JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 5 2003
Article first published online: 29 APR 200
No abstract is available for this article. [source]

Gene expression changes in human cells after exposure to mobile phone microwaves

PROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 17 2006
Daniel Remondini
Abstract Possible biological effects of mobile phone microwaves were investigated in,vitro. In this study, which was part of the 5FP EU project REFLEX (Risk Evaluation of Potential Environmental Hazards From Low-Energy Electromagnetic Field Exposure Using Sensitive in,vitro Methods), six human cell types, immortalized cell lines and primary cells, were exposed to 900 and 1800,MHz. RNA was isolated from exposed and sham-exposed cells and labeled for transcriptome analysis on whole-genome cDNA arrays. The results were evaluated statistically using bioinformatics techniques and examined for biological relevance with the help of different databases. NB69 neuroblastoma cells, T,lymphocytes, and CHME5 microglial cells did not show significant changes in gene expression. In EA.hy926 endothelial cells, U937,lymphoblastoma cells, and HL-60 leukemia cells we found between 12 and 34,up- or down-regulated genes. Analysis of the affected gene families does not point towards a stress response. However, following microwave exposure, some but not all human cells might react with an increase in expression of genes encoding ribosomal proteins and therefore up-regulating the cellular metabolism. [source]

Rituximab for rheumatoid arthritis refractory to anti,tumor necrosis factor therapy: Results of a multicenter, randomized, double-blind, placebo-controlled, phase III trial evaluating primary efficacy and safety at twenty-four weeks

ARTHRITIS & RHEUMATISM, Issue 9 2006
Stanley B. Cohen
Objective To determine the efficacy and safety of treatment with rituximab plus methotrexate (MTX) in patients with active rheumatoid arthritis (RA) who had an inadequate response to anti,tumor necrosis factor (anti-TNF) therapies and to explore the pharmacokinetics and pharmacodynamics of rituximab in this population. Methods We evaluated primary efficacy and safety at 24 weeks in patients enrolled in the Randomized Evaluation of Long-Term Efficacy of Rituximab in RA (REFLEX) Trial, a 2-year, multicenter, randomized, double-blind, placebo-controlled, phase III study of rituximab therapy. Patients with active RA and an inadequate response to 1 or more anti-TNF agents were randomized to receive intravenous rituximab (1 course, consisting of 2 infusions of 1,000 mg each) or placebo, both with background MTX. The primary efficacy end point was a response on the American College of Rheumatology 20% improvement criteria (ACR20) at 24 weeks. Secondary end points were responses on the ACR50 and ACR70 improvement criteria, the Disease Activity Score in 28 joints, and the European League against Rheumatism (EULAR) response criteria at 24 weeks. Additional end points included scores on the Functional Assessment of Chronic Illness Therapy,Fatigue (FACIT-F), Health Assessment Questionnaire (HAQ) Disability Index (DI), and Short Form 36 (SF-36) instruments, as well as Genant-modified Sharp radiographic scores at 24 weeks. Results Patients assigned to placebo (n = 209) and rituximab (n = 311) had active, longstanding RA. At week 24, significantly more (P < 0.0001) rituximab-treated patients than placebo-treated patients demonstrated ACR20 (51% versus 18%), ACR50 (27% versus 5%), and ACR70 (12% versus 1%) responses and moderate-to-good EULAR responses (65% versus 22%). All ACR response parameters were significantly improved in rituximab-treated patients, who also had clinically meaningful improvements in fatigue, disability, and health-related quality of life (demonstrated by FACIT-F, HAQ DI, and SF-36 scores, respectively) and showed a trend toward less progression in radiographic end points. Rituximab depleted peripheral CD20+ B cells, but the mean immunoglobulin levels (IgG, IgM, and IgA) remained within normal ranges. Most adverse events occurred with the first rituximab infusion and were of mild-to-moderate severity. The rate of serious infections was 5.2 per 100 patient-years in the rituximab group and 3.7 per 100 patient-years in the placebo group. Conclusion At 24 weeks, a single course of rituximab with concomitant MTX therapy provided significant and clinically meaningful improvements in disease activity in patients with active, longstanding RA who had an inadequate response to 1 or more anti-TNF therapies. [source]

Prevalence of persistent primary reflexes and motor problems in children with reading difficulties

DYSLEXIA, Issue 4 2004
M. McPhillips
Abstract It has been shown that some children with reading difficulties have underlying developmental delay and that this may be related to the persistence of primary reflexes. This study investigated the prevalence of persistent primary reflexes in the ordinary primary school population and how this related to other cognitive and social factors. Three groups of 41 children were drawn from a representative, cross-sectional sample of 409 children (aged 9,10 years) attending 11 ordinary primary schools in N. Ireland. The three groups represented the bottom, middle and top 10% respectively of readers from the total sample population. The relative persistence (on a scale of 0 to 4) of the Asymmetrical Tonic Neck Reflex (ATNR) and the prevalence of motor difficulties were assessed for these 3 groups. The rôle of 5 predictor variables (verbal IQ, social deprivation, sex, month of birth and religious affiliation) in determining the reading level of the total sample was also investigated. It was found that the lowest reading group had a significantly higher mean level of ATNR (1.56 [95% CI 1.22,1.90]) compared with the middle reading group (0.56 [0.22,0.90]) and the top reading group (0.59 [0.25,0.92]). 17% of children in the lowest reading group had extremely high levels of the ATNR while 24% showed no presence of ATNR. This contrasted with 0% and 66%, respectively for both middle and top reading groups. It was also found that there was a significant difference between the lowest reading group and the top reading group on a standardised test of motor ability. Furthermore, there was evidence that ATNR persistence but not motor ability was associated with the sex of the child with boys, in particular, at risk. There was no evidence that ATNR persistence or motor ability was significantly associated with social deprivation. It was also found that there were no significant differences between dyslexic and non-dyslexic children with reading difficulties in motor (including balance) performance. This study highlights the high levels of primary reflex persistence in children with reading difficulties and it provides further evidence of the association between reading difficulties and movement difficulties in young children. However, while the implications for intervention are discussed, it is stressed that the persistence of primary reflexes cannot be used as a causal model for reading difficulties, including dyslexia. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Characterization of the Vestibulo-Ocular Reflex Evoked by High-Velocity Movements

THE LARYNGOSCOPE, Issue 7 2004
François D. Roy HBSc
Abstract Objectives/Hypothesis: The horizontal angular vestibulo-ocular reflex (VOR) plays an important role in stabilizing images on the retina throughout head rotations. Current evidence suggests that the VOR behaves linearly at low velocities and nonlinearly at high velocities. The aim of the research was to evaluate and characterize the normal behavior of the reflex evoked by high-velocity head rotations. Study Design: Case control study. Methods: Manually applied head-thrust movements with peak velocities in the range of 100° to 500°/s and peak accelerations up to 7,000°/s 2 were performed on normal volunteers. These head thrusts were comparable with those described in detail by Halmagi and coworkers. Eye and head movements were recorded using the magnetic search coil method. Results: The gain of the VOR is linear at low velocities and saturates at head velocities greater than 350°/s. The values for the normal gain of the reflex were approximated by means of the area between two nonlinear functions. The directional difference parameter, exploring the symmetry of the reflex, indicated that the VOR in normal subjects is symmetric. Conclusion: The gain of the VOR in individuals with intact vestibular function is nonlinear at high angular head velocities. We propose a quantitative means using two nonlinear functions to characterize the normal range of values for the gain of the VOR in individuals with normal vestibular function. A directional difference parameter used in conjunction with the normal range of gains can detect small differences in the symmetry of the VOR and, consequently, reveal unilateral vestibular loss. [source]

Deterioration of the Pharyngo-UES Contractile Reflex in the Elderly ,

THE LARYNGOSCOPE, Issue 9 2000
Junlong Ren MD
Abstract Objectives/Hypothesis Deterioration of aerodigestive tract reflexes such as the esophagoglottal and pharyngoglottal closure reflexes and pharyngeal swallow has been documented in the elderly. However, the effect of aging on the contractile response of the upper esophageal sphincter (UES) to pharyngeal water stimulation has not been studied. The aim of this study was to characterize the pharyngo-UES reflex in the healthy elderly. Methods We studied nine healthy elderly (77 ± 1 y [SD]; four men, five women) and nine healthy young volunteers (26 ± 2 y [SD]; four men, five women). A UES sleeve sensor was used to measure the pressure. We tested pharyngeal stimulation induced by rapid pulse and slow continuous injection of water. Results The volume of water required to stimulate the pharyngo-UES contractile reflex by rapid pulse injection in the elderly (0.5 ± 34 0.1 mL) was significantly higher than that in the young (0.1 ± 0.02 mL) (P < .05). In contrast to young subjects, there was no pressure increase in resting UES pressure observed in the elderly for continuous pharyngeal water infusion. In both young and elderly, the threshold volume for the pharyngo-UES contractile reflex was significantly lower than that for pharyngeal swallows. Conclusions The pharyngo-UES contractile reflex deteriorates with aging. This deterioration is primarily due to abnormalities of the afferent limb of the reflex. [source]

Role of Vascular Reflex in Nasal Mucosal Swelling in Nasal Allergy

THE LARYNGOSCOPE, Issue 2 2000
Tsutomu Numata MD
Abstract Objective: In patients with nasal allergy, antigen challenge on the unilateral nasal mucosa results in nasal secretion not only in the ipsilateral but also in the contralateral nasal cavities that can be inhibited almost completely by premedication with atropine sulfate. The present study was performed to elucidate if centrally mediated vascular reflex induced by antigen challenge plays a role in nasal mucosal swelling in subjects with nasal allergy. Methods: Variations of mucosal swelling and mucosal blood flow in the ipsilateral and the contralateral nasal cavities after unilateral antigen challenge were evaluated by acoustic rhinometry and laser Doppler flowmetry in 20 patients with perennial nasal allergy. Results: Unilateral antigen challenge caused ipsilateral and contralateral nasal mucosal swelling in 17 and 13 patients, respectively. Incidence of contralateral nasal mucosal swelling after unilateral antigen challenge was significantly higher compared with that after control disc challenge (P < .001). In 10 patients in whom unilateral antigen challenge caused bilateral nasal mucosal swelling, significant swelling of the nasal mucosa lasted for more than 30 minutes in the ipsilateral nasal cavity after antigen challenge compared with only 15 minutes in the contralateral nasal cavity. Peak values of contralateral mucosal swelling were 45.3% of those of ipsilateral nasal mucosa. Conclusions: Centrally mediated vascular reflex is partially involved in the onset of nasal mucosal swelling observed after antigen challenge in subjects with nasal allergy. However, nasal mucosal swelling that persists and proceeds even 20 minutes after antigen challenge is caused by the direct effects of chemical mediators on the nasal vasculature. [source]

Effect of vitamin E supplementation in patients with ataxia with vitamin E deficiency

EUROPEAN JOURNAL OF NEUROLOGY, Issue 5 2001
S. Gabsi
Ataxia with vitamin E (Vit E) defciency (AVED) is an autosomal recessive disorder caused by mutations of the , tocopherol transfer protein gene. The Friedreich ataxia phenotype is the most frequent clinical presentation. In AVED patients, serum Vit E levels are very low in the absence of intestinal malabsorption. As Vit E is a major antioxidant agent, Vit E deficiency is supposed to be responsible for the pathological process. Twenty-four AVED patients were fully investigated (electromyography, nerve conduction velocity (NVC) studies, somatosensory evoked potentials, cerebral computed tomography scan, sural nerve biopsy, genetic studies) and supplemented with Vit E (800 mg daily) during a 1-year period. Clinical evaluation was mainly based on the Ataxia Rating Scale (ARS) for cerebellar ataxia assessment and serum Vit E levels were monitored. Serum Vit E levels normalized and ARS scores decreased moderately but significantly suggesting clinical improvement. Better results were noted with mean disease duration , 15 years. Reflexes remained abolished and posterior column disturbances unchanged. Vitamin E supplementation in AVED patients stabilizes the neurological signs and can lead to mild improvement of cerebellar ataxia, especially in early stages of the disease. [source]

Cardiac Reflexes During Pacing: Are We Getting to the Heart of the Matter?

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 5 2006
CARLOS A. MORILLO M.D., F.A.C.C., F.R.C.P.C.
[source]

Modulation of spinal reflexes by aversive and sexually appetitive stimuli

PSYCHOPHYSIOLOGY, Issue 2 2003
Stephanie Both
Abstract In this study, modulation of spinal tendinous (T) reflexes by sexual stimulation was investigated. T reflexes are augmented in states of appetitive and defensive action and modified by differences in arousal intensity. Reflexes were expected to be facilitated by both pleasant (sexual) and unpleasant (anxiety) stimuli. Subjects were exposed to a sexual, an anxiety-inducing, a sexually threatening, and a neutral film excerpt. Genital arousal, emotional experience, subjective action tendencies, and T reflexes were monitored. Self-report and genital data confirmed the affective states as intended. T reflex amplitude significantly increased during viewing of emotionally arousing film excerpts as compared with a neutral film excerpt. T reflexes were facilitated by the sex stimulus to the same extent as by the anxiety and sexual threat stimuli. The results support the view of sexual arousal as an emotional state, generating sex-specific autonomic and general somatic motor system responses, which prepare the organism for action. [source]

ORIGINAL RESEARCH,BASIC SCIENCE: Effect of the Destruction of Cells Containing the Serotonin Reuptake Transporter on Urethrogenital Reflexes

THE JOURNAL OF SEXUAL MEDICINE, Issue 2 2007
Karla Gravitt BSc
ABSTRACT Introduction., The urethrogenital (UG) reflex is an autonomic and somatic response that mimics some of the physiological changes seen during ejaculation. The UG reflex is tonically inhibited by neurons in the ventral medulla, an area containing serotonin neurons. Aim., To examine the effect of lesions of brain neurons containing the serotonin reuptake transporter (SERT) on ejaculatory-like reflexes. Methods., Anti-SERT saporin (80 nL, 1 mM) or saline was injected bilaterally into the ventrolateral medulla of male Sprague,Dawley rats. Ten to 18 days later, animals were deeply anesthetized and the presence of the UG reflex was examined before and after acute spinal cord transection (T9,10). Following the experiment the presence and number of serotonin and norepinephrine containing neurons (using tryptophan hydroxylase and dopamine beta-hydroxylase, respectively) was performed. Main Outcome Measures., The UG reflex and cell counts. Results., In saline-injected controls the UG reflex was not evoked in the anesthetized, intact preparation, indicating the presence of the supraspinal inhibition, as previously reported. Injection of anti-SERT saporin into the ventrolateral medulla allowed the UG reflex to be activated in the intact preparation, thus removed the inhibition. This was associated with a decrease in the number of serotonin neurons in the ventrolateral medulla and raphe. No change in the number of noradrenergic neurons was observed. Conclusion., These studies suggest that ventral medullary neurons containing SERT are involved in the tonic inhibition of the UG reflex. Gravitt K, and Marson L. Effect of the destruction of cells containing the serotonin reuptake transporter on urethrogenital Reflexes. J Sex Med 2007;4:322,331. [source]

Muscle metaboreflex control of the circulation during exercise

ACTA PHYSIOLOGICA, Issue 4 2010
R. Boushel
Abstract This review covers the control of blood pressure, cardiac output and muscle blood flow by the muscle metaboreflex which involves chemically sensitive nerves located in muscle parenchyma activated by metabolites accumulating in the muscle during contraction. The efferent response to metaboreflex activation is an increase in sympathetic nerve activity that constricts the systemic vasculature and also evokes parallel inotropic and chronotropic effects on the heart to increase cardiac output. The metaboreflex elicits a significant blood pressure elevating response during exercise and functions to redistribute blood flow and blood volume. Regional specificity in the efferent response to the metaboreflex activated from either the leg or the arm is seen in the balance between signals for vasoconstriction to curtail blood flow and signals to increase cardiac output. The metaboreflex has dual functions. It can both elevate and decrease muscle blood flow depending on (1) the intensity and mode of contraction, (2) the limb in which the reflex is evoked, (3) the strength of the signal defined by the muscle mass, (4) the extent to which blood flow is redistributed from inactive vascular beds to increase central blood volume and (5) the extent to which cardiac output can be increased. [source]

Prostaglandin I2 sensory input into the enteric nervous system during distension-induced colonic chloride secretion in rat colon

ACTA PHYSIOLOGICA, Issue 3 2010
J. D. Schulzke
Abstract Aim:, Intestinal pressure differences or experimental distension induce ion secretion via the enteric nervous system, the sensorial origin of which is only poorly understood. This study aimed to investigate sensorial inputs and the role of afferent and interneurones in mechanically activated submucosal secretory reflex circuits. Methods:, Distension-induced rheogenic chloride secretion was measured as increase in short-circuit current 10 min after distension (,ISC10; distension parameters ± 100 ,L, 2 Hz, 20 s) in partially stripped rat distal colon in the Ussing-chamber in vitro. PGE2 and PGI2 were measured by radioimmunoassay. Results:, ,ISC10 was 2.0 ± 0.2 ,mol h,1 cm,2 and could be attenuated by lobeline, mecamylamine and dimethylphenylpiperazine, indicating an influence of nicotinergic interneurones. Additionally, a contribution of afferent neurones was indicated from the short-term potentiation of ,ISC10 by capsaicin (1 ,m). As evidence for its initial event, indomethacin (1 ,m) inhibited distension-induced secretion and the release of PGI2 was directly detected after distension. Furthermore, serotoninergic mediation was confirmed by granisetron (100 ,m) which was functionally localized distally to PGI2 in this reflex circuit, as granisetron inhibited an iloprost-induced ISC, while indomethacin did not affect serotonin-activated ion secretion. Conclusions:, Distension-induced active electrogenic chloride secretion in rat colon is mediated by a neuronal reflex circuit which includes afferent neurones and nicotinergic interneurones. It is initiated by distension-induced PGI2 release from subepithelial cells triggering this reflex via serotoninergic 5-HT3 receptor transmission. Functionally, this mechanism may help to protect against intestinal stasis but could also contribute to luminal fluid loss, e.g. during intestinal obstruction. [source]

Reactive oxygen species in rostral ventrolateral medulla modulate cardiac sympathetic afferent reflex in rats

ACTA PHYSIOLOGICA, Issue 4 2009
M.-K. Zhong
Abstract Aim:, The aim of the present study was to investigate whether reactive oxygen species (ROS) in rostral ventrolateral medulla (RVLM) modulate cardiac sympathetic afferent reflex (CSAR) and the enhanced CSAR response caused by microinjection of angiotensin II (Ang II) into the paraventricular nucleus (PVN). Methods:, Under urethane and ,-chloralose anaesthesia, renal sympathetic nerve activity (RSNA) and mean arterial pressure (MAP) were recorded in sinoaortic-denervated and cervical-vagotomized rats. The CSAR was evaluated by the RSNA response to epicardial application of capsaicin (1.0 nmol). Results:, Bilateral RVLM microinjection of tempol (a superoxide anion scavenger) or polyethylene glycol-superoxide dismutase (PEG-SOD, an analogue of endogenous superoxide dismutase) attenuated the CSAR, but did not cause significant change in baseline RSNA and MAP. NAD(P)H oxidase inhibitors apocynin or phenylarsine oxide (PAO) also showed similar effects, but SOD inhibitor diethyldithio-carbamic acid (DETC) enhanced the CSAR and baseline RSNA, and increased the baseline MAP. Bilateral PVN microinjection of Ang II (0.3 nmol) enhanced the CSAR and increased RSNA and MAP, which was inhibited by the pre-treatment with RVLM administration of tempol, PEG-SOD, apocynin or PAO. The pre-treatment with DETC in the RVLM only showed a tendency in potentiating the CSAR response of Ang II in the PVN, but significantly potentiated the RSNA and MAP responses of Ang II. Conclusion:, These results suggest that the NAD(P)H oxidase-derived ROS in the RVLM modulate the CSAR. The ROS in the RVLM is necessary for the enhanced CSAR response caused by Ang II in the PVN. [source]

B2 kinin receptors mediate the Indian red scorpion venom-induced augmentation of visceral reflexes via the nitric oxide cyclic guanosine monophosphate pathway

ACTA PHYSIOLOGICA, Issue 4 2009
S. Kanoo
Abstract Aim:, This study was performed to delineate the kinin (receptor)-dependent pathways in the Indian red scorpion (Mesobuthus tamulus; MBT) venom-induced pulmonary oedema as well as the augmentation of cardio-pulmonary reflexes evoked by phenyldiguanide (PDG). Methods:, In urethane-anaesthetized adult rats, the effect of venom on the PDG reflex responses (blood pressure, heart rate and respiration rate) and the pulmonary water content was ascertained using various antagonists(des- Arg, B1 receptor antagonist; Hoe 140, B2 receptor antagonist; N, -nitro- l -arginine methyl ester (l -NAME), nitric oxide (NO) synthase inhibitor; methylene blue, soluble guanylate cyclase inhibitor; and glibenclamide, K+ATP channel blocker). The effect of phosphodiesterase V inhibitor (sildenafil citrate) on the reflex response and the pulmonary water content was also examined and compared with venom-induced responses. Results:, Intravenous injection of PDG (10 ,g kg,1) evoked apnoea, bradycardia and hypotension lasting >60 s. Exposure to MBT venom (100 ,g kg,1) for 30 min augmented the PDG reflex responses by two times and increased the pulmonary water content, significantly. Hoe 140 blocked the venom-induced responses (augmentation of PDG reflex and increased pulmonary water content) whereas des-Arg did not. l -NAME, methylene blue or glibenclamide also blocked the venom-induced responses. Furthermore, sildenafil citrate (that increases cGMP levels) produced augmentation of PDG reflex response and increased the pulmonary water content as seen with venom. Conclusion:, The results indicate that venom-induced responses involve B2 kinin receptors via the NO-dependent guanylate cyclase-cGMP pathway involving K+ATP channels. [source]

Chronic inhibition of standing behaviour alters baroreceptor reflex function in rats

ACTA PHYSIOLOGICA, Issue 3 2009
H. Waki
Abstract Aim:, To investigate whether daily orthostatic stress during development is an important factor affecting arterial baroreceptor reflex function, we examined the effect of chronic inhibition of upright standing behaviour on the baroreceptor reflex function in rats. Methods:, Upright standing behaviour was chronically inhibited during the developmental period between 3 and 8 weeks of age in Sprague,Dawley rats and heart rate (HR) and aortic nerve activity in response to increased and decreased mean arterial pressure (MAP) was measured after the treatment period. Results:, The baroreceptor cardiac gain in the rats grown without standing behaviour was significantly lower than the control rats grown in a normal commercial cage (1.0 ± 0.1 beats min,1 mmHg,1 vs. 1.6 ± 0.2 beatsmin,1 mmHg,1, P < 0.05). The range of HR change in the MAP,HR functional curve was also lowered by chronic inhibition of orthostatic behaviour (56.2 ± 5.9 beats min,1) compared with that of the control rats (76.8 ± 6.9 beats min,1, P < 0.05). However the aortic afferent function remained normal after the treatment period, indicating that the attenuated baroreceptor reflex function may be due to other mechanisms involving functional alterations in the cardiovascular centres, efferents and/or peripheral organs. Body weight and adrenal weight were not affected by the inhibition of orthostatic behaviour, suggesting that the animals were not exposed to specific stress by this treatment. Conclusion:, These results indicate that active haemodynamic changes induced by orthostatic behaviour are an important factor for setting the basal level of reflex function during development. Moreover, our experimental model may be useful for studying mechanisms of attenuated baroreceptor reflex observed after exposure to a chronic inactive condition. [source]

Soleus T reflex modulation in response to spinal and tendinous adaptations to unilateral lower limb suspension in humans

ACTA PHYSIOLOGICA, Issue 3 2008
O. R. Seynnes
Abstract Aim:, To investigate the influence of tendinous and synaptic changes induced by unilateral lower limb suspension (ULLS) on the tendon tap reflex. Methods:, Eight young men underwent a 23-day period of ULLS. Muscle cross-sectional area (CSA), torque and electromyographic (EMG) activity of the plantar flexor muscles (normalized to the M wave), Achilles tendon,aponeurosis mechanical properties, soleus (SOL) H and T reflexes and associated peak twitch torques were measured at baseline, after 14 and 23 days of ULLS, and 1 week after resuming ambulatory activity. Results:, Significant decreases in muscle CSA (,9%), in maximal voluntary torque (,10%) and in the associated SOL EMG activity (,16%) were found after ULLS (P < 0.05). In addition to a 36% (P < 0.01) decrease in tendon,aponeurosis stiffness, normalized H reflex increased by 35% (P < 0.05). An increase in the slope (28%, P < 0.05) and intercept (85%, P < 0.05) of the T reflex recruitment curve pointed to an increase in the gain and to a decrease in the sensitivity of this reflex, possibly resulting from the decrease in the tendon,aponeurosis stiffness at low forces. Following ULLS, changes in tendinous stiffness correlated with changes in neuromuscular efficiency (peak twitch torque to reflex ratio) at higher tendon tap forces. Conclusion:, These findings point out the dual and antagonistic influences of spinal and tendinous adaptations upon the tendon tap reflex in humans under conditions of chronic unloading. These observations have potential implications for the sensitivity of the short-latency Ia stretch response involved in rapid compensatory contractions to unexpected postural perturbations. [source]

Studies of the organization of the human nociceptive withdrawal reflex,

ACTA PHYSIOLOGICA, Issue 2007
Focus on sensory convergence, stimulation site dependency
First page of article [source]

The influence of attachment representation on parental perception and interpretation of infant emotions: A multilevel approach

DEVELOPMENTAL PSYCHOBIOLOGY, Issue 5 2010
Gottfried Spangler
Abstract The aim of the study was to investigate parental perception and interpretation of infant emotional expression depending on their attachment representation. Forty-six parents' responses to infant pictures depicting positive, neutral, and negative emotions were assessed on the level of affective judgments (valence, arousal), mimic responses (facial muscle activity), and of the eyelid reflex (using the startle paradigm). Results revealed small differences between parents of different attachment representations with respect to their subjective evaluations. However, secure parents, as compared to insecure ones, showed a positive bias in their mimic responses to infant pictures. The modulation of the startle response indicated a negative evaluation of negative infant emotion expressions in dismissing parents, while an augmentation of the startle response to negative infant emotions could not be observed in secure and preoccupied parents. The findings highlight the role of attachment experiences for emotional information processing in parents and its consequences for parental behavior. © 2010 Wiley Periodicals, Inc. Dev Psychobiol 52: 411,423, 2010. [source]

Effects of excessive glucocorticoid receptor stimulation during early gestation on psychomotor and social behavior in the rat ,

DEVELOPMENTAL PSYCHOBIOLOGY, Issue 2 2010
Karine Kleinhaus
Abstract Severe psychological stress in the first trimester of pregnancy increases the risk of schizophrenia in the offspring. To begin to investigate the role of glucocorticoid receptors in this association, we determined the effects of the glucocorticoid dexamethasone (2,mg/kg), administered to pregnant rats on gestation days 6,8, on maternal behaviors and schizophrenia-relevant behaviors in the offspring. Dams receiving dexamethasone exhibited increased milk ejection bouts during nursing. Offspring of dexamethasone-treated dams (DEX) showed decreased juvenile social play and a blunted acoustic startle reflex in adolescence and adulthood, effects that were predicted by frequency of milk ejections in the dams. DEX offspring also showed increased prepulse inhibition of startle and reduced amphetamine-induced motor activity, effects not correlated with maternal behavior. It is postulated that over-stimulation of receptors targeted by glucocorticoids in the placenta or other maternal tissues during early gestation can lead to psychomotor and social behavioral deficits in the offspring. Moreover, some of these deficits may be mediated by alterations in postnatal maternal behavior and physiology produced by early gestational exposure to excess glucocorticoids. © 2010 Wiley Periodicals, Inc. Dev Psychobiol 52:121,132, 2010 [source]

The value of the Rydel-Seiffer tuning fork as a predictor of diabetic polyneuropathy compared with a neurothesiometer

DIABETIC MEDICINE, Issue 6 2004
T. Kästenbauer
Abstract Aims The aim of the study was to investigate the predictive value of the Rydel-Seiffer tuning fork for detecting diabetic neuropathy and to compare it with an electronic neurothesiometer. Methods In 2022 consecutive diabetic subjects, peripheral polyneuropathy was diagnosed by vibration perception threshold (VPT) at the tip of both great toes using a 128-Hz tuning fork and a neurothesiometer, by simple bedside tests and by the presence of neuropathic symptoms. These evaluations were further combined to diagnose peripheral nerve dysfunction (abnormal bedside tests) and symptomatic neuropathy. VPT was also measured in 175 non-diabetic control subjects to define normal values. Results VPT was normal in 1917 subjects and abnormal in 105 (5.2%) patients when measured by the tuning fork. Patients with an abnormal vibration test were significantly (P < 0.0001) older than subjects with a normal vibration sense, while diabetes duration and HbA1c of the former were also significantly elevated. The same was true for the percentages of an abnormal 10-g monofilament test (66.7% vs. 7.2%, P < 0.0001) and a missing Achilles' tendon reflex (68.6% vs. 24.8%, P < 0.0001). Finally, the VPT measured by the neurothesiometer was 2.5 times higher in patients with an abnormal tuning fork test (32.0 ± 9.8 vs. 12.5 ± 6.4 V, P < 0.0001). The plot of the difference of both methods against their mean yielded a good agreement of the two VPT measurements, and the tuning fork had a high sensitivity and positive predictive value for the diagnosis of abnormal bedside tests and for symptomatic neuropathy. Conclusion The tuning fork reliably detected peripheral neuropathy in comparison with the neurothesiometer. A tuning fork is a useful screening test for diabetic neuropathy. [source]

Perspectives of multi-modal contribution of honeybee resources to our life

ENTOMOLOGICAL RESEARCH, Issue 2008
Hidehiro HOSHIBA
Abstract The European honeybee, Apis mellifera, has been introduced to all continents and their products like honey, propolis, royal jelly and beeswax are well known. However, its contribution is not restricted to such direct products but extends into a much wider area. For example, the economic value of seed production by pollination exceeds the above-mentioned bee products. The application of F1 hybrid is increased to as much as 70% of commercial crops and flowers in Japan and honeybees are important pollinators in the F1 seed production. Incorporation into the large-scale biodiesel fuel production system by culturing rape and sunflower seeds etc. is relied on because it is good to construct possible zero-emission systems that reduce carbon dioxide and increase the rich by-products like honey and royal jelly. Bees' higher brain function and sophisticated social system of the colony opens new perspectives as a model system. Their individual ability to recognize even abstract concepts is comparable to that of higher primates. Rats or mice have no such ability. High performance learning ability of bees associated with proboscis extension reflex can be used to detect drugs at the airport. Function of the colony, on the other hand, is an excellent model for social physiology or a self-organization system. After the whole genome of A. mellifera was read in 2006 by the world consortium, consisting of more than 90 institutions from all over the world, many molecular biologists are coming into bee world. Nobody has yet succeeded in the challenge to make transgenic honeybee, so far, because of the difficulty in controlling the reproductive system headed by the queen. However, if someone succeeded in a breakthrough we will have stingless honeybees and a disease-resistant strain in the future. [source]

Behavioral effects of ivermectin in a freshwater oligochaete, Lumbriculus variegatus

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 7 2001
Jing Ding
Abstract Ivermectin is a potent antiparasitic drug against nematode and arthropod parasites. In this study, we examined the lethal and sublethal effects of ivermectin in a freshwater oligochaete, Lumbriculus variegatus. The median lethal concentration (LC50) at 72 h after ivermectin exposure was 560 nM. Sublethal endpoints focused on several stimulus-evoked locomotor behaviors: escape reflexes controlled by giant interneuron pathways, swimming and reversal, and crawling. Swimming, reversal, and crawling are controlled by nongiant interneuron pathways. Ivermectin inhibited swimming, reversal, crawling frequency, and crawling speed in a time- and concentration-dependent manner with a mean inhibitory concentration (IC50) at 3 h of 1.1, 16, 91, and 51nM, respectively. Ivermectin at 0.3 nM also significantly decreased the frequency of helical swimming waves. Picrotoxin, a Cl, channel blocker, antagonized the ivermectin-induced decrease in swimming frequency, crawling frequency, and crawling speed. There were no adverse effects on escape reflex 3 h after exposure to 300 nM ivermectin. Electrophysiological recordings showed that ivermectin had no effects on the conduction velocity of giant fiber systems. The results indicated that locomotor behaviors controlled by nongiant locomotor pathways were more sensitive to ivermectin than pathways controlled by giant interneurons and that Cl, channels may be involved in mediating ivermectin's inhibitory effects. [source]

Ictal Pattern of EEG and Muscular Activation in Symptomatic Infantile Spasms: A Videopolygraphic and Computer Analysis

EPILEPSIA, Issue 12 2002
Francesca Bisulli
Summary: ,Purpose: To investigate ictal muscular phenomena characterizing symptomatic infantile spasms (ISs) and their relation to ictal EEG. Methods: Four children with severe encephalopathy, neurologic impairment, and refractory ISs related to different dysplastic lesions, underwent videopolygraphic recordings collecting surface electromyogram (EMG) activity from several cranial and limb muscles to evaluate the pattern of muscular recruitment, duration, and side-to-side asymmetry of ISs. Acquired data were stored for off-line analysis by a computerized polygraphic system. Results: Spasms were characterized by a complex pattern of muscular activation. A constant or rostrocaudal propagation pattern was lacking in all patients. Intervals between the onset of EMG activity in different muscles in each spasm were very long: ,100,200 ms. Two patients, with hemispheric cortical dysplasia and agenesis of the corpus callosum, had asymmetric and asynchronous spasms in which the EMG onset of the muscles contralateral to the affected hemisphere constantly anticipated that of the ipsilateral ones. Backaveraging of EEG activity disclosed a high-amplitude EEG complex on the same side as the dysplastic lesion, preceding or succeeding the contralateral muscle activity onset. In the other two patients with diffuse cortical dysplasia, no EEG transient was related to EMG activity onset. Conclusions: Despite clinical similarity between spasms in the same patient, our data demonstrate the complexity and heterogeneity of these motor phenomena. Our findings cannot be explained simply in terms of cortical or reticular generators like other motor phenomena such as cortical myoclonus or startle reflex. [source]

High prevalence of vasomotor reflex impairment in newly diagnosed leprosy patients

EUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 10 2005
X. Illarramendi
Abstract Background, Initial nerve damage in leprosy occurs in small myelinated and unmyelinated nerve fibers. Early detection of leprosy in the peripheral nervous system is challenging as extensive nerve damage may take place before clinical signs of leprosy become apparent. Patients and methods, In order to determine the prevalence of, and factors associated with, peripheral autonomic nerve dysfunction in newly diagnosed leprosy patients, 76 Brazilian patients were evaluated prior to treatment. Skin vasomotor reflex was tested by means of laser Doppler velocimetry. Blood perfusion and reflex vasoconstriction following an inspiratory gasp were registered on the second and fifth fingers. Results, Vasomotor reflex was impaired in at least one finger in 33/76 (43%) patients. The fifth fingers were more frequently impaired and suffered more frequent bilateral alterations than the second fingers. Multivariate regression analysis showed that leprosy reaction (adjusted odds ratio = 8·11, 95% confidence interval: 1·4,48·2) was associated with overall impaired vasomotor reflex (average of the four fingers). In addition, palmar erythrocyanosis and an abnormal upper limb sensory score were associated with vasomotor reflex impairment in the second fingers, whereas anti-phenolic glycolipid-I antibodies, ulnar somatic neuropathy and a low finger skin temperature were associated with impairment in the fifth fingers. Conclusions, A high prevalence of peripheral autonomic dysfunction as measured by laser Doppler velocimetry was observed in newly diagnosed leprosy patients, which is clinically evident late in the disease. Autonomic nerve lesion was more frequent than somatic lesions and was strongly related to the immune-inflammatory reaction against M. leprae. [source]

PRECLINICAL STUDY: Mice lacking Gad2 show altered behavioral effects of ethanol, flurazepam and gabaxadol

ADDICTION BIOLOGY, Issue 1 2010
Yuri A. Blednov
ABSTRACT ,-Aminobutyric acid (GABA) is synthesized in brain by two isoforms of glutamic acid decarboxylase (Gad), Gad1 and Gad2. Gad1 provides most of the GABA in brain, but Gad2 can be rapidly activated in times of high GABA demand. Mice lacking Gad2 are viable whereas deletion of Gad1 is lethal. We produced null mutant mice for Gad2 on three different genetic backgrounds: predominantly C57BL/6J and one or two generations of backcrossing to 129S1/SvimJ (129N1, 129N2). We used these mice to determine if actions of alcohol are regulated by synthesis of GABA from this isoform. We also studied behavioral responses to a benzodiazepine (flurazepam) and a GABAA receptor agonist (gabaxadol). Deletion of Gad2 increased ethanol palatability and intake and slightly reduced the severity of ethanol-induced withdrawal, but these effects depended strongly on genetic background. Mutant mice on the 129N2 background showed the above three ethanol behavioral phenotypes, but the C57BL/6J inbred background did not show any of these phenotypes. Effects on ethanol consumption also depended on the test as the mutation did not alter consumption in limited access models. Deletion of Gad2 reduced the effect of flurazepam on motor incoordination and increased the effect of extrasynaptic GABAA receptor agonist gabaxadol without changing the duration of loss of righting reflex produced by these drugs. These results are consistent with earlier proposals that deletion of Gad2 (on 129N2 background) reduces synaptic GABA but also suggest changes in extrasynaptic receptor function. [source]

PRECLINICAL STUDY: Circadian regulation of central ethanol sensitivity by the mPer2 gene

ADDICTION BIOLOGY, Issue 3 2009
Stéphanie Perreau-Lenz
ABSTRACT The effect of alcohol is known to vary with the time of the day. Although initially it was suggested that this phenomenon may be due to diurnal differences in ethanol metabolism, more recent studies were contradicting. In the present study, we therefore first set out in assessing the diurnal variations in ethanol sensitivity in mice analysing, concurrently, ethanol elimination rates. Ethanol-induced (3.5 g/kg; intraperitoneal) loss of righting reflex (LORR) duration was thus determined at several Zeitgeber time (ZT) points (ZT5, 11, 17 and 23) in C57BL/6N mice. In parallel, the corresponding ethanol elimination rates were also assessed. The results display the existence of a distinct diurnal rhythm in LORR duration peaking at ZT11, whereas no differences could be observed regarding the elimination rates of alcohol. Successively, we checked the involvement of the clock genes mPer1 and mPer2 in conveying this rhythm in sensitivity, testing LORR and hypothermia at the peak and trough previously observed (ZT5 and ZT11). Per1Brdm1 mice demonstrate a similar diurnal pattern as control mice, with enhanced LORR durations at ZT11. In contrast, Per2Brdm1 mice did not exhibit a temporal variation to the depressant effects of ethanol with respect to LORR, revealing a constant high sensitivity to ethanol. The present study reveals a central role of the mPer2 gene in inhibiting alcohol sensitivity at the beginning of the inactive phase. [source]

Intrafusal effects of botulinum toxin in post-stroke upper limb spasticity

EUROPEAN JOURNAL OF NEUROLOGY, Issue 4 2008
C. Trompetto
A previous study in subjects with focal dystonia suggested that the greater and longer-lasting effect induced by botulinum toxin type A (BoNT-A) on the tonic vibration reflex (TVR) than on the maximal M-wave (M-max) might be the physiological marker of the toxin's action at the level of intrafusal muscle fibres. With this approach, we investigated the possible effect of BoNT-A on fusimotor synapses in eight patients with post-stroke spasticity (four with no residual motor capacity before treatment and four with partially spared muscle strength and residual motor capacity). TVR and M-max were recorded from the wrist and finger flexor muscles before treatment and at 1, 4 and 7 months afterwards. The TVR reduction was greater than the M-max reduction and remained fairly constant over time only in the subjects with a residual motor capacity before the treatment. This pilot study suggests that some degree of strength and active movement is necessary for the action of BoNT-A on intrafusal fibres. [source]

Correlation of a high D-dimer level with poor outcome in traumatic intracranial hemorrhage

EUROPEAN JOURNAL OF NEUROLOGY, Issue 10 2007
J.-R. Kuo
The correlations between D-dimer and Glasgow Coma Scale (GCS), pupillary light reflex, distance of midline shift on brain computed tomography (CT), and Glasgow Outcome Score (GOS) in patients with trauma/non-trauma intracranial hemorrhage (ICH) are not consistent in studies. Ninety-eight traumatic and 59 non-traumatic ICH patients were studied. Pre-existing venous thrombosis, recent surgery, drug use (aspirin or coumadin), or malignancy, were excluded. D-dimer level was estimated within hours after acute insult, and statistical analyses were used for comparisons between groups. Traumatic ICH patients had higher D-dimer levels than controls (2984 vs. 256 ,g/l; P = 0.001). The GCS, midline shift on brain CT, pupillary reflex, and GOS at 3 months were significantly correlated with high D-dimer value in traumatic patients (individual P < 0.001), but not in the non-traumatic group. Using receiver-operating characteristic curve (ROC), the cutoff point was 1496 ,g/l, with sensitivity and specificity of 100% and 83%, respectively. D-dimer ,1496 ,g/l predicted a poor outcome [adjusted odds ratio (OR) 14.44, 95% CI 1.16,179.27; P = 0.038]. A high D-dimer level is associated with a poor outcome in patients with traumatic ICH. It can be used in addition to neurological assessment to predict the outcome. [source]