Planaria which have cannibalized untrained planaria exposed to photic stimuli only, handling only, or previous conditioning, all require significantly fewer trials in a conditioning situation than naive planaria.

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Serum bupivacaine concentrations during continuous extrapleural infusionPurpose: To determine the rate of increase in serum bupivacaine concentration during continuous extrapleural infusion. Methods: After thoracotomy for Iobectomy under general anaesthesia, nine patients had an extrapleural catheter inserted, before chest closure, in a costovertebral gutter constructed surgically by lifting the parietal pleura. Bupivacaine 0.5% with epinephrine 1:200,000 was injected through the catheter as 0.3 ml-kg t bolus followed by 0. I ml.kg J.hr ~ for live days. Serum bupivacaine (free and total), albumin, alpha-I acid gtycoprotein concentrations were measured 15 min after injection and at 24 hr intervals for five days. Bupivacaine concentrations were determined by column liquid chromatography using solid phase extraction. Serum alpha-I acid glycoprotein concentration was determined by nephelometry on QM 300 protein analyzer. Serum albumin concentration was determined by bromocresol green dye binding procedure on Hitachi 717 Autoanalyzer. Results: A continuous elevation in total serum bupivac~ne was observed, with an average value of 0.75 Hg.ml on day 1 to 2.77/Jg-ml -~ on day 4 (P<0.05). There was no increase in postoperative free serum bupivacaine concentration; average value of 177 pcg'ml ~ on day I and 249 pcg.ml-~ on day 4 (P =0.92). Postoperative serum alpha-I acid glycoprotein concentration showed a steady rise with an average value of 0.94 Hg-ml ~ on day I and t.47 ~g-ml ' on day 4 (P<0.05). No change was observed in post-operative serum albumin with an average value of 31.4 g.I + on day I and 31.3 g.N on day 4. Conclusion: Continuous extrapleural infusion of bupivacaine over live days after thoracotomy is associated with a steady increase in total serum bupivacaine concentration and no elevation in free serum bupivacaine concentration.Objectif : DEterminer la vitesse de raccumulation s&ique de la bupivaca'ine pendant une perfusion extrapleurale continue. M&hodes : AprEs une thoracotomie pour Iobectomie sous anesthEsie gEnErale, on a insErE avant la fermeture de la plaie un catheter extrapleural ~ neuf patients dans une goutti&e costovertEbrale cr6Ee chirurgicalement par soulcSvement la plEwe pariEtale. De la bupivacaine 0,5% adrEnalinEe h 1:200,000 en bolus de 0,3 ml-kg ~ suivi d'une perfusion de 0,

Hexafluorobicyclo[2,2,0] hexa-2,5-diene reacts with chlorine or with bromine in the dark to give a mixture of the corresponding exo,exo-and trans-5,6-dihalogenohexafluorobicyclo[2.2,0] hex-2-enes; further, photochemical reaction with halogen gives a mixture of all-exo-and exo,exo,exo,endo-2,3,5,6-tetrahalogenohexafluoro[2,2,0] hexanes. Catalytic hydrogenation of the diene a t -50" gives exo-5H,6H/-hexafluorobicyclo[2.2.0] hex-2-ene. Hydrogen bromide adds photochemically to the diene to give mainly the bicyclohexene arising from cis.exoaddition ; cis,exo-addition of bistrifluoromethyl nitroxide to one or both double bonds of the diene is also favoured.The diene is susceptible to nucleophilic displacement of olefinic fluorine atoms ; controlled reaction with the nucleophiles sodium methoxide, dimethylamine, methyl-lithium, and sodium borohydride leads to the formation of the appropriate 2-substituted pentafluorobicyclo[2,2,0] hexa-2.5-diene. With potassium benzenethiolate, only the 2.5-disubstituted derivative is formed. Sodium borohydride gives only the 2.6-dihydro-derivative. The diene reacts slowly with lithium halides in dimethylformamide to give halogenopentafluorobenzenes. and with caesium fluoride in formarnide to give mainly exo-5H-heptafluorobicyclo[2,2,0] -hex-2-ene.The n.m.r. spectra of the derived bicyclo[2,2,0] -hexa-2,5-dienes, -hex-2-enes, and -hexanes have been partially or completely analysed. The '@F chemical shifts are particularly useful in deciding the configuration of these compounds. The hexadienes show certain characteristic ranges of F,F coupling constants, viz. low values of the four-bond coupling of olefinic fluorines (0-1.6 Hz), substantial five-bond coupling of olefinic fluorines (9.2-14.7 Hz), and substantial three-bond coupling of bridgehead fluorines (7-1 4.5 Hz). In the bicyclohexanes, the cross-ring coupling of endo-fluorines is very substantial (ca. 40 and 24 Hz) ; this possibly arises from a ' throughspace contribution '. The C X stretching frequencies of the hexadienes and hexenes, which more nearly resemble those of polyfluorocyclohexenes than those of polyfluorocyclobutenes, are interpreted in terms of a possible contribution from deformation of a long C-C bond between the 1and 4-positions.