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Biomedical subjects

H Tohyama

Publications and source records attributed to H Tohyama.

At least 55 records · Page 3Linked to original sources

[Recent circumstances in the supply and demand of various blood products in Japan, and appropriate use of blood components or plasma protein derivatives].

In Japan, as in the United States and several other advanced countries, the use of fresh frozen plasma (FFP) and albumin has increased dramatically over the past 10 years. Especially in Japan the increase has been at least tenfold, and half of this usage has been for surgery. Most reviews of albumin usage acknowledge that there is a high ratio of wastage, or use in clinical circumstances without a firm scientific basis. Recently Japan has imported an enormous volume of various plasma fraction products such as albumin, Factor VIII etc., or plasma as raw material from foreign countries, especially the United States. As a result, Japan has come to monopolized a quarter of the albumin manufactured in the world, and has therefore received much internal and external criticism from or ethical standpoint. As countermeasures against shortage of these blood products, it will be necessary for doctors to use these blood products more sparingly and to increase the yield of volunteer donor's blood, especially plasma. More red blood cell concentrate should be utilized for hemorrhage in routine surgical operations. Because whole blood transfusion is rarely used except in cases of massive bleeding that cannot be stopped immediately, exchange transfusion has been performed in the United States and European countries recently. Transfusion of FFP is appropriately used only for replacement of coagulation factor deficiencies, massive transfusion etc. in the United States. It should be particularly noted that these carry the risk of transmission of diseases such as hepatitis and possibly AIDS. Albumin is an effective oncotic agent in the treatment of acute shock and in the maintenance of intravascular volume and cardiac output. However, albumin and FFP have no demonstrable effect in the general supportive management of chronic hypoproteinemia and undernutrition.

Blood Banks↗

Defective expression of HLA class I antigens: a case of the bare lymphocyte without immunodeficiency.

A case of the bare lymphocyte without apparent immunodeficiency was observed in a 33-year-old woman who had no history of severe infections but suffered from sino-bronchial disease. No HLA-A and -B antigens (class I antigens) were detected at the cell surface of lymphocytes, granulocytes, and platelets, but they were expressed, although at a reduced level, on the cultured B lymphoid cell line. T lymphocytes were normal in number and in the relative proportion of T4/T8 and responded to mitogens but not to PPD and candida. HLA-DR antigens (class II antigens) were present on B lymphocytes and showed intermediate MLR-stimulatory capacity, which made it possible to deduce the patient's HLA genotype. She was found to be homozygous at consanguinity for HLA-A, -B, and -DR antigens. The numbers of B lymphocytes, immunoglobulins, and complements were all in the normal range; there was, however, a low level of IgM. Two-dimensional gel analysis of class I antigens revealed the presence of normally expressed beta-2 microglobulins (B2M) and an apparently single set of class I heavy chains, allowing us to consider two alternative cellular mechanisms in this defect; the presence of one abnormal class I structural gene and the regulatory mechanism that acted in cis were suggested.

Adult↗

A novel leukocyte differentiation antigen: two monoclonal antibodies TM2 and TM3 define a 120-kd molecule present on neutrophils, monocytes, platelets, and activated lymphoblasts.

We produced two hybridomas by fusion of mouse myeloma cells with splenocytes from a mouse immunized with the THP-1 human monocytoid leukemia cell line. Two cloned hybridoma cell lines, designated as TM2 and TM3, were obtained. They secreted antibodies against a unique cell surface antigen expressed on all normal peripheral blood monocytes, neutrophilic granulocytes, platelets, and mitogen-induced lymphoblasts, some cells from patients with immature-type lymphoid leukemias. However, the antibodies reacted neither with large numbers of peripheral blood lymphocytes nor with red cells. Cross-blocking studies showed that these monoclonal antibodies recognized the same or a nearly positioned antigen epitope. Immunoprecipitation of THP-1 cell extract with TM2 or TM3 under reducing and nonreducing conditions yielded a specific band of mol wt equal to 120,000 daltons. This determinant appeared to be involved in granulocyte chemotaxis, since neutrophilic granulocytes exposed to TM2 or TM3 showed a significant decrease in chemotaxis toward endotoxin-activated serum. These two monoclonal antibodies did not affect O2- release or luminol-dependent chemiluminescence of neutrophils. Moreover, they did not alter platelet aggregation induced by thrombin. TM2 and TM3 will provide a new reagent in defining the linkage between lymphoid and myeloid differentiation and intermyeloid development.

Acute Disease↗

Interaction of human platelet membrane glycoproteins with collagen and lectins.

The binding of platelets to collagen is the first step in hemostasis. We attempted three approaches for elucidation of the chemical nature of receptors of human platelets for collagen. First, we examined the effect of platelet surface alteration by chymotrypsin treatment. On increasing the concentration of chymotrypsin, collagen-induced platelet aggregation and the release reaction decreased, an in parallel with this change, remarkable decrease of membrane glycoproteins IIb and V, as well as 400 kDa and 300 kDa membrane proteins, was observed. Secondly, effects of several lectins on the platelet-collagen interaction were examined. Lens culinaris agglutinin was found to specifically inhibit the platelet aggregation and release reaction induced by collagen. This inhibition appeared to be caused mainly by blocking of the collagen receptors on platelets by Lens culinaris agglutinin. Furthermore, Lens culinaris agglutinin was found to bind preferentially to glycoprotein IIb as identified by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis of platelet membranes followed by staining with 125I-Lens culinaris agglutinin. In addition, a polymerized preparation of Lens culinaris agglutinin induced platelet aggregation. Thirdly, the membrane component which could bind to collagen-Sepharose 4B was determined. Analysis by SDS-polyacrylamide gel electrophoresis combined with autoradiography or fluorography revealed that glycoprotein IIb was most enriched in the bound fraction to collagen. From these results, glycoprotein IIb is most likely a receptor for collagen on human platelet membranes.

Blood Platelets↗

Mixed passive hemagglutination with soluble platelet antigens.

Mixed passive hemagglutination (MPHA) test was established using platelet-supernatant and indicator cells coated with purified antihuman IgG antibodies. The supernatant was shown to contain HLA A and B antigens, platelet alloantigens and blood group A, B and H antigens released spontaneously from the platelets. Unlike the MPHA with platelet monolayer, the in vitro-formed immune complex (IC) or IC containing pathologic sera did not give positive reactions in the MPHA with platelet supernatants presumably due to relatively low Fc receptor activities of the supernatants. By means of this test, HLA A or B antibodies were demonstrated in sera of 32 (44%) of 72 patients with multiple platelet transfusions including 'cytotoxicity negative absorption positive' sera. This test would provide a sensitive procedure for cross-match of sera of recipients of platelet transfusion and screening of HLA A and B typing sera.

ABO Blood-Group System↗

Two-dimensional gel analysis of a second family of class II molecules by polymorphic HLA-DR4,5, and w9 monoclonal antibodies.

Human Ia-like, class II molecules were isolated by immunoprecipitation with monoclonal antibodies from various HLA-D/DR homozygous cell lines and were analyzed by two-dimensional gel electrophoresis. The monoclonal antibody PLM12 reacted with B cells carrying DR4, DR5, DRw6.2, and DRw9 phenotypes, and its reactivity perfectly correlated with the previously defined TB21 (MB3-like) specificity. Class II molecules detected by PLM12 were structurally distinct from those precipitated by the anti-DR monoclonal antibody NC1 on all HLA-DR4, DR5, DRw6.2, and DRw9 homozygous cell lines and showed polymorphism in heavy and light chains among these cell lines. The monoclonal antibodies PLM2 and PLM9 only reacted with B cells carrying DR5 and DRw6.2 and also detected a distinct set of class II molecules from those precipitated by NC1 but identical to those of PLM12. Thus, PLM2 and PLM9 serologically detected a new subtypic antigen of the PLM12-reactive class II molecules. Furthermore, the antibody NC1 precipitated two light chains and one heavy chain from HLA-DRw6.2 homozygous cell line EBV-Sh. The result indicated the presence of three sets of class II molecules: two in a DR family and another carrying the polymorphic determinants detected by PLM2, PLM9, and PLM12 in a second family.

Animals↗

The carbohydrate moiety of human platelet glycocalicin.

Glycocalicin, a predominant glycoprotein on the human platelet surface, has been purified from a platelet suspension by sonication, ammonium sulfate precipitation and acid treatment followed by chromatography on columns of wheat germ agglutinin-Sepharose and Sephacryl S-300. Ser/Thr-linked (O-linked) oligosaccharides were released by alkaline borohydride treatment, and fractionated by high performance liquid chromatography with an anion-exchange resin. The structure of a major oligosaccharide alditol separated by high performance liquid chromatography was investigated by a combination of compositional analyses, methylation and glycosidase treatments, and proposed to be a hexasaccharide alditol, NeuAc alpha 2-3Gal beta 1-4GlcNAc beta 1-6(NeuAc alpha 2-3Gal beta 1-3) N-acetylgalactosaminitol. We also found some sugar units which appeared to be intermediates in the biosynthetic pathway of the major hexasaccharide.

Blood Platelets↗

"Barrett's esophagus" adenocarcinoma: a case report.

A case of signet ring cell carcinoma of the lower thoracic esophagus of Barrett type without association of hiatus hernia is reported. The patient is doing well more than five years after esophagectomy combined with esophagogastrostomy. On the base of histological findings of the operative material, this tumor appears to have originated from the gastric type of mucosa with parietal cells, accessory cells and chief cells as it is lining the segment of the esophagus directly distal to the tumor. The basic anomaly in this case is believed to be misdifferentiation of the embryonic columnar epithelium to a gastric fundic type instead of a normal squamous type.

Adenocarcinoma↗