scholarly journals The development of handedness in left/right asymmetry

Development ◽  
1990 ◽  
Vol 109 (1) ◽  
pp. 1-9 ◽  
Author(s):  
N.A. Brown ◽  
L. Wolpert
Keyword(s):  
Reaction Diffusion ◽  
Specific Model ◽  
Cellular Level ◽  
Abnormal Development ◽  
Loss Of Function ◽  
Specific Interpretation ◽  
Interpretation Process ◽  
Left And Right ◽  
The Difference ◽  
Left Right Asymmetry

The development of handed asymmetry requires a special mechanism for consistently specifying a difference between left and right sides. This is to be distinguished from both random asymmetry, and from those left/right differences that are mirror symmetrical. We propose a model for the development of handedness in bilateral animals, comprising three components. (i) A process termed conversion, in which a molecular handedness is converted into handedness at the cellular level. A specific model for this process is put forward, based on cell polarity and transport of cellular constituents by a handed molecule. (ii) A mechanism for random generation of asymmetry, which could involve a reaction-diffusion process, so that the concentration of a molecule is higher on one side than the other. The handedness generated by conversion could consistently bias this mechanism to one side. (iii) A tissue-specific interpretation process which responds to the difference between the two sides, and results in the development of different structures on the left and right. There could be direct genetic control of the direction of handedness in this model, most probably through the conversion process. Experimental evidence for the model is considered, particularly the iv mutation in the mouse, which appears to result in loss-of-function in biasing, and so asymmetry is random. The model can explain the abnormal development of handedness observed in bisected embryos of some mammalian, amphibian and sub-vertebrate species. Spiral asymmetry, as seen in spiral cleavage and in ciliates, involves only conversion of molecular asymmetry to the cellular and multicellular level, with no separate interpretation step.

Letter to the Editor: The Continuing Challenge of Evaluating RSD Impairment and Disability

1998 ◽  
Vol 3 (5) ◽  
pp. 8-10
Author(s):  
Robert L. Knobler ◽  
Charles N. Brooks ◽  
Leon H. Ensalada ◽  
James B. Talmage ◽  
Christopher R. Brigham
Keyword(s):  
Disability Evaluation ◽  
Body Part ◽  
Loss Of Function ◽  
Regulatory Requirements ◽  
Major Cardiac Event ◽  
Clinical Scenarios ◽  
Impairment Score ◽  
Occupational Activities ◽  
The Difference

Abstract The author of the two-part article about evaluating reflex sympathetic dystrophy (RSD) responds to criticisms that a percentage impairment score may not adequately reflect the disability of an individual with RSD. The author highlights the importance of recognizing the difference between impairment and disability in the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides): impairment is the loss, loss of use, or derangement of any body part, system, or function; disability is a decrease in or the loss or absence of the capacity to meet personal, social, or occupational demands or to meet statutory or regulatory requirements because of an impairment. The disparity between impairment and disability can be encountered in diverse clinical scenarios. For example, a person's ability to resume occupational activities following a major cardiac event depends on medical, social, and psychological factors, but nonmedical factors appear to present the greatest impediment and many persons do not resume work despite significant improvements in functional capacity. A key requirement according to the AMA Guides is objective documentation, and the author agrees that when physicians consider the disability evaluation of people, more issues than those relating to the percentage loss of function should be considered. More study of the relationships among impairment, disability, and quality of life in patients with RSD are required.

ЕКАТЕРИНА ВЕЛИКАЯ И ДИАЛЕКТИКА ПРОСВЕЩЕННОЙ МОНАРХИИ

2020 ◽  
Vol 15 (1) ◽  
pp. 39
Author(s):  
С. И. Дудник ◽  
И. Д. Осипов
Keyword(s):  
Cultural Policy ◽  
Separation Of Powers ◽  
Point Of View ◽  
Human Sciences ◽  
The Rule Of Law ◽  
Political Ideas ◽  
The People ◽  
Specific Interpretation ◽  
The Difference ◽  
Conservative Values

The article discusses the problems of evolution and the formation of the ideology of an enlightened monarchy in Russia. In this regard, the philosophical and political ideas of Catherine the Great, as well as their theoretical and ideological premises, are analyzed. It is noted that the philosophy of education in Russia was closely connected with the concepts of Voltaire, Didro, Montesquieu, Beccaria, Bentham, their views on natural law and human freedom, humanism and the rule of law. These concepts in the philosophy of Catherine received a specific interpretation, due to the sociocultural conditions of Russia. This was manifested in the famous work of Catherine the Great “The Nakaz”, which recognized Montesquieu's argument in favor of the autocracy, but at the same time, his point of view on the separation of powers was rejected. The specificity of the doctrine of enlightened monarchy lies in the combination of liberal and conservative values, which form eclectic forms. This was the dialectic of the supreme power, the difference between the enlightened monarchy and the ideology of absolutism. The article also notes that education in Russia is associated with fundamental socio-political reforms, processes of secularization of culture. At this time, the natural and human sciences are developing. The changes positively influenced the development of medicine, beautification of towns and public education. Also considered are the views on the autocracy of the opposition nobility intelligentsia: A. N. Radishchev and noted that his criticism of the autocracy was determined by an alternative cultural policy, proceeding from the protection of the interests of the people. The doctrine of enlightened monarchy is characterized by internal worldview inconsistency and political inconsistency, which did not allow solving the pressing social problems of the establishment of legal state, democratization of society and the abolition of serfdom.

scholarly journals Differences in a Single Extracellular Residue Underlie Adhesive Functions of Two Zebrafish Aqp0s

Cells ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 2005
Author(s):  
Irene Vorontsova ◽  
James E. Hall ◽  
Thomas F. Schilling ◽  
Noriaki Nagai ◽  
Yosuke Nakazawa
Keyword(s):  
Cell Adhesion ◽  
Single Amino Acid ◽  
Amino Acid Difference ◽  
Adhesion Assay ◽  
Loss Of Function ◽  
Adhesive Properties ◽  
The Difference ◽  
In Vitro Adhesion ◽  
Cell To Cell Adhesion

Aquaporin 0 (AQP0) is the most abundant lens membrane protein, and loss of function in human and animal models leads to cataract formation. AQP0 has several functions in the lens including water transport and adhesion. Since lens optics rely on strict tissue architecture achieved by compact cell-to-cell adhesion between lens fiber cells, understanding how AQP0 contributes to adhesion would shed light on normal lens physiology and pathophysiology. We show in an in vitro adhesion assay that one of two closely related zebrafish Aqp0s, Aqp0b, has strong auto-adhesive properties while Aqp0a does not. The difference appears to be largely due to a single amino acid difference at residue 110 in the extracellular C-loop, which is T in Aqp0a and N in Aqp0b. Similarly, P110 is the key residue required for adhesion in mammalian AQP0, highlighting the importance of residue 110 in AQP0 cell-to-cell adhesion in vertebrate lenses as well as the divergence of adhesive and water permeability functions in zebrafish duplicates.

Study of the Characteristics of the Pulmonary Vein and Superior Vena Cava of Rabbits

2021 ◽  
Vol 11 (1) ◽  
pp. 112-122
Author(s):  
Pan Wang ◽  
Xin-Chun Yang ◽  
Xiu-Lan Liu ◽  
Rong-Feng Bao ◽  
Huai-Yu Ding ◽  
...  
Keyword(s):  
Action Potential ◽  
Pulmonary Vein ◽  
Refractory Period ◽  
Potassium Current ◽  
Superior Vena ◽  
Vena Cava ◽  
Current Intensity ◽  
Left And Right ◽  
The Difference ◽  
Right Atria

Background: This study aims to (1) investigate the characteristics of the action potential and triggering activity of cardiomyocytes in the pulmonary vein (PV) and superior vena cava (SVC) of rabbits and (2) study the features of cation currents in cardiomyocytes in rabbit PV and SVC-inward rectifier potassium current (IK1), transient outward potassium current (Ito), and non-selective cation currents (INSCC). Methods: The standard glass microelectrode and whole-cell patch-clamp techniques were used to record the action potential and various currents in the above cells. Results: (1) Cardiomyocytes in either PV or SVC had longer action potential durations than in the adjacent atrium, and spontaneous early after depolarization (EAD) could occur in both PV and SVC under normal physiological conditions. (2) The action potential in PV cardiomyocytes had a relative refractory period but did not have an absolute refractory period, and this characteristic enabled a premature beat that triggered a second plateau response, which led to EAD. (3) INSCC was found for the first time in the PV, SVC, and atria. (4) The current intensity of IK1, Ito, and INSCC was significantly lower in the PV and SVC than in the left and right atria, and the difference in the current intensity in INSCC could influence the action potential. Conclusions: PV and SVC can both initiate and maintain AF, but PV is the primary ectopic foci in initiating AF. The present study found that the second plateau response was easily induced in cardiomyocytes in PA shortly after depolarization. This was a specific characteristic of the action potential of PV. In addition, we preliminarily analyzed the differences in the main outward currents and noted a voltage-dependent INSCC in both PV and SVC rabbits’ cardiomyocytes. Furthermore, the current intensities of IK1, Ito, and INSCC were significantly lower in the PV and SVC than in the left and right atria, and the difference in the current intensity of INSCC influenced the action potential. The different permeability of INSCC for cations at different phases may play a role in inducing EAD.

Genetic control of dorsal-ventral identity in the telencephalon: opposing roles for Pax6 and Gsh2

Development ◽  
2000 ◽  
Vol 127 (20) ◽  
pp. 4361-4371 ◽  
Author(s):  
H. Toresson ◽  
S.S. Potter ◽  
K. Campbell
Keyword(s):  
Cerebral Cortex ◽  
Gene Function ◽  
Abnormal Development ◽  
Loss Of Function ◽  
Embryonic Mouse ◽  
Molecular Identity ◽  
Mouse Mutants ◽  
Germinal Zone ◽  
Genetic Mechanisms ◽  
Dlx Genes

We have examined the genetic mechanisms that regulate dorsal-ventral identity in the embryonic mouse telencephalon and, in particular, the specification of progenitors in the cerebral cortex and striatum. The respective roles of Pax6 and Gsh2 in cortical and striatal development were studied in single and double loss-of-function mouse mutants. Gsh2 gene function was found to be essential to maintain the molecular identity of early striatal progenitors and in its absence the ventral telencephalic regulatory genes Mash1 and Dlx are lost from most of the striatal germinal zone. In their place, the dorsal regulators, Pax6, neurogenin 1 and neurogenin 2 are found ectopically. Conversely, Pax6 is required to maintain the correct molecular identity of cortical progenitors. In its absence, neurogenins are lost from the cortical germinal zone and Gsh2, Mash1 and Dlx genes are found ectopically. These reciprocal alterations in cortical and striatal progenitor specification lead to the abnormal development of the cortex and striatum observed in Pax6 (small eye) and Gsh2 mutants, respectively. In support of this, double homozygous mutants for Pax6 and Gsh2 exhibit significant improvements in both cortical and striatal development compared with their respective single mutants. Taken together, these results demonstrate that Pax6 and Gsh2 govern cortical and striatal development by regulating genetically opposing programs that control the expression of each other as well as the regionally expressed developmental regulators Mash1, the neurogenins and Dlx genes in telencephalic progenitors.

scholarly journals Stochastic left–right neuronal asymmetry in Caenorhabditis elegans

2016 ◽  
Vol 371 (1710) ◽  
pp. 20150407 ◽  
Author(s):  
Amel Alqadah ◽  
Yi-Wen Hsieh ◽  
Rui Xiong ◽  
Chiou-Fen Chuang
Keyword(s):  
Caenorhabditis Elegans ◽  
Molecular Mechanisms ◽  
Neurological Diseases ◽  
Calcium Signalling ◽  
Model Organism ◽  
Brain Asymmetry ◽  
C Elegans ◽  
Left And Right ◽  
Left Right Asymmetry ◽  
Neuronal Asymmetry

Left–right asymmetry in the nervous system is observed across species. Defects in left–right cerebral asymmetry are linked to several neurological diseases, but the molecular mechanisms underlying brain asymmetry in vertebrates are still not very well understood. The Caenorhabditis elegans left and right amphid wing ‘C’ (AWC) olfactory neurons communicate through intercellular calcium signalling in a transient embryonic gap junction neural network to specify two asymmetric subtypes, AWC OFF (default) and AWC ON (induced), in a stochastic manner. Here, we highlight the molecular mechanisms that establish and maintain stochastic AWC asymmetry. As the components of the AWC asymmetry pathway are highly conserved, insights from the model organism C. elegans may provide a window onto how brain asymmetry develops in humans. This article is part of the themed issue ‘Provocative questions in left–right asymmetry’.

Errors in Estimating the Orientation of Dot Patterns

Perception ◽  
1989 ◽  
Vol 18 (2) ◽  
pp. 237-242 ◽  
Author(s):  
P Lánský ◽  
Naum Yakimoff ◽  
T Radil ◽  
L Mitrani
Keyword(s):  
Pattern Analysis ◽  
Frontoparallel Plane ◽  
The Subject ◽  
Left And Right ◽  
The Mean ◽  
The Difference

The error in estimating the orientation of a dot pattern was measured as the difference between the orientation of the least-squared-distances line (LS-line) of the pattern and the orientation of a line adjusted by the subject to match the perceived orientation of the pattern. Analysis of the mean errors (averaged over ten subjects) obtained for one hundred patterns confirmed that the orientation of the LS-line represents the orientation of elongated dot-patterns. It is shown that estimated orientation was systematically biased towards the nearest 45° oblique meridian. This bias points to the importance of the ±45° directions as natural norms for left- and right-side tilt in the frontoparallel plane.

scholarly journals Mice With Monoallelic GNAO1 Loss Exhibit Reduced Inhibitory Synaptic Input To Cerebellar Purkinje Cells

2021 ◽  
Author(s):  
Huijie Feng ◽  
Yukun Yuan ◽  
Michael R Williams ◽  
Alex Roy ◽  
Jeffrey Leipprandt ◽  
...  
Keyword(s):  
Synaptic Transmission ◽  
Purkinje Cells ◽  
Gabab Receptor ◽  
Molecular Layer ◽  
Loss Of Function ◽  
Whole Cell Patch Clamp ◽  
The Difference ◽  
G Protein Alpha Subunit ◽  
Cerebellar Purkinje Cells

GNAO1 encodes Gαo, a heterotrimeric G protein alpha subunit in the Gi/o family. In this report, we used a Gnao1 mouse model G203R previously described as a gain-of-function Gnao1 mutant with movement abnormalities and enhanced seizure susceptibility. Here, we report an unexpected second mutation resulting in a loss-of-function Gαo protein and describe alterations in central synaptic transmission. Whole cell patch clamp recordings from Purkinje cells (PCs) in acute cerebellar slices from Gnao1 mutant mice showed significantly lower frequencies of spontaneous and miniature inhibitory postsynaptic currents (sIPSCs and mIPSCs) compared to WT mice. There was no significant change in sEPSCs or mEPSCs. Whereas mIPSC frequency was reduced, mIPSC amplitudes were not affected, suggesting a presynaptic mechanism of action. A modest decrease in the number of molecular layer interneurons was insufficient to explain the magnitude of IPSC suppression. Paradoxically, Gi/o inhibitors (pertussis toxin), enhanced the mutant-suppressed mIPSC frequency and eliminated the difference between WT and Gnao1 mice. While GABAB receptor regulates mIPSCs, neither agonists nor antagonists of this receptor altered function in the mutant mouse PCs. This study is the first electrophysiological investigation of the role of Gi/o protein in cerebellar synaptic transmission using an animal model with a loss-of-function Gi/o protein.

scholarly journals Left-right and upper-lower light sensitivity asymmetry in visual field defects caused by pituitary adenoma: a retrospective observational study

2019 ◽  
Author(s):  
Yumi Kotoda ◽  
Masakazu Kotoda ◽  
Masakazu Ogiwara ◽  
Hiroyuki Kinouchi ◽  
Hiroyuki Iijima
Keyword(s):  
Pituitary Adenoma ◽  
Visual Field ◽  
Light Sensitivity ◽  
Visual Field Defects ◽  
Lower Visual Field ◽  
Lower Quadrant ◽  
Lower Light ◽  
Left And Right ◽  
Left Right Asymmetry ◽  
Field Defects

Abstract Background While bitemporal visual field defects are characteristic in pituitary adenoma cases, it is rare to have complete bitemporal hemianopsia that is symmetrical in both eyes and has absolute scotoma throughout both temporal hemifields. Although several researches have investigated asymmetric visual field defects in patients with pituitary adenoma, no precise investigation with statistical analysis regarding the inter-eye and intra-eye symmetry of visual field defects has yet been reported. In this study, we conducted quantitative analysis to explore the asymmetric properties of visual field defects in pituitary adenoma patients. Methods Preoperative Humphrey 30-2 perimetry results were reviewed retrospectively using the charts of 28 pituitary adenoma patients who underwent surgery. Inter-eye light sensitivity comparisons of the temporal and nasal hemifields between the left and right eyes were conducted in each patient to study left-right asymmetry. Upper-lower asymmetry was investigated by comparing the frequency of severe scotoma (light sensitivity 5 dB or less) in the upper and lower visual field quadrants in the temporal and nasal hemifields. Results Left-right asymmetry was demonstrated in 61% of cases in the temporal hemifield and in 57% of cases in the nasal hemifield. Severe scotoma test points were investigated in the worse eye of each patient and were more frequent in the superotemporal quadrant of the visual field compared with the inferotemporal quadrant (P = 0.00029) and in the inferonasal quadrant compared to the superonasal quadrant (P = 0.00268). Conclusions Asymmetric visual field defects between left and right eyes are common in patients with pituitary adenoma. Severe scotoma is more frequent in the upper quadrant of the temporal hemifield and in the lower quadrant of the nasal hemifield.

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