Acoustic and Magnetic Techniques for the Isolation and Analysis of Cells in Microfluidic Platforms

Cancer comprises a collection of diseases, all of which begin with abnormal tissue growth from various stimuli, including (but not limited to): heredity, genetic mutation, exposure to harmful substances, radiation as well as poor dieting and lack of exercise. The early detection of cancer is vital to providing life-saving, therapeutic intervention. However, current methods for detection (e.g., tissue biopsy, endoscopy and medical imaging) often suffer from low patient compliance and an elevated risk of complications in elderly patients. As such, many are looking to “liquid biopsies” for clues into presence and status of cancer due to its minimal invasiveness and ability to provide rich information about the native tumor. In such liquid biopsies, peripheral blood is drawn from patients and is screened for key biomarkers, chiefly circulating tumor cells (CTCs). Capturing, enumerating and analyzing the genetic and metabolomic characteristics of these CTCs may hold the key for guiding doctors to better understand the source of cancer at an earlier stage for more efficacious disease management.

The isolation of CTCs from whole blood, however, remains a significant challenge due to their (i) low abundance, (ii) lack of a universal surface marker and (iii) epithelial-mesenchymal transition that down-regulates common surface markers (e.g., EpCAM), reducing their likelihood of detection via positive selection assays. These factors potentiate the need for an improved cell isolation strategy that can collect CTCs via both positive and negative selection modalities as to avoid the reliance on a single marker, or set of markers, for more accurate enumeration and diagnosis.

The technologies proposed herein offer a unique set of strategies to focus, sort and template cells in three independent microfluidic modules. The first module exploits ultrasonic standing waves and a class of elastomeric particles for the rapid and discriminate sequestration of cells. This type of cell handling holds promise not only in sorting, but also in the isolation of soluble markers from biofluids. The second module contains components to focus (i.e., arrange) cells via forces from acoustic standing waves and separate cells in a high throughput fashion via free-flow magnetophoresis. The third module uses a printed array of micromagnets to capture magnetically labeled cells into well-defined compartments, enabling on-chip staining and single cell analysis. These technologies can operate in standalone formats, or can be adapted to operate with established analytical technologies, such as flow cytometry. A key advantage of these innovations is their ability to process erythrocyte-lysed blood in a rapid (and thus high throughput) fashion. They can process fluids at a variety of concentrations and flow rates, target cells with various immunophenotypes and sort cells via positive (and potentially negative) selection. These technologies are chip-based, fabricated using standard clean room equipment, towards a disposable clinical tool. With further optimization in design and performance, these technologies might aid in the early detection, and potentially treatment, of cancer and various other physical ailments.

Outcomes and Predictors of Mortality in Neurosurgical Patients at Mbarara Regional Referral Hospital

Background:

Knowing the scope of neurosurgical disease at Mbarara Hospital is critical for infrastructure planning, education and training. In this study, we aim to evaluate the neurosurgical outcomes and identify predictors of mortality in order to potentiate platforms for more effective interventions and inform future research efforts at Mbarara Hospital.

Methods:

This is retrospective chart review including patients of all ages with a neurosurgical disease or injury presenting to Mbarara Regional Referral Hospital (MRRH) between January 2012 to September 2015. Descriptive statistics were presented. A univariate analysis was used to obtain the odds ratios of mortality and 95% confidence intervals. Predictors of mortality were determined using multivariate logistic regression model.

Results:

A total of 1876 charts were reviewed. Of these, 1854 (had complete data and were?) were included in the analysis. The overall mortality rate was 12.75%; the mortality rates among all persons who underwent a neurosurgical procedure was 9.72%, and was 13.68% among those who did not undergo a neurosurgical procedure. Over 50% of patients were between 19 and 40 years old and the majority of were males (76.10%). The overall median length of stay was 5 days. Of all neurosurgical admissions, 87% were trauma patients. In comparison to mild head injury, closed head injury and intracranial hematoma patients were 5 (95% CI: 3.77, 8.26) and 2.5 times (95% CI: 1.64,3.98) more likely to die respectively. Procedure and diagnostic imaging were independent negative predictors of mortality (P <0.05). While age, ICU admission, admission GCS were positive predictors of mortality (P <0.05).

Conclusions:

The majority of hospital admissions were TBI patients, with RTIs being the most common mechanism of injury. Age, ICU admission, admission GCS, diagnostic imaging and undergoing surgery were independent predictors of mortality. Going forward, further exploration of patient characteristics is necessary to fully describe mortality outcomes and implement resource appropriate interventions that ultimately improve morbidity and mortality.

Yielding Behaviour of Electron Beam Lithography and Focused Ion Beam Made Nanocrystalline Micro/Nanopillars

Electron beam lithography (EBL) and focused ion beam (FIB) methods were developed in house to fabricate nanocrystalline nickel micro/nanopillars so to compare the effect of fabrication on plastic yielding. EBL was used to fabricate 3 μm and 5 μm thick poly-methyl methacrylate patterned substrates in which nickel pillars were grown by electroplating with height to diameter aspect ratios from 2:1 to 5:1. FIB milling was used to reduce larger grown pillars to sizes similar to EBL grown pillars. X-ray diffraction, electron back-scatter diffraction, scanning electron microscopy, and FIB imaging were used to characterize the nickel pillars. The measured grain size of the pillars was 91±23 nm, with strong <110> and weaker <111> and <110> crystallographic texture in the growth. Load-controlled compression tests were conducted using a MicroMaterials nano-indenter equipped with a 10 μm flat punch at constant rates from 0.0015 to 0.03 mN/s on EBL grown pillars, and 0.0015 and 0.015 mN/s on FIB-milled pillars. The measured Young’s modulus ranged from 55 to 350 GPa for all pillars, agreeing with values in the literature. EBL grown pillars exhibited stochastic strain-bursts at slow loading rates, attributed to local micro yield events, followed by work hardening. Sharp yield points were also observed and attributed to the gold seed layer de-bonding between the nickel pillar and substrate due to the shear stress associated with end effects that arise from the substrate constraint. The onset of yield ranged from 108 to 1800 MPa, which is greater than bulk nickel, but within values given in the literature. FIB-milled pillars demonstrated stochastic yield behaviour at all loading rates tested, yielding between 320 and 625 MPa. Deformation was apparent at FIB-milled pillar tops, where the smallest cross-sectional area was measured, but still exhibited superior yield strength to bulk nickel. The gallium damage at the outer surface of the pillars likely aids in dislocation nucleation and plasticity, leading to lower yield strengths than for the EBL pillars. Thermal drift, substrate effects, and noise due to vibrations within the indenter system contributed to variance and inconsistency in the data.

High Formalism: The aerial view and the colour field

Laura Kurgan’s Monochrome Landscapes (2004), first exhibited in the Whitney Museum of American Art in New York City, consists of four oblong Cibachrome prints derived from digital files sourced from the commercial Ikonos and QuickBird satellites. The prints are ostensibly flat, depthless fields of white, green, blue, and yellow, yet the captions provided explain that the sites represented are related to contested military, industrial, and cartographic practices. In Kurgan’s account of Monochrome Landscapes she explains that it is in dialogue with another work from the Whitney by abstract artist Ellsworth Kelly. This article pursues the relationship between formalist abstraction and satellite imaging in order to demonstrate how formalist strategies aimed at producing an immediate retinal response are bound up with contemporary uses of digital information and the truth claims such information can be made to substantiate.

Performance Evaluation of a Statistical and a Neural Network Model for Nonrigid Shape-Based Registration

Shape-based registration methods frequently encounters in the domains of computer vision, image processing and medical imaging. The registration problem is to find an optimal transformation/mapping between sets of rigid or nonrigid objects and to automatically solve for correspondences. In this paper we present a comparison of two different probabilistic methods, the entropy and the growing neural gas network (GNG), as general feature-based registration algorithms. Using entropy shape modelling is performed by connecting the point sets with the highest probability of curvature information, while with GNG the points sets are connected using nearest-neighbour relationships derived from competitive hebbian learning. In order to compare performances we use different levels of shape deformation starting with a simple shape 2D MRI brain ventricles and moving to more complicated shapes like hands. Results both quantitatively and qualitatively are given for both sets.

Heart failure in sub-Saharan Africa: review of the aetiology of heart failure and the role of point-of-care biomarker diagnostics

Within Africa, the burden of heart failure is significant. This arises from the increase in cardiovascular disease and associated risk factors such as hypertension and diabetes, as well as causes of heart failure which are particular to sub-Saharan Africa, such as endomyocardial fibrosis. The lack of access to echocardiography and other imaging modalities, from a cost and technical perspective, combined with the predominantly rural nature of many countries with poor transport links, means that the vast majority of people never obtain an appropriate diagnosis. Similarly, research has been limited on the causes and treatment of heart failure in Africa and in particular endemic causes such as EMF and rheumatic heart disease. This review outlines the burden of heart failure in Africa and highlights the opportunity to expand diagnosis through the use of biomarkers, in particular natriuretic peptides. This builds on the success of point-of-care testing in human immunodeficiency virus and tuberculosis which have been extensively deployed in community settings in Africa.

A phase I pharmacokinetic and pharmacodynamic study of the oral mitogen-activated protein kinase kinase (MEK) inhibitor, WX-554, in patients with advanced solid tumours

Purpose: We performed a multi-centre phase I study to assess the safety, pharmacokinetics (PK) and pharmacodynamics (PD) of the orally available small molecule mitogen-activated protein kinase kinase (MEK) 1/2 inhibitor, WX-554, and to determine the optimal biological dose for subsequent trials.
Experimental design: Patients with treatment-refractory, advanced solid tumours, with adequate performance status and organ function were recruited to a dose-escalation study in a standard 3 + 3 design. The starting dose was 25 mg orally once weekly with toxicity, PK and PD guided dose-escalation with potential to explore alternative schedules.
Results: Forty-one patients with advanced solid tumours refractory to standard therapies and with adequate organ function were recruited in eight cohorts up to doses of 150 mg once weekly and 75 mg twice weekly. No dose-limiting toxicities were observed during the study, and a maximum tolerated dose (MTD) was not established. The highest dose cohorts demonstrated sustained inhibition of extracellular signal-regulated kinase (ERK) phosphorylation in peripheral blood mononuclear cells following ex-vivo phorbol 12-myristate 13-acetate stimulation. There was a decrease of 70 ± 26% in mean phosphorylated (p)ERK in C1 day 8 tumour biopsies when compared with pre-treatment tumour levels in the 75 mg twice a week cohort. Prolonged stable disease (>6 months) was seen in two patients, one with cervical cancer and one with ampullary carcinoma.
Conclusions: WX-554 was well tolerated, and an optimal biological dose was established for further investigation in either a once or twice weekly regimens. The recommended phase 2 dose is 75 mg twice weekly.

Bespoke Radiology e-Learning

Introduction: Foundation doctors are expected to assess and interpret plain x-ray studies of the chest/abdomen before a definitive report is issued by senior staff. The Royal College of Radiologists have published guidelines (RCR curriculum) on the scope of plain film findings medical students should be familiar with.1 Studies have shown that the x-ray interpretation without feedback does not significantly improve diagnostic ability. 2 Queen’s University, Belfast Trust Radiology and Experior Medical developed an online system to assess individual student ability to interpret X-ray findings. Over a series of assessments each student’s profile is built up, identifying strengths and weakness. The system can then create bespoke individual assessments re-evaluating previously identified weak areas and quantifying interpretative skill improvement. Aim: To determine how readily an online system is adopted by senior medical students, investigating if increasing exposure to x-ray interpretation combined with cyclical formative feedback enhances performance. Methods: The system was offered to all 270 final year medical students as an online resource. The system comprised a series of 20 weekly 30 minute assessments, containing normal and abnormal x-rays within the RCR curriculum. After each assessment students were given formative feedback, including their own result, annotated answers, peer group comparison and a breakdown of areas of strength and weakness. Focus groups of 4-5 students addressed student perspectives of the system, including ease of use, image resolution, system performance across different operating platforms, perceived value of formative feedback loops, breakdown of performance and the value of bespoke personalised assessments. Research Ethics Approval was granted for the study. Data analysis was via two-sided one-sample t-test; initial minimal recruitment was estimated as 60 students, to detect a mean 10% change in performance, with a standard deviation of 20%. Results and Discussion: Over 80% (n = XXX/270) of the student cohort engaged with the study. Student baseline average was 39%, increasing to 62% by the exit test. The steadily sustained improvement (57% relative performance in interpretative diagnostic accuracy) was despite increasing test difficulty. Student feedback via focus groups was universally positive throughout the examined domains. Conclusion: The online resource proved to be valuable, with high levels of student engagement, improving performance despite increasingly difficulty testing and positive learner experience with the system. References: 1. Undergraduate Radiology Curriculum, The Royal College of Ra, April 2012. Ref No. BFCR(12)4 The Royal College of Radiologists, April 2012 2. I Satia, S Bashagha, A Bibi, R Ahmed, S Mellor, F Zaman. Assessing the accuracy and certainty in interpretating chest x-rays in the medical division. Clin Med August 2013 Vol.13 no. 4 349-352

Bacteriologic investigation of the effects of sodium hypochlorite and chlorhexidine during the endodontic treatment of teeth with apical periodontitis

SIQUEIRA JR. et al. Bacteriologic investigation of the effects of sodium hypochlorite and chlorhexidine during the endodontic treatment of teeth with apical periodontitis. Oral Surg. Oral Med. Oral Pathol. Oral Radiol. Endod., v. 104, n. 1, p. 122-130, 2007.

Exploring Habitability Markers, Biosignatures, and Their False Positives Using Spectral Models of Terrestrial Exoplanets

Thesis (Ph.D.)--University of Washington, 2016-08

Calcaneus-navicular coalition associated to flatfoot in a child. A case report

Tarsal coalition (a congenital fibrous, cartilaginous or bony connection between two bones) often leads to a flatfoot deformity in children. Usually it presents with recurrent ankle sprains or insidious onset of a painful rigid flatfoot and movement limitation of midtarsal and subtalar joints. Clinical diagnosis is confirmed by X-rays, computed axial tomography and nuclear magnetic resonance. The anteater nose sign is caused by a tubular elongation of the anterior process of the calcaneus that approaches or overlaps the tarsal scaphoid (navicular) and resembles the nose of an anteater on a lateral foot or ankle radiograph. The treatment of this union is primarily symptomatic but if the pain persists must be surgical .

Pancreatic pseudocyst: case report and short literature review

We report a case of pancreatic pseudocyst secondary to acute necrotizing pancreatitis treated with open cystogastrostomy. Following a literature review, we stress the enormous benefits offered by modern diagnostic techniques, and especially imaging techniques, for the diagnosis and monitoring of this disease. Treatment should be delayed for at least six weeks, following which the drainage by open surgery offers the best results and lowest morbidity and mortality, followed by laparoscopy and endoscopy, indicated in particular cases and in patients where open surgery is contraindicated.

Bacteriologic investigation of the effects of sodium hypochlorite and chlorhexidine during the endodontic treatment of teeth with apical periodontitis

SIQUEIRA JR. et al. Bacteriologic investigation of the effects of sodium hypochlorite and chlorhexidine during the endodontic treatment of teeth with apical periodontitis. Oral Surg. Oral Med. Oral Pathol. Oral Radiol. Endod., v. 104, n. 1, p. 122-130, 2007.