circulatory model
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Author(s):  
Parham Mortazavi ◽  
Mohammad Hossein Hosseinzadeh ◽  
Mohammad Ali Ebrahimzadeh

Introduction: Hypoxia defines as a condition in which body tissues do not take sufficient oxygen supply. Chronic hypoxia has various medical consequences. Recently, the role of hypoxia in the progression of COVID-19 disease has been proven. Ginkgo biloba is a valuable plant from more than 2000 years ago. Ginkgo has antioxidant activity and exhibits good scavenging activity on the free radicals therefore, it is considered helpful in treating diseases associated with the generation of free radicals, including chronic inflammation, cerebral infarction, ischemic heart disease, and aging.Material and Methods: In this study, anti-hypoxic activities of G. biloba methanolic leaf extract have been determined against hypoxia-induced lethality in mice to understand its usefulness in treating ischemia.Results: The extract showed weak activity in asphyctic model. At 125 mg/kg, it significantly delayed the time of death compared to the control group (p<0.05) but did not show any activities in haemic or circulatory hypoxia tests even at a higher tested dose, 250 mg/kg. Although, at this dose, extract prolonged the survival time more than 1 minute in circulatory model, but this increase was not statistically significant.Conclusion: In conclusion, results from this study showed that extract has weak anti-hypoxic effects in the treatment of hypoxia.  


Author(s):  
Razieh Shahnazi ◽  
Mohammad Ali Ebrahimzadeh

Vicia genus has 45 species in Iran. Many protective and biological activities have been reported from these species. In spite of many works, nothing is known about protective effect of V. cracca against hypoxia conditions. In this study, protective effects of V. cracca extract against hypoxia-induced lethality in mice were evaluated by three experimental models of hypoxia, asphyctic, haemic and circulatory. Statistically significant protective activities were observed in some doses of extract in three models. Antihypoxic activity was especially pronounced in asphyctic model. Extract at 200 mg/kg prolonged survival time (27.37 ± 4.0 min) but was not comparable with that of phenytoin (39.80 ± 1.92). At 100 mg/kg it also prolonged survival time (24.76 ± 3.7 min) which was so higher than control group. In haemic model, V. cracca extract significantly and dose dependently prolonged survival time as compared to control group. At 200 mg/kg, extract was being capable of keeping the mice alive for 15.38 ± 1.93 min. It was also effective in circulatory model. V. cracca extract at 200 mg/kg prolonged survival time (16.84 ± 1.47 min) that was statistically significant as compared to control group (13.14 ± 0.51 min). V. cracca extract showed a very good protective effect against the hypoxia in some models. Specifically, they produced significant and dose-dependent effect on the model of asphytic and haemic hypoxia. The presence of polyphenols in this plant may be a proposal mechanism for reported antihypoxic activities of this plant.


2018 ◽  
Vol 8 (7) ◽  
pp. 1017 ◽  
Author(s):  
Andrzej Polanczyk ◽  
Markus Klinger ◽  
Josif Nanobachvili ◽  
Ihor Huk ◽  
Christoph Neumayer
Keyword(s):  

2018 ◽  
Vol 51 (2) ◽  
pp. 181-203 ◽  
Author(s):  
MICHAEL J. NEUSS

AbstractWilliam Harvey's famous quantitative argument fromDe motu cordis(1628) about the circulation of blood explained how a small amount of blood could recirculate and nourish the entire body, upending the Galenic conception of the blood's motion. This paper argues that the quantitative argument drew on the calculative and rhetorical skills of merchants, including Harvey's own brothers. Modern translations ofDe motu cordisobscure the language of accountancy that Harvey himself used. Like a merchant accounting for credits and debits, intake and output, goods and moneys, Harvey treated venous and arterial blood as essentially commensurate, quantifiable and fungible. For Harvey, the circulation (and recirculation) of blood was an arithmetical necessity. The development of Harvey's circulatory model followed shifts in the epistemic value of mercantile forms of knowledge, including accounting and arithmetic, also drawing on an Aristotelian language of reciprocity and balance that Harvey shared with mercantile advisers to the royal court. This paper places Harvey's calculations in a previously underappreciated context of economic crisis, whose debates focused largely on questions of circulation.


2017 ◽  
Vol 27 (3) ◽  
pp. 19-24
Author(s):  
Drew D. Lewis

Abstract The osteopathic profession has long emphasized the importance of improving homeostasis and overall health through the use of osteopathic manipulative treatment (OMT). The respiratory-circulatory model seeks to achieve these goals by resolving somatic dysfunctions (SD) that may restrict venous and lymphatic return. One of the most significant somatic dysfunctions to address in this model is the thoracic inlet. Despite the emphasis on this somatic dysfunction, classic treatment approaches of the thoracic inlet remain some of the most challenging corrections. In this article, an approach to somatic dysfunction of the thoracic inlet (SDTI) with a new application of Still technique principles is presented. This technique offers a safe, efficient, and effective treatment approach for patients who may present with substantial comorbidities. Considerations for difficult to correct SDTI are discussed. In addition, a more global approach is presented—with an awareness of the dynamic structural relationships and functionality of the region—to treat SDTI with enhanced success.


2015 ◽  
Vol 63 (3) ◽  
pp. 605-612 ◽  
Author(s):  
M. Kozarski ◽  
P. Suwalski ◽  
K. Zieliński ◽  
K. Górczyńska ◽  
B. Szafron ◽  
...  

Abstract In most cases of diseased heart valves, they can be repaired or replaced with biological or mechanical prostheses. Biological prostheses seem to be safer than mechanical ones and are applied with good clinical outcomes. Their disadvantage, when compared with mechanical valves, is durability. In the development and application of mechanical and biological heart valves, a significant role can be played by a Hybrid (Hydro-Numerical) Circulatory Model. The aim of this paper is to demonstrate the opportunities created by the hybrid model for investigations of mechanical heart valves and their computer models under conditions similar to those of the circulatory system. A diode-resistor numerical valve model and three different design mechanical aortic valves were tested. To perform their investigations, computer applications were developed under RT LabView to be run on a PC. Static and dynamic characteristics of the valves were measured and registered - pressure in the numerical time-varying elastance left ventricle (pLV), in the aorta (pas) and flow (f), proving, among other factors, that 1) time delay of pas with respect to pLV is mainly related to the valve’s opening time, and 2) the valves of substantially different designs tested under identical hydrodynamic conditions reveal nearly the same dynamic performance.


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