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At least 883 records · Page 49Linked to original sources
PubMed1996

Autosomal recessive disorder with muscle contractions resembling neonatal tetanus, characteristic face, camptodactyly, hyperthermia, and sudden death: a new syndrome?

This work describes an autosomal recessive syndrome observed over the past 25 years in 17 newborn babies (8 males, 9 females), from 12 different families in Southern Sardinia. This disorder is evident at birth and is characterized by marked muscular contraction of the facial muscles in response to tactile stimuli or during crying, with trismus and abundant salivation simulating a tetanic spasm. The contractions slowly disappear as the infant calms. There is also neck muscle hypertonia with a tendency to opisthotonus. All patients present facial anomalies such as large face, chubby cheeks, broad nose with anteverted nostrils, and long philtrum. The hands show bilateral camptodactyly. The clinical course in all patients was characterized by marked feeding difficulties and appearance of variable fever at about 38 degrees C, with peaks of irregular hyperthermia of over 42 degrees C, with onset ranging from birth to a few weeks. In some patients these symptoms were accompanied by generalized seizures. Death occurred after a period of a few weeks to some months and coincided with fever above 42 degrees C. Laboratory investigations performed in all of these cases did not give any useful pathogenetic indications. Only patients 10 and 16 are still alive today. Patient 10 is now 14 years old. She presents slow regression of the dystonic symptomatology, while dysthermia and mild psychomotor delay persist.

Chromosome Aberrations↗
PubMed2005

Heading in football. Part 2: biomechanics of ball heading and head response.

OBJECTIVES: Controversy surrounding the long term effects of repeated impacts from heading has raised awareness among the public and the medical community. However, there is little information about the human response to the impacts and what measures can be taken to alter their effect. The objective of the current study was to gain a better understanding of heading biomechanics through the implementation of a numerical model and subsequent investigation of parameters related to heading technique and ball characteristics. METHODS: A controlled laboratory study was carried out with seven active football players, aged 20-23 years who underwent medical screening and were instrumented with accelerometers mounted in bite plates and electromyographic electrodes on the major neck muscle groups. Balls were delivered at two speeds (6 m/s and 8 m/s) as the subjects demonstrated several specific heading manoeuvres. Photographic targets were tracked via high speed video to measure heading kinematics. One subject demonstrating reasonably averaged flexion-extension muscle activity phased with head acceleration data and upper torso kinematics was used to validate a biofidelic 50th percentile human numerical model with detailed representation of the head and neck. RESULTS: Heading kinematics and subject responses were used with a detailed numerical model to simulate impact biomechanics for a baseline heading scenario. Changes to heading techniques and ball characteristics which mitigated head impact response were identified. CONCLUSION: A numerical model combined with biomechanical measurement techniques is an important tool for parametric investigation of strategies to reduce head impact severity via changes in heading technique or the physical properties of the ball.

Adult↗
PubMed2005

A six year prospective study of the incidence and causes of head and neck injuries in international football.

OBJECTIVE: To identify those risk factors that have the greatest impact on the incidence of head and neck injuries in international football. METHOD: A case-control study of players sustaining head and neck injuries during 20 FIFA tournaments (men and women) from 1998 to 2004. Video recordings of incidents were used to identify a range of parameters associated with the incidents. Team physicians provided medical reports describing the nature of each injury. chi2 tests (p< or =0.01) and 95% confidence intervals were used to assess differences in distribution and incidence of injury, respectively. RESULTS: In total, 248 head and neck injuries were recorded of which 163 were identified and analysed on video sequences. The commonest injuries were contusions (53%), lacerations (20%), and concussions (11%). The incidence of all head and neck injuries was 12.5/1000 player hours (men 12.8, women 11.5) and 3.7 for lost-time injuries (men 3.5, women 4.1). The commonest causes of injury involved aerial challenges (55%) and the use of the upper extremity (33%) or head (30%). The unfair use of the upper extremity was significantly more likely to cause an injury than any other player action. Only one injury (a neck muscle strain) occurred as a result of heading the ball throughout the 20 tournaments equivalent to 0.05 injuries/1000 player hours. CONCLUSIONS: Players' actions most likely to cause a head or neck injury were the use of the upper extremity or the head but in the majority of cases these challenges were deemed to be fair and within the laws of the game.

Adolescent↗
PubMed1986

Tremor at rest episodes in unilaterally 6-OHDA-induced substantia nigra lesioned rats: EEG-EMG and behavior.

Twenty male adult Wistar rats were unilaterally lesioned in the substantia nigra (SN) with 6-hydroxydopamine (6-OHDA), and prepared with chronic cortical (ECoG) and neck muscle (EMG) electrodes. Longitudinal study over a period of up to 18 months demonstrated the emergence, in about two-thirds of the rats, of spontaneous repetitive episodes of head and neck tremor during awake at rest, of up to 20 seconds duration each, that were associated with spike and wave-like ECoG activities. These episodes of tremor at rest disappeared during sleep and REM sleep episodes, and also following the i.p. administration of L-DOPA. It is assumed that these tremor at rest episodes are analogous to those reported to occur in primates after experimentally induced dysfunction of the nigro-striatal, extrapyramidal system.

Animals↗
PubMed1995

[Meningoencephalo-myeloradiculitis due to Flavivirus: bi-brachial paralysis and respiratory insufficiency].

3 patients developed rapid onset of fever and nuchal stiffness. Paresis of brachial muscles occurred within 4 days and all patients had respiratory failure that needed mechanical ventilation. At the peak of the disease there were bilateral asymmetrical severe atrophy of brachial, shoulder and neck muscles, cranial nerve pareses and absent or weak deep reflexes in the upper extremities. CSF analyses showed sterile lymphocytic pleocytosis. In 2 cases the patients suffered a tick bite in Switzerland and the third was probably bitten by an insect while opening a package received from Indonesia. Patients had rapid defervescence and serological tests were found to be highly positive for IgM and then IgG ELISA FSME (Frühsommer-Meningoenzephalitis). The patients were ventilated for 2 to 5 weeks before a progressive improvement was seen. However, on follow-up at 12, 18 and 30 months respectively, proximal muscles were still atrophied and quite weak. Our cases underline that: (1) FSME-ELISA results may cross-react with the Japanese and Central European encephalitis virus species; (2) Flaviviruses do induce unusual and preferential long-term paralysis of the upper extremities simulating poliomyelitis; (3) in the 2 patients studied electrophysiologically, there were signs of axonal reinnervation not seen in lower motor neuron syndrome which were important for reinnervation to permit progressive, but late, motor improvement; (4) there is no evidence of extension of the endemic foci of tick-borne encephalitis in Switzerland.

Adult↗
PubMed1995

Neuromechanical regulation of respiratory motor output in ventilator-dependent C1-C3 quadriplegics.

To evaluate the role of phrenic and sternocleidomastoid afferents as alternate sources of inhibitory feedback during mechanical ventilation, we studied five C2-C3 quadriplegics with sensory denervation of the rib cage and diaphragm, six C1-C2 quadriplegics with additional loss of sensory feedback from the neck muscles, and seven normal subjects. We compared the return of inspiratory muscle activity [the recruitment threshold (PCO2RT)] during mechanical ventilation between subject groups after stepwise increases in end-tidal PCO2 (PETCO2) either by increasing the inspired fraction of CO2 (FICO2), decreasing tidal volume (VT; 50 ml/min), or decreasing frequency (f; 1 breath/2 min). Normal subjects were mechanically hyperventilated via a nasal mask until inspiratory activity was undetectable. Efferent input to the sternocleidomastoid was intact at both levels of spinal cord injury, but phasic activity was not evident at the quadriplegics' baseline resting ventilation. The PCO2RT was defined as the level of PETCO2 at which phasic activity of the diaphragm in normal subjects and of the sternocleidomastoid in C1-C2 and C2-C3 quadriplegics recurred. The mean PCO2RT (in response to raising PETCO2 via increased FICO2 while maintaining a high VT and f) was not significantly different (P = 0.6) between normal subjects (43 +/- 3 Torr) and C2-C3 quadriplegics (38 +/- 5 Torr). Both subject groups demonstrated a frequency- and volume-related inhibition, as evidenced by a substantially lower PCO2RT when PETCO2 was raised by reducing either VT or f. In contrast to the C2-C3 quadriplegics, the C1-C2 quadriplegics responded with a similar PCO2RT among the three different mechanical ventilation trials, independent of whether PETCO2 was raised with high VT and f, with reduced VT, or with reduced f. We conclude that feedback from at least some part of the chest wall is required to produce a volume- and frequency-dependent inhibition of inspiratory muscle activity observed during mechanical ventilation.

Adolescent↗
PubMed1986

Brainstem terminations of extraocular muscle primary afferent neurons in the monkey.

The central terminations of afferent nerve fibers from the extraocular muscles of the monkey were investigated by means of transganglionic transport of wheat germ agglutinin-conjugated horseradish peroxidase (WGA/HRP). Following injections of selected extraocular muscles with WGA/HRP, terminal labeling was apparent in the ipsilateral trigeminal sensory and cuneate nuclei. The density of trigeminal projections varied markedly from one rostrocaudal level to the next, being heaviest within the ventrolateral portion of pars interpolaris of the spinal trigeminal nucleus. A second extraocular muscle afferent representation was noted in ventrolateral portions of the cuneate nucleus. This projection was restricted to rostral portions of pars triangularis of the cuneate nucleus, partially overlapping the afferent termination from dorsal neck muscles. It is likely that some of the problems encountered in formulating conclusions regarding the functional role of extraocular muscle proprioception are due to a lack of detailed information of the central termination pattern of muscle afferents. Taken together, the present findings should provide a basis for further anatomical and physiological studies designed to elucidate the role played by extraocular muscle proprioceptors in vision and oculomotor control.

Animals↗
PubMed1996

[The role of cervical input in vestibular compensation].

The role of proprioceptive input from cervical receptors in vestibular compensation was investigated. Vibratory stimulation to the dorsal neck muscle was given to patients with unilateral vestibular lesions. The length of the displacement of the center of gravity, maximum sway length, and sway area increased markedly during vibratory stimulation to the dorsal neck. In patients in whom compensation had been achieved, a position vector to the side of the lesion increased and the center of gravity moved to the side of the lesion. From these results, it can be speculated that cervical input plays an important role in the process of vestibular compensation.

Adult↗
PubMed1996

Abnormal myotonic dystrophy protein kinase levels produce only mild myopathy in mice.

Myotonic dystrophy (DM) is commonly associated with CTG repeat expansions within the gene for DM-protein kinase (DMPK). The effect of altered expression levels of DMPK, which is ubiquitously expressed in all muscle cell lineages during development, was examined by disrupting the endogenous Dmpk gene and overexpressing a normal human DMPK transgene in mice. Nullizygous (-/-) mice showed only inconsistent and minor size changes in head and neck muscle fibres at older age, animals with the highest DMPK transgene expression showed hypertrophic cardiomyopathy and enhanced neonatal mortality. However, both models lack other frequent DM symptoms including the fibre-type dependent atrophy, myotonia, cataract and male-infertility. These results strengthen the contention that simple loss- or gain-of-expression of DMPK is not the only crucial requirement for development of the disease.

Animals↗
PubMedDate not supplied

[Stereotaxic destruction of the interstitial nucleus of Cajal on spastic torticollis].

Intraoperative clinical effects and the results of destruction were demonstrated in 31 patients with various forms of torticollis spastica subjected to operation on the interstitial nucleus of Cajal. The intraoperative clinical complex of symptoms was formed of changes of the toxic and clonic activity of the neck muscles and transient oculomotor and vestibular signs. The favourable postoperative results are evidence of the direct relation of the nuclear structures in the region of the posterior commissure to the mechanisms regulating the posture of the head and neck. Their exclusion may be one of the components of surgical correction of motor abnormalities in patients with torticollis spastica. These operations are more effective in the tonic form of the disease and in prevalence of the rotatory component in the impaired posture of the head.

Adolescent↗
PubMed1990

Effect of preslaughter experience on behaviour, plasma cortisol and muscle pH in farmed red deer.

Three groups of farmed red deer were shot in the field, three groups were slaughtered on the farm and three groups were transported to commercial slaughterhouses. The behaviour of the animals was observed and peripheral plasma cortisol concentrations were measured immediately after slaughter and neck muscle pH was measured 24 hours after slaughter. The deer could be handled and herded without agitation when only one unhindered direction was open to them and nothing in the environment caused alarm. Shallow angled loading ramps were preferable. Deer shot in the field and deer penned without handling had low average plasma cortisol concentrations (less than 7 ng/ml) and a muscle pH less than 5.74 whereas deer which had been herded on the farm, or transported to a slaughterhouse, had high cortisol concentrations (greater than 20 ng/ml) and a muscle pH above 5.74. However, only four of 66 male deer transported to a slaughterhouse had a muscle pH above 6.0, the pH associated with dark cutting meat in red deer.

Abattoirs↗
PubMed1994

[A patient of late-onset nemaline myopathy with mononuclear cell infiltration].

We described a 50-year-old woman with late-onset nemaline myopathy with focal mononuclear cell infiltrates in her muscle biopsy. She developed difficulty in climbing stairs, and elevating her arms for 5 months after the onset of the disease. On admission, neurological examination revealed moderate weakness and atrophy in the proximal limb and neck muscles. Laboratory studies were within normal limits except mildly elevated serum CK and aldolase levels. Electromyography showed myopathic changes in the right triceps and quadriceps muscles examined. A biopsy from the left biceps brachii muscle revealed increased variation in fiber size, with numerous basophilic atrophic fibers. There were some foci of mild mononuclear cell infiltration. Most of basophilic fibers contained nemaline bodies on modified trichrome stain. On electron microscopy numerous nemaline bodies were present in fibers with marked myofibrillar degeneration. Azathioprine and prednisolone administration was not effective to improve her condition. As mononuclear cell infiltration has been occasionally described in the previously reported patients of adult-onset nemaline myopathy, inflammatory process may have some roles in formation of nemaline bodies on the way of acute myofibrillar degeneration.

Female↗
PubMed2002

The three-dimensional structure of a vertebrate wide (slow muscle) Z-band: lessons on Z-band assembly.

The vertebrate muscle Z-band organizes and tethers antiparallel actin filaments in adjacent sarcomeres and hence propagates the tension generated by the actomyosin interaction during muscular contraction. The axial width of the Z-band varies with fibre and muscle type: fast twitch muscles have narrow (approximately 30-50 nm) Z-bands, while slow-twitch and cardiac muscles have wide (approximately 100-140 nm) Z-bands. In electron micrographs of longitudinal sections of fast fibres like those found in fish body white muscle, the Z-band appears as a characteristic zigzag layer of density connecting the mutually offset actin filament arrays in adjacent sarcomeres. Wide Z-bands in slow fibres such as the one studied here (bovine neck muscle) show a stack of three or four zigzag layers. The variable Z-band width incorporating variable numbers of zigzag layers presumably relates to the different mechanical properties of the respective muscles. Three-dimensional reconstructions of Z-bands reveal that individual zigzag layers are often composed of more than one set of protein bridges, called Z-links, probably alpha-actinin, between oppositely oriented actin filaments. Fast muscle Z-bands comprise two or three layers of Z-links. Here we have applied Fourier reconstruction methods to obtain clear three-dimensional density maps of the Z-bands in beef muscle. The bovine slow muscle investigated here reveals a Z-band comprising six sets of Z-links, which, due to their shape and the way their projected densities overlap, appear in longitudinal sections as either three or four zigzag layers, depending on the lattice view. There has been great interest recently in the suggestion that Z-band variability with fibre type may be due to differences in the repetitive region (tandem Z-repeats) in the Z-band part of titin (also called connectin). We discuss this in the context of our results and present a systematic classification of Z-band types according to the numbers of Z-links and titin Z-repeats.

Animals↗
PubMed2002

Early onset chromosome 14-linked distal myopathy (Laing).

A dominantly inherited form of distal myopathy with onset in early childhood was first reported in a 4-generation Australian family in 1995. In the present report we provide further information on the clinical phenotype and natural history of this myopathy, and on the electromyogram and magnetic resonance imaging findings in affected individuals. The pattern of muscle involvement was similar to that in the 'tibial' forms of distal myopathy such as the Finnish (Udd) and Markesbery-Griggs types, with additional involvement of the finger extensors and of some more proximal limb and neck muscles. However, the age of onset was earlier than in these other myopathies and rimmed vacuoles were not found in biopsies from two affected individuals. Evidence of possible anticipation was found in one branch of the family. The gene locus for this myopathy had been mapped to 14q11.2-q13. The linkage region has been refined to a 24 cM region between D14S283 and D14S49 and mutations have been excluded in the PABP2 gene for oculopharyngeal muscular dystrophy which lies within this region.

Adolescent↗
PubMed1991

Causes and signs of temporomandibular joint pain and dysfunction: an electromyographical investigation.

The spontaneous muscular activity of the masseter and two non-masticatory muscles, and their activity under conditions of noise and flickering light, were recorded in 30 patients with mandibular dysfunction, and in 25 control subjects. The mood of the subjects during the investigation, and the possible presence of emotional disturbances was evaluated by means of questionnaires. The enhanced muscular activity of the masseter muscle differentiated patients from the control group, although it does not constitute a pathognomic sign. Unilaterality of complaints, and dysfunctions of differing intensity were not reflected in differential EMG findings. One-fifth of the patients exhibited neck muscle activity occurring simultaneously with the masseter activity. The effect of the applied stimuli on the muscular activity was not homogeneous, leading to activation in some cases and inhibition in others. Symptoms of anxiety could be observed in seven TMJ patients. Anxious patients showed higher levels of muscular activity and emotional irritability during the experiment than non-anxious patients.

Action Potentials↗