The AVP Deficit in LAB Mice:

The increased incidence of psychiatric disorders, such as anxiety disorders and depression, makes a strengthened search of genetic and environmental causal factors essential. Besides clinical studies, the broad preclinical research identifies continuously involved neuronal circuits, proteins, and genes representing new candidates in the progress of pharmacological research and the development of new therapies. In this context, an animal model of extremes in trait anxiety, simulating pathologic anxiety, was generated to investigate the neuronal and genetic basis. Thus, CD1 mice selectively and bi-directionally inbred concerning their anxiety-related behavior form two lines, the high (HAB) and the low (LAB) anxiety-related behavior mice. The two lines display, after 24 generations, robust differences in trait anxiety and, additionally, in depression-like behavior, reflecting the clinical comorbidity of anxiety and depression, both of which are potentially based on a few selected genes in the two lines. The peptide arginine-vasopressin (AVP) is one factor found to be differentially expressed between the two mouse lines. In the present manuscript its involvement in the behavioral phenotype is scrutinized. As the antidiuretic hormone, AVP expressed in the hypothalamic paraventricular nucleus (PVN) and the supraoptic nucleus is well known to regulate peripherally the body water balance. Therefore, the physiological consequence of the differences in Avp expression was analyzed, uncovering signs of central diabetes insipidus in LAB mice, an AVP deficit-related disease in humans. Symptoms also seen in LAB mice are increased daily fluid intake and high amounts of highly diluted urine as a result of the inability to secrete enough AVP in the blood circulation. Besides the antidiuretic function, AVP of the PVN is potentially involved in emotionality-related behaviors and further in the regulation of the hypothalamo-pituitary-adrenocortical axis, the neuroendocrine stress response. Thus, the peripherally observable strong deficit in AVP might also be present in the brain of LAB mice, causing a dysregulation of anxiety-related behavior in these animals. Indeed, the less anxious LAB mice exhibit less releasable AVP in the PVN compared to HAB and “normal” CD1 mice, supporting the role of AVP as a crucial regulatory factor of emotionality Besides the genetic predisposition, environmental factors, especially maternal and social interactions after birth, display a significant parameter in shaping the genetically given behavioral traits in emotionality. Therefore, we tested the maternal rearing behavior of HAB and LAB dams for differences possibly involved in the development of the two phenotypes. As dams of the two lines differ in their nursing style with LAB mothers showing less arched back nursing, a posture associated with the quality of maternal investment, we cross-fostered pups of the two lines to quantify the maternal influence on the anxiety- and stress-related phenotype of HAB and LAB mice. As we found just slight shifts in some parameters still within the range of the HAB and LAB phenotype, the two breeding lines can be defined as mainly genetically distinct, providing a beneficial tool to identify genes responsible for pathologic alterations in human diseases

Evaluation of a novel quantitative canine species-specific point-of-care assay for C-reactive protein

Background: Species-specific point-of-care tests (POCT) permit a rapid analysis of canine C-reactive protein (CRP), enabling veterinarians to include CRP in clinical decisions. Aim of the study was to evaluate a novel POCT for canine CRP (Point Stripâ TM Canine CRP Assay) run on a small in-house-analyzer (Point Reader TM V) using lithium heparin plasma and to compare assay performance to an already established canine CRP assay (Gentian Canine CRP Immunoassay) run on two different bench top analyzers serving as reference methods (ABX Pentra 400, AU 5800). Linearity was assessed by stepwise dilution of plasma samples with high CRP concentrations. Limit of quantification (LoQ) was determined by repeated measurements of samples with low CRP concentrations. Coefficient of variation (CV) at low (10-50 mg/l), moderate (50-100 mg/l), and high (100-200 mg/l) CRP concentrations was investigated as well as possible interferences. Method comparison study was performed using 45 samples of healthy and diseased dogs. Quality criteria were fulfilled if the total observed error (TEobs=2CV%+bias%) was below the minimal total allowable error of 44.4% (TE min). Additionally, a reference range (n =60 healthy dogs) was established. Results: Linearity was present at CRP concentrations of 10-132 mg/l (&#8793; 361 mg/l CRP with reference method) with a LoQ set at 10 mg/l. At moderate to high CRP concentrations, intra- and inter-assay CVs were< =8% and <=11% respectively, while CVs<=22% and <=28% were present at low concentrations. No interferences were observed at concentrations of 4 g/l hemoglobin, 800 mg/l bilirubin and 8 g/l triglycerides. Method comparison study demonstrated an excellent correlation with both reference methods (r =0.98 for ABX Pentra 400; 0.99 for AU 5800), though revealing a proportional bias of 19.7% (ABX Pentra 400) and 10.7% (AU 5800) respectively. TEobs was 26.7-31.9% and 16.7-21.9% and thus < TEmin. Healthy dogs presented with CRP values <=11.9 mg/l. Conclusions The POCT precisely detects canine CRP at clinically relevant moderate and high CRP concentrations. The assay correlates well with both reference methods. Due to the bias, however, follow-up examinations should be performed with the same assay and analyzer

A Hypomorphic Vasopressin Allele Prevents Anxiety-Related Behavior

To investigate neurobiological correlates of trait anxiety, CD1 mice were selectively bred for extremes in anxiety-related behavior, with high (HAB) and low (LAB) anxiety-related behavior mice additionally differing in behavioral tests reflecting depression-like behavior. promoter deletion to anxiety-related behavior. gene promoter explains gene expression differences in association with the observed phenotype, thus further strengthening the concept of the critical involvement of centrally released AVP in trait anxiety

Evaluation of a novel quantitative canine species-specific point-of-care assay for C-reactive protein

Abstract Background Species-specific point-of-care tests (POCT) permit a rapid analysis of canine C-reactive protein (CRP), enabling veterinarians to include CRP in clinical decisions. Aim of the study was to evaluate a novel POCT for canine CRP (Point Strip™ Canine CRP Assay) run on a small in-house-analyzer (Point Reader™ V) using lithium heparin plasma and to compare assay performance to an already established canine CRP assay (Gentian Canine CRP Immunoassay) run on two different bench top analyzers serving as reference methods (ABX Pentra 400, AU 5800). Linearity was assessed by stepwise dilution of plasma samples with high CRP concentrations. Limit of quantification (LoQ) was determined by repeated measurements of samples with low CRP concentrations. Coefficient of variation (CV) at low (10–50 mg/l), moderate (50–100 mg/l), and high (100–200 mg/l) CRP concentrations was investigated as well as possible interferences. Method comparison study was performed using 45 samples of healthy and diseased dogs. Quality criteria were fulfilled if the total observed error (TEobs = 2CV% + bias%) was below the minimal total allowable error of 44.4% (TE min). Additionally, a reference range (n = 60 healthy dogs) was established. Results Linearity was present at CRP concentrations of 10–132 mg/l (≙ 361 mg/l CRP with reference method) with a LoQ set at 10 mg/l. At moderate to high CRP concentrations, intra- and inter-assay CVs were ≤ 8% and ≤ 11% respectively, while CVs ≤ 22% and ≤ 28% were present at low concentrations. No interferences were observed at concentrations of 4 g/l hemoglobin, 800 mg/l bilirubin and 8 g/l triglycerides. Method comparison study demonstrated an excellent correlation with both reference methods (r = 0.98 for ABX Pentra 400; 0.99 for AU 5800), though revealing a proportional bias of 19.7% (ABX Pentra 400) and 10.7% (AU 5800) respectively. TEobs was 26.7–31.9% and 16.7–21.9% and thus < TEmin. Healthy dogs presented with CRP values ≤11.9 mg/l. Conclusions The POCT precisely detects canine CRP at clinically relevant moderate and high CRP concentrations. The assay correlates well with both reference methods. Due to the bias, however, follow-up examinations should be performed with the same assay and analyzer

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The endocrine stress response is linked to one specific locus on chromosome 3 in a mouse model based on extremes in trait anxiety

<p>Abstract</p> <p>Background</p> <p>The hypothalamic-pituitary-adrenal (HPA) axis is essential to control physiological stress responses in mammals. Its dysfunction is related to several mental disorders, including anxiety and depression. The aim of this study was to identify genetic loci underlying the endocrine regulation of the HPA axis.</p> <p>Method</p> <p>High (HAB) and low (LAB) anxiety-related behaviour mice were established by selective inbreeding of outbred CD-1 mice to model extremes in trait anxiety. Additionally, HAB <it>vs.</it> LAB mice exhibit comorbid characteristics including a differential corticosterone response upon stress exposure. We crossbred HAB and LAB lines to create F1 and F2 offspring. To identify the contribution of the endocrine phenotypes to the total phenotypic variance, we examined multiple behavioural paradigms together with corticosterone secretion-based phenotypes in F2 mice by principal component analysis. Further, to pinpoint the genomic loci of the quantitative trait of the HPA axis stress response, we conducted genome-wide multipoint oligogenic linkage analyses based on Bayesian Markov chain Monte Carlo approach as well as parametric linkage in three-generation pedigrees, followed by a two-dimensional scan for epistasis and association analysis in freely segregating F2 mice using 267 single-nucleotide polymorphisms (SNPs), which were identified to consistently differ between HAB and LAB mice as genetic markers.</p> <p>Results</p> <p>HPA axis reactivity measurements and behavioural phenotypes were represented by independent principal components and demonstrated no correlation. Based on this finding, we identified one single quantitative trait locus (QTL) on chromosome 3 showing a very strong evidence for linkage (2ln (L-score) > 10, LOD > 23) and significant association (lowest Bonferroni adjusted p < 10^-28) to the neuroendocrine stress response. The location of the linkage peak was estimated at 42.3 cM (95% confidence interval: 41.3 - 43.3 cM) and was shown to be in epistasis (p-adjusted < 0.004) with the locus at 35.3 cM on the same chromosome. The QTL harbours genes involved in steroid synthesis and cardiovascular effects.</p> <p>Conclusion</p> <p>The very prominent effect on stress-induced corticosterone secretion of the genomic locus on chromosome 3 and its involvement in epistasis highlights the critical role of this specific locus in the regulation of the HPA axis.</p

Allele frequency in a NAB population (n = 165) for the SNP in the <i>Avp</i> signal peptide and the strictly linked promoter deletion.

<p>Allele frequency in a NAB population (n = 165) for the SNP in the <i>Avp</i> signal peptide and the strictly linked promoter deletion.</p

Allele-specific vasopressin <i>(Avp)</i> expression.

<p>Proportion of HAB allele-specific vs. LAB allele-specific <i>Avp</i> transcripts from heterozygous F1 (HABxLAB intercross) mice in the paraventricular nucleus (PVN; χ² = 14.4 p = 1.4e-4) and the supraoptic nucleus (SON; χ² = 15.2 p = 4.8e-5). Data are shown as means+SEM; *** p<0.001.</p

Correlation between gene expression and behavior.

<p>Correlation of vasopressin <i>(Avp)</i> mRNA expression in the paraventricular nucleus (PVN) with (A) anxiety-related behavior and (B) depression-like behavior of HAB, F1 and LAB male mice under basal conditions. For corresponding immunohistochemistry, see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0005129#pone-0005129-g003" target="_blank">Fig. 3</a>.</p