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Biomedical subjects

Y Uchida

Publications and source records attributed to Y Uchida.

At least 469 records · Page 26Linked to original sources
PubMed1991

Multiple mechanisms of bronchoconstrictive responses to endothelin-1.

We investigated the mechanism of the endothelin-1 (ET-1)-induced bronchoconstriction of guinea pig tracheal smooth muscles. ET-1 contracted the tracheas in a dose-dependent manner. A combination of FPL55712 (leukotriene antagonist), diphenhydramine (histamine antagonist), and indomethacin (cyclooxygenase inhibitor) shifted the dose-response curve of ET-1 to the right and suppressed the maximal constriction. Azelastine, an antiallergic agent, exerted essentially similar results. The present data suggest that ET-1 constricts the airway smooth muscles not only by direct action on the tracheal smooth muscles but also by indirect action mediated through production of various chemical mediators in cells other than muscles.

Animals↗
PubMed1991

Penetration of lysophosphatidylcholine into the dermis.

The ability of Lysophosphatidylcholine (LPC) to penetrate into the dermis and its degradation were investigated in vivo using hairless rats. Phosphatidylcholine (PC) was used as a control. Radioactively labelled LPC and PC were applied on the surface of skin, and the radioactivities of the epidermis and dermis were measured at 8, 24, and 48 hours. The recoveries of radioactive materials of LPC and PC within the area of epidermis and dermis at 8 hours were 0.21% and 0.25%; at 24 hours, 0.68% and 0.31%; and at 48 hours, 0.42% and 0.92%. No radioactivity was detected in serum. The radioactive substances which had penetrated were identified as LPC, PC, diglycerides, and free fatty acids. It was also found that topical application of LPC did not change the structure of skin as seen by microscopical examination. These findings indicate that a small amount of LPC can penetrate without the damaging skin structure and is enzymatically degraded into several lipids. Since LPC has bactericidal and antiviral activity, this substance could be an useful agent for dermatological use.

Animals↗
PubMed1991

Prevalence of hepatitis B virus infection markers among factory workers in Beijing, China.

Nearly 1,000 serum samples were obtained from apparently healthy workers of both sexes in various factories in Beijing during 1988-1989 and were examined for hepatitis B virus infection markers by radioimmunoassay. The overall prevalence (all ages and both sexes combined) of cases positive for HBsAg, anti-HBs and anti-HBc were 3.7%, 36.6% and 37.7%, respectively and the rate of those negative to any of the three markers studied was 56.1%. The infection rate was lower than the values reported early in the 1980s for Beijing populations or the values for populations in other parts of China.

Adolescent↗
PubMed1991

Structure-activity relationships of rat neuromedin U for smooth muscle contraction.

Rat neuromedin U (r-NMU) and its fragment peptide amides were synthesized by solid-phase methodology. Using a chicken crop smooth muscle contraction assay, the potency of r-NMU and its fragments relative to porcine neuromedin U-8 (p-NMU-8) was r-NMU: 10.25 +/- 2.88, r-NMU (6-23): 8.01 +/- 1.04, r-NMU (10-23): 2.76 +/- 0.46, r-NMU (13-23): 2.81 +/- 0.52, and r-NMU (16-23): 0.88 +/- 0.19, respectively. Two heptapeptides, r-NMU (17-23) and r-NMU (16-22), had a relative potency of 0.61 and 0.03 respectively, and elicited maximal contraction at a dose of 10 microM to a similar degree to p-NMU-8. The other shorter C-terminal fragments did not elicit the maximal contraction or any activity. In a rat uterus contraction assay, r-NMU (13-23), but not r-NMU (16-23), at a dose of 4 nM retained as high a stimulatory activity as r-NMU itself. r-NMU (17-22) was the smallest peptide fragment to elicit the maximal sustained contraction at 10 microM. These results indicate that the amino acid sequence Phe-Leu-Phe-Arg-Pro-Arg, corresponding to positions 17 to 22 of r-NMU, may be essential for contractile activity. N-terminal peptide segments Tyr-Gln-Gly-Pro corresponding to positions 6 to 9, and Ser-Gly-Gly corresponding to positions 13 to 15, appear to be of special importance for potent activity.

Amino Acid Sequence↗
PubMed1991

Agonistic and antagonistic activities of neuromedin U-8 analogs substituted with glycine or D-amino acid on contractile activity of chicken crop smooth muscle preparations.

To study the structure-activity relationships of neuromedin U-8 (NMU-8) (H-Tyr-Phe-Leu-Phe-Arg-Pro-Arg-Asn-NH2) and to develop a NMU-8 antagonist, twenty-three NMU-8 analogs substituted with Gly or the corresponding D-amino acid(s) at positions 1-8 were synthesized by solid-phase techniques. On isolated chicken crop preparations, the contractile activity of the synthetic NMU-8 analogs was compared with that of NMU-8 and their antagonistic activity was assayed against NMU-8. The replacement of Phe2, Phe4, Arg5, Pro6, Arg7 or Asn8 with Gly brought about a drastic decrease of the agonistic activities. Substitution of the corresponding D-amino acid residue for Phe2, Phe4, Arg5, Pro6 or Asn8 caused a marked decrease of the agonistic activities, while the replacement of Tyr1 with D-form enhanced the activity. It was further revealed that [D-Pro6]-NMU-8 and [D-Leu3, D-Pro6]-NMU-8 exerted a non-competitive antagonistic activity against NMU-8 with x values of 5.22 +/- 0.12 and 5.34 +/- 0.09, respectively. [D-Phe2, D-Pro6]-NMU-8, [D-Arg5, D-Pro6]-NMU-8 and [D-Pro6, D-Asn8]-NMU-8 showed a very weak antagonism. The results indicated that 1) the side chain of each amino acid at positions 2, 4, 5, 6, 7 and 8 of NMU-8 is of relative importance for the expression of the contractile activity, and 2) [D-Pro6]-NMU-8 and its four analogs acted as an antagonist against NMU-8.

Amino Acid Sequence↗
PubMed1991

Analysis of perioperative ventricular arrhythmias in valvular heart diseases by Holter ECG recording.

Seventy-one consecutive patients undergoing cardiac surgery for acquired valvular diseases were analyzed to determine the incidence of and the predisposing factors to postoperative ventricular arrhythmias. We recorded the Holter ECGs before (pre-op), and within 24h (op-day) and 4 to 10 weeks after operation (post-op) and determined the frequency of ventricular arrhythmias and the degree according to the Lown grade. The relationship between the op-day ventricular arrhythmias and clinical, hemodynamic, operative or postoperative variables was examined. The operation included mitral valve replacement or open mitral commissurotomy (49 patients, group M), aortic valve replacement (12 patients, group A) and a combined mitral and aortic operation (10 patients, group A + M). In all groups, the frequency and the degree of ventricular arrhythmias increased at the op-day and decreased at the post-op period approximately to the pre-op level. The frequency and Lown grade of the 3 groups were similar in each of the pre-op, the op-day and the post-op periods. The frequency and Lown grade of the op-day ventricular arrhythmias increased with increases in the arrhythmia frequency and Lown grade at the pre-op period, and in patients with left ventricular (LV) dysfunction at the post-op period, as evidence by an increased LV volume and decreased ejection fraction on echocardiograms. Furthermore, the frequency of ventricular premature contractions in the op-day was significantly less when a cardioplegia solution containing magnesium was used than in the case of a cardioplegia solution without magnesium. The op-day ventricular arrhythmias showed no significant relation to extracorporeal circulation time, aortic cross-clamping time, the antiarrhythmic drugs used and the op-day serum levels of K and CK-MB.

Adult↗
PubMed1991

Vascularised fibular graft for congenital pseudarthrosis of the tibia. Long-term results.

Five children with congenital pseudarthrosis of the tibia treated by free vascularised fibular grafts were followed up until skeletal maturity. The ipsilateral fibula was used in four cases, the contralateral fibula in one. All our cases achieved bone union, but leg length discrepancy, atrophy of the foot and ankle stiffness were frequent complications, due perhaps to the many previous operations. Vascularised fibular grafting might achieve better results if it were done as the primary procedure.

Atrophy↗
PubMed1991

Percutaneous fiberoptic cardioscopy of the left ventricle.

The feasibility of percutaneous transluminal cardioscopy of the left ventricle was examined in 35 patients with or without various heart diseases. A guiding balloon catheter (7 or 9 French) was introduced through the right femoral artery into the left ventricle. The balloon was inflated, and a fiberscope (1.6 or 4.3 French) was advanced to the distal tip of the catheter. The balloon was then manipulated against the portion of the ventricle targeted for examination, and heparinized saline (10 U/ml) at body temperature was infused through the catheter at 5 ml/sec for 3 to 6 sec. The images were recorded on videotape and 16 mm cinefilm. In 4 patients without demonstrable heart disease, the endocardial surface of the left ventricle was brown and the trabeculae became prominent during systole. The chordae connected to the mitral leaflets were white. In 3 of 5 patients with dilated cardiomyopathy, the endocardium was light yellow with thin trabeculae which barely contracted during systole. The endocardium was red or reddish-brown in 3 patients with acute myocarditis. In patients with rheumatic mitral stenosis white patches were scattered on the endocardial surface. In 7 of 8 patients the akinetic or dyskinetic segments representing prior infarctions were white. No complications other than transient ventricular arrhythmias were noted. We conclude that percutaneous fiberscopic imaging with a guiding balloon catheter is feasible and safe, and yields highly detailed images of the endocardium.

Acute Disease↗
PubMed1991

Enzyme-histochemical study on the fine distribution of the intramural lymphatics at the ileocecal junction of the monkey intestine.

The fine distribution of the intramural lymphatics at the ileocecal junction of the monkey intestine, especially in the lamina propria of the ileocecal valve, was examined by light and electron microscopy using enzyme-histochemical staining. The distinction between the lymphatics and the blood vessels was made by light microscopy on cold glycol methacrylate resin (JB-4) sections using 5'-nucleotidase (5'-Nase)-alkaline phosphatase (ALPase) double staining. The lymphatics were found to show strong 5'-Nase activity and to comprise irregularly shaped vessels or spaces. The central lymphatic vessels (central lacteals) in low villi were seen to lie deep within the ALPase-positive subepithelial capillary network. In the ileum side of the ileocecal junction, the 5'-Nase-positive lymphatics were seen both in the superficial layer and the deep layer of the lamina propria. On the contrary, in the cecum side the mucosal lymphatics were less numerous in the superficial layer and were distributed mainly in the deep layer near the lamina muscularis mucosae. These lymphatics ran through the lamina muscularis and merged into the lymphatic network in the submucosa. The submucosal lymphatics communicated with each other at the ileocecal junction and formed a well-developed network. Collecting lymphatics with valves were also seen near the tunica muscularis (sphincter muscle) in the deep submucosa. These lymphatics traversed the muscle layer and drained into the subserosal lymphatics.

5'-Nucleotidase↗
PubMed1991

Evidence for a direct adverse reaction of neuroleptics in self-induced water intoxication of psychiatric patients.

A mentally retarded patient who developed polydipsia and hyponatremia following the long-term use of neuroleptics is described. Before the investigation, he was treated with a combination of five drugs: diazepam, propericiazine, carbamazepine, lithium carbonate and trihexyphenidyl. The treatment was switched to diazepam alone; to propericiazine, trihexyphenidyl and diazepam; to carbamazepine and diazepam; and finally to lithium carbonate with diazepam. Under the five drug treatment protocols, his weight gains during the day were monitored, every day as an index of the water he drank in the day time. The combination of the five drugs caused the greatest weight differences per day and the other drug regimens, except diazepam alone, seemed to increase the weight differences to some extent. These findings indicate that a drug combination such as the neuroleptics, lithium and carbamazepine used for emotional stabilization must be carefully monitored to avoid the induction of compulsive drinking.

Adult↗
PubMed1991

[Endothelin-1 induced relaxation of guinea pig trachea after an anaphylactic reaction].

Endothelin-1 (ET-1), one of the most potent constrictors of airway smooth muscles, is reported to act on such inflammatory cells as mast cells and release several chemical mediators. We observed a transient relaxation response to ET-1 after an anaphylactic constriction of guinea pig tracheal smooth muscle. The guinea pig was actively sensitized with ovalbumin, and the tracheal strip was challenged with ovalbumin in vitro. ET-1 induced a transient relaxation followed by a constriction of the tracheal strip. The potency of the relaxation induced by 10(-9) M of ET-1 was 16.0 +/- 1.3%, compared to the response to isoproterenol (2 x 10(-5) M), and the duration of the relaxation was 7.2 +/- 0.7 minutes. Indomethacin (10(-6) M) had no effect on the response, indicated that prostaglandins have no relation. Mechanical denudation of the tracheal epithelium did not reduce the relaxation, but rather augmented it. These results indicate that ET-1 induces a relaxation, associated with a relaxation factor from non-epithelial tissue.

Anaphylaxis↗
PubMed1991

[Long-term hemodialysis and changes in variables of coagulation and fibrinolysis].

The development of hemodialysis treatment has remarkably improved the prognosis of chronic hemodialysis (HD) patients. However, as the patient's survival time is prolonged, vascular damages due to the abnormalities of calcium and lipid metabolism and hypertension has become the important complications in HD patients. In addition to coagulation and fibrinolysis, vascular endothelial function has been pursued to clarify the pathogenesis for occurrence of thrombosis in HD patients with more than ten years' duration. Twenty-two HD patients including twelve of less than ten years' duration and ten of more than ten years' were subjected to this study. Twelve healthy controls were also involved in this study. Fibrinopeptide A (FPA) and thrombin-antithrombin III complex (TAT) as indexes of coagulation, antithrombin III (AT III) as an index of coagulation inhibitor and D-dimer as an index of fibrinolysis were measured. A special attention has been focused in changes in the levels of tissue plasminogen activator (t-PA) activity and antigen and plasminogen activator inhibitor-1 (PAI-1) as indexes of fibrinolysis capacity, representing parameters of vascular endothelial functions. Levels of FPA, TAT and D-dimer were significantly higher in HD patients when compared with those in healthy controls. In particular, levels of FPA were significantly higher in HD patients with more than ten years' duration as compared to those in HD patients with less than ten years'. AT III values were significantly lower in HD patients with more than ten years' duration than those in healthy controls. T-PA activity and antigen levels were significantly lower in HD patients than those in healthy controls. T-PA activity levels were lower in HD patients with more than ten years' duration than those in HD patients with less than ten years'. Among HD patients, a significant negative correlation was found between t-PA activity and hemodialysis duration. PAI-1 values in HD patients were not significantly differ from those in healthy controls. These results suggest that in spite of increased coagulability, fibrinolytic capacity of vascular endothelium decreased in HD patients, and that the incidence is accelerated as hemodialysis duration is prolonged. Therefore, it is concluded that long-term HD patients are in the state of a higher risk of thrombosis.

Adult↗
PubMed1991

[Blood flow measurement of brain tumor by 123I-IMP using 3-heads rotating gamma camera SPECT].

Using 3-heads rotating gamma camera SPECT system, regional blood flow was measured from the super-early image obtained 4 to 6 minutes after the intravenous injection of 123I-IMP on 11 patients with various brain tumors. Two cases of olfactory groove meningioma and malignant astrocytoma showed significantly high 123I-IMP uptake by the lesion visualized by MRI compared to the uptake by normal brain cortex on super-early image but 123I-IMP uptake by the tumor decreased on early image. In both cases, blood flow of the tumor measured from super-early image showed values much higher than those of normal brain cortex. It was thought that usual correction method based on early image did not correctly represent the blood flow of the lesion but that the present method based on super-early image could show the increase of blood flow of the tumor.

Adult↗
PubMed1991

Biliary excretion of bile acid conjugates in a hyperbilirubinemic mutant Sprague-Dawley rat.

The hepatic transport of bile acid conjugates was studied in the Eisai hyperbilirubinuria rat, a Sprague-Dawley mutant rat with conjugated hyperbilirubinemia. Serum bile acid levels were increased, bile acid-independent bile flow was decreased and biliary glutathione concentrations were markedly decreased in the Eisai hyperbilirubinuria rat. Biliary excretion of sulfobromophthalein was markedly impaired and almost no glutathione conjugate was excreted in the bile of the Eisai hyperbilirubinuria rat. Biliary excretion of lithocholate-3-O-glucuronide and lithocholate-3-sulfate in the Eisai hyperbilirubinuria rat was markedly delayed, whereas that of lithocholate was only slightly delayed. After [14C]chenodeoxycholate infusion (1 mumol/min/100 gm for 60 min), the increases in bile flow and biliary excretion of isotope in the Eisai hyperbilirubinuria rat were not so prominent as those observed in control rats, and the glucuronide of chenodeoxycholate, which constituted about 15% of biliary chenodeoxycholate in control rats, was not observed in the Eisai hyperbilirubinuria rat. Initial uptake of lithocholate and its glucuronide and sulfate by isolated hepatocytes was not impaired in the Eisai hyperbilirubinuria rat; the profiles of cytosolic bile acid binding proteins in Eisai hyperbilirubinuria rat liver were identical to those in control liver. These data indicate that the Eisai hyperbilirubinuria rat has excretory impairment of organic anions, bile acid glucuronide and sulfate and that it has characteristics very similar to those of the hyperbilirubinemic mutant Wistar rats TR- and GY.

Animals↗
PubMed1991

[A case of perforation of the metastatic site of lung carcinoma in the small bowel].

Metastasis of lung carcinoma in the small bowel is so extremely rare as there were 53 cases in total with small bowel metastasis from lung carcinoma reported in the past literature. A case of a 72-year-old man with unresectable lung carcinoma (squamous cell carcinoma) was reported, he had an acute perforation of the small bowel following intensive course of irradiation therapy for primary site. Emergency operation was performed, but he died of DIC (disseminated intravascular coagulation) 3 days after surgery.

Aged↗
PubMed1991

[A case of left atrial ball thrombus without mitral disease].

A 65-year-old man who had a left atrial ball thrombus without mitral disease is reported. Ultrasonic cardiogram gave this diagnosis. His ECG showed atrial fibrillation and severe bradycardia. Thrombus attached to the left appendage with short stalk was removed under extracorporeal circulation and a pacemaker (VVI mode) was implanted. Postoperative course was not eventful.

Aged↗
PubMed1991

[Extended left atriotomy by temporary division of the superior vena cava].

The extended left atriotomy which combine the standard approach with the superior approach by concomitant temporary division of the superior vena cava is a safe and useful method especially in the case of small atrium or in the case of having anatomically abnormal situation of the left atrium. The technical detail was introduced here, and it is a modification of that reported by Selle and Kyger. We used this technique in three cases. The first was corrected transposition of the great arteries which required prosthetic replacement of the left sided atrioventricular valve. The second and third cases were mitral valve insufficiency with small left atrium which were performed mitral annuloplasty and caspal repair. All three patients have done well without SVC stenosis and perioperative morbidity like arrhythmia or bleeding.

Heart Arrest, Induced↗