Sphingosine 1-Phosphate Mediates Hyperalgesia via a Neutrophil-Dependent Mechanism

Novel classes of pain-relieving molecules are needed to fill the void between non-steroidal anti-inflammatory agents and narcotics. We have recently shown that intraplantar administration of sphingosine 1-phosphate (S1P) in rats causes peripheral sensitization and hyperalgesia through the S1P₁ receptor subtype (S1PR₁): the mechanism(s) involved are largely unknown and were thus explored in the present study. Intraplantar injection of carrageenan in rats led to a time-dependent development of thermal hyperalgesia that was associated with pronounced edema and infiltration of neutrophils in paw tissues. Inhibition of 1) S1P formation with SK-I, a sphingosine kinase inhibitor, 2) S1P bioavailability with the S1P blocking antibody Sphingomab, LT1002 (but not its negative control, LT1017) or 3) S1P actions through S1PR₁ with the selective S1PR₁ antagonist, W146 (but not its inactive enantiomer, W140) blocked thermal hyperalgesia and infiltration of neutrophils. Taken together, these findings identify S1P as an important contributor to inflammatory pain acting through S1PR₁ to elicit hyperalgesia in a neutrophil-dependant manner. In addition and in further support, we demonstrate that the development of thermal hyperalgesia following intraplantar injection of S1P or SEW2871 (an S1PR₁ agonist) was also associated with neutrophilic infiltration in paw tissues as these events were attenuated by fucoidan, an inhibitor of neutrophilic infiltration. Importantly, FTY720, an FDA-approved S1P receptor modulator known to block S1P-S1PR₁ signaling, attenuated carrageenan-induced thermal hyperalgesia and associated neutrophil infiltration. Targeting the S1P/S1PR₁ axis opens a therapeutic strategy for the development of novel non-narcotic anti-hyperalgesic agents.     

Involvement of the Reck tumor suppressor protein in maternal and embryonic vascular remodeling in mice

Background

The accessibility of the developing zebrafish pharyngeal dentition makes it an advantageous system in which to study many aspects of tooth development from early initiation to late morphogenesis. In mammals, hedgehog signaling is known to be essential for multiple stages of odontogenesis; however, potential roles for the pathway during initiation of tooth development or in later morphogenesis are incompletely understood.

Results

We have identified mRNA expression of the hedgehog ligands shha and the receptors ptc1 and ptc2 during zebrafish pharyngeal tooth development. We looked for, but did not detect, tooth germ expression of the other known zebrafish hedgehog ligands shhb, dhh, ihha, or ihhb, suggesting that as in mammals, only Shh participates in zebrafish tooth development. Supporting this idea, we found that morphological and gene expression evidence of tooth initiation is eliminated in shha mutant embryos, and that morpholino antisense oligonucleotide knockdown of shha, but not shhb, function prevents mature tooth formation. Hedgehog pathway inhibition with the antagonist compound cyclopamine affected tooth formation at each stage in which we applied it: arresting development at early stages and disrupting mature tooth morphology when applied later. These results suggest that hedgehog signaling is required continuously during odontogenesis. In contrast, over-expression of shha had no effect on the developing dentition, possibly because shha is normally extensively expressed in the zebrafish pharyngeal region.

Conclusion

We have identified previously unknown requirements for hedgehog signaling for early tooth initiation and later morphogenesis. The similarity of our results with data from mouse and other vertebrates suggests that despite gene duplication and changes in the location of where teeth form, the roles of hedgehog signaling in tooth development have been largely conserved during evolution.     

Rationale and design of EXPLORE: a randomized, prospective, multicenter trial investigating the impact of recanalization of a chronic total occlusion on left ventricular function in patients after primary percutaneous coronary intervention for acute ST-elevation myocardial infarction

Background

Hypothyroidism is a prevalent endocrine condition. Individuals with this disease are commonly managed through supplementation with synthetic thyroid hormone, with the aim of alleviating symptoms and restoring normal thyroid stimulating hormone levels. Generally this management strategy is effective and well tolerated. However, there is research to suggest that a significant proportion of hypothyroid sufferers are being inadequately managed. Furthermore, hypothyroid patients are more likely to have a decreased sense of well-being and more commonly experience constitutional and neuropsychiatric complaints, even with pharmacological intervention. The current management of hypothyroidism follows a biomedical model. Little consideration has been given to a biopsychosocial approach to this condition. Within the chiropractic profession there is growing support for the use of a biopsychosocial-based intervention called Neuro-Emotional Technique (NET) for this population.

Methods/Design

A placebo-controlled, single-blinded, randomised clinical pilot-trial has been designed to assess the influence of Neuro-Emotional Technique on a population with primary overt hypothyroidism. A sample of 102 adults (≥18 years) who meet the inclusion criteria will be randomised to either a treatment group or a placebo group. Each group will receive ten treatments (NET or placebo) over a six week period, and will be monitored for six months. The primary outcome will involve the measurement of depression using the Depression, Anxiety and Stress Scale (DASS). The secondary outcome measures to be used are; serum thyroid stimulating hormone, serum free-thyroxine, serum free-triiodothyronine, serum thyroid peroxidase auto-antibodies, serum thyroglobulin auto-antibodies as well as the measurement of functional health and well-being using the Short-Form-36 Version 2. The emotional states of anxiety and stress will be measured using the DASS. Self-measurement of basal heart rate and basal temperature will also be included among the secondary outcome measures. The primary and secondary measures will be obtained at commencement, six weeks and six months. Measures of basal heart rate and basal temperature will be obtained daily for the six month trial period, with recording to commence one week prior to the intervention.

Discussion

The study will provide information on the influence of NET when added to existing management regimens in individuals with primary overt hypothyroidism.

Trial Registration

ANZCTR Number: 12607000040460     

Characterization of chaotic dynamics in the human menstrual cycle

Background  

The human menstrual cycle is known to exhibit a significant amount of unexplained variability. This variation is typically dismissed as random fluctuations in an otherwise periodic and predictable system. Given the many delayed nonlinear feedbacks in the multiple levels of the reproductive endocrine system, however, the menstrual cycle can properly be construed as the output of a nonlinear dynamical system, and such a system has the possibility of being in a chaotic trajectory. We hypothesize that this is in fact the case and that it accounts for the observed variability.     

Calcium and pH-induced structural changes in skinned muscle fibers: prevention by N-ethylmaleimide.

Optical diffractometry was used to investigate structural changes in contractile proteins from chemically skinned muscle fibers. The intensity of the first order diffraction line decreased in response to calcium and alkaline pH. Fibers pre-treated with sulfhydryl blocking agents did not exhibit the calcium- or pH- induced intensity decreases. We suggest that the decreases in intensity result from structural changes in the thick filament. Optical diffractometry may be a useful technique for the investigation of conformational changes in myosin.     

酿酒酵母孢子壁结构及其合成相关基因研究进展

细胞壁是酵母细胞区别于哺乳动物细胞的重要特征结构。酵母细胞壁的结构组成、合成、再生等与酵母自身繁殖及环境胁迫压力密切相关。目前,酵母孢子壁的形成机理、调控过程机制及孢子壁合成相关基因的功能尚未研究清楚。本文以酿酒酵母为例,简要描述酵母孢子壁的形成过程,重点阐述孢子壁甘露糖层、葡聚糖层、壳聚糖层和二酪氨酸层的结构组成及其合成相关基因的国内外研究进展,以期为抗真菌药物的新靶点研究提供参考。     

Identification of DNA-binding proteins using support vector machines and evolutionary profiles

Background  

Identification of DNA-binding proteins is one of the major challenges in the field of genome annotation, as these proteins play a crucial role in gene-regulation. In this paper, we developed various SVM modules for predicting DNA-binding domains and proteins. All models were trained and tested on multiple datasets of non-redundant proteins.     

Studies of genotoxicity and mutagenicity of nitroimidazoles: demystifying this critical relationship with the nitro group

Nitroimidazoles exhibit high microbicidal activity, but mutagenic, genotoxic and cytotoxic properties have been attributed to the presence of the nitro group. However, we synthesised nitroimidazoles with activity against the trypomastigotes of Trypanosoma cruzi, but that were not genotoxic. Herein, nitroimidazoles (11-19) bearing different substituent groups were investigated for their potential induction of genotoxicity (comet assay) and mutagenicity (Salmonella/Microsome assay) and the correlations of these effects with their trypanocidal effect and with megazol were investigated. The compounds were designed to analyse the role played by the position of the nitro group in the imidazole nucleus (C-4 or C-5) and the presence of oxidisable groups at N-1 as an anion receptor group and the role of a methyl group at C-2. Nitroimidazoles bearing NO2 at C-4 and CH3 at C-2 were not genotoxic compared to those bearing NO₂ at C-5. However, when there was a CH3 at C-2, the position of the NO2 group had no influence on the genotoxic activity. Fluorinated compounds exhibited higher genotoxicity regardless of the presence of CH3 at C-2 or NO2 at C-4 or C-5. However, in compounds 11 (2-CH3; 4-NO2; N-CH2OHCH2Cl) and 12 (2-CH3; 4-NO2; N-CH2OHCH2F), the fluorine atom had no influence on genotoxicity. This study contributes to the future search for new and safer prototypes and provide.     

Optimizing harvest of corn stover fractions based on overall sugar yields following ammonia fiber expansion pretreatment and enzymatic hydrolysis

Background  

Corn stover composition changes considerably throughout the growing season and also varies between the various fractions of the plant. These differences can impact optimal pretreatment conditions, enzymatic digestibility and maximum achievable sugar yields in the process of converting lignocellulosics to ethanol. The goal of this project was to determine which combination of corn stover fractions provides the most benefit to the biorefinery in terms of sugar yields and to determine the preferential order in which fractions should be harvested. Ammonia fiber expansion (AFEX) pretreatment, followed by enzymatic hydrolysis, was performed on early and late harvest corn stover fractions (stem, leaf, husk and cob). Sugar yields were used to optimize scenarios for the selective harvest of corn stover assuming 70% or 30% collection of the total available stover.