Complex temporal decay: a complete analysis

Relaxation dynamics is universal in science and engineering; its study serves to parameterize a system's response and to help identify a microscopic model of the processes involved. When measured data for a phenomenon cannot be fitted using one exponential, the choice of an alternative function to describe the decay becomes nontrivial. Here, we contrast two different, but fundamentally related approaches to fitting nontrivial decay curves; exponential decomposition and the gamma probability density function. Copyright © 2013 John Wiley & Sons, Ltd.     

Extrapontine myelinolysis presenting as acute parkinsonism

Background

Extrapontine myelinolysis presenting with extra pyramidal features suggestive of parkinsonism may be a challenging clinical syndrome. Clinicians should maintain their vigilance while correcting electrolyte imbalances, especially with associated co-morbidity.

Case presentation

A 41-year-old woman presented with acute parkinsonism like features while on a holiday. This followed slow correction of hyponatraemia after repeated vomiting. MRI changes were suggestive of Extrapontine myelinolysis(EPM). This case is at variance with four previous cases reported in the medical literature in that the patient made a full clinical recovery and the MR changes resolved with symptomatic support alone.

Conclusion

Extrapontine myelinolysis could make a complete recovery with symptomatic support alone. During hyponatraemia correction, rapid osmotic shifts of fluid that cause hypernatremia, causes myelinolysis rather than absolute serum sodium level. Even gradual correction of hyponatraemia can produce myelinolysis, especially with pre-existing malnourishment, alcoholism, drug misuse, Addison's disease and immuno-suppression. Pallidial sparing is typical of EPM in MRI scans.     

Mercury‐associated DNA hypomethylation in polar bear brains via the LUminometric Methylation Assay: a sensitive method to study epigenetics in wildlife

In this paper we describe a novel approach that may shed light on the genomic DNA methylation of organisms with non‐resolved genomes. The LUminometric Methylation Assay (LUMA) is permissive for genomic DNA methylation studies of any genome as it relies on the use of methyl‐sensitive and ‐insensitive restriction enzymes followed by polymerase extension via Pyrosequencing technology. Here, LUMA was used to characterize genomic DNA methylation in the lower brain stem region from 47 polar bears subsistence hunted in central East Greenland between 1999 and 2001. In these samples, average genomic DNA methylation was 57.9% ± 6.69 (SD; range was 42.0 to 72.4%). When genomic DNA methylation was related to brain mercury (Hg) exposure levels, an inverse association was seen between these two variables for the entire study population (P for trend = 0.17). After dichotomizing animals by gender and controlling for age, a negative trend was seen amongst male animals (P for trend = 0.07) but no associations were found in female bears. Such sexually dimorphic responses have been found in other toxicological studies. Our results show that genomic DNA methylation can be quantitatively studied in a highly reproducible manner in tissue samples from a wild organism with a non‐resolved genome. As such, LUMA holds great promise as a novel method to explore consequential questions across the ecological sciences that may require an epigenetic understanding.     

First‐derivative synchronous spectrofluorimetric method for estimation of losartan potassium and atorvastatin in their pure forms and in tablets

Losartan potassium (LOS) and atorvastatin (ATR) are used in combination for long‐term treatment of stroke and for treatment of hypertension with high‐level cholesterol. Both drugs were simultaneously determined and validated using a novel, easy, fast, and economical first‐derivative synchronous fluorescence spectroscopic method. Methanol was used as the solvent for both drugs at a Δλ 80 nm and with a scanning rate of 600 nm/min. Peaks were determined as at 288.1 nm and 263.6 nm for LOS and ATR, respectively. The proposed method was validated according to International Conference on Harmonization guidelines and, subsequently, the developed method was applicable to the analysis of the two compounds in their different formulations without interference from each other. Amplitude–concentration plots were rectilinear over the concentration ranges 1.0–10.0 μg/ml and 0.5–5.0 μg/ml for LOS and ATR, respectively. Detection limits were found to be 0.096 μg/ml and 0.030 μg/ml and quantitation limits were 0.291 μg/ml and 0.093 μg/ml for LOS and ATR, respectively. The proposed method was successfully applied to the analysis of both compounds in synthetic mixtures and in laboratory‐prepared tablets. These results were in accordance with the results acquired using the comparison method, high‐performance liquid chromatography.     

Foreign body giant cells and osteoclasts are TRAP positive,have podosome‐belts and both require OC‐STAMP for cell fusion

Macrophages have the ability to fuse and form multinucleated giant cells such as Osteoclast (OCs) and FBGCs. Osteoclast stimulatory transmembrane protein (OC‐STAMP) is an important cell surface protein involved in the formation of OCs. This study sought to determine if OC‐STAMP also regulates formation of FBGCs using expression analysis and subsequent inhibition studies. qPCR and Western blot analysis showed that OC‐STAMP expression is significantly higher in FBGCs compared to control monocytes (P < 0.05). Four days following cell culture, OCs were positive for TRAP and F‐actin ring formation, but FBGCs were not. In contrast, FBGCs were positive for TRAP and showed podosome belts comprised of F‐actin on Day 8. FBGCs were subsequently plated onto dentine, but despite presenting some morphologic features of OCs (OC‐STAMP expression, TRAP reactivity, and podosome belts) they failed to resorb bone. To evaluate a role for OC‐STAMP in FBGCs, we inhibited this cell surface protein with anti‐OC‐STAMP antibody and observed that cell fusion and podosome belt formation was inhibited in both OCs and FBGCs. Our data support the hypothesis that OC‐STAMP is a regulatory molecule for FBGCs; and that they are functionally distinct from OCs, despite similarities in gene expression profile, podosome belt formation, and TRAP expression. J. Cell. Biochem. 114: 1772–1778, 2013. © 2013 Wiley Periodicals, Inc.     

Human dental pulp stem cells expressing transforming growth factor β3 transgene for cartilage-like tissue engineering

Background aimsThe aim of this study was to engineer sizable three-dimensional cartilage-like constructs using stem cells isolated from human dental pulp stem cells (DPSCs).MethodsHuman DPSCs were isolated from teeth extracted for orthodontic treatment and enriched further using immuno-magnetic bead selection for stem cell marker CD146. Chondrogenic lineage differentiation of DPSCs induced using recombinant transforming growth factor β3 (TGFβ3) was verified by pellet culture. Because the use of recombinant proteins is associated with rapid degradation and difficult in vivo administration, we constructed the recombinant adeno-associated viral vector encoding human TGFβ3 and determined the best multiplicity of infection for DPSCs. Transduced DPSCs were seeded on poly-l-lactic acid/polyethylene glycol (PLLA/PEG) electrospun fiber scaffolds demonstrating proper attachment, proliferation and viability as shown by scanning electron microscopy micrographs and CCK-8 cell counting kit. Scaffolds seeded with DPSCs were implanted in the back of nude mice.ResultsTransduced DPSCs highly expressed human TGFβ3 for up to 48 days and expressed chondrogenic markers collagen IIa1, Sox9 and aggrecan, as verified by immunohistochemistry and messenger RNA (mRNA). Immunohistochemistry for TGFβ3/DPSC constructs (n = 5/group) showed cartilage-like matrix formation with glycosaminoglycans. In vivo constructs with TGFβ3/DPSCs showed higher collagen type II and Sox9 mRNA expression relative to non-transduced DPSC constructs (n = 5/group). Western blot analysis confirmed this expression pattern on the protein level (n = 3/group).ConclusionsImmuno-selected DPSCs can be successfully differentiated toward chondrogenic lineage, while expressing the chondrogenic inducing factor. Seeded on PLLA/PEG electrospun scaffold, human DPSCs formed three-dimensional cartilage constructs that could prove useful in future treatment of cartilage defects.     

A targeted lipidomics approach to the study of eicosanoid release in synovial joints

Introduction  

Articular tissues are capable of producing a range of eicosanoid mediators, each of which has individual biological effects and may be affected by anti-inflammatory treatment. We set out to develop and evaluate a high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) approach for the simultaneous analysis of multiple eicosanoid lipid mediators in equine synovial fluid (SF), and to illustrate its use for investigation of the in vivo effects of non-steroidal anti-inflammatory drug (NSAID) treatment.     

诱导型一氧化氮合酶基因多态性与2型糖尿病关系研究

目的：观察诱导型一氧化氮合酶（iNOs）基因Ser608Leu位点基因多态性与2型糖尿病的相关性。方法：采用测序法测定261例2型糖尿病患者和128例正常对照者iNOS基因Ser608Leu位点基因多态性。结果：两组间iNOS基因Ser608Leu位点基因型及等位基因频率构成存在差异。结论：iNOS基因Ser608Leu位点多态性与2型糖尿病有关。     

重组腺病毒Ad-HGF体外感染成纤维细胞后转染效率及表达的检测

押检测携带人肝细胞生长因子基因的重组腺病毒Ad-HGF在体外对成纤维细胞的感染效率以及感染细胞对目的蛋白的表达。以不同感染复数(m.o.i.)(25,50,100,200)的Ad-GFP感染NIH3T3细胞,48h时用流式细胞仪检测转染效率;以50m.o.i.感染NIH3T3细胞后48h,用ELISA和Western印迹杂交法分别检测感染上清中HGF的表达。分别以50m.o.i.的Ad-GFP和Ad-HGF感染原代培养人瘢痕成纤维细胞,以检测重组腺病毒对原代培养人瘢痕成纤维细胞的转染效率和其对HGF的表达。结果表明,当m.o.i.为50时,重组腺病毒对NIH3T3细胞的转染效率已达95%以上;HGF的表达量可达每2×106细胞249ng;并可检测到HGF蛋白的一特异杂交带。以50m.o.i.的Ad-GFP感染原代培养人瘢痕成纤维细胞,72h时GFP表达达高峰,此时转染效率可高达36.75%。Ad-HGF感染原代培养人瘢痕成纤维细胞后HGF的表达在72h时达高峰,表达量可达每3.3×105细胞66ng。初步认为重组腺病毒可有效地介导HGF基因转染正常或瘢痕成纤维细胞,且感染细胞可有效表达目的蛋白。