Time-Dependent Effects of Stress on Cocaine Conditioned Place Preference Using a Rat Model of Posttraumatic Stress Disorder

Posttraumatic Stress Disorder (PTSD) affects approximately 8% of the entire population within their lifetimes. A startling trend of co-occurring PTSD and cocaine use has surfaced among humans who express these disorders. The present study employed the rat model of PTSD, Single Prolonged Stress, to examine the effects of stress on the rewarding properties of cocaine. Place conditioning was used to specifically evaluate differences between animals that had undergone a post-stress delay of conditioning in comparison to animals that were not delayed. This delay before conditioning, or incubation period, is a time spent undisturbed in the home cage for 10-days post-stress and has been implicated as the phase in which many of the physiological, neurochemical and behavioral changes observed in humans who have experienced stress take place. Although cocaine conditioned place preference was observed, no significant differences were detected between animals that were not stressed, stressed but not incubated, or stressed and then incubated. These results suggest that it is possible that the changes that are understood to take place within this incubation period did not directly influence cocaine reward, or that they did not take place. Future work should focus on examining different drugs, in addition to including additional testing intervals, and varying drug dose

Gold nanoparticle and mean inactivation dose of human intestinal colon cancer HT-29 cells

Background: Mean inactivation dose is a useful radiobiological parameter for the comparison of human cell survival curves. Objectives: Given the importance and accuracy of these parameters, in the present study, the radio sensitivity enhancement of colon cancer (HT-29) cells in the presence of gold nanoparticles (GNPs) were studied using the mean inactivation dose (MID). Materials and Methods: Naked-GNPs with 50 nm diameters were incubated with HT-29 cells. The cytotoxicity and uptake of these particles on HT-29 cells were assessed. After determining the optimum GNPs concentration, the cells were incubated with gold nanoparticle for 24 hours. The change in the MID value as well as the radio sensitization enhancement under irradiation with 9 MV X-ray beams in the presence of GNPs were evaluated by multiple (3-(4, 5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium)MTS assay. Results: Cell survival in the presence of GNPs was more than 90% and the maximum uptake of GNPs was observed at 60 μM of gold nanoparticles. In contrast, in the presence of GNPs combined with radiation, cell survival and MID value significantly decreased, so that the radio sensitization enhancement was 1.4. Conclusions: Due to the significant reduction in the mean inactivation dose of colon cancer cells in the presence of gold nanoparticles, it seems that GNPs are suitable options to achieve a new approach in order to improve radiotherapy efficiency without increasing the prescribed radiation dose

Bone morphogenetic protein 7 sensitizes O6-methylguanine methyltransferase expressing-glioblastoma stem cells to clinically relevant dose of temozolomide.

BackgroundTemozolomide (TMZ) is an oral DNA-alkylating agent used for treating patients with glioblastoma. However, therapeutic benefits of TMZ can be compromised by the expression of O6-methylguanine methyltransferase (MGMT) in tumor tissue. Here we used MGMT-expressing glioblastoma stem cells (GSC) lines as a model for investigating the molecular mechanism underlying TMZ resistance, while aiming to explore a new treatment strategy designed to possibly overcome resistance to the clinically relevant dose of TMZ (35 μM).MethodsMGMT-expressing GSC cultures are resistant to TMZ, and IC50 (half maximal inhibitory concentration) is estimated at around 500 μM. Clonogenic GSC surviving 500 μM TMZ (GSC-500 μM TMZ), were isolated. Molecular signatures were identified via comparative analysis of expression microarray against parental GSC (GSC-parental). The recombinant protein of top downregulated signature was used as a single agent or in combination with TMZ, for evaluating therapeutic effects of treatment of GSC.ResultsThe molecular signatures characterized an activation of protective stress responses in GSC-500 μM TMZ, mainly including biotransformation/detoxification of xenobiotics, blocked endoplasmic reticulum stress-mediated apoptosis, epithelial-to-mesenchymal transition (EMT), and inhibited growth/differentiation. Bone morphogenetic protein 7 (BMP7) was identified as the top down-regulated gene in GSC-500 μM TMZ. Although augmenting BMP7 signaling in GSC by exogenous BMP7 treatment did not effectively stop GSC growth, it markedly sensitized both GSC-500 μM TMZ and GSC-parental to 35 μM TMZ treatment, leading to loss of self-renewal and migration capacity. BMP7 treatment induced senescence of GSC cultures and suppressed mRNA expression of CD133, MGMT, and ATP-binding cassette drug efflux transporters (ABCB1, ABCG2), as well as reconfigured transcriptional profiles in GSC by downregulating genes associated with EMT/migration/invasion, stemness, inflammation/immune response, and cell proliferation/tumorigenesis. BMP7 treatment significantly prolonged survival time of animals intracranially inoculated with GSC when compared to those untreated or treated with TMZ alone (p = 0.0017), whereas combination of two agents further extended animal survival compared to BMP7 alone (p = 0.0489).ConclusionsThese data support the view that reduced endogenous BMP7 expression/signaling in GSC may contribute to maintained stemness, EMT, and chemoresistant phenotype, suggesting that BMP7 treatment may provide a novel strategy in combination with TMZ for an effective treatment of glioblastoma exhibiting unmethylated MGMT

His+ reversions Caused in Salmonella typhimurium by different types of ionizing radiation

The yield of his+ reversions in the Ames Salmonella tester strain TA2638 has been determined for 60Co γ rays, 140 kV X rays, 5.4 keV characteristic X rays, 2.2 MeV protons, 3.1 MeV α particles, and 18 MeV/U Fe ions. Inactivation studies were performed with the same radiations. For both mutation and inactivation, the maximum effectiveness per unit absorbed dose was obtained for the characteristic X rays, which have a dose averaged linear energy transfer (LET) of roughly 10 keV/μm. The ratio of the effectiveness of this radiation to γ rays was 2 for inactivation and about 1.4 for the his+ reversion. For both end points the effectiveness decreases substantially at high LET, i.e., for the α particles and the Fe ions. The composition of the bottom and the top agar was the one recommended by Maron and Ames [Mutat. Res. 113, 173-215 (1983)] for application in chemical mutagenicity tests. The experiments with the less penetrating radiations differed from the usual protocol by utilization of a technique of plating the bacteria on the surface of the top agar. As in an earlier study [Roos et al., Radiat. Res. 104, 102-108 (1985)] greatly enhanced yields of mutations, relative to the spontaneous reversion rate, were obtained in these experiments by performing the irradiations 6 h after plating, which differs from the conventional procedure to irradiate the bacteria shortly after plating

A testability metric for path delay faults and its application

Abstract — In this paper, we propose a new testability metric for path delay faults. The metric is computed efficiently using a non-enumerative algorithm. It has been validated through extensive experiments and the results indicate a strong correlation between the proposed metric and the path delay fault testability of the circuit. We further apply this metric to derive a path delay fault test application scheme for scan-based BIST. The selection of the test scheme is guided by the proposed metric. The experimental results illustrate that the derived test application scheme can achieve a higher path delay fault coverage in scan-based BIST. Because of the effectiveness and efficient computation of this metric, it can be used to derive other design-for-testability techniques for path delay faults. I

Exploring the incidence and variability of oxaliplatin-induced neuropathic pain symptoms in colorectal cancer patients, comparative in vivo / in vitro modelling of oxaliplatin/ 56MESS(IV) as an alternative cancer treatment, and minocycline administration as a prophylactic agent for chemotherapy-induced neuropathic pain

Oxaliplatin is commonly used for the treatment of advanced and recurrent colorectal cancer (CRC). However, oxaliplatin-induced neuropathic pain remains a challenge for the healthcare systems worldwide. In chapter II, the incidence and impact of acute oxaliplatin-induced neuropathic pain on chemotherapy treatment in colorectal cancer patients in the first cycle from the published research literature was explored. In chapter III, the variability of oxaliplatin-induced neuropathic pain symptoms from the Southwestern Sydney Local Health District Hospitals (SWLHDHs) database of patients who received oxaliplatin based chemotherapy treatment (2011-2015) and the implications for the management of colorectal cancer patients was assessed. In chapter IV, it was explored whether oxaliplatin can induce behavioural hypersensitivity in healthy rats using the dosing regimen that mimics the standard clinical protocols (oxaliplatin 2.5 mg/kg i.p every two weeks). In chapter V, the effects of oxaliplatin and 56MESS(IV) on the viability, PI staining (cell death) and activation (nitrite production) of RAW264.7 (macrophages) and N11 (microglia) cell lines were explored in vitro. In summary, oxaliplatin-induced neuropathic pain remains a big problem as it affects treatment compliance in quarter of CRC patients during cycle 1 and as neuropathic pain symptoms oscillate across cycles for individual patients. This warrants further detailed patient-by-patient analysis of pain symptoms in future clinical trials. Additionally, the in vivo and in vitro data showed that minocycline pre-treatment has a potential to ameliorate oxaliplatin and 56MESS(IV) induced production of pro-inflammatory chemical mediators such as nitrite in vitro cell lines, which may be relevant to in vivo models of chemotherapy-induced neuropathic pain. However, oxaliplatin-induced neuropathic pain is more likely multifactorial and research should be continued on the mechanisms of neuropathy and potential therapeutic drugs

Varying the rate of intravenous cocaine infusion influences the temporal dynamics of both drug and dopamine concentrations in the striatum

The faster drugs of abuse reach the brain, the greater is the risk of addiction. Even small differences in the rate of drug delivery can influence outcome. Infusing cocaine intravenously over 5 vs. 90â 100 s promotes sensitization to the psychomotor and incentive motivational effects of the drug and preferentially recruits mesocorticolimbic regions. It remains unclear whether these effects are due to differences in how fast and/or how much drug reaches the brain. Here, we predicted that varying the rate of intravenous cocaine infusion between 5 and 90 s produces different rates of rise of brain drug concentrations, while producing similar peak concentrations. Freely moving male Wistar rats received acute intravenous cocaine infusions (2.0 mg/kg/infusion) over 5, 45 and 90 s. We measured cocaine concentrations in the dorsal striatum using rapidâ sampling microdialysis (1 sample/min) and highâ performance liquid chromatographyâ tandem mass spectrometry. We also measured extracellular concentrations of dopamine and other neurochemicals. Regardless of infusion rate, acute cocaine did not change concentrations of nonâ dopaminergic neurochemicals. Infusion rate did not significantly influence peak concentrations of cocaine or dopamine, but concentrations increased faster following 5â s infusions. We also assessed psychomotor activity as a function of cocaine infusion rate. Infusion rate did not significantly influence total locomotion, but locomotion increased earlier following 5â s infusions. Thus, small differences in the rate of cocaine delivery influence both the rate of rise of drug and dopamine concentrations, and psychomotor activity. A faster rate of rise of drug and dopamine concentrations might be an important issue in making rapidly delivered cocaine more addictive.Varying the rate of i.v. cocaine delivery between 5 and 90 s determines the drug’s effects on brain and behaviour. We show that injecting cocaine between 5 and 90 s in rats alters the rates of rise of cocaine and dopamine in the dorsal striatum, without significantly changing peak concentrations. Faster injections also increase locomotor behaviour earlier than slower injections. Thus, beyond achieved dose, differences in the rates of rise of cocaine and dopamine can determine outcome.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151808/1/ejn13941-sup-0002-reviewer-Comments.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151808/2/ejn13941.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151808/3/ejn13941-sup-0001-FigS1-S3.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151808/4/ejn13941_am.pd

Stimulant drug effects on attention deficit/hyperactivity disorder: a review of the effects of age and sex of patients

Objective: As dopamine functioning varies by sex and age it might be expected that the effects of methylphenidate or amfetamine, the psychostimulants used for the treatment of Attention Deficit /Hyperactivity Disorder (ADHD), will also be moderated by these factors. Here we review the published literature on whether stimulant effects in ADHD symptoms vary by age and sex. Method: We searched for studies published from 1989 until October 2009. Databases searched included U. S. National Library of Medicine (PubMed), Medline, EMBASE, PsycINFO and ISI Web of Knowledge. Firstly, we reviewed the effects of stimulant drugs on male and female patients and also patients of pre-school, middle childhood, adolescence and adulthood. Secondly, we reviewed studies that directly tested the moderating effect of age and sex on stimulant treatment outcome. Results: Randomised controlled trials confirm that stimulant medication is efficacious for, and well tolerated by, males and females and patients across the age range; although preschoolers appear to have a less beneficial response and more side effects. Few studies that specifically examined the moderating effect of age and/or sex were identified. For sex, no effects on overall response were found, although one study reported that sex moderated methylphenidate pharmacodynamics. The few effects found for age were small and inconsistent. Conclusions: The available evidence suggests that stimulant medication, when appropriately administered, has efficacy as an ADHD treatment for both sexes and across all ages. There are currently too few published papers examining the effects of sex and age to draw strong conclusions about moderation. Further studies of the pharmacodynamics of stimulants on symptoms measured using objective tests in the laboratory or classroom setting need to be undertaken