Tumour associated vasculature-on-a-chip for the evaluation of microbubble-mediated delivery of targeted liposomes

The vascular system is the primary route for the delivery of therapeutic drugs throughout the body and is an important barrier at the region of disease interest, such as a solid tumour. The development of complex 3D tumour cultures has progressed significantly in recent years however, the generation of perfusable vascularised tumour models still presents many challenges. This study presents a microfluidic-based vasculature system that can be induced to display properties of tumour-associated blood vessels without direct incorporation of tumour cells. Conditioning healthy endothelial–fibroblast cell vasculature co-cultures with media taken from tumour cell cultures was found to result in the formation of disorganised, tortuous networks which display characteristics consistent with those of tumour-associated vasculature. Integrin αvβ3, a cell adhesion receptor associated with angiogenesis, was found to be upregulated in vasculature co-cultures conditioned with tumour cell media (TCM) – consistent with the reported αvβ3 expression pattern in angiogenic tumour vasculature in vivo. Increased accumulation of liposomes (LSs) conjugated to antibodies against αvβ3 was observed in TCM networks compared to non-conditioned networks, indicating αvβ3 may be a potential target for the delivery of drugs specifically to tumour vasculature. Furthermore, the use of microbubbles (MBs) and ultrasound (US) to further enhance the delivery of LSs to TCM-conditioned vasculature was investigated. Quantification of fluorescent LS accumulation post-perfusion of the vascular network showed 3-fold increased accumulation with the use of MBs and US, suggesting that targeted LS delivery could be further improved with the use of locally administered MBs and US

High-throughput microfluidics for evaluating microbubble enhanced delivery of cancer therapeutics in spheroid cultures

Drug penetration into solid tumours remains a major challenge in the effective treatment of cancer. Microbubble (MB) mediated sonoporation offers a potential solution to this by enhancing the uptake of drugs into cells. Additionally, in using an ultrasound (US) trigger, drug delivery can be localised to the tumour, thus reducing the off-site toxicity associated with systemic delivery. The majority of in vitro studies involving the observation of MB-enhanced drug efficacy have been conducted on 2D monolayer cell cultures, which are known to be poor models for in vivo tumours. 3D spheroid cultures allow for the production of multicellular cultures complete with extracellular matrix (ECM) components. These cultures effectively recreate many of the physiological features of the tumour microenvironment and have been shown to be far superior to previous 2D monolayer models. However, spheroids are typically handled in well-plates in which the fluid environment is static, limiting the physiological relevance of the model. The combination of 3D cultures and microfluidics would allow for the production of a dynamic system in which spheroids are subjected to in vivo like fluid flow and shear stressesThis study presents a microfluidic device containing an array of spheroid traps, into which multiple pre-grown colorectal cancer (CRC) spheroids were loaded. Reservoirs interfaced with the chip use hydrostatic pressure to passively drive flow through the system and subject spheroids to capillary like flow velocities. The use of reservoirs also enabled multiple chips to be run in parallel, allowing for the screening of multiple therapeutic treatments (n = 690 total spheroids analysed). This microfluidic platform was used to investigate MB enhanced drug delivery and showed that co-delivery of 3 μM doxorubicin (DOX) + MB + US reduced spheroid viability to 48 ± 2%, compared to 75 ± 5% observed with 3 μM DOX alone. Delivery of drug loaded MBs (DLMBs), in which DOX-loaded liposomes (DOX-LS) were conjugated to MBs, reduced spheroid viability to 62 ± 3%, a decrease compared to the 75 ± 3% viability observed with DOX-LS in the absence of MBs + US

Nf2/Merlin controls spinal cord neural progenitor function in a Rac1/ErbB2-dependent manner

Objective: Individuals with the neurofibromatosis type 2 (NF2) cancer predisposition syndrome develop spinal cord glial tumors (ependymomas) that likely originate from neural progenitor cells. Whereas many spinal ependymomas exhibit indolent behavior, the only treatment option for clinically symptomatic tumors is surgery. In this regard, medical therapies are unfortunately lacking due to an incomplete understanding of the critical growth control pathways that govern the function of spinal cord (SC) neural progenitor cells (NPCs). Methods: To identify potential therapeutic targets for these tumors, we leveraged primary mouse Nf2-deficient spinal cord neural progenitor cells. Results: We demonstrate that the Nf2 protein, merlin, negatively regulates spinal neural progenitor cell survival and glial differentiation in an ErbB2-dependent manner, and that NF2-associated spinal ependymomas exhibit increased ErbB2 activation. Moreover, we show that Nf2-deficient SC NPC ErbB2 activation results from Rac1-mediated ErbB2 retention at the plasma membrane. Significance: Collectively, these findings establish ErbB2 as a potential rational therapeutic target for NF2-associated spinal ependymoma

Progressive GAA·TTC Repeat Expansion in Human Cell Lines

Trinucleotide repeat expansion is the genetic basis for a sizeable group of inherited neurological and neuromuscular disorders. Friedreich ataxia (FRDA) is a relentlessly progressive neurodegenerative disorder caused by GAA·TTC repeat expansion in the first intron of the FXN gene. The expanded repeat reduces FXN mRNA expression and the length of the repeat tract is proportional to disease severity. Somatic expansion of the GAA·TTC repeat sequence in disease-relevant tissues is thought to contribute to the progression of disease severity during patient aging. Previous models of GAA·TTC instability have not been able to produce substantial levels of expansion within an experimentally useful time frame, which has limited our understanding of the molecular basis for this expansion. Here, we present a novel model for studying GAA·TTC expansion in human cells. In our model system, uninterrupted GAA·TTC repeat sequences display high levels of genomic instability, with an overall tendency towards progressive expansion. Using this model, we characterize the relationship between repeat length and expansion. We identify the interval between 88 and 176 repeats as being an important length threshold where expansion rates dramatically increase. We show that expansion levels are affected by both the purity and orientation of the repeat tract within the genomic context. We further demonstrate that GAA·TTC expansion in our model is independent of cell division. Using unique reporter constructs, we identify transcription through the repeat tract as a major contributor to GAA·TTC expansion. Our findings provide novel insight into the mechanisms responsible for GAA·TTC expansion in human cells

Neoumbilicoplasty with a Superiorly Based Abdominal Skin Flap

Summary:. We propose a neoumbilicoplasty technique that can be applied when the umbilical stalk becomes disrupted during an abdominoplasty. This case used surgical concepts that involved progressive thinning of the flap in a 3-cm radius around the neoumbilicus, with increased thinning toward the neoumbilical position. This was followed with suture tacking of the thinned abdominal flap to create a concavity around the neoumbilicus. A longer “U” shaped incision was created and also sutured down to abdominal wall to recreate an umbilical “floor” with the adjacent skin sutured to the superior-based flap to construct the walls of the neoumbilicus. An aesthetically pleasing umbilicus resulted with high patient satisfaction and a lack of postoperative complications. There were no additional scars extending beyond the umbilical region

Peroneal Nerve Repair of a 9 Year Old: Return of Motor Function after 2 Years

Summary:. Major factors that influence functional nerve recovery, postrepair, are length of the nerve defect, type of injury, operative technique, time until treatment, and age of the patient. We present a severe motor nerve defect in a complicated peroneal nerve injury in a 9-year-old that showed functional return after a delayed period of 23 months with sural nerve cable grafting. This case revealed the increased resiliency and regenerative capacity of motor end plates in young patients. In conclusion, autograft for a deep peroneal nerve repair, by means of sural nerve graft, proved to be an acceptable option in children

Mosaic Fleur-de-Profunda Artery Perforator Flap for Autologous Breast Reconstruction

Summary:. Perforator-free flaps, in autologous breast reconstruction, have expanded to exploit tissue available at smaller donor sites while retaining high success and low risk rates. Abdominal based flaps, such as the deep inferior epigastric perforator, remain the most common; however, when the abdomen is not an appropriate donor site, lower extremity flaps are options. The profunda artery perforator has the benefit of hiding unsightly scar in the gluteal crease but has the drawback of poor donor site volume. Our mosaic fleur-de-profunda artery perforator flap technique for breast reconstruction has shown to increase volume with the addition of a vertical limb, include full angiosome of perforators, and exhibit donor site morbidity equivalent to a medial thigh lift

American Society of Plastic Surgeons Member Post-Operative Opioid Prescribing Patterns

Introduction:. Despite the widespread use of opioids in pain management, there are currently no evidence-based guidelines for the treatment of postoperative pain with opioids. Although other surgical specialties have begun researching their pain prescribing patterns, there has yet to be an investigation to unravel opioid prescribing patterns among plastic surgeons. Methods:. Survey Monkey was used to sample the American Society of Plastic Surgeons (ASPS) members regarding their opioid prescribing practice patterns. The survey was sent randomly to 50% of ASPS members. Respondents were randomized to 1 of 3 different common elective procedures in plastic surgery: breast augmentation, breast reduction, and abdominoplasty. Results:. Of the 5,770 overall active ASPS members, 298 responses (12% response rate) were received with the following procedure randomization results: 106 for breast augmentation, 99 for breast reduction, and 95 for abdominoplasty. Overall, 80% (N = 240) of respondents used nonnarcotic adjuncts to manage postoperative pain, with 75.4% (N = 181) using nonnarcotics adjuncts >75% of the time. The most commonly prescribed narcotics were Hydrocodone with Acetaminophen (Lortab, Norco) and Oxycodone with Acetaminophen (Percocet, Oxycocet) at 42.5% (N = 116) and 38.1% (N = 104), respectively. The most common dosage was 5 mg (80.4%; N = 176), with 48.9% (N = 107) mostly dispensing 20–30 tablets, and the majority did not give refills (94.5%; N = 207). Conclusions:. Overall, plastic surgeons seem to be in compliance with proposed American College of Surgeon’s opioid prescription guidelines. However, there remains a lack of evidence regarding appropriate opioid prescribing patterns for plastic surgeons

Accounting for habitat when considering climate: has the niche of the Adonis blue butterfly changed in the UK?

The dramatic recovery of three species of grassland specialist butterfly threatened with extinction at their high latitude range limits in the 1980s has been attributed to two factors: increased grazing on calcareous grassland sites and warmer air temperatures. Both result in the warming of soil surface temperatures, favourable to the larvae of these species. We address the influence of both of these factors on the habitat usage of the butterfly Polyommatus bellargus, undergoing recovery at its northern range edge. We test the hypothesis that the larval niche of P. bellargus has become less constrained in the past three decades, whilst controlling for changes in habitat structure. Once habitat change has been accounted for we find no evidence for a broadening of the larval niche of P. bellargus. Further, we show that coincident with the recovery of P. bellargus there have been drastic reductions in average turf height across UK chalk grasslands, but changes in air temperature have been highly variable. We conclude that changes to soil surface temperatures caused by reducing turf heights will have been a more consistent influence than air temperature increases, and so habitat improvements through increased grazing will have been the major driver of recovery in P. bellargus. We consider the need to account for changes in habitat when exploring the impacts of recent climate change on local habitats in thermophilous species, and emphasise the continued importance of habitat management to support such species under variable local climates