An evaluation of strategies for restoring a degraded New Zealand scallop fishery using stochastic dynamic simulation modelling.

A decision-theoretical approach was used to evaluate strategies to rebuild a severely depleted scallop (Pecten novaezelandiae) populations in the Tasman Bay and Golden Bay of New Zealand. These strategies were: no intervention, cessation of seabed bottom contact fishing, and reduction of sediment and nutrient runoff from surrounding land through on-farm practices. Our approach combined outputs of estimated effects of on-farm practices on erosion and nutrient reduction with a stochastic dynamic model of the scallop populations. The most effective individual intervention is eliminating bottom contact fishing through dredging and trawling which increased scallop biomass on average by 73% compared to the no intervention scenario. Although on-farm practices have reduced sedimentation and nutrient runoff significantly (28-36% and 2%, respectively), they have no effect on scallop biomass if implemented individually and led to only marginal improvements in scallop biomass if implemented alongside cessation of bottom contact fishing (2-4%). Although our results showed, on average, substantial recovery in the scallop population when reducing seabed bottom contact and water pollution, the large uncertainty boundaries makes it unclear whether these improvements would be realized. The long-term success of such strategies will depend on the available habitat being able to sustain high densities of healthy scallop adults and recruits, a situation that has been posited in our analysis. Where scallop juvenile survival is compromised by sedimentation, nutrient pollution, or other exogenous influences, proposed interventions may be insufficient to aid recovery.

An uncertain future: Effects of ocean acidification and elevated temperature on a New Zealand snapper (Chrysophrys auratus) population.

Anthropogenic CO2 emissions are warming and acidifying Earth's oceans, which is likely to lead to a variety of effects on marine ecosystems. Fish populations will be vulnerable to this change, and there is now substantial evidence of the direct and indirect effects of climate change on fish. There is also a growing effort to conceptualise the effects of climate change on fish within population models. In the present study knowledge about the response of New Zealand snapper to warming and acidification was incorporated within a stock assessment model. Specifically, a previous tank experiment on larval snapper suggested both positive and negative effects, and otolith increment analysis on wild snapper indicated that growth may initially increase, followed by a potential decline as temperatures continue to warm. As a result of this uncertainty, sensitivity analysis was performed by varying average virgin recruitment (R0) by ±30%, adult growth by ±6%, but adjusting mean size at recruitment by +48% as we had better evidence for this increase. Overall adjustments to R0 had the biggest impact on the future yield (at a management target of 40% of an unfished population) of the Hauraki Gulf snapper fishery. The most negative scenario suggested a 29% decrease in fishery yield, while the most optimistic scenario suggested a 44% increase. While largely uncertain, these results provide some scope for predicting future impacts on the snapper fishery. Given that snapper is a species where the response to climate change has been specifically investigated, increasing uncertainty in a future where climate change and other stressors interact in complex and unpredictable ways is likely to be an important consideration for the management of nearly all fish populations.

Transplant-related experience in pharyngo-oesophageal reconstruction: use of organ preservation techniques to improve ischaemic tolerance in free jejunal flaps.

Reconstruction of pharyngo-oesophageal defects remains a surgical challenge. Free jejunal flaps, first described by Seidenberg in 1959, are used to reconstruct circumferential defects, but their main disadvantage is sensitivity to ischaemia. Others are secretions, an unpleasant smell, and problems at the donor site. To improve the tolerance of the jejunal segment to ischaemia and to give the surgeon more time, we cool it after harvest and flush it with organ preservation fluid. We describe the technique in a small case series of seven patients.

Inhibition of hepatobiliary transporters by a novel kinase inhibitor contributes to hepatotoxicity in beagle dogs.

PF-022 (1) is a novel polycyclic benzothiophene kinase inhibitor selective for mitogen-activated protein kinase-activated protein kinase 2 (MK2). Compound 1 emerged as an inhibitor bearing submicromolar potency against MK2 (IC50 5 nM) and demonstrated projected human pharmacokinetics sufficient for oral dosing. However, following a single, oral administration of 1 to beagle dogs, animals experienced an acute liver injury characterized by increases in biomarkers associated with hepatotoxicity; particularly noteworthy was the reversible elevation in bile salts and total bilirubin. Accompanying this observation was an ADME appraisal which included hepatic bioactivation of 1 in multiple species and the in vitro inhibition of P-glycoprotein (P-gp; IC50 21 µM). Simply attenuating the bioactivation via structural modification proved ineffective in improving the in vivo tolerability of this polycyclic scaffold. Hence, disruption of hepatobiliary transporters by the compound series was hypothesized as the likely mechanism contributing to the acute hepatotoxicity. Indeed, closer in vitro examination employing transporter gene overexpressing MDCK cell lines and membrane vesicles revealed potent compound-dependent inhibition of human multi-drug resistance-associated protein 2 (MRP2/ABCC2; IC50 38 µM) and bile salt export pump (BSEP/ABCB11; IC50 10 µM), two crucial hepatobiliary transport proteins accountable for bilirubin and bile salt homeostasis, respectively. Subsequent introduction of pKa-altering modifications to a second generation compound PF029 proved successful in reducing its affinity for these key efflux transporters (MRP2 IC50 >>80 µM; BSEP IC50 > 70 µM; P-gp > 90 µM), consequently mitigating this overt organ toxicity in dogs.

Biodegradable fixation in oral and maxillofacial surgery.

UNLABELLED: Fixation of the maxillofacial skeleton following trauma or osteotomy surgery has been achieved by the use of titanium plates and screws for the past two decades. Advances in materials science has enabled the development of biodegradable or resorbable plates and screws for internal fixation of the maxillofacial skeleton. This paper presents the biochemistry of resorbable materials and our early experiences in their clinical applications. CLINICAL RELEVANCE: This manuscript illustrates the use of a resorbable material to fix the maxillofacial skeleton following osteotomies and trauma.