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Biomedical subjects

M Yasuda

Publications and source records attributed to M Yasuda.

At least 361 records · Page 20Linked to original sources
PubMed1992

Estimation of the loudness of tinnitus from matching tests.

To correct for the influence of recruitment when the loudness of tinnitus is measured by a balance test in an ear with sensorineural hearing loss, an averaged loudness function was devised, which converts the sensation level (SL) of tinnitus into an estimate of the effective loudness level. This is essentially the same as a phon scale except for the difference in reference level, and is defined as the equivalent SL of the tinnitus as if measured in an ear with a bone-conduction threshold of 0 dB HL at a frequency between 500 Hz and 4000 Hz. Using this function, the median estimated loudness of tinnitus from 301 randomly selected patients was 15 dB 'effective loudness level' with a maximum of more than 60 dB. A nomogram was made for clinical use to determine the effective loudness level easily from the SL of tinnitus and the bone-conduction HTL of the test ear. Although somewhat approximate, the effective loudness level is considered to be an unbiased loudness estimate of tinnitus under the condition that only the SL of tinnitus and the bone-conduction HTL are available, and makes it easier to appreciate the actual loudness compared with a complex loudness unit such as on the sone scale.

Adolescent↗
PubMed1992

Effects of ultraviolet-inactivated feline leukemia virus on the production of alpha/beta interferon by feline peripheral blood mononuclear cells.

The effects of ultraviolet-inactivated feline leukemia virus (UV-FeLV) on the production of alpha and/or beta interferon (IFN) by mononuclear cells stimulated with the Newcastle disease virus (IFN-NDV) was investigated. The production of IFN-NDV and gamma IFN was suppressed by 50% as compared to the control in the presence of 200 ng/ml or 200 micrograms/ml of UV-FeLV, respectively. The presence of UV-FeLV decreased the rate of the production, but the time to reach the plateau of the IFN activity in the culture supernatant was not shortened in both IFNs. It was suggested that the suppressive effects of UV-FeLV against both IFNs were through rather similar mechanisms. The suppressive effects of UV-FeLV on IFN-NDV production was most evident in the cultures to which UV-FeLV was added at the early stages of the culture, and could not be demonstrated when UV-FeLV was added 8 hr after initiation of the culture. These data therefore indicate that non-infectious feline leukemia viral particles can modify the production of feline IFNs by peripheral blood mononuclear cells.

Animals↗
PubMed1992

An autopsy case of tuberous sclerosis. Histological and immunohistochemical study.

We report an autopsy case of tuberous sclerosis. A 19-year-old Japanese man had shown facial adenoma sebaceum, intractable convulsive seizures and severe mental retardation. Gross inspection of the brain showed a cortical tuber from the orbital frontal lobe to the rhinencephalon of the left side and a few subependymal nodules. Histological examination revealed many cortical tubers in the cerebral hemispheres, a few subependymal nodules with calcification and multifocal clusters of heterotopic cells in the white matter (white matter nodules). In these lesions, massive giant cells with abundant eosinophilic cytoplasm and without Nissl substances were found. Although the size and shape of the giant cells were variable, the majority of them were gemistcytic, ovoid or polygonal. Immunohistochemistry was employed in these lesions using antibodies against neurofilament protein (NFP), glial fibrillary acidic protein (GFAP), vimentin (VM) and myelin basic protein (MBP). In the cortical tuber, the majority of the giant cells were positive for both NFP and VM, but a few were positive for GFAP. All of them were negative for MBP. In the subependymal nodule and white matter nodule, the majority of the giant cells were positive for NFP, but a few were positive for VM, and none were positive for either GFAP and MBP. These findings suggest that the majority of the giant cells may be immature cells toward neuronal series and a few may be those toward astroglial series. These findings also indicate that the giant cells in the subependymal nodule and white matter nodule may be more differentiated than those in the cortical tuber. The nature of the giant cells in tuberous sclerosis is discussed.

Adult↗
PubMed1992

[Metabolism of Ca2+ in myocytes and peroxidation products in ischemia-reperfusion injury under extracorporeal circulation].

The metabolism of calcium ion (Ca2+) in myocytes in ischemia-reperfusion injury under extracorporeal circulation (ECC) was studied by cytochemistry and electron microscopy. Ten mongrel dogs were under ECC with aortic cross-clamping for 120 minutes. A cold GIK crystalloid cardioplegic solution was infused via the aortic root intermittently during ischemia, and the myocardial temperature was maintained at 5-10 degrees C with ice slush. The morphological changes of Ca(2+)-ATPase activity in myocytes were estimated using the "lead citrate method". The activities of mitochondria, which had been temporarily decreased just before reperfusion, increased immediately after reperfusion and decreased again 60 minutes later. Electromicroscopy revealed swelling of mitochondria and laceration of myofibrils as well as intracellular edema 60 minutes after reperfusion. Immediately after reperfusion and 60 minutes later, creatine phosphokinase iso-enzyme (CK-MB) release in coronary sinus blood was significantly (p < 0.01) greater than that before the start of ECC. Anaerobic metabolism immediately after reperfusion was more active than that before aortic cross-clamping, as demonstrated by changes in excess lactate (delta XL) and redox potential (delta Eh) of lactate and pyruvate (delta XL, p < 0.05; delta Eh, p < 0.01). Thus, in ischemia-reperfusion injury, alterations of Ca(2+)-ATPase activity of mitochondria reflect the functional and morphological viability of the myocardium. Immediately and 60 minutes after reperfusion, the level of thiobarbituric acid was significantly (p < 0.01) higher and the level of alpha-tocopherol was significantly (p < 0.01) less than respective levels before the start of ECC.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

[A clinical study of suicidal behavior in schizophrenic patients].

117 subjects admitted to the Department of Emergency and Critical Care Medicine at Sapporo City General Hospital due to suicide attempts between June 1983 and August 1986 were studied. Various aspects of attempted suicide and successful suicide in patients with schizophrenia were compared with those same aspects in patients with other psychiatric conditions. Similarly, 30 patients with schizophrenia who attempted suicide between January 1975 and December 1989 while inpatients or discharged outpatients in the Department of Neuro-Psychiatry at Sapporo City General Hospital were also examined. 1) In both the transverse study in the Department of Emergency and Critical Care Medicine and the longitudinal study in the Department of Neuro-Psychiatry at Sapporo City General Hospital, suicidal behavior in patients with schizophrenia increased significantly over a 5 year period after the onset of the disease. 2) Schizophrenic patients used more lethal methods for suicide (such as a direct and violent injury to the body) than did other psychiatric patients. With regards to body injury method, there was no difference between schizophrenics and other psychiatric patients between the ages of 20 and 30, though significantly more schizophrenics between the ages of 30 and 50 chose a violent body injury method. 3) Schizophrenics attempted suicide more often at any other place out of their houses than did other psychiatric patients (depressives, neurotics, etc.) and normal subjects. The difference between schizophrenics and other psychiatric patients was particularly distinct between the ages of 30 and 50. 4) Most schizophrenic patients who attempted suicide were in an exacerbated period of the illness. Interviews immediately after suicide attempts revealed that most patients attempted suicide against their will, moved by delusional and hallucinatory experiences. It is therefore presumed that most suicide in schizophrenics, even though seemingly unexpected or impulsive, is actually provoked by rapid fluctuation of the psychosis. 5) Positive symptoms reported at the time of attempted suicide included delusion of persecution, imperious auditory hallucinations, hypochondriacal delusions, and delusion of guilt. The abnormal experience which induced suicide attempts generally consisted of delusional perceptions regarding an inability to recover health, hallucinatory commands, and acute self-disruption generated by experiences such as sudden delusional ideas. These drove the patients toward suicide. 6) Most suicide attempts were within several days or several hours of abrupt symptom exacerbation. It is noteworthy that these attempts were clustered within limited periods of time. Overt suicidal tendencies continued for several months, suggesting that there is a period in which suicide may be easily induced.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1991

Iron as a possible aggravating factor for osteopathy in itai-itai disease, a disease associated with chronic cadmium intoxication.

Itai-itai disease is thought to be the result of chronic cadmium (Cd) intoxication. We examined 23 autopsy cases of itai-itai disease and 18 cases of sudden death as controls. Urine and blood samples from 10 patients were collected before they died and revealed the presence of severe anemia and renal tubular injuries. Undecalcified sections of iliac bone were stained with Aluminon reagent, and ammonium salt of aurintricarboxylic acid, and Prussian blue reagent in all cases of itai-itai disease. These two reagents reacted at the same mineralization fronts. X-ray microanalysis revealed the presence of iron at mineralization fronts in itai-itai disease. Five patients showed evidence of hemosiderosis in the liver, spleen, and pancreas, probably as a result of post transfusion iron overload. Renal calculi and calcified aortic walls were also stained with Prussian blue reagent in several patients. Neither ferritin nor transferrin were visualized at mineralization fronts in itai-itai disease by immunohistochemical staining. These results suggest that iron is bound to calcium or to calcium phosphate by a physicochemical reaction. A marked osteomalacia was observed in 10 cases of itai-itai disease by histomorphometry. Regression analyses of data from cases of itai-itai disease suggested that an Aluminon-positive metal inhibited mineralization and that renal tubules were injured. Since bone Cd levels were increased in itai-itai disease, it is likely that renal tubules were injured by exposure to Cd. Therefore, stainable bone iron is another possible aggravating factor for osteopathy in itai-itai disease, and a synergistic effect between iron and Cd on mineralization is proposed.

Aged↗
PubMed1991

Actin bundles on the right side in the caudal part of the heart tube play a role in dextro-looping in the embryonic chick heart.

The role of actin bundles on the heart looping of chick embryos was examined by using cytochalasin B, which binds to the barbed end of actin filaments and inhibits association of the subunits. It was applied to embryos cultured according to New's method. Looping did not occur when cytochalasin B was applied diffusely in the medium. Further, we disorganized actin bundles in a limited part of the heart tube to examine the role of actin bundles in each part in asymmetry formation. A small crystal of cytochalasin B was applied to the caudal part of the heart tube on either the left or right side. The disorganization of actin bundles on the left side resulted in the right-bending of the heart, an initial sign of dextro-looping (normal pattern), and right side disorganization resulted in left-bending. We suggest that actin bundles on the right side of the caudal part of a heart tube generate tension and cause dextro-looping. Embryos whose hearts bent to the right rotated their heads to the right, and embryos with left-bent-hearts rotated their heads to the left. The rotation of the heart tube may therefore decide in which direction the body axis rotates.

Actins↗
PubMed1991

Multicentric reticulohistiocytosis associated with subclinical Sjögren's syndrome.

A case of multicentric reticulohistiocytosis in a 60-year-old Japanese woman associated with subclinical Sjögren's syndrome is presented. The clinical features along with the light microscopic studies are commented. Partial improvement of the skin lesions and tendon sheath swelling was achieved after treatment with cyclophosphamide but the patient's general condition remained unchanged. Taking the rarity of multicentric reticulohistiocytosis into account, coexistence of these two conditions in the present and previously reported cases suggests that an autoimmune mechanism may play a part in the pathogenesis of multicentric reticulohistiocytosis.

Cyclophosphamide↗
PubMed1991

Effects of colony-stimulating factors on proliferation and activation of synovial cells.

Joint synovium of patients with rheumatoid arthritis plays an important role in initiation and progress of joint diseases. Proliferation and activation of synovial cells, including macrophages, are modulated by various cytokines and arachidoic acid metabolites. Two kinds of cytokines; granulocyte/macrophage colony-stimulating factors (GM-CSF), and monocyte/macrophage colony-stimulating factor (M-CSF) induce the proliferation or activation of monocyte/macrophages, and their progenitor cells or other stromal cells in bone marrow. We investigated the effects of GM-CSF and M-CSF on synovial cells. GM-CSF stimulated the proliferation of synovial cells and its effect was enhanced by the presence of indomethacin, like that of a potent stimulator of synovial cells, interleukin-1 beta (IL-1 beta). But GM-CSF did not induce the production of IL-1 beta. M-CSF neither stimulated the proliferation of synovial cells nor induced production of IL-1 beta by synovial cells. It was suggested that GM-CSF played some role in the proliferation of synovial cells of the joints.

Cell Division↗
PubMed1991

Plasma levels of platelet-derived growth factor in normal subjects and patients with ischemic heart disease.

Plasma levels of platelet-derived growth factor (PDGF) were measured in 24 normal control subjects, 31 patients with stable angina pectoris, 25 patients with unstable angina pectoris, and 31 patients with acute myocardial infarction (AMI) by a sensitive direct radioimmunoassay. The plasma PDGF level in normal control subjects was 273 +/- 25 pg/ml; there was no significant correlation between the plasma PDGF level and age. Plasma PDGF levels in patients with unstable angina pectoris and acute myocardial infarction were significantly lower than those in normal control subjects and patients with stable angina pectoris (p less than 0.05). In patients with acute myocardial infarction the plasma PDGF level in the chronic phase was significantly higher than that in the acute phase (p less than 0.05). These observations raise the possibility that PDGF is involved in the pathophysiology of ischemic heart disease.

Adult↗
PubMed1991

Dealkylation rates of O6-alkyldeoxyguanosine, O4-alkylthymidine and related compounds in an alkyl-transfer system.

Bacterial O6-alkylguanine-DNA alkyltransferase (AGT) removes alkyl group from O6-alkylguanine and O4-alkylthymine residues in DNA, both of which are considered to be DNA damages most related to the induction of cancer and/or mutation. The repair process involves alkyl-transfer of an O-alkyl group to the active site of the enzyme, where an SH-group of cysteine residue plays the role of alkyl acceptor. In order to elucidate the chemical characteristics of substrates for this enzyme, dealkylation rates of O6-alkyldeoxyguanosine, O4-alkylthymidine and related compounds were measured using an alkyl-transfer system. Thiophenol-triethylamine system was employed as an alkyl acceptor and twenty-one O-alkyl compounds were tested. Dealkylation proceeded with pseudo first order kinetics. The half-life of O6-methyldeoxyguanosine (MedG) was 122 h and no remarkable dependence on N-9 substituents (H, CH3 and deoxyribose) was observed. A compound lacking 2-NH2 group underwent demethylation about three times faster than O6-methylguanines did, while, a compound lacking imidazole moiety underwent demethylation about 2.5 times more slowly. The half-life of O4-methylthymidine (MedT) was 38 h and no remarkable dependence on N-1 (H, CH3 and deoxyribose) and C-5 (H and CH3) substituents was observed. Deethylation proceeded much more slowly than demethylation. Substitution of selenophenol for thiophenol resulted in a 4.5 times faster MedG demethylation rate. Demethylation rates were moderately correlated with values for NMR chemical shift of CH3 group, an indicator of electron density, although the correlation curves of a series of MedG and MedT derivatives were quite different. This result suggests that some different rate-determining factors other than electron density are playing a role. These findings may be of help in resolving the details of the mechanisms of enzymic repair by bacterial and mammalian AGT.

Alkylation↗
PubMed1991

Circulating immunoreactive endothelin in patients undergoing percutaneous transluminal coronary angioplasty.

Circulating immunoreactive endothelin (ir-ET) in the coronary sinus (CS) and the femoral artery (Ao) was measured in patients who underwent percutaneous transluminal coronary angioplasty (PTCA). Plasma ir-ET level in the CS was significantly increased from 1.6 +/- 0.8 pg/mL to 2.0 +/- 1.0 pg/mL after PTCA (P less than .05). Plasma ir-ET level in the Ao tended to increase after PTCA, but it was not significant. Plasma ir-ET level in the CS was not related to the plasma thromboglobulin level, plasma thrombin-antithrombin complex level, mean blood pressure, or heart rate. These results suggest that the increase of plasma ir-ET level in the CS may be associated with the coronary endothelial injury by PTCA.

Adult↗
PubMed1991

Vitamin E in gastric mucosal injury induced by ischemia-reperfusion.

To clarify the relationship among vitamin E, oxygen radicals, and lipid peroxidation in ischemia-reperfusion, we produced an experimental model of gastric mucosal injury in rats by ischemia-reperfusion with clamping of the celiac artery and measurements of the area of gastric erosion, thiobarbituric acid (TBA)-reactive substances, and alpha-tocopherol in serum and gastric mucosa during ischemia-reperfusion. The area of gastric erosions and TBA-reactive substances in gastric mucosa were significantly increased after 30 and 60 min of reperfusion. The serum alpha-tocopherol-cholesterol ratio and gastric mucosal alpha-tocopherol were significantly decreased after 30 and 60 min of reperfusion. On the other hand, in vitamin E-deficient rats, gastric mucosal injury induced by ischemia-reperfusion was more severe than that in vitamin E-nondeficient rats. These results indicate that vitamin E is consumed in the process of lipid peroxidation induced by oxygen radicals in ischemia-reperfusion to prevent the development of tissue damage.

Animals↗
PubMed1991

Effect of estrogen and progesterone on the growth of human ovarian dysgerminoma heterotransplanted to athymic nude mice.

The effects of estrogen and progesterone on the growth of dysgerminoma of ovary heterotransplanted to ovariectomized athymic nude mice (OVX-NUs) were examined. OVX-NUs were divided into 6 groups and a subcutaneous injection of either 1 micrograms or 10 micrograms of estradiol (E1 or E10), 0.1 mg or 1 mg of progesterone (P0.1 or P1), or a combination treatment of E1 and P1 (E1 + P1), or sesame oil as a vehicle control (oil) was given every other day for 2 weeks. Tumor size was recorded every day and the volume doubling time (VDT) was calculated. Tumor bearing OVX-NUs were killed on day 21 and tumor tissue was excised for retransplantation, histological examination and cytosol receptor assay. E10 treatment accelerated tumor growth and shortened VDT to 25 hours compared to 44 hours for the control group. P1 treatment delayed the tumor growth (VDT: 71 hrs) and E1 + P1 treatment further inhibited it (VDT: 197 hrs). E1 or P0.1 did not have any effect on the tumor growth. The levels of both the estrogen receptor (ER) and progesterone receptor (PR) of the original tumor were 5 fmol/mg protein, respectively. Hormone treatment had no remarkable effect, except for a significant increase in PR after estrogen treatment and this result seems to be responsible for the enhanced inhibitory effect of E + P on tumor growth. These effects were also observed histologically. In conclusion, the dysgerminoma used in this study was sex steroid hormone dependent and P alone or in combination with E could be a choice for the treatment of such ovarian dysgerminoma.

Analysis of Variance↗
PubMed1991

Pheochromocytoma with electrocardiographic change mimicking angina pectoris, and cyclic change in direct arterial pressure--a case report.

A forty-two-year-old man was admitted because of chest pain. Electrocardiograms at admission showed horizontal ST depression in leads, II, III, aVF, V4, V5, and V6. Direct blood pressure monitoring revealed cyclic change between 160/100 mmHg and 70/50 mmHg and heart rate between 80/sec and 120/sec at fifteen minute intervals. The plasma norepinephrine and epinephrine concentrations were elevated during the episodes of hypertension. Pheochromocytoma was found in the right adrenal gland. These cyclic changes in blood pressure and heart rate are an aid for diagnosis.

Adrenal Gland Neoplasms↗
PubMed1991

Two-dimensional and Doppler echocardiographic findings in a case of subaortic "fibrous sac".

We described a 37-year-old man with a subaortic "fibrous sac", admitted for congestive heart failure. On 2-dimensional echocardiography a saccular structure was seen to extend from the left coronary cusp of the aortic valve to the outflow tract of the left ventricle. By color Doppler imaging, a grade 3 aortic regurgitation was recognized. Aortic regurgitant flow was recorded from the left coronary cusp to the saccular lesion. When congestive heart failure became exacerbated, the repeat examination showed the regurgitant flow passing through the perforated bottom of this lesion and reaching the left ventricular cavity. On microscopic examination of the excised valve, capillary proliferation and inflammatory changes were recognized near the annular region of the left coronary cusp. The edge of the valve leaflet and the other 2 cusps were intact. It is likely that our patient had a mycotic aneurysm near the aortic ring. We speculate that aortic regurgitation followed inflammation. It dilated the left ventricular cavity and contributed to congestive heart failure. Inflammation also weakened the tissue near the annulus, causing it to protrude into the subaortic region thus forming a small aneurysm. It may have grown to become a large saccular structure under high aortic pressure. That is, it became a "giant" endocardial pocket with inflammatory process. Finally, the rupture of this sac caused a massive aortic regurgitation, exacerbating congestive heart failure.

Adult↗
PubMed1991

Assessment of superior vena caval blood flow velocity in ischemic heart disease.

In order to evaluate the right atrial function in patients with ischemic heart-disease, we studied the superior vena caval blood flow velocity using pulsed Doppler echocardiography. The subjects included 31 patients with anteroseptal infarction (ANT), 23 with inferior or inferoposterior infarction (INF + POS), 27 with effort angina pectoris (EAP) and 15 with vasospastic angina pectoris (VAP). The systolic peak flow velocity (PFVs) was significantly reduced only in INF + POS compared with those in ANT, EAP and VAP (36.8 +/- 1.8 cm/sec vs 46.9 +/- 2.1 cm/sec, 46.4 +/- 2.1 cm/sec and 42.6 +/- 1.9 cm/sec, p less than 0.05, respectively). No significant difference in diastolic peak flow velocity (PFVd) was found between the 4 groups. PFVs/PFVd was significantly reduced only in INF + POS compared with those in ANT, EAP, and VAP (1.39 +/- 0.05 vs. 1.75 +/- 0.08, 1.76 +/- 0.09, and 1.62 +/- 0.09, p less than 0.05, respectively). These results suggested that INF + POS caused impairment of the right atrial reservoir function.

Analysis of Variance↗