Hemodynamic and oxygen delivery-consumption changes during partial liver resection

The effects of partial liver resection on hemodynamics and the oxygen delivery-consumption relationship were evaluated in ten patients with hepatocellular carcinoma. The cardiac index and oxygen delivery were increased significantly (P 0.05) at 30 minutes after incision, 30min after liver resection and in the recovery room. Oxygen delivery decreased significantly (P 0.05) during liver resection. Oxygen consumption remained low throughout the procedure. We did not discover any flow-dependent change in oxygen consumption. Although our patients persisted a hyperdynamic state throughout surgery, their arterial ketone body ratio remained low. Therefore, it may be necessary to maintain a hyperdynamic state during partial liver resection in order to increase hepatic blood flow.(Iwasaka H, Kitano T, Mizutani A, et al.: Hemodynamic and oxygen delivery-consumption changes during partial liver resection. J Anesth 7: 145–150, 1993)     

Oxygen delivery and consumption in the perioperative period of coronary artery bypass grafting without blood transfusion

The perioperative changes in relationship between oxygen delivery (D¨_{O 2}) and oxygen consumption (V¨_{O 2}) were examined in forty patients who underwent coronary artery bypass grafting (CABG) without blood transfusion. Hemodilution was performed to maintain hematocrit of 19.2 ± 1.8% during cardiopulmonary bypass (CPB). Hemodynamic and metabolic parameters were measured in four stages; before CPB (stage I), after CPB (stage II), after ICU arrival (stage III), and the following day (stage IV). In each stage, there was a strong positive correlation between V¨_{O 2} and D¨_{O 2}. In stage I, a decrease in D¨_{O 2} was met with low V¨_{O 2}, and there was no imbalance between them (r = 0.67, P 0.01). V¨_{O 2} increased significantly in stage II, and this increased V¨_{O 2} was compensated by an increase in D¨_{O 2} sufficiently to meet tissue oxygen demand (r = 0.59, P 0.01). In stage III and IV, the increases in tissue oxygen requirements were met by increases in oxygen extraction ratio (r = 0.81, P 0.01, r = 0.60, P 0.01, respectively) reflected in lowered mixed venous oxygen tension and saturation. From these results, it is assumed that the adequate relationship between V¨_{O 2} and D¨_{O 2} can be maintained in the perioperative period of CABG without blood transfusion.(Mizushima A, Niimi Y: Oxygen Delivery and consumption in the perioperative period of coronary artery bypass grafting without blood Transfusion. J Anesth 4: 313–318, 1990)     

安氟醚和七氟醚对腹部手术机体耗氧量的影响

对比安氟醚、七氟醚两种吸入麻醉药在腹部手术麻醉期间对机体耗氧量（ＶＯ２）的影响。方法选择择期腹部手术病３０例,ＡＳＡⅠ－Ⅱ级,随机分为安氟醚（Ｅ）组和七氟醚（Ｓ）组。记录手术开始前、麻醉吸醚后５ｍｉｎ及手术开始后３０、６０、９０、１２０、１５０ｍｉｎ时的吸入一呼出氧浓度差,分钟通气量,计算ＶＯ２。同时记录呼气末ＣＯ２浓度（Ｅ－ＴＣＯ２）,平均动脉压（ＭＡＰ）、心率（ＨＲ）,体温（Ｔ）,最低肺泡有效     

Extensive Biliary Excretion of the Model Opioid Peptide [D-PEN2,5] Enkephalin in Rats

Purpose. This study was designed to test the hypothesis that the enzymatically stable opioid peptide, [D-pen^2,5] enkephalin (DPDPE), is excreted extensively into bile. Methods. Following an i.v. bolus dose of DPDPE (10 mg/kg) to rats, concentrations of DPDPE in serum, bile, liver homogenate and urine were measured by a novel capillary zone electrophoresis method. Data were analyzed to recover the fundamental pharmacokinetic parameters (volumes of distribution; distribution and elimination rate constants governing DPDPE systemic and biliary disposition). Parallel in vitro experiments were performed to evaluate the partitioning of DPDPE between erythrocytes and plasma, as well as to assess the degree of binding of DPDPE to serum proteins. Results. The majority of the administered dose (~80%) was recovered from bile as intact peptide. DPDPE disposition was best described by a two-compartment model with Michaelis-Menten elimination (K_m: 37.5 ± 11 g/ml; V_max: 1143 ± 368 g/min/kg) from the central compartment into bile, suggestive of an active hepatic transport system. DPDPE was associated with a distributional space of 486 ± 62 ml/kg. In vitro incubation of DPDPE with whole blood showed that ~65% of the peptide was associated with erythrocytes. The difference between concentrations of DPDPE in erythrocytes and plasma was statistically significant (29.2 ± 4.9 vs. 18.1 ± 3.1 g/ml, p < 0.05), but not between whole blood and plasma (21.3 ± 2.8 vs. 18.1 ± 3.1 g/ml, p > 0.05). Concentration-independent binding of DPDPE to serum proteins was evidenced between 10 and 100 (g/ml, with an unbound fraction of 0.517 ± 0.182. Conclusions. DPDPE undergoes extensive biliary excretion after i.v administration in rats. The apparent nonlinearity in the biliary excretion of DPDPE revealed by the pharmacokinetic modeling strongly suggests the existence of an active transport system(s) in hepatocytes which may mediate the rapid disappearance of DPDPE from the systemic circulation.     

Inhibition of Ca2+ channel current by μ- and κ-opioid receptors coexpressed in Xenopus oocytes: desensitization dependence on Ca2+ channel α1 subunits

1. Desensitization of μ- and κ-opioid receptor-mediated inhibition of voltage-dependent Ca²⁺ channels was studied in a Xenopus oocyte translation system.
2. In the oocytes coexpressing κ-opioid receptors with N- or Q-type Ca²⁺ channel α₁ and β subunits, the κ-agonist, U50488H, inhibited both neuronal Ca²⁺ channel current responses in a pertussis toxin-sensitive manner and the inhibition was reduced by prolonged agonist exposure.
3. More than 10 min was required to halve the inhibition of Q-type channels by the κ-agonist. However, the half-life for the inhibition of N-type channels was only 6±1 min. In addition, in the oocytes coexpressing μ-opioid receptors with N-type or Q-type channels, the uncoupling rate of the μ-receptor-mediated inhibition of N-channels was also faster than that of Q-type channels.
4. In the oocytes coexpressing both μ- and κ-receptors with N-type channels, stimulation of either receptor resulted in a cross-desensitization of the subsequent response to the other agonist. Treatment of oocytes with either H-8 (100 μM), staurosporine (400 nM), okadaic acid (200 nM), phorbol myristate acetate (5 nM) or forskolin (50 μM) plus phosphodiesterase inhibitor did not affect either the desensitization or the agonist-evoked inhibition of Ca²⁺ channels.
5. These results suggest that the rate of rapid desensitization is dependent on the α₁ subtype of the neuronal Ca²⁺ channel, and that a common phosphorylation-independent mechanism underlies the heterologous desensitization between opioid receptor subtypes.

     

Respiratory responses of elite oarsmen,former oarsmen,and highly trained non-rowers during rowing,cycling and running

The position of the body and use of the respiratory muscles in the act of rowing may limit ventilation and thereby reduce maximal aerobic power relative to that achieved in cycling or running, in spite of the greater muscle mass involved in rowing. This hypothesis was investigated for three groups of male subjects: nine elite senior oarsmen, eight former senior oarsmen and eight highly trained athletes unskilled in rowing. The subjects performed graded exercise to maximal effort on a rowing ergometer, cycle ergometer and treadmill while respiratory minute volume and oxygen consumption were monitored continuously. The VE at a given during intense submaximal exercise (greater than 75% of maximal ) was not significantly lower in rowing compared with that in cycling and treadmill running for any group, which would suggest that submaximal rowing does not restrict ventilation. At maximal effort, and for rowing were less than those for the other types of exercise in all the groups, although the differences were not statistically significant in the elite oarsmen. These data are consistent with a ventilatory limitation to maximal performance in rowing that may have been partly overcome by training in the elite oarsmen. Alternatively, a lower maximal VE in rowing might have been an effect rather than a cause of a lower maximal if maximal was limited by the lower rate of muscle activation in rowing.     

κ阿片受体介导100 Hz电针对吗啡戒断大鼠心动过速的缓解作用

目的：研究１００Ｈｚ电针缓解吗啡戒断大鼠心动过速的受体机制。方法：在吗啡戒断１８～２４ｈ的大鼠模型上,腹腔注射阿片受体拮抗剂纳络酮（ｎａｌｏｘｏｎｅ,ＮＸ）或侧脑室注射κ阿片受体拮抗剂ｎｏｒｂｉｎａｌｔｏｒｐｈｉｍｉｎｅ（ｎｏｒＢＮＩ）,给予１００Ｈｚ电针刺激,记录吗啡戒断大鼠清醒状态下的心率和血压。结果：１００Ｈｚ电针的作用可被腹腔注射ＮＸ１ｍｇ·ｋｇ－１完全翻转、被侧脑室注射ＮｏｒＢＮＩ１２ｎｍｏｌ完全阻断。结论：１００Ｈｚ电针抑制吗啡戒断大鼠心动过速的作用主要是通过中枢κ阿片受体介导的。     

The relationship between waist-to-hip ratio and occupational status and life-style factors among middle-aged male and female Japanese workers.

As a marker of body fat distribution and therefore level of obesity, the waist-to-hip ratio (W:H) is a good indicator of coronary heart disease risk status. The present study investigated the association between occupational status and life-style factors, and W:H of middle-aged Japanese male (n = 2,550) and female (n = 1,283) workers in a metal-products factory. A higher W:H was observed in the management level males as compared with the other male workers and we suggest this was promoted by the sedentary aspect of their work, as well as their higher levels of alcohol consumption and lower levels of leisure-time physical activity. In contrast, a higher W:H was recorded in female labourers, whose work was typically less sedentary as compared with female managers. Life-style factors included in the study were not related to this observation. We conclude that other unmeasured psychosocial factors may be important in promoting higher W:H in female labourers.     

麻醉性镇痛药使用及依赖性发生的调查

本文调查分析１所大型综合性医院１９８９－１９９４年麻醉性镇痛药使用情况,平均年消耗量为２９６４５±ｓ５５９１ＤＤＤｓ。年开支金额逐年增加,１９９４年为１９９０年的４４０％。内科用量占全院的５５．３％,二氢埃托啡片１９９１年猛增至１０万片以上,卫生部下达文件后下降。门诊麻醉镇痛药用量占４．９％,其处方量占总处方量的０．３５％。主要使用单位是急诊科,占７０．２％。男女患者比为２．４：１;２６－４５ａａ组占４５．６％。药物利用指数０．２９－０．７０,使用不当者主要是二氢埃托啡,发现２人发生依赖性。４３名癌痛患者很少按“三阶梯止痛疗法”给药。根据存在的问题,本文提出相应的建议。