Search PubMed⌕ Search

Biomedical subjects

R Nagayama

Publications and source records attributed to R Nagayama.

At least 55 records · Page 3Linked to original sources
PubMed1984

Further characterization of platelet-type von Willebrand's disease in Japan.

We studied four patients who showed aggregation of platelets in platelet-rich plasma at lower concentrations of ristocetin than those required for normal platelet-rich plasma and who demonstrated an increased capacity of the platelets to bind normal von Willebrand factor. The four patients were from two Japanese families. Platelets from one family aggregated spontaneously in vitro, and platelets from both families aggregated upon the addition of normal plasma and cryoprecipitate, in the absence of ristocetin or other agonists. Analysis of the multimeric composition of von Willebrand factor by sodium dodecyl sulfate-agarose gel electrophoresis revealed a decrease in large multimers or a decrease in both large and intermediate multimers in plasma, but normal multimers in platelets. 1-Deamino-[8-D-arginine]-vasopressin caused by an immediate appearance of larger multimers in plasma, followed by the rapid disappearance of these multimers from circulating plasma. Analysis of platelet membrane glycoproteins from the patients showed that there were two distinct bands in the glycoprotein I region; one migrated in a slower region and the other in a faster region than normal glycoprotein Ib. We suggest that the platelet receptor abnormality in these patients is related to this abnormality of glycoprotein Ib.

Deamino Arginine Vasopressin↗
PubMed1983

[Indium-111-oxine labeled platelet scintigraphy for detection of intracardiac and intravascular thrombi].

This study was designed to evaluate the efficacy of scintigraphy by using 111In-oxine labeled platelets for the detection of either intracardiac or intravascular thrombi. Fourteen cases of thrombi diagnosed or suspected on the basis of either angiography or two-dimensional echography were examined. They included four cases of left ventricular thrombi, three of left atrial thrombi, four of vascular thrombi and three of inflammatory disease. Platelet samples from the patients were labeled by 111In-oxine according to the method originated by Yui et al. The labeling efficiency was 72.4 +/- 9.8%. The platelets retained good function except for collagen aggregability. Hot areas of high quality in the scintigram were demonstrated in six cases including two with left ventricular thrombi, two with left atrial thrombi and two with vascular thrombi. These areas accorded well with the findings of angiography, echography or surgery. The removed thrombi had a layer of aggregated platelets on the surface. Platelet survival was shortened in a case of prosthetic valve endocarditis without a hot area, and was normal in four out of five cases including two with a hot area. It is concluded that this method is potentially predictive in detecting thrombi.

Adult↗
PubMed1982

[Therapeutic results of DCMP therapy (2M-80) in acute non-lymphocytic leukemia--the relationship between the residual leukemic cells and duration of remission].

In this study the duration of complete remission by daunomycin, cytosine arabinoside (Ara-C), 6MP and prednisolone (DCMP) therapy using a large dose of Ara-C (200 mg) (protocol 2M-80) was compared with that of DCMP therapy with a low dose of Ara-C (80-160 mg) in acute non-lymphocytic leukemia (ANLL). In protocol 2M-80, the chemotherapy was continued until leukemic blasts in marrow were attained below 3%. Complete remission was induced in about 80% of ANLL patients in both chemotherapies. However, the duration of remission in protocol 2M-80 appeared to be much longer than that of DCMP therapy with a low, dose of Ara-C. This difference was dependent not on the consolidation and maintenance therapy, but on the total dose of Ara-C used and leukemic blasts left in marrow at the end of chemotherapy. This suggests that it is important to reduce leukemic blasts in marrow as low as possible by induction chemotherapy to obtain a long-term remission in ANLL.

Acute Disease↗
PubMed1982

[Infections during induction chemotherapy of acute leukemia and their control V. Clinical evaluation of a large dose of amikacin injected intravenously].

In this study, we treated severe infections (21 cases) accompanied with induction chemotherapy in 20 patients with acute leukemia by the combination of a large dose (600 approximately 1,200 mg/day) of amikacin with other antibiotics. Infections during induction chemotherapy of acute leukemia consisted of sepsis (8 cases), pneumonia (7) and others (6), and most of causative organisms were Gram-negative bacteria, such as Ps. aeruginosa (7 strains), Flavobacterium (5), Serratia (3), Ps. cepacia (2), E. coli (2) and others. The combination chemotherapy of a large dose of amikacin with other antibiotics was found to be effective (71.4%) for such infections. Side effects were negligible except for drug eruption. Therefore, a large dose of amikacin should be given for the treatment of severe infections accompanied with induction chemotherapy of acute leukemia.

Adolescent↗
PubMed1981

Von Willebrand disease associated with familial thrombocytopenia and increased ristocetin-induced platelet aggregation.

Two cases of von Willebrand disease (vWD) associated with familial thrombocytopenia were reported. The proband (daughter) and her father showed thrombocytopenia with large platelets and decreased von Willebrand factor activity (VIIIR:WF). Factor VIII procoagulant activity (VIII:C) and factor VIII-related antigen (VIIIR:AG) were normal, but both patients revealed an increased ristocetin-induced platelet aggregation and a qualitative abnormality of the factor VIII protein, which was characterized by fast electrophoretic mobility of VIIIR:AG and an abnormal elution of factor VIII-related activities on Sepharose 2B. DDAVP was hemostatically effective even in this thrombocytopenic patient undergoing a dental extraction.

Adult↗