Morphological and Functional Aspects of Cellular Hemostatic Mechanisms

1996 ◽  
Vol 16 (02) ◽  
pp. 78-87 ◽  
Author(s):  
J. G. White
Keyword(s):  
Low Voltage ◽  
Shape Change ◽  
Biochemical Alterations ◽  
Heart Attacks ◽  
Fundamental Knowledge ◽  
Functional Aspects ◽  
Comprehensive Picture ◽  
Platelet Reaction ◽  
And Function ◽  
Plug Formation

SummaryTransmission, scanning and low-voltage, high resolution scanning electron microscopy have provided fundamental knowledge of relationships between plate-let structure and function. In combination with ultrastructural cytochemistry and immunocytochemistry, basic aspects of shape change, pseudopod extension, internal transformation, secretion, adhesion, aggregation, spreading, hemostatic plug formation and thrombus development have been defined. The morphological events of the platelet reaction in hemostasis have been linked to biochemical alterations. The result is a comprehensive picture of cellular aspects of hemosta-sis. This knowledge provides a basis for designing programs of treatment for heart attacks, strokes and other occlusive vascular disorders, as well as for their prevention.

scholarly journals Telomere Length and Oxidative Stress and Its Relation with Metabolic Syndrome Components in the Aging

Biology ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 253
Author(s):  
Graciela Gavia-García ◽  
Juana Rosado-Pérez ◽  
Taide Laurita Arista-Ugalde ◽  
Itzen Aguiñiga-Sánchez ◽  
Edelmiro Santiago-Osorio ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Metabolic Syndrome ◽  
Telomere Length ◽  
Scientific Evidence ◽  
Telomeric Dna ◽  
Biochemical Alterations ◽  
The Metabolic Syndrome ◽  
Age Related ◽  
And Function

A great amount of scientific evidence supports that Oxidative Stress (OxS) can contribute to telomeric attrition and also plays an important role in the development of certain age-related diseases, among them the metabolic syndrome (MetS), which is characterised by clinical and biochemical alterations such as obesity, dyslipidaemia, arterial hypertension, hyperglycaemia, and insulin resistance, all of which are considered as risk factors for type 2 diabetes mellitus (T2DM) and cardiovascular diseases, which are associated in turn with an increase of OxS. In this sense, we review scientific evidence that supports the association between OxS with telomere length (TL) dynamics and the relationship with MetS components in aging. It was analysed whether each MetS component affects the telomere length separately or if they all affect it together. Likewise, this review provides a summary of the structure and function of telomeres and telomerase, the mechanisms of telomeric DNA repair, how telomere length may influence the fate of cells or be linked to inflammation and the development of age-related diseases, and finally, how the lifestyles can affect telomere length.

A Dynamic Route to Structure and Function: Recent Advances in Imine-Based Organic Nanostructured Materials

2013 ◽  
Vol 66 (1) ◽  
pp. 9 ◽  
Author(s):  
Yi Liu ◽  
Zhan-Ting Li
Keyword(s):  
Self Assembly ◽  
Reaction System ◽  
Functional Materials ◽  
Building Blocks ◽  
The Self ◽  
Interlocked Molecules ◽  
Functional Aspects ◽  
Imine Bond ◽  
And Function ◽  
Dynamic Route

The chemistry of imine bond formation from simple aldehyde and amine precursors is among the most powerful dynamic covalent chemistries employed for the construction of discrete molecular objects and extended molecular frameworks. The reversible nature of the C=N bond confers error-checking and proof-reading capabilities in the self-assembly process within a multi-component reaction system. This review highlights recent progress in the self-assembly of complex organic molecular architectures that are enabled by dynamic imine chemistry, including molecular containers with defined geometry and size, mechanically interlocked molecules, and extended frameworks and polymers, from building blocks with preprogrammed steric and electronic information. The functional aspects associated with the nanometer-scale features not only place these dynamically constructed nanostructures at the frontier of materials sciences, but also bring unprecedented opportunities for the discovery of new functional materials.

scholarly journals Functional identification of potential non-canonical N-glycosylation sites within Cav3.2 T-type calcium channels

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Vendula Ficelova ◽  
Ivana A. Souza ◽  
Leos Cmarko ◽  
Maria A. Gandini ◽  
Robin N. Stringer ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Calcium Channels ◽  
Low Voltage ◽  
Consensus Sequence ◽  
Site Directed Mutagenesis ◽  
Post Translational Modification ◽  
Functional Identification ◽  
Electrophysiological Recordings ◽  
Nervous System Function ◽  
And Function

Abstract Low-voltage-activated T-type calcium channels are important contributors to nervous system function. Post-translational modification of these channels has emerged as an important mechanism to control channel activity. Previous studies have documented the importance of asparagine (N)-linked glycosylation and identified several asparagine residues within the canonical consensus sequence N-X-S/T that is essential for the expression and function of Cav3.2 channels. Here, we explored the functional role of non-canonical N-glycosylation motifs in the conformation N-X-C based on site directed mutagenesis. Using a combination of electrophysiological recordings and surface biotinylation assays, we show that asparagines N345 and N1780 located in the motifs NVC and NPC, respectively, are essential for the expression of the human Cav3.2 channel in the plasma membrane. Therefore, these newly identified asparagine residues within non-canonical motifs add to those previously reported in canonical sites and suggest that N-glycosylation of Cav3.2 may also occur at non-canonical motifs to control expression of the channel in the plasma membrane. It is also the first study to report the functional importance of non-canonical N-glycosylation motifs in an ion channel.

scholarly journals Type of Agitation and Platelet Viability and Function After 22°C Storage: Correlation with Maintenance of Discoid Shape

1977 ◽  
Author(s):  
S. Holme ◽  
K. Vaidja ◽  
S. Murphy
Keyword(s):  
Platelet Count ◽  
Shape Change ◽  
Storage Conditions ◽  
C Storage ◽  
Platelet Morphology ◽  
Citrate Dextrose ◽  
And Function ◽  
Change Response

Platelet viability as measured by in vivo 51cr recovery, platelet morphology, and in vitro aggregation with ADP and thrombin were studied with platelet concentrates (PC) stored for transfusion under carefully controlled conditions. The PC were prepared from whole blood with citrate-dextrose-phosphate as anticoagulant. The platelet count was kept between 0.8 − 1.6 × 106 platelets per mm3 in a volume of 50 ml. The PC were stored in containers constructed of polyethylene (PE) or Polyvinylchloride (PVC) at 22°C for 72 hours. The bags were placed on a horizontal shaker or a ferris wheel type of apparatus during storage. No significant changes in pH or platelet count were observed during storage. PC stored on the wheel showed a moderate loss of viability and marked loss of aggregation response compared to PC on the shaker. Under optimal conditions with PC in PE on the shaker maximal rate of aggregation was reduced only 26% compared to fresh PC. PC stored in PVC showed a statistically significant greater decrease. A good correlation was observed between the percentage of discoid platelets present in the PC as judged by phase microscopy and the extent of platelet shape change response to ADP. Both parameters correlated positively with in vivo 51Cr recovery. We conclude: 1) The type of agitation used significantly effects maintenance of platelet viability and function during storage. 2) Under the conditions used, in vitro function was better preserved in PE than in PVC bags. 3) In vitro function is not inevitably lost during storage at 22°C, but is critically dependent on storage conditions. 4) In vivo platelet viability (51Cr recovery) correlates with maintenance of disc shape. The latter can be quantitated by the shape change response with ADP.

A study of Japanese back channels

1998 ◽  
Vol 15 ◽  
pp. 77-92
Author(s):  
Duck-Young Lee ◽  
Chiharu Mukai
Keyword(s):  
Native Speakers ◽  
Native Speaker ◽  
Advanced Level ◽  
Functional Aspects ◽  
Japanese Learners ◽  
And Function

Abstract This study presents findings from an analysis of the conversational data involving the Japanese back channel with special attention to the comparison of back channel behaviour between Japanese native speakers and Japanese learners at an advanced level. While the analysis is based on four aspects of the back channel (i.e. form, frequency, location and function), the study reveals that native speakers and Japanese learners show significant differences particularly in the locational and functional aspects. There were also trends that the native speaker tends to use back channels in a way of supporting and encouraging the learner to participate in the conversation.

scholarly journals GPR56/ADGRG1 is a platelet collagen-responsive GPCR and hemostatic sensor of shear force

2020 ◽  
Vol 117 (45) ◽  
pp. 28275-28286 ◽  
Author(s):  
Jennifer Yeung ◽  
Reheman Adili ◽  
Emily N. Stringham ◽  
Rong Luo ◽  
Alexander Vizurraga ◽  
...  
Keyword(s):  
Blood Flow ◽  
G Protein ◽  
Shear Force ◽  
Platelet Adhesion ◽  
Shape Change ◽  
Blood Perfusion ◽  
Perfusion Studies ◽  
Platelet Receptor ◽  
Plug Formation ◽  
Platelet Shape

Circulating platelets roll along exposed collagen at vessel injury sites and respond with filipodia protrusion, shape change, and surface area expansion to facilitate platelet adhesion and plug formation. Various glycoproteins were considered to be both collagen responders and mediators of platelet adhesion, yet the signaling kinetics emanating from these receptors do not fully account for the rapid platelet cytoskeletal changes that occur in blood flow. We found the free N-terminal fragment of the adhesion G protein-coupled receptor (GPCR) GPR56 in human plasma and report that GPR56 is the platelet receptor that transduces signals from collagen and blood flow-induced shear force to activate G protein 13 signaling for platelet shape change.Gpr56−/−mice have prolonged bleeding, defective platelet plug formation, and delayed thrombotic occlusion. Human and mouse blood perfusion studies demonstrated GPR56 and shear-force dependence of platelet adhesion to immobilized collagen. Our work places GPR56 as an initial collagen responder and shear-force transducer that is essential for platelet shape change during hemostasis.

scholarly journals Functional Aspects of Seminal Plasma in Bird Reproduction

2020 ◽  
Vol 21 (16) ◽  
pp. 5664
Author(s):  
Julian Santiago-Moreno ◽  
Elisabeth Blesbois
Keyword(s):  
Seminal Plasma ◽  
Ion Homeostasis ◽  
Sperm Concentration ◽  
Cellular Functions ◽  
Functional Aspects ◽  
Reproductive Techniques ◽  
Sperm Survival ◽  
Protein Components ◽  
And Function

This review provides an updated overview of the seminal plasma composition, and the role of metabolic and protein components on the sperm function of avian species. In addition, the implication of seminal plasma on assisted reproductive techniques of birds was discussed. The semen of birds usually has exceptionally high sperm concentration with relatively little seminal plasma, but this contributes to very fast changes in sperm metabolism and function. The biochemical characteristics and physiological roles of the various seminal plasma components in birds (carbohydrates, lipids, amino acids, hormones, and proteins) are poorly understood. Seminal plasma content of proteins has an action on most cellular functions: metabolism, immunity, oxido-reduction regulation, proteolysis, apoptosis, ion homeostasis, and antimicrobial defenses. The variable amount of many proteins is related to a different fertility capacity of poultry sperm. The role of seminal plasma on semen conservation (chilling and freezing) remains largely a matter of speculation, as both inhibitory and stimulating effects have been found. Whereas the presence of seminal plasma did not seem to affect the sperm survival after freezing–thawing, DNA fragmentation is lower in the absence of seminal plasma. The molecular basis of the influence of seminal plasma on sperm cryo-resistance was also discussed in the present review.

scholarly journals Anatomy and function of the fornix in the context of its potential as a therapeutic target

2020 ◽  
Vol 91 (5) ◽  
pp. 547-559 ◽  
Author(s):  
Suhan Senova ◽  
Anton Fomenko ◽  
Elise Gondard ◽  
Andres M Lozano
Keyword(s):  
Memory Deficits ◽  
Oscillatory Dynamics ◽  
Stimulation Parameters ◽  
Societal Burden ◽  
Functional Aspects ◽  
Optimal Target ◽  
And Function ◽  
Preclinical And Clinical Studies ◽  
Deep Brain

The fornix is a white matter bundle located in the mesial aspect of the cerebral hemispheres, which connects various nodes of a limbic circuitry and is believed to play a key role in cognition and episodic memory recall. As the most prevalent cause of dementia, Alzheimer’s disease (AD) dramatically impairs the quality of life of patients and imposes a significant societal burden on the healthcare system. As an established treatment for movement disorders, deep brain stimulation (DBS) is currently being investigated in preclinical and clinical studies for treatment of memory impairment in AD by modulating fornix activity. Optimal target and stimulation parameters to potentially rescue memory deficits have yet to be determined. The aim of this review is to consolidate the structural and functional aspects of the fornix in the context of neuromodulation for memory deficits. We first present an anatomical and functional overview of the fibres and structures interconnected by the fornix. Recent evidence from preclinical models suggests that the fornix is subdivided into two distinct functional axes: a septohippocampal pathway and a subiculothalamic pathway. Each pathway’s target and origin structures are presented, followed by a discussion of their oscillatory dynamics and functional connectivity. Overall, neuromodulation of each pathway of the fornix is discussed in the context of evidence-based forniceal DBS strategies. It is not yet known whether driving fornix activity can enhance cognition—optimal target and stimulation parameters to rescue memory deficits have yet to be determined.

Fc receptors for IgG on human neutrophils: analysis of structure and function by using monoclonal antibody probes.

1985 ◽  
Vol 31 (9) ◽  
pp. 1444-1448 ◽  
Author(s):  
J S Rosenberg ◽  
M J Melnicoff ◽  
P Wilding
Keyword(s):  
Monoclonal Antibody ◽  
Fc Receptors ◽  
Myelogenous Leukemia ◽  
Human Neutrophils ◽  
Fc Gamma Receptor ◽  
Immunogold Staining ◽  
Cell Functions ◽  
Gamma Receptor ◽  
Functional Aspects ◽  
And Function

Abstract Structural and functional characteristics of Fc receptors for IgG (Fc gamma) on human neutrophils were examined with two monoclonal antibody probes specific for the Fc gamma receptors, Leu 11b and 3G8. To determine the distribution, density, and membrane mobility of the Fc gamma receptor, we used immunogold staining techniques, flow cytometry analysis, and fluorescence microscopy. Both 3G8 and Leu 11b inhibited several cell functions, thereby depicting the regulatory role of the Fc gamma receptor in mediating neutrophil activities. Among the functions studied were release of lysosomal enzymes, release of superoxide anion (O2-), and Fc-dependent rosette formation and phagocytosis. The densities of Fc gamma determinants recognized by Leu 11b and 3G8 on cells from a patient with chronic myelogenous leukemia were less than the density of epitopes on neutrophils from a normal individual. Taken together, the detailed analysis of physical and functional aspects of the Fc gamma receptor on neutrophils described in this study serve as a model for further assessment of the use of Fc gamma phenotyping of cells as a diagnostic tool.

Neuroactive peptides as markers of retinal ganglion cell populations that differ in anatomical organization and function

1988 ◽  
Vol 1 (1) ◽  
pp. 73-81 ◽  
Author(s):  
Rodrigo O. Kuljis ◽  
Harvey J. Karten
Keyword(s):  
Retinal Ganglion Cells ◽  
Optic Tectum ◽  
Ganglion Cells ◽  
Retinal Ganglion ◽  
Pharmacological Manipulation ◽  
Functional Aspects ◽  
Neuroactive Peptides ◽  
Retinofugal Projections ◽  
And Function

AbstractRecent immunocytochemical studies indicate the existence of several classes of peptide- (PRGC) and catecholamine-containing retinal ganglion cells in anurans, birds, and mammals. Different classes of PRGC project to discrete and seemingly unique layers in the retino-recipient portion of the anuran and avian optic tectum. Peptide-containing retinofugal projections to the frog tectum originate early in development, and are reestablished by some classes of PRGC during regeneration of the optic nerve. These findings indicate that chemically specific, parallel retinofugal pathways presumably subserve different functional aspects of vision in vertebrates. Exciting prospects for research include the correlation of physiologically with immunocytochemically defined classes of retinal ganglion cells, the analysis of the possible role of neuroactive peptides in retinofugal transmission, and the pharmacological manipulation of putative peptidergic retinofugal pathways to analyze their role in visual function.

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