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Biomedical subjects

T Seki

Publications and source records attributed to T Seki.

At least 685 records · Page 38Linked to original sources
PubMed1980

Nucleotide sequence of a cloned fragment of rat mitochondrial DNA containing the replication origin.

The nucleotide sequence was determined for the 717 bp HapII subfragment (HapEcoA5) of the EcoRI-A fragment of rat mitochondrial DNA, which contains the heavy-strand replication origin. Analysis of the heavy-strand initiation segments released from the D-loop molecules has revealed that some 5'-ends of these initiation segments are linked to ribonucleotide(s) and are heterogeneous. Sequence analysis of the 5'-end portion of the initiation segment indicated that one of the start points of the deoxyribonucleotide polymerization corresponds to the 425th bp on the HapEcoA5. Two-fold rotational symmetry and palindrome structures, and a G-cluster sequence around the start point have been discussed in connection with unidirectional replication.

Animals↗
PubMed1980

Pharmacokinetic studies on nicardipine hydrochloride, a new vasodilator, after repeated administration to rats, dogs and humans.

1. Various doses of [14C]nicardipine HCl were administered orally at different intervals for different periods to rats and dogs, and cumulative excretion, plasma concn. of unchanged drug, plasma clearance, tissue distribution, and AUC determined. 2. Plasma concn. in 12 patients with cerebrovascular disease receiving 20 mg three times per day for 28 (6 patients) or 365 days (6 patients) was determined on various days 1 h after the third dose. 3. In tissues of rats receiving 3 mg/kg/day for 21 days, distribution 1 h after administration on day 14 was 1.4-2.5 times higher than on day one; there was no statistical difference between day 14 and 21, suggesting that a steady state had been established within 14 days. 4. In rats receiving 3 mg/kg/day for seven days, cumulative excretion was 97.3% administered drug, indicating no tendency to accumulation. 5. Doses of 10 mg/kg three times at 3 h intervals to dogs significantly increased the plasma concn. on repeated administration, but this was not the case if the drug was administered at 6 h intervals or if the dose was decreased to 2 mg/kg. These non-linear pharmacokinetics may be ascribable to saturation of the hepatic drug-metabolizing enzyme activity. 6. In dogs given 5 mg/kg three times per day at 3 h intervals for seven days, max. plasma concn. and AUC on day 4 were 1.8 and 1.6 times higher, respectively, than on day 1. On days 4 and 7, these values were similar, suggesting that a steady state had been established within 4 days. 7. In six patients receiving the drug for 28 days, the mean plasma concn. on day 1, 7, 14, and 28 was approx. 0.1 microgram/ml, similar to the value on day 365 in the other six patients. This indicates that during long periods of administration, the plasma concn. of the drug shows no tendency to increase.

Adult↗
PubMed1980

West syndrome and Lennox-Gastaut syndrome: a survey of natural history.

The West syndrome and the Lennox-Gastaut syndrome are characterized by their onset in infancy and early childhood, intractable seizures occurring almost daily, severe psychomotor retardation, and poor prognosis. Among handicapped children, they offer the most serious problems in daily care at home or in institutions because of frequent attacks and marked retardation. A nationwide survey in Japan was performed to elucidate the natural history of these two syndromes.

Adrenocorticotropic Hormone↗
PubMed1980

[Experimental and clinical study of safe prolongation of tourniquet time by hypothermia of an upper limb (author's transl)].

UNLABELLED: In order to establish a practical method by which the tourniquet can be safely kept on for more than 2 hours, i.e., the safe limit in the conventional method, the author initially made an experimental and then a clinical investigation as follows. EXPERIMENT: Thirty-five adult mongrel dogs were used including a control group. One hour immersion of hind limb in ice water lowers the temperature of leg muscles from ca. 38 degrees C to 16 degrees--18 decrees C. Thereafter, maintenance of tourniquet exsanguination of the cooled hind limb for 5 hours elevates the muscle temperature several degrees, but still keeps it much lower than in the control group. Edema and limping appeared after release of the tourniquet and subsided much faster in the cooled group than in the control group. Result in 12 CASES: Cooling of an upper limb after general anesthesia or nerve block with ice bags for 30 minutes lowers the temperature of the forearm muscles from 30 degrees--35 degrees C to 16 degrees--25 degrees C. Tourniquet applied thereafter at the upper arm was kept inflated maximally for four hours and 7 minutes. An average of 3 hours and 30 minutes did not cause any serious side effects but only temporary dysesthesia at the finger tips in 2 cases and a Tinel's sign at the site where tourniquet was applied in one case. CONCLUSION: These results proved that tourniquet time could be safely prolonged for 4 hours. The most important problem in the future is to clarify how far it can be safely prolonged.

Adolescent↗
PubMed1979

Simple method for the simultaneous determination of noradrenaline, dopamine and serotonin by stepwise elution from a short column of weak cation-exchange resin.

A simple method for the simultaneous determination of noradrenaline, dopamine and serotonin using a short column of Amberlite CG-50 is described. Noradrenaline and dopamine were eluted from the column with phosphate buffers containing 1.5 and 4.0% boric acid, respectively, and then serotonin was eluted with 1.0 N HCl. Catecholamines were determined by a modification of the ethylenediamine condensation method using potassium ferricyanide as oxidant and isobutanol for extraction of the fluorophores. Serotonin was measured by the acidic o-phthalaldehyde method. The method was applied to the simultaneous determination of noradrenaline, dopamine and serotonin in discrete regions of rat brain.

Animals↗
PubMed1979

RNA-linked nascent DNA pieces in phage T7-infected Escherchia coli. II. Primary structure of the RNA portion.

Short DNA chains were purified from phage T7 infected E. coli cells and 5' ends were labeled with 32P. By an alkali-treatment, pNp's rich in pAp and pCp were liberated from the T7 short DNA chains. After digestion of the [5'-32P] short DNA with the 3' to 5' exonuclease of T4 DNA polymerase, [5'-32P] mono- to pentaribonucleotides tipped with a deoxyribonucleotide residue at their 3' ends were isolated. 5' terminal ribonucleotides were; exclusively AMP in the penta- and the tetraribonucleotides, mostly CMP in the triribonucleotide and mainly CMP and AMP in di- and monoribonucleotides. The 5' terminal dinucleotide of the penta- and the tetraribonucleotides was pApC. The nucleotide sequence of the tetraribonucleotide was mainly pApCpCpN and some pApCpApN, where N was mainly A and C. These results indicate that oligoribonucleotides shorter than trinucleotide may result from in vivo degradation of the tetra- and pentaribonucleotides. A possibility that the tetra- and pentaribonucleotides with a 5' triphosphate terminus are the intact primers for the discontinuous T7 DNA replication is discussed.

Base Sequence↗
PubMed1979

Estimation of catecholamines in human plasma by ion-exchange chromatography coupled with fluorimetry.

Estimation of catecholamines in human plasma was made by ion-exchange chromatography coupled with fluorimetry. Catecholamines in deproteinized plasma were adsorbed onto Amberlite CG-50 (pH 6.5, buffered with 0.4 M phosphate buffer) and selectively eluted by 0.66 M boric acid. The catecholamine fraction was separated further on a column of Amberlite IRC-50 which was coupled with a device for the automated performance of the trihydroxyindole method (epinephrine and norepinephrine) or the 4-aminobenzoic acid-oxidation method (dopamine). One sample could be analysed within 25 min with either method. The lower detection limits were 0.02 ng for epinephrine and dopamine, and 0.04 ng for norepinephrine. Plasma catecholamine contents of healthy adults at rest were epinephrine 0.07 +/- 0.01 ng/ml (n = 19), norepinephrine 0.27 +/- 0.03 ng/ml (n = 19) and dopamine 0.22 +/- 0.03 ng/ml (n = 26). The procedure of adsorption and elution of the plasma catecholamines by ion-exchange resin was simple, the simplicity contributing to constant recovery. The catecholamine fraction could be analysed without evaporation of the eluate. The analytical column could be used for the analysis of more than 1000 samples before excessive back-pressure developed. Our method of continuous measurement of plasma catecholamine fulfils clinical requirements.

Catecholamines↗