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Biomedical subjects

K Sakaguchi

Publications and source records attributed to K Sakaguchi.

At least 379 records · Page 21Linked to original sources
PubMed1985

Purification and characterization of a DNA polymerase beta from Drosophila*.

A DNA polymerase with properties similar to mammalian polymerase beta has been isolated to near homogeneity from embryos of Drosophila melanogaster. A combination of exclusion chromatography and sodium dodecyl sulfate-gel electrophoresis indicates that this enzyme is composed of a single polypeptide of molecular weight-110,000. Optimum activity on a nicked template occurs at pH 8.4 in the presence of 15 mM MgCl2 and 250 mM NaCl. Enzyme activity is strongly inhibited by dideoxythymidine triphosphate but is relatively insensitive to aphidicolin and N-ethylmalemide. These properties clearly distinguish this enzyme from polymerase alpha, which has previously been characterized from this tissue. This report represents the first extensive purification of a beta-like polymerase from the Protostomic branch of the animal phylogenetic tree. It furthermore generates the potential for a genetic analysis of the function of polymerase beta in DNA recombination, repair, and synthesis.

Animals↗
PubMed1985

Infrared spectra of carbon monoxide complexes of indoleamine 2,3-dioxygenase and L-tryptophan 2,3-dioxygenases. Effects of substrates on the CO-stretching frequencies.

Carbonmonoxy indoleamine 2,3-dioxygenase from rabbit small intestine exhibited two CO stretch bands at 1953 and 1933 cm-1 with half-band widths (delta v 1/2) of both approximately 15 cm-1. Upon addition of an excess amount of L-tryptophan, the substrate, the spectrum changed into that with an intense single band at 1902 cm-1 with the delta v 1/2 of 15 cm-1. Carbonmonoxy L-tryptophan 2,3-dioxygenase of Pseudomonas acidovorans in the absence of L-tryptophan showed a fused CO stretch band which consists of two components at 1965 and 1958 cm-1 (delta v 1/2 for the fused band; 25 cm-1), which was converted into a sharp single band at 1968 cm-1 (delta v 1/2; 10 cm-1) upon addition of excess L-tryptophan. On the other hand, CO complex of rat liver L-tryptophan 2,3-dioxygenase in the absence of L-tryptophan gave a spectrum with a poorly defined peak around 1961 cm-1. By the addition of L-tryptophan, the spectrum changed into that with two distinct bands at 1972 and 1920 cm-1 (delta v 1/2; 6 and 13 cm-1, respectively). These spectra were insensitive to pH in a range where the enzymes were not denatured (neutral to near pH 9). The infrared spectra of the carbonmonoxy enzymes were also affected by the addition of certain effectors such as skatole and alpha-methyl-DL-tryptophan, which facilitate the binding of L-tryptophan to the catalytic site of intestinal and Pseudomonas enzymes, respectively. However, the changes were of different types from those by the saturating amount of L-tryptophan. Possible mechanisms for these phenomena are discussed in relation to the structure of the heme-CO complex in these heme-containing dioxygenases.

Animals↗
PubMed1985

Linear plasmids with terminal inverted repeats obtained from Streptomyces rochei and Kluyveromyces lactis.

Linear plasmids with inverted terminal repeats of 614 bp were obtained from Streptomyces rochei which produced lankacidin. The 5' ends were blocked by the association of a terminal protein. A DNA model of racket frame-like structure is presented implying the juxtaposition of 2 double-stranded DNAs of the same sequence through the binding of cohesive proteins which recognize and bind to the DNA. Two linear plasmids with the inverted terminal repeats of 202 and 184 bp were obtained from a yeast, Kluyveromyces lactis. A killer toxin was produced from the shorter plasmid. The protein toxin inhibited the adenylatecyclase activity of the yeast membrane.

Anti-Bacterial Agents↗
PubMed1985

A colorimetric method for the determination of hydroxamic acid by iodine oxidation.

A new colorimetric method for the determination of hydroxamic acid is described. Hydroxamic acid was oxidized quantitatively by iodine to produce nitrous acid, which was thereafter determined according to the diazocoupling reaction. This method is sensitive to as little as 5 nmol of hydroxamic acid, and the calibration curve is linear up to 50 nmol. Using this method, acyl-CoAs were determined after conversion to hydroxamic acid by the addition of hydroxylamine. The present method is applicable to the determination of free fatty acids which are activated by acyl-CoA synthetase.

Chemical Phenomena↗
PubMed1985

Peripharyngeal space invasion of head and neck cancer--incidence, mechanisms, and management.

We studied the incidence and mode of development of peripharyngeal invasion from head and neck cancers by both retrospective examination of our 127 patients and tracing the dynamics of lymph flow from the hypopharyngeal wall to the peripharyngeal space. We also presented three experiences of the surgical approach to the peripharyngeal invasion by our modification of Attia's technique. Peripharyngeal space invasions occur frequently in a direct or indirect way when meso- or hypopharyngeal or posterior oral cancer invades deeply into the muscle layers and extends to the palatine arch, retromolar region, pharyngoepiglottic fold, pharyngeal tongue, or posterior buccal mucosa. The lymph flow was revealed to move quickly from the lateral hypopharyngeal wall to the base of the skull and occasionally to the opposite side. The peripharyngeal space invasions were successfully removed under a wide surgical field without injuring the important nerves and vessels and with preservation of mandibular function. We should cover all routes for extension of head and neck cancers, including the peripharyngeal space, in the diagnosis and management of these conditions.

Head and Neck Neoplasms↗
PubMed1985

Lactate metabolism in acute myocardial infarction and its relation to regional ventricular performance.

Myocardial metabolism was assessed in 20 patients with acute anterior myocardial infarction using lactate uptake (defined as (aortic lactate - great cardiac venous lactate)/aortic lactate X 100) as an index. The regional ejection fraction of the anterior wall was obtained from left ventriculography. There was a linear relation between lactate uptake and regional ejection fraction (r = 0.79, p less than 0.001). Four patients without total occlusion in the infarct vessel had a higher lactate uptake (19.6 +/- 6.7 versus 4.2 +/- 13.4%, p less than 0.05) and regional ejection fraction (26.3 +/- 7.9 versus 14.9 +/- 7.0%, p less than 0.05) than did 16 patients with total occlusion. The latter group of patients underwent intracoronary infusion of urokinase, which resulted in reperfusion in 13 patients. Lactate uptake before urokinase infusion (sample I), just after reperfusion (sample II), 30 minutes after reperfusion (sample III) and 4 weeks after reperfusion (sample IV) was 5.7 +/- 13.2, -13.9 +/- 14.7, 2.9 +/- 15.2 and 20.2 +/- 11.0%, respectively (sample I versus II and II versus III, p less than 0.01; sample I versus IV and III versus IV, p less than 0.05). The decrease in lactate uptake immediately after reperfusion, which was accompanied by an increase in creatine kinase-MB isoenzyme release into the blood, was considered to be the result of a "washout" effect. Lactate uptake was ameliorated 4 weeks later, accompanied by an improvement (from 15.1 +/- 7.1 to 23.4 +/- 7.2%, p less than 0.01) in the regional ejection fraction. It is concluded that the degree of asynergy was closely related to the extent of metabolic deterioration in myocardial infarction.

Acute Disease↗
PubMed1985

Transfer of DNA killer plasmids from Kluyveromyces lactis to Kluyveromyces fragilis and Candida pseudotropicalis.

Killer plasmids pGKL1 and pGKL2 of double-stranded linear DNAs were transferred from Kluyveromyces lactis to strains of Kluyveromyces fragilis and Candida pseudotropicalis. The resultant killer strains produced 17-fold and 6-fold larger amounts of killer toxin than K. lactis did, respectively. The killer toxin produced by each species appeared to be a glycoprotein.

Bacterial Toxins↗
PubMed1985

Acute myocardial infarction associated with systemic lupus erythematosus documented by coronary arteriograms.

A 19-year-old man with untreated systemic lupus erythematosus had an acute myocardial infarction. A coronary arteriogram five hours after the onset of symptoms revealed total occlusion of the left anterior descending coronary artery. Reperfusion was achieved by coronary thrombolytic therapy with urokinase. Four weeks later, a coronary arteriogram showed only minimal luminal irregularities at the original site of occlusion, where significant reduction in diameter could be induced by ergonovine maleate. This case suggests that coronary arterial involvement in systemic lupus erythematosus may be related to coronary arterial spasm.

Adult↗
PubMed1984

Characterization of a novel killer toxin encoded by a double-stranded linear DNA plasmid of Kluyveromyces lactis.

A novel killer toxin, encoded by a double-stranded linear DNA plasmid pGK l-1 (5.4 MDa) in Kluyveromyces lactis IFO 1267 was purified 320 000-fold from the culture broth of yeast. The toxin was obtained in an electrophoretically homogeneous state with a yield of 24% by hydroxyapatite column chromatography, chromatofocusing and polyacrylamide gel electrophoresis. The purified toxin was dissociated into two subunits with molecular masses of 27 kDa and above 80 kDa, as estimated by Laemmli's sodium dodecylsulfate gel electrophoresis; the exact composition ratio of the two subunits remains unestablished. The isoelectric point was between 4.4 and 4.8. As compared with the reported narrow pH range of action and instability of k1 killer toxin encoded by a double-stranded RNA plasmid of Saccharomyces cerevisiae, the K. Lactis toxin was effective with sensitive strains of S. cerevisiae in a relatively wider pH range between 4 and 8; it was stable for several months at pH 6.0 when stored below -20 degrees C. In contrast to the simple protein nature of the k1 killer toxin with a molecular mass of 11.47 kDa, the K. lactis toxin maintained a mannoprotein nature, as it was absorbed by a ConA-Sepharose column and eluted by methyl alpha-D-mannoside. The growth inhibitory activity of K. lactis toxin was enhanced 2-35-fold by the presence of 4-60% glycerol.

Ascomycota↗
PubMed1984

[Urinary phosphate and cyclic adenosine monophosphate response to intravenous administration of synthetic human parathyroid hormone-(1-34) in idiopathic hypoparathyroidism, pseudohypoparathyroidism, pseudopseudohypoparathyroidism and normal subjects].

The response to exogenous parathyroid hormone (PTH) with urinary excretion of phosphate and cyclic adenosine monophosphate (cAMP) was tested by the use of synthetic human parathyroid hormone (1-34) [hPTH-(1-34)] on 59 patients with hypocalcemia and normal or high serum inorganic phosphorus and normal renal function without a history of parathyroidectomy for differentiation between idiopathic hypoparathyroidism (IHP), pseudohypoparathyroidism (PHP) and related diseases along with 18 normal subjects. A positive phosphaturic response to exogenous PTH was defined as the increment of 2 hours phosphate excretion (delta P) of more than 35 mg. A positive urinary cAMP response to exogenous PTH was defined as the increment by more than 1 mumole per one hour (delta cAMP) and the increase of 1 hour excretion by more than 10 times. Increments of 2 hours urinary phosphate excretion in response to hPTH-(1-34) 100 units were 60.5 +/- 7.7 mg (mean +/- SEM) in 27 patients with IHP, 23.5 +/- 5.9 mg in 21 patients with PHP type I and 24.9 +/- 4.0 mg in 17 normal subjects. Increments of 1 hour urinary cAMP excretion in response to hPTH-(1-34) 100 units were 12.0 +/- 1.5 mumole in 27 patients with IHP, 0.33 +/- 0.10 mumole in patients with PHP type I and 23.6 +/- 5.8 mumole in 15 normal subjects. Ratios of 1 hour urinary cAMP excretion were 97 +/- 10 in 27 patients with IHP, 3.6 +/- 0.5 in 21 patients with PHP type I and 54 +/- 14 in 15 normal subjects. Positive phosphaturic and negative urinary cAMP response was encountered in 3 out of 21 patients with PHP type I in response to hPTH-(1-34). This exaggerated phosphaturic response should be considered as due to the influence of treatment with Ca or vitamin D derivatives.

Adolescent↗
PubMed1984

A linear DNA plasmid from Streptomyces rochei with an inverted terminal repetition of 614 base pairs.

The terminal structure of a linear plasmid pSLA2 , which was isolated from Streptomyces rochei , was analysed. The 5' ends of pSLA2 DNA were blocked by the association of a protein probably covalently bonded with the DNA. This block is removed by alkali treatment and blunt ends with 5'-phosphate and 3'-hydroxy termini were released. The two terminal fragments of pSLA2 were cloned and the nucleotide sequence was determined. An inverted terminal repetition of 614 bp was found along with the presence of further interrupted homologous sequences beyond this area up to 800 bp. These are the first inverted terminal repeat sequences found in microbial linear plasmids.

Base Composition↗