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Biomedical subjects

S Oguma

Publications and source records attributed to S Oguma.

At least 37 records · Page 2Linked to original sources
PubMed1992

Geographical aspects of bcl-2 gene involvement in Japanese patients with non-Hodgkin's B-cell lymphomas.

Using three separate bcl-2 probes, we examined involvement of the bcl-2 gene in Japanese patients with non-Hodgkin's B-cell lymphomas. Of 52 patients with follicular lymphoma (FL), 24 had rearrangements. In a group of 50 patients with diffuse lymphoma, three of 32 patients with diffuse large cell lymphoma had rearrangements. The frequency of rearrangements in each of these groups, as detected by both major and minor breakpoint cluster region probes, was compatible with that found in other Far Eastern studies. However, the difference in frequency between the groups studied in the Far East and the West was significant, and these two geographically distinct populations also displayed a difference in the breakpoint distribution. In the immunophenotype study of 33 patients with FL, the expression of CD10 antigen correlated with bcl-2 involvement, whereas none of the other B markers emerged as parameters to distinguish between the two lymphoma groups; those with, and without, the rearrangements.

Humans↗
PubMed1990

Simulation of dynamic changes of human T-cell leukemia virus type I carriage rates.

The human T-cell leukemia virus type I (HTLV-I) is transmitted via breast milk, semen, or blood transfusion. The last route was not responsible for HTLV-I infection before the advent of modern medicine, nor will it be a major route in the future because anti HTLV-I antibody-positive blood is now screened out. Thus, the carriage rates in various areas of Japan have to be explained by the former two transmission methods. Based on the relationship between the two modes of transmission and carriage rates, several simulation experiments were performed. These experiments revealed that: (a) No population with a vertical transmission rate lower than 50% can be maintained as endemic for the virus. (b) Slight differences in horizontal transmission rates can cause a large change of the carriage rates. (c) A 1,000-fold carriage rate difference would become indistinguishable within a hundred generations if both modes of transmission were operating at nearly the same rate. (d) The probability of a formerly non-endemic population becoming endemic due to a single female carrier is not negligible. (e) Prevention of vertical transmission is much more effective in lessening the carriage rate within a short period of time than is prevention of horizontal transmission. A simulation for a real population is also presented.

Age Factors↗
PubMed1990

[Experimental studies of transcatheter portal embolization].

The effects of transcatheter portal embolization (TPE) on energy charge (EC) and hepatic blood flow of the rat liver (HBF) were investigated. The antitumor effects on minimal tumor nodules inoculated into the rat liver via the portal vein were evaluated by the alphafetoprotein (AFP) levels and survival period after TPE. The EC of the embolized lobes was significantly decreased after TPE, as compared with the control groups, but was restored 3h later. The HBF of the embolized lobes was reduced 1h after TPE, but was restored in 1 day when TPE was performed by means of temporary embolus. When permanent embolus was used for TPE, decreased HBF persisted for at least seven days. On the other hand, HBF of the non-embolized lobes was not altered in both groups. When TPE was performed after TAE using temporary embolus, the intervals of 14 days were required for normal liver tissue to be preserved. TPE performed 3 days after inoculation of cancer cells into the rat liver caused prolongation of the survival period and decrease in the level of AFP. These results indicate that TPE does not produce marked damage to the liver and has antitumor effects on minimal tumor nodules. TAE followed by TPE may be useful for therapy of unresectable liver tumor.

Adenine Nucleotides↗
PubMed1990

[Prognostic factors in aplastic anemia. A statistical analysis of 105 cases].

We analyzed 105 cases of aplastic anemia diagnosed between 1958 and 1985 to clarify the variables that are related to prognosis. The most significant variable at diagnosis was reticulocyte count, followed in order by percent bone marrow lymphocyte, red cell turnover rate, T-score severity grade, iron utilization and aplastic anemia study group (AASG) severity grade. Reticulocyte count was the single significant variable in multivariate analysis. Three months after diagnosis, the most significant variable was still the reticulocyte count, followed by AASG severity grade. Changes of variables during the 3 months were not correlated to prognosis. Our result reconfirmed that reticulocyte count was the most important variable related to prognosis.

Adolescent↗
PubMed1989

Involvement of bcl-2 gene in Japanese follicular lymphoma.

A t(14;18) (q32;q21) chromosome translocation is closely associated with the follicular lymphoma, which is prevalent in the United States, and the t(14;18) causes the juxtaposition of a bcl-2 gene on chromosome 18 with an immunoglobulin heavy-chain gene locus on chromosome 14. Genomic DNAs from 30 Japanese patients with follicular lymphoma were examined for the molecular features by Southern blot hybridization. Using probe b for the major breakpoint cluster region of a bcl-2 gene, the rearrangements were detected in eight patients. Six of the eight patients had breakpoints located within the major breakpoint region, while two had breakpoints outside this cluster region but within the region of the 7.5-kb SstI fragment containing the probe b sequence. In two patients, pFL-2 probe detected the bcl-2 gene rearrangements that occurred near or within the minor breakpoint cluster region. These ten patients had a rearranged JH-containing fragment that migrated with the rearranged bcl-2 fragment. In the other 20 patients, these two chromosome 18-specific DNA probes did not detect the bcl-2 rearrangements. Compared with studies performed in the United States, the statistical analysis indicates a significant difference in frequency of the bcl-2 gene rearrangements near or within the major breakpoint cluster region (P = 0.0027) and the minor breakpoint cluster region (P = 0.029). However, the distribution difference of these events was not significant.

Blotting, Southern↗
PubMed1989

A histometric analysis of chronically rejected human liver allografts: insights into the mechanisms of bile duct loss: direct immunologic and ischemic factors.

Conspicuous pathologic features of chronic liver allograft rejection include bile duct loss and chronic obliterative arteriopathy. A quantitative histometric analysis was performed to document the extent of bile duct loss, the size of the "vanished" ducts and the extent of chronic obliterative arteriopathy and to determine whether there was any relationship between chronic obliterative arteriopathy and bile duct loss. All failed liver allograft specimens with chronic rejection were reviewed and categorized according to the degree of chronic obliterative arteriopathy, assessed by the degree of luminal narrowing of hilar hepatic artery branches. Histometric analysis of the grafts revealed: (i) there was a loss of small portal arterioles (less than 35 microns); (ii) bile ducts which should accompany arteries less than 35, 35 to 54 or 55 to 74 microns in diameter were missing, with the greatest decrease occurring among the smallest ducts; (iii) bile duct loss was seen in the absence of significant large vessel chronic obliterative arteriopathy, and (iv) the severity of arteriole and bile duct loss, as well as the size of the vanished ducts, was directly proportional to the degree of chronic obliterative arteriopathy. Furthermore, the size of the "vanished" bile ducts in liver allografts appeared to differ from the size of ducts destroyed in primary biliary cirrhosis. These studies offer indirect, but suggestive proof that two mechanisms are operative in the bile duct loss seen in chronic rejection: direct lymphocytotoxicity and ischemic damage.

Adolescent↗
PubMed1989

Adult T cell leukemia: a case with massive hyperimmunoglobulinemia E.

Adult T cell leukemia, an endemic disease in the southwestern part of Japan, is characterized (1) by a short survival, (2) by leukemic T cells in peripheral blood that have lobulated nuclei and helper/inducer surface phenotypes, and (3) by cutaneous involvement. A 34-year-old man who had a history of atopic dermatitis was seen at our clinic because of generalized erythroderma and lymphadenopathy. His clinical course was rather chronic as compared with that of prototypic adult T cell leukemia; however, typical leukemia cells were observed in specimens taken from his peripheral blood and skin. The diagnosis of adult T cell leukemia was established by the patient's positive serum antibody reaction to adult T cell leukemia-associated antigen and monoclonal integration of virus genome in the patient's leukemia cell DNA. Interesting and characteristic of the patient were the very high levels of serum immunoglobulin E. With the use of an in vitro immunoglobulin production system with mitogen, the patient's T lymphocytes enhanced the differentiation of B cells, both from the patient and from a normal adult, into immunoglobulin E-producing cells. Therefore it may be speculated that T cells functioning as immunoglobulin E-specific helpers were transformed to leukemia cells by human T-lymphotropic virus type I. Continuous antigen stimulation of the patient's atopic diathesis also may be a factor.

Adult↗
PubMed1989

The UW solution for canine kidney preservation. Its specific effect on renal hemodynamics and microvasculature.

The preservation effects of UW solution on renal hemodynamics and microvascular systems were studied in canine kidney autografts. In 72-hr UW-preserved kidneys, the microvessels of both cortex and medulla were completely visualized with silicon rubber compound 1 hr after reperfusion. Histology also showed extremely well-preserved arterioglomerular and tubular systems. These results were correlated with good renal blood flow, prompt recovery of posttransplant graft function, and 100% two-week survival of dogs. In contrast, kidneys preserved for 72 hr with Euro-Collins solution showed necrotic and obstructive changes of the microvasculature and deterioration of renal hemodynamics. In 120-hr UW-preserved kidneys, the microcirculation of the medullary region became poor after reflow when there was fairly intact perfusion of the cortical region, indicating an ischemia-related intrarenal blood flow maldistribution. The 120-hr kidneys subsequently failed in spite of having a good blood flow and morphologically well-maintained microvasculature after reperfusion. These data demonstrated that much, but not all, of the beneficial effect of UW solution in kidney preservation might be attributed to its remarkable protection of renal microvasculature. Correction of intrarenal blood maldistribution caused by a discrepancy in tolerance to ischemia of the vascular and tubular systems might be important in successfully preserving the kidney for 120 hr.

Adenosine↗
PubMed1989

Prognosis of refractory anemias.

Several aspects of prognosis of myelodysplastic syndromes were reviewed with special attention to refractory anemia (RA). The median survivals were 14 months in chronic myelomonocytic leukemia, 16 months in RAEB, 42 months in RA, and 58 months in RA with ring sideroblasts (RARS). Cumulative leukemia-free rates at 5 years were 31% in RAEB, 80% in RA, and 92% in RARS. The proportion of cases having very low hazards for leukemic transformation or for nonleukemic death was 92% (RARS), 73% (RA), and 26% (RAEB) for leukemic transformation and 23% (RA) and 29% (RAEB) for nonleukemic death. All RARS cases had hazard for nonleukemic death. In RA, the annual mortality rate was about 5 to 11 times higher than that of age-and sex- matched general population up to 6 years. After which no failure was found in RA cases with survival rate of 33% up to 14 years. The relative importance of hazard from leukemic transformation to nonleukemic death in RA was about one half at presentation, but this declined to less than 10% after 10 years.

Anemia, Refractory↗