Effect of repeated novel stressors on depressive behavior and brain norepinephrine receptor system in Sprague-Dawley and Wistar Kyoto (WKY) rats

This study compared the effects of repeated novel stressors on ‘depressive behaviors’, defined by the forced-swim and open-field tests, in Sprague-Dawley (S-D) and Wistar Kyoto (WKY) rats. Since stress appears to alter brain norepinephrine (NE) activity, this study also investigated the effects of the stressors on β-adrenoceptors (β-ARs),α₂-adrenoceptors (α₂-ARs) and NE transporter (NET) sites in S-D and WKY rats. Stress did not alter¹²⁵I-iodopindolol (¹²⁵I-PIN) binding to β-ARs, nor [³H]idazoxan ([³H]IDAZ) binding toα₂-ARs in S-D rats, compared to non-stressed controls. However, WKY-stressed rats showed a significant reduction in¹²⁵I-IPIN binding to β-ARs in the cortex, hippocampus, amygdala and hypothalamus, and a reduction in [³H]IDAZ binding toα₂-ARs in the amygdala. [³H]nisoxetine ([³H]NIS) binding to NET sites in WKY-stressed rats was also reduced in the cortex, hippocampus and amygdala. When both strains were compared, the most surprising finding was a significantly higher density of NET sites in the hippocampus and amygdala in WKY rats compared to S-D rats. The results of this study indicate that stress, not only exacerbates depressive behavior in WKY rats, but also selectively alters β-ARs,α₂-ARs and NET sites in limbic brain regions. Thus, the WKY strain may serve as a useful animal model for depressive behavior and for the investigation of novel antidepressant drugs.     

Genetic analysis of breast cancer progression

At the histological level, breast tumors display a variety of morphologic lesions which suggest the existence of an increasingly aberrant pathway of intermediate steps leading to the invasive primary tumor and its metastatic dissemination. In order to obtain direct evidence for this presumed progression, underlying genetic changes must be identified. Analyses of primary breast tumors have revealed a large number of dominant and recessive gene alterations encompassing several cellular attributes and activities. It is quite likely that some of these alterations are of a causal nature and thus enable the tumor to attain distinctive malignant phenotypes, such as, dysregulated proliferation, invasion, angiogenesis, and ability to metastasize. Considerable heterogeneity has been observed in the sequence of acquisition of these genetic changes, which is substantiated by recent comparative analyses between carefully microdissected preinvasive and invasive tumor. The data are evaluated here in the context of existing models of breast cancer progression. Implications and prospects for translational application to the clinic are also discussed.     

Role of nitric oxide signaling components in differentiation of embryonic stem cells into myocardial cells

Nitric oxide (NO) is involved in number of physiological and pathological events. Our previous studies demonstrated a differential expression of NO signaling components in mouse and human ES cells. Here, we demonstrate the effect of NO donors and soluble guanylyl cyclase (sGC) activators in differentiation of ES cells into myocardial cells. Our results with mouse and human ES cells demonstrate an increase in Nkx2.5 and myosin light chain (MLC2) mRNA expression on exposure of cells to NO donors and a decrease in mRNA expression of both cardiac-specific genes with nonspecific NOS inhibitor and a concomitant increase and decrease in the mRNA levels of sGC α₁ subunit. Although sGC activators alone exhibited an increase in mRNA expression of cardiac genes (MLC2 and Nkx2.5), robust inductions of mRNA and protein expression of marker genes were observed when NO donors and sGC activators were combined. Measurement of NO metabolites revealed an increase in the nitrite levels in the conditioned media and cell lysates on exposure of cells to the different concentrations of NO donors. cGMP analysis in undifferentiated stem cells revealed a lack of stimulation with NO donors. Differentiated cells however, acquired the ability to be stimulated by NO donors. Although, 3-(4-amino-5-cyclopropylpyrimidin-2-yl)-1-(2-fluorobenzyl)-1H-pyrazolo [3,4-b]pyridine (BAY 41-2272) alone was able to stimulate cGMP accumulation, the combination of NO donors and BAY 41-2272 stimulated cGMP levels more than either of the agents separately. These studies demonstrate that cGMP-mediated NO signaling plays an important role in the differentiation of ES cells into myocardial cells.     

Chest Tube Selection in Cardiac and Thoracic Surgery: A Survey of Chest Tube-Related Complications and Their Management

Abstract   Background: Blood accumulating inside chest cavities can lead to serious complications if it is not drained properly. Because life-threatening conditions can result from chest tube occlusion after thoracic surgery, large-bore tubes are generally employed to optimize patency. Aims: The aim of this study was to better define problems with current paradigms for chest drainage. Materials and Methods: A survey was conducted of North American cardiothoracic surgeons and specialty cardiac surgery nurses. A total of 108 surgeons and 108 nurses responded. Results: The survey revealed that clogging leading to chest-tube dysfunction is a major concern when choosing tube size. Of surgeons responding, 106 of 106 (100%) had observed chest tube clogging, and 93 of 106 (87%) reported adverse patient outcomes from a clogged tube. Despite techniques such as tube stripping, tapping, and squeezing, up to 51% of surveyed surgeons stated they are not satisfied with currently available tubes and procedures to avoid tube occlusion and some even forbid the stripping maneuver for fear of causing more bleeding by the negative pressures generated. In addition, respondents noted that patients experience increasing discomfort with increasing drain size. Discussion: The major reason surgeons choose large-diameter chest tubes is linked to concern about the suboptimal available methods to avoid and treat chest-tube clogging. Even though larger tubes are thought to be associated with more pain, physicians generally err on the side of caution to avoid clogging and insert tubes with larger diameters. Conclusion: Results of this survey highlight the frequent problems with clogging with current postsurgical chest drainage systems and suggest the need for innovative solutions to avoid clogging complications and overcome clinician concern and patient pain.     

Novel TSHR mutations in consanguineous families with congenital nongoitrous hypothyroidism

Objective Nonsyndromic autosomal recessively inherited nongoitrous congenital hypothyroidism (CHNG) can be caused by mutations in TSHR, PAX8, TSHB and NKX2‐5. We aimed to investigate mutational frequencies of these genes and genotype/phenotype correlations in consanguineous families with CHNG. Design Because consanguinity in individuals with a presumptive genetic condition is often an indicator of an autosomal recessive inheritance and allows firmer correlations to be established between genotype and phenotype, we planned to execute our study in consanguineous families. Patients Hundred and thirty‐nine children with CHNG phenotype born to consanguineous families. Measurements First, we investigated cases for evidence of linkage to the four known CHNG genes by microsatellite marker analysis. Mutation analysis by direct sequencing was then performed in those cases in whom linkage to the relevant candidate gene could not be excluded. In addition, in silico analysis of the predicted structural effects of TSHR mutations was performed and related to the mutation‐specific disease phenotype. Results Homozygous germline TSHR mutations were detected in six families (5%), but no mutations were detected in PAX8, TSHB and NKX2‐5. Four of TSHR mutations had not previously been described. Genotype–phenotype correlations were established and found to be related to the predicted structural effects of the mutations. Conclusions Known causative genes account for the development of CHNG only in a minority of cases, and our cohort should provide a powerful resource to identify novel causative genes and to delineate the extent of locus heterogeneity in autosomal recessively inherited CHNG.     

Securing recruitment and obtaining informed consent in minority ethnic groups in the UK

Background  

Previous health research has often explicitly excluded individuals from minority ethnic backgrounds due to perceived cultural and communication difficulties, including studies where there might be language/literacy problems in obtaining informed consent. This study addressed these difficulties by developing audio-recorded methods of obtaining informed consent and recording data. This report outlines 1) our experiences with securing recruitment to a qualitative study investigating alternative methods of data collection, and 2) the development of a standardised process for obtaining informed consent from individuals from minority ethnic backgrounds whose main language does not have an agreed written form.     

Clinical and physiologic evaluation of stellate ganglion blockade for complex regional pain syndrome type I. (Ludwig-Maximilians-University, Munich, Germany) Clin J Pain. 2001;17:94–100.

This study measured the warm, cold, heat-evoked pain threshold and the cold-evoked pain threshold in the affected area of 16 control patients and patients with complex regional pain syndrome type 1/RSD (CRPSD1) to test the hypothesis that allodynia results from an abnormality in sensory physiology. The cold-evoked pain threshold in patients with CRPSD1/RSD was significantly decreased when compared with the thresholds in control patients (ie, a smaller decrease in temperature was necessary to elicit cold-pain in patients with CRPSD1/RSD than in control patients). The heat-evoked pain threshold in patients with CRPSD1/RSD was decreased significantly when compared with thresholds in control patients. The warm-detection and cold-detection thresholds in patients with CRPS1/RSD were similar to the thresholds in control patients. Conclude that the study suggests that thermal allodynia in patients with CRPS1/RSD resulted from decreased cold-evoked and heat-evoked pain thresholds. The thermal pain thresholds are reset so that non-noxious thermal stimuli are perceived to be pain (allodynia).     

Autozygosity mapping of Bardet-Biedl syndrome to 12q21.2 and confirmation of FLJ23560 as BBS10

Bardet-Biedl syndrome (BBS) is a genetically heterogeneous autosomal recessive disorder characterized by variable obesity, pigmentary retinopathy, polydactyly, mental retardation, hypogonadism and renal failure. In order to identify novel BBS loci we undertook autozygosity mapping studies using high-density SNP microarrays in consanguineous kindreds. We mapped a BBS locus to a 10.1 Mb region at 12q15-q21.2 in a large Omani BBS family (peak lod score 8.3 at theta = 0.0 for marker D12S1722) that contained the recently described BBS10 locus. Mutation analysis of candidate genes within the target interval, including the BBS10 gene, revealed a homozygous frameshift mutation in FLJ23560 and mutations were also detected in four smaller consanguineous families with regions of autozygosity at 12q21.2. These findings (a) confirm a previous report that FLJ23560 (BBS10) mutations are a significant cause of BBS, and (b) further demonstrate the utility of high-density SNP array mapping in consanguineous families for the mapping and identification of recessive disease genes.