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At least 19 recordsLinked to original sources
PubMed1978

Nocturnal rotation in normal rats: correlation with amphetamine-induced rotation and effects of nigrostriatal lesions.

Normal unoperated rats were observed to rotate (turn in circles) at night. For most (91.7%) rats, the preferred direction of rotation was consistent across hours and days and was the same as the direction of rotation elicited by D-amphetamine (1.0 mg/kg) during the day. The magnitudes of nocturnal and D-amphetamine-induced rotation were also highly correlated. After rats showed stable diurnal patterns of rotation, unilateral lesions were made in either the substantia nigra, the nigrostriatal bundle or the caudate nucleus. All lesions produced transient contralateral rotation within the first 24-48 h after surgery. The time-course of this contralateral rotation was more prolonged after nigral lesions than after nigrostriatal bundle lesions and least after caudate lesions, suggesting that the duration of a degeneration release of dopamine is proportional to the length of the degenerating axon. Lesion size was correlated with the intensity of contralateral rotation but not with the time-course. At each rostralcaudal level, the magnitude of contralateral rotation was greater if the lesion was in the side of the brain opposite to the preoperative direction of rotation than if in the same side. By three days after surgery, all rats returned to a mostly normal diurnal cycle with the direction of rotation now being ipsilateral to the lesion. D-Amphetamine potentiated the ipsilateral rotation, though rats with lesions in the same side of the brain as the preoperative direction of rotation had larger drug responses than rats with similar lesions in the opposite side of the brain. By one month after surgery, the direction of spontaneous rotation of most rats had returned to the preoperative direction. As at all other times, the magnitude of rotation was, in part, dependent on the side of the lesion with respect to the preoperative bias. It is suggested that, following a unilateral lesion, compensatory processes occur to a greater extent if the lesion is in the normally more active side of the brain.

Animals↗
PubMed1976

Mental rotation by the blind: does mental rotation depend on visual imagery?

Congentially blind adventitiously blind, and blindfolded sighted adults made same-different judgments of pairs of tactile forms. Two forms were presented in the same orientation, or one form differed from the other by a clockwise rotation of 30 degrees, 60 degrees, 120 degrees, or 150 degrees. Like the reaction times for the sighted and the adventitiously blind, reaction times for the congenitally blind increased as a linear function of angular discrepancy between stimuli, suggesting that the congentially blind, like the sighted and adventitiously blind, mentally rotated one form into congruence with the other to make judging easier. Corroboration of the mental rotation inference came from subjects' introspective reports. Inasmuch as the congenitally blind presumably do not have the ability to visually represent form, the present results suggest that mental rotation does not depend upon visual imagery. Thus, with respect to current speculation as to whether visual imagery is a necessary component of mental rotation, the present findings suggest that it is not.

Adolescent↗
PubMed1977

Maxillary rotation during human growth: annual variation and correlations with mandibular rotation. A metal implant study.

For a longitudinal study of the maxillary rotation, based on lateral headplates, a material of 22 patients with metallic implants in both jaws has been used. It has been established that the degree of maxillary rotation shows variations in direction and in intensity each year. It is smaller, in absolute value, than the degree of mandibular rotation. Due to the fact the direction of the maxillary and mandibular rotations are not always the same, it appears that the interaction between the maxillary and mandibular rotations plays an important role in the vertical and sagittal relationships of both jaws.

Adolescent↗
PubMed1977

Induction of illusory self-rotation and nystagmus by a rotating sound-field.

Subjects seated in darkness often experience illusory self-rotation when exposed to a rotating sound field. Compelling illusions of self-rotation are generally accompanied by nystagmoid movements of the eyes with the slow phase in the direction opposite that of the experienced self-rotation. These phenomena are related to the functioning of a spatial constancy mechanism by which a stable distinction is normally maintained between movements of self and movements of the environment. The appearance of nystagmus during illusory self-rotation indicates that apparent body orientation can influence oculomotor control.

Acoustic Stimulation↗
PubMed1976

A spectroscopic technique for measuring slow rotational diffusion of macromolecules. 2: Determination of rotational correlation times of proteins in solution.

Experiments have been performed to test the validity of measurements of slow rotational diffusion using eosin isothiocyanate as a probe. When eosin-protein conjugates are covalently bound to Sepharose 4B, the dichroism of the flash-induced absorption transient does not decay with time. The magnitude of the dichroism is smaller than for eosin in solid solution. These results, together with measurements with highly viscous solutions, demonstrate the existence of a rapid but restricted independent motion of the eosin probe. This causes a partial loss of pf dochroism leaving a residual dichroism whose time dependence is determined by the rotational motion of the protein. Rotational correlation times in the microsecond-millisecond time range have been determined for eosinprotein conjugates dissolved in glycerol-water mixtures of varying viscosity. The measured values are in good agreement with theoretical predictions and show the correct dependence on the viscosity of the medium and the size and state of association of the protein.

Animals↗
PubMed1978

The repair of chronic massive ruptures of the rotator cuff of the shoulder by use of a freeze-dried rotator cuff.

In sixteen patients with massive tears of the rotator cuff of the shoulder, bridging of the defect with a freeze-dried graft of a rotator cuff from a cadaver produced a satisfactory repair in all cases. A good or excellent functional result was obtained in all but two patients, with a definite decrease or absence of nocturnal pain in all sixteen. The operative technique includes avoidance of a complete acromionectomy and an adequate suture of the deltoid muscle to the acromion after an acromioplasty.

Acromioclavicular Joint↗
PubMed1977

Ultrastructural changes in intersegmental cuticle during rotation of the terminal abdominal segments in a mosquito.

The terminal abdominal segments of male Aedes aegypti rotate 180 degrees within 24 hr after adult emergence, rotation occurring in the intersegmental membrane between abdominal segments VII and VIII. The ultrastructure of this rotating membrane is compared with non-rotating intersegmental membranes at different developmental stages. The deposition of cuticle in both the rotating and non-rotating intersegments appears ultrastructurally similar, and follows the sequential pattern described for the insects. Shortly after adult emergence, however, disruptive changes occur in the membrane cuticle that are more pronounced in non-rotating intersegments. This disruption occurs initially 1 hr after adult emergence and becomes maximal within 3 hr. Disruption appears to occur by the addition of fluid to the cuticle and results in a ten-fold increase in cuticle thickness in non-rotating intersegments but only a two-fold increase in thickness in the rotating intersement. While in the disrupted condition, the non-rotating intersegmental membranes become extensively folded whereas the cuticle in the rotating intersegment becomes stretched. During rotation, strain forces in the rotating intersegment result in a reorientation of microfibers in the cuticle from parabolic to parallel. This reorientation is presumably brought about by plastic flow.

Abdomen↗
PubMed1975

Rotation of spin-cast hydrogel lenses.

This study was designed to determine if spin-cast hydrogel contact lenses rotate on the eye, and if so, to investigate the parameters which influence rotation. If these lenses do rotate, correction of residual astigmatism may be difficult, if not impossible. We monitored the lens rotation associated with 12 specially marked B and L Soflens TM contact lenses on six corneas after insertion and 30 minutes later by use of high speed motion pictures. To analyze lens rotation, the film was projected with a stop action projector and the amount of rotation measured with a protractor. Thirty-one percent of the 144 observations made showed some lens rotation, the majority of which was encyclorotation. Most of the lenses showed little or no change in rotation between the two time periods. Corneal curvature was the only lens or eye parameter associated with rotation. Why lenses were more likely to rotate on steeper corneas is not fully understood. Our findings indicate that Softlenses TM may rotate, but there is no definite way of determining in advance if a given lens will rotate on a given eye. This emphasizes the need for individualized lens fitting and proper patient monitoring.

Adult↗
PubMed1979

Differential polarized phase fluorometric investigations of diphenylhexatriene in lipid bilayers. Quantitation of hindered depolarizing rotations.

Differential polarized phase fluorometry has been used to investigate the depolarizing rotations of 1,6-diphenyl-1,3,5-hexatriene (DPH) in isotropic solvents and in lipid bilayers. For DPH dissolved in isotropic solvents, there is a precise agreement between the observed and predicted values for maximum differential tangents, indicating that in these media DPH is a free isotropic rotator. In lipid bilayers the tangent defects (i.e., the differences between the calculated and the observed maximum differential tangents) are too large to be explained by anisotropy in the depolarizing rotations but are accounted for by hindered isotropic torsional motions for the fluorophore [Weber, G (1978) Acta Phys. Pol A 54, 173]. This theory describes the depolarizing rotations of the fluorophore by its rotational rate R (in radians/second) and the limiting fluorescence anisotropy (r) at times long compared with the fluorescence lifetime. Through the combined use of both steady-state anisotropy measurements and differential phase measurements, we have demonstrated that one may obtain unique solutions for both R and r. For DPH embedded in vesicles prepared from dimyristoyl-, dipalmitoyl-, and distearoylphosphatidylcholines, the depolarizing motions are highly hindered at temperatures below the transition temperature (Tc) but are unhindered above Tc. The apparent rotational rates of the probe do not change significantly at Tc. These data suggest that the changes observed in the steady-state anisotropy near Tc derive primarily from changes in the degree to which the probe's rotations are hindered, and only to a small extent from changes in rotational rate. For DPH embedded in bilayers that contained 25 mol % cholesterol, no clear transition occurred and the rotations appeared to be hindered at all temperatures. The rotational motions of DPH embedded in dioleolyphosphatidylcholine were found to be far less hindered, but the rotational rates were similar to those obtained in the saturated phosphatidylcholines. Finally, the data show that in an anisotropic environment, such as that of a lipid bilayer, steady-state fluorescence anisotropy measurements alone cannot yield quantitatively meaningful rotational rates. Extrapolation of steady-state aniosotropy data to the quantitation of membrane viscosity is therefore difficult, if not invalid; however, qualitative comparisons can be useful.

Fluorescence Polarization↗
PubMed1977

Effect of rotation on radiographic dimensions of the humerus and femur.

Ten humeri and ten femora were radiographed in nine positions of longitudinal rotation. In each position total, medullary and cortical widths of the diaphyses (TW, MW, CW) were measured to assess the effect of rotation on these dimensions. The results were expressed as differences from the values in the neutral position (delta TW, delta MW, delta CW). In the humerus, medial rotation produced greater changes than lateral rotation. Though rotation in either direction increased CW, the systematic error due to medial rotation to only 5 degrees (approximately +0.0058 cm per degree) was more than double that due to lateral rotation. In the femur, lateral rotation had the greater effect, producing a marked decrease in CW (approximately -0.0072 cm per degree). Medial rotation produced only a slight increase in CW. The ratios CW/TW ("cortical index") and CA/TA ("area ratio") were calculated and expressed as differences from the values in the neutral position (delta CW/TW, delta CA/TA). Rotation affected these variables much less than the linear dimensions. Furthermore, through the variance of delta TW, delta MW and delta CA/TA increased only slightly or not at all. These results suggest that if radiographic morphometry is to be applied to the humerus and femur, these ratios rather than transverse dimensions should be used. Sequential changes in CW may be totally obscured by small rotational errors.

Anthropometry↗