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Biomedical subjects

H Sugihara

Publications and source records attributed to H Sugihara.

At least 415 records · Page 23Linked to original sources
PubMed1986

[Left ventricular function during atrial fibrillation assessed by left ventricular function curve using ECG-gated blood pool scintigraphy].

Cardiac function is difficult to assess in patients with atrial fibrillation due to the widely fluctuating cycle lengths resulting in variable ventricular hemodynamics. With respect to ECG-gated blood pool scintigraphy, distortion of the time activity curve occurs due to a summation of irregular cycle lengths. Therefore, performing such a study has been regarded meaningless. To evaluate left ventricular function during atrial fibrillation using scintigraphic technique, a new processing algorithm was devised to make multiple gated images which are discriminated by the preceding R-R interval, and left ventricular filling and function curves were established. The left ventricular filling curve, obtained by plotting end-diastolic volume against the preceding R-R intervals demonstrated an impairment of blood filling in cases of mitral stenosis and constrictive pericarditis, which resolved after mitral commissurotomy in case of mitral stenosis. The left ventricular function curve, established by plotting stroke volume against end-diastolic volume, was analyzed according to indices such as "slope" and "position". Both of these indices were significantly reduced in relation to the severity of heart failure according to the NYHA's functional classification and cardiomegaly on chest radiography. On individual comparisons of underlying diseases, the indices decreased in the following order; lone atrial fibrillation, hyperthyroidism, aging, hypertension, mitral valve disease, ischemic heart disease, dilated cardiomyopathy and aortic regurgitation. The indices correlated closely with ejection fraction. In cases of mitral regurgitation, however, the function curves were situated to the right and above those of lone atrial fibrillation and decreased in slope despite the fairly well-maintained ejection fraction. After treatment with digitalis and/or diuretics, the function curves shifted to the left and upward. In conclusion, left ventricular filling and function curves based on a newly-devised algorithm of ECG-gated blood pool scintigraphy are of considerable clinical value in evaluating cardiac performance in patients with atrial fibrillation. They are widely applicable to the assessment of therapeutic and interventional effects.

Atrial Fibrillation↗
PubMed1986

Glomerular injury in mice induced by Agkistrodon venom.

Glomerular injury was produced in mice after a single LD50 intravenous dose of purified 100-pace snake venom (Agkistrodon acutus). Characteristic features in glomeruli where the venom was demonstrated immunohistochemically included cystic lesions of the capillary tufts, thrombosis, subsequent proliferative and sclerotic changes, and crescent formation. Venom was recognized immunohistochemically in the glomerular endothelium, visceral basement membrane, mesangium, epithelium, and Bowman's capsule. Venom transfer across the basement membrane or into cells required less than 2 hours. Within this period mesangiolysis occurred due to the protease activity of the venom. Cystic lesions with fibrin thrombi then developed, which were replaced by proliferative and sclerotic changes after 3 days. Crescent formation began within 48 hours and was completed within a few days. Microangiography revealed hemodynamic changes in the intrarenal vasculature after venom treatment. Immune complex deposition was not found in any tissue. The study demonstrates the moderately constant potency (LD50) of Agkistron acutus venom, and documents it as a useful tool for quantitative studies of renal lesions.

Angiography↗
PubMed1986

[Left ventricular systolic performance during exercise in patients with hypertrophic cardiomyopathy].

The clinical profiles in patients with hypertrophic cardiomyopathy who had exercise-induced deterioration in systolic performance of the left ventricle (LV) were investigated using exercise echocardiography. The materials consisted of 32 patients, which who categorized in two groups according to the extent of % shortening fraction of the LV (% SF) at the peak exercise; 21 whose % SF was increased (group I: from 40.9 +/- 7.2% at rest to 44.2 +/- 8.0% at the peak exercise) and 11 whose % SF was decreased (group II: from 40.8 +/- 7.3% to 34.8 +/- 6.9%). There were no significant differences between these two groups as to the resting echocardiographic data or the prevalence of pressure gradient in the LV outflow tract. The frequency of symptoms, such as chest pain and exertional dyspnea, was higher in the group II (73%) than in the group I (38%). The time of exercise tolerance was significantly shorter in group II than in group I (I: 9.2 +/- 1.9 min., II: 7.4 +/- 2.6 min., p less than 0.05). Five patients (45%) in group II and four (19%) in group I developed at least 2 mm ST segment depression during exercise electrocardiography. Twenty-four hour ambulatory ECG monitoring showed a high prevalence of ventricular arrhythmias in group II. Seven (78%) of nine patients in group II and five (28%) of 18 in group I had abnormal 201T1 myocardial scintigrams. Left ventricular ejection fraction was not significantly different between the two groups, but the end-diastolic pressure was higher in group II (19 +/- 6 mmHg) than in group I (15 +/- 4 mmHg). All patients who underwent coronary arteriography had no significant stenosis. Thus, there are significant differences in the clinical features between the two groups of patients who had reciprocal LV responses during exercise. These findings should be considered in the management of patients with hypertrophic cardiomyopathy.

Adult↗
PubMed1986

[Cardiac inotropic reserve examined by postextrasystolic potentiation and redistribution of exercise thallium-201 scintigraphy].

Evaluation of regional contractile reserve and the viability of an infarcted segment of the myocardium is very important in determining the indications for aorto-coronary bypass after myocardial infarction and in predicting the prognosis. Regional wall motion of the left ventricle after postextrasystolic potentiation (PESP) was studied in 18 patients with old myocardial infarction, and compared with indices of redistribution of thallium after exercise. Equilibrium radionuclide angiocardiography (RNA) using Tc99m HSA was performed at rest and after PESP produced by a programmable cardiac stimulator via a right ventricular catheter. Regional ejection fractions (REF) were determined, and wall motion was observed visually. The relative thallium activity (RTA) and washout rate (WOR) were obtained from exercise myocardial scintigraphy performed 10 minutes, and 3 hours after thallium-201 injections. Wall motion improved in 12 of 23 infarcted segments after PESP. Regional ejection fraction and relative thallium activity (in three hours, or the difference between the activities of the initial and three hours after exercise) in the improved segments were significantly higher (p less than 0.001) than in the unchanged segments. Washout rate was lower (p less than 0.02) in the improved segments. Significant correlation was observed between the change in regional ejection fraction and relative thallium activity (3 hours after exercise) (r = 0.654, p less than 0.05). Thus, the wall motion of some infarcted regions of the myocardium improved after PESP, and thallium was redistributed during three hours after exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Exercise Test↗
PubMed1985

Isolation and characterization of hemorrhagic factors a and b from the venom of the Chinese habu snake (Trimeresurus mucrosquamatus).

Hemorrhagic factors a and b were isolated from Trimeresurus mucrosquamatus venom by Sephadex G-100, CM-Sephadex C-50 and DEAE-Sephacel column chromatographies. The hemorrhagic factors were homogeneous, as established by a single band on acrylamide gel electrophoresis, isoelectric focusing and sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. Molecular weights of 15 000 and 27 000 were found for hemorrhagic factors a and b, respectively. Factor a possesses proteolytic activity hydrolyzing the His(10)-Leu(11), Tyr(16)-Leu(17) and Arg(22)-Gly(23) bonds of oxidized insulin B chain, whereas, factor b hydrolyzed only the Ala(14)-Leu(15) bond. Hemorrhagic activity of these hemorrhagic factors was inhibited by ethylenediaminetetraacetic acid, 1,10-phenanthroline or p-chloromercuribenzoate, but not by soybean trypsin inhibitor or diisopropyl fluorophosphate. The hemorrhagic factors were injected into the skin of the back of albino rabbits, and the minimum hemorrhagic dose of factors a and b was 1.7 and 2.3 micrograms, respectively. These purified hemorrhagic factors were not lethal at 15 micrograms/g in mice. Factor a hydrolyzed the B beta chain of fibrinogen, while factor b hydrolyzed the A alpha chain. Hemorrhagic factor a was shown to differ immunologically from factor b. Factors a and b produced systemic hemorrhage in internal organs such as the heart and stomach of mice. Moreover, factor b produced hemorrhage in the liver.

Animals↗
PubMed1985

Cell proliferation and cell loss in intramucosal signet ring cell carcinoma of canine stomachs induced by N-ethyl-N'-nitro-N-nitrosoguanidine.

Signet ring cell carcinoma was induced in canine stomachs by N-ethyl-N'-nitro-N-nitrosoguanidine, and modes of cell proliferation and turnover in the carcinoma were studied by 3H-thymidine autoradiography in conjunction with morphometric analysis. From 2 to 15 months after the cessation of 8 months carcinogen treatment, carcinomas in an early stage were obtained. Most of the cancer tissues confined to the lamina propria showed a layered structure. This comprised three layers; the superficial and the deep layer were composed of signet ring cells, and the middle layer was composed of small round cells. The dogs were labeled with 3H-thymidine by s.c. injection and by local infusion of the celiac artery. Flash-labeled autoradiographs revealed that most 3H-thymidine incorporating cancer cells were located around the middle layer, with a small amount of mucin. Using a pulse labeling experiment, those labeled carcinoma cells were shown to migrate from the middle layer towards the surface. Morphometric analysis of the autoradiographs showed that the small cells in the middle layer migrated upwards and produced mucin to become full-blown signet ring cells by 5.5 days. In 15 days, most labeled cancer cells in the superficial layer had disappeared. This mode of cellular turnover appeared to mimic a cell renewal system of the normal gastric mucosa. If the cancer cells turn over in this way, the tumor must grow slowly, remaining as an intramucosal cancer for a relatively long period.

Adenocarcinoma, Mucinous↗
PubMed1985

Characterization of mucrotoxin A from the venom of Trimeresurus mucrosquamatus (the Chinese habu snake).

Mucrotoxin A from the venom of Trimeresurus mucrosquamatus was isolated in homogeneous form by a previously published method. Mucrotoxin A did not hydrolyze casein, however, when dimethylcasein was used as a substrate, the toxin cleaved the substrate. This toxin also hydrolyzed the oxidized B chain of insulin and fibrinogen. The sites of cleavage in the oxidized B chain of insulin were identified as Ser(9)-His(10), His(10)-Leu(11), Ala(14)-Leu(15), Leu(15)-Tyr(16) and Tyr(16)-Leu(17). The toxin digested the A alpha chain of fibrinogen first, followed by hydrolysis of the B beta chain. The fact that no fibrin clot formed indicates that the sites of cleavage in the A alpha and B beta chains of fibrinogen by the toxin must be different from those cleaved by thrombin. Mucrotoxin A produced systemic hemorrhage in internal organs such as the heart and stomach.

Animals↗
PubMed1985

Comparative study of three proteinases from the venom of the Chinese habu snake (Trimeresurus mucrosquamatus).

Three immunochemically distinct proteinases (P-1, 2 and 3) devoid of hemorrhagic activity were isolated from the lyophilized venom of Trimeresurus mucrosquamatus using column chromatography on Sephadex G-100, CM-Sephadex C-50, DEAE-Sephacel, CM-Cellulose and Bio-Rex 70. By these procedures, about 7.6, 7.3 and 8.2 mg of purified P-1, 2 and 3 may be obtained from 1 g of crude venom, respectively. The purified proteinases 1-3 were homogeneous by disc electrophoresis on polyacrylamide gel at pH 4.3, isoelectric focusing and by the presence of one precipitin line on immunodiffusion. The isoelectric point of P-1 was 8.1; P-2, 9.2; P-3, 9.8. The molecular weights of proteinases 1-3 were determined to be 23,000, 23,500 and 23,000, by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis, respectively. The purified proteinases 1-3 possessed caseinolytic and fibrinogenolytic activities. These activities were inhibited when the proteinases were incubated with the metal chelators ethylenediaminetetraacetic acid (EDTA), 1,10-phenanthroline or cysteine, but not with egg white trypsin inhibitor (EWTI) or soybean trypsin inhibitor (SBTI). P-1 cleaved the B beta-chain of fibrinogen first and then the A alpha-chain, whereas P-2 and 3 cleaved the A alpha-chain first and then the B beta-chain. However, these three proteinases did not hydrolyze the gamma-chain.

Amino Acids↗
PubMed1985

DNA content of diffusely infiltrative carcinomas in the stomach.

DNA content of diffusely infiltrative carcinomas of 15 Japanese patients, ranging in age from 38 to 65 years, was determined by cytofluorometry, using paraffin sections which were available for histological examination. Sections were stained with 0.0025% propidium iodide. By measuring the fluorescence intensity of at least 50 mitotic cells, ploidy patterns of the cancers were determined, whereas a control of the diploid DNA content was set by measuring the fluorescence intensity of mitotic cells in the non-cancerous gastric mucosa; only metaphase nuclei in the sections were considered to have a whole amount of nuclear DNA in the cytofluorometric measurement. In the present study, it was found that most of the diffusely infiltrative carcinomas consisted of a heteroploid cell line. Their stem DNA contents ranged between 2.8C and 4.8C (2C corresponds to a diploid amount of nuclear DNA). Of 15 cancers, four comprised a mosaic cancer of two different heteroploid cell lines. We encountered only one carcinoma containing a diploid cell line. However, this cancer also contained a heteroploid cell line. Six cancers contained a polyploid cell population, the DNA content of which was double of the stem DNA content. In most cases, the cancer cells distributed in the mucosal layer were also heteroploid, thereby suggesting a heteroploid origin of the diffusely infiltrative carcinomas.

Adult↗
PubMed1985

Studies on antianaphylactic agents. 7. Synthesis of antiallergic 5-oxo-5H-[1]benzopyrano[2,3-b]pyridines.

5-Oxo-5H-[1]benzopyrano[2,3-b]pyridine-3-carboxylic acids 23 and their tetrazole analogues 24 were synthesized from 4-oxo-4H-1-benzopyran-3-carbonitriles 3 or 2-amino-4-oxo-4H-1-benzopyran-3-carboxaldehydes 4. When administered intravenously, they exhibited antiallergic activity in a reaginic PCA test in rats. In the carboxylic acid series, the activity was influenced by the substituents at the 2-position and increased substantially in the following order: Me, OMe less than NH2 less than OH, H less than NHOMe. On the other hand, in the tetrazole series, 2-unsubstituted derivatives showed the highest activity. Regardless of the kinds of substituents at positions 2 and 3, compounds bearing an alkyl group, especially an isopropyl group at the 7-position, were superior in activity to the corresponding unsubstituted compounds. Among these alkyl derivatives, 3-carboxylic acid derivatives, i.e., 23c (7-ethyl), 23g (2-amino-7-isopropyl), 23r [2-(methoxyamino)-7-isopropyl], and a 3-tetrazole derivative 24c (7-isopropyl), were 41-184 times as potent as disodium cromoglycate. They also exhibited remarkable activity when administered orally; clinical studies on 23g (AA-673) are in progress.

Animals↗
PubMed1985

Adrenal cortex of Micromys minutus japonicus (Japanese harvest mouse). Its histochemical and fine structural study.

Micromys minutus japonicus (Japanese harvest mouse) is one of the smallest known mammals and is easily maintainable in the laboratory. The adrenal cortex of this animal is described here for the first time. The morphological structure with histochemistry was essentially the same as that of the mouse or the rat. However, the histochemical activity of steroid 3 beta-OH dehydrogenase in the zona glomerulosa was characteristically positive in this animal and electron microscopically Golgi's apparatus and endoplasmic reticulum were prominent in the glomerular cells. The concentration of aldosterone was high in the serum. These findings suggest the hyperfunction of the zona glomerulosa in this animal.

Adrenal Cortex↗
PubMed1985

Cellular structure and function of mouse adrenocortical tumor cells Y-1 in the post-treatment state of low Ca2+.

Under lowered Ca2+ content and in the post-treatment state of low Ca2+, we studied the cellular structure and functioning in mouse adrenocortical tumor cells, Y-1. These cells had been maintained in Ham F12 medium containing 10% fetal calf serum. The Ca2+ present in this complete medium was 0.39 mM. Under a slightly lowered Ca2+ (0.29 mM) produced by EGTA, the cells had many blebs on their surfaces and specific functional activity decreased in steroidogenesis as did ACTH reactivity. In the post-treatment state of a low Ca2+, the cellular surface was covered with many short microvilli and there was greater cellular activity than in the control cells. When the Ca2+ concentration was below 0.17 mM, the cellular structure and functioning were disturbed, and there was no recovery even at the physiological Ca2+ after the removal of EGTA.

Adrenal Cortex Neoplasms↗
PubMed1985

Production of antisera to growth hormone-releasing factor: usefulness in radioimmunoassay and passive immunization.

We have produced two antisera (R-1 & R-2) to human growth hormone-releasing factor (GRF) [1-44] NH2. Both antisera can be used for human GRF radioimmunoassay (RIA) at a final dilution of 1:50000. The antiserum R-2 was specific for the C-terminal amidated sequence of human GRF-44 and selectively recognized GRF [1-44] NH2 but not GRF [1-44] OH or GRF [1-40] OH. The antiserum R-1 also significantly bound 125I-rat GRF [1-43] OH at a final dilution of 1:5000 and enabled us to establish RIA for rat GRF. In both RIA systems, intra- and inter-assay coefficients of variation at 50% inhibition were 8 and 12%, respectively. A median effective dose was 90-120 pg in human GRF RIA and 250-300 pg in rat GRF RIA. Utilizing the RIA, we demonstrated that the hypothalamic GRF content in rats which received monosodium glutamate during the neonatal period was less than 20% of that of controls. However, the hypothalamic GRF content was not altered in rats made hypothyroid by methimazole administration, another condition known to greatly impair GH secretion. An iv administration of the antiserum R-1 significantly suppressed GH release following the injection of antisomatostatin serum. Thus, these antisera can be a useful tool in examining the physiological and/or pathophysiological roles of GRF in human and rat.

Animals↗
PubMed1985

Effects of S-596, a new beta-adrenoceptor blocking agent on the left ventricular performance of normal subjects during exercise.

The effects of d1-2-(3'-t-butylamino-2'-hydroxypropylthio)-4-(5'-carbamoyl-2'-thi enyl) thiazole hydrochloride (S-596) were evaluated in 9 normal volunteers. Exercise echocardiography was performed in the semi-supine position before and 2, 4 and 24 hours after the oral administration of 15 mg of S-596. Two hours after administration, resting heart rate was unchanged, compared with control, but systolic blood pressure at rest was slightly decreased (114 +/- 6 vs 106 +/- 10 mmHg, p less than 0.05). Left ventricular dimensions were unchanged, but shortening fraction was increased in the resting state (30.3 +/- 4.6 vs 33.1 +/- 4.8%, p less than 0.05). During exercise on oral S-596, heart rate and systolic blood pressure responses were reduced (127 +/- 11 in control vs 108 +/- 6 beats/min on S-596, 198 +/- 25 vs 168 +/- 23 mmHg, p less than 0.001 and 0.05, respectively). Left ventricular end-diastolic dimension was not significantly altered by S-596 compared with the preceding control exercise test; however, end-systolic dimension was significantly larger after beta blockade with S-596 (2.6 +/- 0.4 vs 3.0 +/- 0.4 cm, p less than 0.05). Shortening fraction and cardiac output decreased significantly (43.7 +/- 3.7 vs 40.0 +/- 5.7%, 9.5 +/- 1.4 vs 8.4 +/- 1.3 L/min, p less than 0.05 and 0.01, respectively). These effects of S-596 were maximal at 2 hours after oral administration with reduced response of heart rate to exercise lasting for 24 hours. Compared with the effects of propranolol (30 mg, given orally) in the same subjects, beta-adrenergic blockade during exercise with S-596 was equivalent to or greater than that of propranolol. Thus, S-596 has little, if any, effect on resting left ventricular performance, but demonstrates potent negative chronotropic and inotropic effects during exercise in normal human subjects. Its beta-adrenergic blocking action also has long acting properties, especially its chronotropic effect.

Adrenergic beta-Antagonists↗