Intraoperative EMG recording in stimulation of the glenohumeral joint capsule

In an experimental study we investigated the EMG response in 10 patients after intraarticular stimulation of the joint capsule. Intraoperative stimulation was achieved by arthroscopic placement of the stimulation catheter at the anterior joint capsule. The muscle response was documented by mono- or bipolar electrodes. We found reproducible EMG muscle responses in both superficial and deep muscle layers. The response time was between 100 and 516 ms. The shortest muscle response was found at the anterior part of the deltoid muscle and the longest at the supraspinatus muscle and the lateral part of the deltoid muscle.     

The effect of radiofrequency energy on the length and temperature properties of the glenohumeral joint capsule

Two isozymes of mammalian methionine adenosyltransferase, MAT I and MAT III, are expressed solely in adult liver. They are, respectively, tetramers and dimers of a single subunit encoded by the gene MAT1A. A third isozyme, MAT II, contains a catalytic subunit encoded by a separate gene, MAT2A, and is expressed in a variety of tissues, including (to a slight extent) adult liver. Based on a recent finding that 2 children with isolated hypermethioninemia and brain demyelination were homozygous for MAT1A mutations predicted to produce severely truncated proteins, and devoid of activity when expressed, it was concluded that complete lack of MAT I/III activity may be associated with neurological symptoms and demyelination. We now report that a 43-year-old man with persistent isolated hypermethioninemia, previously demonstrated to have deficient MAT activity in his liver, has normal brain myelination on MRI and normal neurological function, despite being homozygous for a 539 TG insertion in exon V of MAT1A, so that the gene is predicted to encode a protein of only 184 rather than the normal 395 amino acids. This patient's exon V mutation was demonstrated by SSCP analysis and verified by sequencing. Both parents are heterozygous for the same insertion. This suggests that MAT1A mutations producing severely truncated proteins do not necessarily produce brain demyelination. This finding has relevance to a previously reported 4-year-old girl who was also homozygous for the 539insTG mutation. Finally, our patient's 7% residual hepatic MAT activity, measured at 1 mM methionine, may reflect the hepatic activity of the more ubiquitous enzyme form, MAT II.     

MR arthrography of the glenohumeral joint

The review contains the present-day data on new neurophysiological and neurochemical mechanisms of learning and memory processes disturbances induced by such extreme factors as microwaves, hypoxia [correction of hyghproxia], motion sickness, electro-convulsive shock, etc. The main attention is concentrated on the role of some nootropic drugs in preventing the memory-impairing effect of all these extreme factors. The current concept of the mechanisms action of the nootropics in these extreme conditions is discussed.     

Mechanisms of glenohumeral joint stability

The biomechanics of glenohumeral stability involve several static and dynamic mechanisms to achieve the intricate balance between shoulder mobility and stability. In conjunction with recent in vitro studies, two important stabilizing mechanisms, concavity compression and scapulohumeral balance, were described. Concavity compression refers to the stability obtained by compressing the humeral head into the concave glenoid fossa. Increasing the magnitude of the compressive load, as provided by dynamic muscle contraction, and the depth of the glenoid concavity, which varies from the asymmetric geometry, enhance concavity compression stabilization. The related scapulohumeral balance refers to the dynamic positioning of the glenohumeral joint so that the joint reaction force is balanced within the glenoid fossa. The greater the arc provided by the glenoid, the larger the range of joint force angles acting through the humeral head that may be stabilized. The presence of an intact glenoid labrum is important to both mechanisms. Concavity compression and scapulohumeral balance may be of particular importance to glenohumeral joint stability in the midrange of motion where the capsuloligamentous constraints are lax. Clinical correlation of these mechanisms contributes to the understanding of glenohumeral instability.     

Electrical stimulation of the lingual musculature in obstructive sleep apnea

The influence of lingual muscle activity on airflow dynamics in the upper airway was examined in nine patients with obstructive sleep apnea. Muscles that retract the tongue (hyoglossus and styloglossus) and protrude the tongue (genioglossus) were selectively stimulated electrically during sleep with fine wire electrodes placed intramuscularly transorally. We confirmed that stimulation with 50 Hz and 40-microseconds pulse duration did not elicit changes in electroencephalographic patterns or heart rate or alter airflow after the stimulation burst had ceased. The highest stimulus intensity that did not arouse patients from sleep was then utilized to examine the effect of lingual muscle recruitment on airflow dynamics during steady-state periods of inspiratory airflow limitation. When applying a stimulus burst during single inspirations, maximal inspiratory airflow decreased by 239 +/- 177 ml/s (P < 0.05) during retractor stimulation, whereas maximal inspiratory airflow increased by 217 +/- 93 ml/s during protrusor stimulation (P < 0.001) compared with breaths immediately before and after the stimulated breath. When consecutive inspirations were stimulated repeatedly, protrusor stimulation decreased the frequency of obstructive breathing episodes in four patients breathing at 3.9 +/- 3.4 (SD) cmH2O nasal pressure. The findings suggest that stimulation of the lingual muscles can increase or decrease airflow depending on the specific muscles stimulated without arousing patients from sleep.     

The medial capsule of the human temporomandibular joint

PURPOSE: Attachments of the medial capsule of the temporomandibular joint (TMJ) to structures other than the medial fossa wall are thought to exist and to have functional significance. This study evaluated these relationships. MATERIALS AND METHODS: The anatomic relationships between the medial capsule and other medial structures, the sphenomandibular ligament, discomalleolar ligament, and auriculotemporal nerve, were examined in 14 cadaver heads. RESULTS: The results showed that the sphenomandibular ligament attaches separately from the medial capsule of the TMJ and therefore has no functional significance to the biomechanics of the joint. The discomalleolar ligament was found to be a continuation of the retrodiscal tissues and minimally associated with the medial capsule. The auriculotemporal nerve was not found to be in a relationship with the medial aspect of the condyle to the extent that mechanical irritation is possible during TMJ movement or disc displacement.     

Responses of mechanoreceptor neurons in the cat knee joint capsule before and after anterior cruciate ligament transection

It is known that afferent neurons play a protective role in knees made unstable by transection of the anterior cruciate ligament. However, it is not known whether cutting the anterior cruciate ligament has an effect on the response of the sensory neurons that innervate the joint. In this study, the responsiveness (activation threshold and position sensitivity) of single, mechanically sensitive afferent neurons from the cat knee was evaluated by a series of extension, internal, and external rotations. The anterior cruciate ligament then was cut and the same procedure was repeated. Transection of the ligament increased joint laxity for all types of rotation. The responsiveness of the neurons was not changed significantly by cutting the ligament (p > 0.05). Therefore, capsule afferents continue to behave normally in joints in which the anterior cruciate ligament has been transected.     

Relaxation measured by EMG as a function of vibrotactile stimulation

Key pecking of two pigeons was maintained under a multiple schedule of food presentation. In the presence of one keylight stimulus responding produced food according to a fixed-interval 5-min schedule. Additionally, during this component, each 50th response produced electric shock. When a different keylight stimulus was present, key pecking resulted in food delivery under a variable-interval 3-min schedule. Responding was suppressed by shock presentation (punishment) but was still positively accelerated throughout each fixed-interval cycle; steady response rates occurred during the alternate component when only the variable-interval schedule was in effect. Overall rates of punished responding were largely unchanged with d-amphetamine (0.1-3.0 mg/kg); unpunished responding was generally either increased slightly or was decreased. Pentobarbital and chlordiazepoxide (1.0-17.0 mg/kg) administered alone increased both punished and unpunished responding at most doses. Combinations of d-amphetamine with either pentobarbital or chlordiazepoxide produced increases in punished responding that exceeded those obtained with either of these drugs alone. The combined effects of d-amphetamine and either pentobarbital or chlordiazepoxide on unpunished responding depended on the individual dose combinations. Combinations of d-amphetamine with pentobarbital or chlordiazepoxide produced effects on both punished and unpunished responding that differed substantially from those obtained when any of these drugs were administered separately.     

Intraoperative monitoring of the function of the peroneal nerve in knee joint operations

Operations on the knee are known to be associated with postoperative neurological complications. There is no consensus opinion on the causes of these complications. The aim of the present study was to develop a method for the intraoperative monitoring of the function of the common peroneal nerve. This was done as to identify intraoperative factors that might be responsible for reversible and irreversible neurological deficits. Computer-aided neuromonitoring is based on online digitizing of the surface EMG of the anterior tibial muscle. An algorithm continuously modifies the amplitude to determine the motor threshold. The method described has been used in 18 patients undergoing high tibial osteotomy. In 10 of the 18 patients, the nerve is rendered completely non-excitable after an average tourniquet application time of 59 min. This non-excitability was reversed on release of the tourniquet. In the remaining 8 patients, excitability was maintained throughout the ischaemic period, which did not exceed 60 minutes in any of the cases. Our method enables accurate quantification of the neural function throughout the entire operation, and convincingly documents the influence of ischaemia on peripheral nerve block.     

Contribution of the anterolateral joint capsule to the mechanical stability of the ankle

Published reports describe the clinical efficacy of modified Brostrom anatomic repairs, surgical procedures that involve repair and fortification of the lateral capsuloligamentous complex of the ankle for patients suffering from chronic lateral instability of this joint. A cadaveric serial sectioning study of the anterior talofibular ligament, the calcaneofibular ligament, and the remainder of the anterolateral joint capsule was completed to quantitate the contribution of the superior portion of the anterolateral joint capsule, independent of the other two structures, to the overall mechanical stability of the lateral ankle. Using 20 fresh frozen specimens, talar tilt and anterior drawer stress radiographs were taken before and after sectioning these anatomic structures in an order established by one of two protocols. Sectioning of the superior anterolateral joint capsule caused 17% to 18% of the total displacement in a Grade II sprain simulation and 29% to 33% of the total displacement in a Grade III sprain simulation. This work suggests that disruption of the segment of ankle joint capsule superior to the anterior talofibular ligament creates approximately 30% of the overall laxity encountered in a Grade III inversion sprain, substantiating the principle of restoring the integrity of the entire anterolateral joint capsule when operating on a chronically unstable ankle.     

Distribution of normal and abnormal fluid collections in the glenohumeral joint: implications for MR arthrography

OBJECTIVE: This study determined levels of cathepsin D activity in tissue components of normal human ovary to establish a basis for comparison with human ovarian adenocarcinomas. METHODS: Cathepsin D activity per mg tissue, per microgram protein, and per microgram DNA was determined in human ovarian tissues (cortex, follicle, corpus luteum, corpus albicans) from patients of various ages and during the menstrual cycle. Levels of cathepsin D activity were also determined in ovarian adenocarcinomas and other pathologic tissues. RESULTS: Cathepsin D levels (per mg tissue) were significantly greater (P < .001) in ovarian follicle and corpus luteum compared with cortex. Although there was not a clear correlation between enzyme activity in the cortex and day of the menstrual cycle or patient age, levels of enzyme activity appeared to decrease with each parameter. Cathepsin D levels per mg tissue in ovarian adenocarcinoma were 40% higher than in postmenopausal ovarian cortex, but the difference was not statistically significant. CONCLUSION: The diversity of cathepsin D levels in normal ovarian tissue compartments indicates that specific tissues must be used in comparisons with ovarian tumors.     

Measuring the anterior capsule opening after cataract surgery to assess capsule shrinkage

PURPOSE: To measure anterior capsule opening (ACO) size after acrylic intraocular lens (IOL) implantation and study the natural course of ACO reduction. SETTING: Kimura Eye and Internal Medicine Hospital, Hiroshima, Japan. METHODS: This study comprised 32 patients (38 eyes) having continuous curvilinear capsulorhexis, phacoemulsification, acrylic IOL implantation, and a self-sealing incision performed by 1 surgeon. A retroillumination photograph of the ACO was obtained with the Anterior Eye Segment Analysis System and converted to a computer image. The images were used to measure ACO size postoperatively and calculate the reduction ratio. Follow-up was 6 months. RESULTS: The postoperative reduction ratio in ACO size was 2.14% at 1 week, 3.83% at 1 month, 4.29% at 3 months, and 5.03% at 6 months. In a few cases, the reduction was progressively severe throughout the follow-up. CONCLUSIONS: The anterior capsule opening shrank rapidly during the first month after acrylic IOL implantation, followed by a slower progressive reduction in the subsequent 6 months. When severe, progressive shrinkage occurs, an anterior neodymium:YAG laser capsulotomy should be performed within 2 months postoperatively.     

Intraoperative extra strong electrical stimulation in the treatment of peripheral nerve injury

OBJECTIVE: To explore the Yinji Capsule (YJC) in improving the left ventricular systolic function of angina pectoris patients with Blood Stasis Syndrome. METHODS: The systolic function of left ventricle (LV) in cardiac cycle of 28 angina pectoris patients with Blood Stasis Syndrome was examined with three-dimensional echocardiograph (3-DE) before and after treatment with YJC. RESULTS: The total symptomatic effective rate was 85.7%. The changes of LV systolic function were those: left ventricle ejection fraction (LVEF) increased from 45.0 +/- 4.9% to 48.2 +/- 3.5% (P < 0.05); EF on early stage and late stage increased from 22.6 +/- 2.1%, 8.3 +/- 1.2% to 28.1 +/- 3.0% and 10.3 +/- 0.9% respectively (P < 0.01, P < 0.05), myocardial region with segment systole (SS) < 5% decreased significantly (P < 0.01). CONCLUSION: YJC could improve LV systolic function on early stage and late stage in cardiac cycles, and mainly improve the systolic function of the region with low SS of LV.     

Contrast media in MR arthrography of the glenohumeral joint: intra-articular gadopentetate vs saline: preliminary results

Progress has been made in the identification of experimental and analytical procedures that allow for a more reliable determination of equilibrium and kinetic constants. Possible origins of the frequently observed deviations of the measured binding progress from that expected for chemical binding of pseudo-first order, and appropriate experimental controls have been proposed. Improved analytical approaches include the application of global analysis and analytical corrections for the influence of mass transport.     

Intraoperative monitoring of the motor pathway using transtracheal stimulation of the cervical spine in dogs

Although SEP monitoring of the spinal cord has been a well established method recently, not an ultimate, perfectly developed technique for monitoring of the motor system is known so far, particularly, because of the disturbing effect of narcotic drugs and relaxants on the motor evoked potentials. In this study the upper part of the spinal cord was stimulated in 14 anesthetized and relaxed dogs with a cathode attached to the intratracheal tube and an anode fixed to the cervical spinous processes. Single and serial stimuli were applied. Recordings were obtained from the exposed right femoral nerve and quadriceps muscle. Averaging was necessary when using serial stimulations. Responses were consequent and reproducible during regular anesthesia. The origin of the different responses in the spinal cord is discussed. The method seems to be appropriate for intraoperative monitoring of the thoracolumbar spine.     

Closed reduction and tendon transfer for treatment of dislocation of the glenohumeral joint secondary to brachial plexus birth palsy

Dislocation of the glenohumeral joint developed, in the first few years of life, in eight children who had brachial plexus birth palsy. The palsy involved the fifth and sixth cervical nerve roots in six children and the fifth, sixth, and seventh cervical nerve roots in two. All of the children had a release of the insertions of the pectoralis major, latissimus dorsi, and teres major followed by a closed reduction of the glenohumeral joint. The latissimus dorsi and the teres major were then transferred to the rotator cuff. All of the children had a well located glenohumeral joint with at least 25 degrees (mean, 51 degrees) of external rotation and at least 135 degrees (mean, 164 degrees) of abduction at the latest follow-up examination, at least two years postoperatively. Strength in abduction increased at least one grade, and strength in external rotation increased at least two grades. The improved motion and strength allowed the children to place the hands more effectively above the head and helped them to perform activities of daily living easily.     

Specification of the hypaxial musculature

During development of the amniote embryo, the dorsolateral territory of the somite is destined to give rise to the hypaxial skeletal musculature. To study the mechanisms that lead to the formation of this musculature, we cloned the chick Lbx1 gene that is specific to prospective hypaxial myoblasts at occipital, cervical and limb levels. Using this gene as a marker, we characterised the anatomical structures that produce the signals necessary for the specification of the hypaxial musculature by ablating them or transplanting them to ectopic locations in the chick embryo. In addition, we inserted BMP4 soaked beads medial to the somite. Our data suggest that lateralising signals from intermediate and lateral mesoderm have to synergise with dorsalising signals from the surface ectoderm to induce the formation of the hypaxial musculature. However, the lateralising function of the lateral mesoderm can only in part be mimicked by BMP4.     

Facial EMG as an index of affective response to nicotine.

Negative affect reduction has been postulated to be a key feature of cigarette smoking. In the present study, facial electromyography (EMG), heart rate (HR), and skin conductance response (SCR) were used to evaluate the affective significance of acute nicotine administration and overnight withdrawal. Smokers (N = 115) attended four 90-min laboratory assessment sessions scheduled approximately 3 days apart. The sessions provided a complete crossing of 2 prelaboratory deprivation conditions (12-hr deprived vs. nondeprived) with 2 drug conditions (nicotine vs. placebo nasal spray). During each session, smokers viewed affective slides while facial EMG, HR, and SCR were recorded. Results indicated that for women, nicotine nasal spray resulted in lower corrugator EMG activity during both smoking-deprived and nondeprived sessions, compared with placebo. However, nondeprived women also showed an increase in zygomaticus EMG when given nicotine compared with placebo spray, whereas smoking-deprived women demonstrated a decrease in the zygomaticus response to nicotine compared with placebo. With men, nicotine also appeared to lower corrugator during deprivation, but not nondeprivation, compared with placebo spray, though the contrast only approached significance. With zygomaticus EMG, nicotine spray decreased men's zygomaticus responding during nondeprivation but not during deprivation, compared with placebo spray. The HR results reflected the stimulatory properties of the drug rather than nicotine's affective properties, whereas SCR was unresponsive to our experimental manipulations. The corrugator EMG results support negative reinforcement models of smoking that postulate that acute nicotine use reduces withdrawal-driven negative affect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)