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At least 1,063 records · Page 59Linked to original sources
PubMed2001

Extensive sterile abscess in an invasive fibrous thyroiditis (Riedel's thyroiditis) caused by an occlusive vasculitis.

Riedel's thyroiditis is a rare disease determined by an invasive fibrosclerotic transformation of the thyroid gland. It may be one manifestation of multifocal fibrosis with still unknown etiology. Because it mimics carcinoma, a biopsy must be performed to get the correct diagnosis. The condition is self-limiting when confined to the neck. Prognosis depends on the extent of extracervical fibrosclerosis. We present a patient with a huge cervical and mediastinal, unilateral thyroid mass expanding to the aortic curve, which led to tracheal deviation and compression with symptoms of stridor and dyspnea. These symptoms continued under a course of high-dose steroids; thus an operation was necessary to relieve the airway obstruction and limit inflammation. Intraoperative and pathological findings showed an inflammatory infiltration of the adjacent neck muscles and a sterile abscess caused by an occlusive vasculitis. Therefore, hemithyroidectomy had to be performed instead of a local limited resection.

Abscess↗
PubMed1997

[Improving the design of an alloplastic epithelialized tracheal prosthesis].

Replacement of the tracheal conduit remains an unresolved problem. The microporous material expanded polytetrafluorethylene (ePTFE) is suitable for tracheal reconstruction. The aim of our study was to improve the limited mechanical properties of this material by incorporating reinforcement elements and to examine the influence of these elements on host incorporation and epithelialization. In so dours ePTFE prostheses were reinforced with lonomer cement and porous high density polyethylene (pHDPE) rings and implanted into the neck muscle of miniature pigs. One of these prostheses was epithelialized by a cell seeding technique and was thus placed into a tracheal defect. Results were examined grossly by endoscopy and than by light and scanning electron microscopy. The shapes of both types of prostheses showed a high stability. The reinforcement elements did not impair bioincorporation or the ability to epithelialize. In vivo interposition of an incorporated and epithelialized prosthesis to a host led to cell differentiation. The improved biomechanical properties of the prostheses waid and the reproducible formation of epitheliums are important advances in the solution of effectively correcting tracheal defects.

Animals↗
PubMed2006

[First experiences in deep brain stimulation for cervical dystonia].

BACKGROUND: Cervical dystonia results in severe disability and cannot be effectively treated with medication. Repeat injections of botulinum toxin into the dystonic neck muscles can relieve the symptoms in most patients. When this treatment fails (mostly due to antibody formation), deep brain stimulation can be considered. PATIENTS AND METHODS: We report our experiences with eight patients who were treated with bilateral deep brain stimulation of the globus pallidus interna for cervical dystonia. The mean observation period was 31 months. RESULTS: Six of eight patients experienced relief from symptoms a few days after the implantation. Improvement of symptoms was a mean of 60% during the 1st year. There were no complications. CONCLUSION: In this and in other studies with small numbers of patients, deep brain stimulation has shown a good effect on cervical dystonia. According to our results, the patients who benefit most are those with no dystonic shoulder involvement and who have a tonic rather than clonic symptomatology. It seems probable that deep brain stimulation will become the therapy of choice for otherwise intractable cervical dystonia.

Adult↗
PubMed2003

The serotonergic system may be involved in the sleep-inducing action of oleamide in rats.

The mechanism underlying the sleep-inducing effect of oleamide, an endogenous fatty acid amide, was studied in rats. Animals implanted with cerebrocortical and dorsal neck muscle electrodes were monitored continuously by electroencephalograph (EEG) and electromyograph (EMG) for 4 h after i.p. or s.c. injection of drugs. Oleamide induced a dose-dependent increase in slow-wave sleep (SWS), a decrease in wakefulness (W) and sleep latency, but had no effect on rapid-eye-movement sleep (REMS). The oleamide-induced increase in SWS was prevented by 5-HT reuptake inhibitors such as fluoxetine or fenfluramine and by agonists at 5-HT(1A) receptors such as buspirone or 8-hydroxy-2-(di- N-propylamino) tetralin (8-OH-DPAT). Moreover, the selective 5-HT(1A) receptor antagonist WAY100635 markedly antagonized the suppression of the oleamide-induced increase in SWS by 8-OH-DPAT. These data provide the first behavioural evidence that the serotonergic system may be involved in the sleep-inducing action of oleamide in rats.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed2004

Effects of three hypnotics on the sleep-wakefulness cycle in sleep-disturbed rats.

RATIONALE: New sleep disturbance model in rats is useful for estimating the characteristics of some hypnotics. OBJECTIVES: The present study was undertaken to investigate the utility of a sleep disturbance model by placing rats on a grid suspended over water using three kinds of hypnotics, that is, short-acting benzodiazepine (triazolam), intermediate-acting benzodiazepine (flunitrazepam) and long-acting barbiturate (phenobarbital). METHODS: Electrodes for measurement of EEG and EMG were implanted into the frontal cortex and the dorsal neck muscle of rats. EEG and EMG were recorded with an electroencephalogram. SleepSign ver.2.0 was used for EEG and EMG analysis. Total times of wakefulness, non-REM and REM sleep were measured from 0900 to 1500 hours. RESULTS: In rats placed on the grid suspended over water up to 1 cm under the grid surface, not only triazolam but also flunitrazepam and phenobarbital caused a shortening of sleep latency. Both flunitrazepam and phenobarbital were effective in increasing of total non-REM sleep time in rats placed on sawdust or the grid, and the effects of both drugs in rats placed on the grid were larger than those in rats placed on sawdust. Measurement of the hourly non-REM sleep time was useful for investigating the peak time and duration of effect of the three hypnotics. Phenobarbital showed a decrease in total REM sleep time in rats placed on the grid, although both triazolam and flunitrazepam were without effect. CONCLUSIONS: The present insomnia model can be used as a sleep disturbance model for testing not only the sleep-inducing effects but also the sleep-maintaining effects including non-REM sleep and REM sleep of hypnotics.

Analysis of Variance↗
PubMed2005

Effects of kava-kava extract on the sleep-wake cycle in sleep-disturbed rats.

RATIONALE: Kava-kava extract may be useful as an herbal medicine for treatment of insomnia and anxiety. OBJECTIVES: The present study was undertaken to investigate the effects of kava-kava extract on the sleep-wake cycle in comparison with that of flunitrazepam using sleep-disturbed rats. METHODS: Electrodes for measurement of electroencephalogram (EEG) and electromyogram (EMG) were implanted into the frontal cortex and the dorsal neck muscle of rats. EEG and EMG were recorded with an electroencephalogram. SleepSign ver.2.0 was used for EEG and EMG analysis. Total times of wakefulness, non-rapid eye movement (non-REM) and REM sleep were measured from 09:00 to 15:00. RESULTS: A significant shortening of the sleep latency in sleep-disturbed rats was observed following the administration of kava-kava extract at a dose of 300 mg/kg, while no effects were observed on the total waking and non-REM sleep time. On the other hand, flunitrazepam showed a significant shortening in sleep latency, decrease in total waking time and increase in total non-REM sleep time. Although the effects of flunitrazepam were antagonized by the benzodiazepine receptor antagonist flumazenil, the effect of kava-kava extract was not antagonized by flumazenil. Kava-kava extract showed a significant increase in delta activity during non-REM sleep in sleep-disturbed rats, whereas a significant decrease in delta power during non-REM sleep was observed with flunitrazepam. Flumazenil caused no significant effect on the changes in delta activity induced by both kava-kava extract and flunitrazepam. CONCLUSIONS: Kava-kava extract is an herbal medicine having not only hypnotic effects, but also sleep quality-enhancement effects.

Animals↗
PubMed2004

Accuracy of spatial localization depending on head posture in a perturbed gravitoinertial force field.

Spatial orientation is crucial when subjects have to accurately reach memorized visual targets. In previous studies modified gravitoinertial force fields were used to affect the accuracy of pointing movements in complete darkness without visual feedback of the moving limb. Target mislocalization was put forward as one hypothesis to explain this decrease in accuracy of pointing movements. The aim of this study was to test this hypothesis by determining the accuracy of spatial localization of memorized visual targets in a perturbed gravitoinertial force field. As head orientation is involved in localization tasks and carrying relevant sensory systems (visual, vestibular and neck muscle proprioceptive), we also tested the effect of head posture on the accuracy of localization. Subjects (n=10) were seated off-axis on a rotating platform (120 degrees s(-1)) in complete darkness with the head fixed (head-fixed session) or free to move (head-free session). They were required to report verbally the egocentric spatial localization of visual memorized targets. They gave the perceived target location in direction (i.e. left or right) and in amplitude (in centimeters) relative to the direction they thought to be straight ahead. Results showed that the accuracy of visual localization decreased when subjects were exposed to inertial forces. Moreover, subjects localized the memorized visual targets more to the right than their actual position, that was in the direction of the inertial forces. With further analysis, it appeared that this shift of localization was concomitant with a shift of the visual straight ahead (VSA) in the opposite direction. Thus, the modified gravitoinertial force field led to a modification in the orientation of the egocentric reference frame. Furthermore, this shift of localization increased when the head was free to move while the head was tilted in roll toward the center of rotation of the platform and turned in yaw in the same direction. It is concluded that the orientation of the egocentric reference frame was influenced by the gravitoinertial vector.

Adolescent↗
PubMed2000

Neurobehavioural effects of experimental isopropanol exposure.

OBJECTIVES: The study investigated the acute effects of isopropanol exposure at the maximum allowable concentration (MAC) level on the performance of neurobehavioural functions. METHODS: In an exposure chamber 20 healthy subjects aged between 21 and 30 years were exposed to isopropanol at a concentration of 400 ppm (Swiss MAC value) for 8 h. A control group of another 20 subjects of the same age range, gender and education as used in a previous study with methylformate were subjected to the same test procedures without exposure. Mood was measured with the profile of mood states (POMS) in the morning, at noon and in the evening. Neurobehavioural performance tests were administered using the Wiener Test System (Wiener reaction test, Stroop, nonverbal learning, Wiener determination test, "Konturtracking" test), and the digit span test of the Neurobehavioural evaluation system (NES2). A test for postural sway was also conducted. During the POMS and the Wiener determination test the electromyography of the forehead and the left neck muscle as well as the pulse were registered. In the morning and evening spirometry (FVC, FEV, MEF and PEF) and odour threshold were measured. RESULTS: Only postural sway in bipedal standing at noon showed stronger deterioration in the exposed than in the control group when compared with the morning values. The evening values of monopedal standing were also more impaired in the exposed than the control group. In the other tests, no solvent effect could be established. CONCLUSIONS: It can be assumed, that, similar to other alcohols, isopropanol affects postural balance. Our results point to such a disturbance, but because it is the only study so far using the MAC value, any conclusions about safety risks would be premature.

2-Propanol↗
PubMed1996

Tympanal hearing in tachinid flies (Diptera, Tachinidae, Ormiini): the comparative morphology of an innovation.

Tympanal hearing organs have been reported only recently for Diptera. All the cases documented so far relate to parasitoid tachinid flies of the ormiine tribe. In the ormiine flies, the presence of tympanal hearing is functionally linked to their reproductive behavior. Indeed, female ormiine flies detect and localize their host, typically singing orthopterans, by hearing their calling songs. The three ormiine fly species investigated here at the comparative level share the key morphological features associated with tympanal hearing. The extent of these structural modifications becomes evident in the light of comparison with the closely related atympanate tachinid Myiopharus doryphorae. We document a series of eight characters that constitute specialized modifications of the ventral prothorax: (1) an inflation of the probasisternum, providing a rigid frame to span the large tympanal membranes; (2) an increased surface area of the prosternal membranes that constitute very thin, corrugated tympanal membranes; (3) a forked, broad presternum with tympanal pits to which the sensory organs directly attach; (4) several modifications of the tracheal system comprising the enlargement of the prosternal air sac, a supplementary tracheal tube to the prosternal air sac accompanied by a subpartioning of the spiracular atrium, and larger mesothoracic spiracles; (5) the presence of two scolopophorous chordotonal organs in the unpartitioned prosternal air sac; (6) stiff cuticular apodemes linking the chordotonal organs to the presternum; (7) reduction in size of the cervical sclerites; and (8) several structural modifications of the prosternal apophyses, creating new attachment sites for neck muscles. This comparative approach brings out differences and similarities of the homologous cuticular structures found on the ventral prothorax of both tympanate and atympanate tachinids. It is proposed that, given the degree of similarity between the ormiine hearing organs, the ormiine tribe is monophyletic, whereby all members of this tribe evolved from a common ancestor, an acoustic parasitoid of a singing orthopteran insect.

Animals↗
PubMed2006

Vestibular evoked myogenic potentials: optimal stimulation and clinical application.

By easily stimulating the ear with loud sound and recording on tonically contracted neck muscles, vestibular evoked myogenic potential (VEMP) test can reflect inner ear function other than the cochlea and semicircular canal. This expands the test battery for clinicians to explore saccular disease, adding a potential usefulness to the sacculo-collic reflex. The ideal stimulation mode for VEMPs is as follows: 95 dB tone bursts, frequency 500 Hz, stimulation repetition rate 5 Hz, rise/fall time 1 ms, plateau 2 ms, binaural stimulation with bilateral recordings. Animal model using guinea pigs has been established, which sets the stage for useful future studies investigating VEMPs in guinea pigs that would appear to resemble human VEMP responses. Clinically, VEMP test has been widely used in central and peripheral vestibular disorders.

Animals↗
PubMed2005

Migraine and the neck: new insights from basic data.

The clinical presentation of pain in patients with migraine showing spread and referral of pain throughout the trigeminal and cervical innervation territories accompanied by hyperalgesia and allodynia indicates a dynamic trigemino-cervical interaction. The physiologic mechanisms may be convergence of trigemino-cervical afferents and central sensitization of trigemino-cervical neurons leading to dynamic neuroplastic changes during migraine. This review highlights the clinical phenotype and mechanisms of how nociceptive input from neck structures of the upper cervical spine are integrated into the trigemino-cervical system. The nociceptive input into the spinal cord also is subject to a modulation by segmental mechanisms in the spinal cord and by inhibitory projections from brain stem structures such as the periaqueductal gray. The functional relevance of these basic mechanisms is discussed with reference to recent studies using neurostimulation of afferent nerves aiming at pain modulation in patients with migraine.

Electric Stimulation Therapy↗
PubMed1988

The effect of infrahyoid-muscle tenotomy on orofacial motor activity in the rat.

The effects of disturbed proprioceptive feedback from the infrahyoid muscles on the control of chewing and drinking were studied in the unrestrained rat. Rats were trained to lick and to eat in a fixed body position in front of a video camera. After training, the left and right sternohyoid, omohyoid and sternothyroid muscles were cut close to the hyoid bone. EMG-wire electrodes were inserted into the superficial masseter, the anterior and posterior digastic and sternhyoid muscles. EMG-recordings were made at the third, the tenth and the eighteenth day after tenotomy. After about a week the cut ends of the muscles became encapsulated in connective tissue and began to reattach to the hyoid bone; in some animals the sternohyoid muscle reattached to the trachea. In the period before reattachment the mean cycle duration for chewing (but not for drinking) increased. After reattachment the mean cycle duration returned to control values. The contraction patterns after tenotomy were similar to those of the controls during chewing and drinking. The mean burst duration of the sternohyoid increased after tenotomy during chewing but not drinking; it decreased in the digastric muscles and did not change in the masseter.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Alterations of muscle activities and jaw movements after blocking individual jaw-closing muscles in the miniature pig.

Although the inactivation or removal of motoneurones and muscles are known to affect development and growth of the craniofacial skeleton and masticatory muscles, the effect of these on functional activity patterns is not clear. The goal of this study was to evaluate the immediate responses of masticatory muscle activities to temporary nerve blocks of individual jaw-closing muscles. Nineteen experiments were made with four miniature pigs (Sus scrofa). Electromyograms of the masticatory muscles and jaw movements were recorded during natural chewing. Then, the function of individual jaw-closing muscles was removed unilaterally by local anaesthesia, and the recording repeated. The results showed a general increase in the activities of the other jaw-closing muscles, particularly those that were synergistic with the blocked muscle in producing lateral movements. Furthermore, the lateral pterygoid showed stronger activity, and accordingly the lateral movement was increased. Digastric muscle activity and the magnitude of jaw opening also tended to increase. Thus, the response to loss of a muscle is a strong, immediate compensation by synergists.

Animals↗
PubMed1975

The cerebral blood distribution in dogs and cats. An anatomical and functional study.

On the basis of corrosion preparations and of microsphere studies, the following characteristics of the canine and feline cerebral circulation were observed. (1) In cats, a greater part of the vertebral arterial blood goes to the brain and it is more specifically restricted to the ponto-medullary and cerebellar structures. These structures received approximately 3 times more microspheres in cats than in dogs. (2) In dogs, an important amount of vertebral blood goes to the neck muscles, and the intracranial vertebral blood supply is spread over a greater area of the brain, including the thalamo-hypothalamic and posterior cortical zone. (3) In cats the thalamo-hypothalamic area receives a greater amount of blood via the common carotid artery than in dogs. (4) In both animal species, the vascular connections between the left and right side of the brain are more extensive in the vertebral than in the carotid bed. However, for either vascular bed, a more important left to right transmission was found in the dog.

Animals↗
PubMed1979

A proposed natural geometry of recovery from akinesia in the lateral hypothalamic rat.

The Eshkol-Wachmann movement notation is used to analyze and describe neurological recovery from the akinesia caused by severe bilateral lateral hypothalamic (LH) damage in rats. Exploratory movement recovers along several relatively independent dimensions which appear successively. First, lateral head scanning movements recover. At about the same time or later, longitudinal (backward-forward) head scans appear. After movements along these two dimensions increase in amplitude and involve the whole body, vertical (dorsal-ventral) head scans with snout contact (along vertical surfaces) typically appear, and increase gradually in amplitude. Later, vertical rearing without snout contact emerges. Recovery proceeds cephalocaudally, as more caudal limb and body segments are recruited along each of the above dimensions separately. LH rats show delayed recruitment of caudal limb and body segments ('strait-jacket phenomenon'). Support of the body and management of limb and body segments' contact with the ground also recover relatively independently, in a proximodistal fashion. In recovery, arrests between bouts of activity become shorter. Movement first becomes organized in relation to the animals' own body, and only much later, in relation to the environment. In each sequence of movement after pronounced immobility, the rat recapitulates the process of recovery; and, any time it starts to move, it repeats the movements at a particular amplitude several times until there is an increase to the next larger size movement ('warm-up' phenomenon). These regularities explain the apparently bizarre stereotyped behavior in partial enclosures ('behavioral traps') seen in LH rats recovering from akinesia. They also explain some aspects of exploration in rats and normal social behavior of wild animals, particularly in situations involving fear and conflict.

Animals↗
PubMed1979

Regional differences in the timing of synapse elimination in skeletal muscles of the neonatal rabbit.

The time course of disappearance of polyneuronal innervation during development was studied electrophysiologically in skeletal muscles of the rabbit. There were differences of up to a week in the estimated time of onset of synapse elimination in various muscles, with a tendency for the process to begin earlier in muscles situated more anteriorly in the body. There were also differences among muscles in the peak rate of synapse loss during maturation, but these differences do not appear to be related to position in the body or to contractile properties of the muscle.

Aging↗