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Biomedical subjects

S Yoshihara

Publications and source records attributed to S Yoshihara.

At least 109 records · Page 6Linked to original sources
PubMed1993

Distribution of antigens of Fasciola gigantica at various stages of development.

An indirect immunofluorescent antibody test on the serum of a Fasciola gigantica-infected rabbit, showed specific fluorescence on the tegumental surface of miracidia, sporocysts, rediae, cercariae, metacercariae and juvenile worms aged between one and seven weeks. The same reaction occurred in the gut cells of cercariae and metacercariae and in the gut caeca of juveniles in the liver. The results of the absorption test indicated that stage-specific antigen(s) in metacercariae and seven-week-old worms existed mainly in the gut cells and the gut caeca, respectively. The precipitating antibody reacting to metacercariae antigens occurred at a very early stage of infection, but the titre dropped much earlier than that against the juvenile antigen.

Animals↗
PubMed1993

Studies on the toxicities of aluminium hydroxide and calcium phosphate as immunological adjuvants for vaccines.

Aluminium hydroxide (Al) and calcium phosphate (Ca) have been used for many years as immunological adjuvants for biologicals. We investigated the toxic effects of both adjuvants with different physical properties. Al-gel elicited vascular permeability-increasing and toxic effects to macrophages (M phi), while its haemolytic effect was weak. Ca-gel elicited a significantly stronger haemolytic effect, but no other toxic effect. Incubation of M phi or polymorphonuclear leucocytes with Al-suspension resulted in the largest release of lactate dehydrogenase. Ca-suspension caused haemolysis of about 50% of that caused by Ca-gel.

Adjuvants, Immunologic↗
PubMed1993

Use of body fluid of adult female Ascaris suum as an antigen in the enzyme-linked immunosorbent assay (ELISA) for diagnosis of swine ascariosis.

The Enzyme-linked immunosorbent assay (ELISA) was used to detect Ascaris suum antibodies in swine sera with adult body fluid (ABF) as an antigen. The assay was standardized with respect to the antigen concentration and serum and conjugate dilutions. Cross reaction was found between the antigen and the sera from the swine infected with Metastrongylus apri. The ELISA was more sensitive than the complement fixation test. Five protein peaks were obtained from ABF by gel filtration on Sephacryle S-300. Fraction 1 was the most specific. A 105 kDa protein in the fraction reacted with swine IgG in the serum of infected animals in Western blot analysis.

Animals↗
PubMed1993

Intracellular magnesium deficiency in acute myocardial infarction.

It has been hypothesized that intracellular magnesium deficiency is a pathogenetic factor in acute myocardial infarction. This study examined the time course of changes in the erythrocyte magnesium concentration and the correlation between the erythrocyte magnesium concentration and the severity of acute myocardial infarction in 49 consecutive patients with transmural acute myocardial infarction. The data were compared with results from 20 control patients without ischemic heart disease. The erythrocyte magnesium concentration (mg/dl) decreased significantly during the acute phase of the infarction (4.86 +/- 0.09 on day 1, 4.89 +/- 0.10 on day 2 and 4.86 +/- 0.10 on day 3 versus 5.26 +/- 0.19 for controls, all P < 0.05) and then normalized gradually to 5.25 +/- 0.10 on day 28. The serum magnesium concentration (mg/dl) also decreased significantly during the acute phase of the infarction (1.93 +/- 0.04 on day 1 and 2.11 +/- 0.03 on day 2 versus 2.26 +/- 0.08 for controls, all P < 0.05), before recovering to 2.28 +/- 0.06 on day 28. There were significant correlations between the erythrocyte magnesium concentration on day 1 and maximal values of serum cardiac enzymes (r = -0.30 for creatine kinase, r = -0.34 for glutamic oxaloacetic transaminase and r = -0.57 for lactate dehydrogenase, all P < 0.05). Moreover, the erythrocyte magnesium concentration was significantly lower in patients with (4.32 +/- 0.08 mg/dl, n = 13) than in those without (5.06 +/- 0.09 mg/dl, n = 36, P < 0.0001) serious arrhythmias. These data indicate that intracellular magnesium deficiency is involved in the acute phase of myocardial infarction.

Adult↗
PubMed1993

A novel skeletal drug delivery system using self-setting bioactive glass bone cement. IV: Cephalexin release from cement containing polymer-coated bulk powder.

A novel device consisting of Eudragit-coated cephalexin as a model drug and a self-setting bioactive cement based upon CaO-SiO2-P2O5 glass was investigated. The glass cement hardened within 5 min of mixing with a phosphate buffer. After setting, in vitro drug release from homogeneous or heterogeneous drug-loaded cement pellets in a simulated body fluid (SBF) at pH 7.25 and 37 degrees C continued for over 2 weeks. The hardened cement gradually formed low-crystallinity hydroxyapatite and decreased in volume by about 5% during drug release in SBF. Consequently, 30% of the loaded drug was initially released from the homogeneous cement system, and thereafter it was released more slowly. Since the heterogeneous system consisting of the cement and a 50% polymer coated, drug-loaded pellet avoided this drug's burst, the drug was released over a longer period than that in the homogeneous system. The heterogeneous system released the polymer-coated drug very slowly, because it completely avoided the initial burst, and sustained the release over a long period.

Biocompatible Materials↗
PubMed1993

[Skin test reactivity to histamine in childhood].

One hundred twenty five allergic patients ranging in age from 0 to 36 years old (mean age 9 years) were tested. Intradermal skin tests were performed on the volar surface of the forearm by injection of a five-fold dilution of histamine dihydrochloride (from 1 x 5(-5) mg/ml to 1 x 5(-2) mg/ml). The wheal diameters increased incrementally with histamine concentration. The whealing capacity of the skin to histamine was found to be significantly lower in patients 0 to 5 years of age. There was no difference in the mean wheal size between patients 6 to 10 and 11 to 15 years of age. The wheal size in patients 16 to 36 years of age were significantly larger than those in the other age groups. The flare diameters also increased incrementally with histamine concentration. The mean diameter of flares was significantly lower in patients 0 to 5 years of age. Concentrations between 1 x 5(-3) mg/ml and 1 x 5(-2) mg/ml of histamine dihydrochloride should be taken for a positive control in intradermal allergen skin tests.

Adolescent↗
PubMed1993

[Treatment of intrahepatic gallstone].

The postoperative outcomes in patients with hepatolithiasis are greatly affected by the presence of residual stones. One hundred and seventeen patients with hepatolithiasis treated in our clinic were analysed. The indication of hepatectomy for hepatolithiasis was determined by the degree of stricture of intrahepatic bile duct. The rate of residual stones was reduced from 54.5% to 14.5% by the introduction of choledochoscopical lithotomy. Thus, pre- and postoperative choledochoscopical examination and lithotomy are shown to play an important role in treatment of the patients with hepatolithiasis.

Adult↗
PubMed1992

Alcohol-induced sinus bradycardia and hypotension in patients with syncope.

We observed 2 cases of repeated episodes of syncope after alcohol ingestion. Both patients were light drinkers and had carotid sinus hypersensitivity. In both cases, alcohol loading tests repeatedly induced sinus bradycardia and hypotension 1.0-1.5 hours after drinking alcohol. Atropine was effective in improving symptoms. A loading test using a glucose solution of equivalent osmolarity and volume was negative. Acute alcohol ingestion usually increases heart rate with variable effects on blood pressure. However, our 2 cases exhibited unusual alcohol-induced sinus bradycardia and hypotension, suggesting a paradoxical increase in parasympathetic activity and/or decrease in sympathetic activity.

Aged↗
PubMed1991

A new bioactive bone cement: its histological and mechanical characterization.

We have developed a bioactive bone cement using CaO-SiO 2-P 2O 5-CaF 2 glass powders and ammonium phosphate solution, and investigated its histological and mechanical characteristics in vivo. A bone defect was drilled in proximal metaphysis of the rat tibia and filled with the bioactive bone cement in paste form or polymethylmethacrylate (PMMA) bone cement in the dough state. The cements were allowed to harden in situ. Histological examination demonstrated direct bonding between the new cement and bone by 4 weeks. The bioactive bone cement did not degrade up to 24 weeks postimplantation. The inflammatory reaction to the bioactive bone cement was less intense than the reaction induced by PMMA. Changes in the mechanical properties of the cement in vivo were studied by implanting hardened cylindrical specimens of both types of cement into the hindlimb muscles of rats for 12 weeks. The compressive strength of the bioactive cement increased significantly after implantation, and reached 68 MPa in 1 week and 73 MPa in 4 weeks. These values were comparable to those of PMMA, and were maintained up to 12 weeks after implantation. This bioactive bone cement hardens in situ within a few minutes with negligible rise of temperature and can be easily handled as a paste for filling bone cavities of different shapes. In addition, this cement has good osteoconductive and bone bonding potential and fairly high mechanical strength. Therefore, this new cement could be used both as a bioactive bone cement and bone defect filler.

Animals↗
PubMed1991

Enhancement of post-hypoxic contractile and metabolic recovery of perfused rat hearts by dl-propranolol: possible involvement of non-beta-receptor mediated activity.

The present study was undertaken to elucidate a possible role of non-beta-receptor mediated effects in dl-propranolol-induced enhancement of post-hypoxic contractile and metabolic recovery in perfused rat hearts. The rat hearts were perfused for 30 min under reoxygenated conditions following 15 min-substrate free-hypoxic perfusion, and the cardiac performance and myocardial metabolism were examined. Hypoxia induced complete cessation of cardiac contractile force, depletion of myocardial high-energy phosphates, release of ATP metabolites and creatine kinase from the heart. Subsequent reoxygenation produced little recovery of cardiac contractile activity and tissue high-energy phosphates, further enhancement of the release of creatine kinase and the accumulation of tissue calcium. Treatment of the hypoxic hearts with dl-propranolol, d-propranolol and atenolol was performed during 5 to 15 min of hypoxic perfusion. dl-Propranolol and d-propranolol at the concentration of 45 microM elicited a significant recovery of cardiac contractile activity and restoration of myocardial high-energy phosphates. This treatment also resulted in a suppression of the release of creatine kinase and ATP metabolites and the tissue calcium accumulation observed during hypoxia and/or reoxygenation. However, such beneficial effects were not seen in hearts treated with 45 microM atenolol. dl-Propranolol and atenolol, but not d-propranolol, in a concentration of 45 microM have been shown to reveal beta-adrenoceptor blocking action. Thus, the results suggest the involvement of non-beta-receptor mediated effects of propranolol in the enhanced post-hypoxic contractile and metabolic recovery of the perfused rat heart. The non-beta-receptor mediated activity of these drugs appears to be related to their ability to suppress the maximal driving frequency of left atrial preparations.

Animals↗
PubMed1991

Effects of hydrogen ion on the changes in adenosine production in the isolated rat heart perfused at a constant flow system.

This study was designed to clarify the relationship between the change in H+ and the nucleoside concentration at a constant coronary flow rate using a Langendorff system. Wistar rat hearts were perfused with Krebs-Henseleit solution (control, pH 7.4) modified to be either acidotic or alkalotic. Coronary perfusion pressure (CPP), left ventricular pressure, and myocardial oxygen consumption were decreased in the acidotic perfusate. On the other hand, these parameters increased in the alkalotic perfusate. Adenosine production in the acidotic perfusate significantly decreased while it significantly increased in the alkalotic perfusate. Furthermore, there was a significant positive correlation between both the percent change in adenosine production and the percent change in CPP in acidosis and alkalosis. It is suggested from these results that the hydrogen ion affects the adenosine metabolism and that the change in coronary blood flow by H+ is at least partly regulated by adenosine.

Acid-Base Equilibrium↗
PubMed1991

Breathing patterns during sleep in stable asthmatic children.

Breathing patterns during sleep at night were studied in 15 asymptomatic asthmatic children and 11 nonasthmatic controls using impedance pneumography. Inspiratory time (TI), expiratory time (TE) and expiratory time/inspiratory time ratio (TE/TI) were used as the indices of breathing patterns. In the daytime, TI, TE and TE/TI, showed no significant differences between asthmatics and controls. During nocturnal sleep, TE and TE/TI increased significantly in the asthmatics compared with the value during daytime, while these values showed only a small variation overnight in the controls. TI showed no significant changes through the night in either the asthmatics and the controls. The results of this study indicate that the stable asthmatic children had abnormal breathing patterns during nocturnal sleep.

Adolescent↗
PubMed1990

A bioactive glass powder-ammonium hydrogen phosphate composite for repairing bone defects.

Bioactive glass powder (AW-G) was made into a rigid compound by mixing with ammonium hydrogen phosphate and was evaluated as a bone-defect filler. The proximal metaphysis of the rat tibia was drilled and packed with (a) polymethyl-methacrylate (PMMA) bone cement, (b) AW-G powder, (c) AW-G powder with ammonium hydrogen phosphate (AW-G)-(A-P), or (d) nothing, as a control. The animals, with different implantation periods up to 24 weeks, were sacrificed and the defective sites were histologically analyzed. The results revealed direct bonding between the bone tissue and the (AW-G)-(A-P). The general inflammatory reaction of (AW-G)-(A-P) was less than that of PMMA bone cement. The compressive strength of (AW-G)-(A-P) implanted subcutaneously into rats was measured chronologically and deterioration did not occur during a period of 24 weeks. The rigidity increased to 1.6 times 6 months after implantation as compared with the initial value. This compound can be used as paste and is transformed into a rigid compound in about 4 min without noticeable elevation of the temperature. Thus, this (AW-G)-(A-P) composite can be used as a bone defect filler, and there is a possibility that it can even be used as a bone cement if higher rigidity can be attained.

Animals↗
PubMed1989

Quantitative determination of sulfated glycopeptide by two-dimensional electrophoresis on cellulose acetate membrane.

Quantitative determination of the sulfated glycoproteins present in tissue and secretion fluid was performed. After digestion of the specimen with pronase in order to convert glycoproteins to glycopeptides, the sulfated glycopeptides were separated from a mixture of acidic glycans (glycosaminoglycans, sialoglycopeptides and sulfated glycopeptides) by two-dimensional electrophoresis on cellulose acetate membrane [(1986) J. Biochem. Biophys. Methods 12, 239-246]. After staining with alcian blue, the spot of sulfated glycopeptide on the cellulose acetate membrane was cut out, and then only the dye bound to the sulfated glycopeptide was extracted with a 5% cetylpyridinium chloride solution at 100 degrees C for 15 min. The extract was then measured by absorbance at 615 nm using an authentic sulfated glycopeptide as a standard. This method facilitated the determination of sulfated glycopeptides, which were separated from other acidic glycans, within the range 0-25 micrograms.

Animals↗
PubMed1989

[Using specific radioimmunoassay for guinea pig VIP (GP VIP), immunoreactive GP VIP levels in respiratory tract tissue of normal and airway-allergic guinea pigs].

Vasoactive intestinal polypeptide (VIP) has recently received widespread attention with respect to its control of airway constriction, and is now regarded as the most promising candidate as a neurotransmitter for nonadrenergic noncholinergic inhibitory nerves in the airway. A specific system of radioimmunoassay (RIA) was devised to measure guinea pig VIP (gp VIP) concentration in airway tissue. An antiserum, R 550, was obtained by immunizing rabbits with newly synthesized gp VIP. The detectable VIP concentration was assessed to be 10 fmol/tube with the RIA system. The concentration of gp VIP in the respiratory tract tissue of normal guinea pigs was 0.04-0.22 pmol/g wet weight of tissue. The VIP level was highest in the trachea, in contrast to lower levels in both the major bronchus and lower lung. After being passively sensitized with ovalbumin, the experimental guinea pigs were exposed to the same antigen. After three minutes, as the expiration time was prolonged and the respiratory resistance increased, the immunoreactivity in the trachea and the major bronchus was significantly higher than the pre-exposure levels. After six hours, however, they returned to the original levels except in the lower lung where the level was constant throughout the respiratory change. As described above, the possibility of controlling airway constriction by VIPergic nerve in immediate-type allergic reactions is suggested by our findings.

Amino Acid Sequence↗
PubMed1988

Differences in composition of sweat induced by thermal exposure and by running exercise.

To determine the differences in sweat composition between sweat induced by thermal stress alone and that induced by physical exercise, seven young healthy men first sat in a hot room and then performed running exercise. A 20-minute stay in a climate chamber at 40 degrees C resulted in a 5% reduction in body weight. The same body weight loss was induced by running exercise. Both sodium and chloride concentrations were much lower in the sweat induced by thermal exposure than that induced by the running exercise (p less than 0.01), while urea nitrogen and creatinine concentrations were significantly higher after thermal exposure than after the running exercise (p less than 0.01). Potassium concentrations did not differ significantly with either procedure. These findings suggest that sweat composition varies with the kind of induction and that more salt seems to be lost through exercise-induced sweating than by just sitting in a hot environment.

Adult↗