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Biomedical subjects

S Iijima

Publications and source records attributed to S Iijima.

At least 181 records · Page 10Linked to original sources
PubMed1986

Nucleotide sequence of the malate dehydrogenase gene of Thermus flavus and its mutation directing an increase in enzyme activity.

The nucleotide sequence of the malate dehydrogenase (mdh) gene from a thermophilic bacterium, Thermus flavus, was determined. The amino acid sequence of the Thermus malate dehydrogenase resembled that of the porcine heart cytoplasmic enzyme to a certain extent, and Asp-159 and His-187 were identified as possible essential residues for the catalytic function. The mutated mdh gene was also cloned from a spontaneous mutant of T. flavus containing a higher activity of the enzyme. Its mutation point was determined to be a single nucleotide exchange from C to T which caused Thr-190 to be substituted by isoleucine. The mutated enzyme showed resistance to substrate inhibition, an increase in both kcat and Km, and a shift toward a more acid optimum pH for the enzyme reaction.

Amino Acid Sequence↗
PubMed1986

Tripolyphosphatase associated with S-adenosylmethionine synthetase isozymes from rat liver.

S-Adenosylmethionine (AdoMet) synthetase alpha and beta were purified to homogeneity, as judged by SDS-polyacrylamide gel electrophoresis from rat liver. When the purified enzymes were applied onto Sephacryl S-200, each synthetase was eluted together with a tripolyphosphatase. The activities of these isozymes in synthesizing AdoMet and in hydrolyzing tripolyphosphate decreased in parallel with increasing amounts of rabbit anti-(beta-form) IgG. The activity of the beta-form isozyme was markedly stimulated by the addition of tripolyphosphate, whereas that of the alpha-form isozyme was inhibited. The tripolyphosphatase activity of both the alpha- and the beta-form was markedly stimulated by the addition of AdoMet. The tripolyphosphatases of each isozyme showed some other similar properties.

Acid Anhydride Hydrolases↗
PubMed1986

Characterization of an essential histidine residue in thermophilic malate dehydrogenase.

Heat-stable malate dehydrogenase isolated from Thermus flavus AT62 was completely inactivated by treatment with diethylpyrocarbonate. The inactivation was accompanied by the loss of 1.2 histidine residues per subunit of the enzyme. The enzyme was protected from inactivation by NADH. The enzyme was also inactivated by dye-sensitized photooxidation. Methionine residues, in addition to histidine residues, were destroyed in the inactivated enzyme. Kinetic analyses of the inactivation indicated that the pK value of the residue involved in the inactivation was 8.20 at 25.0 degrees C and 7.52 at 60.0 degrees C. From the pK values and the heat of ionization calculated from the van't Hoff plot of pKs, a histidine residue was identified to be primarily involved in the inactivation. The effect of temperature on the pK value of the essential group in this enzyme from a thermophilic organism is discussed.

Diethyl Pyrocarbonate↗
PubMed1986

Therapeutic effects of mazindol on narcolepsy.

Mazindol, a new anorexiant, was administered at a daily dose of 0.5-4 mg to 10 narcoleptic subjects aged 21-63 years. All the patients suffered from sleep attacks and one or more of the REM-related symptoms. Eight patients received only mazindol, and two patients received mazindol simultaneously with clomipramine or flurazepam. Sleep attacks were reduced in nine patients, and cataplexy was also markedly reduced in four patients. Mild adverse reactions were reported in six patients: two patients complained of headache, four of nocturnal sleep disturbance, and two of reduced appetite. Most side effects disappeared spontaneously or after dose reduction, and none of the patients had to stop medication. The results suggest that mazindol is effective not only for sleep attacks but also for cataplexy. It is recommended as a treatment for mild cases of narcolepsy.

Adult↗
PubMed1986

Transduction of c-src coding and intron sequences by a transformation-defective deletion mutant of Rous sarcoma virus.

The mechanism of cellular src (c-src) transduction by a transformation-defective deletion mutant, td109, of Rous sarcoma virus was studied by sequence analysis of the recombinational junctions in three td109-derived recovered sarcoma viruses (rASVs). Our results show that two rASVs have been generated by recombination between td109 and c-src at the region between exons 1 and 2 defined previously. Significant homology between td109 and c-src sequences was present at the sites of recombination. The viral and c-src sequence junction of the third rASV was formed by splicing a cryptic donor site at the 5' region of env of td109 to exon 1 of c-src. Various lengths of c-src internal intron 1 sequences were incorporated into all three rASV genomes, which resulted from activation of potential splice donor and acceptor sites. The incorporated intron 1 sequences were absent in the c-src mRNA, excluding its being the precursor for recombination with td109 and implying that initial recombinations most likely took place at the DNA level. A potential splice acceptor site within the incorporated intron 1 sequences in two rASVs was activated and was used for the src mRNA synthesis in infected cells. The normal env mRNA splice acceptor site was used for src mRNA synthesis for the third rASV.

Avian Sarcoma Viruses↗
PubMed1986

[A case of multiple liver metastases from sigmoid carcinoma treated successfully with arterial infusion chemotherapy].

A 63-year-old female, who had undergone sigmoidectomy for sigmoid carcinoma one year before, was admitted for multiple liver metastases. A urokinase-immobilized catheter was introduced into the proper hepatic artery via the gastroepiploic artery operatively. A daily arterial infusion of 5-FU (250 mg) was combined with a weekly arterial infusion of adriamycin (30 mg) or MMC (10 mg). After discharge, 5-FU (200 mg/day) was given orally and MMC (10 mg) was infused intraarterially every other week at an outpatient clinic. ADR or MMC was infused with angiotensin II, known to increase arterial blood supply to a malignant lesion. Ultrasonography demonstrated 35 to 50% reduction in tumor diameter. The density of metastases seen in computerized tomography became low indicating tumor necrosis. Plasma CEA level, which had initially been as high as 864 ng/ml, decreased rapidly and has remained within normal limits up to the present time. Arterial infusion chemotherapy using 5-FU, ADR or MMC in combination with angiotensin II seems to be effective in the treatment of multiple hepatic metastases from colorectal carcinoma.

Adenocarcinoma↗
PubMed1985

Marked episodic elevation of cerebrospinal fluid pressure during nocturnal sleep in patients with sleep apnea hypersomnia syndrome.

The CSF pressure was measured continuously at the lumbar level during nocturnal sleep in 3 patients with sleep apnea hypersomnia syndrome. Nocturnal sleep was very unstable with frequent episodes of obstructive sleep apnea. When the patients were awake and relaxed in the supine position, their CSF pressure was stable and within the normal range. Episodic marked elevations of CSF pressure occurred frequently during sleep, and each elevation was preceded and accompanied by an episode of sleep apnea or hypopnea. Significant correlations were found between the duration of apneic episodes and increase of CSF pressure, and between decrease of SaO2 or TcPO2 and increase of CSF pressure. The duration of sleep apnea was longer, increase of CSF pressure was greater, and decreases of SaO2 and TcPO2 were more marked during REM sleep than during NREM sleep. It is suggested that the frequent marked episodic elevations of CSF pressure are caused by an increase in the intracranial vascular volume occurring mainly in response to transient hypercapnia and hypoxia, which are induced by pulmonary hypoventilation during the episodes of sleep apnea.

Adult↗