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.

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 Topsy-turvy: turning the counter-current heat exchange of leatherback turtles upside down

2015 ◽  
Vol 11 (10) ◽  
pp. 20150592 ◽  
Author(s):  
John Davenport ◽  
T. Todd Jones ◽  
Thierry M. Work ◽  
George H. Balazs
Keyword(s):  
Heat Exchangers ◽  
Venous Blood ◽  
Vascular Supply ◽  
The Body ◽  
Leatherback Turtles ◽  
The Core ◽  
Arterial Blood ◽  
Hip Muscles ◽  
Counter Current ◽  
Current Heat

Counter-current heat exchangers associated with appendages of endotherms feature bundles of closely applied arteriovenous vessels. The accepted paradigm is that heat from warm arterial blood travelling into the appendage crosses into cool venous blood returning to the body. High core temperature is maintained, but the appendage functions at low temperature. Leatherback turtles have elevated core temperatures in cold seawater and arteriovenous plexuses at the roots of all four limbs. We demonstrate that plexuses of the hindlimbs are situated wholly within the hip musculature, and that, at the distal ends of the plexuses, most blood vessels supply or drain the hip muscles, with little distal vascular supply to, or drainage from the limb blades. Venous blood entering a plexus will therefore be drained from active locomotory muscles that are overlaid by thick blubber when the adults are foraging in cold temperate waters. Plexuses maintain high limb muscle temperature and avoid excessive loss of heat to the core, the reverse of the accepted paradigm. Plexuses protect the core from overheating generated by muscular thermogenesis during nesting.

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.

Parametric Studies on the Three-Layer Microcirculatory Model for Surface Tissue Energy Exchange

1986 ◽  
Vol 108 (1) ◽  
pp. 89-96 ◽  
Author(s):  
Z. Dagan ◽  
S. Weinbaum ◽  
L. M. Jiji
Keyword(s):  
Venous Blood ◽  
Thermal Characteristics ◽  
Tissue Temperature ◽  
Capillary Perfusion ◽  
Metabolic Heat ◽  
Blood Temperature ◽  
Arterial Blood ◽  
Parametric Studies ◽  
Counter Current ◽  
Cutaneous Blood

The new three-layer microvascular mathematical model for surface tissue heat transfer developed in [1, 2], which is based on detailed vascular casts and tissue temperature measurements in the rabbit thigh, is used to investigate the thermal characteristics of surface tissue under a wide variety of physiological conditions. Studies are carried out to examine the effects of vascular configuration, arterial blood supply rate, distribution of capillary perfusion, cutaneous blood circulation and metabolic heat production on the average tissue temperature profile, the local arterial-venous blood temperature difference in the thermally significant counter-current vessels, and surface heat flux.

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.

Cold-induced shivering in men with thermoneutral skin temperatures

1976 ◽  
Vol 41 (2) ◽  
pp. 142-145 ◽  
Author(s):  
A. G. Buguet ◽  
S. D. Livingstone ◽  
L. D. Reed ◽  
R. E. Limmer
Keyword(s):  
Venous Blood ◽  
Electromyographic Activity ◽  
Jugular Veins ◽  
Arterial Blood ◽  
Air Temperatures ◽  
Cold Room ◽  
Warm Blood ◽  
The Common ◽  
Counter Current ◽  
Skin Temperatures

Twenty-two male Caucasians, aged 20–47 yr, were exposed in a cold room to air temperatures of -33 degrees C while lying in sleeping bags for 2 h. Skin and rectal temperatures as well as electromyographic activity of the chin, forearm, and thigh, were recorded. Shivering occurred in all the subjects, even though skin temperatures were maintained between 31 and 33 degrees C. It is suggested that a counter-current heat exchange occurs whereby the warm blood of the common carotid artery is cooled by cool venous blood in the jugular veins. This cooled arterial blood, in irrigating the hypothalamus, causes shivering.

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.

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