Individual differences in neural correlates of fear conditioning as a function of 5-HTTLPR and stressful life events

Fear learning is a crucial process in the pathogeneses of psychiatric disorders, which highlights the need to identify specific factors contributing to interindividual variation. We hypothesized variation in the serotonin transporter gene (5-HTTLPR) and stressful life events (SLEs) to be associated with neural correlates of fear conditioning in a sample of healthy male adults (n = 47). Subjects were exposed to a differential fear conditioning paradigm after being preselected regarding 5-HTTLPR genotype and SLEs. Individual differences in brain activity as measured by functional magnetic resonance imaging (fMRI), skin conductance responses and preference ratings were assessed. We report significant variation in neural correlates of fear conditioning as a function of 5-HTTLPR genotype. Specifically, the conditioned stimulus (CS⁺) elicited elevated activity within the fear-network (amygdala, insula, thalamus, occipital cortex) in subjects carrying two copies of the 5-HTTLPR S′ allele. Moreover, our results revealed preliminary evidence for a significant gene-by-environment interaction, such as homozygous carriers of the 5-HTTLPR S′ allele with a history of SLEs demonstrated elevated reactivity to the CS⁺ in the occipital cortex and the insula. Our findings contribute to the current debate on 5-HTTLPR x SLEs interaction by investigating crucial alterations on an intermediate phenotype level which may convey an elevated vulnerability for the development of psychopathology.     

Hypo- and hyperglycemia predict outcome in patients with left ventricular dysfunction after acute myocardial infarction: data from EPHESUS

BackgroundHyperglycemia predicts death in cardiovascular disease, but intensive glucose-lowering strategies increase mortality rates in diabetes. The present analysis investigated the prognostic value of postadmission blood glucose (BG) concentration on clinical outcomes in high-risk patients with heart failure after acute myocardial infarction.Methods and ResultsA total of 6,496 patients from the Eplerenone Post–Acute Myocardial Infarction Heart Failure Efficacy and Survival Study (EPHESUS) were categorized into 4 groups by plasma glucose concentration: ≤4.5 mmol/L (hypoglycemia), 4.5–5.5 mmol/L (normoglycemia), 5.5–8.3 mmol/L (elevated glucose level), and >8.3 mmol/L (severe hyperglycemia). We evaluated the time to all-cause death (primary end point) and time to cardiovascular death or hospitalization (secondary end point). Hypo- and severe hyperglycemia were prevalent in 509 (8%) and 1,588 (24%) patients, respectively. There was a U-shaped relationship between BG level and incidence of all-cause death (11.8% in patients with normoglycemia vs 15.1% and 19.9% in those with hypo- and severe hyperglycemia; P < .001). The incidence of the secondary end point was increased only in hyperglycemic patients (36% vs 23% in normoglycemic patients; P < .001). In multivariate Cox regression analysis, hypoglycemia (hazard ratio [HR] 1.38, 95% confidence interval [CI] 1.06–1.81; P = .002) and severe hyperglycemia (HR 1.52, CI 1.27–1.83; P < .0001) proved to be strong predictors of all-cause death. There was no significant interaction between eplerenone treatment and blood glucose levels regarding clinical outcomes.ConclusionsIn heart failure after acute myocardial infarction, both hypo- and hyperglycemia at the postacute phase identify patients with increased risk of death during long-term follow-up.     

MicroRNA expression profiling of carcinoma in situ cells of the testis

Testicular germ cell tumours, seminoma (SE) and non-seminoma (NS), of young adult men develop from a precursor cell, carcinoma in situ (CIS), which resembles foetal gonocytes and retains embryonic pluripotency. We used microarrays to analyse microRNA (miRNA) expression in 12 human testis samples with CIS cells and compared it with miRNA expression profiles of normal adult testis, testis with Sertoli-cell-only that lacks germ cells, testis tumours (SE and embryonal carcinoma (EC), an undifferentiated component of NS) and foetal male and female gonads. Principal components analysis revealed distinct miRNA expression profiles characteristic for each of the different tissue types. We identified several miRNAs that were unique to testis with CIS cells, foetal gonads and testis tumours. These included miRNAs from the hsa-miR-371-373 and -302-367 clusters that have previously been reported in germ cell tumours and three miRNAs (hsa-miR-96, -141 and -200c) that were also expressed in human epididymis. We found several miRNAs that were upregulated in testis tumours: hsa-miR-9, -105 and -182-183-96 clusters were highly expressed in SE, while the hsa-miR-515-526 cluster was high in EC. We conclude that the miRNA expression profile changes during testis development and that the miRNA profile of adult testis with CIS cells shares characteristic similarities with the expression in foetal gonocytes.     

Influence of peritoneal dialysis solution on measurements of fluid status by bioimpedance spectroscopy

Purpose and methods

The accurate estimation of volume status is a central problem in dialysis patients. Recently, a bioimpedance spectroscopy (BIS) device (BCM Body Composition Monitor FMC, Germany) has attained growing interest in this regard. By processing the raw data for extracellular water (ECW) and intracellular water (ICW) by means of a validated body composition model, this device allows a quantification of the individual fluid overload (FO) compared to a representative healthy population. In this study, we addressed the issue whether the presence of peritoneal dialysate has an impact on measurements of FO by BIS in PD patients.

Results

Forty-two BIS measurements using the BCM device were performed both in the absence (D?) and presence (D+) of peritoneal dialysate in 17 stable PD patients. Data for ECW, ICW and FO (D+; D?) were analyzed by paired t test and linear regression. Mean FO was 0.99 ± 1.17 L in D? and 0.94 ± 1.27 in D+ (p = n.s. paired t test). Linear regression demonstrated an excellent degree of conformity between FO (D?) and FO (D+) (r ² = 0.93).

Conclusion

The presence of peritoneal fluid in PD patients has a negligible influence on measurements of FO by BIS. The BIS measurements can be therefore conveniently and reliably done without emptying the peritoneal cavity; this may facilitate the use of BIS in this particular group of patients.     

Estimation of Glomerular Podocyte Number: A Selection of Valid Methods

The podocyte depletion hypothesis has emerged as an important unifying concept in glomerular pathology. The estimation of podocyte number is therefore often a critical component of studies of progressive renal diseases. Despite this, there is little uniformity in the biomedical literature with regard to the methods used to estimate this important parameter. Here we review a selection of valid methods for estimating podocyte number: exhaustive enumeration method, Weibel and Gomez method, disector/Cavalieri combination, disector/fractionator combination, and thick-and-thin section method. We propose the use of the disector/fractionator method for studies in which controlled sectioning of tissue is feasible, reserving the Weibel and Gomez method for studies based on archival or routine pathology material.Podocytes play a key role in the preservation of normal glomerular structure and function.¹ Podocyte loss has been associated with progression of glomerular diseases both in humans^2,3 and in experimental models of glomerular injury.^4–6 The assessment of podocyte number in human renal biopsy samples and in kidney specimens from animal models may therefore be a pivotal component of studies of the pathogenesis and treatment of glomerular disease. Despite this, there is little uniformity in the biomedical literature with regard to the methods used for estimating podocyte number either in experimental models or clinical biopsy specimens. As a result, estimates of podocyte number can vary widely between studies, making meaningful comparisons difficult.The glomerulus and the cells within it are three-dimensional objects. Quantitative assessment of these structures, on the other hand, has traditionally involved measurements on two-dimensional images from histologic sections. Stereology is a body of mathematical/statistical theory and methods wherein three-dimensional characteristics of objects are estimated from lower-dimensional images of those objects. Although stereology is a well developed field, as with other forms of statistically based reasoning, its results can sometimes seem counterintuitive. At the same time, apparently common-sense approaches to the estimation of quantitative structural variables, such as podocyte number, often lack stereologic validity and, as a result, introduce biologic uncertainty.In this review we describe five methods for estimating podocyte number, examine their assumptions and limitations, and indicate some of the circumstances under which they may represent appropriate approaches. These methods occupy a range of increasingly general assumptions and corresponding changes in methodologic design. The main body of this paper provides an overview and motivation for these five methods (the Supplemental Material describes the methods with worked examples in more detail). We also present one example of a commonly used but invalid method and illustrate its shortcomings.     

Use of Computer-Assisted Technologies (CAT) to Enhance Social, Communicative, and Language Development in Children with Autism Spectrum Disorders

Major advances in multimedia computer technology over the past decades have made sophisticated computer games readily available to the public. This, combined with the observation that most children, including those with autism spectrum disorders (ASD), show an affinity to computers, has led researchers to recognize the potential of computer technology as an effective and efficient tool in research and treatment. This paper reviews the use of computer-assisted technology (CAT), excluding strictly internet-based approaches, to enhance social, communicative, and language development in individuals with ASD by dividing the vast literature into four main areas: language, emotion recognition, theory of mind, and social skills. Although many studies illustrate the tremendous promise of CAT to enhance skills of individuals with ASD, most lack rigorous, scientific assessment of efficacy relative to non-CAT approaches.     

Genetic fate mapping of type‐1 stem cell‐dependent increase in newborn hippocampal neurons after electroconvulsive seizures

Electroconvulsive therapy (ECT) is a uniquely effective treatment for major depressive disorder. An increase in hippocampal neurogenesis is implicated in the recovery from depression. We used an inducible genetic mouse model in which only GFAP‐expressing stem‐like cells (type‐1 cells) and their progeny are selectively labeled with the reporter protein β‐galactosidase to track the process of neurogenesis in the dentate gyrus over 3 months following electroconvulsive seizures (ECS), the mouse equivalent of ECT. All ECS protocols tested induced a transient increase in type‐1 cell divisions. While this led to an expansion of the type‐1 cell pool after high‐frequency ECS sessions for 5 consecutive days (5‐ECS), asymmetric divisions drove neurogenesis by giving rise to Doublecortin (DCX)‐expressing neuroblasts that matured into NeuN+ neurons. Significantly, the increase in newly generated DCX+ and NeuN+ cells after 5‐ECS could be traced back to proliferating type‐1 cells. Low‐frequency continuation ECS (c‐ECS) consisting of five single ECS sessions administered every 2 weeks resulted in a similar increase in newborn neurons as the high‐frequency 5‐ECS protocol. Moreover, the combination of 5‐ECS and c‐ECS led to a further significant increase in newborn neurons, suggesting a cellular mechanism responsible for the propitious effects of high‐frequency ECT followed by continuation ECT in severely depressed patients. The ability of high‐ and low‐frequency ECS to induce normally quiescent type‐1 cells to proliferate and generate new neurons sets it apart from other antidepressant treatments and may underlie the superior clinical efficacy of ECT. © 2013 Wiley Periodicals, Inc.