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Biomedical subjects

S Sakamoto

Publications and source records attributed to S Sakamoto.

At least 541 records · Page 30Linked to original sources
PubMed1989

[Immunoelectron microscopic observation of membranous nephropathy in children using protein A-gold complex method].

The ultrastructural localization of immunoglobulins (IgG, IgA, IgM), complement component (C3c), or fibrinogen-related antigen (FRA) was investigated on 5 biopsy samples from 5 children with idiopathic MN or lupus nephritis using protein A-gold (PAG) complex method. The immunoreactivity of IgG was essentially confined to the mesangial and subepithelial electron-dense deposit (EDD) in all of 5 children, and more intense staining of IgG was observed in 3 children with stage II of MN than those with stage I and stage III of MN. Double immunocytochemical staining showed the same distribution of both IgG and IgM or both IgG and FRA in subepithelial EDD in 2 of 5 children. These findings suggest that IgG deposits are associated with the formation of subepithelial EDD in MN, and raise the possibility that IgM and FRA deposits may result from entrapment and/or immunological reaction.

Adolescent↗
PubMed1989

[Aclarubicin-combined combination chemotherapy in patients with refractory or relapsed non-Hodgkin's lymphoma].

Patients with lymphoma who became refractory or resistant to standard chemotherapy including anthracyclines were treated with aclarubicin-combined chemotherapy including VP-16, ifosfamide, and carboquone in a multicenter study. Twenty-one patients were entered in this study, and 18 of them were evaluable. The median age was 52 years old (range 27-74), and there were 17 male and 3 female patients. The vast majority of patients were diagnosed as having diffuse lymphoma, of which 10 cases had large cell type. Surface markers were measured in 8 patients, of whom 4 had T-cell lymphoma. Remission was attained in 3 of 18 patients (17%) with one complete and lasting remission with T-cell lymphoma. In conclusion, the response rate in this study was poor, but this type of combination chemotherapy might be considered in patients with T-cell lymphoma.

Aclarubicin↗
PubMed1989

A transient hemolytic reaction and stomatocytosis following vinca alkaloid administration.

We analyzed hemolytic reaction following vinca alkaloid administration in patients with acute lymphoblastic leukemia, blast crisis of chronic myelogenous leukemia and malignant lymphoma in the leukemic phase. During the course of chemotherapy in which vinca alkaloids were included, indirect-form dominant hyperbilirubinemia was observed in 21 of the 31 evaluable patients. In 8 patients with hyperbilirubinemia, reticulocytosis coincided with vinca alkaloid administration. Peripheral blood films showed prominent anisocytosis in 4 patients and increased stomatocytes in 10 patients. Red cell membrane studies in patients with hemolysis revealed increased sodium transport and increased activity of Na+, K+-ATPase. These findings were considered to represent the abnormal membrane "leakiness". Thus, vinca alkaloids might induce erythrocytotoxicity, which leads to acquired stomatocytosis with hemolysis in some patients.

Adult↗
PubMed1989

[Two cases of anorectal malignant melanoma].

Although on anorectal malignant melanoma is relatively rare, we report two cases, that of a 88-year-old woman, and a 78-year-old man. Both patients were admitted to the hospital due to rectal bleeding and were diagnosed as having rectal carcinoma. Following an abdominoperineal rectal amputation, a pathological examination of the resected specimens revealed a malignant melanoma. Thus, it is necessary to carry out a careful examination of patients with tumors of the anorectal region when there is the least suspicion of a malignancy.

Aged↗
PubMed1989

Transformed malignant lymphoma from Lennert's lesion is a CD4+ T cell lymphoma: an immunohistochemical study.

We describe a case of Lennert's lesion terminating in T cell non-Hodgkin's lymphoma (NHL). A 53-year-old woman showed inguinal lymphadenopathy. This was histologically interpreted as toxoplasmic lymphadenitis. However, Lennert's lesion was diagnosed in subsequent biopsies. Because additional lymphadenopathy and constitutional symptoms were absent, anti-neoplastic therapy was not given. During the five and a half years after the initial biopsy, generalized lymphadenopathy and constitutional symptoms developed. Histological examination of the cervical lymph node disclosed NHL, diffuse, large cell type. Transformed lymphoma cells were confirmed to be of peripheral T cell origin with a helper/inducer phenotype. We speculate that some cases of Lennert's lesion have a potentiality of spontaneous transformation into high grade malignant lymphoma associated with disappearance of epithelioid histiocytes.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1989

[A case report of biventricular assistance by means of ventricular assist device and IABP in postoperative biventricular failure].

Three patients with biventricular failure were managed postoperatively with the aid of a right ventricular assist device (RVAD) and intraaortic balloon pumping (IABP) with favorable results. Among these three cases, two had multiple rheumatic valvular disease with cardiac cachexia and underwent combined valve replacement. Another who was suffered from heart failure with a large ventricular septal defect and tricuspid regurgitation had a VSD closure and tricuspid valve replacement. In all patients, the weaning from pump oxygenator was difficult even with large doses of catecholamine. Therefore, the pump oxygenator was switched to RVAD for right ventricular assistance and IABP for left ventricular assistance because these patients had had right ventricular failure dominant biventricular failure preoperatively. Though case 2 was lost 64 days after the surgery by retroperitoneal bleeding due to inadequate anticoagulant treatment, the other two cases recovered successfully from postoperative biventricular failure and were discharged from the hospital. The indications of this method and the criteria for RVAD weaning were discussed.

Aged↗
PubMed1989

[The effect of aortic valve translocation and a few problems].

Aortic valve endocarditis is frequently associated with an aortic root abscess, so that it is difficult to insert a prosthetic valve. Between April, 1983 and June, 1988 we treated four out of seven patients with aortic valve endocarditis by translocation of the aortic valve, closure of the native coronary ostia, and placement of saphenous vein grafts on the coronary arteries. In each case, the operation was undertaken because of rapidly progressing heart failure. Infection was due to alpha-Streptococcus in two instances, to Staphylococcus epidermidis and fungus in the other cases. In one of the four patients, the prosthetic aortic valve was sutured to the ascending aorta and two saphenous vein grafts were placed on the proximal coronary arteries. In the other three patients, the composite Woven Dacron graft was used to replace the ascending aorta and two saphenous vein grafts were placed on the distal coronary arteries. One patient died one year postoperatively of LOS because of rapidly progressing coronary grafts ostial stenosis. The other three patients survived and doing well with satisfactory hemodynamic function and no infection. Translocation of the aortic valve for infective aortic valve endocarditis is a useful operative technique when conventional aortic valve replacement technique cannot be utilize.

Adult↗
PubMed1988

Modification of T cell receptor beta chain gene: the J2 region but not the J1 region of the T cell receptor beta chain gene is hypomethylated in human B cells and monocytes.

In order to determine the relationship between the generation of a 1.0 kb mRNA and methylation of the T cell receptor beta chain gene, we have analyzed the methylation state of the T cell receptor beta chain gene (T beta) in monocyte and B cell DNA, focusing on the J1 and J2 regions of this gene in human genomic DNA. We have observed that a portion of the J2 region of T beta rich with CpG sequences is nonmethylated in both monocyte and B cell DNA but that the J1 region is methylated in both cell DNAs. We suggest that the hypomethylation of the J2 region constitutes a condition in which a 1.0 kb truncated mRNA of the beta chain gene is expressed in B cells. We have also found that the CpG sequence 1.0 kb 3' to the last exon of the J2 was totally nonmethylated in B cell DNA but methylated in half of monocyte DNA. This difference in methylation between monocyte and B cell DNA may reflect the differential transcriptional activity in monocytes and B cells of a 1.0 kb mRNA of T beta.

B-Lymphocytes↗
PubMed1988

[The role of calcium in LH release from the pituitary by phorbol ester].

GnRH stimulates LH release from pituitary cells, and this process is calcium dependent. On the other hand, phorbol ester, 12-0-tetradecanoylphorbol-13-acetate (TPA), a potent activator of calcium- and phospholipid-dependent protein kinase (protein kinase C), stimulates luteinizing hormone (LH) release from rat pituitary cells. To investigate the involvement of the calcium dependent process in LH release by TPA, the effects of calcium channel antagonists, verapamil and nifedipine, on TPA-mediated LH release were compared with those of a GnRH superagonist, [D-Ala6] des-Gly10-GnRH N-ethylamide (GnRHa) in cultured pituitary cells. Furthermore, pituitary cells saturated with 45Ca2+ were stimulated by GnRHa or TPA and calcium mobilization after the stimuli were monitored. The pituitary cells from adult male rats were dispersed by trypsin and cultured for 3 days. Cultured pituitary cells were incubated with GnRHa or TPA in the presence of increasing concentrations of verapamil or nifedipine for 3hrs, and LH released into medium was measured by RIA for rat LH. For 45Ca2+ experiment, 3 day-cultured pituitary cells were saturated with 45Ca2+ (10(6) cells/1 microCi/100 microliters) and incubated with secretagogues for the indicated times. Incubations were terminated by filtration, and the radioactivity on the filter was measured by a beta-counter. LH release was stimulated by 0.1 nM TPA, and the maximum response at 10 nM TPA was 50% of the LH response to GnRHa. A23187 also stimulated LH release in relatively high concentrations (10(-5)-10(-4) M), and no additive stimulatory effect was observed when a half-maximal dose of TPA (10(-9) M) was added with increasing concentrations of A23187. Verapamil partially inhibited both GnRHa- and TPA-stimulated LH release, and a similar inhibitory effect on LH release was observed when nifedipine was incubated with GnRHa or TPA, although high concentrations (10(-5)-10(-4) M) of nifedipine stimulated LH release induced by GnRHa and TPA. GnRHa and TPA stimulated 45Ca2+ influx into the cells, and its peak was observed 15 and 30 seconds after stimulation, respectively, while GnRH antagonist did not mobilize 45Ca2+ until 120 seconds after stimulation. These results suggest that TPA-stimulated LH release from pituitary cells involves a calcium dependent process as does GnRH-stimulated LH release.

Animals↗
PubMed1988

Methylation patterns of the T cell receptor beta-chain gene in T cells, large granular lymphocytes, B cells, and monocytes.

We evaluated the methylation state of the T cell receptor beta-chain gene (T beta) DNA of T cells, large granular lymphocytes (LGL), B cells, and monocytes to determine whether methylation can be correlated with the reported transcriptional activity of this gene and whether this methylation pattern can be used as a marker for different leukocyte populations. By using the restriction enzyme isoschizomers, MspI and HpaII, we found that T beta of T cells was highly unmethylated, the gene in B cells and monocytes is highly methylated, and the methylation state of T beta of LGL is intermediate between that of T cells and B cells or monocytes. These results indicate that the methylation pattern of T beta can be a marker for T cells and LGL. The difference in methylation pattern of T beta between LGL and T cells indicated that most LGL were different from T cell populations. The methylation pattern of T beta in LGL DNA was also heterogeneous, in contrast to that of other leukocytes, suggesting that human peripheral blood LGL include several cell subsets. Only T cells, which synthesize full length 1.3-kb transcripts of T beta, have almost completely unmethylated CCGG sequences, indicating a good correlation between the reported level of 1.3-kb mRNA transcription from T beta and hypomethylation of this gene.

B-Lymphocytes↗
PubMed1988

Simultaneous expression of lymphoid and myeloid phenotypes in acute leukemia arising from myelodysplastic syndrome.

A 57-year-old female developed myelodysplastic syndrome (MDS) that terminated as a biphenotypic leukemia after exposure to chemoradiotherapy. Double staining of blast cells, using monoclonal antibodies specific for myeloid and lymphoid lineage, demonstrated that one-third of the leukemic cells simultaneously expressed the E rosette-associated antigen (OKT11) and myeloid-associated antigen (MY7). This finding suggests the possibility that some cases of MDS are clonal disorders that arise in a pluripotent stem cell that can also differentiate to T cell lineage.

Acute Disease↗