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Y Nagamine

Publications and source records attributed to Y Nagamine.

At least 109 records · Page 6Linked to original sources

Exon-intron boundary sliding in the generation of two mRNAs coding for porcine urokinase-like plasminogen activator.

We have analyzed four full-length cDNA clones to porcine urokinase-like plasminogen activator (uPA) mRNA. DNA sequencing revealed a deletion of 27 nucleotides in one cDNA. The comparison of cDNA and genomic sequences indicated that this length polymorphism was due to an alternative splicing of two potential 5' splice sites to a unique 3' splice site. As the difference was 27 nucleotides (corresponding to 9 amino acids) and there was no termination codon within the same reading frame in this region, the two different mRNAs might be equally biologically active.

Animals↗

Induction and desensitization of plasminogen activator gene expression by tumor promoters.

Tumor promoting phorbol esters and mezerein strongly induced plasminogen activator (urokinase, uPA) synthesis in porcine kidney cell cultures (LLC-PK1). Induction was due to increased uPA-mRNA levels which rose from 10 to 300 molecules/cell within 2 h of exposure to 16 nM phorbol myristate acetate. We have compared the action of tumor promoters with that of 8-bromo-cAMP, another potent inducer of uPA; the similarities between the two kinds of induction were: both involved transcriptional activation of the uPA gene; both were rapid in onset, changes in transcription rate being detectable within 10-20 min; the initial rates of transcription and uPA-mRNA accumulation were substantial and in the same order of magnitude; neither class of inducer required protein synthesis to stimulate uPA transcription. The main contrast between the two types of agents was that the uPA response to tumor promoters was transient whereas that to cAMP compounds was sustained: cultures rapidly lost their response to tumor promoters within 2 h after initial exposure while retaining responsiveness to cAMP-related agents. The cells developed a specific drug-induced desensitization which was slowly reversed after tumor promoters were removed from the culture medium. Since protein kinase C is now well established as the receptor for phorbol-derived and several other tumor promoters it will be of interest to determine whether desensitization occurs at the level of receptor.

8-Bromo Cyclic Adenosine Monophosphate↗

Cloning, nucleotide sequencing and expression of cDNAs encoding mouse urokinase-type plasminogen activator.

Controlled extracellular proteolysis is catalyzed in part by the secretion of plasminogen activators. As a step in the study of the expression of these enzymes in mouse tissues, we have isolated five cDNAs encoding the mouse urokinase-type plasminogen activator from a cDNA library prepared with size-selected mRNA from MSV-transformed 3T3 cells. The longest cDNA insert contains the entire coding region of mouse urokinase, 58 base pairs of the 5' non-coding region, and the entire 3' non-coding region, which is 942 base pairs long. The deduced protein sequence, which starts with a signal peptide of 20 amino acids, shows extensive homology to that of human and porcine urokinase. However, in contrast to these enzymes, mouse urokinase contains no N-glycosylation site. Bacteria harbouring one of the recombinant plasmids synthesize and secrete into their periplasm a protease indistinguishable from mouse urokinase.

Amino Acid Sequence↗

Gene expression and cAMP.

By comparing the 5'-flanking region of the porcine gene for the urokinase form of plasminogen activator with those of other cAMP-regulated genes, we identify a 29-nucleotide sequence that is tentatively proposed as the cAMP-regulatory unit. Homologous sequences are present (i) in the cAMP-regulated rat tyrosine aminotransferase, prolactin, and phosphoenolpyruvate carboxykinase genes and (ii) 5' to the transcription initiation sites of cAMP-regulated Escherichia coli genes. From this we conclude that the expression of cAMP-responsive genes in higher eukaryotes may be controlled, as in E. coli, by proteins that form complexes with cAMP and then show sequence-specific DNA-binding properties. The complex formed by cAMP and the regulatory subunit of the type II mammalian protein kinase might be one candidate for this function. Based on several homologies we suggest that this subunit may have retained both the DNA-binding specificity and transcription-regulating properties in addition to the nucleotide-binding domains of the bacterial cAMP-binding protein. If this were so, dissociation of protein kinase by cAMP would activate two processes: (i) protein phosphorylation by the catalytic subunit and (ii) transcription regulation by the regulatory subunit.

Animals↗

Skull metastasis of thyroid carcinoma. Study of 12 cases.

Over the past 33 years the authors have treated 12 cases of skull metastasis from thyroid carcinoma, accounting for 2.5% of a total of 473 cases of thyroid cancer. A study of these 12 cases revealed the following characteristics. The mean age of the patients was 60.4 years and the predominant incidence was in the seventh decade of life. The incidence of skull metastasis from thyroid cancer was higher among women than among men. The primary sign was a soft hemispheric tumor resting on the skull. The tumors were rich in vascularity with osteolytic changes in the skull. The average period from diagnosis of the thyroid tumor until thyroidectomy was 14.3 years, and until discovery of the skull metastasis was 23.3 years. The clinical course was thus very long. The most frequent histopathological presentation was follicular adenocarcinoma. Such lesions were morphologically well differentiated, with little pleomorphism and atypism, but detailed examination showed infiltration into the vascular lumen or capsule. The mean survival time in these patients was 4.5 years from the time of diagnosis. The prognosis in this lesion was relatively poor, considering its long clinical course.

Adult↗

[Chemical embolization using estrogen for aneurysmal bone cyst of the skull: case report].

A case of aneurysmal bone cyst of the fronto-parietal bone was reported. The patient was a 48-year-old female with the complaints of conjunctival hyperemia and exophthalmus of the right side. Right selective externography revealed both arteriovenous fistula between right middle meningeal artery and diploic vein, and abnormal venous pooling draining into right superior ophthalmic vein. These symptoms probably caused by the increased intraorbital venous pressure in the right side. Skull plain film and CT scan showed blow-out appearance of right fronto-parietal bone in accordance with the enlargement of diploic space. The bulged area and the rest of the affected part of the bone presented faintly coarse "soap bubble" pattern. And the affected bone, being radiolucent, had well demarcated borders which are distinct and smooth, with faint sclerosis. Both arteriovenous fistula and clinical symptom have disappeared completely by the continuous injection of conjugated estrogen into the right external carotid artery. This is the first case that proved chemical embolization using estrogen will effect a cure in the treatment of aneurysmal bone cyst.

Bone Cysts↗

cDNA and gene nucleotide sequence of porcine plasminogen activator.

We have isolated cDNA and genomic clones coding for porcine plasminogen activator (urokinase, uPA). The cDNA is 2375 nucleotides long: it consists of a 5'-non-coding region (104 nucleotides), an open reading frame of 1329 nucleotides, and 3'-non-coding region of 942 nucleotides apart from the poly A tail. The genomic segment corresponding to the transcribed sequence is 5.85 kb long; it is composed of 11 exons and 10 introns. The 5'-flanking genomic region contains a number of sequences of potential regulatory significance, including possible hormone receptor binding sites and a sequence which we tentatively propose may be involved in activation of transcription by cAMP. The full sequence of both cDNA and genomic clones, the latter including 1.3 kb of flanking region, is presented and discussed, and the deduced amino acid sequence compared with that of human uPA.

Amino Acid Sequence↗

A pSC101-derived plasmid which shows no sequence homology to other commonly used cloning vectors.

We have constructed a plasmid cloning vector, pGB2, which is derived from the Escherichia coli plasmid pSC101. The plasmid, which specifies resistance to spectinomycin and streptomycin, contains unique restriction sites for the enzymes HindIII, PstI, SalI, BamHI, SmaI and EcoRI. pGB2 shows no sequence homology, as detected by DNA-DNA hybridization, to several widely used vectors such as pBR322, pUC8 and phage lambda L47.1. Amongst other applications, DNA fragments can be cloned into the plasmid and then radioactive plasmid DNA can be used as a probe to screen recombinant DNA libraries.

Animals↗

Orotic acid, a new promoter for experimental liver carcinogenesis.

Male Fischer 344 rats initiated with 1,2-dimethylhydrazine 2HCl (100 mg/kg) given 18 hr after partial hepatectomy and exposed to a diet containing 1% orotic acid for 13 months developed a 100% incidence of hepatocellular carcinoma. The creation of nucleotide pool imbalances by dietary orotic acid, for e.g., an increase in uridine nucleotides and a decrease in adenine nucleotides, was considered as a possible mechanism for the promotional effect of orotic acid on liver carcinogenesis. The significance of this hypothesis is that altered nucleotide pools affect both genomic as well as membrane organization. Consistent with this hypothesis is our finding that feeding rats with a diet containing 1% orotic acid for 10 weeks resulted in a liver DNA damage as monitored by its slower sedimentation in alkaline sucrose gradients compared to the corresponding controls. To assess the general applicability of this hypothesis, nucleotide pool imbalances were created by using methods other than feeding orotic acid and their effect on the incidence of gamma-glutamyltransferase positive foci in carcinogen initiated rats was determined. The results obtained indicated that rats initiated with 1,2-dimethylhydrazine.2HCl (100 mg/kg) given 18 hr after partial hepatectomy and exposed to diet deficient in arginine, a regimen that causes an increased synthesis and excretion of orotic acid, or were fed diets containing 1% thymidine or 1% thymine developed greater number of gamma-glutamyltransferase positive foci compared to the corresponding controls fed the basal diets. These results were interpreted to indicate that orotic acid exerts its promotional effect probably by creating an imbalance in nucleotide pools. One of the mechanisms by which an imbalance of nucleotide pools influences the pathogenesis of the carcinogenic process may be by inducing perturbations in the DNA.

1,2-Dimethylhydrazine↗

[Cell kinetic study of human gastric cancers--using an in vitro 3H-thymidine labeling method].

For the purpose of investigating cell the kinetics of human gastric carcinoma, the distribution of 3H-thymidine labeled cells and the labeling index were evaluated in biopsy specimens obtained from 52 patients with gastric cancer, using an in vitro labeling technique. Adenocarcinomas were scattered with labeled cells, while in carcinoid speciners labeled cells were confined to the periphery of tumor cell nests. Characteristically, small-sized cells were exclusively labeled with 3H-thymidine in signet-ring cell carcinomas but signet-ring cells bearing a large amount of mucin were not. Thus signet-ring cells could be regarded as cells in a differentiated condition which have lost their prolife-rating capability. The labeling index of gastric cancers ranged from 10 to 20% in most cases although it varied greatly from case to case (2.2-40.8%). The values of the labeling index were correlated with neither the degree of histological differentiation, macrascopic appearance nor the depth of mural invasion of carcinomas.

Adenocarcinoma↗

Flow cytometric analysis of tumor antigen TA-4 in cervical squamous cells.

Flow cytometric (FCM) analysis of tumor antigen TA-4 was made on cervical cells from 24 patients with squamous cell carcinoma of the uterine cervix and from 22 patients without cancer by using an indirect immunofluorescence staining technique. Cellular TA-4 content was much greater in cancer cells than in non-malignant cells. In all cases of squamous cell carcinoma, FCM histograms showed a broad but conspicuous peak with higher fluorescence intensity, whereas such a fluorescence pattern as seen in malignant cases was not detected in 21 non-malignant subjects whose cells had low levels of the antigen. It would be possible to identify and sort cancer cells on the basis of cellular TA-4 content. Therefore, FCM analysis of TA-4 may provide the basis of a prescreening method for cervical cancer detection.

Adult↗

New embolization method using estrogen: effect of estrogen on microcirculation.

To ascertain the mechanism of action of estrogen administered by a new embolization method, developed by the authors as a treatment method for dural arteriovenous malformations, conjugated estrogens were injected into the mesenteric artery of rabbits, and microcirculatory changes in the dominant areas were studied biomicroscopically. Conjugated estrogen induced sludging and stasis in the microcirculation, approximately in proportion to the concentration and dose.

Animals↗

Hormonal regulation of plasminogen activator mRNA production in porcine kidney cells.

Plasminogen activator (PA) production in LLC-PK1 pig kidney cell culture is induced to high levels by calcitonin and vasopressin, both of which stimulate adenylate cyclase, or by other compounds that also raise intracellular cAMP levels. Enzyme induction is transiently sensitive to inhibition by actinomycin D, suggesting that increased concentrations of cAMP mediate the inducing effects of the hormones by enhancing the transcription of PA-mRNA sequences. We tested this hypothesis by measuring PA-mRNA sequences in the Xenopus oocyte translation system which showed a 15-20-fold enhanced PA-synthesizing capacity when supplied with poly(A)+RNA from induced cells, above that obtained from uninduced cell RNA. Changes in PA-mRNA levels measured by Northern hybridization using cloned PA-specific cDNA gave results that agreed well with those obtained from translation assays. Pretreatment with high concentrations of cycloheximide did not block calcitonin-induced PA-mRNA synthesis, indicating that PA gene activation was a primary transcriptional result of calcitonin stimulation and did not require new protein synthesis.

Animals↗

Redifferentiation as a basis for remodeling of carcinogen-induced hepatocyte nodules to normal appearing liver.

A system is described for the detailed study of the remodeling of hepatic nodules that appear regularly during liver carcinogenesis with chemicals. With the use of the resistant hepatocyte model and by focusing on the caudate lobe, it has been possible to label with [3H]thymidine all the hepatocytes in hepatocyte nodules without any significant degree of labeling of the surrounding hepatocytes. Through such a model, the persistence of the label, in relation to the organization and appearance of the hepatocytes in the nodules, has been followed for 26 weeks. Nodules do not "disappear" to any significant degree by regression or by replacement with hepatocytes from the surrounding liver. Rather, nodule hepatocytes undergo differentiation to an adult liver phenotype. Thus, differentiation ("redifferentiation") of a carcinogen-induced altered hepatocyte population is seen regularly during carcinogenesis despite the irreversible nature of some of the changes induced by a chemical carcinogen during initiation.

2-Acetylaminofluorene↗

Enteric coated polymyxin B in the treatment of hyperammonemia and endotoxemia in liver cirrhosis.

Effects of enteric coated polymyxin B capsules on hyperammonemia and endotoxemia in liver cirrhosis were investigated. Six million units of polymyxin B were orally administered daily to 21 patients with liver cirrhosis and 3 patients with hepatoma cum liver cirrhosis, whose plasma ammonia was higher than normal limit and/or whose plasma endotoxin was positive, for 5-32 days, and serum polymyxin B concentration (in 5 cases), changes of plasma ammonia level (in 19 cases) and plasma endotoxin (in all cases) were observed. Serum polymyxin B concentration was below the detectable limit (0.5 unit/ml) in all cases observed. In the patients with liver cirrhosis, plasma endotoxin and ammonia levels decreased rapidly after polymyxin B treatment, and the decreases in endotoxin levels were kept throughout the treatment. Twelve patients with liver cirrhosis (10 among them were treated with lactulose) were served as controls. All patients who were treated with lactulose alone showed rapid decrease in plasma ammonia, but the decrease in endotoxin in these patients was slower than that in those treated with polymyxin B. From these results, oral administration of polymyxin B is concluded to be useful in the treatment of hyperammonemia and endotoxemia in liver cirrhosis, as a poorly absorbed antibiotic and as an antiendotoxin agent.

Administration, Oral↗

[Aneurysm of anterior communicating artery associated with aortitis syndrome--a treated case by aneurysmal neck clipping (author's transl)].

A rare case of the cerebral aneurysm associated with aortitis syndrome was reported. It seems to be the first case in which neck clipping was successfully performed for aneurysm of the anterior communicating artery. The patient was a 48-year-old female afflicted with pulseless disease. She was admitted to Iwate Central Hospital with severe headache, vomiting and unconsciousness on November 16, 1980. Her radial pulse was faint on the right side. The left carotid angiography revealed an aneurysm in the anterior communicating artery, and neck clipping of the aneurysm was performed 17 days after the onset. The right serial brachiocephalic arteriography revealed occlusion of the right brachiocephalic artery and the right common carotid artery. The serial aortography revealed stenosis of the left common carotid artery and the left vertebral artery. In the literature, 4 cases of those 7 cases associated with aortitis syndrome had aneurysms at the basilar bifurcation or basilar top. It seems to be the reason that the vertebral artery outlasts longer in aortitis syndrome. In our case, we can relate the aneurysmal formation of the anterior communicating artery to the hemodynamic overload of the left A1. General anesthesia in such cases was discussed.

Aortic Arch Syndromes↗