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Biomedical subjects

R Nishimura

Publications and source records attributed to R Nishimura.

At least 181 records · Page 10Linked to original sources
PubMed1994

Computed tomography on renal masses in dogs and cats.

Computed tomography (CT) was performed on renal tumors (Wilms' tumor and renal cell carcinoma) and renal cysts in dogs and cats. CT images in renal tumors were well correlated with macroscopic findings, and contrast CT images were quite useful in differentiating tumoral regions from non-tumoral ones. On renal cysts, intravenous pyelography and ultrasonography were as effective as CT images in morphological diagnosis, but CT was considered to be superior for evaluating three-dimensional (3-D) relationships in complicated lesions.

Animals↗
PubMed1994

Comparison of sedative effects induced by medetomidine, medetomidine-midazolam and medetomidine-butorphanol in dogs.

Sedative effects of combinations of medetomidine at 20 micrograms/kg--midazolam at 0.3 mg/kg (Me-Mi) and medetomidine at 20 micrograms/kg--butorphanol at 0.1 mg/kg (Me-B) were evaluated comparing with those of medetomidine alone (20, 40 and 80 mu/kg). All dogs given Me-Mi or Me-B were smoothly and rapidly induced to more profound and longer sedation than those by medetomidine alone. Especially, Me-Mi produced desirable sedation with moderate reflex depression, analgesia, excellent muscle relaxation and immobilization without further side effects. This potent effect of this combination seemed to be induced by a synergistic interaction between medetomidine and midazolam. This combination is available and valuable as a chemical restraint agent in dogs for various diagnostic or therapeutic procedures accompanied by light pain.

Animals↗
PubMed1993

Nck associates with the SH2 domain-docking protein IRS-1 in insulin-stimulated cells.

Nck, an oncogenic protein composed of one SH2 and three SH3 domains, is a common target for various cell surface receptors. Nck is thought to function as an adaptor protein to couple cell surface receptors to downstream effector molecules that regulate cellular responses induced by receptor activation. In this report, we show that Nck forms a stable complex in vivo with IRS-1 in insulin-stimulated cells. The interaction between IRS-1 and Nck is mediated by the binding of the SH2 domain of Nck to tyrosine-phosphorylated IRS-1. Although Nck associates with IRS-1, Nck phosphorylation is not affected by insulin stimulation. Furthermore, in vitro and in vivo studies show that the SH2 domains of Nck, GRB2, and p85 bind distinct phosphotyrosine residues in IRS-1. After insulin stimulation all three signaling molecules can be found complexed to a single IRS-1 molecule. These findings provide further evidence that, in response to insulin stimulation, IRS-1 acts as an SH2 docking protein that coordinates the regulation of various different signaling pathways activated by the insulin receptor.

Adaptor Proteins, Signal Transducing↗
PubMed1993

Charge isomers of urinary bikunin (trypsin inhibitor).

It was observed that the purified urinary bikunin (trypsin inhibitor) consisted of four major isomers with different electric charges which could be separated by HPLC using a Mono Q column. These isomers revealed the same antitrypsin activity and did not show any differences in the apparent molecular weight by SDS-PAGE, amino-acid composition, N-terminal amino-acid sequence (1-40) and C-terminal amino acid (Leu). The contents of sialic acid and uronic acid were also identical among these isomers. However, analysis of chondroitin sulfate revealed all the glycosaminoglycan chains of these isomers were undersulfated, comprising nonsulfated and 4-sulfated disaccharide units, and 4-sulfated disaccharide unit ratio varied among these isomers. After the chondroitin ABC lyase digestion, all the isomers were eluted at the same position on a Mono Q column chromatography. These results indicated that charge isomers of urinary bikunin was attributed to the difference on sulfation ratio in a glycosaminoglycan chain.

Amino Acids↗
PubMed1993

Liquid chromatography-mass spectrometry for the determination of medetomidine and other anaesthetics in plasma.

A liquid chromatographic-atmospheric pressure chemical ionization mass spectrometric method is presented for the simultaneous determination of medetomidine and other anaesthetic drugs in solutions and dog plasma. The drugs examined were flumazenil, butorphanol, atropine, ketamine, xylazine, medetomidine, atipamezole and midazolam. The separation was carried out on a reversed-phase column using methanol-0.1 M ammonium acetate (3:2) as eluent.

Anesthetics↗
PubMed1993

Thoracic vertebral bone metastasis from uterine leiomyosarcoma.

We report a patient with solitary thoracic vertebral bone metastasis (Th 8) from uterine leiomyosarcoma. The vertebral metastatic lesion was treated surgically, and vertebral body replacement with ceramic prosthesis and anterior spinal stabilization were performed. Such aggressive surgical intervention for solitary vertebral bone metastasis may contribute to the improvement of prognosis and maintenance of general quality of life in the patient.

Female↗
PubMed1993

Correlation of sequential magnetic resonance imaging of experimental brain ischemia with histologic changes in gerbils.

RATIONAL AND OBJECTIVES: To characterize Gd-DTPA-enhanced T1-weighted images (Gd-T1WI) in the acute phase of cerebral ischemia, sequential magnetic resonance images of 84 Mongolian gerbils with occlusion of the left common carotid artery were evaluated. METHODS: Twelve gerbils were used for each group, among which the occlusion time (5-180 minutes, permanent) varied. Histopathologic changes developing within the first 2 weeks were compared with patterns on T2-weighted images and Gd-T1WI on a 7.05-Tesla system. RESULTS: Although T2-weighted images and Gd-T1WI both demonstrated abnormal findings as early as 3 hours after occlusion, Gd-T1WI demonstrated more definite abnormalities with shorter occlusion than T2-weighted images (especially when there were only mild histologic changes). The earliest changes were an abnormal enhancement around and within the lateral ventricles in temporary occlusions; this was not demonstrated in permanent occlusions. CONCLUSIONS: Magnetic resonance images using Gd-DTPA demonstrated abnormal permeability within 3 hours after occlusion, and the pattern is correlated with intensity of ischemia.

Animals↗
PubMed1993

Establishment of a leukaemic cell line from a patient with acquisition of chromosomal abnormalities during disease progression in myelodysplastic syndrome.

A cell line designated SKM-1 was newly established from leukaemic cells of a 76-year-old Japanese male patient with monoblastic leukaemia following myelodysplastic syndrome (MDS). The cells were obtained from peripheral blood of the patient when he lost multiple point mutations of ras genes with acquisition of chromosomal abnormalities during disease progression in MDS. The cells grew as a single floating cell, and have been continuously growing with the morphological characteristics of immature monoblasts by serial passages during the past 42 months with a doubling time of about 48 h. By cytochemical analysis, the cloned cells were positive for butyrate esterase, but negative for the Epstein-Barr virus associated nuclear antigen. Phenotypic analysis revealed the expression of myelomonocyte specific antigens such as CD4, CD13, CD33 and HLA-DR. Cells from the primary peripheral blood and those from 50 passages of the SKM-1 cell line both possessed no activated ras genes but showed karyotype abnormalities with 46,XY, del(9)(q13;q22), der(17) t(17;?)(p13;?). The SKM-1 cells have two mutations in p53 gene and overexpress the p53 products. This cell line may contribute to a better understanding of molecular mechanisms in the progression from MDS to myelogenous leukaemia.

Aged↗
PubMed1993

Two signaling molecules share a phosphotyrosine-containing binding site in the platelet-derived growth factor receptor.

Autophosphorylation sites of growth factor receptors with tyrosine kinase activity function as specific binding sites for Src homology 2 (SH2) domains of signaling molecules. This interaction appears to be a crucial step in a mechanism by which receptor tyrosine kinases relay signals to downstream signaling pathways. Nck is a widely expressed protein consisting exclusively of SH2 and SH3 domains, the overexpression of which causes cell transformation. It has been shown that various growth factors stimulate the phosphorylation of Nck and its association with autophosphorylated growth factor receptors. A panel of platelet-derived growth factor (PDGF) receptor mutations at tyrosine residues has been used to identify the Nck binding site. Here we show that mutation at Tyr-751 of the PDGF beta-receptor eliminates Nck binding both in vitro and in living cells. Moreover, the Y751F PDGF receptor mutant failed to mediate PDGF-stimulated phosphorylation of Nck in intact cells. A phosphorylated Tyr-751 is also required for binding of phosphatidylinositol-3 kinase to the PDGF receptor. Hence, the SH2 domains of p85 and Nck share a binding site in the PDGF receptor. Competition experiments with different phosphopeptides derived from the PDGF receptor suggest that binding of Nck and p85 is influenced by different residues around Tyr-751. Thus, a single tyrosine autophosphorylation site is able to link the PDGF receptor to two distinct SH2 domain-containing signaling molecules.

Amino Acid Sequence↗
PubMed1993

Isolation and identification of canine plasma components suspected as uremic toxins.

Suspected uremic substances contained in four fractions, which had been selected as the suspected canine uremic peaks in the previous study, were isolated by two stages of preparative liquid chromatography (PLC) from plasma of uremic dogs treated with the ligation of the ureter, and then their physicochemical properties were examined. The primary separation of the suspected uremic peaks were performed with the same anion exchange resin as used in the analytical HPLC in the previous study. Analytical reverse phase HPLC showed that three of 4 suspected uremic peaks almost consisted of single substances, but the other contained several substances. Main subfractions of these peaks were successfully isolated by the secondary stage reverse phase PLC. By means of thin layer chromatography, ultraviolet absorption spectrometry and proton-nuclear magnetic resonance spectroscopy, components of 4 main peaks were confirmed to be small molecules such as a pyridine derivative, uric acid, hippuric acid and kynurenic acid, respectively.

Animals↗
PubMed1993

Cardiopulmonary effects of a combination of medetomidine and butorphanol in atropinized pigs.

Cardiopulmonary effects of a combination of medetomidine and butorphanol were evaluated in atropinized pigs. This combination unchanged the cardiac output and significantly lowered the oxygen consumption compared with base-line values. Although some statistically significant changes were recorded, both medetomidine and butorphanol did not have a marked effect on the cardiopulmonary parameters in atropinized pigs. It was indicated that the administration of the combination of medetomidine and butorphanol is relatively safe in atropinized pigs.

Adrenergic alpha-Agonists↗
PubMed1993

Collagen production and maturation at the experimental ligament defect stimulated by pulsing electromagnetic fields in rabbits.

Eighty rabbits receiving the square resection (4 x 4 mm) of both patellar ligaments in full thickness at their center were divided into 4 groups, and each group (20 rabbits) were electromagnetically stimulated with different magnetic intensities, 0 (control group), 2, 10, or 50 gauss (G), for 6 hr daily. Pulse frequency and pulse width were 10 Hz and 25 microseconds, respectively. Five animals of each group were sacrificed weekly from 1st to 4th week after operation and the defect tissue was collected for biochemical and ultrastructural evaluations. Before sacrificing, the blood flow of the central portion of patellar defects were measured. Significant increases in blood flow at the defect were observed in 50 G group compared to those of other groups from 2 to 4 weeks after operation. The collagen content in PEMFs groups showed a significant increase compared to that of control group. Furthermore, those increases were higher according to the increase in magnetic intensity. Electronmicroscopically, massive developmental rough endoplasmic reticulum was seen in the fibroblasts at 2 weeks after operation in 50 G group compared to other groups, which suggests the more active collagen production in this group. These results suggest that PEMFs enhanced the blood flow and increased the fibroblasts at the defect. At the same time, PEMFs directly stimulated the collagen production from the fibroblasts, thus accelerate the healing process of the ligament.

Animals↗
PubMed1993

Comparison of sedative and analgesic/anesthetic effects induced by medetomidine, acepromazine, azaperone, droperidol and midazolam in laboratory pigs.

The sedative and analgesic/anesthetic effects of medetomidine, acepromazine, azaperone, droperidol and midazolam were compared in laboratory pigs. In these sedatives, medetomidine produced the most profound degree of sedation with greater drowsiness than was achieved by other sedatives tested. Medetomidine induced sedation accompanied with weak analgesia and muscle relaxation smoothly and quickly and depressed arousal reaction deeply as compared with other sedatives. Pigs given medetomidine were not aroused easily even by moderately rough stimulation for approximately 60 min after injection.

Acepromazine↗
PubMed1993

Sedative effect induced by a combination of medetomidine and midazolam in pigs.

Sedative and analgesic/anesthetic effects induced by a combination of medetomidine and midazolam were evaluated in pigs. This combination exerted a much more potent sedative effect than that induced by a medetomidine alone, even if the dose of medetomidine was reduced to one half, and even if the pigs were stimulated continuously during the induction phase. Pigs given this combination were induced to sedation smoothly and very quickly. During being sedated the arousal reaction induced by sensory stimuli were depressed profoundly and pigs could be placed in dorsal recumbency without any resistance. In addition, this combination produced moderate analgesic effect and apparent muscle relaxation. This potent effect induced by this combination seemed to be induced by a synergistic interaction between medetomidine and midazolam because the sedative effect achieved with this combination was much greater than that which could be expected from a simple additive response of both sedatives. This sedative combination may be a widely available and valuable for chemical restraint in pigs.

Analgesia↗
PubMed1993

Antagonistic effects of atipamezole and flumazenil on medetomidine-midazolam induced sedation in laboratory pigs.

Antagonistic effects of atipamezole (80, 160 and 240 micrograms/kg, im), and flumazenil (100 micrograms/kg, iv) or atipamezole (80 micrograms/kg) and flumazenil (100 micrograms/kg) on medetomidine-midazolam induced sedation were evaluated in laboratory pigs. Atipamezole at each dose effectively reversed sedation, and the arousal time, standing time and total recovery time were significantly shortened. The optimal action of atipamezole was seen at a dose of 160 micrograms/kg. At this dose recovery from the sedation was quick and smooth, and adverse effects such as hyperactivity or tachycardia were minimal. Flumazenil reversed sedation temporary, but the pigs went back to moderate sedation soon after arousal. The combination of atipamezole and flumazenil most effectively reversed the sedation, however atipamezole (160 micrograms/kg) alone was thought to be practically potent enough to antagonize sedation induced by medetomidine-midazolam in laboratory pigs.

Adrenergic alpha-Antagonists↗
PubMed1993

[Urinary hCG beta-core fragment as a tumor marker for bladder cancer].

Human chorionic gonadotropin (hCG) is a highly specific tumor marker or trophoblastic neoplasms. Also in patients with non-trophoblastic tumors, hCG beta-related material has been frequently demonstrated in their urine. This material was termed beta-core fragment (beta-CF) since it is recognized by hCG beta-core directed antisera but not by hCG beta-carboxyterminal peptide (CTP) directed antisera. We measured the concentration of beta-CF in the urinary samples from patients with urothelial tumors and studied its clinical usefulness as a tumor marker. The concentration of beta-CF was expressed as ng/mg of creatinine in the urine and the cut-off value was 0.1 ng/mg.Cr. Thirty (61.2%) of 49 patients with bladder carcinoma had raised beta-CF levels and the positive rates were dependent upon pathological grade (25.0, 33.3 and 82.8% at G1, G2 and G3, respectively). The elevated urinary beta-CF were also detected in 5 of 7 patients with upper urinary tract carcinoma. However, there was no elevated urinary beta-CF level in prostate carcinoma. Serial determination in 13 patients with elevated beta-CF level prior to therapy showed that 12 patients had decreased concentrations after successful treatment, but 1 patient with persistently elevated urinary beta-CF level after treatment subsequently relapsed. The determination of urinary beta-CF may provide a useful tool in identifying and monitoring the response to treatment in patients with carcinomas of the bladder and the upper urinary tract.

Adult↗
PubMed1992

Magnetic resonance imaging of Krukenberg tumor from gastric cancer.

The magnetic resonance imaging (MRI) findings in a 42-year-old woman with a giant Krukenberg tumor from gastric cancer are reported. The macroscopic features of the Krukenberg tumor resulting from gastric cancer were clearly and precisely shown on MRI. Furthermore, MRI was more useful than ultrasonography or CT for determining the origin and further tissue characterization of the tumor. These findings suggest that MRI can be especially useful in the evaluation of giant ovarian tumors as in the present case.

Adenocarcinoma, Mucinous↗