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Pressure Threshold (pressure + threshold)
Selected AbstractsDay-to-day reproducibility of anorectal sensorimotor assessments in healthy subjectsNEUROGASTROENTEROLOGY & MOTILITY, Issue 2 2004A. E. Bharucha Abstract, The reproducibility of tests widely utilized to assess anorectal sensorimotor functions is not well established. Our aims were to assess the intra-individual day-to-day reproducibility of these parameters in healthy subjects. Anal sphincter pressures were assessed by perfusion manometry on two separate days in 19 healthy subjects. Rectal pressure,volume (p,v) curves and sensory thresholds were assessed in 12/19 subjects by inflating a highly compliant polyethylene balloon from 0 to 32 mmHg in 4 mmHg steps. Subjects also rated intensity of perception by visual analogue scale (VAS) during phasic distentions 8, 16 and 24 mmHg above operating pressure, in randomized sequence. Resting and squeeze anal pressures and rectal compliance were highly reproducible (rs , 0.7) in the same subject on separate days. Pressure thresholds for urgency appeared less reproducible than thresholds for initial perception and the desire to defecate. VAS scores were highly reproducible only during the 24-mmHg distention. Thus, anal pressures and rectal compliance are highly reproducible within healthy subjects on separate days, while sensory thresholds are reproducible to a variable degree, dependent on the intensity of stimulation and the perception being assessed. [source] Inflammatory Pain Reduction In Rats By Local Treatment With oATP, A Selective Inhibitor Of P2X7 ATP ReceptorJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 1 2001G Dell'Antonio Peptide neurotransmitters, as substance P or ATP, are released during inflammatiory processes by the nerve endings of sensory fibers. ATP is also released from the cytoplasm of damaged cells at the site of inflammation. It acts at the level of many P2X subtypes of purinoreceptors. The receptor for extracellular ATP named P2Z/P2X7 is selectively blocked by the periodate oxidized ATP (oATP). We have hypothesized that P2X subunits present on peripheral sensory nerve terminals, able to initiate a nociceptive signal, could be blocked by local treatment with oATP, so inducing pain relief. Male inbred Fisher rats weighing about 250 g were used. Unilateral inflammation into rat hind paw was induced by intraplantar injection of Freund's complete adjuvant (FCA). The following signs of inflammation, from 3 to 48 h after FCA injection, were detected: increased paw volume, increased paw temperature and hyperalgesia. The latter was evaluated using an algesiometric test wich measured the paw pressure threshold (PPT, expressed in g). We treated some rats, bearing paw inflammation by 12 h, with local injection of 56 ,M oATP. We showed a significant reduction of hyperalgesia in treated rats (PPT = 190 ± 2.3 in inflamed paw of oATP treated vs. PPT = 60 ± 1.6 in inflamed paw of untreated rats, at 60 min following oATP innoculation). We showed also that treatment with oATP was more efficient than treatment with diclofenac in reducing local inflammatory pain (PPT expressed as percentage of the maximum possible effect = 60 ± 0.5, at 120 min following intraplantar administration of oATP, vs. 25 ± 1.9 at the same time following intraplantar administration of diclofenac). The use of polyclonal antibody anti P2X7 receptor to perform immunohistochemical analysis of inflamed tissue, showed a reduction of receptor expression at the level of nerve endings in sections obtained from rat paw treated with oATP with respect to sections obtained from untreated rats. Such an effect was independent on the recruitment of immunocytes in inflamed tissue. Our results demonstrate that ATP exerts a key role in the pathophysiology of peripheral inflammation and that oATP may be effective in treating inflammatory pain. [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] SURVEY OF MANAGEMENT OF ACUTE, TRAUMATIC COMPARTMENT SYNDROME OF THE LEG IN AUSTRALIAANZ JOURNAL OF SURGERY, Issue 9 2007Christopher J. Wall Background: Acute compartment syndrome is a serious and not uncommon complication of limb trauma. The condition is a surgical emergency and is associated with significant morbidity if not diagnosed promptly and treated effectively. Despite the urgency of effective management to minimize the risk of adverse outcomes, there is currently little consensus in the published reports as to what constitutes best practice in the management of acute limb compartment syndrome. Methods: A structured survey was sent to all currently practising orthopaedic surgeons and accredited orthopaedic registrars in Australia to assess their current practice in the management of acute, traumatic compartment syndrome of the leg. Questions were related to key decision nodes in the management process, as identified in a literature review. These included identification of patients at high risk, diagnosis of the condition in alert and unconscious patients, optimal timeframe and technique for carrying out a fasciotomy and management of fasciotomy wounds. Results: A total of 264 valid responses were received, a response rate of 29% of all eligible respondents. The results indicated considerable variation in management of acute compartment syndrome of the leg, in particular in the utilization of compartment pressure measurement and the appropriate pressure threshold for fasciotomy. Of the 78% of respondents who regularly measured compartment pressure, 33% used an absolute pressure threshold, 28% used a differential pressure threshold and 39% took both into consideration. Conclusions: There is variation in the management of acute, traumatic compartment syndrome of the leg in Australia. The development of evidence-based clinical practice guidelines may be beneficial. [source] Cerebral white matter blood flow and arterial blood pressure in preterm infantsACTA PAEDIATRICA, Issue 10 2010Klaus Børch Abstract It is generally assumed that one reason why white matter injury is common in preterm infants is the relatively poor vascular supply. Aim:, To examine whether blood flow to the white matter is relatively more reduced at low blood pressure than is blood flow to the brain as a whole. Methods:, Thirteen normoxic preterm infants had blood flow imaging on 16 occasions with single-photon emission computed tomography (SPECT) using 99Tc labelled hexa-methylpropylenamide oxime (HMPAO) as the tracer. Gestational age was 26,32 weeks. Transcutaneous carbon dioxide was between 4.7 and 8.5 kPa and mean arterial blood pressure between 22 and 55 mmHg. Results:, There was no statistically significant direct relation between white matter blood flow percentage and any of the variables. Using non-linear regression, however, assuming a plateau over a certain blood pressure threshold and a positive slope below this threshold, the relation to white matter flow percentage was statistically significant (p = 0.02). The threshold was 29 mmHg (95% confidence limits 26,33). Conclusion:, Our analysis supports the concept of periventricular white matter as selectively vulnerable to ischaemia during episodes of low blood pressure. [source] Lactobacillus reuteri ingestion and IKCa channel blockade have similar effects on rat colon motility and myenteric neuronesNEUROGASTROENTEROLOGY & MOTILITY, Issue 1 2010B. Wang Abstract, Background, We have previously shown that ingestion of Lactobacillus reuteri may modulate colonic enteric neuron activity but with unknown effects on colon motility. The aim of the present report was to elucidate the neuronal mechanisms of action of the probiotic by comparing the effects on motility of L. reuteri ingestion with blockade of a specific ionic current in enteric neurons. Methods, We have used intraluminal pressure recordings from ex vivo rat colon segments and whole cell patch clamp recordings from neurons of rat longitudinal muscle myenteric plexus preparations to investigate the effects of L. reuteri and TRAM-34 on colon motility and neurophysiology. The effects of daily feeding of 109L. reuteri bacteria or acute application of TRAM-34 on threshold fluid filling pressure or pulse pressure was measured. Key Results,Lactobacillus reuteri increased intraluminal fluid filling pressure thresholds for evoking pressure pulses by 51% from 0.47 ± 0.17 hPa; the probiotic also decreased the pulse pressure amplitudes, but not frequency, by 18% from 3.91 ± 0.52 hPa. The intermediate conductance calcium-dependent potassium (IKCa) channel blocker TRAM-34 (3 ,mol L,1) increased filling threshold pressure by 43% from 0.52 ± 0.22 hPa and reduced pulse pressure amplitude by 40% from 2.63 ± 1.11 hPa; contraction frequency was unaltered. TRAM-34 (3 ,mol L,1) reduced membrane polarization, leak conductance and the slow afterhyperpolarization current in 16/16 myenteric rat colon AH cells but 19/19 S cells were unaffected. Conclusions & Inferences, The present results are consistent with L. reuteri enhancing tonic inhibition of colon contractile activity by acting via the IKCa channel current in AH cells. [source] Touch sensitivity with sterile standard surgical gloves and single-use protective glovesANAESTHESIA, Issue 10 2006W. Tiefenthaler The purpose of this study was to evaluate touch sensitivity and static two-point discrimination of the dominant index and middle finger in 20 anaesthetists wearing no gloves, single-use protective gloves or sterile standard surgical gloves. Semmes-Weinstein filaments were used to measure cutaneous pressure thresholds, and a Two-Point-Discriminator to estimate static two-point discrimination. Wearing gloves significantly reduced touch sensitivity (p < 0.01), but not two-point discrimination. No difference in touch sensitivity or two-point discrimination was found between different types of gloves. The results of our study suggest that the additional cost of sterile standard surgical gloves can not be justified in terms of touch sensitivity. [source] | ||||||||||