Biomedical subjects

T Nagase

Publications and source records attributed to T Nagase.

At least 253 records · Page 14Linked to original sources

PubMed1982

[Drug sensitivity test of cultured human cancer cells--assay for microcolonies inhibition test].

The sensitivity of anti-cancer drugs against cultured human lung cancer cells and the first cultured xenograft tumor has been measured by the microcolonies inhibition test in microplates (Falcon, Micro Test II). The results obtained were as follows; 1). The drug sensitivity of cancer cells has differed in each case. The established cancer cell lines of the same cell type and the same growth speed have also showed a different sensitivity. Therefore, it suggests that the measurement of drug sensitivity of cultured human cancer cells is usefull for the clinical application. 2). The drug sensitivity of cancer cells has been elevated when they changed their character during the passage cultures. On the other hand, the successful culture of cancer cells has been elevated when they were purified with discontinuous density gradients and a hypotonization. 3). In future, further efforts to develop a better medium for the colonies inhibition test, i. e., a conditioned medium containing the specific growth factor for the colony of cancer cells are imperative.

Animals↗

PubMed1981

Antidiuretic activities of substance P and its analogs.

Substance P (SP) and analogs, including 5 nucleoside (ARA or HRA)-peptides, were examined for antidiuretic activity in ethanolized rats. The activity was potent in the analogs embodying the C-terminal hexapeptide, weak in the nucleoside-pentapeptide, and negligible in the nucleoside-tetrapeptide. In addition, the activity was increased by acylation of the hexapeptide. The antidiuretic potencies were also compared with the hypotensive potencies.

Animals↗

PubMed1981

[Effects of ifenprodil on lateral vestibular nucleus neurons in the cat (author's transl)].

Electrophysiological studies were performed to elucidate effects of ifenprodil, an antivertigo drug, on neuron activity in the lateral vestibular nucleus (LVN) of cats anesthetized with alpha-chloralose. LVN neurons were classified into three types, according to the response pattern upon vestibular nerve stimulation: monosynaptic, polysynaptic I and polysynaptic II neurons, which fired spikes with the mean latencies of 1.07 +/- 0.12 (n = 6), 2.20 +/- 0.19 (n = 8) and 16.37 +/- 2.11 msec (n = 7), respectively. Intravenous administration of ifenprodil up to 5 mg/kg did not affect spike generation of monosynaptic neurons. Spike generation of polysynaptic I and II neurons was dose-dependently inhibited by ifenprodil up to 1 mg/kg. However, increasing doses of the drug up to 5 and 10 mg/kg produced complex effects such as an enhancement of the inhibitory effect in some neurons or a facilitation of responses in others. These results indicate that ifenprodil acts on the polysynaptic I and II neurons without affecting the monosynaptic neurons. It is likely that a small dose of ifenprodil may directly inhibit polysynaptic neurons and higher doses may indirectly enhance the responsiveness of the neurons, probably as a result of an increase in blood flow in the vertebral artery.

Adrenergic alpha-Antagonists↗

PubMed1978

[Physical dependence liability test of ifenprodil in rats (author's transl)].

A single administration of ifenprodil at the doses of 100, 200 and 400 mg/kg (p.o.), and 50 and 100 mg/kg (i.m.) produced a moderate CNS depression in rats, such as, sedation, ptosis, systemic muscle relaxation and decrease in motor activity. These symptoms appeared dose-dependently and persisted for about 4 hours following administration. In a direct physical dependence test, 5 groups of rats were fed the ifenprodil-admixed food together with drinking water ad libitum for 24 hours daily for 53 approximately 103 days (mean ifenprodil intake, 43--240 mg/kg/day), on the gradedly increased dosage schedule with a dosage level of 0.5 vs. 1 mg/g food to 4 mg/g food. In the natural withdrawal following administration, no significant withdrawal signs were observed in any group. In a substitution test either for phenobarbital or morphine, no suppression of withdrawal signs during the period of cross-administration of ifenprodil and no maintenance of dependence were observed. In a physical dependence-producing test, the rats fed ifenprodil never manifested withdrawal signs such as diarrhea, "wet shakes", sudden loss of body weight as in the levallorphan precipitation test. Ifenprodil apparently has no physical dependence liability.

Animals↗

PubMed1977