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Biomedical subjects

K Yoshii

Publications and source records attributed to K Yoshii.

At least 73 records · Page 4Linked to original sources
PubMed1995

[Ergocalciferol reference standard (Control 941) of the National Institute of Health Sciences].

The raw material for ergocalciferol was tested for preparation of the "Ergocalciferol Reference Standard (Control 941)". Analytical data obtained were as follows: melting point, 117.6 degrees C; UV and infrared spectra, the same as those for JP Cholecalciferol Reference Standard; specific absorbance, E1%1cm = 458 (265 nm); thin-layer chromatography and high-performance liquid chromatography (HPLC), no impurities were detected, respectively; assay, 100.6% by HPLC. Based on the above results, the candidate raw material was authorized as the Japanese Pharmacopoeia Reference Standard (Control 941).

Chemical Phenomena↗
PubMed1995

[Cholecalciferol reference standard (Control 941) of the National Institute of Health Sciences].

The raw material for cholecalciferol was tested for preparation of the "Cholecalciferol Reference Standard (Control 941)". Analytical data obtained were as follows: melting point, 88.5 degrees C; UV and infrared spectra, the same as those for JP Cholecalciferol Reference Standard (Control 923), respectively; specific absorbance at 265 nm E1%1cm = 471; optical rotation, [alpha]20D = +107.3 degrees; thin-layer chromatography and high-performance liquid chromatography (HPLC), no impurities were detected, respectively; assay, 101.3% by HPLC. Based on the above results, the candidate raw material was authorized as the Japanese Pharmacopoeia Reference Standard (Control 941).

Chemical Phenomena↗
PubMed1995

[Prednisolone acetate reference standard (Control 941) of the National Institute of Health Sciences].

The raw material for prednisolone acetate was tested for preparation of the "Prednisolone Acetate Reference Standard (Control 941)". Analytical data obtained were as follows: melting point, 237.5 degrees C (decomposition); UV and infrared spectra, the same as those for JP Prednisolone Acetate Reference Standard (Control 903), respectively; specific absorbance at lambda max E1%1cm = 379; optical rotation, [alpha]20D = +115.2 degrees; thin-layer chromatography and high-performance liquid chromatography (HPLC), no impurities were detected, respectively; assay, 100.8% by HPLC. Based on the above results, the candidate material was authorized as the Japanese Pharmacopoeia Reference Standard (Control 941).

Chemical Phenomena↗
PubMed1994

Taste responses of bullfrog to pungent stimuli.

Taste responses of bullfrogs to various pungent compounds and taste substances were electrophysiologically recorded from glossopharyngeal nerves. The threshold concentrations were approximately 10(-7) M for piperine, approximately 10(-6) M for capsaicin and approximately 10(-4) M for allyl isothiocyanate. At any concentration examined, piperine was more potent than capsaicin. Both piperine and capsaicin elicited desensitizing responses, but the taste receptors recovered from the desensitization within 10 min after washing with deionized water. Cross-adaptation experiments revealed that capsaicin only partially desensitizes receptors for piperine, L-leucine, HCl or quinine. Perfusion of the lingual artery with a solution containing no added Ca decreased the responses to capsaicin. Such a solution has been shown to suppress the taste nerve responses by blocking synaptic transmissions between taste cells and taste nerves [8]. These results suggest that the gustatory effects of capsaicin are different from its pharmacological effects on sensory neurons. It is likely that capsaicin and other pungent compounds, when they act as seasonings, stimulate taste cells rather than the free nerve endings of the sensory neurons.

Adaptation, Physiological↗
PubMed1994

Phenytoin, an antiepileptic drug, competitively blocked non-NMDA receptors produced by Xenopus oocytes.

The blocking effect of phenytoin (PHT) and other antiepileptic agents on the glutamate receptors was investigated under voltage-clamp conditions using Xenopus oocytes that translated ddY-stock mouse brain mRNA. PHT shifted the concentration-response curve for kainate to right without significant block on the maximum response obtained, indicating that PHT competitively blocks the non-NMDA receptors. An apparent dissociation constant of PHT was 1.9 x 10(-4) M. The block was voltage-independent. Other antiepileptic agents examined hardly blocked the kainate responses except phenobarbital that blocked the responses. The possibility that the competitive block constitutes a part of the antiepileptic action of PHT was discussed.

Animals↗
PubMed1994

Electrophysiological responses of Xenopus oocytes to amino acids: criteria for expression of injected mRNA coding chemoreceptors.

Responses of endogenous transporters/receptors of Xenopus oocytes to L-alanine, L-arginine, L-leucine and L-serine were investigated under voltage clamp conditions. (a) Concentration-response relations for the amino acids followed Langmuir's adsorption isotherm. (b) The neutral amino acids required Na+ to elicit the responses, whereas L-arginine did not. (c) The responses to L-alanine decreased with decreasing pH and became undetectable at pH 5.5. The present experiments supply criteria to judge if the oocytes translate exogenous mRNA coding taste or olfactory receptor proteins for the amino acids, the best characterized stimuli, especially in fishes.

Amino Acids↗
PubMed1994

[The Dexamethasone Reference Standard (Control 931) of the National Institute of Health Sciences].

Raw dexamethasone material was tested for preparation of the "Dexamethasone Reference Standard (Control 931)". Analytical data obtained were as follows: melting point, 245.1 degrees C (decomposition); infrared spectrum, the same as that of the JP Dexamethasone Reference Standard; optical rotation, -alpha-20D = + 76.75 degrees; thin-layer chromatography, two impurities were detected; high-performance liquid chromatography (HPLC), one impurity was detected; loss on drying, 0.14%; assay result, 99.4% by HPLC. Based on the above findings, the raw material was authorized as the JP Dexamethasone Reference Standard (Control 931).

Chemical Phenomena↗
PubMed1994

[The Cyanocobalamin Reference Standard (Control 931) of the National Institute of Health Sciences].

Raw cyanocobalamin material was tested for preparation of the "Cyanocobalamin Reference Standard (Control 931)". Analytical data obtained were as follows: loss on drying, 4.2%; infrared spectrum, the same as that of the JP Cyanocobalamin Reference Standard (Control 901); thin-layer chromatography, four impurities were detected; high-performance liquid chromatography (HPLC), seven to eight kinds of impurities were detected, but the total amount of impurities was only 1.0 +/- 0.52% (n = 5); assay results, 100.6% by spectrophotometry in the JP XII and 99.7% by HPLC. Based on the above findings, the raw material was authorized as the JP Cyanocobalamin Reference Standard (Control 931).

Chemical Phenomena↗
PubMed1994

[The Progesterone Reference Standard (Control 931) of the National Institute of Health Sciences].

Raw progesterone material was tested for preparation of the "Progesterone Reference Standard (Control 931)". Analytical data obtained were as follows: melting point, 131.6 degrees C; infrared spectrum, the same as that of the JP Progesterone Reference Standard; optical rotation, [alpha]D20 = +181.1 degrees; thin-layer chromatography, no impurity was detected; high-performance liquid chromatography (HPLC), trace amounts of two impurities were detected; loss on drying, 0.23%; assay results, 99.4% by UV spectrophotometry in the JP XII and 100.5% by HPLC. Based on the above findings, the raw material was authorized as the JP Progesterone Reference Standard (Control 931).

Chemical Phenomena↗
PubMed1994

[Estradiol Reference Standard (Control 931) of National Institute of Health Sciences].

The raw material for estradiol was examined for preparation of the "National Institute of Health Sciences (NIHS) Estradiol Reference Standard (Control 931)". Analytical data obtained were as follows: melting point, 179.0 degrees C; infrared spectrum, the same as that of the present NIHS Estradiol Reference Standard; optical rotation, -alpha-20D = +80.4 degrees; thin-layer chromatography, no impurity was detected; high-performance liquid chromatography (HPLC), a trace amount of two impurities were detected; loss on drying, 0.24%; assay, 100.4% by UV spectrophotometry and 101.2% by HPLC. Based on the above results, the raw material was authorized as the NIHS Estradiol Reference Standard (Control 931).

Chemical Phenomena↗
PubMed1994

[The Ascorbic Acid Reference Standard (Control 931) of the National Institute of Health Sciences].

Raw ascorbic acid material was tested for preparation of the "Ascorbic Acid Reference Standard (Control 931)". Analytical data obtained were as follows: infrared spectrum, the same as that of the JP Ascorbic Acid Reference Standard; optical rotation -alpha-20D, + 21.4 degrees; melting point, 190.3 degrees C (decomposition); loss on drying, 0.02%; assay result, 100.1% by iodometry. Based on the above findings, the raw material was authorized as the JP Ascorbic Acid Reference Standard (Control 931).

Ascorbic Acid↗
PubMed1994

[The Cyclandelate Reference Standard (Control 931) of the National Institute of Health Sciences].

Raw cyclandelate material was tested for preparation of the "Cyclandelate Reference Standard (Control 931)". Analytical data obtained were as follows: melting point, 57.4 degrees C; ultraviolet spectrum, lambdamax = 252.0, 258.1 and 264.1 nm and E 1cm 1% = 5.85 (252.0 nm), 6.95 (258.1 nm), 5.30 (264.1 nm), respectively; infrared spectrum, the same as that of the JP Cyclandelate Reference Standard; thin-layer chromatography, no impurities were detected up to 1000 micro g; high-performance liquid chromatography (HPLC), no impurities were detected; loss on drying, 0.03%; assay result, 101.4% by HPLC. Based on the above findings, the raw material was authorized as the JP Cyclandelate Reference Standard (Control 931).

Chemical Phenomena↗
PubMed1994

[The Alprostajil Reference Standard (Control 921) of the National Institute of Health Sciences].

Raw alprostajil material was examined for preparation of the "Alprostajil Reference Standard (Control 921)". Analytical data obtained were as follows: infrared spectrum, the same as that of the USP Alprostajil Reference Standard; thin-layer chromatography, no impurities were detected up to 20 micro g; high-performance liquid chromatography (HPLC), no impurities were detected; assay result, 99.6% by HPLC. Based on the above findings, this raw material was authorized as the NIHS Alprostajil Reference Standard (Control 921).

Alprostadil↗
PubMed1994

[The Thiamine Hydrochloride Reference Standard (Control 931) of the National Institute of Health Sciences].

Raw thiamine hydrochloride material was tested for preparation of the "Thiamine Hydrochloride Reference Standard (Control 931)". Analytical data obtained were as follows: melting point, 242.7 degrees C (decomposition); infrared spectrum, the same as that of the JP Thiamine Hydrochloride Reference Standard; thin-layer chromatography, one impurity was detected; high-performance liquid chromatography (HPLC), a trace amount of one impurity was detected; assay results, 100.4% by UV spectrophotometry and 100.0% by HPLC, respectively. Based on the above findings, the raw material was authorized as the JP Thiamine Hydrochloride Reference Standard (Control 931).

Chemical Phenomena↗
PubMed1994

[The Testosterone Propionate Reference Standard (Control 881) of the National Institute of Health Sciences].

Raw testosterone propionate material was tested for preparation of the "Testosterone Propionate Reference Standard (Control 881)". Analytical data obtained were as follows: loss on drying, 0.1%; melting point, 120.6 degrees C; optical rotation [alpha]20D = + 85.4 degrees; ultraviolet spectrum, lambdamax = 241 nm and specific absorbance E 1cm1% (241 nm) = 483; infrared spectrum, the same as that of the NIHS Testosterone Propionate Reference Standard; thin-layer chromatography, no impurities were detected; high-performance liquid chromatography (HPLC), one impurity was detected; assay result, 100.6% by UV spectrophotometry. Based on the above findings, the raw material was authorized as the Testosterone Propionate Reference Standard (Control 881) of the National Institute of Health Sciences.

Chemical Phenomena↗
PubMed1993

Molecular mass determination of low-molecular-mass heparins. Application of wide collection angle measurements of light scattering using a high-performance gel permeation chromatographic system equipped with a low-angle laser light-scattering photometer.

A high-performance gel permeation chromatographic system with on-line low-angle laser light-scattering detection (HPGPC-LALLS) was used to determine molecular masses of low-molecular-mass heparins (LMMHs). Measurements at wide and narrow collection angles were compared and the application of the HPGPC-LALLS method to small molecules, with molecular masses in the range 1000-10,000, was assessed. The molecular mass averages of fractionated heparins and commercially available LMMHs were also determined by ordinary HPGPC analysis using an LMMH molecular-mass calibrant, supplied by the National Institute for Biological Standards and Control for the calibration of columns. The LALLS intensity at the routinely used narrow collection angle (theta col = 1 degree) about doubled at the wide collection angle (theta col = 2 degrees) and the signal-to-noise ratio was improved. The present study thus indicates that wide collection angle measurement of light scattering allows the application of the HPGPC-LALLS method to very small biopolymers of molecular mass < 10,000.

Chromatography, Gel↗
PubMed1993

[Folic Acid Reference Standard (Control 921) of National Institute of Health Sciences].

Folic acid was tested for the preparation of "Folic Acid Reference Standard (Control 921)". The quality of the raw material was examined and compared with the previous Folic Acid Reference Standard (Control 862). Analytical data obtained were as follows: water content, 7.52%; free amines, 0.1%; infrared spectrum, the same as that of the JP Reference Standard; thin-layer chromatography, three impurities were detected; high-performance liquid chromatography (HPLC), two impurities were detected; assay, 101.2% by spectrophotometry at 550 nm and 100.4% by HPLC. Based on the above results, the raw material was authorized as the Japanese Pharmacopoeia Reference Standard (Control 921).

Chromatography, High Pressure Liquid↗