Cadmium, lead, selenium, and zinc in semen of occupationally unexposed men

Summary. Concentrations of cadmium, lead, selenium, and zinc were determined in semen and seminal plasma of 22 volunteers by atomic absorption spectrometry. Additionally conventional semen parameters and, by means of computer videomicrography, motion parameters of spermatozoa were evaluated. Concentrations of Cd, Pb, and Zn determined in semen were not significantly different from those measured in seminal plasma. However, selenium levels were significantly higher in semen (53.8 ± 22.9 μg 1⁻¹) than in seminal plasma (40.4 ± 15.5 μg 1⁻¹, P <0.01). The investigated semen samples on average contained low levels of Cd (0.4 ± 0.23 μg 1⁻¹) and Pb (9.8 ± 6.5 μg 1⁻¹). Studies on the intra-individual variability revealed the following average coefficients of variation (%) for element concentrations: Pb (70), Cd (53), Se (27), and Zn (23); and for semen parameters: total sperm count (46), sperm concentration (37), motility (22), ejaculate volume (21), linearity (19), linear velocity (11), curvilinear velocity (10), and percentage of normally formed sperm (9). Significant positive correlations were detected between semen selenium levels and sperm concentration ( r =0.51, P <0.05), and percentage of normally formed sperm ( r =0.46, P <0.05), respectively. Sperm motility ( r =0.53, P <0.02), linear ( r = 0.76, P <0.001) and curvilinear velocity ( r = 0.64, P < 0.002) were significantly correlated with semen cadmium levels.     

The influence of sperm/zona pellucida collision rates on zona binding

Summary. The satisfying success rates reported with intra-cytoplasmic sperm injection (ICSI) urged clinicians and scientists to re-address the emphasis in the management of the male factor patient towards gamete manipulation in order to circumvent the underlying problem causing fertilization failure. We have designed a study to (i) calculate the collision rate of a sperm population with the human zona pellucida, using a mathematical hypothesis and (ii) use the calculated collision rate to evaluate subsequent zona binding results obtained under hemizona assay conditions. Microdroplets were used to co-incubate sperm and human oocytes in order to evaluate zona binding. Using microvolumes, the track followed by sperm, as well as the maximum distance travelled were employed to calculate the collision rate of sperm and zona pellucida. The sperm concentrations of swim up samples were adjusted to 4 × 10⁶ and 0.8 × 10⁶ sperm ml⁻¹. Five separate droplets each of 20 μl containing 4 × 10⁶ sperm ml⁻¹ (80000 motile sperm) and 200 μl containing 0.8 × 10⁶ sperm ml⁻¹ (160000 motile sperm), respectively, were prepared. Both volumes were incubated for 18 h at 37°C. The mean (±SD) number of spermatozoa tightly bound to hemizona, incubated in 20 μl and 200 μl sperm droplets, was 2444±612 and 548±315, respectively ( P = 0.0001). The results can be used as a guideline to calculate the optimum insemination concentration needed for a specific sperm population to ensure the maximum collision rates with the oocyte.     

Treatment of acute low back pain with the COX-2-selective anti-inflammatory drug nimesulide: results of a randomized, double-blind comparative trial versus ibuprofen

STUDY DESIGN: A prospective, randomized double-blind comparative trial. OBJECTIVES: To evaluate the efficacy and tolerability of nimesulide, a cyclooxygenase (COX)-2-selective anti-inflammatory agent versus ibuprofen in patients with acute lumbosacral back pain. SUMMARY OF BACKGROUND DATA: Nonsteroidal anti-inflammatory drugs (NSAIDs) have been more effective than placebo in patients with uncomplicated acute low back pain in previous randomized controlled trials. The efficacy and tolerability of a new COX-2-selective anti-inflammatory drug have not yet been established. METHODS: One hundred four patients aged 18-65 years with acute low back pain were enrolled. The patients were randomly allocated either to oral nimesulide (100 mg twice daily for 10 days) or oral ibuprofen (600 mg three times daily for 10 days). Outcome measures on a visual analog scale were an average of the pain intensity and the pain relief, stiffness in the back, functional status, and the results of physical examinations. All side effects were recorded at each visit. RESULTS: With both study therapies, there was a clear improvement in all measured parameters of the pain and back function parameters measured from the third day of treatment onward. The patients' capacity for daily tasks, showed improvement in both groups (P < 0. 001), but a statistically significant difference was found between the two groups in favor of the nimesulide group (P < 0.05) after 10 days. Nimesulide was more effective than ibuprofen in improved lateral bending measurements (P = 0.026). Nimesulide and ibuprofen provided similar degrees of improvement in the modified Schober tests and in the pain intensity and back stiffness scores. More gastrointestinal side effects were reported with ibuprofen than nimesulide, and the comparison showed a trend (P = 0.067). Ten side effects occurred in the nimesulide group in 7 (13%) patients and 13 in the ibuprofen group in 11 (21%) patients. CONCLUSIONS: The results confirmed that the COX-2-selective inhibitor nimesulide is an effective and well-tolerated agent for use in general practices to treat acute low back pain. The incidence of gastrointestinal side effects seems to be lower with nimesulide than with ibuprofen.     

尼美舒利对二甲基苯并蒽诱导的乳腺癌的影响及机制的实验研究

目的探讨选择性环氧化酶-2(COX-2)抑制剂尼美舒利(NIM)对二甲基苯并蒽(DMBA)诱导的大鼠乳腺癌的影响及其作用机制。方法将76只大鼠随机分为致癌组(30只)、NIM组(30只)、饮食对照组(8只)及NIM药物对照组(8只),观察乳腺肿瘤诱发率。通过逆转录聚合酶链反应方法、蛋白印迹法测定每组肿瘤组织中COX-2mRNA含量及其蛋白表达水平;放射免疫法测定各组大鼠血浆、肿瘤组织中前列腺素E2(PGE2)含量;TUNEL法、增殖细胞核抗原分别检测凋亡和增殖指数。结果NIM组(40.3%)大鼠乳腺肿瘤发生率明显低于致癌组(69.2%);NIM组COX-2mRNA、蛋白水平较致癌组明显下调[A值:(0.21±0.05)vs.(0.46±0.12),P<0.05;(30.26±8.75)vs.(58.13±10.02),P<0.05],血浆、肿瘤组织中PGE2的含量显著降低[(233±59)pg/mlvs.(452±82)pg/ml,P<0.01;(167±42)pg/mg蛋白vs.(250±67)pg/mg蛋白,P<0.05];NIM组肿瘤细胞的增殖指数与致癌组相比下降[(20±5)vs.(36±5),P<0.01],凋亡指数明显增高[(43±13)vs.(18±7),P<0.01],差异有统计学意义。结论NIM通过下调COX-2的表达,抑制前列腺素的合成,抑制肿瘤细胞的增殖、诱导凋亡,降低DMBA诱发大鼠乳腺癌的发生率。     

Seminal fibronectin-like antigen and transferrin concentrations in infertile and fertile men

Summary.  Fibronectin like antigen (Fn) and transferrin (Trs) levels were measured in the seminal plasma of 40 fertile and 102 infertile men. The concentrations of both proteins were significantly ( P <0.001) higher in the fertile controls compared to the infertile groups. The levels of Fn and Trs (mean value ± SEM) in the fertile men were 857.9 ± 9.8 μg ml^-1 and 164.0 ± 6.5 μg ml^-1, respectively; in the azoospermic men ( n = 17) 552.7 ± 24.65 μg ml^-1 and 20.7 ± 2.19 μg ml^-1, respectively; in the group of severe oligozoospermia ( n = 35) 568.34 ± 25.7 μg ml^-1 and 31.1 ± 4.18 μg ml^-1, respectively; in the moderate oligozoospermic group ( n = 8) 572.50 ± 47.9 μg ml^-1 and 43.4 ± 15.4 μg ml^-1 respectively, and in the asthenozoospermic group ( n = 26) 512.76 ± 40.4 μg ml^-1 and 47.0 ± 7.9 μg ml^-1, respectively. Of special interest was the finding from a group of 16 normospermic men (partners of couples with unexplained infertility) who showed significantly lower levels of Fn like antigen, 632.5 ± 26.9 μg ml^-1 ( P <0.001) and Trs 41.8 ± 6.94 μg ml^-1 ( P <0.0001) compared to normals. No correlation was found between Fn levels with either Trs or FSH levels or sperm count. In conclusion, our results indicate that male infertility is associated with changes in seminal plasma Fn like antigen concentrations and that it can be possibly used as an index of sperm fertilizing capacity.     

Effect-site concentration of remifentanil for laryngeal mask airway insertion during target-controlled infusion of propofol

The purpose of this study was to determine the effect-site concentration of remifentanil that would provide optimal conditions for successful laryngeal mask airway insertion during a target-controlled infusion (TCI) of propofol at 3.5 μg.ml⁻¹ without the use of neuromuscular blockade. Five minutes after propofol infusion, remifentanil was infused at a dose determined by a modified Dixon's up-and-down method. Five minutes after remifentanil infusion, the laryngeal mask was inserted. The effect-site concentration of remifentanil for successful laryngeal mask insertion in 50% of adults (EC₅₀) was 3.04 (SD 0.49) ng.ml⁻¹ during a TCI of 3.5 μg.ml⁻¹ propofol without neuromuscular blockade. From the probit analysis, the EC₅₀ and EC₉₅ of remifentanil were 2.84 ng.ml⁻¹ (95% CI 2.09–3.57 ng.ml⁻¹) and 3.79 ng.ml⁻¹ (95% CI 3.26–9.25 ng.ml⁻¹), respectively.     

Increased levels of interferon-gamma in seminal plasma of infertile men

Summary. The role of the cell-mediated immunity in male infertility is still far from clear. Interferon-gamma (INF-γ), a secretory product of activated T cells and natural killer cells, has been hypothesized to have a toxic effect on sperm function. The presence of INF-γ was investigated in seminal plasma of fertile and infertile subjects, using a specific enzyme-linked immunosorbent assay, in order to study its role in male infertility. Forty-one subjects were studied; 20 had proven fertility and normal semen quality (fertile group) and 21 showed male infertility for at least 2 years and poor semen quality (infertile group). INF-γ was present in significantly higher levels in the seminal plasma of infertile subjects (6.36±0.72 fmol ml⁻¹) compared to fertile subjects (3.68±0.30 fmol ml⁻¹). Moreover, a significant negative correlation between INF-γ levels and sperm count, motility and morphology was detected, whereas no correlation between INF-γ levels and leukocyte count was found. These findings (i) confirm INF-γ to be present in seminal plasma; (ii) show increased INF-γ secretion in the infertile group; (iii) demonstrate negative correlations of INF-γ with the main spermiogram parameters and (iv) no correlation with leukocyte count. INF-γ may therefore play an important role in male infertility.
Seminal plasma—     

Acute liver failure due to a treatment by nimesulide: another case and review

Nimesulide is a non-steroidal anti-inflammatory drug available in several European countries. A hepatic toxicity due to nimesulide has been reported but fatal cases remain rare. We report the case of a 49-year-old woman treated by nimesulide during three days, admitted to the intensive care unit for an acute liver failure with encephalopathy. A temporary hepatic support by molecular adsorbent recirculating system (MARS) was performed and a hepatic transplantation was performed 12 hours after admission, allowing a rapid improvement and a discharge from intensive care unit four days after transplantation. Nimesulide induced hepatic toxicity is unpredictable and the intensity of symptomatology is variable. Clinical symptoms are often progressive, delayed from the onset of treatment. Our case draws attention to the risk of hepatic failure related to treatment with nimesulide, leading to hepatic transplantation or death. The question of risk/benefit ratio must be asked again for this widely used molecule.     

Plasma concentrations after rectal administration of acetaminophen in preterm neonates

Acetaminophen is frequently administered to infants and children for its antipyretic and analgesic properties. Oral administration is the route of choice in daily practice. In some circumstances this is impractical. Rectal administration of acetaminophen is an alternative route. This study measures plasma concentrations following rectal administration of acetaminophen 20 mg·kg⁻¹ (10% Infants' Tylenol Drops, McNeil Consumer Product Co., diluted with an equal volume of sterile water) in five preterm neonates. Serial arterial blood samples were obtained at 0, 15, 30, 60, 120, and 240 min. Pharmacokinetic parameters were (mean± sd ): C_max (maximum plasma concentration) of 8.38±3.92 μg·ml⁻¹ and T_max (time to reach maximum plasma concentration) of 78.0±40.2 min. Our results show that 20 mg·kg⁻¹ of acetaminophen rectally results in low plasma levels in preterm neonates.     

Mast cells in the seminal plasma of infertile men as detected by flow cytometry

Increased numbers of mast cells (MCs) in the testis have been associated with testicular dysfunction, where accumulation of MCs occurs. Furthermore, it has been reported that MCs might affect sperm function as it has been demonstrated that MC-derived tryptase in the seminal fluid might reduce sperm motility. Although MCs have been detected in rat epididymis, only little is known about the presence of MCs in human seminal plasma. Thus, we analysed MC numbers in the ejaculate of men during routine semen analysis of male patients suspected for infertility ( n  = 100). MCs were detected by c-kit (CD117) expression using flow cytometry. Thereby, we detected significant numbers of MCs in the ejaculate of most patients (559 ± 525 MCs ml⁻¹, mean ± SD). However, we could neither detect a correlation with respect to MCs and sperm count, motility or morphology nor to the seminal inflammatory markers like polymorphonuclear elastase. Nevertheless, a significant correlation of MCs to spermatozoa-bound IgA ( r  = 0.5; P  = 0.03; n  = 21) was observed. It is concluded that significant numbers of MCs can be detected in the human ejaculate without necessarily influencing sperm function. A potential role of MCs in seminal plasma as well as the association between MCs and IgA on spermatozoa remains to be elucidated.     

Microflora of the seminal fluid of healthy men and men suffering from chronic prostatitis syndrome

Chronic prostatitis syndrome (CPS) is a common urologic condition that many clinicians find difficult to diagnose and treat effectively. The information about the composition of the flora of the seminal fluid in healthy men and patients with CPS is limited. The aim of this study was to define the microbial communities present in the seminal fluid of healthy men and patients with CPS and at in vitro detection of decomplementary activity (DCA) phenotypes of isolates along with their comparison with isolates from patients with or without CPS. The bacteriological study was carried out to 48 healthy men and 60 men with CPS. Culture specimens were spread on various selective media. Bacterial DCA was tested by measuring the decrease in complement activity (CH₅₀) under the influence of culture supernatants. The most common isolates in both groups were coryneforms, lactobacilli, coagulase-negative staphylococci, micrococci and streptococci. Enterobacteriaceae, enterococci and Staphylococcus aureus were isolated only from the CPS group. The organisms from seminal fluid of healthy men exerted DCA at 3.56 ± 2.15; 2.47 ± 1.23 and 4.36 ± 2.2 anti-CH₅₀ for staphylococci, micrococci and diphtheroids respectively. The DCA of staphylococci, coryneforms, Enterobacteriaceae, enterococci and micrococci from CPS group were 12.8 ± 2.1 ( p  <   0.05), 4.4 ± 3.6 ( p  >   0.05), 16.8 ± 2.1, 7.2 ± 1.9 and 11.6 ± 3.3 ( p  < 0.05) anti-CH₅₀ respectively. The data obtained in this study testify the microecological disorders in microbiota of seminal fluid in CPS.     

Correlation between neutral alpha-glucosidase activity and sperm DNA fragmentation

To evaluate the association between neutral α-glucosidase (NAG) activity and sperm DNA fragmentation (DFI), ejaculates from 24 men undergoing evaluation for sperm DNA damage as a part of infertility assessment were analysed. The mean ± SD and range for the semen quality of the 24 ejaculates are as follows: volume (3.1 ± 1.3, 1.8–6.0 ml); sperm concentration (45.6 ± 41.1, 1.3–151.2 × 10⁶ ml⁻¹); sperm motility (52.8 ± 28.8, 1–95%); sperm with fragmented DNA (17.6 ± 15.4, 1.7–56.0%); sperm with immature chromatin (9.6 ± 3.8, 2.5–19.1%); NAG activity (37.9 ± 18.3, 4.4–75.3 mU ml⁻¹). The only sperm parameter significantly correlated with neutral α-glucosidase is the percentage of sperm DFI [correlation coefficient ( r ) = 0.4376, P  = 0.03].     

Potency and maintenance requirement of atracurium and vecuronium given alone or together

A synergism exists between some competitive muscle relaxants. However, maintenance requirement of a combination of muscle relaxants has been evaluated only in paediatric patients. We studied 45 elective adult surgical patients (ASA I-II) during propofol-alfentanyl-N₂O-O₂-anaesthesia. The first 30 patients were randomized to receive either atracurium or vecuronium to create individual dose-response curves for these muscle relaxants. ED₉₅-values for atracurium and vecuronium were 260±9 and 59±3 μg · kg^-1, respectively (mean±s.e.mean). Requirements of atracurium and vecuronium to maintain an 85–95% neuromuscular blockade were 301 and 83 μg kg^-1 h^-1, respectively. An additional 15 patients received a combination of atracurium and vecuronium (cAV) in an equipotent dose ratio. An ED₉₅ of a cAV was 94± 7 μg · kg^-1 of atracurium together with 21±2 μg · kg^-1 of vecuronium, or 72±6% of one ED₉₅ dose of a parent agent. Potentiation was significant ( P =0.0001). A maintenance requirement of a cAV was 120 μg kg^-1 h^-1 of atracurium together with 27 μg kg^-1 h^-1 of vecuronium. Thus, a significant potentiation was maintained also during the course of anaesthesia. A cAV had an effect like one intermediate-acting agent. If a cAV is used instead of using atracurium or vecuronium alone, the maximal reduction of drug consumption would be approximately 30%.     

Lack of effect of flumazenil on the reversal of propofol anaesthesia

Propofol, like the benzodiazepines, activates the GABA_A receptor-chloride ionophore complex; they potentiate one another. Since neither pharmacodynamic nor pharmacokinetic data concerning drug interaction between flumazenil and propofol is available, and especially considering the relationship of binding sites, flumazenil, the antagonist of benzodiazepines, was investigated to determine its effect upon recovery from propofol anaesthesia. Forty women receiving dilatation and curettage procedures were included in this double-blind test. After 50 μg fentanyl, propofol 2 mg · kg^-1 was injected for induction and followed by infusion at the rate of 15 mg · kg^-1 · hr^-1. After the operation, patients were given normal saline (Group A) or flumazenil 10 μg · kg^-1 (Group B) randomly.
Recovery time in Group A was 15.2±5.1 min and Group B 15.8±4.8 min. Propofol concentrations at the end of infusion were 4.17±1.33 μg ·ml^-1 (Group A) and 4.03±1.45 μg · ml^-1 (Group B); these then declined to 1.22±0.17 μg · ml^-1 (Group A) and 1.18±0.15 μg · ml^-1 (Group B) when patients were able to open their eyes on command. No significant differences were found between the groups based on propofol concentrations and recovery time, nor did haemodynamic changes differ between them after administration of reversal agents. It was concluded that flumazenil 10 μg · ml^-1 does not influence recovery from propofol anaesthesia.     

Quantifying the interaction of vecuronium with enflurane using closed-loop feedback control of vecuronium infusion

The influence of different levels of enflurane anaesthesia on infusion requirements of vecuronium was studied in 40 adult surgical patients. Ninety percent neuromuscular block was maintained by computer controlled infusion of vecuronium. During the first 90 min study period all patients received fentanyl-nitrous oxide-oxygen (2:1) anaesthesia. For the following 90 min the patients were randomly assigned to receive enflurane at different end-tidal concentrations: group I, control, fentanyl-nitrous oxide anaesthesia; group II, enflurane 0.3%-nitrous oxide; group III, enflurane 0.6%-nitrous oxide; group IV, enflurane 0.9%-nitrous oxide. Every patient served as his/her own control and the changes of vecuronium infusion requirements were determined individually. When the administration of enflurane was started, vecuronium infusion requirements decreased progressively until 90 min. In group II the infusion rate lowered from 80±28 to 56±20 μg . kg^-1 . h ^-1, in group III from 61 ±29 to 34±17 μg . kg^-1 . h^-1 and in group IV from 65±20 to 30± 14 μg . kg^-1 . h^-1. In the control group the infusion rate decreased during the three hour study period from 69± 17 (first 90 min period) to 59± 16 μg . kg^-1 . h^-1 (second 90 min period). Enflurane reduces the dose requirements of vecuronium administered by continuous infusion in a dose- and time-dependent manner.     

A comparison of opioid solutions for patient-controlled epidural analgesia

Sixty patients took part in a randomised, double-blind study to compare the analgesic and side effects of three opioid-containing solutions for patient-controlled epidural analgesia following abdominal surgery. Patients in group 1 received a solution containing bupivacaine 0.125% with fentanyl 10μg. ml⁻¹, group 2 bupivacaine 0.125% with diamorphine 125μg. ml⁻¹, group 3 pethidine 2.5 mg. ml⁻¹. All groups received 4 ml.h⁻¹ background infusion and 3 ml boluses every 20 min if necessary. There were no significant differences between the groups in visual analogue scale pain scores (p = 0.537) or volumes of solution used at 24 h (p = 0.351) or 48 h (p = 0.105). Motor block was significantly higher in group 2 (p < 0.004) and pruritis occurred significantly less in group 3 (p < 0.05). We conclude that these three solutions produce equivalent analgesia but that pethidine 2.5 mg. ml⁻¹ may be associated with fewer side effects.     

Plasma bupivacaine levels after fascia iliaca compartment block with and without adrenaline

Twenty children undergoing unilateral surgery on the thigh received a fascia iliaca compartment block using 2 mg·kg⁻¹ of bupivacaine with (Group A) or without (Group P) adrenaline 1/200 000. Venous blood samples were taken as 5, 10, 15, 20, 25, 30, 40, 50 and 60 min after injection and assayed for concentrations of bupivacaine. In all subjects an adequate block was produced. Plasma concentrations of bupivacaine in Group P were significantly higher than those in Group A ( P <0.05). The median maximum plasma concentration (C_max) was 1.1 μg·ml⁻¹ (range 0.54–1.29 μg·ml⁻¹) in Group P and 0.35 μg·ml⁻¹ (range 0.17–0.96 μg·ml⁻¹) in Group A. The median time taken to attain C_max (T_max) was 20 min (range 10–25 min) in Group P and 45 min (range 5–50 min) in Group A. The median time to first analgesia was 9.75 h (range 3–15 h) in Group P and 10.5 h (range 2.5–21 h) in Group A. The study confirmed the efficacy of the fascia iliaca compartment block in children and showed that when performed with 2 mg·kg⁻¹ of bupivacaine it is associated with plasma concentrations of bupivacaine well within acceptable limits. The addition of adrenaline 1/200 000 to the local anaesthetic solution reduces the maximum plasma concentration reached.     

Treatment of de Quervain disease with triamcinolone injection with or without nimesulide. A randomized, double-blind, placebo-controlled trial

BACKGROUND: There is uncertainty as to whether supplemental oral nonsteroidal anti-inflammatory medication improves the effectiveness of steroid injections in the treatment of de Quervain disease. We tested the hypothesis that there are no significant differences in the success rates when this condition is treated with triamcinolone injection with or without supplemental oral nimesulide. METHODS: In a randomized, double-blind trial, 160 patients with de Quervain disease received an injection of 10 mg of triamcinolone acetonide and either 200 mg of oral nimesulide for seven days (eighty patients) or placebo tablets for seven days (eighty patients). An independent, blinded evaluator assessed the primary outcomes (tenderness, pain, and the result on the Finkelstein test) at three weeks after injection. Adverse reactions were assessed, and probabilities of recurrence for both groups were compared. Factors possibly predictive of disease recurrence were also assessed. RESULTS: The success rate after one injection was 67% in the nimesulide group and 68% in the placebo group. The overall success rates after single or multiple injections with a mean follow-up of 13.6 months were 95% for both groups. No significant differences were noted with respect to the success rates (p = 0.69) or pain scores after treatment (p = 0.11). The most common adverse reactions to triamcinolone injection and nimesulide were pain after injection and dyspepsia, respectively. The symptoms of de Quervain disease recurred in 33% of the patients in the nimesulide group and in 37% of those in the placebo group. The median time of recurrence was at the fifth month in the nimesulide group and at the fourth month in the placebo group. The recurrence of symptoms was significantly (p = 0.01) related to the presence of crepitation (relative risk, 2.13; 95% confidence interval, 1.19 to 3.80). CONCLUSIONS: Supplemental oral administration of the nonsteroidal anti-inflammatory drug nimesulide does not improve the effectiveness of a single injection of triamcinolone acetonide in the treatment of de Quervain disease. Patients with crepitation in the first dorsal compartment during thumb extension or abduction are at increased risk for recurrence of this disease. LEVEL OF EVIDENCE: Therapeutic study, Level I-1b (randomized controlled trial [no significant difference but narrow confidence intervals]).     

The duration of action of mivacurium is prolonged if preceded by atracurium or vecuronium

We studied 45 patients (ASA I-II) during propofol-alfentanil-N₂O-O₂ anaesthesia to determine if recovery from neuromuscular block induced by mivacurium is influenced differently by prior injection of atracurium or vecuronium. Neuromuscular function was monitored by adductor pollicis EMG. Patients were randomized to receive two dosesof either mivacurium (150 and 70 μg kg^-1), atracurium (350 and 75 μg kg^-1) or vecuronium (70 and 15 μg kg^-1) followed by a final dose of mivacurium 70 μg kg^-1. The second and third doses of the muscle relaxants were administered at 25–30% recovery of the E₁ (first EMG response in the train-of-four series). Following the final dose of mivacurium, the EMG response recovered to 25 and 95% in 10.4±3.9 and 19.7±5.7 min (mean±SD), respectively, if mivacurium was the only muscle relaxant. Respective times were 100% longer if mivacurium had been preceded by atracurium (23.8 ± 3.3 and 39.8±6.9 mm) or vecuronium (22.6±3.5 and 44.1 ±7.9 min) ( P =0.000l). The 25–75% recovery times in the three groups were 4.9±1.0, 8.7±2.4 and 10.5±2.5 min, respectively ( P =0.0001). Our results indicate that there is no benefit in giving mivacurium at the end of surgery after peroperative use of atracurium or vecuronium.