Comparative analysis of the Potter Tower and a new Track Sprayer for the application of residual sprays in the laboratory.

BACKGROUND: Efforts to evaluate the residual efficacy of new indoor residual spraying (IRS) formulations have identified limitations with the industry standard laboratory sprayer, the Potter Spray Tower (PT). Calibrating the PT can be time-consuming, and the dosing of surfaces may not be as accurate or uniform as previously assumed. METHODS: To address these limitations, the Micron Horizontal Track Sprayer with Spray Cabinet (TS) was developed to provide higher efficiency, ease of operation and deposition uniformity equal to or better than the PT. A series of studies were performed using a fluorescent tracer and three IRS formulations (Actellic® 300CS, K-Othrine WG250 and Suspend PolyZone) sprayed onto surfaces using either the PT or the TS. RESULTS: Deposition volumes could be accurately calibrated for both spray systems. However, the uniformity of spray deposits was higher for the TS compared to the PT. Less than 12% of the volume sprayed using the PT reaches the target surface, with the remaining 88% unaccounted for, presumably vented out of the fume hood or coating the internal surfaces of the tower. In contrast, the TS deposits most of the spray on the floor of the spray chamber, with the rest contained therein. The total sprayed surface area in one run of the TS is 1.2 m2, and the operational zone for spray target placement is 0.7 m2, meaning that 58% of the applied volume deposits onto the targets. The TS can treat multiple surfaces (18 standard 15 × 15 cm tiles) in a single application, whereas the PT treats one surface at a time and a maximum area of around 0.0225 m2. An assessment of the time taken to perform spraying, including the setup, calibration and cleaning, showed that the cost of application using the TS was around 25-35 × less per tile sprayed. Standard operating procedures (SOPs) for calibration and use of both the Potter Tower and Track Sprayer have been developed. CONCLUSIONS: Overall, the TS represents a significant improvement over the PT in terms of the efficiency and accuracy of IRS formulation applications onto test substrates and offers a useful additional tool for researchers and manufacturers wanting to screen new active ingredients or evaluate the efficacy of IRS or other sprayable formulations for insect control.

High Population Frequency of GNRHR p.Q106R in Malta: An Evaluation of Fertility and Hormone Profiles in Heterozygotes.

Context: The gonadotropin-releasing hormone receptor variant GNRHR p.Q106R (rs104893836) in homozygosity, compound heterozygosity, or single heterozygosity is often reported as the causative variant in idiopathic hypogonadotropic hypogonadism (IHH) patients with GnRH deficiency. Genotyping of a Maltese newborn cord-blood collection yielded a minor allele frequency (MAF) 10 times higher (MAF = 0.029; n = 493) than that of the global population (MAF = 0.003). Objective: To determine whether GNRHR p.Q106R in heterozygosity influences profiles of endogenous hormones belonging to the hypothalamic-pituitary axis and the onset of puberty and fertility in adult men (n = 739) and women (n = 239). Design Setting and Participants: Analysis of questionnaire data relating to puberty and fertility, genotyping of the GNRHR p.Q106R variant, and hormone profiling of a highly phenotyped Maltese adult cohort from the Maltese Acute Myocardial Infarction Study. Main Outcome and Results: Out of 978 adults, 43 GNRHR p.Q106R heterozygotes (26 men and 17 women) were identified. Hormone levels and fertility for all heterozygotes are within normal parameters except for TSH, which was lower in men 50 years or older. Conclusion: Hormone data and baseline fertility characteristics of GNRHR p.Q106R heterozygotes are comparable to those of homozygous wild-type individuals who have no reproductive problems. The heterozygous genotype alone does not impair the levels of investigated gonadotropins and sex steroid hormones or affect fertility. GNRHR p.Q106R heterozygotes who exhibit IHH characteristics must have at least another variant, probably in a different IHH gene, that drives pathogenicity. We also conclude that GNRHR p.Q106R is likely a founder variant due to its overrepresentation and prevalence in the island population of Malta.

The influence of the tertiary bronchi on dynamic lung deformation.

Finite element models of thoracic injury often treat the lung as a bulk homogeneous and isotropic material, which reduces the computational costs associated with such investigations. Ignoring the heterogeneous structure of the lung may be computationally expedient, but this simplification may inadvertently fail to capture the true lung strain dynamics. In the present work, a series of direct impact experiments were performed on porcine lungs, inflated to a relevant expiratory pressure, and monitored using high-speed X-ray imaging. The lungs were instrumented with radiopaque markers within the parenchyma and tertiary bronchi to monitor the resulting deformation mechanics. The deformation mechanics demonstrate a high degree of strain localization related to the structural heterogeneity of the lung. The relative motion of the tertiary bronchi was measured during the impact event, and used to estimate the parenchyma tissue strains in the inter-bronchial regions. These were shown to exceed the trans-lobe strains by a factor 3 to 5 times higher in their tensile, compressive, and shear strain responses. Our results demonstrate that the lung parenchyma and bronchial tissues form a heterogeneous structure with a substantial stiffness differential that cannot be appropriately modelled as a homogeneous and isotropic monolithic mass without loss of accuracy and predictive relevance.

Global patterns and determinants of lake macrophyte taxonomic, functional and phylogenetic beta diversity.

Documenting the patterns of biological diversity on Earth has always been a central challenge in macroecology and biogeography. However, for the diverse group of freshwater plants, such research program is still in its infancy. Here, we examined global variation in taxonomic, functional and phylogenetic beta diversity patterns of lake macrophytes using regional data from six continents. A data set of ca. 480 lake macrophyte community observations, together with climatic, geographical and environmental variables, was compiled across 16 regions worldwide. We (a) built the very first phylogeny comprising most freshwater plant lineages; (b) exploited a wide array of functional traits that are important to macrophyte autoecology or that relate to lake ecosystem functioning; (c) assessed if different large-scale beta diversity patterns show a clear latitudinal gradient from the equator to the poles using null models; and (d) employed evolutionary and regression models to first identify the degree to which the studied functional traits show a phylogenetic signal, and then to estimate community-environment relationships at multiple spatial scales. Our results supported the notion that ecological niches evolved independently of phylogeny in macrophyte lineages worldwide. We also showed that taxonomic and phylogenetic beta diversity followed the typical global trend with higher diversity in the tropics. In addition, we were able to confirm that species, multi-trait and lineage compositions were first and foremost structured by climatic conditions at relatively broad spatial scales. Perhaps more importantly, we showed that large-scale processes along latitudinal and elevational gradients have left a strong footprint in the current diversity patterns and community-environment relationships in lake macrophytes. Overall, our results stress the need for an integrative approach to macroecology, biogeography and conservation biology, combining multiple diversity facets at different spatial scales.

Global patterns in the metacommunity structuring of lake macrophytes: regional variations and driving factors.

We studied community-environment relationships of lake macrophytes at two metacommunity scales using data from 16 regions across the world. More specifically, we examined (a) whether the lake macrophyte communities respond similar to key local environmental factors, major climate variables and lake spatial locations in each of the regions (i.e., within-region approach) and (b) how well can explained variability in the community-environment relationships across multiple lake macrophyte metacommunities be accounted for by elevation range, spatial extent, latitude, longitude, and age of the oldest lake within each metacommunity (i.e., across-region approach). In the within-region approach, we employed partial redundancy analyses together with variation partitioning to investigate the relative importance of local variables, climate variables, and spatial location on lake macrophytes among the study regions. In the across-region approach, we used adjusted R2 values of the variation partitioning to model the community-environment relationships across multiple metacommunities using linear regression and commonality analysis. We found that niche filtering related to local lake-level environmental conditions was the dominant force structuring macrophytes within metacommunities. However, our results also revealed that elevation range associated with climate (increasing temperature amplitude affecting macrophytes) and spatial location (likely due to dispersal limitation) was important for macrophytes based on the findings of the across-metacommunities analysis. These findings suggest that different determinants influence macrophyte metacommunities within different regions, thus showing context dependency. Moreover, our study emphasized that the use of a single metacommunity scale gives incomplete information on the environmental features explaining variation in macrophyte communities.

The Development of a Recombinant scFv Monoclonal Antibody Targeting Canine CD20 for Use in Comparative Medicine.

Monoclonal antibodies are leading agents for therapeutic treatment of human diseases, but are limited in use by the paucity of clinically relevant models for validation. Sporadic canine tumours mimic the features of some human equivalents. Developing canine immunotherapeutics can be an approach for modeling human disease responses. Rituximab is a pioneering agent used to treat human hematological malignancies. Biologic mimics that target canine CD20 are just being developed by the biotechnology industry. Towards a comparative canine-human model system, we have developed a novel anti-CD20 monoclonal antibody (NCD1.2) that binds both human and canine CD20. NCD1.2 has a sub-nanomolar Kd as defined by an octet red binding assay. Using FACS, NCD1.2 binds to clinically derived canine cells including B-cells in peripheral blood and in different histotypes of B-cell lymphoma. Immunohistochemical staining of canine tissues indicates that the NCD1.2 binds to membrane localized cells in Diffuse Large B-cell lymphoma, Marginal Zone Lymphoma, and other canine B-cell lymphomas. We cloned the heavy and light chains of NCD1.2 from hybridomas to determine whether active scaffolds can be acquired as future biologics tools. The VH and VL genes from the hybridomas were cloned using degenerate primers and packaged as single chains (scFv) into a phage-display library. Surprisingly, we identified two scFv (scFv-3 and scFv-7) isolated from the hybridoma with bioactivity towards CD20. The two scFv had identical VH genes but different VL genes and identical CDR3s, indicating that at least two light chain mRNAs are encoded by NCD1.2 hybridoma cells. Both scFv-3 and scFv-7 were cloned into mammalian vectors for secretion in CHO cells and the antibodies were bioactive towards recombinant CD20 protein or peptide. The scFv-3 and scFv-7 were cloned into an ADEPT-CPG2 bioconjugate vector where bioactivity was retained when expressed in bacterial systems. These data identify a recombinant anti-CD20 scFv that might form a useful tool for evaluation in bioconjugate-directed anti-CD20 immunotherapies in comparative medicine.

Learning curves in abdominal wall reconstruction with components separation: one step closer toward improving outcomes and reducing complications.

INTRODUCTION: Learning curves are characterized by incremental improvement of a process, through repetition and reduction in variability, but can be disrupted with the emergence of new techniques and technologies. Abdominal wall reconstruction continues to evolve, with the introduction of components separation in the 1990s and biologic mesh in the 2000s. As such, attempts at innovation may impact the success of reconstructive outcomes and yield a changing set of complications. The purpose of this project was to describe the paradigm shift that has occurred in abdominal wall reconstruction during the past 10 years, focusing on the incorporation of new materials and methods. METHODS: We reviewed 150 consecutive patients who underwent abdominal wall reconstruction of midline defects with components separation, from 2000 to 2010. Both univariate and multivariate logistic regression analyses were performed to identify risk factors for complications. Patients were stratified into the following periods: early (2000-2003), middle (2004-2006), and late (2007-2010). RESULTS: From 2000 to 2010, we performed 150 abdominal wall reconstructions with components separation [mean age, 50.2 years; body mass index (BMI), 30.4; size of defect, 357 cm; length of stay, 9.6 days; follow-up, 4.4 years]. Primary fascial closure was performed in 120 patients. Mesh was used in 114 patients in the following locations: overlay (n = 28), inlay (n = 30), underlay (n = 54), and unknown (n = 2). Complications occurred in a bimodal distribution, highest in 2001 (introduction of biologic mesh) and 2008 (conversion from underlay to overlay location). Age, sex, history of smoking, defect size, and length of stay were not associated with incidence of complications. Unadjusted risk factors for seroma (16.8%) were elevated BMI, of previous hernia repairs, use of overlay mesh, and late portion of the learning curve, with logistic regression supporting only late portion of the learning curve [odds ratio (OR), 4.3; 95% confidence interval (CI), 1.0-18.6] and BMI (OR, 1.17; 95% CI, 1.06-1.29). The only unadjusted risk factor for recurrence was location of mesh. Logistic regression, comparing underlay, inlay, and overlay mesh to no mesh, revealed that the use of underlay mesh predicted recurrence (OR, 3.0; 95% CI, 1.04-8.64). All P values were less than 0.05. CONCLUSIONS: The overall learning curve for a specific procedure, such as abdominal wall reconstruction, can be quite volatile, especially as innovative techniques and new technologies are introduced and incorporated into the surgeon's practice. Our current practice includes primary repair myofascial flap of the components separation and the use of biologic mesh as an overlay graft, anchored to the external oblique. This process of outcome improvement is not gradual but is often punctuated by periods of failure and redemption.

Racial differences in ischemic complications of pedicled versus free abdominal flaps for breast reconstruction.

PURPOSE: This study aims to determine the relationship between race and ischemic complications in women undergoing breast reconstruction with pedicled TRAM (pTRAM) and perforator flaps (DIEP). PATIENTS AND METHODS: A retrospective, cross-sectional study of women who underwent breast reconstruction utilizing either pTRAM or DIEP flaps from March 1, 2002 to September 1, 2012 was performed. Clinical and demographic variables, including race and ischemic complications (mastectomy flap necrosis, fat necrosis, partial abdominal flap necrosis, vascular compromise requiring reoperation), were examined. Fat necrosis was graded using a previously established scale (grade I = radiologically visible, II = palpable, III = palpable and visible, IV = symptomatic). RESULTS: Over the 10-year study period, adequate follow-up was available for 138 women (94 Caucasian, 36 African American) who underwent pTRAM or DIEP. Fat necrosis occurred more frequently in the pTRAM group (53.5% vs. 17.4%, P < 0.001). There was no statistically significant difference in partial flap necrosis or mastectomy flap necrosis between the 2 groups. The DIEP group had a higher rate of vascular compromise requiring reoperation (13% vs. 0, P = 0.003). In the pTRAM group, there was a higher rate of fat necrosis (77% vs. 45.6%, P < 0.001) and grade IV fat necrosis in African Americans (42.8% vs. 9.5%, P = 0.005). Rates of other ischemic complications were comparable between the 2 racial groups. In the DIEP group, ischemic complications were comparable between the 2 racial groups. After stratifying by flap type and race, we saw no differences in mastectomy flap necrosis (P = 0.0182). DISCUSSION: African Americans undergoing pTRAM flap are at higher risk for grade IV fat necrosis but not mastectomy flap necrosis or partial flap necrosis. This may be due to difficulty using physical examination to judge the vascular status of a pedicle flap that is known to undergo significant changes in vascular physiology following transfer. Intraoperative assessment of perfusion using new technologies may be useful in these higher risk patients.

Incidence and management of adverse events after the use of laser therapies for the treatment of hypertrophic burn scars.

INTRODUCTION: Hypertrophic burn scars may generate significant morbidity, due to intense pruritus, persistent dysesthesias, and contracture. Although treatment with pulsed dye laser and fractional CO2 laser may improve symptoms, incidence of secondary wound complications is not well known. We examined the adverse event profile of laser therapies for the treatment of hypertrophic burn scars. METHODS: We performed a descriptive, retrospective, 6-month study of all patients who underwent laser therapies, at an accredited regional burn center, to improve the vascularity, texture, thickness, and stiffness of symptomatic burn scars. Data regarding skin type, mechanism, area treated, and laser parameters were collected. Main outcome measures included pigmentation changes, blistering, rash, infection. χ analysis and Student t test were used to evaluate associations between variables. RESULTS: A total of 95 patients underwent 163 treatment sessions (mean, 2.7 sessions/patient) with pulsed dye laser (71%), CO2 laser (22%), and other lasers (7%). Forty-one adverse events were recorded: hyperpigmentation (2%), hypopigmentation (12%), mild blistering (27%), pain (37%), rash (7%), fever (10%), and infection (2%). Patients with scald burns were more likely to develop blistering, rash, and fever after treatment (all P < 0.05). Higher Fitzpatrick skin type was associated with hypopigmentation and blistering, whereas CO2 laser was associated with increased postoperative pain (all P < 0.05) CONCLUSIONS: Despite the frequent occurrence of pain and mild blistering after laser treatment of hypertrophic burn scars, major adverse effects were exceedingly rare, with improvement noted in all patients. Patients with higher Fitzpatrick skin types must be handled with care, to avoid complications of blistering and hypopigmentation.

Silencing of genes and alleles by RNAi in Anopheles gambiae.

Anopheles gambiae mosquitoes are the major vectors of human malaria parasites. However, mosquitoes are not passive hosts for parasites, actively limiting their development in vivo. Our current understanding of the mosquito antiparasitic response is mostly based on the phenotypic analysis of gene knockdowns obtained by RNA interference (RNAi), through the injection or transfection of long dsRNAs in adult mosquitoes or cultured cells, respectively. Recently, RNAi has been extended to silence specifically one allele of a given gene in a heterozygous context, thus allowing to compare the contribution of different alleles to a phenotype in the same genetic background.

Once is not enough: withholding postoperative prophylactic antibiotics in prosthetic breast reconstruction is associated with an increased risk of infection.

BACKGROUND: There has been a trend toward limiting perioperative prophylactic antibiotics, based on research not conducted in plastic surgery patients. The authors' university hospital instituted antibiotic prescribing guidelines based on the Surgical Care Improvement Project. An increased rate of surgical-site infections was noted in breast reconstruction patients. The authors sought to determine whether the change in antibiotic prophylaxis regimen affected rates of surgical-site infections. METHODS: A retrospective study compared patients undergoing breast reconstruction who received preoperative and postoperative prophylactic antibiotics with a group who received only a single dose of preoperative antibiotic. Type of reconstruction and known risk factors for implant infection were noted. RESULTS: Two hundred fifty patients were included: 116 in the pre-Surgical Care Improvement Project group and 134 in the Surgical Care Improvement Project group. The overall rate of surgical-site infections increased from 18.1 percent to 34.3 percent (p = 0.004). Infections requiring reoperation increased from 4.3 percent to 16.4 percent (p = 0.002). Multivariate logistic regression demonstrated that patients in the Surgical Care Improvement group were 4.74 times more likely to develop a surgical-site infection requiring reoperation (95 percent CI, 1.69 to 13.80). Obesity, history of radiation therapy, and reconstruction with tissue expanders were associated with increased rates of surgical-site infection requiring reoperation. CONCLUSIONS: Withholding postoperative prophylactic antibiotics in prosthetic breast reconstruction is associated with an increased risk of surgical-site infection, reoperation, and thus reconstructive failure. The optimal duration of postoperative prophylactic antibiotic use is the subject of future study.

Risk factors for cervical spine injury.

INTRODUCTION: The early recognition of cervical spine injury remains a top priority of acute trauma care. Missed diagnoses can lead to exacerbation of an existing injury and potentially devastating consequences. We sought to identify predictors of cervical spine injury. METHODS: Trauma registry records for blunt trauma patients cared for at a Level I Trauma Centre from 1997 to 2002 were examined. Cervical spine injury included all cervical dislocations, fractures, fractures with spinal cord injury, and isolated spinal cord injuries. Univariate and adjusted odds ratios (ORs) were calculated to identify potential risk factors. Variables and two-way interaction terms were subjected to multivariate analysis using backward conditional stepwise logistic regression. RESULTS: Data from 18,644 patients, with 55,609 injuries, were examined. A total of 1255 individuals (6.7%) had cervical spine injuries. Motor Vehicle Collision (MVC) (odds ratio (OR) of 1.61 (1.26, 2.06)), fall (OR of 2.14 (1.63, 2.79)), age <40 (OR of 1.75 (1.38-2.17)), pelvic fracture (OR of 9.18 (6.96, 12.11)), Injury Severity Score (ISS) >15 (OR of 7.55 (6.16-9.25)), were all significant individual predictors of cervical spine injury. Neither facial fracture nor head injury alone were associated with an increased risk of cervical spine injury. Significant interactions between pelvic fracture and fall and pelvic fracture and head injury were associated with a markedly increased risk of cervical spine (OR 19.6 (13.1, 28.8)) and (OR 27.2 (10.0-51.3)). CONCLUSIONS: MVC and falls were independently associated with cervical spine injury. Pelvic fracture and fall and pelvic fracture and head injury, had a greater than multiplicative interaction and high risk for cervical spine injury, warranting increased vigilance in the evaluation of patients with this combination of injuries.

The volume-outcome relationship for immediate breast reconstruction.

BACKGROUND: Efforts to improve the quality of surgical care in the United States have led many organizations to advocate the use of high-volume hospitals for complex surgical procedures and/or comprehensive multidisciplinary care. The benefits, if any, of selective referral to high-volume hospitals for immediate breast reconstruction are relatively unknown. It is this gap in knowledge that forms the basis for the current study. METHODS: Using California's Office of Statewide Health Planning and Development discharge database, all patients undergoing immediate breast reconstruction from January 1, 1998, to December 31, 1999, were identified. Information regarding demographic, comorbidity, complication, and hospital volume characteristics was obtained. Patient comorbidity was graded using a modified version of the Charlson score. Annual hospital volume was categorized into patient quartiles. Multivariate logistic regression was performed to identify predictors of surgical complications. RESULTS: A total of 2691 patients were included: 1271 had immediate autogenous tissue reconstruction and 1420 had immediate tissue expander placement. The complication rate was 11.6 percent among patients undergoing autogenous reconstruction and 2.4 percent among patients receiving tissue expanders. For autogenous reconstruction, complications were more likely in patients with comorbidities (odds ratio, 2.24) and in patients receiving care at very-low-volume (less than eight) and medium-volume (20 to 41) hospitals (odds ratio,1.81 and 1.90, respectively). For tissue expander reconstruction, patient comorbidity (odds ratio, 2.42) was the only significant predictor of complications. CONCLUSIONS: Hospital volume appears to be an important predictor of patient outcome with regard to autogenous reconstruction but not tissue expander reconstruction. Patient comorbidity predicts complications for both autogenous and tissue expander reconstruction. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, III.

Comparison of implant-based immediate breast reconstruction with and without acellular dermal matrix.

BACKGROUND: Acellular dermal matrix is frequently used in implant-based breast reconstruction to cover the inferior aspect of the breast pocket. Its performance profile remains equivocal. The authors studied whether adding it in implant-based immediate breast reconstruction improved outcomes when compared with non-acellular dermal matrix reconstruction. METHODS: Patients undergoing implant-based immediate breast reconstruction at a single academic medical center were evaluated. Aesthetic outcomes and postoperative complications were assessed and direct comparisons were made between acellular dermal matrix and non-acellular dermal matrix cohorts. RESULTS: A total of 203 patients underwent 337 immediate expander-based breast reconstructions [with acellular dermal matrix, n=208 (61.7 percent); without, n=129 (38.3 percent)]. Patient characteristics, including age at time of reconstruction (mean, 49±11 versus 47±10 years) and body mass index (mean, 23±5 versus 23±3 kg/m) were similar between groups (p>0.05). Complications occurred in one-third of patients (33.5 percent). In univariate analyses, acellular dermal matrix use had fewer overall complications (odds ratio, 0.61; 95 percent CI, 0.38 to 0.97). The incidences of seroma/hematoma (p=0.59), infection (p=0.31), and wound complications (p=0.26) did not differ. Aesthetic outcomes were higher in the acellular dermal matrix group. In multivariate logistic regression, acellular dermal matrix use was associated with less capsular contracture (odds ratio, 0.18; 95 percent CI, 0.08 to 0.43) and mechanical shift (odds ratio, 0.23; 95 percent CI, 0.06 to 0.78). CONCLUSIONS: Optimizing the inframammary fold with acellular dermal matrix creates a superior aesthetic result. Its use appears safe and is associated with less capsular contracture and mechanical shift and improvement in the inframammary fold appearance, without increasing postoperative complications. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Pulse-dose application of chelated copper to a river for Didymosphenia geminata control: effects on macroinvertebrates and fish.

A 1-h pulse-dose of a chelated Cu formulation (Gemex™; New Zealand) was applied to a river to test efficacy against the invasive mat-forming diatom Didymosphenia geminata (didymo) and to provide information on nontarget species effects that could not be adequately predicted from laboratory and experimental mesocosm studies. Intensive sampling allowed characterization of doses achieved at multiple downstream locations, and concurrent application of rhodamine dye allowed quantification of dispersion, adsorption, and dilution processes. The target dose of 10 to 20 mg Cu/L for 60 min was achieved at least 0.9 km downstream at sites with contrasting levels of didymo mat development. Adsorptive losses of Gemex were 12%/km where didymo was mostly nonvisible and approximately 36%/km where substantial didymo mats were present. At 0.9 km downstream, Cu concentrations peaked at 12 mg/L, and didymo was <5% viable (down from 65-72%) for ≥21 d posttreatment. Viability data indicate that elimination of nonvisible infestations is possible and that suppression of early-stage infestations (≤40% cover, ≤4.5 mm thick) could be achieved after repeated applications. After a single Gemex application, no significant accumulation of Cu was noted in the sediments six weeks posttreatment, but Cu concentrations remained high in algal mats (109-367 mg/kg dry wt). Long-term effects on the nontarget algal, invertebrate, or fish communities were minimal, although significant localized trout mortalities, not predicted by prior laboratory exposures, occurred on the treatment day. Extended Gemex exposure in low-hardness waters might have caused the mortalities, although changes in chelated Cu speciation also possibly contributed. The present study integrates effects on resident biota with dosage data, including changes in pH, in a natural waterway.

Invasion strategies in clonal aquatic plants: are phenotypic differences caused by phenotypic plasticity or local adaptation?

BACKGROUND AND AIMS: The successful spread of invasive plants in new environments is often linked to multiple introductions and a diverse gene pool that facilitates local adaptation to variable environmental conditions. For clonal plants, however, phenotypic plasticity may be equally important. Here the primary adaptive strategy in three non-native, clonally reproducing macrophytes (Egeria densa, Elodea canadensis and Lagarosiphon major) in New Zealand freshwaters were examined and an attempt was made to link observed differences in plant morphology to local variation in habitat conditions. METHODS: Field populations with a large phenotypic variety were sampled in a range of lakes and streams with different chemical and physical properties. The phenotypic plasticity of the species before and after cultivation was studied in a common garden growth experiment, and the genetic diversity of these same populations was also quantified. KEY RESULTS: For all three species, greater variation in plant characteristics was found before they were grown in standardized conditions. Moreover, field populations displayed remarkably little genetic variation and there was little interaction between habitat conditions and plant morphological characteristics. CONCLUSIONS: The results indicate that at the current stage of spread into New Zealand, the primary adaptive strategy of these three invasive macrophytes is phenotypic plasticity. However, while limited, the possibility that genetic diversity between populations may facilitate ecotypic differentiation in the future cannot be excluded. These results thus indicate that invasive clonal aquatic plants adapt to new introduced areas by phenotypic plasticity. Inorganic carbon, nitrogen and phosphorous were important in controlling plant size of E. canadensis and L. major, but no other relationships between plant characteristics and habitat conditions were apparent. This implies that within-species differences in plant size can be explained by local nutrient conditions. All together this strongly suggests that invasive clonal aquatic plants adapt to a wide range of habitats in introduced areas by phenotypic plasticity rather than local adaptation.

Genetic diversity in three invasive clonal aquatic species in New Zealand.

BACKGROUND: Elodea canadensis, Egeria densa and Lagarosiphon major are dioecious clonal species which are invasive in New Zealand and other regions. Unlike many other invasive species, the genetic variation in New Zealand is very limited. Clonal reproduction is often considered an evolutionary dead end, even though a certain amount of genetic divergence may arise due to somatic mutations. The successful growth and establishment of invasive clonal species may be explained not by adaptability but by pre-existing ecological traits that prove advantageous in the new environment. We studied the genetic diversity and population structure in the North Island of New Zealand using AFLPs and related the findings to the number of introductions and the evolution that has occurred in the introduced area. RESULTS: Low levels of genetic diversity were found in all three species and appeared to be due to highly homogeneous founding gene pools. Elodea canadensis was introduced in 1868, and its populations showed more genetic structure than those of the more recently introduced of E. densa (1946) and L. major (1950). Elodea canadensis and L. major, however, had similar phylogeographic patterns, in spite of the difference in time since introduction. CONCLUSIONS: The presence of a certain level of geographically correlated genetic structure in the absence of sexual reproduction, and in spite of random human dispersal of vegetative propagules, can be reasonably attributed to post-dispersal somatic mutations. Direct evidence of such evolutionary events is, however, still insufficient.

Risk factors for recurrence after repair of enterocutaneous fistula.

OBJECTIVES: To assess outcomes after repair of enterocutaneous fistulae (ECF) and identify factors that predict mortality and recurrence. DESIGN: Retrospective study. SETTING: University hospital. PATIENTS: One hundred thirty-five patients undergoing ECF repair between 1989 and 2005. MAIN OUTCOME MEASURES: Mortality and recurrence of ECF. RESULTS: Definitive operation for ECF was attempted in 135 patients. Mortality was 8%, recurrence was 17%, and 84% of patients eventually survived with a closed fistula. The primary determinant of mortality was ECF recurrence (odds ratio [OR], 6.7; 95% confidence interval [CI], 1.9-23.4). Factors independently associated with ECF recurrence by multivariate logistic regression included the presence of inflammatory bowel disease (OR, 4.9; 95% CI, 1.5-16.1), interval between diagnosis and operation of 36 weeks or longer (OR, 5.4; 95% CI, 1.8-16.4), location of fistulae in the small intestine (OR, 9.8; 95% CI, 1.7-57.6), and resection with stapled anastomosis (OR, 4.1; 95% CI, 1.3-13.2). Recurrence of ECF was 35% with resection and stapled anastomosis, 22% with simple oversew, and 11% with resection and hand-sewn anastomosis. Recurrence of ECF was 12% when operation was performed prior to 36 weeks from diagnosis, compared with 36% if performed at or beyond 36 weeks. CONCLUSIONS: The primary determinant of mortality after ECF repair is a failed operation leading to recurrence of the fistula. Risk factors for ECF recurrence include inflammatory bowel disease, fistula located in the small intestine, an interval of 36 weeks or longer between diagnosis and operation, and resection with stapled anastomosis.