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At least 901 records · Page 50Linked to original sources
PubMed1982

Intercostal muscle activity during sleep in the cat: an augmentation of expiratory activity.

Intercostal-muscle activity (I-EMG) was studied in sleep and wakefulness in ten adult cats. The animals were implanted with electrodes for recording the electroencephalogram (EEG), electrooculogram (EOG), and pontogeniculooccipital (PGO) waves as well as intercostal- and neck-muscle activity. A small-animal pneumotachograph connected to a tracheal cannula was used to monitor respiration. The data were obtained in 87 recording sessions, each lasting 5-6 h. Total EEG power (fast Fourier analysis) and integrated I-EMG activity were computed over consecutive 5.12-sec periods of wakefulness and nonrapid eye movement (NREM) sleep. Cycle-triggered histograms based on 50 breaths were computed also in wakefulness and NREM sleep. I-EMG was classified as expiratory or inspiratory according to when the activity was maximal during the respiratory cycle. Expiratory I-EMG augmented progressively during NREM sleep with the maximal activity occurring just before rapid eye movement (REM) sleep. The mean correlation between total EEG power and expiratory I-EMG for all expiratory muscles was 0.441 (+/- 0.16 SD; n=24). In contrast to the consistent augmentation of expiratory I-EMG, inspiratory I-EMG changes from wakefulness to deep NREM sleep varied within and between muscle groups: in 21% of the cases, activity decreased from wakefulness to NREM sleep; in 16% of the cases, activity increased; in 56% of the cases, activity did not change; and in 7% of the cases, activity increased in only the expiratory phase. We conclude the consistent augmentation of expiratory intercostal muscle indicates an active, NREM sleep-specific respiratory process that may have important implications for lung mechanics in that state.

Animals↗
PubMed1992

Stapedius reflexes to electrical stimulation in the rabbit for the assessment of hearing.

The possibility of using electrically induced stapedius reflexes as a means of objective hearing evaluation was investigated in the rabbit as an animal model. The contralateral stapedius reflex to acoustic and electrical stimulation was measured in anesthetized rabbits. For electrical stimulation, the middle ear was opened surgically and stimulation was applied by a monopolar electrode placed at or into the round window. Contraction of the middle ear muscle was monitored by digital sampling and averaging of the impedance changes in the contralateral ear. Acoustically evoked reflexes were recorded within expected limits despite anesthesia. The level of the electrical stimulus was raised until mass reflexes of the neck muscles were observed. A contralateral stapedius reflex to electrical stimulation could not be demonstrated. In our experiment, monopolar electrical stimulation at the round window could not elicit contralateral stapedius reflexes.

Acoustic Stimulation↗
PubMed2006

[Functional disturbances of the cervical spine in tinnitus].

BACKGROUND: A total of 189 patients with tinnitus, Meniere's disease, and sudden hearing loss underwent manual therapeutic examination at the Department of Physical Medicine and Rehabilitation in the setting of an interdisciplinary program for the management of patients of the tinnitus daycare center and inpatients of the ENT department of the Charité Medical School. METHOD: In all patients, global and segmental joint mobility of the cervical spine, cervicothoracic junction, first rib, and craniomandibular system was assessed using standardized documentation. Muscle extensibility and trigger points were determined for the sternocleidomastoid muscle, the descending part of the trapezius muscle, the levator muscle of the scapula, and the masseter muscle. RESULTS: Results of the statistical analysis show that patients with tinnitus have characteristic and specific patterns of abnormalities in the joints and paravertebral muscles. The dominant finding is an overall impairment of cervical spine mobility, to which various factors contribute. These include disturbed function of segmental joints of the head and the cervicothoracic junction as well as muscular imbalances of the shoulder and neck muscles. CONCLUSION: Our results corroborate the clinical significance of manual therapeutic findings as part of the diagnostic workup for tinnitus. They show that a uniform and standardized examination protocol is needed, and that appropriate physical therapeutic measures should be incorporated into the interdisciplinary therapeutic management of patients with tinnitus.

Adolescent↗
PubMed2001

Imaging of blood flow and hypoxia in head and neck cancer: initial evaluation with [(15)O]H(2)O and [(18)F]fluoroerythronitroimidazole PET.

UNLABELLED: Hypoxia is a characteristic feature of malignant tumors that should be evaluated before the start of therapy. (18)F-labeled fluoroerythronitroimidazole (FETNIM) is a possible candidate for imaging tumor hypoxia with PET. Quantitative analysis of [(18)F]FETNIM uptake in vivo is necessary before proceeding to assays predicting hypoxia. METHODS: Eight patients with untreated head and neck squamous cell carcinoma were enrolled in the study. All patients underwent dynamic PET imaging with [(18)F]FETNIM, coupled with measurements of blood flow with [(15)O]H(2)O and blood volume with [(15)O]CO. The metabolically active tumor volume was determined from [(18)F]FDG PET performed on a separate day. [(18)F]FETNIM uptake in the tumor was correlated with that in neck muscles and arterial plasma and compared with the findings of other PET studies. RESULTS: Blood flow in tumor was 5- to 30-fold greater than in muscle, in contrast to blood volume, which did not significantly differ in the 2 tissues. With [(18)F]FETNIM PET, muscle activity remained invariably less than plasma activity, whereas activity in whole tumors was always greater than that in muscle. In 4 instances, the maximum tumor uptake of [(18)F]FETNIM was 1.2-2.0 times higher than plasma activity in the late dynamic phase. A kinetic model developed for calculation of distribution volume of reversibly trapping tracers was successfully applied in the [(18)F]FETNIM studies. Tumor distribution volume correlated strongly with the standardized uptake value of [(18)F]FETNIM between 60 and 120 min and with blood flow but not with the standardized uptake value of [(18)F]FDG. The relationship between [(18)F]FETNIM uptake and the blood flow of the tumor was less obvious on a pixel-by-pixel level. CONCLUSION: Uptake of [(18)F]FETNIM in head and neck cancer is highly variable and seems to be governed by blood flow at least in the early phase of tissue accumulation. Maximum tumor-to-muscle tracer uptake ratios > 180 min were in the range of 1-4, comparing favorably with those reported previously for [(18)F]fluoromisonidazole. Assessment of the distribution volume of [(18)F]FETNIM after the initial blood-flow phase is feasible for subsequent evaluation of hypoxia-specific retention.

Aged↗
PubMed2005

Dynamics and directionality of the vestibulo-collic reflex (VCR) in mice.

The vestibulo-collic reflex (VCR) stabilizes the head in space by excitation of neck muscles that oppose head rotation. Recently, the mouse vestibulo-ocular reflex (VOR) has been characterized so that genetic manipulations of the vestibular system can be examined. We have characterized the dynamics and directionality of the VCR in mice restrained at the neck so that studies of vestibular system genetics may include comparisons to normal VCR in addition to VOR. Head rotations were measured in darkness with a three-dimensional search coil system during whole body rotations. The VCR in four C57BL/6 mice was present in pitch, roll, and yaw directions with an overall average gain of 0.28. Phase was accurately compensatory to oppose head rotation across a wide range of frequencies from 0.02 Hz to 2.0 Hz. Compensatory head rotations were greatest in the direction opposing the applied stimulus and weak or absent in other directions. Constant velocity rotations about horizontal axes elicited head velocity modulation and bias similar to that observed in the VOR. We conclude that the VCR of mice is similar to that in other mammals.

Animals↗
PubMedDate not supplied

MRI of cerebrum and cervical columna within two days after whiplash neck sprain injury.

The present study was undertaken to evaluate if MRI within 2 days of a motor vehicle accident could reveal pathology of importance for understanding long-term disability after whiplash neck-sprain injuries. As part of a prospective study cervical and cerebral MRI was performed on 40 neck sprain patients with whiplash injury after car accidents. The imaging was done within 2 days of the injury to make sure that any neck muscle bleeding, oedema or other soft tissue injuries could be detected. The MRI findings from the patients were both correlated to reported symptoms 6 months after the accident and compared to a control group of 20 volunteers. The MRI of both brain and neck revealed no significant differences between the patients and the control group. When the patients were grouped according to the main MRI findings at intake and compared according to the development of subjective symptoms reported by the patients, the only significant difference was more headaches at 6 months in the groups with disk pathology or spondylosis when compared to the group with no pathology. In conclusion, MRI within 2 days of the whiplash neck-sprain injury could not detect pathology connected to the injury nor predict symptom development and outcome.

Accidents, Traffic↗
PubMed1994

Botulinum toxin in the treatment of dystonic tics.

Botulinum toxin (BTX) injections provide effective treatment for a variety of disorders manifested by inappropriate muscle contractions, but its efficacy in the treatment of tics has not been previously studied. Ten male patients 13-53 years of age who were diagnosed with Tourette's syndrome manifested by disabling focal tics were included in this pilot study. Five patients had frequent blinking and blepharospasm, rendering them "blind," and five patients had severe and painful dystonic tics involving their neck muscles. All 10 patients experienced moderate to marked improvement in the intensity and frequency of tics after BTX injections into the involved muscles. Patients in whom premonitory urges preceded their tics noted marked lessening of these sensory symptoms. The benefit lasted 2-20 weeks after injections. There were no serious complications, except for transient ptosis in two and neck pain, stiffness, or weakness in three patients. BTX injections appear to be safe and effective treatment for patients with focal dystonic tics. The treatment ameliorates not only involuntary movements but also the premonitory sensory component associated with some tics.

Adolescent↗
PubMedDate not supplied

Changes in cholinergic and purinergic neurotransmission in the diabetic rabbit bladder.

BACKGROUND: Diabetes mellitus (DM)-associated alterations in bladder function have been attributed to changes in autonomic receptors and alterations in detrusor structure and function. The changes in cholinergic and purinergic neurotransmission in the DM rabbit bladder were evaluated. MATERIALS AND METHODS: DM was induced with alloxan in adult male New Zealand White rabbits. At 6 months, detrusor and bladder neck muscle strips were obtained and mounted in organ baths. Transmural electrical field stimulation (EFS: supramaximal voltage, 0.1 ms duration, 10 s trains) was performed in the presence of atropine (10(-6) M) or alpha, beta-methylene ATP (10(-6) M), and after adding tetrodotoxin10(-6) M. Purinergic, alpha, beta-methylene ATP-sensitive, and cholinergic, atropine-sensitive, components were calculated independently and compared with those from controls. RESULTS: Both normal and DM detrusor and bladder neck strips contracted in a frequency-dependent fashion in response to transmural EFS. A plot of EFS vs. detrusor contractility showed a decrease (ANOVA < 0.001) in the cholinergic nerve-mediated component, whereas the purinergic nerve-mediated component was increased (ANOVA < 0.001) in the DM detrusor compared to the control. The total EFS- and KCl-induced responses were unaltered in the DM group compared to the controls. There was no difference in purinergic, alpha, beta-methylene ATP-sensitive, and cholinergic, atropine-sensitive, components in strips from the bladder neck for both normal and DM rabbits. CONCLUSION: These results suggest that an enhancement of purinergic and a reduction of cholinergic neurotransmission occur in the detrusor muscle of the diabetic rabbit. These changes may contribute to the pathophysiology of diabetic cystopathy.

Animals↗
PubMed1982

[Computed tomography and ultrasound: comparison with intraoperative findings of large metastases in the neck (author's transl)].

The evaluation of soft tissue lesions in cases with extensive metastases, in the neck is of great importance. The therapeutic concept will depend upon the size distribution and infiltration of the metastases into the structures of the lateral neck. The limiting factors include the great vessels of the neck, the deep neck muscles, the base of the skull, the mediastinum and the proximal parts of trachea and oesophagus. The timing of therapy (operation, radiation and cytostatic therapy) can be planned according to these factors. Computed tomography and ultrasound provide the information about the soft tissues of the neck. Spread, size and site of infiltration can be fairly estimated as shown in 25 patients which have been operated on.

Adult↗
PubMed2005

Monitor height affects surgeons' stress level and performance on minimally invasive surgery tasks.

This study investigated the effect of monitor height on surgeons' workload and performance during simulated minimally invasive surgery (MIS). Fourteen volunteer subjects (7 experienced, 7 inexperienced) performed a cutting task in a training box at a standard MIS station with the video monitor positioned in random order at, below (-35 degrees), and above (+15 degrees) the subject's eye level. Task time and error, difficulty and discomfort, head orientation, trapezius and neck muscle activity, and skin conductance were recorded. The experienced subjects performed the task faster, with less error, and with less difficulty than did the inexperienced subjects. For the experienced subjects, error decreased when the monitor was lowered. Difficulty and discomfort increased at the high monitor position. As the monitor was lowered, the head pitched forward, and paraspinal cervical muscle activity increased. Variability in sternocleidomastoid activity increased both at the low and high monitor positions. The results show that monitor height affects both performance and workload. The monitor should be lowered to reduce error and task difficulty but not so low as to produce excessive neck flexion.

Adult↗
PubMed1993

The oculo-auricular phenomenon. Findings in normals and patients with brainstem lesions.

The oculo-auricular phenomenon consists of bilateral coactivation of external ear muscles during lateral gaze. The electromyogram of the transverse auricular muscle was recorded in 25 healthy volunteers and 1186 patients. In normal subjects bilateral coactivation was observed with lateral gaze (96%), convergence (61%), active and intended head rotation (100%) and passive head rotation (50%). Uni- and bilateral labyrinthine excitation (60 and 80%) and proprioceptive input from the neck muscles (38%) are also effective. In patients with brainstem disease abnormal transverse auricular muscle coactivation is characterized by absence of activity in one or both ear muscles during lateral gaze in either or both directions. The most frequent abnormality was absence of transverse auricular muscle activity homolateral to right or left gaze (type Ia pattern). It was related to homolateral impairment of the blink reflex R1-response (90%) and the caloric response (90%), and to contralateral masseter reflex abnormality (70%). Electrophysiological data, clinical signs and imaging findings indicate that the type Ia pattern is caused by homolateral pontine or contralateral midbrain lesions. It is suggested that the supranuclear organization of the oculo-auricular phenomenon is based on descending tracts crossing at a mid-pontine level.

Brain Diseases↗
PubMed2004

Hyperekplexia and stiff-man syndrome: abnormal brainstem reflexes suggest a physiological relationship.

BACKGROUND AND OBJECTIVES: Hyperekplexia and the stiff-man syndrome (SMS) are both conditions with exaggerated startle suggesting abnormal brainstem function. Investigation of brainstem reflexes may provide insight into disturbed reflex excitation and inhibition underlying these movement disorders. PATIENTS AND METHODS: Using four-channel EMG, we examined four trigeminal brainstem reflexes (monosynaptic masseter, masseter inhibitory, glabella, and orbicularis oculi blink reflexes) and their spread into pericranial muscles in five patients with familial hyperekplexia (FH), two with acquired hyperekplexia (AH), 10 with SMS, and 15 healthy control subjects. RESULTS: Both FH/AH and SMS patients had abnormal propagation of brainstem reflexes into pericranial muscles. All patients with hyperekplexia showed an abnormal short-latency (15-20 ms) reflex in the trapezius muscle with a characteristic clinical appearance ("head retraction jerk") evoked by tactile or electrical stimulation of the trigeminal nerve, but normal monosynaptic masseter reflexes. Inhibitory brainstem reflexes were attenuated in some FH/AH patients. Four of 10 patients with SMS had similar short-latency reflexes in the neck muscles and frequently showed widespread enhancement of other excitatory reflexes, reflex spasms, and attenuation of inhibitory brainstem reflexes. CONCLUSION: Reflex excitation is exaggerated and inhibition is attenuated in both stiff-man syndrome and familial or acquired hyperekplexia, indicating a physiological relationship. Reflex transmission in the brainstem appears biased towards excitation which may imply dysfunction of inhibitory glycinergic or GABAergic interneurons, or both.

Adolescent↗
PubMed2006

[Experimental research of discordant tracheal xenotransplantation].

OBJECTIVE: To investigate the immunological rejection mechanism of tracheal xenotransplantation and xenografts as potential sources of trachea. METHODS: On SD rat model, a xenotransplanted tracheal from the guinea pig was established by wrapping it in the cervical muscles in situ. It was divided into cryopreserved group and uncryopreserved group. Under the examinations with histochemistry, immunofluorescence (IFL) and flow cytometry (FCM) techniques, the pathomorphological characteristics of the tracheal xenografts and the immunological rejection mechanism were evaluated. RESULTS: The tracheal allotransplantation with cryopreserved grafts wrapped by neck muscles was survived for a longer period. Histological examination revealed normal appearance of the allografts. The tracheal grafts patency was above 80%. However, cryopreserved tracheal xenografts of the guinea pig-to-rat maintained vitality for 14 days in maximum and 13.2 days on average, while the fresh tracheal xenografts only for 9 days in maximum, and 8 days on average. Acute rejection occurred in the tracheal xenotransplantation. A marked mononuclear-macrophage cellular infiltration mixed with eosinophils and lymphocyte was seen in the xenografts. Antibody (IgM, IgG) and complement (C3) deposition were also obviously detected by IFL in the xenografts. CD4 T+ cells and CD8+ T cells increased significantly in the vascular circulation. In all of the xenografts, complete loss of tracheal epithelium was associated with cartilage necrosis. The grafts patency was below 50%. This performance deteriorated with extended time periods. The fresh xenografts performed significantly worse than the cryopreserved xenografts. CONCLUSIONS: Acute rejection, caused by humoral immune reaction mainly integrated with cellular immunity, is the most notable characteristics in the guinea pig-to-rat tracheal xenotransplantation in situ. Cryopreservation can potentially reduce the antigenicity. The low antigenicity may inhibit the immunologic reaction relatively, so that prolonged survival of discordant cryopreserved tracheal xenografts could be achieved.

Animals↗
PubMed1995

[A Japanese family with paramyotonia congenita which has a mutation in the muscle sodium channel gene].

We report here a Japanese family with paramyotonia congenita. The proband was a 42-year-old woman (case 1), who noticed muscle stiffness and weakness in the cold since the age of 7 years. These symptoms were alleviated by warming. Her eldest son (case 2) also experienced similar symptoms, while her younger son and daughter were healthy. Neurological examination in case 1 revealed mild weakness in facial and neck muscles. Cold-induced muscle stiffness and weakness were present. Electromyography showed myotonic discharges, intensified by cooling or repetitive exercise. The amplitude of the compound muscle action potentials was also reduced by the repetitive exercise and cooling. Serum chemistry including potassium and CK was normal. Molecular analysis of SCN4A (exon22-24) by SSCP and nucleotide sequencing revealed a C-to-T transition at nucleotide 3,938, causing a substitution of 1313methionine of threonine in case 1. This mutation was confirmed by PCR-RFLP with a mismatched primer; the proband (case 1) and her eldest son (case 2) had a heterozygous mutation, while the other family members did not. This is the first report that a mutation in SCN4A was identified in a Japanese family with paramyotonia congenita.

Adult↗
PubMed1998

Trichinella spiralis, T. britovi, and T. nativa: infectivity, larval distribution in muscle, and antibody response after experimental infection of pigs.

The infectivity of Trichinella spiralis, T. nativa, and T. britovi was experimentally compared in pigs. Blood sampling was performed weekly, and muscle juices were obtained at slaughter 10 weeks after inoculation. Muscle larvae were found in all of four pigs inoculated with T. spiralis [mean 190 larvae per gram (lpg)] and in three of four pigs inoculated with T. britovi (mean 7 lpg). No larvae were found in pigs inoculated with T. nativa. For T. spiralis and T. britovi, the neck muscle (m. splenius) appears to be a predilection site in addition to the tongue, the diaphragm, and the jaw. High antibody responses were found in all experimental groups, independent of the antigen used, and even in pigs in which no muscle larvae were recovered. The strong and consistent antibody response found with meat juice indicates the usefulness of this material where a blood sample is not obtainable, e.g. meat samples from wild animals. Immunoblotting (Western blots) on slaughter sera revealed no species specificity when comparing homologous versus heterologous staining.

Animals↗
PubMed2001

Role of NK2 receptors in gastric barosensitivity and in experimental ileus in rats.

This study was performed to evaluate the role of tachykinin NK2 receptors in gastric barosensitivity and in postsurgical intestinal atony, using a selective NK2 antagonist (MEN 11420). Gastric distensions were performed in rats equipped with a gastric balloon and electrodes implanted in the neck muscles. Ileus was produced by laparotomy and caecum palpation in rats previously prepared with electrodes implanted on the proximal jejunum. Fifteen minutes before gastric distension or laparotomy, the animals received MEN 11420 (10, 100 or 200 microg kg-1 intravenously) or saline. The first distending pressure to increase the integrated neck electromyogram > 100% was considered the pain threshold. MEN 11420 (100 microg kg-1) increased significantly pain threshold (20.5 +/- 1.2 vs. 17.0 +/- 0.8 mm Hg) but did not modify gastric volumes at the three doses tested. Abdominal surgery was followed by a total inhibition of jejunal spiking activity lasting 80.4 +/- 18.7 min. MEN 11420 (10 and 100 microg kg-1) shortened the duration of motor inhibition by 36 and 39%, and induced a premature recovery of the phase III of migrating myoelectric complex at the lowest dose tested (130 +/- 32 vs. 192 +/- 28 min). We conclude that NK2 receptors, probably located on afferent fibres, are involved in gastric barosensitivity and in postsurgical intestinal atony.

Adrenergic alpha-Antagonists↗
PubMed1996

Anticipatory EMG responses of pericranial muscles in relation to heart rate during a warned simple reaction time task.

Obrist's cardiac-somatic coupling hypothesis predicts a widespread inhibition of heart rate and task-irrelevant muscle activity during expectancy situations. This hypothesis was tested by measuring heart rate and pericranial electromyographic (EMG) activity during a warned simple reaction time task with visual or auditory reaction signals and hand or foot responses. In each of three groups of 24 participants, EMG activity of three different facial, masticatory, or neck muscles was recorded. During the warning interval preceding the presentation of the reaction signal, masticatory and lower facial muscles predominantly showed a gradual inhibition in activity concomitant with heart rate deceleration. In contrast, two upper facial muscles showed increasing activity. Pericranial EMG responses were little affected by reaction signal modality and were independent of responding limb. Greater heart rate deceleration was associated with greater inhibition and weaker facilitation of EMG responses. The results suggest a functional role of inhibitory EMG responses in increasing the perceptual sensitivity to expected signals.

Adult↗