Biomedical subjects
T Takano
Publications and source records attributed to T Takano.
[Two cases of rupture of intraaortic balloon].
We reported two cases of rupture of intraaortic balloon (IAB). The most likely cause appears to be the rupture of IAB membrane against a calcific atherosclerotic aortic plaque. When the IAB ruptures by contact of calcific lesions in aorta, the leak detection of device of intraaortic balloon pumping is useless to diagnose this rupture. Therefore, the rupture of IAB through a pin hole is diagnosed by the transient presence of blood in the tube connecting the balloon. It is recommended that the balloon immediately should be removed at the transient presence of blood in the connecting tube.
[Two cases of M. avium complex infection presenting as solitary pulmonary nodule].
Case 1 was a 75-year-old woman. Her chest X-ray showed a 3 cm solitary nodule in the right S4, and biopsy obtained by fiberoptic bronchoscopy revealed epithelioid cell granuloma. Four weeks later, Mycobacterium avium complex (MAC) was detected on culture of the bronchial lavage fluid. She was treated with INH, RFP and EB for 12 months and recovered with no relapse. Case 2 was a 75-year-old man with mild diabetes mellitus and hypertension. Chest X-ray showed a 4 cm solitary nodule in the right S9. Percutaneous pulmonary aspiration revealed numerous acid-fast bacilli on smear, and he was treated with INH, RFP and EB. Culture proved M. avium complex. The patient was unable to continue his medications because of gastrointestinal side effects, so right lower lobectomy was performed. Cases of M. avium complex infection presenting as solitary pulmonary nodule are very rare. We found only 12 reported cases in Japan and in other countries. The most usual site of cavitary lesions in M. avium complex infections is both upper lobes, in contrast to the relatively even distribution of solitary pulmonary nodules of the 14 cases (12 reported cases and our 2 cases).
[A successful surgical repair for all right pulmonary venous return and intact atrial septum associated with patent left superior vena cava].
A successful repair of total right pulmonary venous return and intact atrial septum associated with patent left superior vena cava (PLSVC) is reported. A 31-year-old women was admitted for evaluation of heart failure. A heart murmur had been detected since her childhood without any subjective symptoms. She was diagnosed as partial anomalous venous return of all right pulmonary vein and intact atrial septum (IAS) associated with PLSVC by cardiac catheterization. Operative findings revealed that all right pulmonary vein connected to right atrium (RA) and superior vena cava (SVC), PLSVC drained into coronary sinous (CS), therefore RA, right ventricle and CS were enlarged, but SVC was small due to PLSVC. Through large incision from RA to SVC, atrial septum was opened 30 mm in diameter. Internal conduit using pericardial patch was made in order to drain anomalous pulmonary venous blood into left atrium through the ASD. Finally, SVC and RA were reconstructed by pericardial patch for prevention of conduit obstruction. One month after operation, no stenosis of SVC and right pulmonary vein was evidenced by cardiac catheterization and all through the postoperative course, arrhythmias did not detected. She was discharged with uneventful postoperative course.
[Application of cyclosporin for cornea graft].
This study aimed to determine the optimal concentration rate of clinically effective Cyclosporin (CYA). Exchange penetrating keratoplasties were performed on 30 albino rabbits divided into 3 groups of ten, Groups I, II, and III, using 7 mm. trephine. In Group I 0.025% CYA drops were administered 4 times per day for 50 days and similarly 0.05% CYA drops were given in Group II. Only the solvent (alpha cyclodextrin), without any CYA, was applied to Group III, the control group, in the same manner. Suture removal and skin grafting were carried out on the 14th day after operation, as an additional means of sensitization. The 50-day post-operative rate of transparency retention was 40% for Group I, and 80% for Group II, and 20% for Group III, indicating that 0.05% CYA concentration was the most effective. In Experiment II, hetero-lamellar keratoplasties were performed on 16 albino rabbits to 8 Wistar rats, divided into Groups I and II. CYA (0.05% concentration) was applied 4 times a day for 50 days in Group I. Group II, the control group, was not treated. Both groups were followed for 100 days post operation. The 50-day post-operative rate of transparency retention of Group I was 71.4% and 12.5% for Group II. These figures also confirmed the effectiveness of 0.05% CYA. The results of our two experiments demonstrate that the application of 0.05% CYA would be most effective clinically.
Abrogation of p53-mediated transactivation by SV40 large T antigen.
p53 is known to bind specifically to the 44-bp human DNA sequence in an immunoprecipitation assay. We show here that the transcription of the reporter CAT gene linked with the herpesvirus thymidine kinase (tk) promoter containing the 44-base sequence is enhanced by mouse wild-type but not mutant-type p53 in F9 and p53-null Saos-2 cells. The p53-mediated transactivation was dramatically abrogated by introduction of SV40 large T antigen (SVLT) in Saos-2 cells in which p53 was clearly associated with SVLT. Furthermore, the p53-SVLT complex did not bind to the 44-base sequence at all. Thus, SVLT sequesters the transactivation function of the wild-type p53 by inhibiting the binding of p53 to the 44-base sequence. This is good evidence to show 'loss of functions' in the product of a tumor-suppressor oncogene by a dominant oncogene product at a molecular level.
Loss of collagenase gene expression in immortalized clones of SV40 T antigen-transformed human diploid fibroblasts.
We isolated a cDNA clone whose expression was lost during immortalization. The subtractive hybridization was performed between a genetically matched pair of mortal and immortal lines of SV40 T antigen-transformed MRC-5. The clone was found to code human interstitial collagenase. The expression of collagenase gene was almost completely shut off in seven out of eight independent immortalized clones. In addition, the levels of collagenase expression were dramatically increased toward crisis in the T antigen-transformed but mortal cells. These findings suggest the possibility that the regulatory mechanism of collagenase expression is related to both processes of in vitro aging and immortalization.
Four synonymous genes encode calmodulin in the teleost fish, medaka (Oryzias latipes): conservation of the multigene one-protein principle.
We cloned four distinct calmodulin (CaM)-encoding cDNAs from a small teleost fish, medaka (Oryzias latipes). The deduced amino acid (aa) sequences were exactly the same in these four genes and identical to the aa sequence of mammalian CaM, because of synonymous codon usages. The four cDNAs from medaka, termed CaM-A, -B, -C and -D, corresponded to mRNAs of 1.8, 1.4, 2.5 and 1.8 kb, respectively, in Northern blot analysis. Our results demonstrated that the 'multigene one-protein' principle of CaM synthesis is applicable to medaka, as well as to mammals whose CaM is encoded by at least three different genes.
Expression of platelet activating factor receptor in renal tubular cell line (LLC-PK1).
Northern blot analyses of poly(A)+ RNA extracted from cloned renal tubule cells, LLC-PK1, MDCK and JTC-12 cells, were performed using an isolated cDNA of guinea pig platelet activating factor (PAF) receptor as a probe. The results showed the expression of single entity of PAF receptor mRNA in LLC-PK1, but not in MDCK or JTC-12 cells. PAF also induced a dose-dependent elevation of intracellular calcium in LLC-PK1 cells as assessed by Fura-2 fluorescence signals, which was completely blocked by a PAF receptor antagonist, WEB 2170. These results indicate a PAF receptor-effector system in a renal tubular cell line LLC-PK1, providing a possible model system for studying physiological roles of PAF receptors in renal tubules.
[Progress on diagnosis of severity of myocardial infarction].
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Intercellular transport through a partially denuded arterial endothelial monolayer. Effect of platelets and PGI2.
Fluorescein Dextran (FD) was shown to be transported at increased rates through partially denuded endothelial monolayer. Platelet binding to the partially denuded monolayer lowered transport rates to those comparable with intact endothelium. Inhibition of transport by platelet binding was not affected by the addition of isocarbacyclin (a stable derivative of PGI2). This result suggests that adherent platelets at the partial denudation site are sufficient to suppress transport of FD.
Suramin prevents import of acyl-CoA oxidase into rat liver peroxisomes.
The inhibitory effect of suramin on the import of [35S]acyl-CoA oxidase into purified rat liver peroxisomes was investigated in vitro. The import of acyl-CoA oxidase was inhibited completely by 10 microM suramin, whilst the latency of catalase remained unchanged. The important value decreased 60% by pretreatment of peroxisomes with 10 microM suramin, but it did not decrease by pretreatment of translation products. Polysulfonate compounds which have two clusters of negative charges, such as Cibacron blue F3GA and Trypan blue, as well as suramin, inhibited the import, whilst mono- and disulfonate compounds did not.
Genetics of neurofibromatosis 1 in Japan: mutation rate and paternal age effect.
We have performed formal genetic studies on 26 patients (14 males, 12 females) with neurofibromatosis 1 (von Recklinghausen's disease, NF1) in Japan. Family studies of 74 members of 18 kindreds revealed that 50% of the cases were caused by a new mutation; the mutation rate was assumed to be 7.3-10.5 x 10(-5). A tendency of paternal age effect, which was not accounted for by the maternal age effect, was observed, but live-birth order had no significant effect. Genetic linkage of neurofibromatosis 1 to the NF1 gene or the genetic marker in the pericentric region of chromosome 17 was established in 3 informative families.
Properties of the enzyme expressed by the Pseudomonas saccharophila maltotetraohydrolase gene (mta) in Escherichia coli.
The maltotetraohydrolase gene (mta) from Pseudomonas saccharophila was expressed in Escherichia coli JM109. Maltotetraohydrolase was produced mostly (approximately 90%) in the periplasmic space. The amino-terminal amino acid sequence and molecular weight of the recombinant enzyme were identical with those of the native enzyme, and there was no significant difference in the substrate specificity and modes of action. This system for maltotetraohydrolase expression is useful for studies of the structure and function of the enzyme.
V1-receptor mediated GSH efflux by vasopressin from rat hepatocytes.
Vasopression increases sinusoidal efflux of GSH in the perfused rat liver. The mechanism of this effect was studied in the perfused rat liver and in isolated rat hepatocytes. Vasopressin stimulated GSH efflux in both systems and a V1-receptor antagonist (OPC-21268) significantly inhibited the effect of vasopressin suggesting that vasopressin stimulates GSH efflux from rat hepatocytes via V1-receptor.
Possible involvement of protein kinase C and calcium in GSH efflux from Hep G2 cells.
We investigated the effects of protein kinase C modulations and calcium mobilization on GSH efflux in Hep G2 cells. GSH efflux from Hep G2 cells was increased by a phorbol ester. Staurosporine, an inhibitor of protein kinase C, diminished phorbol ester-stimulated GSH efflux from the cells. GSH efflux was negatively correlated with extracellular calcium concentrations. Verapamil enhanced GSH efflux, whereas ATP decreased GSH efflux. The latter effect was diminished in the absence of extracellular calcium. Protein kinase C and calcium mobilization may be crucial factors in GSH efflux from human hepatocytes.
Induction and characterization of two types of ATPase on rat liver peroxisomes.
Clofibrate increased oligomycin-resistant ATPase activity in peroxisomes more than 17-fold (5.15 +/- 0.71 milliunits/mg protein) in rat liver. The activity was dependent on divalent cations (Mg2+ > Ca2+) with an optimum pH of 7.5. This activity was partially inhibited by N-ethylmaleimide (NEM), 4,4'-dithiocyanatostilbene-2,2'-disulfonic acid (DIDS), silicotungstic acid (STA), and high concentrations of N,N'-dicyclohexylcarbodiimide (DCCD). Proteinase K digestion of intact peroxisomes severely reduced the NEM-sensitive activity, but little affected the NEM-resistant activity. NEM-sensitive and -resistant ATPases showed Km values for ATP of 780 and 73 microM, respectively. The NEM-sensitive activity was inhibited completely by DIDS, 7-chloro-4- nitrobenzo-2-oxa-1,3-diazole (NBD-Cl), tributyltin chloride (TBT), and quercetin, and partially by DCCD and STA, whereas the NEM-resistant activity was totally insensitive to these chemicals except for STA. These activities had unique requirements for divalent cations, anions, and substrates, respectively. They were partially separated by gel filtration chromatography and had molecular masses of 520 kDa (NEM-sensitive enzyme) and 450 kDa (NEM-resistant enzyme), respectively.
Major ATPases on clofibrate-induced rat liver peroxisomes are not associated with 70 kDa peroxisomal membrane protein (PMP70).
We previously reported that novel Mg(2+)-ATPases were induced in rat liver peroxisomes by clofibrate administration and that these activities consisted of at least two types of enzymes, N-ethylmaleimide (NEM)-sensitive and -resistant. Here we present evidence that neither of these major peroxisomal ATPases is associated with the 70-kDa peroxisomal membrane protein (PMP70), because: (i) proteinase K treatment of peroxisomes resulted in inactivation of only NEM-sensitive ATPase, whereas disappeared PMP70 completely; (ii) NEM-sensitive ATPase activity was barely immunoprecipitated with anti-PMP70 IgG; (iii) the solubilized ATPases behaved differently from PMP70 on native PAGE; and finally (iv), the major peroxisomal ATPases were separated from PMP70 on gel filtration chromatography.