Perfusion rates of brain, intestine and heart under conditions of total body perfusion

1961 ◽  
Vol 200 (3) ◽  
pp. 551-556 ◽  
Author(s):  
John A. Johnson ◽  
Vincent Gott ◽  
Frederick Welland
Keyword(s):  
The Body ◽  
Tissue Analysis ◽  
Heart Ventricle ◽  
Perfusion Rate ◽  
Flow Curves ◽  
Local Flow ◽  
Pressure Flow ◽  
Total Body ◽  
The Brain

The perfusion rates of the brain, intestine and heart ventricle were studied under conditions of total body perfusion. The perfusion rates were estimated by using antipyrine and D2O as reference substances. Local flow was determined from arterial curves and tissue analysis. When the total body perfusion rate was varied between 20 and 80 cc/kg/min., it was found at each rate that the perfusion rate of these organs was over three times that of the body as a whole. At the lowest flows these three organs were favored even more. Tables of perfusion rates at various sites in the brain and intestine are given. Pressure-flow curves for the brain, intestine and heart are given.

Hepatic arterial and portal venous pressure-flow relationships in isolated, perfused liver

1962 ◽  
Vol 202 (6) ◽  
pp. 1090-1094 ◽  
Author(s):  
Robert E. Condon ◽  
Niles D. Chapman ◽  
Lloyd M. Nyhus ◽  
Henry N. Harkins
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Portal Vein ◽  
Venous Pressure ◽  
Perfused Liver ◽  
Perfusion Rate ◽  
Flow Curves ◽  
Pressure Flow ◽  
Pressure Axis ◽  
Blood Pressure Responses

Blood pressure responses to alteration in blood flow were studied in the completely isolated, excised liver of the calf during perfusion of the hepatic artery or portal vein. The pressure-flow curves in both of the afferent vessels of the liver are curvilinear, with concavity toward the pressure axis. Resistance increases progressively with increases in perfusion rate; resistance increases are proportionately of greater magnitude than the increases in blood flow demonstrating autoregulation in both hepatic arterial and portal venous systems. The autoregulatory nature of pressure-flow responses is not affected by prolonged perfusion or marked acidosis.

scholarly journals Chemical composition of organs of children who died from malnutrition

1969 ◽  
Vol 23 (4) ◽  
pp. 783-790 ◽  
Author(s):  
G. A. O. Alleyne ◽  
D. Halliday ◽  
J. C. Waterlow ◽  
B. L. Nichols
Keyword(s):  
Magnesium Content ◽  
The Body ◽  
Liver Fat ◽  
Whole Body ◽  
Total Body Potassium ◽  
Malnourished Children ◽  
Body Counting ◽  
Total Body ◽  
Whole Body Counting ◽  
The Brain

1. Chemical analysis was carried out on samples of brain, liver, skeletal muscle, heart and kidney obtained from children who died of malnutrition. Total body potassium was measured before autopsy by the ‘whole body counting’ technique.2. There was a marked increase in liver fat, and the brain contributed a higher percentage of the body-weight in the more severely malnourished children.3. All the organs had approximately the same concentrations of non-collagen nitrogen. The proportion of collagen was highest in muscle.4. All organs were depleted of potassium, but the muscle was most severely affected. Brain potassium as a percentage of total body potassium was higher than normal in the most severely potassium depleted children.5. Measurements of tissue magnesium showed that there was no difference in magnesium content of tissues when expressed in terms of non-collagen nitrogen. When compared with normal values, muscle was magnesium depleted. The potassium to magnesium ratio was lowest in muscle.

scholarly journals Dynamic pressure-flow relationships of brain blood flow in the monkey

1974 ◽  
Vol 41 (5) ◽  
pp. 590-596 ◽  
Author(s):  
Calvin B. Early ◽  
Richard C. Dewey ◽  
Heinz P. Pieper ◽  
William E. Hunt
Keyword(s):  
Dynamic Pressure ◽  
Lag Time ◽  
Brain Blood Flow ◽  
Vasomotor Response ◽  
Vasomotor Tone ◽  
Flow Curves ◽  
Pressure Flow ◽  
Content Type ◽  
Vascular Bed ◽  
The Brain

✓ Pressure-flow data are presented for the brain vascular bed in the rhesus monkey. These data are obtained at fixed levels of vasomotor tone. Resultant flow curves are called the “dynamic pressure-flow relationships” (DPFR). In the experimental model, arterial pressures are oscillated with a sinusoidal pump at frequencies exceeding the vasomotor response lag time. The resultant DPFR curves are discussed. A model is presented to show that changes in vasomotor tone cause a vertical shift of the DPFR. Changes in vascular bed resistance cause a change in the slope of the DPFR (▵P/▵F).

Cerebral hematocrit in normal man

1964 ◽  
Vol 19 (4) ◽  
pp. 571-574 ◽  
Author(s):  
O. Andrée Larsen ◽  
Niels A. Lassen
Keyword(s):  
Cerebral Blood Volume ◽  
Normal Subjects ◽  
The Body ◽  
Large Vessel ◽  
Multiple Blood ◽  
Equilibrium Concentrations ◽  
Normal Man ◽  
Total Body ◽  
Mean Circulation ◽  
The Brain

The cerebral mean circulation times of plasma and erythrocytes and the cerebral hematocrit were determined by injection of I131-labeled albumin and Cr51-labeled erythrocytes into an antecubital vein, drawing multiple blood samples simultaneously from the carotid artery and the internal jugular vein, and calculating the arteriovenous concentration differences. The total body hematocrit was determined from equilibrium concentrations. In ten normal subjects the average cerebral hematocrit was 92.2% of the large vessel hematocrit, this difference being highly significant (P < 0.001). The total body hematocrit averaged 88.6% of the large vessel value and was significantly lower (P < 0.01) than for the brain. As the cerebral vascular bed has protein-tight capillaries, it is concluded that this area contains an extra plasma volume inside the vessel walls. It is suggested that the oft-repeated finding of a body hematocrit of about 90% of the large vessel hematocrit is mainly due to excess intravascular plasma localized to all the minor vessels in the body. cerebral mean circulation time; cerebral blood volume; body hematocrit Submitted on January 6, 1964

STUDIES IN EXPERIMENTAL HYPERTONICITY

PEDIATRICS ◽  
1960 ◽  
Vol 26 (6) ◽  
pp. 925-938
Author(s):  
Juan F. Sotos ◽  
Philip R. Dodge ◽  
Patricia Meara ◽  
Nathan B. Talbot
Keyword(s):  
Clinical Manifestations ◽  
Extracellular Fluid ◽  
Clinical Syndrome ◽  
The Body ◽  
Ion Concentration ◽  
Brain Cells ◽  
Osmotic Gradient ◽  
Intracellular Volume ◽  
Total Body ◽  
The Brain

Hypertonicity of the body fluids was induced in rabbits by the intravenous infusion of different hypertonic solutions (NaCl. NaCl plus NaHCO3, sucrose, mannitol and urea). The results obtained in this study indicate the following. There is no significant correlation between the clinical syndrome or death and values for total body water, total body solutes, total extracellular or intracellular volume, or concentration of sodium or chloride in the plasma. The clinical manifestations and death can occur in the absence of in tracranial hemorrhage. Hypertonicity, by creating an osmotic gradient between extracellular fluid and brain, is the important factor in producing the characteristic clinical syndrome and death, but is not the immediate cause of these abnormalities. The osmolality necessary to produce these alterations was greater in animals infused with urea. Hypertonicity produces these alterations by decreasing water and increasing ion concentration in the brain. The resulting functional impairment of neurones accounts for the clinical and electroencephalographic abnormalities. The increased values of sodium and chloride in the brain reflect an impairment of function of either brain cells, "blood-brain barrier," or both. Acidosis, hyperkalemia and hyerphosphatemia ensue as a result of hypertonicity. Unless death is imminent, all of the abnormalities described are reversible.

Research Recommendations for Applying Vitamin A-Labelled Isotope Dilution Techniques to Improve Human Vitamin A Nutrition

2014 ◽  
Vol 84 (Supplement 1) ◽  
pp. 52-59 ◽  
Author(s):  
Sherry A. Tanumihardjo ◽  
Anura V. Kurpad ◽  
Janet R. Hunt
Keyword(s):  
Public Health ◽  
Vitamin A ◽  
Vitamin A Deficiency ◽  
Human Subjects ◽  
The Body ◽  
Pool Size ◽  
Serum Retinol ◽  
Vitamin A Status ◽  
Status Assessment ◽  
Total Body

The current use of serum retinol concentrations as a measurement of subclinical vitamin A deficiency is unsatisfactory for many reasons. The best technique available for vitamin A status assessment in humans is the measurement of total body pool size. Pool size is measured by the administration of retinol labelled with stable isotopes of carbon or hydrogen that are safe for human subjects, with subsequent measurement of the dilution of the labelled retinol within the body pool. However, the isotope techniques are time-consuming, technically challenging, and relatively expensive. There is also a need to assess different types of tracers and doses, and to establish clear guidelines for the use and interpretation of this method in different populations. Field-friendly improvements are desirable to encourage the application of this technique in developing countries where the need is greatest for monitoring the risk of vitamin A deficiency, the effectiveness of public health interventions, and the potential of hypervitaminosis due to combined supplement and fortification programs. These techniques should be applied to validate other less technical methods of assessing vitamin A deficiency. Another area of public health relevance for this technique is to understand the bioconversion of β-carotene to vitamin A, and its relation to existing vitamin A status, for future dietary diversification programs.

RELAÇÃO VAZÃO x PRESSÃO EM MICROASPERSORES DAN 2001 SOB CONDIÇÃO ADVERSA DE OPERAÇÃO

Irriga ◽  
2003 ◽  
Vol 8 (1) ◽  
pp. 63-68 ◽  
Author(s):  
Marco Antonio Fonseca Conceição ◽  
Rubens Duarte Coelho
Keyword(s):  
Hydraulic Performance ◽  
Sao Paulo ◽  
The Self ◽  
São Paulo ◽  
Flow Curves ◽  
Pressure Flow ◽  
Adverse Condition ◽  
Irrigation Time ◽  
E Mail ◽  
Stable Flow

RELAÇÃO VAZÃO x PRESSÃO EM MICROASPERSORES DAN 2001 SOB CONDIÇÃO ADVERSA DE OPERAÇÃO  Marco Antônio Fonseca ConceiçãoEmbrapa Uva e Vinho, Estação Experimental de Jales, Jales, SP. CP 241. CEP 15700-000.E-mail: [email protected] Duarte CoelhoDepartamento de Engenharia Rural, Escola Superior de Agricultura “Luiz de Queiroz”, Universidade de São Paulo, Piracicaba, SP. CP 09, CEP 13418-900.E-mail: [email protected]  1 RESUMO  Alguns microaspersores possuem membranas que regulam a sua pressão de operação, mantendo a vazão praticamente estável dentro de uma faixa de pressão na rede hidráulica. Operadores de irrigação no campo, muitas vezes com baixo nível de instrução e sem orientação profissional qualificada, visando reduzir problemas de entupimento ou para diminuir o tempo de irrigação, costumam retirar as membranas autocompensantes para aumentar a vazão do emissores, o que pode comprometer o desempenho hidráulico do sistema. Para avaliar o efeito da retirada da membrana  sobre as vazões dos microaspersores, no presente trabalho determinou-se as relações entre pressão e vazão para sete bocais do microaspersor DAN 2001, operando na ausência da membrana autocompensante. As curvas pressão-vazão sem as membranas autocompensantes apresentaram comportamento potencial com expoentes variando entre 0,58 e 0,64. As vazões dos microaspersores sem as membranas aumentaram de forma inversamente proporcional aos diâmetros dos emissores, quando comparadas às vazões nominais com as membranas.  UNITERMOS: Hidráulica, irrigação, microaspersão.  CONCEIÇÃO, M.A.F.; COELHO, R.D. FLOW X PRESSURE RELATIONSHIP FOR DAN 2001 MICROSPRINKLERS UNDER ADVERSE CONDITION  2 ABSTRACT  Many types of microsprinklers have a self-compensating membrane to regulate their pressure, keeping a stable flow. Many producers usually take the membranes off to reduce clogging problems  or irrigation time. This procedure could endanger the system hydraulic performance. To evaluate the effect of taking off the self-compensating membrane from microsprinklers it was determined, in the present work, the pressure-flow relationship for seven Dan 2001 microsprinkler nozzles operating without the membrane. The pressure-flow curves presented a potential behavior with the exponents varying from 0.58 to 0.64. Microsprinkler flows without the membranes increased inversely proportional to the emitter diameters, comparing to the nominal flows using the membranes.  KEYWORDS: Hydraulic, irrigation, microsprinkler.

EXPERIMENTAL ASSESSMENT OF THE NANOPARTICLES TOXICITY OF NICKEL OXIDE IN TWO SIZES IN THE SUBCHRONIC EXPERIMENT

2018 ◽  
pp. 30-35
Author(s):  
M.P. Sutunkova ◽  
B.A. Katsnelson ◽  
L.I. Privalova ◽  
S.N. Solovjeva ◽  
V.B. Gurvich ◽  
...  
Keyword(s):  
Nickel Oxide ◽  
Nervous Activity ◽  
Equal Mass ◽  
The Body ◽  
Subchronic Toxicity ◽  
Physiological Mechanisms ◽  
Nickel Oxide Nanoparticles ◽  
The Relationship ◽  
The Brain ◽  
Nanoparticles Toxicity

We conducted a comparative assessment of the nickel oxide nanoparticles toxicity (NiO) of two sizes (11 and 25 nm) according to a number of indicators of the body state after repeated intraperitoneal injections of these particles suspensions. At equal mass doses, NiO nanoparticles have been found to cause various manifestations of systemic subchronic toxicity with a particularly pronounced effect on liver, kidney function, the body’s antioxidant system, lipid metabolism, white and red blood, redox metabolism, spleen damage, and some disorders of nervous activity allegedly related to the possibility of nickel penetration into the brain from the blood. The relationship between the diameter and toxicity of particles is ambiguous, which may be due to differences in toxicokinetics, which is controlled by both physiological mechanisms and direct penetration of nanoparticles through biological barriers and, finally, unequal solubility.

The musculature and nervous system of the plerocercoid larva of Dibothriorhynchus grossum (Rud.)

Parasitology ◽  
1941 ◽  
Vol 33 (4) ◽  
pp. 373-389 ◽  
Author(s):  
Gwendolen Rees
Keyword(s):  
Nervous System ◽  
Muscle Mass ◽  
Nerve Cells ◽  
The Body ◽  
Lateral Nerve ◽  
Posterior Median ◽  
The Brain ◽  
Ventral Muscle ◽  
Nerve Cords ◽  
Extrinsic Muscles

1. The structure of the proboscides of the larva of Dibothriorhynchus grossum (Rud.) is described. Each proboscis is provided with four sets of extrinsic muscles, and there is an anterior dorso-ventral muscle mass connected to all four proboscides.2. The musculature of the body and scolex is described.3. The nervous system consists of a brain, two lateral nerve cords, two outer and inner anterior nerves on each side, twenty-five pairs of bothridial nerves to each bothridium, four longitudinal bothridial nerves connecting these latter before their entry into the bothridia, four proboscis nerves arising from the brain, and a series of lateral nerves supplying the lateral regions of the body.4. The so-called ganglia contain no nerve cells, these are present only in the posterior median commissure which is therefore the nerve centre.

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