Patients with chronic pain after whiplash injury and fibromyalgia patients display exaggerated pain after sensory stimulation. Because evident tissue damage is usually lacking, this exaggerated pain perception could be explained by hyperexcitability of the central nervous system. The nociceptive withdrawal reflex (a spinal reflex) may be used to study the excitability state of spinal cord neurons. We tested the hypothesis that patients with chronic whiplash pain and fibromyalgia display facilitated withdrawal reflex and therefore spinal cord hypersensitivity. Three groups were studied: whiplash (n=27), fibromyalgia (n=22) and healthy controls (n=29). Two types of transcutaneous electrical stimulation of the sural nerve were applied: single stimulus and five repeated stimuli at 2 Hz. Electromyography was recorded from the biceps femoris muscle. The main outcome measurement was the minimum current intensity eliciting a spinal reflex (reflex threshold). Reflex thresholds were significantly lower in the whiplash compared with the control group, after both single (P=0.024) and repeated (P=0.035) stimulation. The same was observed for the fibromyalgia group, after both stimulation modalities (P=0.001 and 0.046, respectively). We provide evidence for spinal cord hyperexcitability in patients with chronic pain after whiplash injury and in fibromyalgia patients. This can cause exaggerated pain following low intensity nociceptive or innocuous peripheral stimulation. Spinal hypersensitivity may explain, at least in part, pain in the absence of detectable tissue damage.

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Abstract.A recently observed lethal congenital defect of purebred Holstein calves is reported. Eighteen genetically related calves were necropsied. One calf had been aborted on gestation day 159, and the others were delivered between day 250 and day 285. Birth weights were reduced. The defect was characterized by shortening of the cervical and thoracic parts of the vertebral column due to multiple hemivertebrae, fused and misshaped vertebrae, and scoliosis. Symmetrical flexures of the carpal joints and the metacarpophalangeal joint in combination with a slight lateral rotation of the phalanges also were present. Similar low-grade arthrogryposis was present in the posterior limbs. Fifty percent of the calves had heart malformation. Other malformations occurred in a few calves. Complex vertebral malformation (CVM) is proposed as the designation for this defect. A genetic etiology is indicated because cases occurred following breeding between genetically related individuals. Two common ancestors were found; both were former elite sires of US Holstein origin. Because of the widespread international use of semen from sires occurring in the pedigrees of affected calves, CVM is expected to occur in several countries.Malformations of the axial skeleton are among the most commonly recorded congenital defects in calves. [3][4][5][6]10,12,14,15 Besides agenesia of caudal vertebrae, torticollis, scoliosis, kyphosis, and spina bifida are the most frequently observed vertebral malformations. Lesions in the cervical and thoracic portions of the spinal column are often associated with arthrogryposis. 4 Although the heritability of these defects generally is unknown, specific inherited malformations of the vertebral column have been reported. The most important of these is the short spine lethal, which has been reported in Holstein, Angus, and Norwegian Østerdal cattle. 4,8,11,13 Around 300 hereditary congenital abnormalities have been reported in cattle. 7 However, surveillance for genetic diseases continuously reveals previously unrecognized diseases. In Denmark, a surveillance system for hereditary diseases in cattle has been in force since 1989. 1 As a part of this program, breeders report suspected cases of hereditary abnormalities, and selected cases are submitted for laboratory examination. Since October 1999, multiple Holstein calves with similar malformations have been reported. To investigate these observations, affected calves were sub- Materials and methodsAffected calves were submitted to the laboratory either directly from the breeder or through a local veterinary surgeon. If alive, calves were euthanized by intravenous administration of pentobarbital sodium. Necropsy was performed on arrival at the laboratory, 1-7 days (x ϭ 3.6 days) after death.Laboratory examination. Necropsy was performed on all calves, and samples for histopathology were taken when tissues were suitable. Samples were obtained from the central and peripheral nervous systems, skeletal and heart muscles, lung, liver, spleen, kidney, adrenal glan...

Quantitative sensory tests are widely used in human research to evaluate the effect of analgesics and explore altered pain mechanisms, such as central sensitization. In order to apply these tests in clinical practice, knowledge of reference values is essential. The aim of this study was to determine the reference values of pain thresholds for mechanical and thermal stimuli, as well as withdrawal time for the cold pressor test in 300 pain-free subjects. Pain detection and pain tolerance thresholds to pressure, heat and cold were determined at three body sites: (1) lower back, (2) suprascapular region and (3) second toe (for pressure) or the lateral aspect of the leg (for heat and cold). The influences of gender, age, height, weight, body-mass index (BMI), body side of testing, depression, anxiety, catastrophizing and parameters of Short-Form 36 (SF-36) were analyzed by multiple regressions. Quantile regressions were performed to define the 5th, 10th and 25th percentiles as reference values for pain hypersensitivity and the 75th, 90th and 95th percentiles as reference values for pain hyposensitivity. Gender, age and/or the interaction of age with gender were the only variables that consistently affected the pain measures. Women were more pain sensitive than men. However, the influence of gender decreased with increasing age. In conclusion, normative values of parameters related to pressure, heat and cold pain stimuli were determined. Reference values have to be stratified by body region, gender and age. The determination of these reference values will now allow the clinical application of the tests for detecting abnormal pain reactions in individual patients.

. Multimodal assessment of pain in the esophagus: a new experimental model. Am