Muscle Force Generation and Age: The Role of Sex Hormones

1993 ◽  
pp. 129-141 ◽  
Author(s):  
S. K. Phillips ◽  
J. L. Rowbury ◽  
S. A. Bruce ◽  
R. C. Woledge
Keyword(s):  
Sex Hormones ◽  
Muscle Force ◽  
Force Generation

scholarly journals Regulatory Role of Sex Hormones in Cardiovascular Calcification

2021 ◽  
Vol 22 (9) ◽  
pp. 4620
Author(s):  
Holly J. Woodward ◽  
Dongxing Zhu ◽  
Patrick W. F. Hadoke ◽  
Victoria E. MacRae
Keyword(s):  
Cardiovascular Disease ◽  
Sex Differences ◽  
Sexual Dimorphism ◽  
Aortic Stenosis ◽  
Sex Hormones ◽  
Sex Hormone ◽  
Increased Risk ◽  
Male Sex ◽  
Primary Male

Sex differences in cardiovascular disease (CVD), including aortic stenosis, atherosclerosis and cardiovascular calcification, are well documented. High levels of testosterone, the primary male sex hormone, are associated with increased risk of cardiovascular calcification, whilst estrogen, the primary female sex hormone, is considered cardioprotective. Current understanding of sexual dimorphism in cardiovascular calcification is still very limited. This review assesses the evidence that the actions of sex hormones influence the development of cardiovascular calcification. We address the current question of whether sex hormones could play a role in the sexual dimorphism seen in cardiovascular calcification, by discussing potential mechanisms of actions of sex hormones and evidence in pre-clinical research. More advanced investigations and understanding of sex hormones in calcification could provide a better translational outcome for those suffering with cardiovascular calcification.

The role of female sex hormones in the development and severity of allergic and non-allergic asthma

2009 ◽  
Vol 39 (10) ◽  
pp. 1477-1481 ◽  
Author(s):  
M. van den Berge ◽  
H. I. Heijink ◽  
A. J. M. van Oosterhout ◽  
D. S. Postma
Keyword(s):  
Allergic Asthma ◽  
Sex Hormones ◽  
Female Sex ◽  
Female Sex Hormones

The effects of estradiol and testosterone on renal tissues oxidative after central injection of angiotensin II in female doca – salt treated rats

2018 ◽  
Vol 37 (3) ◽  
Author(s):  
Marzieh Kafami ◽  
Mahmoud Hosseini ◽  
Saeed Niazmand ◽  
Esmaeil Farrokhi ◽  
Mosa Al-Reza Hajzadeh ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Angiotensin Ii ◽  
Sex Hormones ◽  
Active Oxygen Species ◽  
Oxygen Species ◽  
Research Needs ◽  
Ang Ii ◽  
Detailed Mechanism ◽  
Female Wistar Rats

Abstract Background Although numerous studies have proven that estrogen (Est) has a protective effect on the development of hypertension, more research needs to be done to show its detailed mechanism in a variety of hypertension. The important role of active oxygen species in blood pressure is well defined. We examined whether or not sex hormones change the growth of reactive oxygen species (ROS) ‎in kidneys after central microinjection of angiotensin II (Ang II).‎ Materials and methods Female Wistar rats, 8 weeks old (200 ± 10 g) were used in this study. The animal groups were (1) Sham, (2) Ovariectomy (OVX), (3) Sham-Hypertension (Sham-Hyper), (4) OVX-Hypertension (OVX-Hyper), (5) Sham-Hyper-Est, (6) OVX-Hyper-Est‎;‎ (7) Sham-Hyper-Testosterone (Tst) and (8) OVX-Hyper-Tst. Solutions of 1% NaCl and 0.1 KCl ‎were used and desoxycorticostrone (doca-salt) was injected (45 mg/kg) 3 times a week in Hypertension groups. Estradiol and Tst (2 mg/kg and ‎5 mg/kg‎; daily; subcutaneously) for 4 weeks. Ang II (50 μM, 5 μL) was microinjected by intracerebroventricular ( i.c.v.) infusion and malondialdehyde (MDA) and thiol in the kidneys were measured. Results MDA in the kidneys was increased by Ang II and doca-salt treatments. Both estradiol and Tst decreased the kidney’s MDA. The level of thiol was higher in Hyper ‎groups and reversed after treatment with estradiol and Tst. Conclusions Our findings suggest that central effect of Ang II on blood pressure and kidney ‎disease is accompanied with increased levels of oxidative stress in the kidneys. Indeed sex hormones change the ROS level in the kidneys after central ‎microinjection of Ang II.‎‎

scholarly journals Extraocular Muscles Tension, Tonus, and Proprioception in Infantile Strabismus: Role of the Oculomotor System in the Pathogenesis of Infantile Strabismus—Review of the Literature

Scientifica ◽  
2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Costantino Schiavi
Keyword(s):  
Critical Period ◽  
Muscle Force ◽  
Sensory System ◽  
Oculomotor System ◽  
Extraocular Muscles ◽  
Review Of The Literature ◽  
Eye Muscle ◽  
System A ◽  
Concomitant Strabismus

The role played by the extraocular muscles (EOMs) in the etiology of concomitant infantile strabismus is still debated and it has not yet definitively established if the sensory anomalies in concomitant strabismus are a consequence or a primary cause of the deviation. The commonest theory supposes that most strabismus results from abnormal innervation of the EOMs, but the cause of this dysfunction and its origin, whether central or peripheral, are still unknown. The interaction between sensory factors and innervational factors, that is, esotonus, accommodation, convergence, divergence, and vestibular reflexes in visually immature infants with family predisposition, is suspected to create conditions that prevent binocular alignment from stabilizing and strengthening. Some role in the onset of fixation instability and infantile strabismus could be played by the feedback control of eye movements and by dysfunction of eye muscle proprioception during the critical period of development of the visual sensory system. A possible role in the onset, maintenance, or worsening of the deviation of abnormalities of muscle force which have their clinical equivalent in eye muscle overaction and underaction has been investigated under either isometric or isotonic conditions, and in essence no significant anomalies of muscle force have been found in concomitant strabismus.

Free radicals in hypoxic rat diaphragm contractility: no role for xanthine oxidase

2001 ◽  
Vol 281 (6) ◽  
pp. L1402-L1412 ◽  
Author(s):  
Leo M. A. Heunks ◽  
Herwin A. Machiels ◽  
Ronney de Abreu ◽  
Xiao Ping Zhu ◽  
Henricus F. M. van der Heijden ◽  
...  
Keyword(s):  
Free Radicals ◽  
Xanthine Oxidase ◽  
Power Output ◽  
Harmful Effect ◽  
Force Generation ◽  
Muscle Performance ◽  
Rat Diaphragm ◽  
Shortening Velocity ◽  
Contraction Pattern

Recent evidence indicates that hypoxia enhances the generation of oxidants. Little is known about the role of free radicals in contractility of the rat diaphragm during hypoxia. We hypothesized that antioxidants improve contractility of the hypoxic rat diaphragm and that xanthine oxidase (XO) is an important source of free radicals in the hypoxic diaphragm. The effects of N-acetylcysteine (NAC; 18 mM), Tiron (10 mM), and the XO inhibitor allopurinol (250 μM) were studied on isometric and isotonic force generation during hypoxia (Po 2 ∼7 kPa). NAC and Tiron decreased maximal force generation, slowed the shortening velocity, and decreased the power output. Fatigue rate was decreased in the presence of either NAC or Tiron. Allopurinol did not alter the contractility or fatigability of the diaphragm. During hyperoxia (Po 2 ∼85 kPa), neither NAC nor allopurinol affected the contractility or fatigability of the diaphragm. Thus free radicals play a significant role in diaphragm contractility during hypoxia. Whether antioxidants exert a beneficial or harmful effect on muscle performance depends on the contraction pattern of the muscle. Free radicals generated by XO do not play a role in diaphragm contractility during either hypoxia or hyperoxia.

scholarly journals The role of sex hormones in the development of Th2 immunity in a gender-biased model ofTrichuris murisinfection

2010 ◽  
Vol 40 (2) ◽  
pp. 406-416 ◽  
Author(s):  
Matthew R. Hepworth ◽  
Matthew J. Hardman ◽  
Richard K. Grencis
Keyword(s):  
Sex Hormones ◽  
Th2 Immunity

scholarly journals Thrust Force Generated by Heaving Motion of a Plate: The Role of Vortex-Induced Force

2021 ◽  
Author(s):  
Kazuo Matsuuchi
Keyword(s):  
Vortex Shedding ◽  
Thrust Force ◽  
Unsteady Motion ◽  
Force Generation ◽  
Thrust Coefficient ◽  
Momentum Change ◽  
Vortex Element ◽  
Motion Characteristics ◽  
Vortex Systems

To understand the force acting on birds, insects, and fish, we take heaving motion as a simple example. This motion might deviate from the real one. However, since the mechanism of force generation is the vortex shedding due to the motion of an object, the heaving motion is important for understanding the force generated by unsteady motion. The vortices released from the object are closely related to the motion characteristics. To understand the force acting on an object, information about momentum change is necessary. However, in vortex systems, it is impossible to estimate the usual momentum. Instead of the momentum, the “virtual momentum,” or the impulse, is needed to generate the force. For calculating the virtual momentum, we traced all vortices over a whole period, which was carried out by using the vortex-element method. The force was then calculated based on the information on the vortices. We derived the thrust coefficient as a function of the ratio of the heaving to travelling velocity.

Sign in / Sign up

Export Citation Format

Share Document