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Biomedical subjects

H Kubo

Publications and source records attributed to H Kubo.

At least 343 records · Page 19Linked to original sources
PubMed1986

A difference in mode of antagonism between optical isomers of a potent selective alpha 1-adrenoceptor blocker (YM-12617) and norepinephrine in isolated rabbit iris dilator and aorta.

Optical isomers of YM-12617, a potent and selective alpha 1-adrenoceptor blocker, were tested on the rabbit iris dilator and aorta. The order of potency was R(-)-isomer greater than racemate greater than S(+)-isomer. The R(-)-isomer and racemate behaved as an essentially irreversible antagonist to norepinephrine in the iris dilator where the efficacy of norepinephrine was small, although the S(+)-isomer was a competitive antagonist. These drugs behaved as a competitive antagonist of norepinephrine in the aorta where the efficacy of norepinephrine was large.

Adrenergic alpha-Antagonists↗
PubMed1986

[Sensitivity to etoposide in cultured cells from cervical squamous cell carcinoma].

The anti-cancer effect of Etoposide was tested in in vitro in cultures of cells taken from a squamous cell carcinoma of the uterine cervix (SKG-IIIb). Growth inhibition was tested by the regrowth assay method, inhibition of DNA synthesis by the uptake of 3H-thymidine, and morphological changes by the method of Limburg et al. The concentrations of Etoposide used were similar to the blood levels recommended for clinical use. The regrowth assay showed that the effective concentration of Etoposide for 50% cell kill was 7.5 micrograms/ml in 2-hour and 1.0 microgram/ml in 24-hour cultures. The 3H-thymidine uptake test showed that a concentration of 13 micrograms/ml for 2 hours or of 3.5 micrograms/ml for 24 hours resulted in 50% inhibition of DNA synthesis. Morphological changes were much greater in the 2-hour cultures at the higher concentration of Etoposide than in the 24-hour cultures at the lower concentration. Investigation of the drug sensitivity by cell kinetics disclosed prolongation of the cell cycle occurring after 96 hours at 1.0 microgram/ml and inhibition of cell cycle progression occurring after 24 hours at 10.0 micrograms/ml and after 4 or 8 hours at 50.0 mu/ml. Thus, the anti-cancer effect of Etoposide on SKG-IIIb depends on both the concentration and exposure time and is related to its ability to inhibit cell growth and DNA synthesis and to cause morphological changes in the cancer cells.

Carcinoma, Squamous Cell↗
PubMed1985

Water calorimetric determination of absorbed dose by 280 kVp orthovoltage X-rays.

The absorbed dose to water from 280 kVp orthovoltage X-rays was determined by a water calorimeter and compared with that determined by an ionization chamber. X-ray qualities of three different filtrations were investigated: they were characterized by 0.57, 0.695 and 1.76 mm of copper half value layers (HVL). The absorbed dose determined by the calorimeter is found higher by 7-9% than that by an ionization chamber. This difference was greater by 4% than that observed for a 60Co beam with the same two detectors.

Calorimetry↗
PubMed1985

Dosimetry of anterior chest treatment by 10 MV X-rays using a tissue compensating filter.

The dose uniformity of anterior chest treatments resulting from a missing tissue compensating filter has been studied. Patient dosimetry with 10 MV X-rays was simulated using film, an ionization chamber, and thermoluminescent dosimetry (TLD). The results show that the compensating filter greatly improved the dose uniformity of a homogeneous phantom. However, the improvement for an inhomogeneous phantom and for patients was found to be less impressive. When using the filter, the increase in surface dose was found to be clinically insignificant.

Filtration↗
PubMed1985

Rapid method for determination of kanamycin and dibekacin in serum by use of high-pressure liquid chromatography.

A rapid, simple, and accurate method for the determination of kanamycin and dibekacin in serum by use of high-pressure liquid chromatography is described. The serum proteins were precipitated with 3.5% perchloric acid containing sodium octanesulfonate. After centrifugation, a sample of the supernatant was directly injected into the chromatograph. The determination of kanamycin and dibekacin was performed by a combination of reverse-phase, ion-pair chromatography, postcolumn derivatization with o-phthalaldehyde, and fluorescence detection. The correlation coefficients with fluorescence polarization immunoassay were 0.996 for kanamycin and 0.957 for dibekacin.

Chromatography, High Pressure Liquid↗