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At least 703 records · Page 39Linked to original sources

PubMed2004

Sex differences in temporal characteristics of descending inhibitory control: an evaluation using repeated bilateral experimental induction of muscle pain.

Little is known about sex differences in the temporal pattern of descending inhibitory mechanisms, such as descending noxious inhibitory control (DNIC). Sex differences in temporal characteristics of DNIC were investigated by measuring pressure pain thresholds (PPTs) over time in the trapezius muscles (local pain areas) and the posterolateral neck muscles (referred pain areas) following repeated bilateral injection of hypertonic versus isotonic saline into both trapezius muscles. Ten females and 11 males received two consecutive bilateral injections, with 15 min interval, of either 5.8% hypertonic saline (0.5 ml in each side for each bilateral injection) or isotonic saline as a control in a randomized manner. Following hypertonic saline injection, the maximal pain intensities of the first and second bilateral injections were significantly higher in females than in males. The PPTs in the trapezius muscles were significantly lower in females than in males. Significantly higher PPTs (hypoalgesia) in men than in women were shown 15 min after the first bilateral injection, and 7.5 and 15 min after the second bilateral injection in the referred pain areas. Importantly, the second bilateral injection failed to further increase the PPTs for both sexes. These results showed that there were sex differences in temporal characteristics of descending inhibition with long-lasting hypoalgesia in men than in women. Repeated noxious muscular stimuli may inhibit further build-up of DNIC, which may reflect a mechanism of plasticity of the descending inhibitory systems following recurrent nociceptive barrage for both sexes.

Adult↗

PubMed2000

Merosin-deficient congenital muscular dystrophy with mental retardation and cerebellar cysts unlinked to the LAMA2, FCMD and MEB loci.

We report a case of congenital muscular dystrophy with secondary merosin deficiency, structural involvement of the central nervous system and mental retardation in an 8-year-old girl from a consanguineous family. She had early-onset hypotonia, generalized muscle wasting, with weakness especially of the neck muscles, joint contractures, mental retardation and high creatine kinase. Muscle biopsy showed dystrophic changes with partial deficiency of the laminin alpha(2) chain. Cranial magnetic resonance imaging revealed multiple small cysts in the cerebellum, without cerebral cortical dysplasia or white matter changes. The laminin alpha(2) chain (6q2), Fukuyama type congenital muscular dystrophy (9q31-q33) and muscle-eye-brain disease (1p32-p34) loci were all excluded by linkage analysis. We suggest that this case represents a new entity in the nosology of congenital muscular dystrophy.

Central Nervous System Cysts↗

PubMed1987

Neurotoxic effects of organophosphorus insecticides. An intermediate syndrome.

Acute neurotoxic effects during the cholinergic phase of organophosphorus insecticide poisoning and delayed neurotoxic effects appearing two to three weeks later are well recognized. We observed 10 patients who had paralysis of proximal limb muscles, neck flexors, motor cranial nerves, and respiratory muscles 24 to 96 hours after poisoning, after a well-defined cholinergic phase. The compounds involved were fenthion, monocrotophos, dimethoate, and methamidophos. Four patients urgently required ventilatory support. The paralytic symptoms lasted up to 18 days. A delayed polyneuropathy later developed in one patient. Three patients died. Electromyographic studies showed fade on tetanic stimulation, absence of fade on low-frequency stimulation, and absence of post-tetanic facilitation, suggestive of a postsynaptic defect. This neuromuscular junctional defect may have been the predominant cause of the paralytic symptoms, with neural and central components contributing to various degrees. Our patients appeared to have a distinct clinical entity (a so-called intermediate syndrome) that developed after the acute cholinergic crisis and before the expected onset of the delayed neuropathy.

Adult↗

PubMed1999

The posterior basal diencephalon of rats enhances expression of an activated state.

STUDY OBJECTIVES: Various ablation studies have implicated the posterior basal diencephalon in the promotion of wakefulness. Although many studies have examined the role of this structure in promotion of cortical arousal, few investigations have attempted to examine its importance in regulation of motor activation (behavioral arousal). In the current study, recordings of freely moving decerebrate rats with and without a posterior basal diencephalon were performed. These studies allowed determination of the behavioral states expressed by the preparations and whether removal of the posterior basal diencephalon completely eliminated expression of both activated state with and activated state without limb movements. DESIGN: Muscle activity was recorded from limb and neck muscles. Eye movements and heart rate were also monitored. The percentage of time spent in various behavioral states and the proportion of limb movements expressed in each of these states were determined. MEASUREMENTS AND RESULTS: Rats with an intact posterior basal diencephalon cycled between all behavioral states. However, they spent most of the recording time in an activated state. In contrast, removal of the posterior basal diencephalon produced rats that spent most of the recording period in a quiescent state. Limb movements were expressed mainly by animals with an intact posterior basal diencephalon, and only when these animals were in the activated state. CONCLUSIONS: The results of this study suggest that the posterior basal diencephalon is required for expression of an activated state and specifically provide evidence for a descending projection from this region required for expression of this state and associated motor activation.

Animals↗

PubMed2005

Toxicoinfectious botulism in commercial caponized chickens.

During the summer of 2003, two flocks of commercial broiler chickens experienced unusually high death losses following caponizing at 3 wk of age and again between 8 and 14 wk of age. In September, fifteen 11-wk-old live capons were submitted to the Iowa State University Veterinary Diagnostic Laboratory for assistance. In both flocks, the second episode of elevated mortality was associated with incoordination, flaccid paralysis of leg, wing, and neck muscles, a recumbent body posture characterized by neck extension, and diarrhea. No macroscopic or microscopic lesions were detected in affected chickens. Hearts containing dotted blood and ceca were submitted to the National Wildlife Health Center in Madison, WI. Type C. botulinum toxin was identified in heart blood and ceca by mouse bioassay tests. Enzyme-linked immunosorbent assay tests on heart blood samples were also positive for type C. botulinum toxin. Clostridium botulinum was isolated from the ceca and genes encoding type C. botulinum toxin were detected in cecal contents by a polymerase chain reaction test. Chickens are less susceptible to botulism as they age, and this disease has not previously been documented in broilers as old as 14 wk of age. Wound contamination by spores of C. botulinum may have contributed to the unusually high death losses following caponizing.

Animals↗

PubMedDate not supplied

[A case of spinal segmental myoclonus and propriospinal myoclonus: a neuroelectrophysiologic analysis].

A 37-year-old male patient with spinal segmental myoclonus and propriospinal myoclonus was described. He was admitted to our hospital because of paroxysmal axial myoclonus, which first appeared one month before. He denied any significant accident such as trauma or fever. Apart from myoclonus, no abnormal findings were observed by physical and neurological examinations, routine laboratory investigations and MRI of the cervical and thoracic spinal cords. The myoclonus consisted of continuous rhythmic contractions of the bilateral thoracal and abdominal muscles. Its frequency was approximately 0.3Hz. The clinical findings were typical of spinal segmental myoclonus. In addition, the myoclonus started in the thoracal muscles and frequently spread up to the neck muscles and down to the leg muscles. The myoclonus disappeared in sleep. Polymyography revealed the following findings: (1) The jerks were found on the bilateral axial muscles including sternocleidomastoid, biceps, triceps, pectoralis major, abdominal muscles and quadriceps. (2) Homologous muscles were activated synchronously. (3) The duration of bursts was variable ranging 100 to 400msec. (4) The jerks in the pectoralis muscle preceded those in other muscles. The latencies of the jerks in the other muscles increased with their distance from pectoralis, based on the linear regression analysis of the onset of jerks in the various muscles. (5) The jerks were induced by tapping or electrical stimulation anywhere on the body including the face, but not by flash or sound. From the above polymyographical findings, the myoclonus seems to originate in the T3 spinal cord and slowly up and down the spinal cord at 0.6-1.6 m/sec, suggesting that it is mediated by the propriospinal tract.

Adult↗

PubMed1998

[Intermediary syndrome in acute malathion poisoning].

BACKGROUND: Acute poisoning by an organophosphorus insecticide is frequently observed in Morocco. We report a case of malathion poisoning complicated by an intermediate syndrome. CASE REPORT: A 42-year-old woman was hospitalized 3 hours after ingestion of 50 g of malathion. Intubation and ventilatory assistance was required due to failing consciousness and bronchial plugging. On day 4, a neurological syndrome suggestive of the intermediary syndrome with diaphragmatic palsy made it necessary to continue ventilatory assistance to day 20. DISCUSSION: The intermediary syndrome occurs 24 to 96 hours after the acute cholinergic phase of organophosphorus poisoning. It consists of an exclusive neuromuscular involvement. The intermediate syndrome is confined to an abnormality of neuromuscular function in specific muscle groups: proximal limb muscles, neck flexors, motor cranial nerves and respiratory muscles, with difficult weaning from respiratory assistance. The intermediary syndrome is quite uncommon. The risk of respiratory failure emphasizes the need for close monitoring in an intensive care setting for at least 96 hours, depending on the intensity of the cholinergic syndrome.

Acute Disease↗

PubMed1979

[Changes of postural tonus produced by unilateral deafferentation of the musculature of the neck in pigeons].

In intact or decerebrate pigeons, unilateral functional deafferentation of the dorsal neck muscles of one side produced a postural asymmetry, characterized by an increase in flexor tonus of the ipsilateral wing and leg and an increase in extensor tonus of the contralateral limbs. This postural asymmetry was just opposite in sign to that described recently in cats, where unilateral section of the cervical dorsal roots C1-C3 produced ipsilateral hypertonia and contralateral hypotonia of the limb extensors. The striking increase in flexor tonus of the wing following deafferentation of the ipsilateral neck extensors contrasts with the decrease in flexor tonus of the wing which occurs after deafferentation of the ipsilateral leg extensors. It appears, therefore, that the proprioceptive input from the neck and that from the leg extensors exert an antagonistic influence on the flexor tonus of the ipsilateral wing.

Afferent Pathways↗

PubMed2005

A novel method for subarachnoid drug delivery in the medullary region of rats.

This study describes a novel method for direct subarachnoid drug delivery to the medullary dorsal horn region of rats, without introducing a catheter. The reliability of the method was demonstrated by a pharmacological validation; that is, morphine administration to the medullary region blocked the nociceptive response to formalin injected in the temporomandibular joint (TMJ) region, an effect that was prevented by co-administration of naloxone. The method proposed offers many advantages over the existing methods for medullary drug delivery with catheter implantation. It is easy to be employed, it does not induce any sign of motor impairment, and it does not require the neck surgery performed to implant a catheter in the medullary dorsal horn region. Therefore, it is a useful method for subarachnoid drug delivery in behavioral trigeminal pain studies, particularly when nociceptive behavioral measures that require normal neck muscle activity to occur, such as head withdraw or head flinch, are evaluated.

Analgesics, Opioid↗

PubMed1975

Optic organ and cervical proprioceptors in maintenance of body equilibrium.

Two experiments were made on the functional correlation between the optic organ and the cervical proprioceptors in maintenance of body equilibrium. Experiment I: The effects of weak and strong electric stimulation of the deep nuchal muscles on changes in optokinetic nystagmus and optokinetic after-nystagmus were examined in adult non-albino rabbits with binocular vision. Experiment II: Experiment I was repeated on rabbits with monocular vision giving optokinetic stimulation moving from the side of the blindfolded eye to that of the open eye and applying only weak electric stimulation to the neck muscles. The results obtained were as follows: (1) Experiment I: Weak electric stimulation of the deep nuchal muscles of rabbits with binocular vision tended to promote optokinetic nystagmus with either no significant change or decrease in optokinetic after-nystagmus. Strong electric stimulation had the opposite effects, i.e., it tended to inhibit optokinetic nystagmus and activate optokinetic after-nystagmus. It also produced abnormal optokinetic nystagmus, such as the inversion phenomenon of optokinetic nystagmus and "optokinetic nystagmus firing". (2) Experiment II: Weak electric stimulation of the deep nuchal muscles of rabbits with monocular vision had similar effects to those in experiment I, but promotion of optokinetic nystagmus was less obvious, while activation of optokinetic after-nystagmus was more marked. In addition, the inversion phenomenon of optokinetic nystagmus developed even on weak electric stimulation. From these results the following conclusions were drawn: (1) The cervical proprioceptors can function in two mechanisms causing promotion and break down of equilibrium of the optokinetic system. (2) The cervical proprioceptors, as an organ of equilibrium, can exert two different actions on the optokinetic eye reflexes, i.e., they can promote optokinetic nystagmus and inhibit optokinetic after-nystagmus.

Animals↗

PubMed1999

The neural substrate of the vestibulocollic reflex. What needs to be learned.

The purpose of this review is to assess the role of short-latency pathways in the vestibulocollic reflex (VCR). First the current knowledge about the disynaptic and trisynaptic pathways linking semicircular canal and otolith afferents with cat neck motoneurons is summarized. We then discuss whether these pathways are sufficient or necessary to produce the responses observed in neck muscles by natural vestibular stimulation and conclude that they are neither. Finally, alternate pathways are considered, most likely involving reticulospinal fibers, which are an important part of the neural substrate of the VCR.

Animals↗

PubMed1992

Decrease in cold tolerance of aged rats caused by the enhanced endogenous adenosine activity.

During severe cold exposure, old rats (24-28 months) were less capable of maintaining their body temperature compared to young rats (3-6 months) due to lower rate of heat production. Single injection of adenosine deaminase (AD) (converts adenosine to inosine) significantly increased thermogenesis in both young and old rats. However, doubling the dose of AD was required for optimal thermogenic response in old rats. In contrast, the similar enhancements in both thermogenesis and cold tolerance were observed in both young and old rats receiving the same optimal doses of specific adenosine receptor antagonists. These results lead to the suggestion that the lower capability of aged rats to withstand cold exposure could be due to an increase in adenosine stimulation because of the decreased endogenous AD activity rather than an increase in adenosine receptor sensitivity. This notion is further supported by the finding that the AD activity in the neck muscle, a key site for shivering thermogenesis, was significantly lower in old rats as compared to their younger counterparts before and after cold exposure.

Adenosine↗

PubMed1998

Quantitative electromyographical changes in cervical dystonia after treatment with botulinum toxin.

Injection of botulinum toxin (BT) into affected neck muscles gives symptomatic relief to patients with cervical dystonia by causing a presynaptic block of acetylcholine release. In a retrospective study of 19 patients, we used the turns-amplitude analysis of the EMG interference pattern for the evaluation of electrophysiological changes as a function of time after BT treatment. EMG was performed immediately before and during injection, and muscles showing abnormally increased activity (> 100 turns/s at rest) were given botulinum toxin A (Oculinum (= Botox)) 40-120 units. A second EMG was done 6-30 weeks later. At attempted rest, the sternocleidomastoid muscle contralateral to the involuntary head rotation showed the most pronounced changes, possibly due to relatively large doses of BT, and the EMG changes were related to the time after BT treatment. Six weeks after treatment the muscle showed decreased turns/s, mean amplitude and ratio (turns/amplitude) at rest. At 30 weeks, turns and mean amplitude reached values as before treatment, while ratio was increased to 175% of the pre-treatment value. This pattern may reflect a reversible and random loss of muscles fibres, due to presynaptic denervation. At maximal voluntary contractions, no correlation was seen between time after BT treatment and quantitative EMG.

Adult↗

PubMed1992

Tension type headache: a neuropsychological and neurophysiological study.

Characteristic personality profiles of patients suffering from either migraine headache (MH) or tension type headache (TTH) have been described in the light of Minnesota Multiphasic Personality Inventory (MMPI). In the present study we evaluated personality profile changes following modifications of the painful symptoms after treatment, through the administration of the MMPI to MH and TTH patients. In TTH patients with no clinical improvement the depression scale scores were higher after 6 months of treatment, whereas in MH patients similar scores were observed before and after therapy, thus suggesting a primary role of depression in the onset of pain in the latter patients. Computerized EMG recording of the neck muscle activity showed different patterns of muscle contraction in resting condition and during stress or maximal muscular activity in patients suffering from TTH as compared to MH patients and normal subjects.

Adult↗

PubMed2004

Convergent and divergent effects of neck proprioceptive and visual motion stimulation on visual space processing in neglect.

Visual motion stimulation as well as neck muscle vibration are known to effectively modulate the subjective body orientation in spatial neglect. However, so far only motion stimulation has been demonstrated to substantially influence size and space distortion in neglect patients. The present study aimed to compare the two stimulation methods with respect to their potentially differential impact on subjective body orientation and on space and size distortion, in five neglect patients showing perceptual distortions. We found comparable beneficial effects during left motion stimulation and left neck vibration for the subjective straight ahead. Additionally, left motion stimulation significantly ameliorated the leftward overextension in size matching, line bisection and distance estimation in all five patients. In contrast, during neck vibration only two patients showed an improvement for line bisection and size estimation and none did so for distance estimation. Since these two patients differed from the others as they had either no visual field defects or a major visual field sparing, we suggest--based on recent anatomical and neuropsychological findings--that neck vibration only tends to improve pure neglect-related visuo-perceptual distortions whereas motion stimulation can additionally improve perceptual distortions in neglect associated with hemianopia.

Adult↗

PubMed2005

Demonstration of the appearance of the paraspinal musculoligamentous structures of the cervical spine using ultrasound.

The application of ultrasound in the imaging of the neck has primarily focussed on anterior structures (e.g., thyroid gland). Structures located on the posterior aspect of the neck have received little attention. This study illustrates the capability of modern ultrasound equipment in visualising the musculoligamentous structures of the neck, particularly the paraspinal musculature. Ten healthy adult volunteers (6 female; 4 male) underwent ultrasound examination of the cervical spine. A standardised technique for transducer placement was adopted and successive images of the neck of each subject were obtained. Spatial compound (extended field of view) images were obtained in subjects using one of two different ultrasound systems. Images of structures produced by ultrasound were compared to those achieved with magnetic resonance imaging in three subjects. Identification of key landmarks aided orientation and identification of structures. The internal architecture of the musculoligamentous structures of the cervical spine, especially the posterior neck muscles, was demonstrated well using ultrasound. Our study showed that modern ultrasound equipment is capable of producing clear images of the posterior cervical spine musculature and certain bony features.

Adult↗

PubMed2002

Effects of cervical traction and exercise therapy in cervical spondylosis.

A randomised clinical trial was conducted in the Department of Physical Medicine, Chittagong Medical College Hospital from July, 2001 to June, 2002. The objectives of the study were to find out the effects of cervical traction (CT) and exercise on the patients with chronic cervical spondylosis. A total of 199 patients with cervical spondylosis were included in the clinical trial. One hundred patients were treated with cervical traction plus exercise and 99 patients were treated with non-steroidal anti-inflammatory drug (NSAID). Posture correction advice was given to all patients. The patients were treated for 6 weeks. There was a marked improvement in both the groups after treatment (P<0.001). But there was nearly significant difference regarding improvement in treatment with CT plus exercise than with NSAID (P = 0.06). The results indicate that the improvement of the patients with chronic cervical spondylosis was more in CT plus exercise than analgesics. So, CT & neck muscle strengthening exercise may have some more beneficial effects than NSAIDs on chronic cervical spondylosis.

Adult↗

PubMed2005

A new shoulder orthosis for paralysis of the trapezius muscle after radical neck dissection: a preliminary report.

Despite recent advances using more conservative approaches, standard classical radical neck dissection is still one of the most frequently performed procedures in head and neck cancer patients who have advanced metastatic neck disease. The trapezius muscle paralysis following division of the spinal accessory nerve results in severe pain and cosmetic disturbance related to malalignment of the shoulder joint. The objective of this study is to report our results with a newly developed orthosis to prevent and correct shoulder dysfunction following standard radical neck dissection. Thirty-four patients who underwent standard radical neck dissection as a part of their surgical treatment from 1997-2002 were rehabilitated by the shoulder orthosis. Beginning 2 weeks after surgery, the patients were allowed to use their orthosis. By using a standard questionnaire, the pain and activity scores were recorded at the 1st, 3rd, 6th and 12th months postoperatively. Six patients were excluded from the study, of whom two succumbed to their disease and four discontinued the use of the orthosis. Of 28 patients included in the study, 20 (72%) were completely pain free within 3 months following the surgery. Four patients (14%) noted their pain level as tolerable, and four patients (14%) reported no considerable gain in the pain threshold and/or physical activity levels. Despite the fact that the active abduction range increased only 5 to 20 degrees , the relief of pain and improved malalignment of the scapula and consequently clavicle and humerus led to functional gains, which increased the patients' endurance. At the end of the study, 23 patients (82%) were able to return to their previous jobs or activity levels. Current preliminary reports suggest that this orthosis can be recommended to prevent significant disability in patients with trapezius palsy due to ablative cancer surgery or other reasons.

Accessory Nerve Injuries↗