Evidence that divergent selection shapes a developmental cline in a forest tree species complex.

Background and Aims: Evolutionary change in developmental trajectories (heterochrony) is a major mechanism of adaptation in plants and animals. However, there are few detailed studies of the variation in the timing of developmental events among wild populations. We here aimed to identify the climatic drivers and measure selection shaping a genetic-based developmental cline among populations of an endemic tree species complex on the island of Tasmania. Methods: Seed lots from 38 native provenances encompassing the clinal transition from the heteroblastic Eucalyptus tenuiramis to the homoblastic Eucalyptus risdonii were grown in a common-garden field trial in southern Tasmania for 20 years. We used 27 climatic variables to model the provenance variation in vegetative juvenility as assessed at age 5 years. A phenotypic selection analysis was used to measure the fitness consequences of variation in vegetative juvenility based on its impact on the survival and reproductive capacity of survivors at age 20 years. Key Results: Significant provenance divergence in vegetative juvenility was shown to be associated with home-site aridity, with the retention of juvenile foliage increasing with increasing aridity. Our results indicated that climate change may lead to different directions of selection across the geographic range of the complex, and in our mesic field site demonstrated that total directional selection within phenotypically variable provenances was in favour of reduced vegetative juvenility. Conclusions: We provide evidence that heteroblasty is adaptive and argue that, in assessing the impacts of rapid global change, developmental plasticity and heterochrony are underappreciated processes which can contribute to populations of long-lived organisms, such as trees, persisting and ultimately adapting to environmental change.

Assessment of the financial implications for laparoscopic liver surgery: a single-centre UK cost analysis for minor and major hepatectomy.

BACKGROUND: Laparoscopic hepatectomy is progressively gaining popularity. However, it is still unclear whether the laparoscopic approach offers cost advantages compared with the open approach, especially when major hepatectomies are required. Data providing useful insights into the costs of the laparoscopic approach for clinicians and hospitals are needed. The aim of this study is to assess the financial implications of the laparoscopic approach for two standardized minor and major hepatectomies: left lateral sectionectomy and right hepatectomy. METHODS: A cost comparison analysis of patients undergoing laparoscopic right hepatectomy (LRH) and laparoscopic left lateral sectionectomy (LLLS) versus the open counterparts was performed. Data considered for the comparison analysis were operative costs (theatre cost, consumables and surgeon/anaesthetic labour cost), postoperative costs (hospital stay, complication management and readmissions) and overall costs. RESULTS: A total of 149 patients were included: 38 patients underwent LRH and 46 open right hepatectomy (ORH); 46 patients underwent LLLS and 19 open left lateral sectionectomy (OLLS). For LRH the mean operative, postoperative and overall costs were £10,181, £4,037 and £14,218; for ORH the mean operative, postoperative and overall costs were £6,483 (p < 0.0001), £10,304 (p < 0.0001) and £16,787 (p = 0.886). Regarding LLLS, the mean operative, postoperative and overall costs were £5,460, £2,599 and £8,059; for OLLS the mean operative, postoperative and overall costs were £5,841 (p = 0.874), £5,796 (p < 0.0001) and £11,637 (p = 0.0001). CONCLUSION: Our data support the cost advantage of the laparoscopic approach for left lateral sectionectomy and the cost neutrality for right hepatectomy.

Laparoscopic liver resection for hepatocellular adenoma.

AIM: To investigate the role of laparoscopy in the surgical management of hepatocellular adenoma (HA). METHODS: We reviewed a prospectively collected database of consecutive patients undergoing laparoscopic liver resection for HA. RESULTS: Thirteen patients underwent fifteen pure laparoscopic liver resections for HA (male/female: 3/10; median age 42 years, range 22-72 years). Two patients with liver adenomatosis required two different laparoscopic operations for ruptured adenomas. Indications for surgery were: symptoms in 12 cases, need to rule out malignancy in 2 cases and preoperative diagnosis of large HA in one case. Symptoms were related to bleeding in 10 cases, sepsis due to liver abscess following embolization of HA in one case and mass effect in one case (shoulder tip pain). Five cases with ruptured bleeding adenoma required emergency admission and treatment with selective arterial embolization. Laparoscopic liver resection was then semi-electively performed. Eight patients (62%) required major hepatectomy [right hepatectomy (n = 5), left hepatectomy (n = 3)]. No conversion to open surgery occurred. The median operative time for pure laparoscopic procedures was 270 min (range 135-360 min). The median size of the excised lesions was 85 mm (range 25-180 mm). One patient with adenomatosis developed postoperative bleeding requiring embolization. Mortality was nil. The median hospital stay was 4 d (range 1-18 d) with a median high dependency unit stay of 1 d (range 0-7 d). CONCLUSION: The laparoscopic approach represents a safe option for the management of HA in a semi-elective setting and when major hepatectomy is required.