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PubMed1999

Preliminary CT study of C1-C2 rotational mobility in normal subjects.

A CT study of normal atlanto-axial (C1-C2) rotary mobility was carried out on ten normal immature subjects. In order to determine the limits of normality, the ten children underwent clinical and radiological examination. The clinical study included checking for objective signs of joint laxity and measurement of rotational neck mobility. The radiological study included standard lateral radiographs in neutral and maximal flexion positions and a CT scan taken in maximal left and right side rotation at the C1-C2 articular processes joint. The superpositioning of the images taken in every rotational direction showed, in all ten children, a wide contact loss between the C1-C2 corresponding facets, ranging from 74 to 85% of the total articular surface. The report on these images, carried out by three independent radiologists, concluded that there was a rotary subluxation in all cases. In the ten children studied, there were no significant differences with regard to neck mobility or laxity signs in clinical or standard X-ray examination. Our results lead us to conclude that, except for complete C1-C2 rotational dislocation with facet interlocking, a CT scan showing a wide - but incomplete - rotational facet displacement is not sufficient to define a status of subluxation. This leads us to perceive that there is a risk of overdiagnosis when evaluating upper cervical spine rotational problems in children. The concept of both rotary C1-C2 fixation and subluxation should be revised.

Atlanto-Axial Joint↗
PubMed2003

Linkage guide for rotational alignment during total knee arthroplasty.

A linkage guide was devised for use in conjunction with knee arthroplasty instruments to achieve proper component rotation. The femoral component was rotationally aligned to the surgical epicondylar axis using one guide. The other guides were used after all bone surfaces were cut and soft tissue balancing was completed. A Kirschner wire was guided into the proximal tibial aspect parallel to the sagittal plane of the femoral component with the patella in its normal position and the knee in full extension. The wire was used as a reference to determine tibial component rotation. The relative rotational alignment of 21 knees in 19 patients who had undergone cruciate-retaining total knee arthroplasty utilizing this guide was assessed using the modified Eckhoff method. The results of radiographic analysis were compared with those in a control group of 25 knees where the guide was not employed. The external rotation of the femoral component relative to the tibial component was 1.3 degrees +/- 2.0 degrees (mean +/- SD) in the guided group and 1.1 degrees +/- 4.4 degrees in the control group. The relative rotational angle was significantly more consistent using the guide. Implant malrotation can be reduced using our technique.

Arthroplasty, Replacement, Knee↗
PubMed1998

Reliability of the anteroposterior axis and the posterior condylar axis for determining rotational alignment of the femoral component in total knee arthroplasty.

We examined the reliability of the anteroposterior and posterior condylar axes for determining rotational alignment of the femoral component in total knee arthroplasty (TKA). A computed tomography scan was taken at the level of the femoral epicondyle in 84 knees (27 varus knees with medial femorotibial arthritis (FT-OA) in 26 patients, 17 knees with patellofemoral arthritis in 14 patients, and 40 normal knees in 40 volunteers). On the image, an anteroposterior axis, a line perpendicular to the anteroposterior axis, an epicondylar axis and a posterior condylar axis were drawn, and the relationship between the three axes was assessed. The mean values for the 84 knees were evaluated, and the posterior condylar axis was 6.0 degrees +/- 2.4 degrees internally rotated relative to the epicondylar axis, while the line perpendicular to the anteroposterior axis was 1.4 degrees +/- 3.3 degrees internally rotated relative to the epicondylar axis. The internal rotation angle of the posterior condylar axis relative to the epicondylar axis was 6.2 degrees +/- 1.9 degrees in the knees with medial femorotibial arthritis, 6.4 degrees +/- 2.4 degrees in the knees with patellofemoral arthritis, and 5.8 degrees +/- 2.7 degrees in the normal knees, showing consistent values in normal and osteoarthritic knees. The internal rotation angle of the line perpendicular to the anteroposterior axis relative to the epicondylar axis was 0.1 degrees +/- 3.3 degrees, 1.3 degrees +/- 3. 3 degrees, and 2.3 degrees +/- 3.1 degrees in the three groups, respectively (i.e., there were significant differences between the medial FT-OA knees and the normal knees). The results demonstrated that the anteroposterior axis was rotated externally to a significant degree in medial FT-OA knees and was less reliable than the posterior condylar axis for use in alignment for TKA on medial FT-OA knees.

Aged↗
PubMed1985

The influence of lipid composition and lectin-glycophorin interaction on the rotational diffusion of glycophorin in vesicles, as measured by time-resolved phosphorescence depolarization.

The rotational mobility of glycophorin in various lipid vesicles was studied, using time-resolved measurements of the depolarization of laser flash excited phosphorescence of glycophorin labelled with the triplet probe erythrosin. With the exception of dimyristoylphosphatidylcholine at the phase transition no phosphorescence depolarization decays were observed in the 1-300 microseconds time interval following the laser flash. Instead, a constant anisotropy level was observed, with two distinct values depending on the experimental system. In liquid-crystalline bilayers of dioleoylphosphatidylcholine, bovine brain phosphatidylserine and dimyristolyphosphatidylcholine, the anisotropy was 0.01. This was increased to 0.03 upon addition of wheat germ agglutinin which aggregates glycophorin. In the case of gel state dimyristoylphosphatidylcholine and liquid-crystalline dioleoylphosphatidylethanolamine the anisotropy also amounted to 0.03. Experiments with glycerol to vary the viscosity of the medium, and theoretical considerations, exclude the possibility that these different anisotropy levels are related to differences in motional properties of the entire protein/lipid vesicles. These results strongly suggest that the anisotropy level of 0.03 corresponds to slowly rotating glycophorin (rotational relaxation time greater than 0.3 ms) while the anisotropy level of 0.01 corresponds to fast rotating glycophorin (rotational correlation time less than 1 microseconds). The difference in glycophorin mobility is discussed in terms of aggregation state of the protein, lipid composition of the vesicle bilayer and membrane viscosity. The observed differences in rotational mobility of glycophorin in glycophorin/dioleoylphosphatidylcholine vesicles, glycophorin/bovine heart phosphatidylserine vesicles as compared to glycophorin/dioleoylphosphatidylethanolamine vesicles are not in quantitative agreement with the relative size of the intramembrane particles in these systems as revealed by freeze-fracture electron microscopy.

Animals↗
PubMed1983

Chlorpromazine methiodide acts at the vestibular nuclear complex to induce barrel rotation in the rat.

Barrel rotation is a unique motor response observed in rats in which, following an intracerebral injection, the animal develops a twist about the long axis and rolls laterally repeatedly. The response was first described following injection of somatostatin. We have previously shown that 'experimental dystonia' in rats induced by intraventricular chlorpromazine methiodide (CPZMI) is identical to barrel rotation, and that it is due to an antimuscarinic effect. The purpose of the present study was to investigate the neuroanatomical basis of CPZMI-induced rotation. We injected CPZMI in 3 microliters into right lateral and IVth ventricle and found that IVth ventricle injections were significantly more likely to induce rotation. Nuclear groups adjacent to the IVth ventricle, which are rich in muscarinic cholinergic receptors, include locus coeruleus and vestibular nuclear complex (VNC). We found that only VNC injections induced rotation. Only certain control compounds injected into VNC elicited the response. We conclude that barrel rotation has a specific neuroanatomical basis, involving central vestibular mechanisms, and that it has a specific pharmacologic basis.

Animals↗
PubMed1983

Nystagmus generated by sinusoidal pitch while rotating.

Sinusoidal pitch while rotating about a vertical axis in darkness causes continuous horizontal compensatory nystagmus in the monkey which persists for the duration of stimulation. The steady-state velocity sums with post-rotatory nystagmus to reduce or cancel it, suggesting involvement of the velocity storage mechanism. Analysis of the labyrinthine excitation during pitch while rotating suggests that the vertical canals play a predominant role in generating the response. Effects of selective labyrinthine lesions are in agreement with this hypothesis. Plugging the lateral canals, leaving the vertical canals intact, blocked the initial rapid response at the onset of rotation, but did not interrupt the continuous nystagmus induced by pitch while rotating. On the other hand, plugging the vertical canals abolished the response. If the lateral canal nerves were cut so that the velocity storage mechanism was inactivated, the continuous response to pitch while rotating also disappeared. The dominant labyrinth activation responsible for the nystagmus during pitching while rotating appears to arise in the vertical semicircular canals and to couple to the oculomotor system through the velocity storage mechanism.

Animals↗
PubMed1991

Partial lesion of the substantia nigra: relation between extent of lesion and rotational behavior.

Recent work, largely carried out in primate models of Parkinson's disease (PD), indicates that residual dopaminergic neurons in the midbrain and their axons to the nucleus accumbens and striatum can be stimulated to sprout collateral axons, reinnervate the striatum, and cause a behavioral recovery. We sought to create a partial lesion model of PD in the rat that would (i) mimic the pattern of cell loss in human patients in early stages of PD, and (ii) permit examination of experimental manipulations that promote sprouting of axons of the surviving dopaminergic cells in the midbrain. Rats with unilateral 6-hydroxydopamine (6-OHDA) lesions of the substantia nigra pars compacta (SNpc) were tested weekly for rotational asymmetry following administration of apomorphine or amphetamine. After completion of behavioral testing, the animals were sacrificed and the brains immunolabeled for tyrosine hydroxylase (TH). Analysis of anatomical and behavioral data revealed a strong correlation between number of remaining TH-immunoreactive cells in the SNpc and the number of rotations induced by apomorphine. There was no significant correlation between number of remaining TH-immunoreactive nigral neurons and number of rotations induced by amphetamine. We also examined the relation between area in the denervated striatum with remaining TH-immunoreactive axons, number of TH-immunoreactive cells in the lesioned SNpc, and rotational behavior. As expected, there was a strong correlation between area innervated by TH-immunoreactive axons and number of remaining TH-immunoreactive neurons in the lesioned SNpc. Total extent of innervation was also correlated with number of apomorphine-induced rotations but not with number of amphetamine-induced rotations.(ABSTRACT TRUNCATED AT 250 WORDS)

Amphetamine↗
PubMed1994

Transection of corticostriatal afferents abolishes the hyperexpression of Fos and counteracts the development of rotational overcompensation induced by intrastriatal dopamine-rich grafts when challenged with amphetamine.

The present study was carried out to test whether the abnormally high striatal Fos activation induced by amphetamine and the overcompensation of amphetamine-induced rotation in 6-hydroxydopamine-lesioned rats receiving transplants of fetal nigral neurons can be reduced by a lesion of the corticostriatal projection. Fetal ventral mesencephalic tissue was transplanted as a cell suspension into the dopamine-denervated striatum of unilaterally 6-hydroxydopamine-lesioned rats. Rats in which the transplants had produced a complete compensation or reversal of the lesion-induced rotational asymmetry in response to amphetamine (5 mg/kg, i.p.) were divided into two equal groups, sustaining either a knife-cut transection of prefrontal corticofugal efferents ipsilaterally to the grafts, or a sham-lesion. The animals were re-tested for amphetamine-induced rotation one week post-operatively, and were perfusion-fixed two hours after drug administration. Adjacent sections through the striatum were processed for Fos and tyrosine hydroxylase immunohistochemistry. At the amphetamine rotation test performed after cortical lesion surgery, the frontocortically deafferented animals exhibited a low rate of rotation in the direction ipsilateral to the dopaminergically denervated and grafted side, while sham-lesioned rats rotated towards the intact side. In sham-lesioned controls, the density of Fos-immunoreactive nuclei (no. of nuclei/mm2) was significantly higher in the reinnervated portion of the grafted striatum than on the contralateral side (+54 to 316%). In the frontocortically deafferented-grafted striata, Fos expression was not different from that measured on the contralateral side and significantly lower than in the sham-lesioned controls (-65-79%).(ABSTRACT TRUNCATED AT 250 WORDS)

Afferent Pathways↗
PubMed1989

Perception of rotated forms: a theory of information types.

The present article proposes a theory of form perception in an attempt to understand puzzling problems in mental rotation and in perception of forms rotated in the frontal-parallel plane. According to the theory, it is critical to distinguish four types of information. They result from the orthogonal combination of two binary distinctions: information can be orientation-free or orientation-bound, elementary or conjunctive. The theory provides an explanation as to when and why mental rotation has to be performed. If two forms can be discriminated only on the basis of conjunctive orientation-bound information, mental rotation or some other functionally equivalent strategy is required. Mental rotation is unnecessary if the forms differ in either type of orientation-free information, provided that the difference is actually encoded as such. This explanation along with the proposed distinctions among the four types of information was supported by two mental rotation experiments and three visual search experiments.

Female↗
PubMed1984

Evidence that apomorphine and pergolide induce rotation in rats by different actions on D1 and D2 receptor sites.

Apomorphine and the ergot derivative pergolide induced dose-dependent contralateral rotation in rats with unilateral 6-hydroxydopamine denervation of the ascending dopamine pathways. This was interpreted as an action on supersensitive receptors. However, large differences were found when comparing apomorphine and pergolide dose-response curves as well as the patterns of rotational behaviour the compounds elicited. Pergolide had a steep dose-response curve, while apomorphine had a flatter curve reaching a plateau at the dose of 1 mg/kg s.c. In doses higher than 1 mg/kg, apomorphine induced self-mutilation, while this was infrequent after pergolide. Apomorphine induced a two-peak pattern of rotation that never occurred when the same rats were tested with the ergot derivative. Both drugs induced dose-dependent ipsilateral rotation in animals with unilateral striatal kainic acid lesions but at doses 100 times higher. This effect was interpreted as an action on normosensitive receptors situated on the intact side. The differences between apomorphine and pergolide may be explained in terms of actions on different dopamine receptors, since the agonists were differently inhibited by neuroleptics acting on D1- or D2-type receptors. The D1/D2 antagonist cis-flupenthixol blocked both apomorphine and pergolide with similar potency, while sulpiride, a substituted benzamide devoid of any effect on D1 receptors, was a poor inhibitor of the apomorphine response. In contrast, sulpiride blocked pergolide rotation at doses 1000 times lower than those needed to block apomorphine rotation. Our results suggest the existence of functionally distinct sites related to the D1/D2 receptor classification.

Animals↗
PubMed1988

Rigidity of the nucleus during nuclear rotation in 3T3 cells.

Using near infrared microscopy and ultraviolet fluorescence microscopy of living 3T3 cells stained with the fluorochrome Hoechst 33342, we have demonstrated that the nucleoli and Hoechst 33342-stained chromocenters in the nucleus maintain a fixed pattern during nuclear rotation. We conclude that the term "nuclear rotation" refers to rotation of the entire nucleus in the cytoplasm of interphase cells, and that nuclear rotation is not an expression of karyoplasmic streaming. In conjunction with earlier results on nuclear rotation the data imply that the interface of nuclear rotation is located either between the two nuclear membranes or in the adjacent cytoplasm.

Benzimidazoles↗
PubMed1991

Apparatus to obtain rotational flexibility of the human knee under moment loads in vivo.

The contributions of this paper are twofold. One is the design and performance evaluation of new equipment to determine the rotational flexibility of the human knee in vivo. Since determining knee flexibility requires the application of external loads and the measurement of knee rotations, the new equipment consists of a load application stand and a triaxial goniometer. The triaxial goniometer noninvasively mounts to the leg and directly measures the relative three degrees-of-freedom rotations of the knee sequentially and independently. The goniometer incorporates several unique design features which enhance measurement accuracy. The load stand applies pure varus/valgus and external/internal axial moments either individually or in combination through the use of motors controlled by the test subject. Unique to this design are features which enable the application of moments to the knee which minimise shear forces. Other unique design features permit the stand to control hip and knee flexion angles, muscle contraction, and axial loading. To assess the accuracy with which rotations are measured during experiments, three tests were conducted with the equipment. One test evaluated the inherent accuracy of the goniometer, a second test assessed the potential for goniometer slippage during loading, and a third explored the effect of goniometer mounting on the repeatability of results. A special verification apparatus facilitated evaluation of goniometer inherent accuracy. A second contribution of the paper is an investigation of the effect of foot constraints (i.e. boundary conditions) on flexibility results. To make this investigation, three subjects were tested with the knee at 15 degrees of flexion. Results revealed large differences in flexibility between constraining the foot in both external/internal and varus/valgus rotations and permitting the foot to rotate freely in the direction not being loaded. Further, constraint moments as high as 23 Nm were also recorded. These results emphasise that in order to obtain accurate flexibility results for isolated loads, the foot must be unconstrained by the loading apparatus.

Biomechanical Phenomena↗
PubMed1984

Saturation transfer electron paramagnetic resonance of spin-labeled muscle fibers. Dependence of myosin head rotational motion on sarcomere length.

We have investigated the orientation and rotational mobility of spin-labeled myosin heads in muscle fibers as a function of the sarcomere length in the absence of ATP. An iodoacetamide spin label was used to label selectively two-thirds of the sulfhydryl-1 groups in glycerinated rabbit psoas muscle. Conventional electron paramagnetic resonance experiments were used to determine the orientation distribution of the probes relative to the fiber axis, and saturation transfer experiments were used to detect sub-millisecond rotational motion. When fibers are at sarcomere length 2.3 microns (full overlap), spin-labeled heads have a high degree of orientational order. The probes are in a single, narrow orientation distribution (full width 15 degrees), and they exhibit no detectable sub-millisecond rotational motion. When fibers are stretched (sarcomere length increased), either before or after labeling, disorder and microsecond mobility increase greatly, in proportion to the fraction of myosin heads that are no longer in the overlap zone between the thick and thin filaments. Saturation transfer difference spectra show that a fraction of myosin heads equal to the fraction outside the overlap zone have much more rotational mobility than those in fibers at full overlap, and almost as much as in synthetic myosin filaments. The most likely interpretation is that some of the probes, corresponding approximately to the fraction of heads in the overlap zone, remain oriented and immobile, while the rest are highly disordered (angular spread greater than 90 degrees) and mobile (microsecond rotational motion). Thus, it appears that myosin heads are rigidly immobilized by actin, but they rotate through large angles on the microsecond time-scale when detached from actin, even in the absence of ATP.

Animals↗
PubMed1993

A new device for blockout procedures in rotational path removable partial dentures.

The rationale of a rotation axis is discussed and on this basis a blockout device is designed for rotational path removable partial dentures. This device has three basic components, which are (1) the acrylic resin block, (2) the rotation axis, and (3) the functional part. In the blockout procedures for removable partial dentures with tilted mandibular molars, the rotation axis of the prosthesis is first localized by the blockout device. A knife edge, made of Duralay resin that corresponds to the survey lines of teeth to be used as supports, is constructed and is joined to the functional part of the blockout device. Blockout regions are determined by the rotational movement of the Duralay resin knife edge along the rotation axis of the blockout device. In addition to the function of blockout, the device can also be used to analyze diagnostic casts for critical undercuts. Internal and external types of blockout devices are also discussed.

Acrylic Resins↗
PubMed1990

Inhibition by enkephalin of medial vestibular nucleus neurons responding to horizontal pendular rotation.

Electrophysiological studies were performed to determine whether or not enkephalin modulates the activities of medial vestibular nucleus (MVN) neurons responding to horizontal pendular rotation using alpha-chloralose anesthetized cats. The effects of microiontophoretically applied drugs were examined in type I and type II neurons identified according to responses to horizontal, sinusoidal rotation; type I and type II neurons showed an increase and decrease in firing with rotation ipsilateral to the recording site and vice versa with contralateral rotation, respectively. Iontophoretic application of enkephalin suppressed spike firing induced by rotation of the animals in type I neuron, but not in type II neuron. The spike firing induced by iontophoretically applied glutamate was also inhibited during the application of enkephalin. The inhibition by enkephalin of both rotation- and glutamate-induced firing was antagonized by naloxone which was given simultaneously. These results suggest that enkephalin acts on MVN type I neuron to inhibit transmission from the vestibule, thereby controlling vestibulo-ocular reflex.

Animals↗
PubMed1982

Spontaneous and drug-induced rotation following localized 6-hydroxydopamine and kainic acid-induced lesions of the neostriatum.

Twelve groups of rats received small localized lesions produced by either 6-hydroxydopamine (6-OHDA) or kainic acid (KA) in one of six placements in the right neostriatum. All groups lesioned with 6-OHDA showed ipsilateral spontaneous and amphetamine-induced rotation and contralateral apomorphine-induced rotation. All groups lesioned with kainic acid showed ipsilateral spontaneous rotation on day 1 following the lesion but contralateral rotation by day 8, and no significant rotation to injections of either amphetamine or apomorphine. The histology suggested that the lesions were topographically specific, and it is therefore concluded that the neostriatum is topographically homogeneous in the mediation of rotational behaviour as measured in automated rotometers.

Animals↗
PubMed1996

Visually elicited head rotation in pigeons (Columba livia).

Horizontal rotational head movements were video-taped from pigeons standing freely in a rotating cylinder. The cylinder carried vertically striped patterns approximating a sinusoidally modulated horizontal intensity distribution. We altered systematically various stimulus parameters: spatial wavelength and contrast of the pattern, angular velocity of the pattern motion and mode of motion onset. We found: (1) both gradual acceleration of the patterned cylinder as well as immediate onset of pattern motion elicit the sequence of smooth following and saccadic resetting movement typical of the rotational "stare" head nystagmus; (2) in experiments with rapid onset of pattern motion, velocity of the smooth following response gradually increases to its steady-state level over a period of about 10 sec; (3) the saccadic head rotations are not stereotyped: larger and shorter saccades follow in an irregular sequence, saccadic velocity and average size varies with stimulus conditions; (4) in the range of 0.9-95 deg/sec, the velocity of the following phase increases in parallel with stimulus speed; (5) in the range of spatial wavelengths of the striped patterns from 6 to 45 deg, at a given drum velocity, patterns of short wavelengths elicit optokinetic head rotations with higher gain (head velocity/drum velocity) than patterns of long wavelengths; (6) response velocity increases with pattern contrast (Michaelson contrast 5, 32 and 75%), following approximately a logarithmic relation; (7) our results on rotational optokinetic head movements support the notion that the neural mechanism underlying motion detection operates like a correlation mechanism.

Animals↗
PubMed1981

Handling-induced seizures and rotational behavior in th Mongolian gerbil.

The aim of this report was to examine the relationship between sensory-induced seizures, cerebral laterality (as measured by rotation) and nigrostriatal asymmetry in Mongolian gerbils. Seizure resistant gerbils made proportionally more spontaneous turns to be preferred direction than sensitive animals. Three prototypical antiepileptic drugs strongly elicited rotational behavior (carbamazepine (10-20 mg/kg), diazepam (16 mg/kg) and pentobarbital (40 mg/kg)) and two others (phenobarbital 20-40 mg/kg) and ethosuximide (500 mg/kg)) also appeared to potentiate rotation; only diphenylhydantoin and trimethadione were effective. Two dopaminergic agonists, amphetamine (4 mg/kg) and apomorphine (16 mg/kg) enhanced rotation at anticonvulsant doses while the dopaminergic antagonist haloperidol reduced rotational behavior at a dose (1 mg/kg) which exacerbate seizure severity. Finally, surgical induction of nigrostriatal asymmetry by means of unilateral electrolytic striatal lesions reduced seizure severity; sham and bilateral striatal lesions had no significant effects on seizures. These results suggest that seizure activity and rotational behavior are inversely related and, furthermore, that the link between these two behaviors may be the asymmetry between nigrostriatal dopaminergic systems.

Amphetamine↗