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Biomedical subjects

S Endo

Publications and source records attributed to S Endo.

At least 559 records · Page 31Linked to original sources
PubMed1989

[MRI of acute cerebral infarction].

Sequential changes of magnetic resonance imaging (MRI) in sixteen patients with acute cerebral infarction are studied in comparison with the findings of computed tomography (CT). The sixteen patients were examined within 36 hours from the onset of symptoms on resistive type MRI (0.15T) using T1 weighted image (IR2000/500) and T2 weighted image (SE2000/80), and on CT. In general, large infarcted lesions of the cortex-subcortex seemed to be visualized earlier than small lesions of the basal ganglia and brainstem. In 8 patients, the infarcted lesions were detected on MRI earlier than on CT. For example, early detecting time within 12 hours were 2, 6, 7, and 10 hours after onset. In two patients of this group, lesions were detected on T2-weighted image earlier than on T1-weighted image. In two cases, small lesions of the brainstem were detected only on MRI. The size of abnormal findings gradually developed and reached a maximum on days 5 to 7 sequentially. The difference between infarction and perifocal edema was not clear even on MRI. The changes gradually subsided and assumed a stable size after about 2 months. Contrast enhancement effect was observed in four patients. In two of these cases, the signal intensity of T2-weighted imaging was decreased just at the region which was enhanced with contrast medium. MRI is useful for early diagnosis of ischemic cerebral infarction, and may elucidate some aspects of the pathophysiology of ischemic stroke.

Acute Disease↗
PubMed1989

[Operative correction of kinking and coiling at the origin of vertebral artery and stellate ganglionectomy in patients with severe vertigo and dizziness].

Bilateral vertebral angiograms were taken in 125 cases with severe vertigo and dizziness during the period between April 1983 and March 1986. Various kinds of morphological abnormalities were found. Most impressive findings were kinking and coiling at the first portion of the vertebral artery, which was corrected by operation in 54 cases out of 100 cases. This method is accompanied with stellate ganglionectomy and completed by rolling the subclavian artery forwards and downwards with ligation. The follow-up results were evaluated one to four years after operation. Symptoms were cured in 50 cases out of 54. The postoperative course was satisfactory. It was emphasized in this paper that our operation was very useful for patients with severe and recurrent vertigo.

Adult↗
PubMed1988

Structural analyses of asparagine-linked oligosaccharides of porcine pancreatic kallikrein.

The structures of asparagine-linked oligosaccharides of porcine pancreatic beta-kallikrein are reported. Asparagine-linked neutral oligosaccharides were released by N-oligosaccharide glycopeptidase digestion, and the reducing ends of the oligosaccharides were derivatized with a fluorescent reagent, 2-aminopyridine. The mixture of pyridylamino oligosaccharides was separated by reverse-phase and amide-adsorption high-performance liquid chromatography. The pyridylamino oligosaccharides were separated into more than 50 kinds of oligosaccharides. The structures of 5 kinds of triantennary and 12 kinds of tetraantennary oligosaccharides were determined by the use of high-resolution proton nuclear magnetic resonance spectroscopy and methylation analysis. Furthermore, the structures of five kinds of oligomannose-type oligosaccharides were elucidated by a combination of exoglycosidase digestion and high-performance liquid chromatography. 1H NMR data for 14 out of the 17 kinds of N-acetyllactosamine-type oligosaccharides reported here have not previously been described in the literature. (1) It has been shown that fucose containing tri- and tetraantennary oligosaccharides is predominant in porcine pancreatic beta-kallikrein B. (2) It has also been shown that the heterogeneity of the structure in these types of oligosaccharides is derived from the variety of the positions of galactose residues linked to outer N-acetylglucosamine residues. (3) The distribution of oligosaccharides into two glycosylation sites, asparagine-95 and asparagine-239, of beta-kallikrein B was determined. It has been found that oligomannose-type oligosaccharides are exclusively present at asparagine-239, although N-acetyllactosamine-type oligosaccharides occur at both glycosylation sites.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Analyses of N-linked oligosaccharides using a two-dimensional mapping technique.

We propose a two-dimensional sugar map method for the simple, reproducible, and sensitive analysis of the structures of N-linked oligosaccharides. The structure of an unknown oligosaccharide can be characterized from its position on the map. The data base for the sugar map is prepared by the use of 113 kinds of standard oligosaccharides, 58 of whose structures have been confirmed by 1H NMR spectroscopy. The present method involves six steps, (i) preparation of oligosaccharides from glycopeptides by N-oligosaccharide glycopeptidase (almond) digestion, (ii) derivatization of the reducing ends of oligosaccharides with a fluorescent reagent, 2-amino-pyridine, by using sodium cyanoborohydride, (iii) separation of oligosaccharide derivatives by high-performance liquid chromatography with an ODS-silica column, (iv) analysis of the size of each separated oligosaccharide on an amide-silica column, (v) plotting of the elution position of a sample on the two-dimensional sugar map obtained for the standard oligosaccharides, and (vi) structural analysis of the oligosaccharides by a combination of sequential exoglycosidase digestion and the steps (iii-v). The present method was applied to the identification of the structures of oligosaccharides in hen ovalbumin. It was found that two unusual oligosaccharides that have not yet been reported exist in ovalbumin.

Animals↗
PubMed1988

51-kd protein, a component of microtubule-organizing granules in the mitotic apparatus involved in aster formation in vitro.

Mitotic apparatuses (MAs) isolated from sea urchin metaphase eggs were chilled on ice to depolymerize microtubules, homogenized, and incubated with tubulin. This caused formation of many small asters with microtubules focusing on granules which were probably fragments of the centrosome. The aster-forming protein components of the granules in the homogenized MAs were solubilized in 0.5 M KCl containing 50% glycerol. After dialysis against low-ionic-strength buffer solution, proteins congregated to form granular assembly capable of initiating aster formation. Phosphocellulose column chromatography enabled the separation of the aster-forming protein fraction which contained a 51,000 molecular weight protein (51-kd protein) as a major component. The protein fraction possessing the aster-forming activity was also prepared from methaphase whole egg homogenate, and the elution profile of the 51-kd protein on phosphocellulose column also coincided with that of the aster-forming activity. The granular assembly reconstituted from the phosphocellulose fraction formed asters whose microtubules show the same growth rate and length distribution as those of asters reconstructed from the granules in the homogenized MAs. Anti-51-kd protein antibody that was raised in rabbit and affinity-purified stained the center of asters which were reconstructed either from the granules in the homogenized MAs or from the granular assembly reconstituted from the phosphocellulose fraction. These results suggest that the 51-kd protein is a component in the aster-forming activity of the centrosomal component in vitro.

Animals↗
PubMed1988

Effects of cholesterol feeding to maternal rats on metabolism of cholesterol and bile acids in the dams and their offspring.

The influence of feeding cholesterol to rats during pregnancy and postpartum (from the 11th day of gestation to the third day after delivery) on the serum and hepatic cholesterol levels and on the bile acid composition in the pool and in the liver in relationship to the dams and their pups was examined. The hepatic content of cholesterol in both dam and offspring increased during cholesterol feeding without any changes in serum cholesterol level. In the dams, mainly the esterified cholesterol was increased; in the pups, mainly the free cholesterol was increased. Cholesterol feeding led to a pronounced increase in the pool of beta-muricholic acid and a relative decrease in the lithocholic acid concentration in pregnant rats. In fetal rats, the chenodeoxycholic acid pool was increased by cholesterol intake. The lithocholic acid pool was larger in the postpartum rats fed cholesterol than in the controls, while the concentration of alpha- and beta-muricholic acids was decreased. The neonates of cholesterol-fed dams had a larger pool of chenodeoxycholic acid but a smaller pool of beta-muricholic acid. These results suggest that the metabolism of cholesterol and of bile acids in dams and their offspring respond differently to cholesterol intake.

Animals↗
PubMed1988

Relation of supersensitivity to cerebral vasospasm induced by oxyhaemoglobin.

There have been reports that superior cervical ganglionectomy (SCG) is effective as a treatment for cerebral vasospasm following subarachnoid haemorrhage (SAH). On the other hand, denervation supersensitivity is supposed to play an important role in vasospasm. The two accounts contradict each other. To investigate this problem, various examinations were performed using the exposed basilar arteries of cats. We have accepted that oxyhaemoglobin (Oxy-Hb) is an important spasmogenic substance. Therefore, the change in vascular reactivity to Oxy-Hb was investigated after various kinds of denervations. It was confirmed that Oxy-Hb has no adrenergic receptor agonist properties because the Oxy-Hb inducing vasospasm was not suppressed by Prazosin or phenoxybenzamine. As a result of this, it is not likely that augmentation of Oxy-Hb inducing vasospasm is caused by deviation supersensitivity. Thus, the non-deviation supersensitivity became a topic of investigation. The basilar arteries were denervated by chemical treatment (reserpine, 6-hydroxydopamine) or bilateral SCG to examine the change in the reactivity to noradrenaline or Oxy-Hb. An increase in reactivity to noradrenaline was observed with the denervations. In contrast, no change in reactivity to Oxy-Hb was found. In conclusion, it was observed that deviation and non-deviation supersensitivity do not participate in vasospasm, in so far as vasospasm is caused by Oxy-Hb.

Animals↗
PubMed1988

Probing stability and dynamics of proteins by protease digestion. II: Identification of the initial chymotryptic cleavage sites of homologous cytochromes c.

Three homologous cytochromes c from horse, rabbit and tuna were subjected to chymotryptic digestion and their initial cleavage sites were identified. The sites in oxidized cytochromes c are the COOH-terminal sides of Tyr-48, Phe-46 and Tyr-46 for horse, rabbit and tuna cytochromes c, respectively. The results show that the chymotrypsin attacks a single site in each protein; the sites are located at the almost identical position on the polypeptide chain. Through the time-course studies of digestion, it was found that the three cytochromes c have different chymotrypsin-susceptibility at the initial cleavage site in the order of horse less than rabbit less than tuna. Studies on chymotryptic digestion of tuna cytochrome c in the reduced form revealed that the haem-reduction does not alter the initial cleavage site but increases the resistance to the proteolysis at the site. The uniqueness of the initial cleavage site in each cytochrome c species suggests that the protease susceptibility reflects some overall properties of the protein. At the same time, it was clarified that the initial cleavage site is also affected by a neighboring region by the fact that another potential cleavage site is located near the site in question. In order to elucidate the initial cleavage site, several physical properties of tuna cytochrome c molecule deduced from the X-ray 3D structure, accessible surface area, temperature factor, effective hydrophobicity and electrostatic potential, were compared with the experimental results and it was concluded that these properties given by a residue have no direct relationship with the chymotrypsin susceptibility.

Amino Acid Sequence↗
PubMed1988

Purification and characterization of a substance P-degrading endopeptidase from rat brain.

A novel substance P-degrading endopeptidase has been solubilized with Brij 35 from a membrane fraction of rat brain and purified by a procedure involving DEAE-cellulose chromatography, hydroxyapatite chromatography, Sephadex G-100 gel filtration, and Mono-Q HPLC. The activity of the degrading enzyme was monitored by measuring the disappearance of substance P by means of a bioassay and HPLC. SDS-polyacrylamide gel electrophoresis under reducing conditions of the enzyme gave a single band corresponding to a molecular weight of 58,000. The molecular weight of the enzyme was estimated to be 55,000 by gel filtration and the optimum pH for its activity was 7.5.. The purified enzyme cleaved substance P at three bonds, Pro4-Gln5, Gln5-Gln6, and Gln6-Phe7, in the ratio of 2:2:3. EDTA, o-phenanthroline, and p-chloromercuribenzenesulfonic acid strongly inhibited the enzyme, while diisopropyl fluorophosphate, E-64, Z-Gly-ProCH2Cl, phosphoramidon, and captopril had little or no inhibitory effect on it. The cleavage of substance P by the rat brain synaptic membrane was also analyzed under the conditions with or without these inhibitors. The inhibitor-susceptibility of the cleavage sites suggests that the present enzyme, together with endopeptidase-24.11, is involved in the degradation of substance P in the synaptic region.

Amino Acid Sequence↗
PubMed1988

A twin study of febrile convulsions in the general population.

Seven monozygotic (MZ) and six dizygotic (DZ) twin pairs with febrile convulsions (FC) in the general population were studied. The pairwise concordance rate for FC in MZ 85.7% (6/7) was higher than that in DZ 16.7% (1/6). In a discordant MZ pair, the unaffected co-twin was attacked by epileptic seizures later. Between the concordant DZ twins, the clinical symptoms and EEGs differed in quality. According to the ratio of concordance rate in MZ to that in DZ 5.1, a multifactorial mode of inheritance for FC was suspected.

Child↗
PubMed1988

Spike EEG abnormalities in patients without epileptic seizures: a clinical and long-term follow-up study.

A study was conducted on a total of 850 patients who had not previously manifested any epileptic seizures but exhibited at least one spike EEG abnormality. They accounted for 7.2% of the total number of patients without epileptic seizures (850/11,773). Among the 850 patients, 564 were followed up for 1-24 years. Nine boys and one girl, i.e. 1.8% of the 564 patients, had manifested epileptic seizures during the observation period. They expressed the following six characteristics: males, first EEG examination at 0-4 years of age, onset of initial chief complaints at 0-6 years of age, mental retardation, spike and wave EEG abnormalities and past history of perinatal birth injuries. These factors are considered to be efficient in detecting patients liable to manifest epileptic seizures later.

Adolescent↗
PubMed1988

Experimental model of symptomatic vasospasm in rabbits.

The common carotid arteries were ligated bilaterally 2 weeks before induction of subarachnoid hemorrhage in rabbits. The rabbits were observed closely for clinical symptoms, and angiographic and pathologic investigations were performed. Thirteen experimental rabbits showed a progressing neurologic deficit that was worst on the fourth or fifth day after the subarachnoid hemorrhage. This symptomatic change did not occur in five rabbits without previous carotid ligation. Presumably, the rabbits with carotid ligation became symptomatic because they no longer had a collateral blood flow to compensate for the reduced blood flow in the basilar artery after subarachnoid hemorrhage. Our model of symptomatic vasospasm after subarachnoid hemorrhage may be beneficial for future studies.

Animals↗
PubMed1988

[Pharmacological studies of eicosapentaenoic acid ethylester (EPA-E) on high cholesterol diet-fed rabbits].

The effects of eicosapentaenoic acid ethylester (EPA-E) at daily doses of 3 and 30 mg/kg (p.o.) on vascular lesions and changes in blood components were investigated in rabbits fed with a 1% cholesterol diet for 12 weeks and partly compared with those given 30 mg/kg/day (p.o.) of ticlopidine. EPA-E at 30 mg/kg significantly improved the reduction in distensibility of isolated thoracic aorta caused by cholesterol diet feeding. Ticlopidine at 30 mg/kg also showed significant but milder improvement. EPA-E at 30 mg/kg, unlike ticlopidine, tended to lower cholesterol content in the thoracic wall and elastin fraction. Although EPA-E did not act on plasma total cholesterol, HDL-cholesterol and triglyceride contents, it tended to mildly reduce platelet aggregability in response to sodium arachidonate and the increased production of TXA2-like activity by platelets. In addition, daily doses of 30 mg/kg EPA-E caused a significant increase in plasma and platelet EPA-E contents without any change in docosahexaenoic acid and arachidonic acid contents. From these results, daily administration of EPA-E to cholesterol diet-fed rabbits caused a remarkable improvement of the reduction in distensibility of isolated thoracic aorta. The mechanism of this improvement by EPA-E appears to depend on the protection of elastic fibers from lipid deposition on the vascular wall.

Animals↗
PubMed1988

[The effects of eicosapentaenoic acid ethyl ester (EPA-E) on arterial thrombosis in rabbits and vascular lesions in rats].

The effects of highly purified ethyl ester of eicosapentaenoic acid (EPA-E) on ellagic acid-induced thrombus formation in the stenosed femoral artery in rabbits and on the progression of laurate-induced vascular lesions in rats were examined. (1) EPA-E in single administration significantly prevented the thrombus formation induced by ellagic acid in the stenosed femoral artery of rabbits. (2) EPA-E restored the hypercoagulation activity at 5 min and 3 hr after the ellagic acid injection. Platelet aggregability induced by arachidonic acid decreased at 5 min and 3 hr after the ellagic acid injection; EPA-E had little effect on this change. EPA-E showed almost no effect on fibrinolytic activity, blood viscosity and filterability of washed red blood cells after the ellagic acid injection. (3) Moreover, EPA-E in daily administrations showed a significant preventative effect against the laurate-induced vascular lesions in rats. The efficacy of EPA-E on arterial thrombosis and vascular lesions observed in this study suggests that EPA-E is a candidate for the treatment of peripheral circulatory disturbance.

Animals↗
PubMed1988

[Experimental cerebral vasospasm induced by oxyhemoglobin and the sympathetic nervous system (Part 1): Effect of alpha-adrenergic receptor blockers].

This study was performed as part of a series of investigations into the relation between cerebral vasospasm following subarachnoid hemorrhage and the sympathetic nervous system. We studied the effect of phenoxybenzamine chloride (POB) and prazosin hydrochloride (Prazosin) on the cerebral vasoconstriction in the basilar arteries of cats induced by application of oxyhemoglobin (Oxy-Hb), noradrenaline (Nor) and prostaglandin F2 alpha (PGF2 alpha). Adult cats were anesthetized with intramuscular pentobarbital and maintained on a respirator through a tracheostomy. By the transclival approach, a bone window was formed in the clivus, and the dura was opened, exposing the basilar artery. A cannule was inserted into the subarachnoid space, and through it, Oxy-Hb, Nor and PGF2 alpha were injected. The sequential changes in caliber of the basilar artery were measured using photography. First, we determined the doses of POB and Prazosin necessary for decreasing the vasoconstriction induced by Nor, and 20 mg/kg of POB and 10 mg/kg of Prazosin were found to decrease the vasoconstriction induced by 10(-3) M Nor, statistically. Second, we investigated the effect of 20 mg/kg of POB and 0.5 mg/kg and 10 mg/kg of Prazosin on the cerebral vasoconstriction induced by Oxy-Hb or PGF2 alpha. POB (20 mg/kg) was infused for 2 hours before the application of Oxy-Hb or PGF2 alpha. Prazosin was given intravenously. In the first group, 0.02% Prazosin (0.5 mg/kg) was administered intravenously for 1.5 hours before the application of Oxy-Hb or PGF2 alpha. In the second group, 1.5 hours elapsed between the beginning of Prazosin (10mg/kg) infusion and the application of Oxy-Hb or PGF2 alpha.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic alpha-Antagonists↗
PubMed1988

[Experimental cerebral vasospasm induced by oxyhemoglobin and the sympathetic nervous system (Part 2): An investigation into denervation supersensitivity].

UNLABELLED: The pathological mechanism of cerebral vasospasm following subarachnoid hemorrhage has not been well clarified until now. There have been reports that denervation supersensitivity in cerebral vessels occurring after subarachnoid hemorrhage may possible play a role in the appearance of cerebral vasospasm. On the other hand, we have accepted that oxyhemoglobin (Oxy-Hb) is an important spasmogenic substance. In the present study, we investigated the effect of chemical denervation (reserpine or 6-hydroxydopamine: 6-OHDA) and surgical denervation (bilateral superior cervical ganglionectomy: SCG) on the constrictive sensitivity of cat basilar arteries to noradrenaline (Nor) and oxyhemoglobin (Oxy-Hb) in situ. METHOD: Adult cats were anesthetized with intramuscular pentobarbital and maintained on a respirator through a tracheostomy. By the transclival approach, the basilar artery was exposed. A cannula was then inserted into the subarachnoid space, and through it, Oxy-Hb and Nor were injected. The sequential changes in caliber of the basilar artery were measured using photography. SCG was done 7 days before the application of Nor or Oxy-Hb and 14 days before application of Oxy-Hb. Pretreatment with reserpine was done as follows: 1 mg/kg of reserpine was injected subcutaneously once each day for 2 days. On the following day, the sensitivity of the basilar arteries to Nor or Oxy-Hb was assessed. Pretreatment with 6-OHDA was done as follows: 5 mg of 6-OHDA was dissolved in 1.0 ml of artificial CSF, and then injected into the cisterna magna. Seven days later, Nor or Oxy-Hb was applied. RESULTS: Pretreatment with reserpine tended to increase the vasoconstriction induced by 10(-7)-10(-4) M of Nor and the constriction induced by 10(-3) M of Nor was increased statistically (P less than 0.05). Cisterna magna injection of 6-OHDA tended to increase the vasoconstriction induced by Nor. SGG tended to increase the vasoconstriction induced by 10(-7)-10(-4) M of Nor and at a dose of 10(-3) M of Nor, the constriction of the basilar arteries was increased statistically (P less than 0.05). However, pretreatment with reserpine, 6-OHDA and SCG did not increase the vasoconstriction induced by Oxy-Hb. These results lead us to suggest that denervation supersensitivity does not participate in the vasoconstriction induced by Oxy-Hb.

Animals↗
PubMed1988

[Studies on the absorption and excretion of rokitamycin in infant beagle dogs. Comparison with adult beagle dogs].

Absorption and excretion of rokitamycin (RKM) were studied after oral administration of 50 mg/kg to fasted infant and adult Beagle dogs. In infant Beagle dogs, the mean plasma level of RKM reached its peak of 6.53 micrograms/ml in 15 minutes after administration. The area under the curve (AUC) value was 11.04 micrograms.hr/ml. In adult Beagle dogs, the mean plasma level of RKM reached its peak of 8.62 micrograms/ml in 30 minutes after administration. The AUC value was 18.25 micrograms.hr/ml. Ratios of Cmax and AUC value in infant Beagle dogs to those in adults were about 75% and 60%, respectively. In infant Beagle dogs, urinary excretion of RKM was 2.55% of the dose within 24 hours. In adult Beagle dogs, urinary excretion of RKM was 3.03% of the dose within the same period. The excretion ratio of RKM in infant Beagle dogs was about 85% of the adults' value.

Absorption↗