Correction: The nanotipped hairs of gecko skin and biotemplated replicas impair and/or kill pathogenic bacteria with high efficiency.

Correction for 'The nanotipped hairs of gecko skin and biotemplated replicas impair and/or kill pathogenic bacteria with high efficiency' by X. Li, et al., Nanoscale, 2016, 8, 18860-18869.

The nanotipped hairs of gecko skin and biotemplated replicas impair and/or kill pathogenic bacteria with high efficiency.

We show that gecko microspinules (hairs) and their equivalent replicas, bearing nanoscale tips, can kill or impair surface associating oral pathogenic bacteria with high efficiency even after 7 days of repeated attacks. Scanning Electron Microscopy suggests that there is more than one mechanism contributing to cell death which appears to be related to the scaling of the bacteria type with the hair arrays and accessibility to the underlying nano-topography of the hierarchical surfaces.

Diversification and enrichment of clinical biomaterials inspired by Darwinian evolution.

UNLABELLED: Regenerative medicine and biomaterials design are driven by biomimicry. There is the essential requirement to emulate human cell, tissue, organ and physiological complexity to ensure long-lasting clinical success. Biomimicry projects for biomaterials innovation can be re-invigorated with evolutionary insights and perspectives, since Darwinian evolution is the original dynamic process for biological organisation and complexity. Many existing human inspired regenerative biomaterials (defined as a nature generated, nature derived and nature mimicking structure, produced within a biological system, which can deputise for, or replace human tissues for which it closely matches) are without important elements of biological complexity such as, hierarchy and autonomous actions. It is possible to engineer these essential elements into clinical biomaterials via bioinspired implementation of concepts, processes and mechanisms played out during Darwinian evolution; mechanisms such as, directed, computational, accelerated evolutions and artificial selection contrived in the laboratory. These dynamos for innovation can be used during biomaterials fabrication, but also to choose optimal designs in the regeneration process. Further evolutionary information can help at the design stage; gleaned from the historical evolution of material adaptations compared across phylogenies to changes in their environment and habitats. Taken together, harnessing evolutionary mechanisms and evolutionary pathways, leading to ideal adaptations, will eventually provide a new class of Darwinian and evolutionary biomaterials. This will provide bioengineers with a more diversified and more efficient innovation tool for biomaterial design, synthesis and function than currently achieved with synthetic materials chemistry programmes and rational based materials design approach, which require reasoned logic. It will also inject further creativity, diversity and richness into the biomedical technologies that we make. All of which are based on biological principles. Such evolution-inspired biomaterials have the potential to generate innovative solutions, which match with existing bioengineering problems, in vital areas of clinical materials translation that include tissue engineering, gene delivery, drug delivery, immunity modulation, and scar-less wound healing. STATEMENT OF SIGNIFICANCE: Evolution by natural selection is a powerful generator of innovations in molecular, materials and structures. Man has influenced evolution for thousands of years, to create new breeds of farm animals and crop plants, but now molecular and materials can be molded in the same way. Biological molecules and simple structures can be evolved, literally in the laboratory. Furthermore, they are re-designed via lessons learnt from evolutionary history. Through a 3-step process to (1) create variants in material building blocks, (2) screen the variants with beneficial traits/properties and (3) select and support their self-assembly into usable materials, improvements in design and performance can emerge. By introducing biological molecules and small organisms into this process, it is possible to make increasingly diversified, sophisticated and clinically relevant materials for multiple roles in biomedicine.

People with Parkinson's disease and normal MMSE score have a broad range of cognitive performance.

Cognitive impairment, including dementia, is common in Parkinson's disease (PD). The Mini-Mental State Examination (MMSE) has been recommended as a screening tool for Parkinson's disease dementia (PDD), with values below 26 indicative of possible dementia. Using a detailed neuropsychological battery, we examined the range of cognitive impairment in PD patients with an MMSE score of 26 or higher. In this multicenter, cross-sectional, observational study, we performed neuropsychological testing in a sample of 788 PD patients with MMSE scores of 26 or higher. Evaluation included tests of global cognition, executive function, language, memory, and visuospatial skills. A consensus panel reviewed results for 342 subjects and assigned a diagnosis of no cognitive impairment, mild cognitive impairment, or dementia. Sixty-seven percent of the 788 subjects performed 1.5 standard deviations below the normative mean on at least one test. On eight of the 15 tests, more than 20% of subjects scored 1.5 standard deviations or more below the normative mean. Greatest impairments were found on Hopkins Verbal Learning and Digit Symbol Coding tests. The sensitivity of the MMSE to detect dementia was 45% in a subset of participants who underwent clinical diagnostic procedures. A remarkably wide range of cognitive impairment can be found in PD patients with a relatively high score on the MMSE, including a level of cognitive impairment consistent with dementia. Given these findings, clinicians must be aware of the limitations of the MMSE in detecting cognitive impairment, including dementia, in PD.

Intranasal insulin improves cognition and modulates beta-amyloid in early AD.

BACKGROUND: Reduced brain insulin signaling and low CSF-to-plasma insulin ratios have been observed in patients with Alzheimer disease (AD). Furthermore, intracerebroventricular or IV insulin administration improve memory, alter evoked potentials, and modulate neurotransmitters, possibly by augmenting low brain levels. After intranasal administration, insulin-like peptides follow extracellular pathways to the brain within 15 minutes. OBJECTIVE: We tested the hypothesis that daily intranasal insulin treatment would facilitate cognition in patients with early AD or its prodrome, amnestic mild cognitive impairment (MCI). The proportion of verbal information retained after a delay period was the planned primary outcome measure. Secondary outcome measures included attention, caregiver rating of functional status, and plasma levels of insulin, glucose, beta-amyloid, and cortisol. METHODS: Twenty-five participants were randomly assigned to receive either placebo (n = 12) or 20 IU BID intranasal insulin treatment (n = 13) using an electronic atomizer, and 24 participants completed the study. Participants, caregivers, and all clinical evaluators were blinded to treatment assignment. Cognitive measures and blood were obtained at baseline and after 21 days of treatment. RESULTS: Fasting plasma glucose and insulin were unchanged with treatment. The insulin-treated group retained more verbal information after a delay compared with the placebo-assigned group (p = 0.0374). Insulin-treated subjects also showed improved attention (p = 0.0108) and functional status (p = 0.0410). Insulin treatment raised fasting plasma concentrations of the short form of the beta-amyloid peptide (A beta 40; p = 0.0471) without affecting the longer isoform (A beta 42), resulting in an increased A beta 40/42 ratio (p = 0.0207). CONCLUSIONS: The results of this pilot study support further investigation of the benefits of intranasal insulin for patients with Alzheimer disease, and suggest that intranasal peptide administration may be a novel approach to the treatment of neurodegenerative disorders.

Differential modulation of plasma beta-amyloid by insulin in patients with Alzheimer disease.

BACKGROUND: Hyperinsulinemia and insulin resistance are risk factors for memory impairment and Alzheimer disease (AD). Insulin regulates levels of the amyloid beta-peptide (Abeta) in vitro in neuronal cultures and in vivo in the CSF of normal older adults. OBJECTIVE: To determine whether insulin affected plasma Abeta levels and whether such effects differed for patients with AD compared with normal older adults. METHODS: Fifty-nine patients with AD and 50 healthy older adults each received infusions of saline and of insulin (1.0 mU.kg(-1).min(-1)) with accompanying dextrose to maintain euglycemia. A subset of participants (19 AD, 12 normal) received two additional conditions, in which insulin was infused at a lower (0.33 mU.kg(-1).min(-1)) and higher (1.67 mU.kg(-1).min(-1)) rate. Plasma insulin and Abeta were measured after 120 minutes of infusion. RESULTS: Adults with AD had higher plasma insulin vs normal adults at the two higher infusion rates, despite receiving comparable amounts of insulin. For normal adults, insulin reduced plasma Abeta levels at the middle (1.0 mU.kg(-1).min(-1)) dose, with attenuated effects at lower and higher doses. In contrast, for patients with AD, insulin raised plasma Abeta levels at the two higher doses (1.0 and 1.67 mU.kg(-1).min(-1)). CONCLUSIONS: These results suggest that patients with Alzheimer disease (AD) have reduced insulin clearance and insulin-provoked plasma amyloid beta-peptide (Abeta) elevation. Abnormal regulation of peripheral Abeta by insulin may contribute to AD risk.

Two-dimensional stick-slip on a soft elastic polymer: pattern generation using atomic force microscopy.

It has been demonstrated that it is possible to create laterally differentiated frictional patterning and three-dimensional structures using an atomic force microscope (AFM) probe on the surface of a soft elastic polymer, poly(dimethylsiloxane) (PDMS). The resulting effect of contact mode imaging at low loading forces (<100 nN), observed in the lateral force mode, revealed a homogeneous pattern on the PDMS surface exhibiting higher friction. With higher loading forces ([Formula: see text] nN) the effect is non-uniform, resulting in structures with depths on the nanometre scale. The topographic and frictional data revealed stick-slip responses in both the fast (orthogonal to the long axis of the lever) and slow (parallel to the long axis of the lever) directions of probe travel from scanning in a raster pattern. The stick-slip events are manifested in the form of a series of shallow channels spaced evenly apart on the polymer surface. Detailed friction loop analysis acquired during the manipulation process showed that the lateral force changed according to the strength of trapping of the tip with the polymer surface exhibiting significant in-plane deformation due to lateral forces being imposed. An incremental increase in the initial loading force resulted in an increase in in-plane displacement and a greater spacing between the stick lines/channels in the slow-scan direction. A decrease in channel length in the fast-scan direction is also observed as a result of an increase in static friction with normal force, resulting in greater surface deformation and shorter track length for sliding friction.

Effects of intranasal insulin on cognition in memory-impaired older adults: modulation by APOE genotype.

Raising insulin acutely in the periphery and in brain improves verbal memory. Intranasal insulin administration, which raises insulin acutely in the CNS without raising plasma insulin levels, provides an opportunity to determine whether these effects are mediated by central insulin or peripheral processes. Based on prior research with intravenous insulin, we predicted that the treatment response would differ between subjects with (epsilon4+) and without (epsilon4-) the APOE-epsilon4 allele. On separate mornings, 26 memory-impaired subjects (13 with early Alzheimer's disease and 13 with amnestic mild cognitive impairment) and 35 normal controls each underwent three intranasal treatment conditions consisting of saline (placebo) or insulin (20 or 40 IU). Cognition was tested 15 min post-treatment, and blood was acquired at baseline and 45 min after treatment. Intranasal insulin treatment did not change plasma insulin or glucose levels. Insulin treatment facilitated recall on two measures of verbal memory in memory-impaired epsilon4- adults. These effects were stronger for memory-impaired epsilon4- subjects than for memory-impaired epsilon4+ subjects and normal adults. Unexpectedly, memory-impaired epsilon4+ subjects showed poorer recall following insulin administration on one test of memory. These findings suggest that intranasal insulin administration may have therapeutic benefit without the risk of peripheral hypoglycemia and provide further evidence for apolipoprotein E (APOE) related differences in insulin metabolism.

Hierarchy of DNA immobilization and hybridization on poly-L-lysine using an atomic force microscopy study.

The atomic force microscopy has been used to analyze the immobilization of single stranded DNA on poly-L-lysine-coated glass and subsequent hybridization with complimentary DNA with the Z-threshold parameter and fractal analysis methods. The poly-L-lysine layer, which has a thickness of approximately 7 nm, presents nano-defects that could be critical for DNA immobilization by acting as a nucleation sites for ssDNA and subsequently for dsDNA aggregates. The Z-threshold for the dsDNA aggregates is much larger than for ssDNA, but the statistical fractal dimension is very similar, suggesting a conformal increase of the dimensions of the dsDNA aggregates mainly in the Z-direction, due to an effective ssDNA-ccDNA molecular recognition. This study demonstrates the use of fractal analysis in conjunction with the distribution of heights to evaluate the efficiency of DNA-DNA molecular recognition on surfaces and the impact of nanodefects.

Effects of beta-hydroxybutyrate on cognition in memory-impaired adults.

Glucose is the brain's principal energy substrate. In Alzheimer's disease (AD), there appears to be a pathological decrease in the brain's ability to use glucose. Neurobiological evidence suggests that ketone bodies are an effective alternative energy substrate for the brain. Elevation of plasma ketone body levels through an oral dose of medium chain triglycerides (MCTs) may improve cognitive functioning in older adults with memory disorders. On separate days, 20 subjects with AD or mild cognitive impairment consumed a drink containing emulsified MCTs or placebo. Significant increases in levels of the ketone body beta-hydroxybutyrate (beta-OHB) were observed 90 min after treatment (P=0.007) when cognitive tests were administered. beta-OHB elevations were moderated by apolipoprotein E (APOE) genotype (P=0.036). For 4+ subjects, beta-OHB levels continued to rise between the 90 and 120 min blood draws in the treatment condition, while the beta-OHB levels of 4- subjects held constant (P<0.009). On cognitive testing, MCT treatment facilitated performance on the Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-cog) for 4- subjects, but not for 4+ subjects (P=0.04). Higher ketone values were associated with greater improvement in paragraph recall with MCT treatment relative to placebo across all subjects (P=0.02). Additional research is warranted to determine the therapeutic benefits of MCTs for patients with AD and how APOE-4 status may mediate beta-OHB efficacy.

Interactions of poly(amino acids) in aqueous solution with charged model surfaces--analysis by colloidal probe.

Biomolecules in a confined solution environment may be subject to electrostatic forces with a range up to 100 nm, while van der Waals interaction will account for shorter-range forces. The response of two model poly(amino acids)--poly-L-lysine and poly-L-glutamic acid--has been investigated for a silica/Si-oxide surface at pH 6. The model amino acids were adsorbed, or covalently coupled, to colloidal probes consisting of a microsphere attached to a force-sensing lever. The methodology was based on sensing interaction between the probe and a flat surface through carrying out force versus distance analysis with a scanning force microscope. The results were analyzed within the framework of the conventional DLVO theory. The outcomes illustrate both repulsive and attractive long-range interactions that will hinder, or promote, colloidal biospecies in solution entering the region of attractive short-range interactions at the physical interface. Large 'snap-on' distances were observed for some systems and have been ascribed to compression of the 'soft' functionalized layers. Those observations and measurements of adhesion provided insight into conformation of the adsorbed species and strength of attachment. The results have implications for the efficacy of methods and devices that seek to exploit the properties of micro/nano-fluidic systems.

Insulin increases CSF Abeta42 levels in normal older adults.

BACKGROUND: Abnormal insulin metabolism may contribute to the clinical symptoms and pathophysiology of AD. In vitro studies show that insulin enhances the release of beta-amyloid protein (Abeta) or inhibits its degradation, either of which might increase amyloid burden. METHODS: On separate mornings, 16 healthy older adults (10 women, 6 men; mean age 68.7 years, SD 8.6 years) each underwent two infusions consisting of either saline (placebo) or insulin (1.0 mU x kg(-1) x min(-1)) plus dextrose to maintain euglycemia. After 120 minutes of infusion, blood, CSF, and cognitive measures were acquired. RESULTS: As expected, insulin infusion produced an increase in CSF insulin concentration. Insulin infusion also led to an increase in CSF Abeta42 levels, most notably in older subjects. As has been observed previously, insulin infusion facilitated declarative memory, but such facilitation was attenuated in the subjects with the greatest increase in CSF Abeta42 levels. CONCLUSIONS: These findings are consistent with recent in vitro studies of insulin effects on Abeta and support the notion that insulin may modulate Abeta42 levels acutely in humans.

Effects of fexofenadine, diphenhydramine, and alcohol on driving performance. A randomized, placebo-controlled trial in the Iowa driving simulator.

BACKGROUND: Sedating antihistamines may impair driving performance as seriously as alcohol. OBJECTIVE: To compare the effects of fexofenadine, diphenhydramine, alcohol, and placebo on driving performance. DESIGN: Randomized, double-blind, double-dummy, four-treatment, four-period crossover trial. SETTING: The Iowa Driving Simulator. PARTICIPANTS: 40 licensed drivers with seasonal allergic rhinitis who were 25 to 44 years of age. INTERVENTION: One dose of fexofenadine (60 mg), diphenhydramine (50 mg), alcohol (approximately 0.1% blood alcohol concentration), or placebo, given at weekly intervals before participants drove for 1 hour in the Iowa Driving Simulator. MEASUREMENTS: The primary end point was coherence, a continuous measure of participants' ability to match the varying speed of a vehicle that they were following. Secondary end points were drowsiness and other driving measures, including lane keeping and response to a vehicle that unexpectedly blocked the lane ahead. RESULTS: Participants had significantly better coherence after taking alcohol or fexofenadine than after taking diphenhydramine. Lane keeping (steering instability and crossing the center line) was impaired after alcohol and diphenhydramine use compared with fexofenadine use. Mean response time to the blocking vehicle was slowest after alcohol use (2.21 seconds) compared with fexofenadine use (1.95 seconds). Self-reported drowsiness did not predict lack of coherence and was weakly associated with minimum following distance, steering instability, and leftlane excursion. CONCLUSIONS: Participants had similar performance when treated with fexofenadine or placebo. After alcohol use, participants performed the primary task well but not the secondary tasks; as a result, overall driving performance was poorer. After participants took diphenhydramine, driving performance was poorest, indicating that diphenhydramine had a greater impact on driving than alcohol did. Drowsiness ratings were not a good predictor of impairment, suggesting that drivers cannot use drowsiness to indicate when they should not drive.

Imaging and force-distance analysis of human fibroblasts in vitro by atomic force microscopy.

The structure of human fibroblasts have been characterised in vitro by atomic force microscopy (AFM) operated in the imaging or in the force versus distance (F-d) modes. The choice of cell substrate is important to ensure good adhesion. Of greater significance in the context of AFM analysis, is the observation that the substrate affects the imaging conditions for in vitro analysis of live cells. For instance, very rarely will glass coverslips lead to acceptable outcomes (i.e., resolved cytoskeletal structure). Activated tissue culture dishes, on the other hand, promote conditions that routinely result in good quality images. Those conditions are then unaffected by adoption of relatively high force loadings (more than 10 nN), large fields of view (100 x 100 microm2) and high scan speeds (up to ca. 200 microm/sec), all of which exceed values recommended in the literature. Plasma membranes are fragile in the context of AFM analysis (F-d analysis gives an equivalent Young's Modulus of ca. 5 kPa). However, the present work suggests that fragility per se need not be a problem, rather it is the adhesive interactions with the tip, which under some circumstances may exceed 20 nN, that are the source of poor imaging conditions. The present results, being supported by a qualitative model, suggest that the activated substrate acts as a preferential scavenger of cellular debris thus preventing the tip from biofouling, and will therefore promote low adhesion between tip and membrane. Good imaging conditions provide non-destructive in vitro information about cytoskeletal structure and dynamics, as shown in two examples concerned with cytochalasin treatment and with the MTT assay.

Benzodiazepine receptor function in the chick social separation-stress procedure.

The role of benzodiazepine (BZ) receptors in modulating social separation-induced distress vocalizations (DVocs) and stress-induced analgesia (SIA) were examined in 8-day-old cockerels (Gallus gallus). In Experiment 1, the BZ agonist chlordiazepoxide (CDP; 5.0 mg/kg) reversed both DVocs and SIA in isolated chicks. Coadministration of the BZ antagonist flumazenil (0.01, 0.03, or 0.10 mg/kg) reversed CDP anxiolytic effects. In Experiment 2, the BZ agonists alprazolam (ALP; 0.065, 0.125, 0.25, or 1.50 mg/kg) and lorazepam (LOR; 0.125, 0.25, 0.50, or 1.0 mg/kg) dose dependently reversed social separation-induced DVocs and SIA. The ED50s for ALP and LOR in attenuating DVocs were 0.19 and 0.34 mg/kg, respectively. These data strongly support the theory that CDP anxiolytic effects are mediated by BZ receptor activity in the chick social separation procedure (Experiment 1) and that this model is sensitive to BZ agonists of different potencies (Experiment 2).

Handedness, footedness, and language laterality: evidence from Wada testing.

A total of 37 candidates for temporal lobe resection for epilepsy completed the Lateral Dominance Examination, a self-report instrument that measures hand and foot preference. Questionnaire results were compared with speech dominance, which had been determined by Intracarotid Sodium Amytal Procedure. Footedness was as good as handedness as a predictor of language laterality.

Optimal scoring strategies and weights for the formalin test in rats.

The formalin test is a well-established model for assessing inflammatory nociceptive processes and analgesic drug effects. Previous research established the validity of an ordinal relationship among three well-defined pain behavior categories used to compute a composite pain score (CPS). However, optimal weights had not been validated. The present research used data from Coderre et al. (1993) and from Sufka and Roach (1996) to determine and validate optimal pain behavior category weights. Based on multiple regression analyses and Pearson correlations, optimal weights of 1 and 2 are proposed for behavior categories 2 and 3, respectively; behavior category 1 is not scored. These results are consistent with the work of Abbott et al. (1995) and Coderre et al. (1993) in that the ordinal relationship among category weights is preserved, and extend previous work by establishing optimal category weights.

Buschke-Lewenstein tumour of the penis. A case report.

A 30 year old man presented with a large, penile, warty growth. The histopathological features were consistent with giant condylomata acuminata. After successful treatment with 5-fluorouracil cream and electrocautery some growth recurred at the excision site. Subtotal amputation of the penis was performed to remove the warty base. Because of the infective component of giant condylomata acuminata patients as well as their wives should be examined regularly.