Utility of additional abdominopelvic CT in detecting occult cancer in patients with unprovoked venous thromboembolism.

AIM: To analyse the positive rate for cancer on additional abdominopelvic computed tomography (CT) in patients with unprovoked venous thromboembolism (VTE), evaluate the subsequent emergence of a cancer diagnosis in the clinical follow-up period, and identify any possible predictive factors of cancer in this cohort, which may allow better selection of patients for additional imaging. MATERIALS AND METHODS: Consecutive adult patients with VTE were retrospectively identified in two large teaching hospitals between January 2013 and June 2014, including a subset of those with unprovoked VTE. Relevant demographic data were extracted and analysed. All patients had a minimum of 12 months clinicoradiological follow-up. RESULTS: One thousand four hundred and forty-six patients with VTE were deemed eligible, of which 699 (48%) were male; the median age (range) was 66 (16-102) years. The prevalence of pre-existing cancer in these patients was 343/1446 (24%), and 388/1446 (27%) were classified as unprovoked VTE. In 12/1446 (0.8%), cancer was diagnosed synchronously with VTE on the initial imaging investigation. Additional screening imaging was performed in 232/388 (60%) including abdominopelvic CT in 205 (53%) patients with unprovoked VTE. Only five additional cancers were identified, all of these occurring in patients with clinical symptoms suspicious for cancer. None of the additional CT examinations identified any clinically occult cancer in asymptomatic patients, and subsequent mean follow-up of 22 (SD=6) months also failed to reveal any further cancer diagnosis. CONCLUSION: Contrary to the National Institute of Health and Care Excellence (NICE) guidance, the yield of performing additional abdominopelvic CT as a screening tool for occult cancer in asymptomatic patients with unprovoked VTE is negligible. A more selective and clinically-driven assessment of these patients is recommended.

Multicentre survey of radiologically inserted gastrostomy feeding tube (RIG) in the UK.

AIMS: To evaluate the variance in current UK clinical practice and clinical outcomes for direct percutaneous radiologically inserted gastrostomy (RIG). MATERIALS AND METHODS: A prospective UK multicentre survey of RIG performed between October 2008 and August 2010 was performed through the British Society of Gastrointestinal and Abdominal Radiology (BSGAR). RESULTS: Data from 684 patients were provided by 45 radiologists working at 17 UK centres. Two hundred and sixty-three cases (40%) were performed with loop-retained catheters, and 346 (53%) with balloon-retained devices. Sixty percent of all patients experienced pain in the first 24 h, but settled in the majority thereafter. Early complications, defined as occurring in the first 24 h, included minor bleeding (1%), wound infection (3%), peritonism (2%), and tube misplacement (1%). Late complications, defined as occurring between day 2 and day 30 post-procedure, included mild pain (30%), persisting peritonism (2%), and 30 day mortality of 1% (5/665). Pre-procedural antibiotics or anti-methicillin-resistant Staphylococcus aureus (MRSA) prophylaxis did not affect the rate of wound infection, peritonitis, post-procedural pain, or mortality. Ninety-three percent of cases were performed using gastropexy. Gastropexy decreased post-procedural pain (p < 0.001), but gastropexy-related complications occurred in 5% of patients. However, post-procedure pain increased with the number of gastropexy sutures used (p < 0.001). The use of gastropexy did not affect the overall complication rate or mortality. Post-procedure pain increased significantly as tube size increased (p < 0.001). The use of balloon-retention feeding tubes was associated with more pain than the deployment of loop-retention devices (p < 0.001). CONCLUSION: RIG is a relatively safe procedure with a mortality of 1%, with or without gastropexy. Pain is the commonest complication. The use of gastropexy, fixation dressing or skin sutures, smaller tube sizes, and loop-retention catheters significantly reduced the incidence of pain. There was a gastropexy-related complication rate in 5% of patients. Neither pre-procedural antibiotics nor anti-MRSA prophylaxis affected the rate of wound infection.

Imaging manifestations in Proteus syndrome: an unusual multisystem developmental disorder.

In this review we use images from an 11-year-old male to describe Proteus syndrome, a complex disorder with multisystem involvement and great clinical variability. Our aim is to enhance recognition of the typical imaging findings, which can aid diagnosis of this rare condition.

Neuroanatomical targets of reboxetine and bupropion as revealed by pharmacological magnetic resonance imaging.

RATIONALE: One of the key targets of psychopharmacology research is to determine the potential sites of action of antidepressants in order to characterise their underlying mechanism of action. OBJECTIVE: Using blood oxygenation level-dependent (BOLD) pharmacological magnetic resonance imaging (phMRI), the neuroanatomical target-sites of reboxetine (a selective noradrenaline reuptake inhibitor) and bupropion (an antidepressant with stimulatory effects on dopamine and potentially on noradrenaline) were mapped. METHODS: Separate groups of rats were challenged acutely or chronically (daily injections for 14 days) with saline or psychoactive compounds and scanned. Subsequent statistical parametric mapping of the main effects of the drug was performed by identifying changes in the BOLD signal. RESULTS: Acute reboxetine challenge at a low dose (10 mg/kg i.p.) produced positive BOLD responses specifically in the hypothalamus, whereas a larger dose (30 mg/kg i.p.) produced activations in the hypothalamus, anterior hippocampus and prefrontal cortex. Chronic reboxetine (30 mg/kg i.p.) treatment induced increased BOLD responses in the posterior hippocampus and prefrontal cortex, while no significant contrast changes were observed in the hypothalamus and a significant decrease was apparent in the amygdala. In contrast, acute bupropion (15 and 30 mg/kg i.p.) challenge in both doses produced no significant contrast changes in the regions of interest. However, chronic bupropion treatment (30 mg/kg i.p.) produced robust increases in BOLD responses in the hippocampus, amygdala and prefrontal cortex. CONCLUSION: In summary, this study demonstrates that reboxetine and bupropion evoke a significant increase in BOLD functional activity in specific regions of the brain, including the hypothalamus, hippocampus, prefrontal cortex and amygdala. Furthermore, the study illustrates the potential value of pharmacological MRI in rodents to delineate pharmacologically induced changes in regional brain function.

Regional differences in neurovascular coupling in rat brain as determined by fMRI and electrophysiology.

Increases in neuronal activity induce local increases in cerebral perfusion. However, our understanding of the processes underlying this neurovascular coupling remains incomplete and, particularly, how these vary across the brain. Recent work supports an important role for astrocytes in neurovascular coupling, in large part via activation of their metabotropic glutamate receptors (mGluR). Here, using a combination of functional magnetic resonance imaging (fMRI) and electrophysiology we demonstrate regional heterogeneity in the mechanisms underlying neurovascular coupling. Direct electrical stimulation of the rat hindpaw sensorimotor cortex induces blood oxygenation level dependent (BOLD) and cerebral blood volume (CBV) fMRI responses in several anatomically distinct cortical and subcortical structures. Following intraperitoneal administration of the type 5 mGluR antagonist, MPEP, both BOLD and CBV responses to cortical stimulation were significantly reduced, whilst the local field potential (LFP) responses remained largely constant. Spatially, the degree of reduction in fMRI responses varied between cortical and subcortical regions (primary cortex approximately 18% vs. striatum approximately 66%), and also between primary and secondary cortical areas ( approximately 18% vs. approximately 55%). Similarly, greater decreases in response amplitude were seen in the contralateral secondary cortex ( approximately 91%) and ipsilateral striatum (approximately 70%), compared to the primary cortex (approximately 44%). Following MPEP, a negative component of the BOLD and CBV responses became more apparent, suggesting that different mechanisms mediate vasodilatory and vasoconstrictory responses. Interestingly, under baseline conditions the quantitative relationship between fMRI and LFP responses in cortical and subcortical regions was markedly different. Our data indicate that coupling between neuronal and fMRI responses is neither empirically nor mechanistically consistent across the brain.

Self-expandable metal stent placement for the palliation of malignant gastroduodenal obstruction: experience in a large, single, UK centre.

AIM: To assess the technical success rate, and evaluate the clinical outcome, length of hospital stay, and cost of palliative gastro-duodenal stenting in a single-centre. MATERIALS AND METHODS: Eight-seven patients referred for insertion of a gastroduodenal stent between April 1999 and April 2004 were recruited to a non-randomized, before and after intervention study performed in a single centre. Demographic data, diagnosis and symptoms along with clinical and technical outcomes were recorded. RESULTS: The technical success rate was 84/87 (96.6%), with inability to traverse the stricture in three patients. No immediate complications were demonstrated. There was marked improvement after stent placement with resolution of symptoms and commencement of dietary intake in 76 patients (87%). Stenting resulted in improved quality of life as reflected by an increase in Karnofsky score from 44/100, to 63/100 post-procedure. Late complications included perforation (n=1), migration (n=1) and stent occlusions due to tumour ingrowth/overgrowth (n=7; mean 165 days). Mean survival was 107 days (range 0-411 days). Median hospital stay post-stent placement was 5.5 days, (range 1-55 days) with a majority of patients (75%) discharged home. The mean cost of each treatment episode was 4146 pounds ($7132 $US, 6,028 EUROS). CONCLUSION: The present series confirms that combined endoscopic and radiological gastroduodenal stenting is a highly favourable treatment for patients with inoperable malignant gastric outlet obstruction. The results suggest that this minimally invasive procedure has a very high technical success rate, whilst at the same time providing excellent palliation of symptoms with improved quality of life in the majority of patients.

Mapping the effects of the selective dopamine D2/D3 receptor agonist quinelorane using pharmacological magnetic resonance imaging.

Dopamine agonists with a high affinity for D2 and D3 receptors have a biphasic effect on rodent locomotion, inducing hypolocomotion at low doses and hyperlocomotion at higher doses. Controversy surrounds the role of the D3 receptor in mediating the hypolocomotor response to low agonist doses. This study examines patterns of neuronal activation induced by varying doses of the D2/D3 receptor agonist quinelorane using blood oxygen level dependent (BOLD) pharmacological magnetic resonance imaging (phMRI), and compares them with corresponding behavioural responses. Quinelorane (3 microg/kg) induced hypolocomotion in rats naive to the testing environment, and in phMRI experiments increased neuronal activity within the anterior olfactory nuclei, nucleus accumbens and islets of Calleja, regions containing a high density of D3 receptors. A 30 microg/kg dose of quinelorane resulted in biphasic locomotor effects, with initial hypolocomotion followed by sustained hyperlocomotion. phMRI indicated that this higher dose increased cerebral activity within limbic and olfactory regions, as did the lower drug dose, but induced additional activation in the caudate-putamen and globus pallidus, areas dense in D2 receptors but containing few D3 receptors. The more restricted pattern of activation at low agonist doses and close temporal relationship between behavioural and BOLD signal responses to quinelorane suggest that those nuclei most dense in D3 receptors play a key role in mediating the hypolocomotor effects of quinelorane. However, the presence of D3 receptors in activated brain regions may be coincidental, and further studies are required to show definitively which class of receptors mediates agonist-induced hypolocomotion. In contrast, the activation of D2 receptors within the striatum appears necessary for quinelorane-induced hyperlocomotion.

Duodenal obstruction by gallstones (Bouveret's syndrome): a review of the literature.

Bouveret's syndrome, first described in 1896, is gastric obstruction by a gallstone following a cholecystoduodenal fistula. Endoscopy is the mainstay of diagnosis, but radiographic examination such as upper gastrointestinal contrast series and abdominal radiography can also contribute to the diagnosis. Diagnosis by computed tomography and ultrasonography has also been described. The syndrome can be diagnosed and treated endoscopically, with stone extraction or mechanical lithotripsy. Extracorporeal shockwave lithotripsy has also been used successfully. Surgery is required in over 90% of cases, with mortality rates ranging from 19% to 24%. One-stage and two-stage procedures have been described, including enterolithotomy, cholecystectomy, and fistula repair, no convincing data are available to show which of these two approaches provides a better outcome. Although the condition is rare, Bouveret's syndrome should be considered in elderly patients with a history of chronic cholecystitis who present with pain, vomiting or haematemesis.

A double-blind randomised, placebo-controlled trial evaluating the influence of oral long-acting muscle relaxant (Mebeverine MR), and insufflation with CO(2) on pain associated with barium enema.

Previous investigators have shown significant benefit using CO(2) for bowel insufflation. Others have suggested that the long-acting smooth muscle relaxant, Mebeverine, may be of benefit. We subjected this to a randomised double-blind trial. A total of 181 outpatients were randomised to receive either Mebeverine or placebo as pre-medication, and either air or CO(2) for bowel insufflation, thus creating four treatment groups. Visual-analogue lines were used to record pain scores before, during, and up to 8 h following the enema. All groups showed increased pain scores during the enema, with peak pain scores at the end of the examination, falling to baseline scores by 8 h. Patients receiving the combination of C0(2) and placebo had significantly lower pain scores at 1 and 4 h ( P=0.00 and P=0.014, respectively; Kruskal-Wallis test) compared with all other groups. Having Mebeverine as a pre-medication did not significantly lower pain scores compared with placebo, and decreased the amount of benefit received from the CO(2). We confirm that CO(2) is of benefit in decreasing pain during barium enema, and we recommend its routine use to improve the comfort of patients. Mebeverine is not of benefit, and its use as a pre-medication for enemas is not recommended.

Interferential therapy: lack of effect upon experimentally induced delayed onset muscle soreness.

This study was designed to assess the analgesic effects of interferential therapy (IFT) on experimentally induced muscular pain under randomized, double-blind, placebo-controlled conditions. After ethical approval and written consent were obtained, 40 healthy human volunteers (20 males: 20 females) aged 18-25 years were recruited and randomly assigned to one of four experimental groups (n = 10 per group: male = female): IFT 1, IFT 2, control or placebo. Delayed onset muscle soreness (DOMS) was induced in the elbow flexors of the non-dominant arm of each subject using a single bout of eccentric exercises to exhaustion. Measurements of isometric peak torque, resting angle, mechanical pain threshold and visual analogue scales were performed at set time points. Treatment was applied for 30 min daily over the biceps brachii muscle, for five consecutive days, according to group allocation. IFT 1 received 10-20 Hz, whilst subjects in IFT 2 were treated with 80-100 Hz (bi-pole; carrier frequency: 4 kHz; pulse duration: 125 microseconds). For the placebo group, the procedure was identical to that in the active treatment groups; however, no interferential current was delivered. The control group received no treatment. No significant between group difference was identified at any time point (P > or = 0.14). However, some inconsistent, yet significant differences in daily treatment effects, interactive effects and effects over time were detected. Based on the results of this study it can be concluded that application of IFT at the parameters used here, had no overall beneficial effect on DOMS.

Therapeutic ultrasound and wound closure: lack of healing effect on x-ray irradiated wounds in murine skin.

OBJECTIVE: To evaluate the efficacy of ultrasonography as a therapeutic agent in wound healing. DESIGN: Randomized, controlled trial. SETTING: University animal laboratory. ANIMALS: Male BALB/c mice randomly allocated to 5 groups. INTERVENTIONS: In group 1, mice were left untreated; in groups 2 through 5, a well-defined area on the dorsum was exposed to 20Gy x-ray irradiation. Seventy-two hours postirradiation, all mice were anesthetized by inhalation (isoflurane anesthetic) and a 7 x 7mm area wound made on the dorsum. All wounds were videotaped alongside a marker scale 3 times weekly until closure was complete. Mice in groups 4 and 5 were treated with pulsed therapeutic ultrasound for 5 minutes, 3 times weekly at 1 and 3MHz, respectively (intensity, 0.5W/cm(2)); mice in group 3 received placebo ultrasound. Subsequently, the area of each wound was measured from video by using an image analysis system. MAIN OUTCOME MEASURE: Wound closure as a fraction of day zero. RESULTS: Irradiation caused a significant (p < .01) delay in the rate of wound closure by day 11. However, neither placebo ultrasound nor treatment at 1 or 3MHz affected the closure rate. CONCLUSION: These findings provide little evidence that 1 or 3MHz ultrasound applied to a radiation-impaired wound stimulates wound closure in mice.

The effect of three electrotherapeutic modalities upon peripheral nerve conduction and mechanical pain threshold.

The current study was designed to examine the neurophysiological and hypoalgesic effects of three types of electrical stimulation. Following approval by the University's Research Ethical Committee, healthy volunteers (n=40; 20 males and 20 females; age 20-40 years; mean age 26.18 years) were recruited and screened for contraindications. Subjects were randomly allocated in equal numbers to the following groups: control, transcutaneous electrical nerve stimulation (TENS; 150 Hz, 125 micros), interferential therapy (IFT; 150 Hz, 125 micros) or action potential stimulation therapy (APS; 153 Hz, 6.4 ms). All treatments were applied under double-blind conditions for 15 min over the course of the median nerve in the subject's right forearm. Antidromic median nerve compound action potentials (CAPs) were recorded pretreatment, immediately post-treatment (i.e. at 15 min) and then at 25, 35 and 45 min. Immediately following CAP recording, mechanical pain threshold (MPT) was recorded from two sites on the palmar surface of the right hand. Statistical analysis showed significant differences between groups for peak to peak amplitude (PPA) at 25, 35 and 45 min (Kruskal-Wallis: P=0.01, 0.01 and 0.02). Mann-Whitney U-tests indicated a significant increase in PPA in the IFT group compared with all other groups at 25 and 35 min and compared with the TENS and APS groups at 45 min. No significant differences were found for the MPT data. This study has therefore demonstrated that none of the aforementioned modalities produced a significant hypoalgesic effect; however, IFT produced a significant change in PPA compared with TENS and APS.

Low intensity monochromatic infrared therapy: a preliminary study of the effects of a novel treatment unit upon experimental muscle soreness.

BACKGROUND AND OBJECTIVE: The current study (for which ethical approval was obtained) sought to assess the effect of low intensity monochromatic infrared therapy (LIMIRT) on experimentally induced delayed onset muscle soreness (DOMS). STUDY DESIGN/MATERIALS AND METHODS: Healthy volunteers were recruited (n = 24, 12M:12F) and randomly allocated under strict double blind conditions to one of three experimental groups (n = 8, 4M:4F): Control, Placebo, or Treatment (840 nm; 3.0 J cm(-2), pulse frequency 1 kHz). DOMS was induced in a standardised manner in the biceps brachii of the nondominant arm. Subjects attended on 5 consecutive days during which the degree of pain and functional impairment was assessed. RESULTS: Analysis of results by using nonparametric Freidman and Kruskal-Wallis H tests (with relevant post hoc tests) revealed significant differences (P < 0.05) between Control and LIMIRT treatment groups for pain and tenderness scores. Despite trends in favour of the Treatment group, analysis failed to show any significant differences between the LIMIRT treatment and Placebo groups for all variables except mechanical pain threshold points 3-6 on day 2. CONCLUSION: The results of the current study suggest that LIMIRT is ineffective in the management of DOMS at the parameters investigated.

Transcutaneous electrical nerve stimulation (TENS): the effect of electrode placement upon cutaneous blood flow and skin temperature.

In the current study the effect of electrode placement on cutaneous blood flow and skin temperature were assessed using laser Doppler flowmetry. Following approval from the University's ethical committee, 30 subjects were recruited (15 male: 15 female) and randomly assigned to a control or one of two treatment groups (n=10 all groups). TENS was applied either over the median nerve or to the Hegyu acupuncture point (L.I.4) for 15 minutes. Blood flow and skin temperature data were recorded during TENS and for 15 minutes post TENS. Analysis of results showed significant differences between groups for cutaneous blood flow (p=0.0001; repeated measures ANOVA). There was a significant increase in blood flow in the TENS median nerve group compared with the other two groups during TENS application. No significant changes in skin temperature were observed between groups. This study demonstrates that the effect of TENS upon cutaneous blood flow is dependent upon electrode placement sites.

Monochromatic infrared irradiation (890 nm): effect of a multisource array upon conduction in the human median nerve.

OBJECTIVE: Antidromic conduction studies in the human median nerve were used to assess the neurophysiological effects of irradiation of the skin overlying the nerve using a novel treatment unit comprising a multisource monochromatic infrared diode array (Equilight, Denver, CO). MATERIALS AND METHODS: Healthy human volunteers (n = 40) were recruited and randomly allocated to one of four groups: control, placebo, or one of two treatment groups (1.7 and 4.0 J/cm2). After baseline recordings of negative peak latency (NPL) were completed on the nondominant arm, subjects were treated according to group allocation. Recordings were subsequently repeated at 5-min intervals over a 45-min period. RESULTS: Analysis of negative peak latency difference scores (ANOVA) demonstrated significant differences in NPL between groups and over time (p < 0.05). While in the control and placebo groups NPL values remained relatively stable, in the two treatment groups such values decreased marginally, with the greatest effects observed in the 4.0 J/cm2 group (e.g., at 5 min, differences in NPL [mean +/- SEM]: control group, 0.02+/-0.03 msec; treatment group 2, 4 J/cm2, -0.07+/-0.03 msec). Similar significant differences were observed in skin temperature; correlation analysis indicated a weak (but expected) positive linear relationship between skin temperature and nerve conduction velocity (r = 0.125). CONCLUSION: These results suggest that irradiation at the parameters and under the conditions used here produce a direct neurophysiological effect. The magnitude of such effects are in keeping with previous findings using single source arrays at higher radiant exposures or thermal effects of the treatment unit.

Effect of acupuncture upon experimentally induced ischemic pain: a sham-controlled single-blind study.

OBJECTIVE: To investigate the hypoalgesic effect of true and sham acupuncture upon experimentally induced ischemic pain. DESIGN: Human volunteers (n = 60) were required to attend two sessions for pain induction using a submaximal effort tourniquet technique; on the first occasion, baseline pain scores were recorded and on the second, 48 hours later, subjects were randomly allocated to one of five groups: Control, Treatment Groups 1 or 2, or Placebo Groups 1 or 2. SUBJECTS: Healthy human volunteers. INTERVENTION: In all the Treatment and Placebo Groups, subjects received some form of needle acupuncture 15 minutes before, and 5 minutes during, the pain induction procedure on the second day. Treatment Group 1 received acupuncture on acupuncture points situated distal to the tourniquet, whereas Treatment Group 2 received acupuncture on acupuncture points situated proximal to the tourniquet. In Placebo Groups 1 and 2, subjects received 'sham' acupuncture either on nonacupuncture points (Placebo Group 1) or on acupuncture points (Placebo Group 2) using (standardized) minimal levels of stimulation. A licensed acupuncturist who was not involved in data collection and analyses carried out all treatments. OUTCOME MEASURES: Pain was assessed using a computerized visual analog scale (VAS) and a McGill Pain Questionnaire (MPQ). RESULTS: Analysis of VAS scores using ANOVA revealed no significant differences between groups (e.g., VAS sum of differences data (mean +/- SEM): Treatment Group 1: 90+/-47, Treatment Group 2: 187+/-56, Placebo Group 1: 152+/-40, Placebo Group 2: 121+/-42, CONTROLS: 46+/-24, p>0.05). Analysis of MPQ percentage difference scores using one-way ANOVA revealed some isolated effects in the subjective descriptors and the Pain Rating Index, both for Treatment Group 2 and Placebo Group 2, proving them superior to any of the other groups. CONCLUSION: The results of the study provide no convincing evidence for a superior hypoalgesic effect of acupuncture compared with "sham" procedures on this model of experimental pain.

The effect of high- and low-frequency transcutaneous electrical nerve stimulation upon cutaneous blood flow and skin temperature in healthy subjects.

The reported non-analgesic effects of transcutaneous electrical nerve stimulation (TENS) include alterations to the local circulation; however, research in this area has produced equivocal findings. In the present study, the effect of low- (4 Hz) and high-frequency (110 Hz) TENS on forearm skin blood perfusion was assessed using laser Doppler flowmetry. The effect on skin temperature was also assessed using a skin thermistor. Thirty healthy human volunteers were recruited and randomly assigned to a control or one of the two treatment groups. TENS was applied to the skin overlying the median nerve under double-blind conditions for 15 min. Blood flow and skin temperature readings were recorded pre-TENS, during TENS application and continued for 15 min post-TENS application. Analysis of results showed significant increases in blood perfusion during the treatment period in the low-frequency group when compared to the other two groups (P = 0.0106; ANOVA). No significant changes in skin temperature were observed. The results of this study demonstrate that low-frequency TENS produces a local increase in cutaneous blood flow.

A controlled study on the effects of transcutaneous electrical nerve stimulation and interferential therapy upon the RIII nociceptive and H-reflexes in humans.

OBJECTIVE: To study the effect of transcutaneous electrical nerve stimulation (TENS) and interferential therapy (IFT) upon the RIII nociceptive reflex and H-reflex. DESIGN: Double-blind conditions. PARTICIPANTS: Seventy healthy subjects were randomly allocated to one of seven groups (n = 10 per group): Control, TENS 1 (5 Hz), TENS 2 (100 Hz), TENS 3 (200 Hz), IFT 1 (5 Hz), IFT 2 (100 Hz), IFT 3 (200 Hz). INTERVENTION: In the treatment groups, stimulation was applied over the right sural nerve for 15 minutes. MAIN OUTCOME MEASURES: Ipsilateral RIII and H-reflexes were recorded before treatment, immediately after treatment, and subsequently at 25, 35, and 45 minutes. Subjects rated the pain associated with the RIII reflex using a computerized visual analogue scale (VAS). RESULTS: Statistical analysis using ANOVA showed no significant differences between baseline and posttreatment measurement for RIII reflex, H-reflex, or VAS data. CONCLUSION: These results suggest that neither type of electrical stimulation (TENS or IFT) affects the RIII or H-reflexes, at least using the parameters and application time in this study.

The effect of interferential therapy upon cutaneous blood flow in humans.

The aim of the current controlled and blinded study was to investigate the effect of various interferential current frequencies upon cutaneous blood flow in humans using laser Doppler flowmetry, in an attempt to define the physiological mechanisms involved. Following approval from the university's ethical committee, 50 healthy volunteers (25 male, 25 female; age 18-34 years) were randomly allocated into one of five experimental groups: (i) control; neither suction nor interferential current was applied, (ii) placebo; suction only was applied, (iii) IFT 1; 10-100 Hz beat frequency applied, (iv) IFT 2; 80-100 Hz beat frequency applied, and (v) IFT 3; 10-20 Hz beat frequency applied. In the IFT groups, interferential currents were applied through four suction electrodes positioned to target the quadriceps femoris muscle. The following parameters were used in all IFT groups: 125 micros pulse duration, 4 kHz carrier frequency and a 6/6 sweep. In IFT groups 1 and 2 only, the rotating vector system was made active. Ambient and skin temperatures were measured concomitantly. Repeated-measures ANOVA showed a significant difference between groups (P=0.0361) and over time (P=0.0001) for blood flow data; one-factor ANOVA showed a significant increase in blood flow in the IFT 3 group (10-20 Hz) when compared to all experimental groups at 12 min (P=0.0156). In addition, at 21 min, there were significant differences between the IFT 3 group and all other groups except control (P=0.0213). Statistical analysis of skin temperature data demonstrated significant differences over time (P=0.0001) and a significant interactive effect (P=0.0022), with no significant differences observed between groups. These findings provide some evidence of a putative vasodilatory effect caused by interferential current therapy when applied through suction electrodes at a modulated frequency of 10-20 Hz.