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Biomedical subjects

Y Kohda

Publications and source records attributed to Y Kohda.

At least 73 records · Page 4Linked to original sources
PubMed1985

Effects of cardioplegia on myocardial metabolism during hypothermic ischemia--components and mode of administration.

Isolated rat heart preparations were used to determine the effect of cardioplegia on myocardial metabolism during profound hypothermic (15 degrees C) ischemia. The hearts were grouped according to the components of cardioplegia and the mode of administration. The six groups were normokalemic (GI), calcium-containing hyperkalemic (GII), calcium-free hyperkalemic (GIII) and single dose (A), multidose (B). Following 120 min of ischemia, tissue ATP decreased from 25.4 +/- 2.2 to 10.3 +/- 2.7, 3.9 +/- 2.4, 4.1 +/- 1.2, 15.5 +/- 3.2, 14.5 +/- 2.4 and 20.0 +/- 2.7 (I-A vs II-A p less than 0.005, I-A vs III-A p less than 0.005, I-B vs III-B p less than 0.05, II-B vs III-B p less than 0.005), and tissue lactate increased from 9.6 +/- 1.5 to 163.4 +/- 12.0, 174.1 +/- 13.5, 166.8 +/- 21.3, 99.1 +/- 8.3, 102.6 +/- 12.2 and 83.5 +/- 9.3 (I-B vs III-B p less than 0.02, II-B vs III-B p less than 0.02) mumol/dry wt g, in GI-A, GII-A, GIII-A, GI-B and GII-B, respectively. The results of this study suggests that (1) potassium cardioplegia in a single dose does not prevent degradation of high energy phosphate (HEP) in the hypothermic arrested heart, (2) though multidose cardioplegia is effective in preserving HEP during ischemia, the extent of its effects varies with the composition, and (3) the omission of calcium is beneficial in GIK cardioplegia in terms of preserving HEP at the end of ischemia.

Adenine Nucleotides↗
PubMed1984

Determination of pemoline in plasma, plasma water, mixed saliva, and urine by high-performance liquid chromatography.

A new determination method of pemoline in plasma, plasma water, mixed saliva, and urine using high-performance liquid chromatography was developed. The detection limit of pemoline using 0.2 ml of the sample was 0.02 microgram/ml in plasma, plasma water, saliva, and urine. The recoveries of pemoline added to plasma, saliva, and urine (each 6 micrograms/ml) were more than 98%. The coefficients of variation of within-run and between-run precisions for 5 concentrations of pemoline in plasma were less than 5 and 6%, respectively. The elimination half-lives of pemoline obtained from the plasma concentration-time curves after a single oral administration of pemoline in two subjects were 6.7 and 10.3 h. Mean values of the ratio between saliva and plasma total concentration in two subjects were 0.55 and 0.64, and mean values of plasma protein binding percent were 35.7 and 25.2%, respectively. The saliva concentrations were in proportion to the plasma unbound pemoline concentrations at simultaneous samplings, and the ratios between saliva and plasma unbound concentration were about 0.9 in two subjects. Usefulness of saliva in the estimation of plasma protein-unbound pemoline concentration was noted.

Adult↗
PubMed1984

Peripheral arterial disease diagnosed with high-count-rate radionuclide arteriography.

Thirty-seven patients with peripheral vascular disease involving the legs were studied with first-pass peripheral radionuclide arteriography (RNA) and contrast arteriography to determine whether RNA could be used to evaluate perfusion of the toes. Data were acquired for 100 seconds using a multicrystal gamma camera following bolus injection of 30-35 mCi (1,110-1,295 MBq) of Tc-99m-labeled albumin during reactive hyperemia. Peripheral time-activity curves were examined and the time required for activity to decline to 75% of peak activity ( T75 ) was recorded. When an abnormal RNA was defined as T75 greater than or equal to 50 seconds, sensitivity was 92%, positive predictive accuracy 100%, and negative predictive accuracy 75%. These data suggest that peripheral RNA of the toes is a reliable, noninvasive procedure for evaluation of peripheral arterial disease; it can be valuable as a screening test prior to contrast arteriography as well as for follow-up.

Adult↗
PubMed1983

Effect of diltiazem on functional recovery and myocardial metabolism during hypothermic global ischemia and normothermic reperfusion.

An isolated working rat heart preparation was used to determine the effect of diltiazem, a calcium antagonist, on the myocardial metabolism and functional recovery in the ischemic and reperfused heart, under conditions of 15 degrees C of topical hypothermia. The hearts were divided into two groups according to the solution injected into aortic root at the onset of ischemia. Group I (25 hearts) were given 3 ml of cold Krebs-Henseleit bicarbonate buffer solution (KHB), and Group II (25 hearts) were given the same dose of KHB containing 300 micrograms of diltiazem. After 30 min of reperfusion following 120 min of ischemia, cardiac output (ml/min) was significantly better in Group II (24.1 +/- 3.2) than in Group I (9.5 +/- 2.5). There were no differences between the groups with regard to tissue levels of creatine phosphate, adenosine triphosphate (ATP), total adenine nucleotide (TAN), glucose-6-phosphate and lactate during the ischemia. However, ATP and TAN levels were significantly higher in Group II after 30 min of reperfusion. These data show that, although diltiazem has little effect in preventing the catabolism of high-energy phosphates during hypothermic ischemia, there was an improvement in myocardial metabolism and an enhanced functional recovery during reperfusion in the diltiazem-treated hearts.

Adenine Nucleotides↗
PubMed1983

Bioavailability of phenytoin on single and multiple oral doses of two dosage forms in normal subjects.

The extent and rate of absorption of phenytoin (PHT) from tablet and powder were studied in four healthy adult volunteers. It was demonstrated by urinary and fecal excretion that the almost all quantity of PHT in tablet was absorbed through the gastrointestinal tract, and the observed values of the estimated free concentration (Cest.f) estimated from mixed saliva concentration of PHT in the multiple dose were in fair agreement with the calculated values of that by using computer simulation in case of tablet. On the contrary, the variations were observed in Cest.f using therapeutic dose of PHT powder. The values of Cest.f at steady-state in tablet administration were higher than those in powder administration. The absorption ratio of PHT powder was low and variable, and decreased upon increase of dose. The ratio calculated from the Cest.f values of both dosage forms at steady-state were in good correspondence to the observed values of PHT excreted in feces.

Adult↗
PubMed1983

Comparison of bioavailability for phenytoin products prepared by wet granulation in normal subjects and epileptic patients.

A 20% phenytoin (PHT) plain mixture with excipients (20%PM) and three PHT products prepared by wet granulation, which are 20% fine granule (20%FG), 99% air-dried fine granule (99%FG-A) and 99% freeze-dried fine granule (99%FG-F), were prepared. The extents of PHT absorption from these products and the Aleviatin Fine Granules (97%FG) prepared with microcrystalline PHT powder were compared with those from commercially available PHT powder (Aleviatin) and tablet (Hydantol Tablet 25 mg), which are of the Pharmacopoeia of Japan grade, in healthy adult volunteers. In single dose study, the extents of PHT absorption from the powder, 20%PM, 20FG, 99%FG-A, 99%FG-F, 97%FG and tablet were 89.7, 92.2, 99.0, 96.7, 99.1, 99.1 and 99.3%, respectively. The property of almost complete absorption of PHT from the product was shown in the 20%FG, 99%FG-F and 97%FG similar to the tablet. In multiple dose study, the minimum and the average estimated free concentrations of PHT at steady-state for 99%FG-F and 97%FG were nearly equal to those for the tablet, and were higher than those for the powder. In epileptic patients, the plasma PHT concentrations were increased when dosage form was changed from the powder to 99%FG-F. However, the plasma PHT concentrations were scarcely altered when dosage form was changed from the tablet to 99%FG-F. The change in dosage forms from the tablet to 99%FG-F and 97%FG or opposite direction can be done without causing toxicity in epileptic patients, so long as these products are used at the same amounts as PHT.

Adolescent↗
PubMedDate not supplied

Plasma lidocaine, monoethylglycinexylidide, and glycinexylidide concentrations after epidural administration in geriatric patients.

BACKGROUND AND OBJECTIVES: The purpose of this study was to evaluate the effect of age on the pharmacokinetics of lidocaine after epidural administration. METHODS: Two percent lidocaine with epinephrine (5 microg/mL) was administered in two different age groups: an adult group (age 42 +/- 6 years, n = 10) and an elderly group (age 77 +/- 4 years, n = 10). Concentrations of lidocaine and its active metabolites, monoethylglycinexylidide (MEGX) and glycinexylidide (GX), were measured in plasma samples obtained after 15, 30, 45, 60, 90, 120, 150, and 180 minutes of administration using high-performance liquid chromatography with ultraviolet detection. RESULTS: No significant differences in plasma concentrations of lidocaine and its metabolites were observed between the two groups during the 3 hours of study. However, the elderly group showed significantly longer mean residence times (MRTs) and lower plasma clearance of lidocaine during the period compared with the adult group (P < .05). Plasma concentration ratios of MEGX/lidocaine were significantly lower in the elderly group after 2 hours of lidocaine administration (P < .05). CONCLUSIONS: The increase in plasma lidocaine concentration after epidural anesthesia in elderly patients was not as high as anticipated. However, the elderly patients showed longer MRTs, lower clearance, and lower ratios of MEGX/lidocaine than did the adult (middle-age) patients.

Adult↗