The influence of specimen thickness and alignment on the material and failure properties of electrospun polycaprolactone nanofiber mats

Electrospinning is a versatile fabrication technique that has been recently expanded to create nanofibrous structures that mimic ECM topography. Like many materials, electrospun constructs are typically characterized on a smaller scale, and scaled up for various applications. This established practice is based on the assumption that material properties, such as toughness, failure stress and strain, are intrinsic to the material, and thus will not be influenced by specimen geometry. However, we hypothesized that the material and failure properties of electrospun nanofiber mats vary with specimen thickness. To test this, we mechanically characterized polycaprolactone (PCL) nanofiber mats of three different thicknesses in response to constant rate elongation to failure. To identify if any observed thickness-dependence could be attributed to fiber alignment, such as the effects of fiber reorientation during elongation, these tests were performed in mats with either random or aligned nanofiber orientation. Contrary to our hypothesis, the failure strain was conserved across the different thicknesses, indicating similar maximal elongation for specimens of different thickness. However, in both the aligned and randomly oriented groups, the ultimate tensile stress, short-range modulus, yield modulus, and toughness all decreased with increasing mat thickness, thereby indicating that these are not intrinsic material properties. These findings have important implications in engineered scaffolds for fibrous and soft tissue applications (e.g., tendon, ligament, muscle, and skin), where such oversights could result in unwanted laxity or reduced resistance to failure. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2794-2800, 2016.

FIT for the future: a case for risk-based colorectal cancer screening using the faecal immunochemical test

Worldwide, the guaiac faecal occult blood test (gFOBT) is being replaced with the more accurate faecal immunochemical test (FIT) for colorectal cancer (CRC) screening. From January 2016, the National Screening Committee in the UK has recommended a change from the gFOBT to the FIT following a successful Bowel Cancer Screening Programme pilot study with over 40 000 participants. Although the test has shown improved uptake and the ability to detect significantly more colorectal cancers and advanced adenomas, the higher uptake and test positivity will challenge the capacity of colonoscopy services. One of the main advantages of the FIT is that it provides a quantitative haemoglobin concentration which has been shown to relate to the risk of CRC. Risk scoring systems which combine the FIT concentration with risk factor assessment have been shown to improve the sensitivity of the test. This individualized approach to screening could enable those at greatest risk to be referred for colonoscopy, optimizing resource use and ultimately patient outcomes.

Health-related quality of life in Parkinson's: impact of 'off' time and stated treatment preferences

PURPOSE

Long-term levodopa therapy and related fluctuating plasma concentrations are associated with between-dose periods of 'off time' resulting in substantial variation in symptoms and functioning throughout the day in people with Parkinson's (PwP).

METHODS

PwP across UK, France, Spain and Italy completed an online survey to explore: the impact of 'off time' on (1) health-related quality of life (HRQL) and (2) on functioning and ability to undertake usual activities; (3) the value of 'off time' relative to other factors associated with Parkinson's through a stated preference discrete choice experiment (SPDCE).

RESULTS

In total, 305 PwP completed the online survey. Overall mean HRQL (utility) score was significantly lower for 'off time' (0.37) than for 'on time' (0.60). All attributes within the SPDCE were significant predictors of treatment choice, although increased duration of 'on time' (per hour per day: odds ratio (OR) = 1.40) and predictability of 'off time' to within 30 min (OR = 1.42) were valued most highly.

CONCLUSIONS

'On time' and predictability of 'off time' are highly valued by PwP. Due to substantial diurnal variation of Parkinson's symptoms, standard patient-reported outcome (PRO) assessments may not adequately capture the impact of 'off time' on HRQL and participation in daily activities.

Upregulation of gingival tissue miR-200b in obese periodontitis subjects

Increased local immune and inflammatory responses in obese individuals with periodontitis may explain the aggressive clinical presentation and altered treatment response when compared to that of normal weight subjects. Our goal was to identify any differences in microRNA (miRNA) expression profiles of gingival tissue in periodontitis when obesity is present, which may suggest novel molecular pathways that this miRNA network may affect. Total RNA was extracted from gingival tissue biopsies collected from normal weight and obese individuals with periodontitis; miRNA expression profiling was performed with Affymetrix GeneChip miRNA 3.0 arrays; and results were validated with quantitative reverse transcription polymerase chain reaction (qRT-PCR). In silico identification of previously confirmed miRNA gene targets was conducted through miRTarBase and miRWalk databases, and pathway enrichment analysis identified enriched miRNA gene sets. Expression of selected genes in the same biopsy samples was tested with qRT-PCR. The gingival tissue miRNA profile of obese patients, compared to that of normal weight patients, showed 13 upregulated and 22 downregulated miRNAs, among which miR-200b was validated by qRT-PCR to be significantly increased in obesity. Functional analysis of 51 experimentally validated miR-200b gene targets identified enrichment of genes involved in cell motility, differentiation, DNA binding, response to stimulus, and vasculature development pathways not previously identified in the obesity-specific disease profile. Furthermore, the expression of the miR-200b gene targets ZEB1/2, GATA2, and KDR was confirmed by qRT-PCR as being lower in obese patients with periodontitis versus normal weight patients, suggesting a role of miR-200b in regulation of a set of gene targets and biological pathways relevant to wound healing and angiogenesis. Functional studies to explore the role of miR-200b in the above processes may offer new insights on putative therapeutic targets for this group of patients.

Resolution of sleepiness and fatigue: a comparison of bupropion and selective serotonin reuptake inhibitors in subjects with major depressive disorder achieving remission at doses approved in the European Union

Unlike selective serotonin reuptake inhibitors (SSRIs), bupropion may be classified as a dual noradrenaline and dopamine reuptake inhibitor, a difference with potential implications for the treatment of residual sleepiness and fatigue in major depressive disorder (MDD). Post-hoc analysis of subjects with remitted MDD was performed on data pooled from six double-blind, randomized trials comparing the European Union (EU)-approved dose of ≤300 mg/day bupropion with SSRIs (sertraline, paroxetine or escitalopram) for the resolution of sleepiness and fatigue. Hypersomnia score was defined as the sum of scores of the Hamilton Depression Rating Scale (HDRS) items 22, 23, and 24; fatigue score as HDRS item 13 score; and remission as HDRS-17≤7. Similar proportions of bupropion- and SSRI-treated subjects achieved remission at study endpoint (169/343, 49.3% vs 324/656, 49.4%; last observation carried forward (LOCF), p=0.45). Fewer bupropion-treated remitters had residual symptoms of sleepiness (32/169, 18.9% vs 104/324, 32.1%; p<0.01) and fatigue (33/169, 19.5% vs 98/324, 30.2%; p<0.05). Bupropion-treated remitters also showed greater improvement (mean change from baseline) in sleepiness (p<0.05) and fatigue scores (p<0.01) at endpoint: benefits were evident from week 2 for sleepiness (p<0.01) and week 4 for fatigue (p<0.01). Bupropion treatment at the EU-approved dose of ≤300 mg/day may offer advantages over SSRIs in the resolution of sleepiness and fatigue in remitted MDD patients.

Stable free radical from plant litter decomposing in water

The presence of a stable radical species in both fresh straw and that which had been submerged in aerated water for up to six months has been demonstrated using electron paramagnetic (spin) resonance (EPR or ESR) spectroscopy. A radical signal was associated also with material shown to contain straw lignin markers, which was leached from the rotting straw into surrounding water. Fresh straw treated with strong alkali to remove phenolics did not show a radical signal. The possible effect of a dissolved stable free radical is discussed in relation to the antagonistic effect of rotting straw on algal and cyanobacterial growth in water to which straw has been added as a nuisance algal control agent.

Non-steroidal anti-inflammatory drug use and cervical cancer risk: a case-control study using the Clinical Practice Research Datalink

PURPOSE

Non-steroidal anti-inflammatory drugs (NSAIDs) have many anticarcinogenic properties via the inhibition of cyclooxygenase 2 (COX-2). Only one study, a cohort study examining risk of all cancers, investigated their role in cervical cancer with inconsistent findings between non-aspirin NSAIDs and aspirin. The aim of this study was to further investigate NSAID/aspirin use and cervical cancer risk.

METHODS

Using the United Kingdom Clinical Practice Research Datalink, 724 women diagnosed with cervical cancer between 1 January, 1995 and December 2010 were compared to 3479 women (without cervical cancer) matched on year of birth and general practice. Conditional logistic regression analysis adjusted for smoking, sexually transmitted infections, HRT and contraceptive use, was used to calculate odds ratios (OR) and 95% confidence intervals (CI) for cervical cancer risk among users of any oral NSAIDs, non-aspirin NSAIDs and aspirin, as assessed from primary care prescribing data.

RESULTS

Excluding the year prior to diagnosis, there was no association in adjusted analyses between ever vs. never use of an NSAID (OR 0.92, 95% CI 0.77-1.09), non-aspirin NSAID (OR 0.95, 95% CI 0.80-1.13) or low-dose aspirin (OR 1.07, 0.80-1.44) and cervical cancer risk. In analysis of daily defined doses, there was no association with cervical cancer risk comparing the highest users to non-users of NSAIDs (OR 0.98, 95% CI 0.69-1.39) or non-aspirin NSAIDs (OR 1.00, 95% CI 0.70-1.43) or low-dose aspirin (OR 1.04, 95% CI 0.59-1.81).

CONCLUSION

This large historical cohort study found no evidence of an association between non-aspirin NSAID or aspirin use and cervical cancer risk.

Large-scale and highly efficient synthesis of micro- and nano-fibers with controlled fiber morphology by centrifugal jet spinning for tissue regeneration

PLLA fibrous tissue scaffolds with controlled fiber nanoscale surface roughness are fabricated with a novel centrifugal jet spinning process. The centrifugal jet spinning technique is a highly efficient synthesis method for micron- to nano-sized fibers with a production rate up to 0.5 g min(-1). During the centrifugal jet spinning process, a polymer solution jet is stretched by the centrifugal force of a rotating chamber. By engineering the rheological properties of the polymer solution, solvent evaporation rate and centrifugal force that are applied on the solution jet, polyvinylpyrrolidone (PVP) and poly(l-lactic acid) (PLLA) composite fibers with various diameters are fabricated. Viscosity measurements of polymer solutions allowed us to determine critical polymer chain entanglement limits that allow the generation of continuous fiber as opposed to beads or beaded fibers. Above a critical concentration at which polymer chains are partially or fully entangled, lower polymer concentrations and higher centrifugal forces resulted in thinner fibers. Etching of PVP from the PLLA-PVP composite fibers doped with increasing PVP concentrations yielded PLLA fibers with increasing nano-scale surface roughness and porosity, which increased the fiber hydrophilicity dramatically. Scanning electron micrographs of the etched composite fibers suggest that PVP and PLLA were co-contiguously phase separated within the composite fibers during spinning and nano-scale roughness features were created after the partial etching of PVP. To study the tissue regeneration efficacy of the engineered PLLA fiber matrix, human dermal fibroblasts are used to simulate partial skin graft. Fibers with increased PLLA surface roughness and porosity demonstrated a trend towards higher cell attachment and proliferation.

Preoperative exercise capacity in adult inflammatory bowel disease sufferers, determined by cardiopulmonary exercise testing

BACKGROUND AND AIMS

Aerobic exercise capacity appears impaired in children with inflammatory bowel disease (IBD). Whether this holds true in adults with IBD is not known. Using cardiopulmonary exercise testing (CPET), we assessed anaerobic threshold (AT) in such patients comparing data with reference values and other elective surgical patients. We also sought to confirm whether the presence of a fistula further reduced AT.

METHODS

CPET was performed between November 2007 and December 2010 on patients awaiting abdominopelvic surgery. Gender-specific normal reference values were used for comparison. Unadjusted comparison between two groups was made using Mann-Whitney U test and by unpaired t test. Data were adjusted by analysis of covariance, using age and sex as covariates. Differences between patients' observed values and reference values were tested using paired t tests.

RESULTS

Four hundred and fourteen patients (234 male) were studied (mean ± SD age, 56.6 ± 16.4 years; weight, 74.2 ± 15.6 kg). Adjusted AT values in Crohn's disease (CD) were lower than colorectal cancer (11.4 ± 3.4 vs 13.2 ± 3.5 ml.kg(-1).min(-1), p = 0.03) and for all other colorectal disease groups combined (12.6 ± 3.5 ml.kg(-1).min(-1), p = 0.03). AT of Ulcerative colitis (UC) and CD patients together were reduced compared to population reference values (p < 0.05).

CONCLUSION

After adjusting for age and sex, CD patients had a reduced AT compared to patients with colorectal cancer and other colorectal disease groups combined. The pathogenesis of this low AT remains to be defined and warrants further investigation.

Association between the rs1050450 glutathione peroxidase-1 (C > T) gene variant and peripheral neuropathy in two independent samples of subjects with diabetes mellitus

Glutathione peroxidase-1 (GPx-1) is an endogenous anti-oxidant enzyme. The T allele of the GPx-1 rs1050450 (C > T) gene variant is associated with reduced enzyme activity. Our aim was to examine the association between this gene variant and peripheral neuropathy in two cross-sectional samples of subjects with diabetes: (i) 773 Caucasian subjects were genotyped from the UCL Diabetes and Cardiovascular disease Study (UDACS) and (ii) 382 Caucasian subjects from the Ealing Diabetes Study (EDS). Peripheral neuropathy status (and oxidised-LDL [Ox-LDL:LDL] and plasma Total Ant-ioxidant Status [TAOS] in UDACS), were analysed in relation to genotype. We observed that: (i) In UDACS, the odds ratio (OR) for peripheral neuropathy in the T allele carriers compared to the CC genotype was 1.61 [1.10-2.28], p = 0.01. This remained significant after adjustment for other risk factors. Ox-LDL:LDL ratio was significantly elevated in T allele carriers (CC vs. CT/TT: 16.3 ± 2.4 v 18.0 ± 2.9 U/mmol LDL, p = 0.02). (ii) In EDS, the OR for peripheral neuropathy in the T allele carriers compared to the CC genotype was 1.95 [1.11-3.42], p = 0.02. This remained significant after adjustment for other risk factors. In conclusion, we observed a significant association between the T allele and peripheral neuropathy and LDL oxidation. This is the first paper to examine the rs1050450 variant in two samples of Caucasian subjects with diabetes. Prospective analysis of the gene variant is required in diabetic and healthy cohorts with measured plasma markers of oxidative stress to investigate the described association further.

Effect of exercise on the diurnal variation in energy substrate use during a high-fat diet

Aerobic exercise increases 24-h fat oxidation following initiation of a high-fat diet. The objective of this study is to examine the time course of increased fat oxidation under exercise and sedentary conditions. Eighteen healthy subjects completed a randomized crossover design (sedentary and exercise visits) staying for five consecutive days in a metabolic chamber each visit. On day 1, 30% of energy intake was from fat; days 2-5 had 50% of energy as fat. During exercise, subjects rode on a stationary cycle at 45% of VO2max for 1 h in the mornings and evenings. Respiratory gases and urinary nitrogen were collected to calculate macronutrient oxidation and non-protein respiratory exchange ratio (NPRER). This data, collected continuously (24-h periods), were subsequently divided into three time segments: (1) exercise + recovery (1000-1200 hours, 2100-2200 hours), (2) sleep (2300-0645 hours), and (3) wake (all remaining hours). NPRER on exercise versus sedentary visits was lower for the sleep segment (0.77 ± 0.01 01 vs. 0.81 ± 0.01, p < 0.001), higher for the exercise + recovery segment (0.88 ± 0.01 vs. 0.86 ± 0.01, p < 0.001), and was not different for the wake segment. Fat oxidation was significantly higher for exercise versus sedentary treatments during sleep (41 ± 2 vs. 31 ± 2 g), wake (62 ± 3 vs. 51 ± 3 g), and exercise + recovery segments (33 ± 3 vs.16 ± 1 g), but so was fat intake by design (171 ± 8 vs. 128 ± 7 g/d). Although exercise showed greater fat oxidation during all segments, dietary fat intake was also higher. Therefore, based on NPRER, the time of day during which the exercise treatment increased the ratio of fat to carbohydrate oxidation was during sleep.

Variants of ADRA2A are associated with fasting glucose, blood pressure, body mass index and type 2 diabetes risk: meta-analysis of four prospective studies

AIMS/HYPOTHESIS

We quantified the effect of ADRA2A (encoding α-2 adrenergic receptor) variants on metabolic traits and type 2 diabetes risk, as reported in four studies.

METHODS

Genotype data for ADRA2A single nucleotide polymorphisms (SNPs) rs553668 and rs10885122 were analysed in >17,000 individuals (1,307 type 2 diabetes cases) with regard to metabolic traits and type 2 diabetes risk. Two studies (n = 9,437), genotyped using the Human Cardiovascular Disease BeadChip, provided 12 additional ADRA2A SNPs.

RESULTS

Rs553668 was associated with per allele effects on fasting glucose (0.03 mmol/l, p = 0.016) and type 2 diabetes risk (OR 1.17, 95% CI 1.04-1.31; p = 0.01). No significant association was observed with rs10885122. Of the 12 SNPs, several showed associations with metabolic traits. Overall, after variable selection, rs553668 was associated with type 2 diabetes risk (OR 1.38, 95% CI 1.09-1.73; p = 0.007). rs553668 (per allele difference 0.036 mmol/l, 95% CI 0.008-0.065) and rs17186196 (per allele difference 0.066 mmol/l, 95% CI 0.017-0.115) were independently associated with fasting glucose, and rs17186196 with fasting insulin and HOMA of insulin resistance (4.3%, 95% CI 0.6-8.1 and 4.9%, 95% CI 1.0-9.0, respectively, per allele). Per-allele effects of rs491589 on systolic and diastolic blood pressure were 1.19 mmHg (95% CI 0.43-1.95) and 0.61 mmHg (95% CI 0.11-1.10), respectively, and those of rs36022820 on BMI 0.58 kg/m(2) (95% CI 0.15-1.02).

CONCLUSIONS/INTERPRETATION

Multiple ADRA2A SNPs are associated with metabolic traits, blood pressure and type 2 diabetes risk. The α-2 adrenergic receptor should be revisited as a therapeutic target for reduction of the adverse consequences of metabolic trait disorders and type 2 diabetes.

Genetic variation within IL18 is associated with insulin levels, insulin resistance and postprandial measures

BACKGROUND AND AIMS

IL-18 expression is up-regulated in atherosclerotic plaques, and higher levels are seen in obese and Type 2 Diabetic individuals. More recently, a possible role for IL-18 in glucose and energy homeostasis has been suggested.

METHODS AND RESULTS

We investigated variation within the IL18 gene and its association with measures of obesity and the metabolic syndrome. Five IL18 tagging single nucleotide polymorphisms (rs1946519, rs2043055, rs549908, rs360729, rs3882891) were selected and genotyped in the Gene-Diet Attica Investigation on childhood obesity (GENDAI) (age range 10-14 yrs); in young European men in the second European Atherosclerosis Research offspring Study (EARSII), an offspring study (age range 18-28 yrs) and in a group of healthy women from the Greek Obese Women study (GrOW) (age range 18-74 yrs). Six common haplotypes were observed. In GrOW, Hap6 (Frequency-2.6%) was associated with higher insulin levels (p<0.0001), estimates of HOMA(-Insulin Resistance) (p<0.0001) and HOMA(-β-cell) (p<0.0001) compared to the common haplotype Hap1 (Frequency-33.2%). In EARSII, rs2043055 was associated with peak and area under the curve triglycerides (p=0.001 and p=0.002, respectively) after an oral fat tolerance test in 'cases' but not 'controls'. None of the haplotypes were associated with measures of body fatness in any of the studies.

CONCLUSION

Association of IL18 variation with insulin levels and estimates of insulin resistance were only observed in our adult study, suggesting that the effects of IL-18 are only associated with increasing age. Taken together with the association of IL18 variants with post-prandial measures, this provides support for IL-18 as a metabolic factor.

Fiber Based Tissue Engineered Scaffolds for Musculoskeletal Applications: in Vitro Cellular Response

The architecture of an engineered scaffold is an important consideration in the design of a synthetic tissue replacement. We have begun to explore the use of heirarchical fiber scale design ranging from microscale nonwoven to 3-D integrated fiber bundles in orthopaedic tissue engineering applications. The use of heirarchical fiber and design includes the following advantages: 1) the ability to tailor a broad spectrum of substrates with a wide range of mechanical properties, and 2) the ability to create structures capable of supporting cell proliferation as well as the micro-diffusion of nutrients throughout the structure. Using the bioresorbable copolymer, poly(D,L-lactide-co-glycolide) [PLAGA], we have fabricated two matrices based on fiber technology: 1) a microfiber non-woven mesh composed of 50:50 PLAGA and 2) a 3-dimensional braided structure composed of 5:95 PLAGA. These structures were examined by scanning electron microscopy [SEM] in an in vitro cell culture environment. Matrices were seeded with two types of cells (osteoblasts from neonatal rat calvaria and fibroblasts from the BALB/C cell line) to determine the effect of matrix architecture on cellular morphology and proliferation. SEM analysis of the microfiber matrix indicated a highly porous, structure resulting from the random arrangement of the microfibers. PLAGA fibers appear to have a range in diameter from approximately 2-7 μm. The 3-D braided matrix was shown to have a organized fibrous structure resulting from the 3-D braiding process. Examination of the attachment and proliferation of cells on the matrices revealed that cell morphology and proliferation patterns were dependent on cell type and matrix geometry. SEM analysis also indicated that cells responded dynamically to changes in structure due to the onset of degradation.

Experimental classical bovine spongiform encephalopathy: definition and progression of neural PrP immunolabeling in relation to diagnosis and disease controls

Tissues from sequential-kill time course studies of bovine spongiform encephalopathy (BSE) were examined to define PrP immunohistochemical labeling forms and map disease-specific labeling over the disease course after oral exposure to the BSE agent at two dose levels. Study was confined to brainstem, spinal cord, and certain peripheral nervous system ganglia-tissues implicated in pathogenesis and diagnosis or disease control strategies. Disease-specific labeling in the brainstem in 39 of 220 test animals showed the forms and patterns observed in natural disease and invariably preceded spongiform changes. A precise temporal pattern of increase in labeling was not apparent, but labeling was generally most widespread in clinical cases, and it always involved neuroanatomic locations in the medulla oblongata. In two cases, sparse labeling was confined to one or more neuroanatomic nuclei of the medulla oblongata. When involved, the spinal cord was affected at all levels, providing no indication of temporal spread within the cord axis or relative to the brainstem. Where minimal PrP labeling occurred in the thoracic spinal cord, it was consistent with initial involvement of general visceral efferent neurons. Labeling of ganglia involved only sensory ganglia and only when PrP was present in the brainstem and spinal cord. These experimental transmissions mimicked the neuropathologic findings in BSE-C field cases, independent of dose of agent or stage of disease. The model supports current diagnostic sampling approaches and control measures for the removal and destruction of nervous system tissues in slaughtered cattle.

Impact of exercise and dietary fatty acid composition from a high-fat diet on markers of hunger and satiety

To compare the effects of both dietary fatty acid composition and exercise vs. sedentary conditions on circulating levels of hunger and satiety hormones. Eight healthy males were randomized in a 2 × 2 crossover design. The four treatments were 3 days of HF diets (50% of energy) containing high saturated fat (22% of energy) with exercise (SE) or sedentary (SS) conditions, and high monounsaturated fat (30% of energy) with exercise (UE) or sedentary (US) conditions. Cycling exercise was completed at 45% of VO(2)max for 2h daily. On the third HF day, 20 blood samples were drawn over a 24h period for each hormone (leptin, insulin, ghrelin, and peptide YY (PYY)). A visual analog scale (VAS) was completed hourly between 0800 and 2200. Average 24h leptin and insulin levels were lower while 24h PYY was higher during exercise vs. sedentary conditions. FA composition did not differentially affect 24h hormone values. VAS scores for hunger and fullness did not differ between any treatment but did correlate with ghrelin, leptin, and insulin. High saturated or unsaturated fat diets did not differ with respect to markers of hunger or satiety. Exercise decreased 24h leptin and insulin while increasing PYY regardless of FA composition.