Consistent metacommunity structure despite inconsistent drivers of assembly at the continental scale.

A fundamental goal of community ecology is to understand the drivers of community assembly and diversity. Local factors acting on community assembly are typically related to environmental conditions while regional factors are typically related to dispersal. Previous research has not consistently demonstrated the importance of local or regional factors, but this is likely because these factors act in concert and not in isolation. Studies that simultaneously integrate local and regional factors into analyses of community assembly can be a useful avenue to further our understanding of this core concept in community ecology. Here, we aimed to identify metacommunity structure and diversity and the local and regional drivers of community assembly at the continental scale. We evaluated metacommunity structure and drivers of assembly of macroinvertebrate communities in 941 rivers and streams nested within nine ecoregions distributed across the conterminous United States. Pattern-based metacommunity analyses and boosted regression tree techniques were used to (a) assign metacommunity structures and (b) identify the environmental, landscape and network drivers of assembly. We also evaluated how biodiversity scaled across hierarchical levels and varied among ecoregions. Metacommunity structures were consistent for the conterminous United States and each of the nine ecoregion subsets, with each ecoregional metacommunity displaying a Clementsian structure. Environmental variables were the predominant drivers of assembly, suggesting the importance of species sorting and environmental filtering on community structure; however, the identity of the most influential environmental variables differed among ecoregions and suggested hierarchical filtering on assembly. Partitioned diversity was found to be lower at the local and ecoregional levels, but turnover in diversity among ecoregions was higher than expected. Our results demonstrate contingencies in community assembly, notwithstanding consistency in metacommunity structure and support the importance of environmental control over community assembly and biodiversity. Moreover, biodiversity at the continental scale is likely maintained through this inherent variation in the drivers of assembly and concomitant changes in community composition among ecoregions. We suggest that further work should evaluate the assembly of other facets of community structure and the underlying mechanisms of the contingency in assembly drivers.

Should the laparoscopic approach be the norm for appendicectomy in the third trimester of pregnancy?

Our case describes a pregnant woman with acute appendicitis who presented in the third trimester and underwent a laparoscopic appendicectomy. She made a rapid postoperative recovery and the pregnancy was otherwise uncomplicated, ending with a spontaneous vaginal birth at 41 weeks. The diagnosis of acute appendicitis can be unclear in pregnancy. Difficulty in establishing diagnosis due to atypical presentation often leads to delay in surgery, resulting in significant maternal and fetal morbidity and mortality. Surgical intervention should be prompt in cases of suspected appendicitis and the laparoscopic approach is advocated in the first two trimesters. In the third trimester (after 28 weeks), laparotomy is often performed due to the size of the uterus and the theoretical risk of inadvertent perforation with trocar placement. More recently, several authors have described successful outcomes following laparoscopic appendicectomy after 28 weeks and with increasing reassuring data, we suggest that this minimally invasive approach should be considered in managing appendicitis in the third trimester.

Brief Report: Human Perivascular Stem Cells and Nel-Like Protein-1 Synergistically Enhance Spinal Fusion in Osteoporotic Rats.

Autologous bone grafts (ABGs) are considered as the gold standard for spinal fusion. However, osteoporotic patients are poor candidates for ABGs due to limited osteogenic stem cell numbers and function of the bone microenvironment. There is a need for stem cell-based spinal fusion of proven efficacy under either osteoporotic or nonosteoporotic conditions. The purpose of this study is to determine the efficacy of human perivascular stem cells (hPSCs), a population of mesenchymal stem cells isolated from adipose tissue, in the presence and absence of NELL-1, an osteogenic protein, for spinal fusion in the osteoporosis. Osteogenic differentiation of hPSCs with and without NELL-1 was tested in vitro. The results indicated that NELL-1 significantly increased the osteogenic potential of hPSCs in both osteoporotic and nonosteoporotic donors. Next, spinal fusion was performed by implanting scaffolds with regular or high doses of hPSCs, with or without NELL-1 in ovariectomized rats (n = 41). Regular doses of hPSCs or NELL-1 achieved the fusion rates of only 20%-37.5% by manual palpation. These regular doses had previously been shown to be effective in nonosteoporotic rat spinal fusion. Remarkably, the high dose of hPSCs+NELL-1 significantly improved the fusion rates among osteoporotic rats up to approximately 83.3%. Microcomputed tomography imaging and quantification further confirmed solid bony fusion with high dose hPSCs+NELL-1. Finally, histologically, direct in situ involvement of hPSCs in ossification was shown using undecalcified samples. To conclude, hPSCs combined with NELL-1 synergistically enhances spinal fusion in osteoporotic rats and has great potential as a novel therapeutic strategy for osteoporotic patients.

Human perivascular stem cell-based bone graft substitute induces rat spinal fusion.

Adipose tissue is an attractive source of mesenchymal stem cells (MSCs) because of its abundance and accessibility. We have previously defined a population of native MSCs termed perivascular stem cells (PSCs), purified from diverse human tissues, including adipose tissue. Human PSCs (hPSCs) are a bipartite cell population composed of pericytes (CD146+CD34-CD45-) and adventitial cells (CD146-CD34+CD45-), isolated by fluorescence-activated cell sorting and with properties identical to those of culture identified MSCs. Our previous studies showed that hPSCs exhibit improved bone formation compared with a sample-matched unpurified population (termed stromal vascular fraction); however, it is not known whether hPSCs would be efficacious in a spinal fusion model. To investigate, we evaluated the osteogenic potential of freshly sorted hPSCs without culture expansion and differentiation in a rat model of posterolateral lumbar spinal fusion. We compared increasing dosages of implanted hPSCs to assess for dose-dependent efficacy. All hPSC treatment groups induced successful spinal fusion, assessed by manual palpation and microcomputed tomography. Computerized biomechanical simulation (finite element analysis) further demonstrated bone fusion with hPSC treatment. Histological analyses showed robust endochondral ossification in hPSC-treated samples. Finally, we confirmed that implanted hPSCs indeed differentiated into osteoblasts and osteocytes; however, the majority of the new bone formation was of host origin. These results suggest that implanted hPSCs positively regulate bone formation via direct and paracrine mechanisms. In summary, hPSCs are a readily available MSC population that effectively forms bone without requirements for culture or predifferentiation. Thus, hPSC-based products show promise for future efforts in clinical bone regeneration and repair.

One-Stage Augmentation Mastopexy: A Review of 1192 Simultaneous Breast Augmentation and Mastopexy Procedures in 615 Consecutive Patients.

BACKGROUND: Despite the increasing popularity of the combined augmentation mastopexy procedure among patients, the safety and efficacy of this surgery have been questioned by many surgeons. OBJECTIVE: The authors investigated the safety and efficacy of the combined augmentation mastopexy procedure. METHODS: The authors retrospectively reviewed the medical records of 615 consecutive patients who underwent combined augmentation mastopexy procedures at a single outpatient surgery center from 1992 through 2011. Patient demographics, operative and implant details, and long-term outcomes were analyzed. Rates of complications and revisions were calculated. RESULTS: The most common complications were poor scarring (5.7%), wound-healing problems (2.9%), and deflation of saline implants (2.4%). Of the 615 patients evaluated, 104 (16.9%) elected to undergo revision surgery: 54 revision procedures were secondary to implant-related complications, and 50 were secondary to tissue-related complications. Our data compare favorably with previously reported revision rates for breast augmentation alone and mastopexy alone. CONCLUSIONS: With a skilled surgeon and proper patient selection, the combined augmentation mastopexy procedure can be safe and effective. LEVEL OF EVIDENCE: 4.

Restoration and recognition of distant, blurry irises.

Raw iris images collected outdoors at standoff distances exceeding 25 m are susceptible to noise and atmospheric blur and even under ideal imaging conditions are too degraded to carry out recognition with high accuracy. Traditionally, atmospherically distorted images have been corrected through the use of unique hardware components such as adaptive optics. Here we apply a pure digital image restoration approach to correct for optical aberrations. Image restoration was applied to both single images and image sequences. We propose both a single-frame denoising and deblurring approach, and a multiframe fusion and deblurring approach. To compare performance of the proposed methods, iris recognitions were carried out using the approach of Daugman. Hamming distances (HDs) of computed binary iris codes were measured before and after the restoration. We found the HD decreased from >0.46 prior to a mean value of <0.39 for random single images. The multiframe fusion approach produced the most robust restoration and achieved a mean HD for all subjects in our data set of 0.33 while known false matches remained at 0.44. These results show that, when used properly, image restoration approaches do significantly increase recognition performance for known true positives with low increase in false positive detections, and irises can be recognized in turbulent atmospheric conditions.

Human perivascular stem cells show enhanced osteogenesis and vasculogenesis with Nel-like molecule I protein.

An ideal mesenchymal stem cell (MSC) source for bone tissue engineering has yet to be identified. Such an MSC population would be easily harvested in abundance, with minimal morbidity and with high purity. Our laboratories have identified perivascular stem cells (PSCs) as a candidate cell source. PSCs are readily isolatable through fluorescent-activated cell sorting from adipose tissue and have been previously shown to be indistinguishable from MSCs in the phenotype and differentiation potential. PSCs consist of two distinct cell populations: (1) pericytes (CD146+, CD34-, and CD45-), which surround capillaries and microvessels, and (2) adventitial cells (CD146-, CD34+, and CD45-), found within the tunica adventitia of large arteries and veins. We previously demonstrated the osteogenic potential of pericytes by examining pericytes derived from the human fetal pancreas, and illustrated their in vivo trophic and angiogenic effects. In the present study, we used an intramuscular ectopic bone model to develop the translational potential of our original findings using PSCs (as a combination of pericytes and adventitial cells) from human white adipose tissue. We evaluated human PSC (hPSC)-mediated bone formation and vascularization in vivo. We also examined the effects of hPSCs when combined with the novel craniosynostosis-associated protein, Nel-like molecule I (NELL-1). Implants consisting of the demineralized bone matrix putty combined with NELL-1 (3 µg/µL), hPSC (2.5×10(5) cells), or hPSC+NELL-1, were inserted in the bicep femoris of SCID mice. Bone growth was evaluated using microcomputed tomography, histology, and immunohistochemistry over 4 weeks. Results demonstrated the osteogenic potential of hPSCs and the additive effect of hPSC+NELL-1 on bone formation and vasculogenesis. Comparable osteogenesis was observed with NELL-1 as compared to the more commonly used bone morphogenetic protein-2. Next, hPSCs induced greater implant vascularization than the unsorted stromal vascular fraction from patient-matched samples. Finally, we observed an additive effect on implant vascularization with hPSC+NELL-1 by histomorphometry and immunohistochemistry, accompanied by in vitro elaboration of vasculogenic growth factors. These findings hold significant implications for the cell/protein combination therapy hPSC+NELL-1 in the development of strategies for vascularized bone regeneration.

Epidemiological study of provision of cholecystectomy in England from 2000 to 2009: retrospective analysis of Hospital Episode Statistics.

BACKGROUND: The aim of this study was to report the trends in provision of cholecystectomy in the National Health System in England over the 9 year period from 2000 to 2009 and to determine the major risk factors associated with subsequent poor outcome. METHODS: The Hospital Episode Statistics database was interrogated to identify all cholecystectomy procedures for biliary stone disease in adult patients (>16 years). Multivariate regression analyses were used to identify independent predictors of in-patient death, 1 year death, conversion to open, major bile duct injury (BDI) requiring operative repair, and length of stay. RESULTS: A total of 418,214 cholecystectomy procedures for biliary stone disease were identified. Laparoscopic surgery was used in 348,311 (83.3%) cases and increased by 14.6% over the study period. The in-patient mortality rate (0.2%), 1 year mortality rate (1%), proportion of cases converted to open (5.0%), major BDI rate (0.4%), and mean length of stay (3 days) all decreased over the study period. 52,242 (12.5%) cases were carried out during an emergency admission and uptake has remained stable over the decade. Emergency surgery was more likely to be performed at high-volume centres (odds ratio [OR] 1.39, 95% confidence interval [CI] 1.35-1.44) and specialist units (OR 1.32, 95% CI 1.30-1.35). High-volume centres were more likely to complete emergency cases laparoscopically (OR 1.11, 95% CI 1.05-1.18). Multivariate regression analysis demonstrated that patient- (male gender, increasing age, and comorbidity) and disease-specific (inflammatory pathology and emergency admission) factors rather than hospital institutional characteristics (annual cholecystectomy volume and presence of specialist surgical units) were associated with poorer outcomes. CONCLUSIONS: The provision of laparoscopic cholecystectomy in England has increased. This has been associated with improvements in outcomes such as mortality and length of stay. However, emergency cholecystectomy uptake remains sub-optimal and is more likely to be performed at high-volume or specialist hospitals without adverse outcomes. Further research into the routine provision of emergency cholecystectomy in England is needed in order to optimize patient outcomes.

Perivascular stem cells: a prospectively purified mesenchymal stem cell population for bone tissue engineering.

Adipose tissue is an ideal source of mesenchymal stem cells for bone tissue engineering: it is largely dispensable and readily accessible with minimal morbidity. However, the stromal vascular fraction (SVF) of adipose tissue is a heterogeneous cell population, which leads to unreliable bone formation. In the present study, we prospectively purified human perivascular stem cells (PSCs) from adipose tissue and compared their bone-forming capacity with that of traditionally derived SVF. PSCs are a population (sorted by fluorescence-activated cell sorting) of pericytes (CD146+CD34-CD45-) and adventitial cells (CD146-CD34+CD45-), each of which we have previously reported to have properties of mesenchymal stem cells. Here, we found that PSCs underwent osteogenic differentiation in vitro and formed bone after intramuscular implantation without the need for predifferentiation. We next sought to optimize PSCs for in vivo bone formation, adopting a demineralized bone matrix for osteoinduction and tricalcium phosphate particle formulation for protein release. Patient-matched, purified PSCs formed significantly more bone in comparison with traditionally derived SVF by all parameters. Recombinant bone morphogenetic protein 2 increased in vivo bone formation but with a massive adipogenic response. In contrast, recombinant Nel-like molecule 1 (NELL-1; a novel osteoinductive growth factor) selectively enhanced bone formation. These studies suggest that adipose-derived human PSCs are a new cell source for future efforts in skeletal regenerative medicine. Moreover, PSCs are a stem cell-based therapeutic that is readily approvable by the U.S. Food and Drug Administration, with potentially increased safety, purity, identity, potency, and efficacy. Finally, NELL-1 is a candidate growth factor able to induce human PSC osteogenesis.

An abundant perivascular source of stem cells for bone tissue engineering.

Adipose tissue is an ideal mesenchymal stem cell (MSC) source, as it is dispensable and accessible with minimal morbidity. However, the stromal vascular fraction (SVF) of adipose tissue is a heterogeneous cell population, which has disadvantages for tissue regeneration. In the present study, we prospectively purified human perivascular stem cells (PSCs) from n = 60 samples of human lipoaspirate and documented their frequency, viability, and variation with patient demographics. PSCs are a fluorescence-activated cell sorting-sorted population composed of pericytes (CD45-, CD146+, CD34-) and adventitial cells (CD45-, CD146-, CD34+), each of which we have previously reported to have properties of MSCs. Here, we found that PSCs make up, on average, 43.2% of SVF from human lipoaspirate (19.5% pericytes and 23.8% adventitial cells). These numbers were minimally changed by age, gender, or body mass index of the patient or by length of refrigerated storage time between liposuction and processing. In a previous publication, we observed that human PSCs (hPSCs) formed significantly more bone in vivo in comparison with unsorted human SVF (hSVF) in an intramuscular implantation model. We now extend this finding to a bone injury model, observing that purified hPSCs led to significantly greater healing of mouse critical-size calvarial defects than hSVF (60.9% healing as opposed to 15.4% healing at 2 weeks postoperative by microcomputed tomography analysis). These studies suggest that adipose-derived hPSCs are a new cell source for future efforts in skeletal regenerative medicine. Moreover, hPSCs are a stem cell-based therapeutic that is readily approvable by the U.S. Food and Drug Administration, with potentially increased safety, purity, identity, potency, and efficacy.

Additive effects of sonic hedgehog and Nell-1 signaling in osteogenic versus adipogenic differentiation of human adipose-derived stromal cells.

A theoretical inverse relationship exists between osteogenic (bone forming) and adipogenic (fat forming) mesenchymal stem cell (MSC) differentiation. This inverse relationship in theory partially underlies the clinical entity of osteoporosis, in which marrow MSCs have a preference for adipose differentiation that increases with age. Two pro-osteogenic cytokines have been recently studied that each also possesses antiadipogenic properties: Sonic Hedgehog (SHH) and NELL-1 proteins. In the present study, we assayed the potential additive effects of the biologically active N-terminus of SHH (SHH-N) and NELL-1 protein on osteogenic and adipogenic differentiation of human primary adipose-derived stromal cell (hASCs). We observed that both recombinant SHH-N and NELL-1 protein significantly enhanced osteogenic differentiation and reduced adipose differentiation across all markers examined (alkaline phosphatase, Alizarin red and Oil red O staining, and osteogenic gene expression). Moreover, SHH-N and NELL-1 directed signaling produced additive effects on the pro-osteogenic and antiadipogenic differentiation of hASCs. NELL-1 treatment increased Hedgehog signaling pathway expression; coapplication of the Smoothened antagonist Cyclopamine reversed the pro-osteogenic effect of NELL-1. In summary, Hedgehog and Nell-1 signaling exert additive effects on the pro-osteogenic and antiadipogenic differentiation of ASCs. These studies suggest that the combination cytokines SHH-N+NELL-1 may represent a viable future technique for inducing the osteogenic differentiation of MSCs.

The role of integrated F-18-FDG-PET scanning in the detection of M1 disease in oesophageal adenocarcinoma and impact on clinical management.

INTRODUCTION: The aim of this study was to evaluate the efficacy of F-18-fluorodeoxyglucose positron emission tomography (FDG-PET) scanning in the staging of oesophageal adenocarcinoma. METHODS: One hundred four patients with biopsy-proven adenocarcinoma underwent (18)F-FDG-PET scan. FDG avid lesions were further investigated to their diagnostic conclusion. RESULTS: Nineteen patients (18.26%) were found to have non-loco-regional FDG uptake. Of the patients, 3.84% were found to have M1 disease and 7.69% were found to have a second primary tumour. The sensitivity and specificity of FDG-PET scanning to detect metastatic disease in our series was 57.14% and 84.53%, respectively. The overall diagnostic accuracy was 82.69%. CONCLUSIONS: PET scanning improves staging and prevents unnecessary surgery in patients with M1 disease. It represents a good adjunct to computed tomography scanning and endoscopic ultrasound in the staging of oesophageal adenocarcinoma. The detection of asymptomatic coexisting synchronous cancers is an added benefit provided by PET scanning over similar diagnostic modalities.

Consenting practice for laparoscopic cholecystectomy - are we doing enough to warn patients about their operation?

INTRODUCTION: Provision of informed consent prior to surgery is fundamental in allowing patients to make balanced choices about their care. This study compares consenting practice amongst different grade of surgeons for Laparoscopic Cholecystectomy (LC) with specific reference to the documentation of the complications of surgery. Timing and delivery of source of information is also evaluated. METHODS: Retrospective review of medical notes of all patients undergoing LC at London district general hospital between September 2006 to April 2009. RESULTS: Records were successfully retrieved for 163 patients. The five most commonly mentioned complications were bleeding (99%), infection (95%), conversion to open (93%), bile duct injury (82%) and visceral injury (65%). There were 27 documented complications in 23 patients and in 9 of these patients (39%) the specific complication was not discussed during the written consent process. Consultant surgeons tended to focus on important operation-specific risks such as bile duct injury whereas junior surgeons tend to focus on a broad range of general complications. CONCLUSION: Consenting practice for LC remains variable and is resulting in failure to warn patients of significant complications. This can lead to potential medico-legal implications. Having a structured consent form detailing all significant and common risk is one way of improving the consent process.

The clonal origins of dysplasia from intestinal metaplasia in the human stomach.

BACKGROUND & AIMS: Studies of the clonal architecture of gastric glands with intestinal metaplasia are important in our understanding of the progression from metaplasia to dysplasia. It is not clear if dysplasias are derived from intestinal metaplasia or how dysplasias expand. We investigated whether cells within a metaplastic gland share a common origin, whether glands clonally expand by fission, and determine if such metaplastic glands are genetically related to the associated dysplasia. We also examined the clonal architecture of entire dysplastic lesions and the genetic changes associated with progression within dysplasia. METHODS: Cytochrome c oxidase-deficient (CCO⁻) metaplastic glands were identified using a dual enzyme histochemical assay. Clonality was assessed by laser capture of multiple cells throughout CCO⁻ glands and polymerase chain reaction sequencing of the entire mitochondrial DNA (mtDNA) genome. Nuclear DNA abnormalities in individual glands were identified by laser capture microdissection polymerase chain reaction sequencing for mutation hot spots and microsatellite loss of heterozygosity analysis. RESULTS: Metaplastic glands were derived from the same clone-all lineages shared a common mtDNA mutation. Mutated glands were found in patches that had developed through gland fission. Metaplastic and dysplastic glands can be genetically related, indicating the clonal origin of dysplasia from metaplasia. Entire dysplastic fields contained a founder mutation from which multiple, distinct subclones developed. CONCLUSIONS: There is evidence for a distinct clonal evolution from metaplasia to dysplasia in the human stomach. By field cancerization, a single clone can expand to form an entire dysplastic lesion. Over time, this field appears to become genetically diverse, indicating that gastric cancer can arise from a subclone of the founder mutation.

Malignant gastro-colic fistula presenting with upper extremity deep vein thrombosis.

Locally invasive colonic carcinomas are seldom complicated by the formation of gastro-colic fistula. The authors present a case of a 52-year-old man with malignant gastro-colic fistula presenting with upper extremity deep vein thrombosis posing operative challenges.

Safe and consistent outcomes of successfully combining breast surgery and abdominoplasty: an update.

BACKGROUND: Combined cosmetic procedures have become increasingly popular. One of the most common combinations of cosmetic procedures includes abdominoplasty and cosmetic breast surgery. The shortened recovery and financial savings associated with combined surgery contribute to the increased demand for these combined surgeries. OBJECTIVE: The goal of this study was to evaluate the safety and efficacy of combined abdominoplasty and breast surgery at a single plastic surgery practice that performs a large volume of these cases. This is an update to a study published in 2006. METHODS: A retrospective review was performed for patients who underwent combined abdominoplasty and cosmetic breast surgery during the last 10 years at a single outpatient surgery center. Abdominoplasty inclusion criteria were defined as lower, mini, full, reverse, or circumferential abdominoplasty. Cosmetic breast surgery inclusion criteria were defined as augmentation, mastopexy, augmentation-mastopexy, reduction, or removal and replacement of implants. Pertinent preoperative and intraoperative data were recorded along with complications and revisions. RESULTS: There were 268 patients during the 10-year period between 1997 and 2007. There were no cases of death, pulmonary embolism, deep venous thrombosis, or other life-threatening complications. The overall complication rate was 34%. Abdominoplasty seroma and scars requiring revision comprised 68% (n = 74) of the complications. The total revision rate was 13%. CONCLUSIONS: Combined abdominoplasty and cosmetic breast surgery was safe and effective in this large series of cases performed at a single plastic surgery practice. The complication and revision rates of the combined surgery were similar to those reported for individually staged procedures.

Routine underwater seal drains are not required after transthoracic oesophagectomy: a pilot study.

OBJECTIVE: Underwater seal drainage of the pleural cavity has been standard practice after transthoracic oesophagectomy. However these chest tubes cause pain and hamper mobility, thereby causing significant morbidity and delaying recovery. We postulated that if complete lung expansion and optimum pulmonary function could be achieved and maintained following a transthoracic oesophagectomy using simple gravity aided transabdominal tube drainage of the pleural cavity, then these may be a simpler alternative to the conventional underwater seal chest drains. METHODS: A total of 50 patients had transthoracic oesophagectomy for oesophageal cancer. Of the cohort, 44 patients were fitted with the transabdominal drain described and hence had 'modified pleural drainage' following the oesophagectomy. All patients had a posterior mediastinal drain placed in either the right or the left pleural cavity during the oesophagectomy. The tube drain was inserted into the pleural cavity from the abdomen and placed into the desired position across the diaphragmatic hiatus. The drain was managed in the conventional manner and patients were monitored postoperatively for any developing pleural collections through serial chest X-rays. Respiratory function was closely monitored. RESULTS: The drains were removed without any significant respiratory complications by the 8th postoperative day in 86% of the patients. Only three patients (7%) developed clinically significant recurrent pleural effusions, causing respiratory compromise meriting further drainage. This was easily and safely managed using fine bore pigtail drains inserted under ultrasound guidance. CONCLUSION: Transabdominal gravity aided tube drainage of the mediastinum and the pleural cavity is an effective and safe means of draining the chest, following uncomplicated transthoracic oesophagectomy.