A meta-analysis of Hodgkin lymphoma reveals 19p13.3 TCF3 as a novel susceptibility locus.

Recent genome-wide association studies (GWAS) of Hodgkin lymphoma (HL) have identified associations with genetic variation at both HLA and non-HLA loci; however, much of heritable HL susceptibility remains unexplained. Here we perform a meta-analysis of three HL GWAS totaling 1,816 cases and 7,877 controls followed by replication in an independent set of 1,281 cases and 3,218 controls to find novel risk loci. We identify a novel variant at 19p13.3 associated with HL (rs1860661; odds ratio (OR)=0.81, 95% confidence interval (95% CI) = 0.76-0.86, P(combined) = 3.5 × 10(-10)), located in intron 2 of TCF3 (also known as E2A), a regulator of B- and T-cell lineage commitment known to be involved in HL pathogenesis. This meta-analysis also notes associations between previously published loci at 2p16, 5q31, 6p31, 8q24 and 10p14 and HL subtypes. We conclude that our data suggest a link between the 19p13.3 locus, including TCF3, and HL risk.

Genetic variants in the region of the C1q genes are associated with rheumatoid arthritis.

Rodent models for arthritis implicate a role for complement in disease development and progression. In humans, complement deposition has been observed in inflamed synovia of rheumatoid arthritis (RA) patients. In this study we analysed whether genetic variants of complement component C1q predispose to RA. We genotyped single nucleotide polymorphisms (SNPs) in and around the C1q genes, C1qA, C1qB and C1qC, in a Dutch set of 845 RA cases and 1046 controls. Replication was sought in a sample set from North America (868 cases/1193 controls), and a meta-analysis was performed in a combined samples set of 8000 cases and 23 262 controls of European descent. We determined C1q serum levels in relation to C1q genotypes. In the discovery phase, five of the 13 SNPs tested in the C1q genes showed a significant association with RA. Additional analysis of the genomic area around the C1q genes revealed that the strongest associating SNPs were confined to the C1q locus. Within the C1q locus we observed no additional signal independent of the strongest associating SNP, rs292001 [odds ratio (OR) = 0·72 (0·58-0·88), P = 0·0006]. The variants of this SNP were associated with different C1q serum levels in healthy controls (P = 0·006). Interestingly, this SNP was also associated significantly in genome-wide association studies (GWAS) from the North American Rheumatoid Arthritis Consortium study, confirming the association with RA [OR = 0·83 (0·69-1·00), P = 0·043]. Combined analysis, including integrated data from six GWAS studies, provides support for the genetic association. Genetic variants in C1q are correlated with C1q levels and may be a risk for the development of RA.

A genetic variant in granzyme B is associated with progression of joint destruction in rheumatoid arthritis.

OBJECTIVE: Genetic factors account for an estimated 45-58% of the variance in joint destruction in rheumatoid arthritis (RA). The serine proteinase granzyme B induces target cell apoptosis, and several in vitro studies suggest that granzyme B is involved in apoptosis of chondrocytes. Serum levels of granzyme B are increased in RA and are also associated with radiographic erosions. The aim of this study was to investigate GZMB as a candidate gene accounting for the severity of joint destruction in RA. METHODS: A total of 1,418 patients with 4,885 radiograph sets of the hands and feet from 4 independent cohorts were studied. First, explorative analyses were performed in 600 RA patients in the Leiden Early Arthritis Clinic cohort. Fifteen single-nucleotide polymorphisms (SNPs) tagging GZMB were tested. Significantly associated SNPs were genotyped in data sets representing patients from the Groningen, Sheffield, and Lund cohorts. In each data set, the relative increase in the annual rate of progression in the presence of a genotype was assessed. Data were summarized in a meta-analysis. The association of GZMB with the RNA expression level of the GZMB genomic region was tested by mapping expression quantitative trait loci (QTLs) on 1,469 whole blood samples. RESULTS: SNP rs8192916 was significantly associated with the rate of joint destruction in the first cohort and in the meta-analysis of all data sets. Patients homozygous for the minor allele of rs8192916 had a higher rate of joint destruction per year compared with other patients (P = 7.8 × 10(-4)). Expression QTL of GZMB identified higher expression in the presence of the minor allele of rs8192916 (P = 2.27 × 10(-5)). CONCLUSION: SNP rs8192916 located in GZMB is associated with the progression of joint destruction in RA as well as with RNA expression in whole blood.

Modal interactions of flexural and torsional vibrations in a microcantilever.

The nonlinear interactions between flexural and torsional modes of a microcantilever are experimentally studied. The coupling is demonstrated by measuring the frequency response of one mode, which is sensitive to the motion of another resonance mode. The flexural-flexural, torsional-torsional and flexural-torsional modes are coupled due to nonlinearities, which affect the dynamics at high vibration amplitudes and cause the resonance frequency of one mode to depend on the amplitude of the other modes. We also investigate the nonlinear dynamics of torsional modes, which cause a frequency stiffening of the response. By simultaneously driving another torsional mode in the nonlinear regime, the nonlinear response is tuned from stiffening to weakening. By balancing the positive and negative cubic nonlinearities a linear response is obtained for the strongly driven system. The nonlinear modal interactions play an important role in the dynamics of multi-mode scanning probe microscopes.

Exome sequencing in a family segregating for celiac disease.

Celiac disease is a multifactorial disorder caused by an unknown number of genetic factors interacting with an environmental factor. Hence, most patients are singletons and large families segregating with celiac disease are rare. We report on a three-generation family with six patients in which the inheritance pattern is consistent with an autosomal dominant model. To date, 27 loci explain up to 40% of the heritable disease risk. We hypothesized that part of the missing heritability is because of low frequency or rare variants. Such causal variants could be more prominent in multigeneration families where private mutations might co-segregate with the disease. They can be identified by linkage analysis combined with whole exome sequencing. We found three linkage regions on 4q32.3-4q33, 8q24.13-8q24.21 and 10q23.1-10q23.32 that segregate with celiac disease in this family. We performed exome sequencing on two affected individuals to investigate the positional candidate regions and the remaining exome for causal nonsense variants. We identified 12 nonsense mutations with a low frequency (minor allele frequency <10%) present in both individuals, but none mapped to the linkage regions. Two variants in the CSAG1 and KRT37 genes were present in all six affected individuals. Two nonsense variants in the MADD and GBGT1 genes were also present in 5 of 6 and 4 of 6 individuals, respectively; future studies should determine if any of these nonsense variants is causally related to celiac disease.

Celiac disease: moving from genetic associations to causal variants.

Genome-wide association studies are providing insight into the genetic basis of common complex diseases: more than 1150 genetic loci [2165 unique single nucleotide polymorphisms (SNPs)] have recently been associated to 159 complex diseases. The hunt for genes contributing to immune-related diseases has been particularly successful in celiac disease, for example, with 27 genome-wide significantly associated loci identified so far. One of the current challenges is how to move from a genetic association with a disease to finding disease-associated genes and causal variants, as a step towards understanding the underlying disease process. About 50% of disease-associated SNPs affect the expression of nearby genes (so-called expression quantitative traits loci or eQTLs) and these can provide clues for finding causal variants. Although eQTLs can be useful, fine mapping and sequencing are required to refine the association signal. Ultimately, sophisticated study designs will be needed to find the causal variants involved in complex diseases. In this review, we use celiac disease as an example to describe the different aspects that need to be considered on the path from genetic association to disease-causing variants.

Nonlinear modal interactions in clamped-clamped mechanical resonators.

A theoretical and experimental investigation is presented on the intermodal coupling between the flexural vibration modes of a single clamped-clamped beam. Nonlinear coupling allows an arbitrary flexural mode to be used as a self-detector for the amplitude of another mode, presenting a method to measure the energy stored in a specific resonance mode. The observed complex nonlinear dynamics are quantitatively captured by a model based on coupling of the modes via the beam extension; the same mechanism is responsible for the well-known Duffing nonlinearity in clamped-clamped beams.

The effect of temperature and pH on the co-operative behavior of Mg2+ -stimulated acto-myosin-ATPase and the inhibition by IMP.

We have previously reported our finding that IMP inhibits the Mg2+ -stimulated acto-myosin-ATPase activity of isolated actin and myosin. These experiments were undertaken at 35 degrees C and pH 7.0. It was also shown that the binding of actin to myosin was cooperative and that in the presence of IMP the Hill coefficient was decreased. The experiments shown here were carried out with isolated actin and myosin at three temperatures (25 degrees C, 31 degrees C and 37 degrees C) and three pH values (6, 7 and 8). The results show that: (i) the Mg2+ -stimulated acto-myosin-ATPase activity decreases with decreasing temperature; (ii) the Mg2+ -stimulated acto-myosin-ATPase activity is lower at pH = 6 and 8 compared to pH = 7; (iii) the effect of temperature and pH on the Mg2+ -stimulated acto-myosin-ATPase activity can be explained by a decrease in co-operativity between actin and myosin; (iv) IMP inhibits the Mg2+ -stimulated acto-myosin-ATPase activity at all temperatures and pH values. The greatest inhibition is found at pH = 7; and (v) the inhibition by pH + IMP is about the same for pH = 6 and pH = 7; at pH = 8 this combined inhibition is slightly higher. This leads to the same decrease in Mg2+ -stimulated acto-myosin-ATPase activity. Muscle fatigue can be explained by a combination of non-regulatory factors (for example pH) and regulatory factors (such as IMP) and from our results we conclude that IMP serves as an additional regulatory safety switch to maintain the balance between energy consumption and energy production and thereby preventing an energy crisis during exhaustive exercise of short duration.

Benzodiazepine side-effects: from the bench to the clinic.

This article introduces a special issue of Current Pharmaceutical Design focusing on the various side effects of benzodiazepine medications. We argue that an increased awareness of the risk of dependence, withdrawal symptoms upon discontinuation, and cognitive side effects of the benzodiazepines has likely contributed to the decline in their prescription rate over the last two decades, as has increased availability of alternative pharmacologic and non-pharmacologic treatments for anxiety and insomnia. The present special issue consists of series of five papers covering current issues in the area of benzodiazepine side effects. These reviews cover a wide range of topics pertaining to adverse, unintended consequences of this class of pharmacologic agents including their potential for tolerance and withdrawal, their profile of associated cognitive impairments, as well as current understanding of means for minimizing these unintended effects. The reviews also cover a variety of methodologies and disciplines from laboratory-based research findings with animals, to laboratory-based studies with healthy human volunteers, to findings obtained in the clinic with anxious patients. All reviews are timely contributions, covering highly relevant topics for consideration of benzodiazepine side effects at present. The papers presented herein should serve to stimulate future research that may ultimately help improve the quality of life of those patients living with debilitating anxiety-related conditions.

As-needed use of benzodiazepines in managing clinical anxiety: incidence and implications.

Benzodiazepines (BZs) have been widely investigated in terms of clinical efficacy, factors underlying dependence, associated cognitive impairments, and interactions with psychotherapy for anxiety control. However, few studies have systematically considered manner of BZ administration in relation to these variables. Studies of chronic BZ users indicate that as-needed or p.r.n. use is a very common practice, increases with chronicity of BZ use, and is preferred compared to regularly scheduled BZ administration. Moreover, a recent study of physician prescription practices indicated that p.r.n. BZ use is a commonly recommended BZ use regimen for anxiety disorder management. Physician advocates of p.r.n. BZ prescriptions for anxiety disorders cite enhanced patient control over symptoms, facilitation of exposure to fear-provoking situations, and reduced frequency of use as rationales supporting this practice. Available data however, do not consistently support these hypothesized advantages of p.r.n. BZ use. And in general, findings from different investigations relevant to this question suggest that p.r.n. BZ administration may be associated with increased patient preference for BZs over placebo, continued use, and greater impairment on cognitive factors associated with positive long-term anxiety management. Ironically, p.r.n. BZ administration may also be associated with reduced anxiolytic efficacy over time. These suggestive findings argue for greater systematic investigation of manner of BZ administration as an important medication use parameter. Such investigations may also yield practical guidelines for navigating BZ discontinuation and promoting more successful long-term management of anxiety.

A method for the determination of volatile ammonia in air, using a nitrogen-cooled trap and fluorometric detection.

A quick, cheap, and accurate method for the determination of ammonia in air is described. Ammonia and water vapor are trapped simultaneously in a gas sampling tube cooled in liquid nitrogen. Subsequently ammonia is derivatized with o-phthaldialdehyde and determined using fluorescence detection. The detection limit of ammonia in a gaseous sample is about 1 nmol per liter of gas. The recovery, using a calibration gas of 6.00 ppm ammonia in nitrogen, is 102.9 +/- 6.4%. Examples are presented in which this method is used for the determination of ammonia in environmental air and in expired air during exhaustive exercise of a human subject. It is suggested that this method can be used for the determination of volatile ammonia and other compounds in air during environmental and biological monitoring and in research.

A model for regulation of the Mg(2+)-stimulated acto-myosin-ATPase activity: inhibition of the formation of actin-myosin complex and the Mg( 2+)-stimulated acto-myosin-ATPase activity by IMP and AMP.

Previously, we showed that the decrease in force output during continuous isometric contractions in rat skeletal muscle was related to an increase in the concentration of IMP. In this paper we report on additional experiments in which the effect of IMP on the Mg(2+)-stimulated acto-myosin-ATPase activity of isolated actin and myosin is measured at 35 degrees C. The results show that 1) the binding of actin to myosin is co-operative (Hill coefficient = 3.82); 2) in the presence of IMP or AMP the Mg(2+)-stimulated acto-myosin-ATPase activity is inhibited up to 60% at 10 mM; 3) in the presence of IMP or AMP not only the Mg(2+)-stimulated acto-myosin-ATPase activity decreases, but also K(50). From these results we conclude that IMP and AMP may be considered as uncompetitive inhibitors. Our results suggest that IMP and AMP can prevent an 'energy crisis' during exhaustive exercise of short duration by down-regulating the contractile machinery.

Reactivation of latent bovine herpesvirus 1 in cattle seronegative to glycoproteins gB and gE.

Six heifers were vaccinated intranasally with the live bovine herpesvirus 1 (BHV1) temperature-sensitive (ts) vaccine strain RBL106 within 3 weeks of birth. These calves most likely still had maternal antibodies against BHV1. Thereafter, these heifers were vaccinated several times with an experimental BHV1 glycoprotein-D (gD) subunit vaccine. At the age of 3 years these 6 heifers were seronegative in the BHV1 gB and gE blocking ELISAs, but had neutralizing antibodies against BHV1, probably induced by the vaccinations with the gD subunit vaccine. Five of these 6 heifers excreted BHV1 after treatment with dexamethasone. Restriction enzyme analysis of the genome of the excreted viruses revealed that all 5 isolates had a BHV1.1 genotype and that isolates of 3 heifers were not obviously different from the ts-vaccine strain. The restriction enzyme fragment pattern of the isolate of 1 heifer was clearly different from the pattern of the ts-vaccine strain. It is concluded that cattle can be seronegative against BHV1 gB and gE but can still carry BHV1 in a latent form. This finding strongly suggests that there are completely BHV1 seronegative cattle that are latently infected with BHV1. The impact of this finding on BHV1 eradication programmes is discussed.

Cognitive behavioural therapy and pharmacotherapy: complementary or contradictory approaches to the treatment of anxiety?

Considerable controversy exists regarding the practice of combining Cognitive Behavioural Therapy (CBT) with Pharmacotherapy (PT) in the management of anxiety. This paper considers whether these two forms of treating anxiety disorders can be effectively combined to enhance treatment outcome. Despite the theoretical appeal of a combined approach, a critical review of treatment outcome findings across CBT and various anxiolytic medications and their combination, suggests a failure of these treatments to operate in a complementary fashion. A detrimental impact of anxiolytic medication on CBT outcome is particularly salient for high potency benzodiazepines. Low potency benzodiazepines and antidepressants generally have a negligible impact with no clear evidence of treatment enhancement and some negative combined treatment effects on medication withdrawal and at long-term follow-up. Thus, we address potential mechanisms that may explain this treatment noncomplementarity and in some cases, treatment incompatibility. Cognitive factors influencing treatment outcome (catastrophic beliefs, self-efficacy, selective attention, and memory) are highlighted in view of the empirically supported mediating role of these variables in accounting for treatment responsiveness. Potential effects of anxiolytic medication on cognitive change in CBT are postulated. A number of suggestions for future research and clinical practice are proposed on the basis of this review.

Cognitive content specificity in selective attention across four domains of maladjustment.

This research provided a rigorous examination of content-specific selective attention effects across the maladjustment domains of depression, anxiety, bulimia, and Type A behaviour. Study 1 utilized a self-referent endorsement task to obtain a set of empirically validated stimulus adjectives related to each maladjustment domain for use in the attentional paradigm in Study 2. Moreover, Study 1 provided some initial support for content-specificity proposals at the self-schema level Self-descriptive ratings in Study 1 indicated that depressed individuals uniquely identified themselves with adjectives relating to hopelessness, loss and failure. In contrast, the unique self-descriptive adjectives of anxious individuals centered on themes of social threat. Bulimics, in turn, endorsed unique self-descriptors relating to food and weight issues, whereas Type A self-descriptions were uniquely associated with achievement concerns. Content-specificity effects for selective attention were obtained in Study 2 for three of the four domains of interest (i.e. depression anxiety, and bulimia). Using a modified probe detection task, and very stringent criteria for group classification, it was found that individuals in each of these three groups selectively attended to personal adjectives that were hypothesized to be of specific relevance to their underlying cognitive concerns. Limited content-specificity effects were obtained for an incidental recognition measure, with only the depressed and bulimic groups showing enhanced memory performance for personal adjectives uniquely related to their dominant self-views. These findings are discussed in terms of various content-specificity distinctions across the four domains of maladjustment, including possible implications for the expression of differential behaviours for each domain.

The validity of the use of heart rate in estimating oxygen consumption in static and in combined static/dynamic exercise.

The accuracy of using the HR/VO2 relation determined in running to predict VO2 from HR in tasks involving static and combined static/dynamic exercise was examined in a group of 8 healthy subjects (age 20-27 years). The HR measured in weight-holding tasks (with static exercise) and weight-carrying tasks (with combined static/dynamic exercise) with weights varying from 4-12 kg was inserted into the linear relation between HR and VO2 in the running task (dynamic exercise). The predicted VO2 was compared with measured value. The conclusions were as follows. It is not accurate to use a simple dynamic task to predict VO2 from a measured HR in static work. The percentage differences vary between 78 and 186%. In combined static-dynamic work a simple dynamic task can be accurately used to predict VO2 from measured HR, while carrying small weights (4, 8 and 10 kg). However, more static work (12 kg) makes the estimations poorer with a significant percentage difference in VO2 of 38%.

Anaerobic chemical changes and mechanical output during isometric tetani of rat skeletal muscle in situ.

The time course was examined of the energy-rich phosphate usage and exerted isometric tetanic force in electrically stimulated rat quadriceps muscle. The maximal rate of energy-rich phosphate usage was calculated from the changes in the intramuscular concentrations of phosphocreatine, lactate, ATP and inosine monophosphate (IMP) and was somewhat higher than those calculated on the basis of exercise in vivo. The IMP concentration increased directly from the onset of the contraction until after about 11 s it remained constant. The increase in the IMP concentration coincided with a decrease in the ATP concentration. The relationship between mechanical output and energy usage was examined in two ways (i) by calculating the ratio time integral of the force (FTI) and the total energy-rich usage (Ptot) and (ii) by calculating the ratio Force (Ft) to the energy flux (dPtot/dt) at a certain time t. Whereas the ratio FTI/Ptot showed a hyperbolic relationship, the ratio Ft/(dPtot/dt) showed a parabolic relationship. From the latter finding and from the results described in the literature it is concluded that the ratio mechanical output/energy-rich phosphate usage depends on the conditions under which exercise is carried out. Recovery under aerobic conditions from a maximal tetanic isometric contraction sustained for 15 s was slow compared to results of experiments in vivo.

Influence of muscle dimensions on economy of isometric exercise in rat medial gastrocnemius muscles in situ.

The effect of muscle dimensions on economy (force-time integral divided by the amount of energy utilized) was investigated in male rats (body mass range 95-490 g), anaesthetized with pentobarbital. The medial gastrocnemius muscle in situ performed 6 maximal isometric contractions of 350 ms duration (1.s-1) at twitch optimum length at 35 degrees C. The areas under the 6 time-force curves were added to obtain force-time integral of the experiment. Differences of concentrations of ATP, phosphocreatine and lactate between experimental and contralateral (resting) muscles were used to calculate high-energy phosphate consumption due to stimulation. Muscle mass and cross-sectional area increased (approximately +400% and +300%, respectively) over the rat body mass range studied. Muscle length and length of the most distal fibre bundle increased by approximately 17 mm and 4 mm, respectively. Force-time integral (N.s) increased proportional to cross-sectional area whereas high-energy phosphate consumption (mumoles) increased proportional to muscle mass. The relative fraction of the total energy consumption utilized for force-independent processes was independent of rat body mass. The economy of the actomyosin system was unaffected during growth, whereas economy of the whole muscle decreased during growth by approximately 30% (p less than 0.001). The effect of muscle dimensions on economy is discussed with respect to human endurance capacity measured by voluntary isometric contractions.

IMP production and energy metabolism during exercise in rats in relation to age.

IMP production in and force exerted by rat quadriceps muscle in situ during various types of exercise were examined in relation to age. During continuous isometric exercise with constant stimulation time, the amount of IMP was linearly and inversely related to the age of the animals; a higher IMP concentration was found in intermittent isometric and dynamic exercise. No relationship was found between the total AMP deaminase activity and age. Exercise influenced neither the total activity nor the activity in the soluble fraction. From the results it is concluded that: the IMP concentration is linearly related to the free intracellular ATP4-/ADP3- ratio and the free AMP2- concentration; older animals are better able to maintain a high intramuscular ATP4-/ADP3- ratio and a low AMP2- concentration; IMP is produced in particular under conditions when the muscle has to work under extreme stress. IMP possibly exerts a feed-back control on the contraction system.