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J Yamamoto

Publications and source records attributed to J Yamamoto.

At least 217 records · Page 12Linked to original sources
PubMed1993

Identification of the regulatory site in smooth muscle calponin that is phosphorylated by protein kinase C.

F-actin and tropomyosin inhibited the phosphorylation of calponin by protein kinase C, and the phosphorylation reduced the binding of calponin to F-actin and tropomyosin. Labeled phosphate from [gamma-32P]ATP was retained both on the chymotryptic NH2-terminal 22-kDa fragment, which contains the actin-, tropomyosin-, and calmodulin-binding regions, and on the COOH-terminal 12-kDa fragment. Fractionation of tryptic 32P-labeled peptides by high performance liquid chromatography allowed isolation of three phosphopeptides (designated T1, T2, and T3), each of which was located in three repeating amino acid motifs of calponin. Both the relative initial rates and extent of phosphorylation decreased in the order T2 > T3 > T1. Both serine and threonine residues were phosphorylated in T1 (GASQAGMTAPGTK), and only a threonine residue was phosphorylated in T2 (FASQQGMTAYGTR) and in T3 (GASQQGMTVYGLPR). As the 22-kDa fragment contained only T2, the phosphorylation site in T2 appeared to regulate the binding of calponin to F-actin and tropomyosin. The amino acid sequence of T2 indicates that protein kinase C phosphorylates Thr184. Thus Thr184 is the preferred site of phosphorylation and is functionally the most important of the sites phosphorylated by protein kinase C in smooth muscle calponin.

Actins↗
PubMed1993

Nucleotide sequence of the cDNA encoding nucleoside diphosphate kinase II from spinach leaves.

The primary structure of nucleoside diphosphate (NDP) kinase II, one of the two isozymes found in spinach leaves, has been deduced from its cDNA sequence. NDP kinase II comprises 233 amino acid residues and has a molecular mass of 26,107 Da, which is larger than that of the purified NDP kinase II subunits (18 kDa) by about 8 kDa, suggesting that NDP kinase II might be post-translationally processed. Homology was found between the sequence of spinach NDP kinase II, and the sequences of spinach NDP kinase I, rat NDP kinases alpha and beta, Dictyostelium discoideum NDP kinase, the human Nm23-H1 and Nm23-H2 proteins and the awd protein of Drosophila melanogaster.

Amino Acid Sequence↗
PubMed1993

The antithrombotic effect of low molecular weight synthetic thrombin inhibitors, argatroban and PPACK, on He-Ne laser-induced thrombosis in rat mesenteric microvessels.

The antithrombotic effect of low molecular weight synthetic thrombin inhibitors, argatroban ((2R, 4R)-4-methyl-1-[N2-[(3-methyl-1, 2, 3, 4-tetrahydro-8-quinolinesulfonyl)-L-arginyl]-2-piperidinecarbox ylic acid monohydrate]) and PPACK (D-phenylalanyl-L-prolyl-L-arginyl-chloromethyl ketone) on He-Ne laser-induced thrombosis in rat mesenteric microvessels was studied. Both inhibitors showed a significant antithrombotic effect at 0.5 mg/kg which lasted for 50 min and 50-60 min using argatroban and PPACK, respectively. A dose-dependent effect was observed in arterioles and venules. The results suggest that thrombin plays an important role in the formation of a platelet thrombus in vivo.

Amino Acid Chloromethyl Ketones↗
PubMed1993

Expression of human minor histocompatibility antigen on cultured kidney cells.

Incompatibility of human minor histocompatibility (hmH) antigens can induce rejection of grafts in organ transplantation and graft-versus-host reactions in bone marrow transplantation. In spite of their importance in clinical transplantation, hmH antigens are not well studied. Previous studies have demonstrated the expression of hmH antigens on T and B cells, hematopoietic progenitor cells and keratinocytes. We have for the first time demonstrated the expression of hmH antigens on cultured kidney cells using HLA-B35-restricted, hmH antigen-specific cytotoxic T lymphocyte (CTL) clones, which were previously established from a patient who rejected two kidneys from HLA-identical sisters. The CTL clones could not kill cultured kidney cells. Since cultured kidney cells expressed very low levels of HLA class I antigens it was thought that their failure to be killed by the CTL clones was due to lack of expression of HLA-B35 antigens. After induction of class I antigens on cultured kidney cells by interferon-gamma (IFN-gamma), the IFN-gamma-treated cultured kidney cells were killed by the CTL clones. Furthermore, we isolated hmH antigens as peptides from cultured kidney cells after treatment with IFN-gamma. These results indicate that cultured kidney cells express hmH antigens when HLA class I antigen is induced by IFN-gamma and hmH antigens on cultured kidney cells are recognized by T cells as peptides presented by HLA-B35 molecules.

Antibodies, Monoclonal↗
PubMed1993

Lack of prognostic value of immunoreactivity for p62 oncoprotein in colorectal carcinoma.

Immunohistochemical staining for c-myc p62 oncoprotein (p62) was performed in 59 colorectal carcinomas using mouse monoclonal antibody against human c-myc protein (MYC1-6E10). The immunoreactivity for p62 was intense in 22 (37.3%), and weak in 37 (62.7%) of the tumors. Advanced disease and nodal metastasis were more frequently seen in tumors showing intense staining but the difference did not reach statistical significance. Sixteen patients have died of the disease but overall survival rates did not differ between patients with tumors showing intense staining and those with tumors showing weakly staining. In 50 patients undergoing grossly curative resection, local or distant metastasis developed in 15 patients. Immunoreactivity for p62 had no effect on the rate of recurrence or disease free survival rates in these 50 patients undergoing grossly curative resection. The present study revealed that the immunoreactivity for p62 had no prognostic value in colorectal carcinoma.

Adult↗
PubMed1993

Effect of vitamin A on methotrexate cytotoxicity in L1210 murine leukemia cells in culture.

Vitamin A (VA) protects the small intestine from methotrexate (MTX)-induced damage. However, before VA can be used as a remedy to protect cancer patients from MTX-induced damage to the intestine, it is essential to clarify whether or not it disturbs the antitumor activity of MTX. This study investigated the effect of VA on the antitumor activity of MTX in vitro in L1210 murine leukemia cells. The incorporation of [6-3H]-thymidine and [6-3H]-uridine, [5-3H]-uridine, and [4,5-3H]-leucine into DNA, RNA, and proteins, respectively, was examined to evaluate this effect. The incorporation of thymidine, the uridines, and leucine decreased dose-dependently in MTX-treated L1210 cells and profoundly in the MTX plus VA-treated L1210 cells, since VA itself had a cell-killing activity. Thus, MTX depressed the growth of L1210 cells dose-dependently and this depression was not affected by the presence of VA. The present study proved in L1210 murine leukemia cells in vitro that VA did not disturb the antitumor activity of MTX.

Animals↗
PubMed1993

Alcoholism in Peru.

OBJECTIVE: Alcoholism is a problem of worldwide concern. Full appreciation of this international problem requires that adequate diagnostic measures be constructed and that comparable measures for different cultures be available so that valid differences in prevalence across cultures can be detected. A Spanish-language version of the Diagnostic Interview Schedule (DIS) has been used for epidemiologic studies of alcohol abuse and dependence in Los Angeles Mexican-Americans and mainland Puerto Ricans, and the authors used the same instrument to conduct a similar study in Peru. METHOD: A population sample (N = 815) from the Independencia district of Lima, Peru, was chosen for interviews with a revised form of the Spanish translation of the DIS. Lifetime prevalence rates of alcoholism and other DSM-III diagnoses were determined. RESULTS: The prevalence of alcohol abuse or dependence was higher among the men (34.80%) than among the women (2.46%), but the onset for women was earlier. Alcoholism was strongly associated with antisocial personality disorder and with drug abuse or dependence. CONCLUSIONS: The prevalence of alcoholism for the Peruvian men is higher than prevalences for men in U.S. studies, but the prevalence among the Peruvian women is one of the lowest reported. The high prevalence among men is likely due to cultural mores but may also be linked to the stresses found in impoverished societies undergoing rapid social, cultural, and economic change.

Adolescent↗
PubMed1993

The association between fast-flushing response and alcohol use among Japanese Americans.

This study investigated the association between the flushing response and alcohol use among Japanese Americans in the greater Los Angeles area. Epidemiolocial data collected through a telephone survey and a mail survey were utilized to test the flushing-alcohol use relationship in the Japanese population, and to explore the effects of socioenvironmental variables. Results showed that, as predicted, those Japanese Americans who exhibited the fast flushing response tended to drink less than those who did not flush, in the general community sample, but the relationship was weaker in the college student sample. Logistic regression analysis identified several covariates that predicted alcohol use among the general community residents: being a male, being single and being of the third/fourth generation. A separate logistic regression analysis with the college students only revealed a moderately significant interaction effect of flushing response and "Greek" affiliation (membership in a campus fraternity or sorority) on alcohol use (i.e., 6 drinks or more in a 24-hour period), indicating that the social context appeared to have a moderating effect on the relationship between the flushing response and alcohol use among Japanese Americans. Eighty out of 300 individuals completely abstained from alcohol consumption and therefore did not know if they possessed the fast-flushing response. Results were discussed with respect to further investigation of the role played by ALDH-I deficiency in varying social situations in the Japanese population.

Adult↗
PubMed1993

Follow-up examination schedule of postoperative HCC patients based on tumor volume doubling time.

The tumor volume doubling time of 27 recurrent hepatocellular carcinoma nodules measuring < or = 2.0 cm in diameter discovered after hepatectomy in 19 patients was analyzed by ultrasonography for 31 to 331 days. The tumor volume doubling time ranged from 39 to 420 days before specific treatment, with a mean of 112 days and a median of 80 days. It correlated with age and intrahepatic site of recurrence, which was sometimes the same lobe as that of the prior hepatocellular carcinoma, sometimes not. The tumor volume doubling time also tended to correlate with hepatitis C antibody status and initial tumor diameter. The tumor volume doubling time was, however, independent of sex, hepatitis B surface antigen status, number of recurrent tumors, initial serum alpha-fetoprotein level, interval between hepatectomy and recurrence detection, and associated liver disease. On the basis of the shortest tumor volume doubling time of the recurrent hepatocellular carcinoma nodules, we recommend that US and/or CT be performed at least every four months to screen for small recurrent carcinomas in postoperative patients.

Aged↗
PubMed1993

Combined hepatocellular carcinoma and cholangiocarcinoma: clinical features and computed tomographic findings.

Clinicoradiological features were studied in 20 patients with 22 mass lesions of combined hepatocellular carcinoma and cholangiocarcinomas and findings of computed tomography in 12 of these patients with 14 hepatocellular carcinoma-cholangiocarcinomas. Five of these patients also had single overt hepatocellular carcinomas. The incidence of hepatocellular carcinoma-cholangiocarcinoma was 3.3% among the patients with primary liver cancer treated in our hospital. HBsAg was present in 25%, and increased levels of serum alpha-fetoprotein (> 200 ng/ml) and carcinoembryonic antigen (> 5 ng/ml) were found in 25% and in 47%, respectively. Associated cirrhosis was present in 60%. Analysis of 14 hepatocellular carcinoma-cholangiocarcinomas in 12 patients in whom the enhancement pattern on dynamic computed tomography and pathological findings could be studied and compared suggested three tumor types. Nine lesions (type A) were demonstrated only as areas with high-density peripheries in the early phase of enhancement that evolved into a pattern of peripheral low density and central high density in the late phase. Four masses (type B) were shown as hyperdense tumors (early phase) that changed to low density in the late phase. One mass (type C) was seen as a low-density lesion that did not change. Histopathologically, type A comprised hepatocellular carcinoma-predominant components in the peripheral area, cholangiocarcinoma-predominant components with abundant fibrous stroma in the central area and a tissue transitional between the two in the midzone. By contrast, two of four type B masses comprised hepatocellular carcinoma with scattered cholangiocarcinoma components throughout the tumor.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

[Quantitative evaluation of 111In-antimyosin Fab myocardial imaging in acute myocardial infarction patients].

Quantitative evaluation of 111In-antimyosin Fab myocardial (InAM) imaging was performed in 15 patients with acute myocardial infarction to evaluate which organ is the most appropriate for the control of myocardial accumulation, to compare the quantitative method with the conventional visual method, and to study which clinical indices correlate with the InAM quantitative evaluations. InAM images demonstrated the myocardium with 31 +/- 6 mean counts/pixel, lung with 14 +/- 4, upper mediastinum with 20 +/- 5, middle mediastinum with 26 +/- 5, and liver with 75 +/- 10. We considered the lung to be the most appropriate control organ for quantitative evaluations of InAM imaging, because it could be separated from the myocardium, and the measurement range was narrow. The InAM uptake index [IUI = (myocardial counts-lung counts)/lung counts] was calculated as the index of myocardial accumulation. Visual evaluations of myocardial accumulation on InAM images were classified into three grades. The IUI of grade 1 (slight) was 0.98 +/- 0.19, grade 2 (moderate) was 1.34 +/- 0.38, and grade 3 (severe) was 1.97 +/- 0.19. Visual grading was nearly in accordance with the IUI, although it was difficult to distinguish visually between grades 1 and 2. Measurement of wall motion by left ventriculography showed that reduced wall motion was associated with an IUI of 1.01 +/- 0.18 and dyskinesis with an IUI of 1.92 +/- 0.16, showing IUI can indicate regional myocardial damage. However, IUI was not correlated with indices of the overall left ventricular function, such as ejection fraction, cardiac index, and peak creatine kinase level.

Antibodies, Monoclonal↗
PubMed1993

Liver abscess after percutaneous ethanol injection (PEI) therapy for hepatocellular carcinoma. A case report.

We present a case of liver abscess after percutaneous ethanol injection (PEI) therapy for the treatment of recurrent hepatocellular carcinoma (HCC). The 56-year-old woman had a past history of cholecystoduodenostomy for cogenital dilatation of the bile duct, and pneumobilia was observed in the intrahepatic bile ducts prior to PEI. The abscess was successfully treated by percutaneous abscess drainage and antibiotic therapy. Klebsiella pneumonia, one of the most common causative organisms of biliary tract infection, was isolated from the abscess. Thus, biliary tract infection related to the previous biliary-enteric anastomosis operation may have been one of the causative factors in the liver abscess in this patient. The rare experience reported here suggests that a careful search for coexistent abscess at the time of PEI is important in HCC patients with biliary-enteric anastomosis, especially in those with pneumobilia.

Carcinoma, Hepatocellular↗
PubMed1993

[Intrahepatic cholangiocarcinoma: proposal of new macroscopic classification].

From the analysis of 19 resected intrahepatic cholangiocarcinoma (ICC) from 1980 to 1991 in the National Cancer Center Hospital, we classified them into three subcategories, mass-forming ICC, infiltrating ICC and papillary ICC, according to the morphologic pattern. Mass-forming ICC, which made an apparent mass lesion in the liver, showed a spread based on the intrahepatic metastasis with a frequent remnant hepatic recurrence. Infiltrating ICC caused a stricture or an obstruction of intrahepatic bile duct with a spread along the Glisson's capsule without forming a mass in the liver and yielded no remnant liver recurrence except for a local recurrence in the patient with positive surgical margin. Intraductal papillary ICC, which appeared a special type of ICC, developed a papillary projection into the ductal lumen. Three patients of mass-forming ICC and one of papillary ICC survived more than 5 years. The different biologic behaviour should be considered when formulating an operative procedure for each type of ICC.

Adult↗
PubMed1993

Long-term results after resection of hepatocellular carcinoma: experience of 480 cases.

The long-term outcome in 480 patients with primary hepatocellular carcinoma (HCC) who underwent hepatic resection between 1980 and 1990 was investigated. Overall 5- and 10-year survival rates were 44.1% and 17.8%, respectively, with a hospital mortality rate of 3.1%. The survival of patients who underwent curative resection was better than that of patients treated with noncurative resection. Tumor invasiveness, defined by the presence of vascular invasion and/or intrahepatic metastases, was a major prognostic factor for early recurrence in the patients treated with curative resection. The effect of tumor size and number on prognosis was attributable to a strong correlation with tumor invasiveness. One-third of patients with multiple lesions were considered to have multicentric disease, and their prognosis was better than that of patients with invasive lesions. The width of the resection margin did not affect the prognosis. An unfavorable effect of associated liver disease, especially cirrhosis, was prominent in the later period. A beneficial effect of anatomically systematic resection was apparent in non-cirrhotic patients with non-invasive HCC.

Adolescent↗
PubMed1993

Repeat hepatic resection for recurrent hepatocellular carcinoma.

During the last 12 years, hepatic resection was carried out on 268 patients with a diagnosis of hepatocellular carcinoma. Of these, 78% developed tumor recurrence in the remaining liver within 5 years. The indications for repeat hepatectomy were evaluated in the same way as for the first operation. Eighteen second hepatic resections and six third hepatic resections were performed 4 to 63 months after the first hepatectomy, with no operative deaths. The cumulative survival rate of these 24 patients was 87.1% at 3 years, 87.1% at 5 years and 72.6% at 7 years after the first hepatic resection, respectively. The present results show that repeat hepatectomy can be safely indicated for recurrent tumors in patients whose liver functional status has been relatively stable since the first hepatic resection.

Adult↗