Are Surgical Drains Needed in DIEP Flap Surgery? The Drain-Free DIEP Flap Concept.

BACKGROUND: Studies support an inherent morbidity associated with the use of surgical drains-such as postoperative pain, infection, reduction in mobility, and delay in patient discharge-and they do not prevent seroma or hematoma. The authors' series aims to evaluate the feasibility, benefits, and safety of performing drainless deep inferior epigastric perforator (DIEP) flap surgery and to formulate an algorithm for when this can be used. METHODS: A retrospective review of DIEP reconstruction outcomes of two surgeons was performed. Over the course of 24 months, consecutive DIEP flap patients were included from the Royal Marsden Hospital in London and Austin Hospital in Melbourne, and drain use, drain output, length of stay (LOS), and complications were analyzed. RESULTS: A total of 107 DIEP flap reconstructions were performed by two surgeons. Thirty-five patients had abdominal drainless DIEP flaps, and 12 patients had totally drainless DIEP flaps. Mean age was 52 years (range, 34 to 73 years) and mean body mass index was 26.8 kg/m 2 (range, 19.0 to 41.3 kg/m 2 ). Abdominal drainless patients showed a potential trend toward shorter hospital stays as compared with the ones with drains (mean LOS, 3.74 days versus 4.05 days; P = 0.154). Totally drainless patients had an even shorter, statistically significant, mean LOS of 3.10 days, as compared with patients with drains (4.05 days, P = 0.002), with no increase in complications. CONCLUSIONS: The avoidance of abdominal drains in DIEP flaps reduces hospital stay without increasing complications, and this has become our standard practice for patients with a body mass index of less than 30 kg/m 2 . It is our opinion that the totally drainless DIEP flap procedure is safe in selected patients. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Association between wetland presence and incidence of Salmonella enterica serotype Javiana infections in selected US sites, 2005-2011.

Salmonella causes an estimated 1·2 million illnesses annually in the USA. Salmonella enterica serotype Javiana (serotype Javiana) is the fourth most common serotype isolated from humans, with the majority of illnesses occurring in southeastern states. The percentage of wetland cover by wetland type and the average incidence rates of serotype Javiana infection in selected counties of the Foodborne Disease Active Surveillance Network (FoodNet) were examined. This analysis explored the relationship between wetland environments and incidence in order to assess whether regional differences in environmental habitats may be associated with observed variations in incidence. Findings suggest that environmental habitats may support reservoirs or contribute to the persistence of serotype Javiana, and may frequently contribute to the transmission of infection compared with other Salmonella serotypes.

Attribution of Salmonella enterica serotype Hadar infections using antimicrobial resistance data from two points in the food supply system.

A challenge to the development of foodborne illness prevention measures is determining the sources of enteric illness. Microbial subtyping source-attribution models attribute illnesses to various sources, requiring data characterizing bacterial isolate subtypes collected from human and food sources. We evaluated the use of antimicrobial resistance data on isolates of Salmonella enterica serotype Hadar, collected from ill humans, food animals, and from retail meats, in two microbial subtyping attribution models. We also compared model results when either antimicrobial resistance or pulsed-field gel electrophoresis (PFGE) patterns were used to subtype isolates. Depending on the subtyping model used, 68-96% of the human infections were attributed to meat and poultry food products. All models yielded similar outcomes, with 86% [95% confidence interval (CI) 80-91] to 91% (95% CI 88-96) of the attributable infections attributed to turkey, and 6% (95% CI 2-10) to 14% (95% CI 8-20) to chicken. Few illnesses (<3%) were attributed to cattle or swine. Results were similar whether the isolates were obtained from food animals during processing or from retail meat products. Our results support the view that microbial subtyping models are a flexible and robust approach for attributing Salmonella Hadar.

The CaSm (LSm1) oncogene promotes transformation, chemoresistance and metastasis of pancreatic cancer cells.

The cancer-associated Sm-like (CaSm) oncogene is overexpressed in 87% of human pancreatic tumor samples and CaSm knockdown has demonstrated therapeutic efficacy in murine models of pancreatic cancer. Evidence indicates that CaSm modulates messenger RNA degradation; however, its target genes and the mechanisms by which CaSm promotes pancreatic cancer remain largely unknown. Here, we demonstrate that the CaSm overexpression alters several hallmarks of cancer-including transformation, proliferation, chemoresistance and metastasis. Doxycycline-induced CaSm expression enhanced proliferation and both anchorage-dependent and -independent growth of the human Panc-1 cells in vitro. CaSm induction decreased gemcitabine-induced cytotoxicity and altered the expression of apoptotic regulation genes, including Bad, E2F1 and Bcl-XL. CaSm-overexpressing Panc-1 cells were twofold more migratory and fourfold more invasive than the driver controls and demonstrated characteristics of epithelial-to-mesenchymal transition such as morphological changes and decreased E-cadherin expression. CaSm induction resulted in changes in RNA expression of metastasis-associated genes such as MMP1, SerpinB5, uPAR and Slug. Using a murine model of metastatic pancreatic cancer, injection of CaSm-induced Panc-1 cells resulted in a higher abundance of hepatic metastatic lesions. Overall, CaSm overexpression contributed to a more aggressive cancer phenotype in Panc-1 cells, further supporting the use of CaSm as a therapeutic target against pancreatic cancer.

The rise and decline in Salmonella enterica serovar Enteritidis outbreaks attributed to egg-containing foods in the United States, 1973-2009.

Salmonella enterica causes an estimated 1 million domestically acquired foodborne illnesses annually. Salmonella enterica serovar Enteritidis (SE) is among the top three serovars of reported cases of Salmonella. We examined trends in SE foodborne outbreaks from 1973 to 2009 using Joinpoint and Poisson regression. The annual number of SE outbreaks increased sharply in the 1970s and 1980s but declined significantly after 1990. Over the study period, SE outbreaks were most frequently attributed to foods containing eggs. The average rate of SE outbreaks attributed to egg-containing foods reported by states began to decline significantly after 1990, and the proportion of SE outbreaks attributed to egg-containing foods began declining after 1997. Our results suggest that interventions initiated in the 1990s to decrease SE contamination of shell eggs may have been integral to preventing SE outbreaks.

IL-12 conditioning improves retrovirally mediated transduction efficiency of CD8+ T cells.

The ability to genetically modify T cells is a critical component to many immunotherapeutic strategies and research studies. However, the success of these approaches is often limited by transduction efficiency. As retroviral vectors require cell division for integration, transduction efficiency is dependent on the appropriate activation and culture conditions for T cells. Naive CD8(+) T cells, which are quiescent, must be first activated to induce cell division to allow genetic modification. To optimize this process, we activated mouse T cells with a panel of different cytokines, including interleukin-2 (IL-2), IL-4, IL-6, IL-7, IL-12, IL-15 and IL-23, known to act on T cells. After activation, cytokines were removed, and activated T cells were retrovirally transduced. We found that IL-12 preconditioning of mouse T cells greatly enhanced transduction efficiency, while preserving function and expansion potential. We also observed a similar transduction-enhancing effect of IL-12 preconditioning on human T cells. These findings provide a simple method to improve the transduction efficiencies of CD8(+) T cells.

Impact of intracellular domain flexibility upon properties of activated human 5-HT3 receptors.

BACKGROUND AND PURPOSE: It has been proposed that arginine residues lining the intracellular portals of the homomeric 5-HT3 A receptor cause electrostatic repulsion of cation flow, accounting for a single-channel conductance substantially lower than that of the 5-HT3 AB heteromer. However, comparison of receptor homology models for wild-type pentamers suggests that salt bridges in the intracellular domain of the homomer may impart structural rigidity, and we hypothesized that this rigidity could account for the low conductance. EXPERIMENTAL APPROACH: Mutations were introduced into the portal region of the human 5-HT3 A homopentamer, such that putative salt bridges were broken by neutralizing anionic partners. Single-channel and whole cell currents were measured in transfected tsA201 cells and in Xenopus oocytes respectively. Computational simulations of protein flexibility facilitated comparison of wild-type and mutant receptors. KEY RESULTS: Single-channel conductance was increased substantially, often to wild-type heteromeric receptor values, in most 5-HT3 A mutants. Conversely, introduction of arginine residues to the portal region of the heteromer, conjecturally creating salt bridges, decreased conductance. Gating kinetics varied significantly between different mutant receptors. EC50 values for whole-cell responses to 5-HT remained largely unchanged, but Hill coefficients for responses to 5-HT were usually significantly smaller in mutants. Computational simulations suggested increased flexibility throughout the protein structure as a consequence of mutations in the intracellular domain. CONCLUSIONS AND IMPLICATIONS: These data support a role for intracellular salt bridges in maintaining the quaternary structure of the 5-HT3 receptor and suggest a role for the intracellular domain in allosteric modulation of cooperativity and agonist efficacy.

Transferrin receptor targeting nanomedicine delivering wild-type p53 gene sensitizes pancreatic cancer to gemcitabine therapy.

To overcome gene therapy barriers such as low transfection efficiency and nonspecific delivery, liposomal nanoparticles targeted by a single-chain antibody fragment to the transferrin receptor (TfRscFv) delivering wild-type (wt) human p53 (SGT-53) were developed for tumor-specific targeting. We hypothesize that SGT-53 in combination with gemcitabine will demonstrate enhanced therapeutic benefit in an in vivo metastatic pancreatic cancer model. Intrasplenic injection of 1 × 10(6) Panc02 murine pancreatic cancer cells was used to generate in vivo hepatic metastatic tumors. Nanoparticle localization was assessed by tail vein injection of TfRscFv with fluorescently labeled oligonucleotides (6-carboxyfluorescein phosphoramidite (6FAM) ODN) imaged by Xenogen IVIS 200 scan. SGT-53 (equivalent to 30 µg of p53 intravenously) and gemcitabine (20 mg/kg intraperitoneally) alone and in combination were administered biweekly and compared with untreated mice. Survival was determined by blinded daily assessment of morbidity. Human wtp53 expression and transferrin levels in the tumors were assessed by western blot analysis. Tumor burden was quantified by liver weight. Xenogen imaging demonstrated tumor-specific uptake of TfRscFv-6FAM ODN. Exogenous human wtp53 protein was detected in the SGT-53-treated tumors compared with control. Compared with untreated mice with metastatic tumors demonstrating median survival of 20 days, SGT-53, gemcitabine and the combination demonstrated improved median survival of 29, 30 and 37 days, respectively. The combination treatment prolonged median survival when compared with single drug treatment and decreased tumor burden. The tumor targeting liposomal-based SGT-53 nanoparticle is capable of sensitizing pancreatic cancer to conventional chemotherapy in pancreatic cancer models. This approach has the potential to be translated into a new, more effective therapy for pancreatic cancer. Further optimization is ongoing, moving towards a Phase 1B/2 clinical trial.

Quantitative exposure assessment of waterfowl hunters to avian influenza viruses.

The potential for direct transmission of type A influenza viruses from wild waterfowl to humans is undefined. This study estimated exposure of hunters to avian influenza virus (AIV) resulting from direct contact with potentially infected waterfowl in Georgia (GA), Louisiana (LA) and Minnesota (MN), and demonstrated variation in the risk of exposure to AIV by hunting location and time. Hunting begins earlier in MN, starting in October, and later in GA and LA, usually starting in November. In addition, the numbers of hunters and birds harvested varies considerably in each state, with LA hosting the largest harvest in the USA Temporal effects resulted in variation of the exposure risk per hunter-day, with a higher risk associated with the earlier months of the hunting season. Exposure risk in locations varied due to AIV prevalence during each hunting season, average bird harvest per hunter-day, and ratio of juveniles/adult birds harvested (higher risk associated with higher ratios). Population risk is discussed based on the exposure risk and number of active hunters in each state per month. The risk of human exposure to AIV was also shown to be temporally distinct from the time of greatest risk of human influenza A infection during circulation of seasonal human influenza viruses, making recombination events due to co-infection unlikely.

Foodborne outbreaks of shigellosis in the USA, 1998-2008.

We examined reported outbreaks of foodborne shigellosis in the USA from 1998 to 2008 and summarized demographic and epidemiological characteristics of 120 confirmed outbreaks resulting in 6208 illnesses. Most reported foodborne shigellosis outbreaks (n = 70, 58%) and outbreak-associated illnesses (n = 3383, 54%) were restaurant-associated. The largest outbreaks were associated with commercially prepared foods distributed in multiple states and foods prepared in institutional settings. Foods commonly consumed raw were implicated in 29 (24%) outbreaks and infected food handlers in 28 (23%) outbreaks. Most outbreaks (n = 86, 72%) were caused by Shigella sonnei. Targeted efforts to reduce contamination during food handling at multiple points in the food processing and distribution system, including food preparation in restaurants and institutional settings, could prevent many foodborne disease outbreaks and outbreak-related illnesses including those due to Shigella.

A hybrid symbolic-numerical method for determining model structure.

In this article, we present a method for determining whether a model is at least locally identifiable and in the case of non-identifiable models whether any of the parameters are individually at least locally identifiable. This method combines symbolic and numeric methods to create an algorithm that is extremely accurate compared to other numeric methods and computationally inexpensive. A series of generic computational steps are developed to create a method that is ideal for practitioners to use. The algorithm is compared to symbolic methods for two capture-recapture models and a compartment model.

Carotid artery disease: stenting vs endarterectomy.

Several multicentre, randomized trials have validated the efficacy of carotid endarterectomy (CEA). Comparative randomized trials are also currently developing insight into the role of carotid angioplasty and stenting (CAS), and identifying factors for optimal patient selection. Although these interventions are aimed at embolic stroke prevention, anaesthetic management might prevent the subset of strokes that are haemodynamic in nature by maintaining tight physiological control. The perioperative risk of myocardial events is increased in this population. Hence, preoperative attention to cardiovascular disease, hypertension, renal insufficiency, and diabetes mellitus might reduce neurological and cardiovascular complications. During carotid artery cross-clamping, the risk of cerebral ischaemia can be decreased by maintaining normal to high perfusion pressure. Although there is no demonstrable advantage of a specific anaesthetic technique for patients undergoing CEA, it is imperative that cerebral blood flow is optimized, that there is minimal cardiac stress, and that anaesthetic recovery is rapid. Carotid angioplasty and stenting is performed under light sedation with antithrombotic therapy and vigilance for bradycardia and hypotension. Tight haemodynamic control remains a priority in the immediate postoperative period for both interventions.

Survey of biosecurity protocols and practices adopted by growers on commercial poultry farms in Georgia, U. S. A.

The integrated commercial poultry system is a highly connected network in which routine activities keep farms within a geographic area in constant contact. Consequently, biosecurity practices designed to minimize the transmission of infectious diseases between and within farms are an important component of modern flock health programs. A survey of Georgia poultry growers was conducted in order to assess the level of adoption of standard biosecurity measures by farm personnel and visitors. The results showed that compliance with recommended biosecurity practices did not significantly vary by company, farm size, or number of farms owned by the same grower. However, biosecurity was higher in the northern part of the state, where the density of farms is higher, and where there was an ongoing outbreak of infectious laryngotracheitis at the time of the study. The survey found that growers place more emphasis on biosecurity measures targeting farm visitors than those targeting farm personnel. Most growers reported that all visitors to the farm were required to wear shoe covers, although visitors were not typically required to park outside the farm entrance or to wash tires on their vehicles. No visitor type was reportedly excluded from poultry houses during grow out on all farms. The results highlight the need to evaluate the comparative efficacy of specific biosecurity measures in order to set priorities and attain feasible rates of implementation of targeted biosecurity practices.

Determining the parametric structure of models.

In this paper we develop a comprehensive approach to determining the parametric structure of models. This involves considering whether a model is parameter redundant or not and investigating model identifiability. The approach adopted makes use of exhaustive summaries, quantities that uniquely define the model. We review and generalise previous work on evaluating the symbolic rank of an appropriate derivative matrix to detect parameter redundancy, and then develop further tools for use within this framework, based on a matrix decomposition. Complex models, where the symbolic rank is difficult to calculate, may be simplified structurally using reparameterisation and by finding a reduced-form exhaustive summary. The approach of the paper is illustrated using examples from ecology, compartment modelling and Bayes networks. This work is topical as models in the biosciences and elsewhere are becoming increasingly complex.

Stochastic model of the potential spread of highly pathogenic avian influenza from an infected commercial broiler operation in Georgia.

The potential spread of highly pathogenic avian influenza among commercial broiler farms in Georgia, U. S. A., was mathematically modeled. The dynamics of the spread within the first infected flock were estimated using an SEIR (susceptible-exposed-infectious-recovered) deterministic model, and predicted that grower detection of flock infection is most likely 5 days after virus introduction. Off-farm spread of virus was estimated stochastically for this period, predicting a mean range of exposed farms from 0-5, depending on the density of farms in the area. Modeled off-farm spread was most frequently associated with feed trucks (highest daily probability and number of farm visits) and with company personnel or hired help (highest level of bird contact).

A large-scale clinical field study to evaluate the efficacy and safety of an oral formulation of the amino-acetonitrile derivative ( AAD ), monepantel , in sheep in New Zealand.

AIM: To evaluate the efficacy and safety of an oral formulation of the novel anthelmintic, monepantel (AAD 1566), in sheep, in comparison with some other anthelmintics currently registered in New Zealand. METHODS: A study was conducted on 18 farms located throughout the North and South Islands of New Zealand. On each farm, sheep naturally infected with the target nematodes were randomly assigned to groups, which were then treated with either monepantel, at a minimum dose rate of 2.5 mg/kg, or one of five other anthelmintics encompassing the range of single-entity and combination formulations that are commercially available in New Zealand, or left untreated as controls. Faecal samples were collected from all sheep pre-treatment (1-3 weeks before treatment), at the time of treatment, and approximately 1, 2 and 3 weeks after treatment (Days 7, 14 and 21). Faecal nematode egg counts (FEC) were measured in all samples, and the efficacy of treatments, as indicated by reductions in FEC, calculated. All sheep were inspected at least daily, to check for any adverse effects of treatment. RESULTS: On all 18 farms, on Days 7, 14 and 21 (54 test points), the efficacy of the monepantel solution was >95%. At Days 7 and 14 post-treatment, efficacies>99% were recorded in 15 flocks. At Day 21 post-treatment, efficacies>98% were recorded in 13 flocks. Monepantel was as effective, or more effective, than the registered anthelmintics with which it was compared. Moreover, it was effective against strains of nematodes resistant to one or more of the currently available broad-spectrum anthelmintics. The monepantel solution used in this study was well tolerated by the sheep, and no adverse events could be attributed to its use. CONCLUSIONS AND CLINICAL RELEVANCE: When administered as an oral formulation under field conditions, at a minimum dose rate of 2.5 mg/kg, monepantel appeared to be highly effective against all the major genera of gastrointestinal nematodes of sheep, including Haemonchus, Teladorsagia (=Ostertagia), Trichostrongylus, Cooperia, Nematodirus, Chabertia and Oesophagostomum. This included strains resistant to the currently available broad-spectrum anthelmintics. Monepantel is the first compound from the recently discovered amino-acetonitrile derivative (AAD) class of anthelmintics to be developed for use in sheep.

Loss of T cell-mediated antitumor immunity after construct-specific downregulation of retrovirally encoded T-cell receptor expression in vivo.

Adoptive T-cell therapy is clinically efficacious in the treatment of select cancers. However, it is often difficult to obtain adequate numbers of tumor-specific T cells for therapy. One method for overcoming this limitation is to generate tumor-specific T cells by retrovirally mediated T-cell-receptor (TCR) gene transfer. However, despite instances of therapeutic success, major obstacles remain, including attaining the survival of retrovirally modified T cells in vivo as well as inducing long-term and multi-gene retroviral expression. Using a murine model of adoptively transferred retrovirally modified CD8(+) T cells, where antitumor immunity was dependent on sustained, multigene expression, we found that in vitro assays are poor indicators of in vivo efficacy. Despite persisting for over 9 months in a nonlymphopenic environment, genetically modified T cells exhibited discordant retrovirally mediated gene expression in vivo not readily evident from initial in vitro assays. In particular, one of the two TCR subunit genes necessary for antigen specificity was selectively lost in vivo. As this discordant gene expression was associated with the loss of antitumor immunity, consideration of these findings may provide guidance in the design, evaluation and application of retroviral vectors for use in the treatment of cancer and other human disease.

Approximations for expected generation number.

A deterministic formula is commonly used to approximate the expected generation number of a population of growing cells. However, this can give misleading results because it does not allow for natural variation in the times that individual cells take to reproduce. Here we present more accurate approximations for both symmetric and asymmetric cell division. Based on the first two moments of the generation time distribution, these approximations are also robust. We illustrate the improved approximations using data that arise from monitoring individual yeast cells under a microscope and also demonstrate how the approximations can be used when such detailed data are not available.

New approximations to the Malthusian parameter.

Approximations to the Malthusian parameter of an age-dependent branching process are obtained in terms of the moments of the lifetime distribution, by exploiting a link with renewal theory. In several examples, the new approximations are more accurate than those currently in use, even when based on only the first two moments. The new approximations are extended to include a form of asymmetric cell division that occurs in some species of yeast. When used for inference, the new approximations are shown to have high efficiency.

Estimating the number of prions in yeast cells.

Certain yeast cells contain proteins that behave like the mammalian prion PrP and are called yeast prions. The yeast prion protein Sup35p can exist in one of two stable forms, giving rise to phenotypes [PSI(+)] and [psi(-)]. If the chemical guanidine hydrochloride (GdnHCl) is added to a culture of growing [PSI(+)] cells, the proportion of [PSI(+)] cells decreases over time. This process is called curing and is due to a failure to propagate the prion form of Sup35p. We describe how curing can be modelled, and improve upon previous models for the underlying processes of cell division and prion segregation; the new model allows for asymmetric cell division and unequal prion segregation. We conclude by outlining plans for future experimentation and modelling.