Regulation of constitutive protein transit by phospholipase D in HT29-cl19A cells.

Phospholipase D (PLD) plays a central role in the control of vesicle budding and protein transit. We previously showed that in resting epithelial HT29-cl19A cells, PLD is implicated in the control of constitutive protein transit, from the trans-Golgi network to the plasma membrane, and that phorbol ester stimulation of protein transit is correlated with PLD activation (Auger, R., Robin, P., Camier, B., Vial, G., Rossignol, B., Tenu, J.-P., and Raymond, M.-N. (1999) J. Biol. Chem. 274, 28652-28659). In this paper we demonstrate that: 1) PLD is not implicated in the earliest phases of protein transit; 2) PLD controls apical but not basolateral protein transit; 3) HT29-cl19A cells express PLD1b and PLD2a mRNAs and proteins; 4) the expression of a catalytically inactive mutant of PLD2 (mPLD2-K758R) significantly inhibited apical constitutive protein transit whereas expression of a catalytically inactive mutant of PLD1 (hPLD1b-K898R) prevented increases in the rate of apical transit as triggered by phorbol esters; 5) PLD2 appears to be located in a perinuclear region containing the Golgi whereas PLD1, which is scattered in the cytoplasm in resting cells, is translocated to the plasma membrane after phorbol ester stimulation. Taken together, these data lead to the conclusion that in HT29-cl19A cells, both PLDs regulate protein transit between the trans-Golgi network and the apical plasma membrane, but that they do so at different steps in the pathway.

Towards virtual reality stimulation in force platform posturography.

We developed a stimulation technique on the basis of virtual reality methods for balance investigation performed in balance laboratories of otorhinolaryngological clinics and institutes of occupational health. Such a stimulation technique is greatly progressive in the sense that by creating virtual moving views and "virtual worlds" inside which the subject is located it is possible to make effective stimuli that would be very difficult or even impossible to set in any real environment. We tested our system on healthy subjects and found out that this kind of virtual reality stimulation system is very useful for balance analysis.

Postural control as assessed with virtual reality.

We studied the use of virtual reality technology as a stimulus in balance examinations. A pilot study was made using a small group of healthy subjects to investigate the effect of alcohol and virtual reality stimulus on the subjects' balance. The tests showed that blood alcohol concentration accounted for almost 50% of the increased lateral body sway velocity. The new stimulus technique based on virtual reality technology seems to be effective and flexible for postural investigations.

Evaluating training data suitability for decision tree induction.

Decision tree induction, as well as other inductive learning methods, requires training data of high quality to be able to generate accurate and reliable classification models. Example cases should form a representative sample from the application area, and the attributes used to describe example cases should be relevant and adequate for the classification task to be solved. In this paper, measures of the strength of association and an entropy-based approach have been used to assess the quality of the training data. Studied classification tasks related to three otological data sets: a conscript data set, a vertigo data set, and a postoperative nausea and vomiting data set. The paper suggests that the studied approaches give some guidelines about the quality of the training data, but other approaches are also needed to guide training data building.

Effects of atropine and scopolamine on bradycardia and emetic symptoms in otoplasty.

OBJECTIVE: To assess the effects of unilateral or bilateral otoplasty on bradycardia and postoperative nausea and vomiting (PONV) and the efficiency of transdermal scopolamine in the prophylaxis of PONV. STUDY DESIGN: Post hoc assessment of the data from a double-blind, randomized study. METHODS: Fifty otoplasty patients were studied; half of them received randomly and in double-blind fashion a transdermal therapeutic system (patch) of scopolamine (TTS-scopolamine) as prophylaxis against PONV before general anesthesia. The placebo group received atropine 10 microg x kg(-1) intravenously during induction. RESULTS: The scopolamine-treated patients suffered more from moderate peroperative bradycardia (8/25; P < .05) than the atropine-treated patients (1/25). Two patients wearing a half of the TTS-scopolamine patch needed intravenous atropine. After unilateral otoplasty, none of the TTS-scopolamine-treated patients and 50% of the atropine-treated patients suffered from PONV. After bilateral operation, the respective incidences were 39% and 81% (P < .01). After unilateral otoplasty no patient needed droperidol, but after bilateral otoplasty, 12 of 19 of the atropine-treated and 4 of 18 (P < .05) of the scopolamine-treated patients needed droperidol. The mean numbers of doses of droperidol were 0.8+/-0.9 and 0.3+/-0.6 (P < .05), respectively. Two additional patients, wearing half of the TTS-scopolamine patch, suffered from mild central anticholinergic syndrome. CONCLUSION: TTS-scopolamine offers effective prophylaxis against PONV (auriculoemetic reflex), but does not protect from bradycardia (auriculocardiac reflex) in otoplasty. Cutting of the TTS-scopolamine patch may lead to undesirable side effects.

Effect of learning during an anaesthesiological multicentre trial.

BACKGROUND: After the completion of a multicentre study, it was disputed whether becoming acquainted with a novel drug would affect dosing, and how many consecutive patients would be sufficient for this phenomenon. METHODS: A post hoc analysis of the data on 408 patients from a multicentre study on propofol was performed to reveal a possible learning effect. For study purposes, the patients were given consecutive anaesthetic serial numbers per anaesthesiologist. Patients eligible for the study with serial numbers 3-8 (113) were included in the initial group, and numbers 12-17 (89) in the end group. RESULTS: The patients in the end group opened their eyes (4.1 vs. 5.5 min, P < 0.05), gave their date of birth (4.5 vs. 6.3 min, P < 0.005) and walked sooner (27.1 vs. 49.8 min, P < 0.05) than the patients in the initial group. They received a higher dose of propofol at induction (2.37 vs. 2.26 mg kg-1, P < 0.05) and the last additional dose of propofol earlier (3.3 vs. 2.7 min, P < 0.05). CONCLUSION: This study shows that the learning effect can influence the results in a multicentre study. Learning contamination may occur if a novel drug is dosed by clinical judgement, and if the allocation of patients into groups is markedly uneven during the different stages of the study.

Surgeon's experience as a factor for emetic sequelae after middle ear surgery.

PURPOSE: To test the hypothesis that an experienced surgeon is associated with less postoperative nausea and vomiting (PONV). METHODS: A post hoc analysis was done on the data of 167 patients from 3 randomized studies on the prevention of PONV, with transdermal scopolamine, ondansetron and propofol, in middle ear surgery under general anaesthesia. RESULTS: The patients in the residents' group suffered more from PONV (69% vs. 42%, P < 0.01) and from retching or vomiting (52% vs. 23%, P < 0.001) than those in the specialists' group. The proportion of patients needing droperidol was also higher in the residents' group (66% vs. 27%, P < 0.001). The durations of anaesthesia and surgery seemed to correlate positively with PONV. In matched-pair analysis, residentship was confirmed as a risk factor for emetic symptoms. In the residents' group, prophylaxis of PONV resulted in a decrease in retching and vomiting from 71% to 29% (P < 0.01), and in patients needing droperidol from 87% to 46% (P < 0.01). CONCLUSION: The patients operated by residents need more aggressive prophylaxis for PONV than those operated by specialists in middle ear surgery.

Comparison of subhypnotic doses of thiopentone vs propofol on the incidence of postoperative nausea and vomiting following middle ear surgery.

BACKGROUND: Middle ear surgery is associated with a high incidence of emetic sequelae and propofol has been reported to have antiemetic activity in subhypnotic doses. METHODS: In a double-blind, randomized study, the patients received either thiopentone 1.0 mg.kg-1 (n = 26) or 0.5 mg.kg-1 propofol (n = 26) at the end of middle ear surgery under isoflurane-N2O-fentanyl-vecuronium anaesthesia. Trained nurses, unaware of the group assignment, assessed postoperative nausea, retching and vomiting up to 24 h after the end of anaesthesia. Droperidol 10 micrograms.kg-1 was used as a "rescue" antiemetic. RESULTS: The main result was that the patient in the propofol group did not suffer from retching and vomiting (R&V) during the first 6 h, whereas these symptoms occurred in 46% (P < 0.001) of the patients in the thiopentone group. The patients in the propofol group needed significantly less droperidol during the first 24 h (mean number of doses 0.39 +/- 0.57 (SD)) than the patients in the thiopentone group (1.35 +/- 1.47, P < 0.005). Treatment with propofol was a predictor for lowered incidence of R&V, as well as male gender and negative history of motion sickness. CONCLUSION: Propofol at a subhypnotic dose of 0.5 mg.kg-1 provides prophylaxis against retching and vomiting for the first 6 h postoperatively after middle ear surgery. The incidence of nausea was not reduced by propofol.

Increased incidence of retching and vomiting during periovulatory phase after middle ear surgery.

PURPOSE: To assess the effect of the menstrual cycle on postoperative retching and vomiting (R&V) after middle ear surgery, and the efficacy of prophylaxis against R&V in female patients with transdermal scopolamine during either general or local anaesthesia and with intravenous ondansetron during general anaesthesia. METHOD: A post hoc analysis of the data on 85 female patients with normal menstrual cycles from three prospective studies on the prophylaxis of postoperative nausea and vomiting after middle ear surgery on 205 patients. RESULTS: Periovulatory period (menstrual dates 11-24) and history of motion sickness were predictors for R&V. During 2-24hr, both the percentage of patients needing droperidol and the mean number of doses were lower in the perimenstrual group (menstrual dates 25-10) than in the periovulatory group 27 vs 51% (P < 0.05) and 0.2 vs 0.7 (P < 0.01), respectively. Prophylaxis with transdermal scopolamine was a predictor for lowered R&V (P < 0.05) and resulted in fewer doses of droperidol (0.4 +/- 0.7 vs 1.4 +/- 1.5, P < 0.01). This reduction was significant during the periovulatory period (from 1.4 +/- 1.3 to 0.3 +/- 0.5, P < 0.005). Ondansetron reduced the mean need for droperidol from 1.4 +/- 1.5 to 0.6 +/- 0.8, (P < 0.05). CONCLUSION: The incidence of R&V after middle ear surgery was lower during the perimenstrual phase. In the periovulatory phase, transdermal scopolamine was more efficient as prophylaxis against R&V than ondansetron. All female patients scheduled for middle ear surgery should be considered individually to receive prophylaxis against R&V.

Effect of ondansetron on nausea and vomiting after middle ear surgery during general anaesthesia.

The efficacy of ondansetron 4 mg and 8 mg was compared with placebo in the reduction of postoperative nausea, retching and vomiting (PONV) after middle ear surgery during general anaesthesia, in 75 patients, in a double-blind and randomized study. Both doses of ondansetron were predictors for a decrease in PONV and the number of doses of rescue antiemetic needed per patient (droperidol: from 0.72 in the placebo group to 0.32 in both the 4-mg and 8-mg groups). No reduction in PONV was observed in patients with a history of motion sickness, whereas in patients without a history of motion sickness, ondansetron reduced both the proportion of patients suffering from PONV from 53% to 20% (P < 0.05) and of those needing droperidol from 53% to 17% (P < 0.05).

Effect of transdermal hyoscine on nausea and vomiting during and after middle ear surgery under local anaesthesia.

The efficacy of transdermal hyoscine in the reduction of nausea, retching and vomiting was compared with placebo during and after stapedo- and tympanoplasty under local anaesthesia in a double-blind, prospective and randomized study. In the placebo group (n = 29), 69% of the patients were free from emetic symptoms during and 41% after the operation. The corresponding figures were 93% (P < 0.05) and 74% (P < 0.05) in the hyoscine group (n = 27). The patients in the placebo group needed more droperidol during and after operation (P < 0.05). The frequency of side effects was similar in both groups. In posturography the patients with emetic sequelae in the placebo group had a markedly deteriorated upkeep of posture (P < 0.05) measured as body sway velocities. A strong correlation was found between motion sickness and emetic sequelae after surgery, and patients with a history of motion sickness benefited most from hyoscine.

Effect of transdermal hyoscine on nausea and vomiting after surgical correction of prominent ears under general anaesthesia.

In a double-blind, randomized study, we have compared the efficacy of transdermal hyoscine with placebo in the reduction of nausea and vomiting in 50 patients, ASA I-II, after surgical correction of prominent ears under general anaesthesia. In the placebo group, 28%, 4% and 48% of patients suffered nausea, retching and vomiting, respectively, during the first 24 h after anaesthesia. The corresponding values in the hyoscine group were 12%, 0% and 16% (P < 0.01). In the placebo group more patients (48%) needed droperidol as an antiemetic compared with the hyoscine group (16%; P < 0.05). There was significantly more sedation in the hyoscine group.

Prevention of nausea and vomiting with transdermal hyoscine in adults after middle ear surgery during general anaesthesia.

In a double-blind, randomized study, we have compared the efficacy of transdermal hyoscine in the prevention of nausea and vomiting with placebo in 60 young, ASA I-II patients after middle ear surgery during general anaesthesia. In the placebo group, 27% and 43% of patients suffered from nausea and vomiting, respectively, during the first 24 h after anaesthesia. The corresponding values for both symptoms in the hyoscine group were 10% (P < 0.001 between groups). The frequency of side effects was similar in both groups. The results suggest that transdermal hyoscine is a useful prophylaxis against nausea and vomiting after middle ear surgery.

Nausea and vomiting after gynaecological laparoscopy depends upon the phase of the menstrual cycle.

Postoperative nausea and vomiting were compared in 68 women with regular menstrual periods undergoing gynaecological laparoscopy. The patients were divided into four group on the basis of the phase of the menstrual cycle as follows: premenstrum-menstrum (pre + menstrum) (Pd 25-6), early follicular phase (Pd 8-12), ovulatory phase (Pd 13-15) and luteal phase (Pd 20-24). The overall incidence of nausea and vomiting was 46%. Statistically significant differences in the incidence of nausea and retching were found among the groups by regression analysis. The incidence of nausea and vomiting was highest in women undergoing laparoscopy during the luteal phase (77%), which was greater than during the follicular phase (32%) or during pre + menstruation (18%). The need for antimetic was highest in women undergoing laparoscopy during the luteal phase (69%) and this was different from the follicular (18%, P less than 0.01) and pre + menstrum (19%, P less than 0.01) phases. It is concluded that the highest incidence of postoperative nausea and vomiting after gynaecological laparoscopy occurs during the luteal phase.

Tracheal intubation after induction of anaesthesia with thiopentone or propofol without muscle relaxants.

This study was designed to compare the ease of performing laryngoscopy and endotracheal intubation without muscle relaxants after the induction of anaesthesia with either thiopentone or propofol in 106 patients scheduled for elective surgery. Thiopentone (5 mg/kg) or propofol (2.5 mg/kg), supplemented with lidocaine (1.5 mg/kg) and alfentanil (30 micrograms/kg), were used in random order for the induction of anaesthesia. Jaw tone, visualisation of the larynx, position of vocal cords, ease of intubation and tolerance of the tracheal tube were assessed. The jaw was relaxed and the vocal cords were immobile/open in most patients in both groups. Visualisation of the larynx was good in 60 and 46% and intubation was easy in 48 and 22% of the patients given thiopentone and propofol, respectively (P less than 0.05 between groups for intubation). After induction of anaesthesia with thiopentone or propofol, endotracheal intubation is not recommended without the use of muscle relaxants.

Heated humidification in major abdominal surgery.

The influence of heated humidification on body temperature and postoperative shivering was studied in 30 patients undergoing major intra-abdominal surgery. In the control group (I) the anaesthetic gases, administered in a non-rebreathing system, were humidified by a sponge heat and moisture exchanger. In group II the gases were humidified and heated to 37 degrees C and in group III up to 40 degrees C. Anaesthesia, surface insulation and warming of the infusions were standardized. The temperature was registered at the lower oesophagus and the big toe. Shivering and the feeling of cold were estimated at 15 min intervals postoperatively. A good correlation was found between heat gain during the first hour of recovery, the feeling of cold and intensity of shivering. Intraoperative heat loss was minimal in all groups. Heated humidification had no statistically significant effect on the body temperatures or postoperative shivering and thus provided no additional advantage compared to the control group.