Simplified preformed chelate protein radiolabeling with technetium-99m mercaptoacetamidoadipoylglycylglycine (N3S-adipate)

The precentral P22/N30 cortical component of the median nerve somatosensory evoked potentials (SEPs) was recorded in 16 patients (11 women and five men) suffering from cervical dystonia before and after botulinum toxin therapy. Cervical dystonia was diagnosed as idiopathic in all patients: 13 patients suffered from right-sided torticollis, and three suffered from left-sided torticollis. The amplitude of the P22/N30 component and the side-to-side ratio of amplitude values were measured. Normal values were obtained by acquiring measurements in two groups of healthy volunteers (n1 = 20 and n2 = 20). The recordings in the first control group were done with the patient's head in a normal position, whereas, in the second control group, the patient kept the head intentionally rotated 60 degrees to the right. Patients were treated with local injections of botulinum toxin A (BTX-A). The mean duration of treatment was 8.3 months, and the mean total amount of BTX injected was 295 U. The P22/N30 precentral component was repeatedly recorded in patients after head posture had been corrected to the normal plane by BTX-A treatment. The recordings showed that the amplitude of the P22/N30 precentral component recorded contralaterally to the direction of head deviation was significantly higher in patients before treatment than after treatment. Contralateral pretreatment amplitudes were also significantly higher (p < 0.01 and p < 0.05, respectively) than amplitudes in both groups of healthy volunteers. The mean side-to-side ratio of precentral P22/N30 component amplitudes was significantly higher in patients before treatment compared with after treatment and also compared with both control groups. These changes in dystonic patients probably reflect the direction of head rotation, the muscle pattern of torticollis, and the change in force of dystonic contraction after the treatment. The changes presumably could be the result of higher excitability of the precentral cortex contralateral to head rotation in patients with cervical dystonia and its change after successful BTX-A treatment.     

Neurophysiological investigations in patients with head tremor

We studied 30 patients whose primary complaint was head tremor in an attempt to characterize neurophysiological aspects of their abnormal movement. Based on family medical history and physical examination, 23 patients had definite or probable essential tremor (essential head tremor, EHT). The remaining seven had mild dystonic signs accompanying their head tremor (head tremor plus dystonic signs, HT + DS). We recorded head movement and the electromyographic (EMG) activity of the sternomastoid and splenius capitis muscles, determined the spontaneous blinking rate, and measured the excitability recovery curve of the blink reflex and of the masseteric inhibitory reflex. All patients had tremor bursts at a frequency ranging between 3 and 9 Hz in at least one of the muscles examined. The predominant pattern seen when patients were sitting relaxed and facing forward was that of synchronized EMG bursts in both splenius capitis muscles. Maintenance of extreme head postures demonstrated two types of additional abnormalities: type 1 (enhancement of tremor), which was observed in 11 patients (47.8%) with EHT and in two (28.5%) with HT + DS; and type 2 (activation of neck muscles not required for maintenance of the posture), which was observed in two patients (8.7%) with EHT and in five (71.5%) with HT + DS (chi 2 = 26.4; p < 0.001). Mean blinking rate per minute was 24.9 +/- 14.6 in patients with EHT and 42.3 +/- 10.5 in patients with HT + DS (paired t test, p = 0.001). The blink reflex and masseteric inhibitory reflex excitability recovery curves showed an abnormal interneuronal excitability enhancement in seven (30.4%) of the 23 patients with EHT and in two (28.5%) of the seven with HT + DS (chi 2 = 3.1; p > 0.05). Abnormal patterns of EMG activity of the neck muscles correlated well with the presence of mild dystonic signs. However, the analysis of brainstem interneuronal excitability did not enable recognition of those patients with head tremor who could potentially develop cervical dystonia. The enhancement of brainstem interneuronal excitability found in approximately 30% of patients with head tremor could be related to plastic changes triggered by increased activity of the cranial muscles.     

Heterogeneity of motilin receptors in the gastrointestinal tract of the rabbit

Motilin, a 22-amino acid peptide synthesized in endocrine cells of intestinal mucosa, stimulates GI smooth muscle contractility. To elucidate the mode of action of motilin, we attempted to determine whether motilin receptors are localized on nerve cells or on smooth muscle cells of the GI tract. Mucosa-free tissues from rabbit antrum and duodenum were homogenized separately with a Polytron prior to differential centrifugation to obtain synaptosome or plasma membrane-enriched fractions, as determined by the distribution of [3H]saxitoxin (SAX) binding (neural membranes) and 5' nucleotidase (5'N) activity (smooth muscle plasma membranes). Motilin binding was evaluated by the displacement of [125I]motilin by motilin (1-22) on the various membrane fractions. In the antrum, motilin binding was highly correlated with SAX binding (r = 0.81, p < 0.0005), and also significantly with 5'N activity (r = 0.54, p < 0.05). In the duodenum, motilin binding correlated significantly with 5'N activity (r = 0.67, p < 0.005), but not with SAX binding (r = -0.11, NS). Receptor affinity, for the motilin antagonist MOT(1-12)[CH2NH]10-11, for motilin(1-22), and for the motilin agonist erythromycin lactobionate was significantly (p < 0.001, p < 0.001, and p < 0.05, respectively) higher in SAX-enriched fractions from the antrum than in 5'N-enriched fractions from the duodenum. Therefore, in the rabbit: 1) motilin receptors appear to be predominantly located on nerve tissues in the antrum and restricted to smooth muscle cells in the duodenum, and 2) antral receptors and duodenal receptors displayed different pharmacological characteristics, probably corresponding to two specific and heterogeneous motilin receptor subtypes.     

长时间颈部前屈对颈部肌肉疲劳的影响

长期颈部前屈对颈椎造成严重影响。为定量评估长时间低头对颈椎疲劳造成的影响，选取20名健康受试者，保持低头角度40°～60°持续3 h。选择胸锁乳突肌，颈部夹肌和肩部斜方肌测量其表面肌电信号。经滤波、整流、振幅标准化等处理后，对每60 s的肌电值进行积分和求其平均功率频率。研究发现，积分肌电值的波动变化具有规律性，首次增大后的减小表征肌肉进入疲劳状态；不同肌肉的平均功率频率(mean power frequency，MPF)值具有明显差异，决定着该肌肉疲劳耐受性的持续时间，且在整个颈部前屈过程中MPF并非简单的线性关系。提出用MPF的导数来提取疲劳特征，用窗口化的MPF负数累积判定肌肉疲劳。结果表明，MPF负数累积能很好地判断肌肉疲劳，胸锁乳突肌在20 min内出现最终疲劳，而颈部夹肌和肩部斜方肌在20 min左右出现了短暂性疲劳，随后在75～100 min时又出现了最终疲劳。因此建议持续颈部前屈时长不超过20 min。      

Influence of joint interactional effects on the coordination of planar two-joint arm movements

We have examined EMG-movement relations in two-joint planar arm movements to determine the influence of interactional torques on movement coordination. Explicitly defined combinations of elbow movements (ranging from 20 to 70 degrees) and wrist movements (ranging from 20 to 40 degrees) were performed during a visual, step-tracking task in which subjects were specifically required to attend to the initial and final angles at each joint. In all conditions the wrist and elbow rotated in the same direction, that is, flexion-flexion or extension-extension. Elbow movement kinematics were only slightly influenced by motion about the wrist. In contrast, the trajectory of the wrist movement was significantly influenced by uncompensated reaction torques resulting from movement about the elbow joint. At any given wrist amplitude, wrist movement duration increased and peak velocity decreased as elbow amplitude increased. In addition, as elbow amplitude increased, wrist movement onset was progressively delayed relative to this elbow movement. Surprisingly, the changes between joint movement onsets were not accompanied by corresponding changes between agonist EMG onsets at the elbow and wrist joints. The mean difference in onset times between elbow and wrist agonists (22-30 ms) remained unchanged across conditions. In addition, a basic pattern of muscle activation that scaled with movement amplitude was observed at each joint. Phasic agonist activity at the wrist and elbow joints remained remarkably similar across conditions and thus the changes in joint movement onset could not be attributed to changes in the motor commands.(ABSTRACT TRUNCATED AT 250 WORDS)     

Electrophysiologic evaluation of denervated muscles in incomplete paraplegia using macro electromyography

OBJECTIVE: To evaluate denervated muscles in persons with incomplete paraplegia due to thoracolumbar spinal injury (TLSI) using macro electromyography in determining indications for functional electrical stimulation (FES). DESIGN: A randomized clinical trial and a criterion standard. SETTING: A department of orthopedic surgery in a university hospital. PATIENTS AND OTHER PARTICIPANTS: Eighteen patients with incomplete paraplegia, including 11 with TSLI, and 50 healthy adults. INTERVENTION: Area and amplitude of macro motor unit potential (macro MUP) were measured at the tibialis anterior, the vastus lateralis, and the vastus medialis. The normal limits of macro MUP parameters were defined based on values from healthy subjects. Abnormal denervated muscles were detected by macro EMG and conventional EMG in paralytic patients. The correlation between macro MUP parameter values and muscle forces of the tibialis anterior and quadriceps femoris induced by electrical stimulation was analyzed. MAIN OUTCOME MEASURES: The number of abnormal muscles, parameter values, and muscle force induced by electrical stimulation. RESULTS: Abnormal muscles were found only in the TLSI patients and 13 abnormal muscles were detected by macro EMG only. The abnormal muscles defined by macro EMG showed insufficient contraction induced by electrical stimulation. The increase of parameter value negatively correlated with the muscle force (tibialis anterior area r=-.797, amplitude r=-.866; quadriceps area r=-.866, amplitude r=-.893; p < .001). CONCLUSIONS: These results suggest that macro EMG is useful in detecting denervated muscles, in determining indications for FES, and in predicting FES effects before implantation of electrodes.     

The role of the lateral pterygoid muscles in TMJ disorders during static conditions

Intramuscular EMG of the lateral pterygoid muscles (LPM), surface EMG of the temporalis and masseter muscles and force measurements of the temporomandibular joint (TMJ) were synchronously used to investigate the biomechanical role of the two heads of the LPM in relation to internal derangement (ID) of the TMJ. EMG and kinetic analysis of five static conditions (resting, protraction, opening, molar and incisor clenching) and three maximum isometric masticatory forces (opening, molar and incisor clenching) were done to compare forces and muscular activity between TMJ ID and control subjects. The analysis of variance results of the integrated linear envelope (LE) EMG showed no significant differences between the two groups for the masseter and temporalis muscles. Therefore, there is no apparent reason to believe that these muscles are hyperactive in TMJ ID. The integrated LE EMG of the SLP was significantly lower in the TMJ group during molar clenching (104 microV + 60.0 over 159 microV + 68.8 for a p = .020). The superior head of the lateral pterygoid muscle (SLP) seemed to have lost its diskal stabilizing function. The integrated LE EMG signals of the ILP were significantly higher in the TMJ ID group during rest, resisted protraction and incisor clenching (p = .029, p = .046, p = .031 respectively). The ILP muscle has probably adapted to control the inner joint instability while continuing its own actions. The ILP muscle seemed to have lost its functional specificity. The results of the isometric forces showed that TMJ ID subjects exhibited significantly lower molar bite forces (297.1N over 419N, p = .042) confirming that they have less muscle strength and tissue tolerance than subjects with healthy masticatory muscle systems. A neuromuscular adaptation could be occurring in the TMJ ID masticatory system affecting muscular actions and forces.     

Selective ablation of immature blood vessels in established human tumors follows vascular endothelial growth factor withdrawal

In the guinea pig, lateral deviation of the head is a cardinal symptom of the vestibular syndrome caused by unilateral labyrinthectomy. In the course of recovery from this syndrome (vestibular compensation), lateral deviation of the head disappears completely in 2-3 days. Because this symptom is known to be due to the lesion of the horizontal semicircular canal system, and since obliquus capitis inferior (OCI) muscle is activated predominantly by yaw rotation (horizontal vestibulocollic reflex), we hypothesized that changes in the activity of this muscle could be at least in part responsible for the lateral head deviation caused by unilateral labyrinthectomy. In order to test this hypothesis, electromyographic (EMG) activities of the right and left OCI muscles, as well as eye movements, were recorded in 12 head-fixed alert guinea pigs at various times after left surgical labyrinthectomy (performed with the animals under halothane anesthesia). After the operation, a decrease in tonic EMG activity was observed in the right (contralateral to the lesion) OCI muscle while an increase in tonic EMG activity was detected in the left (ipsilateral) OCI muscle. In addition, phasic changes in EMG activity associated with ocular nystagmic beats occurred in the OCI muscles. These phasic changes were in the opposite direction to those of the tonic changes. There were bursts of activity in the right OCI and pauses in the left OCI. From measurements of rectified averaged EMG activities which took into account both parts (tonic and phasic) of the phenomenon, it was concluded that the labyrinthectomy-induced asymmetry between the activities of the left and right OCI muscles was high enough and lasted long enough to be an important mechanism in the lateral deviation of the head caused by unilateral labyrinthectomy.     

Postural changes of the cervical spine in patients with nontoxic goiter

PURPOSE: To investigate differences in cervical spine posture and range of motion and self-reported neck pain and headache between patients with nontoxic goiter compared with a matched control group. DESIGN: An observational, controlled, blinded study. SETTING: The ambulatory outpatient facility of a university hospital. PARTICIPANTS: Twenty-five nontoxic goiter patients and 25 matched nongoiterous control subjects from the Department of Endocrinology. INTERVENTION: Participants were X-rayed from a lateral position in neutral, full flexion and full extension, and the radiographs were evaluated by a blinded examiner for anterior head carriage, maximal flexion, maximal extension and the extent and severity of any degenerative changes in the cervical spine. The degree of postural neck muscle tenderness was evaluated by a blinded rheumatologist using a validated Total Tenderness Score system. In addition, the two groups were compared for their self-reported frequency of neck pain and headaches. RESULTS: A significant increase in anterior head carriage was found among the goiter patients (p = .01), together with a corresponding decrease in flexion (p = .01), whereas the corresponding increase in extension was not statistically significant (p = .16). A higher prevalence of headaches was found in the goiter group (p = .06), but there was no difference in neck muscle tenderness (p = .40) or frequency of neck problems (p = .40) between the groups. The severity of degenerative changes in the cervical spine (p = .22) and the number of vertebral levels with degenerative changes (p = .13) were similar in the two groups. CONCLUSIONS: Goiters of > 100 g seem to alter the posture of the cervical spine, possibly resulting in a tendency for more frequent headaches. The changes do not seem to cause more neck pain, muscle tenderness or degeneration of the cervical spine.     

Vitamin A supplementation but not deworming improves growth of malnourished preschool children in eastern Zaire

14(R,S)-[18F]fluoro-6-thia-heptadecanoic acid (FTHA) has been recently introduced as a new tracer for fatty acid metabolism. Myocardial [18F]FTHA uptake is believed to reflect mainly beta-oxidation of the circulating free fatty acids (FFAs), since it is trapped in the mitochondria because subsequent steps of beta-oxidation are inhibited by sulfur heteroatom. We investigated [18F]FTHA kinetics in myocardial and skeletal muscle in vivo. METHODS: Two dynamic PET studies were performed in seven patients with stable coronary artery disease, once in the fasting state and once during euglycemic hyperinsulinemia (serum insulin approximately 60 mU/liter). The fractional [18F] FTHA uptake rates (Ki) were multiplied with serum FFA concentrations and were considered to represent FFA uptake. RESULTS: Serum FFA concentration decreased by 80% during insulin clamp. After tracer injection, rapid myocardial uptake was identified both in the fasting state and during insulin stimulation. The cardiac image quality was excellent in both occasions. In addition, femoral muscles were clearly visualized in both studies. The fractional myocardial [18F]FTHA uptake rates (Ki) in the normal myocardial regions were similar in the fasting state (0.11 +/- 0.04 ml/g/min (mean +/- s.d.) and during insulin clamp (0.12 +/- 0.03 ml/g/min; ns). The calculated myocardial FFA uptake was four times higher in the fasting state than during insulin clamp (5.8 +/- 1.7 versus 1.4 +/- 0.5 micromol/100 g/min, p < 0.005). The femoral muscle fractional [18F]FTHA uptake rates (Ki) were lower (0.0071 +/- 0.0014 ml/g/min) in the fasting state than during insulin clamp (0.0127 +/- 0.0036 ml/g/min; p = 0.03), but the estimated femoral muscle FFA uptake was three times higher in the fasting state (0.38 +/- 0.09 micromol/100 g/min) as compared to that during insulin clamp (0.12 +/- 0.05 micromol/100 g/min, p < 0.005). CONCLUSION: Fluorine-18-FTHA PET appears to be a feasible method to estimate fatty acid kinetics in myocardial and skeletal muscle. Physiologically reasonable rates of FFA uptake in myocardium and skeletal muscle were obtained. Furthermore, the uptake rates were suppressed in response to insulin both in the myocardial and femoral muscle as expected.     

Electromyographic and neuromuscular variables in post-polio subjects

OBJECTIVE: Post-polio subjects experience functional deterioration many years after developing acute poliomyelitis and have been shown previously to have a deficit in strength recovery after isometric activity. This study characterized the size and stability of the motor units in a group of post-polio subjects with macro and single fiber electromyography (EMG) and correlated these variables with isometric strength, endurance, "work capacity," and strength recovery after fatiguing isometric exercise. DESIGN: A cohort of 12 post-polio subjects was tested for neuromuscular function. Electromyographic variables were determined on a separate day. SETTING: Volunteers were recruited from the community and tested in our neuromuscular research laboratory. SUBJECTS: A volunteer sample was obtained from advertisements. All subjects acknowledged post-polio syndrome symptoms. MAIN OUTCOME MEASURES: Neuromuscular variables were isometric knee extension peak torque, endurance (time to exhaustion) at 40% of maximal torque, tension time index, and recovery of torque at 10 minutes. Electromyographic variables were macro EMG and single fiber EMG (percent blocking and jitter). RESULTS: Macro EMG amplitude was ninefold the control value, and both jitter and blocking were greatly increased in comparison to control values. Isometric strength significantly (p < .05) correlated negatively with macro EMG amplitude. CONCLUSIONS: The weakest subjects had the greatest number of muscle fibers within the motor unit (as measured by macro EMG amplitude). Jitter and blocking did not correlate with neuromuscular function.     

Behavioural response to pharmacologic manipulation of serotonin receptors in the genetically dystonic hamster

The genetically dystonic (dtsz) hamster is an autosomal recessive mutant that shares several features with paroxysmal dystonia, i.e., a subcategory of inherited idiopathic dystonia in humans. Because the serotonin (5-HT) system has been suggested to be involved in dystonia, we examined the functional responsiveness of the 5-HT system in dystonic hamsters by administering various 5-HT agonists and antagonists selective for different receptor subtypes and observing the effects on dystonic attacks as well as the behavioural responses associated with drug administration. Paradoxically, marked prodystonic effects (i.e., increased severity and/or decreased latency of dystonic attacks) were seen with both the selective 5-HT1A receptor agonist 8-hydroxy-2(di-n-propylamino)tetralin (8-OH-DPAT) and the selective and "silent" 5-HT1A receptor antagonist, N-tert-butyl-3[4-(2-methoxyphenyl)piperazin-1-yl]-2- phenylpropionamide [(+)-WAY-100135], whereas other 5-HT1A receptor antagonists, i.e., methyl 4[4-(4-[1,1,3-trioxo-2H-1,2-benzoiosothiazol-2-yl]butyl)-1- piperazinyl]1-H-indole-2-carboxylate (SDZ 216-525) and N1-bromoacetyl-N8-3'-(4-indolyloxy)-2'-hydroxypropyl-(Z)-1,8- diamino-p-methane (pindobind-5-HT1A) did not alter dystonia to any comparable extent. Because among these 5-HT1A receptor antagonists, (+)-WAY-100135 is the only drug known to be not only silent at postsynaptic but also presynaptic (somatodendritic) 5-HT1A receptors, the marked prodystonic effect of this drug could relate to increased 5-HT release as a result of the blockade of somatodendritic 5-HT1A receptors. The only 5-HT1A receptor antagonist that exerted antidystonic effects in hamsters was pindolol, which, however, could be related to its beta-adrenoceptor blocking action. The 5-HT1A receptor partial agonist ipsapirone exerted moderate prodystonic activity. Prodystonic activity was also determined for the mixed 5-HT1A/5-HT2 receptor agonist 5-methoxy-N,N-dimethyltryptamine, although this drug was less potent in this regard than 8-OH-DPAT. The 5-HT2 receptor agonist 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) exerted prodystonic effects in mutant hamsters, which, however, were also seen after the administration of the 5-HT2 receptor antagonist ritanserin. Collectively, the results of this study demonstrate that dystonia in genetically dystonic hamsters can be affected by pharmacologic manipulation of 5-HT receptors. The data may also indicate that dystonia is not a potential clinical application for selective 5-HT1A or 5-HT2 receptor antagonists.     

Cocontraction and phasic activity during GAIT in children with cerebral palsy

Simultaneous activity of agonist and antagonistic muscles during a task is known as cocontraction. The primary aim of the present study was to use a cocontraction index (CI) to quantify differences in EMG activity between a group of CP and control children at two different walking speeds. The secondary aim was to compare the amount of time the muscles were activated ("on" thresholds) between the groups. Seventeen subjects volunteered for the study. One group consisted of 9 (7M, 2F) children with CP (age 12.7 +/- 2.8 years, mean +/- SD). The second group consisted of 8 able-bodied controls (7M, 1F). The discontinuous submaximal treadmill walking protocol had two 4min stages at 0% gradient. Speeds selected were 3 km.h-1 and 90% of the pre-determined fastest walking speed (FWS). Two sites of CI were measured from the EMGs of tibialis anterior and soleus (leg) and vastus lateralis and hamstrings (thigh). Significantly (p < 0.05) higher CI values were noted for the CP subjects compared to the controls, irrespective of speed or cocontraction site and there was a significant (p < 0.05) increase in CI values with increased walking speed for both CP and control subjects. Phasic analyses for 5% max EMG and 10% max EMG "on" thresholds demonstrated significant (p < 0.05) main effects for group (CP subjects had a longer time period of muscle activation than controls) and speed (muscles were active longer at 90% FWS than 3 km.h-1). The precise mechanisms by which cocontraction contributes toward abnormal gait and wasted mechanical energy require further research incorporating both electromyographic and kinematic analysis.     

Effect of posture, route of respiration, and negative pressure on palatal muscle activity in humans

Sleep apnea is worse in the supine posture and is associated with retropalatal airway narrowing or occlusion. We have, therefore, examined the effects of posture, negative pressure, and route of respiration on palatal muscle activity in 13 nonsnoring awake male subjects by using electromyography. Electromyographic activity of the levator palatini and palatoglossus was expressed as a percentage of maximum activity. Both the levator palatini (P = 0.002) and palatoglossus (P = 0.002) exhibited phasic inspiratory activity. Overall, posture did not affect the levator palatini (F = 1.58; P = 0.23) or palatoglossus (F = 0.98; P = 0.34) activity, but analysis by route of respiration showed the palatoglossus to be more active when the subjects were nose breathing supine (F = 6.64; P = 0.02). Levator palatini activity was lower when nose breathing was compared with mouth breathing in both the erect and supine postures (F = 6.67; P < 0.02). Nose breathing with the mouth held open caused an increase in palatoglossal activity (P = 0.04). Negative-pressure application (0 to -12.5 cmH2O) caused significant increases in levator palatini (P < 0.001) and palatoglossus (P < 0.001) activity, 100 ms after pressure stimulus, irrespective of route. However, the palatoglossus required significantly greater negative pressures to cause activation when applied via the nose compared with the mouth (P < 0.05). These observations indicate that the levator palatini and palatglossus have respiratory activity and are reflexly activated by negative pressure.     

Coordination between glottic adductor muscle and diaphragm EMG activity in fetal lambs in utero

It has previously been reported that active glottic adduction is present during prolonged apneas but absent during periods of breathing movements in fetal lambs in utero. The present study was aimed at examining the precise coordination between fetal breathing movements [diaphragm electromyographic (EMG) activity (Di EMG)] and glottic adduction [thyroarytenoid muscle EMG activity (TA EMG)]. Electrodes for electroencephalogram, eye movements, TA EMG, and Di EMG and an arterial catheter were surgically implanted in fetal lambs 123-142 days postconception. Polygraphic recordings were performed without sedation while the ewe breathed room air (n = 11) or various gas mixtures (hypoxia, n = 5; hyperoxia, n = 4; hypercapnia, n = 5; hypercapnia+hyperoxia, n = 5). Tonic TA EMG was observed throughout >90% of apneas (>6 s) in both non-rapid-eye-movement and rapid-eye-movement sleep, and when Di EMG frequency decreased in rapid-eye-movement sleep. In all but two fetuses, TA EMG was immediately inhibited when Di EMG appeared. Altering blood gases did not modify these results. In conclusion, Di EMG and TA EMG are well coordinated in late gestation in fetal lambs, except in a few cases. These findings may have consequences for understanding the pathogenesis of mixed/obstructive apneas of prematurity.     

Heat-shock protein expression on the membrane of T cells undergoing apoptosis

OBJECTIVE: A variety of instruments have been applied to the measurement of activity, yet few, if any, have been validated specifically for older people with chronic pain. This study has sought to examine the utility of the Human Activity Profile (HAP) for describing activity in a sample drawn from a pain clinic for older people. DESIGN: The HAP was administered to 193 older pain clinic patients, 72 of whom completed the profile on a second occasion. A further 55 responses were collected from a group of community-dwelling volunteers. The factor structure of the HAP was tested using these 320 responses. The factors subsequently derived were compared with the Sickness Impact Profile (SIP) and the Barthel Index (BI). The discriminant validity of the HAP was examined by comparing factor scores for groups determined by gender, diagnosis, and status in the pain clinic. RESULTS: The 94 items of the HAP loaded onto 10 factors, which explained 63.7% of the variance. These factors demonstrated moderate associations with the BI and the subscales of the SIP. The factors discriminated between men and women (F[12.180] = 9.85. p < 0.000). Differences were also present between subjects with a musculoskeletal pain problem, postherpetic neuralgia, and pain-free volunteers (F[24.340] = 4.7. p < 0.000). Factor scores increased between pre- and postclinic assessments (F[12.60] = 4.79. p < 0.000). CONCLUSIONS: The HAP has demonstrated qualities which favor its adoption as an activity measure for older pain clinic patients.     

Step-tracking movements of the wrist. IV. Muscle activity associated with movements in different directions

We examined the patterns of muscle activity associated with multiple directions of step-tracking movements of the wrist in humans and monkeys. Human subjects made wrist movements to 12 different targets that required varying amounts of flexion-extension and radial-ulnar deviation. Wrist muscles displayed two patterns of electromyographic (EMG) modulation as movement direction changed: amplitude graded and temporally shifted. The amplitude-graded pattern was characterized by modulation of the quantity of muscle activity that occurred during two distinct time periods, an agonist burst interval that began before movement onset and an antagonist burst interval that began just after movement onset. The timing of muscle activity over the two intervals showed little variation with changes in movement direction. For some directions of movement, EMG activity was present over both time intervals, resulting in "double bursts." Modulation of activity during the agonist burst interval was particularly systematic and was well fit by a cosine function. In contrast, the temporally shifted pattern was characterized by a gradual change in the timing of a single burst of muscle activity. The burst occurred at a time intermediate between the agonist and antagonist burst intervals. The temporally shifted pattern was seen less frequently than the amplitude-graded pattern and was present only in selected wrist muscles for specific directions of movement. Monkeys made wrist movements to 8-16 different targets that required varying amounts of flexion-extension and radial-ulnar deviation. These movements were performed more slowly than those of human subjects. The wrist muscles of the monkeys we examined displayed the amplitude-graded pattern of activity but not the temporally shifted pattern. Stimulation of individual wrist muscles in monkeys resulted in wrist movements that were markedly curved, particularly for the wrist extensors. These results indicate that step-tracking movements of the wrist are generated mainly by using the amplitude-graded pattern to modulate muscle activity. We propose that this pattern reflects a central process that decomposes an intended movement into an agonist, "propulsive" component and an antagonist, "braking" component. Separate bursts of muscle activity then are generated to control each component. On the other hand, we argue that the temporally shifted pattern may function to reduce the amount of movement curvature associated with the activation of wrist muscles.     

Posture in patients with shoulder overuse injuries and healthy individuals

Assessment of posture is an integral component of patient evaluation with shoulder overuse injuries. However, the professional literature contains relatively few studies that have assessed the relationship between posture, function, and injury. The purpose of this study was to determine the relationship and differences in postural variables within and between subjects with overuse injuries to the shoulder of healthy subjects. Thirty patient subjects and 30 healthy subjects matched for age and gender were recruited. Scapular protraction and rotation, forward head position, midthoracic curvature, and passive humeral elevation in the plane of the scapula were measured randomly in standing. All measurement techniques were standardized and validated. Intrarater and interrater reliability for all clinical measures were established before data collection. Forward head position was significantly greater (p < .001) in the patient group than the healthy group; humeral elevation was significantly greater (p < .001) in the healthy group than in the patient group and in the uninvolved shoulders (p < .01) than the involved shoulders within the patient group. Scapular protraction, rotation, midthoracic curvature, and scapular symmetry were not significantly different between groups. Scapula protraction and rotation were significantly related (p < .05) in the patient group. No other postural variables were related. Conclusions regarding the influence of posture to shoulder injury are inconclusive based on several confounding variables that may have affected the outcome.     

Iodine-123-iodobenzamide binding in parkinsonism: reduction by dopamine agonists but not L-Dopa

The aim of the present study was to investigate the effect of treatment with L-Dopa or a dopamine agonist, or both, on specific striatal 123I-iodobenzamide (IBZM) binding using an intraindividual longitudinal design. METHOD: We prospectively studied the effect of dopaminomimetic treatment on specific [123I]IBZM binding measured by SPECT in 29 patients with a clinical diagnosis of Parkinson's disease, none of whom had previously received dopaminomimetic drugs. The patients had been selected on the basis of normal subsequent specific [123I]IBZM binding, semiquantitatively calculated as the basal ganglia/frontal cortex ratio, and a positive response to the dopamine agonist apomorphine before initiation of dopaminomimetic therapy. A second 123I-IBZM SPECT investigation was performed after 3-6 mo of treatment with L-Dopa or a dopamine agonist, or both. RESULTS: Specific [123I]IBZM binding was unchanged in 10 patients treated with L-Dopa alone. However, after treatment with a dopamine agonist there was a significant decline in specific [123I]IBZM binding (p < 0.05). After treatment with a combination of L-Dopa and a dopamine agonist, specific [123I]IBZM binding was reduced without reaching a level of significance (p = 0.08). CONCLUSION: Short-term treatment with a dopamine agonist but not with L-Dopa reduces specific [123I]IBZM binding. Therefore, before performing an [123I]IBZM SPECT scan in patients previously treated with dopaminomimetic drugs, dopamine agonists should be discontinued.     

Correlation of nicotinic binding with neurochemical markers in Alzheimer's disease

The loss of neocortical synapses that occurs in Alzheimer's disease (AD) has been shown to correlate with cognitive decline. In addition, marked losses in the cholinergic system in AD, specifically choline acetyltransferase (ChAT) activity and high affinity presynaptic neuronal nicotinic cholinergic receptors (nAChRs), have also been described. We hypothesized that in AD, the loss of [3H]-ligand binding to nAChRs, which are largely presynaptic, would correlate with changes in two other presynaptic markers: synaptophysin (Syn), a measure of synaptic density, and ChAT activity. The midfrontal (MF) cortex of 36 autopsy confirmed (NIA and CERAD criteria) AD patients (mean death age +/- SD 80.1 +/- 8.4 years) who met NINDS-ADRDA criteria for a clinical diagnosis of probable or possible AD, and 11 nondemented controls (mean death age +/- SD 77.9 +/- 8.0) were examined. Synapse counts were quantified by a dotimmunobinding assay for Syn. ChAT activity was assessed by standard biochemical assays. Nicotinic cholinergic receptor binding was assayed using the high affinity nicotinic agonist [3H]-(+/-)-epibatidine ([3H]-EPI). The mean +/- SD Syn in AD (83.4 +/- 31.9 arbitrary units (AU)/mg protein) was significantly lower than controls (126.1 +/- 19.9, p = 0.0003; t-test). The mean ChAT activity in AD (139.0 +/- 75.6 nmol ACh/hr/100 mg protein) was significantly lower than controls (219.6 +/- 70.8, p = 0.004). The mean [3H]-EPI total binding in AD (6.2 +/- 2.8 fmol/mg protein) was significantly lower than controls (14.8 +/- 3.2; p < 0.0001). Syn correlated with [3H]-EPI binding in AD (r = 0.48, p = 0.006; Pearson) but ChAT did not (r = -0.20, p = 0.34). We conclude that loss of high affinity nAChR binding correlates with loss of synapses in AD. The lack of correlation between [3H]-EPI binding and ChAT activity suggests that the targeted receptor populations may not be located exclusively on cholinergic neurons.