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Biomedical subjects

T Yoshioka

Publications and source records attributed to T Yoshioka.

At least 181 records · Page 10Linked to original sources
PubMed1999

Proteoglycan core protein in human urine and its possible role on calcium oxalate urolithiasis.

BACKGROUND: There are only a few papers reporting on the role of proteoglycan core protein in calcium oxalate stone formation. The present study was carried out to investigate the role of core protein of proteoglycan in human urine on calcium oxalate (CaOx) crystallization. METHODS: Proteoglycans were collected from whole human urine. The covalently bound glycosaminoglycans (GAG) of proteoglycans were then digested by GAG lyase. The inhibitory activity on CaOx crystal growth in vitro was measured before and after enzyme digestion of proteoglycans. Sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of the core protein of proteoglycans and the analysis of amino acid sequence were performed. RESULTS: The core protein showed significant inhibitory activity on CaOx crystal growth, which scarcely changed when compared with that of proteoglycans before enzyme digestion. The SDS-PAGE revealed that the core protein was a single unit with a molecular weight of 26 kDa and amino acid sequencing demonstrated high homology to interalpha-trypsin inhibitor (ITI) light chain (bikunin) with Kunitz inhibitor domain as a core protein. CONCLUSIONS: The results suggested that human urine contains proteoglycans and a major part of them is ITI light chain (bikunin). The Kunitz inhibitor domain, a core protein of bikunin, has significant inhibitory activity on CaOx crystallization without GAG bound covalently to the core protein.

Adult↗
PubMed1999

Role of Ca(2+)-ATPase in spontaneous oscillations of cytosolic free Ca2+ in GH3 rat pituitary cells.

The relative contribution of voltage-sensitive Ca2+ channels, Ca(2+)-ATPases, and Ca2+ release from intracellular stores to spontaneous oscillations in cytosolic free Ca2+ concentration ([Ca2+]i) observed in secretory cells is not well characterized owing to a lack of specific inhibitors for a novel thapsigargin (Tg)-insensitive Ca(2+)-ATPase expressed in these cells. We show that spontaneous [Ca2+]i oscillations in GH3 cells were unaffected by Ca2+ depletion in inositol-1,4,5-trisphosphate (IP3)-sensitive Ca2+ stores by the treatment of Tg, but could be initiated by application of caffeine. Moreover, we demonstrate for the first time that these spontaneous [Ca2+]i oscillations were highly temperature dependent. Decreasing the temperature from 22 to 17 degrees C resulted in an increase in the frequency, a reduction in the amplitude, and large inhibition of [Ca2+]i oscillations. Furthermore, the rate of ATP-dependent 45Ca2+ uptake into GH3-derived microsomes was greatly reduced at 17 degrees C. The effect of decreased temperatures on extracellular Ca2+ influx was minor because the frequency and amplitude of spontaneous action potentials, which activate L-type Ca2+ channels, was relatively unchanged at 17 degrees C. These results suggest that in GH3 secretory cells, Ca2+ influx via L-type Ca2+ channels initiates spontaneous [Ca2+]i oscillations, which are then maintained by the combined activity of Ca(2+)-ATPase and Ca(2+)-induced Ca2+ release from Tg/IP3-insensitive intracellular stores.

Animals↗
PubMed1999

FDG PET evaluation of residual masses and regrowth of abdominal lymph node metastases from colon cancer compared with CT during chemotherapy.

Fluorine-18-2-deoxy-2-fluoro-D-glucose (F-18 FDG) PET may be more suitable for follow-up after cancer treatment than other morphologic approaches, because it reflects tumor viability. A patient with abdominal lymph node metastases from colon cancer was followed by CT and F-18 FDG PET during chemotherapy. F-18 FDG PET tumor images changed in accordance with the clinical progress, whereas CT findings were relatively unchanged. This case clearly shows the utility of F-18 FDG PET for follow-up during cancer chemotherapy.

Abdominal Neoplasms↗
PubMed1999

Sclerosing mediastinitis: findings on fluorine-18 fluorodeoxyglucose positron emission tomography.

Whole-body serial positron emission tomography scanning was done using fluorine-18 fluorodeoxyglucose (F-18 FDG) in a patient with a mediastinal mass. Uptake correlated well with the clinical symptoms and aggressiveness of the disease. Based on the F-18 FDG findings, a biopsy specimen was taken from the active region of the mass, which confirmed the diagnosis of sclerosing mediastinitis.

Biopsy↗
PubMed1999

Granulocyte colony-stimulating factor ameliorates life-threatening infections after combined therapy with barbiturates and mild hypothermia in patients with severe head injuries.

OBJECTIVE: The objective of this study was to clarify the effects of recombinant human granulocyte colony-stimulating factor (rhG-CSF) administration on infections in patients with severe head injuries after combined therapy with high-dose barbiturates and mild hypothermia. PATIENTS AND METHODS: Since 1996, we have administered rhG-CSF to eight patients with severe head injuries for 5 days (group G). Their treatment results were compared with those of 22 patients cared for earlier without rhG-CSF treatment (group N). All patients in both groups met the criteria of total leukocyte count (TLC) less than 5,000/mm3, C-reactive protein (CRP) over 10 mg/dL, and the presence of an infectious complication. Changes in the TLC, CRP, respiratory index, intracranial pressure, and infectious condition were evaluated in both groups. In addition, the nucleated cell count and differentiation from bone marrow aspiration, neutrophil functions, serum concentrations of interleukin-6, and plasma concentration of leukocyte elastase were evaluated in group G. RESULTS: In group G, TLC, nucleated cell count, and neutrophil functions significantly increased, whereas CRP, respiratory index, and interleukin-6 decreased reciprocally. There was no deterioration of intracranial pressure and leukocyte elastase. Consequently, seven of the eight patients in group G recovered from life-threatening infections, and none of the eight patients died. However, in group N, CRP and respiratory index remained high and TLC did not increase as much as it did in group G. Infections continued after 5 days in 17 of the 22 patients, 7 of whom died from severe infections during hospitalization. CONCLUSION: Administration of rhG-CSF ameliorated life-threatening infections without causing lung injury or increasing brain swelling in patients with severe head injuries who were treated with combined therapy involving high-dose barbiturates and mild hypothermia.

Adolescent↗
PubMed1999

Triolein-induced pulmonary embolization and increased microvascular permeability in isolated perfused rat lungs.

BACKGROUND: The pathophysiologic mechanism of the fat embolism syndrome is poorly understood. This study was designed to determine the effects of fat emboli on pulmonary vasculature. METHOD: Triolein was infused into isolated rat lungs perfused with Krebs-Henseleit buffer. Pulmonary arterial pressure and microvascular permeability (Kf) were measured at baseline and 20 minutes after the triolein infusion. RESULT: The 99% triolein produced dose-dependent increases in both pulmonary arterial pressure and Kf. The 65% triolein, containing free fatty acid, resulted in a greater increase in Kf. Pretreatment with indomethacin attenuated the increase in Kf after 65% triolein but not after 99% triolein. CONCLUSION: Pure triolein induced mainly embolization in the pulmonary vasculature, and 65% triolein caused embolization and subsequently increased vascular permeability, which are, at least in part, mediated by the action of cyclooxygenase products. Free fatty acids might induce permeability edema by means of a cyclooxygenase-dependent mechanism. We conclude that triolein-induced increases in pulmonary arterial pressure and Kf in isolated rat lungs provides a useful model of acute lung injury by fat embolism.

1-Methyl-3-isobutylxanthine↗
PubMed1999

Antitumor efficacy of hypothemycin, a new Ras-signaling inhibitor.

We have devised a new drug screening assay to discover anti-cancer drugs which inhibit Ras-mediated cellular signals, by utilizing a Ras-responsive element (RRE)-driven reporter gene system. We found that hypothemycin, an anti-bacterial, reduces RRE-dependent transcription. Treatment of tumor cells with hypothemycin resulted in reduced expression of Ras-inducible genes, including MMP (matrix metalloproteinase)-1, MMP-9, transforming growth factor-beta (TGF-beta), and vascular endothelial growth factor (VEGF), but not that of the constitutively expressed gene, MMP-2. The results of zymography demonstrated that hypothemycin reduced the production of MMP-9 and MMP-3, another Ras-inducible MMP, in the culture medium. Hypothemycin selectively inhibits anchorage-independent growth of Ras-transformed cells in comparison with anchorage-dependent growth. These findings suggest that hypothemycin inhibits Ras-mediated cellular signaling. Daily treatment of tumor-bearing mice with hypothemycin resulted in significant inhibition of tumor growth. Since MMP-1, MMP-3 and MMP-9 play important roles in tumor invasion and TGF-beta and VEGF are involved in tumor angiogenesis, hypothemycin is considered to be an example of a new class of antitumor drugs, whose antitumor efficacy can be at least partly attributed to inhibition of Ras-inducible genes.

3T3 Cells↗
PubMed1999

Combination chemotherapy with nedaplatin and cyclophosphamide in human ovarian cancer model.

The antitumor efficacy of the combination of nedaplatin (NDP) with cyclophosphamide (CPM) was evaluated using human ovarian cancer models. Since NDP has been found to have greater antitumor activity and lower nephrotoxicity than cisplatin (CDDP), we also compared the antitumor activity of NDP plus CPM with that of CDDP plus CPM. Increasing doses of NDP (16.5, 33 and 66 mg/kg as a total dose) and a fixed amount of CPM (174 or 348 mg/kg as a total dose) were injected three times at intervals of 7 days via the tail vein into mice implanted with RMUG-S, OC9-JCK or KF-28 human ovarian cancer. Simultaneous administration of NDP with CPM resulted in markedly enhanced inhibition of tumor growth for all cancers tested. The growth inhibition and survival effect of the combination therapy of NDP with CPM against KF-28 and OC9-JCK were as potent as those of CDDP plus CPM. Neither increased hematotoxicity nor a significant difference in maximum concentration, half time or area under the curve of platinum or CPM in plasma between the single and combined treatment was found. These results suggest that the combination of NDP with CPM may be clinically effective.

Animals↗
PubMed1999

[Imported trichinellosis with severe myositis--report of a case].

A 38-year-old Japanese male who had traveled in China from September 13 to October 5, 1997, developed fever and severe conjunctivitis from October 20. After he was hospitalized in Kyoto City Hospital for persistent high fever on October 29, he developed muscular weakness and dysphagia which continued for two weeks. An electromyogram showed a myogenic pattern, and laboratory findings showed significant elevation of serum enzyme levels of muscle origin: CPK, 3,095 IU/l; aldorase, 195 IU/l; myoglobin, 7,570 ng/ml, and myoglobinuria, 94,700 ng/ml. The WBC was 10,800/microliter with 45% eosinophils. Muscular biopsy showed degeneration of muscle fibers with infiltration of macrophages and lymphocytes. On further inquiry, it was revealed that the patient had eaten smoked bear meat in China on September 30, three weeks prior to the onset of symptoms. A dot-ELISA serologic test for parasites was positive for Trichinella. Further, a coiled 1.2 mm long Trichinella larve was recovered from approximately 100 mg of frozen biopsied muscle by an enzyme digestion method. Mebendazole was given to the patient at a dosage of 200 mg/day for seven days. CPK levels were normalized within 3 days of the beginning of the treatment, and he was discharged without any symptoms. Physicians must be aware of trichinellosis and should include it in their differential diagnosis when examining patients with myositis and eosinophilia of unknown origin.

Adult↗
PubMed1999

Myonuclear domain and myosin phenotype in human soleus after bed rest with or without loading.

After 2 or 4 mo of bed rest (6 degrees head-down tilt) and 1 mo of ambulation, there was a tendency toward a higher percentage of fibers expressing fast myosin heavy chain (MHC) isoforms and a de novo appearance of fibers coexpressing type I+IIa+IIx and IIa+IIx MHC in human soleus fibers. After 2 and 4 mo of bed rest, the mean size of type I fibers decreased by 12 (P > 0.05) and 39%, respectively. Because myonuclear number/mm of fiber length was unchanged, myonuclear domain was smaller after bed rest than before. The mean size and myonuclear domain of type I fibers were largest after 1 mo of recovery. The effects of wearing an antigravity device (Penguin suit), which had a modest but continuous resistance at the knee and ankle (Penguin-1) or knee resistance without loading on the ankle (Penguin-2), for 10 consecutive h/day were determined during 2 mo of bed rest. Mean fiber sizes in Penguin-1, but not Penguin-2, group were maintained at or above pre-bed-rest levels, whereas neither group showed phenotype changes. Myonuclear domain in type I fibers was larger in Penguin-1 and smaller in Penguin-2 group post- compared with pre-bed rest, indicating that a single daily 10-h bout of modest muscle loading can prevent bed-rest-induced soleus fiber atrophy but has minimal effect on myosin phenotype. The specific adaptive cellular strategies involved may be a function of the duration and magnitude of the adaptive stimulus as well as the immediate activity history of the fiber before the newly changed functional demands.

Adult↗
PubMed1999

Quantitative examinations of internal representations for arm trajectory planning: minimum commanded torque change model.

Quantitative examinations of internal representations for arm trajectory planning: minimum commanded torque change model. A number of invariant features of multijoint planar reaching movements have been observed in measured hand trajectories. These features include roughly straight hand paths and bell-shaped speed profiles where the trajectory curvatures between transverse and radial movements have been found to be different. For quantitative and statistical investigations, we obtained a large amount of trajectory data within a wide range of the workspace in the horizontal and sagittal planes (400 trajectories for each subject). A pair of movements within the horizontal and sagittal planes was set to be equivalent in the elbow and shoulder flexion/extension. The trajectory curvatures of the corresponding pair in these planes were almost the same. Moreover, these curvatures can be accurately reproduced with a linear regression from the summation of rotations in the elbow and shoulder joints. This means that trajectory curvatures systematically depend on the movement location and direction represented in the intrinsic body coordinates. We then examined the following four candidates as planning spaces and the four corresponding computational models for trajectory planning. The candidates were as follows: the minimum hand jerk model in an extrinsic-kinematic space, the minimum angle jerk model in an intrinsic-kinematic space, the minimum torque change model in an intrinsic-dynamic-mechanical space, and the minimum commanded torque change model in an intrinsic-dynamic-neural space. The minimum commanded torque change model, which is proposed here as a computable version of the minimum motor command change model, reproduced actual trajectories best for curvature, position, velocity, acceleration, and torque. The model's prediction that the longer the duration of the movement the larger the trajectory curvature was also confirmed. Movements passing through via-points in the horizontal plane were also measured, and they converged to those predicted by the minimum commanded torque change model with training. Our results indicated that the brain may plan, and learn to plan, the optimal trajectory in the intrinsic coordinates considering arm and muscle dynamics and using representations for motor commands controlling muscle tensions.

Adult↗
PubMed1999

Effects of milk and colostrum on superoxide generation of oral polymorphonuclear neutrophils and the changes that occur during storage at low temperature.

Human oral polymorphonuclear neutrophils (OPMN) generate reactive oxygen species even in the absence of stimulants. Because OPMN from newborn babies are exposed to colostrum and mature milk, the biological properties of these cells including the generation of reactive oxygen species might possibly be affected by the constituents of colostrum and milk. The present work reports the effects of colostrum and mature milk, including the effects of storage at low temperature, on superoxide generation by OPMN. Fresh colostrum and mature milk did not affect either endogenous or formyl-methionyl-leucyl-phenylalanine-induced generation of superoxide by OPMN. However, superoxide generation stimulated by phorbol myristate acetate or arachidonic acid was inhibited by colostrum and mature milk presumably due to binding of the ligands to milk proteins. During the storage of milk at 4 degrees C, free forms of unsaturated long-chain fatty acids increased, and there was concomitant increase in the ability of milk to generate superoxide radicals in OPMN. Kinetic analysis suggested that colostrum and mature milk regulate superoxide generation by OPMN, thereby modulating the bactericidal activity of these cells in the oral cavity.

Animals↗
PubMed1999

Geranylgeranylacetone induces apoptosis in HL-60 cells.

Geranylgeranylacetone (GGA) induces apoptosis in human leukemia HL-60 cells in a dose- and time-dependent manner. This effect was completely prevented by the pan-caspase inhibitor z-Val-Ala-Asp(OMe) fluoromethylketone, thereby implicating the caspase cascade in the process. Prior to DNA fragmentation, GGA treatment markedly activated caspase-3(-like) proteases, which might be responsible for the observed apoptosis. In addition, GGA treatment interfered with the processing and membrane localization of Rap1 and Ras, and these changes may be a result of apoptosis. Moreover, nitric oxide donors significantly accentuated the GGA-induced apoptosis, suggesting that the apoptotic pathway induced by GGA might be regulated by a redox-sensitive mechanism. Taken together, these data suggest that the isoprenoid, GGA, is an effective inducer of apoptotic cell death in HL-60 cells.

Amino Acid Chloromethyl Ketones↗
PubMed1999

Prolongation of the effective duration of cytomedical therapy by re-injecting SK2 hybridoma cells microencapsulated within alginate-poly(L)lysine-alginate membranes into human interleukin-6 transgenic mice.

We previously reported that SK2 hybridoma cells that secreted anti-human interleukin-6 (hIL-6) monoclonal antibodies (SK2 mAb) were microencapsulated within alginate-poly(L)lysine-alginate (APA) membranes (APA-SK2 cells) for immunoisolation, and a single intraperitoneal injection of these APA-SK2 cells remarkably improved IgG1 plasmacytosis in hIL-6 transgenic mice (hIL-6 Tgm). However, the duration of the effectiveness of APA-SK2 cells as a cytomedicine was unfortunately limited. In this study, we attempted to re-inject APA-SK2 cells into hIL-6 Tgm for the purpose of prolonging the cytomedical therapy. In hIL-6 Tgm re-injected with APA-SK2 cells, the plasma IgG1 level did not show any increase in 37 week old mice, and their survival time was at least three times longer than those of untreated hIL-6 Tgm. These results suggest that re-injected APA-SK2 cells survived and secreted SK2 mAb in the allogeneic mice. Thus, the limited duration of the cytomedical effects of APA-SK2 cells was probably caused by the disappearance of the inner space of microcapsules for cell proliferation, not by the rejection of the host's immune system. Therefore, if we can regulate the proliferation of the cells microencapsulated within a semipermeable membrane, we may be able to develop a cytomedicine which will continue its function longer after a single injection.

Alginates↗
PubMed1999

Combined cardiac surgery and total thyroidectomy: a case report.

A 65-year-old woman with aortic stenosis, ischemic heart disease, and Graves' disease had complained of effort angina. She then suffered from liver dysfunction due to treatment with antithyroid drugs. One year after the start of radioiodine administration, she demonstrated unstable angina with palpitation and sweating. Laboratory studies revealed a recurrent hyperthyroid state, and a second coronary angiogram revealed progressive ischemic heart disease. Combined coronary artery bypass grafting, aortic valve replacement, and total thyroidectomy were performed. The postoperative course was uneventful without any problems associated with hyperthyroidism or hypothyroidism. Combined cardiac surgery and total thyroidectomy can be performed safely if the perioperative levels of thyroid hormone are maintained at euthyroid or hypothyroid levels.

Aged↗
PubMed1999

Aortic valve replacement for aortic regurgitation in a patient with primary antiphospholipid syndrome.

A 42-year-old woman with the diagnosis of aortic regurgitation was admitted to hospital for surgical treatment. Ten years ago, primary antiphospholipid syndrome had been diagnosed, and she had a history of recurrent spontaneous abortions and deep vein thrombosis. She was suffering from moderate exertional dyspnea and chest pain. Catheter investigation revealed progressive dilatation of the left ventricle and a deterioration of the ejection fraction. The aortic valve was excised and replaced with a mechanical valve. A specimen of the aortic valve showed localized thickening and shrinkage of the midportion and base of each cusp, with vegetation on the surface. These localized, specific findings suggest that another mechanism may be involved in the cardiac valve pathology in patients with primary antiphospholipid syndrome. No hemostatic or thromboembolic problems were encountered after the surgery, and her postoperative course was uneventful.

Adult↗
PubMed1999

Chemical control of Haematobia irritans with 0.5% topical ivermectin solution in cattle.

A field trial was conducted to evaluate the efficacy of a topical formulation of ivermectin administered at the dose of 500 micrograms/kg against horn flies (Haematobia irritans) in cattle. Eighty-eight cattle in four herds naturally exposed to horn flies were used in the trial. Replicates were formed of two herds. Within replicates, one herd was randomly allocated to the untreated control and the other to the ivermectin treatment group. Horn fly counts were taken on the treatment day (Day 0) and on Days 7, 14, 21, 28, and 35 post-treatment. There were no horn flies on any cattle in the treatment group, whereas all the control cattle were continuously infested by horn flies on each examination day.

Administration, Topical↗