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.