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Biomedical subjects

Y Wakabayashi

Publications and source records attributed to Y Wakabayashi.

At least 73 records · Page 4Linked to original sources
PubMed1998

Third ventricular neuroepithelial cyst originating from the massa intermedia--case report.

A 47-year-old female presented with a 3-year history of progressive emotional disturbance. Computed tomography and magnetic resonance imaging revealed a cyst in the third ventricle causing hydrocephalus. Endoscopic surgery found the cyst originated at the massa intermedia. Histological examination confirmed the diagnosis of neuroepithelial cyst. Neuroepithelial cyst originating from the massa intermedia may be due to persistence of neuroepithelial crest at this location.

Cerebral Ventricles↗
PubMed1998

[Intracranial mesenchymal chondrosarcoma arising from the cerebellar tentorium: case report].

A 22-year-old woman presented with a 3-year history of progressive frontal headache. Computerized tomography (CT) and magnetic resonance imaging (MRI) revealed a tumor in the left trigone of the lateral ventricle and which enhanced homogeneously. The tumor was attached to the cerebellar tentorium and was compressing the brain stem. On the angiography, no tumor staining was seen. On November 26, 1996, total removal of the tumor was performed using the left subtemporal approach. The tumor was attached to the cerebellar tentorium. The pathological diagnosis was mesenchymal chondrosarcoma. After surgery, gamma-knife radiosurgery was carried out on the tentorium at the place where the tumor had been attached. There has been no recurrence for 6 months. Mesenchymal chondrosarcoma in the brain is very rare and therapy for this tumor is difficult. We report this rare tumor and the therapy is discussed.

Adult↗
PubMed1998

[Placing two parallel catheters by Seldinger's approach through the femoral artery for CT angiography and CT during arterioportography: evaluation of efficacy and safety].

The purpose of this study was to evaluate the efficacy and safety of placing two parallel catheters by Seldinger's approach through the femoral artery for CT angiography (CTA) and CT during arterioportography (CTAP). We performed an analysis of 30 patients. Two introducers were successfully placed in all cases. Only one minor complication was observed, a localized inguinal hematoma. The CTA/CTAP procedures were successful in all patients except six who had anatomical variations of the hepatic arterial supply. Our methods proved to be useful and safe for patients with standard hepatic arterial supply.

Angiography↗
PubMed1998

[A case of juvenile rheumatoid arthritis with MPO-ANCA associated nephritis].

A 12-year-old girl with a main complaint of sever pain on the both knees was admitted to our hospital in October, 1995. She gave a three year history of recurrent arthralgia and purpuric rashes, and persistent microhematuria and proteinuria. She developed vesicles and purpuric rashes on the hands and auricles, morning stiffness, fever, uveitis and pericarditis. Laboratory findings showed an elevated level of erythrocyte sedimentation rate and iron-deficiency anemia. Serum perinuclear pattern ANCA with antimyeloperioxidase specificity (MPO-ANCA) was positive. A renal biopsy specimen disclosed a focal and segmental necrotizing glomerulonephritis with crescents. Our case fulfills the both diagnostic criteria for polyarteritis nodosa and juvenile rheumatoid arthritis. This is a rare case of MPO-ANCA associated vasculitis in children.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1998

[Three-dimensional CT angiography for cerebral aneurysm using a multi-angle reconstruction plan method].

The purpose of this study was to evaluate the clinical usefulness of three-dimensional CT angiography (3D-CTA) for the diagnosis of cerebral aneurysm using a new reconstruction method called Multi-Angle Reconstruction Plan (MARP). The threshold values, region of interest and six angles of view were preset for the MARP method on the basis of our experience with cerebral 3D-CTA. Spiral CT angiography was performed in 27 patients with 29 aneurysms. The six images reconstructed with the MARP method were generated from the volumetric CT data. Two radiologists independently reviewed the six 3D-CT images for the presence of aneurysm. It took about five minutes to semiautomatically reconstruct the six 3D-CT images with the MARP method. There were no discrepancies in the evaluation of the 3D-CT images. Twenty-six aneurysms of 24 patients were demonstrated on the six 3D-CT images. Three aneurysms in 3 patients were not depicted on the 3D-CT images by the MARP method. In them, the additional 3D-CT images which were generated after evaluating the 2D-CT images clearly showed the aneurysms. The MARP method is considered to be a useful three-dimensional reconstruction technique for the diagnosis of cerebral aneurysm.

Adult↗
PubMed1998

Increase of low-affinity neurotrophin receptor p75 and growth-associated protein-43 immunoreactivities in the rat urinary bladder during experimentally induced nerve regeneration.

PURPOSE: Nerve regeneration in the urinary bladder after pelvic nerve plexus injury remains uncertain. The objectives were to establish a rat model of nerve regeneration in the bladder and to examine possible changes of low-affinity neurotrophin receptor p75 and growth-associated protein-43 (GAP-43) immunoreactivities during denervation and nerve regeneration. MATERIALS AND METHODS: Adult male rats were divided into 3 groups: controls, crush of the nerve bundles from the right major pelvic ganglion (MPG) to the bladder (nerve crush group) and removal of the right MPG (MPG removal group). Bladders were collected at 3, 7, 14, 30 and 60 days, and immunohistochemically stained for protein gene product 9.5 (PGP9.5: an axonal marker), p75 and GAP-43. RESULTS: In the nerve crush group, PGP9.5 positive nerves were decreased in number at 3 and 7 days, and then increased after 14 days in the muscle layer of the operated side. By 60 days, the density returned to control levels. However, MPG removal resulted in a decrease of the density of PGP9.5 positive nerves throughout the experimental periods. These findings indicate that nerve regeneration occurred in the nerve crush group. The density of p75 labeled fibers was significantly increased at 3 to 30 days postoperatively in the nerve crush group. p75 immunoreactivity showed smooth surface and cytoplasmic staining, indicating that Schwann cells were p75 positive. GAP-43 labeled fibers showed significantly greater density at 3 to 14 days postoperatively. Schwann cells were GAP-43 immunoreactive and, in particular, regenerating nerve fibers appeared to be GAP-43 positive at 14 days. CONCLUSION: The present study suggests that p75 and GAP-43 are involved in the mechanism(s) of nerve regeneration in the urinary bladder.

Animals↗
PubMed1998

[Usefulness of 123I-MIBG scintigraphy for prediction of effect of beta-blocker therapy in dilated cardiomyopathy].

To determine whether 123I-MIBG (MIBG) scintigraphy is useful for predicting the effect of beta-blocker therapy in patients with dilated cardiomyopathy (DCM), we studied MIBG scintigraphy in 11 controls and 9 patients with DCM before starting beta-blocker therapy. First, initial and delayed heart-to-mediastinum ratios (H/M ratio) of MIBG activity in patients with DCM were significantly lower than those in 11 controls, respectively (initial H/M; 1.8 +/- 0.3 vs. 2.1 +/- 0.3, p < 0.02, delayed H/M; 1.6 +/- 0.3 vs. 2.4 +/- 0.2, p < 0.0001), and MIBG washout rate from the heart was significantly higher in patients than in controls (washout rate; 33 +/- 7% vs. 22 +/- 4%, p < 0.0005). Second, beta-blocker therapy improved LVEF in 7 patients (improved group), while it resulted in deterioration of heart failure, followed by death in 2 patients (deteriorated group). Although initial and delayed H/M ratios in the improved group were not significantly different from those in the deteriorated group, respectively, MIBG washout rate was significantly higher in the deteriorated group than in the improved group (45 +/- 8% vs. 30 +/- 3%, p = 0.04). Our study suggests that DCM patients with markedly rapid MIBG clearance may be deteriorated by beta-blocker therapy. In contrast, there were no differences in LVEF and plasma norepinephrine between improved and deteriorated groups. In conclusion, 123I-MIBG scintigraphy is useful for predicting the effects of beta-blocker therapy in patients with DCM.

3-Iodobenzylguanidine↗
PubMed1998

[PNP deficiency].

Explore the source record for details and available documents.

Deoxyguanine Nucleotides↗
PubMed1997

Genetic and physical delineation of the region of the mouse deafness mutation shaker-2.

A total of 951 backcross progeny have been obtained from a backcross segregating for the mouse deafness mutation, shaker-2(sh-2). Linkage analysis provides a detailed genetic map in the vicinity of sh-2 which comprises 40 backcross mice identified as recombinant within a 4 cM region. This allows construction of a contig consisting of 21 BAC clones across an approximately 700-kb region of sh-2. This covers the entire nonrecombinant region of sh-2 and is therefore useful to facilitate the identification of genes in the sh-2 region.

Animals↗
PubMed1997

Immunohistochemical localization of low-affinity nerve growth factor receptor in the enteric nervous system of adult rats.

The localization of low-affinity nerve growth factor receptor in the enteric nervous system of adult rats has been studied by immunohistochemistry using a monoclonal antibody (clone 192) against the rat receptor. Cryostat and whole-mount sections were stained. By light and confocal microscopy, positive staining in neural structures was found in every part of the gut. In the ganglionic plexus, dense staining was detected in the neuropil surrounding neuronal cell bodies that were themselves devoid of immunoreactivity. Immunoelectron microscopy revealed deposition of reaction products on the outer plasma membranes of both perikarya and processes of neuronal as well as glial cells. Such a selective localization of the receptor in the plasma membrane, but not the cytoplasm, suggests that the mechanisms of receptor-ligand interaction in the gut may differ from those in the brain, where internalization of the receptor is observed in cholinergic cells. The present study provides the morphological basis for future studies designed to elucidate the functional significance of this enteric nervous system receptor. Since it is found in both neuronal and glial cells, it is probably under the influence of a number of trophic factors, including nerve growth factor.

Animals↗
PubMed1997

Leukocyte-endothelium interaction in the rat mesenteric microcirculation during halothane or sevoflurane anesthesia .

BACKGROUND: The effects of inhalational anesthetics on the microcirculation, including leukocyte dynamics, remain to be clarified. The authors investigated halothane and sevoflurane anesthesia to determine if these agents evoked leukocyte adhesion through endothelial cell-dependent mechanisms involving such adhesion molecules. METHODS: Rats were anesthetized with halothane or sevoflurane in 100% oxygen and the lungs were mechanically ventilated. Leukocyte behavior in mesenteric venules was recorded through intravital video microscopy under monitoring microvascular hemodynamics. To examine the mechanisms for leukocyte rolling and adhesion, these studies were repeated after animals were pretreated with a monoclonal antibody against P-selectin (MAb PB1.3) or against intracellular adhesion molecule-1 (ICAM-1; MAb 1A29): P-selectin required for rolling of circulating leukocytes and ICAM-1 for firm adhesive interactions with leukocyte integrins. RESULTS: Under baseline anesthetic conditions (1 minimum alveolar concentration [MAC]), venular wall shear rates, an index of the disperse force on marginating leukocytes, in the sevoflurane-treated rats were about two times higher than those with halothane. At 2 MAC, halothane caused a marked arteriolar constriction and decreasing shear rates concurrent with an increasing density of venular leukocyte adhesion. Sevoflurane at 2 MAC induced leukocyte rolling and adhesion, which were attenuated by PB1.3 and 1A29, without alterations in the wall shear rates. Halothane-induced leukocyte adhesion was not prevented by PB1.3 but it was by 1A29. CONCLUSIONS: Halothane or sevoflurane anesthesia induces venular leukocyte rolling and adhesion: P-selectin upregulation plays a crucial role in leukocyte rolling and adhesion during sevoflurane anesthesia, whereas low-flow perfusion is likely to evoke ICAM-1-dependent leukocyte adhesion during halothane anesthesia.

Anesthetics, Inhalation↗
PubMed1997

Telomerase activity and metastasis: expansion of cells having higher telomerase activity within culture lines and tumor tissues.

Tumor cells with metastatic potential may have a high telomerase activity that augments telomeric DNA repeats, allowing the cells to escape from the inhibition of cell proliferation due to shortened telomeres. We examined the expression level of telomerase activity using the telomeric repeat amplification protocol among a series of cell lines obtained by repeated transplantation of a mouse fibrosarcoma. The lines could be grouped into three; one has no metastatic potential, and the other two show metastatic abilities after intravenous or subcutaneous injection. Comparison of their telomerase activity indicated that more malignant lines had higher activity. A similar relation was seen in metastatic nodules formed through clonal expansion from the heterogeneous population of inoculated cells; clonality was monitored in terms of variable patterns of subtelomeric repeats. The results suggest that a high level of telomerase activity may not be requisite for metastasis, but may confer a propensity to dominate in a tumor tissue.

Animals↗
PubMed1997

Electrophysiological characterization of cultured hepatic stellate cells in rats.

This study aimed to examine electrophysiological properties of cultured rat hepatic stellate cells (HSCs) using the whole cell configuration of patch-clamp technique. At least three different current components were identified. First, when the membrane was depolarized to voltages more positive than -40 mV, a transient outward K+ current was evoked. Second, membrane hyperpolarization below -60 mV evoked a sustained and inward-rectifying K+ current. The third component was a current flowing outward, which was activated when the cell was depolarized more positively than 0 mV. The channel for this current allowed Na+, K+, and Cl- to pass nonspecifically, suggesting the presence of hemi gap-junctional channel. Furthermore, a laser photobleaching technique revealed the presence of gap junctions between adjacent HSCs. A voltage-gated Ca2+ current, which is known to occur in smooth muscle cells, was searched for but was not detectable. These results suggest that membrane potential of HSCs is determined specifically by the two distinct K+ channels and by an intercellular mechanism involving gap-junctional communication.

Animals↗