TiO2 nanorod arrays@PDA/Ag with biomimetic polydopamine as binary mediators for duplex SERS detection of illegal food dyes

Based on TiO2 nanorod arrays@PDA/Ag (TNRs@PDA/Ag), a better surface-enhanced Raman scattering (SERS) sensor with effective enrichment and enhancement was investigated for duplex SERS detection of illicit food dyes. Biomimetic PDA functions as binary mediators by utilizing the structural characteristics of polydopamine (PDA), which include the conjugated structure and abundant hydrophilic groups. One PDA functioned as an electron transfer mediator to enhance the efficiency of electron transfer, and the other as an enrichment mediator to effectively enrich rhodamine B (RhB) and crystal violet (CV) through hydrogen bonding, π-π stacking, and electrostatic interactions. Individual and duplex detection of illicit food dyes (RhB and CV) was performed using TNRs@PDA/Ag to estimate SERS applications. Their linear equations and limits of detection of 1 nM for RhB and 5 nM for CV were derived. Individual and duplex food colour detection was successfully accomplished even in genuine chili meal with good results. The bifunctional TNRs@PDA/Ag-based highly sensitive and duplex SERS dye detection will have enormous potential for food safety monitoring.

Clinical presentation, treatment, and genetic and histopathological analysis of juvenile cataracts and secondary glaucoma in a rhesus macaque (Macaca mulatta)

This report describes the clinical and histological findings, genetic study, and treatment in a 1.3-year-old rhesus macaque with bilateral cataracts and unilateral secondary glaucoma. Intravitreal injection of gentamicin decreased the intraocular pressure from 56 to <2 mm Hg. A putative genetic cause of the cataracts was not identified.

Neuropeptide S receptor 1 is a nonhormonal treatment target in endometriosis

Endometriosis is a common chronic inflammatory condition causing pelvic pain and infertility in women, with limited treatment options and 50% heritability. We leveraged genetic analyses in two species with spontaneous endometriosis, humans and the rhesus macaque, to uncover treatment targets. We sequenced DNA from 32 human families contributing to a genetic linkage signal on chromosome 7p13-15 and observed significant overrepresentation of predicted deleterious low-frequency coding variants in NPSR1, the gene encoding neuropeptide S receptor 1, in cases (predominantly stage III/IV) versus controls (P = 7.8 × 10^-4). Significant linkage to the region orthologous to human 7p13-15 was replicated in a pedigree of 849 rhesus macaques (P = 0.0095). Targeted association analyses in 3194 surgically confirmed, unrelated cases and 7060 controls revealed that a common insertion/deletion variant, rs142885915, was significantly associated with stage III/IV endometriosis (P = 5.2 × 10^-5; odds ratio, 1.23; 95% CI, 1.09 to 1.39). Immunohistochemistry, qRT-PCR, and flow cytometry experiments demonstrated that NPSR1 was expressed in glandular epithelium from eutopic and ectopic endometrium, and on monocytes in peritoneal fluid. The NPSR1 inhibitor SHA 68R blocked NPSR1-mediated signaling, proinflammatory TNF-α release, and monocyte chemotaxis in vitro (P < 0.01), and led to a significant reduction of inflammatory cell infiltrate and abdominal pain (P < 0.05) in a mouse model of peritoneal inflammation as well as in a mouse model of endometriosis. We conclude that the NPSR1/NPS system is a genetically validated, nonhormonal target for the treatment of endometriosis with likely increased relevance to stage III/IV disease.

Role of toll-like receptor 7 (TLR7) in voluntary alcohol consumption

Overactivation of neuroimmune signaling has been linked to excessive ethanol consumption. Toll-like receptors (TLRs) are a major component of innate immune signaling and initiate anti- and pro-inflammatory responses via intracellular signal transduction cascades. TLR7 is upregulated in post-mortem brain tissue from humans with alcohol use disorder (AUD) and animals with prior exposure to ethanol. Despite this evidence, the role of TLR7 in the regulation of voluntary ethanol consumption has not been studied. We test the hypothesis that TLR7 activation regulates voluntary ethanol drinking behavior by administering a TLR7 agonist (R848) during an intermittent access drinking procedure in mice. Acute activation of TLR7 reduced ethanol intake, preference, and total fluid intake due, at least in part, to an acute sickness response. However, chronic pre-treatment with R848 resulted in tolerance to the adverse effects of the drug and a subsequent increase in ethanol consumption. To determine the molecular machinery that mediates these behavioral changes, we evaluated gene expression after acute and chronic TLR7 activation. We found that acute TLR7 activation produces brain region specific changes in expression of immune pathway genes, whereas chronic TLR7 activation causes downregulation of TLRs and blunted cytokine induction, suggesting molecular tolerance. Our results demonstrate a novel role for TLR7 signaling in regulating voluntary ethanol consumption. Taken together, our findings suggest TLR7 may be a viable target for development of therapies to treat AUD.

Population-Based Estimation of the Preterm Birth Rate in Lilongwe, Malawi: Making Every Birth Count

Objective  The objective of this study was to perform a population-based estimation of the preterm birth (PTB) rate in regions surrounding Lilongwe, Malawi. Study Design  We partnered with obstetrician specialists, community health workers, local midwives, and clinicians in a 50 km region surrounding Lilongwe, Malawi, to perform a population-based estimation of the PTB rate during the study period from December 1, 2012 to May 19, 2015. Results  Of the 14,792 births captured, 19.3% of births were preterm, including preterm early neonatal deaths. Additional PTB risk factors were similarly prevalent including domestic violence, HIV, malaria, anemia, and malnutrition. Conclusion  When performing a population-based estimation of the rate of PTB, including women without antenatal care and women delivering at home, the 19.3% rate of PTB is among the highest recorded globally. This is accompanied by a high rate of risk factors and comorbid conditions.

Associations between muscle mass, physical activity and dietary behaviour in adolescents

BACKGROUND AND OBJECTIVES

Investigations in older individuals suggest that adequate nutrition and physical activity are particularly important to skeletal muscle health; however, data in adolescents are scant and equivocal. The objective was to determine the associations among diet, physical activity and skeletal muscle mass in adolescents.

METHODS

We assessed diet with four to seven 24-h recalls and physical activity by accelerometry in 640 adolescents. Using total body measures of fat-free soft tissue mass and fat mass assessed by dual-energy X-ray absorptiometry, the skeletal muscle mass index (SMMI) was derived by adjusting fat-free soft tissue mass for fat mass in addition to height.

RESULTS

Skeletal muscle mass index (SMMI) was negatively associated with consumption of sugar-sweetened beverages (standardized beta coefficient [β] = -0.10, P = 0.001) and saturated fats (β = -0.28, P < 0.001). SMMI was positively associated with physical activity (moderate + vigorous) (β = 0.20, P < 0.001). In further analysis, we observed a significant interaction between physical activity and sugar-sweetened beverage intake on SMMI (P = 0.002).

CONCLUSION

Our study in adolescence suggests that physical activity and consumption of both sugar-sweetened beverages and saturated fats are associated with skeletal muscle mass. More importantly, our findings suggest that sugar-sweetened beverage intake may attenuate the beneficial effects of physical activity on skeletal muscle mass.

Maresin 1 attenuates neuroinflammation in a mouse model of perioperative neurocognitive disorders

Background

Resolution of inflammation is an active and dynamic process after surgery. Maresin 1 (MaR1) is one of a growing number of specialised pro-resolving lipids biosynthesised by macrophages that regulates acute inflammation. We investigated the effects of MaR1 on postoperative neuroinflammation, macrophage activity, and cognitive function in mice.

Methods

Adult male C57BL/6 (n=111) and Ccr2^RFP/+Cx3cr1^GFP/+ (n=54) mice were treated with MaR1 before undergoing anaesthesia and orthopaedic surgery. Systemic inflammatory changes, bone healing, neuroinflammation, and cognition were assessed at different time points. MaR1 protective effects were also evaluated using bone marrow derived macrophage cultures.

Results

MaR1 exerted potent systemic anti-inflammatory effects without impairing fracture healing. Prophylaxis with MaR1 prevented surgery-induced glial activation and opening of the blood–brain barrier. In Ccr2^RFP/+Cx3cr1^GFP/+ mice, fewer infiltrating macrophages were detected in the hippocampus after surgery with MaR1 prophylaxis, which resulted in improved memory function. MaR1 treatment also reduced expression of pro-inflammatory cell surface markers and cytokines by in vitro cultured macrophages. MaR1 was detectable in the cerebrospinal fluid of older adults before and after surgery.

Conclusions

MaR1 exerts distinct anti-inflammatory and pro-resolving effects through regulation of macrophage infiltration, NF-κB signalling, and cytokine release after surgery. Future studies on the use of pro-resolving lipid mediators may inform novel approaches to treat neuroinflammation and postoperative neurocognitive disorders.

Neuroimmune signaling in alcohol use disorder

Alcohol use disorder (AUD) is a widespread disease with limited treatment options. Targeting the neuroimmune system is a new avenue for developing or repurposing effective pharmacotherapies. Alcohol modulates innate immune signaling in different cell types in the brain by altering gene expression and the molecular pathways that regulate neuroinflammation. Chronic alcohol abuse may cause an imbalance in neuroimmune function, resulting in prolonged perturbations in brain function. Likewise, manipulating the neuroimmune system may change alcohol-related behaviors. Psychiatric disorders that are comorbid with AUD, such as post-traumatic stress disorder, major depressive disorder, and other substance use disorders, may also have underlying neuroimmune mechanisms; current evidence suggests that convergent immune pathways may be involved in AUD and in these comorbid disorders. In this review, we provide an overview of major neuroimmune cell-types and pathways involved in mediating alcohol behaviors, discuss potential mechanisms of alcohol-induced neuroimmune activation, and present recent clinical evidence for candidate immune-related drugs to treat AUD.

Standardization of a Videofluoroscopic Swallow Study Protocol to Investigate Dysphagia in Dogs

Background

Videofluoroscopic swallow study (VFSS) is the gold standard for diagnosis of dysphagia in veterinary medicine but lacks standardized protocols that emulate physiologic feeding practices. Age impacts swallow function in humans but has not been evaluated by VFSS in dogs.

Hypothesis/Objectives

To develop a protocol with custom kennels designed to allow free‐feeding of 3 optimized formulations of contrast media and diets that address limitations of current VFSS protocols. We hypothesized that dogs evaluated by a free‐feeding VFSS protocol would show differences in objective swallow metrics based on age.

Animals

Healthy juvenile, adult, and geriatric dogs (n = 24).

Methods

Prospective, experimental study. Custom kennels were developed to maintain natural feeding behaviors during VFSS. Three food consistencies (thin liquid, pureed food, and dry kibble) were formulated with either iohexol or barium to maximize palatability and voluntary prehension. Dogs were evaluated by 16 swallow metrics and compared across age groups.

Results

Development of a standardized VFSS protocol resulted in successful collection of swallow data in healthy dogs. No significant differences in swallow metrics were observed among age groups. Substantial variability was observed in healthy dogs when evaluated under these physiologic conditions. Features typically attributed to pathologic states, such as gastric reflux, were seen in healthy dogs.

Conclusions and Clinical Importance

Development of a VFSS protocol that reflects natural feeding practices may allow emulation of physiology resulting in clinical signs of dysphagia. Age did not result in significant changes in swallow metrics, but additional studies are needed, particularly in light of substantial normal variation.

Eating and arterial endothelial function: a meta-analysis of the acute effects of meal consumption on flow-mediated dilation

Given that endothelial dysfunction precedes atherosclerotic cardiovascular disease, exploring the parameters that modify postprandial flow-mediated dilation (FMD) is important for public health. The objectives of the study are to estimate the population effect of meal ingestion on FMD and to determine how the effect varied based on patient characteristics and modifiable methodological features. Articles published before June 2015 were located using MEDLINE, PubMed and Web of Science. One hundred fifty-four effects were derived from 78 articles involving 2,548 subjects were selected. Included articles required measurement of FMD in adults before and after meal ingestion. Effects were analysed using an unstandardized mean gain random effects model, and significant moderators were analysed using meta-regression. Meal consumption significantly reduced FMD by a heterogeneous mean effect size delta (Δ) of -2.03 (95% CI: [-2.28, -1.77]), an ~2% reduction in FMD. FMD reductions were larger among normal weight individuals, males, those with a cardio-metabolic disorder, those with elevated baseline FMD, and individuals with impaired glucose tolerance at baseline. Macronutrient meal ingestion significantly reduced FMD, an effect that was moderated by body mass index, sex and two-way interactions between disease status and both baseline FMD and baseline blood glucose levels.

Synthesis, characterization and multifunctional properties of plasmonic Ag-TiO2 nanocomposites

We report on the synthesis of multifunctional Ag-TiO2 nanocomposites and their optical, physio-chemical, surface enhanced Raman scattering (SERS) and antibacterial properties. A series of Ag-TiO2 nanocomposites were synthesized by sol-gel technique and characterized by x-ray diffraction, scanning and transmission electron microscopy, energy-dispersed x-ray analysis, photoluminescence, UV-vis, x-ray photoelectron and Raman spectroscopy and Brunauer-Emmett-Teller method. The Ag nanoparticles (NPs) (7-20 nm) were found to be uniformly distributed around and strongly attached to TiO2 NPs. The novel optical responses of the nanocomposites are due to the strong electric field from the localized surface plasmon (LSP) excitation of the Ag NPs and decreased recombination of photo-induced electrons and holes at Ag-TiO2 interface providing potential materials for photocatalysis. The nanocomposites show enhancement in the SERS signals of methyl orange (MO) molecules with increasing Ag content attributed to the long-range electromagnetic enhancement from the excited LSP of the Ag NPs. To further understand the SERS activity, molecular mechanics and molecular dynamics simulations were used to study the geometries and SERS enhancement of MO adsorbed onto Ag-TiO2 respectively. Simulation results indicate that number of ligands (MO) that adsorb onto the Ag NPs as well as binding energy per ligand increases with increasing NP density and molecule-to-surface orientation is mainly flat resulting in strong bond strength between MO and Ag NP surface and enhanced SERS signals. The antimicrobial activity of the Ag-TiO2 nanocomposites was tested against the bacterium Staphylococcus aureus and enhanced antibacterial effect was observed with increasing Ag content explained by contact killing action mechanism. These results foresee promising applications of the plasmonic metal-semiconductor based nano-biocomposites for both chemical and biological samples.

Altered regulatory T cell phenotype in latent autoimmune diabetes of the adults (LADA)

Latent autoimmune diabetes of the adults (LADA) accounts for up to 12% of all patients with diabetes. Initially the disease resembles type 2 diabetes (T2D); however, the typical presence of β cell autoantibodies indicates an autoimmune basis of LADA. While dysfunctional regulatory T cells (Tregs ) have been implicated in autoimmune diabetes, these cells have been scarcely studied in LADA. The aim of this study was to investigate the frequency and phenotype of circulating Tregs in LADA patients early during disease progression. Flow cytometric analysis was performed on whole blood and peripheral mononuclear cells (PBMC) from patients diagnosed with LADA prior to insulin deficiency (n = 39) and from healthy volunteers (n = 20). Overall, we found the frequency and activation status of peripheral putative Tregs to be altered in LADA patients compared to healthy controls. While total T cells and CD4(+) T cells expressing high levels of CD25 (CD4(+) CD25(hi) ) were unchanged, the frequency and total numbers of CD4(+) T cells expressing an intermediate level of CD25 (CD4(+) CD25(int) ) were decreased in LADA patients. Interestingly, the expression of the Treg -specific marker forkhead box protein 3 (FoxP3), as well as the activation and memory makers CD69, cytotoxic T lymphocyte associated antigen 4 (CTLA-4), CCR4 and CD45RO were increased in CD4(+) CD25(+) T cells of the patients. Our data depict phenotypical changes in T cells of LADA patients that may reflect a derangement in peripheral immune regulation contributing to the slow process leading to insulin-dependent diabetes in these patients.

Customisable 3D printed microfluidics for integrated analysis and optimisation

The formation of smart Lab-on-a-Chip (LOC) devices featuring integrated sensing optics is currently hindered by convoluted and expensive manufacturing procedures. In this work, a series of 3D-printed LOC devices were designed and manufactured via stereolithography (SL) in a matter of hours. The spectroscopic performance of a variety of optical fibre combinations were tested, and the optimum path length for performing Ultraviolet-visible (UV-vis) spectroscopy determined. The information gained in these trials was then used in a reaction optimisation for the formation of carvone semicarbazone. The production of high resolution surface channels (100-500 μm) means that these devices were capable of handling a wide range of concentrations (9 μM-38 mM), and are ideally suited to both analyte detection and process optimisation. This ability to tailor the chip design and its integrated features as a direct result of the reaction being assessed, at such a low time and cost penalty greatly increases the user's ability to optimise both their device and reaction. As a result of the information gained in this investigation, we are able to report the first instance of a 3D-printed LOC device with fully integrated, in-line monitoring capabilities via the use of embedded optical fibres capable of performing UV-vis spectroscopy directly inside micro channels.

Genes and Alcohol Consumption: Studies with Mutant Mice

In this chapter, we review the effects of global null mutant and overexpressing transgenic mouse lines on voluntary self-administration of alcohol. We examine approximately 200 publications pertaining to the effects of 155 mouse genes on alcohol consumption in different drinking models. The targeted genes vary in function and include neurotransmitter, ion channel, neuroimmune, and neuropeptide signaling systems. The alcohol self-administration models include operant conditioning, two- and four-bottle choice continuous and intermittent access, drinking in the dark limited access, chronic intermittent ethanol, and scheduled high alcohol consumption tests. Comparisons of different drinking models using the same mutant mice are potentially the most informative, and we will highlight those examples. More mutants have been tested for continuous two-bottle choice consumption than any other test; of the 137 mouse genes examined using this model, 97 (72%) altered drinking in at least one sex. Overall, the effects of genetic manipulations on alcohol drinking often depend on the sex of the mice, alcohol concentration and time of access, genetic background, as well as the drinking test.

Alcohol consumption induces global gene expression changes in VTA dopaminergic neurons

Alcoholism is associated with dysregulation in the neural circuitry that mediates motivated and goal-directed behaviors. The dopaminergic (DA) connection between the ventral tegmental area (VTA) and the nucleus accumbens is viewed as a critical component of the neurocircuitry mediating alcohol's rewarding and behavioral effects. We sought to determine the effects of binge alcohol drinking on global gene expression in VTA DA neurons. Alcohol-preferring C57BL/6J × FVB/NJ F1 hybrid female mice were exposed to a modified drinking in the dark (DID) procedure for 3 weeks, while control animals had access to water only. Global gene expression of laser-captured tyrosine hydroxylase (TH)-positive VTA DA neurons was measured using microarrays. A total of 644 transcripts were differentially expressed between the drinking and nondrinking mice, and 930 transcripts correlated with alcohol intake during the last 2 days of drinking in the alcohol group. Bioinformatics analysis of alcohol-responsive genes identified molecular pathways and networks perturbed in DA neurons by alcohol consumption, which included neuroimmune and epigenetic functions, alcohol metabolism and brain disorders. The majority of genes with high and specific expression in DA neurons were downregulated by or negatively correlated with alcohol consumption, suggesting a decreased activity of DA neurons in high drinking animals. These changes in the DA transcriptome provide a foundation for alcohol-induced neuroadaptations that may play a crucial role in the transition to addiction.

Fibroblast growth factor 21 analogue LY2405319 lowers blood glucose in streptozotocin-induced insulin-deficient diabetic mice by restoring brown adipose tissue function

AIM

To investigate the effects of LY2405319, an analogue of fibroblast growth factor 21 (FGF21), on glucose homeostasis in streptozotocin (STZ)-induced insulin-deficient mice (STZ mice).

METHODS

Nine-week-old male C57BL/6J mice were administered a single intraperitoneal injection of STZ (150 mg/kg). One week later, after confirmation of hyperglycaemia, saline or LY2405319 (5 mg/kg) was injected subcutaneously daily for 4 weeks. Changes in glucose homeostasis, energy metabolism and brown adipose tissue (BAT) function were assessed.

RESULTS

The STZ mice had elevated blood glucose and reduced plasma FGF21 levels, impaired glucose uptake in the BAT, and BAT mitochondria with absent or swollen cristae and fewer lipid vacuoles. LY2405319 significantly reduced blood glucose levels and this was associated with increased BAT glucose uptake and changes in gene expression and morphology, indicating improved mitochondrial lipid metabolism in the BAT. Importantly, the ability of LY2405319 to lower blood glucose in STZ mice was compromised after removing interscapular BAT.

CONCLUSIONS

Our results show that LY2405319 reduces blood glucose levels in insulin-deficient diabetes by improving BAT metabolism. Additional studies investigating the therapeutic potential of FGF21 for the treatment of type 1 diabetes are warranted.

An optimized protocol for human M2 macrophages using M-CSF and IL-4/IL-10/TGF-β yields a dominant immunosuppressive phenotype

Monocytes are highly abundant circulatory effector cells and play a vital role in driving or resolving inflammatory processes depending on their activation phenotype. We investigated and compared a panel of polarization protocols of blood-derived monocytes to achieve a stable, optimal and effective regimen for in vitro induction of immunosuppressive human macrophages, evaluating their surface receptor expression, cytokine profile, scavenging function and ability to suppress T-cell proliferation. Importantly, we assessed the effect of copolarization or secondary pro-inflammatory stimulation of a primary anti-inflammatory activation phenotype. A combination of IL-4/IL-10/TGF-β yielded a relatively stable and dominant immunosuppressive phenotype characterized by higher IL-10 production and down-regulated TNF-α, IL-6, CD86, CD274 and MHC II expression. Functionally, IL-4/IL-10/TGF-β-stimulated macrophages (M2) had a potent deactivating effect on a subsequent pro-inflammatory LPS/IFNγ-activated macrophage (M1) stimulation and significantly suppressed T-cell proliferation. Monocytes derived from patients with chronic inflammatory diseases could be induced to be anti-inflammatory using this protocol. Pre-differentiation with GM-CSF or M-CSF was further demonstrated to enhance final M1/M2 activation status. Our findings indicate a robust polarization protocol for generation of specific immunosuppressive human monocyte-derived macrophages.

Effects of resistance training on central blood pressure in obese young men

Central blood pressure is a predictor of the risk of cardiovascular disease (CVD), and the effects of resistance training (RT) on central blood pressure are largely unknown. This study explored the effects of high-intensity RT on central blood pressure, indices of arterial stiffness and wave reflection and inflammatory/atherogenic markers in overweight or obese, sedentary young men. Thirty-six participants were randomized to RT (12 weeks of training, 3/wk, n=28) or control groups (C, 12 weeks of no training, n=8) and assessed for changes in central and brachial blood pressures, augmentation index (AIx), carotid-femoral pulse wave velocity (cfPWV), carotid intima-media thickness (cIMT), body composition, lipids and inflammatory/atherogenic markers. High-intensity RT resulted in decreased central and brachial systolic/diastolic blood pressures (all P0.03), despite not altering AIx (P=0.34) or cfPWV (P=0.43). The vascular endothelial growth factor increased (P=0.03) after RT, without any change in cIMT, C-reactive protein, oxidized LDL (oxLDL) or other inflammatory markers (all P0.1). Changes in the central systolic blood pressure (cSBP) were positively correlated with changes in oxLDL (r=0.42, P=0.03) and soluble E-selectin (r=0.41, P=0.04). In overweight/obese young men, high-intensity RT decreases cSBP, independently of weight loss and changes in arterial stiffness. The cardioprotective effects of RT may be related to effects on central blood pressure.

Trajectories of loneliness during childhood and adolescence: predictors and health outcomes

The present study employed latent growth mixture modeling to discern distinct trajectories of loneliness using data collected at 2-year intervals from age 7-17 years (N = 586) and examine whether measures taken at age 5 years were good predictors of group membership. Four loneliness trajectory classes were identified: (1) low stable (37% of the sample), (2) moderate decliners (23%), (3) moderate increasers (18%), and (4) relatively high stable (22%). Predictors at age 5 years for the high stable trajectory were low trust beliefs, low trusting, low peer acceptance, parent reported negative reactivity, an internalizing attribution style, low self-worth, and passivity during observed play. The model also included outcome variables. We found that both the high stable and moderate increasing trajectories were associated with depressive symptoms, a higher frequency of visits to the doctor, and lower perceived general health at age 17. We discuss implications of findings for future empirical work.

Linking GABA(A) receptor subunits to alcohol-induced conditioned taste aversion and recovery from acute alcohol intoxication

GABA type A receptors (GABA(A)-R) are important for ethanol actions and it is of interest to link individual subunits with specific ethanol behaviors. We studied null mutant mice for six different GABA(A)-R subunits (α1, α2, α3, α4, α5 and δ). Only mice lacking the α2 subunit showed reduction of conditioned taste aversion (CTA) to ethanol. These results are in agreement with data from knock-in mice with mutation of the ethanol-sensitive site in the α2-subunit (Blednov et al., 2011). All together, they indicate that aversive property of ethanol is dependent on ethanol action on α2-containing GABA(A)-R. Deletion of the α2-subunit led to faster recovery whereas absence of the α3-subunit slowed recovery from ethanol-induced incoordination (rotarod). Deletion of the other four subunits did not affect this behavior. Similar changes in this behavior for the α2 and α3 null mutants were found for flurazepam motor incoordination. However, no differences in recovery were found in motor-incoordinating effects of an α1-selective modulator (zolpidem) or an α4-selective agonist (gaboxadol). Therefore, recovery of rotarod incoordination is under control of two GABA(A)-R subunits: α2 and α3. For motor activity, α3 null mice demonstrated higher activation by ethanol (1 g/kg) whereas both α2 (-/-) and α3 (-/Y) knockout mice were less sensitive to ethanol-induced reduction of motor activity (1.5 g/kg). These studies demonstrate that the effects of ethanol at GABAergic synapses containing α2 subunit are important for specific behavioral effects of ethanol which may be relevant to the genetic linkage of the α2 subunit with human alcoholism.

Behavioral actions of alcohol: phenotypic relations from multivariate analysis of mutant mouse data

Behavioral studies on genetically diverse mice have proven powerful for determining relationships between phenotypes and have been widely used in alcohol research. Most of these studies rely on naturally occurring genetic polymorphisms among inbred strains and selected lines. Another approach is to introduce variation by engineering single-gene mutations in mice. We have tested 37 different mutant mice and their wild-type controls for a variety (31) of behaviors and have mined this data set by K-means clustering and analysis of correlations. We found a correlation between a stress-related response (activity in a novel environment) and alcohol consumption and preference for saccharin. We confirmed several relationships detected in earlier genetic studies, including positive correlation of alcohol consumption with saccharin consumption and negative correlations with conditioned taste aversion and alcohol withdrawal severity. Introduction of single-gene mutations either eliminated or greatly diminished these correlations. The three tests of alcohol consumption used (continuous two-bottle choice and two limited access tests: drinking in the dark and sustained high alcohol consumption) share a relationship with saccharin consumption, but differ from each other in their correlation networks. We suggest that alcohol consumption is controlled by multiple physiological systems where single-gene mutations can disrupt the networks of such systems.

Identifying changes in the synaptic proteome of cirrhotic alcoholic superior frontal gyrus

Hepatic complications are a common side-effect of alcoholism. Without the detoxification capabilities of the liver, alcohol misuse induces changes in gene and protein expression throughout the body. A global proteomics approach was used to identify these protein changes in the brain. We utilised human autopsy tissue from the superior frontal gyrus (SFG) of six cirrhotic alcoholics, six alcoholics without comorbid disease, and six non-alcoholic non-cirrhotic controls. Synaptic proteins were isolated and used in two-dimensional differential in-gel electrophoresis coupled with mass spectrometry. Many expression differences were confined to one or other alcoholic sub-group. Cirrhotic alcoholics showed 99 differences in protein expression levels from controls, of which half also differed from non-comorbid alcoholics. This may reflect differences in disease severity between the sub-groups of alcoholics, or differences in patterns of harmful drinking. Alternatively, the protein profiles may result from differences between cirrhotic and non-comorbid alcoholics in subjects’ responses to alcohol misuse. Ten proteins were identified in at least two spots on the 2D gel; they were involved in basal energy metabolism, synaptic vesicle recycling, and chaperoning. These post-translationally modified isoforms were differentially regulated in cirrhotic alcoholics, indicating a level of epigenetic control not previously observed in this disorder.

Characterization of single-nucleotide variation in Indian-origin rhesus macaques (Macaca mulatta)

BACKGROUND

Rhesus macaques are the most widely utilized nonhuman primate model in biomedical research. Previous efforts have validated fewer than 900 single nucleotide polymorphisms (SNPs) in this species, which limits opportunities for genetic studies related to health and disease. Extensive information about SNPs and other genetic variation in rhesus macaques would facilitate valuable genetic analyses, as well as provide markers for genome-wide linkage analysis and the genetic management of captive breeding colonies.

RESULTS

We used the available rhesus macaque draft genome sequence, new sequence data from unrelated individuals and existing published sequence data to create a genome-wide SNP resource for Indian-origin rhesus monkeys. The original reference animal and two additional Indian-origin individuals were resequenced to low coverage using SOLiD™ sequencing. We then used three strategies to validate SNPs: comparison of potential SNPs found in the same individual using two different sequencing chemistries, and comparison of potential SNPs in different individuals identified with either the same or different sequencing chemistries. Our approach validated approximately 3 million SNPs distributed across the genome. Preliminary analysis of SNP annotations suggests that a substantial number of these macaque SNPs may have functional effects. More than 700 non-synonymous SNPs were scored by Polyphen-2 as either possibly or probably damaging to protein function and these variants now constitute potential models for studying functional genetic variation relevant to human physiology and disease.

CONCLUSIONS

Resequencing of a small number of animals identified greater than 3 million SNPs. This provides a significant new information resource for rhesus macaques, an important research animal. The data also suggests that overall genetic variation is high in this species. We identified many potentially damaging non-synonymous coding SNPs, providing new opportunities to identify rhesus models for human disease.

Testing the silence of mutations: Transcriptomic and behavioral studies of GABA(A) receptor α1 and α2 subunit knock-in mice

Knock-in mice were constructed with mutations in the α1 (H(270), A(277)) and α2 (H(270), A(277)) subunits of the GABAA receptor, which resulted in receptors that lacked modulation by ethanol but retained normal responses to GABA in vitro. A key question is whether these mutant receptors also function normally in vivo. Perturbation of brain function was evaluated by gene expression profiling in the cerebral cortex and by behavioral pharmacology experiments with GABAergic drugs. Analysis of individual transcripts found only six transcripts that were changed in α1 knock-in mice and three in the α2 mutants (p<0.05, corrected for multiple comparisons). Two transcripts that are sensitive to neuronal activity, Arc and Fos, increased about 250% in the α2 mutants, and about 50% in the α1 mutants. Behavioral effects (loss of righting reflex, rotarod) of flurazepam and pentobarbital were not different between α2 mutants and wild-type, but they were enhanced for α1 knock-in mice. These results indicate that introduction of these mutations in the α2 subunit of the GABAA receptor does not produce marked perturbation of brain function, as measured by gene expression and GABAergic behavioral responses, but the same mutations in the α1 subunit produce more pronounced changes, especially in GABAergic function.

Loss of ethanol conditioned taste aversion and motor stimulation in knockin mice with ethanol-insensitive α2-containing GABA(A) receptors

GABA type A receptors (GABA(A)-Rs) are potential targets of ethanol. However, there are multiple subtypes of this receptor, and, thus far, individual subunits have not been definitively linked with specific ethanol behavioral actions. Interestingly, though, a chromosomal cluster of four GABA(A)-R subunit genes, including α2 (Gabra2), was associated with human alcoholism (Am J Hum Genet 74:705-714, 2004; Pharmacol Biochem Behav 90:95-104, 2008; J Psychiatr Res 42:184-191, 2008). The goal of our study was to determine the role of receptors containing this subunit in alcohol action. We designed an α2 subunit with serine 270 to histidine and leucine 277 to alanine mutations that was insensitive to potentiation by ethanol yet retained normal GABA sensitivity in a recombinant expression system. Knockin mice containing this mutant subunit were tested in a range of ethanol behavioral tests. These mutant mice did not develop the typical conditioned taste aversion in response to ethanol and showed complete loss of the motor stimulant effects of ethanol. Conversely, they also demonstrated changes in ethanol intake and preference in multiple tests. The knockin mice showed increased ethanol-induced hypnosis but no difference in anxiolytic effects or recovery from acute ethanol-induced motor incoordination. Overall, these studies demonstrate that the effects of ethanol at GABAergic synapses containing the α2 subunit are important for specific behavioral effects of ethanol that may be relevant to the genetic linkage of this subunit with human alcoholism.

Inhaled anesthetic responses of recombinant receptors and knockin mice harboring α2(S270H/L277A) GABA(A) receptor subunits that are resistant to isoflurane

The mechanism by which the inhaled anesthetic isoflurane produces amnesia and immobility is not understood. Isoflurane modulates GABA(A) receptors (GABA(A)-Rs) in a manner that makes them plausible targets. We asked whether GABA(A)-R α2 subunits contribute to a site of anesthetic action in vivo. Previous studies demonstrated that Ser270 in the second transmembrane domain is involved in the modulation of GABA(A)-Rs by volatile anesthetics and alcohol, either as a binding site or a critical allosteric residue. We engineered GABA(A)-Rs with two mutations in the α2 subunit, changing Ser270 to His and Leu277 to Ala. Recombinant receptors with these mutations demonstrated normal affinity for GABA, but substantially reduced responses to isoflurane. We then produced mutant (knockin) mice in which this mutated subunit replaced the wild-type α2 subunit. The adult mutant mice were overtly normal, although there was evidence of enhanced neonatal mortality and fear conditioning. Electrophysiological recordings from dentate granule neurons in brain slices confirmed the decreased actions of isoflurane on mutant receptors contributing to inhibitory synaptic currents. The loss of righting reflex EC(50) for isoflurane did not differ between genotypes, but time to regain the righting reflex was increased in N(2) generation knockins. This effect was not observed at the N(4) generation. Isoflurane produced immobility (as measured by tail clamp) and amnesia (as measured by fear conditioning) in both wild-type and mutant mice, and potencies (EC(50)) did not differ between the strains for these actions of isoflurane. Thus, immobility or amnesia does not require isoflurane potentiation of the α2 subunit.

Altered natural killer (NK) cell frequency and phenotype in latent autoimmune diabetes in adults (LADA) prior to insulin deficiency

Approximately 10% of the patients diagnosed with type 2 diabetes (T2D) have detectable serum levels of glutamic acid decarboxylase 65 autoantibodies (GADA). These patients usually progress to insulin dependency within a few years, and are classified as being latent autoimmune diabetes in adults (LADA). A decrease in the frequency of peripheral blood natural killer (NK) cells has been reported recently in recent-onset T1D and in high-risk individuals prior to the clinical onset. As NK cells in LADA patients have been investigated scarcely, the aim of this study was to use multicolour flow cytometry to define possible deficiencies or abnormalities in the frequency or activation state of NK cells in LADA patients prior to insulin dependency. All patients were GADA-positive and metabolically compensated, but none were insulin-dependent at the time blood samples were taken. LADA patients exhibited a significant decrease in NK cell frequency in peripheral blood compared to healthy individuals (P=0.0018), as reported previously for recent-onset T1D patients. Interestingly, NKG2D expression was increased significantly (P<0.0001), whereas killer cell immunoglobulin-like receptor (KIR)3DL1 expression was decreased (P<0.0001) within the NK cell population. These observations highlight a defect in both frequency and activation status of NK cells in LADA patients and suggest that this immunological alteration may contribute to the development of autoimmune diabetes by affecting peripheral tolerance. Indeed, recent evidence has demonstrated a regulatory function for NK cells in autoimmunity. Moreover, the decrease in NK cell number concords with observations obtained in recent-onset T1D, implying that similar immunological dysfunctions may contribute to the progression of both LADA and T1D.

Behavioral differences between C57BL/6J x FVB/NJ and C57BL/6J x NZB/B1NJ F1 hybrid mice: relation to control of ethanol intake

C57BL/6J x FVB/NJ F1 (B6 x FVB) mice consume more alcohol than C57BL/6J x NZB/B1NJ F1 (B6 x NZB) mice and this high alcohol consumption is stable after abstinence whereas B6 x NZB show reduced consumption, thus providing models of Sustained Alcohol Preference (SAP) and Reduced Alcohol Preference (RAP). In female hybrids, we assessed several behavioral responses to define behaviors which might predict SAP and RAP. B6 x FVB exhibited less severe ethanol-induced conditioned taste aversion and were less sensitive to ethanol-induced loss of righting reflex than B6 x NZB. Both hybrids demonstrated ethanol-induced place preference and a low ethanol withdrawal severity. We found that these hybrids differ in their sensitivity to the aversive and sedative, but not rewarding, effects of ethanol. Results of elevated plus maze, mirror chamber, and locomotor tests reveal B6 x FVB mice are less anxious and more active than B6 x NZB mice. Results obtained offer insights about factors that determine SAP and RAP in these new genetic models of alcohol consumption.

In vitro biocompatibility of hydroxyapatite-reinforced polymeric composites manufactured by selective laser sintering

The selective laser sintering (SLS) technique was used to manufacture hydroxyapatite-reinforced polyethylene and polyamide composites as potential customized maxillofacial implants. In vitro tests were carried out to assess cellular responses, in terms of cell attachment, morphology, proliferation, differentiation, and mineralized nodule formation, using primary human osteoblast cells. This study showed that the SLS composite processed was biocompatible, with no adverse effects observed on cell viability and metabolic activity, supporting a normal metabolism and growth pattern for osteoblasts. Positive von Kossa staining demonstrated the presence of bone-like mineral on the SLS materials. Higher hydroxyapatite content composites enhanced cell proliferation, increased alkaline phosphatase activity, and produced more osteocalcin. The present findings showed that SLS materials have good in vitro biocompatibility and hence demonstrated biologically the potential of SLS for medical applications.

Bidirectional modulation of isoflurane potency by intrathecal tetrodotoxin and veratridine in rats

BACKGROUND AND PURPOSE

Results from several studies point to voltage-gated Na(+) channels as potential mediators of the immobility produced by inhaled anaesthetics. We hypothesized that the intrathecal administration of tetrodotoxin, a drug that blocks Na(+) channels, should enhance anaesthetic potency, and that concurrent administration of veratridine, a drug that augments Na(+) channel opening, should reverse the increase in potency.

EXPERIMENTAL APPROACH

We measured the change in isoflurane potency for reducing movement in response to a painful stimulus as defined by MAC (minimum alveolar concentration of anaesthetic required to abolish movement in 50% of subjects) caused by intrathecal infusion of various concentrations of tetrodotoxin into the lumbothoracic subarachnoid space of rats, and the change in MAC caused by the administration of a fixed dose of tetrodotoxin plus various doses of intrathecal veratridine.

KEY RESULTS

Intrathecal infusion of tetrodotoxin (0.078-0.63 microM) produced a reversible dose-related decrease in MAC, of more than 50% at the highest concentration. Intrathecal co-administration of veratridine (1.6-6.4 microM) reversed this decrease in a dose-related manner, with nearly complete reversal at the highest veratridine dose tested.

CONCLUSIONS AND IMPLICATIONS

Intrathecal administration of tetrodotoxin increases isoflurane potency (decreases isoflurane MAC), and intrathecal administration of veratridine counteracts this effect in vivo. These findings are consistent with a role for voltage-gated Na(+) channel blockade in the immobility produced by inhaled anaesthetics.

Characterization, quantification, and replication of human sinus bone for surgery simulation phantoms

The requirement for artificial but realistic, tactile, anatomical models for surgical practice in medical simulation is increasingly evident and shows potential for greater efficiency and availability, and lower costs. Anatomically correct, detailed models with the physical surgical characteristics of real tissue, combined with the ability to reproduce one-off cases, would provide an invaluable tool in the development of surgery. This research work investigates the capture of geometrical and physical data from the human sinus to subsequently direct the production and optimization of such simulation phantoms. Micro-computed tomography analysis of the entire sinus was performed to characterize the sinus complex geometry. Following an extensive review, specialized mechanical testing apparatus and methods relevant to the surgical methods employed were designed and produced. This provided comparative analysis methods for both biological and artificial phantom materials and allowed the optimization of phantom materials with respect to the derived target values.

Popliteal vein compression syndrome: obesity, venous disease and the popliteal connection

Objectives

Obesity and venous disease are commonly encountered together. The aetio- logical relationship, however, has not been clear. Popliteal venous compression (PVC) has been encountered both on ultrasound and venographically. In this study, patients with symptoms and/or signs of chronic venous hypertension with PVC were investigated and the relationship to obesity was defined.

Methods

A total of 89 patients were included in the study, of which 49 limbs were classified as having PVC defined as a greater than 90% reduction in the maximum internal diameter (ID) of the popliteal vein (POPV) with knee locking. Forty consecutive limbs with venous disease with no evidence of PVC were used as controls. The body mass index (BMI) of each group was calculated and the clinical symptoms and signs were documented. After the failure of conservative treatment, 30 of the 49 underwent open popliteal decompression.

Results

Patients with PVC were found to have a BMI of 34.6 ± 6.2 compared with 25.3 ± 3.0 of the controls. The POPV ID in the PVC group before and after knee locking changed from 11.7 ± 5.0 to 1.0 ± 2.1 mm, respectively. Postoperatively, the POPV ID before and after knee locking changed from 10.2 ± 2.2 to 9.0 ± 1.5 mm, respectively. At 16.2 ± 12.1 months follow-up, all the major clinical parameters improved at a statistically significant level.

Conclusions

There appears to be a relationship between obesity, chronic venous disease and PVC. POPV compression syndrome may clarify the previously unexplained venous presentations. Surgical decompression provides good results in patients unresponsive to conservative treatment.

Deletion of vanilloid receptor (TRPV1) in mice alters behavioral effects of ethanol

The vanilloid receptor TRPV1 is activated by ethanol and this may be important for some of the central and peripheral actions of ethanol. To determine if this receptor has a role in ethanol-mediated behaviors, we studied null mutant mice in which the Trpv1 gene was deleted. Mice lacking this gene showed significantly higher preference for ethanol and consumed more ethanol in a two-bottle choice test as compared with wild type littermates. Null mutant mice showed shorter duration of loss of righting reflex induced by low doses of ethanol (3.2 and 3.4 g/kg) and faster recovery from motor incoordination induced by ethanol (2 g/kg). However, there were no differences between null mutant and wild type mice in severity of ethanol-induced acute withdrawal (4 g/kg) or conditioned taste aversion to ethanol (2.5 g/kg). Two behavioral phenotypes (decreased sensitivity to ethanol-induced sedation and faster recovery from ethanol-induced motor incoordination) seen in null mutant mice were reproduced in wild type mice by injection of a TRPV1 antagonist, capsazepine (10 mg/kg). These two ethanol behaviors were changed in the opposite direction after injection of capsaicin, a selective TRPV1 agonist, in wild type mice. The studies provide the first evidence that TRPV1 is important for specific behavioral actions of ethanol.

Advanced computer-aided design for bone tissue-engineering scaffolds

The design of scaffolds with an intricate and controlled internal structure represents a challenge for tissue engineering. Several scaffold-manufacturing techniques allow the creation of complex architectures but with little or no control over the main features of the channel network such as the size, shape, and interconnectivity of each individual channel, resulting in intricate but random structures. The combined use of computer-aided design (CAD) systems and layer-manufacturing techniques allows a high degree of control over these parameters with few limitations in terms of achievable complexity. However, the design of complex and intricate networks of channels required in CAD is extremely time-consuming since manually modelling hundreds of different geometrical elements, all with different parameters, may require several days to design individual scaffold structures. An automated design methodology is proposed by this research to overcome these limitations. This approach involves the investigation of novel software algorithms, which are able to interact with a conventional CAD program and permit the automated design of several geometrical elements, each with a different size and shape. In this work, the variability of the parameters required to define each geometry has been set as random, but any other distribution could have been adopted. This methodology has been used to design five cubic scaffolds with interconnected pore channels that range from 200 to 800 μm in diameter, each with an increased complexity of the internal geometrical arrangement. A clinical case study, consisting of an integration of one of these geometries with a craniofacial implant, is then presented.

Polymorphic microsatellite loci for the common marmoset (Callithrix jacchus) designed using a cost- and time-efficient method

We describe a cost- and time-efficient method for designing new microsatellite markers in any species with substantial genomic DNA sequence data available. Using this technique, we report 14 new polymorphic dinucleotide microsatellite loci isolated from the common marmoset. The relative yield of new polymorphisms was higher with less labor than described in previous marmoset studies. Of 20 loci initially evaluated, 14 were polymorphic and amplified reliably (70% success rate). The number of alleles ranged from 3 to 9 with heterozygosity varying from 0.48 to 0.83.

Genetic factors influencing alcohol dependence

Plentiful data from both animal and human studies support the importance of genetic influences in substance abuse and dependence (Bierut et al., 1998; Tsuang et al., 1998; Kendler et al., 2003). This review summarizes the evidence supporting such genetic influences, places them into perspective regarding animal and human studies, discusses the importance of both genes and environment, and highlights some specific genes of interest regarding the vulnerabilities for problems associated with alcohol use disorders. A long history of repetitive heavy use of alcohol exists across generations as well as the high prevalence of alcohol-related problems in Western societies. Moreover, the information offered here addresses the importance of more general issues regarding genetics and gene expression related to alcohol abuse and dependence.

Fabrication of porous bioactive structures using the selective laser sintering technique

Hydroxyapatite, a ceramic with which natural bone inherently bonds, has been incorporated into a polymer matrix to enhance the bioactivity of implant materials. In order to manufacture custom-made bioactive implants rapidly, selective laser sintering has been investigated to fabricate hydroxyapatite and polyamide composites and their properties investigated. One objective of this research was to identify the maximum hydroxyapatite content that could be incorporated into the matrix, which was sintered at various parameters. The study focused on investigating the control of porosity and pore size of the matrix by manipulating the selective laser sintering parameters of the laser power and laser scan speed. The interception method was used to analyse the internal porous morphology of the matrices which were cross-sectioned through the vertical plane. Most notably, all structures built demonstrated interconnection and penetration throughout the matrix. Liquid displacement was also used to analyse the porosity of the matrices. The laser power showed a negative relationship between porosity and variation in parameter values until a critical power value was reached. However, the same relationship for laser scan speed matrices was inconsistent. The effects of the laser power and laser scanning speed on the features of porous structures that could influence cell spreading, proliferation, and bone regeneration are presented.

Novel landmark-guided routes in ants

We review studies in which ants familiar with fixed routes between their nest and a feeding site are displaced from one of these destinations to an unfamiliar site away from the route. Ants can reach their goal from such novel release sites guided by distant landmarks. We suggest that an ant's ability to take such novel landmark-guided routes after displacement is a by-product of the robustness of normal route-following and is unlikely to reflect the ant's use of a map-like knowledge of its surroundings.

Human-specific changes of genome structure detected by genomic triangulation

Knowledge of the rhesus macaque genome sequence enables reconstruction of the ancestral state of the human genome before the divergence of chimpanzees. However, the draft quality of nonhuman primate genome assemblies challenges the ability of current methods to detect insertions, deletions, and copy-number variations between humans, chimpanzees, and rhesus macaques and hinders the identification of evolutionary changes between these species. Because of the abundance of segmental duplications, genome comparisons require the integration of genomic assemblies and data from large-insert clones, linkage maps, and radiation hybrid maps. With genomic triangulation, an integrative method that reconstructs ancestral states and the structural evolution of genomes, we identified 130 human-specific breakpoints in genome structure due to rearrangements at an intermediate scale (10 kilobases to 4 megabases), including 64 insertions affecting 58 genes. Comparison with a human structural polymorphism database indicates that many of the rearrangements are polymorphic.

Defining the dopamine transporter proteome by convergent biochemical and in silico analyses

Monoamine transporters play a key role in neuronal signaling by mediating reuptake of neurotransmitters from the synapse. The function of the dopamine transporter (DAT), an important member of this family of transporters, is regulated by multiple signaling mechanisms, which result in altered cell surface trafficking of DAT. Protein-protein interactions are likely critical for this mode of transporter regulation. In this study, we identified proteins associated with DAT by immunoprecipitation (IP) followed by mass spectrometry. We identified 20 proteins with diverse cellular functions that can be classified as trafficking proteins, cytoskeletal proteins, ion channels and extracellular matrix-associated proteins. DAT was found to associate with the voltage-gated potassium channel Kv2.1 and synapsin Ib, a protein involved in regulating neurotransmitter release. An in silico analysis provided evidence for common transcriptional regulation of the DAT proteome genes. In summary, this study identified a network of proteins that are primary candidates for functional regulation of the DAT, an important player in mechanisms of mental disorders and drug addiction.

Comparison of electrically and mechanically induced soleus H-reflex depression

OBJECTIVES

The aim of the present investigation was to compare the responses of mechanically-evoked and electrically-evoked conditioning among three different stimulus intensities and provide possible insight in determining whether these two types of inhibitory conditioning demonstrate the same response across the motor pool.

METHODS

The soleus H-reflex was tested under three different stimulus intensities (25% Hmax, 50% Hmax, and Hmax), and peak to peak amplitudes were recorded after either mechanical or electrical conditioning. For electrical conditioning, the ankle was held at 90 degrees, whereas mechanical conditioning utilized a 10 degree passive dorsiflexion at 15 degrees/sec back to the 90 degree position. All H-reflex measurements were recorded with the ankle at 90 degrees.

RESULTS

A 3 x 2 (stimulus intensity x treatment condition) repeated measures ANOVA indicated significant main effects for stimulus intensity (FGG = 16.23; p = .003) and condition (FGG = 28.48; p < .001), as well as an interaction (F(2,18) = 6.59; p = .008). Simple main effects identified significantly more H-reflex depression for mechanical conditioning (94%, 91%, and 44%) compared to electrical conditioning (65%, 55%, and 19%) at 25% Hmax, 50% Hmax, and Hmax, respectively.

CONCLUSIONS

There appears to be more mechanically than electrically stimulated H-reflex depression when testing at 25% Hmax, 50% Hmax, and Hmax. These results demonstrate the influence of Ia discharge properties on H-reflex depression and may suggest differences in the affinity of Ia terminals to intrinsic presynaptic inhibition at different stimulus intensities.

Selective laser sintering of hydroxyapatite reinforced polyethylene composites for bioactive implants and tissue scaffold development

Selective laser sintering (SLS) has been investigated for the production of bioactive implants and tissue scaffolds using composites of high-density polyethylene (HDPE) reinforced with hydroxyapatite (HA) with the aim of achieving the rapid manufacturing of customized implants. Single-layer and multilayer block specimens made of HA-HDPE composites with 30 and 40 vol % HA were sintered successfully using a CO2 laser sintering system. Laser power and scanning speed had a significant effect on the sintering behaviour. The degree of particle fusion and porosity were influenced by the laser processing parameters, hence control can be attained by varying these parameters. Moreover, the SLS processing allowed exposure of HA particles on the surface of the composites and thereby should provide bioactive products. Pores existed in the SLS-fabricated composite parts and at certain processing parameters a significant fraction of the pores were within the optimal sizes for tissue regeneration. The results indicate that the SLS technique has the potential not only to fabricate HA-HDPE composite products but also to produce appropriate features for their application as bioactive implants and tissue scaffolds.

An isoflurane- and alcohol-insensitive mutant GABA(A) receptor alpha(1) subunit with near-normal apparent affinity for GABA: characterization in heterologous systems and production of knockin mice

Volatile anesthetics and alcohols enhance transmission mediated by gamma-aminobutyric acid type A receptors (GABA(A)Rs) in the central nervous system, an effect that may underlie some of the behavioral actions of these agents. Substituting a critical serine residue within the GABA(A)R alpha(1) subunit at position 270 with the larger residue histidine eliminated receptor modulation by isoflurane, but it also affected receptor gating (increased GABA sensitivity). To correct the shift in GABA sensitivity of this mutant, we mutated a second residue, leucine at position 277 to alanine. The double mutant alpha(1)(S270H,L277A)beta(2)gamma(2S) GABA(A)R was expressed in Xenopus laevis oocytes and human embryonic kidney (HEK)293 cells, and it had near-normal GABA sensitivity. However, rapid application of a brief GABA pulse to receptors expressed in HEK293 cells revealed that the deactivation was faster in double mutant than in wild-type receptors. In all heterologous systems, the enhancing effect of isoflurane and ethanol was greatly decreased in the double mutant receptor. Homozygous knockin mice harboring the double mutation were viable and presented no overt abnormality, except hyperactivity. This knockin mouse line should be useful in determining which behavioral actions of volatile anesthetics and ethanol are mediated by the GABA(A)Rs containing the alpha(1) subunit.

Layer Manufacturing for in Vivo Devices

Traditional in vivo devices fabricated to be used as implantation devices included sutures, plates, pins, screws, and joint replacement implants. Also, akin to developments in regenerative medicine and drug delivery, there has been the pursuit of less conventional in vivo devices that demand complex architecture and composition, such as tissue scaffolds. Commercial means of fabricating traditional devices include machining and moulding processes. Such manufacturing techniques impose considerable lead times and geometrical limitations, and restrict the economic production of customized products. Attempts at the production of non-conventional devices have included particulate leaching, solvent casting, and phase transition. These techniques cannot provide the desired total control over internal architecture and compositional variation, which subsequently restricts the application of these products. Consequently, several parties are investigating the use of freeform layer manufacturing techniques to overcome these difficulties and provide viable in vivo devices of greater functionality. This paper identifies the concepts of rapid manufacturing (RM) and the development of biomanufacturing based on layer manufacturing techniques. Particular emphasis is placed on the development and experimentation of new materials for bio-RM, production techniques based on the layer manufacturing concept, and computer modelling of in vivo devices for RM techniques.

A note on chirality in NMR spectroscopy

Using simple symmetry arguments we give proofs of the derivations of the manifestation of chirality in the chemical shift and spin-spin coupling constant in nuclear magnetic resonance and relate our proofs to earlier discussions.

Male transgenic glycine receptor alpha1 (S267Q) mutant mice display a hyperekplexia-like increase in acoustic startle responses

Glycine receptors (GlyR) are ligand-gated ion channels that inhibit neurotransmission in the spinal cord and brainstem, and mutations in GlyR can cause the human disease hyperekplexia, which is characterized by elevated startle responses. Recently, the GlyR alpha1S267Q mutation was shown to disrupt normal GlyR function, and knock-in mice harboring this mutation displayed profoundly increased acoustic startle responses and reduced glycine-stimulated the chloride flux [Findlay, G.S., Phelan, R., Roberts, M.T., Homanics, G.E., Bergeson, S.E., Lopreato, G.F., Mihic, S.J., Blednov, Y.A., Harris, R.A. 2003. Glycine receptor knock-in mice and hyperekplexia: comparisons with the null mutant. J Neurosci 23, 8051-8059.]. In this study, a transgenic mouse model expressing this S267Q mutation was evaluated using similar techniques to determine if these mice are similarly affected. Male transgenic mice displayed increased acoustic startle responses. However, decreases in glycine-stimulated strychnine-sensitive radioactive chloride (36Cl-) uptake were not observed in spinal cord and brainstem synaptoneurosomes from transgenic mice. No changes in habituation or prepulse inhibition of startle responses or spontaneous locomotion in response to taurine were observed as a result of presence of the transgene. Consistent with previous studies using immunoblotting and strychnine binding [Findlay, G.S., Wick, M.J., Mascia, M.P., Wallace, D., Miller, G.W., Harris, R.A., Blednov, Y.A. 2002. Transgenic expression of a mutant glycine receptor decreases alcohol sensitivity of mice. J Pharmacol Exp Ther 300, 526-534.], the glycine-stimulated strychnine-sensitive chloride flux of cortical microsacs in transgenic mice confirmed the ectopic expression of transgenic GlyR. These results support both the idea that transgenic expression of the S267Q mutation produces a less dramatic phenotype as compared to the knock-in mouse model as well as the idea that the in vivo acoustic startle test (as compared to the in vitro chloride flux assay) is particularly sensitive to disruptions in GlyR function.

Implications for prediction and hazard assessment from the 2004 Parkfield earthquake

Obtaining high-quality measurements close to a large earthquake is not easy: one has to be in the right place at the right time with the right instruments. Such a convergence happened, for the first time, when the 28 September 2004 Parkfield, California, earthquake occurred on the San Andreas fault in the middle of a dense network of instruments designed to record it. The resulting data reveal aspects of the earthquake process never before seen. Here we show what these data, when combined with data from earlier Parkfield earthquakes, tell us about earthquake physics and earthquake prediction. The 2004 Parkfield earthquake, with its lack of obvious precursors, demonstrates that reliable short-term earthquake prediction still is not achievable. To reduce the societal impact of earthquakes now, we should focus on developing the next generation of models that can provide better predictions of the strength and location of damaging ground shaking.