The Influence of Oral Magnesium Sulfate on Skin Microvasculature Blood Flow in Diabetic Rats

Microvascular disease is a major feature of type1 diabetes and results from long-standing structural and functional changes especially in the skin microvasculature. Magnesium (Mg) deficiency has recently been proposed as a novel factor implicated in the pathogenesis of diabetes complications such as vascular disturbance, but its mechanism of action is not completely elucidated. The present study was designed to determine whether chronic magnesium sulfate administration could control streptozocin-induced diabetes and improve endothelium-dependent and endothelium-independent dilatation, and identify its probable mechanism in the skin microvasculature of diabetic rats. Fifty male Wistar rats (220?±?10 g) were divided into two diabetic and one control groups. One subgroup of diabetic received magnesium sulfate (10 g/l) in their drinking water, while two other groups had only tap water. Laser Doppler flow meter with iontophoresis was used to measure the relative changes in skin blood flow. We used acetylcholine (Ach), sodium nitroprusside (SNP), and N ^w-nitro-l-arginine (LNNA; NO synthase inhibitor) with magnesium sulfate (0.1 M) in control and experimental animal by microsyringe pump microinjection. SNP- and Ach-induced cutaneous perfusion increased significantly by Mg treatment in the diabetic groups, and local microinjection of magnesium sulfate (0.1 M) increased cutaneous blood flow in all groups (p?<?0.01). However, the administration of LNNA prior to magnesium sulfate attenuated (p?<?0.05) but not abolished the increase in cutaneous blood flow in diabetic and normal rats. From the results of this study, it may be concluded that Mg could improve skin microvasculature of diabetic rats with potentiation of nitric oxide pathway.     

MicroRNAs in the shoot apical meristem of soybean

Plant microRNAs (miRNAs) play crucial regulatory roles in various developmental processes. In this study, we characterize the miRNA profile of the shoot apical meristem (SAM) of an important legume crop, soybean, by integrating high-throughput sequencing data with miRNA microarray analysis. A total of 8423 non-redundant sRNAs were obtained from two libraries derived from micro-dissected SAM or mature leaf tissue. Sequence analysis allowed the identification of 32 conserved miRNA families as well as 8 putative novel miRNAs. Subsequent miRNA profiling with microarrays verified the expression of the majority of these conserved and novel miRNAs. It is noteworthy that several miRNAs* were expressed at a level similar to or higher than their corresponding mature miRNAs in SAM or mature leaf, suggesting a possible biological function for the star species. In situ hybridization analysis revealed a distinct spatial localization pattern for a conserved miRNA, miR166, and its star speciessuggesting that they serve different roles in regulating leaf development. Furthermore, localization studies showed that a novel soybean miRNA, miR4422a, was nuclear-localized. This study also indicated a novel expression pattern of miR390 in soybean. Our approach identified potential key regulators and provided vital spatial information towards understanding the regulatory circuits in the SAM of soybean during shoot development.     

Modulation of anticonvulsant effects of cannabinoid compounds by GABA-A receptor agonist in acute pentylenetetrazole model of seizure in rat

Cannabinoid system plays an important role in controlling neuronal excitability and brain function. On the other hand, modulation of gamma-aminobutyric acid (GABA) transmission is one of the initial strategies for the treatment of seizure. The aim of the present study was to evaluate possible interaction between cannabinoidergic and GABAergic systems in pentylenetetrazole (PTZ)-induced acute seizure in rat. Drugs were administered by intracerebroventricular (i.c.v.) administration 20 min before a single intraperitoneal (i.p.) injection of PTZ and the latency to the first generalized tonic-clonic seizure was measured. Both the cannabinoid receptor agonist WIN55212-2 (10, 30, 50 and 100 μg/rat) and the GABA-A receptor agonist isoguvacine (IGN; 10, 30 and 50 μg/rat) significantly increased the latency of seizure occurrence. Moreover, the fatty acid amide hydrolase inhibitor URB597 showed no anticonvulsive effect while the monoacyl glycerol lipase (MAGL) inhibitor URB602 (10, 50 and 100 μg/rat) protected rats against PTZ-induced seizure. Moreover, co-administration of IGN and cannabinoid compounds attenuated the anticonvulsant action of both WIN55212-2 and IGN in this model of seizure. Our data suggests that exogenous cannabinoid WIN55212-2 and MAGL inhibitor URB602 imply their antiseizure action in part through common brain receptorial system. Moreover, the antagonistic interaction of cannabinoids and IGN in protection against PTZ-induced seizure could suggest the involvement of GABAergic system in their anticonvulsant action.     

Phasor analysis of multiphoton spectral images distinguishes autofluorescence components of in vivo human skin

Skin contains many autofluorescent components that can be studied using spectral imaging. We employed a spectral phasor method to analyse two photon excited autofluorescence and second harmonic generation images of in vivo human skin. This method allows segmentation of images based on spectral features. Various structures in the skin could be distinguished, including Stratum Corneum, epidermal cells and dermis. The spectral phasor analysis allowed investigation of their fluorescence composition and identification of signals from NADH, keratin, FAD, melanin, collagen and elastin. Interestingly, two populations of epidermal cells could be distinguished with different melanin content. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Short-term effect of weight loss through restrictive bariatric surgery on serum levels of vaspin in morbidly obese subjects

The aims of this study were to evaluate the short-term effects of laparoscopic restrictive bariatric surgery (LRBS) on plasma levels of vaspin and the potential associations of changes in vaspin levels with changes in anthropometric indices, insulin-resistance and dietary intake. Thirty, severely obese subjects (21 female; mean age, 32.5 years) with a mean body mass index (BMI) of 44.1 ± 4.9 kg/m(2) underwent LRBS. Measurements of anthropometric indices, dietary intakes, physical activity and plasma vaspin concentrations were performed prior to, and six weeks after LRBS. Insulin-sensitivity was estimated using the homeostasis model assessment of insulin-resistance (HOMA-IR). Six weeks after LRBS, BMI decreased to a mean of 38.4 ± 4.9 kg/m(2). Significant reductions were also observed in waist circumference (WC), daily intakes of calorie, fat and protein, and plasma concentrations of triglyceride. No significant change was observed in fasting levels of insulin, blood sugar or HOMA-IR. Vaspin decreased significantly (0.26 ± 0.17 vs 0.36 ± 0.20, p=0.048) following surgery. While the percentage change of vaspin was not correlated with percent changes in anthropometric indices and HOMA-IR, it correlated positively with the percentage change in intake of calories, fat and protein: this correlation remained significant even after adjustment for sex and changes in WC and HOMA-IR. Our study suggests that LRBS decreases the serum vaspin concentrations in parallel with the restriction of dietary intake. Furthermore, decreased levels of vaspin early after LRBS seem more likely to result from decreased dietary intake rather than weight-loss-induced insulin sensitivity improvement.     

Palmitate-activated macrophages confer insulin resistance to muscle cells by a mechanism involving protein kinase C θ and ε

Background

Macrophage-derived factors contribute to whole-body insulin resistance, partly by impinging on metabolically active tissues. As proof of principle for this interaction, conditioned medium from macrophages treated with palmitate (CM-PA) reduces insulin action and glucose uptake in muscle cells. However, the mechanism whereby CM-PA confers this negative response onto muscle cells remains unknown.

Methodology/Principal Findings

L6-GLUT4myc myoblasts were exposed for 24 h to palmitate-free conditioned medium from RAW 264.7 macrophages pre-treated with 0.5 mM palmitate for 6 h. This palmitate-free CM-PA, containing selective cytokines and chemokines, inhibited myoblast insulin-stimulated insulin receptor substrate 1 (IRS1) tyrosine phosphorylation, AS160 phosphorylation, GLUT4 translocation and glucose uptake. These effects were accompanied by a rise in c-Jun N-terminal kinase (JNK) activation, degradation of Inhibitor of κBα (IκBα), and elevated expression of proinflammatory cytokines in myoblasts. Notably, CM-PA caused IRS1 phosphorylation on Ser1101, and phosphorylation of novel PKCθ and ε. Co-incubation of myoblasts with CM-PA and the novel and conventional PKC inhibitor Gö6983 (but not with the conventional PKC inhibitor Gö6976) prevented PKCθ and ε activation, JNK phosphorylation, restored IκBα mass and reduced proinflammatory cytokine production. Gö6983 also restored insulin signalling and glucose uptake in myoblasts. Moreover, co-silencing both novel PKC θ and ε isoforms in myoblasts by RNA interference, but not their individual silencing, prevented the inflammatory response and restored insulin sensitivity to CM-PA-treated myoblasts.

Conclusions/Clinical Significance

The results suggest that the block in muscle insulin action caused by CM-PA is mediated by novel PKCθ and PKCε. This study re-establishes the participation of macrophages as a relay in the action of fatty acids on muscle cells, and further identifies PKCθ and PKCε as key elements in the inflammatory and insulin resistance responses of muscle cells to macrophage products. Furthermore, it portrays these PKC isoforms as potential targets for the treatment of fatty acid-induced, inflammation-linked insulin resistance.     

Association of cyclin-dependent kinase inhibitor 2A/B with increased risk of developing breast cancer

There is a growing body of data reporting the association of genetic alterations in chromosome 9P21 with the risk of developing cancer. In the current study, we studied the association of a genetic variant in CDKN2A/B, rs1333049, with the risk of developing breast cancer. A total of 339 participants with and without breast cancer entered to the study. Genotyping was done by the TaqMan real-time polymerase chain reaction (RT-PCR) method and gene expression analysis was ran by RT-PCR. Our data showed that the minor allele homozygote in the total population was 10%, whereas for heterozygote was 38%. The dominant genetic model demonstrated that individuals with breast cancer had advanced TNM classification. Moreover, the logistic regression revealed that individuals who had CC/CG genotypes might have an enhanced risk of developing breast cancer when compared to the holders of GG genotype (e.g., OR = 2.8; 95% CI,1.4–5.4; p = .001), after regulated for confounders; age and body mass index. Furthermore, our analysis showed that the CDKN2A/B gene was downregulated in patients (p < .001). We showed a meaningful relationship of CDKN2A/B with the risk of breast cancer, cancer, showing the importance of studies in great sample size and several centers for studying the value of the marker as a risk classification in the management of patients with breast cancer.