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Biomedical subjects

S Nishimura

Publications and source records attributed to S Nishimura.

At least 991 records · Page 55Linked to original sources
PubMed1976

The EEG in normal pressure hydrocephalus.

Fourteen patients with NPH were studied with special reference to associated EEG changes, one case being reported in detail. In 13 cases the EEG was abnormal, the abnormality most frequently observed being a of the rhythmic slow wave type, consisting of bursts of monorhythmic theta or delta waves seen in both hemispheres. This type of abnormality was present in 7 cases. In 4 of the 5 cases with serial EEG's the abnormality became more accentuated with the advance of the illness. In 4 of 5 cases in whom postoperative EEGs were obtained there was significant improvement of the EEG after the shunting procedure. There were stron correlations between the EEG abnormality described, demonstrable ventricular reflux on cisternography, and the effectiveness of the shunt operation. It was considered that serial EEGs are a useful diagnostic procedure in following up patients at risk of developing NPH.

Adult↗
PubMed1976

Specific replacement of Q base in the anticodon of tRNA by guanine catalyzed by a cell-free extract of rabbit reticulocytes.

Guanylation of tRNA by a lysate of rabbit reticulocytes was reported previously by Farkas and Singh. This reaction was investigated further using 18 purified E. coli tRNAs as acceptors. Results showed that only tRNATyr, tRNAHis, tRNAAsn and tRNAAsp which contain the modified nucleoside Q in the anticodon acted as acceptors. Analysis of the nucleotide sequences in the guanylated tRNA showed that guanine specifically replaced Q base in these tRNAs.

Animals↗
PubMed1976

The nucleotide sequence of asparagine tRNA from Escherichia coli.

The nucleotide seuquence of Escherichia coli asparagine tRNA was determined to be pU-C-C-U-C-U-G-s4U-A-G-U-U-C-A-G-D-C-G-G-D-A-G-A-A-C-G-G-C-G-G-A-C-U-Q-U-U-t6A-A-phi-C-C-G-U-A-U-m G-U-C-A-C-U-G-G-T-phi-C-G-A-G-U-C-C-A-G-U-C-A-G-A-G-G-A-G-C-C-AOH. Its D-stem and D-loop have almost the same sequence as Escherichia coli aspartate tRNA.

Asparagine↗
PubMed1976

Biosynthesis of the modified nucleoside Q in transfer RNA.

During biosynthesis of the modified nucleoside Q, 7-(4,5-DIHYDROXYL-1-1-CYCLOPENTEN-3-YL-AMINOMETHYL)-7-DEAZAGUANOSINE, IN TRNA, the carbon atom at position 8 in precursor molecule guanine was expelled together with the nitrogen atom N-7 in a fashion similar to that in the biosynthesis of the nucleoside antibiotic toyocamycin.

Chromatography, Thin Layer↗
PubMed1976

CD spectra of 5-methyl-2-thiouridine in tRNA-Met-f from an extreme thermophile.

5-Methyl-2-thiouridine (S) in tRNA-Met-f from an extreme thermophile is located in the TpsiC region, replacing T, and has a positive CD band centered at 310 nm. Upon heating, the profiles of the change in this band were similar to the UV melting profiles of the change monitored at 260 nm. This strongly suggests a close relation between heat denaturation of the tRNA and the conformation of the S base. Oligonucleotides containing S showed negative CD bands at 320-330 nm, like the monomer S itself, but when the 3'-2/5 fragment containing S formed a complex with the complementary 5'-3/5 fragment, a positive CD band appeared at 310 nm. These results suggest that combination of the TpsiC loop containing S with the hU loop is necessary for the positive band of S at 310 nm. S may serve to strengthen the association of the TpsiC loop with the hU loop in tRNA of the thermophile.

Bacteria↗
PubMed1976

[A midline vertebral artery aneurysm operated via transoral transclival approach (author's transl)].

A detail of an unsuccessful trial of transoral transclival operation for an aneurysm arising from the left vertebral artery was reported. The patient was 66 years old male who had bronchial asthma and difficulty in phonation and swallowing. The angiograms showed that the aneurysm, 1.5X1.5X2.0 cm in size, was situated in the midline at the level of caudal one-third of the clivus. A transoral transclival operation was performed following preoperative tracheostomy and gastrostomy to improve his pulmonary and nutritional condition. A midline incision on the palate was followed by the removal of the posterior half of palatal bone. The upper part of incision on the retropharyngeal mucosa was placed approximately 1 cm off the midline to facilitate closure afterwords. A caudal 1/3 of the clivus, anterior arch of the atlas and a part of the odontoid process were removed. The aneurysm, fusiform in shape, was then collapsed by needle puncture after the left vertebral artery was trapped between the posterior inferior cerebellar artery and the vertebro-basilar junction. Closure of the dura with a fascial patch was incomplete due to an extensive incision and coagulation of the dura. Closure of the retropharyngeal mucosa around the orifice of the Eustachian tube was also incomplete in spite of the paramedian incision described above. Postoperative course was complicated by an frequent occurrence of the attack of bronchial asthma causing loss of gastic juice from the gastrostomy and resultant hypoproteinemia, although the recovery of lower cranial nerve palsy was good. There was no signs of infection until the 21st postoperative day when meningitis developed. The patient died in the 28th postoperative day. The importance of complete closure of the dura and retropharyngeal mucosa to prevent meningial infection was discussed. Since the mucosa around the orifice of Eustachian tube was extremely friable and the closure was almost impossible, the risk of meningial infection was considered to be high, especially when the intradural procedure was necessary through transoral high clivotomy.

Aged↗
PubMed1976

[Aneurysm of the great vein of Galen--report of a case (author's transl)].

A case of aneurysm of the great vein of Galen was reported in which craniotomy and clipping of a feeding artery arising from the left posterior cerebral artery was successfully performed. This 5-month-old girl developed progressive hydrocephalus from 2 months after birth. At 5 months the head circumference was 50 cm with tense enlarged fontanelle. Both eye balls were deviated downward. The deep tendon reflexes were hyperactive with bilateral ankle clonus and positive Babinski's sign. Mild cardiomegaly and hepatomegaly were also noted. Cerebral angiograms showed a large aneurysm of the great vein of Galen fed by a single enlarged arterial branch from the left posterior cerebral artery. After the evaluation of systemic circulatory status and under strict control of fluid transfusion craniotomy was performed. The feeding artery was clipped at its entrance to the aneurysm via left parieto-occipital interhemispheric approach. A rise in the mean arterial blood pressure of 20 mmHg was observed immediately following clipping. The postoperative course was satisfactory except for a left subdural fluid collection which required subduro-peritoneal shunt. The aneurysm was completely disappeared on the postoperative angiograms and the child is regaining the normal development. This is the first case of aneurysm of the great vein of Galen successfully operated in Japan. Clinical symptoms and signs, radiological features and operative treatment of the disease were reviewed from a total of 46 cases reported in the world literature.

Brain↗
PubMed1975

Structure of the modified nucleoside Q isolated from Escherichia coli transfer ribonucleic acid. 7-(4,5-cis-Dihydroxy-1-cyclopenten-3-ylaminomethyl)-7-deazaguanosine.

The structure of the unknown modified nucleoside Q, which is present in the first position of the anticodons of Escherichia coli tRNA Tyr, tRNA His, tRNA Asn, tRNA Asp, is proposed to be 7-(4,5-cis-dihydroxy-1-cyclopenten-3-ylaminomethyl)-7-deazaguanosine (1). The structure of Q was deduced by means of its uv absorption, mass spectrometry, proton magnetic resonance spectroscopy, and studies of its chemical reactivity. The structure of Q is unique since it is a derivative of 7-deazaguanosine having cyclopentenediol in the side chain at the C-7 position. This is the first example of purine skeleton modification in a nucleoside from tRNA.

Anticodon↗