Motor unit synchronization of the vasti muscles in closed and open chain tasks

Objectives: To investigate motor unit synchronization between medial and lateral vasti and whether such synchronization differs in closed and open chain tasks. Design: Electromyographic recordings of single motor unit action potentials were made from the vastus medialis obliquus (VMO) and multiunit recordings from vastus lateralis during isometric contractions at 30 degrees of knee flexion in closed and open chain conditions. Setting: Laboratory. Participants: Five volunteers with no history of knee pain (age, 30 +/- 3.32y). Interventions: Not applicable. Main Outcome Measure: The degree of synchronization between motor unit firing was evaluated by identifying peaks in the electromyographic averages of the vastus lateralis, triggered from motor unit action potentials in the VMO, and the proportion of power in the power spectral density of the triggered average at the firing frequency of the reference motor unit. The proportion of cases in which there was significant power and peaks in the triggered averages was calculated. Results: The proportion of trials with peaks in the triggered averages of the vastus lateralis electromyographic activity was greater than 61.5% in all tasks, and there was a significantly greater proportion of cases where power in the spectrum was greater than 7.5% (P = .01) for the closed chain condition. Conclusions: There was a high proportion of synchronized motor units between the 2 muscles during isometric contractions, with evidence for greater common drive between the VMO and vastus lateralis in closed chain tasks. This has implications for rehabilitation because it suggests that closed chain tasks may generate better coordination between the vasti muscles.

Predictors of responsiveness to physiotherapy management of cervicogenic headache

A recent randomized controlled trial tested the effectiveness of therapeutic exercise and manipulative therapy on 200 subjects with cervicogenic headache. Although treatments were efficacious, 25% of patients did not achieve a clinically acceptable outcome - 50% reduction in headache frequency This study aimed to identify predictors from variables in subjects' demographics and headache history which might identify those who did or did not achieve a 50-79% or 80-100% reduction in headache immediately after the active treatments and 12 months postintervention. The results revealed no consistent pattern of predictors, although the absence of light-headedness indicated higher odds of achieving either a 50-79% [odds ratio (OR) = 5.45) or 80-100% (OR = 5.7) reduction in headache frequency in the long term. Headaches of at least moderate intensity, the patient's age and chronicity of headache did not mitigate against a successful outcome from physiotherapy intervention.

The relationship of cervical joint position error to balance and eye movement disturbances in persistent whiplash

Cervical joint position error (JPE) has been used as a measure of cervical afferent input to detect disturbances in sensori-motor control as a possible contributor to a neck pain syndrome. This study aimed to investigate the relationship between cervical JPE, balance and eye movement control. It was of particular interest whether assessment of cervical ME alone was sufficient to signal the presence of disturbances in the two other tests. One hundred subjects with persistent whiplash-associated disorders (WADs) and 40 healthy controls subjects were assessed on measures of cervical JPE, standing balance and the smooth pursuit neck torsion test (SPNT). The results indicated that over all subjects, significant but weak-to-moderate correlations existed between all comfortable stance balance tests and both the SPNT and rotation cervical ME tests. A weak correlation was found between the SPNT and right rotation cervical JPE. An abnormal rotation cervical JPE score had a high positive prediction value (88%) but low sensitivity (60%) and specificity (54%) to determine abnormality in balance and or SPNT test. The results suggest that in patients with persistent WAD, it is not sufficient to measure ME alone. All three measures are required to identify disturbances in the postural control system. (C) 2005 Elsevier Ltd. All rights reserved.

Uso de estimulación eléctrica medular en el manejo de síndrome doloroso regional complejo: revisión sistemática

La estimulación eléctrica medular (EEM), es una técnica mínimamente invasiva, segura, con pocos efectos secundarios y resultados favorables en patologías crónicas asociadas a dolor severo de difícil manejo, tal como es el caso del Síndrome Doloroso Regional Complejo (SDRC). La evidencia actual señala beneficios en esta patología particular, motivo por el cuál es de interés hacer una revisión actualizada sobre la EEM en SDRC.

Does this case hold the answer to one of the worse types of pain in medicine--that of loin pain haematuria syndrome (LPHS)

A patient with loin pain haematuria syndrome suffering chronic throbbing pulsing pain overlaid with prolonged periods of incapacitating colic and overnight vomiting was presented 10 months following diagnosis. Ultrasound was normal. No renal or ureteral stones, or filling defects were seen on CT. At cytoscopy, bladder and urethra were normal, and bloody urine effluxed from the left ureteric orifice. The ureters were normal at diagnosis, and developed new abutting non‐penetrating calcifications by 8 months. Pain episodes of complete incapacitating intensity of 2–4 h duration were reduced to 10 min with 5 mg crushed tadalafil administered at onset. If tadalafil was delayed to after onset, the original course of agony resulted. Daily tadalafil reduced loin pain intensity, but not the exacerbations. Tadalafil efficacy may indicate that the pain exacerbations are due to spasm of ureter smooth muscle. 5 mg tadalafil taken at onset alleviated severe loin pain exacerbations in this case of loin pain haematuria syndrome.

Role for protease activity in visceral pain in irritable bowel syndrome

Mediators involved in the generation of symptoms in patients with irritable bowel syndrome (IBS) are poorly understood. Here we show that colonic biopsy samples from IBS patients release increased levels of proteolytic activity (arginine cleavage) compared to asymptomatic controls. This was dependent on the activation of NF-kappaB. In addition, increased proteolytic activity was measured in vivo, in colonic washes from IBS compared with control patients. Trypsin and tryptase expression and release were increased in colonic biopsies from IBS patients compared with control subjects. Biopsies from IBS patients (but not controls) released mediators that sensitized murine sensory neurons in culture. Sensitization was prevented by a serine protease inhibitor and was absent in neurons lacking functional protease-activated receptor-2 (PAR2). Supernatants from colonic biopsies of IBS patients, but not controls, also caused somatic and visceral hyperalgesia and allodynia in mice, when administered into the colon. These pronociceptive effects were inhibited by serine protease inhibitors and a PAR2 antagonist and were absent in PAR2-deficient mice. Our study establishes that proteases are released in IBS and that they can directly stimulate sensory neurons and generate hypersensitivity symptoms through the activation of PAR2.

Activated mast cells in proximity to colonic nerves correlate with abdominal pain in irritable bowel syndrome

BACKGROUND & AIMS: The mechanisms underlying abdominal pain perception in irritable bowel syndrome (IBS) are poorly understood. Intestinal mast cell infiltration may perturb nerve function leading to symptom perception. We assessed colonic mast cell infiltration, mediator release, and spatial interactions with mucosal innervation and their correlation with abdominal pain in IBS patients. METHODS: IBS patients were diagnosed according to Rome II criteria and abdominal pain quantified according to a validated questionnaire. Colonic mucosal mast cells were identified immunohistochemically and quantified with a computer-assisted counting method. Mast cell tryptase and histamine release were analyzed immunoenzymatically. Intestinal nerve to mast cell distance was assessed with electron microscopy. RESULTS: Thirty-four out of 44 IBS patients (77%) showed an increased area of mucosa occupied by mast cells as compared with controls (9.2% +/- 2.5% vs. 3.3 +/- 0.8%, respectively; P < 0.001). There was a 150% increase in the number of degranulating mast cells (4.76 +/- 3.18/field vs. 2.42 +/- 2.26/field, respectively; P = 0.026). Mucosal content of tryptase was increased in IBS and mast cells spontaneously released more tryptase (3.22 +/- 3.48 pmol/min/mg vs. 0.87 +/- 0.65 pmol/min/mg, respectively; P = 0.015) and histamine (339.7 +/- 59.0 ng/g vs. 169.3 +/- 130.6 ng/g, respectively; P = 0.015). Mast cells located within 5 microm of nerve fibers were 7.14 +/- 3.87/field vs. 2.27 +/- 1.63/field in IBS vs. controls (P < 0.001). Only mast cells in close proximity to nerves were significantly correlated with severity and frequency of abdominal pain/discomfort (P < 0.001 and P = 0.003, respectively). CONCLUSIONS: Colonic mast cell infiltration and mediator release in proximity to mucosal innervation may contribute to abdominal pain perception in IBS patients.

Multidisciplinary approach to chronic pain from myofascial pain dysfunction syndrome: A four-year experience at a Brazilian center

Chronic pain is the major complaint of myofascial pain dysfunction syndrome (MPDS) and is a complex problem which involves physical, psychological and social aspects, the etiology of MPDS is multifactorial and the multidisciplinary approach is essential for differential diagnosis and for comprehensive treatment planning, In 1993, the Dental School of Piracicaba-UNICAMP, Brazil, opened a Center for Pain Studies (CPS), staffed by health care providers including, dentists, psychologists, physicians, physiotherapists and phonoaudiologists. The major aims of the CPS are to provide clinical care and to develop basic and applied research, Sixty-two MPDS patients had been admitted to the CPS by 1997, There were 60 females and 2 males, mean age -32.5 years, the mean duration of chronic pain was 48 months. Pain intensity and unpleasantness were measured employing the Visual Analogue Scale, the tendency to develop stress-related diseases was assessed by the Social Readjustment de Scale, There was a mean reduction of chronic pain of 69.89% and 71.78% relative to intensity and unpleasantness, respectively, the experience of clinical attendance at a multidisciplinary center showed the relevance of a team consisting of health care providers from different specialties with well-established aims, completely integrated and sensitive enough to understand the painful complaints of MPDS patients.