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H Sugihara

Publications and source records attributed to H Sugihara.

At least 343 records · Page 19Linked to original sources
PubMed1989

[An attempt of thallium-201 myocardial perfusion imaging during transient coronary arterial occlusion by PTCA].

To evaluate the myocardial perfusion during transient coronary occlusion, we attempted to obtain the myocardial scintigraphy during percutaneous transluminal coronary angioplasty (PTCA). Tl-201 was injected at the last inflation of angioplastic balloon and occlusion was kept on for 60 sec. Planar images or SPECT were obtained immediately after PTCA. With this protocol, myocardial perfusion defects were observed during PTCA and fully redistributed 3 hours after Tl injection. Extent of ischemic lesions were almost same as that observed during exercise in two cases without collateral vessels. In a case with well visualized collateral vessels, perfusion defect was smaller in PTCA images than that in exercise stressed images. We conclude that intravenous injection of Tl-201 during PTCA is useful to assess the alteration of myocardial perfusion due to transient coronary occlusion without increasing the risk of angioplastic procedure.

Adult↗
PubMed1989

[Evaluation of transient dilation of the left ventricle on exercise thallium-201 scintigraphy].

We have noted that some patients with ischemic heart disease have a pattern of transient dilation of the left ventricle on the immediate post exercise images as compared with 3 hour redistribution images. We assessed correlation between transient dilation of the left ventricle and coronary arteriographic findings in 32 patients with ischemic heart disease and 15 controls. Initial and delayed conventional short axis tomographic images were obtained after reconstruction of 20 projections acquired over 180 degrees. Thirty six radii by every 10 degrees were generated from the center of the middle myocardial images of the short axis. An area surrounded by thirty six points of maximal count on each radius was calculated in initial and delayed images. Transient Dilation Index (TDI) as an index of dilation was determined by dividing an area in initial image by an area in delayed image. There was no difference in TDI between patients with 1 vessel disease and controls, but TDI in patients with two vessel disease and patients with three vessel disease was larger than that in controls. Thus, transient dilation of the left ventricle on exercise Tl scintigraphy was likely to be related to number of stenotic vessel. We concluded that TDI as a simple quantitative index of transient dilation of the left ventricle was useful for detecting multi vessel stenosis.

Cardiomyopathy, Dilated↗
PubMed1989

[Ultrasonic tissue characterization by spectral analysis of myocardial textural pattern].

Based on the fact that ultrasonic myocardial textural patterns are more irregular in the pathological myocardium than in the normal, evaluation of the myocardial tissue character was attempted in vivo using spectral analysis. Parasternal left ventricular long-axis echocardiograms were obtained from five patients with old myocardial infarction diagnosed by history, electrocardiography and coronary angiography. These echocardiograms were transferred to an image analyzer and digitized (256 x 256 x 8). The waveforms of the gray-scale-changes from the normal myocardium showed periodicity in each 8-pixel cycle, but those from the infarcted myocardium did not. To quantify pattern changes in gray-scale values in the ultrasound beam direction, spectral analysis was performed by the maximum entropy method (MEM). There were four peaks in the MEM spectra both in the normal and infarcted myocardia, but there was a great significance in these patterns: with high, steep peaks in normal MEM spectra, and low, blunt peaks in infarcted ones. By discriminatory analysis of these four peak values, normalized by the whole spatial frequencies as multivariate, the misclassification rate was 4.8-22.7% in anteroseptal infarctions and 5.0-20.0% in posterior infarctions. Thus, spectral analysis of the myocardial textural pattern has advantages for analyzing routine echocardiograms without corrections by any absolute ultrasonic references. Furthermore, the misclassification rate is so low that we are able to characterize myocardial tissue.

Echocardiography↗
PubMed1989

[Evaluation of right ventricular systolic and diastolic properties using 81mKr scintigraphy with continuous infusion].

To evaluate right ventricular (RV) systolic and diastolic properties in patients with various heart diseases, RV volume curves obtained from 81mKr scintigraphy with continuous infusion were analyzed. The data were acquired in right anterior oblique position for five minutes, and from RV time activity curve and its first derivative curve, ejection fraction and peak ejection rate as systolic indices, and peak filling rate, time to peak filling and 1/3 mean normalized diastolic filling rate as diastolic indices were calculated. Ejection fraction in patients with dilated cardiomyopathy was lower than that in controls, but there was no difference in systolic indices among controls and patients with the other heart diseases. However, diastolic indices in patients with hypertrophic cardiomyopathy, patients with hypertensive heart disease, patients with dilated cardiomyopathy, patients with inferior myocardial infarction, and some patients with anteroseptal myocardial infarction were lower than those in controls. In conclusion, analysis of RV time activity curve by 81mKr scintigraphy with continuous infusion provides RV systolic and diastolic indices, which may permit evaluation of RV systolic and diastolic properties in various heart diseases.

Female↗
PubMed1989

[Effect of mexiletine on human atrial vulnerability].

The effect of mexiletine on human atrial vulnerability was investigated in 14 subjects (8 with paroxysmal atrial fibrillation, 2 with paroxysmal atrial tachycardia, 2 with ventricular tachycardia, 1 with sick sinus syndrome and 1 with Wolff-Parkinson-White syndrome). During the electrophysiologic study, after 8 consecutive stimuli (A1) were delivered through the electrode catheter positioned at high right atrium, premature stimulus (A2) was introduced, and following measurements were made; 1) Aw: atrial activity width of A1, 2) maximum atrial fragmentation (MAF): the longest atrial activity width of A2, which was expressed by the relative value against Aw, 3) fragmented atrial activity zone (FAZ): the zone of the coupling interval (A1A2) with the prolongation of the atrial activity width at A2 more than 150% against Aw, 4) conduction delay zone (CDZ): the zone of A1A2 with the prolongation more than 20 msec of the intraatrial conduction time at A2 from high right atrium to coronary sinus or low right atrium against the intraatrial conduction time at A1, and 5) right atrial effective refractory period (RAERP). These measurements were repeated after the intravenous administration of mexiletine (2 mg/kg/10 min). 3 cases (case 12, 13 and 14), whose FAZ and CDZ were 0 msec, were excluded from the following evaluation. Mexiletine showed little effect on Aw and RAERP, but significantly shortened MAF and FAZ (p less than 0.001 and p less than 0.05, respectively). CDZ were also reduced in 3 cases and remained unchanged in 6 cases, though no statistical difference of CDZ was recognized between before and after the administration of mexiletine.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Left ventricular pressure-volume diagram determined by forward and backward formatting of radionuclide ventriculography and analog pressure data].

Pressure-volume (PV) loop is of great value for the assessment of left ventricular (LV) function, but its clinical application has been limited by methodological complexity. A new system was developed to make accurate loop with simplified procedure, and was applied to clinical and interventional study. The system constitutes of a mobile gamma camera, a poly-amplifier and a data processor (GMS-550U, Toshiba Medical) installed in cardiac catheterization labo for simultaneous raw data handling and successive analysis. Since LV time activity curve (TAC) obtained by usual ECG gating is not fully reliable for a entire cardiac cycle, radionuclide data acquired in list mode was formatted forward and backward from ECG trigger together with analog data of LV pressure, ECG and PCG. PV loops were drawn in 10 patients (OMI, AP, MR, HCM) and 5 normals before and after infusion of angiotensin-II (AII), and Emax and LV work (systolic; SW, diastolic; DW, net; NW = SW - DW) were measured. Radionuclide ventriculography was safely performed with cardiac catheterization even in patients with congestive heart failure. Satisfactory PV loops were obtained by the advantage of simultaneous acquisition of RNV and analog data. Changes of ECG, PCG, volume, pressure and derived indices through one cardiac cycle were readily comparable each other. Peak LV pressure (mmHg) increased from 134 to 159 and then 182 by infusion of AII, but no change in heart rate was observed Emax was higher in normals and AP (mean 1.96 mmHg/ml/m2) than in OMI and MR (range of 0.85-1.36). SW increased in response to rise of LV pressure in all subjects. NW increased in normals and AP, but decreased in OMI and MR with relative increase in DW. In conclusion, this new system is feasible for repetitive studies under drug intervention, since it makes accurate PV loop under physiologic state, i.e. without pacing and volume overloading. Variable changes of SW, DW, and NW in response to afterloading were clarified, which may be useful for the evaluation of cardiac reserve in normal and diseased heart.

Angiotensin II↗
PubMed1989

[Nuclear cardiological examination for evaluation of hypertrophic cardiomyopathy with midventricular obstruction and apical aneurysm: a case report].

Midventricular hypertrophy (MVO) is a rare and complicated myocardial disease. Its pathophysiology and prognosis remain unknown, and few nuclear cardiological findings for MVO were reported. On a 44-year old man with MVO, thallium-201 (Tl) myocardial scintigraphy and gated blood pool scintigraphy (GPS) were performed to evaluate their usefulness. GPS revealed a characteristic hour-glass deformity of the left ventricular cavity, apical aneurysm and asynchrony due to obliteration of the midventricle. Anteroseptal hypertrophy in midventricle and myocardial damage in apico-inferior region were detected by Tl. Thus, nuclear cardiological studies are proved to be useful and essential in not only diagnosis but also evaluating pathophysiology and observing natural history noninvasively.

Adult↗
PubMed1989

Lectin histochemistry in rat thyroid tumours.

The thyroid tumours and background goiterous and adenomatous lesions induced in rats with diisopropanolnitrosamine (DIPN) plus methylthiouracil (MTU), and regenerative thyroid tissues after wounding were studied by lectin histochemistry. Ten weeks after cessation of the carcinogen treatments, carcinomas invading the surrounding tissues and blood vessels (13/20) and papillary micronodules (11/20) were formed in the thyroid tissues. In general, the carcinoma lesion was solitary, and the papillary micronodules were multiple in a single thyroid gland. Among the lectins tested, Maclura pomifera (MPA) and Solanum tuberosum (STA) showed specific binding with both carcinoma and papillary micronodule lesions, but not with the background goiterous and adenomatous lesions and regenerative thyroid tissues. The former both lesions showed higher labelling indices with BUdR or 3H-thymidine and poorer thyroglobulin accumulation than the latters, thereby indicating their enhanced proliferative capability and depressed potency of cyto-differentiation. The common cytological and histochemical properties of carcinoma lesions and papillary micronodules allow us to regard the latter as pre-invading carcinoma lesions. The lectins MPA and STA may be, therefore, used as the specific markers of malignancy in rat thyroid carcinogenesis.

Animals↗
PubMed1988

Effect of alpha-methyl-p-tyrosine and an antiserum to rat growth hormone (GH)-releasing factor (GRF) on plasma GH secretory profile during a continuous infusion of human GRF in rats.

The effects of alpha-methyl-p-tyrosine (alpha-MT) and an antiserum specific to rat growth hormone-releasing factor (GRF) on growth hormone (GH) secretory profile during a 6-h continuous infusion of human GRF(1-44) NH2 were observed in unrestrained adult male Wistar rats. All rats were provided with two indwelling cannulae; one in the right atrium for undisturbed blood collection and the other in the inferior vena cava for 0.9% NaCl or GRF infusion. GRF was administered by an infusion pump at a dose of 50 ng/kg b.wt./min ma GH levels during baseline period were low with little fluctuation. GH secretion was augmented significantly during continuous GRF infusion in control rats but interpeak intervals remained unaltered. When an antiserum specific to rat GRF was administered, episodic GH secretion was abolished. In these rats, pulsatile GH secretion indistinguishable from that of control rats was observed in the continuous presence of human GRF. Although alpha-MT inhibited episodic GH secretion, alpha-MT-treated rats exhibited high-frequency, low-amplitude episodic GH secretion and elevated baseline levels during the stimulation. There were no differences in the amount of GH secreted during GRF infusion between rats that had received either alpha-MT or antiserum to rat GRF. Since GH secretion to GRF is determined largely by somatostatin, the results suggest that phasic release of somatostatin plays an important role in determining the rhythmicity of episodic GH secretion, and that it is modulated by alpha-MT but not by the immunoneutralization of GRF.

Animals↗
PubMed1988

Molecular cloning of the cDNA for the large subunit of the high-Ca2+-requiring form of human Ca2+-activated neutral protease.

A nearly full-length cDNA clone for the large subunit of high-Ca2+-requiring Ca2+-activated neutral protease (mCANP) from human tissues has been isolated. The deduced protein, determined for the first time as an mCANP, has essentially the same structural features as those revealed previously for the large subunits of the low-Ca2+-requiring form (muCANP) [Aoki, K., Imajoh, S., Ohno, S., Emori, Y., Koike, M., Kosaki, G., & Suzuki, K. (1986) FEBS Lett. 205, 313-317] and chicken CANP [Ohno, S., Emori, Y., Imajoh, S., Kawasaki, H., Kisaragi, M., & Suzuki, K. (1984) Nature (London) 312, 566-570]. Namely, the protein, comprising 700 amino acid residues, is characterized by four domains, containing a cysteine protease like domain and a Ca2+-binding domain. The overall amino acid sequence similarities of the mCANP large subunit with those of human muCANP and chicken CANP are 62% and 66%, respectively. These values are slightly lower than that observed between muCANP and chicken CANP (70%). Local sequence similarities vary with the domain, 73-78% in the cysteine protease like domain and 48-65% in the Ca2+-binding domain. These results suggest that CANPs with different Ca2+ sensitivities share a common evolutionary origin and that their regulatory mechanisms are similar except for the Ca2+ concentrations required for activation.

Amino Acid Sequence↗
PubMed1988

Biochemical and physiological studies on a kallikrein-like enzyme from the venom of Crotalus viridis viridis (prairie rattlesnake).

A kallikrein-like enzyme was isolated from Crotalus viridis viridis (Prairie rattlesnake) venom by Sephadex G-50, DEAE-Sephacel and heparin-Sepharose CL-6B column chromatography. The purified enzyme has a molecular mass of 32 kDa and an isoelectric point of 5.4. The enzyme catalyzed the hydrolysis of arginine esters, kallikrein substrates Pro-Phe-Arg-MCA and Z-Phe-Arg-MCA. The specificity of the enzyme's substrate requirement is demonstrated by the fact that no proteolytic activity was detected against either dimethyl casein or fibrinogen. The enzyme also cleaves kininogen analogs to release bradykinin. Although the enzyme induced contraction of the isolated rat uterus directly at high concentrations, more forceful contractions resulted when the reaction mixture of the enzyme and bovine plasma was applied to the uterus. The reaction mixture of 5.10(-11) M of the enzyme and plasma caused contractions equal to that of 10(-9) M of bradykinin. Additionally the enzyme demonstrated capillary permeability-increasing activity and hypotensive activity on the anesthetized rat, suggesting that the enzyme releases the dilator of the wall of capillaries from plasma. Uterine contraction, capillary permeability-increasing activity and arginine esterolytic activity were inhibited by diisopropyl fluorophosphate, indicating that the serine hydroxyl group is essential for enzymatic and biological activities. It was demonstrated that the NH2-terminal region of the enzyme has significant similarities in sequence with kallikrein-like enzymes from other snake venoms and porcine pancreatic kallikrein.

Amino Acid Sequence↗
PubMed1988

Purification and characterization of a lethal toxin from the venom of Heloderma horridum horridum.

A lethal toxin was isolated from the venom of Heloderma h. horridum by gel filtration and ion-exchange chromatography. Molecular weight of the purified toxin was determined to be 28 kDa under reducing and nonreducing conditions. Biological activity, assayed by i.v. routes of injection, shows an LD50 for this preparation of 0.135 micrograms/g. Additionally, the toxin possesses an inhibitory effect on direct electrical stimulation of the isolated mouse hemi-diaphragm. However, neither hemorrhagic nor hemolytic activities were detected. Phospholipase A2 activity, proteolytic activity and arginine esterolytic activity were absent. The amino acid composition of the lethal toxin and the NH2-terminal sequence up to residue number 33 were determined. Neither show similarities to other components from H. h. horridum venom.

Amino Acid Sequence↗
PubMed1988

Non-frozen cold storage is favorable for islet function and morphology.

Freezing has been shown to damage pancreatic islets and to disrupt their insulin release, probably because of intracellular ice formation. We compared frozen islets with fresh ones and with others stored at temperatures above freezing from a standpoint of insulin release response to glucose and transplantation. Group A islets, isolated from rats and immersed in 10% dimethyl sulfoxide in RPMI 1640, were stored at -2 degrees C, and group B islets at -196 degrees C, for 7 days. As for group B, the islets were cooled at 1 degree C/min from room temperature to -40 degrees C, subsequently at 3 degrees C/min to -80 degrees C and then put into liquid nitrogen to be rapidly frozen to -196 degrees C. The control islets were fresh. In vitro, basal release at 3.3 mM glucose was similar in group A to that in the controls, but was higher in group B than group A. Stimulated release against 16.7 mM glucose was lower in group A than group B. However, insulin responsiveness, i.e., the ratio of insulin release at 16.7 mM glucose to that at 3.3 mM glucose, was lost in group B. Freezing also caused damage to the group B cells visible under the light and electron microscopes, while group A islets were largely intact. In vivo, after 600 islets were transplanted into streptozotocin-induced diabetic rats, group A was better able to lower fasting blood glucose than was group B, and remained so for 4 weeks. Above sub-zero preservation in the non-frozen state thus seems adequate for the short-term storage for 7 days.

Animals↗
PubMed1988

Autoradiographic study on healing process of cysteamine-induced duodenal ulcer in rat. Possible importance of Brunner's glands in ulcer healing.

The healing process of cysteamine-induced duodenal ulcer was studied by [3H]thymidine autoradiography. After the development of ulcer in the duodenum, cell proliferation was markedly activated not only in the crypts but also in the Brunner's glands near the ulcer. In the initial stages of ulcer healing, they both contributed to form the surface covering regenerating epithelium. Granulation tissue also proliferated at the base of the ulcer. In later stages of ulcer healing, new crypts were formed in the floor of the ulcer. New villi regenerated from these crypts and Brunner's glands regenerated by proliferation in situ. The ulcer base then was completely covered with new villi and granulation tissue was replaced by dense fibrous connective tissue. The present study suggested that the Brunner's glands, together with the crypts of Lieberkühn, play an important role in the healing process of cysteamine-induced duodenal ulcer.

Animals↗
PubMed1988

Isolation and characterization of horridum toxin with arginine ester hydrolase activity from Heloderma horridum (beaded lizard) venom.

A hemorrhagic toxin with lethal and arginine ester hydrolytic activities was isolated from Heloderma horridum (beaded lizard) venom by Sephadex G-75, DEAE-Sephacel, and Q-Sepharose column chromatography. The hemorrhagic toxin was shown to be homogeneous as demonstrated by a single band on acrylamide gel electrophoresis and immunodiffusion. Its molecular weight is approximately 31,000 with an isoelectric point of 3.9. Hemorrhagic, lethal, and benzoyl-L-arginine ethyl ester hydrolytic activities of this preparation were inhibited by diisopropyl fluorophosphate (DFP), N-bromosuccinimide, and beta-mercaptoethanol, suggesting that serine, tryptophan, and disulfide bonds are involved in these activities. Also there was an increase in creatine kinase activity in mice serum which is an indicator that the toxin is involved in muscle damage. This protein was stable to heat and pH ranges between 2 and 11. The Michaelis constant (Km), for benzoyl-L-arginine ethyl ester, and inhibition constant (Ki), for DFP, were found to be 6.9 X 10(-3) and 1.93 X 10(-4) M, respectively.

Amino Acid Sequence↗
PubMed1988

Characterization of clotting factors from Agkistrodon acutus venom.

1. Four clotting factors, Cf-1(C), Cf-2(C), Cf-1(T) and Cf-2(T) were isolated from Agkistrodon acutus (collected on mainland China and Taiwan) venom by Komori et al. (1987). It was reported that all factors possessed coagulant activity in the conversion of fibrinogen to fibrin, although they showed different chemical properties and antigenicities. 2. Their role in the clot formation system was clarified and compared with that of thrombin. Clotting factors from A. acutus venom released only fibrinopeptide A from the A alpha chain of fibrinogen, while thrombin released fibrinopeptide A and B from the A alpha and B beta chains. 3. Cf-1(C) and Cf-2(T), like thrombin, rapidly activated factor XIII in the presence of calcium ions, whereas Cf-2(C) and Cf-1(T) had little effect on factor XIII. These effects are shown by Cf-1(C) and Cf-2(T) forming a clot that remained insoluble in 8 M urea or 0.44 M monochloroacetic acid, whereas Cf-2(C) and Cf-1(T) formed a soluble clot in these agents.

Animals↗
PubMed1988

Kallikrein-like enzyme from the venom of Agkistrodon p. piscivorus.

1. A kallikrein-like enzyme was isolated from Agkistrodon p. piscivorus venom by Sephadex G-100, DEAE-Sephacel and S-Sepharose column chromatographies. 2. A kallikrein-like enzyme was shown to be homogeneous as demonstrated by a single band on acrylamide gel electrophoresis, sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunodiffusion. 3. Its molecular weight is approx. 29,000 with an isoelectric point of 7.8. 4. A kallikrein-like enzyme is able to cleave a kininogen analog to release bradykinin, and the B beta chain of fibrinogen. These proteolytic and tosyl-L-arginine methyl ester hydrolytic activities were inhibited by diisopropyl fluorophosphate, suggesting that the serine hydroxyl group is involved in enzymatic activities.

Amino Acids↗