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Biomedical subjects

Y Oh

Publications and source records attributed to Y Oh.

178 records · Page 10Linked to original sources
PubMed1987

Cerebral hemorrhage in patients on maintenance hemodialysis. CT analysis of 25 cases.

Site of hematoma and clinical outcome in cerebral hemorrhage were analyzed in 25 maintenance hemodialysis (HD) patients and compared with those in 27 non-HD patients. Ganglionic-thalamic hemorrhage was found in 56% of HD and 74% of non-HD patients, lobar hemorrhage in 36% and 11%, respectively. Size of hematoma, expressed as a ratio (%) of hematoma area to entire brain on CT slice, was 6.5 +/- 4.2% (mean +/- SD) in HD, being significantly larger than that of 4.7 +/- 3.5% in non-HD patients (p less than 0.05). Mortality rate was 60% in HD patients, nearly twice as much as the 33% in non-HD patients. The hematomas were significantly larger in the death cases (8.4 +/- 3.7%) than the survivors on HD (3.6 +/- 3.1%, p less than 0.005). Likewise, the fatal cases in the non-HD group had bigger hematomas (6.9 +/- 4.3%) than the non-fatal ones (3.6 +/- 2.4%, p less than 0.05). Intraventricular hemorrhage (IVH) was found in 40% of HD and 44% of non-HD patients. Hematomas were significantly larger in HD patients with IVH (9.3 +/- 3.3%) than in those without IVH (4.6 +/- 3.7, p less than 0.005). Ninety percent of the HD patients with IVH but only 42% of non-HD patients died of hemorrhage. Hypertension was equally seen in HD (76%) and non-HD patients (74%). It is concluded that in HD patients cerebral hemorrhage is more severe in terms of hematoma size, association of IVH and clinical outcome. Chronic systemic heparinization might be responsible to the severity in HD patients.

Adult↗
PubMed1987

Effects of acute reduction in blood pressure on the renal function of rats with diseased kidneys.

We studied the effect of an acute reduction in blood pressure, induced by diltiazem, on the renal hemodynamics of spontaneously hypertensive rats (SHR) with focal glomerular sclerosis, as induced by adriamycin (ADR). Renal plasma flow (RPF) and glomerular filtration rate (GRF) were determined before (first period) and during (second period) intravenous infusion of diltiazem in SHR 4-6 weeks after ADR treatment (group 1), 14-20 weeks after treatment (group 2), and in controls without treatment (group 3). Rats in group 1 had a normal renal function (RPF and GFR) in the first period, which was not significantly different from control rats (group 3). Rats in group 2 showed a reduced renal function, reflected by the lower levels of RPF and GFR, compared with groups 1 and 3. Mean blood pressure decreased equally in the 3 groups by about 50 mm Hg after the infusion of diltiazem. During the second period, 13.4 or 12.4% increase in RPF and a 29.0 or 23.2% elevation of GFR were evident in groups 1 or 3, respectively. In contrast, a 32.0% reduction of RPF was observed in group 2, accompanied by a 25.7% decline of GFR. A reduction in renal function (percent change of RPF or GFR) significantly correlated with the severity of renal dysfunction (RPF or GFR in the first period) in group 2. Thus, the renal function of rats with diseased kidneys is sensitive to an acute reduction in blood pressure by diltiazem, and the sensitivity depends on the degree of renal deterioration.

Animals↗
PubMed1986

Adriamycin-induced nephropathy as a model of chronic progressive glomerular disease.

Serial changes in urine protein, blood chemistry, and histology of the kidney were investigated in rats for 28 weeks after injections of adriamycin (ADR). Massive proteinuria, hypoalbuminemia, and hyperlipidemia were observed at week 4 and throughout the experiment. Both BUN and serum creatinine began to increase at week 16 and reached the uremic level at week 28. Light microscopic study of the kidney demonstrated a normal appearance at week 4, vacuole formation in glomerular tuft at weeks 8 and 12, focal and segmental glomerular sclerosis at weeks 16 and 20, and extensive glomerular sclerosis with tubulointerstitial degenerations at weeks 24 and 28. Immunohistologically, IgM with a small amount of IgG and C3 appeared in the sclerosing glomeruli from week 16. Aggregated human IgG, injected intravenously at week 24, had accumulated mainly in the glomeruli. Electron microscopy revealed degenerative changes of glomerular epithelial cells with small vacuoles in the cytoplasm at week 4. Size of vacuoles increased at the later stage. In conclusion, ADR produced chronic, progressive glomerular changes in rats, which led to terminal renal failure. The segmental glomerular sclerosis and IgM-dominant glomerular deposition in these animals are similar to pathological characteristics of focal and segmental glomerular sclerosis seen clinically.

Animals↗
PubMed1986

Effect of hypertension on the progress and prognosis of experimental focal glomerular sclerosis.

Effect of hypertension on progressive renal disease was examined in spontaneously hypertensive rats (SHR) with experimental focal glomerular sclerosis, produced by the intravenous administration of adriamycin (ADR). Serial changes of urinary protein, blood pressure and blood chemistry for 22 weeks after ADR-treatment, and renal histology at week 22, were compared between ADR-treated SHR (group ADR-HT) and ADR-treated SHR given antihypertensive drugs (group ADR-AH). Hypertension persisted in group ADR-HT, while blood pressure markedly decreased in group ADR-AH, after oral administration of antihypertensive drugs (guanethidine and hydralazine). Massive proteinuria, hypoalbuminaemia and hypercholesterolaemia were observed throughout the experiment both in group ADR-HT and in group ADR-AH. Urinary protein levels were significantly larger in the former at weeks 12 and 16. Blood urea nitrogen and serum creatinine levels increased progressively from week 16 in the ADR-treated rats. The increase was more rapid in group ADR-HT than in group ADR-AH. In group ADR-HT, 10 of 25 rats died between weeks 20 and 22, whereas all in group ADR-AH survived. Histologically, ADR-treated rats showed focal glomerular sclerosis with tubulointerstitial changes. The lesions were more extensive in group ADR-HT than in group ADR-AH. We conclude that hypertension influences the progress and prognosis of chronic progressive renal disease, as induced by adriamycin.

Animals↗
PubMed1986

Glomerulocystic kidneys. Report of an adult case.

Glomerulocystic kidney characterized by dilatation of Bowman's space occurs primarily in infants and children. We treated a normally developed 29-year-old Japanese man for hypertension and renal failure, who had been well up to 6 months before admission. Extrarenal malformations were not determined. A biopsy of both kidneys was done at the time of interdialysis, and the histology revealed diffuse glomerular cystic lesions. Electron-dense deposits were also observed in the mesangial area. Radiological studies of the kidneys showed numerous minute cysts in the cortical area, a normal architecture of the arterial trees, and negative evidence of urinary tract obstruction. This may be the first documentation of glomerulocystic kidney in an adult, without extrarenal anomalies.

Adult↗
PubMed1986

Immune alterations in hemodialyzed patients. I. Effect of blood transfusion on T-lymphocyte subpopulations in hemodialyzed patients.

The immune status in 42 patients with end-stage renal failure on maintenance hemodialysis was studied by using monoclonal antibodies to lymphocyte subpopulations. Lymphopenia, reductions in the proportion of OKT4+ cells and OKT4+/OKT8+ cell ratio were observed in hemodialyzed patients. These alterations in immune status were observed in 34 transfused patients, but not in 8 patients without history of blood transfusion. The proportion of OKT8+ cells was increased in patients with history of blood transfusion. When transfused patients were divided according to the dose of blood transfused in the last 2 yr, the most serious change was observed in those who received greater than 10 u of transfusion. The dose of blood transfused in the last 2 yr correlated positively with the proportion of OKT8+ cells (p less than 0.01) and inversely with OKT4+/OKT8+ cell ratio (p less than 0.05). The duration of hemodialysis did not affect the alterations in immunoregulatory cells. These results indicate that alterations in immune features in hemodialyzed patients may be linked to the history of blood transfusion rather than that of uremia and/or hemodialysis.

Adolescent↗
PubMed1986

Effect of blood pressure on the progress of renal deterioration in rats with renal mass reduction.

The effect of hypertension on the progress of renal deterioration with renal mass reduction was investigated in spontaneously hypertensive rats. Nephrectomies of five sixths, two thirds, and one third were performed. The antihypertensives guanethidine and hydralazine were given to half of the rats. Increase in urinary protein excretion and decreases in serum total protein and albumin were greater in rats with a larger nephrectomy. With the same extent of nephrectomy, these changes were severe in the group of rats with untreated hypertension, as compared with findings in rats given the antihypertensive drugs (AHD). Similar changes were obtained in BUN and creatinine levels. Only the animals with a five-sixths nephrectomy and hypertension became uremic. Glomerulosclerosis in five-sixths nephrectomized rats with hypertension was present in 71% of the glomeruli, whereas it was reduced to 34% in rats treated with AHD. The diameter of normal-appearing glomeruli increased significantly in rats with a large nephrectomy, but did not differ between the groups given or not given AHD. Medical thickening of the arterial walls, which increased with the reduction of renal mass, was significantly greater in five-sixths nephrectomized rats with hypertension than in those treated with AHD. These results indicate that a hyperdynamic state of the glomeruli, that is, a prominent urinary protein excretion and compensatory glomerular hypertrophy, may play a causative role in the progress of glomerulosclerosis in rats with extreme renal mass reduction. The hypertensive state may aggravate these renal dysfunctions.

Animals↗
PubMed1985

Rapidly progressive renal deterioration in partially nephrectomized rats with experimental membranous nephropathy.

The effects of nephron loss on the clinical and histological picture of experimental membranous nephropathy were examined for 18 weeks in five-sixths nephrectomized rats with Heymann nephritis (HN-5/6N group). Heymann nephritis-induced rats without nephrectomy (HN group), normal rats with 5/6 nephrectomy (5/6N group) and normal rats without nephrectomy (control group) were also examined for comparison. A rapidly progressive increase in urinary protein, BUN and serum creatinine was observed after renal ablation in the HN-5/6N group. Light microscopic study revealed global or segmental sclerosis in most of the glomeruli, crescent formation in some of the glomeruli and marked tubulointerstitial changes. Electron microscopic study demonstrated vacuolation and necrosis of podocytes, detachment of podocytes from the glomerular basement membrane (GBM) and fibrin exudation into Bowman's space. Proteinuria was also marked but renal function was not impaired in the HN group. In the 5/6N group, proteinuria was mild and elevation in BUN and serum creatinine was apparent but not progressive. There were no differences in the depositions of IgG, C3 and electron-dense materials on GBM between the HN-5/6N group and the HN group. In conclusion, renal mass reduction associated with high flow and pressure to the remnant glomeruli could lead to extensive glomerular sclerosis and to a deterioration in renal function, in the case of pre-existing nephritic lesions.

Animals↗
PubMed1985

Chlorocardicin, a monocyclic beta-lactam from a Streptomyces sp. I. Discovery, production and biological activities.

Chlorocardicin is a new monocyclic beta-lactam produced by a Streptomyces sp. It is structurally related to nocardicin A but differs in having a m-chloro substituent on the p-hydroxyphenylglycine unit. The biological activity of chlorocardicin was similar to nocardicin A but the former showed less antagonism in complex media. Moderate in vitro activity was observed against Enterobacteriaceae and Pseudomonas aeruginosa. Chlorocardicin showed low activity against Staphylococcus aureus whereas nocardicin A was inactive. Both compounds were shown to be strongly potentiated by antibiotics that inhibit peptidoglycan biosynthesis and were antagonized by selected L- and D-amino acids.

Anti-Bacterial Agents↗
PubMed1984

Renal amyloidosis associated with crescentic glomerulonephritis.

A case of renal amyloidosis coincidentally associated with crescentic glomerulonephritis is described. A 59-year-old female with 30 years' history of rheumatoid arthritis developed nephrotic syndrome followed by rapid deterioration of renal function. Among 28 glomeruli in a kidney biopsy specimen, glomerular amyloid deposition was present in 17 and crescent formation in 20. Only one glomerulus was free from amyloid deposition or crescent. The amyloid deposition was clearly demonstrated by congo red, thioflavin-T staining as well as electron-microscopic examination. Glomerular deposition of immunoglobulins and/or complements were not noted. While cyclophosphamide, dipyridamole, and heparin followed by pulse methylprednisolone were given, the renal function deteriorated progressively and dialysis was initiated. Renal function, however, recovered partially without medication after peritoneal dialysis of 3 months' duration. The second renal biopsy revealed the progression of glomerular amyloid deposition and the increase in fibrous component of crescent.

Amyloidosis↗
PubMed1984

Autologous immune complex nephritis in streptozotocin-induced diabetic rats.

In order to investigate the influence of diabetes mellitus on immune complex-mediated nephritis , we produced Heymann nephritis in streptozotocin-induced diabetic rats (DM-HN group) in which the clinical course for 24 weeks and histological changes were examined. Nondiabetic rats with Heymann nephritis (HN group) and diabetic rats (DM group) were also examined as controls. The degree of proteinuria, hypoproteinemia, hyperlipidemia and anemia were more pronounced and the mortality rate was higher in the DM-HN group than in the HN group or in the DM group. Histologically, larger and more subepithelial or intramembranous electron-dense deposits as well as a more markedly thickened glomerular basement membrane (GBM) were observed in the DM-HN group than in the HN group. In conclusion, the nephrotic manifestations and histological changes in the GBM in Heymann nephritis were augmented by the association with diabetes mellitus.

Animals↗
PubMed1984

Necrotizing vascular lesions in spontaneously hypertensive rats with nephrotic syndrome: hypercoagulability as a contributory factor.

Heymann nephritis was induced in rats with spontaneous hypertension (group HN), and renal lesions were investigated at the twentieth and thirty-sixth week. An identical group given antihypertensive drugs (group HN-AH), an identical group given anticoagulant drugs (group HN-AC), and a nonimmunized control group of spontaneously hypertensive rats (controls) were also examined. Massive proteinuria, hypoalbuminemia, and hyperlipidemia were present in groups with induced Heymann nephritis (HN, HN-AH, and HN-AC). Coagulation studies demonstrated a shortening of prothrombin time, an increase in serum fibrinogen and thrombocytes, and a reduction of antithrombin III in the groups HN and HN-AH. Necrotizing lesions were observed only in group HN and without further elevation in blood pressure. Intravascular thrombosis was prominent at the twentieth week, and marked fibrinoid necrosis appeared at the thirty-sixth week. These vascular lesions were not observed in the HN-AH, HN-AC, and control groups. Thus, a state of hypercoagulability in addition to high blood pressure probably contributes to the genesis of necrotizing vascular lesions in spontaneously hypertensive rats with nephritis.

Animals↗
PubMed1983

Influence of hypertension on the progression of experimental autologous immune complex nephritis.

In order to determine the influence of hypertension on the progression of chronic glomerulonephritis, we studied the renal lesions in Heymann nephritis (autologous immune complex nephritis) produced in SHR. Nephritic SHR treated by AHD, normal SHR, nephritic WKYR, and normal WKYR served as controls. Induction of Heymann nephritis did not alter the blood pressure in either SHR or WKYR as compared with each untreated control group. Administration of AHD normalized the blood pressure of SHR. Proteinuria, hypoproteinemia, hypercholesterolemia, and reduction in body weight were significantly greater in nephritic SHR than in nephritic SHR treated by AHD or nephritic WKYR, whereas BUN and serum creatinine were unchanged in all the nephritic rats. Histological findings such as glomerular basement membrane thickening, IgG and C3 deposits along capillary walls, and subepithelial electron-dense deposits were similar in all nephritic groups. Glomerular sclerosis and tubulointerstitial changes were more marked in nephritic SHR than in the other nephritic groups. Severe vascular thickening and necrosis, intravascular thrombosis, and perivascular cell infiltration were frequently observed in nephritic SHR. These lesions are characteristic of malignant hypertension. However, they were not found in control SHR, which maintained elevation of blood pressure equivalent to that of nephritic SHR throughout the study. It was concluded that hypertension may aggravate nephritic manifestations such as proteinuria, hypoproteinemia, and hypercholesterolemia but not excretory renal function and that the hypertensive vascular lesions are augmented by Heymann nephritis.

Animals↗
PubMed1977

Significant structure theory applied to liquid helium-3.

The significant structure theory of liquids is successfully applied to the quantum liquid (3)He. The partition function uses the Debye partition function for the solid-like molecules and the Fermi-Dirac partition function for the gas-like degrees of freedom. To evaluate the gas-like partition function, numerical calculations are performed and some integral functions appearing in the equation of state of the ideal Fermi-Dirac gas are tabulated. In the solid-like molecules, the molar volume V(s) depends on the temperature, and a linear dependence is used.The thermodynamic properties, such as molar volume, vapor pressure, entropy, heat capacity, and the critical constants as well as the surface tension of liquid (3)He are calculated. The agreement between theory and experiment is satisfactory.

Journal Article↗