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Biomedical subjects

H Sugihara

Publications and source records attributed to H Sugihara.

At least 307 records · Page 17Linked to original sources
PubMed1990

Characterization of a new inhibitor for angiotensin converting enzyme from the venom of Vipera aspis aspis.

1. Angiotensin converting enzyme inhibitor has been isolated from the venom of Vipera aspis aspis by gel filtration and reverse phase HPLC. 2. The purified inhibitor is a decapeptide, whose amino-terminal is blocked, with mol. wt 1044 determined by fast atom bombardment mass spectrometry. 3. The peptide inhibited the conversion of angiotensin I to angiotensin II, and Ki values were determined to be 7.54 x 10(-4) and 1.36 x 10(-4) M, respectively, using Hip-His-Leu and Hip-Gly-Gly as substrates 4. The peptide also inhibited the degradation of bradykinin, induced hypotension in spontaneously hypertensive rats and caused an increase in capillary permeability in rabbits, however, it possessed no lethality.

Amino Acid Sequence↗
PubMed1990

Isolation and characterization of factor X activator from the venom of Vipera aspis aspis.

1. A factor X activator was isolated from the venom of Vipera aspis aspis (Aspic viper) by gel filtration and ion-exchange chromatography. 2. The purified activator has a mol. wt of 75,000 and an isoelectric point of 4.6. Upon reduction, this activator migrated as two bands with mol. wts of 16,000 and 14,000 in sodium dodecyl sulfate polyacrylamide gel electrophoresis. 3. The activator from V. a. aspis venom shortened activated partial thromboplastin time (APTT) of normal plasma and factor IX-deficient plasma from humans. 4. Factor X incubated with isolated activator and calcium ions drastically shortened APTT of factor X-deficient plasma and expressed hydrolytic activity against synthetic substrates for factor Xa, however no hydrolytic activity was detected with the activator alone, indicating that the activator converted factor X to the active form.

Amino Acid Sequence↗
PubMed1990

Purification and physiological study of a hypotensive factor from the venom of Vipera aspis aspis (aspic viper).

A hypotensive factor was isolated from the venom of Vipera aspis aspis by Sephadex G-75, S-Sepharose column chromatography, and reverse phase HPLC using a Develosil 300 ODS-7 column. The purified factor was a basic protein with a mol. wt of 25,000 and an isoelectric point of 7.95. Intravenous injection of hypotensive factor induced an immediate fall in blood pressure of rats, whose duration depended on the dose employed. The hypotensive response was not affected by dithiothreitol, beta-mercaptoethanol, EDTA, p-tosyl-L-phenylalanine chloromethylketone, p-chloromercuribenzoic acid, or diisopropyl fluorophosphate, and was resistant to heat-treatment at 100 degrees C for 30 min, however, it disappeared after incubation with antivenom prepared against the hypotensive factor. The factor is devoid of proteinase, esterase, phospholipase A2 and kallikrein-like activities, and lethal, hemorrhagic and capillary permeability increasing activities are also absent. Compared to the hypotension induced by the hypotensive factor in normotensive rats, a more potent response was observed when it was administered to 11-week-old spontaneously hypertensive rats.

Amino Acids↗
PubMed1990

Comparative study of three phospholipase A2s from the venom of Vipera aspis.

1. Three phospholipase A2s, PLA2-I, PLA2-II and PLA2-III, were isolated from Vipera aspis venom by gel filtration and ion exchange chromatography. 2. Purified PLA2-I, -II and -III have mol. wts of 30,200, 16,000 and 13,500, and isoelectric points of 9.45, 7.65 and less than 4.1, respectively. 3. PLA2-I consists of an acidic subunit (mol. wt 13,700, pI: less than 3.5) and a basic subunit (mol. wt 16,500, pI: 10.6), which can be separated under highly acidic conditions. 4. PLA2-I possessed lethal activity and LD50 for this preparation was estimated to be 0.288 (0.209-0.397) micrograms/g, while lethality was not observed when PLA2-II, -III or each subunit of PLA2-I were administered. 5. Capillary permeability-increasing activity was found in the samples which possessed basic isoelectric points. Additionally, PLA2-I and its basic subunit drastically prolonged activated partial thromboplastin time of platelet rich plasma. 6. Intramuscular injections of PLA2-I, -II and -III increased serum creatine phosphokinase activity in mice, indicating that damage in muscle was caused by these enzymes. 7. NH2-terminal sequences of the three PLA2s were compared with other phospholipase A2s from snake venoms. Furthermore, antigenicities were tested using antiserum prepared against each sample.

Amino Acid Sequence↗
PubMed1990

Pathogenesis of hemorrhage induced by bilitoxin, a hemorrhagic toxin isolated from the venom of the common cantil (Agkistrodon bilineatus bilineatus).

The pathogenesis of hemorrhage induced by the i.m. injection of the hemorrhagic toxin, bilitoxin, was studied using light and electron microscopy. White mice were injected with sublethal doses of the toxin, and tissue samples were obtained at 5 and 30 min, and 1, 3 and 24 hr after the injection. There was a good correlation between amount of toxin injected and amount of hemorrhage observed. Microscopically, hemorrhage was visible in all parts of the connective tissue surrounding muscle cells just 5 min after injection and fibrin was present both intravascularly and extravascularly. At later time periods the hemorrhage was more extensive and there was more fibrin. Many vessels were plugged with platelets. At 30 min after the injection, muscle cells appeared to be damaged having either delta lesions or disrupted myofibrils. Electron microscopy revealed damaged capillaries with ruptured endothelial cells, disrupted basal lamina and intact intercellular junctions. Thus, this hemorrhagic toxin acts rapidly to disrupt the capillary endothelium without damaging the intercellular junctions, and it also appears to damage skeletal muscle cells.

Animals↗
PubMed1990

Primary structure of a hemorrhagic metalloproteinase, HT-2, isolated from the venom of Crotalus ruber ruber.

Crotalidae and Viperidae snake venoms contains several kinds of metalloproteinases which cause localized hemorrhage by direct action on blood vessel walls. We report here the entire amino acid sequence and the disulfide bridge locations of HT-2, one of the hemorrhagic toxins isolated from the venom of Crotalus ruber ruber (red rattlesnake). The non-reduced protein was first cleaved at methionine residues to provide a set of 8 fragments, which covered the entire sequence of HT-2. The disulfide bridge locations of HT-2 were also determined by using these primary fragments. The unambiguous sequence for the whole protein was then established by conventional methods using lysyl endopeptidase and thermolysin digests. HT-2 consisted of 202 amino acid residues with two disulfide bridges, which were assigned to Cys-117-Cys-197 and Cys-157-Cys-164. HT-2 had a typical zinc-chelating sequence His-Glu-X-X-His (residues 142-146) found in thermolysin, and its overall sequence showed, respectively, 50, 52, and 53% identities to those of HR2a, H2-proteinase, and the metalloproteinase domain of HR1B. However, the disulfide bridge locations of HT-2 were different from those in the other metalloproteinases. The primary structure of HT-2 was more closely related to that of Ht-d from Crotalus atrox recently determined (81% identity). From the structural comparison with five metalloproteinases so far elucidated, six conservative amino acid residues, which may possibly be related to the induction of the hemorrhagic activity, were suggested to be present in these toxins.

Amino Acid Sequence↗
PubMed1990

Chromosome abnormalities of gastric cancer detected in cancerous effusions.

The chromosomes were examined in cancerous effusions obtained from 7 patients with gastric cancer. In 1 patient, the modal chromosome number was 46 with a normal chromosome complement in the majority of the cells examined. The other 6 patients revealed numerical and structural aberrations. Among the structural rearrangements detected, chromosome 3 was involved in the short arm and in the long arm, each in three patients; bands p25, q21, q23, and q27 were recurrently involved and a band q23 was lost in 3 patients. Rearrangements of chromosome 5 in the long arm and of chromosome 17 at or near the centromere were also observed in three patients each. Gains of chromosome 7 was seen in 5 patients and of chromosome 13 in 4. Some of these alterations may be specific for gastric cancer.

Adult↗
PubMed1990

Variability of protection against different strains induced by a culture filtrate (CF) obtained from Salmonella enteritidis.

Cross-protective ability against the challenge of different strains of culture filtrate (CF) obtained from Salmonella enteritidis was investigated. Immunization with CF from various smooth strains with the exception of strain 3551 which is a rough strain of S. enteritidis induced protective immunity against challenge with strains 2547 and 116M. However, when strains 2822, 3551 and 3975 were used as the challenge strain, no protective effect was observed. The agglutination titers against whole cells of strain 2547 or 2822 of sera taken from the 2547 CF-immunized mice were almost the same as those of sera from the 2822 CF-immunized mice. Furthermore, delayed footpad reactivity was observed when heat-killed cells of strain 2547 or 2822 were transferred into the footpad of 2547 CF- or 2822 CF-immunized mice. These results show that the capability of inducing protective immunity is similar between the 2547 CF and 2822 CF, and protection against infection with S. enteritidis differs in accordance with different challenge strains.

Animals↗
PubMed1990

Biological and chemical studies on soluble protective antigen (SPA) from culture supernatant fluids of Salmonella enteritidis.

The chemical and biological characteristics of Soluble Protective Antigen (SPA) separated from culture fluids of Salmonella enteritidis strain 2547 were analysed. It was shown that SPA has 3-hydroxy, nonpolar fatty acids by thin-layer chromatography. The fatty acids were identified as lauric, myristic, palmitic and 3-hydroxymyristic acid using gas chromatography-mass spectrometry and mass chromatography. These fatty acids are common constituents of the lipid A obtained from S. enteritidis. SPA was found to enhance the plaque-forming cell (PFC)-response to sheep erythrocytes in the recipients' spleen. In addition, SPA enhanced the clotting activity of Limulus amebocyte lysate. These results show that SPA possesses the properties of lipopolysaccharides isolated from strain 2547 by chemical procedures.

Animals↗
PubMed1990

Immunological studies on soluble protective antigen (SPA) separated from culture supernatant fluids of Salmonella enteritidis.

Studies were carried out to analyze the antigenicity of Soluble Protective Antigen (SPA) separated from culture supernatant fluids of Salmonella enteritidis strain 2547. Mice injected with anti-SPA mouse serum were capable of tolerating a challenge dose of 100 LD50 S. enteritidis. After absorption of the anti-SPA mouse serum with lipopolysaccharide (LPS) prepared from strain 2547, no protective effect was observed. Ouchterlony immunodiffusion analysis showed that the P1 fraction obtained from Sephadex G-50 gel filtration of strain 2547 or 2822 LPS reacted with antiserum to SPA, but no reaction was observed with the P2 or P3 fraction. The LPS from strain 2547 gave 80% mouse protection against challenge with 100 LD50 of the homologous bacteria, while the P1 from strain 2547 LPS afforded 40% protective immunity. When P1, LPS and SPA were transferred into the footpad of SPA-immunized mice, a positive delayed footpad reaction was elicited. Similarly, macrophage migration inhibitory activity was observed when SPA-induced peritoneal exudate cells were cultured in medium containing P1, LPS and SPA. These results suggest that the antigenic determinant of SPA exists in the O-antigenic components of LPS.

Animals↗
PubMed1990

Reconstruction of thyroid follicles from isolated porcine follicle cells in three-dimensional collagen gel culture.

Thyroid follicles, an essential functional unit of the thyroid, are ball-like structures and exist in the extracellular matrix in vivo. Thus far, the follicles have not been reconstructed in any culture system. The presumed reason for that was that the in vitro environment for the follicle cells in monolayer culture markedly differed from their environment in vivo. We, therefore, considered that isolated follicle cells had to be localized in a three-dimensional environment of extracellular matrix, specifically collagen, to reconstruct thyroid follicles in vitro. At first, follicle cells were completely isolated. These cells were cultured in the three-dimensional collagen gel. An intracytoplasmic cavity first developed in individual cells. A single cell with the cavity then underwent cell division, and the follicle consisting of two cells was reconstructed. This gradually grew to be a large ball-like structure through proliferation of the component cells, and they exhibited morphological polarity specific for thyroid follicle cells. In addition, these cells clearly produced thyroid hormones. To the best of our knowledge, this report is the first instance of reconstruction of thyroid follicles in an in vitro culture system. This culture system is more useful than the monolayer culture system in that this system provides a more physiological environment for investigations of differentiation of follicle cells. Further experiments using this method will probably provide a new clue to the mechanism of thyroid folliculogenesis.

Animals↗
PubMed1990

An enzymatic assay of chloramphenicol coupled with fluorescence reaction.

An alternative method for the assay of chloramphenicol using an enzymatic reaction coupled with a fluorescence detection system has been developed. Chloramphenicol was enzymatically acetylated by chloramphenicol acetyltransferase in the presence of acetyl-coenzyme A (acetyl-CoA) as the acetyl-donor, after which the liberated CoA-SH was derivatized with a fluorogenic reagent, 4-(aminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole. The assay was linear over the range of 2.5-40 micrograms/ml. Analytical recoveries of chloramphenicol at concentrations of 7.5 and 22.5 micrograms/ml, added to human serum, plasma, or a slightly hemolyzed serum, were in the range of 93.3 to 106.2%. The enzymatic assay was not affected by the presence of ten other antibiotics tested.

Chloramphenicol↗
PubMed1990

[Value and limitations of stress thallium-201 scintigraphy in evaluating the viability of infarcted myocardial segments].

The aim of this study was to evaluate the value and limitations of stress thallium-201 scintigraphy in evaluating the viability of infarcted myocardial segments following percutaneous transluminal coronary angioplasty (PTCA) and aortocoronary bypass surgery. The relative thallium activity (RTA: the ratio of the count rate in the infarcted segment to that in the intact segment) obtained from delayed images of stress myocardial scintigraphy was used as an index of myocardial viability and was compared with the following parameters. 1) Thallium-201 myocardial perfusion images were made during transient coronary arterial occlusion (PTCA) in eight patients with old myocardial infarction. The RTA of delayed images after successful PTCA was compared with those of stress thallium-201 scintigraphy. There were no significant differences of the RTA between delayed images following PTCA and those of stress myocardial scintigraphy. We therefore, presumed that incomplete redistribution of the delayed images of stress thallium-201 scintigraphy did not truly reflect the degree of coronary stenosis. 2. Regional ejection fraction of the left ventricle after postextrasystolic potentiation (PESP) using equilibrium radionuclide ventriculography was studied in 18 patients with old myocardial infarction, and was compared with the RTA of delayed images of stress myocardial scintigraphy. A significant correlation was observed between the changes in regional ejection fraction by PESP and the RTA three hours after exercise. 3. The RTAs of early and delayed thallium-201 scintigrams were measured at rest in 30 patients with old myocardial infarction, and were compared with the RTA of delayed thallium 201 scintigrams after exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗
PubMed1990

[Coronary flow reserve index corrected by exercise load using Tl-201 SPECT: evaluation by PTCA].

For simple, non-invasive evaluations of coronary flow reserve during exercise, we investigated the coronary flow reserve index using the ratio of change of fractional distribution in the regional myocardium to oxygen demand. The subjects included 24 patients with effort angina pectoris and 11 normal volunteers. PTCA was performed for 11 patients. Using the biological properties of Tl-201, single photon emission computed tomography (SPECT) was performed at submaximal exercise and at rest by two successive injections of Tl-201 within a short time interval (double dose method). The correlation between the fractional distribution in the myocardium (delta-Fract) and the oxygen demand during exercise and at rest were evaluated. delta-Fract correlated well with the rate of change of the pressure rate product (delta-PRP), and delta-Fract/delta-PRP (CRI) was a good indicator of the coronary flow reserve index. CRI in the ischemic region correlated well with the percent area stenosis of the supplying coronary artery and improved with resolution of percent area stenosis of the target coronary artery after PTCA, but in some cases they were not above the normal range. CRI as obtained by exercise SPECT using the double dose method is useful for non-invasively estimating the coronary flow reserve during exercise, and it can be used for evaluating the effect before and after PTCA.

Angina Pectoris↗
PubMed1990

[Long-term follow-up of electrocardiographic changes in patients with asymmetric apical hypertrophy].

The serial electrocardiographic (ECG) changes of 20 patients with asymmetric apical hypertrophy (AAH) were retrospectively reviewed relative to their clinical symptoms, echocardiography and Doppler echocardiography, and thallium-201 perfusion scintigraphy. These patients were followed 4-18 years (mean 8 years). Patterns of the serial ECG changes were as follows: Seven patients (group Ia) had an increase of 10 mm or greater in the highest R wave amplitude in the precordial leads, with newly-developed giant T wave inversion. Five patients (group Ib) had relatively stable ECGs and the changes in the R wave amplitudes of less than 10 mm. Six patients (group IIa) had a decrease of 10 mm or greater in the highest R wave amplitude with mild decreases of negative T wave amplitudes. In the remaining two patients (group IIb) right bundle branch block developed. At the last follow-up study, group IIa had lower R wave amplitudes and longer QTc than did those in group I. The follow-up periods and their mean age did not differ among the groups. At the initial evaluation, exercise limitation was rare in group I; whereas, most of the patients in group II presented symptoms such as palpitation, chest pain or exertional dyspnea. These cardiac symptoms developed slowly but progressively during the follow-up period, and their incidence increased both in groups I and II at the final observation. Left ventricular (LV) wall thickness at the chordal level showed normal values and did not differ between the two groups, but apical wall thickness was greater in group II than in group I. Two-dimensional echocardiography showed a spade-like deformity of the LV in group II. In group I, the LV deformity was less marked and was not noted at the initial examination. Color Doppler echocardiography frequently revealed "paradoxical flow" expelled from the obliterated apex to the base in the early diastolic filling period in group II. Left ventriculography confirmed asynchronous contraction, hyperkinesis in the basal segment and dyskinesis at the apical segment, resulting in this abnormal intraventricular blood flow profiles. Serial studies by thallium-201 (TL) perfusion scintigraphy disclosed that four of the eight patients in group II developed localized hypoperfusion at the apex where a high and homogeneous uptake of TL was previously noted.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1990

[Regional myocardial blood flow measurements in resting and dipyridamole induced vasodilative state by Xenon-133 clearance method].

Myocardial imaging with Xenon-133 and a gamma camera was employed to evaluate the relationship between angiographically demonstrated coronary artery stenosis and regional myocardial blood flow (r-MBF) in 22 patients with ischemic heart disease and 9 control subjects. After a left anterior oblique cineangiogram was obtained, the cinecamera was replaced by the mobile gamma camera in the same plane and location over the pericardium of patients. Then, 370 MBq (10 mCi) of 133Xe was injected into the left coronary artery as a bolus. After the first measurement of r-MBF in resting state, a second injection was made 3 minutes after intravenous injection of 0.56 mg/kg of dipyridamole for 4 minutes. The r-MBF in different regions of the heart was calculated by Kety formula. Coronary flow reserve (CFR) was defined the rMBF ratio between resting and dipyridamole induced vasodilative state. In the resting state, good correlation (r = 0.711) was observed between pressure rate product and the r-MBF at the areas perfused by non stenotic vessels. The r-MBF of the areas perfused by severe stenotic vessels (greater than 90%) was smaller than that of the areas perfused by non stenotic vessels, however there was overlapping of flow. In the dipyridamole induced vasodilative state, the r-MBF of the areas perfused by intact vessels increased approximately 2.4 times of the resting state, and showed good correlation with pressure rate product. In contrast, the r-MBF of the areas perfused by stenotic vessels did not correlate with pressure rate product, but depended on the degrees of coronary stenosis (50-75% stenosis; 1.9 times, greater than 90% stenosis; 1.3 times, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗