase) gene. The hydrogenase gene was cloned downstream of a strong promoter, isolated from Synechococcus PCC7942, with the cat gene as a reporter gene. Expression of clostridial hydrogenase was confirmed by Western and Northern blot analyses in Synechococcus and Escherichia coli, whereas in vivo/in vitro measurements and activity staining of soluble proteins separated on non-denaturing polyacrylamide gels revealed functional expression of hydrogenase only in cyanobacterial cells. The changed Shine-Dalgarno sequence appeared to be essential for the functional expression of clostridial hydrogenase in Synechococcus, but had no influence on the expression and activity of clostridial hydrogenase expressed in E. coli.

Blotting, Northern↗
PubMed2000

Brainstem-type Lewy body disease presenting with progressive autonomic failure and lethargy.

The authors report an autopsy case characterized by progressive lethargy and autonomic failure with a distinctive pattern of occurrence of Lewy bodies. Autonomic dysfunction such as sleep apnea, orthostatic hypotension, dysuria, and hypohidrosis predominated with lethargy, whereas parkinsonism was not apparent. Numerous Lewy bodies were widely evident microscopically in brainstem nuclei and the intermediolateral cell columns of the spinal cord, as well as in the sympathetic ganglia, but were rare or absent in the cerebral cortex and other supratentorial structures. Marked neuronal loss was seen in the locus ceruleus, raphe nuclei, dorsal vagal nuclei, and intermediolateral cell columns, but neurons in the substantia nigra, other brain regions, and sympathetic ganglia appeared undiminished. This case represents a specific clinicopathologic form of Lewy body disease occurring predominantly in the brainstem, spinal cord, and sympathetic ganglia.

Autonomic Nervous System↗
PubMed2000

Holding characteristics of planar objects suspended by near-field acoustic levitation

The authors have found the acoustic levitation phenomenon where planar objects of 10 kg weight can be levitated near a vibration surface. This phenomenon has been studied for non-contact transportation. A circular planar object can be suspended without contacting a circular vibration plate. We have studied the holding force which acts horizontally on the levitated objects. The horizontal position of the object is stabilized by this force. In this paper, we discuss the effect of the radius of a levitated object, levitation distance, displacement amplitude of the vibration plate and the vibration mode on the suspending force.

Journal Article↗
PubMed2000

Non-contact transportation using near-field acoustic levitation

Near-field acoustic levitation, where planar objects 10 kg in weight can levitate stably near the vibrating plate, is successfully applied both to non-contact transportation of objects and to a non-contact ultrasonic motor. Transporting apparatuses and an ultrasonic motor have been fabricated and their characteristics measured. The theory of near-field acoustic levitation both for a piston-like sound source and a flexural vibration source is also briefly described.

Journal Article↗