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Biomedical subjects

H Kikuchi

Publications and source records attributed to H Kikuchi.

At least 811 records · Page 45Linked to original sources
PubMed1984

Mechanism(s) of the hypotensive effect of synthetic 1-O-octadecyl-2-O-acetyl-glycero-3-phosphorylcholine.

The mechanism of the hypotensive effect of 1-O-octadecyl-2-O-acetyl-glycero-3-phosphorylcholine (C18- AGPC ) was examined. Synthetic C18- AGPC caused dose-dependent hypotension in conscious rats. The activity was almost the same in DOCA and renal hypertensive rats. This suggests that it is not a renin inhibitor. Hypotension also appeared in pithed rats. This suggests that the effect is not due to a central mechanism. Hypotension did not result from platelet aggregation or bronchial constriction. Since C18- AGPC suppressed not only the pressor response to noradrenaline but also to angiotensin II and vasopressin, and furthermore, did not disturb the dose-response curve of noradrenaline in the isolated aorta, the possibility of the agent being an alpha-adrenergic antagonist is ruled out. In the PGF2 alpha-contracted rat aorta. C18- AGPC caused marked vasodilation, which disappeared after removal of the endothelium. Perfusion pressure decreased in the blood-perfused rat hindquarters but not in the Tyrode solution-perfused ones. C18- AGPC induced a positive inotropic effect in isolated rat atrium. The hypotensive effect of synthetic C18- AGPC seems to be mainly due to endothelium-dependent vasodilation.

Adrenergic alpha-Antagonists↗
PubMed1984

Analytical isotachophoresis utilizing computer simulation. II. Assessment of optimum separation conditions for urinary trifluoroacetic acid metabolized from anaesthetic halothane.

Experimentally determined optimum separation conditions for a metabolite of anaesthetic halothane in urine, trifluoroacetic acid, were assessed by means of computer simulation of the isotachophoretic steady-state. The simulation confirmed that urinary acids and trifluoroacetic acid can be separated in the limited pH range of 3.5-3.7 buffered by beta-alanine, as far as the pH dependence of effective mobility is utilized. The separated fraction of the trifluoroacetic acid zone was identified by mass spectrometry. The simulated coefficient of the calibration curve agreed well with the observed value.

Computers↗
PubMed1984

In vitro protein synthesis using D-amino acids and its evolutionary significance.

The in vitro incorporations of D-Trp or -Ala into peptides were investigated using a crude system. Although none of aminoacylation to the former was observed under the present condition, the latter was utilized for peptide synthesis at the same rate as the opposite enantiomer. The results of analyzing the peptides showed that the peptides, which were synthesized with either D-, L- or DL-Ala as the substrate, were composed of mostly similar molecular size. The study of incorporations of radioisotopes (14C-D- and 3H-L-Ala) into peptides also indicated that D-Ala was by no means inferior to L-Ala for the substrate. Basing upon the present experiment, the evolutionary significance for utilizing D-amino acids is discussed.

Amino Acids↗
PubMed1984

Moyamoya disease associated with bilateral occlusion of the vertebral artery.

An unusual case of moyamoya disease associated with bilateral occlusion of the vertebral artery is reported. This case shows several embryologic collateral channels, which are typical of moyamoya disease, around the brainstem, that is, a transdural anastomosis between the superior cerebellar artery and the posterior meningeal artery, a leptomeningeal anastomosis between the superior cerebellar artery and the posterior inferior cerebellar artery, and moyamoyalike collateral vessels via primitive lateral anastomotic channels of Padget . Bilateral encephalomyosynangiosis (temporal muscle graft) were performed. Postoperatively, no ischemic attacks have developed for 6 years.

Adolescent↗
PubMed1984

Migration of acetylated hemicellulose from capillary hemodialyzer to blood, causing scleritis and/or iritis.

From November 1981 to early March 1982, an outbreak of scleritis and/or iritis occurred among patients treated with a Nipro brand NAC series cellulose acetate capillary dialyzer. The rate of incidence with dialyzers produced in 1982 was significantly higher than that with dialyzers produced in 1981. An extract obtained from the dialyzers caused iritis in rabbits after its infusion into an auricula vein. Glycerol, acetylated carbohydrate (AC) derivatives, urethane derivatives, and polypropyleneglycol were found in the extract. AC derivatives caused iritis in rabbits, whereas they caused hyperemia of the bulbar conjunctiva in dogs. The AC derivatives contained xylose and glucose units in a ratio of 1.6-2.3:1. The amounts of AC derivatives were significantly larger in the extracts from 1982 than from 1981 devices. Moreover, another brand, but the same type, of dialyzer, the Cordis Dow 4000, contained a slight amount of them. These facts show that AC derivatives derived from hemicellulose played a primary role in the outbreak.

Acetylation↗
PubMed1984

The clinical feature of pre-hospital phase of acute myocardial infarction--the advantages and limitations of the MCCU.

For purposes of evaluating the clinical features in the prehospital phase of acute myocardial infarction, 22 patients presenting prehospital syncope and patients presenting in-hospital re-attack were chiefly studied. Cardiac or ventricular standstill, acute mechanical failure, ventricular fibrillation, serious block, bradycardia-hypotension syndrome, cardiogenic shock, cardiac failure and cardiac rupture may be cited as the complications likely to occur in the early phase of the onset of acute myocardial infarction. Among these complications, cardiac or ventricular standstill results from overactivity of the vagus nerve, and acute mechanical failure is a result of drastically decreased cardiac output due to extensive infarction. There is no report of either complication, and both may be considered to be the fatal complications occurring almost simultaneously with the onset of acute myocardial infarction. The time intervals from the onset of symptoms to hospital admission were perspectively analyzed on 72 patients transported by the MCCU and 139 by ordinary ambulance. The interval from the onset of symptoms to medical help and that from the examination by personal physician to the call for ambulance were the greatest of all time factors, while the interval for emergency transport of the patient was short. There was no significant difference in the interval to hospital admission between the patients transported by the MCCU and those by ordinary ambulance. However, the in-transit death rate was 1/72 patients transported by the MCCU and 8/139 by ordinary ambulance: in other words, this death rate tended to be high in the latter. Twenty-two normal volunteers were studied for changes in heart rate, blood pressure and double product with the speed of transport. The transport at a low speed caused less changes in these parameters than that at a high speed.

Aged↗
PubMed1984

Study of the posterior circulation in moyamoya disease. Clinical and neuroradiological evaluation.

Eighty-two cases of cerebrovascular moyamoya disease were studied by cerebral angiography and computerized tomography. Occlusive lesions were demonstrated not only in the anterior circulation but also in the posterior circulation, and they were associated with the development of an abnormal vascular network (moyamoya vessels). Although occlusive lesions do occur in the vertebrobasilar system, the vertebrobasilar system also acts as a source of collateral channels to the anterior circulation in this disease.

Arterial Occlusive Diseases↗
PubMed1984

Cytosolic protein phosphatases of rat ascites hepatoma AH-13 as compared with those of rat liver: isolation and characterization of a novel protein phosphatase.

To investigate the alterations of phosphoseryl/phosphothreonyl-protein phosphatases in neoplastic tissues, the cytosols of rat liver and AH-13, a strain of rat ascites hepatoma, were chromatographed on DEAE-cellulose and the fractions obtained were assayed for protein phosphatase with glycogen synthase D and phosphorylase alpha as phosphoprotein substrates. While the glycogen synthase phosphatase and phosphorylase phosphatase activities of liver cytosol were largely due to phosphatases IA and II, respectively, as previously reported, these phosphatases were absent or present in only small amounts in AH-13 cytosol, whose glycogen synthase phosphatase and phosphorylase phosphatase activities were due almost wholly to a novel protein phosphatase that appeared to be absent in liver. This phosphatase, termed phosphatase H, was purified further by aminohexyl-Sepharose-4B and Sephadex G-200 chromatography without altering its glycogen synthase D/phosphorylase alpha activity ratio. Purified phosphatase H required Mg2+ or Mn2+ for activity and had a molecular weight of about 330,000. It displayed a substrate specificity broader than that of either phosphatase IA or II.

Animals↗
PubMed1984

[Digital subtraction angiography of the cerebral vessels by intraarterial injection].

Three hundred and fifty-seven digital subtraction angiography (DSA) were performed in 184 neurosurgical patients by intraarterial injection. Examinations consisted of 192 carotid angiography, 110 vertebral angiography, 23 aortography, 11 spinal angiography and 21 other angiography. In all examinations, visualization of the vessels was excellent and the complications were never experienced. High contrast sensitivity of DSA resulted in better visualization of tumor stains, phlebogram, and arteries in cerebral arteriovenous malformations with large shunt blood flow than conventional angiography. Selective catheterization into each cerebral arteries was not necessarily demanded for good opacification of the vessels because of high sensitivity. High contrast sensitivity also permitted low concentration of contrast material, small dose of contrast material, and slow injection rate. Low concentration of contrast material reduced pain and heat during injection especially in the external carotid and vertebral angiography. Using slow injection, recoiling of catheter into the aorta was reduced, so that injection from the innominate and subclavian arteries for visualization of origin of the cerebral arteries were always successful. Full study of cerebral arteries by Seldinger's method, if necessary, was easily achieved using DSA even in patient with high age or with severe atherosclerosis. Bolus injection of small dose of contrast material as well as serial imaging was helpful in evaluating hemodynamics in the lesion. Real time display of DSA reduced the time required for angiography and was very convenient for artificial embolization. Besides these advantages, DSA became comparable to conventional angiography in special resolution by use of intraarterial injection and could be a preoperative genuine examination as well as a screening method.

Adolescent↗
PubMed1984

Protective effect of FR35447 on experimental cerebral infarction.

The protective effect of 2-(5-chloro-2-phenoxyanilino)-2-imidazoline [FR35447] on cerebral infarction was examined in animal models. FR35447 in p.o. doses of 1 mg/kg or more caused a marked reduction of arachidonate-induced cerebral infarction in rats. Since FR35447 (10(-6) M) inhibited platelet aggregation induced by adrenaline plus the divalent cation ionophore A23187, as did yohimbine (10(-6) M), the protective effect of FR35447 is presumed to be due to its blocking activity on the alpha 2 adrenoceptors of platelets. However, additional mechanisms appear to participate in the protective effect of FR35447 on cerebral infarction. A ten-day treatment with FR35447 in p.o. doses of 1 to 10 mg/kg/day decreased serum lipid peroxide levels in vitamin E deficient rats, suggesting that FR35447 may have free radical scavenging activity. Moreover, FR35447 (greater than or equal to 10(-5) M) increased red cell deformability. These effects of FR35447 suggest that it may be useful in preventing or treating cerebral infarction.

Animals↗