Morphological analysis of sticklebacks from Misty Lake and its inlet stream (Keogh River system, northern Vancouver Island) reveals two forms of Gasterosteus. Sticklebacks from the lake are large and slender bodied with a black back and sides, while sticklebacks from the inlet stream are smaller with a stockier body and mottled brown back and sides. Lake fish also have shorter jaws, longer spines, and more gill rakers than the stream fish. These differences in body shape, trophic structures, and colour are inherited, and the two forms breed true in the laboratory. This implies that they are independent gene pools rather than a single gene pool containing some complex polymorphism. The pair from Misty lake and stream is compared with ecologically similar pairs from Graham Island in the Queen Charlotte Archipelago. The lake–stream pairs on the two islands are strikingly similar. Two hypotheses are examined that might explain the origins and remarkable resemblance of these widely disjunct lake–stream pairs. One hypothesis is historically based and argues that the lake–stream pairs on northern Vancouver Island and the Queen Charlotte Islands share a common origin. The other hypothesis argues that the similarities between the lake–stream pairs on the two islands are the result of parallel evolution (i.e., independent evolution of similar phenotypes in response to similar selection regimes). The available data do not allow a distinction to be made between the hypotheses. The historical hypothesis, however, argues for a divergence that predates the Fraser glaciation, whereas the parallel-evolution hypothesis requires postglacial divergence. Since the two hypotheses differ in the amount of time available for divergence, it may be possible to distinguish between the hypotheses at the molecular level.

We investigated differences in the morphological and behavioural contributions to foraging success among three morphotypes (open-water, littoral, and intermediate) of the threespine stickleback (Gasterosteus aculeatus) from a single drainage system on Vancouver Island. Stomach contents from wild samples showed diet to be dependent on morphotype. Interpopulation differences in trophic morphology were associated with differences in foraging success on given prey types. The longer jaw of the bottom-browsing littoral morphotype allowed it to ingest significantly larger prey then either the intermediate or open-water populations. In addition, the littoral type spent less time manipulating benthic prey then either the open-water or intermediate morphotype. The latter observation is independent of interpopulation differences in jaw length. Both the planktivorous open-water morphotype and intermediate morphotypes were superior foragers in experiments on water column prey. The differences in water column foraging success are associated with interpopulation differences in gill raker morphology. Our results support the conclusion that inter population divergence in trophic phenotype is an adaptive response to differences in the primary trophic resources available in lakes of different morphometry.

To assess interpopulation levels of morphological variability populations of Gasterosteus aculeatus were sampled from lakes within the upper Cowichan River system (Vancouver Island, British Columbia). Phenotypic divergence between populations is assumed to be a postglacial event. Nine characters were scored; eight were related to feeding and the ninth character was lateral plate number. All populations were the low plate morph; however, populations of Gasterosteus in lakes lacking piscivorous fish had significantly fewer lateral plates than populations in lakes with predatory fish species. Two distinct trophic "morphotypes" were identified, each one associated with a specific lake environment. Populations inhabiting benthic-dominated environments were found to possess reduced gill raker number and reduced gill raker length but increased upper jaw length relative to populations from limnetic environments. We propose that the interpopulation variability in trophic morphology is a response to trophic resource differences between lakes.

A multivariate solution for dealing with patterns of character covariance, when character genotypic covariances are known, has been applied to the organization of trophic morphology among lacustrine populations of the threespine stickleback (Gasterosteus aculeatus). The quantitative genetics governing eight trophic characters were investigated using representative populations from each of three known trophic ecotypes (open-water, littoral, and intermediate) which occur in the same drainage. Character heritabilities (0.19–0.84) were all significant. Estimates of character genetic correlations (−0.65 < rG < 0.85) were obtained and their standard errors were calculated by bootstrapping. Cluster analyses of the genetic correlation matrices defined two character suites, head shape and gill raker structure. Selection gradients between trophic ecotypes indicated that directional selection had operated most strongly on characters related to food size (upper jaw length and gill raker number). These results support the hypothesis that interpopulation variability in trophic morphology is organized as an adaptive response to local selection pressures.

Purpose: Chloroprocaine should be an ideal agent for intravenous regional anesthesia (IVRA) because of its rapid onset and ester hydrolysis. Raising the pH of local anesthetics may increase the speed of onset and the intensity of nerve blocks. We compared plain and alkalinized 2-chloroprocaine 0.5% with lidocaine for IVRA.Methods: In two seporate double-blind studies, 78 patients scheduled for daycare hand surgery were randomized to receive 40 mL plain 2-chloroprocaine 0.5%, alkalinized 2-chloroprocaine 0.5% or lidocaine 0.5% for IVP~. Time to sensory and motor block, need for supplemental analgesia, and side effects were compared. Kesults: There was no difference in time to sensory or motor block in either group. Patients who received plain chloroprocaine required more supplemental opioid and had a higher incidence of metallic taste and of hives than patients who received lidocaine (P < 0.05). Comparing alkalinized chloroprocaine with lidocaine, there was no difference found with respect to opioid supplementation, CNS side effects, or incidence of hives. Conclusion: In conclusion, alkalinized chloroprocaine was found to be an effective agent for IVRA but no benefit over lidocaine was detected. Plain chloroprocaine for IVRA produced more minor side effects than lidocaine.Objectif: La chloroprocaTne est un agent ideal pour ranesth&ie r~gionale intraveineuse (ARIV) &ant donn6 sa rapidit~ d'action et I'hydrolyse des esters. En ~levant le pH des anesth&iques Iocaux, on peut acc~l&er le d~but de I'action et augmenter I'intensit~ des blocages nerveux. Nous avons compar~ la 2-chloroproca'fne simple 0,5 % et alcalinis~e avec la lidoca'fne pour une ARIV.M&hode : II y a eu deux ~tudes s~por4.es, ~ double insu, aupr& de 78 patients dont I'op&ation d'une main avait