Transcranial direct current stimulation over somatosensory cortex decreases experimentally induced acute pain perception

OBJECTIVE: Multiple cortical areas including the primary somatosensory cortex are known to be involved in nociception. The aim of this study was to investigate the effect of transcranial direct current stimulation (tDCS) that modulates the cortical excitability painlessly and noninvasively, over somatosensory cortex on acute pain perception induced with a Tm:YAG laser. METHODS: Subjective pain rating scores and amplitude changes of the N1, N2, and P2 components of laser-evoked potentials of 10 healthy participants were analyzed before and after anodal, cathodal, and sham tDCS. RESULTS: Our results demonstrate that cathodal tDCS significantly diminished pain perception and the amplitude of the N2 component when the contralateral hand to the side of tDCS was laser-stimulated, whereas anodal and sham stimulation conditions had no significant effect. DISCUSSION: Our study highlights the antinociceptive effect of this technique and may contribute to the understanding of the mechanisms underlying pain relief. The pharmacologic prolongation of the excitability-diminishing after-effects would render the method applicable to different patient populations with chronic pain.     

Epidermal growth factor receptor (EGFR) high gene copy number and activating mutations in lung adenocarcinomas are not consistently accompanied by positivity for EGFR protein by standard immunohistochemistry

The purpose of this study was to investigate whether detectable protein biomarker overexpression is a prerequisite for the presence of increased gene copy number or activating mutations and responsiveness to the epidermal growth factor receptor (EGFR) inhibitors gefitinib and erlotinib in patients with lung adenocarcinomas. EGFR status was prospectively analyzed in tumor biopsy samples by three methods: protein expression (n = 117) by standardized immunohistochemistry (IHC), gene copy number (n = 97) by fluorescent in situ hybridization (FISH), and mutation analysis by sequencing (n = 126). Fifty-nine percent of the samples were positive by IHC, 40% were positive by FISH, and 13.5% contained activating kinase domain mutations. Thirty-four percent of the FISH-positive and 27% of the mutant samples were also IHC-negative. All EGFR mutant patients had major clinical responses (five complete response and five partial response) to gefitinib or erlotinib treatment, although three of these tumors were IHC-negative and four were FISH-negative. In a retrospective analysis of samples from nine patients with excellent therapeutic responses (three complete response, five partial response, one stable disease) to erlotinib or gefitinib, mutations were identified in eight cases, but IHC was negative in four of these tumors. These results indicate that molecular diagnostic methods appear to be most important for the identification of lung adenocarcinoma patients who may benefit from EGFR inhibitor treatments.     

Labeling of pancreatic islets with iron oxide nanoparticles for in vivo detection with magnetic resonance

In vitro labeling of pancreatic islets with iron nanoparticles enables their direct posttransplant visualization by magnetic resonance; however, there is still a discrepancy in the fate of iron nanoparticles. This study was performed to detail the labeling process, consequently to improve the labeling efficacy and to confirm safety for islet cells. The islets were visible on T2*-weighted magnetic resonance images as hypointense spots immediately after 1-hr cultivation. Although at this time already the sufficient superparamagnetic effect was achieved, most of the particles were deposed in islet macrophages and only later were they found in endosomes of endocrine islet cells. The iron content depended on length of culture period. The labeled islets showed an intact ultrastructure, responded normally to glucose stimulation in vitro, and were able to treat experimental diabetes. For purpose of subsequent magnetic resonance imaging, a 24-hr culture with ferucarbotran leads to sufficient labeling with no apparent adverse effect on beta cell morphology or function.     

Erlotinib directly inhibits HER2 kinase activation and downstream signaling events in intact cells lacking epidermal growth factor receptor expression

Erlotinib (Tarceva), is an orally available, reversible inhibitor of epidermal growth factor receptor (EGFR; HER1) that exhibits inhibitory activity on purified HER2 kinase at much higher concentrations. Despite the minimal activity on purified protein in vitro, in vivo studies show that erlotinib inhibits the growth of HER2-driven systems effectively. Several hypotheses have been put forward to explain this discrepancy. In particular, it has been suggested that erlotinib might indirectly suppress the activity of HER2 by blocking the ability of EGFR to transactivate it when the two receptors are part of a heterodimer complex. However, an alternative possibility that has not been adequately addressed is whether the direct inhibitory action of erlotinib on the HER2 kinase might account for the observed biological responses. To distinguish between a direct effect of erlotinib on HER2 kinase in intact cells or an indirect effect of erlotinib on HER2 activity that is mediated through EGFR, we generated cell lines that express either EGFR-H2 chimeric receptor or HER2 and HER3 receptors in an EGFR-negative background. We show that dose-dependent inhibition of HER2 was achieved at the receptor level, on downstream signaling molecules, and more importantly was also translated into inhibition of cell growth. Our findings imply that the inhibitory effect of erlotinib in HER2-expressing cells may in part be mediated through direct interaction with HER2 rather than indirectly through a process that requires the presence of EGFR.     

The relationship between the vitamin K cycle inhibition and the plasma anticoagulant response at steady-state S-warfarin conditions in the rat.

The relationship between the inhibition of the vitamin K cycle and the inhibition of the vitamin K-dependent clotting factor synthesis was studied in the rat under a controlled rate of S-warfarin administration. Steady state of drug disposition was achieved from beyond day 2 and stable anticoagulation was achieved from beyond days 3 to 4. Doses up to 0.5 micrograms/kg/h were without effect, whereas 3 micrograms/kg/h reduced prothrombin complex activity to about 10%. Factor II and factor VII activity were equally suppressed as prothrombin complex activity. The concentration-effect relationship for steady-state S-warfarin plasma concentration and the inhibition of clotting factor synthesis revealed a steep sigmoidal response relationship (IC50 = 0.21 +/- 0.01 micrograms/ml, Hill slope = 2.07 +/- 0.3). Contrary to this, the target enzyme vitamin K1 2,3-epoxide reductase showed a dose-dependent response for the entire dose range. The sigmoidal effect relationship for plasma S-warfarin and enzyme inhibition showed a slope of 0.81 +/- 0.07 with IC50 = 16 +/- 1 ng/ml. The results demonstrate a reserve capacity for the coumarin-sensitive reductase; at least 70% of the hepatic vitamin K1 2,3-epoxide reductase activity has to be eliminated before the vitamin K-dependent carboxylation of the clotting factors objectively becomes compromised. In the study, the microsomal warfarin binding sites were compared with the vitamin K1 2,3-epoxide reductase activity, and a strict 1 to 1 relationship was found supporting the relationship between both.(ABSTRACT TRUNCATED AT 250 WORDS)     

School Wellness Committees Are Associated With Lower Body Mass Index Z‐Scores and Improved Dietary Intakes in US Children: The Healthy Communities Study

BACKGROUND

Our objective was to examine the association between school wellness committees and implementation of nutrition wellness policies and children's weight status and obesity‐related dietary outcomes.

METHODS

A cross‐sectional study was conducted of 4790 children aged 4‐15 years recruited from 130 communities in the Healthy Communities Study. Multilevel statistical models assessed associations between school wellness policies and anthropometric (body mass index z‐score [BMIz]) and nutrition measures, adjusting for child and community‐level covariates.

RESULTS

Children had lower BMI z‐scores (?0.11, 95% confidence interval [CI]: ?0.19, ?0.03) and ate breakfast more frequently (0.14 days/week, 95% CI: 0.02‐0.25) if attending a school with a wellness committee that met once or more in the past year compared to attending a school with a wellness committee that did not meet/did not exist. Children had lower added sugar (p < .0001), lower energy‐dense foods (p = .0004), lower sugar intake from sugar‐sweetened beverages (p = .0002), and lower dairy consumption (p = .001) if attending a school with similar or stronger implementation of the nutrition components of the school wellness policies compared to other schools in the district.

CONCLUSIONS

A more active wellness committee was associated with lower BMI z‐scores in US schoolchildren. Active school engagement in wellness policy implementation appears to play a positive role in efforts to reduce childhood obesity.

     

Altered tension cost in (TG(mREN-2)27) rats overexpressing the mouse renin gene

The present study aimed to characterize cardiac hypertrophy induced by activation of the renin–angiotensin system in terms of functional alterations on the level of the contractile proteins, employing transgenic rats harboring the mouse renin gene (TGR(mREN2)27). Ca²⁺-dependent tension and myosin ATPase activity were measured in skinned fiber preparations obtained from TGR(mREN2)27 and from age-matched Sprague–Dawley rats (SPDR). Western blots for troponin I (TnI) and troponin T (TnT) were performed and the phosphorylation status of TnI were evaluated in myocardial preparations. TnT and myosin heavy chain (MHC) isoforms were analyzed by RT-PCR. The pCa/tension relationship was shifted to the right in TGR(mREN2)27 compared to SPDR as indicated by increased Ca²⁺-concentrations required for half maximal activation of tension (SPDR 5.80, 95% confidence limits 5.77–5.82 vs. TGR(mREN2)27 5.69, 95% confidence limits 5.67–5.72, pCa units), while maximal developed tension was unaltered. Even more pronounced was the shift in the relationship between pCa and myosin–ATPase (SPDR 6.01, 95% confidence limits 5.99–6.03 vs. TGR(mREN2)27 5.77, 95% confidence limits 5.73–5.79, pCa units). The maximal myosin–ATPase activity was reduced in TGR(mREN2)27 compared to SPDR, respectively (211.0 ± 28.77 μmol ADP/s vs. 271.6 ± 43.66 μmol ADP/s, P < 0.05). Tension cost (ATPase activity/tension) was significantly reduced in TGR(mREN2)27. The β-MHC expression was significantly increased in TGR(mREN2)27. There was no isoform shift for TnT (protein and mRNA), as well as TnI, and no alteration of the phosphorylation of TnI in TGR(mREN2)27 compared to SPRD. The present study demonstrates that cardiac hypertrophy, induced by an activation of the renin–angiotensin system, leads to adapting alterations on the level of the contractile filaments, which reduce tension cost.     

Interference of contaminated sediment extracts and environmental pollutants with retinoid signaling

Retinoids are known to regulate important processes such as differentiation, development, and embryogenesis. Some effects, such as malformations in frogs or changes in metabolism of birds, could be related to disruption of the retinoid signaling pathway by exposure to organic contaminants. A new reporter gene assay has been established for evaluation of the modulation of retinoid signaling by individual chemicals or environmental samples. The bioassay is based on the pluripotent embryonic carcinoma cell line P19 stably transfected with the firefly luciferase gene under the control of a retinoic acid-responsive element (clone P19/ A15). The cell line was used to characterize the effects of individual chemicals and sediments extracts on retinoid signaling pathways. The extracts of sediments from the River Kymi, Finland, which contained polychlorinated dioxins and furans and polycyclic aromatic hydrocarbons (PAHs), significantly increased the potency of all-trans retinoic acid (ATRA), while no effect was observed with the extract of the sediment from reference locality. Considerable part of the effect was caused by the labile fraction of the sediment extracts. Also, several individual PAHs potentiated the effect of ATRA; on the other hand, 2,3,7,8-tetrachlorodibenzo-p-dioxin and several phthalates showed slightly inhibiting effect. These results suggest that PAHs could be able to modulate the retinoid signaling pathway and that they could be responsible for a part of the proretinoid activity observed in the sediment extracts. However, the effects of PAHs on the retinoic acid signaling pathways do not seem to be mediated directly by crosstalk with aryl hydrocarbon receptor.