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Effects of muscarine given into the brain of fowls.

1. The effects of muscarine, given intraventricularly, in adult conscious fowls (Gallus domesticus) or microinfused into various brain regions of conscious young chicks, were tested on behaviour, electrocortical activity and respiratory rate. Its effects given intraventricularly or intravenously to anaesthetized fowls were also examined.2. After intraventricular injection, muscarine elicited immediate behavioural and electrocortical arousal; body temperature was unaffected. After a delay of 30-40 min, tachypnoea developed together with postural changes which included partial abduction of the wings away from the trunk, the back and tail becoming horizontal. These effects were prevented by intravenous or intraperitoneal atropine or hyoscine, but not by pempidine or methylatropine, and were potentiated by physostigmine. Hyoscine given intraventricularly or intravenously did not affect electrocortical activity.3. Intraventricular muscarine given to anaesthetized adult fowls produced brief apnoea. On return of respiration, amplitude of respiratory excursion was diminished for about 5 min; tachypnoea did not develop. Blood pressure also rose briefly. With larger doses of intraventricular muscarine, large amplitude electromyographic potentials developed in the dorsal neck muscles followed later by side-to-side neck movements.4. Muscarine given intravenously to anaesthetized adult fowls, raised blood pressure and perfusion pressure in a perfused hind limb, an effect most likely due to secretion of adrenal medullary catecholamines; these pressor effects were prevented by pempidine and phenoxybenzamine. Given directly to the perfused hind limb, muscarine lowered perfusion pressure.5. In young chicks, muscarine microinfused into the diencephalon or myelencephalon elicited intense bilateral electrocortical alerting associated with periods of alternating violent motor activity and quiescence. Microinfusion of muscarine into the telencephalon induced ipsilateral electrocortical desynchronization without affecting behaviour. These effects of muscarine were prevented by intravenous, intraperitoneal or intracerebral hyoscine, but once its effects were established could be antagonized only with difficulty; pempidine did not prevent these effects. Microinfusions of muscarine into the brain did not affect posture, respiration or temperature.

Alkaloids↗

Interaction between the vestibulo-collic reflex and the cervico-collic stretch reflex in the decerebrate cat.

1. Interactions between the sagittal vestibulo-collic reflex (v.c.r.) and the cervico-collic stretch reflex (c.c.r.) have been studied in the neck extensor muscles biventer cervicis (b.c.) in the decerebrate cat. The v.c.r. was evoked by a 'standard' vestibular stimulus consisting of a sinusoidal nose-up, nose-down head movement of 6-8 deg amplitude at 1 Hz. The c.c.r. was evoked by sinusoidal stretching of the b.c. muscles at 1 Hz. The amplitude of muscle stretching, and its phase in relation to head movement, were systematically varied. 2. When muscle stretching was applied in phase with head movement (so that the muscles were stretched as the head moved in the nose-down direction), the gain of the combined (v.c.r. + c.c.r.) reflex in the b.c. muscles increased above that of the v.c.r. If the muscle stretching was applied out of phase with head movement (so that the muscles shortened as the head moved downward), the gain of the combined reflex was reduced to a value below that of the v.c.r. 3. The effects on the gain of the combined reflex varied in proportion to the amplitude of muscle stretching. The gain and phase of the combined reflex is modelled reasonably well by a linear vectorial addition between the v.c.r. and the c.c.r. over a wide range of amplitudes of muscle stretching. The linear summation model contains a proportionality constant K, which may represent a factor by which the two reflexes are 'calibrated' against each other. 4. If one of the b.c. muscles was held at a fixed length and the other stretched sinusoidally, the c.c.r. was evoked only in the stimulated muscle. Vestibular stimulation then summed with the c.c.r in the stimulated muscle, while on the contralateral side the reflex response was the same as that of the v.c.r. alone. It would appear therefore that the motoneurone pools of the b.c. muscles are organized as independent entities without mutually excitatory or inhibitory reflex linkages. This arrangement presumably allows flexibility in the supraspinal control of the b.c. muscles, which are often used either as synergists during sagittal head movement or as antagonists during horizontal or roll movements of the head. 5. The interaction between the v.c.r. and the c.c.r. results in an apparent 'servo-assistance' role for the muscle afferent feed-back from the b.c. muscles, amplifying or attenuating the reflex response of the muscles to a given head movement.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

Ultrasonography of the neck splenius capitis muscle. Investigation in a group of young healthy women.

PURPOSE: To evaluate the reproducibility of real-time ultrasonography as a method for measuring the size of the splenius capitis muscle (SPCM). MATERIAL AND METHODS: Ten right-handed women (non-athletes) aged 19-29 years were studied. Muscle cross-sectional area (CSA), anterior-posterior dimension (APD), and lateral dimension (LD) were measured bilaterally on 2 successive days, twice each day. RESULTS: The coefficient of variation (CV) of CSA was 2.7% between times, and 3.0% between days. No significant correlations were found between muscle CSA and the anthropometric variables (neck girth, height, weight, fat percentage and body mass index). A significant correlation between CSA and the multiple of the 2 linear dimensions (MLD = LD x APD) was found (r = 0.76, p = < 0.01). CSA of SPCM was larger on the dominant side (p < 0.05). CONCLUSION: The results suggest that real-time ultrasonography is a useful method for evaluating the size of the SPCM.

Adult↗

Outcome in juvenile dermatomyositis.

The clinical features, outcome and complications of juvenile dermatomyositis were studied in a tertiary care hospital by retrospective analysis of case records. Nineteen patients were treated over an 11-year period. Median age at diagnosis was 12 years (2.5-16 years). Median duration of disease prior to diagnosis was 12 months (2-96 months). Proximal muscle weakness was seen in all 19 cases, neck muscle weakness in 14, pharyngeal muscle involvement in 5 and respiratory muscle involvement in 3 cases. Heliotrope rash was seen in 9 and Gottrons rash in 8 patients. Myocarditis and GI bleed were seen in 1 each while interstitial lung disease was seen in 2 patients. All except one patient received prednisolone. Methotrexate was used in 13 and azathioprine in 3 patients. Eight patients are in complete remission (CR), 8 partial remission and 2 patients had no response. Complications were calcinosis in 5, contractures in 2, TB in 4 and pyogenic infections in 4 patients. Juvenile dermatomyositis needs to be recognised early and treated aggressively to improve outcome.

Adolescent↗

Temporomandibular pain and dysfunction syndrome associated with generalized musculoskeletal pain: a retrospective study.

Sequential patients seen in a Temporomandibular Joint Clinic were reviewed for evidence of generalized musculoskeletal pain. A greater proportion of patients with myofascial pain dysfunction syndrome than those with other causes of temporomandibular joint pain and complaints of pain outside the jaw in the head and neck region, pain on neck muscle palpation and bilateral symptoms. Demographic and other abnormalities in these patients suggest similarities to fibromyalgia syndrome.

Back↗

Tension-type headache: pain, fatigue, tension, and EMG responses to mental activation.

Twenty patients with tension-type headache (14 chronic and 6 episodic) and 20 group-matched controls were selected for this study. They participated in a 1-hour, complex, two-choice, reaction-time test, as well as 5-minute pretest and 20-minute posttest periods. Subjects reported any pain in the forehead, temples, neck, and shoulders, as well as any feelings of fatigue and tension during the pretest, and every 10 minutes during the test and posttest by visual analog scales. Superficial electromyography was recorded simultaneously from positions representing the frontal and temporal muscles, neck (mostly splenius), and trapezius muscles. The location of pain corresponded to the position of the electrodes, but extended over a larger area. The test provoked pain in the forehead, neck, and shoulders of patients, i.e., pain scores from these regions increased significantly during the test. The pain scores continued to increase posttest. In patients, the EMG response of the trapezius (first 10 minutes of the test) was elevated relative to pretest. In controls, only the frontal muscles showed an EMG test response. Patients showed significantly higher EMG responses than controls in the neck (whole test period) and trapezius (first 10 minutes of the test period). There were significant differences in pain and fatigue scoring between patients and controls in all three periods and in tension scoring posttest. Fatigue correlated with pain, with increasing significance for all locations examined, while tension was mainly associated with the neck pain. The meaning of the variables "tension" and "fatigue" in headache, and their association with recorded muscle activity in various regions is discussed. The EMG response of the trapezius muscle to the test is discussed in comparison with similar responses observed in patients with other pain syndromes.

Adult↗

[Effect of muscle pain on c-fos expression and NADPH-diaphorase activity in the spinal cord].

Capsaicin (Sigma, 5 mg/l ml) was unilaterally injected into dorsal neck muscles (mm. trapezius, splenius) of the cat (n = 6) anesthetized with alpha-chloralose. The laminar distribution of Fos- immunoreactive (Fos-ir) and NADPH-d-reactive neurons was studied in the sections of the cervical and lumbar segments. In comparison to sham operated animals (n = 2), 2 h after capsaicin injection the significant c-fos expression was found throughout the cervical cord (C1 - C8) ipsilaterally and lumbar cord bilaterally (L1 - L7), while the predominant mean number of Fos-ir neurons was detected in the C1 - C4 and L3-L6 segments. In cervical spinal cord, c-fos expression was three times more than in lumbar spinal cord. Dorsal neck noxious stimulation produced widespread c-fos expression in the large and small labeled cells within lamina 1, at the neck of the dorsal horn (lamina V) and also in the medial part of the intermediate zone (lamina VII) where cells of origin of the long crossed and uncrossed descending propriospinal pathways to the lumbar cord were known to be localized. The main accumulations of NADPH-d-reactive cells were registered within the marginal zone (laminae I and II) and medial part of the intermediate zone (lamina VII). Fos-ir neurons were co-distributed with NADPH-d-reactive cells within the marginal zone, and the neck of the dorsal horn, however, double-staining spinal neurons were not registered. These results strongly suggest that the revealed c-fos expression in cervical and lumbar segments depends on the activity of vanilloid receptors of the cervical muscles and confirmed the anatomical coupling of both regions through long propriospinal pathways which may be underlying in the cervico-lumbar nociceptive processing. An influence of the spino-cerebro-spinal loop on modulation c-fos expression in these regions is not excluded also.

Animals↗

Histochemical classification of neck and limb muscle fibers in a turtle, Pseudemys scripta: a study using microphotometry and cluster analysis techniques.

We have attempted to develop an objective, semiquantitative classification of fiber types in turtle neck and limb muscle using microphotometry and multivariate statistical techniques. We first stained serial sections for myosin adenosine triphosphatase (ATPase) (with acid and alkaline preincubation and without preincubation), NADH-diaphorase, and two glycolysis-associated markers, alpha-glycerophosphate dehydrogenase (alpha-GPDH) and glycogen phosphorylase A (GPA). This allowed us to characterize individual muscle fibers in terms of their contraction speed and metabolic properties. Next we used microphotometry to measure the optical density of the reaction product in each fiber, and we subjected the resulting optical density matrix to cluster and discriminant function analyses in order to assign fibers to groups (fiber types) and to determine which stains contribute most to the distinction between groups. As a control, we processed a well characterized mammalian muscle (rat sternomastoid) simultaneously. Our results suggest that both neck and limb muscle in Pseudemys can best be described as falling into three groups: 1) slow oxidative (SO) fibers; 2) fast oxidative glycolytic (FOG) fibers, with relatively high oxidative and glycolytic capacities; and 3) fast glycolytic (Fg) fibers, with low oxidative, low/intermediate alpha-GPDH, and high GPA activities. These three fiber types differ from like-named types in rat muscle both in the pH lability of their myosins and in their metabolic profiles.

Animals↗

Neck proprioception and spatial orientation in cervical dystonia.

Neck muscle vibration is known to influence body orientation and posture during locomotion and stance in normal subjects. To verify the hypothesis that neck proprioceptive input can be misinterpreted in patients with cervical dystonia (CD), lateral continuous vibration was applied to the sternocleidomastoid muscle during both stepping-in-place and quiet stance, with eyes closed. The orienting responses of CD patients were compared with those of normal subjects. Vibration effects on body orientation during stepping and stance were apparently different from normal, since no effects were seen when all patients' data collapsed were analysed. However, while some patients did not respond to vibratory stimuli regardless of the vibrated side, others had a 'good' side, the stimulation of which produced effects on body orientation similar to those observed in normal subjects. Homogeneous groups within the patient population were identified, based on the vibration-induced responses under stepping conditions. The different orienting or postural responses observed in CD patients were correlated with disease-related features such as spontaneous head position, maximum range of voluntary head yaw, presence or absence of a botulinum toxin treatment and disease duration. Our data suggest that, in CD patients, the reference system used in the control of body orientation in space is either refractory to the lateralized proprioceptive neck input or modified such that the input from both sides produces an orientation shift in the same sense. This would depend on the pathogenesis of the disease or on an adaptive process connected to the head abnormal posture. It seems that this refractoriness spreads to both sides of the neck with the advancement of the disease, thereby possibly entraining a progressive shift from a reference system based on the head to a more reliable egocentric reference.

Adult↗

Corticomotor representation of the sternocleidomastoid muscle.

The topography of the cortical motor projection to the sternocleidomastoid (SCM) muscles was investigated in 15 normal subjects using the technique of transcranial magnetic stimulation. Contrary to the long-held view that the representation of the neck muscles in the motor strip is close to that of the face, our findings indicate that the projection to both the ipsilateral and contralateral SCM muscles arises from an area of cortex high up on the cerebral convexity close to the trunk representation and at a comparable level to the sensory representation of the neck in the post-central cortex. The use of shielded intramuscular recordings showed that surface recordings detect activity not only from the SCM muscle but also from the overlying platysma muscle whose cortical representation is lateral to that of the hand muscles. Our findings confirm that the corticomotor projection to the SCM muscle follows both a contralateral monosynaptic pathway, and an ipsilateral pathway, and indicate that the latter pathway may be disynaptic.

Adult↗

A peptide-based immunoassay for antibodies against botulinum neurotoxin A.

Cervical dystonia (CD) is due to neck-muscle spasms that cause pain and involuntary contractions resulting in abnormal neck movements and posture. Symptoms can be relieved by injecting the affected muscle with a botulinum neurotoxin (BoNT, usually type A or type B). The therapeutic benefits are impermanent and toxin injections need to be repeated every 3-6 months. In a very small percentage of patients (less with BoNT/A than with BoNT/B) the treatment elicits blocking anti-toxin antibodies (Abs), which reduce or terminate the patient's responsiveness to further treatment. We have recently mapped (Dolimbek et al., 2006) the CD sera Ab-binding profile using a panel of 60, 19-residue peptides that encompassed the entire H chain sequence 449-1296 and overlapped consecutively by 5 residues. Abs in CD sera bound to one or more of the peptides N25, C10, C15, C20, and C31. This suggested the possibility that binding to these peptides could be used for assay of Abs in CD sera. Data analysis reported here found that Ab binding to these regions showed very significant deviations from the control responses. Of these four peptides, C10 showed the most significant level of separation between patient and control groups (p = 5 x 10(-7)) and the theoretical resolution (i.e., ability to distinguish CD patients from control, see full definition under 'Statistical analysis' in Methods), 84%, was about 4% higher than the least resolved response, C31 (p = 6 x 10(-6), resolution 80%). Since the amounts of Abs bound to a given peptide varied with the patient and not all the patients necessarily recognized all four peptides, there was the possibility that binding to combinations of two or more peptides might give a better discriminatory capability. Using two peptides, C10 plus C31, the resolution improved to 87% (p = 4 x 10(-8)). These two peptides appeared to compliment each other and negate the lower resolution of C31. Combination of three peptides gave resolutions that ranged from 85 (N25 + C15 + C31; p = 2 x 10(-7)) to 88% (C10 + C15 + C31; p = 1 x 10(-8)). Finally, using the data of all four peptides, N25 + C10 + C15 + C31, gave a resolution of 86% (p = 1 x 10(-7)). Although these levels of resolution are somewhat lower than that obtained with whole BoNT/A (resolution 97%; p = 6 x 10(-12)), it may be concluded that the two-peptide combination C10 + C31, or the three-peptide combination C10 + C15 + C31 (affording resolutions of 87 and 88%, respectively) provide a good diagnostic, toxin-free procedure for assay of total specific anti-toxin Abs in BoNT/A-treated CD patients.

Amino Acid Sequence↗

Self-initiating a seated perturbation modifies the neck postural responses in humans.

When seated subjects are submitted to a linear acceleration, reports indicate that the kinematic and electromyographic (EMG) responses of the head-neck system can be modulated with the magnitude of the linear acceleration. There is no evidence, however, that head kinematics or neck EMG activity can be modulated when specific knowledge and active control about the onset of platform acceleration are available. Sixteen seated subjects were given forward linear accelerations in two different conditions nested within subjects: reactive and predictive. In the reactive condition, the acceleration was initiated following a variable delay unknown to the subjects whereas in the predictive condition, subjects manually self-initiated the perturbation. All neck muscle activities were decreased 50-100 ms after platform movement onset in the predictive condition relative to the reactive condition, whereas head and neck peak angular positions and velocities were not different between the two conditions. These results suggest that feedforward control could use the self-generated timing information of platform movement onset to scale the appropriate neck motor output.

Acceleration↗

Central representation and somatotopic organization of the jaw muscles within the facial and trigeminal nuclei of the pigeon (Columba livia).

The location of facial and trigeminal brainstem motoneurons innervating the jaw muscles of the pigeon has been determined, using the technique of retrograde transport of horseradish peroxidase. Trigeminal motoneurons innervating the jaw closing muscles are located within the classically defined main trigeminal motor nucleus, and their organization exhibits approximately a mediolateral somatotopy. Trigeminal neurons innervating the opener muscle of the upper jaw are also located in the main trigeminal motor nucleus, but comprise a dorsomedial subnucleus which is continuous caudally with the dorsal facial nucleus whose neurons innervate the opener muscle of the lower jaw. The Vth and VIIth motor nuclei are thus linked in the rostrocaudal plane. The representations of other head muscles are arranged in a dorsoventral manner within the V-VII motor complex, with the lower eyelid muscle represented most dorsally and the hyoid and superficial neck muscles most ventrally. Jaw closing muscles were well represented in both the Gasserian ganglion and trigeminal mesencephalic nucleus. No such representation was found for either of the jaw opening muscles. The HRP data indicate that the V-VII motor complex in birds is far more extensive than has previously been suggested.

Animals↗

[Influence of below-freezing temperatures on the rate of post-mortem metabolism and the water-holding capacity in prerigor frozen beef muscles (author's transl)].

Prerigor beef is very suitable for the production of "bruehwurst" (frankfurter and bologna type sausages) because of its high waterholding capacity (WHC). This high WHC can be preserved for several months by rapid freezing of prerigor beef either unsalted or salted. In order to elucidate the optimum conditions of frozen storage for the preservation of high WHC, intact beef muscle, ground beef and ground, salted (2% NaC1) beef (neck muscles) were frozen at - 18 degrees or --40 degrees C in a thin layer (0.5-1 cm) 30--60 min after slaugther and stored at various temperatures between --5 degrees and --40 degrees C. The changes of biochemical parameters (content of glycogen and lactate, R-value [it corresponds to ATP concentration] and pH) in the tissue and the WHC of raw and heated muscle homogenates, prepared from the frozen material and containing 2% NaC1, were measured and related to time and temperature of frozen storage. At storage temperature of --18 degrees and --40 degrees C no appreciable biochemical changes occur in intact and ground, unsalted tissue over a period of 10 months. Above 18 degrees C, however, rising temperature causes an increased rate of ATP turnover and glycolysis. In ground muscle higher rates of postmortem metabolism are generally found than in the intact tissue. In prerigor salted and frozen beef a faster drug of ATP concentration (increase of R-value) occurs whereas the breakdown of glycogen to lactate is inhibited. The WHC of raw and heated muscle homogenates depends on time and temperature of frozen storage. As soon as the ATP concentration in unsalted beef falls to a level, at which the onset of rigor mortis occurs, the WHC of homogenates decreases markedly. With beef, ground and salted in the prerigor state and than frozen muscle homogenates are obtained which show always a high WHC even after complete breakdown at ATP during frozen storage. These results have practical consequences with regard to processing of hot-deboned beef.

Adenosine Triphosphate↗

Mitochondrial disorder aggravated by propranolol.

Although there are indications that beta-blockers affect the skeletal muscle in therapeutic dosages, their influence on mitochondrial disorders is unknown. A 52-year-old woman developed double vision, myalgias, muscle cramps, and hip and thigh muscle stiffness. Clinical neurologic examination revealed ptosis, dysarthria, sore neck muscles, weakness and wasting of the thighs, and generally brisk tendon reflexes. Lactate stress testing was significantly abnormal. Needle electromyography was nonspecifically abnormal and myopathic. Muscle biopsy showed mild myopathic changes, target fibers, and a single COX-negative fiber. Probable mitochondrial disorder was diagnosed. The patient had been on 30 mg of propranolol during 7 years for arterial hypertension. Shortly after discontinuation of the drug, her double vision gradually disappeared, myalgias and muscle cramps gradually resolved, and the patient reported an increase in muscle mass on repeated follow-ups. Long-term administration of propranolol may aggravate a mitochondrial disorder. Discontinuation of propranolol may result in a gradual resolution of these adverse reactions.

Adrenergic beta-Antagonists↗