scholarly journals Hypertension in dogs and cats: Causes and effects

2005 ◽  
Vol 59 (1-2) ◽  
pp. 149-154
Author(s):  
Predrag Stepanovic ◽  
Zorica Stefanovic-Nikolovski
Keyword(s):  
Blood Pressure ◽  
Peripheral Resistance ◽  
Systemic Blood Pressure ◽  
Past Century ◽  
Physiological Control ◽  
Indirect Methods ◽  
The Past ◽  
Large Numbers ◽  
Blockers Of Calcium Channels ◽  
Therapy Of Hypertension

During the nineties of the past century, several authors underscored the necessity of measuring blood pressure during a regular clinical examination of veterinary patients, because hypertension occurs as an accessory symptom in the course of diseased conditions. In addition to blood pressure measurements, most authors believe that it is necessary also to examine intraocular pressure, like in human medicine. Hypertension can be defined as a chronic increase of the systolic and diastolic blood pressure. Systemic blood pressure is proportionate to the heart rate and total peripheral resistance, while physiological control depends on the reninangiotensin system, aldosterone, prostaglandin, adrenergic and neurogenic factors. Some other factors can also have an influence on the measured values of blood pressure (such as age, sex, race, temperament, environment, and, in part, also how and where the pressure measurement was taken). It has been generally accepted in veterinary medicine than an animal can be considered hypertensive if the measured systolic/diastolic pressures are higher than 180/100 mm Hg. Hypertension can be primary (sometimes also defined as essential or idiopathic) when it is a consequence of several factors which include heart, neurological, kidney, endocrine, and metabolic aspects. Hypertension is defined as secondary when it occurs as a consequence of certain chronic disorders (such as hyperthyroidism, hypothyroidism, hyperadrenocorticism, pheochromocytoma, and diabetes mellitus). Blood pressure can be measured in animals using direct or indirect methods. The oscilometric and the ultrasonographic methods are equally used in the world today. Following detailed studies by large numbers of authors, the physiological frameworks of blood pressure in animals have been precisely determined. Different treatments are applied in the therapy of hypertension in animals, such as: restrictive diets, diuretics, a, and (3 blockers, blockers of calcium channels, vasodilators, ACE inhibitors. Hypertension can also be a state that requires emergency treatment, when it is resolved with aggressive therapy.

Control of Blood Pressure and the Distribution of Blood Flow

1991 ◽  
Vol 7 (S1) ◽  
pp. 79-84 ◽  
Author(s):  
Hans T. Versmold
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cardiac Output ◽  
Peripheral Resistance ◽  
Systemic Blood Pressure ◽  
Adrenergic Innervation ◽  
Systemic Blood ◽  
Low Cardiac Output ◽  
Neurohumoral Control ◽  
The Brain

Systemic blood pressure (BP) is the product of cardiac output and total peripheral resistance. Cardiac output is controlled by the heart rate, myocardial contractility, preload, and afterload. Vascular resistance (vascular hindrance × viscosity) is under local autoregulation and general neurohumoral control through sympathetic adrenergic innervation and circulating catecholamines. Sympathetic innovation predominates in organs receivingflowin excess of their metabolic demands (skin, splanchnic organs, kidney), while innervation is poor and autoregulation predominates in the brain and heart. The distribution of blood flow depends on the relative resistances of the organ circulations. During stress (hypoxia, low cardiac output), a raise in adrenergic tone and in circulating catecholamines leads to preferential vasoconstriction in highly innervated organs, so that blood flow is directed to the brain and heart. Catecholamines also control the levels of the vasoconstrictors renin, angiotensin II, and vasopressin. These general principles also apply to the neonate.

Social memory and battle names: Exploring links between travel, memory and the media

2015 ◽  
Vol 16 (3) ◽  
pp. 242-253 ◽  
Author(s):  
Caroline Winter
Keyword(s):  
Social Memory ◽  
Popular Media ◽  
Great War ◽  
Past Century ◽  
The Past ◽  
Large Numbers ◽  
The Media ◽  
The Great War

The profile of five battles fought by Australians in the Great War (1914–1918) was traced over the past century using the frequency by which they were cited in the popular media. The pattern of these frequencies appeared to remain much the same from 1915 until the 1990s with battles involving very large numbers of casualties at Pozières and Passchendaele having a higher media frequency than smaller battles at Fromelles and Villers-Bretonneux. Gallipoli's status as Australia's best known battlefield has been consistent from 1915 until the present day. Over the past decade however, the media frequencies suggest that there has been a re-prioritization in the importance of these five battles. The discovery of lost graves at Fromelles and the introduction of a Dawn Service at Villers-Bretonneux has elevated the importance of these two sites, with the result that tourist visitation to them has also increased.

scholarly journals Cuff-Method Thigh Arterial Occlusion Counteracts Cerebral Hypoperfusion Against the Push–Pull Effect in Humans

2021 ◽  
Vol 12 ◽  
Author(s):  
Changyang Xing ◽  
Yuan Gao ◽  
Xinpei Wang ◽  
Wenjuan Xing ◽  
Yunnan Liu ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
High Performance ◽  
Cerebral Blood Flow Velocity ◽  
Blood Pressure Response ◽  
Peripheral Resistance ◽  
Arterial Occlusion ◽  
Resistance Index ◽  
Systemic Blood Pressure ◽  
Cerebral Hypoperfusion

Exposure to acute transition from negative (−Gz) to positive (+ Gz) gravity significantly impairs cerebral perfusion in pilots of high-performance aircraft during push—pull maneuver. This push—pull effect may raise the risk for loss of vision or consciousness. The aim of the present study was to explore effective countermeasures against cerebral hypoperfusion induced by the push—pull effect. Twenty healthy young volunteers (male, 21 ± 1 year old) were tested during the simulated push–pull maneuver by tilting. A thigh cuff (TC) pressure of 200 mmHg was applied before and during simulated push—pull maneuver (−0.87 to + 1.00 Gz). Beat-to-beat cerebral and systemic hemodynamics were measured continuously. During rapid −Gz to + Gz transition, mean cerebral blood flow velocity (CBFV) was decreased, but to a lesser extent, in the TC bout compared with the control bout (−3.1 ± 4.9 vs. −7.8 ± 4.4 cm/s, P < 0.001). Similarly, brain-level mean blood pressure showed smaller reduction in the TC bout than in the control bout (−46 ± 12 vs. −61 ± 13 mmHg, P < 0.001). The systolic CBFV was lower but diastolic CBFV was higher in the TC bout. The systemic blood pressure response was blunted in the TC bout, along with similar heart rate increase, smaller decrease, and earlier recovery of total peripheral resistance index than control during the gravitational transition. These data demonstrated that restricting thigh blood flow can effectively mitigate the transient cerebral hypoperfusion induced by rapid shift from −Gz to + Gz, characterized by remarkable improvement of cerebral diastolic flow.

Lessons about Learning as a Community

2001 ◽  
Author(s):  
Barbara Rogoff ◽  
Leslee Bartlett
Keyword(s):  
Human Learning ◽  
Daily Activities ◽  
Past Century ◽  
The Past ◽  
Children’S Learning ◽  
Large Numbers ◽  
History Of ◽  
Children's Interests ◽  
Formal School ◽  
Children's Learning

Throughout the past century, U.S. parents, scholars, and educators have debated how to help children learn in schools. This book contributes to the discussion by presenting ideas about how children can learn in a community organized to foster their learning. Our ideas stem from participation in an innovative public school that prioritizes instruction that builds on children’s interests in a collaborative way, where learning activities are planned by children as well as adults, and where parents and teachers not only foster children’s learning but also learn from their involvement with the children. Despite some notable experiments to make changes in formal school instruction, the routines of U.S. schooling have remained quite stable across the past century, with the following characteristics: . . . • Being compulsory for all children . . . . . . • Segregating children from the daily activities of the adults in their community . . . . . . • Isolating several dozen children with a single adult charged with their instruction . . . . . . • Grouping children according to their birthdates to provide large numbers of children with standard instruction in a step-by-step fashion . . . . . . • Isolating skills from their integrated use in productive activities . . . . . . • Attempting to motivate children by grading their performance . . . The familiarity of these aspects of schooling have led many adults to assume that these characteristics are necessary to learning in general. It is natural to take for granted the accustomed ways of doing things. As people continue to search for arrangements that communities can use to foster the next generation’s development, efforts to try different arrangements to aid children’s learning are very important, especially as times change. The particular form taken by U.S. schools in the 1900s is only one configuration of possible solutions to the question of how to help children learn the skills that they will need as they mature. Formal, compulsory schooling is a brief experiment in the history of human learning.

Central Blood Pressure and Heart Output in Surfaced and Submerged Frogs

1965 ◽  
Vol 42 (2) ◽  
pp. 339-357
Author(s):  
G. SHELTON ◽  
D. R. JONES
Keyword(s):  
Blood Pressure ◽  
Rana Pipiens ◽  
Pulse Wave ◽  
Diastolic Pressure ◽  
Peripheral Resistance ◽  
Systolic Pressure ◽  
Systemic Blood Pressure ◽  
Minute Volume ◽  
Central Blood Pressure ◽  
Systemic Blood

1. The systemic blood pressure of Rana pipiens and R. temporaria is slightly higher than the pulmocutaneous pressure at systole and much higher at diastole. The pulses differ in shape and a conus component can be seen in the systemic wave. 2. Submersion of the animal causes a fall in systolic pressure in both arches, the diastolic pressure remaining relatively constant. The shape of the pulse wave changes, the conus component being accentuated and visible in recordings from both arches. 3. Heart rate and stroke volume fall during submersion so that after 30 min. under water the minute volume may be 20-50% of the value at the surface. The heart becomes increasingly full of blood. 4. The differences in systemic and pulmocutaneous pressures are explained in terms of resistance, compliance and flow in lung and body circuits. The same general relationships persist during submersion but selective increases in peripheral resistance must occur to maintain the central blood pressure in face of falling heart output.

scholarly journals The pharmacology of antihypertensive medicines

2020 ◽  
Vol 19 (2) ◽  
pp. 75-88
Author(s):  
V. A. Tsyrlin
Keyword(s):  
Blood Pressure ◽  
Vascular Tone ◽  
Peripheral Resistance ◽  
Blood Pressure Level ◽  
Circulatory System ◽  
Systemic Blood Pressure ◽  
Minute Volume ◽  
System Functioning ◽  
Regulation Mechanisms ◽  
Human Cardiovascular System

The lecture presents contemporary view on the human cardiovascular system organization. The mechanisms determining the systemic blood pressure level are shown; the factors regulating minute volume of blood circulation and peripheral resistance to blood flow are described. The mechanisms of neurogenic and basal vascular tone are noted, the role of humoral and endothelial regulation mechanisms of the artery lumen s is indicated. Based on the recent evidences of the circulatory system functioning, we gave a description of the main medicinal compounds used in clinical practice to decrease blood pressure. The pharmacological drugs decreasing neurogenic vascular tone and inhibiting basal vascular tone are indicated. The data of drug action, its pharmacodynamics and basic principles of combined use for the rational treatment of hypertension are presented. The lecture may be interesting to physiologists, pharmacologists, cardiologists, therapists, medical students and clinical residents.

Cardiovascular response to acute hypocapnia due to overbreathing

1964 ◽  
Vol 206 (5) ◽  
pp. 1025-1030 ◽  
Author(s):  
Robert C. Little ◽  
Charles W. Smith
Keyword(s):  
Blood Pressure ◽  
Cardiac Output ◽  
Vascular Resistance ◽  
Total Peripheral Resistance ◽  
Artificial Respiration ◽  
Cardiovascular Response ◽  
Peripheral Resistance ◽  
Systemic Blood Pressure ◽  
Fixed Rate ◽  
Essential Change

Anesthetized dogs were maintained by artificial respiration at a fixed rate and depth. The composition of inspired CO2 was varied while O2 content was maintained at control levels. Cardiac output was measured by the indicator-dilution technique. Acute reduction of end-expiratory CO2 levels below the normal value caused a decrease in blood pressure, pulse pressure, stroke volume, and cardiac output, no essential change in heart rate and an increase in total peripheral resistance. Mean systemic blood pressure and net vascular resistance were less with hypocapnia than they were at the same cardiac output at normal CO2 levels. However, the over-all vascular resistance was greater with hypocapnia than it was in the same animal at normal CO2 levels and control output values. Analysis of these data leads to the conclusion that the hypocapnia produced by overbreathing causes some degree of net vasodilation. The hypotension associated with hyperventilation appears to result in these experiments from the drop in cardiac output and to a lesser degree the relatively less than normal compensatory increase in total peripheral resistance.

scholarly journals Regulation of Blood Pressure and Salt Homeostasis by Endothelin

2011 ◽  
Vol 91 (1) ◽  
pp. 1-77 ◽  
Author(s):  
Donald E. Kohan ◽  
Noreen F. Rossi ◽  
Edward W. Inscho ◽  
David M. Pollock
Keyword(s):  
Blood Pressure ◽  
Extracellular Fluid ◽  
Systemic Blood Pressure ◽  
Physiological Control ◽  
Water Excretion ◽  
Venous Capacitance ◽  
Physiological Regulation ◽  
Regulation Of Blood Pressure ◽  
Salt Homeostasis

Endothelin (ET) peptides and their receptors are intimately involved in the physiological control of systemic blood pressure and body Na homeostasis, exerting these effects through alterations in a host of circulating and local factors. Hormonal systems affected by ET include natriuretic peptides, aldosterone, catecholamines, and angiotensin. ET also directly regulates cardiac output, central and peripheral nervous system activity, renal Na and water excretion, systemic vascular resistance, and venous capacitance. ET regulation of these systems is often complex, sometimes involving opposing actions depending on which receptor isoform is activated, which cells are affected, and what other prevailing factors exist. A detailed understanding of this system is important; disordered regulation of the ET system is strongly associated with hypertension and dysregulated extracellular fluid volume homeostasis. In addition, ET receptor antagonists are being increasingly used for the treatment of a variety of diseases; while demonstrating benefit, these agents also have adverse effects on fluid retention that may substantially limit their clinical utility. This review provides a detailed analysis of how the ET system is involved in the control of blood pressure and Na homeostasis, focusing primarily on physiological regulation with some discussion of the role of the ET system in hypertension.

Neural regulation of blood pressure in rainbow trout (Salmo gairdneri)

1978 ◽  
Vol 56 (8) ◽  
pp. 1678-1683 ◽  
Author(s):  
D. G. Smith
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Rainbow Trout ◽  
Peripheral Resistance ◽  
Systemic Blood Pressure ◽  
Salmo Gairdneri ◽  
Exercise Tachycardia ◽  
Aortic Blood Pressure ◽  
And Control ◽  
Selective Increase

Mean dorsal aortic blood pressure (Pda) and heart rate were measured in free-swimming rainbow trout (Salmo gairdneri). The fish were swum in a water tunnel at 0.5 body lengths/s (control) and were exercised at 45-min intervals by a 5-min period of rapid swimming at 2 body lengths/s.Control Pda was 4.0 ± 0.11 kPa and control heart rate was 56 ± 2.1 beats/min. During rapid swimming Pda and heart rate increased by 15 and 13% respectively. α-Receptor blockade with phentolamine (2 mg/kg) or adrenergic transmitter release blockade with bretylium (10 mg/kg) prevented the exercise hypertension and converted it to a decrease of 5% (phentolamine) or 18% (bretylium). Exercise tachycardia was reduced slightly by each compound. Phentolamine decreased the control Pda by 5%. Acute bretylium treatment increased Pda by 39% but Pda in fish treated chronically with bretylium was 30% below control and decreased by a further 6% during rapid swimming. The acute effects of these and other antihypertensive compounds are discussed. It is concluded that systemic blood pressure in trout is controlled by tonically active adrenergic nerves acting on systemic vessels via α-adrenoreceptors. These nerves produce a selective increase in peripheral resistance during rapid swimming.

The zoonotic potential of bat-borne coronaviruses

2020 ◽  
Vol 4 (4) ◽  
pp. 365-381
Author(s):  
Ny Anjara Fifi Ravelomanantsoa ◽  
Sarah Guth ◽  
Angelo Andrianiaina ◽  
Santino Andry ◽  
Anecia Gentles ◽  
...  
Keyword(s):  
Genetic Material ◽  
Field Research ◽  
Sympatric Species ◽  
Animal Origin ◽  
Mammalian Host ◽  
Past Century ◽  
The Past ◽  
Novel Host ◽  
Horseshoe Bat ◽  
Human Infections

Seven zoonoses — human infections of animal origin — have emerged from the Coronaviridae family in the past century, including three viruses responsible for significant human mortality (SARS-CoV, MERS-CoV, and SARS-CoV-2) in the past twenty years alone. These three viruses, in addition to two older CoV zoonoses (HCoV-229E and HCoV-NL63) are believed to be originally derived from wild bat reservoir species. We review the molecular biology of the bat-derived Alpha- and Betacoronavirus genera, highlighting features that contribute to their potential for cross-species emergence, including the use of well-conserved mammalian host cell machinery for cell entry and a unique capacity for adaptation to novel host environments after host switching. The adaptive capacity of coronaviruses largely results from their large genomes, which reduce the risk of deleterious mutational errors and facilitate range-expanding recombination events by offering heightened redundancy in essential genetic material. Large CoV genomes are made possible by the unique proofreading capacity encoded for their RNA-dependent polymerase. We find that bat-borne SARS-related coronaviruses in the subgenus Sarbecovirus, the source clade for SARS-CoV and SARS-CoV-2, present a particularly poignant pandemic threat, due to the extraordinary viral genetic diversity represented among several sympatric species of their horseshoe bat hosts. To date, Sarbecovirus surveillance has been almost entirely restricted to China. More vigorous field research efforts tracking the circulation of Sarbecoviruses specifically and Betacoronaviruses more generally is needed across a broader global range if we are to avoid future repeats of the COVID-19 pandemic.

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