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Query: UNIPROT:P50583 (asymmetrical)
 12,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Kinetics of inactivation of sodium channels in myelinated nerve from Rana pipiens were studied at 4.5 degrees C using the voltage clamp technique of Dodge & Frankenhaeuser (1958).2. Potassium currents were blocked by cutting the internodes in 20 mM-TEA-Cl + 100 mM-KCl and by adding 12 mM-TEA-Cl to the external Ringer. Leakage and capacitative currents were subtracted electronically.3. Kinetics of recovery from inactivation of the sodium channels were studied by inactivating the channels with a large depolarizing prepulse and allowing the channels to recover at different potentials; the extent of recovery was measured by applying a test pulse at various times after the prepulse.4. Kinetics of development of inactivation were studied by two different methods. The first was to measure the decay of sodium current under a maintained depolarization. The second method was to measure the decay of the peak sodium current in a test pulse as a function of time after the onset of a maintained depolarization. These two methods yielded similar results for the kinetics of inactivation development.5. Contrary to expectations of the Hodgkin-Huxley formalism, the time course of recovery from and development of inactivation is not strictly exponential. Rather, recovery from complete inactivation shows an initial delay which depends on recovery potentials. Development of inactivation at a fixed potential exhibits at least two exponentials.6. The steady-state inactivation curve h(infinity)(E) is asymmetrical and is fitted better by 1/[1+exp (A(1)E+B(1)) +exp (A(2)E+B(2))] than by 1/[1+exp (AE+B)].7. Most of the above kinetic observation on inactivation can be fitted by the following modification of the h system of the Hodgkin-Huxley formalism: [Formula: see text]8. In the analysis it was not necessary to modify the concept of two separate processes, activation and inactivation, governing the opening and closing of the sodium channels.
J Physiol 1977 Dec
PMID:Inactivation of sodium channels: second order kinetics in myelinated nerve. 30 88

Sixty-six consecutive patients without left ventricular volume overload, significant arrhythmia or significant pericardial effusion were examined by M-mode echocardiography immediately before diagnostic left- and right-heart catheterization. Using various echocardiographic measurements, left ventricular stroke volume (SV) was calculated according to eight different echocardiographic formulas (SVE) that have been proposed previously. At catheterization SV was also determined by thermodilution (SVT) and by single-plane left ventricular cineangiography in the right anterior oblique projection (SVA). When comparing SVE with SVT, the four formulas developed to calculate mitral or aortic flow failed (r = 0.10 to 0.54). As expected, poor correlations (r = 0.22 to 0.47) were also found when formulas used to calculate ventricular volumes from the ventricular diameter or SV from the change in diameter (left ventricular formulas) were used in coronary patients with grossly asymmetrical ventricular contraction patterns. When the use of the left ventricular formulas was confined to patients with symmetrical or almost symmetrical contraction, two formulas yielded favorable correlations of r = 0.84, SEE = 12.7 ml and r = 0.86, SEE = 12.2 ml, respectively. These correlations were comparable to the correlation between our two invasive reference techniques (r = 0.81; SEE = 12.2 ml). The comparison between SVE and SVA confirmed the results of the thermodilution study, though the correlations were generally weaker. We conclude that the formula of Teichholz et al., which was the best of all tested formulas, may be used to obtain a clinically useful estimate of SV in patients in whom symmetrical or almost symmetrical left ventricular contraction can be anticipated.
Circulation 1979 Dec
PMID:Comparative value of eight M-mode echocardiographic formulas for determining left ventricular stroke volume. A correlative study with thermodilution and left ventricular single-plane cineangiography. 49 56

It is classically considered that cochlear fatigue and acoustic trauma occur when intensity is such that the ear is saturated, i.e. when the microphonic potential fails to increase in a linear fashion in relation to intensity and when distorsion appears. The present report concerns a study in the guinea pig of the relationship between the non-linearity of microphonic responses, and their fatigability. The results show that fatigability is related not only to non-linearity but also to the asymmetry of responses. The asymmetry of microphonic responses may be interpreted as reflecting an asymmetrical ionic flow at the upper pole of hair cells, resulting in an accumulation of potassium ions within and around hair cells and thereby creating a depression of responses.
Ann Otolaryngol Chir Cervicofac 1979 Dec
PMID:[Relationship between cochlear fatigue and the asymmetrical non-linearity of microphonic responses in the guinea pig (author's transl)]. 53 88

Synaptic junctions located on the dendrites of lamprey (Petromyzon marinus) reticulospinal neurons labelled with intracellularly-injected horseradish peroxidase were studied. The normal ultrastructure of the synaptic junctions was defined and several quantitative measures made from each junction in order to test the hypothesis that distally-located synapses are ultrastructurally different from those located at proximal dendritic sites. A total of 820 contacts from one neuron and 279 from a second neuron ranging from 20 to 340 microns from the soma were quantified. The vast majority of the presynaptic endings contained round, clear-cored vesicles and formed an asymmetrical membrane differentiation with the postsynaptic dendrite. A small fraction of the population contained flattened or pleomorphic vesicles and these synapses were equally distributed with respect to distance from the soma. Many of the terminals contained a few large dark- and clear-cored vesicles. Four quantitative measures of each synaptic contact were made. These included vesicle number, length of differentiated membrane, vesicle area and terminal area. Four ratios relating the different quantitative measures were also calculated. Each ratio or measurement from the synaptic junctions was plotted as a function of distance from the soma to determine if differences existed at any distance. It was found that synaptic junctions are uniformly similar and that distal junctions did not differ significantly (P greater than 0.05) from those at proximal dendritic sites. It is concluded that if distal synapses do compensate for their remote location they do this is some other way, possibly by increasing the number of synaptic contacts made by each presynaptic axon.
J Neurocytol 1979 Dec
PMID:The relationship between some measures of synaptic ultrastructure as a function of distance from the soma on lamprey reticulospinal neurons. 54 91

The development of rat transitional epithelial cells grown on conventional non-permeable surfaces was compared with development on permeable collagen supports. On glass or plastic surfaces, cells grew as expanding nomolayer sheets. Once confluent, growth continued with a bilayer being formed in most areas and apical cells being continuously sloughed off. Although most cells were interconnected by desmosomes, and junctional complexes were formed, no other indications of differentiation were observed. After 2-3 wk of growth, division stopped and cel death ensued. In contrast, single-cell suspensions plated on collagen-coated nylon disks reassociated into multicellular islands and commenced growth. Mitoses were confined to the basal cells in contact with the permeable substrate. The islands developed into epithelial trilayers, tapering to monolayers along spreading edges. Once the islands were confluent, stratification was completed and appeared similar to that observed in vivo. Germinal cells formed a basal lamina, and the upper layer was composed of large, flattened cells with an unusually thick asymmetrical plasma membrane on the apical surface. Electron microscopic and radioactive tracers demonstrated "leaky" zonulae occludentes with a restricted permeability to small molecules. The movement of urea was retarded in comparison to water. Unlike the slow turnover of adult epithelium in vivo, maturation and sloughing of apical cells were measurable. Transfer of cells could be effected and growth maintained for up to 4 mo. These results may indicate the necessity of a nutrient-permeable growth surface for the polarized differentiation of adult transitional epithelium.
J Cell Biol 1979 Dec
PMID:The growth and differentiation of transitional epithelium in vitro. 57 72

Extraocular muscle enlargement was symmetrical in 70% and asymmetrical in 30% of patients with Graves' ophthalmopathy. True unilateral muscle involvement occurred in 6%. Computed tomography (CT) showed bilateral orbital involvement in 50% of patients presenting clinically with unilateral eye signs. In patients without a clinically apparent ophthalmopathy, CT demonstrated muscle enlargement in 40%. The medial and inferior rectus muscles were the most frequently and most severely involved. Orbital radiation therapy can result in a decrease in size of involved muscles.
J Comput Assist Tomogr 1979 Dec
PMID:Appearance of Graves' disease on orbital computed tomography. 58 52

A 58-year-old man was admitted with a progressive, subacute asymmetrical paraparesis. The patient denied a previous syphilitic infection, but spinal fluid examination disclosed a lymphocytic pleocytosis, hypoglycorrhachia, and a positive serologic test for syphills. Clinical improvement resulted from a 14-day course of penicillin. Syphilitic involvement of the nervous system appears to be increasing in the United States and should be included in the differential diagnosis of progressive paraparesis.
Arch Neurol 1977 Dec
PMID:Syphilitic meningomyelitis. A case report. 58 2

On stereoscopic examination of the lumbar spines of 6 patients with rheumatoid arthritis and spinal disease we found typical rheumatoid erosions in the apophyseal joints. 2 also had severe asymmetrical disc destruction with associated involvement of the vertebral bodies and scoliosis. In one of these patients who developed Staphyloccocus aureus septicaemia, infection was localized in this part of the lumbar spine.
Ann Rheum Dis 1977 Dec
PMID:Rheumatoid involvement of the lumbar spine. 59 45

Two experimental approaches examined observers' ability to characterize shape symmetry based upon the information obtained within a single fixation. Exp. I tested observers' ability to discriminate among three levels of symmetry on the basis of a 25-msec. presentation. Results indicated that identification accuracy was higher for symmetrical and asymmetrical shapes than for mixed shapes, which contained both symmetrical and asymmetrical components. Exp. II tested observers' ability to detect a given level of symmetry by means of a signal-detection approach. Symmetrical shapes were detected better than asymmetrical shapes. Detectability of mixed shapes was lower than that for both symmetrical and asymmetrical shapes. The results of Exps. I and II demonstrate that observers can characterize shape symmetry on the basis of information available within a single fixation. The data are supportive of the hypothesis that a global response to the over-all configuration of the shape serves to facilitate form perception.
Percept Mot Skills 1977 Dec
PMID:Global detection of symmetry. 60 12

Spontaneous levels of structural chromosomal aberrations in human peripheral lymphocytes were studied cytogenetically in 49 female and 56 male subjects. With a total of 16 267 metaphase spreads examined, 191 cells were found to contain chromosomal aberrations, giving a rate of 1.17%. The rates of individual aberration types were as follows: chromatid fragments, 0.39%; chromosome fragments, 0.71% dicentrics, 0.06%; symmetrical and asymmetrical chromatid exchanges, 0.01%; and rings, 0.006%. There were significant differences in aberration yields between females aged 20--29 yr. and 60--70 yr., whereas males aged 20--50 yr. showed no difference. The two sexes differed significantly in chromatid fragments, chromosome fragments and aberrants cells.
Mutat Res 1978 Dec
PMID:Spontaneous chromosomal aberration levels in human peripheral lymphocytes. 72 12


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