[Genitourinary manifestations of lymphoma]

Non-Hodgkin lymphoma (NHL) of the genitourinary system is a very rare disease. Only 1 % of NHL are primary genitourinary lymphomas, most commonly of testicular origin. Secondary infiltration from disseminated lymphoma can be found in all the genitourinary organs. We report on five patients with genitourinary lymphoma who were diagnosed at our department: one case of primary testicular lymphoma and four patients with secondary lymphomatous infiltration of kidney, bladder, prostate and testicles, respectively. The clinical courses are described and the current literature is reviewed. The operation could be restricted to a biopsy for assurance of the diagnosis. However, the mostly radical procedures are performed for curative purposes after an incorrect diagnosis of a malignant organ cancer without even recognizing or considering NHL in the differential diagnosis.

Nerve regeneration using tubular scaffolds from biodegradable polyurethane

INTRODUCTION

In severe nerve lesion, nerve defects and in brachial plexus reconstruction, autologous nerve grafting is the golden standard. Although, nerve grafting technique is the best available approach a major disadvantages exists: there is a limited source of autologous nerve grafts. This study presents data on the use of tubular scaffolds with uniaxial pore orientation from experimental biodegradable polyurethanes coated with fibrin sealant to regenerate a 8 mm resected segment of rat sciatic nerve.

METHODS

Tubular scaffolds: prepared by extrusion of the polymer solution in DMF into water coagulation bath. The polymer used for the preparation of tubular scaffolds was a biodegradable polyurethane based on hexamethylene diisocyanate, poly(epsilon-caprolactone) and dianhydro-D-sorbitol. EXPERIMENTAL MODEL: Eighteen Sprague Dawley rats underwent mid-thigh sciatic nerve transection and were randomly assigned to two experimental groups with immediate repair: (1) tubular scaffold, (2) 180 degrees rotated sciatic nerve segment (control). Serial functional measurements (toe spread test, placing tests) were performed weekly from 3rd to 12th week after nerve repair. On week 12, electrophysiological assessment was performed. Sciatic nerve and scaffold/nerve grafts were harvested for histomorphometric analysis. Collagenic connective tissue, Schwann cells and axons were evaluated in the proximal nerve stump, the scaffold/nerve graft and the distal nerve stump. The implants have uniaxially-oriented pore structure with a pore size in the range of 2 micorm (the pore wall) and 75 x 700 microm (elongated pores in the implant lumen). The skin of the tubular implants was nonporous. Animals which underwent repair with tubular scaffolds of biodegradable polyurethanes coated with diluted fibrin sealant had no significant functional differences compared with the nerve graft group. Control group resulted in a trend-wise better electrophysiological recovery but did not show statistically significant differences. There was a higher level of collagenic connective tissue within the scaffold and within the distal nerve stump. Schwann cells migrated into the polyurethane scaffold. There was no statistical difference to the nerve graft group although Schwann cell counts were lower especially within the middle of the polyurethane scaffold. Axon counts showed a trend-wise decrease within the scaffold.

CONCLUSION

These results suggest that biodegradable polyurethane tubular scaffolds coated with diluted fibrin sealant support peripheral nerve regeneration in a standard gap model in the rat up to 3 months. Three months after surgery no sign of degradation could be seen.

Sozialräumliche Clusteranalyse der Kreise und kreisfreien Städte und Gesundheitsindikatoren in NRW

OBJECTIVE

North Rhine-Westphalia (NRW's) indicator set for health reporting activities comprises more than 70 regional health indicators, which means that these data are available for health reporting purposes for all 54 districts and urban districts. Morbidity and mortality indicators differ in part quite considerably and require further interpretation. With the help of selected indicators, the authors of the following article try to explain the relation between social status and health status.

METHODOLOGY

Ten years ago, NRW, as part of its health reporting activities, started to carry out multivariate analyses to classify socio-demographically different types of regions, leading to the establishment of six types of regions which can be linked to health-related data. Social structure indicators are part of a first step submitted to a main component analysis and grouped together by a small number of features and/or factors which clearly reflect differences in living conditions. As a result, two factors were extracted: an economic prosperity factor which is mainly determined by the disposable income and a so-called A-factor which mainly describes the fact that poorer, elderly, unemployed and foreign population groups live concentrated in regions with a declining population but high population density. These factors are, in a second step, used for a cluster analysis aimed at classifying the 54 districts and urban districts and at establishing different types of regions. In a subsequent step, the cluster method is used to explain regional variations of selected health indicators.

RESULTS

It is a proven fact that morbidity and mortality are influenced by social status. With the help of selected indicators, six clusters with a different socio-economic structure influencing the health status of the population can be established for NRW. Special attention should be paid to the cluster of the Ruhr area with its below-average social situation. With 90% NRW's population primarily living within the other 5 clusters which are differently structured but increasingly adjusting their living conditions to each other. The authors of this publication assign four health status indicators to predefined clusters and analyse the relation between the social and health status: female and male life expectancy, the proportion of underweight live births, infant mortality and avoidable deaths.In regions with high A-factor values (poverty pole), i. e., in several ways socially deprived regions, male and female average life expectancy is significantly lower than in regions with a clearly less pronounced accumulation of problems. Moreover, a significantly higher life expectancy for male live births can be observed in regions with a high disposable income. The model fails to establish a convincing correlation between social status and infant mortality and breast cancer.

CONCLUSIONS

Knowledge about socio-demographic differences in the health status of the population is particularly important for prevention measures in order to be able to react appropriately to health risks in districts and urban districts. The analysis shows that an intense regional accumulation of problems will have a negative influence on health status, an influence which is more significant than the positive influence of prosperous regions on the health status.

Hémangiome vaginal révélé par un saignement chez une petite fille : à propos de 1 cas

We report on the case of a 9-year-old girl who presented vaginal bleeding which led to the diagnosis of vaginal hemangioma. Such localisation is rare, and requires a clinical follow-up by vaginoscopy. A spontaneous regression can be expected but, at this time, the progress of puberty and future fertility are unknown.

Impact of ABO blood groups on tirofiban mediated inhibition of platelet function

Previous investigations revealed that ABO blood groups are associated with divergent concentrations of several coagulation factors. Concentrations of von Willebrand factor (vWF) and factor VIII are lower in individuals with blood group O as compared to subjects with blood group A, B or AB which might result in a reduced inhibition of platelet aggregation. The aim of the present in-vitro-investigation was to elucidate the impact of ABO blood group dependent vWF concentrations on tirofiban mediated inhibition of GPIIb/IIIa function. Platelet function was measured with the platelet function analyzer PFA-100 at baseline and at increasing concentrations of tirofiban and stratified for blood group O vs. A. If measured with the collagen/epinephrine cartridge, blood group O was associated with a prolonged mean baseline closure time in comparison with blood group A (175.8 +/- 64.9 s vs. 121.4 +/- 33.4 s, p = 0.037) which was paralleled by reduced concentrations of vWF and factor VIII. In contrast, no differences in closure time (227.6 +/- 76.1 s vs. 223.9 +/- 81.9 s, p = 0.96) could be found in the presence of tirofiban (0.1 microg/ml). Thus, tirofiban mediated GP IIb/IIIa receptor antagonism as determined with the PFA-100 seems to be independent on plasma concentration of vWF.

Aldosterone Blunts Human Baroreflex Sensitivity by a Nongenomic Mechanism

BACKGROUND

Impaired baroreflex sensitivity (BRS) is a negative predictive factor of mortality in cardiovascular disease. Aldosterone has been shown to decrease BRS in humans and animal models. However, the mode of aldosterone action, whether genomic or nongenomic has not been determined. Therefore, we conducted a clinical study to examine whether BRS, as measured by the phenylephrine method, is impaired in humans by aldosterone by a nongenomic mechanism.

METHODS

In a randomised, double-blinded, fourfold cross-over trial in 16 healthy male volunteers, BRS was tested 15 minutes after initiation of a continuous infusion of aldosterone (3 microg/minute) or placebo. 6 hours earlier, this period was preceded by an injection of either canrenoate (400 mg) or placebo.

RESULTS

BRS was 34.6 +/- 4.7 ms/mm Hg in the placebo/placebo period. It was significantly blunted in the placebo/aldosterone (25.5 +/- 1.8 ms/mm Hg) as well as in the canrenoate/placebo (24.0 +/- 1.5 ms/mm Hg) and the canrenoate/aldosterone (25.4 +/- 2.5 ms/mm Hg) periods.

CONCLUSION

These data suggest that the decreased BRS caused by aldosterone is due to a rapid, thus presumably nongenomic mechanism, as these effects occur in a time frame that excludes genomic aldosterone effects at large. The mineralocorticoid receptor (MR) antagonist canrenoate does not block these effects, but blunts BRS by itself.

Evaluation of the VIDAS Listeria (LIS) immunoassay for the detection of Listeria in foods using demi-Fraser and Fraser enrichment broths, as modification of AOAC Official Method 999.06 (AOAC Official Method 2004.06)

A multilaboratory study was conducted to compare the VIDAS LIS immunoassay with the standard cultural methods for the detection of Listeria in foods using an enrichment modification of AOAC Official Method 999.06. The modified enrichment protocol was implemented to harmonize the VIDAS LIS assay with the VIDAS LMO2 assay. Five food types--brie cheese, vanilla ice cream, frozen green beans, frozen raw tilapia fish, and cooked roast beef--at 3 inoculation levels, were analyzed by each method. A total of 15 laboratories representing government and industry participated. In this study, 1206 test portions were tested, of which 1170 were used in the statistical analysis. There were 433 positive by the VIDAS LIS assay and 396 positive by the standard culture methods. A Chi-square analysis of each of the 5 food types, at the 3 inoculation levels tested, was performed. The resulting average Chi square analysis, 0.42, indicated that, overall, there are no statistical differences between the VIDAS LIS assay and the standard methods at the 5% level of significance.

Empfehlungen zur Statintherapie im Alter

Elderly patients are significantly less likely to receive statins than younger patients possibly because of doubts regarding compliance or concerns regarding the increased likelihood of adverse events and drug interactions. Poor compliance can be expected especially in patients suffering from dementia or depression as well as those whose stage of cardiovascular disease exhibits few symptoms. On the other hand, the clinical significance of CHD events is high in the elderly, and 80% of coronary deaths occur in patients aged over 65 years. The average statistical life expectancy of elderly and old patients is often underestimated. The HPS and PROSPER studies showed that statins reduce mortality and morbidity even in very elderly individuals with a high global cardiovascular risk and/or CAD. Patients up to the age of 79 years should be treated according to the same guidelines as younger patients. Statin therapy should only be considered for patients aged 80 years and older who are at a very high risk for cardiovascular events.

Evaluation of the BAX system for detection of Listeria monocytogenes in foods: collaborative study

A multilaboratory study was conducted to compare the automated BAX system and the standard cultural methods for detection of Listeria monocytogenes in foods. Six food types (frankfurters, soft cheese, smoked salmon, raw, ground beef, fresh radishes, and frozen peas) were analyzed by each method. For each food type, 3 inoculation levels were tested: high (average of 2 CFU/g), low (average of 0.2 CFU/g) and uninoculated controls. A total of 25 laboratories representing government and industry participated. Of the 2335 samples analyzed, 1109 were positive by the BAX system and 1115 were positive by the standard method. A Chi square analysis of each of the 6 food types, at the 3 inoculation levels tested, was performed. For all foods, except radishes, the BAX system performed as well as or better than the standard reference methods based on the Chi square results.

[The Narcotrend monitor. Development and interpretation algorithms]

The Narcotrend performs an automatic interpretation of the electroencephalogram (EEG) during anaesthesia. The classification algorithms have been developed on the basis of visually classified EEG epochs. The classification scheme which was used for these visual assessments has its origin in sleep analysis and was adapted for the EEG during anaesthesia. From the awake state to very deep anaesthesia, 15 stages (A, B(0-2), C(0-2), D(0-2), E(0-2), F(0-1)) are distinguished. The transformation of these stages into a numerical scale from 100 to 0 is a further refinement for a differentiated presentation of EEG effects. For the automatic classification multivariate discriminant functions are used. Age-related changes of the EEG were incorporated. The device contains functions for the identification of artifacts. The EEG can be recorded from a frontal channel using standard ECG electrodes, other electrode positions and types can be chosen. The device has been clinically and scientifically validated.

The Narcotrend Index: Classification Algorithm, Correlation with Propofol Effect-Site Concentrations, and Comparison with Spectral Parameters / Der Narcotrend-Index: Klassifikationsalgorithmus, Korrelation mit Propofol-Effekt-Site-Konzentrationen und Vergleich mit Spektralparametern

A reliable assessment of the depth of hypnosis during sedation and general anaesthesia using the EEG is a subject of current interest. The Narcotrend Index implemented in the latest version 4.0 of the EEG monitor Narcotrend provides an automatic classification of the EEG on a scale ranging from 100 (awake) to 0 (very deep hypnosis, EEG suppression). The classification algorithms implemented in the EEG monitor Narcotrend are described. In a study the correlation of the propofol effect-site concentration with the Narcotrend Index and with the traditional spectral parameters total power, relative power in the standard frequency bands delta, theta, alpha, and beta, median frequency, 95% spectral edge frequency, burst-compensated spectral edge frequency, and spectral entropy was investigated. The Narcotrend Index had the highest average correlation with the propofol effect-site concentration and the smallest variability of the individual correlation values. Moreover, the Narcotrend Index was the only parameter which showed a monophasic trend over the whole investigated time period. The Narcotrend monitor can make a significant contribution to the improvement of the quality of anaesthesia by adjusting the dosage of hypnotics to individual patient needs.

Delayed genomic and acute nongenomic action of glucocorticosteroids in seasonal allergic rhinitis

BACKGROUND

Glucocorticosteroids are effective in the treatment of allergic rhinitis, a disease characterized by a variety of symptoms, e.g. rhinorrhea and itching. The time course of symptomatic relief for allergic rhinitis by steroids has not been examined in detail to date, although the onset of steroid action is one of the main discriminations between genomic and nongenomic actions of steroids. We therefore investigated the time course of subjective and objective measures of nasal affection after steroid administration in patients with allergic rhinitis following specific allergen challenge.

METHODS

Six female and 18 male volunteers (median age 26 years) with a history of allergic rhinitis but currently free of symptoms were included in this randomized, placebo-controlled, double-blind, three-period crossover study. A single dose of either betamethasone (60 mg), methylprednisolone (400 mg) or placebo was given intravenously, 5 min after intranasal allergen provocation. After 10, 20, 60, 150 and 240 min, nasal itching and nasal obstruction were assessed using a standardized visual analogue scale. In addition, nasal airflow was measured by anterior rhinomanometry.

RESULTS

Nasal itching was markedly reduced following either of the two steroids within 10 min after administration of study drug. Itching was depressed by 38% following betamethasone (P<0.05) and by 18% following methylprednisolone (P=0.07) compared with placebo. Nasal airflow and nasal obstruction were not significantly altered by steroids during the first 2 h of the study. However, after 150 min, nasal airflow was 21% rsp. 19% higher after methylprednisolone and betamethasone (P<0.05) compared with placebo. After 240 min, nasal airflow was increased by 20% following betamethasone (P<0.05) and by 19% following methylprednisolone. Nasal obstruction was also beneficially affected by both steroids 150 and 240 min after administration compared with placebo (P<0.05 for both time points following betamethasone).

CONCLUSION

This study for the first time shows rapid in vivo effects of external glucocorticosteroids in humans. Itching, a pathophysiologically complex sensation, is favourably influenced by steroids within 10 min, therefore presumably via nongenomic mechanisms. Though no detailed mechanisms can be derived from this study, steroid interaction with receptors in the central nervous system may play an important role in mediating this effect.

Age-related effects in the EEG during propofol anaesthesia

BACKGROUND

Age-related differences in the spectral composition of the EEG in induction and emergence times, and in drug consumption during propofol anaesthesia were investigated.

METHODS

The EEGs of 60 female patients between 22 and 85 years of age were monitored continuously during standardized induction of anaesthesia with 2 mg of propofol kg(-1)60 s(-1). The EEGs were visually assessed in 20-s epochs according to a scale from A (awake) to F (very deep hypnosis). Visual EEG classifications, spectral parameters, and induction times were compared between different age groups. Additionally, data of 546 patients included in a multicentre study with 4630 patients (EEG monitor Narcotrend, MT MonitorTechnik, Bad Bramstedt, Germany) were analyzed with regard to age-dependent changes of propofol consumption using target-controlled infusion (TCI).

RESULTS

During induction, patients older than 70 years reached significantly deeper EEG stages than younger patients, needed a longer time to reach the deepest EEG stage, and needed more time until a light EEG stage was regained. In patients aged 70 years and older, the total power, mainly in deep EEG stages, was significantly smaller due to a distinctly smaller absolute power of the delta frequency band. No single spectral parameter was able to reliably distinguish all EEG stages. During the steady state of anaesthesia, older patients needed less propofol for the maintenance of a defined stage of hypnosis than younger patients.

CONCLUSION

Older patients differ from younger ones regarding the hypnotic effect of propofol and the spectral patterns in the EEG. For an efficient automatic assessment of the EEG during anaesthesia a multivariable approach accounting for age-effects is indispensable.

Evaluation of long-term quality of life after reoperative coronary artery surgery: preliminary results

OBJECTIVE

The risks of reoperative coronary artery bypass surgery (RECABG) still exceed those of a primary revascularisation and late results are not very favourable either. The subject of the present study is an evaluation of the long-term quality of life after RECABG.

METHODS

We studied the outcome of 541 patients who underwent a RECABG from January 1987 to December 1998. The endpoint of the study was December 2002, or the patient's death. Quality of life, using the EuroQol registration, was evaluated.

RESULTS

Hospital mortality was 6.7%. Follow-up was 95.6% complete, mean 7.7 years. There were 177 late deaths. The cumulative survival rates were 83.8, 76.9, and 60.6%, and cardiac survival rates were 84.8, 78.5, and 66.5%, at the one-year, five-year and ten-year follow-up, respectively. For 255 patients (89%), NYHA and EuroQol information was complete. In total 23% of the patients were in NYHA class I, 51% in class II, 21% in class III and 5% were in class IV. In the EuroQol registration, 54% of the patients declared they had no mobility problems, 85% no problems with self-care, and 65% no problems with usual activities. However, 60% suffered from moderate pain or discomfort, and 33% from anxiety or depression. On the visual analogue scale (mean 63.5), 13% of the patients scored >90, 68% between 50 and 90, and 19% of the patients <50.

CONCLUSION

The long-term results of cumulative survival and cardiac survival, and NYHA class in our patient population who underwent RECABG are comparable with other studies. Quality of life is acceptable regarding the high risk of a RECABG.

Influence of EEG monitoring on intraoperative stapedius reflex threshold values in cochlear implantation in children

BACKGROUND

Cochlear implantation is a widely used means of treating deafness and severe hearing disorders. The surgical procedure includes inserting the cochlear implant electrode array into the cochlea and embedding the corresponding signal receiver in the mastoid bone behind the ear. Postoperative fitting of the externally worn speech processor is very important for successful use of the cochlear implant. For this purpose, electrically elicited stapedius reflex threshold values can be used. However, stapedius reflex threshold values measured intraoperatively are influenced by anaesthetics. The goal of this retrospective study was to find out whether electroencephalogram (EEG) control of anaesthesia produces more reliable reflex threshold values as a basis for the fitting of the speech processor.

METHODS

Three groups of children, after surgery for cochlear implantation, were analysed with regard to the magnitude of intraoperative electrically elicited stapedius reflex threshold values and their deviations from postoperatively determined maximum comfortable levels (group 1: methohexital/remifentanil with EEG monitoring, n = 10; group 2: isoflurane/fentanyl with EEG monitoring, n = 9; group 3: isoflurane/fentanyl without EEG monitoring, n = 11).

RESULTS

Children with EEG monitoring had significantly lower electrically elicited stapedius reflex threshold values and also significantly lower differences between intraoperative stapedius reflex threshold values and postoperatively determined maximum comfortable levels.

CONCLUSIONS

Electroencephalogram monitoring in cochlear implantation is of considerable value in controlling anaesthesia and improving speech processor fitting based on more reliable intraoperative neurophysiological data.

The regulatory domain of protein kinase Ctheta localises to the Golgi complex and induces apoptosis in neuroblastoma and Jurkat cells

This study investigates apoptotic effects of protein kinase C (PKC) delta and theta in neuroblastoma cells. 12-O-tetradecanoylphorbol-13-acetate induces apoptosis in SK-N-BE(2) neuroblastoma cells overexpressing PKCdelta or PKCtheta, but not PKC epsilon. The PKC inhibitor GF109203X does not suppress this apoptotic effect, suggesting that it is independent of the catalytic activity of PKC. The isolated catalytic domains of PKCdelta and PKCtheta or the regulatory domain (RD) of PKCtheta also induce apoptosis in neuroblastoma cells. The apoptotic responses are suppressed by caspase inhibition and by Bcl-2 overexpression. The PKCtheta RD induced apoptosis also in Jurkat cells. Colocalisation analysis revealed that the PKCtheta RD primarily localises to the Golgi complex. The C1b domain is required for this localisation and removal of the C1b domain results in a PKCtheta construct that does not induce apoptosis. This suggests that the PKCtheta RD has apoptotic activity and that Golgi localisation may be important for this effect.

Alterations in platelet function during the ovarian cycle

Steroid hormones may profoundly influence hemostasis; for example, as discussed for hormone replacement therapy, pregnancy and, being less obvious, for the ovarian cycle. We investigated primary hemostasis parameters using a platelet function analyzer (PFA-100) during the follicular and luteal phases in 18 healthy young women without oral contraceptives. During the follicular phase, the mean closure time (CT) was 164.7 +/- 56.7 s, and it decreased to 130.2 +/- 30.6 s in collagen/epinephrine cartridges in the luteal phase (P = 0.0095). No significant difference could be found for CT values in collagen/adenosine diphosphate cartridges during the follicular phase as compared with the luteal phase (97.2 +/- 24.2 s versus 89.6 +/- 18.4 s, P = 0.174). Negative correlations between the CT values in collagen/epinephrine cartridges and von Willebrand factor from both phases of the cycle were found (follicular phase: r = -0.53; luteal phase: r = -0.54). Fibrinogen and fibrinogen degradation products were significantly increased in the luteal phase (2.49 +/- 0.62 g/l versus 2.05 +/- 0.59 g/l and 0.12 +/- 014 versus 0.04 +/- 0.04, P = 0.02 for both parameters) as compared with the follicular phase. No significant differences could be detected for plasminogen, plasmin-antiplasmin complex, prothrombin fragment 1 + 2 and D-dimer between the groups. This study indicates that platelet function is periodically altered during the ovarian cycle due to the influence of progesterone and estrogen on von Willebrand factor concentrations.

Seminal plasma hormone concentration after oral application of progesterone

Previous studies have revealed beneficial in vitro effects of progesterone on sperm function. The aim of this pilot study was to prove if orally given micronized progesterone leads to elevations in progesterone and/or 17alpha-hydroxyprogesterone levels in seminal plasma, since higher seminal plasma levels of these hormones could possibly have a beneficial effect on sperm function as seen in in vitro investigations. Multiple application of micronized progesterone given over 4 days (daily dose 400 mg) to 6 healthy subjects resulted in elevated seminal plasma levels of progesterone (10.90 +/- 9.02 nmol/l vs. 1.43 +/- 0.56 nmol/l, p = 0.04) and 17alpha-hydroxyprogesterone (3.09 +/- 1.72 nmol/l vs. 1.62 +/- 1.26 nmol/l, p = 0.04) whereas no significant difference could be found in testosterone levels (34.82 +/- 13.00 vs. 30.91 +/- 8.56 nmol/l, p = 0.43). In contrast, androstendione levels in seminal plasma were reduced (2.68 1.28 nmol/l vs. 3.65 +/- 1.36 nmol/l, p = 0.01). Although micronized progesterone is rapidly metabolized, oral application resulted in pronounced elevations of progesterone and 17alpha-hydroxyprogesterone in seminal plasma. Further studies will show if oral application of micronized progesterone can induce beneficial effects on sperm function such as those seen in in vitro investigations.

Automatic classification algorithms of the EEG monitor Narcotrend for routinely recorded EEG data from general anaesthesia: a validation study

Impacts of hypnotic drugs on brain function are reflected in the EEG. The EEG monitor Narcotrend performs an automatic classification of the EEG using a scale which was proposed by Kugler for visual evaluation of the EEG. In this article the results of a validation study of the automatic classification algorithms implemented in the EEG monitor Narcotrend are presented. Visual and automatic classification of EEG data recorded in routine clinical practice were compared. The correlation between visual and automatic assessment was high (Spearman rank correlation r = 0.90, prediction probability Pk = 0.90) and a sufficient agreement between visual and automatic assessment was achieved for 92% of the analysed EEG epochs. The results of the study suggest that the automatic classification algorithms implemented in the EEG monitor Narcotrend yield a reliable assessment of the depth of hypnosis.