A comparison of the pharmacodynamics of rocuronium and vecuronium during halothane anaesthesia.

Thirty healthy patients were randomised to receive either a single bolus dose of rocuronium 0.6 mg.kg-1 or vecuronium 0.1 mg.kg-1 during halothane anaesthesia. Onset time, duration 25, duration 75 and train-of-four 70 were measured. The onset of neuromuscular blockade following rocuronium was more rapid than vecuronium (p = 0.0001). All other pharmacodynamic parameters were similar. During the first minute following injection of the neuromuscular blocking agent, the heart rate increased by 36% in the rocuronium group but remained stable in those patients who received vecuronium (p = 0.0008). No adverse effects were noted in either group.

Applications and complications of tissue expansion in pediatric patients.

We have reviewed our experience with 61 tissue expansions in 49 pediatric patients. Indications for expansion included traumatic alopecia or soft tissue loss, myelomeningocele, congenital hairy nevi, burn scars, and other less common defects. The complication rate, necessitating interruption of expansion, was 25%. This occurred more frequently with scalp and burn reconstruction. Nevertheless, 86% of patients ultimately achieved good to excellent results.

Management of perineal wounds following abdominoperineal resection with inferior gluteal flaps.

Our experience treating perineal wounds secondary to abdominoperineal resection, either for inflammatory bowel disease or cancer, is presented. A total of 16 patients were treated either on a delayed basis or at the same time as the abdominoperineal resection. All wounds were closed using the inferior gluteal myocutaneous flap. Fifteen of 16 patients have achieved healing, eight of whom had no complications. Only minor revisions or local wound care were required in the remaining patients, with only one patient failing to heal. Our results compare favorably with previous reports of treatment of this difficult problem.

The subcutaneous forehead lift.

A limited experience (27 patients, all female) is presented utilizing the subcutaneous approach to forehead lifting. This approach has been little utilized and has been condemned in the literature for being dangerous. However, no difficulties in wound healing or alopecia have been encountered, and the procedure has the advantages of more effectively removing the vertical and transverse wrinkles in the glabellar region, raising the brows, and preserving sensation to the scalp posterior to the incision.

Forehead reconstruction with a modified radial forearm flap: a case report.

Forehead reconstruction, using a radial forearm flap with opposing long arterial and venous pedicles, is presented. Advantages of this flap design are discussed.

Antagonism of vecuronium and atracurium: comparison of neostigmine and edrophonium administered at 5% twitch height recovery.

In 39 healthy patients antagonism, by neostigmine 0.07 mg kg-1 or edrophonium 0.8 mg kg-1, of neuromuscular blockade induced by vecuronium or atracurium, was compared. Reversal was attempted when the height of the single twitch (TH) had recovered spontaneously to 5% of the control value. The evoked responses, initially single twitch, then train-of-four (TOF) were observed until the TOF ratio was 70%. Induced recovery from TH 5% to 25% was shorter following edrophonium than following neostigmine with both vecuronium (P less than 0.05) and atracurium (P less than 0.05). The recovery indices and times until TH was 75% of control and until the TOF ratio was 70% were not different. The time from a TH of 75% to a TOF ratio of 70% was shorter following neostigmine than following edrophonium with both vecuronium (P less than 0.01) and atracurium (P less than 0.01). Edrophonium had a much more variable effect on vecuronium than on atracurium. These results show that although the onset of action of edrophonium was faster than that of neostigmine, this did not lead to a faster clinical recovery, and antagonism by edrophonium may be delayed in a number of patients if vecuronium is the neuromuscular blocker.

Antagonism of profound neuromuscular blockade induced by vecuronium or atracurium. Comparison of neostigmine with edrophonium.

The effectiveness of neostigmine 0.07 mg kg-1 and edrophonium 0.8 mg kg-1 as antagonists of profound neuromuscular blockade induced by vecuronium 0.1 mg kg-1 or atracurium 0.5 mg kg-1 was studied in 59 healthy patients. The antagonists were administered 5 min after total ablation of the twitch response and the end-point of recovery was a train-of-four ratio of 70%. In 30 patients given vecuronium the mean time to reach this point (duration TOF70) was 66.7 min in the control group (no antagonist), 43.5 min in the group given neostigmine and 59.8 min in the group given edrophonium. The duration TOF70 was shorter in the neostigmine group than in the control (P less than 0.01) and edrophonium (P less than 0.01) groups. The duration TOF70 did not differ from control in the edrophonium group. In 29 patients given atracurium, the durations TOF70 were 66.4, 44.1 and 54.9 min in the control, neostigmine and edrophonium groups, respectively. The durations TOF70 in the neostigmine (P less than 0.01) and edrophonium (P less than 0.01), groups were shorter than control. The duration TOF70 of the neostigmine group was shorter than in the edrophonium group (P less than 0.01). These results show that profound neuromuscular blockade cannot be rapidly antagonized by either of these two agents, but if reversal is required under these circumstances, neostigmine would be the more effective drug.

Reversal of atracurium with edrophonium.

The antagonistic action of a bolus dose of edrophonium 0.75 mg kg-1 on the neuromuscular blockade induced by atracurium was studied in 10 patients anaesthetized with nitrous oxide and narcotic supplements. The reversal agent was administered when the twitch height had recovered spontaneously to approximately 20% of control. Twitch response was restored to 100% of control after 4.7 +/- 2.2 min. Clinically adequate reversal (train-of-four ratio of 75% or better) was achieved 6.6 +/- 1.5 min following injection of the edrophonium and there was no evidence of subsequent muscle weakness. The possible advantages of the clinical use of edrophonium in producing a rapid reversal of atracurium blockade are discussed.

Clinical studies on Org NC 45: comparison with pancuronium.

Some actions of Org NC 45 have been compared with those of pancuronium in a study on 50 patients anesthetized with nitrous oxide and narcotic supplements. The train-of-four technique was used to assess the recovery of neuromuscular blockade and its antagonism. Org NC 45 was shown to have a duration of action from injection of the intubating dose (0.1 mg kg-1) to the reappearance of the first twitch response of 23.5 +/- 1.1 min; the corresponding time for pancuronium 0.1 mg kg-1 was 50.5 +/- 3.6 min. Recovery time from the initial incremental dose to the reappearance of the first train-of-four response was 11.6 +/- 0.8 min with Org NC 45 and 31 +/- 4.7 min with pancuronium. No evidence of cumulation was seen following several incremental doses of Org NC 45. The rate of onset of paralysis of adductor pollicis was faster with Org NC 45 than with pancuronium, but the difference did not reach statistical significance. Satisfactory spontaneous recovery from Org NC 45 blockade could be achieved without undue delay. Org NC 45 was shown to produce significantly less tachycardia.

Some actions of Org NC 45 and of edrophonium in the anaesthetized cat and in man.

Some actions of the muscle relaxant drug Org NC 45 on the tibialis anterior muscle of cats under barbiturate-chloralose anaesthesia have been studied. Its effects were characteristic of a neuromuscular blocking agent that acts predominantly, although not necessarily exclusively, by blocking postjunctional cholinoceptors. It was confirmed that one of the important features of the action of Org NC 45 is that, despite its high potency, its offset of action is unusually rapid. The pronounced antagonism of the block following an interposed tetanus suggested that Org NC 45 is more easily displaced from the endplate cholinoceptors than are tubocurarine or pancuronium, and this led to the idea, confirmed by experiment, that edrophonium would be a more effective antagonist of Org NC 45 than of most other neuromuscular blocking drugs. Edrophonium was about 12 times less potent than neostigmine in antagonizing Org NC 45. However, with equipotent antagonistic doses, edrophonium restored transmission to control (as measured by the train-of-four test) at least twice as rapidly as neostigmine and, more importantly, edrophonium had a much weaker effect than neostigmine on the cardiac vagus. The results obtained in cats with edrophonium were essentially confirmed in preliminary studies on nine anaesthesized patients. In these studies, a dose of edrophonium 0.5 mg kg-1 i.v. was found to produce adequate and rapid antagonism of Org NC 45, and because of the relatively weak side-effects of edrophonium, it was necessary, about 30 s before edrophonium, to administer only 0.6 mg of atropine (about 9 micrograms kg-1), which is half the dose commonly used when neostigmine is the reversal agent. These preliminary observations in man suggest that edrophonium may be the reversal agent of choice for Org NC 45.

Change in size distribution of active polyribosomes associated with puff induction in Drosophila melanogaster salivary glands.

The polytene cells of Drosophila melanogaster larvae are ideally suited for the study of gene information flow during differentiation, in that gene derepression is visualized in the form of chromosomal modifications called puffs. One special group of temperature-sensitive puffs can be experimentally induced within 5 min after transfer of salivary glands from 24-37 degrees C. Glands at 37 degrees C also begin synthesizing several new polypeptides which are of higher molecular weight than the prominent polypeptides being synthesized in glands at 24 degrees C [1]. The present study demonstrates that there is also a shift toward the utilization of heavier or more rapidly sedimenting polyribosomes for protein synthesis in glands transferred from 24-37 degrees C. As a result of such studies it is reasonable to assume that the polyribosome redistribution after a heat shock results from the translation of larger mRNA molecules synthesized by the temperature-sensitive loci. Further studies are suggested to describe the role of heat-induced gene activity in maintaining homeostasis, as well as the manner by which such activity is induced, in cells subjected to dramatic temperature fluctuations.