scholarly journals The Variation Trend of the Human Body’s Susceptibility to SARS-CoV-2 over Time

2020 ◽  
Author(s):  
Bing Luo
Keyword(s):  
Human Body ◽  
Blood Circulation ◽  
Viral Infections ◽  
Venous Blood ◽  
Systemic Circulation ◽  
Venous Reflux ◽  
Blood Flows ◽  
Arterial Blood ◽  
The Earth ◽  
Over Time

In blood circulation (systemic circulation), the order of blood circulation is that arterial blood flows into capillaries only after venous blood refluxes. The human body controls the flow of arterial blood into capillaries by controlling the flow of venous blood. The refluxing power of venous blood changes with the rotation and revolution of the earth, and leads to changes in arterial blood obtained by cells, tissues and organs. If the refluxing power of venous blood of the lungs has a problem, the actual amount of blood obtained by the lungs will be less than the amount of blood distributed to the lungs by the human body (supplying the lungs with nutrients and oxygen they need), and what Pasteur called “the terrain” (There is a paragraph in Seasons of Life: “On his deathbed, Louis Pasteur, the founder of the germ theory of disease, allegedly said, ‘the germ is nothing, the terrain is everything’.”) will form in the lungs. The severity of problems induced by the intensity of venous reflux changes with time, leading to the variation of lung’s susceptibility to viral infections with time.

The Generation of Kinins in the Blood of Dogs during Hypotension Due to Haemorrhage

1970 ◽  
Vol 39 (3) ◽  
pp. 349-365 ◽  
Author(s):  
H. E. Berry ◽  
J. G. Collier ◽  
J. R. Vane
Keyword(s):  
Blood Pressure ◽  
Time Course ◽  
Venous Pressure ◽  
Venous Blood ◽  
Systemic Circulation ◽  
Substantial Effect ◽  
Mixed Venous Blood ◽  
Shed Blood ◽  
Arterial Blood ◽  
Organ Technique

1. Circulating kinins were detected and continuously assayed during hypotension due to haemorrhage in dogs, using the blood-bathed organ technique and isolated strips of cat jejunum as the assay tissue. 2. In arterial blood kinin concentrations of 1–5 ng/ml were attained after a hypotension of 35–65 mmHg had been maintained for 10–190 min. When portal venous blood was simultaneously assayed kinins appeared earlier and in concentrations 1–2 ng/ml higher than in arterial blood. No differences in time course of kinin generation or in concentration were found when mixed venous blood and arterial blood were compared. In those instances in which the blood pressure was restored to normal by returning the shed blood, kinin formation stopped. 3. Kinin generation was due to the presence in the circulation of a kinin-forming enzyme, such as kallikrein. When kallikrein was infused into the portal vein, it was partially inactivated by the liver. 4. Prolonged intravenous infusions of kallikrein (20–60 mu kg−1 min−1) generated kinins in the circulation in concentrations (1–5 ng/ml) which were well maintained throughout the infusion, demonstrating that kinin generation is not limited by depletion of the precursor kininogen; nevertheless, the effects of kallikrein infusions on the blood pressure and central venous pressure waned. 5. It is concluded that in hypotension due to haemorrhage, an active kallikrein appears in the portal circulation. Delay in the appearance of kallikrein in the systemic circulation may be due to the kallikrein inactivating mechanism of the liver. This inactivating mechanism may fail during shock. Kinins are generated in amounts sufficient to have a substantial effect on the circulation and an influence on the course of events in shock.

scholarly journals Megakaryocytes in the Pulmonary Circulation

Blood ◽  
1963 ◽  
Vol 22 (1) ◽  
pp. 82-87 ◽  
Author(s):  
T. M. SCHEININ ◽  
A. P. KOIVUNIEMI
Keyword(s):  
Malignant Disease ◽  
Venous Blood ◽  
Systemic Circulation ◽  
Severe Anemia ◽  
Blood Samples ◽  
Direct Observations ◽  
Arterial Blood ◽  
Nonmalignant Disease ◽  
Abundant Cytoplasm ◽  
Pulmonary Arterial

Abstract The streptolysin 0 hemolysis method for isolation of cancer cells in the blood was employed for direct observations of the incidence and some characteristics of circulating megakaryocytes. In a series of 168 patients, circulating megakaryocytes were found in 77 per cent of the blood samples. Each sample contained an average of 1.2 megakaryocytes per ml. of blood. The megakaryocytes were most frequent in pulmonary arterial blood and a number of the cells had an apparently intact abundant cytoplasm. Pulmonary venous blood contained megakaryocytes much less frequently. These were almost always without cytoplasm or with only a narrow rim of it and as a rule small naked nuclei or their fragments were found. Manipulation of lung tissue resulted in an increased amount of megakaryocytes in the pulmonary venous blood. The megakaryocytes in pulmonary and systemic circulation were more numerous in advanced malignant disease than in early cases, and more common in inflammatory disease or severe anemia than in other nonmalignant disease.

In situ isolated perfused and innervated left hemidiaphragm preparation

1989 ◽  
Vol 67 (5) ◽  
pp. 2141-2146 ◽  
Author(s):  
S. N. Hussain ◽  
C. Roussos ◽  
S. Magder
Keyword(s):  
Phrenic Nerve ◽  
Venous Blood ◽  
Blocking Agent ◽  
Systemic Circulation ◽  
Neuromuscular Blocking ◽  
Systemic Injection ◽  
In Situ Preparation ◽  
Arterial Blood ◽  
Left Hemidiaphragm

We developed a vascularly isolated in situ preparation of the left hemidiaphragm in which arterial blood was only provided through the left phrenic artery and the venous blood only drained through the phrenic vein. The costal margins were secured and connected to three force transducers. Muscle shortening was measured by sonomicrometry. The presence of arterial collaterals between the left hemidiaphragm and the systemic circulation was excluded by the systemic injection of a vital dye (Lissamine Green), a neuromuscular blocking agent (succinylcholine), and by the injection of epinephrine. Left phrenic nerve stimulation produced homogeneous shortening and tension. The degree of shortening in the isolated and intact left diaphragm at the same resting length was similar. The preparation was stable for 2 h with less than 10% decline in maximum tension. Two advantages of this preparation are particularly important. 1) Diaphragmatic energetics can be studied independently of systemic factors, and 2) the role of phrenic nerve afferents in the control of breathing and systemic circulation can easily be assessed without activating nonphrenic nerve afferents.

scholarly journals Transport of Prostaglandin F2α Pulses from the Uterus to the Ovary at the Time of Luteolysis in Ruminants Is Regulated by Prostaglandin Transporter-Mediated Mechanisms

Endocrinology ◽  
2010 ◽  
Vol 151 (7) ◽  
pp. 3326-3335 ◽  
Author(s):  
JeHoon Lee ◽  
John A. McCracken ◽  
Sakhila K. Banu ◽  
Royce Rodriguez ◽  
Thamizh K. Nithy ◽  
...  
Keyword(s):  
Protein Expression ◽  
Venous Blood ◽  
Prostaglandin F2α ◽  
Systemic Circulation ◽  
Ovarian Vein ◽  
Ovarian Artery ◽  
Transporter Protein ◽  
Arterial Blood ◽  
Tunica Adventitia ◽  
Tunica Intima

In ruminants, prostaglandin F2α (PGF2α) is the uterine luteolytic hormone. During luteolysis, PGF2α is synthesized and released from the endometrium in a pulsatile pattern. The unique structure of the vascular utero-ovarian plexus (UOP) allows transport of luteolytic PGF2α pulses directly from the uterus to the ovary, thus bypassing the systemic circulation. However, the underlying molecular mechanism is not known. The objective of the present study was to determine a role for PG transporter protein (PGT) in the compartmental transport of PGF2α from uterus to ovary through the UOP at the time of luteolysis using the sheep as a ruminant model. [3H]PGF2α, with or without a PGT inhibitor, was infused into UOP, and PGF2α transport and PGT protein expression were determined. Results indicate that PGT protein is expressed in tunica intima, tunica media, and tunica adventitia of the utero-ovarian vein and the ovarian artery of the UOP, and the expression levels are higher on d 10–15 compared with d 3–6 of the estrous cycle. Pharmacological inhibition of PGT prevented transport of exogenous [3H]PGF2α as well as oxytocin-induced endogenous luteolytic PGF2α pulse up to 80% from uterine venous blood into ovarian arterial blood through the UOP at the time of luteolysis in sheep. Taken together, these results indicate that at the time of luteolysis, transport of PGF2α from uterus to ovary through the UOP is regulated by PGT-mediated mechanisms. These findings also suggest that impaired PGT-mediated transport of PGF2α from the utero-ovarian vein into the ovarian artery could adversely influence luteolysis and thus affect fertility in ruminants.

scholarly journals Effect of Electrical Stimulation on Blood Flow in Calf Muscles in Different Body Positions

2018 ◽  
Vol 1 (96) ◽  
Author(s):  
Julius Dovydaitis ◽  
Albinas Grūnovas
Keyword(s):  
Blood Flow ◽  
Body Position ◽  
Venous Blood ◽  
The Body ◽  
Arterial Blood Flow ◽  
Reserve Capacity ◽  
Horizontal Position ◽  
Blood Flows ◽  
Arterial Blood ◽  
Electrical Muscle

Background.  In  most  studies  on  cardiovascular  system,  testing  of  subjects  was  performed  in  a  horizontal position. With the change of the body position, certain functional changes occur in the cardiovascular system. The aim of this study was to analyze the effect of electrical muscle stimulation (EMS) on arterial and venous blood flows.Methods. Eighteen athletes aged 19–23 performed two sessions of tests in horizontal and sitting positions. Changes in arterial and venous blood flows were recorded before and after EMS. In each session two occlusions were performed. In the horizontal position, the initial occlusion pressure of 20 mmHg was applied and as the balance in arterial and venous blood flow rates was reached, the additional pressure of 20 mmHg (40  mmHg in total). In the sitting position, the occlusion pressure of 40 and 20 mmHg was applied respectively (60 mmHg in total). In both sessions EMS was performed using the electrical stimulator Mioritm 021.Results. In both horizontal and vertical positions, the effect of EMS on arterial blood flow, venous reserve capacity and venous elasticity was insignificant. Arterial and venous blood flows was affected significantly by the change of the body position. In the sitting position, arterial blood flow was significantly (p < .05) lower compared to the horizontal position. Similar results were recorded in venous reserve capacity.Conclusion.  The  study  suggests  that  blood  flow  in  the  calf  muscles  is  affected  by  the  body  position  and hydrostatic pressure; arterial blood flow increases in the horizontal body position.Keywords:  electrical muscle stimulation (EMS), arterial blood flow, venous reserve capacity, venous elasticity

scholarly journals The discovery of lymphatic system as a turning point in medical knowledge: Aselli, Pecquet and the end of hepatocentrism

2017 ◽  
Vol 2 (2) ◽  
pp. 67-76
Author(s):  
Luca Tonetti
Keyword(s):  
Portal Vein ◽  
Human Body ◽  
Thoracic Duct ◽  
Blood Circulation ◽  
Turning Point ◽  
Lymphatic System ◽  
Venous Blood ◽  
Medical Knowledge ◽  
17Th Century ◽  
The Impact

In this paper, I would like to analyse the impact of the discovery of lymphatic system on the development of the modern conception of human body. The discovery of lymphatics, as that of blood circulation, has in fact questioned important tenets of Galen's anatomo-physiology. Galen defended a 'dualistic conception' of the blood: he distinguished two different systems, the hepatic-venous system and the cardio-arterial one. The liver played a pivotal role because it was believed to transform the chyle received by the portal vein into venous blood. The discovery of lymphatics challenged this view: 17th-century anatomical dissections and experiments, starting with the discovery of milky veins by Gaspare Aselli (1581-1625) and the studies on thoracic duct by Jean Pecquet (1622-1674), irrefutably showed that the chyle does not pour out in the liver and that, consequently, the liver does not produce blood.

Altering blood flow does not reveal differences between nitrogen and helium kinetics in brain or in skeletal miracle in sheep

2015 ◽  
Vol 118 (5) ◽  
pp. 586-594 ◽  
Author(s):  
David J. Doolette ◽  
Richard N. Upton ◽  
Cliff Grant
Keyword(s):  
Blood Flow ◽  
Hind Limb ◽  
Femoral Vein ◽  
Venous Blood ◽  
Compartmental Models ◽  
Arterial Blood Gas ◽  
Blood Flows ◽  
Sagittal Sinus ◽  
Oxygen Breathing ◽  
Arterial Blood

In underwater diving, decompression schedules are based on compartmental models of nitrogen and helium tissue kinetics. However, these models are not based on direct measurements of nitrogen and helium kinetics. In isoflurane-anesthetized sheep, nitrogen and helium kinetics in the hind limb ( n = 5) and brain ( n = 5) were determined during helium-oxygen breathing and after return to nitrogen-oxygen breathing. Nitrogen and helium concentrations in arterial, femoral vein, and sagittal sinus blood samples were determined using headspace gas chromatography, and venous blood flows were monitored continuously using ultrasonic Doppler. The experiment was repeated at different states of hind limb blood flow and cerebral blood flow. Using arterial blood gas concentrations and blood flows as input, parameters and model selection criteria of various compartmental models of hind limb and brain were estimated by fitting to the observed venous gas concentrations. In both the hind limb and brain, nitrogen and helium kinetics were best fit by models with multiexponential kinetics. In the brain, there were no differences in nitrogen and helium kinetics. Hind limb models fit separately to the two gases indicated that nitrogen kinetics were slightly faster than helium, but models with the same kinetics for both gases fit the data well. In the hind limb and brain, the blood:tissue exchange of nitrogen is similar to that of helium. On the basis of these results, it is inappropriate to assign substantially different time constants for nitrogen and helium in all compartments in decompression algorithms.

Cardiovascular changes during spontaneous micturition in conscious cats

1979 ◽  
Vol 237 (2) ◽  
pp. H213-H217
Author(s):  
G. Baccelli ◽  
G. Mancia ◽  
A. Del Bo ◽  
R. Albertini ◽  
A. Zanchetti
Keyword(s):  
Blood Pressure ◽  
Cardiac Output ◽  
Arterial Blood Pressure ◽  
Marked Decrease ◽  
Blood Pressure Level ◽  
Systemic Circulation ◽  
Hemodynamic Changes ◽  
Blood Flows ◽  
Arterial Blood ◽  
Change In Mean

The hemodynamic changes occurring during spontaneous micturition were recorded in conscious cats. Arterial blood pressure was continuously measured by chronically implanted arterial catheter, heart rate (HR) by a cardiotachometer, and cardiac output (CO), superior mesenteric (MF), renal (RF), and external iliac blood flows (IF) by chronically implanted electromagnetic flow probes. Spontaneous micturition was accompanied by little change in mean arterial pressure (-9.7 +/- 0.7%), but by a marked decrease in HR (-49.0 +/- 1.2%) and CO (-28.6 +/- 2.5%), and therefore by a marked decrease in total peripheral conductance (-21.0 +/- 3.5%). Visceral and hindlimb blood flows were markedly reduced during micturition (MF, -34.7 +/- 2.1%; RF, -22.6 +/- 1.5%; and IF, -48.7 +/- 1.5%, respectively) due to a marked reduction in regional conductances in both these areas. The vasomotor changes in the regional circulations were prevented by local sympathectomy. Thus spontaneous micturition is associated with marked changes in cardiac function and systemic circulation. Cardiac output is decreased, but diffuse nervous systemic vasoconstriction compensates for this and provides maintenance of arterial blood pressure level.

Effects of fetal anemia on PO2 difference between uterine venous and umbilical venous blood

1991 ◽  
Vol 260 (1) ◽  
pp. H276-H281
Author(s):  
M. J. Darby ◽  
D. I. Edelstone ◽  
K. Bass ◽  
K. Miller
Keyword(s):  
Venous Blood ◽  
Gas Diffusion ◽  
Fetal Anemia ◽  
O2 Consumption ◽  
Blood Flows ◽  
Umbilical Blood ◽  
Arterial Blood ◽  
Pregnant Sheep ◽  
Functional Equivalent ◽  
Made In

In the fetus, the functional equivalent of the alveolar-arterial blood PO2 difference is the uterine venous-umbilical venous blood PO2 difference. Generally, factors that affect one of the venous blood PO2s produce equivalent effects on the other. We previously showed that fetal anemia produces increases in umbilical venous blood PO2. To determine whether this increase was associated either with equivalent increases in uterine venous blood PO2 or with reductions in the uterine venous-umbilical venous PO2 difference, we studied eight chronically catheterized pregnant sheep and fetal lambs. Measurements of O2 gas tensions and O2 saturations, uterine and umbilical blood flows, and uterine, fetal, and placental O2 consumptions were made in animals with normal fetal hematocrits and during reductions in fetal hematocrit of 35% (moderate fetal anemia) or 60% (severe fetal anemia). Fetal anemia produced reductions in the uterine venous-umbilical venous blood PO2 difference; in some cases the PO2 difference was less than 2 mmHg (compared with normal values of 20 mmHg). The development of both moderate and severe fetal anemia had no effect on uterine and umbilical blood flows or placental O2 consumption but did reduce total uterine and fetal O2 consumption. These data indicate that fetal anemia induces changes in placental gas transport. These changes may be due to improvements in gas diffusion, reductions in perfusion mismatching, or reductions in vascular shunting. Our data further indicate that placental O2 consumption rate, which is high in normal pregnant sheep, plays no role in the maintenance of the uterine venous-umbilical venous blood PO2 difference in pregnant sheep.

scholarly journals Counter-current transfer in reproductive biology

Reproduction ◽  
2005 ◽  
Vol 129 (1) ◽  
pp. 9-18 ◽  
Author(s):  
N Einer-Jensen ◽  
RHF Hunter
Keyword(s):  
Venous Blood ◽  
Feedback Regulation ◽  
Systemic Circulation ◽  
Reproductive Organs ◽  
General Distribution ◽  
Current Transfer ◽  
Local Cooling ◽  
Arterial Blood ◽  
Local Feedback ◽  
Counter Current

Heat and substances, including gases, steroids and peptide hormones, can pass from venous blood, interstitial fluid and lymph to the arterial blood; the process is called local counter-current transfer. It has been found in various reproductive organs in many animal species and in man: from the testis to the testis and epididymis; from the ovary to the ovary, tube and tubal corner of the uterus; from the tube and uterus to the ovary; from vagina to uterus; and even between brain blood vessels. Local transfer within the ovary has also been found. Local cooling that creates temperature gradients between organs or within an organ is one aspect of the transfer. Physiologically, the transfer also facilitates local feedback regulation of organ function in a process situated between general distribution of hormones through the systemic circulation and paracrine regulation. Counter-current transfer of drugs after local application opens up new possibilities for treatment.

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