scholarly journals An ultrastructural examination of the role of cell membrane surface coat material during neurulation.

1975 ◽  
Vol 64 (1) ◽  
pp. 172-181 ◽  
Author(s):  
D Moran ◽  
R W Rice
Keyword(s):  
Neural Tube ◽  
Membrane Surface ◽  
Progressive Increase ◽  
Cellular Migration ◽  
Surface Coat ◽  
Positive Material ◽  
Specific Distribution ◽  
Lateral Ridge ◽  
Coat Material

Data from neural crest cultures indicate that cell surface coat material (CSM) is directly involved in cellular migration and events surrounding differentiation. To investigate whether the CSM also has a morphogenetic role, embryos of the amphibian Ambystoma maculatum were examined ultrastructurally throughout the stages of neurulation. Segments of the neural axis were fixed in glutaraldehyde-containing Alcian blue 8GX, which reportedly enhances preservation of CSM, and were postfixed in OsO4 containing 1 percent lanthanum nitrate, which stains the CSM. The medial groove formed by the appearance of the neural ridges contains a large amount of CSM and numerous vesicles coated with lanthanum-positive material. In contrast, the lateral ridge surfaces are covered by a small amount of uniformly distributed CSM and a paucity of vesicles. As the ridges begin to fold there is a progressive increase in the amount of CSM within the presumptive neural tube region. Further convergence of the neural folds is accompanied by an increase of CSM at their leading edges. As the folds approximate each other, lanthanum-positive material physically bridges the gap. However, as the apposing tissue actually abuts to form the neural tube, no CSM is observed in the remaining interspace. The specific distribution and sequential accumulation of cell CSM during the events of neurulation strongly suggest its direct participation in the morphogenetic process.

Role of spectrin in membrane fusion and in shape change of human erythrocyte ghost

1978 ◽  
Vol 36 (2) ◽  
pp. 328-329
Author(s):  
Hideo Hayashi ◽  
Yoshikazu Hirai ◽  
John T. Penniston
Keyword(s):  
Conformational Changes ◽  
Human Erythrocyte ◽  
Shape Change ◽  
Membrane Surface ◽  
Slight Modification ◽  
Active Role ◽  
Main Role ◽  
Bank Blood ◽  
Human Erythrocyte Ghost

Spectrin is a membrane associated protein most of which properties have been tentatively elucidated. A main role of the protein has been assumed to give a supporting structure to inside of the membrane. As reported previously, however, the isolated spectrin molecule underwent self assemble to form such as fibrous, meshwork, dispersed or aggregated arrangements depending upon the buffer suspended and was suggested to play an active role in the membrane conformational changes. In this study, the role of spectrin and actin was examined in terms of the molecular arrangements on the erythrocyte membrane surface with correlation to the functional states of the ghosts.Human erythrocyte ghosts were prepared from either freshly drawn or stocked bank blood by the method of Dodge et al with a slight modification as described before. Anti-spectrin antibody was raised against rabbit by injection of purified spectrin and partially purified.

Role of PKC isozymes in water transport in toad urinary bladder

1991 ◽  
Vol 49 ◽  
pp. 302-303
Author(s):  
A.J. Mia ◽  
L.X. Oakford ◽  
T. Yorio
Keyword(s):  
Urinary Bladder ◽  
Apical Membrane ◽  
Membrane Surface ◽  
Protein A ◽  
Cell Types ◽  
Leukemic Cells ◽  
Toad Urinary Bladder ◽  
Pkc Isozymes ◽  
Antibody Labeling

Protein kinase C (PKC) isozymes, when activated, are translocated to particulate membrane fractions for transport to the apical membrane surface in a variety of cell types. Evidence of PKC translocation was demonstrated in human megakaryoblastic leukemic cells, and in cardiac myocytes and fibroblasts, using FTTC immunofluorescent antibody labeling techniques. Recently, we reported immunogold localizations of PKC subtypes I and II in toad urinary bladder epithelia, following 60 min stimulation with Mezerein (MZ), a PKC activator, or antidiuretic hormone (ADH). Localization of isozyme subtypes I and n was carried out in separate grids using specific monoclonal antibodies with subsequent labeling with 20nm protein A-gold probes. Each PKC subtype was found to be distributed singularly and in discrete isolated patches in the cytosol as well as in the apical membrane domains. To determine if the PKC isozymes co-localized within the cell, a double immunogold labeling technique using single grids was utilized.

Health and social problems associated with HIV infection and AIDS in the professional activity of specialists with secondary medical education

2020 ◽  
pp. 5-13
Author(s):  
L. Guseva
Keyword(s):  
Medical Education ◽  
Hiv Infection ◽  
Clinical Signs ◽  
Modern Society ◽  
Progressive Increase ◽  
Professional Activity ◽  
Infected People ◽  
Immunodeficiency Virus ◽  
Epidemiological Characteristics

The article considers urgent problem of modern society – progressive increase in the number of people infected with the human immunodeficiency virus (HIV). Epidemiological characteristics of the pathogen are given, clinical signs of the disease and a modern strategy aimed at reducing the number of infected people are presented. The role of specialists with secondary medical education in the implementation of the Strategy aimed at combating the spread of HIV infection epidemic in the Russian Federation is emphasized.

scholarly journals The Role of Src Kinase in Macrophage-Mediated Inflammatory Responses

2012 ◽  
Vol 2012 ◽  
pp. 1-18 ◽  
Author(s):  
Se Eun Byeon ◽  
Young-Su Yi ◽  
Jueun Oh ◽  
Byong Chul Yoo ◽  
Sungyoul Hong ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Immune Responses ◽  
Inflammatory Responses ◽  
Inflammatory Diseases ◽  
Src Kinase ◽  
Multiple Roles ◽  
Cellular Migration ◽  
Pharmaceutical Drugs ◽  
Tyrosine Protein Kinase

Src kinase (Src) is a tyrosine protein kinase that regulates cellular metabolism, survival, and proliferation. Many studies have shown that Src plays multiple roles in macrophage-mediated innate immunity, such as phagocytosis, the production of inflammatory cytokines/mediators, and the induction of cellular migration, which strongly implies that Src plays a pivotal role in the functional activation of macrophages. Macrophages are involved in a variety of immune responses and in inflammatory diseases including rheumatoid arthritis, atherosclerosis, diabetes, obesity, cancer, and osteoporosis. Previous studies have suggested roles for Src in macrophage-mediated inflammatory responses; however, recently, new functions for Src have been reported, implying that Src functions in macrophage-mediated inflammatory responses that have not been described. In this paper, we discuss recent studies regarding a number of these newly defined functions of Src in macrophage-mediated inflammatory responses. Moreover, we discuss the feasibility of Src as a target for the development of new pharmaceutical drugs to treat macrophage-mediated inflammatory diseases. We provide insights into recent reports regarding new functions for Src that are related to macrophage-related inflammatory responses and the development of novel Src inhibitors with strong immunosuppressive and anti-inflammatory properties, which could be applied to various macrophage-mediated inflammatory diseases.

scholarly journals Genetic disruption of calpain correlates with loss of membrane blebbing and differential expression of RhoGDI-1, cofilin and tropomyosin

2008 ◽  
Vol 411 (3) ◽  
pp. 657-666 ◽  
Author(s):  
Anna K. Larsen ◽  
René Lametsch ◽  
John S. Elce ◽  
Jørgen K. Larsen ◽  
Bo Thomsen ◽  
...  
Keyword(s):  
Membrane Surface ◽  
Proteome Analysis ◽  
Time Lapse ◽  
Wild Type ◽  
Genetic Rescue ◽  
Dynamic Regulation ◽  
Membrane Blebbing ◽  
Signalling Molecules ◽  
Membrane Blebs

Dynamic regulation of the actin cytoskeleton is important for cell motility, spreading and the formation of membrane surface extensions such as lamellipodia, ruffles and blebs. The ubiquitous calpains contribute to integrin-mediated cytoskeletal remodelling during cell migration and spreading, by cleavage of focal adhesion components and signalling molecules. In the present study, the live-cell morphology of calpain-knockout and wild-type cells was examined by time-lapse fluorescence microscopy, and a role of calpain in mediating the formation of sporadic membrane blebs was established. Membrane blebbing was significantly reduced in calpain-knockout cells, and genetic rescue fully restored the wild-type phenotype in knockout cells. Proteomic comparison of wild-type and knockout cells identified decreased levels of RhoGDI-1 (Rho GDP-dissociation inhibitor) and cofilin 1, and increased levels of tropomyosin in calpain-knockout cells, suggesting a role of calpain in regulating membrane extensions involving these proteins. RhoGDI, cofilin and tropomyosin are known regulators of actin filament dynamics and membrane extensions. The reduced levels of RhoGDI-1 in calpain-knockout cells observed by proteome analysis were confirmed by immunoblotting. Genetic rescue of the calpain-knockout cells enhanced RhoGDI-1-expression 2-fold above that normally present in wild-type cells. These results suggest a regulatory connection between calpain and RhoGDI-1 in promoting formation of membrane blebs.

scholarly journals Netrin-1 in Atherosclerosis: Relationship between Human Macrophage Intracellular Levels and In Vivo Plaque Morphology

Biomedicines ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 168
Author(s):  
Susanna Fiorelli ◽  
Nicola Cosentino ◽  
Benedetta Porro ◽  
Franco Fabbiocchi ◽  
Giampaolo Niccoli ◽  
...  
Keyword(s):  
Progressive Increase ◽  
Human Macrophage ◽  
Plaque Morphology ◽  
Artery Disease ◽  
Atherosclerotic Process ◽  
And Function ◽  
And Control ◽  
Macrophage Accumulation

Netrin-1 is a laminin-like protein that plays a pivotal role in cell migration and, according to the site of its release, exerts both pro and anti-atherosclerotic functions. Macrophages, key cells in atherosclerosis, are heterogeneous in morphology and function and different subpopulations may support plaque progression, stabilization, and/or regression. Netrin-1 was evaluated in plasma and, together with its receptor UNC5b, in both spindle and round monocyte-derived macrophages (MDMs) morphotypes from coronary artery disease (CAD) patients and control subjects. In CAD patients, plaque features were detected in vivo by optical coherence tomography. CAD patients had lower plasma Netrin-1 levels and a higher MDMs expression of both protein and its receptor compared to controls. Specifically, a progressive increase in Netrin-1 and UNC5b was evidenced going from controls to stable angina (SA) and acute myocardial infarction (AMI) patients. Of note, spindle MDMs of AMI showed a marked increase of both Netrin-1 and its receptor compared to spindle MDMs of controls. UNC5b expression is always higher in spindle compared to round MDMs, regardless of the subgroup. Finally, CAD patients with higher intracellular Netrin-1 levels showed greater intraplaque macrophage accumulation in vivo. Our findings support the role of Netrin-1 and UNC5b in the atherosclerotic process.

Abstract 644: Role of Micro RNA LET-7F in Cigarette Smoke-Induced Impairment of Neovascularization

2015 ◽  
Vol 35 (suppl_1) ◽  
Author(s):  
Wahiba Dhahri ◽  
Sylvie Dussault ◽  
Paola Haddad ◽  
Julie Turgeon ◽  
Sophie Tremblay ◽  
...  
Keyword(s):  
Cigarette Smoke ◽  
Vascular Endothelial Cells ◽  
Capillary Density ◽  
Tube Formation ◽  
Micro Rna ◽  
Cellular Migration ◽  
Mirna Array ◽  
Inhibition Of Angiogenesis

Background: Exposure to cigarette smoke is associated with impaired neovascularization in response to ischemia. The precise mechanisms involved in that process remain to be determined. Micro RNA (miR) are emerging as key regulators of several physiological processes, including angiogenesis. Here we investigated the potential role of miRs for the modulation of neovascularization in the context of cigarette smoking. Methods and Results: Human Umbilical Vascular Endothelial Cells (HUVECs) were exposed or not to cigarette smoke extracts (CSE). Using Affimetrix GeneChip miRNA array analysis, we found that the pro-angiogenic miR let-7f was downregulated by 40% in HUVECs exposed to CSE. Using an inhibitor of let-7f, we demonstrated reduced migration and tube formation in HUVECs, reproducing the phenotype induced by CSE. A let-7f mimic could rescue cellular migration and tube formation in HUVECs exposed to CSE. Moreover, the expression of let-7f is significantly reduced in the ischemic muscles of mice exposed to cigarette smoke (CS). In vivo, hindlimb ischemia was surgically provoked by femoral artery removal to mice exposed (SMK) or not to CS for two weeks with a local injection of a control or a let-7f mimic. Let-7f mimic could rescue blood flow recuperation and capillary density in ischemic muscles 21 days post-ischemia associated with improved mobility. We found that CS was associated with reduced number of endothelial progenitor cells (EPCs) and impairment of angiogenic activities. Importantly, let-7f mimic rescued EPC number and EPC functional activities in SMK group. TGF-β-RI and HIF1AN are predicted to be targeted by let-7f and both are increased in SMK mice, whereas the expression of HIF-1a and VEGF are reduced in these mice. Interestingly, SMK mice injected with a let-7f mimic have decreased muscle expression of TGF-β-RI and HIF1AN associated with normalized HIF-1 and VEGF expression. Conclusion: Our results suggest that a reduction in the expression of let-7f could be involved in the cigarette smoke-induced inhibition of angiogenesis through modulation of TGF-β-RI and HIF1AN. Overexpression of let-7f using a miR mimic could constitute a novel therapeutic strategy to improve ischemia-induced neovascularization in pathological conditions.

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