Biomedical subjects
Publications and source records attributed to A Naito.
Streptomyces showdoensis SANK 65080 produced terferol, an inhibitor of cyclic adenosine 3',5'-monophosphate phosphodiesterase (cAMP-PDE). NMR spectrometry and X-ray analysis were used to determine the structure of the compound, a new member of the terphenyl family.
Terferol, a new inhibitor of cyclic adenosine 3',5'-monophosphate phosphodiesterase (EC 3.1.4.17, cAMP-PDE), was isolated from the cultured broth of Streptomyces showdoensis SANK 65080. It was found to have the molecular formula C19H16O3 and to possess inhibitory activity not only against cAMP-PDE but also against cyclic guanosine 3',5'-monophosphate phosphodiesterase (cGMP-PDE) from various rat tissues. The terferol concentration required for 50% inhibition of cAMP-PDE was 0.82 microM.
A 46-year-old woman visited our outpatient clinic complaining of dull right hypochondrial pain. Ultrasonography revealed four cysts in the right lobe of the liver. Arteriography and CT could not determine whether these cysts were benign or malignant. Because one of these cysts contained chocolate-colored fluid, amebic abscess was suspected, and the cyst was drained. No amebae were found in the cultured exudate, and fresh bleeding continued; therefore, laparotomy was performed. A tumor was present on the surface of the liver. Right lobectomy was performed. The resected specimen contained one nonepithelialized cyst which was invaded by surrounding cholangiocellular carcinoma and three epithelialized cysts. Preoperative diagnosis of this kind of cholangiocellular carcinoma seems to be very difficult. Recently cholangiocellular carcinoma associated with developmental cysts has been classified as a new entity different from cystadenocarcinoma. Cholangiocarcinoma, which belongs to this group, seems to deserve special attention.
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A 28-year-old woman with primary ovarian carcinoma which was found with intracranial metastasis is reported. The patient was operated on because of metastatic brain tumor with unknown primary lesion. Subsequently, left ovarian tumor was found, and left salpingo-oophorectomy was performed. The histological diagnosis was endometrioid carcinoma. A review of the literature shows that intracranial metastasis by ovarian carcinoma is very rare. The incidence is lower than 2.1%. The present case in which intracranial metastasis manifested itself before primary ovarian carcinoma seems to be extremely rare.
Mitral valve prolapse (MVP) is frequently observed in patients with low body weight and/or skeletal abnormalities such as pectus excavatum and straight spines. There may be a variety of associated autonomic dysfunctions. Whether MVP is a complication of anorexia nervosa which has similar clinical features, including weight loss, skeletal abnormalities and autonomic dysfunctions, has not been reported. The present study was an investigation of the incidence of MVP and cardiac function in anorexia nervosa by echocardiography. Two-dimensional and M-mode echocardiography, and systolic time intervals were evaluated for 19 women with anorexia nervosa, from 13 to 25 years of age and having a mean age of 18.2 years. Their body weights ranged from 23.9 to 43 kg with a mean of 33.5 kg, and were at least 25% less than their ideal body weights (ranges were from 25 to 52%). The same studies were performed for 19 women with MVP diagnosed echocardiographically and without anorexia nervosa as controls. Their ages ranged from 14 to 26 years. Results were as follows: MVP was observed in 74% of patients with anorexia nervosa. The mean heart rates were 51.7 and 70.5/min in the anorexia nervosa and control groups, respectively. A significant difference (p less than 0.001) was observed between the two groups. The mean heart rate of patients with anorexia nervosa having MVP of both leaflets and no MVP were 45.8 and 59.0/min, respectively. The difference between these two sub-groups was statistically significant (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
A 3.1-kilobase Bgl II fragment of Saccharomyces cerevisiae carrying the nuclear gene encoding the mitochondrial polypeptide chain elongation factor (EF) Tu has been cloned on pBR327 to yield a chimeric plasmid pYYB. The identification of the gene designated as tufM was based on the cross-hybridization with the Escherichia coli tufB gene, under low stringency conditions. The complete nucleotide sequence of the yeast tufM gene was established together with its 5'- and 3'-flanking regions. The sequence contained 1,311 nucleotides coding for a protein of 437 amino acids with a calculated Mr of 47,980. The nucleotide sequence and the deduced amino acid sequence of tufM were 60% and 66% homologous, respectively, to the corresponding sequences of E. coli tufA, when aligned to obtain the maximal homology. Plasmid YRpYB was then constructed by cloning the 2.5-kilobase EcoRI fragment of pYYB carrying tufM into a yeast cloning vector YRp-7. A mRNA hybridizable with tufM was isolated from the total mRNA of S. cerevisiae D13-1A transformed with YRpYB and translated in the reticulocyte lysate. The mRNA could direct the synthesis of a protein with Mr 48,000, which was immunoprecipitated with an anti-E. coli EF-Tu antibody but not with an antibody against yeast cytoplasmic EF-1 alpha. The results indicate that the tufM gene is a nuclear gene coding for the yeast mitochondrial EF-Tu.
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We have developed a cell-free system from Escherichia coli for studying illegitimate recombination between nonhomologous DNA molecules. The recombination is stimulated by oxolinic acid, an inhibitor of DNA gyrase. The stimulation is abolished by coumermycin A1 and is not found in extracts of nalidixic acid-resistant (gyrA) mutants. We therefore inferred that DNA gyrase directly participates in illegitimate recombination, at least in the presence of oxolinic acid [Ikeda, H., Moriya, K. & Matsumoto, T. (1981) Cold Spring Harbor Symp. Quant. Biol. 45, 399--408]. The structure of recombinant DNA molecules formed in the presence of oxolinic acid from a cross between phage lambda and plasmid pBR322 DNAs was analyzed by heteroduplex mapping. Among nine isolates tested, two recombinants were formed by the insertion of the plasmid into the lambda genome. The seven other recombinants had more complicated genome structures. Insertion of pBR322 was accompanied by a deletion on one of the genomes. In all cases, the end points of deletions coincided with one end of the pBR322 insertion. Recombination sites seemed to be distributed randomly on the lambda and pBR322 genomes. Analysis of nucleotide sequences of the recombination junctions proved that the crossover took place between nonhomologous DNA sequences. A model for DNA gyrase-mediated illegitimate recombination is discussed.
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D-Amino acid oxidase (EC 1.4.3.3) systems from Trigonopsis variabilis SANK 59963 were found to catalyze cephamycin C. The reaction products were assigned to 7 beta-(5-carboxy-5-oxovalerylamido)-7 alpha-methoxy-3-carbamoyl-3-cephem-4-carboxylic acid, and 7 beta-(4-carboxy-butyrylamido)-7 alpha-methoxy-3-carbamoyl-3-cephem-4-carboxylic acid, respectively. D-Amino acid oxidase from hog kidney was not able to catalyze cephamycin C.
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Pepsin was spin-labelled with N-(1-oxyl-2,2,6,6-tetramethyl-4-piperidyl) bromoacetamide, possibly at the active site, at a beta-catboxyl group of a reactive aspartic acid. The spectrum of the spin-labelled pepsin showed that the spin probe was strongly immobilized (correlation time is greater than or equal to 10(-8) sec). Spin-labelled pepsin was thermally denatured at various temperatures and electron paramagnetic resonance (e.p.r.) spectra were taken at various times. Rates of denaturation estimated from the e.p.r. spectra at various temperatures showed that the enthalpy and entropy of thermal denaturation of spin-labelled pepsin at pH 3.5 were 48.0+/-4.9 kcal/mole and 214.7+/-14.5 e.u. respectively. Addition of conc. NaOH or 1 M acetate buffer at pH 6.0 sharpened e.p.r. spectra of the spin-labelled pepsin, indicating that the spin probe became mobilized by alkaline denaturation. Addition of urea caused unfolding of the protein which increased with the urea concentration, although only slight transition of conformational changes was observed in the e.p.r. spectra.
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