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Exposure to amphetamine in rats during periadolescence establishes behavioural and extrastriatal neural sensitization in adulthood.

Drug abuse during adolescence may predispose towards later adult substance abuse and major depressive disorders (Brook et al., 2002). The purpose of the present study was to characterize whether behavioural sensitization to amphetamine occurred in adult rats following adolescent exposure to amphetamine [low (2 mg/kg.d) or high (10 mg/kg.d) i.p. for 10 d] and the pattern of neural activation associated with sensitized behaviour, in male Sprague-Dawley rats. Following initial treatment (post-natal days 33-41) and a subsequent 4-wk period of abstinence, rats initially treated with either amphetamine regime showed a similar sensitized locomotor activity upon re-challenge with amphetamine (1.5 mg/kg i.p.) compared to rats acutely challenged with this dose of amphetamine. Fos-IR expression in the "high" sensitized group was significantly greater than acutely challenged rats in all quadrants of the CPu. Both "low" and "high" sensitized groups demonstrated heightened Fos expression relative to acutely challenged rats in the medial and central amygdala, as well as rostroventrolateral medulla, whereas Fos-IR in the locus coeruleus and substantia nigra pars reticulata was significantly increased only in the "high" sensitized group compared to acute. Double-labelling for tyrosine hydroxylase confirmed an absence of Fos-IR in A9 and A10 regions. The present study has shown a robust and persistent sensitization in adulthood to amphetamine re-challenge following initial adolescent exposure in rats. This manifestation of sensitization apparently results in widespread neural activation in limbic and autonomic structures.

Age Factors↗

The radiomimetic enediyne C-1027 induces unusual DNA damage responses to double-strand breaks.

Cells lacking the protein kinase ataxia telangiectasia mutated (ATM) have defective responses to DNA double-strand breaks (DSBs), including an inability to activate damage response proteins such as p53. However, we previously showed that cells lacking ATM robustly activate p53 in response to DNA strand breaks induced by the radiomimetic enediyne C-1027. To gain insight into the nature of C-1027-induced ATM-independent damage responses to DNA DSBs, we further examined the molecular mechanisms underlying the cellular response to this unique radiomimetic agent. Like ionizing radiation (IR) and other radiomimetics, breaks induced by C-1027 efficiently activate ATM by phosphorylation at Ser1981, yet unlike other radiomimetics and IR, DNA breaks induced by C-1027 result in normal phosphorylation of p53 and the cell cycle checkpoint kinases (Chk1 and Chk2) in the absence of ATM. In the presence of ATM, but under ATM and Rad3-related kinase (ATR) deficient conditions, C-1027 treatment resulted in a decrease in the level of Chk1 phosphorylation but not in the level of p53 and Chk2 phosphorylation. Only when cells were deficient in both ATM and ATR was there a reduction in the level of phosphorylation of each of these DNA damage response proteins. This reduction was also accompanied by an increased level of cell death in comparison to that of wild-type cells or cells lacking either ATM or ATR. Our findings demonstrate a unique cellular response to C-1027-induced DNA DSBs in that DNA damage response proteins are unaffected by the absence of ATM, as long as ATR is present.

Amino Acids, Cyclic↗

Differential foci and synaptic organization of the principal and spinal trigeminal projections to the thalamus in the rat.

The thalamus is known to receive single-whisker 'lemniscal' inputs from the trigeminal nucleus principalis (PrV) and multiwhisker 'paralemniscal' inputs from the spinal trigeminal nucleus (SpV), yet the responses of cells in the thalamic ventroposteromedial nucleus (VPM) are most similar to and contingent upon inputs from PrV. This may reflect a differential termination pattern, density and/or synaptic organization of PrV and SpV projections. This hypothesis was tested in adult rats using anterograde double-labelling with fluorescent dextrans, horseradish peroxidase (HRP) and choleragenoid, referenced against parvalbumin and calbindin immunoreactivity. The results indicated that PrV's most robust thalamic projection is to the whisker-related barreloids of VPM. The SpV had robust projections to non-barreloid thalamic regions, including the VPM 'shell' encapsulating the barreloid area, a caudal and ventral region of VPM that lacks barreloids and PrV inputs, the posterior thalamic nucleus, nucleus submedius and zona incerta. Within the barreloid portion of VPM, SpV projections were sparse relative to those from PrV, and most terminal labelling occurred in the peripheral fringes of whisker-related patches and in interbarreloid septae. Thus, PrV and SpV have largely complementary projection foci in the thalamus. Intra-axonal staining of a small sample of trigeminothalamic axons with whisker or guard hair receptive fields revealed highly localized and somatotopic terminal aggregates in VPM that spanned areas no larger than that of a single barreloid. In the electron microscopic component of this study, HRP transport to the barreloid region of VPM from left SpV and right PrV in the same cases revealed PrV terminals contacting dendrites with a broad range of minor axis diameters (mean +/- SD: 1.51 +/- 0.10 microns). SpV terminals were indistinguishable from those of PrV, but they had a disproportionate number of contacts on narrow dendrites (1.27 +/- 0.07 microns, P < 0.01). PrV endings were also more likely to contact VPM somata (11.0 +/- 4.2% of all labelled terminals) than those from SpV (3.0 +/- 1.0%, P < 0.01). Insofar as primary dendrites are thicker than distal dendrites in VPM, these data suggest a differential distribution of PrV and SpV inputs onto VPM cells that may account for their relative efficacies in dictating the responses of VPM cells to whisker stimulation. Multiwhisker receptive fields in VPM may also reflect direct transmission of convergent inputs from PrV.

Animals↗

VEGF is necessary for exercise-induced adult hippocampal neurogenesis.

Declining learning and memory function is associated with the attenuation of adult hippocampal neurogenesis. As in humans, chronic stress or depression in animals is accompanied by hippocampal dysfunction, and neurogenesis is correspondingly down regulated, in part, by the activity of the hypothalamic-pituitary-adrenal axis as well as glutamatergic and serotonergic networks. Antidepressants can reverse this effect over time but one of the most clinically effective moderators of stress or depression and robust stimulators of neurogenesis is simple voluntary physical exercise such as running. Curiously, running also elevates circulating stress hormone levels yet neurogenesis is doubled in running animals. In evaluating the signalling that running provides to the central nervous system in mice, we have found that peripheral vascular endothelial growth factor (VEGF) is necessary for the effects of running on adult hippocampal neurogenesis. Peripheral blockade of VEGF abolished running-induced neurogenesis but had no detectable effect on baseline neurogenesis in non-running animals. These data suggest that VEGF is an important element of a 'somatic regulator' of adult neurogenesis and that these somatic signalling networks can function independently of the central regulatory networks that are typically considered in the context of hippocampal neurogenesis.

Animals↗

Is some provider advice on smoking cessation better than no advice? An instrumental variable analysis of the 2001 National Health Interview Survey.

RESEARCH OBJECTIVE: To estimate the effect of provider advice in routine clinical contacts on patient smoking cessation outcome. DATA SOURCE: The Sample Adult File from the 2001 National Health Interview Survey. We focus on adult patients who were either current smokers or quit during the last 12 months and had some contact with the health care providers or facilities they most often went to for acute or preventive care. STUDY DESIGN: We estimate a joint model of self-reported smoking cessation and ever receiving advice to quit during medical visits in the past 12 months. Because providers are more likely to advise heavier smokers and/or patients already diagnosed with smoking-related conditions, we use provider advice for diet/nutrition and for physical activity reported by the same patient as instrumental variables for smoking cessation advice to mitigate the selection bias. We conduct additional analyses to examine the robustness of our estimate against the various scenarios by which the exclusion restriction of the instrumental variables may fail. PRINCIPAL FINDINGS: Provider advice doubles the chances of success in (self-reported) smoking cessation by their patients. The probability of quitting by the end of the 12-month reference period increased from 6.9 to 14.7 percent, an effect that is of both statistical (p < .001) and clinical significance. CONCLUSIONS: Provider advice delivered in routine practice settings has a substantial effect on the success rate of smoking cessation among smoking patients. Providing advice consistently to all smoking patients, compared with routine care, is more effective than doubling the federal excise tax and, in the longer run, likely to outperform some of the other tobacco control policies such as banning smoking in private workplaces.

Adult↗

Contrast-enhanced carotid magnetic resonance angiography: comparison of single-dose and double-dose of gadolinium using the randomly segmented central k-space ordering technique.

BACKGROUND: The aim of this study was to evaluate whether the single dose of gadolinium is sufficient for contrast-enhanced magnetic resonance angiography (MRA) of carotid arteries with the use of newly developed randomly segmented central k-space ordering technique called contrast-enhanced timing-robust angiography (CENTRA). METHODS: A total of 44 patients underwent carotid MRA in a 1.5T MR scanner using a fluoroscopically monitored, manually triggered, CENTRA pulse sequence. Patients were randomly assigned into two groups according to the dose of contrast medium (gadolinium chelate) administered: group 1 referred to those who received double doses (0.2 mmol/kg) and group 2 received single doses (0.1 mmol/kg). The contrast-to-noise (CNR) ratios of the seven regions of interest were calculated. The delineation of nine vascular regions and the degree of venous overlay were evaluated by two blinded readers on a five-point scale. RESULTS: For quantitative evaluation, the CNRs at the brachiocephalic artery were greater in patients in group 1 than that in group 2 (p = 0.015), while the differences did not differ between the two groups for the remaining regions of interest (p > 0.05). For qualitative evaluation, there were no significant differences between the two groups in delineation of nine vascular regions and venous overlaying (p > 0.05). CONCLUSION: With the use of the CENTRA technique, carotid MRA may be performed using a single dose of gadolinium and the image quality is comparable to that of the standard double dose protocol.

Adult↗

An advanced evenly-spaced streamline placement algorithm.

This paper presents an advanced evenly-spaced streamline placement algorithm for fast, high-quality, and robust layout of flow lines. A fourth-order Runge-Kutta integrator with adaptive step size and error control is employed for rapid accurate streamline advection. Cubic Hermite polynomial interpolation with large sample-spacing is adopted to create fewer evenly-spaced samples along each streamline to reduce the amount of distance checking. We propose two methods to enhance placement quality. Double queues are used to prioritize topological seeding and to favor long streamlines to minimize discontinuities. Adaptive distance control based on the local flow variance is explored to reduce cavities. Furthermore, we propose a universal, effective, fast, and robust loop detection strategy to address closed and spiraling streamlines. Our algorithm is an order-of-magnitude faster than Jobard and Lefer's algorithm with better placement quality and over 5 times faster than Mebarki et al.'s algorithm with comparable placement quality, but with a more robust solution to loop detection.

Journal Article↗

Risperidone and paroxetine given singly and in combination for bipolar depression.

BACKGROUND: Bipolar depression is a major clinical problem that remains under-researched. The current study was intended to evaluate the effects of the novel antipsychotic risperidone, the selective serotonin reup-take inhibitor (SSRI) paroxetine, and the combination in patients with bipolar disorder. METHOD: Thirty patients with DSM-IV bipolar (I or II) disorder, depressed phase, who were receiving a stable dose of a mood stabilizer were randomly assigned to 12 weeks of double-blind treatment with risperidone (plus placebo), paroxetine (plus placebo), or the combination of risperidone and paroxetine. Data were gathered from August 1999 to September 2001. RESULTS: All 3 groups experienced significant reductions in depression ratings from baseline to endpoint; there were no significant differences in outcome between groups. There were statistically significant differences in paroxetine dose contrasting paroxetine plus placebo against the combined condition. The switch rate into mania or hypomania was very low, with only 1 patient in the paroxetine plus placebo condition experiencing mild hypomania. CONCLUSION: These results suggest that risperidone, paroxetine, and the combination of risperidone and paroxetine are equally but modestly effective when added to a mood stabilizer in bipolar depression. The paroxetine dose differed between groups, possibly because of drug-drug interactions. Using another SSRI in the combined condition could have produced a more robust effect and should be tested.

Adult↗

Hormone-induced changes in identified cell populations of the higher vocal center in male canaries.

Male canaries revise their vocal repertoire every year. Early work indicated that the volume and neuron number of the song-control nucleus HVC (Higher Vocal Center) declined in late-summer/fall as birds added and deleted syllables from their repertoire, and increased in spring as the set of song syllables stabilized to a fixed number. Seasonal variation in serum testosterone levels suggested that these changes in brain and behavior were regulated by testosterone (T). However, although initial studies describing growth and regression of HVC used Nissl-staining to define its borders, recent experiments that have measured the distribution of identified populations of HVC cells (projection neurons, hormone target cells) suggest that there are no seasonal changes in HVC volume or neuron number. In order to clarify the role of T in the regulation of HVC morphology, we castrated male canaries, maintained them on short (fall-like) days, and treated them with either T, antisteroid drugs, or nothing. After 1 month of treatment, we used a double-labeling technique to characterize HVC projection neurons and androgen target cells. The results showed that hormonal manipulation influenced HVC volume, the density and size of HVC cells, and the absolute number and percentage of androgen target cells in HVC. Hormonal manipulation did not influence the absolute number of cells in HVC. Moreover, the distribution of projection neurons, androgen target cells, and the Nissl-defined borders of HVC were closely aligned in all experimental groups, indicating that exposure to T and/or its metabolites (estradiol and dihydrotestosterone) regulates the overall size of HVC by affecting the distributions of both projection neurons and androgen target cells. Analysis of double-labeling results suggests that T specifically influences both cell size and the ability to accumulate androgen among HVC neurons that project to the robust nucleus of the archistriatum (RA). The results of this study show that steroid hormones exert potent effects on HVC morphology in male canaries, but differences between our results and studies of seasonal males suggest there may be additional factors that can regulate HVC morphology.

Animals↗

Robust regression-based analysis of drug-nucleic acid binding.

Outlier detection can be very important in analyzing data from Scatchard plots. In this study, a robust (outlier-resistant) regression procedure was used in conjunction with a Scatchard plot to study the binding of the methylphenazinium cation with double-stranded DNA. The procedures, their results, and their advantages are discussed.

DNA↗

Evidence for the medullary visceral zone as a neural station of neuroimmunomodulation.

The aim of the present study was to test the possibility that the catecholaminergic projectional pathway from the vagus nerve to the medullary visceral zone (MVZ) thence to the paraventricular nucleus of hypothalamus (PVN) was involved in the cytokine-to-brain communication. A triple labeling method in which WGA-HRP retrograde tracing was combined with anti-Fos and -TH immunohistochemical staining was used. WGA-HRP was stereotaxically injected into unilateral PVN in the rat, after a survival of 48 h, animals received intraperitoneal injection of lipopolysaccharide (LPS). The distribution of the HRP retrogradely labeled neurons, Fos protein positive and catecholaminergic neurons (tyrosine hydroxylase as marker) in the MVZ was observed. Subdiaphragmatic vagotomy (SDV) and sham surgery were also used to observe the different Fos expression in the MVZ after intraperitoneal administration of lipopolysaccharide (LPS) or pyrogen-free saline (NS). Under light microscope, seven types of positively stained neurons could be distinguished within the MVZ, namely neurons single-labeled with Fos, HRP or TH, respectively; neurons double-labeled with Fos/TH, Fos/HRP or HRP/TH separately; and neurons triple-labeled with Fos, HRP and TH staining. Intraperitoneal LPS caused lots of robust Fos expression within the MVZ in the sham surgery groups and this response in the MVZ was markedly inhibited in the vagotomized rats. The results suggested that some catecholaminergic neurons in the MVZ could send projections to the PVN and this pathway might be involved in the relay of peripheral immune information via vagus nerve. MVZ was a neural relay station in the immune-to-brain communication and might play a significant role in the neuroimmunomodulation via vagus-MVZ-PVN pathway.

Animals↗

Bcl-2 mediated suppression of apoptosis in myeloma NS0 cultures.

The influence of Bcl-2 expression on the suppression of apoptosis during the cultivation of an NS0 cell line expressing a chimeric antibody was investigated. Following selection of transfectants in medium containing G418, Western analysis revealed evidence of some up-regulation of endogenous Bcl-2 expression even in the control vector transfectants. Cultivation of the two cell lines in suspension batch cultures clearly demonstrated the enhanced robustness of the bcl-2 vector transfected cells. Suppression of apoptosis resulted in an approximately 20% increase in maximum viable cell number, and a doubling in culture duration compared to the control transfected cells. However, despite the significant affect on viability, Bcl-2 expression did not result in an increase in final antibody titre in comparison with the control cell line. Exposure of cells to various nutrient limited conditions further emphasised the influence of Bcl-2 on cell survival. After 3 days of exposure to serum, glucose, glutamate and asparagine deprivation, the viable cell number and viability were significantly higher in the bcl-2 transfected cell line. When control cells were deprived of all amino acids, there was a complete loss of viability and viable cell number within 3 days. By contrast, the bcl-2 transfected cell line retained greater than 75% of the initial viable cell number and about 70% viability. In response to exposure to 8 mM thymidine (a cytostatic agent) the control cell line underwent complete loss of viability and viable cell number after 6 days. This compared with 18 days for complete loss of viability in the bcl-2 transfected cell line. As under batch culture conditions, there was no difference between the two cell lines in final antibody titre, which indicated that MAb synthesis is limited by nutrient availability during the latter stages of culture in both cases. When fed batch cultures were carried out using a concentrated essential amino acid feed, the bcl-2 cell line exhibited a 60% increase in maximum viable cell number and a 50% increase in culture duration, when compared to the control cell line. Moreover, the bcl-2 cell line exhibited a greater than 40% increase in maximum antibody titre.

Ammonia↗

Co-expression of multiple transgenes in mouse CNS: a comparison of strategies.

The introduction of two transgenes into one animal is increasingly common as transgenic experiments become more sophisticated. In this study we examine two strategies for creating double transgenic founders from a single microinjection. In the first approach, two constructs, each with its own promoter element, were coinjected into the pronucleus. In the second approach, both transgenes were cloned into one vector, separated by an internal ribosomal entry site (IRES), and placed under control of a single promoter. Both strategies save time and increase the percentage of double transgenic offspring over the standard method of mating single transgenic lines. However, despite high transgene copy numbers, the bicistronic lines did not show robust expression of either protein. Copy number and protein expression correlated much better in the coinjected lines, with expression levels in one line approaching that observed in some of our best single transgenic controls. Thus we recommend coinjection of individual plasmids for the generation of multiply transgenic founders.

Amyloid beta-Protein Precursor↗

Daily rhythm in pineal phosphodiesterase (PDE) activity reflects adrenergic/3',5'-cyclic adenosine 5'-monophosphate induction of the PDE4B2 variant.

The pineal gland is a photoneuroendocrine transducer that influences circadian and circannual dynamics of many physiological functions via the daily rhythm in melatonin production and release. Melatonin synthesis is stimulated at night by a photoneural system through which pineal adenylate cyclase is adrenergically activated, resulting in an elevation of cAMP. cAMP enhances melatonin synthesis through actions on several elements of the biosynthetic pathway. cAMP degradation also appears to increase at night due to an increase in phosphodiesterase (PDE) activity, which peaks in the middle of the night. Here, it was found that this nocturnal increase in PDE activity results from an increase in the abundance of PDE4B2 mRNA (approximately 5-fold; doubling time, approximately 2 h). The resulting level is notably higher (>6-fold) than in all other tissues examined, none of which exhibit a robust daily rhythm. The increase in PDE4B2 mRNA is followed by increases in PDE4B2 protein and PDE4 enzyme activity. Results from in vivo and in vitro studies indicate that these changes are due to activation of adrenergic receptors and a cAMP-dependent protein kinase A mechanism. Inhibition of PDE4 activity during the late phase of adrenergic stimulation enhances cAMP and melatonin levels. The evidence that PDE4B2 plays a negative feedback role in adrenergic/cAMP signaling in the pineal gland provides the first proof that cAMP control of PDE4B2 is a physiologically relevant control mechanism in cAMP signaling.

3',5'-Cyclic-AMP Phosphodiesterases↗

Secretin is an ineffective treatment for pervasive developmental disabilities: a review of 15 double-blind randomized controlled trials.

In 1998, Horvath et al. [Horvath, K., Stefanatos, G., Sokolski, K. N., Wachtel, R., Nabors, L., & Tildon, J. T. (1998). Improved social and language skills after secretin administration in patients with autism spectrum disorders. Journal of the Association of the Academy of Minority Physicians, 9, 9-15] reported an uncontrolled trial of secretin with three participants with autism, which apparently resulted in significant behavioral improvement. Subsequently, secretin was widely used. Sandler et al. [Sandler, A. D., Sutton, K. A., SeWeese, J., Girardi, M. A., Sheppard, V., & Bodfish, J. W. (1999). Lack of benefit of a single dose of synthetic human secretin in the treatment of autism and pervasive and developmental disorder. The New England Journal of Medicine, 341, 1801-1806] reported the first double-blind trial of secretin with negative results. This article is a review of 15 double-blind trials of secretin. Almost none of the studies reported any significant effects and none concluded that secretin was effective. Transient effects of secretin, including both minor benefits and behavioral deterioration were reported, probably due to multiple statistical tests. Four papers reported data on differential responding in sub-groups of participants, including those with gastrointestinal symptoms. These effects were not replicable. At this time there is no robust evidence that secretin is an effective treatment for pervasive developmental disorders.

Adolescent↗

The effects of clozapine and high-dose olanzapine on brain function in treatment-resistant schizophrenia: a case study.

Although demonstrating superior efficacy in people with treatment-resistant schizophrenia, clozapine may cause serious side effects, requires blood monitoring and is costly to administer. Olanzapine is similar to clozapine in molecular structure and pharmacologic action but has not demonstrated as robust results as clozapine at routine doses (10-25 mg). Here we present a case study measuring blood flow by positron emission tomography (PET) imaging for a patient treated sequentially with a high dose of olanzapine (50 mg/day) followed by clozapine each for 8 weeks in a double-blind design. During a task, clozapine produced more brain activation patterns than during treatment with olanzapine or during the drug free condition (2 week washout). Clozapine resulted in recruitment of frontal, parietal and cingulate regions that did not appear to be active during olanzapine in this 44 year old right handed male. Additionally, a more robust decrease in symptoms was noted on the Brief Psychiatric Rating Scale (BPRS) score than with olanzapine treatment. These findings suggest that high doses of olanzapine do not produce similar brain activation patterns as clozapine in people with treatment-resistant schizophrenia.

Adult↗

Multicomponent Lyme vaccine: three is not a crowd.

Lyme disease is caused by the spirochete Borrelia burgdorferi and it is the most common vector-borne disease in the United States. Disseminated spirochetes can persist in various tissues and can result in a variety of different disease manifestations. Vaccination trials testing various lipoprotein candidates have yielded mixed results despite the generation of robust antibody titers. Data presented in this report demonstrate that a combination vaccine composed of DbpA, BBK32 and OspC is more effective than single or double component formulations and that the ratio of each component dramatically impacts vaccine efficacy when tested in protection experiments against Borrelia following needle inoculation.

Adhesins, Bacterial↗

Use of a stochastic simulation model to identify an efficient protocol for ovarian cancer screening.

The intervention protocol for an ovarian cancer screening trial should be efficient as well as effective, because it may become the standard of care if the trial demonstrates mortality reduction. To identify an efficient ovarian cancer screening protocol, the effectiveness and cost-effectiveness of selected single modality and multimodal screening strategies were estimated using a stochastic simulation model. Screening was simulated over a 30-year period in a hypothetical cohort of 1 million women aged 50 at the beginning of the period. The net present value of the cost per year of life saved was estimated for six protocols involving transvaginal sonography (TVS) and/or the tumor antigen CA 125. Internal and external validation was performed, and sensitivity analyses were conducted to assess the robustness of the ranking of the strategies. A multimodal strategy involving CA 125 with a threshold for positivity of either elevation above 35 U/ml or doubling since the previous screen, followed by TVS only if CA 125 is positive, was found to be efficient in the sense that no other strategies saved as many years of life at lower cost per year of life saved. Used annually, this strategy cost under $100,000 per year of life saved over a range of assumptions. The model's predictions are consistent with results reported in the literature regarding the performance of TVS and CA 125. The multimodal strategy used annually or every six months was efficient compared to either ultrasound or CA 125 used alone, over a range of assumptions. Simulation of screening may be useful in selecting a screening protocol to be tested in a randomized controlled trial.

Aged↗