Search PubMed⌕ Search

Biomedical subjects

T Sano

Publications and source records attributed to T Sano.

At least 775 records · Page 43Linked to original sources
PubMed1981

Increased synthesis of hexacosanoic acid (C23:0) by cultured skin fibroblasts from patients with adrenoleukodystrophy (ALD) and adrenomyeloneuropathy (AMN).

We studied the metabolism of radioactive stearic acid by cultured skin fibroblasts from patients wtih adrenoleukodystrophy (ALD) and its variant, adrenomyeloneuropathy (AMN), to clarify the mechanism of the increased content of very long chain saturated fatty acids in cholesterol esters and sphingolipids, which are known to be the characteristic biochemical changes in ALD and AMN. A substantial amount of hexacosanoic acid (C26 : 0) wa synthesized from stearic acid by ALD and AMN fibroblasts, whereas only a trace amount of hexacosanoic acid was synthesized by control fibroblasts. This indicates that the primary biochemical defect in ALD and AMN may involved the elongation system of very long chain fatty acids.

Adrenal Gland Diseases↗
PubMed1981

Regio-selective 10-hydroxylation of patchoulol, a sesquiterpene, by pithomyces species.

Of some 350 microorganisms screened, four strains of Pithomyces species were found to carry out regio-selective hydroxylation of patchoulol, a sesquiterpene, to 10-hydroxypatchoulol: Pithomyces sp. NRJ201, P. chartarum NRJ210, and, to a lesser extent, P. cynodontis ATCC 26150 and P. atro-olivaceus IFO 6651 were found to catalyze this reaction. A method has been developed by which 10-hydroxypatchoulol was obtained in 25 to 45% yields in 1- to 5-liter fermentation jars at 2 to 4 g of patchoulol per liter and isolated as pure material in 30% yields.

Journal Article↗
PubMed1981

Oscillatory afterpotentials in dog ventricular muscle fibers.

Ventricular muscle fibers from dog hearts were superfused with K+-free, high Ca2+ solutions after exposure to a K+-free, Ca2+-free superfusate. Following a series of driven action potentials, oscillatory after potentials (OAPs) were elicited in all 40 preparations at a resting potential of greater than -60 mV. The OAPs appeared not to represent either an electrotonic influence from Purkinje fibers or reentry. They showed a non-monotonic dependence on the basic cycle length, as well as on the number of preceding action potentials. When the OAPs attained threshold, there was extra-excitation (triggered activity) and, occasionally, sustained rhythmic activity. Single premature impulses increased the amplitude of the OAPs, but single or multiple stimuli applied during sustained rhythmic activity failed to stop it. The amplitude of the OAPs increased with higher external [Ca2+] and with lower external [Na+]. The OAPs and triggered activity were suppressed in the presence of Mn2+, verapamil, and 2.7 mM K+. Our results indicate that OAPs and triggered activity can be evoked in the working myocardium at normal resting potentials under various conditions, and that they represent abnormal impulse formation rather than reentry.

Action Potentials↗
PubMed1981

Molecular heterogeneity and biological activity of immunoreactive somatostatin in medullary carcinoma of the thyroid.

Two cases of somatostatin (SRIF)-producing medullary carcinoma of the thyroid are presented. The plasma levels of SRIF and calcitonin changed in accordance with the clinical course before and after resection of the tumor. On chromatographic analysis of tumor extracts derived from primary and metastatic tumors of medullary thyroid carcinoma, at least two components of immunoreactive SRIF (IR-SRIF) of large molecular size were found, besides a component corresponding to the tetradecapeptide (SRIF 14); one of these seemed to have almost the same molecular weight as the octacosapeptide (SRIF 28). Most of the IR-SRIF in one patient's plasma was eluted in the same position as tetradecapeptide SRIF. The biological activity of SRIF recovered from the tumor extract was assessed by measuring activity for inhibiting GH release using dispersed rat anterior pituitary cells. GH release from the cells into the incubation medium tended to decrease at a concentration of 1 x 10(-9) M IR-SRIF derived from the tumor (3000 +/- 482 ng/10(5) cells . 3 h) compared with the control value (4288 +/- 567 ng/10(5) cells . 3 h). A significant decrease was observed at concentrations of 1 x 10(-8) M (1880 +/- 403 ng/10(5) cells . 3 h) and 5 x 10(-8) M (938 +/- 262 ng/10(5) cells . 3 h). Responses to equivalent amounts of synthetic SRIF 14 were similar. This suggests that IR-SRIF in the tumor has almost the same biological activity as synthetic tetradecapeptide SRIF.

Adult↗
PubMed1981

Potentiation of natural killer activity of human lymphocytes by Staphylococcus aureus bacteria and its protein A.

Cytotoxic activity of human lymphocytes against the myeloid cell line K-562 was augmented greatly by 24-h incubation with Staphylococcus aureus Cowan I bacteria (SpA CoI) and its protein A. This effect was not observed when these stimulants were added after preincubation, suggesting that this activity was different from so-called lectin-induced cellular cytotoxicity. Potentiation required at least 12 to 18 h incubation of lymphocytes with these stimulants. Macrophage depletion did not affect the potentiation by protein A or SpA coI, although the potentiation by poly I:C or OK-432, an immunopotentiator of Streptococcus pyogenes was completely reduced. Further cell separation procedures revealed that neither T cells nor FcR- cells, which showed little natural killer (NK) activity, were enhanced by protein A or SpA coI. On the other hand, (a) null cells which were obtained from nylon column (NC)-passed fraction by depleting T cells and surface membrane Ig-positive cells, and (b) FcR+ E- cells which were obtained from NC-passed fraction by depleting FcR- cells and T cells, showed marked NK activity by themselves and were further augmented by these stimulants. FcR+ E+ cells failed to show NK activity even if they were stimulated by these stimulants. Thus, it was found that protein A and SpA CoI, as well as human interferon, could stimulate NC-non-adherent, FcR+, E- NK cells and potentiate markedly their NK activity.

Adjuvants, Immunologic↗
PubMed1980

Platelet release reaction in vivo in patients with ischaemic heart disease after isometric exercise and its prevention with dipyridamole.

In 20 patients with ischaemic heart disease (IHD), platelet sensitivity to ADP-aggregation, plasma von Willebrand factor (vWF) and plasma beta-thromoboglobulin (beta-TG) were measured before and after isometric exercise. Effect of dipyridamole on these determinants was studied in a crossover fashion. To assess plasma vWF level, a new simple method was employed which has the advantage of not requiring an optical aggregometer and was proved to be reproducible. No significant difference was seen in platelet sensitivity to ADP-aggregation, vWF and beta-TG among healthy controls, IHD patients on placebo and on dipyridamole at rest. After exercise, platelet sensitivity to aggregation, plasma vWF and beta-TG increased significantly in IHD patients on placebo. In healthy controls, no significant changes were seen. On dipyridamole, above changes seen in IHD patients were not seen. The results suggests that isometric exercise may induce platelet release reaction in vivo and may produce hypercoagulable state in IHD patients. These phenomena may be prevented by pretreatment with dipyridamole.

Adult↗
PubMed1980

Kinetics of helix-coil transition of polypeptides in solution by the relaxation methods.

Relaxation phenomena were studied in aqueous solutions of poly (alpha-L-glutamic acid) (Glu)n and poly (alpha-L-lysine) (Lys)n under various conditions using the electric field pulse method with detection by conductivity change. The relaxation time for the (Glu)n has a maximum value at the midpoint of the helix-coil transition. Some possible mechanisms are discussed and the observed relaxation phenomenon is attributed to the helix-coil transition. In the case of (Lys)n, the relaxation time as a function of pH exhibits two maxima. One is assigned to a proton transfer reaction and the other to the helix-coil transition. Using the Schwarz's theory the rate constants of the helix growth step for both (Glu)n and (Lys)n are estimated. The difference in the activation parameters for (Glu)n and (Lys)n is discussed.

Journal Article↗
PubMed1980

Properties of the fibers in the pathways along the anterior and posterior portions of the left A-V ring.

A comparison was made of the electrophysiological properties of the fibers between the previously reported conduction pathways from the left atrium to the right atrium and to the ventricle (left A-V ring pathways) and the ordinary atrial muscle, using perfused isolated rabbit hearts. Each fiber within these pathways showed action potential with a well-developed plateau phase. The plateau phase of these action potentials was distinctly shortened by an infusion of 1 x 10-6 g/ml of acetylcholine. When the heart was perfused by Tyrode solution with 15 mM KCl, the trans-membrane potential of the ordinary atrial muscle fiber showed a decrease of resting potential and of amplitude of action potential. The fibers within these pathways, however, were more resistant to the high potassium solution than the ordinary atrial fibers. A slow diastolic depolarization was observed in the fibers of the pathway when 1-isoproterenol (1 x 10-5 g/ml) was applied locally. These findings suggest that the fibers within the left A-B ring pathways possess similar electrophysiological properties to the specialized fibers in the atria.

Acetylcholine↗
PubMed1980

Hepatitis B e antigen polypeptides isolated from sera of individuals infected with hepatitis B virus: comparison with HBeAg polypeptide derived from Dane particles.

Hepatitis B e antigen (HBeAg) occurs in the serum of individuals infected with hepatitis B virus both free and in association with IgG. Utilizing a succession of steps involving salt precipitation, affinity chromatography, ion-exchange chromatography and isoelectrofocusing, we isolated free and IgG-bound forms of HBeAg from the sera of infected individuals with an overall gain in specific activity of 3000-fold and 540-fold, respectively. Polypeptide profiles of purified HBeAg preparations were studied by SDS-polyacrylamide gel electrophoresis in the presence of 2-mercaptoethanol. Both free and IgG-bound preparations revealed polypeptides with mol. wt. of 15500 (P15.5) and 16 500 (P16.5), and HBeAg activity was detected corresponding to their positions. The HBeAg polypeptides (P15.5/16.5) derived from sera were physicochemically different from the two polypeptides with HBeAg activity (P19 and P45) liberated from Dane particle cores by the conventional method involving incubation with Nonidet P40 and 2-mercaptoethanol. However, when core particles were prepared in the presence of a proteolytic enzyme, in addition to Nonidet P40 and 2-mercaptoethanol, they gave rise to HBeAg polypeptides with mol. wt. of 31000 (P31) and 15 500. Furthermore, P31 split into P15.5 when heated at 100 degrees C for 2 min. On the basis of these results, P15.5 may be assumed to be the essential polypeptide bearing HBeAg activity in the serum and also in Dane particles.

Hepatitis B↗
PubMed1980

Impulses of S-A block area.

Micro-electrode studies in 13 excised rabbit preparations were done to determine the site of S-A block. Previously the fastest S-A conduction occurred in the area connecting the sinus node and the right branch of the crista terminalis. When a small cut was made in this area, 5 of the 13 hearts showed the first degree S-A block. Two hearts exhibited the second degree S-A block of the Wenckebach phenomenon and 3 showed the third degree block after cutting the same area. All blocks were transient and, within 1 hour after cutting, they were of the first degree. When the caval area was subsequently cut in these 10 hearts, all of them developed the complete S-A block. Three other hearts showed the complete S-A block by cutting only the connectable area of the sinus node with the right branch of the crista terminalis. The first cutting of the caval area surrounding the sinus node excepting the above mentioned connection did not change the S-A conduction time. Conclusions from these experiments reveal that the dominant sino-atrial conduction occurs through the connectable area of the sinus node with the right branch of the crista terminalis. Functional impairment to this region is essential and necessary to the development of any degree of S-A block.

Animals↗