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Biomedical subjects

S Oguma

Publications and source records attributed to S Oguma.

At least 55 records · Page 3Linked to original sources
PubMed1989

[Preleukemic disorders].

Certain hematopoietic disorders and immunodeficiency states are known to carry a risk of developing acute nonlymphocytic leukemia. In the past some of them have been classified by a variety of terms ranging from refractory anemia to preleukemia, but are currently grouped into a new concept of the myelodysplastic syndromes (MDS). The purpose of this article is to briefly review the updated knowledge of the MDS with emphasis on the clonal origin, natural history and mechanisms of leukemogenesis.

Cell Transformation, Neoplastic↗
PubMed1989

S100 protein positive dendritic cells in primary biliary cirrhosis and other chronic inflammatory liver diseases. Relevance to pathogenesis?

A study to determine the location of dendritic cells, in chronic inflammatory liver disease was performed. S100 protein positivity and dendritic cytoplasmic morphology were used to identify dendritic cells. S100 protein positive dendritic cells (S100 + DC) were found inside the basement membrane between biliary epithelial cells of septal bile ducts of livers affected by early stage PBC, but were not present at later stages. S100 + DC also were seen in areas of piecemeal necrosis in chronic active hepatitis of various etiologies. In contrast, intra-epithelial S100 + DC were not found with any consistency in sclerosing cholangitis, secondary biliary cirrhosis, extrahepatic biliary atresia, or chronic liver allograft rejection, all of which are characterized by inflammatory bile duct damage. The possible relevance of DC in the pathogenesis of PBC is discussed.

Dendritic Cells↗
PubMed1988

Participation of dendritic cells in vascular lesions of chronic rejection of human allografts.

Immunohistochemical techniques were used to investigate the pathogenesis of obliterative arteriopathy, a major obstacle to long-term solid organ allograft survival. T-lymphocytes, macrophages, and proliferating smooth muscle cells made up most of the thickened intima. More importantly, S100-protein-positive dendritic cells were also present in the intima, especially during active inflammation and smooth muscle cell proliferation. These are phenotypic characteristics of tissue "dendritic" cells, pivotal accessory cells in T-dependent immune reactions. Their localisation in the arterial wall signals the presence of an ongoing immunological reaction directed at native constituents of the artery or at exogenous antigens which permeate the damaged vessel wall.

Arterial Occlusive Diseases↗
PubMed1988

A histometrical study on the development of three glomerulopathies.

A histometrical study of the distribution pattern of hyalinized glomeruli in diabetic glomerulosclerosis, malignant nephrosclerosis and chronic glomerulonephritis was achieved using the nearest neighbor method. The features of the circulatory dynamics in each disease are discussed based on the results of this study. The glomeruli were hyalinized at random in diabetic glomerulosclerosis. The distribution of hyalinized glomeruli occurred at random in normal kidney, which suggests that glomeruli become hyalinized with no dependency on the vasculature. Malignant nephrosclerosis on the other hand, shows that the glomeruli are hyalinized in clusters, and that suggests that the kidneys react to hypertensive changes in the interlobular artery and more peripheral arteries. The glomeruli supplied by the interlobular arteries will then hyalinize in clusters. If these two renal diseases are used as an end of a spectrum, the distribution pattern of hyalinized glomeruli in chronic glomerulonephritis showed most similarity with that seen in malignant nephrosclerosis. However, the percentage of hyalinized glomeruli was 21% in malignant nephrosclerosis as opposed to 77% in chronic glomerulonephritis. This marked difference suggests that in malignant nephrosclerosis, the percentage of hyalinized glomeruli was low due to participation of arteries larger than the accurate branches. However, the patients became uremic within a short time. Contrary to this finding, in chronic glomerulonephritis, the effect is from the smaller arteries less than that from the interlobular artery. Ordinarily, if an insufficient number of glomeruli become hyalinized, uremia will not develop. Finally, the difference in the genesis and vascular participation of diffuse type and nodular type of diabetic glomerulosclerosis and the relationship between acute glomerulonephritis and chronic glomerulonephritis are discussed.

Adolescent↗
PubMed1988

Refractory myelodysplastic anaemias with hypocellular bone marrow.

Thirty three patients with refractory myelodysplastic anaemias (RMDA) with marrow hypocellularity were reviewed to see whether they differed from those with normocellular or hypercellular marrows. The median age was 65 years with a male:female ratio of 26:7. There were 11 cases of refractory anaemia (RA), four of refractory anaemia with ringed sideroblasts (RARS), and 18 of refractory anaemia with excess of blasts (RAEB). All presented with peripheral cytopenias, mostly pancytopenia or bicytopenia dysplasia in one or more cell lineages, and a marrow biopsy specimen with less than normal numbers of nucleated cells for the age. Twenty four patients died, including 14 of the 16 who developed acute non-lymphocytic leukaemia (ANLL). The results suggest that patients with hypocellular RMDA have a similar prognosis to those with normocellular or hypercellular marrows at presentation.

Adult↗
PubMed1987

Factors influencing nonleukemic death in refractory anemia, refractory anemia with ring sideroblasts, and refractory anemia with excess of blasts.

The association between nonleukemic death and various features recorded at presentation in patients with refractory anemia (RA), RA with ring sideroblasts, and RA with excess of blasts was analyzed in 251 patients using the proportional hazards model. Features associated with higher nonleukemic death rates were: 1% or more metamyelocytes in peripheral blood (PB); lower 59Fe incorporation rate; 1% or more blasts in PB; lower hematocrit or hemoglobin; presence of giant platelets; 1 microgram/liter or higher serum vitamin B12 levels; higher periodic acid-Schiff positive erythroblasts; and 1% or higher promyelocytes in PB. Multivariate analysis was also performed using the following predictor variables: metamyelocytes in PB, micromegakaryocytes, hemoglobin, giant platelets, presence or absence of RA with excess of blasts, and mononuclear large megakaryocytes. Patients were divided arbitrarily into low (hazard ratio, less than 0.55), intermediate (hazard ratio, 0.55-1.5), and high (hazard ratio, greater than 1.5) risk groups. The cumulative nonleukemic death rates in the high and intermediate risk groups reached a median at 602 and 1984 days from presentation, respectively, while the rate reached a plateau level of 49.4% after 2644 days in the low risk group. The risk factors for leukemic transformation and nonleukemic death were found to be different and to need separate consideration.

Anemia, Refractory↗
PubMed1987

Varying probability of the development of acute nonlymphoblastic leukemia in refractory anemia patients with an excess of blasts.

The cumulative leukemia-free survival rate of refractory anemia with excess of blasts was fitted to three parametric failure time models, i.e., the usual exponential and Weibull, and exponential mixture models. Among the three, the best fit model was the exponential mixture model, which was 119 times more likely to assume that samples came from the exponential mixture distribution than to assume that those were from the usual Weibull distribution. This strongly suggests that refractory anemia with excess of blasts consists of subgroups with very high and very low probability to develop acute nonlymphoblastic leukemia. The estimated proportion of the very low probability group was about 30%. Analysis by the exponential mixture model with covariates revealed that the probability of a patient to develop acute nonlymphoblastic leukemia could be estimated by three covariates, i.e., bone marrow blast percentage; abnormal granules of granulocytes; and mononuclear large megakaryocytes. The estimated probabilities ranged from 17 to 99%, according to the model.

Acute Disease↗
PubMed1987

Effects of superselective arterial embolization and chemoembolization on energy charge and total blood flow of the rat liver.

The superselective transcatheter arterial embolization (TAE) and chemoembolization (TAC) of the periphery of the left and median lobes of the rat liver were performed using 1.5 mg of gelatin sponge dissolved in saline solution and mitomycin (MMC) at a dose of 1.6 mg/kg b.wt. The energy charge (EC) of the embolized and chemoembolized lobes decreased after the embolization but was restored 3 h later. The total hepatic blood flow (THBF) was reduced to about one half and required 1 week to be restored to the preembolization levels in both groups. Microscopic centrilobular necrosis and vacuolization were found. The addition of MMC did not produce marked untoward effects. Thus, the normal liver is able to restore its energy pool despite a reduction in the THBF after superselective arterial embolization, and this recovery is not altered even by the use of a high dose of MMC.

Adenine Nucleotides↗
PubMed1987

[FT, 5-FU and uracil concentrations of the blood, bile and tissue of hepatoma with liver cirrhosis after oral administration of UFT].

UFT was orally administered to eight patients with hepatocellular carcinoma (HCC) combined with liver cirrhosis and to five patients with normal liver. The concentrations of FT-207 (FT), 5-FU, and uracil in blood, tissue and bile were then respectively determined. The FT level in cancer tissue and non-cancer tissue was almost identical in patients with HCC. On the other hand, the 5-FU level in normal liver tissue was significantly higher (P less than 0.05) than that in cancer tissue, and the uracil level in normal liver tissue was lower than that in cancer tissue (P less than 0.05). Transportation of FT from blood to liver was significantly correlated with clearance of indocyanine green from the blood (ICGK). These results suggested that transportation of FT from blood to liver and activation of FT were impaired in HCC with liver cirrhosis. However, the 5-FU level in the cancer tissue of HCC tended to be higher than that in non-cancer tissue. The 5-FU level in the tissue had a significant correlation with the FT level in the tissue. In addition, it was presumed that cancer tissue was able to produce 5-FU from FT more quickly than non-cancer tissue.

Administration, Oral↗
PubMed1987

[Pancreatic duct treatment in pancreas transplantation].

To determine the utility of injection of polymers to obliterate the pancreatic duct, we examined this method and others viz, pancreatico-duodenostomy, duct ligation, and the open duct method. We performed the pancreatic duct treatment on the left portion of the pancreas in dogs without any transplantation. The right portion of the pancreas was removed. We used Neoprene and Ethibloc as injected materials. One month after the operation, the polymer injected dogs showed the same endocrine function as the duct ligated and open duct ones. However, three months after the operation, endocrine function of the polymer injected dogs improved and was better than that of the other two groups which showed no changes. The endocrine function of the polymer injected dogs had remained stable for one year and was close to that of the optimal function of pancreatico-duodenostomy. Furthermore, after operation in the polymer injected dogs, the elevated serum amylase descended to normal level. This occurred much less rapidly in the other groups. The fibrosis of the polymer injected dogs' pancreas was completed by 3 months, while the dogs in the other groups still had some degenerated exocrine tissues. Rapid destruction of exocrine tissues, induced by the injection of the polymer, appears to encourage reconstruction of endocrine tissue.

Animals↗
PubMed1987

Useful antiglobulin crossmatch test for DST-sensitized patients.

The AG-CDC tests were performed in parallel with C-CDC tests for studying sensitization of DST patients. Fourteen of 56 DST patients were positive by the AG-CDC tests after DST. Ten of 14 were also positive by both tests after DST. In 8 of 14 patients AG-CDC antibodies continued to be detectable even after C-CDC antibodies became undetectable as time passed and with plasmapheresis. Thus, AG-CDC tests are more sensitive compared to C-CDC tests and can extend the detection rate of DST-sensitized patients. Except for two DST patients (highly sensitized), 12 of 14 DST-sensitized patients were given transplants from specific blood donors at the time when their C-CDC tests became negative. One graft failed, another one had impaired function, and ten of them functioned. It should be noted that DST patients were transplanted successfully with or without plasmapheresis across a positive AG-CDC test if the titer was less than 1:4 at the time of transplant. All four DST recipients who developed antibodies detected only by AG-CDC tests after DST experienced severe accelerated rejections. In contrast, two of eight patients who were positive by both tests had "severe" accelerated rejections. The incidence of severe accelerated rejections was shown to be highly associated with the presence of AG-CDC antibodies. These facts suggest that AG-CDC antibodies may damage kidney grafts and result in severe accelerated rejections; and that AG-CDC tests are useful for predicting occurrence of severe accelerated rejections in DST recipients.

Blood Transfusion↗