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At least 19 recordsLinked to original sources
PubMed1978

Studies on the orientations of the mitochondrial redox carriers. II. Orientation of the mitochondrial chromophores with respect to the plane of the membrane in hydrated, oriented mitochondrial multilayers.

Orientations of the active site chromophores of the mitochondrial redox carriers have been investigated in hydrated, oriented multilayers of mitochondrial membranes using optical and EPR spectroscopy. The hemes of cytochrome c oxidase, cytochrome c1, and cytochromes b were found to be oriented in a similar manner, with the normal to their heme planes lying approximately in the plane of the mitochondrial membrane. The heme of cytochrome c was either less oriented in general or was oriented at an angle closer to the plane of the mitochondrial membrane than were the hemes of the "tightly bound" mitochondrial cytochromes. EPR spectra of the azide, sulfide and formate complexes of cytochrome c oxidase in mitochondria in situ obtained as a function of the orientation of the applied magnetic field relative to the planes of the membrane multilayers showed that both hemes of the oxidase were oriented in such a way that the angle between the heme normal and the membrane normal was approx. 90 degrees.

Animals↗
PubMed1979

Studies of the orientation of the mitochondrial redox carriers. III. Orientation of the gx and gy axes of the hemes of cytochrome oxidase with respect to the plane of the membrane in oriented membrane multilayers.

The EPR absorption properties of the hemes of cytochrome oxidase and their liganded derivatives were examined in oriented multilayers from isolated oxidase, mitochondrial membranes and membrane fragments of a bacterium, Paracoccus denitrificans. The hemes of the oxidase in all the systems investigated were oriented normal to the plane of the multilayers. The directions of the g signals corresponding to the gx and gy axes of the g tensor were found to be different in low-spin ferric heme in fully oxidized oxidase and in half-reduced liganded oxidase. It is suggested that this different orientation of gx and gy in fully oxidized oxidase and half-reduced liganded oxidase arises because the respective EPR signals belong to two different hemes, those of cytochrome a and a3.

Animals↗
PubMed1992

Orientational distribution of spin-labeled actin oriented by flow.

Previous studies on spin-labeled F-actin (MSL-actin), using saturation transfer electron paramagnetic resonance (ST-EPR), have demonstrated that actin has submillisecond rotational flexibility and that this flexibility is affected by the binding of myosin and its subfragments. This rotational flexibility does not change during the active interaction of myosin heads, actin, and adenosine triphosphate. However, these ST-EPR studies, performed on randomly oriented actin, would not be sensitive to orientational changes on the millisecond time scale or slower. In the present study, we have clarified these results by performing conventional EPR experiments on MSL-actin oriented by flow to detect changes in the orientational distribution. We have determined the orientational distribution of the spin labels relative to the magnetic field (flow direction) by comparing experimental EPR spectra to simulated EPR spectra corresponding to known orientational distributions. Spectra acquired during flow indicate two populations of probes: a highly ordered population and a disordered population. For the ordered population (28% of the total spin concentration), the angle between the actin filament axis and the nitroxide z axis (theta) fits a Gaussian distribution centered at 32.0 +/- 0.9 degrees, with a full width at half maximum of 20.7 +/- 3.9 degrees. The angle between the nitroxide x axis and the projection of the field in the xy plane (phi) is centered at 37.5 +/- 9.2 degrees with a full width of 24.9 +/- 10.7 degrees. This orientational distribution is not significantly changed upon the binding of phalloidin or myosin subfragment 1 (S1), indicating that these proteins do not affect the axial orientation of actin subunits. Spectra of spin-labeled S1 (MSL-S1) bound to actin oriented by flow have about the same orientational distribution as MSL-S1 bound to actin in oriented fibers. Thus, the oriented fraction of flow-oriented actin filaments has nearly the same high degree of alignment as the actin filaments in muscle fibers.

Actins↗
PubMed1975

The orientation anisotropy and orientation constancy: a visual evoked potential study.

Two experiments were conducted on the orientation anisotropy in which averaged visual evoked potentials (VEPs) were recorded from the occipital scalp. The first experiment confirmed the findings of Maffei and Campbell (1970) that obliquely oriented gratings alternated back and forth produced smaller-amplitude VEPs than when the gratings were oriented horizontally or vertically. Since no asymmetry was found in VEPs produced by a Julesz figure presented under identical conditions, it was concluded that direction of displacement could not have been contributing to the effect. In a second experiment head tilt of the subject was manipulated together with grating orientation and the results indicated that the orientation anisotropy is retinally rather than gravitationally referenced. It was concluded that the site of orientation constancy is located either at higher levels of the primary visual system or in the second visual system.

Adult↗
PubMed1975

The effects of lesions of the superior colliculus on locomotor orientation and the orienting reflex in the rat.

The effects of bilateral removal of the superior colliculus or visual cortex on visually guided locomotor movements in rats performing a brightness discrimination task were investigated directly with the use of cine film. Rats with collicular lesions showed patterns of locomotion comparable to or more efficient than those of normal animals when approaching one of 5 small doors located at one end of a large open area. In contrast, animals with large but incomplete lesions of visual cortex were distinctly impaired in their visual control of approach responses to the same stimuli. On the other hand, rats with collicular damage showed no orienting reflex or evidence of distraction in the same task when novel visual or auditory stimuli were presented. However, both normal and visual-decorticate rats showed various components of the orienting reflex and disturbance in task performance when the same novel stimuli were presented. These results suggest that although the superior colliculus does not appear to be essential to the visual control of locomotor orientation, this midbrain structure might participate in the mediation of shifts in visual fixation and attention. Visual cortex, while contributing to visuospatial guidance of locomotor movements, might not play a significant role in the control and integration of the orienting reflex.

Acoustic Stimulation↗
PubMed1979

The orientational freedom of molecular probes. The orientation factor in intramolecular energy transfer.

The measurement of the efficiency of Förster long-range resonance energy transfer between donor (D) and acceptor (A) luminophores attached to the same macromolecular substrate can be used to estimate the D-A separation, R. If the D and A transition dipoles sample all orientations with respect to the substrate (the isotropic condition) in a time short compared with the transfer time (the dynamic averaging condition), the average orientation factor less than K2 greater than is 2/3. If the isotropic condition is not satisfied but the dynamic averaging condition is, upper and lower bounds for less than K2 greater than, and thus R, may be obtained from observed D and A depolarizations, and these limits may be further narrowed if the transfer depolarization is also known. This paper offers experimental protocols for obtaining this reorientational information and presents contour plots of less than K2 greater than min and less than K2 greater than max as functions of generally observable depolarizations. This permits an uncertainty to be assigned to the determined value of R. The details of the D and A reoreintational process need not be known, but the orientational distributions are assumed to have at least approximate axial symmetry with respect to a stationary substrate. Average depolarization factors are derived for various orientational distribution functions that demonstrate the effects of various mechanisms for reorientation of the luminophores. It is shown that in general the static averaging regime does not lend itself to determinations of R.

Energy Transfer↗
PubMed1978

[Orientation of the cleavage spindles in pulmonate mollusks. I. The role of the form of the blastomeres in 2d cleavage spindle orientation].

In the normal two-celled embryos of various pulmonate molluscs, the orientation of spindles characteristic of metaanaphase is being frequently established gradually, in the process of transition from pro- to metaphase accompained by the growth of spindle and asters. The typical growth of contact zone between the blastomeres of the common pond snail embryos was inhibited to a different extent under their cultivation after the 1 cleavage division in the calcium-free media or after trypsinization. At the same time the orientation of meta-anaphase spindles was markedly affected (as judged by an angle alpha between the spindle axis and the plane of contact zone in the equatorial projection). When analyzing the model distributions of the angles between the two spindle axes (in the same projection), it was shown that the empirical distributions of these angles corresponded to the principle of stochastic combination of two alpha. A conclusion is drawn that the orientation of one spindle does not depend on that of another but the position of each of them depends on the size of the contact zone and, hence, on the general form of the adjacent blastomere region. Some other processes determining the spindle orientation are discussed.

Anaphase↗
PubMed1978

[Orientation of the cleavage spindles in pulmonate mollusks. II. The role of the architecture of the intercellular contacts in III and IV cleavage spindle orientation].

In the normal development of pulmonate molluscs, the variety of orientations of the III and IV cleavage spindles markedly reduces in the process of transition from pro- to meta- and anaphase. Even prior to the completion of spindle growth in these cleavage divisions the external faces of blastomeres become asymmetrical due to intercellular interactions but the whole system of external intercellular contacts (edges) is characterized by a certain symmetry. This symmetry coincides partially or fully with that of the system of definitive spindles. In the artificially obtained four-celled common pond snail embryos with the chain-like position of blastomeres, the III cleavage spindles were oriented at right angles to the polar axis, rather than in parallel with it (as in the normal development). The eight-celled embryos with symmetrical external faces of macromeres were also obtained. The variety of orientation of the IV cleavage definitive spindles in such embryos was markedly widened and in the macromeres with inverse asymmetry the inversion of the sign of declination of the spindles was observed. The spindle orientation depends, thus, on the form of adjacent region of the external face. This form as a whole is determined by the mutual position of blastomeres, curvature of surface and relative length of the face edges.

Anaphase↗
PubMed1976

The differential impact of work-oriented vs. communication-oriented juvenile correction programs upon recidivism rates in delinquent males.

This study examined recidivism rates in work-oriented (N = 30) and communication-oriented (N = 30) juvenile delinquency programs for males. Both groups were matched for age, ethnic origin, educational achievement, and reading scores. Chi-square analyses indicated significant differences in recidivism rates between groups in both residential (chi2 - 6.71, df = 1, p less than .01) and aftercare (chi2 = 3.89, df = 1, p less than .05) programs. In each phase of the treatment program, recidivism was highest in the work-oriented group. The results suggested that (a) facilitation of family interaction and communication is related closely to successful treatment of the delinquent and consequent recidivism; (b) group counseling that provides the youth and parents an opportunity to learn better communication skills appears to improve family cohesion and solidarity; and (c) newer therapeutic approaches in delinquency should concentrate on filial and family-type therapies.

Adolescent↗
PubMed1978

Studies on the orientations of the mitochondrial redox carriers. I. Orientation of the hemes of cytochrome c oxidase with respect to the plane of a cytochrome oxidase-lipid model membrane.

The liganded derivatives of mitochondrial cytochrome c oxidase have been prepared in hydrated oriented multilayers of membranous cytochrome c oxidase. The optical spectra of the liganded derivatives recorded at an angle of 45 degrees between the incident light beam and the normal to the planes of the membranes in the multilayers show dichroic ratios of almost 2 in the visible region and 1.2-1.4 in the Soret region. The dichroic ratios were found to be similar for both cytochromes a and a3. Electron paramagnetic resonance spectra of the azide, sulfide, and formate complexes of cytochrome c oxidase obtained as a function of the orientation of the applied magnetic field relative to the planes of the membranes in the multilayer confirm the optical data and demonstrate that both hemes of cytochrome c oxidase are oriented such that the angle between the heme normal and the membrane normal is approximately 90 degrees.

Animals↗
PubMedDate not supplied

Object-orientated DBMS techniques for time-oriented medical record.

In implementing time-orientated medical record (TOMR) management systems, use of a relational model played a big role. Many applications have been developed to extend query and data manipulation languages to temporal aspects of information. Our experience in developing TOMR revealed some deficiencies inside the relational model, such as: (a) abstract data type definition; (b) unified view of data, at a programming level; (c) management of temporal data; (d) management of signals and images. We identified some first topics to face by an object-orientated approach to database design. This paper describes the first steps in designing and implementing a TOMR by an object-orientated DBMS.

Algorithms↗
PubMed1975

[Orientation without external orientation clues in reptiles (Hemidactylus frenatus Gekkonidae)].

In a black-painted cylindric arena Geckos (Hemidactylus frenatus) are able to find their hiding place without the aid of external orientation clues. This proprioceptive knowledge of the position is independent of the azimuth of the actual position of head and body, but it is influenced by a passive turning of the reptile. These findings lead to the assumption that the receptors of the labyrinth participate in the endogeneous (idiothetic) course control.

Animals↗
PubMed1979

The influence of verbal descriptions versus orientation codes on kindergartners' memory for the orientation of pictures.

Kindergarten children who viewed a series of 10 line drawings of objects subsequently showed little ability to distinguish between these pictures and their left-right mirror images. However, the children's memory for orientation improved substantially when children were induced to (a) give detailed verbal descriptions of the pictures, or (b) specify a difference between characteristics on the child's side versus the experimenter's side of each picture, or (c) both. The 3 induced strategies were equally effective. On a posttest given approximately a week later, the children did not maintain use of any of these effective strategies.

Attention↗
PubMed1976

Schneider-oriented versus Conrad-oriented psychiatric diagnosis in the same German clinic.

The Chair of the University Nervenklinik in Homburg/Saar was held by Klaus Conrad from 1949-58 and by H.-H. Meyer, a former pupil and colleague of Kurt Schneider, from 1962-72. As the catchment area and admission policy of the clinic remained substantially unchanged throughout, comparison of the relative proportions of all admissions allocated to different diagnostic categories in 1949-58 and 1962-72 can be used to elucidate the similarities and differences between Conrad's and Schneider's diagnostic criteria. The results of this comparison indicate that Schneider's concept of schizophrenia was broader than Conrad's, and his concept of manic-depressive depression more restricted. More detailed comparisons are complicated by differences in nomenclature and in the varieties of functional mental illness recognized in the two periods. However, it seems that Conrad's concept of mania was wider only when the atypical schizophrenia-like psychoses diagnosed during the Conrad era were added to the Conrad-oriented cases of mania; when this was not done, the Schneiderian concept of mania was broader.

Adjustment Disorders↗
PubMed1976

[Functional hemispheric asymmetries in perception of digit and line orientation orientation (author's transl)].

In Exp. I, right-handed Ss made the "same" or "diffeeent" judgement to paired digits serially presented to the right and left visual field, and exhibited erroneous judgements in the left visual field lead condition. These results suggest the left hemisphere superiority. In Exp. II, the Ss were requested to make the "same" or "different" judgment and to press a key as fast as possible to the paired line orientation. The right visual field lead condition product more errors than the left visual field lead condition. This suggests the right hemisphere superiority. But no difference appeared between both conditions in the reaction time. The opposite hemispheric superiority, found in perceiving verbal and non-verbal materials in the 2 experiments, would be attributed to the basic difference in "perceptual" process.

Dominance, Cerebral↗