Biomedical subjects

O Sakai

Publications and source records attributed to O Sakai.

At least 217 records · Page 12Linked to original sources

PubMed1990

Hepatic neoplasms: detection with hepatoportal subtraction angiography--a new technique of DSA.

A new technique for hepatic intraarterial digital subtraction angiography (DSA)--hepatoportal subtraction angiography (HPSA)--that emphasizes the enhancement of tumors by suppressing liver parenchymal enhancement has been developed. The tumor detection sensitivity of HPSA was evaluated prospectively in comparison with that of conventional hepatic intraarterial DSA, unenhanced computed tomography (CT) or CT enhanced with iodine-containing contrast material (conventional CT), CT with iodized oil, and ultrasound (US). For 84 detected lesions of hepatoma, the sensitivity of HPSA was 92%, statistically superior to the 71% of hepatic intraarterial DSA (P less than .002), the 42% of US (P less than .001), and the 39% of conventional CT (P less than .001) and nearly the same as the 90% of CT with iodized oil. Among 33 lesions of metastasis, HPSA depicted 91%; conventional CT, 93%; US, 87%; and hepatic intraarterial DSA, 76%. HPSA was more sensitive than hepatic intraarterial DSA, but the difference was not statistically significant. Compared with hepatic intraarterial DSA, HPSA enabled detection of more faintly enhanced tumors, and this technique was considered useful for detecting small hypervascular hepatic tumors.

Adult↗

PubMed1990

[Ca2+]i rises via G protein during regulatory volume decrease in rabbit proximal tubule cells.

Although animal cells swell in hypotonic medium, their volume is subsequently regulated by a net loss of KCl via Ca2(+)-dependent channels. A rise in intracellular free calcium ([Ca2+]i) thus appears to be an initial event in the adaptation of external tonicity, although details of this mechanism are not known. To investigate cell volume regulation, we measured [Ca2+]i (by use of fura-2) and cell diameters in single cells of cultured renal proximal convoluted tubule. We found that a rapid rise in [Ca2+]i occurred after cells were exposed to hypotonic solution (250 mosM) from 95.8 +/- 3.8 to 468.2 +/- 24 nM (n = 16). The rise in [Ca2+]i was not observed in cells exposed to Ca2(+)-free medium, and exposure to isotonic high-K or low-Na medium did not elicit a rise in [Ca2+]i, suggesting that this rise was a result of Ca2+ influx and not via voltage-dependent Ca2+ influx or decrease of Ca2+ efflux via Na(+)-Ca2+ pump. Pretreatment of cells with pertussis toxin dose dependently blocked the rise in [Ca2+]i. The hypotonic solution enhanced accumulations of inositol tris- and tetra-phosphate after a 1-min exposure. Studies that measured cell diameters suggest that recovery of cell volume may include the rise in [Ca2+]i. These data suggest that the regulatory volume decrease of proximal tubule cells involves a pertussis toxin-sensitive guanine nucleotide binding protein-operated Ca2+ influx.

Animals↗

PubMed1990

Drug-induced hypersensitivity nephritis: lymphocyte stimulation testing and renal biopsy in 10 cases.

The pathomorphological and clinical findings were investigated in 10 cases of drug-induced hypersensitivity nephritis. Hypersensitivity due to drugs was strongly suggested by the lymphocyte stimulation test in all patients. The offending drugs included penicillin, cephem derivatives, nonsteroidal anti-inflammatory drugs, and minocycline. All patients developed acute renal failure shortly after administration of regular doses of the drugs. Allergic symptoms plus a raised level of serum IgE or eosinophilia were seen in 7 patients. The remaining 3 patients receiving nonsteroidal anti-inflammatory drugs had no allergic symptoms, but developed severe proteinuria. Eight patients without severe glomerular damage recovered after withdrawal of the offending drugs and temporal dialysis and/or steroid therapy. Renal biopsies revealed tubulitis and tubular epithelial degeneration with interstitial edema as the common characteristic findings. Granulomatous lesions were occasionally observed. Multinucleated giant cells found in the granulomas were positive for LN-3 which is compatible with HLA-DR antigen. The glomeruli appeared normal, except in 2 cases in whom crescentic glomerulonephritis and thrombotic microangiopathy were seen. Our study suggests that the lymphocyte stimulation test and renal biopsy are the most useful means to confirm the diagnosis and provides further evidence for the participation of cell-mediated immunity in the pathogenesis of drug-induced hypersensitivity nephritis.

Acute Kidney Injury↗

PubMed1990

Development of collateral circulation after acute myocardial infarction: its role in preserving left ventricular function.

The present study evaluated the effects of coronary collateral circulation developing after acute myocardial infarction on global and regional left ventricular function during the chronic stage. The study group consisted of 16 patients with initial myocardial infarction having total occlusion of the proximal left anterior descending coronary artery. To eliminate the effects of collateral circulation existing at the onset of infarction, patients with pre-infarction angina were excluded from this study. The patients were categorized in two groups depending on the extent of their collateral circulation (collateral index: CI 0-3): group A--patients with significant collateral circulation (CI = 2 or 3) to the infarct-related coronary artery; group B--patients without significant collateral circulation (CI = 0 or 1). Their heart rate, left ventricular peak systolic and end-diastolic pressures and cardiac index were similar in the two groups. The left ventricular end-systolic volume index in the group B was significantly greater than that in the group A (60 +/- 21 ml/m2 vs 34 +/- 9 ml/m2, p less than 0.05). Left ventricular ejection fraction in the group A was significantly greater than that of the group B (55 +/- 9% vs 39 +/- 15%, p less than 0.05), and a significant difference was observed in the percentage of segment shortening in the infarct area between the groups A and B (10.8 +/- 9.2% vs -0.2 +/- 5.4%, p less than 0.01). It was concluded that coronary collateral circulation which develops after acute myocardial infarction exerts beneficial effects on global and regional left ventricular function during the chronic stage.

Adult↗

PubMed1990

[Significance of collateral circulation in reversible asynergy].

The functional role of collateral circulation in reversible asynergy of the left ventricle was evaluated. Cineventriculograms were obtained before and after the administration of sublingual nitroglycerin (0.3 mg) in 19 patients with complete occlusion of the proximal portion of the left anterior descending coronary artery. In nine patients with well-developed collateral circulation, both left ventricular ejection fraction and regional wall motion were significantly improved by nitroglycerin. By contrast, in 10 patients without significant collateral circulation, there were no detectable changes in both global and regional wall motions before and after nitroglycerin. The left ventricular hemodynamic changes caused by nitroglycerin were comparable in both groups. These findings support the view that the improvement in asynergy caused by nitroglycerin appears to depend mainly on the extent of collateral circulation, rather than on decreases in both preload and afterload.

Aged↗

PubMed1990

Possibility for induction of convulsion by fleroxacin and its disposition in the central nervous system in animals.

Fleroxacin and its metabolites were examined for their possibility of the induction of convulsion in mice, inhibitory activity on GABA receptor binding, and disposition in the central nervous system of mice, rats and dogs. No convulsion was evoked in mice at high oral combination doses of fleroxacin and fenbufen. Brain-to-serum concentration ratios of fleroxacin after oral dose were 0.13 in mice, 0.19 in rats and 0.28 in dogs. Rats showed no accumulation of fleroxacin in brain and similar elimination from brain to that from serum after the oral dose. Dogs exhibited the similar distribution of fleroxacin into various brain regions. The inhibitory effect of fleroxacin on GABA receptor binding was relatively weak and slightly potentiated in the presence of 4-biphenylacetic acid. Demethyl fleroxacin showed more potent inhibitory activity on GABA receptor binding and potentiation with 4-biphenylacetic acid. The combination of intravenous demethyl fleroxacin and oral fenbufen showed no convulsion in mice. Fleroxacin N-oxide showed only slight inhibitory activity on GABA receptor binding, being not influenced with 4-biphenylacetic acid.

Animals↗

PubMed1990

[Serum beta 2-microglobulin concentration and its removal in patients treated with continuous ambulatory peritoneal dialysis].

This study was performed to clarify serum beta-2 microglobulin (beta 2-M) level and its change in 50 CAPD and 56 HD patients. There was significant correlation between duration of dialysis and serum beta 2-M level in CAPD and HD patients treated under 12 months, but no correlation in those treated over 12 months. Serum beta 2-M level was 33.5 +/- 9.1 mg/l in 45 CAPD patients treated over 12 months, and 46.2 +/- 21.1 mg/l in 35 HD patients. In 26 CAPD patients treated over 12 months, clearance and removal of beta 2-M were 1.0 +/- 0.3 ml/min and 43.0 +/- 17.8 mg/day. There was significant correlation between dwell time and beta 2-M removal (p less than 0.01), and these results suggested beta 2-M was removed by diffusion. Because CAPD treatment can lower serum beta 2-M level compared to HD, there is possibility that CAPD is useful at prevention of dialysis associated amyloidosis.

Adult↗

PubMed1990

Effects of low protein diet in puromycin aminonucleoside-induced nephrotic rats.

Wistar rats were injected with puromycin aminonucleoside (PAN) to induce massive proteinuria and were raised on a low protein diet to determine whether the urinary protein excretion might be reduced. Although PAN nephrotic rats fed with a normal protein diet containing 20% protein (group A) did not show any reduction of their urinary protein excretion, PAN rats fed with a low protein diet containing 6% protein (group B) revealed a marked reduction at day 9 of the present study in comparison with group A. The total serum protein levels were low in groups A and B as compared to group C, the non-treated control. However, group A recovered to normal levels at day 13. In terms of the absolute amount of oral protein intake, marked differences were observed between groups B and C, but little difference was observed between groups A and C. The body weight in all three groups was decreased at 8 days after the start of this study. The serum levels of creatinine were elevated to 1.1 +/- 0.3 mg/dl and 1.0 +/- 0.2 mg/dl in groups A and B, respectively, on day 7, but abruptly recovered to normal levels by day 12. These data indicate that the decreased urinary protein excretion in group B might be dependent on the total protein volume intake, and not on the renal function nor serum levels of total protein.

Animals↗

PubMed1990

A case of nephrotic syndrome due to alpha-mercaptopropionyl glycine in a patient with familial cystinuria.

A 26-year-old male with nephrotic syndrome (NS) due to alpha-mercaptopropionyl glycine (MPG) is described. In March, 1988, he was diagnosed as having familial cystinuria after receiving urolithiasis treatment since December, 1985. Massive proteinuria and slight pedal edema were noted. Nephrotic syndrome was suggested and renal biopsy was performed. The renal pathological finding demonstrated membranous glomerulonephritis (MN) at stage I. This case was defined as NS clinically associated with MPG, and glucocorticoid intake was initiated. The response to the glucocorticoids was fairly good with no clinical problems after discontinuation of MPG, and the cystinuria was maintained with alkaline medication. The patient's parents and younger brother were suggested and confirmed to have cystinuria based on urinary aminogram analysis, but displayed no symptoms. We present a rare case of NS due to MPG therapy in a patient with familial cystinuria. However, the mechanism of onset remains unclear.

Adult↗

PubMed1990

[Fulminant hepatic failure induced by intermediate dose methotrexate in a case of non-Hodgkin's lymphoma].

Methotrexate (MTX) is frequently used as an antifolics agent in many malignant neoplasms such as leukemia, lymphoma and osteosarcoma. The major side effects of MTX are liver and renal damages, bone marrow suppression and so on. But careful management and citrovorum factor rescue could decrease the incidence and degree of these side effects. In this report, we described a patient with non-Hodgkin's lymphoma who developed and died of fulminant hepatic failure soon after the administration of intermediate dose MTX. Serological tests for HB virus were not changed throughout, and lymphocyte stimulation test for MTX was strongly positive. His autopsy revealed no inflammatory cell infiltration into the liver, but marked biliary congestion which is a distinctive feature of drug induced hepatitis. From above results, it was suggested that nature of this fulminant hepatic failure was an allergic reaction to MTX. There is no previous report which is concerning about MTX and fetal drug related hepatic failure.

Adult↗

PubMed1990

[Allopurinol induced aplastic anemia in a patient with chronic renal failure].

A 43 year old female patient with chronic renal failure originated from polycystic kidney disease was admitted with pancytopenia. Prior to the admission, she had a history of taking allopurinol for 3 months. Allopurinol was discontinued immediately and she was treated with blood transfusion (platelet and RBC) and fluoxymesterone. The lymphocyte stimulation tests were negative for allopurinol and oxipurinol. The determination of serum levels of allopurinol and oxipurinol was disclosed to be not so high compared with other patients treated with allopurinol. On 45th day after admission, she was transfused with bone marrow from her elder brother. Thereafter bone marrow finding of the patient began to improve despite the lack of bone marrow engraftment. For further improvement, pulse treatment with corticosteroid was carried out. Although the pathophysiology of allopurinol-induced aplastic anemia remains unknown, it is interesting to note that bone marrow transfusion and pulse treatment with corticosteroid seemed effective in this case.

Adult↗

PubMed1990

Effect of serum from spontaneously hypertensive rats on 86Rb washout in cultured vascular smooth muscle cells.

In addition to the known genetic abnormalities affecting the membrane permeability of vascular smooth muscle cells (VSMC) of spontaneously hypertensive rats (SHR), serum humoral factors may also play some role in the alteration of permeability of VSMC and possibly contribute to the pathogenesis of hypertension in SHR. To test this hypothesis, the passive K permeability described as the washout rate constant (Ke) was measured based on 86Rb washout from cultured VMC in response to serum from SHR, Wistar-Kyoto rats (WKY), and Wistar rats (W). Serum from the three rat strains produced a substantial increase in the Ke of 86Rb washout from 9.6 +/- 1.7 for the control (C) of 17.3 +/- 2.0 for SHR. 15.3 +/- 0.9 for WKY, and 16.0 +/- 2.4 for W (x 10(-3)/min) (p less than 0.001 comparing C with SHR, W and p less than 0.01 comparing C with WKY respectively). However, comparison of the Ke of 86Rb washout among the three rats strains revealed no significant differences. It is concluded that serum increased passive K permeability of VSMC in culture. However, the data do not support the suggestion that some unknown humoral factors in the serum from SHR are involved in the abnormal alterations of membrane permeability to cations and thus contributing to the pathogenesis of hypertension in the SHR.

Animals↗

PubMed1989

[Uric acid metabolism in patients with chronic glomerulonephritis].

Serum uric acid (SUA), creatinine clearance (Ccr), urinary excretion of uric acid (UUAV) and uric acid clearance (CUA) were determined in 357 patients with IgA nephritis (IgAN) and 81 patients with membranous nephropathy (MGN) in an attempt to clarify uric acid metabolism in patients with chronic glomerulonephritis, and UUAV/Ccr and CUA/Ccr levels were measured to investigate their correlations. As a result, hyperuricemia that could hardly be explained with a decline of Ccr alone was recognized in many cases, since the patients with hyperuricemia exceeding 7.0 mg/100 ml of SUA registered even as high as 25.5% in IgAN and 33.3% in MGN, whereas those with the Ccr levels higher than 80 ml/min registered 22.3% in IgAN and 38.0% in MGN. Although the SUA level increased and the UUAV and CUA levels decreased along with a decline of Ccr in IgAN, no similar trends were recognized in MGN. When the distribution of UUAV was studied in the patients with the Ccr levels higher than 80 ml/min, the patients whose UUAV levels higher than 800 mg/24 hrs that suggested excessive uric acid production were markedly as low as 3.9% in IgAN and 3.7% in MGN. Thus, the cause of hyperuricemia could not be attributed to an amount in the uric acid production. On the other hand, the patients whose CUA levels lower than 6.0 ml/min in the distribution of CUA that suggested a decrease of uric acid excretion registered 47.4% in IgAN and 63.0% in MGN, respectively, which equally appeared to be a type of lowered excretion in a majority of patients whose hyperuricemia was recognized in IgAN and MGN. The mechanism of the lowered excretion of uric acids from the kidney despite the normal level of Ccr has yet to be clarified.

Adult↗

PubMed1989

[Measuring periodontal pockets with contrast media. 1. Preparation of contrast media].

Periodontal pocket is main clinical symptom of periodontitis. Measurement of periodontal pocket depth is the most important examination. The purpose of this study was to get contrast medium radiography of periodontal pocket. The present study was compared with contrast media of varying concentration. Contrast medium-sample containing 40% Sodium Iothalamate and 30% Meglumine Adipiodone had slight higher radiopacity than the others. These contrast media-sample were adequate to clinical practice over 40% concentration. Using Sodium Iothalamate and Meglumine Adipiodone, radiopacity was able to differ from radiopacity of teeth at 60%-100%.

Contrast Media↗

PubMed1989

[Induction of coronary arterial spasm by intracoronary administration of acetylcholine in patients with vasospastic angina].

To examine whether intracoronary injections of acetylcholine induce coronary artery spasm in patients with vasospastic angina, incremental doses (20, 30 and 50 micrograms) were injected directly into the coronary arteries in 12 patients with variant angina (Group A: rest angina with electrocardiographic ST-segment elevation during attacks), 19 with vasospastic angina (Group B: rest angina and/or effort angina with variable threshold in the treadmill exercise stress test), 11 with organic coronary artery stenosis but without angina (Group C), and 14 without coronary artery disease (Group D). A temporary cardiac pacemaker was positioned in the right ventricle. Coronary artery spasm was defined as severe vasoconstriction (greater than or equal to 90% of reduction in the luminal diameter) with chest pain and/or ischemic changes in the electrocardiogram. Intracoronary injection of acetylcholine induced spasm of at least one coronary artery in all 12 patients (100%) of Group A, in 18 (95%) of Group B, in two (18%) of Group C, and in two (14%) of Group D. Thus, the sensitivity of this method for inducing coronary spasm was 100% in group A, 95% in Group B, and 97% in Group A plus Group B. The specificity for inducing spasm was 86% in Group D, and 84% in Group C and Group D. When acetylcholine was injected separately into the left and right coronary arteries, spasm of both the coronary arteries was observed in two (40%) of Group A, in five (33%) of Group B, and none (0%) of Group C and Group D. Acetylcholine (20 micrograms) induced coronary spasm in 10 (83%) of Group A and only in nine (47%) of Group B.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗

PubMed1989

Malignant hypertension in three siblings.

We encountered three siblings (one female and two males) whose clinical manifestations were consistent with those of malignant hypertension (MH). Renal biopsies were obtained from two of the patients, and an autopsy from the third. The light microscopic findings from all three cases were characterised by marked intimal thickening with concentric layering of collagen and cellular proliferation in the interlobular arteries. Findings, on examination of optic fundi, including retinal haemorrhages, exudates and papilloedema were also consistent with malignant hypertension. The two male patients progressed to develop renal failure. These cases strongly suggest the existence of a rare familial form of primary malignant hypertension.

Adult↗

PubMed1988

Improvement of treadmill capacity and collateral circulation as a result of exercise with heparin pretreatment in patients with effort angina.

It has been demonstrated in animal experiments that heparin accelerates the coronary collateral development induced by repeated coronary occlusion. We used this effect of heparin for the treatment of patients with stable effort angina. In 10 patients, treadmill exercise was performed according to standard Bruce protocol twice a day for 10 days. A single intravenous dose of heparin (5000 IU) was given 10 to 20 min before each exercise period. Exercise with heparin pretreatment increased the total exercise duration from 6.3 +/- 1.9 (SD) to 9.1 +/- 2.2 min (p less than .001) and the maximal double product (DP) from 18,900 +/- 5100 to 25,500 +/- 6800 mm Hg.beats/min (p less than .001). The DP at the onset of angina was also increased by 35% (p less than .01) and the DP at which ST depression (0.1 mV) first appeared was 19% (p less than .05) greater after treatment. Repeat coronary cineangiography revealed an increase in the extent of opacification of collaterals to the jeopardized myocardium. In an additional six patients, treadmill exercise was performed with no medication twice a day for 10 days. All of the above-mentioned variables of treadmill capacity remained unchanged, despite 20 exercise periods without heparin pretreatment. Thus, heparin accelerates exercise-induced coronary collateral development by promoting angiogenesis. The development of such a therapeutic modality will open a new field for the treatment of patients with ischemia.

Angina Pectoris↗

PubMed1988

Effect of xamoterol on myocardial energetics in man.

We analyzed the effect of xamoterol (beta 1-partial agonist) on myocardial energetics in 8 patients with normal left ventricular function. We measured resting systemic and coronary hemodynamics before and after a single intravenous injection of xamoterol (0.1 mg/kg). This agent increased heart rate from 70 +/- 7 to 80 +/- 11 beats/min (p less than 0.05) and cardiac index from 2.9 +/- 0.5 to 3.2 +/- 0.5 L/min.m2 (p less than 0.01), respectively. Left ventricular peak positive dp/dt (1870 +/- 350 vs 2620 +/- 580 mmHg/sec (p less than 0.01) and left ventricular ejection fraction (62 +/- 7 vs 70 +/- 7% (p less than 0.01] also increased, while left ventricular end-diastolic pressure (9 +/- 3 vs 5 +/- 3 mmHg (p less than 0.01] and volume index (70 +/- 14 vs 58 +/- 16 ml/m2 (p less than 0.01] decreased. Coronary blood flow and total myocardial oxygen consumption did not change significantly after intervention. As a result, xamoterol enhanced left ventricular external mechanical work versus myocardial oxygen consumption ratio (mechanical efficiency) from 20 +/- 4 to 24 +/- 5% (p less than 0.01). Myocardial oxygen extraction ratio decreased significantly (p less than 0.01) from 66 +/- 5 to 62 +/- 5% after xamoterol. We conclude that xamoterol augments left ventricular mechanical efficiency accompanied by a decrease in coronary vascular tone in patients with normal cardiac function.

Adrenergic beta-Agonists↗