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Separate Experiments (separate + experiment)
Selected AbstractsClassical conditioning in the rat fetus: Involvement of mu and kappa opioid systems in the conditioned responseDEVELOPMENTAL PSYCHOBIOLOGY, Issue 2 2002William P. Smotherman Abstract When the Embryonic Day 20 (E20) rat fetus is given a conditioning trial involving a paired presentation of an artificial nipple (the conditioned stimulus; CS) with an intraoral infusion of milk (the unconditioned stimulus; US), it shows evidence of classical conditioning when again exposed to the CS during a test trial. Specifically, the fetus shows fewer oral grasp responses (the conditioned response; CR) when continuously presented with the artificial nipple. The present study further investigated this classically conditioned reduction in oral grasping. Separate experiments (a) examined the time course of the reduction in oral grasping (Experiment 1), (b) characterized the time course of mu opioid (Experiment 2) and kappa opioid (Experiment 3) involvement in the CR, and (c) described changes in fetal behavior (Experiment 4) associated with mu and kappa opioid effects on responding to the artificial nipple. The results are discussed in terms of opioid involvement in establishing and maintaining early suckling behavior. © 2002 Wiley Periodicals, Inc. Dev Psychobiol 40: 104,115, 2002. DOI 10.1002/dev.10016 [source] Antisense oligodeoxynucleotide-induced suppression of basal forebrain NMDA-NR1 subunits selectively impairs visual attentional performance in ratsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 1 2001Janita Turchi Abstract It is generally agreed that basal forebrain neuronal circuits contribute to the mediation of the ability to detect, select and discriminate signals, to suppress the processing of irrelevant information, and to allocate processing resources to competing tasks. Rats were trained in a task designed to assess sustained attention, or in a cued discrimination task that did not tax attentional processes. Animals were equipped with guide cannula to infuse bilaterally antisense oligodeoxynucleotides (ODNs) against the N -methyl- d -aspartate (NMDA) NR1 subunits, or missense ODNs, into the substantia innominata of the basal forebrain. Infusions of antisense or missense ODNs did not affect cued visual discrimination performance. Infusions of antisense ODNs dose-dependently impaired sustained attention performance by selectively decreasing the animals' ability to detect signals while their ability to reject nonsignal trials remained unchanged. The detrimental attentional effects of antisense infusions were maximal 24 h after the third and final infusion, and performance returned to baseline 24 h later. Missense infusions did not affect attentional performance. Separate experiments demonstrated extensive suppression of NR1 subunit immunoreactivity in the substantia innominata. Furthermore, infusions of antisense did not produce neurotoxic effects in that region as demonstrated by the Fluoro-Jade method. The present data support the hypothesis that NMDA receptor (NMDAR) stimulation in the basal forebrain, largely via glutamatergic inputs originating in the prefrontal cortex, represents a necessary mechanism to activate the basal forebrain corticopetal system for mediation of attentional performance. [source] Differences in circular muscle contraction and peristaltic motor inhibition caused by tachykinin NK1 receptor agonists in the guinea-pig small intestineNEUROGASTROENTEROLOGY & MOTILITY, Issue 2 2000Shahbazian The tachykinin NK1 receptor agonist substance P methyl ester (SPOME) impedes intestinal peristalsis by releasing nitric oxide (NO) from inhibitory motor neurones. Since NK1 receptor agonists differ in their receptor interaction, we set out to compare a range of NK1 receptor agonists including SPOME, septide and GR-73 632 in their effects on propulsive peristalsis and circular muscle activity in the guinea-pig isolated small intestine. SPOME (100,300 n M) inhibited peristalsis by a rise of the pressure threshold at which peristaltic waves were triggered, whereas septide and GR-73 632 (30,300 n M) interrupted peristalsis by causing circular muscle spasms. Separate experiments showed that all three NK1 receptor agonists caused contraction of the circular muscle, which was enhanced by the NO synthase inhibitor NG -nitro- L -arginine methyl ester (300 ,M) and the P2X purinoceptor antagonist suramin (300 ,M). In contrast, tetrodotoxin (300 n M) augmented the contractile effect of septide and GR-73 632 but not that of SPOME. It is concluded that the motor response to NK1 receptor agonists involves release of NO and adenosine triphosphate from inhibitory motor neurones. However, the NK1 receptor agonists differ in the mechanism by which they cause inhibitory transmitter release, which corresponds to differences in their antiperistaltic action. [source] Interactions between habitat quality and connectivity affect immigration but not abundance or population growth of the butterfly, Parnassius smintheusOIKOS, Issue 10 2009Stephen F. Matter Habitat geometry has been a primary focus in studies of spatially structured systems. Recent studies have indicated that a more comprehensive approach including habitat quality may be needed, however most previous studies have neglected potential interactions between quality and geometry. We investigated the effects of habitat quality for the butterfly Parnassius smintheus among a series of 17 sub-populations. Specifically, we examined how habitat connectivity and local nectar flower density affect dispersal, and local population abundance and growth. We first determined which flower species were potentially important by examining nectar flower electivity and then quantified nectar flower density in meadows over a five year period (2003,2007). These data along with meadow connectivity were compared to local population statistics derived from mark,recapture over the same time period. The number of immigrants to a meadow increased as meadow connectivity increased, but showed no direct relationship with nectar flower density; however, there was a significant interaction between meadow connectivity and nectar flower density such that meadows with high connectivity and a high density of nectar flowers received the greatest number of immigrants. The number of emigrants from a meadow increased with increasing habitat quality and connectivity, but showed no interactive effect. The abundance of butterflies increased with meadow connectivity, but showed no relationship with habitat quality or any interactive effect. Separate experiments showed that access to nectar flowers significantly increased female reproductive output, but not lifespan. Despite the effects on immigration and reproductive output, local population growth rates also showed no relationship to nectar flower density. Our results indicate that habitat quality can be important for immigration in spatially structured populations; however, effects of habitat quality may not necessarily translate into higher abundance or population growth. Additionally, habitat quality should not be considered independently from habitat isolation, particularly if it directly affects dispersal. Preserving or augmenting habitat quality will do little to bolster immigration or colonization without adequate connectivity. [source] The acute anti-craving effect of acamprosate in alcohol-preferring rats is associated with modulation of the mesolimbic dopamine systemADDICTION BIOLOGY, Issue 3 2005Michael Cowen Acamprosate (Campral ?) is a drug used clinically for the treatment of alcoholism. In order to examine further the time-course and mechanism of action of acamprosate, the effect of acute and repeated acamprosate administration was examined on (i) operant ethanol self-administration and (ii) voluntary home cage ethanol consumption by alcohol-preferring Fawn-Hooded, iP and Alko Alcohol (AA) rats. Acutely, acamprosate was shown to cause a significant decrease in operant ethanol self-administration by Fawn-Hooded and alcohol-preferring iP rats in part by decreasing the motivational relevance of a specific ethanol cue; however, repeated injection of acamprosate led to tolerance to this effect. Voluntary alcohol consumption in the home cage in Fawn-Hooded and AA rats was also reduced by an acute acamprosate injection; however, again tolerance developed to repeated injections. In a separate experiment, the effect of acamprosate on markers of the dopaminergic system was examined. Interestingly, acute acamprosate was also shown to cause increased dopamine transporter density and decreased dopamine D2-like receptor density within the nucleus accumbens but not in the caudate-putamen, suggesting a link between the decreased motivational salience of the ethanol cue and altered dopaminergic signalling within the nucleus accumbens. With repeated injections of acamprosate, markers of the dopaminergic system returned to steady state levels with a similar temporal profile to the development of tolerance in the behavioural studies. Along with previous studies, our findings indicate that acamprosate modulates the mesolimbic dopaminergic system and may thereby decrease ethanol reinforcement processes; however, these effects undergo tolerance in alcohol-preferring rats and may in part explain the fact why some subjects are non-responders to chronic acamprosate treatment. [source] REM sleep: a sensitive index of fear conditioning in ratsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 4 2005Sushil K. Jha Abstract To examine the influence of conditioned fear stimuli on sleep-wake states, we recorded sleep in Sprague,Dawley rats after exposure to tones previously paired with footshock. After habituation to a recording chamber and the recording procedure, a baseline sleep recording was obtained the next day. One day later, experimental animals were exposed to shock training designed to induce conditioned fear (FC), consisting of five tone-footshock pairings. The 5-s tones (conditioned stimuli; CS) co-terminated with 1-s footshocks (unconditioned stimuli; US). The next day sleep was recorded for 4 h in the recording chamber after presentation of five CSs alone. Sleep efficiency (total sleep time/recording period) and REM sleep (REM) and non-REM (NREM) measures were determined. While sleep efficiency was not significantly changed after CS presentation, the percentage of total sleep time spent in REM (REM percentage) was reduced in the FC animals. The reduction in REM percentage in the FC animals was due to a decrease in the number of REM bouts. In a separate experiment, we repeated the procedures, except the tones and shocks were presented in an explicitly unpaired (UP) fashion. The next day, presentation of the tones increased REM percentage in the UP group. Results are discussed in terms of the decreases in REM as a response to conditioned fear, and the relevance of these findings to the sleep changes seen in post-traumatic stress disorder (PTSD). [source] Previous experience of withdrawal from chronic diazepam ameliorates the aversiveness of precipitated withdrawal and reduces withdrawal-induced c-fos expression in nucleus accumbensEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 4 2000Sarah J. Dunworth Abstract Flumazenil (20 mg/kg, i.p.)-precipitated withdrawal from chronic treatment with diazepam (DZP, 15 mg/kg, s.c. in sesame oil for 21 days) resulted in a decreased seizure threshold to the convulsant, pentylenetetrazole (PTZ), infused into the tail vein; withdrawal from 21-day chronic diazepam treatment, interspersed with two periods of drug withdrawal, resulted in a greater decrease in convulsant threshold. A separate experiment showed that consumption of a sucrose solution immediately prior to precipitated withdrawal resulted in a decreased subsequent consumption of the sucrose solution; no such evidence of a conditioned taste aversion (CTA) was seen in mice given prior experience of withdrawal. Thus, prior experience of withdrawal enhanced the effects of a subsequent precipitated withdrawal in increasing seizure sensitivity, but weakened the ability of this withdrawal to serve as an aversive unconditioned stimulus (US). The weakening of the aversive properties of precipitated withdrawal may reflect habituation to the withdrawal stimulus, and was accompanied by a loss of the ability of withdrawal to induce c-fos expression in the shell of the nucleus accumbens, an area sensitive to both novel, and stressful, as well as rewarding stimuli. [source] The lateral-occipital and the inferior-frontal cortex play different roles during the naming of visually presented objectsHUMAN BRAIN MAPPING, Issue 12 2009Philippe A. Chouinard Abstract We reasoned that if an area is devoted to processing only the visual features of objects, then transcranial magnetic stimulation (TMS) applied to this area in either hemisphere would affect the naming of objects presented in contralateral but not ipsilateral space. In contrast, if an area is involved in language, then one might expect to see effects of TMS when applied over the left but not the right hemisphere, regardless whether objects are in contralateral or ipsilateral space. Our experiments reveal two important findings. First, TMS delivered to the lateral-occipital complex (LOC), a visual-form area, affected the naming of objects presented in contralateral but not ipsilateral space, independent of which hemisphere was stimulated. In two additional experiments, when participants named the color of objects or made judgments about the size of stimuli as shown physically on a computer screen, TMS over the contralateral LOC did not affect color naming but did affect the participants' ability to make size judgments. Second, TMS delivered to the left but not the right posterior inferior-frontal gyrus (pIFG) affected the naming of objects irrespective of whether objects were presented in contralateral or ipsilateral space. In a separate experiment, when participants were asked to either read or categorize words, TMS over the left but not the right pIFG affected word categorization but not word reading. On the basis of these findings, we propose that when people name visually-presented objects, LOC processes the visual form of objects while the left pIFG processes the semantics of objects. Hum Brain Mapp, 2009. © 2009 Wiley-Liss, Inc. [source] Effects of elevated carbon dioxide and increased nitrogen deposition on bog vegetation in the NetherlandsJOURNAL OF ECOLOGY, Issue 2 2001Monique M. P. D. Heijmans Summary 1,We studied the effects of elevated atmospheric CO2 and increased N deposition on the plant species composition of a Sphagnum -dominated bog ecosystem in the Netherlands. Large peat monoliths (surface area 1 m2, depth 0.6 m) with intact bog vegetation were kept outdoors in large containers and were exposed to elevated CO2 or increased N deposition for three growing seasons. Elevated CO2 conditions (target concentration 560 µmol CO2 mol,1) were created using MiniFACE technology. In a separate experiment, N deposition was increased by 5 g N m,2 year,1 by adding dissolved NH4NO3 at 3 week intervals during the growing season. 2,Elevated atmospheric CO2 increased height growth of Sphagnum magellanicum, the dominant Sphagnum species, in the second and third growing seasons. Vascular plant biomass was not significantly affected by elevated CO2, but growth of species growing close to the moss surface was influenced negatively by the increased Sphagnum height growth. Elevated CO2 did not change allocation to below-ground plant parts. 3,Adding N increased above-ground vascular plant biomass. The shallow-rooted species Vaccinium oxycoccus responded most to the increased N deposition. Sphagnum growth was significantly reduced in the third growing season. This reduction was likely the result of the increased vascular plant cover, given the observed negative relation between vascular plant cover and Sphagnum growth. 4,The observed shifts in species composition as a result of species-specific responses to treatments, and interactions between peat mosses and vascular plants will have important consequences for the sequestration of carbon in the bog ecosystem. [source] Inhibition by Lipopolysaccharide of Naloxone-Induced Luteinising Hormone Secretion Is Accompanied by Increases in Corticotropin-Releasing Factor Immunoreactivity in Hypothalamic Paraventricular Neurones in Female RatsJOURNAL OF NEUROENDOCRINOLOGY, Issue 2 2005D. He Abstract We have recently reported that lipopolysaccharide (LPS), a bacterial endotoxin, inhibits steroid-induced as well as naloxone-induced luteinising hormone (LH) secretion in ovariectomised oestrogen-primed rats. In the present study, we examined whether corticotropin-releasing factor (CRF) may be involved in the LPS-induced inhibition of LH secretion. Unanaesthetised rats were treated with an intravenous (i.v.) injection of LPS (10 µg) or saline, followed by an i.v. injection of naloxone (20 mg/kg). After sequential blood samples were collected for determination of serum LH concentrations, the brains were fixed and CRF-immunoreactivity was examined histochemically. In control rats receiving saline injections, only a small number of CRF-immunoreactive (ir) cells were found in the parvocellular portion of the hypothalamic paraventricular nucleus (PVN), and naloxone significantly increased serum LH concentrations within 10 min. By contrast, in LPS-treated rats, the number of CRF-ir cells was significantly greater than that in control rats, and the effect of naloxone was completely abolished. In a separate experiment, an intracerebroventricular injection of 5 µg CRF inhibited naloxone-induced LH release, mimicking the effect of LPS. These results suggest that LPS stimulates production of CRF in PVN neurones, which in turn inhibits LH secretion without opioidergic mediation. [source] PRG4 exchange between the articular cartilage surface and synovial fluidJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 10 2007G.E. Nugent-Derfus Abstract The boundary lubrication function of articular cartilage is mediated in part by proteoglycan 4 (PRG4) molecules, found both in synovial fluid (SF) and bound to the articular cartilage surface. Currently the mechanism by which PRG4 binds to the articular surface is not well understood. The objectives of this study were to determine (1) the effect of bathing fluid contents on PRG4 concentration at the articular surface ([PRG4]cart), and (2) whether native PRG4 can be removed from the surface and subsequently repleted with PRG4 from synovial fluid. In one experiment, cylindrical cartilage disks were stored in solutions of various PRG4 concentrations, either in phosphate-buffered saline (PBS) or SF as the carrier fluid. In a separate experiment, cartilage disks were stored in solutions expected to remove native PRG4 from the articular surface and allow subsequent repletion with PRG4 from SF. [PRG4]cart was independent of PRG4 concentration of the bathing fluid, and was similar for both carrier fluids. PRG4 was removed from cartilage by treatment with hyaluronidase, reduction/alkylation, and sodium dodecyl sulphate, and was repleted fully by subsequent bathing in SF. These results suggest that the articular surface is normally saturated with tightly bound PRG4, but this PRG4 can exchange with the PRG4 in SF under certain conditions. This finding suggests that all tissues surrounding the joint cavity that secrete PRG4 into the SF may help to maintain lubrication function at the articular surface. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:1269,1276, 2007 [source] C-Peptide Deficiency: An Important Pathogenetic Factor In Type 1 Diabetic NeuropathyJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 3 2000Aaf Sima Background: C-peptide has insulin-like effects and ameliorates the acute nerve conduction defect (NCD) in experimental and human type 1 diabetic neuropathy (DN). Methods: In this study, diabetic BB/Wor-rats were treated with rat C-peptide (75 ng/kg) from onset of diabetes for 8 months (prevention-group, PG). In a separate experiment, 5-mo untreated diabetic BB/Wor-rats were started on the same C-peptide treatment continued to 8 mo of diabetes (intervention group, IG). Results: In the PG, the NCD was significantly decreased (p < 0.001) compared to untreated BB/Wor-rats and was similar to that of normo-C-peptidemic and isohyperglycemic type 2 BBZ rats. This effect was associated with significant preventions of nodal changes (p < 0.001) including axo-glial dysjunction (p < 0.001), which was not different from non-diabetic control rats. Axonal atrophy and Wallerian degeneration were significantly prevented (both p < 0.05). In the IG, the NCD decreased significantly (p < 0.01) during the 3 mo treatment period. Associated with the functional improvement, nodal changes improved significantly (p < 0.001) as did axonal degenerative changes (p < 0.01). C-peptide treatment in the IG resulted in a significant increase in the frequency of regenerating fibers (p < 0.001) compared with untreated 5 mo diabetic rats. Conclusion: These studies demonstrate that C-peptide replacement in type 1 diabetes prevents the chronic NCD and structural changes. Furthermore, C-peptide treatment significantly improves the already established functional and structural abnormalities of DN. This is the first demonstration of a therapeutic improvement of established neuropathy in experimental diabetes. We conclude that C-peptide deficiency in type 1 diabetes is an important pathogenetic component of DN and that its replacement may provide a valuable adjunct to intensive insulin treatment. [source] Interaction of live and dead Escherichia coli O157:H7 and fluorescent microspheres with lettuce tissue suggests bacterial processes do not mediate adherenceLETTERS IN APPLIED MICROBIOLOGY, Issue 2 2006E.B. Solomon Abstract Aims:, The goal of this study was to determine whether any specific bacterial processes (biochemical or genetic) or cell surface moieties were required for the interaction between Escherichia coli O157:H7 and lettuce plant tissue. Methods and Results:,Escherichia coli O157:H7 and FluospheresTM (fluorescent polystyrene microspheres) were used in experiments to investigate interactions with lettuce. FluospheresTM were used as they are a nonbiological material, of similar size and shape to a bacterial cell, but lack bacterial cell surface moieties and the ability to respond genetically. Live and glutaraldehyde-killed E. coli O157:H7 attached at levels of c. 5·8 log10 cells per cm2 following immersion of lettuce pieces into a suspension containing c. 8 log10 CFU ml,1. In a separate experiment, numbers of bacteria or FluospheresTM associated with lettuce decreased by c. 1·5 log cm,2 following a 1-min wash. Exposure times of 1 min, 1 h, or 6 h had little effect on the level of attachment for FluospheresTM, and live or killed cells of E. coli O157:H7 to lettuce tissue. Significance:, These results indicate that bacterial processes and cell surface moieties are not required for the initial interaction of E. coli O157:H7 to lettuce plant tissue. [source] Caspase inhibition increases survival of neural stem cells in the gastrointestinal tractNEUROGASTROENTEROLOGY & MOTILITY, Issue 4 2005M.-a . Micci Abstract, Neural stem cell (NSC) transplantation is a promising tool for the restoration of the enteric nervous system in a variety of motility disorders. Post-transplant survival represents a critical limiting factor for successful repopulation. The aim of this study was to determine the role of both immunological as well as non-immune-mediated mechanisms on post-transplant survival of NSC in the gut. Mouse CNS-derived NSC (CNS-NSC) were transplanted into the pylorus of recipient mice with and without the addition of a caspase-1 inhibitor (Ac-YVAD-cmk) in the injection media. In a separate experiment, CNS-NSC were transplanted in the pylorus of mice that were immunosuppressed by administration of cyclosporin A (CsA). Apoptosis and proliferation of the implanted cells was assessed 1 and 7 days post-transplantation. Survival was assessed 1 week post-transplantation. The degree of immunoresponse was also measured. The addition of a caspase-1 inhibitor significantly reduced apoptosis, increased proliferation and enhanced survival of CNS-NSC. CsA-treatment did not result in improved survival. Our results indicate that caspase-1 inhibition, but not immunosuppression, improves survival of CNS-NSC in the gut. Pre-treatment with a caspase-1 inhibitor may be a practical method to enhance the ability of transplanted CNS-NSC to survive in their new environment. [source] Modulatory Effects of Transcranial Direct Current Stimulation on Laser-Evoked PotentialsPAIN MEDICINE, Issue 1 2009Gabor Csifcsak MD ABSTRACT Objective., Invasive stimulation of the motor cortex has been used for years to alleviate chronic intractable pain in humans. In our study, we have investigated the effect of transcranial direct current stimulation (tDCS), a noninvasive stimulation method, for manipulating the excitability of cortical motor areas on laser evoked potentials (LEP) and acute pain perception. Designs and Settings., The amplitude of the N1, N2, and P2 LEP components of 10 healthy volunteers were evaluated prior to and following anodal, cathodal, and sham stimulation of the primary motor cortex. In a separate experiment subjective, pain rating scores of 16 healthy subjects in two perceptual categories (warm sensation, mild pain) were also analyzed. Results., Cathodal tDCS significantly reduced the amplitude of N2 and P2 components compared with anodal or sham stimulation. However, neither of the tDCS types modified significantly the laser energy values necessary to induce moderate pain. In a separate experiment, cathodal stimulation significantly diminished mild pain sensation only when laser-stimulating the hand contralateral to the side of tDCS, while anodal stimulation modified warm sensation. Conclusions., The possible underlying mechanisms of our findings in view of recent neuroimaging studies are discussed. To our knowledge this study is the first to demonstrate the mild antinociceptive effect of tDCS over the primary motor cortex in healthy volunteers. [source] A combined agar-absorption and BIO-PCR assay for rapid, sensitive detection of Xylella fastidiosa in grape and citrusPLANT PATHOLOGY, Issue 1 2005M. Fatmi Application of the polymerase chain reaction (PCR) to disease diagnosis is limited in part by the presence of PCR inhibitors. Inhibition can be overcome and sensitivity increased by culturing bacteria on agar media prior to PCR (termed BIO-PCR). However, Xylella fastidiosa grows slowly, requiring 10,14 days for visible colonies to appear. In this study an agar-absorption BIO-PCR method for detecting X. fastidiosa in grape and citrus plants was developed. Optimum lengths of time for absorption of inhibitors by the agar medium or enrichment of bacteria on the medium were determined for Pierce's disease of grape and citrus variegated chlorosis. When petioles of grape and citrus leaves with symptoms were spotted onto agar media, the spots washed after various time intervals and assayed for X. fastidiosa by real-time PCR, 97% (31 out of 32) and 100% (six out of six) of spots were positive after 2 days and 4 h for grape and citrus, respectively. With direct PCR, only 12·5% (four out of 32) and 33% (two out of six) of spots were positive, respectively, and visible X. fastidiosa colonies were evident after 10 and 14 days, respectively. In a separate experiment with samples from a different vineyard, 46% (13 out of 28) of the grape samples (agar spots) were positive after 1 day and 93% (26 out of 28) after 5 days using agar-absorption PCR. In contrast, all samples were negative by direct PCR. Viable X. fastidiosa were recovered from all samples after 14 days. Further tests with eight randomly selected grape petioles from three Texas vineyards known to have Pierce's disease resulted in 50% being positive by a simple 24 h agar-absorption PCR assay, whereas none was positive by direct PCR. Overall, 10 out of 16 (63%) vines from five vineyards (two in California and three in Texas) were positive after the 24 h agar-absorption PCR assay. In contrast, only one vine was positive by direct PCR. This simple agar absorption-based PCR assay protocol should prove useful for the routine detection of X. fastidiosa and other slow-growing bacteria in the presence of PCR inhibitors. [source] Telomerase enzyme inhibition (TEI) and cytolytic therapy in the management of androgen independent osseous metastatic prostate cancerTHE PROSTATE, Issue 6 2010Yingming Li Abstract BACKGROUND Recurrent prostate cancer can be osseous, androgen independent and lethal. The purpose is to discern the efficacy of synthetic small molecule telomerase enzyme inhibitors (TEI) alone or in combination with other cytotoxic therapies in controlling metastatic osseous prostate cancer. METHODS C4-2B was pre-treated with a match or mismatch TEI for 6 weeks and then inoculated into nude mice subcutaneously or intraosseously. In a separate experiment, untreated C4-2B was injected into femur of nude mice. The mice were divided into seven systemic "combination" treatment groups of control, Ad-BSP-E1a virus, docetaxel, mismatch and match TEI. Serum PSA was followed longitudinally. Histology analyses and histomorphometry were performed. Repeated measure analysis was applied for statistical analysis and Bonferroni method was used in multiple comparisons. RESULTS In the pre-treated study, the PSA of match treated cells in subcutaneous or intraosseous model was significantly lower than mismatch TEI or PBS treated group (P,<,0.05). Histology revealed increased fibrosis, apoptosis and decreased PSA staining in the match TEI treated subcutaneous xenografts. In the combination treatment study, the PSA was significantly lower in single/double treatment and triple treatment than control (P,<,0.05). Histology revealed that triple therapy mice had normal femur architecture. Histomorphometrics revealed that the area of femur tumor and woven bone was significantly positively correlated (P,=,0.007). CONCLUSIONS Multiple lines of data point toward the efficacy of systemically administered telomerase inhibitors. Combining cytotoxic regimens with telomerase inhibitors could be beneficial in controlling prostate cancer. Clinical trials are warranted to explore the efficacy of TEI in prostate cancer. Prostate 70: 616,629, 2010. © 2009 Wiley-Liss, Inc. [source] Evaluation of tracheal tube introducers in simulated difficult intubation,ANAESTHESIA, Issue 3 2009C. Janakiraman Summary In a randomised cross-over study, 72 anaesthetists attempted to place Pro-Breathe, new Portex, and Frova single-use tracheal tube introducers and an Eschmann multiple-use introducer in the trachea of a manikin set to simulate a grade 3 laryngeal view. Successful placement (proportion, 95% confidence interval) of either the Frova (78%, 67,86%) or the Eschmann introducer (64%, 52,74%) was significantly more likely (p < 0.0001) than with the Pro-Breathe (4%, 1,12%) or the new Portex introducer (13%, 7,22%). The difference between the success rates for the Frova and the Eschmann introducers (p = 0.08) was not significant. A separate experiment revealed that the peak force that could be exerted by the Pro-Breathe, new Portex and Frova single-use introducers were three to six times greater than that which could be exerted by the Eschmann introducer (p < 0.0001). The single-use introducers are more likely to cause tissue trauma during placement, particularly if held close to the tip. [source] Protein to carbohydrate ratio in high-energy diets for Atlantic salmon (Salmo salar L.)AQUACULTURE RESEARCH, Issue 7 2001Marie Hillestad Abstract The effect of dietary protein to carbohydrate ratios (P/CH, weight percentage) of P34/CH21, P39/CH15 and P44/CH10 was studied in Atlantic salmon (Salmo salar L.) with respect to growth and feed conversion ratio (FCR) in one medium-scale experiment (Experiment 1) and to slaughter quality in two production scale experiments (Experiments 2A and 2B). The dietary fat was maintained at 290 g kg,1 whereas the protein (fish meal) was exchanged with carbohydrate (wheat). Fish grown from approximately 1 to 4 kg were fed a restricted diet (iso-energetic on gross energy basis) or to satiation. Nitrogen, fat, starch and energy digestibilities were measured in a separate experiment. There were slight tendencies for lower growth (P = 0.06) and for higher FCRs (P = 0.06) in Experiment 1, and a slight tendency for a lower dress-out percentage in Experiments 2A and 2B (P = 0.10 and 0.20 respectively) with decreasing P/CH. The P/CH had no effect on the fat concentration of fillets, flesh colour or sexual maturation. The digestibility of starch decreased from 62.1% to 46.1% and the digestibility of energy from 84.9% to 79.5% when P/CH decreased from P44/CH10 to P34/CH21. Growth per unit digestible protein increased with decreasing P/CH. Feeding to satiation improved the growth but the FCR was higher than it was for restricted feeding. The calculated starch load per kg of fish growth increased with decreasing P/CH, whereas the effluent nitrogen decreased. [source] Intensified Process for the Purification of an Enzyme from Inclusion Bodies Using Integrated Expanded Bed Adsorption and RefoldingBIOTECHNOLOGY PROGRESS, Issue 4 2006Matthew H. Hutchinson This work describes the integration of expanded bed adsorption (EBA) and adsorptive protein refolding operations in an intensified process used to recover purified and biologically active proteins from inclusion bodies expressed in E. coli. ,5 -3-Ketosteroid isomerase with a C-terminal hexahistidine tag was expressed as inclusion bodies in the cytoplasm of E. coli. Chemical extraction was used to disrupt the host cells and simultaneously solubilize the inclusion bodies, after which EBA utilizing immobilized metal affinity interactions was used to purify the polyhistidine-tagged protein. Adsorptive refolding was then initiated in the column by changing the denaturant concentration in the feed stream from 8 to 0 M urea. Three strategies were tested for performing the refolding step in the EBA column: (i) the denaturant was removed using a step change in feed-buffer composition, (ii) the denaturant was gradually removed using a gradient change in feed-buffer composition, and (iii) the liquid flow direction through the column was reversed and adsorptive refolding performed in the packed bed. Buoyancy-induced mixing disrupted the operation of the expanded bed when adsorptive refolding was performed using either a step change or a rapid gradient change in feed-buffer composition. A shallow gradient reduction in denaturant concentration of the feed stream over 30 min maintained the stability of the expanded bed during adsorptive refolding. In a separate experiment, buoyancy-induced mixing was completely avoided by performing refolding in a settled bed, which achieved comparable yields to refolding in an expanded bed but required a slightly more complex process. A total of 10% of the available KSI,(His6) was recovered as biologically active and purified protein using the described purification and refolding process, and the yield was further increased to 19% by performing a second iteration of the on-column refolding operation. This process should be applicable for other polyhistidine tagged proteins and is likely to have the greatest benefit for proteins that tend to aggregate when refolded by dilution. [source] Estimation of endogenous adenosine activity at adenosine receptors in guinea-pig ileum using a new pharmacological methodACTA PHYSIOLOGICA, Issue 2 2010K. F. Nilsson Abstract Aim:, Adenosine modulates neurotransmission and in the intestine adenosine is continuously released both from nerves and from smooth muscle. The main effect is modulation of contractile activity by inhibition of neurotransmitter release and by direct smooth muscle relaxation. Estimation of adenosine concentration at the receptors is difficult due to metabolic inactivation. We hypothesized that endogenous adenosine concentrations can be calculated by using adenosine receptor antagonist and agonist and dose ratio (DR) equations. Methods:, Plexus-containing guinea-pig ileum longitudinal smooth muscle preparations were made to contract intermittently by electrical field stimulation in organ baths. Schild plot regressions were constructed with 2-chloroadenosine (agonist) and 8-(p -sulfophenyl)theophylline (8-PST; antagonist). In separate experiments the reversing or enhancing effect of 8-PST and the inhibiting effect of 2-chloroadenosine (CADO) were analysed in the absence or presence of an adenosine uptake inhibitor (dilazep), and nucleoside overflow was measured by HPLC. Results:, Using the obtained DR, baseline adenosine concentration was calculated to 28 nm expressed as CADO activity, which increased dose dependently after addition of 10,6 m dilazep to 150 nm (P < 0.05). HPLC measurements yielded a lower fractional increment (80%) in adenosine during dilazep, than found in the pharmacological determination (440%). Conclusion:, Endogenous adenosine is an important modulator of intestinal neuro-effector activity, operating in the linear part of the dose,response curve. Other adenosine-like agonists might contribute to neuromodulation and the derived formulas can be used to calculate endogenous agonist activity, which is markedly affected by nucleoside uptake inhibition. The method described should be suitable for other endogenous signalling molecules in many biological systems. [source] How psychiatrists inform themselves and their patients about risks and benefits of antipsychotic treatmentACTA PSYCHIATRICA SCANDINAVICA, Issue 2 2009R. Mendel Objective:, In order to choose the best treatment option, physicians have to inform themselves and their patients about both the benefits and risks of available treatment options equally. Our study aims to investigate whether psychiatrists actually do conduct such a balanced information search and presentation. Method:, Psychiatrists' information search and information presentation to a patient with schizophrenia were studied using two separate experiments. In both, participants were presented with hypothetical case vignettes and descriptions of fictitious antipsychotics. Results:, When searching for information, psychiatrists looked more for risks than benefits of antipsychotic treatment options (t = ,3.4, df = 74, P = 0.001). However, when informing a patient, they named more benefits than risks (t = 17.1, df = 224, P < 0.001). Conclusion:, The risk-biased information search presumably follows the principle of ,primum non nocere'. The benefit-biased information presentation might be motivated by the wish to persuade patients to accept the proposed therapy. [source] Genetic analysis of larval survival and larval growth of two populations of Leptinotarsa decemlineata on tomatoENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 2 2001Wenhua Lu Abstract The genetics of adaptation to tomato in Leptinotarsa decemlineata (Say) were investigated in reciprocal F1, F2, and backcross populations generated from crosses between beetles from a tomato adapted population and from a population that was poorly adapted to tomato. Larvae from the parent and test populations were reared on tomato for four days, after which survivorship and larval weights were recorded. Most results indicate that differences in larval growth and survival on tomato between the parent populations are largely determined by autosomal, polygenic mechanisms, the inheritance of which involves a significant dominance component. However, results from F2 crosses are not consistent with this conclusion. A significant difference in larval weights, but not in survival, between reciprocal F1 populations in an analysis of combined data from four separate experiments suggests that maternal cytoplasmic effects may contribute to differences in larval performance on tomato between the adapted and unadapted populations. The unusual results obtained from F2 crosses in this study are not atypical of results from previous studies of the genetics of adaptation to host plants by the Colorado potato beetle. Host plant adaptation by Colorado potato beetles may therefore involve unusual genetic mechanisms that are not easily assessed by classical Mendelian analysis. [source] Effects of 17 ,-estradiol exposure on Xenopus laevis gonadal histopathologyENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 5 2010Jeffrey C. Wolf Abstract The natural estrogen 17 ,-estradiol (E2) is a potential environmental contaminant commonly employed as a positive control substance in bioassays involving estrogenic effects. The aquatic anuran Xenopus laevis is a frequent subject of reproductive endocrine disruptor research; however, histopathological investigations have tended to be less than comprehensive. Consequently, a study was designed to characterize gross and microscopic changes in the gonads of X. laevis as a result of E2 exposure. Additional goals of this study, which consisted of three separate experiments, included the standardization of diagnostic terminology and criteria, the validation of statistical methodology, and the establishment of a half maximal effective concentration (EC50) for E2 as defined by an approximately 50% conversion of presumptive genotypic males to phenotypic females. In the first experiment, frogs were exposed to nominal concentrations of 0, 0.2, 1.5, or 6.0,µg/L E2. From these experimental results and those of a subsequent range finding trial, the EC50 for E2 was determined to be approximately 0.2,µg/L. This E2 concentration was utilized in the other two experiments, which were performed at different facilities to confirm the reproducibility of results. Experiments were conducted according to Good Laboratory Practice guidelines, and the histopathologic evaluations were peer reviewed by an independent pathologist. Among the three trials, the histopathological findings that were strongly associated with E2-exposure (p,<,0.001 to 0.0001) included an increase in the proportion of phenotypic females, mixed sex, dilated testis tubules, dividing gonocytes in the testis, and dilated ovarian cavities in phenotypic ovaries. A comparison of the gross and microscopic evaluations suggested that some morphologic changes in the gonads may potentially be missed if studies rely entirely on macroscopic assessment. Environ. Toxicol. Chem. 2010;29:1091,1105. © 2010 SETAC [source] Dynamics of 17,-Ethynylestradiol exposure in rainbow trout (Oncorhynchus mykiss): Absorption, tissue distribution, and hepatic gene expression patternENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 11 2006Ann D. Skillman Abstract 17,-Ethynylestradiol (EE2) is a synthetic estrogen identified in sewage effluents. To understand better the absorption kinetics of EE2 and the induction of vitellogenin (VTG) and estrogen receptor , (ER,) mRNA, we subjected male rainbow trout (Onchorynchus mykiss) to continuous water exposures of 125 ng/L of EE2 for up to 61 d. Trout were either repetitively sampled for blood plasma or serially killed at selected time intervals. Vitellogenin, ER, mRNA, and EE2 were measured using enzymelinked immunosorbent assay and using quantitative polymerase chain reaction and gas chromatography,mass spectrometry, respectively. In separate experiments, trout were exposed to EE2 for 7 d, and hepatic gene expression was assessed using a low- and high-density cDNA microarray. The EE2 was rapidly absorbed by the trout, with an apparent equilibrium at 16 h in plasma and liver. The ER, mRNA levels also increased rapidly, reaching near-peak levels by 48 h. In contrast, plasma levels of VTG continuously increased for 19 d. After 61 d, tissues with the highest levels of VTG were the liver, kidney, and testes. Microarray-based gene expression studies provided unexpected results. In some cases, known estrogen-responsive genes (e.g., ER,) were unresponsive, whereas many of the genes that have no apparent link to estrogen function or EE2 toxicity were significantly altered in expression. Of the two microarray approaches tested in the present study, the high-density array appeared to be superior because of the improved quality of the hybridization signal and the robustness of the response in terms of the number of genes identified as being EE2 responsive. [source] Bradykinin stimulates prostaglandin E2 production and cyclooxygenase activity in equine nonglandular and glandular gastric mucosa in vitroEQUINE VETERINARY JOURNAL, Issue 4 2008N. K. MORRISSEY Summary Reasons for performing study: There are few data available regarding regulation of prostaglandin (PG) generation by equine gastric mucosae and the role of the cyclooxygenase (COX) isoforms in their production. Objectives: To: 1) characterise and quantify PGE2 output in vitro; 2) examine the sensitivity of PGE2 production to exogenous bradykinin (BK) exposure; 3) determine the contribution of the COX-1 and COX-2 pathways to basal and BK-stimulated PGE2 production; and 4) measure if BK influences electrogenic ion transport in equine gastric mucosae in vitro. Methods: Full thickness gastric sheets were obtained from horses at post mortem, stripped of muscle layers and mounted in Ussing chambers. Tissues were exposed to bradykinin (BK, 0.1 ,mol/l) either alone, or following pretreatment with a selective COX-2 inhibitor (NS-398, 1 ,mol/l) or a nonselective COX inhibitor (piroxicam, 1 ,mol/l), or were untreated. Results: BK administration increased PGE2 output from the basolateral but not the apical faces of both tissue types. Piroxicam, but not NS-398, reduced basolateral PGE2 release below control levels in both tissue types. Both piroxicam and NS-398 pretreatment inhibited BK-stimulated PGE2 release. In separate experiments, BK was without effect upon electrophysiological parameters of tissues mounted in Ussing chambers. Conclusions: PGE2 is produced by the nonglandular and glandular equine gastric mucosae in vitro. Significantly more PGE2 is released basolaterally than apically. BK stimulated the production of PGE2 from the basolateral side of both tissue types. These findings suggest that COX-1 is a significant pathway for basal PGE2 production from the basolateral faces of both nonglandular and glandular equine gastric mucosae in vitro. Potential relevance: The identification of the cells responsible for basolateral PGE2 release, via both COX-1 and COX-2 pathways, under basal and BK-stimulated conditions requires further study. [source] Bidirectional modulation of visual plasticity by cholinergic receptor subtypes in the frog optic tectumEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 6 2003Chuan-Jiang Yu Abstract Cholinergic input to the optic tectum is necessary for visual map maintenance. To understand why, we examined the effects of activation of the different cholinergic receptor subtypes in tectal brain slices and determined whether the retinotectal map was affected by manipulations of their activity in vivo. Both ,-bungarotoxin sensitive and insensitive nicotinic receptor agonists increased spontaneous postsynaptic currents (sPSCs) in a subpopulation of patch-clamped tectal cells; application of subtype selective receptor antagonists reduced nicotine-induced increases in sPSCs. Activation of ,-bungarotoxin insensitive nicotinic receptors also induced substantial inward current in some cells. Muscarinic receptor mediated outward current responses were blocked by the M2-like muscarinic receptor antagonists himbacine or AF-DX 384 and mimicked by application of the M2-like agonist oxotremorine. A less frequently observed muscarinic response involving a change in sPSC frequency appeared to be mediated by M1-like muscarinic receptors. In separate experiments, pharmacological manipulation of cholinergic receptor subtype activation led to changes in the activity-dependent visual map created in the tectum by retinal ganglion cell terminals. Chronic exposure of the tectum to either ,-bungarotoxin insensitive, ,-bungarotoxin sensitive or M1-like receptor antagonists resulted in map disruption. However, treatment with the M2-like receptor antagonist, AF-DX 384, compressed the map. We conclude that nicotinic or M1-like muscarinic receptors control input to tectal cells while ,-bungarotoxin insensitive nicotinic receptors and M2-like muscarinic receptors change tectal cell responses to that input. Blockade of the different cholinergic receptor subtypes can have opposing effects on map topography that are consistent with expected effects on tectal cell activity levels. [source] Differential modulation of AMPA receptors by cyclothiazide in two types of striatal neuronsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2000Vladimir S. Vorobjev Abstract The modulation of ,-amino-3-hydroxy-5-methyl-4-isoxazol-propionate (AMPA) receptor-mediated currents by cyclothiazide was investigated in acutely isolated cells from rat striatum with whole-cell patch-clamp recording. Single-cell reverse transcriptase-polymerase chain reaction (RT-PCR) was used to identify medium spiny and giant aspiny neurons and to determine their AMPA receptor subunit composition mostly in separate experiments. After pretreatment with cyclothiazide, kainate-induced AMPA responses were more strongly potentiated in medium spiny than in giant aspiny neurons; cyclothiazide induced a ninefold leftward shift in the kainate concentration,response curve for medium spiny neurons (not giant aspiny neurons). The EC50s for the cyclothiazide potentiation did not differ substantially between medium spiny neurons and giant aspiny neurons. The recovery of kainate-activated currents from modulation by cyclothiazide was slower for medium spiny neurons than for giant aspiny neurons. Medium spiny neurons expressed GluR-A, GluR-B and GluR-C, but not GluR-D subunits in both flip and flop splice variants. All giant aspiny neurons expressed GluR-A and GluR-D, exclusively in the flop form, half of them also expressed GluR-B and GluR-C. This is in keeping with slow and fast desensitization kinetics in medium spiny neurons and giant aspiny neurons, respectively, and differences in cyclothiazide modulation. The rate of cyclothiazide dissociation from the AMPA receptor, activated by glutamate, was ,,90 times slower in medium spiny neurons than in giant aspiny neurons. In giant aspiny neurons (not medium spiny neurons) this rate was strongly dependent on the presence of an agonist; 1 m m glutamate increased it 30-fold. Thus, two major cell groups in the striatum display distinct AMPA receptor compositions carrying specific properties of glutamate responses. Excitatory transmission will thus be differentially affected by cyclothiazide-type compounds. [source] Relationship between the isotopically exchangeable and resin-extractable phosphate of deficient to heavily fertilized soilEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 4 2000A. Schneider Summary The rate and extent of soil,solution transfer of orthophosphate ions (Pi) depend both on soil solution Pi concentration and on time. This is so both in experiments on sorption,desorption and in those on isotopic exchange. Because the two methods are based on different principles, it is questionable whether they give a similar quantification of Pi transfer. The amount of isotopically exchangeable Pi, E, was determined over periods of 100 minutes and described as a function of both time and Pi concentration in solution for three soil samples taken from field plots having different P fertilizer histories over 26 years of annual application. In separate experiments, amounts of Pi, Qd, were extracted from soil suspensions using three levels of anion exchange resin strips for periods ranging from 10 minutes to 7 days. Both initial and final solution Pi concentrations were measured. These concentrations and periods of resin-contact were used to predict the difference in E, ,E, between the initial and final states of the suspension,resin system using extrapolations of the equations fitted to the exchange data. Under conditions in which the solution concentration of Pi decreased during extraction the ,E values and the resin-extracted Pi values, Qd, were equal. It is thus possible, using the description of E, to predict the amount of Pi released from soil suspension knowing the initial and final solution Pi concentrations and the time it took for the system to pass from the initial to the final state. For the soil studied, identical amounts of mobile Pi, i.e. the Pi which participates in the soil,solution dynamics, may therefore be assessed by either isotopic exchange or desorption. [source] CHARACTER DISPLACEMENT IN POLYPHENIC TADPOLESEVOLUTION, Issue 5 2000David W. Pfennig Abstract Biologists have long known that closely related species are often phenotypically different where they occur together, but are indistinguishable where they occur alone. The causes of such character displacement are controversial, however. We used polyphenic spadefoot toad tadpoles (Spea bombifrons and S. multiplicata) to test the hypothesis that character displacement evolves to minimize competition for food. We also sought to evaluate the role of phenotypic plasticity in the mediation of competitive interactions between these species. Depending on their diet, individuals of both species develop into either a small-headed omnivore morph, which feeds mostly on detritus, or a large-headed carnivore morph, which specializes on shrimp. Laboratory experiments and surveys of natural ponds revealed that the two species were more dissimilar in their tendency to produce carnivores when they occurred together than when they occurred alone. This divergence in carnivore production was expressed as both character displacement (where S. multiplicata's propensity to produce carnivores was lower in sympatry than in allopatry) and as phenotypic plasticity (where S. multiplicata facultatively enhanced carnivore production in S. bombifrons, and S. bombifrons facultatively suppressed carnivore production in S. multiplicata). In separate experiments, we established that S. bombifrons (the species for which carnivore production was enhanced) was the superior competitor for shrimp. Conversely, S. multiplicata (the species for which carnivore production was suppressed and omnivore production enhanced) was the superior competitor for detritus. These results therefore demonstrate that selection to minimize competition for food can cause character displacement. They also suggest that both character displacement and phenotypic plasticity may mediate competitive interactions between species. [source] | ||||||||||||||||||||||||||||||||||