EFFECT OF BILIARY EXCRETION ON KETAMINE ANAESTHESIA IN THE RAT

Ligation of the common bile duct in rats resulted in a significantprolongation of ketamine sleeping time and a significant increaseof plasma concentration of ketamine and its N-demethylated metabolite,when compared with sham-operated control animals. The treatedanimals also showed significant increases of plasma bilirubinand glutamate pyruvate transaminase. Cannulation of the commonbile duct in rats allowed collection of samples of bile whichshowed high concentrations of ketamine and its N-demethylatedmetabolite very shortly after i.p. injection of ketamine, theamount of ketamine alone accounting for 10% of the injecteddose after 2 h; including the metabolite up to 25% of the injecteddose could be accounted for. In view of this we would suggestthat ligation of the bile duct in rats produced a prolongationof ketamine anaesthesia by increasing plasma concentrationsthrough interference with a major excretory route for the drugand its main metabolite.     

THE EFFECT OF ANAESTHETIC AGENTS UPON CALF MUSCLE BLOOD FLOW IN THE ISCHAEMIC LIMB

The effect of anaesthesia using trichloroethylcne, halothane,and tubocurarine was studied on the calf blood flow before surgicalstimulation using venous occlusion plethysmography. There weretwenty-seven patients in the study divided into three groups,each group receiving one of the three anaesthetic agents. Allpatients had a history of intermittent claudication and weresubsequently shown to have abnormal aortograms. There was adecrease in calf blood flow in all three groups. Those patientsanaesthetized with halothane showed a considerably smaller decreasein flow compared to the other two groups. It is suggested thathalothane might be a more suitable agent for anaesthesia inpatients with lower limb ischaemia.     

EFFECTS OF INHALATION ANAESTHETIC AGENTS ON THE ELECTRICAL AND MECHANICAL ACTIVITY OF THE RAT DUODENUM

Sleep doses of halothane (4%), enflurane (2%) and diethyl ether(10%) were administered to fasting rats. Duodenal mechanicaland electrical activities were recorded using miniature extraluminalstrain gauges and silver/silver chloride bipolar electrodes.Halothane abolished, or significantly reduced, phase HI activityof the migrating myo-electnc complex whereas enflurane abolishedphase II activity but failed to reduce phase HI. Ether was associatedwith periods of intense activity throughout anaesthesia andthis activity persisted after recovery of consciousness. Allanaesthetic agents caused a marked slowing of the basic electricalrhythm.     

EFFECT OF CERTAIN ANAESTHETIC AGENTS ON THE ACTIVITY OF RAT HEPATIC {delta}-AMINOLAEVULINATE SYNTHASE

The activity of -aminolaevulinic acid synthase (E.C. 2.3.1.37 [EC] )(the rate-limiting enzyme for haem and porphyrin biosynthesis)has been measured in the rat liver after the repeated administrationof anaesthetic agents in vivo. The activity of the enzyme wasincreased by Althesin, chlordiazepoxide, enflurane, etomidate,lignocaine, methohexitone, methoyflurane, pentazocine and thiopentoneand decreased by procaine. No significant changes in activityoccurred after the administration of amethocaine, atropine,bupivacaine, diazepam, droperidol, halothane, ketamine, morphine,nitrous oxide, pethidine, phenoperidine, prilocaine and propanidid.It is suggested that those anaesthetic agents which inducedactivity of the enzyme should not be administered to patientswith an acute porphyria.     

THE EFFECT OF GENERAL ANAESTHETIC AGENTS ON NERVE CONDUCTION VELOCITIES

Nerve conduction velocity has been studied in the ulnar nerveof human subjects before and during anaesthesia. No significantchanges in velocity were observed following the administrationof thiopentone, nitrous oxide, oxygen and halothane in normalclinical quantities. A transient increase in nerve conductionvelocity was noted following the administration of paralyticdoses of gallamine triethiodide to subjects receiving nitrousoxide, oxygen and halothane anaesthesia in whom ventilationwas controlled.     

CYTOTOXICITY OF I.V. ANAESTHETIC AGENTS ON THE ISOLATED RAT HEPATOCYTE

The isolated rat hepatocyte model has been used to assess thehepatotoxicity of a number of i.v. anaesthetic induction agents.Ketamine, Althesin and CCI 12923 (minaxolone) all inhibitedgluconeogenesis and urea formation from alanine. There was alsoa decrease in the cell ATP concentration, and a dose-relatedincrease in leakage of LDH. Of these indices of cell toxicity,gluconeogenesis from alanine was found to be the most sensitive.Fifty per cent inhibition of gluconeogenesis for all three agentsoccurred in the range 150–300 µmol. The effectsof these agents on the isolated hepatocyte may be attributedto a primary impairment of mitochondrial function through achange in the ATP concentration. The plasma concentration ofanaesthetic agents measured during their clinical use is atleast one order of magnitude less than that required to cause50% inhibition of gluconeogenesis.     

阻塞性黄疸术前胆道外引流对肝细胞再生能力的影响

术前胆道外引注对阻塞性黄疸肝切除术后残肝细胞再生能力影响尚不清楚。本实验通过检测能反遇肝细胞再生能力的肝细胞核ＤＮＡ含量,有丝核分型计数（ＭＩ）和增殖细胞核抗原（ＰＣＮＡ）标记指数变化,对胆总管梗阻５天大鼠胆上引流,１、３、５天,然后观察７０％肝切除对残肝细胞再生能力的影响。实验结果表明：胆道外引流对肝细胞再生能力有抑制影响。     

EFFECTS OF THE EXTRADURAL ADMINISTRATION OF LOCAL ANAESTHETIC AGENTS AND MORPHINE ON THE URINARY EXCRETION OF CORTISOL, CATECHOLAMINES AND NITROGEN FOLLOWING ABDOMINAL SURGERY

Twenty patients undergoing major abdominal surgery were allocatedrandomly to receive either general anaesthesia with low-dosefentanyl plus intermittent systemic morphine for postoperativepain or the same general anaesthetic plus extradural analgesiaduring and following surgery (local anaesthetics from beforeskin incision until 24 h after skin incision plus extraduralmorphine 4 mg every 12 h from 3 h to 72 h after skin incision).Postoperative pain scores were lower (P < 0.05) in the groupreceiving extradural analgesia, but this regimen failed to preventthe increase in the urinary excretion of cortisol, adrenaline,noradrenaline and nitrogen both on separate days and on cumulativemeasurements over 4 days. Pain scores did not correlate to urinaryexcretion of the various endocrine-metabolic indices eitheron separate days or over the cumulative 4-day period. It isconcluded that the relief of pain per se has no major influenceon the catabolic response to abdominal surgery.     

EFFECT OF NALOXONE ON THE LOSS OF CONSCIOUSNESS INDUCED BY I.V. ANAESTHETIC AGENTS IN MAN

The effect of a specific opioid antagonist, naloxone, was studiedin two comparable groups of patients who received i.v. the doseof an anaesthetic agent required to produce loss of consciousnessin 50% of subjects. The first group received naloxone 0.006mg kg^–1 5 min before induction of anaesthesia; the secondgroup received a similar volume of saline solution. Thiopentone,Althesin, diazepam, ketamine and propanidid were studied. Thedifferences in percentage of unconscious patients between thenaloxone-treated group and the control group were statisticallysignificant for diazepam, ketamine and propanidid. Naloxonedid not modify the induction of anaesthesia with thiopentoneor Althesin     

CHANGES IN LIVER BLOOD FLOW WITH DEVELOPMENT OF BILIARY OBSTRUCTION IN THE RAT1

As well as causing retention of biliary secretory products, bile duct obstruction is associated with other hepatic and systemic effects which are poorly understood. These latter changes contribute to the increased morbidity and mortality associated with surgery for biliary obstruction. This study examines the changes in liver blood flow occurring after common bile duct (CBD) ligation in the belief that relative hepatic ischaemia may contribute to dysfunction. A new method for measuring liver blood flow (LBF) based on the clearance of ¹³³Xe from the liver following injection into the portal vein is described. With this new development, serial measurements of LBF can be performed in the conscious, unfasted rat. With the development of jaundice, a highly significant reduction in LBF is seen which is first evident 36 hours after CBD ligation. By the third day after ligation, LBF is only 54% of the control value. No fall in LBF is seen in rats subjected to sham ligation. The mechanism for the reduction in LBF is uncertain, but the delayed onset makes any reflex autonomic reaction unlikely.     

熊去氧胆酸对胆固醇结石患者胆囊胆汁脂类浓度成核时间及胆囊排空能力的影响

作者测定了３８例胆囊胆固醇结石患者服用小量熊去氧胆酸（４００ｍｇ／ｄ）后的胆囊胆汁脂类浓度、成核时间及胆囊排空能力的变化。结果发现：小剂量熊去氧胆酸可降低胆囊胆汁胆固醇饱和指数．延长成核时间，但对胆囊排空能力无影响。认为熊去氧胆酸可通过降低胆固醇饱和指数，延长胆固醇晶体成核过程而对胆囊结石起预防作用。     

THE EFFECT OF FOUR VOLATILE ANAESTHETIC AGENTS ON THE IMPULSE ACTIVITY OF TWO TYPES OF PULMONARY RECEPTOR

The effect of halothane, ether, chloroform and trichloroethyleneon the impulse discharge of two types of pulmonary receptorhas been investigated in cats and dogs under chloralose or barbiturateanaesthesia. Afferent impulses were recorded from pulmonarystretch fibres and also from slowly-conducting vagal fibreswhose pulmonary endings were stimulated by hyperinflation (high-thresholdinflation receptors). Ventilating the lungs with low concentrationsof each agent (e.g. 1–3 per cent halothane) caused sensitizationof the pulmonary stretch receptors but had no effect on thehigh-threshold endings. With high concentrations (e.g. 5–20per cent halothane), pulmonary stretch receptors showed an initialsensitization followed by a reduction or abolition of activity,while the high-threshold receptors showed a marked increasein impulse activity during inflation. The possibility is discussedthat the high-threshold inflation receptors may be involvedin some of the reflex effects that have been observed duringsurgical anaesthesia with high concentrations of halothane.     

胆道探查术中胆道下端损伤的防治

目的预防下端胆管探查术中医源性胆管损伤。方法总结自1992年5月~2004年5月期间1315例胆管下端探查术中12例胆管下端损伤的原因。结果胆道探查术中用金属探条极易损伤下端胆管。结论胆道探查术中用规范操作是防止损伤的有效措施,及时发现损伤并对损伤部位进行合理有效的处理是提高病人预后的最佳方法。     

EFFECT OF VENTILATION AND CARDIAC OUTPUT ON THE UPTAKE OF ANAESTHETIC AGENTS FROM DIFFERENT BREATHING SYSTEMS: A THEORETICAL STUDY

We have investigated the influences of ventilation and cardiacoutput on uptake of anaesthetic with different breathing systems,by analysis of simple equations and by computer simulation.Increases in cardiac output and ventilation increased uptakefrom those systems which provided a constant inspired concentration,but not from completely closed systems with the vaporizer outof the circle (VOC), or when using the technique described byLowe and Ernst. When the vaporizer was inside the circle, uptakeincreased with ventilation but not with cardiac output. Withservo control of endtidal concentration, uptake increased withcardiac output but not with ventilation. When the fresh gasflow to VOC systems was increased from basal, independence ofuptake from ventilation was well maintained until fresh gasflow approached alveolar ventilation, but the independence ofuptake from cardiac output was lost much sooner.     

THE PRODUCTION OF LARYNGOSPASM IN THE CAT BY VOLATILE ANAESTHETIC AGENTS

Laryngospasm and apnoea or alterations in the rhythm of respirationhave been produced in decerebrate preparations of cats and incats anaesthetized with chloralose during the start of inhalationof volatile anaesthetic agents. Ether, halothane and methoxyfluraneall produced these effects when they were placed in contactwith the larynx. The responses to ether occurred more rapidlythan those to halothane, which in turn had a faster effect thanmethoxyflurane. In the concentrations used, ether vapour (10–20per cent) and halothane vapour (6–8 per cent) stimulatedlaryngospasm and apnoea when administered through either thenasopharynx and larynx, the mid-cervical trachea or the distaltrachea and lungs. Methoxyflurane (2.9 per cent) did not havethese actions in the trachea and lungs. The responses obtainedwere detected in the absence of the continuity of the olfactorypathway, due to decerebration in which no loss of trigeminalafferents was occasioned. The importance of nasal, laryngeal,pharyngeal, tracheal and pulmonary stimulation in the productionof laryngospasm and apnoea caused by inhaling; anaesthetic vapourshas been demonstrated. Present address: Veterinary Clinical Centre, University of Melbourne,Werribee, Victoria, 3030, Australia.     

EFFECT OF A EUTECTIC MIXTURE OF LOCAL ANAESTHETIC AGENTS (EMLA) ON TOURNIQUET PAIN IN VOLUNTEERS

We studied the effects of EMLA on tourniquet pain in 10 healthymale volunteers. The tourniquet inflation time which was toleratedwas significantly longer with EMLA (46.4 (SEM 3.5) min) comparedwith placebo (37.5 (2.7) min) (P < 0.05). Linear analoguepain scores increased in both groups over the study period,but were significantly less in the EMLA group at 40 min (P <0.05). We conclude that tourniquet pain has a significant cutaneouscomponent.     

EFFECT OF UNDERNUTRITION ON UPTAKE AND DISTRIBUTION OF IV. ANAESTHETIC AGENTS: A Study in Mice

The uptake and distribution of two i.v. anaesthetic agents,thiopentone and Althesin, were studied in mice with normal andsubnormal nutritional states. The results show that, followingthe administration of thiopentone, the induction time was significantlyshorter, and that the sleeping time was significantly longerfollowing the administration of Althesin and thiopentone inmice that have low net protein utilization, and decreased totaland dry body mass. The increase in the sleeping time in theseundernourished mice was 2.2 times greater for Althesin and 4.0times greater for thiopentone when compared with well-nourishedmice.     

胆道梗阻时胆囊及胆管胆汁流动特性比较

采用大胆总管梗阻模型，观察胆道梗阻后不同时期胆囊胆汁及胆管胆汁流动特性的变化。结果：正常犬胆囊胆汁及胆管胆汁的流动符合Ｃａｓｓｏｎ流动；胆道梗阻后，随胆道梗阻时间延长，胆囊及胆管胆汁均保持Ｃａｓｓｏｎ流动，胆管胆汁的屈服值及高、低切变率下表观粘度变化均类似于胆囊胆汁。     

EFFECT OF SOME I.V. ANAESTHETIC AGENTS ON CANINE GASTROINTESTINAL MOTILITY

Thiopentone 20 mg kg^–1, ketamine 8 mg kg^–1 and minaxolone2 mg kg^–1 were administered to fasting greyhound dogs.Mechanical and electrical activities from stomach, duodenum,jejunum and ileum were recorded using strain gauge force transducersand implanted bipolar electrodes. Thiopentone and minaxolonecaused intense activity in the duodenum and jejunum (phase Iand phase II of the interdigestive cycle), but not the stomachor ileum. The activity following injection of thiopentone orminaxolone was prevented by premedication with either atropine0.05 mg kg^–1 or pentolinium 0.2 mg kg^–1. Ketaminehad no influence on gastrointestinal activity or the responseto thiopentone or minaxolone. None of these drugs altered thebasal electrical rhythm of the intestine