Search PubMed⌕ Search

Biomedical subjects

Y Miyoshi

Publications and source records attributed to Y Miyoshi.

At least 199 records · Page 11Linked to original sources
PubMed1991

Immunohistochemical studies on enterokinase producing cells in the biliary tract.

The activation mechanism of pancreatic enzymes refluxing into the biliary tract in the anomalous arrangement of pancreaticobiliary ducts (APBD) remains unclear. In order to elucidate this activation mechanism, an immunohistochemical examination of both bile ducts and gallbladders was carried out on 20 patients with APBD to determine whether or not enterokinase (EK) producing cells exist in the biliary tract, by employing an avidin-biotin-peroxidase complex (ABC) method using a monoclonal antibody, hek-1. Immunoreactive EK was found in the metaplastic epithelium of the bile duct in 2 patients and the gallbladder in one, suggesting that EK production at the metaplastic epithelium is involved in an activation mechanism of pancreatic enzymes refluxing into the biliary tract. The same study was performed on the gallbladders of 62 patients without APBD, which revealed immunoreactive EK in some parts of the metaplastic epithelium of the gallbladder in 2 patients. Thus, in cases of pancreatic juice refluxing into the biliary tract regardless of the presence of APBD, we can not refute the possibility that refluxed pancreatic enzymes may be at least partly activated by EK produced at the metaplastic epithelium.

Adult↗
PubMed1991

Characterization of two bacteriocins produced by Clostridium perfringens.

Two types of bacteriocins were shown to be produced in succession by a strain of Clostridium perfringens SN-17. They were separated by diethylaminoethyl cellulose (DEAE) column chromatography at pH 8.5 with a linear concentration gradient of NaCl. One type of bacteriocin (named SN-a) was eluted at 0.07 M and the other type (named SN-b) was at 0.12 M. Each of these was partially purified in a series of column chromatographies: DEAE, Sephadex G-200 (or Bio Gel P-150), and hydroxyapatite. Specific activities of SN-a and SN-b after the last chromatography were at most 30- to 50-fold that of culture filtrate of the organisms. Chromatographed SN-a migrated as a single zone in polyacrylamide gel electrophoresis (PAGE) and the zone showed high biological activity. On the other hand, PAGE pattern of SN-b revealed the presence of a few contamination materials. The activity of SN-b after the last chromatography was hardly recovered from the gel but inactivated SN-b was identified in the gel by examining bacteriocin activity of the DEAE fractions recovered from the gel. The molecular weight of the SN-a and SN-b was determined to be about 70,000 and 100,000, respectively, by molecular sieve chromatography. These bacteriocins were very sensitive to protease but insensitive to DNase and RNase. Bacteriocins were both completely inactivated at 55 C and they were more stable in alkaline pH than in acidic pH. SN-a and SN-b were adsorbed in different ways on the surface of the producer and insensitive strains. Several differences and similarities between these 2 bacteriocins are discussed with special reference to the relationship between them.

Bacteriocins↗
PubMed1991

Frequent loss of heterozygosity at the MCC locus on chromosome 5q21-22 in sporadic colorectal carcinomas.

Recent studies have identified a gene on chromosome 5q, designated MCC (mutated in colorectal cancers), as a candidate for the putative colorectal tumor suppressor gene that is located at 5q21. We examined loss of heterozygosity (LOH) at the MCC locus and its vicinity in sporadic colorectal carcinomas, using 12 RFLP (restriction fragment length polymorphism) markers. One clone, L5.71, had been used to identify the MCC gene; all 12 markers also had tight linkage to the gene responsible for adenomatous polyposis coli. All 40 cases studied were informative with at least one marker, and 22 of them (55%) showed LOH at one or more loci. LOH in the tumors was more frequent in the immediate vicinity of L5.71 than in distant parts of the chromosome, and a common region of deletion was detected between markers L5.62 and 15A6. In one case, alleles were retained at L5.71 and at loci proximal to L5.71, but alleles were lost at loci distal to L5.71. In another case, both alleles were retained at L5.71 but alleles were lost at loci proximal and distal to L5.71. These results support the conclusion that a tumor suppressor gene for colorectal carcinoma is located within or around locus L5.71.

Chromosome Mapping↗
PubMed1991

Mutations of the adenomatous polyposis coli gene in familial polyposis coli patients and sporadic colorectal tumors.

We have isolated several genes in the chromosome 5q21 region tightly linked to hereditary familial polyposis coli (FAP) and Gardner's syndrome (GS). Two of these genes (MCC and APC) were found to be somatically altered by point mutation, deletion or insertion in tumors of sporadic colorectal cancer patients. One of them (adenomatous polyposis coli; APC) was also found to mutate in the germ-line of both APC and GS patients. The identification of these genes has significant implications for understanding the pathogenesis of colorectal neoplasia and for the diagnosis and counseling of individuals with inherited predispositions to colorectal cancer. Furthermore, in one colon carcinoma, we identified an interesting mechanism causing dysfunction of the APC gene. This gene was disrupted by a somatic insertion of a long interspersed repetitive element (LINE-1 sequence: L1) into the last exon. As an insertional sequence contains a 3' portion of the L1 consensus sequence including the poly(A) tract and an 8 bp target-site duplication was observed, this insertion is suspected to be caused by a retrotranscriptional insertion of one of the L1 sequences. This is the first case of the disruption of a tumor suppressor gene by the insertion of a movable genetic element.

Adenomatous Polyposis Coli↗
PubMed1991

[Effect of synthetic protease inhibitor on the sphincter of Oddi function in dogs].

Fundamental study in dogs have shown that the synthetic protease inhibitor has pharmaceutical properties characterized by effect on motility of the sphincter of Oddi. Synthetic protease inhibitors, gabexate mesilate and nafamostat mesilate have effects on motility of the sphincter of Oddi in dogs. The motor effect of synthetic protease inhibitor on the sphincter of Oddi has been investigated by manometric evaluation. Immediately after intravenous administration of gabexate mesilate (5, 10, 50, and 100 mg/kg/h) the motility of the sphincter of Oddi was inhibited dose-dependently, on the other hand after intravenous administration of nafamostat mesilate (0.5, 1, and 5 mg/kg/h) motility of the sphincter of Oddi was accelerated. Therefore it was suggested that these results shown some considerable problems in clinical use.

Animals↗
PubMed1991

[Changes in the megakaryocyte-platelet system in chronic neutrophilic leukemia].

Platelet functions and morphological changes of megakaryocytes were investigated in three cases with chronic neutrophilic leukemia (CNL). The bleeding time was prolonged, the ADP, collagen, epinephrine-induced aggregation of platelets decreased in one case. The adhesiveness, epinephrine-induced aggregation and adenine nucleotide content of platelets decreased in one other case. Megakaryocyte size in CNL was larger than in CML and this difference of the megakaryocyte sizes was related to DNA content distribution of the megakaryocytes. Atypical megakaryocytes were apparently found in one case. The present study suggests that CNL is a stem cell disorder.

Aged↗
PubMed1991

Effects of nitroglycerin on ATP-induced Ca(++)-mobilization, Ca(++)-activated K channels and contraction of cultured smooth muscle cells of porcine coronary artery.

Extracellular application of ATP transiently increases the cytosolic-free Ca++ concentration ([Ca++]i) in cultured smooth muscle cells of porcine coronary artery, and this activates large conductance Ca(++)-activated K (Kca) channels. In the present study effects of nitroglycerin (NG) and 4-aminopyridine (4-AP) on [Ca++]; and contraction were studied. 4-AP blocked Kca channels and enhanced the rise of [Ca++]i with oscillation, which led to contraction of the cells. NG activated the Kca channels of 300 picosiemens and inhibited 4-AP-induced contraction and oscillation of [Ca++]i. These results suggest that the vasorelaxant effect of NG involves hyperpolarization of the cell membrane by activating the Kca channels. NG also cause rapid decrease of [Ca++]i during the Ca(++)-mobilization by ATP in Ca-free solution. Similar effects were observed with cyclic GMP, suggesting that the effects of NG on the Kca channels and [Ca++]i were mediated by cyclic GMP.

4-Aminopyridine↗
PubMed1991

[Cytomolecular aspects of colorectal carcinoma].

This report reviewed recent remarkable progresses on the cytomolecular mechanisms in colorectal carcinogenesis. Colorectal carcinoma is a good model for the study of multi-step progression, because we can obtain adenomatous polyps which are considered as a precancerous form. Furthermore, a familial syndrome, which is characterized by numerous adenomas of the colon, is available for linkage analysis. Recently, the p53 and DCC genes have been identified as candidate tumor suppressor genes on chromosome 17p and 18q respectively. In this paper, we present the multiple genetic alterations in colorectal carcinoma, including activation of K-ras gene and inactivation of tumor suppressor gene such as p53 and DCC genes as well as loss of heterozygosity and approach to the gene responsible for adenomatous polyposis coli by reverse genetics.

Adenomatous Polyposis Coli↗
PubMed1991

[Acute megakaryoblastic leukemia developing 11 years after diagnosis of essential thrombocythemia].

A 57-year-old man was diagnosed to have essential thrombocythemia (ET) in July 1977. He was doing well with continual medication of carboquone but was hospitalized because of slight unconsciousness and gait disturbance in May, 1988. His laboratory data were as follows: WBC count 81,600/microliters with 55% of blasts with cytoplasmic blebs, Hb 10.2 g/dl, and platelet count 2.6 x 10(4)/microliters. Bone marrow aspiration revealed hypercellular marrow with 72.8% blasts. Chromosomal analysis showed tetraploidy with 7p+ and 19p+. Cytochemistry of blasts showed the positivity for platelet peroxidase and CDw 41. The diagnosis of acute megakaryoblastic leukemia was made. Meningeal leukemia was also suspected by the cerebrospinal fluid data, and cytarabine was intrathecally injected. Then the percent of blasts of peripheral blood gradually decreased and the data of cerebrospinal fluid improved. However, several days later the patient became comatose probably due to cerebral bleeding, and died. In this case, two possibilities were considered (1) that a blastic transformation to acute leukemia from ET, and (2) that a secondary leukemia developed as a result of the chemotherapy, independently of ET. Since there was no evidence of myelodysplastic syndrome, it was concluded that this case represented a blastic transformation of ET.

Blast Crisis↗
PubMed1991

[Expression of P53 and heat shock protein in colorectal tumors: an immunohistochemical study].

Abnormality of tumor suppressor gene p53 is supposed to be associated deeply with colon carcinogenesis. We have examined the aberrant expression of the p53 protein in human colorectal cancer or adenomatous tissues immunohistochemically using monoclonal antibody PAb 1801. In microwave-fixed colorectal tissues, p53 was successfully detected in more than 60% of carcinomas. Specific signal for p53 was restricted in the nuclei of cancer cells, while no staining was observed in adjacent normal mucosa. The incidence of p53 expression in colorectal carcinomas was not affected by pathological features such as tumor size, histological grade, nor depth of invasion. In about 10% of colorectal adenomas, weak signal was detected in a few adenomatous glands. Heat shock protein of 72 kDa (HSP72), known to form complex with the mutant-type of p53 in tumor cells, was also detected immunohistochemically in 25% of p53-positive cases. In these cases, high incidence of lymphnodal or distant metastasis was observed, which suggests that expression of both p53 and HSP72 may indicated biological malignancy of the colorectal carcinomas.

Biomarkers, Tumor↗
PubMed1991

[Malignant histiocytosis with complex chromosomal abnormality: successful treatment with CHOP-E chemotherapy].

A 43 year-old man admitted to our hospital because of fever and splenomegaly. Laboratory findings were as follows: Hb 9.5 g/dl, Plts 4.9 X 10(4)/microliter, LDH 2,348 IU/l. Bone marrow findings showed tumor cell 47% with or without phagocytosis. The tumor cells were stained positive lysozyme and alpha 1 antitrypsin. Cytogenetic study was 47, XY, -7, -8, +9, -11, -12, -19, -21, 3q+, 6p+, +6 markers. This case was diagnosed as malignant histiocytosis. Complete remission was achieved with CHOP-E chemotherapy. Remission has been maintained with repeated this therapy. Etoposide deserves a good evaluation in the treatment of malignant histiocytosis. Some cases of malignant histiocytosis with a t(2; 5) (p23; q35) translocation were often reported in Europe and America, while there was no specific chromosomal abnormalities with malignant histiocytosis in Japan.

Adult↗
PubMed1990

Monoclonal antibody against human enterokinase and immunohistochemical localization of the enzyme.

A monoclonal antibody, hek-1, was raised against enterokinase or enteropeptidase that had previously been partially purified from human duodenal fluid. Hek-1 showed staining of two glycoprotein bands of relative molecular weights of 260,000 and 240,000 on immunoblot analysis of partially purified enterokinase and of ammonium sulfate fraction of duodenal fluid. An enzyme immunoassay for human enterokinase was developed, making use of hek-1. Sensitivity to enterokinase was 20 times higher than that of the conventional assay where BAPA was used as a substrate. The immunohistochemical study with hek-1 showed staining of the brush border membrane and some goblet cells of the duodenum and upper jejunum but no staining of the colon epithelium.

Animals↗
PubMed1990

[Philadelphia chromosome positive acute mixed lineage leukemia with bcr (M-BCR-1) rearrangement].

We report two cases of Philadelphia (Ph1) chromosome positive acute mixed lineage leukemia (AMLL) with breakpoint cluster region (bcr) (M-BCR-1) rearrangement. A 31 year-old-man (case 1) and a 42 year-old-woman (case 2) were admitted to our hospital for further evaluation of leucocytosis with atypical blasts. Each case was diagnosed as having bilineal type of AMLL because: (1) blasts in each case consisted of larger myeloid cells positive for myeloperoxidase and small lymphoid cells positive for PAS, and blasts in case 2 were positive for TdT; (2) blasts in case 1 expressed B lymphoid associated antigen; (3) Southern analysis in each case showed clonal rearrangements of both the immunoglobulin heavy chain and the T cell receptor beta gene. These two cases demonstrated the Ph1 chromosome and rearrangement of the bcr (M-BCR-1) gene, but none of splenomegaly, basophilia, and additional chromosome abnormalities were observed. In addition, after achieving remissions, they didn't revert to chronic phase of chronic myelogenous leukemia (CML) and showed normal neutrophil alkaline phosphatase scores, and the Ph1 chromosome disappeared completely in case 1 and coexisted with the normal chromosome in case 2. These findings suggest that diagnosis of both cases should not be CML blast crisis (BC) but Ph1 positive acute leukemia, and Ph1 positive AMLL may be a distinct clinical entity to be distinguished from CML-BC.

Adult↗
PubMed1990

[A hepatocellular carcinoma (HCC) with intrahepatic bile duct dilatation and right lobe atrophy following percutaneous ethanol injection therapy].

Reported is the case of a 67-year-old man with an HCC who was being treated by percutaneous ethanol injection therapy (PEIT). After a year, CT and ultrasonography demonstrated the dilatation of the intrahepatic bile duct and the atrophy of the right lobe. Endoscopic cholangiography also showed stenosis of the right hepatic duct. This severe complication and injury to the hepatic duct and portal vein was determined as having occurred because of treatment by PEIT.

Aged↗
PubMed1990

[Megaloblastic anemia and platelet function--a qualitative platelet defect in pernicious anemia].

In order to know the entities of platelet defect in pernicious anemia, we investigated platelet functions in ten cases with pernicious anemia. Three of the cases had total gastrectomy. Five cases showed thrombocytopenia and four cases revealed prolongation of Ivy bleeding time. Decreased adhesiveness was observed in three cases. Various abnormalities in platelet aggregation were observed. However, almost all of the cases showed remarkable improvement of decreased platelet functions after the therapy of Vitamin B12 injection. The results of adenine nucleotides in platelets and the release of them following collagen or epinephrine aggregation were analysed in comparison with normal platelets. The ADP was definitely decreased and the ATP/ADP ratio was increased. In addition, the release of ATP and ADP at collagen or epinephrine induced aggregation was markedly decreased, and after the therapy of Vitamin B12, the decrease of adenine nucleotide release remarkably increased. In summary, the acquired defects of platelet function in pernicious anemia are regarded as a secondary storage pool disease, and its defects improve after Vitamin B12 therapy.

Adult↗