In this 30-day study, the distribution and excretion, and the biological - (B.H.T.) of chromium in selected organs of the rat were studied and the results obtained showed a characteristic difference between hexavalent (Cr VI) and trivalent (Cr III) chromium compounds.
The rate of retention at the site of a single injection of Cr III was 88.7% (after 24 hrs) whereas that of Cr VI was 6.4%. After the administration of Cr VI, 232.73 μg or 36% of the total chromium injected was excreted into the urine within 7 days while 48.45 μg or 8.0% was excreted after Cr III administration. The amount of chromium excreted in the feces within 7 days after the injection of Cr VI was 89.17 μg or 13.9%, while the amount of chromium excreted was 146.96 μg or 24.2% of the Cr III administered.
The results of calculation of B.H.T. in several organs after a single administra-tion of Cr VI were as follows. The lung showed two components represented by two kinds of regression lines. The calculated B.H.T. was 60.2 hours (2.5 days) and 501.6 hours (20.9 days). The liver showed three components, 2.4 hours, 52.8 hours and 376.2 hours (15.7 days) ; the kidney had two components, 52.8 hours and 250.8 hours (10.5 days); the brain also showed two components, 4.4 hours and 231.52 hours (9.6 days); the heart showed two components, 66.9 hours and 334.42 hours (13.9 days) ; the testis also showed two components, 4.58 hours and 300.9 hours (12.5 days); and the blood had only one component, 334.4 hours (13.9 days).

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Context-sensitive half-times (CSHTs) of fentanyl in dogs were determined using pharmacokinetic models reported by Murphy et al. and Sano et al., and compared with a human model. The CSHT was defined as the time required for a 50% decrease in drug concentration in the central compartment after the termination of infusion. Although CSHTs increased gradually as the infusion time increased, the CSHTs in dogs were shorter than those in humans. The CSHTs at steady-state were 31.3 and 69.2 min in dogs, and 306.5 min in humans. The CSHTs of fentanyl in dogs are apparently shorter than those in humans; therefore, a continuous infusion of fentanyl may be a rational regimen in dogs, even if duration of infusion is extended.

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Although biological half-times of metals in an organ or the total body have been calculated in animal experiments in which a metal is administered and the reduction of the metal in the organ or total body measured, the present study attempts to estimate biological half-times of cadmium in the organs and total body of humans by the observed accumulation of cadmium according to age. In this study the biological - of cadmium in the organs, par- ticularly the kidney, and in the total body, were estimated to be much longer than results obtained from animal experiments. However, biological half-times estimated in this study vary greatly according to the amount of daily exposure to cadmium, sex, age, and certain other factors. The validity of the method used in this study needs further verification.

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This study investigated the relationship between aerobic fitness and repeated sprint ability (RSA) before and after a -. Thirteen male volunteers (23±2 years, 175±5 cm, 67±6 kg; [mean±standard error]) participated in this study. All subjects underwent two laboratory tests on a cycle ergometer. An initial test was conducted to determine aerobic fitness. On separate day, the RSA test was conducted. The RSA exercise comprised 15×6-s sprints with 54-s recovery periods. This was duplicated after a 15-min -. The blood lactate (Bla) removal rate was calculated using Bla values before and after the -. As a result of aerobic fitness, seven subjects were classified as fit (≥58 ml/kg/min) and six as unfit (<58 ml/kg/min). The maximal peak power was significantly reduced in the unfit group (p<0.05) but not in the fit group (p>0.05) at the second session. The change in maximal peak power between sessions was significantly correlated with VO₂max (r=0.714, p<0.01). A strong correlation was observed between Bla removal rate and VO₂max (r=0.830, p<0.01). These results indicate that aerobically fit subjects recover more quickly after RSA exercise due to superior lactate removal ability.

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Flash method and Periodic heating method, that are representative thermal diffusivity measurement methods, require blackening on surface of a sample to improve measurement accuracy. But to add blackening layer on surface of a sample changes measured thermal diffusivity that is apparent value. To obtain accurate thermal diffusivity from measurement result of blackening sample, change of apparent thermal diffusivity attributed blackening layer should be estimated. To estimate apparent thermal diffusivity measured by Flash method,

method using temperature raise curve obtained by simulation model is used. Validity of simulation model is ensured by fitting theoretical temperature rise curve against it. To estimate apparent thermal diffusivity measured by Periodic heating method, phase delay of temperature response obtained by simulation model is calculated. As a result, the larger thickness of blackening layer is, the lower apparent thermal diffusivity of blackening sample is in both of Flash method and Periodic heating method. The result of Flash method has influence of blackening layer more than Periodic heating method.

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実験により重金属の生物学的半減期（BHT）を求める方法で, 短いBHTを報告した研究は多数ある. 一方, 土屋と杉田はヒトの臓器や組織中のガドミウム（Cd）蓄積量により, 微分方程式を含有する非線型回帰法を使用して長いCdのBHTを算出し, それを初めて報告した. それによると腎皮質と髄質（男, 女）のCdのBHT（点推定値）の範囲は12.1－22.7年であった. このデータを使用して, 推定母数の95%信頼限界上のCdのBHTの最小値と最大値を6.9－70.2年と推定した. さらに, そのCdのBHTの個人値の95%信頼限界はおおよそ数年から100年以上の広い範囲内にあると推測された. このようなBHT個人値の広範囲の理由はCdの摂取量, 吸収率や排泄率等の固体差がかなり大きいと考えられていることである. 一方, それらの固体差を無視した平均値として, 蓄積量をもとにしたCdのBHTの点推定値が算出される. したがって, Cdの労働環境や食品の安全基準の算出にその点推定値としてのBHTを使用することは不適当である. このことは, 金属のBHTを慎重に評価吟味して, 軽率な使用を慎むべきであることを示している.

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特に心室性不整脈に有効とされるDisopyramide(Rhythmodan(R))の血中濃度を経時的に測定し,腎機能との関連において本剤の動態を検討した.
対象は内因性クレアチニン・クレアランス(CCr)によって3群に分けた.また本剤の血中濃度変化に対する血液透析の影響をも検討した.各群8時間以降指数関数的に時間とともに血清濃度は降下し,排泄係数(eliminationconstant)は腎機能が低下するほど小であった.また血中半減期T1/2はCCrと全体で有意の負の相関を示し(r=O.61,p<0.O1),腎機能が低下するほど延長していた.2μg/ml前後の血清濃度では血液透析によってあまり影響を受けなかった.

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Two-dimensional echocardiographic (2-D) planimetry and the Doppler pressure - (PHT) method have been used to estimate mitral valve area (MVA) in patients with mitral stenosis (MS). Recently, the proximal isovelocity surface area (PISA) method has been shown to be accurate for calculating MVA. The purpose of this study was to compare the PISA method with previous methods.Thirty patients with MS were studied; 17 had pure MS, 4 combined mild MR, 6 combined mild AR, and 3 combined MR and AR.Color Doppler flow mapping was performed at an aliasing (blue-red interface) velocity of 14cm/sec using the zero-baseline shift.MVA was calculated as 2×3.14×R²×14×(Θ/180)/PFV, where R is the distance from aliasing to orifice, 14 is the aliasing velocity, Θ is the internal angle of the mitral valve, and PFV is the peak flow velocity at the mitral orifice. MVA was also calculated using the 2-D and PHT methods, and compared with the PISA method.MVA calculated using the PISA method correlated well with the 2-D (r=0.90, p<0.01, SEE=0.18cm²) and PHT methods (r=0.82, p<0.01, SEE=0.24cm²). Compared with the 2-D method, the standard error of the estimate of the PISA method was -0.14±0.18cm² and the percent error was -10.4±18.9%. Compared with the PHT method, the standard error of the estimate of the PISA method was+0.01±0.24cm² and the percent error was +3.4±34.6%.MVA calculated using the PISA method correlated well with the 2-D and PHT methods in patients with pure MS or with MS combined mild regurgitation. The PISA method may be useful for calculating MVA as an alternative method.

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持続輸注は凝固因子活性レベルを一定に保つことができ安全で経済的な方法といわれているが, 止血管理するための基準となるクリアランス値の設定も問題の一つとして挙げられる. 今回クリアランスの理論値として2.5単位／kg／hrを用いて27例30関節の人工関節置換術の止血管理を行い, 実際のクリアランス値の経時的変化を検討した. 今回行った27例の注入試験の回収率(108％)や半減期(10.8時間)結果は, この理論値に矛盾しなかった. クリアランス値は手術開始時2.84単位／kg／hr, 術後13日目で1.75単位／kg／hrであった. 第VIII因子活性はそれぞれ120％と100％であり, これは目標とした凝固因子活性レベルより高めであった. 凝固因子製剤は溶解後最長24時間室温で放置されていたが因子活性の低下はなかったことから, 持続輸注による整形外科大手術はクリアランス理論値を考慮し行えば安全に行える方法である.

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Ionescu-Shiley弁を用いてMVRを施行した48例を対象として, 断層心エコー図・ドブラー法を用いて, 弁の経年変化について追跡した。その結果, 1. 明らかな弁尖肥厚は, 3年で4%, 4年で12.5%, 5年で38%, 6年で47%, 7年では61%の症例で認められた。2. 左室流入速度は1.0～1.5m/sであり, 正常に機能している限り, 不変であった。3. PHTは1年で84.2±21.9, 2年で86.7±15.8, 3年で9.1.0±17.4, 4年で99.3±29.7, 5年で101.3±24. 5, 6年で112.5±22.5, 7年で100.0±18.3msecと徐々に延長した。4. 弁機能不全を有する場合, 逆流を有する例では流入速度は速いが, PHTは正常であった。狭窄を有する例では, 流入速度が速く, かつPHTも延長していた。
Ionescu-Shiley弁の機能不全の診断では, 超音波ドプラー法が有用であり, 流入速度とPHTを計測することにより, 逆流と狭窄の定量的評価が可能である。

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Urinary Cadmium (Cd) levels were measured twice a year from 1986 to 1992 in five workers exposed to cadmium pigment dust. At the end of 1987, the work environment was improved, and urinary Cd was monitored in association with atmospheric Cd. The five subjects were exposed to cadmium dust at maximum concentrations of 0.857 mg/m³ and 0.045 mg/m³, before and after the improvement, respectively. By arbitrarily setting the urinary Cd level of each worker before improvement at 100, the values after improvement ranged from 41.7 to 94.6, yielding no significant difference. Although the environmental level of Cd was decreased by ten-fold or more, no significant decrease in urinary Cd could be detected.

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By means of human growth hormone-releasing hormone (hGHRH)-RIA using an antiserum directed toward the C-terminal region of hGHRH-(1-44)-NH₂, the plasma disappearance - and metabolic clearance rate (MCR) of immuoreactive hGHRH (IR-hGHRH) were examined in normal subjects after an iv bolus injection of synthetic hGHRH-(1-44)-NH₂ (1 μg/kg BW). The disappearance of IR-hGHRH from plasma was characterized by a biexponential decay curve, with initial distribution and subsequent metabolic t1/2 value of 5.0±1.0 and 29.6±5.4 min (mean±SE), respectively. The MCR of IR-hGHRH was 6.1±1.2 ml/min·kg. The volume of distribution of IRhGHRH was 3.3±0.4 liters. The molecular size of the plasma IR-hGHRH was not different from that of hGHRH-(1-44)-NH₂ for at least 90 min after the injection of hGHRH-(1-44)-NH₂ when examined by gel-filtration chromatography. This prolonged clearance of hGHRH from human plasma relative to that of other hypothalamic hormones may in part explain the sustained plasma GH rises after hGHRH injection in man.

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本研究では，異なるハーフタイム戦略が反復性スプリントパフォーマンス （RSA） に与える影響を検討した．10名の男子サッカー選手は，4試行の無作為化交差試験を実施した．本試験では， 15分間のハーフタイムを挟む2回 （前・後半） のRSAテスト （6秒スプリント- 24秒レストを6セット） を行った．4条件のハーフタイムの介入は，1） 安静座位 （CON試行），2） ジャケット着用 （PAS試行），3） リウォームアップ実施 （ACT試行），4） PASおよびACT介入の併用 （COMB試行） のいずれかとした．後半の平均・最高走速度はCON試行で前・後半間に有意差が認められ，後半は低値であったが （p<0.05），他の試行では前・後半間の有意な差は認められなかった．後半中の胃腸温，筋電図，筋酸素動態には試行間の有意な差は認められなかった． 後半開始時の平均皮膚温には試行間の有意差が認められ （p<0.05），CON試行と比較し，COMB試行は高値であった．後半の心拍数には試行間の有意な差が認められ （p<0.05），CONおよびPAS試行と比較し，ACTおよびCOMB試行は高値であった．従って，本研究で用いたいずれかの介入を行うことでRSA低下を防止できることが示唆された．

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本研究の目的は，暑熱下における運動間の休息中に行う身体外部・内部冷却の併用が高強度運動パフォーマンスに与える影響を検討することであった．6名の若年男性を対象に，暑熱下における2試行の無作為化交差試験を実施した．本試験では，15分間の運動間の休息 （ハーフタイム） を挟む，30分間の自転車運動を2回 （前・後半） 行った．ハーフタイムでは，安静座位 （コントロール試行） またはクーリングベストの着用・体重当たり5 gのアイススラリーの摂取の併用 （クーリング試行） のいずれかを行った．主評価項目は前・後半終了前5分間のタイムトライアルパフォーマンスとした．運動間の休息中の身体冷却によって，後半のタイムトライアパフォーマンスが高い値で維持された．またクーリング試行の直腸温が後半開始0分，5分，10分で低下した．従って，本研究で用いた身体外部・内部冷却の併用は，運動パフォーマンスの維持・体温の低下の観点から暑さ対策として有効である可能性が示された．

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[Purpose] The purpose of this study was to compare the physiological responses of standing stepping, standing rest, and sitting rest that can be practiced during - during actual competition, and to examine effective ways of spending in the subsequent sprint performance. [Method] The subjects were 14 male university students. First, using the Yo-Yo test, a certain amount of exercise was applied, and three trials of standing stepping, standing rest, and sitting rest were randomly performed for 10 minutes. After that, as a performance test, the time of 20m sprint was measured. Heart rate was measured continuously at all times, and blood lactate level and subjective exercise intensity were measured at rest, immediately after exercise, and 3, 6 and 9 minutes after the end of exercise. [Results] The 20m sprint time of sitting rest and RPE were significantly lower than those of standing rest. The heart rate of sitting rest was significantly lower than that of standing stepping and standing rest. There was no significant difference in blood lactate levels between the three trials. [Conclusion] It was suggested that sitting rest may be recommended as an effective way to spend - in high-intensity intermittent sports.

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