scholarly journals Oocyte Activation Failure: Physiological and Clinical Aspects

2019 ◽  
Author(s):  
Nina Hojnik ◽  
Borut Kovačič
Keyword(s):  
Clinical Aspects ◽  
Oocyte Activation

Oocyte activation: fundamental and clinical aspects

2020 ◽  
Vol 19 (5) ◽  
pp. 77-85
Author(s):  
Yu.Yu. Gromenko ◽  
◽  
E.F. Galimova ◽  
D.D. Gromenko ◽  
K.Sh. Galimov ◽  
...  
Keyword(s):  
Phospholipase C ◽  
Calcium Ions ◽  
Therapeutic Option ◽  
Clinical Aspects ◽  
Oocyte Activation ◽  
Molecular Events ◽  
General Aspects ◽  
Artificial Activation ◽  
Main Factor

Fertilization and embryogenesis in mammals are initiated by a series of molecular events called ‘oocyte activation.’ This process includes a number of specific fluctuations of calcium ions in the cell with the involvement of specific phospholipase C ζ (PLCζ), an enzyme of spermatozoa introduced into the ooplasm during gamete fusion and recognized as the main factor responsible for inducing oocyte activation. Substantial biochemical and clinical evidence supports the role of PLCζ in this fundamental process, which is very important for the diagnosis and treatment of infertility. This literature review aims to provide some insight in the structure, mechanism of action, and regulation of PLCζ activity in healthy individuals and people with pathological conditions. Oocyte activation deficiency is associated with abnormalities in the structure, expression, and location of this enzyme in spermatozoa. Artificial activation of oocytes using ionophores, which is the only therapeutic option currently available for patients with its insufficiency, is being debated, especially in terms of its potential epigenetic effects on the embryo. Therefore, interest towards the development of human recombinant PLCζ as an alternative treatment is understandable. Researchers are currently discussing the possibility of diagnostic and clinical application of this enzyme to overcome male infertility associated with oocyte activation deficiency, as well as general aspects of this pathology. Key words: oocyte activation, infertility, calcium ions, phospholipase C ζ

Clinical aspects of reactive oxygen and nitrogen species

2004 ◽  
Vol 71 ◽  
pp. 121-133 ◽  
Author(s):  
Ascan Warnholtz ◽  
Maria Wendt ◽  
Michael August ◽  
Thomas Münzel
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Risk Factor ◽  
Endothelial Dysfunction ◽  
Vascular Tissue ◽  
Rapid Development ◽  
Reactive Oxygen ◽  
Clinical Aspects ◽  
No Production ◽  
Oxygen Species

Endothelial dysfunction in the setting of cardiovascular risk factors, such as hypercholesterolaemia, hypertension, diabetes mellitus and chronic smoking, as well as in the setting of heart failure, has been shown to be at least partly dependent on the production of reactive oxygen species in endothelial and/or smooth muscle cells and the adventitia, and the subsequent decrease in vascular bioavailability of NO. Superoxide-producing enzymes involved in increased oxidative stress within vascular tissue include NAD(P)H-oxidase, xanthine oxidase and endothelial nitric oxide synthase in an uncoupled state. Recent studies indicate that endothelial dysfunction of peripheral and coronary resistance and conductance vessels represents a strong and independent risk factor for future cardiovascular events. Ways to reduce endothelial dysfunction include risk-factor modification and treatment with substances that have been shown to reduce oxidative stress and, simultaneously, to stimulate endothelial NO production, such as inhibitors of angiotensin-converting enzyme or the statins. In contrast, in conditions where increased production of reactive oxygen species, such as superoxide, in vascular tissue is established, treatment with NO, e.g. via administration of nitroglycerin, results in a rapid development of endothelial dysfunction, which may worsen the prognosis in patients with established coronary artery disease.

Clinical Aspects of the Hepatic Circulation

1965 ◽  
Vol 48 (6) ◽  
pp. 790-804 ◽  
Author(s):  
Carroll M. Leevy
Keyword(s):  
Clinical Aspects ◽  
Hepatic Circulation

Noninvasive Assessment of Coronary Artery Disease – Anatomical versus Functional Imaging and the Marginal Role of Exercise Electrocardiograms

Praxis ◽  
2020 ◽  
Vol 109 (14) ◽  
pp. 1141-1149
Author(s):  
Martina Boscolo Berto ◽  
Dominik C. Benz ◽  
Christoph Gräni
Keyword(s):  
Coronary Artery Disease ◽  
Coronary Artery ◽  
Functional Imaging ◽  
Clinical Aspects ◽  
Industrialized Countries ◽  
Coronary Syndromes ◽  
Pros And Cons ◽  
Noninvasive Assessment ◽  
Artery Disease ◽  
European Society Of Cardiology

Abstract. Coronary artery disease (CAD) is the leading cause of morbidity and mortality in the industrialized countries. Assessment of symptomatic patients with suspected obstructive CAD is a common reason for a clinical visit. Noninvasive anatomical and functional imaging are established tools to rule-in and rule-out CAD, to assess the severity of disease and to determine the potential risk of future cardiovascular events. In this review, we discuss the updated Guidelines from the European Society of Cardiology on Chronic Coronary Syndromes and explore the different imaging modalities used in current clinical practice for the noninvasive assessment of CAD. The pros and cons of each method, especially comparing anatomical and functional testing, are presented. Furthermore we we address the practical clinical aspects in the selection of the optimal noninvasive tests according to clinical need.

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