Use of di-isopropyl phenol as main agent for short procedures

The use of di-isopropyl phenol (Diprivan) for induction of anaesthesia was assessed in doses ranging from 1 to 3 mg kg-1. With less than 1.75mg kg-1 not all patients were anaesthetized; 2.0 mg kg-1 appeared to be a satisfactory induction dose. Involuntary muscle movement, cough and hiccup at induction were rare with any dose studied. However, the frequency of hypotension and respiratory depression were related to the dose given. Pain on injection was uncommon when the drug was given into an antecubital vein, but occurred in 39% of patients when injected to the back of the hand or wrist. Recovery was rapid, and characterized by lack of emetic sequelae. Di-isopropyl phenol 1.5 - 2.0 mg kg-1 given rapidly during reactive hyperaemia can produce anaesthesia in one arm-brain circulation time. A reaction involving flush, hypotension, cough, laryngospasm and bronchospasm occurred in one patient receiving 2.5 mg kg-1 given over 20 s.

Pharmacokinetic evaluation of ICI 35 868 in man. Single induction doses with different rates of injection

Blood concentrations of ICI 35 868 have been measured in patients following a single bolus dose of 2 mg kg-1. Three different rates of injection of the anaesthetic agent (3-5s, 20s and 40 or 50s) were examined. Pharmacokinetic indices, derived from blood concentrations of ICI 35 868, were independent of the speed of injection. The blood profiles could be described by a two-compartment open model with a mean alpha-phase half-life of 2.5 min and a mean beta-phase half-life of 54.5 min. The mean total body clearance was 3454 ml min-1. Similar data were obtained from a 4-mg kg-1 dose. The mean recovery time (4.4 min) and concentration of ICI 35 868 at awakening (1.05 micrograms ml-1) were also independent of the rate of injection. Using the derived pharmacokinetic model, predictions of drug concentrations have been made for repeated bolus doses, or infusions, of ICI 35 868.

Neurological toxicity of the subarachnoid infusion of bupivacaine, lignocaine or 2-chloroprocaine in the rat

Neurotoxicity after subarachnoid infusion of bupivacaine, lignocaine and 2-chloroprocaine was studied in a chronic rat model. Hartmann's solution 100 microliter h-1 was infused as a control, and 0.5% bupivacaine, 1.5% lignocaine and 2.0% 2-chloroprocaine were infused at 100 microliter h-1 for 3, 6 or 24 h, to five rats in each group. No residual paralysis occurred in the control group, but 27 of 45 rats (60%) which received an infusion of local anaesthetic had residual paralysis lasting until sacrifice at 7 days. The incidence of paralysis was dependent on the duration of exposure to the local anaesthetic, but there were no significant differences in incidence between any of the local anaesthetics tested. Abnormal histology, in the form of neuronal vacuolation, was not a sensitive index, being present in control rats, but more intense in those receiving lignocaine and 2-chloroprocaine than in those given bupivacaine; no correlation with clinical findings could be established. The neurotoxic effects of each local anaesthetic tested as a continuous intrathecal infusion were dose related in the rat, which may be a useful model for screening other local anaesthetics.

Chronic cannulation of the intradural or extradural space in the rat

An animal preparation has been developed to test therapeutic agents in the extradural and intradural spaces. Under anaesthesia a hole was drilled in the penultimate lumbar vertebra of male Wistar rats and the appropriate space cannulated. The catheter was tunnelled subcutaneously to emerge at the neck. There was no spinal cord or meningeal reaction after 1 month. Catheters remained patent for 3 months. The method of cannulation allowed free rostral spread of drugs. Using plain 2% lignocaine, paralysis and anesthesia of the hind limbs required an intradural volume of 32 +/- 3 mulitre: the required volume on extradural injection was 46 +/- 2 mulitre (P less than 0.01). Paralysis of all limbs required an intradural volume of 115 +/- 12 mulitre. Respiratory arrest and death required a mean intradural volume of 179 +/- 15 mulitre.

Comparison of the effect of diisopropyl phenol (ICI 35, 868) and thiopentone on response to somatic pain

The response to somatic pain with sub-hypnotic doses of ICI 35, 868 (diisopropyl phenol in cremophor) and thiopentone was compared using tibial pressure algesimetry. Studies were also carried out following recovery from larger doses of both drugs. The patients underwent gynaecological procedures using only one of the two i.v. agents and nitrous oxide in oxygen. The studies confirmed the known antanalgesic action of thiopentone and demonstrated that diisopropyl phenol has an analgesic action which is an attractive feature in an i.v. anaesthetic agent.

Neurotoxicity after spinal anaesthesia induced by serial intrathecal injections of magnesium sulphate. An experimental study in a rat model

We have previously demonstrated in a rat model that the lumbar intrathecal injection of 0.02 ml 6.3% magnesium sulphate, a concentration iso-osmolar with rat plasma, produces a state of spinal anaesthesia and general sedation which reversed completely after 6 h, without evidence of neurotoxicity, immediately or during the week thereafter. Using the same model and five groups of six animals in each, we administered the same volume and concentration of magnesium sulphate and compared its clinical effects with those of 0.02 ml 12.6% magnesium sulphate, 0.02 ml 2% lignocaine and 0.02 ml 0.9% sodium chloride solution, given as a series of 15 injections on alternate days for a period of 1 month. The animals were then killed and their spinal cords and meninges examined histologically. No significant differences were noted in the times of onset, durations of sensory and motor blockade and the times to full recovery throughout the entire period of 1 month's observation in the animals receiving intrathecal 6.3% magnesium sulphate. In the group receiving 12.6% magnesium sulphate, the time of onset of sensory and motor blockade was shorter and the duration of both parameters was significantly longer than in the former group. Full clinical recovery and resumption of normal eating and drinking took place in both groups throughout the entire series of 15 successive intrathecal injections. Identical, mild, uniform histopathological changes in the spinal cord were seen in all the five groups, including the group in which only the intrathecal catheter was implanted. The complete recovery and benign consequences of repeated intrathecal injections of iso-osmolar magnesium sulphate in a rat model indicate a lack of neurotoxicity and provide an impetus for further trials in larger animal species, before initial clinical trials of this substance, given intrathecally, in humans.

Are elevated liver enzymes and bilirubin levels significant after laparoscopic cholecystectomy in the absence of bile duct injury?

OBJECTIVE

Increased aspartate aminotransferase (AST), alanine aminotransferase (ALT), and bilirubin levels were noted incidentally after a laparoscopic cholecystectomy. The percentage in which such elevation occurs and its clinical significance in the absence of bile duct injury were investigated.

SUMMARY BACKGROUND DATA

Bile duct injury is the most feared complication of laparoscopic cholecystectomy. Some laboratory tests may be indicative of this complication, such as increases in liver enzyme (AST, ALT, and alkaline phosphatase [ALP]) and bilirubin. These parameters have not been investigated in patients who had laparoscopic cholecystectomy and in whom no damage to the bile duct was noted.

METHODS

Sixty-seven patients with normal results of preoperative liver function test were entered into the study. Blood was collected 24 hours after laparoscopic cholecystectomy, and AST, ALT, ALP, and bilirubin levels were measured.

RESULTS

A mean 1.8-fold increase in AST occurred in 73% of patients; 82% showed a 2.2-fold increase in ALT. A statistically nonsignificant increase was noted in 53% of patients (ALP remained within normal limits), and in 14% of patients bilirubin levels were increased (they were primarily of the unconjugated type).

CONCLUSIONS

In many patients a significant increase in AST and ALT levels occurred after laparoscopic cholecystectomy, but they returned to normal values within 72 hours. The cause of this is unclear, and these elevations appear to have no clinical significance.

Physostigmine antagonizes morphine-induced respiratory depression in human subjects

The effect of physostigmine on the respiratory depression induced by morphine was studied in human subjects who received morphine as part of their preanesthetic medication. After pretreatment with droperidol (2.5-5 mg, iv) to prevent nausea, the change in minute ventilation was measured in 16 patients in response to increasing concentrations of inspired CO2 (CO2-response curve) by the rebreathing method. This was repeated 30 min after morphine (0.166 mg/kg, iv) in nine subjects and in seven controls who did not receive morphine and again 5-10 min after physostigmine (13-33 micrograms/kg, iv) in all subjects. All subjects were given N-butylhyoscine hydrobromide (5 mg, iv) to antagonize any peripheral cholinergic effects of physostigmine. Morphine decreased the mean slope of the CO2-response curve from 1.78 +/- 0.18 to 1.12 +/- 0.14 1 X min-1 X mmHg-1 (P less than 0.01) and increased the alveolar PCO2 for a fixed minute ventilation (position of curve) from 45.0 +/- 1.3 to 51.9 +/- 1.5 mmHg (P less than 0.001). Physostigmine restored the mean slope after morphine to control value, i.e., 1.79 +/- 0.231 X min-1 X mmHg-1, and position to 46.2 +/- 1.2 mmHg (P less than 0.001). Physostigmine did not increase the slope or alter the position of the CO2-response curves of subjects given droperidol alone. The authors conclude that physostigmine can reverse the respiratory depressant effect of morphine and restore the sensitivity of the respiratory center of CO2, presumably by raising acetylcholine levels in the brain after these have been reduced by morphine.

Spinal anaesthesia with midazolam in the rat

PURPOSE

This study examined in an animal model whether intrathecal midazolam, alone or with fentanyl, can achieve anaesthesia sufficient for laparotomy, comparable to lidocaine. Effects on consciousness and whether anaesthesia was segmental were also examined. The haemodynamic and respiratory changes were compared with those of intrathecal lidocaine or intrathecal fentanyl alone.

METHODS

Sixty Wistar strain rats, with nylon catheters chronically implanted in the lumbar subarachnoid theca, were divided into six groups. Group 1 (n = 12) received 75 microL intrathecal lidocaine 2%. Group 2 (n = 12) received 75 microL intrathecal midazolam 0.1%, Group 3 (n = 12) received intrathecal 37.5 microL midazolam 0.1%, plus 37.5 microL fentanyl 0.005%. Group 4 (n = 12) received intrathecal 50 microL fentanyl 0.005%. Group 5 (n = 6) received 75 microL midazolam 0.1% iv. Group 6 (n = 6) received halothane 0.6% in oxygen by inhalation.

RESULTS

Both groups that received intrathecal midazolam, alone or combined with fentanyl, developed effective segmental sensory and motor blockade of the hind limbs and abdominal wall, sufficient for a pain-free laparotomy procedure. Neither of these groups, unlike the group that received intrathecal lidocaine, developed a reduction in blood pressure or change in heart rate at the time of maximal sensory or motor blockade, nor were there changes in the arterial blood gases or respiratory rate.

CONCLUSION

Midazolam, when injected intrathecally, produces reversible, segmental, spinally mediated antinociception, sufficient to provide balanced anaesthesia for abdominal surgery.

Physostigmine antagonizes morphine-induced respiratory depression but not analgesia in dogs and rabbits

The ability of physostigmine to antagonize the respiratory depressant effect of morphine was studied in conscious rabbits and ketamine-anaesthetized dogs pretreated with atropine methyl nitrate. Morphine 4 mg kg-1 increased PaCO2 in the rabbit from 3.43 +/- 0.16 to 4.95 +/- 0.28 kPa, decreased arterial pH from 7.45 +/- 0.01 to 7.31 +/- 0.01 and decreased respiratory frequency by 36%. Physostigmine 0.1 mg kg-1 reduced PaCO2 to control values within 10 min and significantly increased arterial pH and respiratory frequency. There was no antagonism of the analgesic effect of morphine. Neostigmine 0.1 mg kg-1 did not reverse the respiratory depressant effect of morphine. In dogs anaesthetized with ketamine, morphine 15 mg kg-1 caused loss of consciousness and marked analgesia, decreased the respiratory frequency by 47%, and increased PaCO2 by 47%. Physostigmine 0.1 mg kg-1 antagonized the effect of morphine on respiration and restored consciousness in the dogs, but did not impair analgesia. It is concluded that physostigmine reverses morphine-induced respiratory depression by prolonging the effect of acetylcholine released from brain-stem neurones. The possibility should be considered of replacing opiate antagonists by physostigmine to reverse postoperative respiratory depression and drowsiness induced by opiates.

High-output left ventricular failure after dextran use in an operative hysteroscopy

High-output left ventricular failure occurred in a patient after a difficult case of hysteroscopic lysis of adhesions using dextran as a distension medium. The excessive dissection in the uterine wall, the long duration of the operation, and the large volumes of dextran probably caused intravasation of dextran into the systemic circulation inducing a significant shift of fluids from the third space. This was possibly assisted by the large volume of fluids given intravenously in a 45-kg patient initiating the reported sequence of events.

A model for the catabolism of rhizopine in Rhizobium leguminosarum involves a ferredoxin oxygenase complex and the inositol degradative pathway

Rhizopines are nodule-specific compounds that confer an intraspecies competitive nodulation advantage to strains that can catabolize them. The rhizopine (3-O-methyl-scyllo-inosamine, 3-O-MSI) catabolic moc gene cluster mocCABRDE(F) in Rhizobium leguminosarum bv. viciae strain 1a is located on the Sym plasmid. MocCABR are homologous to the mocCABR gene products from Sinorhizobium meliloti. MocD and MocE contain motifs corresponding to a TOL-like oxygenase and a [2Fe-2S] Rieske-like ferredoxin, respectively. The mocF gene encodes a ferredoxin reductase that would complete the oxygenase system, but is not essential for rhizopine catabolism. We propose a rhizopine catabolic model whereby MocB transports rhizopine into the cell and MocDE and MocF (or a similar protein elsewhere in the genome), under the regulation of MocR, act in concert to form a ferredoxin oxygenase system that demethylates 3-O-MSI to form scyllo-inosamine (SI). MocA, an NAD(H)-dependent dehydrogenase, and MocC continue the catabolic process. Compounds formed then enter the inositol catabolic pathway.

Application of the use of high-throughput technologies to the determination of protein structures of bacterial and viral pathogens

The Structural Proteomics In Europe (SPINE) programme is aimed at the development and implementation of high-throughput technologies for the efficient structure determination of proteins of biomedical importance, such as those of bacterial and viral pathogens linked to human health. Despite the challenging nature of some of these targets, 175 novel pathogen protein structures (approximately 220 including complexes) have been determined to date. Here the impact of several technologies on the structural determination of proteins from human pathogens is illustrated with selected examples, including the parallel expression of multiple constructs, the use of standardized refolding protocols and optimized crystallization screens.

Lateral recumbent head-down posture for epidural catheter insertion reduces intravascular injection

PURPOSE

The unintentional and unrecognized cannulation of an extradural vein is a potentially serious complication of an epidural anesthetic. The present study was undertaken to assess the incidence of blood vessel puncture related to epidural catheterization performed in three different body positions.

METHODS

The study was conducted in 900 (three groups of 300) obstetric patients undergoing continuous epidural analgesia during their labour and who were randomly allocated to three groups. Epidural catheterization was performed with patients in the sitting, lateral recumbent horizontal, or lateral recumbent head-down position.

RESULTS

There was a lower incidence of vessel cannulation when this procedure was performed in the lateral recumbent head-down position (2%) than in the lateral recumbent horizontal (6%) and in the sitting position (10.7%).

CONCLUSION

Adoption of the lateral recumbent head-down position for the performance of lumbar epidural blockade, in labour at term, reduces the incidence of lumbar epidural venous puncture.

Primary malignant melanoma in the parotid gland

Reports of primary malignant melanoma arising from the parotid salivary gland are extremely rare and, to date, have been sporadic. We report a pertinent case, and tabulate and correlate the clinical findings of the 13 cases reported thus far in the literature. The most common symptom is a progressively enlarging, asymptomatic, firm, and fixed mass. Total excision has been the established treatment of choice. The contribution of radiotherapy, chemotherapy, and immunotherapy remains unclear, and it is not possible at present to predict the outcome of treatment in individual patients. Although rare, primary malignant melanoma should be considered in the differential diagnosis of parotid tumors. The clinical significance of establishing the diagnosis of primary malignant melanoma of the parotid gland is emphasized.

An investigation of the possible neurotoxic effects of intrathecal midazolam combined with fentanyl in the rat

In previous work, midazolam was injected intrathecally and produced reversible, segmental, spinally mediated anti-nociception sufficient for abdominal surgery in a rat model. The neurotoxic effect of midazolam, alone or combined with fentanyl, injected intrathecally repeatedly on 15 occasions over a period of 1 month, was studied in the same model. We sought to establish whether this would produce neurological damage or neurotoxic injury. Histopathological examination of the excised spinal cord and paraspinal tissues was carried out. Thirty Wistar strain rats with nylon catheters chronically implanted in the lumbar subarachnoid space were divided into five groups: group 1 (n = 6) received 40 microL of midazolam 0.1%; group 2 (n = 6) received 40 microL of fentanyl 0.005%; group 3 (n = 6) received 20 microL of midazolam 0.1% plus 20 microL of fentanyl 0.005%; group 4 (n = 6) received 40 microL of lignocaine 2%; group 5 (n = 6) received 40 microL of phenol in water. All substances were injected through the implanted catheters. The neurological recovery of all the animals in the four groups that received intrathecal midazolam alone, fentanyl alone, midazolam plus fentanyl and lignocaine alone was similar and complete. There were no significant differences in the histological changes in the neural tissues of these groups, despite repeated application of the test substances. Group 5 demonstrated the typical neurolytic lesions of phenol when injected intentionally into the subarachnoid space.

Probiotic feeding affects T cell populations in blood and lymphoid organs in chickens

This study was performed to evaluate the effects of Lactobacillus acidophilus bacteria as a probiotic on chicken T cell subset populations in peripheral blood and lymphoid tissues. Thirty chickens were divided into three groups and fed sterilised cow milk, a mixture of milk and L. acidophilus (probiotic), or neither, as the control group. Chickens were euthanised after 14 and 21 days, and whole blood and ileal, bursal, and caecal tonsillar tissues were collected. The populations of T cell subsets, including CD4⁺, CD8⁺, and TCR1⁺ cells, were evaluated by immunohistochemistry and flow cytometry. After 21 days of treatment the percentage of blood CD4⁺, CD8⁺, and TCR1⁺ cells was significantly higher in the probiotic-fed group than in the control group. After 14 days of treatment, a significantly greater number of CD4⁺ T cells were found in the ileum of probiotic-fed chickens than in chickens from the other two groups. This difference was even greater after 21 days. In addition, after 21 days, a significantly greater number of TCR1⁺ cells were found in the caecal tonsils of milk-fed chickens than in chickens from the control group. The findings indicate that probiotics may alter the distribution of T cells in the blood and lymphoid tissues in young chickens; however, transient changes in lymphoid tissues indicate that probiotics likely do not permanently affect mucosal immunity.

Enumeration of bacteriophages in water by different laboratories of the European Union in two interlaboratory comparison studies

As part of a European project on bacteriophages in bathing waters two interlaboratory comparison studies were carried out (May 1997 and March 1998). During these studies phage reference materials as well as naturally polluted standard samples were analysed in 16 European laboratories. Three groups of bacteriophages were tested using standardised methods: somatic coliphages, F-specific RNA-phages and phages of Bacteroides fragilis. Many of the participating laboratories applied one or more of the phage methods for the first time, after a one-week training session in a central laboratory. Nevertheless, the values of repeatability (r=1.35-1.38 calculated on log(10)-scale) and reproducibility (R=1.52-2.04 calculated on log(10)-scale) when analysing phage reference materials were close to the theoretical optimum for a Poisson distribution. When analysing the naturally polluted samples more variation in results within and between laboratories was found (r=1.63-2.34; R=3.10-5.72), in comparison with the results obtained with the pure phage reference materials.

Effect of preanaesthetic medication on anaesthesia with ICI 35, 868

The effect of three commonly used premedicants and a control on anaesthesia with ICI 35, 868 is described. Two randomized studies were performed--one a group study of induction characteristics at 2 mg kg-1 and the other a detailed study in patients undergoing minor gynaecological surgery with an induction dose of 1.5 mg kg-1 and maintenance with incremental doses plus 66% nitrous oxide in oxygen. Premedication had little effect on the already good induction characteristics. Only heavy opiate premedication produced reliable induction at 1.5 mg kg-1, but with an increase in side-effects. Diazepam appears to be the premedicant of choice, although the overall frequency of pain on injection has not been affected by premedication.

Nitric Oxide-Releasing Bacterial Cellulose/Chitosan Crosslinked Hydrogels for the Treatment of Polymicrobial Wound Infections

Polymicrobial wound infections are a major cause of infectious disease-related morbidity and mortality worldwide. In this study, we prepared a nitric oxide (NO)-releasing oxidized bacterial cellulose/chitosan (BCTO/CHI) crosslinked hydrogel to effectively treat polymicrobial wound infections. Linear polyethyleneimine diazeniumdiolate (PEI/NO) was used as the NO donor. The aldehyde group of BCTO and the amine of CHI were used as crosslinked hydrogel-based materials; their high NO loading capacity and antibacterial activity on the treatment of polymicrobial-infected wounds were investigated. The blank and NO-loaded crosslinked hydrogels, namely BCTO-CHI and BCTO-CHI-PEI/NO, were characterized according to their morphologies, chemical properties, and drug loading. BCTO-CHI-PEI/NO exhibited sustained drug release over four days. The high NO loading of BCTO-CHI-PEI/NO enhanced the bactericidal efficacy against multiple bacteria compared with BCTO-CHI. Furthermore, compared with blank hydrogels, BCTO-CHI-PEI/NO has a favorable rheological property due to the addition of a polymer-based NO donor. Moreover, BCTO-CHI-PEI/NO significantly accelerated wound healing and re-epithelialization in a mouse model of polymicrobial-infected wounds. We also found that both crosslinked hydrogels were nontoxic to healthy mammalian fibroblast cells. Therefore, our data suggest that the BCTO-CHI-PEI/NO developed in this study improves the efficacy of NO in the treatment of polymicrobial wound infections.

Fluid preload before spinal anaesthesia in Caesarean section

BACKGROUND AND OBJECTIVE

We evaluated the effect of two different preload solutions: (i) Ringer's lactate (compound sodium lactate intravenous infusion BP) and (ii) 0.9% sodium chloride solution on the neonatal acid-base status of the newborn infants. The two standard regimens were compared to detect a possible difference.

METHODS

A 2 L crystalloid fluid bolus was administered immediately before spinal anaesthesia for elective Caesarean section in two groups of 20 healthy parturients, while rigorously maintaining maternal normotension.

RESULTS

No significant differences in the Apgar scores at 1 and 5 min, or infant well-being were demonstrated in either of the two groups. The data show that umbilical artery PCO2 is lower in the Ringer's lactate group and that pH is insignificantly higher by 0.03.

CONCLUSIONS

The choice of Ringer's lactate or saline for fluid preload does not have any effect on neonatal well-being.

The role of meatal disinfection in preventing catheter-related bacteriuria in an intensive care unit: a pilot study in Turkey

The purpose of this study was to investigate the efficacy of antiseptics meatal care in preventing catheter-related urinary tract infections (UTIs) in patients with an indwelling urinary catheter in the intensive care unit of Osmangazi University Medical School. One hundred patients were divided into four groups (25 per group) and treated with once or twice daily application of chlorhexidine gluconate or povidone-iodine. A control group was also studied (N=30). Urine samples were taken weekly and cultures were evaluated quantitatively. Meatal swabs were obtained on the first, fifth, and 10th day and determinated semiquantitatively. UTI was defined as bacteriuria with 10(5)cfu/L. Cultures showing no growth or mixed growths were stated as negative for UTI. UTI developed in 16 patients on days two, three, four, five and seven (including control group). Dominant micro-organisms in the meatal area were found to be Candida species. In nine cases the causative agents of UTI were Candida species. It was therefore decided that the use of antiseptics to clean the periurethral area provides no benefit in decreasing the rate of bacteriuria.