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PubMed1994

Rotational kinematics of the human vestibuloocular reflex. III. Listing's law.

1. Do slow phase eye velocities generated by the vestibuloocular reflex (VOR) depend on eye position? If the purpose of the VOR is simply to stabilize the retinal image, there can be no such dependence, because eye velocity must always be equal and opposite to head velocity. But if the VOR tolerates some retinal slip to achieve other goals, such as reducing eye velocity or following Listing's law, then one should see specific patterns of dependence. We examined VOR responses of human subjects to yaw, pitch, and roll rotation looking in various directions to quantify how the input-output properties of the VOR vary with eye position. 2. Eye rotation axes during yaw and pitch tilted in the same direction as the gaze line but only one-quarter as far on average. Thus, during yaw head rotation, the axis of eye rotation was roughly aligned with the head axis when the subject looked straight ahead, but tilted up when the gaze direction was up, and down when gaze was down. The amount of tilt varied between subjects, but on average a 30 degrees change in eye position caused a 7.5 degrees tilt in the eye rotation axis. During pitch, the eye axis tilted right when gaze was right and left when gaze was left, also moving 7.5 degrees on average for a 30 degrees change in the gaze direction. 3. During roll stimulation, the axis of eye rotation tilted in the opposite direction to the gaze line, and about one-half as far. On average, when the gaze line moved 30 degrees down, the eye rotation axis tilted 12.0 degrees up; when the gaze moved 30 degrees left, the eye axis tilted 15.3 degrees right. 4. It is often argued that the torsional VOR is weak because head rotation about the line of sight causes little image displacement on the fovea. But the line of sight is collinear with the torsional axis only when the subject looks straight ahead. Does the "weak axis" of the VOR stay collinear with the gaze line when the subject looks eccentrically? We calculated the axis of head rotation for which the VOR response is weakest and found that it does vary with eye position, but does not stay parallel with the gaze direction. When subjects looked straight ahead, the weak axis was roughly collinear with the gaze line; when gaze shifted eccentrically, the weak axis shifted in the same direction but only about one-half as far.(ABSTRACT TRUNCATED AT 400 WORDS)

Acceleration↗
PubMed2002

Collicular microstimulation during passive rotation does not generate fixed gaze shifts.

We investigated whether saccades evoked by electrical stimulation (E-saccades) in the superior colliculus can compensate for passive sinusoidal head rotation in yaw so as to keep the rapid gaze shift constant. After accounting for variations in E-saccade onset position, we found significant horizontal metric changes, proportional to head velocity, in 31 of 37 experiments in 2 monkeys. Vertical effects were small. In a substantial fraction of the experiments (14/37), these metric changes represented significant but often insufficient compensatory adjustments in the horizontal component, opposite to the direction of head movement. However, very robust violations of gaze-shift constancy were remarkably common: significant anticompensatory changes in the horizontal component occurred in 17/37 experiments. In these cases, typically involving larger E-saccades, the horizontal component increased in size with rotation into the half field containing the E-saccade and became smaller during opposite rotation. Further analysis showed that, instead of showing a dichotomy, the metric effect actually varied along a continuum from compensatory to strongly anticompensatory. In addition to these metric changes, we found a robust kinematic effect of head rotation in metrically matched E-saccades. In all experiments where the effect was significant (34/37), horizontal peak velocity increased for rotation into the half field where the E-saccade was directed and decreased for opposite rotation. This kinematic effect was again proportional to head velocity and predominant in the horizontal component. Comparison of yaw and pitch rotation at the same stimulation site showed that both expressions of vestibular-saccade interaction (metric and kinematic) tended to align with the direction of rotation. The component-specific nature of the modulation suggests that the effects may have been caused by convergence of saccadic and vestibular signals at a component-coding stage downstream of the colliculus. We suggest that the quick-phase system got access to the common pulse generator as soon as the collicular stimulation had opened the pause-cell gate. Adding such an anticompensatory signal would act to increase the E-saccade horizontal component when the monkey was rotated in the same direction and bring about a decrease in size and peak velocity when it was opposite. In the large majority of experiments the metric changes failed to maintain gaze-shift constancy, either because they were in the wrong direction or because they were too small. Possible reasons for this major departure from the properties of natural gaze shifts are discussed.

Animals↗
PubMed1993

Effects of stereoscopic and rotational displays in a three-dimensional path-tracing task.

A series of three experiments investigated the effectiveness of stereoscopic and rotational display techniques for the purpose of establishing human factors guidelines for the design of three-dimensional (3D) displays. In the described experiments, depth perception was evaluated by examining accuracy in a 3D path-tracing task, with stimulus displays resembling the structure of cerebral angiograms. The first experiment allowed subjects to control rotation in dynamic displays. The results indicated that performance improved using either technique relative to viewing two-dimensional (2D) displays. However, rotational displays were superior to stereoscopic displays, and performance was best when both techniques were combined. The second experiment compared subject-controlled rotation with observation of continuously rotating displays at different rates of rotation. Performance declined at faster rotation rates; however, there were no advantages of subject-controlled rotation. In the third experiment, performance in rotational displays was no better than that in stereoscopic displays enhanced with multiple static viewing angles. However, performance was always best when both 3D techniques were jointly implemented. The results are discussed in terms of the visual information available using either 3D display technique and are related to the weighted additive model of depth perception.

Adult↗
PubMed2005

Patterns of vascular and anatomical response after rotator cuff repair.

BACKGROUND: It has been assumed that a robust vascular response at the tendon to bone interface during rotator cuff repairs is an integral part to the healing process. There are few studies that have explored this in an in-vivo prospective fashion. PURPOSE: To prospectively characterize vascular and anatomical patterns in repaired rotator cuff tendons using Power Doppler sonography in a double-blinded fashion. STUDY DESIGN: Case control study; Level of evidence, 3. METHODS: Fifty patients undergoing rotator cuff repair were enrolled: 28 mini-open, 14 open, and 8 arthroscopic repairs; 20 patients were controls. Patients underwent Power Doppler sonography at 6 weeks, 3 months, and 6 months postoperatively. Power Doppler sonography analysis examined 6 areas of the rotator cuff repair: discretely marginated intrasubstance, partial-thickness defects, full-thickness defects, focal thinning of repair, presence of bursal or joint fluid, and location of anchors. A subjective scoring system assessed blood flow in each region. RESULTS: There was a predictable, significant decrease in vascular scores after rotator cuff repair over time. The mean vascular score was 11.6 at 6 weeks, 8.3 at 3 months, 7.0 at 6 months, and 2.4 for controls. There was a significant difference (P < .05) in vascular recruitment scores between each time period, with the most robust flow at the peritendinous region. The lowest vascular score was at the anchor site or cancellous trough. Forty-eight percent of the patients had a rotator cuff repair defect postoperatively. These findings did not correlate with functional assessment and outcome at 6 months. There was no significant difference in vascular scores between the defect and no-defect groups. Mean University of California, Los Angeles; L'Insalata; and American Shoulder and Elbow Surgeons scores at 6 months were 28.6, 86.3, and 81.5, respectively. Thirty-three percent of asymptomatic controls had a rotator cuff tear that averaged 7.6 x 7.1 mm. CONCLUSION: The robust vascular response dropped with time, which is not seen in asymptomatic shoulders. Nearly half of the patients demonstrated persistent rotator cuff defects after rotator cuff repair that did not correlate with functional outcome and physical findings at 6 months.

Adult↗
PubMed2006

Arthroscopic anteroinferior suture plication resulting in decreased glenohumeral translation and external rotation. Study of a cadaver model.

BACKGROUND: The consequences of arthroscopic plication for the treatment of anterior shoulder instability are unknown. The purpose of this study was to evaluate the effects of arthroscopic plication on glenohumeral translation, the rotational range of motion, and the positions of the glenohumeral center of rotation. METHODS: Six cadaver shoulders were tested in the intact state, after simulation of anterior instability by anterior capsular stretching, after creation of arthroscopic portals, and following a 10-mm anteroinferior arthroscopic suture plication. Capsulolabral build-up was measured to quantify the increase after plication. RESULTS: Stretching resulted in a significant increase, compared with the intact state, in external rotation (mean increase, 23.2 degrees [14.3%]; p < 0.001) but not in glenohumeral translation (mean increase, 0.8 mm [7.4%] under a 20-N translational load; p = 0.06). After plication, external rotation decreased significantly (by 12.6 degrees [6.7%], p = 0.003) compared with that following the stretching. After plication, the glenohumeral center of rotation was significantly shifted posteriorly at 60 degrees , 90 degrees , and 120 degrees of external rotation and inferiorly at 90 degrees and 120 degrees . Plication also resulted in significant decreases in anterior translation (mean decrease, 61.1% under a 15-N translational load and 49.8% under a 20-N translational load; p < 0.001), posterior translation (mean decrease, 11.4% under a 15-N translational load and 13.1% under a 20-N translational load; p = 0.002 and p < 0.001, respectively), and inferior translation (mean decrease, 3.2% under a 20-N load; p = 0.04). The height of the capsulolabral "bumper" increased from 2.9 mm in the intact state to 6.4 mm following plication (p = 0.001). CONCLUSIONS: Arthroscopic anteroinferior plication effectively reduces anterior translation and external rotation. Capsulolabral buildup may help limit anterior translation without affecting rotation. Plication resulted in a shift of the glenohumeral center of rotation posteriorly and inferiorly.

Aged↗
PubMed1995

Association of sonographically detected subacromial/subdeltoid bursal effusion and intraarticular fluid with rotator cuff tear.

OBJECTIVE: Although an association between sonographically detected joint fluid and rotator cuff disease has been reported, the significance of sonographically detected subacromial/subdeltoid bursal effusion has not been studied. We examined a group of patients who had shoulder sonography and surgery to determine the association between bursal and joint effusion and surgically proved tears of the rotator cuff. MATERIALS AND METHODS: We retrospectively reviewed the preoperative shoulder sonography reports of 163 patients for the presence of fluid within the subacromial/subdeltoid bursa or glenohumeral joint. Surgical reports were obtained to determine the status of the rotator cuff. The sonographic reports of 232 asymptomatic shoulders were also reviewed to determine the prevalence of fluid within the subacromial/subdeltoid bursa or the glenohumeral joint. RESULTS: Sixty-seven (41%) of the 163 patients had a joint effusion, bursal fluid, or both. Joint effusion alone was seen in 35 patients. Fourteen of these had a normal rotator cuff at surgery, and 21 had a rotator cuff tear (sensitivity, 22%; specificity, 79%; positive predictive value, 60%). Bursal fluid alone was seen in 10 patients, seven of whom had a rotator cuff tear (sensitivity, 7%; specificity, 96%; positive predictive value, 70%). In 22 patients, fluid was seen in both the bursa and the joint; 21 had surgically proved rotator cuff tears (sensitivity, 22%; specificity, 99%; positive predictive value, 95%). Of the 232 asymptomatic shoulders, 16 (6.9%) had isolated joint effusions, eight (3.4%) had isolated bursal effusions, and four (1.7%) had both joint and bursal effusions. CONCLUSION: The sonographic finding of intraarticular fluid alone (without bursal fluid) has both a low sensitivity and a low specificity for the diagnosis of rotator cuff tears. However, the finding of fluid in the subacromial/subdeltoid bursa, especially when combined with a joint effusion, is highly specific and has a high positive predictive value for associated rotator cuff tears. Sonographically detected fluid in both the joint and the bursa is an uncommon finding in asymptomatic shoulders. The sonographic observation of fluid in the subacromial bursa, either isolated or combined with a joint effusion, should prompt a careful evaluation of the supraspinatus tendon for tear.

Acromion↗
PubMed1995

[Analysis of temporal factor affecting hepatic illusion of a rotated disk].

Twenty-four subjects experienced Cormack's illusion by rotating a disk using fingers of both hands with some pauses inserted during the rotation. Variables were durations for rotating a disk and pause. The illusion magnitude was measured just before each pause. The first experiment showed that the illusion magnitude decreased with increasing the pause. The second experiment showed that there was no difference in illusion magnitude between 5- and 20-second conditions of pause for 20-second rotating duration, although the magnitude was smaller for 20-second pause than that for 5-second pause under the condition of 5-second rotating duration. The experiment also showed that the final magnitude did not depend on whether the magnitude was measured every five seconds or only once at the end of the rotation. The results indicate that pause during rotation contributes to recovering from adaptation due to the rotation and that the effect of pause depends on the duration of rotation. The results also indicate that the increasing illusion magnitude with time is not an artifact due to the method of measuring the magnitude.

Adaptation, Psychological↗
PubMed1999

Eye movements during torso rotations in labyrinthine-defective subjects.

The aim of this study was to examine whether the chronic loss of vestibular function modifies perceptual and oculomotor responses during torso rotations in darkness. Subjects (4 patients with complete vestibular loss and 7 healthy volunteers) were seated on a rotating chair. Stimuli consisted of sinusoidal chair rotations (+/-30 degrees, 0.1 Hz and 0.011 Hz). We used 2 conditions: space stationary head (neck stimulation) and space stationary head and shoulders (torso stimulation). Horizontal eye deviations and slow component of eye movements were analysed. The results showed that eye movements and perception of head motion in space during neck stimulation were similar to those during torso stimulation both in normal and labyrinthine-defective (LD) subjects. During low-frequency chair rotations (0.011 Hz) all subjects perceived illusory head or head and shoulder rotation in space (as if the lower part of the body was stationary relative to the room) and shifted their gaze in the direction of illusory head rotation. In these conditions there was no significant difference in eye movements between normal and LD subjects. During higher frequency chair rotations (0.1 Hz), LD subjects had significantly larger eye deviations as well as increases in the gain of the slow component of eye movements relative to normals. In these conditions patients mostly perceived illusory head or head and shoulder rotation in space while normal subjects mainly perceived the head as stationary in space. The results indicate that 1) neck and torso rotations can evoke similar ocular responses in LD subjects, 2) the chronic loss of vestibular function modifies the representation of axial body segment motion relative to space.

Aged↗
PubMed2000

Torsional dynamics and cross-coupling in the human vestibulo-ocular reflex during active head rotation.

Six subjects fixated an imagined space-fixed target in darkness, or a visible target against a structured visual background, while rotating their heads actively in yaw, pitch and roll at four different frequencies, from 0.3 to 2.4 Hz. We used search coils to measure the 3-dimensional rotations of the head and eye, and described the relation between them--the input-output function of the rotational vestibulo-ocular reflex (VOR)--using gain matrices. We found consistent cross-coupling in which torsional head rotation evoked horizontal eye rotation. The reason may be that the eyes are above the axis of torsional head rotation, and therefore may translate horizontally during the head motion, so the VOR rotates them horizontally to compensate. Torsional gain was lower than horizontal or vertical, more variable from subject to subject and decreased at low frequencies. One reason for the low gain may be that torsional head rotation produces little retinal slip near the fovea; hence little compensatory eye motion is needed, and so the VOR reduces its torsional gain to save energy or to approximate Listing's law by keeping ocular torsion near zero. In addition, the human VOR has little experience with purely torsional head rotations and so its adaptive networks may be poorly trained for such stimuli. The drop in torsional gain at low frequencies can be explained based on the leak in the neural integrator that helps convert torsional eye-velocity commands into eye-position commands.

Adult↗
PubMed1999

Action sites of rotation and unit firing induced by l-stepholidine and DA agonists in basal ganglia of 6-OHDA-lesioned rats.

AIM: To elucidate the action sites of l-stepholidine (SPD) in the basal ganglia. METHODS: Counting the rotations after intra-nucleus microinjection and recording the neuron firing by microiontophoresis of SPD and DA agonists in the basal ganglia of 6-hydroxydopamine (6-OHDA)-lesioned rats. RESULTS: The DA immunoreactive substance was markedly reduced in the 6-OHDA-lesioned rats. The intra-neostriatum microinjection of apomorphine (Apo, D1/D2), SK&F 38393 (D1), and SPD elicited remarkable rotation, and the characteristics of SK&F 38393-produced rotation were of long latency and long duration. The intra-substantia nigra pars reticulata (SNR) injection of Apo, SK&F 38393, and SPD induced the rotation response, while the selective D2 agonist quinpirole hydrochloride (Ly171555) did not because of scarce D2 receptors in the SNR. The intraglobus pallidus (GP) injection of DA agonists and SPD failed to evoke rotation, but the GP nucleus still had the contribution to rotation elicited by i.p. injection of DA agonists and SPD in the 6-OHDA-lesioned rats with successive kainic acid (KA) lesion. Besides, the successive lesion of entopeduncular nucleus (EP) on rotation was less important than that of GP nucleus. The microiontophoresis of Apo and SPD into the SNR could evoke the neuron firing, but failed to activate the GP neurons, which were activated by sodium glutamate (Glu) and inhibited by gamma-aminobutyric acid (GABA). CONCLUSION: The action sites of SPD-induced rotation and neuron firing via the D1 receptors are in the neostriatum and SNR instead of GP. The direct neurocircuit through SNR is the most important for rotation of 6-OHDA-lesioned rats.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1997

Displacement of statoliths in Chara rhizoids during horizontal rotation on clinostats.

The basipetal movement of statoliths in Chara rhizoids, similar to that during parabolic flights of TEXUS rockets occurs also during rotation on clinostats. Within 15 min on fast-rotating clinostat, the distance between the center of the statolith complex and the cell vertex increases for 60% of that in positively gravitropic downward growing rhizoids. Cytochalasin D experiments confirm that the movement of statoliths is actin-dependent and the actin filaments exert basipetal forces on statoliths in gravity field. The clinostat and/or cytochalasin experiments confirm the suggestion that on earth the position of statoliths depends on the balance of the gravitational force and the counteracting force mediated by actin filaments. The statolith center keeps a stable position during about 30 min on a fast-rotating clinostat, i.e. it is then in a new dynamically stable state. This new state is achieved 15 min after the basipetal acting filament-mediated force has been disturbed by clinostatting. Further experiments on the fast-rotating clinostat show that this new position brings about a reorganization of actin filaments which makes the process of acropetal transport of statoliths possible. The amplitude of particle oscillatory movement decreases as the rotational speed of the clinostat increases. This explains the differences of the results obtained from the experiments on fast-rotating and slow-rotating clinostats. It should be kept in mind that rhizoids are unicellular. The fast-rotating clinostat is suitable for simulation of conditions without gravity when a rhizoid is on the axis of rotation. The interaction of statoliths and actin filaments at zero gravity can be studied by means of such a clinostat.

Actin Cytoskeleton↗
PubMed2003

[Effect of femoral rotation on hip bone mineral density measurement].

OBJECTIVE: To measure hip bone mineral density (BMD) on different femoral rotations and to identify the influence of femoral rotation during hip densitometry. METHODS: Forty women were recruited at the out-department of orthopedic, with the average age of 60.7 years (45-85 years), the average height of 161.8 cm (150-175 cm), and the average weight of 67.4 kg (48-80 kg). BMD measurement of hip was done in neutral position (0 degrees), 15 degrees and 30 degrees of internal rotation under quality control of DXA machine. All the subjects were asked to get down scan table and reposition after each measuring in different rotation. RESULTS: Hip BMD of proximal femur (femoral neck, Ward's area and trochanter region) have significant variations in measurement (P < 0.01) among neutral position, 15 degrees and 30 degrees of internal rotation. There were more BMD change at the cancellous region (Ward's triangle and trochanter region) than at cortical bone area (femoral neck region). Statistical analysis showed a significant positive correlation for hip BMD change between neutral degrees to 15 degrees of internal rotation and 15 degrees to 30 degrees of internal rotation. But no correlation between neutral degrees to 30 degrees of internal rotation for hip BMD change. CONCLUSIONS: Femoral rotation was shown to have a significant effect on hip BMD measurements. Cortical bone region of hip have a less BMD change than cancellous bone region. Proper positioning of the femur during scan can improve precision significantly.

Absorptiometry, Photon↗
PubMed1992

Isokinetic and isometric measurement of strength of external rotation and abduction of the shoulder.

The strength of active external rotation and of abduction of the shoulder when the humerus was in the plane of the scapula (30 degrees of horizontal flexion anterior to the coronal plane) was measured isokinetically and isometrically in thirty-nine normal volunteers, who were stratified by age and sex. The angles at which peak torque was produced were similar when tested isokinetically and isometrically; these angles were similar for external rotation (at 60 and 30 degrees of internal rotation) and for abduction (at 30 and 60 degrees of abduction). Isometric peak torque was greater than slow-speed (90 degrees per second) isokinetic peak torque, which in turn was greater than fast-speed (210 degrees per second) isokinetic peak torque. There were highly significant differences in strength, measured isokinetically and isometrically, between younger and older men and between older men and older women. The variability of normal values for torque was similar in each group. Repeat testing demonstrated a high reliability of isokinetic measurements and of isometric measurements at angles within the range of the production of peak torque. Complete testing was performed in four normal volunteers before and after a block of the suprascapular nerve. The supraspinatus and infraspinatus components of the rotator cuff contributed a variable proportion to the total strength of abduction (25 to 50 per cent) and external rotation (50 to 75 per cent) throughout the range of motion. This study demonstrated that both isokinetic and isometric testing in the scapular plane are valid methods for measurement of the strength of external rotation and abduction of the shoulder. The data support standardization of the positions for testing the strength of motions of the shoulder: isometric strength of external rotation should be measured in the scapular plane with the shoulder in 45 degrees of abduction and 45 degrees of internal rotation; isometric strength of abduction, in the scapular plane with the shoulder in 45 degrees of abduction; and isokinetic strength of external rotation and abduction, in the scapular plane at 90 degrees per second.

Adult↗
PubMed1988

Kinematic analysis of the instant centers of rotation of the equine metacarpophalangeal joint.

A kinematic analysis of the instant centers of rotation analysis was performed on 21 metacarpophalangeal joints from 11 horses. Manual and computerized methods were used to locate the instant center of rotation on photocopies of transparent composite tracings of a series of radiographs of each joint. The instant centers of rotation of the proximal phalanx about the distal portion of the third metacarpal bone were located consistently on or near the eminence for attachment of the collateral ligaments. The instant centers of rotation of the sesamoids about the distal portion of the third metacarpal bone were consistently located near the dorsal articular margin of the distal portion of the third metacarpal bone. Rotation of the joint as it extended caused minor variation in radiographic projection. This variation in radiographic projection limited the precision of the analysis of the instant center of rotation and prevented the identification of a single instant center of rotation or an instant center of rotation pathway for the articulation of the proximal phalanx or the proximal sesamoids with the distal portion of the third metacarpal bone. The articular surface velocity vectors determined from the instant centers of rotation indicated that the joint surfaces slide on each other. The motion of the joint caused compression at the dorsal articular margins at maximal extension and thereby limited further extension. At this degree of extension, the proximal sesamoids articulated only with the proximal sesamoid-metacarpal articular surface of the distal portion of the third metacarpal bone.

Animals↗
PubMed1988

[Arm rotation during abduction of the shoulder in the scapular plane].

The arm rotation during abduction of the shoulder in the scapular plane was investigated in 11 volunteers. The degree and direction of the arm rotation were measured using five potentiometers, and were analysed by a computer system. In eight volunteers, the arm always rotated externally (1.5 degrees-4.9 degrees of rotation for each 10 degrees of abduction); in one volunteer it rotated internally (0.9 degree of rotation for each 10 degrees of abduction); and in the two remaining volunteers it rotated without showing a constant tendency during the abduction. The degree of arm rotation was correlated to the tilting angle of the acromial articular surface which was measured radiographically. A tendency of external rotation of the arm is suggested to occur during abduction in the scapular plane along with the decrease of the tilting angle of the acromial articular surface.

Adult↗
PubMed1979

Palate morphogenesis. IV. Effects of serotonin and its antagonists on rotation in embryo culture.

Previous studies have localized non-muscle contractile systems in the posterior (region 2) and the anterior (region 3) ends of mouse palates at the time of shelf movement. In order to determine whether these contractile systems function in shelf rotation, effects of pharmacologic agents have been analyzed in embryo culture. First, it was shown that the posterior end of the palate rotates before the anterior end, and its rotation in culture was proportionally greater as development of the embryo progressed. Generally, the posterior end of the palate was more easily inhibited in embryo culture than the anterior end. Serotonin at 10(-8) M to 10(-5) M was shown to significantly stimulate rotation at the anterior end of the palate after 2 h in embryo culture. The effect on the posterior palate was less pronounced. To investigate further the role of this neurotransmitter on palate shelf rotation, serotonin antagonists were employed. Methysergide (10(-4) M) inhibited anterior shelf rotation to 12% of control values (P less than 0.005), while not significantly affecting the posterior end. Ergotamine (10(-6) M) significantly inhibited the stimulation induced by 10(-5) M serotonin (P less than 0.025). Cyproheptadine (10(-9) M) partially inhibited anterior and posterior shelf rotation in embryo culture. When injected into the pregnant dam, cyproheptadine partially inhibited shelf rotation and fusion. The palate was examined histologically after embryo culture. In the presence of 10(-4) M methysergide, the elongated contractile cells in region 3 at the anterior and midpalatal mesenchyme were prevented from rounding. Thus, serotonin may be regulating rotation of the anterior end of the palate by an effect on cell-mediated process.

Animals↗
PubMed1980

Palate morphogenesis. V. Effects of cholinergic agonists and antagonists on rotation in embryo culture.

Morphological studies have shown that the pterygopalatine ganglion in the day-14.5 mouse palatal shelf lies adjacent to the putative contractile system of region-2 cells in the posterior palate. It is of interest to learn whether the ganglion could influence rotation of the palate. Results of embryo culture experiments showed that acetylcholine appeared to play a role in posterior shelf rotation since cholinergic agents (pyridostigmine, bethanechol and carbachol) stimulated elevation of that end of the palate. To characterize the putative receptors mediating the effects of the cholinergic agonists on palate shelf elevation, muscarinic or nicotinic antagonists were introduced into the emrbyo culture system. Atropine, a muscarinic blocking agent, did not produce any significant effect on palate shelf rotation when tested in overnight and 2 h embryo cultures at 3 X 10(-5) M and 10(-4) M, respectively. Neither did atropine inhibit significantly the stimulation produced by 10(-8) M bethanechol, Thus, the cholinergic effect was probably not on muscarinic receptors of the contractile system. However, hexamethonium, a nicotinic antagonist, at 10(-6) M and 10(-4) M profoundly inhibited posterior shelf rotation to about 35% of the control value in a 2 h incubation. In addition, 10(-4) M hexamethonium inhibited posterior palate rotation to 11% of the control value after overnight culture. Furthermore, hexamethonium was able to reverse the stimulation of posterior rotation produced by carbachol. Partial inhibition of palate rotation by hexamethonium was also demonstrated when pregnant dams were injected with drug at doses approximately corresponding to 10(-6) and 10(-4) M. Hexamethonium treatment resulted in approximately 30% of the palates not completely rotated at day 15.5 compared to only 9.3% in the control. Hexamethoniuim also produced a significant increase in the palate gap and a comparable decrease in palate fusion. These effects were slightly greater at the posterior end of the palate. Thus, the cholinergic ganglion in the posterior palate may play a role in regulating shelf rotation at that end through a nicotinic pathway.

Acetylcholinesterase↗
PubMed1996

[Controversial rotation function of certain muscles in the hip joint].

The disputed rotating function of certain muscles in the hip joint. A device constructed for that study allows to determine the rotating function of the iliopsoas muscle as well as of the uniarticular adductor muscles of the thigh in every position of the hip joint by the method of threads. The iliac muscle rotates the thigh inward in every position of flexion/extension or abduction/adduction of the hip joint. The adductor magnus muscle always is a lateral rotator by those fibres which are inserted into the medical edge of the linea aspera, while the fibres attached to the adductor tubercle rotate the thigh inward. The psoas major, pectineus, adductor longus and adductor brevis muscles are able to rotate the thigh inward as well as outward. Their rotating function depends on the specific position of flexion/extension and abduction/adduction of the hip joint: Flexion and abduction intensify the lateral rotating function of these muscles, extension and adduction intensify the medial rotating function.

Aged↗