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Biomedical subjects

S Tsuji

Publications and source records attributed to S Tsuji.

At least 973 records · Page 54Linked to original sources
PubMed1981

Silicotungstic acid for cytochemical localization of water soluble substance(s) of cholinergic motor nerve terminal.

Silicotungstic acid (STA), an electron dense substance and a powerful precipitating agent of quaternary ammonium salts such as choline and acetylcholine, was employed on the frog motor end-plate in order to prove that STA reacts with diffusible substance(s) in nerve terminals. Thus, STA treatment and osmium tetroxide (OsO4) fixation were performed in three different ways. No reaction was detectable when STA treatment followed osmification, while simultaneous treatment with STA and OsO4 darkened both presynaptic and synaptic vesicle membranes. When STA was employed directly on fresh tissues which were subsequently fixed by OsO4, small black precipitates were observed in the synaptic vesicles and none on other synaptic structures. The possible reaction of STA with acetylcholine is discussed.

Animals↗
PubMed1981

Attempted direct visualization of negatively stained amplified immune complex of synaptic acetylcholinesterase using cryoultramicrotomy sections.

An immunocytochemical method is proposed for the localization of synaptic acetylcholinesterase (AChE) on ultrathin frozen sections of the electric organ of the electric eel. The immune complex formed is amplified by a non-specific "sandwich" technique and visualized by negative staining. Definite white spots on synaptic cleft seem to correspond to basal lamina AChE molecules.

Acetylcholinesterase↗
PubMed1981

Comparison of renal ornithine transcarbamylase activities within different chicken breeds.

Comparisons were made of the renal ornithine transcarbamylase (OTC) activities within different groups of chickens including Japanese native breeds. OTC activities varied markedly within these groups. The Cochin Bantam breed and White Leghorn B line had an especially high activity, about 400 units/g of kidney, in contrast to two Japanese native breeds, Japanese Game (white variety) and Banshuu Gashiwa, and the California Gray breed, which showed a very low activity, the values being almost undetectable. In crossing experiments using the California Gray breed as a tester strain, Cochin Bantam OTC represents a simple autosomal incompletely dominant trait similar to the White Leghorn B line OTC. Kinetic studies using partially purified OTC preparations from the White Leghorn B line and Cochin Bantam breed revealed that both enzymes were identical for a variety of enzymic characteristics. In light of these results, the physiological significance of chick kidney OTC is discussed.

Animals↗
PubMed1981

The mechanism of preferential synthesis of poly[r(purine)] in the transcription of poly[d(purine)] . poly[d(pyrimidine)] by T. thermophilus RNA polymerase.

The mechanism of preferential transcription on poly[d(purine)] . poly[d(pyrimidine)] was investigated using RNA polymerase of T. thermophilus HB8. Though the machinery for initiation is lacking, the core enzyme has the latent ability to synthesize poly[r(pyrimidine)] as well as poly[r(purine)]. The holoenzyme can synthesize poly[r(purine)] in the usual manner. Poly[r(pyrimidine)] synthesis by the holoenzyme is, however, forbidden. These results suggest that the sigma factor plays a crucial role in this preferential transcription, and that this preferential transcription may be useful as a model for the sense strand recognition. Various results led us to the hypothesis that the high affinity site for the poly[d(pyrimidine)] strands on the enzyme plays a very important role.

Adenosine Triphosphate↗
PubMed1981

The quaternary structure of DNA-dependent RNA polymerase.

The crystals of RNA polymerase of T. thermophilus were examined by electron microscopic observation of the negatively stained and sectioned materials. Three types of crystals were observed: ordered aggregates (Type I), cylindrical duplei (Type II), and plane (Type III) forms. It was deduced mainly from sectioned images that Type I crystal is a precursor or a premature form of Type II crystal. The III corresponds to the flattened layer of type II. In Type II crystal the enzyme molecules are arranged in an orderly two-dimensional lattice and thus we could analyze the molecular structure by optical filtering of the negatively stained images. On the basis of these results, a quaternary structure is proposed for RNA polymerase.

Bacteria↗
PubMed1981

Studies on the Ca2+-activated neutral proteinase of rabbit skeletal muscle. I. The characterization of the 80 K and the 30 K subunits.

The structure of the calcium-activated neutral proteinase (CANP) from rabbit skeletal muscle was examined. The purified CANP was homogeneous as judged by disc gel electrophoresis, while it showed two bands (M.W.=80,000 (80 K) and 31,000 (30 K) on SDS-gel electrophoresis. After denaturation of CANP, each subunit was separated and could be renatured alone or in combination with the other subunit. The results indicate that all the machinary necessary for the proteolytic activity is present in the 80 K subunit, but for the full activity the existence of the 30 K subunit is required.

Animals↗
PubMed1981

Limited autolysis of Ca2+-activated neutral protease (CANP) changes its sensitivity to Ca2+ ions.

Ca2+-activated neutral protease (CANP) usually requires mM Ca2+ for activation. The sensitivity of CANP to Ca2+ is greatly enhanced by passing it through a casein-Sepharose column in the presence of Ca2+ ions. This conversion is ascribed to autolysis of CANP. The converted enzyme required 40 microM Ca2+ for 50% activation. Various properties of the converted enzyme were very similar to those of CANP-I, recently found in canine heart muscle. Names of "m-CANP" and "mu-CANP" are proposed for CANPs which require mM and microM order Ca2+ for inactivation, respectively.

Animals↗
PubMed1981

Increased synthesis of hexacosanoic acid (C23:0) by cultured skin fibroblasts from patients with adrenoleukodystrophy (ALD) and adrenomyeloneuropathy (AMN).

We studied the metabolism of radioactive stearic acid by cultured skin fibroblasts from patients wtih adrenoleukodystrophy (ALD) and its variant, adrenomyeloneuropathy (AMN), to clarify the mechanism of the increased content of very long chain saturated fatty acids in cholesterol esters and sphingolipids, which are known to be the characteristic biochemical changes in ALD and AMN. A substantial amount of hexacosanoic acid (C26 : 0) wa synthesized from stearic acid by ALD and AMN fibroblasts, whereas only a trace amount of hexacosanoic acid was synthesized by control fibroblasts. This indicates that the primary biochemical defect in ALD and AMN may involved the elongation system of very long chain fatty acids.

Adrenal Gland Diseases↗
PubMed1981

Studies on a Ca2+-activated neutral proteinase of rabbit skeletal muscle. II. Characterization of sulfhydryl groups and a role of Ca2+ ions in this enzyme.

The effects of Ca2+ ions on the structure and activity of Ca2+-activated neutral proteinase (CANP) were examined by means of carboxymethylation. CANP was inactivated by carboxymethylation of 1 mol of sulfhydryl group in the 80 K subunit. The sulfhydryl group was exposed to the solvent, and the buried single sulfhydryl group, which was exposed by addition of Ca2+ ions, was not essential for activity. The carboxymethylated CANP (Cm-CANP), though inactive, was indistinguishable from native CANP with respect to conformation. The structural change of Cm-CANP induced by Ca2+ at various Ca2+ concentrations and pH values corresponded well to the activity-Ca2+ and activity-pH relationships of native CANP. It is suggested that the observed conformational changes were essential for the appearance of enzyme activity. The induced structural changes occurred only around a cysteine residue and Trp and/or Tyr residues, and no significant changes in the secondary structures were observed.

Animals↗
PubMed1981

Purification and characterization of an inhibitor of calcium-activated neutral protease from rabbit skeletal muscle.

An endogenous inhibitor of calcium-activated neutral protease was purified to homogeneity from rabbit skeletal muscle using ion-exchange chromatography on DEAE-cellulose and QAE-Sephadex A-50 columns, chromatofocusing, and hydrophobic interaction chromatography on a phenyl-Sepharose CL-4B column. The purified inhibitor was shown to be a dimer of identical subunits and each subunit has a molecular weight of about 34,000. This inhibitor was remarkably thermo- and acid-stable. It was specific for calcium-activated neutral protease and had no effect on any other protease examined (trypsin, papain, alpha-chymotrypsin, bromelain, etc.). It is demonstrated that the inhibition is due to the formation of stoichiometric complex between two enzyme molecules and one inhibitor molecule.

Animals↗
PubMed1981

Autolysis of calcium-activated neutral protease of chicken skeletal muscle.

The conditions and process of autolysis of calcium-activated neutral protease (CANP) were examined. Optimal conditions for autolysis were the same as those required for expression of activity of CANP. The autolysis proceeded rapidly by a strictly limited proteolysis. During autolysis the molecular weight of CANP changed from 82 K (native CANP or mCANP) to 79 K and then 60 K. The 79 K and 60 K molecular species were both active at microM order of Ca2+ (muCANP), whereas the native CANP is active at mM order of Ca2+ (mCANP). Various proteases examined did not produce muCANP from mcanp under the conditions tested. Furthermore, muCANP did not yield muCANP from mCANP at lower Ca2+ concentrations where only muCANP was active. Therefore, muCANP is produced from mCANP only by the specific autolysis of mCANP.

Animals↗
PubMed1981

Abnormality of long-chain fatty acids in erythrocyte membrane sphingomyelin from patients with adrenoleukodystrophy.

We have devised an analytical method for the determination of fatty acid composition of erythrocyte membrane sphingomyelin by chemical ionization mass spectrometry combined with capillary column gas-liquid chromatography. Fatty acid composition of erythrocyte membrane sphingomyelin from 8 patients with adrenoleukodystrophy (ALD) and 16 healthy controls were examined by this method. The ratio of hexacosanoic acid (C26:0) to docosanoic acid (C22:0) in erythrocyte membrane sphingomyelin from ALD patients was 2.6-fold higher than that of the controls. This result suggests that biochemical diagnosis of ALD is possible by the analysis of fatty acid composition of erythrocyte membrane sphingomyelin. Furthermore, it demonstrates that biochemical abnormality in ALD is the generalized abnormal metabolism of very long-chain saturated fatty acids.

Chemical Phenomena↗
PubMed1981

Cortical deafness in multiple sclerosis.

Cortical deafness in a patient with multiple sclerosis is reported. Complete recovery from total deafness was seen following stages of auditory agnosia and pure word deafness. The otological and neurophysiological studies suggested lesions in subcortical white matter. This report stresses the rarity of the condition, its subcortical origin and good prognosis.

Adult↗
PubMed1981

Treatment of severe hypertension and hypertensive emergency with nifedipine, a calcium antagonistic agent.

Nifedipine, the Ca++ antagonistic coronary vasodilator, was administered by oral, sublingual and enema routes. 1) In 6 severe hypertensive patients (systolic pressure greater than or equal to 200 mmHg, diastolic greater than or equal to 120 mmHg), nifedipine, administered orally, induced prompt and reliable fall of arterial pressure (systolic pressure: -28% of control level, diastolic: -27%). 2) In 10 patients with hypertensive emergencies, including malignant hypertension, intracranial bleeding, hypertensive encephalopathy and acute hypertensive heart failure, sublingual and enema administration of nifedipine were performed with excellent hypotensive efficacy. 3) Pressure began to fall within 5--15 min, 30 min and 30--60 min after sublingual (or dissolved), enema and oral (capsule), respectively, and reached its lowest levels in the next 10--20 min. The fall of pressure lasts for 2--4 hours. 4) In the combination of nifedipine with alpha-methyldopa, antihypertensive response in short-term was increased about +11% over nifedipine alone and lasted for 8 hours. In combination with beta-blocker (propranolol), hypotensive efficacy increased +39% over nifedipine alone, but the effective duration of this combination was the same as nifedipine alone. 5) Side effects, including dryness of the mouth and burning sensation in face and legs, were observed in few patients.

Administration, Oral↗
PubMed1981

[A case of neuronal ceroid-lipofuscinosis (Jansky-Bielshowsky type): morphological, biochemical and electrophysiological studies (author's transl)].

We reported a case of late infantile neuronal ceroid-lipofuscinosis. The patient was an 8-year-old boy presenting with marked psychomotor deterioration, progressive visual failure due to retinal degeneration and optic atrophy, startle reaction to auditory stimuli, frequent myoclonus and generalized convulsions. The routine laboratory examinations were all normal. EEG was markedly abnormal because of poorly organized background activity and frequent paroxysmal spike-and-wave complexes. CT scan showed evidence of severe atrophy of the cerebrum, cerebellum and brainstem. Electron microscopic examination of the biopsied rectum revealed fingerprint profiles in the neurons and pericytes beneath the muscularis mucosa. Cultured skin fibroblasts also contained electron dense inclusions, some of which showed fingerprint profiles. Urinary glycopeptides were normal. Lyscsomal enzyme activities in leukocytes and cultured fibroblasts were normal. Neurophysiological studies revealed giant cortical potentials evoked by the auditory as well as somatosensory stimulation. Simultaneous recording of the somatosensory evoked EEG and EMG potentials disclosed that the myoclonus in this patient was stimulus-sensitive and compatible with the cortical reflex myoclonus. With regard to hypothetical pathogenesis of this disease, we studied lipoperoxide in the blood before and after anti-oxidant therapy. We also measured vitamin A and carotene, since these substrates are related to retinoic acid. Although vitamin A and carotene were normal, lipoperoxide was slightly elevated. However, it was not influenced by the treatment with anti-oxidant. Significance of elevated lipoperoxide to the pathogenesis of this diseases has not solved.

Ceroid↗