Biomedical subjects

M Koide

Publications and source records attributed to M Koide.

At least 127 records · Page 7Linked to original sources

PubMed1993

A new type of biomaterial for artificial skin: dehydrothermally cross-linked composites of fibrillar and denatured collagens.

A new type of biomaterial for artificial skin was developed as a form of sponge by combining fibrillar collagen (F-collagen) with gelatin. The sponge was physically and metabolically stabilized by introducing dehydrothermal cross links. To get the final product, various conditions in the preparation of sponges were evaluated by in vitro cellular responses and in vivo tissue reactions. Fibroblasts placed on a sponge of gelatin attached themselves to it, migrated well into the sponge, and remained inside it for at least 7 days. However, sponges of gelatin showed structural instability for hydrolytic degradation by the cells. Most fibroblasts appeared not to penetrate into the interior of a sponge of F-collagen but to remain on its surface when fibroblasts were placed on the sponge, suggesting poor attraction of F-collagen toward cells. Implantation experiments of sponges of F-collagen revealed an intense infiltration of neutrophils into the sponge, indicating F-collagen as an inducer of the inflammatory reaction. These aggravating characters of F-collagen sponges were greatly improved by blending gelatin with F-collagen. The new type of collagen-based biomaterials developed in the present study is expected to become a useful matrix substance for artificial skin.

Animals↗

PubMed1993

Effect of islet hormones on secretin-stimulated exocrine secretion in isolated perfused rat pancreas.

To clarify the effect of islet hormones on pancreatic ductular cell function, we measured the exocrine secretion elicited by 10 pM secretin in the presence or absence of islet hormones using an isolated perfused rat pancreas model. Insulin significantly increased secretin-stimulated pancreatic juice secretion, but not protein secretion. The potentiating effect of insulin on pancreatic juice secretion was concentration-dependent, and the maximal effect was observed with 1 microM insulin. Ouabain, a specific Na+,K(+)-ATPase inhibitor, caused concentration-dependent inhibition of the potentiating effect of insulin without affecting secretin action. Glucagon (100 nM) significantly inhibited secretin-stimulated pancreatic juice secretion and also tended to inhibit protein secretion. A somatostatin analog, SMS 201-995 (10 nM) significantly inhibited both the pancreatic juice and protein secretion stimulated by secretin. The inhibitory effect of SMS 201-995 was concentration-dependent and was maximal at 1-10 nM. These results demonstrate that insulin potentiates the secretory response to secretin, at least partly by increasing Na+,K(+)-ATPase activity, whereas glucagon and somatostatin inhibit this response. Thus, pancreatic islet hormones regulate the secretory function of pancreatic ductular and centroacinar cells.

Animals↗

PubMed1993

Role of endogenous bile on basal and postprandial CCK release in humans.

The role of intraduodenal bile in regulation of plasma cholecystokinin (CCK) levels were investigated in patients with obstructive jaundice under external bile diversion and under physiological bile flow into the duodenum by internal bile drainage. Basal plasma CCK levels determined by a specific and sensitive bioassay in patients under external bile drainage (2.2 +/- 0.2 pmol/liter; mean +/- SE) were significantly higher than those in control subjects (1.0 +/- 0.3 pmol/liter). In control subjects, the peak CCK response (6.2 +/- 0.7 pmol/liter) to a test meal was seen at 45 min, whereas that in patients under external bile drainage, it was seen at 20 min after a test meal (17.6 +/- 3.2 pmol/liter; P < 0.01 vs controls). After peak response, plasma CCK levels in controls gradually decreased, but remained significantly elevated during a 3-hr observation period. In patients under bile diversion, the test meal caused a prompt plasma CCK peak, with a transient fall followed by a continuous rise until 180 min postprandially. In six patients, external bile diversion was changed to internal biliary drainage with a stent tube within two weeks to maintain physiological bile flow into the duodenum. Internal bile drainage normalized basal (0.9 +/- 0.2 pmol/liter) as well as meal-stimulated CCK release (peak value: 5.0 +/- 0.8 pmol/liter). These results demonstrate that endogenous bile exerts tonic inhibition on basal and postprandial plasma CCK levels in humans.

Adenoma, Bile Duct↗

PubMed1993

In vitro inhibitory effect of somatostatin on secretin action in exocrine pancreas of rats.

BACKGROUND: Exocrine pancreatic function is influenced by pancreatic islet hormones. Although the existence of somatostatin receptors has been shown on pancreatic acinar cells, the in vitro effect of somatostatin on exocrine secretory function has not been established. METHODS: Using isolated rat pancreatic acini, the effect of somatostatin analog SMS 201-995 (SMS) and somatostatin 14 (S-14) on amylase release, cyclic adenosine monophosphate (cAMP) production, and hormone binding were determined. RESULTS: SMS inhibited the potentiating effect of secretin on amylase response to cholecystokinin octapeptide (CCK-8) in a concentration-dependent manner. The inhibitory effects of SMS and S-14 were similar on a molar basis and were observed when vasoactive intestinal polypeptide (VIP) but not 8bromoadenosine 3':5' cyclic monophosphate was used instead of secretin and when carbachol, bombesin, A23187, and 12-O-tetradecanoylphorbol 13-acetate were used instead of CCK-8. SMS inhibited secretin-induced cAMP production, and the dose-inhibition curve for cAMP was similar to that for amylase release. SMS had no influence on 125I-secretin and 125I-VIP binding. CONCLUSIONS: Somatostatin acts directly on acinar cells and inhibits secretin potentiation of secretory response in part by inhibiting secretin-induced cAMP production.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed1993

Hemodynamic mechanisms of the antianginal action of a novel vasodilator FK409 in dynamic exercise-induced angina.

FK409 is a novel vasodilator with a unique chemical structure. We wished to elucidate the mechanisms of antianginal action of FK409 in dynamic exercise-induced angina. Twelve patients with stable effort angina pectoris were studied before and after a single 40-mg oral dose of FK409. Chest pain was induced in all of 12 patients during the control multistage bicycle ergometer exercise. After FK409 administration, the same workload did not induce chest pain in 6 patients. The ST segment at peak exercise showed less severe depression from 0.15 +/- 0.02 to 0.05 +/- 0.01 mV (p < 0.001). Left ventricular (LV) filling estimated by the Doppler method was reduced, and pulmonary artery wedge pressure decreased significantly (p < 0.001) throughout exercise testing after FK409. Myocardial oxygen uptake and coronary sinus flow throughout exercise testing decreased significantly (p < 0.05) after FK409 administration. The results of the present study demonstrate that decrease in myocardial oxygen demand may be caused by pre- and afterload reduction and that it could be a major mechanism of the antianginal action of FK409. However, other mechanisms such as redistribution of coronary blood flow to the subendocardium, direct dilatation of the stenotic parts of the epicardial arteries, and an increase in collateral blood flow should be considered additional possible mechanisms of the antianginal action of FK409.

Aged↗

PubMed1993

Involvement of endogenous cholecystokinin in the development of acute pancreatitis induced by closed duodenal loop.

Involvement of endogenous cholecystokinin (CCK) in the development of acute pancreatitis induced in rats by closed duodenal loop (CDL) was examined, and the effects of the potent and specific CCK receptor antagonist loxiglumide on this model of acute pancreatitis were evaluated. Plasma CCK bioactivity was markedly elevated 3 and 6 h after onset of acute pancreatitis. A single subcutaneous injection of 50 mg/kg body wt of loxiglumide 30 min before the induction of acute pancreatitis completely eliminated the hypercholecystokinemia. Loxiglumide given 3 h after the induction of acute pancreatitis suppressed plasma CCK bioactivity, which had risen up to 30-fold over basal value (0 h) at 3 h, to nearly the basal level. Loxiglumide pretreatment, in addition, significantly prevented the rise in serum amylase and lipase activity, as well as the increase in ascitic volume. It also ameliorated histological alterations of hemorrhagic and necrotizing pancreatitis. Reduction of plasma CCK bioactivity by loxiglumide after the onset of pancreatitis slowed the rate of progression of pancreatitis. However, pancreatic wet weight and cellular infiltration were not significantly influenced by loxiglumide treatment. These observations suggest that endogenous CCK is not involved in the initiation of acute hemorrhagic and necrotizing pancreatitis induced by CDL, but is involved in the development of pancreatitis in this model.

Acute Disease↗

PubMed1993

[Study of Legionella pneumophila detection by two step polymerase chain reaction].

We studied the usefulness of two sets of primers in macrophage infectivity potentiator gene sequence of Legionella pneumophila. PCR by 1st step primers produced 649 bp DNA bands and 2nd step primers 489 bp DNA bands. Two step PCR by these primers produced 489 bp DNA bands specific for L. pneumophila. Two step PCR detected 10 fg of pure DNA extracted from L. pneumophila, Philadelphia-1 strain. PCR sensitivity by these primers was superior to former primers reported by us using intratracheal aspirates collected from the patient with L. pneumophila serogroup 2 pneumonia.

Base Sequence↗

PubMed1993

Detection of Legionella spp. in cooling tower water by the polymerase chain reaction method.

The presence of Legionella spp. in cooling tower water was investigated by using the polymerase chain reaction. Total Legionella spp. detection was performed with 20-mer 5S rRNA complementary DNA sequence primers, and specific Legionella pneumophila detection was performed with 20-mer and then 21-mer macrophage infectivity potentiator gene sequence primers. Of 27 cooling tower water samples, 25 were positive for Legionella spp., and 14 of these contained L. pneumophila.

Bacteriological Techniques↗

PubMed1993

Differential effects of proteinase inhibitor camostat on exocrine pancreas in fed and fasted rats.

Effects of an oral dose of the synthetic trypsin inhibitor camostat on pancreatic exocrine function were examined in rats that were either fasted from 12 h before feeding camostat to the end of experiments or fed ad libitum. Camostat (100 mg/kg body wt) caused significant increases in plasma cholecystokinin bioactivity (peak 13.4 +/- 2.0 pM at 30 min for fasted rats vs. 16.6 +/- 1.7 pM at 2 h for fed rats; not significant) and pancreatic exocrine secretion. In fed rats, but not in fasted rats, significant increases in pancreatic exocrine secretion were observed again at 12 h after a single oral dose of camostat (juice flow 10.3 +/- 0.4 microliters/20 min in fasted rats vs. 175.5 +/- 17.8 microliters/20 min in fed rats; P < 0.001), although pancreatic juice flow in fed and fasted control rats was nearly the same. When the pancreata from camostat-pretreated rats were isolated and perfused, the early effects of camostat on pancreatic exocrine secretion were abolished, whereas the late effects (12 h postfeeding) in fed rats were still observed (juice flow 33.7 +/- 3.4 microliters/20 min vs. control 2.8 +/- 0.4 microliters/20 min; P < 0.001). Thus, in addition to humoral and neural factors, persistent functional changes might have occurred in the pancreas of the fed camostat-pretreated rats. These present results indicate that oral camostat induces two different effects, immediate and delayed, on pancreatic exocrine secretory function. Camostat exerts its immediate effects in both fed and fasted rats, whereas delayed effects were induced only in fed rats.

Administration, Oral↗

PubMed1993

Abnormal postexercise systolic blood pressure response is a good indicator of impaired left ventricular filling during supine cycle ergometer exercise in patients with coronary artery disease.

To determine whether the postexercise systolic blood pressure (SBP) response is a useful marker of left ventricular filling abnormalities, supine leg exercise testing was conducted in 14 control subjects and 70 patients with coronary artery disease (CAD). An abnormal postexercise SBP response (the ratio of SBP after 3 min of recovery to the peak exercise SBP) was defined as 0.85 or more, which represented the cutoff point with the highest sensitivity and specificity for prediction of pulmonary artery wedge pressure (PAWP) of at least 20 mmHg at peak exercise in CAD patients. There was a significant difference between the SBP ratios of the two groups (Control, 0.72 +/- 0.05; CAD, 0.86 +/- 0.13; p < 0.01). There was no significant difference between the PAWP of the two groups at rest, but the PAWP at peak exercise was significantly higher in the CAD group (20.2 +/- 8.9 mmHg) than in the control group (11.5 +/- 4.0 mmHg)(p < 0.01). PAWP at peak exercise was > or = 20 mmHg in 35 (50%) of the 70 CAD subjects. The SBP ratio was significantly correlated with PAWP at peak exercise (r = 0.67, p < 0.01) in the CAD group, but not in the control group. An SBP ratio of > or = 0.85 showed a sensitivity of 80% and a specificity of 80% for predicting a peak exercise PAWP of > or = 20 mmHg in CAD patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

[Inhibitory effect of somatostatin analogue, SMS 201-995, on secretin-stimulated exocrine secretion in isolated perfused rat pancreas].

In order to clarify the effect of somatostatin of the ductal secretion of the exocrine pancreas, we measured pancreatic juice and protein secretion stimulated with 10 pM secretin and/or 10 pM cholecystokinin (CCK) in the presence or absence of somatostatin analogue, SMS 201-995 (SMS) utilizing the isolated perfused pancreas of rats. SMS significantly inhibited both pancreatic juice flow and protein output elicited by 10 pM secretin without affecting basal secretion. The inhibitory effect of SMS was dose-dependent and maximal inhibition was observed with 1-10 nM. Half-inhibitory dose of SMS for juice secretion was 140 pM. Because CCK is thought to potentiate secretin action on the ductal system, we examined the effect of SMS on pancreatic secretory response to 10 pM secretin in combination with 10 pM CCK. In the experimental system we used, the amounts of pancreatic juice and protein secreted during a 30-min stimulation with secretin and CCK were additive. SMS inhibited both pancreatic juice and protein secretion to the level comparable with that obtained with either stimulus and SMS. SMS had no effect on CCK-stimulated pancreatic juice secretion but significantly inhibited protein output. The present study demonstrated, therefore, that SMS inhibits ductal secretion in response to physiological concentration of secretin.

Animals↗

PubMed1993

[A case report: surgical repair of bilateral coronary artery-pulmonary artery fistula associated with mitral regurgitation, tricuspid regurgitation and severe renal dysfunction].

The patient was a 72-year-old female who was admitted with evaluation of dyspnea on effort. On cardiac catheterization, coronary angiography showed the fistula from both RCA and LAD to the pulmonary artery and L-R shunt ratio was 37.4%, and MR and TR were found. The preoperative examination showed renal dysfunction, BUN: 61.6 mg/ml, Cr: 21. mg/ml, 24 hr Ccr: 15.2 ml/min. At the operation, the fistula was closed from the inside of the pulmonary artery and MVR (27 SJM) and TAP (Kay-Reed method) were performed associated with the intra-operative hemodialysis. The peritoneal dialysis was used for 9 days after the operation. The hemodynamics and the urination were well controlled. A successful surgical repair of bilateral coronary artery-pulmonary artery fistula associated with valvular disease and severe renal dysfunction was reported.

Aged↗

PubMed1993

[Plasma cholecystokinin levels in rats with pancreatic insufficiency induced by intra ductal injection of oleic acid].

Plasma cholecystokinin (CCK) levels in rats with pancreatic insufficiency induced by a single injection of 50 microliters oleic acid into the pancreatic duct were determined by a sensitive and specific bioassay using the isolated rat pancreatic acini. Treatment with oleic acid significantly decreased pancreatic wet weight within 7 days, which lasted until the end of observation (56 days). Histologic examination revealed the destruction of acinar cells and the epithelium of intra- and interlobular ducts. Plasma CCK bioactivity was significantly increased from the pre-treatment values of 0.8 +/- 0.1pM to 5.1 +/- 1.4pM at 24h after oleic acid treatment. After this peak, plasma CCK levels gradually decreased. Even after 56 days, however, plasma CCK levels in oleic acid-treated rats were significantly high compared with those in control rats. In the present study, plasma CCK levels in rats with chronic pancreatitis did not correlate with the progress of pancreatic insufficiency.

Animals↗

PubMed1993

[Measurement of cardiac output by Doppler echocardiography: clinical validation in pediatric patients after open heart surgery].

We compared the cardiac output obtained by pulsed Doppler echocardiography (COPW) with simultaneous thermodilution measurements (COTD) in 13 children for 33 times after open heart surgery. Good correlation (r = 0.84, slope = 1.15) of cardiac output was obtained when direct measurements of aortic diameter during operation were used in the calculations. Cardiac output was overestimated (r = 0.89, slope = 1.42) when 2 DE measurements of aortic diameter were used. Nineteen measurements of 8 VSD patients revealed good correlation (r = 0.89, slope 0.85) using direct measurement of aortic diameter, whereas 14 measurements of TOF patients showed somewhat overestimation of cardiac output (r = 0.90, slope = 1.31). In serial determinations, percent change change in COPW well correlated with COTD (r = 0.75, slope = 1.08). We conclude that accurate cardiac output can be obtained by pulsed Doppler echocardiography after pediatric cardiac surgery by measuring aortic diameter directly in operation room. Accuracy in percent change in cardiac output proved that COPW is useful especially in hemodynamically unstable patients after pediatric cardiac surgery.

Age Factors↗

PubMed1993

[Biventricular repair with a modified Glenn shunt for the hypoplastic right ventricle].

Between 1982 and 1990, 14 patients with small right ventricle underwent biventricular repair with a modified Glenn shunt. The patients consisted of 8 cases of pulmonary atresia and intact ventricular septum, 2 with pulmonary stenosis and intact ventricular septum, 3 with tetralogy of Fallot, 1 with pulmonary atresia and straddling tricuspid valve. Nine patients had one or more prior preliminary palliative procedures. Repairs consisted of a modified Glenn shunt and closure of the intracardiac and extracardiac shunt, with right ventricular outflow reconstruction in 13, and pulmonary valvotomy in 1. In nine patients superior vena cava was not ligated. There was one operative death (7%). Preoperative RVEDV ranged from 19 to 70% of normal with a mean of 36.1% of normal. Preoperative pulmonary resistance ranged from 1.6 to 5.3 unit with a mean of 2.8 unit. Preoperative PA index ranged from 102 to 444 mm2/m2 with a mean of 234.3 mm2/m2. No patients died later. Follow-up 2 to 9 year after operation showed that 9 patients were in the New York Heart Association class I and 4 were in class II. Our experience shows that this procedure can be safely done for patients, who have hypoplastic right ventricle smaller than 40% of normal and are not candidate for Fontan procedure because of high pulmonary vascular resistance and inadequate size of pulmonary artery. In this procedure a modified Glenn shunt without ligation of SVC may effectively reduce the volume overload on the right ventricle.

Adolescent↗

PubMed1993

Anatomic correction of atrioventricular discordance.

Between June 1989 and September 1991, 11 patients underwent anatomic correction of atrioventricular discordance. Their ages at operation ranged from 1 to 11 years (mean 6.7 years) and their weights ranged from 7.1 to 31.8 kg (mean 19.1 kg). Atrial situs was solitus in nine and inversus in two patients. Ventriculoarterial connection was discordant in five and was double-outlet right ventricle in six patients. Associated congenital heart defects were seen in all patients, including 10 with ventricular septal defect, eight with atrial septal defect, nine with pulmonary stenosis or pulmonary atresia, seven with tricuspid regurgitation, and four with mitral regurgitation. Five patients had prior Blalock-Taussig shunts. One patient with an intact ventricular septum had repeated pulmonary banding. Anatomic correction consisted of the Senning and Rastelli procedures in three, the Mustard and Rastelli procedures in five, the Senning and arterial switch operations in two, and the Mustard and arterial switch operations in one patient. In addition, mitral valvuloplasty or valvular annuloplasty was performed in three patients. We did not encounter kinking or torsion of the translocated coronary arteries in our three patients with the arterial switch operation. There was one surgical death. The other patients pursued satisfactory postoperative courses (mean follow-up period of 12.6 months). We recommend that anatomic correction for atrioventricular discordance should be indicated, especially in patients with any sign of systemic right ventricular dysfunction.

Cardiac Surgical Procedures↗

PubMed1993

[Effect of cholecystokinin and secretin on insulin binding to rat pancreatic acini and pancreatic cancer cell line AR42J cells].

In order to clarify the interaction of hormones which exert various effects on the exocrine pancreas, we investigated the effect of cholecystokinin (CCK) and secretin on subsequent insulin binding to pancreatic acini and cultured AR42J cells derived from azaserine-induced acinar cell carcinoma of the pancreas. CCK at concentrations of 100pM-10nM inhibited subsequent 125I-insulin binding to pancreatic acini. 12-O-tetradecanoylphorbol 13-acetate (TPA) inhibited 125I-insulin binding whereas A23187 had little effect, suggesting that the inhibitory effect of CCK is mediated by protein kinase C. On the other hand, 100pM-10nM secretin had no effect on subsequent 125I-insulin binding to pancreatic acini, although higher concentrations of forskolin and 8 bromoadenosine 3', 5'-cyclic monophosphate inhibited 125I-insulin binding. In addition, secretin exerted no potentiating effect on the inhibitory effect of CCK on 125I-insulin binding to pancreatic acini. Based on these results, we further investigated the effect of CCK and TPA on subsequent 125I-insulin binding to AR42J cells. In this carcinoma cell line, inhibitory effect of CCK and TPA on insulin binding was completely abolished. The present results suggest, therefore, that hormonal interaction may play an important role in the regulation of exocrine pancreatic function including acinar cell growth.

Animals↗

PubMed1992

Involvement of MAP kinase activators in angiotensin II-induced activation of MAP kinases in cultured vascular smooth muscle cells.

In cultured vascular smooth muscle cells (VSMC) angiotensin II (ang II) induces tyrosine and serine/threonine phosphorylation and activation of two mitogen-activated protein (MAP) kinases. When extracts of ang II-stimulated VSMC were fractionated by Mono Q anion-exchange column chromatography, three peaks of the activities which in vitro activate inactive MAP kinases were detected. These MAP kinase activator activities were not detected in extracts of unstimulated VSMC. In vitro activation of MAP kinases by the MAP kinase activators was accompanied by tyrosine and serine/threonine phosphorylation of MAP kinases. These results suggest that the MAP kinase activators are involved in the ang II-induced phosphorylation and activation of MAP kinases in VSMC.

Angiotensin II↗