Muscle Fiber Viability, a Novel Method for the Fast Detection of Ischemic Muscle Injury in Rats

Acute lower extremity ischemia is a limb- and life-threatening clinical problem. Rapid detection of the degree of injury is crucial, however at present there are no exact diagnostic tests available to achieve this purpose. Our goal was to examine a novel technique - which has the potential to accurately assess the degree of ischemic muscle injury within a short period of time - in a clinically relevant rodent model. Male Wistar rats were exposed to 4, 6, 8 and 9 hours of bilateral lower limb ischemia induced by the occlusion of the infrarenal aorta. Additional animals underwent 8 and 9 hours of ischemia followed by 2 hours of reperfusion to examine the effects of revascularization. Muscle samples were collected from the left anterior tibial muscle for viability assessment. The degree of muscle damage (muscle fiber viability) was assessed by morphometric evaluation of NADH-tetrazolium reductase reaction on frozen sections. Right hind limbs were perfusion-fixed with paraformaldehyde and glutaraldehyde for light and electron microscopic examinations. Muscle fiber viability decreased progressively over the time of ischemia, with significant differences found between the consecutive times. High correlation was detected between the length of ischemia and the values of muscle fiber viability. After reperfusion, viability showed significant reduction in the 8-hour-ischemia and 2-hour-reperfusion group compared to the 8-hour-ischemia-only group, and decreased further after 9 hours of ischemia and 2 hours of reperfusion. Light- and electron microscopic findings correlated strongly with the values of muscle fiber viability: lesser viability values represented higher degree of ultrastructural injury while similar viability results corresponded to similar morphological injury. Muscle fiber viability was capable of accurately determining the degree of muscle injury in our rat model. Our method might therefore be useful in clinical settings in the diagnostics of acute ischemic muscle injury

Listeria monocytogenes in Milk Products

peer-reviewedMilk and milk products are frequently identified as vectors for transmission of Listeria monocytogenes. Milk can be contaminated at farm level either by indirect external contamination from the farm environment or less frequently by direct contamination of the milk from infection in the animal. Pasteurisation of milk will kill L. monocytogenes, but post-pasteurisation contamination, consumption of unpasteurised milk and manufacture of unpasteurised milk products can lead to milk being the cause of outbreaks of listeriosis. Therefore, there is a concern that L. monocytogenes in milk could lead to a public health risk. To protect against this risk, there is a need for awareness surrounding the issues, hygienic practices to reduce the risk and adequate sampling and analysis to verify that the risk is controlled. This review will highlight the issues surrounding L. monocytogenes in milk and milk products, including possible control measures. It will therefore create awareness about L. monocytogenes, contributing to protection of public health

A systematic review of physiological methods in rodent pharmacological MRI studies

Rationale: Pharmacological magnetic resonance imaging (phMRI) provides an approach to study effects of drug challenges on brain processes. Elucidating mechanisms of drug action helps us to better understand the workings of neurotransmitter systems, map brain function or facilitate drug development. phMRI is increasingly used in preclinical research employing rodent models; however, data interpretation and integration are complicated by the use of different experimental approaches between laboratories. In particular, the effects of different anaesthetic regimes upon neuronal and haemodynamic processes and baseline physiology could be problematic. Objectives: This paper investigates how differences in phMRI research methodologies are manifested and considers associated implications, placing particular emphasis on choice of anaesthetic regimes. Methods: A systematic review of rodent phMRI studies was conducted. Factors such as those describing anaesthetic regimes (e.g. agent, dosage) and parameters relating to physiological maintenance (e.g. ventilatory gases) and MRI method were recorded. Results: We identified 126 eligible studies and found that the volatile agents isoflurane (43.7 %) and halothane (33.3 %) were most commonly used for anaesthesia, but dosage and mixture of ventilatory gases varied substantially between laboratories. Relevant physiological parameters were usually recorded, although 32 % of studies did not provide cardiovascular measures. Conclusions: Anaesthesia and animal preparation can influence phMRI data profoundly. The variation of anaesthetic type, dosage regime and ventilatory gases makes consolidation of research findings (e.g. within a specific neurotransmitter system) difficult. Standardisation of a small(er) number of preclinical phMRI research methodologies and/or increased consideration of approaches that do not require anaesthesia is necessary to address these challenges

Cellular dissection of psoriasis for transcriptome analyses and the post-GWAS era

Abstract Background Genome-scale studies of psoriasis have been used to identify genes of potential relevance to disease mechanisms. For many identified genes, however, the cell type mediating disease activity is uncertain, which has limited our ability to design gene functional studies based on genomic findings. Methods We identified differentially expressed genes (DEGs) with altered expression in psoriasis lesions (n = 216 patients), as well as candidate genes near susceptibility loci from psoriasis GWAS studies. These gene sets were characterized based upon their expression across 10 cell types present in psoriasis lesions. Susceptibility-associated variation at intergenic (non-coding) loci was evaluated to identify sites of allele-specific transcription factor binding. Results Half of DEGs showed highest expression in skin cells, although the dominant cell type differed between psoriasis-increased DEGs (keratinocytes, 35%) and psoriasis-decreased DEGs (fibroblasts, 33%). In contrast, psoriasis GWAS candidates tended to have highest expression in immune cells (71%), with a significant fraction showing maximal expression in neutrophils (24%, P < 0.001). By identifying candidate cell types for genes near susceptibility loci, we could identify and prioritize SNPs at which susceptibility variants are predicted to influence transcription factor binding. This led to the identification of potentially causal (non-coding) SNPs for which susceptibility variants influence binding of AP-1, NF-κB, IRF1, STAT3 and STAT4. Conclusions These findings underscore the role of innate immunity in psoriasis and highlight neutrophils as a cell type linked with pathogenetic mechanisms. Assignment of candidate cell types to genes emerging from GWAS studies provides a first step towards functional analysis, and we have proposed an approach for generating hypotheses to explain GWAS hits at intergenic loci.http://deepblue.lib.umich.edu/bitstream/2027.42/109537/1/12920_2013_Article_485.pd

Cyclosporin A treatment in severe childhood psoriasis

Though used occasionally, systemic therapies in severe childhood psoriasis have not been systematically investigated. Cyclosporin A (CysA) is effective in adults with severe psoriasis but there are no extensive data regarding the efficacy and safety of its use in childhood psoriasis. In this paper, we describe six children aged between 11 months and 13 years (average: 7.6 years) treated with CysA microemulsion formulation for severe psoriasis, who had been unresponsive to other treatments. The CysA dose ranged from 2 to 4 mg/kg/day, for periods varying from 8 to 105 weeks (mean: 54 weeks). Dose tapering was gradual after lesion improvement and adjusted according to clinical response. Adjuvant therapy with topical steroids, vitamin D3 ointments, coal tar preparations or anthralin was used in all children. Acitretin was used in three patients for short periods. The children were regularly monitored for serum renal and liver function and blood pressure. Improvement of skin lesions was achieved after between 4 and 30 (mean: 12) weeks of treatment, with complete remission in three children. Relapse of lesions occurred in the other children during CysA reduction, but they responded to a dose increase. The treatment was found to be well tolerated and with no significant side-effects. CysA can be used in carefully selected and monitored patients and may represent an alternative tool for severe episodes of psoriasis in children, when other therapies are unsuccessful

A severe case of erythrodermic psoriasis associated with advanced nail and joint manifestations: a case report

<p>Abstract</p> <p>Introduction</p> <p>Erythrodermic psoriasis is a rare generalized clinical presentation of psoriasis in children and adults. Its systemic involvement and a diverse range of clinical findings in the joint and nails are commonly described. A high index of suspicion and an exhaustive differential diagnosis involving other causes of erythroderma should be initially considered.</p> <p>Case presentation</p> <p>We present the case of a 9-year-old native Hispanic girl with severe erythrodermic psoriasis associated with uncommon advanced nail and joint manifestations. Our patient showed an excellent response to methotrexate medication.</p> <p>Conclusion</p> <p>This case shows clinical features not commonly described or reported in severe cases of erythrodermic psoriasis, including severe and rare nail and arthritic findings in a pediatric scenario.</p

Collecting a set of psoriasis family material through a patient organisation; clinical characterisation and presence of additional disorders

BACKGROUND: The aim of the present study was to describe the clinical characteristics of a population of psoriatics sampled from a patient organisation and not from hospitals or out-patient clinics. Furthermore, we wanted to compare siblings with and without psoriasis regarding the occurrence of other diseases. METHODS: At the end of 1991, we initiated a project which aimed to study genetic factors leading to psoriasis. Firstly, we sent questionnaires to all the members of the Swedish Psoriasis Association. We then examined 1,217 individuals (570 with psoriasis) from 310 families, in their homes in the southern part of Sweden. All the available family members were examined clinically and asked about the course of the skin disease and the occurrence of other diseases. The eight hundred members of the proband generation were divided into two groups, with or without psoriasis, and their clinical features were compared. RESULTS: Most individuals in this study population had a mild form of psoriasis. The siblings with psoriasis had joint complaints significantly more frequently than their siblings without the skin disease and those with joint complaints had more widespread skin disease. Among the other studied concomitant diseases (iritis, heart or hypertension disease, endocrine disease, inflammatory bowel disease and neurological disease), we were not able to find any difference. Seventy-seven of 570 persons were found to be in remission (13.5%). Females had a mean onset 2.5 years earlier than males. We were not able to find any correlation between the extent of the skin disease and age at onset. Twice as many persons with joint complaints were found among those with psoriasis than among those without, 28% versus 13%. Almost half (48%) the psoriatics who also had joint complaints had psoriasis lesions on their nails. Endocrine disorders were found in 9% of those without any allele for Cw6, but only in 1% of those who had Cw6. In fact, none of 183 Cw6 carriers had diabetes, as compared to the population prevalence of 3–5% in Sweden. CONCLUSION: With the exception of joint complaints, persons with psoriasis, collected from a patient organisation, did not have an increased frequency of (studied) co-existing diseases

Transfer of MicroRNAs by Embryonic Stem Cell Microvesicles

Microvesicles are plasma membrane-derived vesicles released into the extracellular environment by a variety of cell types. Originally characterized from platelets, microvesicles are a normal constituent of human plasma, where they play an important role in maintaining hematostasis. Microvesicles have been shown to transfer proteins and RNA from cell to cell and they are also believed to play a role in intercellular communication. We characterized the RNA and protein content of embryonic stem cell microvesicles and show that they can be engineered to carry exogenously expressed mRNA and protein such as green fluorescent protein (GFP). We demonstrate that these engineered microvesicles dock and fuse with other embryonic stem cells, transferring their GFP. Additionally, we show that embryonic stem cells microvesicles contain abundant microRNA and that they can transfer a subset of microRNAs to mouse embryonic fibroblasts in vitro. Since microRNAs are short (21–24 nt), naturally occurring RNAs that regulate protein translation, our findings open up the intriguing possibility that stem cells can alter the expression of genes in neighboring cells by transferring microRNAs contained in microvesicles. Embryonic stem cell microvesicles may be useful therapeutic tools for transferring mRNA, microRNAs, protein, and siRNA to cells and may be important mediators of signaling within stem cell niches