AMERICAN JOURNAL OF TRANSPLANTATION, Issue 12 2008
Z. Li
The growing development of composite tissue allografts (CTA) highlights the need for tolerance induction protocols. Herein, we developed a mouse model of heterotopic limb allograft in a stringent strain combination in which potentially tolerogenic strategies were tested taking advantage of donor stem cells in the grafted limb. BALB/c allografts were transplanted into C57BL/6 mice treated with anti-CD154 mAb, nondepleting anti-CD4 combined to either depleting or nondepleting anti-CD8 mAbs. Some groups received additional rapamycin. Both depleting and nondepleting mAb combinations without rapamycin only delayed limb allograft rejection, whereas the addition of rapamycin induced long-term allograft survival in both combinations. Nevertheless, robust donor-specific tolerance, defined by the acceptance of a fresh donor-type skin allograft and simultaneous rejection of third-party grafts, required initial CD8+ T-cell depletion. Mixed donor-recipient chimerism was observed in lymphoid organs and recipient bone marrow of tolerant but not rejecting animals. Tolerance specificity was confirmed by the inability to produce IL-2, IFN-, and TNF-, in MLC with donor antigen while significant alloreactivity persisted against third- party alloantigens. Collectively, these results show that robust CTA tolerance and mixed donor-recipient chimerism can be achieved in response to the synergizing combination of rapamycin, transient CD8+ T-cell depletion and costimulation/coreceptor blockade. [source]

NERVE STIMULATION IN THYROID SURGERY: IS IT REALLY USEFUL?

ANZ JOURNAL OF SURGERY, Issue 5 2007
Thorbjorn J Loch-Wilkinson
Background: Monitoring of the recurrent laryngeal nerve (RLN) has been claimed in some studies to reduce rates of nerve injury during thyroid surgery compared with anatomical dissection and visual identification of the RLN alone, whereas other studies have found no benefit. Continuous monitoring with endotracheal electrodes is expensive whereas discontinuous monitoring by laryngeal palpation with nerve stimulation is a simple and inexpensive technique. This study aimed to assess the value of nerve stimulation with laryngeal palpation as a means of identifying and assessing the function of the RLN and external branch of the superior laryngeal nerve (EBSLN) during thyroid surgery. Methods: This was a prospective case series comprising 50 consecutive patients undergoing total thyroidectomy providing 100 RLN and 100 EBSLN for examination. All patients underwent preoperative and postoperative vocal cord and voice assessment by an independent ear, nose and throat surgeon, laryngeal examination at extubation and all were asked to complete a postoperative dysphagia score sheet. Dysphagia scores in the study group were compared with a control group (n = 20) undergoing total thyroidectomy without nerve stimulation. Results: One hundred of 100 (100%) RLN were located without the use of the nerve stimulator. A negative twitch response occurred in seven (7%) RLN stimulated (two bilateral, three unilateral). Postoperative testing, however, only showed one true unilateral RLN palsy postoperatively (1%), which recovered in 7 weeks giving six false-positive and one true-positive results. Eighty-six of 100 (86%) EBSLN were located without the nerve stimulator. Thirteen of 100 (13%) EBSLN could not be identified and 1 of 100 (1%) was located with the use of the nerve stimulator. Fourteen per cent of EBSLN showed no cricothyroid twitch on EBSLN stimulation. Postoperative vocal function in these patients was normal. There were no instances of equipment malfunction. Dysphagia scores did not differ significantly between the study and control groups. Conclusion: Use of a nerve stimulator did not aid in anatomical dissection of the RLN and was useful in identifying only one EBSLN. Discontinuous nerve monitoring by stimulation during total thyroidectomy confers no obvious benefit for the experienced surgeon in nerve identification, functional testing or injury prevention. [source]

DOPAMINE D2 RECEPTOR STIMULATION INHIBITS ANGIOTENSIN II-INDUCED HYPERTROPHY IN CULTURED NEONATAL RAT VENTRICULAR MYOCYTES

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 3 2009
Hong Li
SUMMARY 1Myocardial hypertrophy is a common pathological change that accompanies cardiovascular disease. Dopamine D2 receptors have been demonstrated in cardiovascular tissues. However, the pathophysiological involvement of D2 receptors in myocardial hypertrophy is unclear. Therefore, the effects of the D2 receptor agonist bromocriptine and the D2 receptor antagonist haloperidol on angiotensin (Ang) II- or endothelin (ET)-1-induced hypertrophy of cultured neonatal rat ventricular myocytes were investigated in the present study. 2Protein content and protein synthesis, determined by examining [3H]-leucine uptake, were used as estimates of cardiomyocyte hypertrophy. The expression of D2 receptor protein in neonatal rat ventricular myocytes was determined using western blotting. Changes in [Ca2+]i in cardiomyocytes were observed by laser scanning confocal microscopy. 3Angiotensin II and ET-1, both at 10 nmol/L, induced myocyte hypertrophy, as demonstrated by increased protein content and synthesis, [Ca2+]i levels, protein kinase C (PKC) activity and phosphorylation of extracellular signal-regulated kinase, c-Jun N-terminal kinase and mitogen-activated protein kinase (MAPK) p38 (p38). Concomitant treatment of cells with 10 nmol/L AngII plus 10 µmol/L bromocriptine significantly inhibited cardiomyocyte hypertrophy, MAPK phosphorylation and PKC activity in the membrane, as well as [Ca2+]i signalling pathways, compared with the effects of AngII alone. In addition, 10 µmol/L bromocriptine significantly inhibited cardiomyocyte hypertrophy induced by 10 nmol/L ET-1. However, pretreatment with haloperidol (10 µmol/L) had no significant effects on cardiomyocyte hypertrophy induced by either AngII or ET-1. 4In conclusion, D2 receptor stimulation inhibits AngII-induced hypertrophy of cultured neonatal rat ventricular myocytes via inhibition of MAPK, PKC and [Ca2+]i signalling pathways. [source]

STIMULATION OF OESTROGEN RECEPTOR-EXPRESSING ENDOTHELIAL CELLS WITH OESTROGEN REDUCES PROLIFERATION OF COCULTURED VASCULAR SMOOTH MUSCLE CELLS

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 3 2008
Malin Odenlund
SUMMARY 1Oestrogen reduces vascular smooth muscle cell proliferation in mouse vascular injury models. Data on the antiproliferative effect of oestrogen in cultured vascular smooth muscle cells (VSMC) are less conclusive than those obtained in whole animal studies. 2In the present study, we investigated the hypothesis that oestrogen-induced attenuation of VSMC proliferation is facilitated by the presence of endothelial cells (EC) using a coculture system of EC and VSMC. 3Treatment with a physiological concentration of oestrogen (17,-estradiol (E2); 100 nmol/L) had no effect on fetal calf serum (FCS)-stimulated DNA synthesis in either A7r5 VSMC or bEnd.3 EC. However, stimulation of bEnd. 3 cells with E2 in a coculture system of bEnd.3 and A7r5 cells reduced FCS-induced DNA synthesis in A7r5 cells by approximately 45%. The nitric oxide synthase inhibitor NG -nitro- l- arginine methyl ester (l -NAME; 100 µmol/L) did not reverse the oestrogen-induced attenuation of DNA synthesis. The antiproliferative effect of E2 may be mediated via either oestrogen receptor (ER) ,, ER, or both because the bEnd.3 cells expressed immunoreactivity for both ER subtypes. 4These data show that ER,- and ER,-expressing endothelial cells, which are stimulated with a physiological concentration of oestrogen, release a factor(s) that arrests the proliferation of cocultured VSMC. Oestrogen-induced attenuation of vascular smooth muscle cell proliferation is not prevented by l -NAME, suggesting that a mechanism other than endothelial NO is involved. [source]

Cardio-respiratory reflexes evoked by phenylbiguanide in rats involve vagal afferents which are not sensitive to capsaicin

ACTA PHYSIOLOGICA, Issue 1 2010
A. Dutta
Abstract Aim:, Stimulation of pulmonary C fibre receptors by phenylbiguanide (PBG, 5-HT3 agonist) produces hypotension, bradycardia and tachypnoea or apnoea. However, tachypnoeic or apnoeic responses are not consistent. Therefore, this study was undertaken to delineate the actions of PBG on respiration and compared with those evoked by capsaicin (TRPV1 agonist). Methods:, Blood pressure, respiratory excursions and ECG were recorded in urethane anaesthetized adult rats. The effect of PBG or capsaicin was evaluated before and after ondansetron (5-HT3 antagonist), capsazepine (TRPV1 antagonist) or bilateral vagotomy. In addition, their effect on vagal afferent activity was also evaluated. Results:, Bolus injection of PBG produced concentration-dependent (0.1,100 ,g kg,1) hypotensive and bradycardiac responses, while there was tachypnoea at lower concentrations (0.1,3 ,g kg,1) and apnoea at higher concentrations (10,100 ,g kg,1). After vagotomy or after exposure to ondansetron both tachypnoeic and apnoeic responses were abolished along with cardiovascular responses. However, capsazepine (3 mg kg,1) did not block the PBG-induced reflex responses. Capsaicin (0.1,10 ,g kg,1), on the other hand, produced a concentration-dependent apnoea, hypotension and bradycardia but tachypnoea was not observed. Ondansetron failed to block the capsaicin-induced reflex response while bilateral vagotomy abolished bradycardiac and hypotensive responses and attenuated the apnoeic response. In another series, vagal afferent activity and cardio-respiratory changes evoked by PBG were blocked by ondansetron. However, capsaicin failed to activate the PBG-sensitive vagal afferents even though cardio-respiratory alterations were observed. Conclusions:, The present observations indicate that PBG produced tachypnoea at a lower concentration and apnoea at a higher concentration involving vagal afferents which are different from those excited by capsaicin. [source]

Regulation of early response genes in pancreatic acinar cells: external calcium and nuclear calcium signalling aspects

ACTA PHYSIOLOGICA, Issue 1 2009
N. Fedirko
Abstract Nuclear calcium signalling has been an important topic of investigation for many years and some aspects have been the subject of debate. Our data from isolated nuclei suggest that the nuclear pore complexes (NPCs) are open even after depletion of the Ca2+ store in the nuclear envelope (NE). The NE contains ryanodine receptors (RyRs) and Ins(1,4,5)P3 receptors [Ins(1,4,5)P3Rs], most likely on both sides of the NE and these can be activated separately and independently: the RyRs by either NAADP or cADPR, and the Ins(1,4,5)P3Rs by Ins(1,4,5)P3. We have also investigated the possible consequences of nuclear calcium signals: the role of Ca2+ in the regulation of immediate early genes (IEG): c-fos, c-myc and c-jun in pancreatic acinar cells. Stimulation with Ca2+ -mobilizing agonists induced significant increases in levels of expression. Cholecystokinin (CCK) (10 nm) evoked a substantial rise in the expression levels, highly dependent on external Ca2+: the IEG expression level was lowest in Ca2+ -free solution, increased at the physiological level of 1 mm [Ca2+]o and was maximal at 10 mm [Ca2+]o, i.e.: 102 ± 22% and 163 ± 15% for c-fos; c-myc ,73 ± 13% and 106 ± 24%; c-jun ,49 ± 8% and 59 ± 9% at 1 and 10 mm of extracellular Ca2+ respectively. A low CCK concentration (10 pm) induced a small increase in expression. We conclude that extracellular Ca2+ together with nuclear Ca2+ signals induced by CCK play important roles in the induction of IEG expression. [source]

Protein kinases A and C stimulate the Na+ active transport in frog skeletal muscle without an appreciable change in the number of sarcolemmal Na+ pumps

ACTA PHYSIOLOGICA, Issue 4 2005
R. A. Venosa
Abstract Aim:, The activation of both protein kinases A (PKA) and protein kinases C (PKC) in some cell types increases and in others reduces active Na+ efflux. These effects have been ascribed to either a change in the rate of ionic translocation by a fixed number of Na+ pumps or, a change in the number of plasma membrane pumps. The purpose of the present experiments was to study the effect of activating PKA and PKC on the Na+ extrusion by the Na+ pump in frog skeletal muscle. Methods:, Na+ (22Na+) fluxes and ouabain (3H-ouabain) binding were measured in frog sartorius muscles. Results:, Both activation of PKA and PKC increased the active Na+ extrusion by a factor of two; these effects were not additive. Ouabain binding experiments indicated that the pump stimulation by activation of these kinases is not associated with any significant increase in the number of plasma membrane pumps. Stimulation of the active Na+ efflux by protein kinase activation (no change in the number of sarcolemmal pumps) and by hypotonicity (increase in the number of pumps) could be elicited in the same preparation and they were additive. Conclusion:, It is concluded that in frog skeletal muscle fibres, (1) activation of both PKA and PKC stimulate the Na+ pump by increasing its rate of ionic translocation; and (2) two modes of Na+ active transport (with and without an increase in the number of pumps) are operative, and can be at work simultaneously, a phenomenon to be reckoned with. [source]

Measurement of barbed ends, actin polymerization, and motility in live carcinoma cells after growth factor stimulation,

CYTOSKELETON, Issue 4 2004
Mike Lorenz
Abstract Motility is associated with the ability to extend F-actin-rich protrusions and depends on free barbed ends as new actin polymerization sites. To understand the function and regulation of different proteins involved in the process of generating barbed ends, e.g., cofilin and Arp2/3, fixed cell approaches have been used to determine the relative barbed end concentration in cells. The major disadvantages of these approaches are permeabilization and fixation of cells. In this work, we describe a new live-cell time-lapse microscopy assay to determine the increase of barbed ends after cell stimulation that does not use permeabilization and provides a better time resolution. We established a metastatic carcinoma cell line (MTLn3) stably expressing GFP-,-actin at physiological levels. Stimulation of MTLn3 cells with epidermal growth factor (EGF) causes rapid and transient lamellipod protrusion along with an increase in actin polymerization at the leading edge, which can be followed in live cell experiments. By measuring the increase of F-actin at the leading edge vs. time, we were able to determine the relative increase of barbed ends after stimulation with a high temporal resolution. The F-actin as well as the barbed end concentration agrees well with published data for this cell line. Using this newly developed assay, a decrease in lamellipod extension and a large reduction of barbed ends was documented after microinjecting an anti-cofilin function blocking antibody. This assay has a high potential for applications where rapid changes in the dynamic filament population are to be measured. Cell Motil. Cytoskeleton 57:207,217, 2004. © 2004 Wiley-Liss, Inc. [source]

Differential Long-Term Stimulation of Type I versus Type III Collagen After Infrared Irradiation

DERMATOLOGIC SURGERY, Issue 7 2009
YOHEI TANAKA MD
BACKGROUND The dermis is composed primarily of type I (soft) and type III (rigid scar-like) collagen. Collagen degradation is considered the primary cause of skin aging. Studies have proved the efficacy of infrared irradiation on collagen stimulation but have not investigated the differential long-term effects of infrared irradiation on type I and type III collagen. OBJECTIVE To determine differential long-term stimulation of type I and type III collagen after infrared (1,100,1,800 nm) irradiation. METHODS AND MATERIALS In vivo rat tissue was irradiated using the infrared device. Histology samples were analyzed for type I and III collagen stimulation, visual changes from baseline, and treatment safety up to 90 days post-treatment. RESULTS Infrared irradiation provided long-term stimulation of type I collagen and temporary stimulation of type III collagen. Treatment also created long-term smoothing of the epidermis, with no observed complications. CONCLUSIONS Infrared irradiation provides safe, consistent, long-term stimulation of type I collagen but only short-term stimulation in the more rigid type III collagen. This is preferential for cosmetic patients looking for improvement in laxity and wrinkles while seeking smoother, more youthful skin. [source]

Increased Glycosaminoglycans Production in Sclerosing Basal Cell Carcinoma-Derived Fibroblasts and Stimulation of Normal Skin Fibroblast Glycosaminoglycans Production by a Cytokine-Derived from Sclerosing Basal Cell Carcinoma

DERMATOLOGIC SURGERY, Issue 11 2000
Ronald L. Moy MD
Sclerosing basal cell carcinoma (S-BCC) is characterized by an abundant stroma. There is evidence that some tumor cells secrete cytokines that are mitogenic for stromal fibroblasts (FBs). From this study we report increased glycosaminoglycan (GAG) production by cultures of S-BCC FBs in comparison to cultures of nodular BCC (N-BCC) FBs and normal skin FBs. GAG production was measured by cetylpyridinium chloride precipitation of incorporated [3H]-glucosamine. The sclerosing BCC FBs demonstrated a significant increase in production of GAG over control FBs (P < .001) and over N-BCC FBs (P < .001). Values reported as a mean percentage ± SEM for GAG production by S-BCC over control normal skin FBs are 359 ± 28 and over N-BCC FBs are 266 ± 27. In additional experiments, cell extract dilutions from S-BCC tumor, normal dermis, and normal epidermis were incubated with cultures of normal skin FBs. S-BCC-conditioned media was also incubated with normal FBs and GAG production was measured. For both S-BCC extracts and conditioned media, a dose response curve was established showing increased GAG production by normal FBs in relation to increasing the concentration of S-BCC extract or conditioned media. When S-BCC extract was added to normal FBs there was increased GAG production in comparison to normal FBs incubated with dermal or epidermal extracts (P < .001) for both. Two growth factors, transforming growth factor-, (TGF-,) and platelet-derived growth factor (PDGF), already known to be mitogenic for FBs, were incubated with N-BCC and normal FBs in an effort to elucidate the potential cytokine(s) released by S-BCC, causing increased GAG production by surrounding FBs. Neither of these cytokines proved to be effective in promoting a significant increase in GAG production. Our findings support the hypothesis that BCCs release factors that alter stromal FB production of GAG. [source]

Immediate effect of percutaneous intramuscular stimulation during gait in children with cerebral palsy: a feasibility study

DEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 10 2005
Margo N Orlin PT PhD PCS
The feasibility of percutaneous intramuscular functional electrical stimulation (P-FES) in children with cerebral palsy (CP) for immediate improvement of ankle kinematics during gait has not previously been reported. Eight children with CP (six with diplegia, two with hemiplegia; mean age 9 years 1 month [SD 1y 4mo; range 7y 11mo to 11y 10mo]) had percutaneous intramuscular electrodes implanted into the gastrocnemius (GA) and tibialis anterior (TA) muscles of their involved limbs. Stimulation was provided during appropriate phases of the gait cycle in three conditions (GA only, TA only, and GA/TA). Immediately after a week of practice for each stimulation condition, a gait analysis was performed with and without stimulation. A significant improvement in peak dorsiflexion in swing for the more affected extremity and dorsiflexion at initial contact for the less affected extremity were found in the GA/TA condition. Clinically meaningful trends were evident for improvements in dorsiflexion kinematics for the more and less affected extremities in the TA only and GA/TA conditions. The results suggest that P-FES might immediately improve ankle kinematics in children with CP. [source]

High-frequency stimuli preferentially release large dense-core vesicles located in the proximity of nonspecialized zones of the presynaptic membrane in sympathetic ganglia

DEVELOPMENTAL NEUROBIOLOGY, Issue 4 2008
F. Cifuentes
Abstract We characterized the effect of a brief high-frequency stimulus on the number, distribution, and optical density of large dense-core vesicles (LDCVs) in the nerve terminals of the rat superior cervical ganglia. From 4.21 ± 0.37 LDCVs/bouton detected in control nerve terminals, a stimulus of 40 Hz for 1 min released 41% of LDCVs, decreasing their number to 2.48 ± 0.14 LDCVs/bouton (p = 0.0009). In control ganglia, most dense vesicles were located close to the plasma membrane (at ,100 nm); in contrast, in stimulated ganglia they were broadly distributed with respect to the active zone. The mean distance of LDCVs to membrane and active zones was 95 ± 8 nm and 473 ± 15 nm, respectively. The analysis of the core density showed that both groups had a similar asymmetric distribution with the same average. Stimulation preferentially released those vesicles located ,100 nm from the plasma membrane that had no apparent relationship with the active zone. After the stimulus, the average distances of LDCVs to the plasma membrane and active zone did not change, suggesting that the stimulus also caused the relocation of inner LDCVs. Interestingly, optical density analysis showed that the released vesicles had low range densities, and suggested that LDCVs release their entire content. We conclude that LDCV exocytosis mainly involves those vesicles located ,100 nm from the plasma membrane and occurs in regions of synaptic boutons presumed to be nonspecialized. These results agree with the characteristics of the classical model that proposes full content release. © 2008 Wiley Periodicals, Inc. Develop Neurobiol, 2008. [source]

Critical and sensitive periods for reversing the effects of mechanosensory deprivation on behavior, nervous system, and development in Caenorhabditis elegans

DEVELOPMENTAL NEUROBIOLOGY, Issue 11 2007
Susan Rai
Abstract In these studies the nematode Caenorhabditis elegans was used as a model to investigate ways to reverse the effects of mechanosensory deprivation on behavior and development. Rose et al. (J Neurosci 2005; 25:7159,7168) showed that worms reared in isolation responded significantly less to a mechanical tap stimulus, were significantly smaller, and expressed significantly lower levels of a postsynaptic glutamate receptor subunit on the command interneurons of the tap response circuit and a presynaptic vesicle marker in the tap sensory neurons compared with worms raised in groups. Here, brief mechanical stimulation at any time throughout development reversed the effects of isolation on the response to tap and on postsynaptic glutamate receptor expression on the command interneurons, suggesting there is no critical period for these measures. In contrast to the high level of plasticity in glutamate receptor subunit expression on the interneurons, low levels of stimulation only rescued vesicle expression in the tap sensory neurons early in development and progressively higher levels of stimulation were required as the worm developed, suggesting a sensitive period immediately after hatching, followed by a period of decreasing plasticity. Stimulation during the first three stages of larval development, but not later, rescued the effects of isolation on worm length, suggesting there is a critical period for this measure that ends in the third larval stage. These results indicate that different effects of early isolation required different amounts and/or timing of stimulation to be reversed. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2007. [source]

Activity alters muscle reinnervation and terminal sprouting by reducing the number of schwann cell pathways that grow to link synaptic sites

DEVELOPMENTAL NEUROBIOLOGY, Issue 4 2003
Flora M. Love
Abstract In partially denervated rodent muscle, terminal Schwann cells (TSCs) located at denervated end plates grow processes, some of which contact neighboring innervated end plates. Those processes that contact neighboring synapses (termed "bridges") appear to initiate nerve terminal sprouting and to guide the growth of the sprouts so that they reach and reinnervate denervated end plates. Studies conducted prior to knowledge of this potential involvement of Schwann cells showed that direct muscle stimulation inhibits terminal sprouting following partial denervation (Brown and Holland, 1979). We have investigated the possibility this inhibition results from an alteration in the growth of TSC processes. We find that stimulation of partially denervated rat soleus muscle does not alter the length or number of TSC processes but does reduce the number of TSC bridges. Stimulation also reduces the number of TSC bridges that form between end plates during reinnervation of a completely denervated muscle. The nerve processes ("escaped fibers") that normally grow onto TSC processes during reinnervation are also reduced in length. Therefore, stimulation alters at least two responses to denervation in muscles: (1) the ability of TSC processes to form or maintain bridges with innervated synaptic sites, and (2) the growth of axons along processes extended by TSCs. © 2003 Wiley Periodicals, Inc. J Neurobiol 54: 566,576, 2003 [source]

Effect of Inotropic Stimulation on Left Atrial Appendage Function in Atrial Myopathy of Chronic Atrial Fibrillation

ECHOCARDIOGRAPHY, Issue 4 2000
MASOOR KAMALESH M.D.
Atrial fibrillation (AF) leads to remodeling of the left atrium (LA) and left atrial appendage (LAA), resulting in atrial myopathy. Reduced LA and LAA function in chronic AF leads to thrombus formation and spontaneous echo contrast (SEC). The effect of inotropic stimulation on LAA function in patients with chronic AF is unknown. LAA emptying velocity (LAAEV) and maximal LAA area at baseline and after dobutamine were measured by transesophageal echocardiography in 14 subjects in normal sinus rhythm (NSR) and 6 subjects in AF. SEC in the LA was assessed before and after dobutamine. LAAEV increased significantly in both groups. However, the LAAEV at peak dobutamine in patients with AF remained significantly lower than the baseline LAAEV in patients who were in NSR (P= 0.009). Maximal LAA area decreased significantly with dobutamine in both groups, but LAA area at peak dose of dobutamine inpatients with AF remained greater than baseline area in those in NSR (P= 0.01). Despite the increase in LAAEV, SEC improved in only two of five patients. We conclude that during AF, the LAA responds to inotropic stimulation with only a modest improvement in function. [source]

Repeated high-frequency transcranial magnetic stimulation over the dorsolateral prefrontal cortex reduces cigarette craving and consumption

ADDICTION, Issue 4 2009
Revital Amiaz
ABSTRACT Aims To evaluate the effect of repeated high-frequency transcranial magnetic stimulation (rTMS) of the left dorsolateral prefrontal cortex (DLPFC), combined with either smoking or neutral cues, on cigarette consumption, dependence and craving. Design Participants were divided randomly to real and sham stimulation groups. Each group was subdivided randomly into two subgroups presented with either smoking-related or neutral pictures just before the daily TMS intervention. Ten daily rTMS sessions were applied every week-day and then a maintenance phase was conducted in which rTMS sessions were less frequent. Setting Single-site, out-patient, randomized, double-blind, sham-controlled. Participants Forty-eight chronic smokers who smoked at least 20 cigarettes per day and were motivated to quit smoking. Healthy males and females were recruited from the general population using advertisements in newspapers and on internet websites. Intervention Ten daily rTMS sessions were administered using a standard figure-8 coil over the DLPFC. Stimulation included 20 trains/day at 100% of motor threshold. Each train consisted of 50 pulses at 10 Hz with an inter-train interval of 15 seconds. Measurements Cigarette consumption was evaluated objectively by measuring cotinine levels in urine samples and subjectively by participants' self-reports. Dependence and craving were evaluated by standard questionnaires. Findings Ten daily rTMS sessions over the DLPFC reduced cigarette consumption and nicotine dependence. Furthermore, treatment blocked the craving induced by daily presentation of smoking-related pictures. However, these effects tended to dissipate over time. Conclusions Multiple high-frequency rTMS of the DLPFC can attenuate nicotine craving. [source]

Stimulation of reproductive growth in rainbow trout (Oncorhynchus mykiss) following exposure to treated sewage effluent

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 10 2006
Birgit Hoger
Abstract Rainbow trout (Oncorhynchus mykiss) were exposed to 1.5 and 15% v/v secondary treated sewage effluent for 32 weeks in flow-through mesocosms. The exposure encompassed the full period of reproductive development for rainbow trout. Trout did not show any evidence of a dose-dependent change in growth. Fish exposed to 15% effluent were the only group to show mortality (5%) over the duration of the experiment. Trout at the highest effluent concentration had significantly higher liver size than reference water fish. Both male and female trout in the 15% exposure group also exhibited significantly higher gonad weight than the reference group. In female trout, this gonad size increase could be explained by higher egg numbers. Female and male trout both displayed a significant increase in plasma 17,-estradiol levels after exposure to 15% effluent, while neither sex had dose-dependent differences in plasma testosterone. Male trout displayed elevated vitellogenin levels and reduced plasma 11-ketotestosterone concentration after exposure to 15% effluent. Chemical examination of steroidal compounds, including both estrogens and androgens, in the wastewater revealed that only estrone was detectable at a mean concentration of 4.5 ng/L. It is assumed that the effects observed in trout exposed to 15% effluent were consistent with stimulation of reproductive development due to very low levels of estrogens. Overall, long-term exposure to treated sewage effluent containing low levels of estrogen did not have significant negative implications for reproductive development in rainbow trout. [source]

Electrical Stimulation of the Hippocampal Epileptic Foci for Seizure Control: A Double-Blind, Long-Term Follow-Up Study

EPILEPSIA, Issue 10 2007
Ana Luisa Velasco
Summary:,Purpose: Our aim was to evaluate the safety and efficacy of electrical stimulation of the hippocampus in a long-term follow-up study, as well as its impact on memory performance in the treatment of patients with refractory mesial temporal lobe epilepsy. Methods: Nine patients were included. All had refractory partial complex seizures, some with secondary generalizations. All patients had a 3-month-baseline-seizure count, after which they underwent bilateral hippocampal diagnostic electrode implantation to establish focus laterality and location. Three patients had bilateral, and six, unilateral foci. Diagnostic electrodes were explanted and definitive Medtronic electrodes were implanted directed into the hippocampal foci. Position was confirmed with MRI and afterwards, the deep brain stimulation system internalized. Patients signed the informed consent approved by the Hospital's Ethics Committee and began a double-blind stimulation protocol. Patients attended a medical appointment every 3 months for seizure diary collection, deep brain stimulation system checkup, and neuropsychological testing. Results: Follow-up ranged from 18 months to 7 years. Patients were divided in two groups: five had normal MRIs and seizure reduction of >95%, while four had hippocampal sclerosis and seizure reduction of 50,70%. No patient had neuropsychological deterioration, nor did any patient show side effects. Three patients were explanted after 2 years due to skin erosion in the trajectory of the system. Conclusions: Electrical stimulation of the hippocampus provides a nonlesional method that improves seizure outcome without memory deterioration in patients with hippocampal epileptic foci. [source]

rTMS Reveals Premotor Cortex Dysfunction in Frontal Lobe Epilepsy

EPILEPSIA, Issue 2 2007
Wolfgang N. Löscher
Summary:,Purpose: Studies of motor cortex excitability provided evidence that focal epilepsies may alter the excitability of cortical areas distant from the epileptogenic zone. In order to explore this hypothesis we studied the functional connectivity between premotor and motor cortex in seven patients with frontal lobe epilepsy and seizure onset zone outside the premotor or motor cortex. Methods: Low-frequency subthreshold repetitive transcranial magnetic stimulation was applied to the premotor cortex and its impact on motor cortex excitability was measured by the amplitude of motor-evoked potentials in response to direct suprathreshold stimulation of the motor cortex. Results: Stimulation of the premotor cortex of the non-epileptogenic hemisphere resulted in a progressive and significant inhibition of the motor cortex as evidenced by a reduction of motor evoked potential amplitude. On the other hand, stimulation of the premotor cortex of the epileptogenic hemisphere failed to inhibit the motor cortex. The reduced inhibition of the motor cortex by remote areas was additionally supported by the significantly shorter cortical silent periods obtained after stimulation of the motor cortex of the epileptogenic hemisphere. Conclusion: These results show that the functional connectivity between premotor and motor cortex or motor cortex interneuronal excitability is impaired in the epileptogenic hemisphere in frontal lobe epilepsy while it is normal in the nonepileptogenic hemisphere. [source]

Combined Ketogenic Diet and Vagus Nerve Stimulation: Rational Polytherapy?

EPILEPSIA, Issue 1 2007
Eric H. Kossoff
Summary:,Objective: The concept of "rational polypharmacy" has been associated with anticonvulsant management for decades, but the term has not been applied to nonpharmacologic therapies. Methods: We conducted a multicenter, retrospective study of children who received concurrent diet (ketogenic or modified Atkins) and vagus nerve stimulation (VNS) treatment for medically intractable epilepsy. Results: Thirty children in total from six epilepsy centers were treated over a 6-yr period. The median age at the initiation of combination therapy was 10 yr (range, 4,24 yr). Sixteen (53%) received dietary therapy followed by VNS; no differences were noted between centers. After 3 months, 21 (70%) had seizure reduced by >50% over the previous single nonpharmacologic treatment, of whom 13 (62%) had improvement within the first month. A 5-min VNS off-time correlated with >90% seizure reduction (p = 0.02). The median duration of nonpharmacologic polytherapy was 12 months (range, 0.5,96 months); 17 (57%) remain on dual therapy at this time. No side effects were noted. Most patients who discontinued combination therapy did so because of a lack of efficacy rather than restrictiveness. Conclusions: In this small group, the combined use of diet and VNS appeared synergistic and yielded rapid benefits. It may be more effective with longer VNS off-times. Further prospective studies of this combination in refractory pediatric epilepsy are needed to help guide optimal use. [source]

Refractory Generalized Seizures: Response to Corpus Callosotomy and Vagal Nerve Stimulation

EPILEPSIA, Issue 1 2006
Maromi Nei
Summary:,Purpose: The vagal nerve stimulator (VNS) and corpus callosotomy can reduce seizure frequency when seizures are refractory to medications. However, the efficacy and safety of these two procedures have not been compared. This study evaluates the two procedures for generalized seizures. Methods: All patients with refractory generalized seizures (generalized tonic,clonic, tonic, or atonic) who underwent a corpus callosotomy (anterior or complete) (n = 53) without other forms of epilepsy surgery and those who underwent VNS placement (n = 25) were evaluated for this study. Seizure response and procedure complications were evaluated. Results: For those with a corpus callosotomy and generalized tonic,clonic seizures (n = 50), 79.5% had ,50% decrease in the frequency of generalized tonic,clonic seizures, and 60% had ,80% seizure reduction. For those with a VNS and generalized tonic,clonic seizures (n = 21), 50% had ,50% seizure reduction, and 33% had ,80% seizure reduction. Tonic and atonic seizures decreased after either VNS or a corpus callosotomy. The complication rate for corpus callosotomy was higher (21% all complications, 3.8% permanent) than that for VNS (8%; none permanent), but complications for both corpus callosotomy and VNS were rarely permanent. Conclusions: Both corpus callosotomy and VNS are effective in reducing generalized seizures. Corpus callosotomy is associated with greater efficacy but higher risk for complications, although these were generally transient. [source]

Preemptive Low-frequency Stimulation Decreases the Incidence of Amygdala-kindled Seizures

EPILEPSIA, Issue 1 2005
Jeffrey H. Goodman
Summary:,Purpose: The use of electrical stimulation as a therapy for epilepsy is currently being studied in experimental animals and in patients with epilepsy. This study examined the effect of preemptive, low-frequency, 1-Hz sine wave stimulation (LFS) on the incidence of amygdala-kindled seizures in the rat. Methods: Electrodes were implanted into the basolateral amygdalae of adult male rats. All animals received a kindling stimulus of 60-Hz, 400-,A, sine wave for 1 s twice a day. Experimental animals received an additional LFS consisting of 1 Hz, 50 ,A for 30 s immediately before the kindling stimulus. Afterdischarge (AD) duration, behavioral seizure score, the number of stimulations required to elicit the first stage five seizure and to become fully kindled were measured. After 20 stimulations, a crossover procedure was performed. Fully kindled rats from each group were switched, so that the original controls received LFS plus the kindling stimulus, and the original experimental rats received only the kindling stimulus. Results: During kindling acquisition, LFS induced a significant decrease in AD duration. A significant increase in the number of times the kindling stimulus failed to elicit an AD was noted. Control rats exhibited an AD 99% of the time compared with 70% in experimental rats (p < 0.0001; Fisher's Exact test). In fully kindled animals, the incidence of stage five seizures in the original controls significantly decreased from 98% to 42% (p < 0.0001) when the LFS was added to the kindling paradigm. Conclusions: The dramatic decrease in the incidence of stage 5 seizures in fully kindled animals after preemptive LFS strongly suggests that LFS may be an effective therapy for the prevention of seizures in patients with epilepsy. [source]

Brain Blood-flow Alterations Induced by Therapeutic Vagus Nerve Stimulation in Partial Epilepsy: II.

EPILEPSIA, Issue 9 2004
Low Levels of Stimulation, Prolonged Effects at High
Summary:,Purpose: To measure vagus nerve stimulation (VNS)-induced cerebral blood flow (CBF) effects after prolonged VNS and to compare these effects with immediate VNS effects on CBF. Methods: Ten consenting partial epilepsy patients had positron emission tomography (PET) with intravenous [15O]H2O. Each had three control scans without VNS and three scans during 30 s of VNS, within 20 h after VNS began (immediate-effect study), and repeated after 3 months of VNS (prolonged study). After intrasubject subtraction of control from stimulation scans, images were anatomically transformed for intersubject averaging and superimposed on magnetic resonance imaging (MRI) for anatomic localization. Changes on t-statistical maps were considered significant at p < 0.05 (corrected for multiple comparisons). Results: During prolonged studies, CBF changes were not observed in any regions that did not have CBF changes during immediate-effect studies. During both types of studies, VNS-induced CBF increases were similarly located in the bilateral thalami, hypothalami, inferior cerebellar hemispheres, and right postcentral gyrus. During immediate-effect studies, VNS decreased bilateral hippocampal, amygdalar, and cingulate CBF and increased bilateral insular CBF; no significant CBF changes were observed in these regions during prolonged studies. Mean seizure frequency decreased by 25% over a 3-month period between immediate and prolonged PET studies, compared with 3 months before VNS began. Conclusions: Seizure control improved during a period over which some immediate VNS-induced CBF changes declined (mainly over cortical regions), whereas other VNS-induced CBF changes persisted (mainly over subcortical regions). Altered synaptic activities at sites of persisting VNS-induced CBF changes may reflect antiseizure actions. [source]

Dipole Tracing Examination for the Electric Source of Photoparoxysmal Response Provoked by Half-Field Stimulation

EPILEPSIA, Issue 2000
Kazuhiko Kobayashi
Purpose: Dipole tracing (DT) is a computer-aidcd noninvasive method used to estimate the location of epileptic discharges from the scalp EEG. In DT equivalent current dipoles (ECDs), which rcflcct the electric source in the brain, are rcsponsible for the potential distribution on the scalp EEC. Thercfore, the DT method is useful to estimatc the focal paroxysmal discharges. In this study we examined the location of the clectric source of photoparoxysmal response (PPR) using scalpskull-brain dipolc tracing (SSB-DT) after hal[-field stimulation, which produced focal PPR on the scalp EEG. Methods: We studied 4 cases of photoscnsitive epilepsy. Wc performed 20 Hz red flicker and flickcring dot pattern half-ficld stimulation to provoke PPR. In this method, the loci of gcnerators corresponding to the paroxysmal discharges were estimated as ECDs by I - and 2-dipole analyses. Each location of the ECDs was estimated by iterative calculation. Algorithms minimizing the squarcd difference betwccn the electrical potentials recorded from the scalp EEG and those calculated theoretically from the voluntary dipoles were uscd. In the SSB model, the scalp shell was reconstructed from the helmet mcasurements, and the shapc of the skull and brain was 3-dimcnsionally reconstructed from CT images. A dipolarity larger than 98% w the accuracy of the estimation. We recorded thcir 2 I channel monopolar scalp EEG. Each spike was sampled analyzed at 10 points around the peaks of at least 10 spikes in each patient using the SSB-DT method. The ECDs were then supcrimposed on thc MRI of each palient to idcntify the more cxact anatomical region. Results: This study showed the location of cach focus and a dipolarity of greater than 98% in all cases, although the results from the 2-dipole method showed scattered location. We considered that the analyzed signals were generated from single source. PPR was elicitcd cross-lateral to the field stimulated. By red flicker half-field stimulation, EEG revealed eithcr focal spikes and waves in the contralatcral occipital, temporo-occipitel region, or diffuse spikes and wave complex bursts, sccn dominantly at the contralateral hcmisphere. The supcrimposed ESDs on MRI were located at the occipital or inferior temporal lobe. PPR, provoked by flickering dot pattern half-field stimulation, werc focal spikes and waves, mainly in the occipital, parieto-occipital region, or diffuse spikes and wave complcx bursts, seen dominantly at thc contralateral hcmiaphere. The ECDs of their PPRs were located in the occipital, inferior temporal, or inferior pirietal lobules on MRI. Conclusion: Our findings suggest that the inferior temporal and inferior parictal lobules which are important for the processing sequence of the visual system in addition to the occipital lobc, might he responsible for thc mechanism of PPR by half-ficld stimulation, espccially for electric source expansion. [source]

Effects of Vagus Nerve Stimulation on Progressive Myoclonus Epilepsy of Unverricht-Lundborg Type

EPILEPSIA, Issue 8 2000
Brien Smith
Summary: Purpose: A 34-year-old woman with progressive myoclonus epilepsy of Unverricht-Lundborg type was considered for vagus nerve stimulation (VNS) therapy. Methods: After demonstration of intractability to multiple antiepileptic regimens and progressive deterioration in cerebellar function, the patient was implanted with a vagus nerve stimulator and followed for 1 year. Neurological status, seizure frequency, and parameter changes were analyzed. Results: VNS therapy resulted in reduction of seizures (more than 90%) and a significant improvement in cerebellar function demonstrated on neurological examination. The patient reported improved quality of life based in part on her ability to perform activities of daily living. Conclusions: VNS therapy may be considered a treatment option for progressive myoclonus epilepsy. The effects of VNS on seizure control and cerebellar dysfunction may provide clues to the underlying mechanism(s) of action. [source]

Central Nystagmus Induced by Deep-Brain Stimulation for Epilepsy

EPILEPSIA, Issue 1 2000
Article first published online: 19 SEP 200
First page of article [source]

Considerations for pacing of the cricoarytenoid dorsalis muscle by neuroprosthesis in horses

EQUINE VETERINARY JOURNAL, Issue 6 2010
N. G. DUCHARME
Summary Reasons for performing study: The success rate of prosthetic laryngoplasty is limited and may be associated with significant sequelae. Nerve muscle pedicle transplantation has been attempted but requires a year before function is restored. Objective: To determine the optimal parameters for functional electrical stimulation of the recurrent laryngeal nerve in horses. Methods: An experimental in vivo study was performed on 7 mature horses (2,21 years). A nerve cuff was placed on the distal end of the common trunk of the recurrent laryngeal nerve (RLN). In 6 horses the ipsilateral adductor branch of RLN was also transected. The electrodes were connected to programmable internal stimulator. Stimulation was performed using cathodic phase and then biphasic pulses at 24 Hz with a 0.427 ms pulse duration. Stimulation-response experiments were performed at monthly intervals, from one week following implantation. The study continued until unit failure or the end of project (12 months). Two of the horses were stimulated continuously for 60 min to assess onset of fatigue. Results: Excellent arytenoid cartilage abduction (mean arytenoid angle of 52.7°, range 48.5,56.2°) was obtained in 6 horses (laryngeal grades I or II (n = 3) and III (n = 2). Poor abduction was obtained in grade IV horses (n = 2). Arytenoid abduction was maintained for up to a year in one horse. Technical implant failure resulted in loss of abduction in 6 horses at one week to 11 months post operatively. Mean tissue impedance was 1.06 kOhm (range 0.64,1.67 kOhm) at one week, twice this value at 2 months (mean 2.32, range 1.11,3.75 kOhm) and was stable thereafter. Maximal abduction was achieved at a stimulation range of 0.65,7.2 mA. No electrical leakage was observed. Constant stimulation of the recurrent laryngeal nerve for 60 min led to full abduction without evidence of muscle fatigue. Conclusions: Functional electrical stimulation of the recurrent laryngeal nerve leading to full arytenoid abduction can be achieved. The minimal stimulation amplitude for maximal abduction angle is slightly higher than those for man and dogs. Clinical relevance: This treatment modality could eventually be applicable to horses with recurrent laryngeal neuropathy. [source]

Role for cAMP-protein kinase A signalling in augmented neutrophil adhesion and chemotaxis in sickle cell disease

EUROPEAN JOURNAL OF HAEMATOLOGY, Issue 4 2007
Andreia A. Canalli
Abstract The significance of the leukocyte in sickle cell disease (SCD) pathophysiology is becoming increasingly recognised; we sought to examine whether the chemotactic properties of neutrophils of SCD individuals may be altered and, further, to better understand the signalling events that mediate altered SCD neutrophil function. Adhesion to immobilised fibronectin (FN) and chemotaxis of control and SCD neutrophils were assessed using in vitro static adhesion assays and 96-well chemotaxis chamber assays. Adhesion assays confirmed a significantly higher basal adhesion of SCD neutrophils to FN, compared with control neutrophils. Chemotaxis assays established, for the first time, that SCD neutrophils demonstrate greater spontaneous migration and, also, augmented migration in response to IL-8, when compared with control neutrophils. Co-incubation of SCD neutrophils with KT5720 (an inhibitor of PKA) abrogated increased basal SCD neutrophil adhesion, spontaneous chemotaxis and IL-8-stimulated chemotaxis. Stimulation of SCD neutrophils with IL-8 also significantly augmented SCD neutrophil adhesion to FN with a concomitant increase in cAMP levels and this increase in adhesion was abolished by KT5720. Interestingly, the adhesive properties of neutrophils from SCD individuals on hydroxyurea therapy were not significantly altered and results indicate that a reduction in intracellular cAMP may contribute to lower the adhesive properties of these cells. Data indicate that up-regulated cAMP signalling plays a significant role in the altered adhesive and migratory properties in SCD neutrophils. Such alterations may have important implications for the pathophysiology of the disease and the cAMP-PKA pathway may represent a therapeutic target for the abrogation of altered leukocyte function. [source]

Functional role of human NK cell receptor 2B4 (CD244) isoforms

EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 6 2009
Stephen O. Mathew
Abstract 2B4 (CD244), a member of the signaling lymphocyte-activation molecule (SLAM/CD150), is expressed on all NK cells, a subpopulation of T cells, monocytes and basophils. Human NK cells express two isoforms of 2B4, h2B4-A and h2B4-B that differ in a small portion of the extracellular domain. In the present investigation, we have studied the functions of h2B4-A and h2B4-B. Our study demonstrated that these two isoforms differ in their binding affinity for CD48, which results in differential cytotoxic activity as well as intracellular calcium release by NK cells upon target cell recognition. Analysis of the predicted 3-D structure of the two isoforms showed conformational differences that could account for their differences in binding affinity to CD48. h2B4-A was able to mediate natural cytotoxicity against CD48-expressing K562 target cells and induce intracellular calcium release, whereas h2B4-B showed no effects. NK-92MI, U937, THP-1, KU812, primary monocytes, basophils and NK cells showed expression of both h2B4-A and h2B4-B whereas YT and IL-2-activated NK cells did not show any h2B4-B expression. Stimulation of NK cells through 2B4 resulted in decreased mRNA levels of both h2B4-A and h2B4-B indicating that down-regulation of 2B4 isoforms may be an important factor in controlling NK cell activation during immune responses. [source]

The role of MAPK in governing lymphocyte adhesion to and migration across the microvasculature in inflammatory bowel disease

EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 1 2009
Franco Scaldaferri
Abstract Lymphocyte recruitment is a key pathogenic event in inflammatory bowel disease (IBD). Adhesion of T cells to human intestinal microvascular endothelial cells (HIMEC) is mediated by ICAM-1, VCAM-1 and fractalkine (FKN), but the signaling molecules that orchestrate this process have yet to be identified. Because MAPK play an important role in the response of many cell types to pro-inflammatory stimuli, we assessed the functional role of p38 MAPK, p42/44 MAPK and JNK in the regulation of lymphocyte adhesion to and chemotaxis across the microvasculature in IBD. We found that the MAPK were phosphorylated in the bowel microvasculature and human intestinal fibroblasts of patients with IBD but not of healthy individuals. Stimulation of HIMEC with TNF- , triggered phosphorylation of the MAPK, and up-regulation of VCAM-1, FKN and ICAM-1. Blockade of p38 decreased the expression of all MAPK by 50% (p<0.01), whereas inhibition of p42/44 decreased the expression of ICAM-1 and FKN by 50% (p<0.01). Treatment of human intestinal fibroblasts with TNF- , elicited production of IL-8 and MCP-1, which was reduced (p<0.05) by blockade of p38 and p42/44. Finally, blockade of p38 and p42/44 reduced lymphocyte adhesion to (p<0.05) and transmigration across (p<0.05) HIMEC monolayers. These findings suggest a critical role for MAPK in governing lymphocyte influx into the gut in IBD patients, and their blockade may offer a molecular target for blockade of leukocyte recruitment to the intestine. [source]