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UNLABELLED: We compared the effects of i.v. tramadol (1.25 mg/kg), codeine (1 mg/kg), morphine (0.125 mg/kg), and saline on gastric emptying in 10 healthy human volunteers using a double-blind, randomized, cross-over design. Subjects received one treatment at each of four sessions, 2 wk apart. Gastric emptying was studied using the paracetamol absorption test. There were significant differences when comparing all treatments for concentration-time data (P = 0.002), peak serum paracetamol concentrations (Cmax; P < 0.001), times at Cmax (Tmax; P = 0.003), and areas under the curves from Time 0 to 360 min (AUC(0-360); P = 0.049). Morphine profoundly inhibited gastric emptying. Tramadol had measurable but statistically insignificant inhibitory effects on gastric emptying compared with saline (mean +/- SEM: Cmax 22.4 +/- 2.2 vs 26.8 +/- 2.5 mg/L [P = 0.19], Tmax 33 +/- 5.4 vs 19.5 +/- 2.3 min [P = 0.054] for tramadol versus saline, respectively). Compared with morphine, the Cmax (P < 0.01), Tmax, and AUC(0-360) (P < 0.05) values for tramadol were significantly different. The Tmax value for codeine (63.3 +/- 11.7) was greater than that for tramadol (P = 0.034). We conclude that tramadol has a measurable but smaller inhibitory effect on gastric emptying compared with other opioids. IMPLICATIONS: We compared the effect of tramadol, an unconventional opioid painkiller, on stomach emptying with that of codeine and morphine in a human volunteer study. Tramadol had a measurable but smaller effect and may have clinical and economic advantages in acute pain management compared with conventional painkillers.

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A case of anaphylaxis to a latex urethral catheter in a 33-year-old at full term pregnancy is presented. The diagnosis is based on clinical findings and supported by subsequent immunological tests. She was managed with cardiopulmonary resuscitation, concomitant caesarean section and intravenous adrenaline. Despite the good maternal outcome the child showed early signs of severe perinatal asphyxia, the long-term sequelae of which remain to be seen. This report discusses this unusual cause of anaphylaxis and highlights the problems of resuscitation in the pregnant patient.

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Predispensed gradient matrices allow the boundary between precipitate and clear solution to be located very rapidly for a particular protein and precipitant. In many cases crystals grow in the trials which were used to identify this boundary. The method involves dispensing a series of between 10 and 72 microbatch trials in which some parameter, such as precipitant concentration, is gradually changed. (Protein is not dispensed at this stage.) Protein is then added to selected trials using a predetermined algorithm, which takes into account the level of precipitation caused by previous additions. Thirteen crystal forms were obtained using the method with eight proteins and eight precipitants. Six forms were prisms or plates with maximum dimensions above 400 microm.

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Recent developments of the IMPAX system for automated crystallization are presented. A five-channel microtip has been introduced into the system thereby providing an extra degree of freedom for carrying out experiments. A new mouse-driven program for screening has been introduced, which creates a much wider scope for designing and executing screens covering new conditions of crystallization. The hardware has been adapted so that the system can also be used to set up vapour-diffusion trials. A simple design of a vapour-diffusion vessel, suitable for sitting drops of 2-15 microl, using smaller reservoir volumes (up to 100 microl), facilitates large-scale systematic trials.

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The automated microbatch technique developed at Imperial College has been used to establish a phase diagram for crystallization. The concentrations of the protein (carboxypeptidase G2) and precipitant (PEG 4000) were varied, while pH and temperature were kept constant. The diagram consists of an undersaturation and a supersaturation zone, the latter being subdivided into the metastable, nucleation and precipitation zones. In the metastable zone, crystals may grow but nucleation of crystals does not occur. It is the best zone for growth of X-ray diffraction quality crystals because of the slower growth rate and the avoidance of uncontrolled nucleation, which uses up protein in the formation of tiny crystals. Nevertheless, in practice, it is rarely well defined or used because nuclei must be introduced artificially into the system. The new method used here consists of setting crystallization droplets at nucleation conditions and later diluting them to conditions where nucleation has not been observed. Single diffracting crystals of typical dimensions 0.3 x 0.3 x 0.2 mm were routinely obtained in the metastable zone, equivalent to the best (very rarely) obtained crystals in the nucleation zone.

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Forests of Ankarana limestone massif in northern Madagascar support one of the largest and least disturbed populations of Crowned Lemurs, Lemur coronatus. This paper reports a preliminary study of the ecology of this species in the Ankarana Special Reserve conducted at the end of the dry season in 1986, with additional information collected a year later. Crowned Lemurs occur in very high densities in the semi-deciduous canopy forest and this probably represents a dry season refuge for the species. They also use more open habitats, including sparsely vegetated limestone and degraded forest. Sanford's Lemur, Lemur fulvus sanfordi, also inhabits the Ankarana forests but is most abundant in degraded habitats. Crowned and Sanford's Lemurs had similar patterns of activity, which included nocturnal travelling and feeding bouts. Crowned Lemurs proved to be unusual among Lemur species in displaying low spatial troop cohesion and a lack of obvious troop hierarchy. Stronglyoides-like enteric helminths infested about one third of Crowned Lemurs but were apparently not causing disease. Crowned Lemurs fall prey to the Fosa, Cryptoprocta ferox, and the young possibly also to the largest raptors. A total of seven living lemur species (including the very rare Propithecus diadema perrieri and Daubentonia madagascariensis) were confirmed at Ankarana by the authors, and three further species have been reported by other observers. In addition to these ten extant lemurs, four subfossil species have been discovered: three of them (Hapalemur simus, Palaeopropithecus and Mesopropithecus) by the authors. The possibility that all 14 lemurs were once sympatric is discussed. For the present, the lemurs of Ankarana are protected from hunting by local taboo. Nevertheless they are under severe threat from habitat destruction, despite Ankarana's Special Reserve status. Given the very restricted distributions of Crowned and Sanford's Lemurs, both must be considered as threatened with extinction.

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