scholarly journals Inhibitory Effect of Some Plasma Protein Fractions When Added to Hemostatic Arterial Blood

Blood ◽  
1960 ◽  
Vol 16 (4) ◽  
pp. 1433-1438 ◽  
Author(s):  
W. O. CRUZ ◽  
J. R. MAGALHAES ◽  
L. MEIS
Keyword(s):  
Blood Plasma ◽  
Plasma Protein ◽  
Inhibitory Activity ◽  
Inhibitory Effect ◽  
Blood Biochemical ◽  
Arterial Blood ◽  
Low Concentrations ◽  
Arterial Plasma ◽  
Normal Hemostasis ◽  
Venous Plasma

Abstract Dog arterial and venous plasma and lymph were fractionated by Cohn method 10 and the fractions tested for inhibitory activity when added to normal arterial blood in the dog hind leg preparation adapted for studies on hemostasis. Cohn fraction IV from arterial or venous plasma and from lymph was the only fraction, at low concentrations, able to inhibit the hemostatic ability of normal arterial plasma. Some facts suggest that alpha-lipoproteins are the plasma constituent of fraction IV with inhibitory effect on normal arterial blood. Biochemical changes in blood plasma seem more important or more directly connected with the mechanism of normal hemostasis control than the participation of blood cellular elements.

Evidence for LH-inhibiting activity in ovine peripheral and testicular blood

1990 ◽  
Vol 123 (3) ◽  
pp. 345-352 ◽  
Author(s):  
V. Papapdopoulos ◽  
P. Kamtchouing ◽  
N. Boujrad ◽  
C. Pisselet ◽  
C. Perreau ◽  
...  
Keyword(s):  
Cyclic Amp ◽  
Breeding Season ◽  
Specific Binding ◽  
Apparent Molecular Weight ◽  
Rete Testis ◽  
Arterial Blood ◽  
Inhibiting Factor ◽  
Arterial Plasma ◽  
Species Specific ◽  
Venous Plasma

Abstract. Intracellular cyclic AMP and testosterone productions by purified mature rat Leydig cells were stimulated by oLH (25 μg/l) 18- and 12-fold, respectively, after a 5-h incubation period. The replacement of the incubation medium by charcoal-treated testicular venous plasma (40%, v/v) from adult rams in the breeding season induced an inhibition of cyclic AMP and testosterone productions (82 and 66%, respectively, of oLH-stimulated values). Testicular arterial plasma is less effective than testicular venous plasma, even when it originates from non-breeding season rams; in that case, testicular venous and arterial plasma strongly inhibit testosterone productions (84 and 67%, respectively of oLH-stimulated values), which probably indicates that the inhibitory activity is higher in the non-breeding season. The addition of peripheral plasma leads to a testosterone production equal to 35 and 65% of the oLH-stimulated values, respectively, for ram blood collected in non-breeding and breeding seasons. The same concentration of ovine testicular lymph or rete testis fluid is without significant effect on cyclic AMP production; however, testosterone is slightly decreased by lymph but enhanced by rete testis fluid. Increasing amounts of venous or arterial testicular blood induce a dose-related decrease of the specific binding of labelled hCG in both rat and ram testicular membranes. This inhibiting factor is present in peripheral and testicular blood of either control or hypophysectomized or castrated rams, is a protein in nature, heat-sensitive, and has an apparent molecular weight higher than 10 000 daltons. These results suggest the existence of a control of LH-specific binding to its receptors and of Leydig cell cyclic AMP and testosterone outputs; these activities are not species-specific and are more concentrated in testicular venous than in arterial blood. The origin of this inhibiting factor remains to be determined, since it is not confined to the testis and not of pituitary origin.

Effects of Angiotensin on Plasma Electrolyte Concentrations in Rabbits and in Man

1974 ◽  
Vol 46 (1) ◽  
pp. 19-36
Author(s):  
J. K. Healy ◽  
A. J. Elliott ◽  
L. C. Harrison
Keyword(s):  
Intravenous Infusion ◽  
Pressor Response ◽  
Human Subjects ◽  
Plasma Electrolyte ◽  
Arterial Blood ◽  
Blood Ph ◽  
Plasma Electrolytes ◽  
Normal Man ◽  
Arterial Plasma ◽  
Venous Plasma

1. The effects of an intravenous infusion of angiotensin on plasma electrolytes were examined in normal, adrenalectomized and nephrectomized groups of rabbits and in normal man. Rabbits were given 1 μg kg−1 min−1 and human subjects 0.008–0.030 μg kg−1 min−1 of angiotensin. 2. In normal rabbits, angiotensin increased arterial and venous plasma K within 2 min by 0.8 and 0.4 mmol l−1 respectively, some hyperkalaemia persisting for 30–60 min. After 60 min arterial plasma Na decreased by 3.8 mmol l−1 and Cl by 2.4 mmol l−1. Arterial blood pH increased 0.04 units after 15 min, and arterial plasma Mg and Ca rose slightly after 2 min. Pressor response was 20–28 mmHg. 3. In adrenalectomized and nephrectomized rabbits, arterial plasma K rose within 2 min by 2.6 and 3.8 mmol l−1 respectively. Arterial plasma Na fell after 60 min in both groups, and also after 2 min in nephrectomized animals. Venous plasma K and Na showed similar although less marked changes. Changes in plasma Mg, Ca and blood pH were not significant. Pressor response in both groups exceeded that in normal rabbits. 4. In man, a sustained rise of 0.2–0.3 mmol 1-1 occurred in arterial plasma K during angiotensin infusion. Arterial blood pH rose 0.01 units after 15 min. Pressor response was 12–15 mmHg. 5. It was concluded that plasma electrolyte levels may change during angiotensin administration in rabbits and man, and that these changes may influence interpretation of physiological actions of angiotensin.

scholarly journals NATURE OF FLUIDS WHICH FUNCTIONALLY DISTEND THE KIDNEY

1956 ◽  
Vol 104 (1) ◽  
pp. 25-40 ◽  
Author(s):  
H. G. Swann ◽  
Luis Valdivia ◽  
A. A. Ormsby ◽  
W. T. Witt
Keyword(s):  
Plasma Protein ◽  
Interstitial Fluid ◽  
Venous Blood ◽  
Extracellular Fluid ◽  
Arterial Occlusion ◽  
Free Fluid ◽  
Arterial Blood ◽  
A Cell ◽  
Composite Mixture ◽  
Venous Plasma

The nature of the fluid draining from the kidney, after its artery was occluded, was investigated. Samples of systemic arterial blood, renal venous blood and urine were also analyzed. It was found that the fluid draining from the kidney after occlusion is a mixture of vascular blood and another fluid designated as "diluting fluid," each contributing half to the composite mixture. In volume the mixture is 26 per cent of the functionally distended kidney. With the assumption that the renal extracellular fluid can be considered a simple mixture of blood plasma and a cell-free fluid, the composition of the "diluting fluid" was deduced from the known compositions of vascular blood and total fluid draining. The ratios of its content in a given substance to that in systemic (or renal venous) plasma are: for Na and Ca, 1.0; K, 1.5; Cl, 1.2; PO4, 2.0; urea, 1.8; plasma protein, 0.3; albumin, 0.4; glucose, 0.4, and osmolarity, 1.2. The fluid bears little or no relation to urine, especially since the urine varied considerably between individual dogs whereas the "diluting fluid" was relatively constant in composition. It was also found that the hematocrit of the fluid draining after arterial occlusion progressively decreased as it flowed out, until the last portion contained only 5 per cent red cells. It is concluded that since renal lymph has approximately the same composition in protein, urea, glucose, and inulin as does "diluting fluid," the latter is, in all probability, renal interstitial fluid. Under the conditions of the experiment, it drains out of the kidney slowly relative to blood drainage. It is large in volume, particularly when compared with the capillaries that nourish it. Its high protein content explains the observation that the kidney is apparently naturally distended with a fluid disproportionately rich in plasma protein.

The Release of Renin into the Renal Circulation of the Anaesthetized Dog

1970 ◽  
Vol 38 (2) ◽  
pp. 157-174 ◽  
Author(s):  
K. F. Hosie ◽  
J. J. Brown ◽  
A. M. Harper ◽  
A. F. Lever ◽  
R. F. MacAdam ◽  
...  
Keyword(s):  
Blood Flow ◽  
Renal Blood Flow ◽  
Plasma Renin ◽  
Renin Release ◽  
Concentration Difference ◽  
Plasma Renin Concentration ◽  
Renal Lymph ◽  
Arterial Blood ◽  
Arterial Plasma ◽  
Venous Plasma

1. In anaesthetized dogs the rate at which renin was released into the circulation of the right and left kidneys was estimated from renal blood flow, haematocrit, and the V-A renin concentration difference across the kidney. Renin was also measured in samples of renal lymph collected at the same time. 2. The effect on renin release of reducing blood flow in one kidney was studied. For all observations (control and experimental), renal venous plasma renin concentration (RVR) was directly related to arterial plasma renin concentration and to renin release; RVR was inversely related to renal plasma flow. 3. The concentration of renin in renal lymph was considerably higher than that in renal venous plasma taken at the same time. Arterial plasma renin concentration was directly related to the sum of the rates at which renin was released from the two kidneys. 4. Clamping the renal artery of one kidney for 1 hr led to a marked reduction of renal blood flow, to a marked increase in RVR and to a variable change in renin release. Removal of the clamp was followed by increased renin release and by reversal of a previously positive V-A renin difference in the control kidney. 5. On several other occasions negative V-A renin differences were observed. That is, more renin appeared to enter the kidney in arterial blood than left in the renal vein.

In Vitro Effects of Ethanol on Rabbit Platelet Aggregation, Secretion of Granule Contents, and Cyclic AMP Levels in the Presence of Prostacyclin

1989 ◽  
Vol 61 (02) ◽  
pp. 254-258 ◽  
Author(s):  
Margaret L Rand ◽  
Peter L Gross ◽  
Donna M Jakowec ◽  
Marian A Packham ◽  
J Fraser Mustard
Keyword(s):  
Cyclic Amp ◽  
Inhibitory Effect ◽  
Rabbit Platelet ◽  
Inhibitory Effects ◽  
Low Concentrations ◽  
Rabbit Platelets ◽  
High Concentrations ◽  
In Vitro Effects ◽  
Aggregation Of Platelets

SummaryEthanol, at physiologically tolerable concentrations, inhibits platelet responses to low concentrations of collagen or thrombin, but does not inhibit responses of washed rabbit platelets stimulated with high concentrations of ADP, collagen, or thrombin. However, when platelet responses to high concentrations of collagen or thrombin had been partially inhibited by prostacyclin (PGI2), ethanol had additional inhibitory effects on aggregation and secretion. These effects were also observed with aspirin- treated platelets stimulated with thrombin. Ethanol had no further inhibitory effect on aggregation of platelets stimulated with ADP, or the combination of ADP and epinephrine. Thus, the inhibitory effects of ethanol on platelet responses in the presence of PGI2 were very similar to its inhibitory effects in the absence of PGI2, when platelets were stimulated with lower concentrations of collagen or thrombin. Ethanol did not appear to exert its inhibitory effects by increasing cyclic AMP above basal levels and the additional inhibitory effects of ethanol in the presence of PGI2 did not appear to be brought about by further increases in platelet cyclic AMP levels.

Measurement of the Platelet Response to Laser- induced Microvascular Injury

1974 ◽  
Vol 32 (02/03) ◽  
pp. 704-713 ◽  
Author(s):  
F. N McKenzie ◽  
K.-E Arfors ◽  
N. A Matheson
Keyword(s):  
Inhibitory Effect ◽  
Microvascular Blood Flow ◽  
Platelet Response ◽  
High Concentration ◽  
Platelet Activity ◽  
Microvascular Injury ◽  
Arterial Blood ◽  
Proximal Site ◽  
Adenosine Phosphates

SummaryA study has been made of the biochemical factors underlying the platelet response to laser-induced microvascular injury. A platelet aggregating substance is produced at sites of laser-induced injury which markedly stimulates platelet activity at a site of injury inflicted a short distance downstream. Distal sites of injury are not similarly influenced if the distance between the injuries is increased or if the proximal site no longer shows platelet-stimulating activity. The stimulating effect of an adjacent proximal injury on platelet activity at a distal site is inhibited by local intra-arterial infusion of adenosine. Measurements of arterial blood pressure and microvascular blood flow velocity during adenosine infusion showed that its inhibitory effect on platelet activity is largely independent of its vasodilator properties. The effect of infusion of different adenosine phosphates (AMP, ADP, ATP) was also studied. Very small amounts of ADP markedly stimulated platelet activity and the emboli formed were similar to those normally produced at sites of laser injury. At high concentration AMP inhibited while ATP stimulated platelet activity in vivo. The results emphasise the fundamental role of ADP as a mediator of the platelet response at sites of laser- induced microvascular injury.

Functional Involvement of Thrombospondin in Platelet Aggregation Induced by Low Versus High Concentrations of Thrombin

1986 ◽  
Vol 55 (01) ◽  
pp. 136-142 ◽  
Author(s):  
K J Kao ◽  
David M Shaut ◽  
Paul A Klein
Keyword(s):  
Platelet Aggregation ◽  
Binding Sites ◽  
Inhibitory Effect ◽  
Activated Platelets ◽  
Low Concentrations ◽  
Platelet Binding ◽  
Functional Involvement ◽  
Thrombin Activation ◽  
Platelet Aggregates ◽  
High Concentrations

SummaryThrombospondin (TSP) is a major platelet secretory glycoprotein. Earlier studies of various investigators demonstrated that TSP is the endogenous platelet lectin and is responsible for the hemagglutinating activity expressed on formaldehyde-fixed thrombin-treated platelets. The direct effect of highly purified TSP on thrombin-induced platelet aggregation was studied. It was observed that aggregation of gel-filtered platelets induced by low concentrations of thrombin (≤0.05 U/ml) was progressively inhibited by increasing concentrations of exogenous TSP (≥60 μg/ml). However, inhibition of platelet aggregation by TSP was not observed when higher than 0.1 U/ml thrombin was used to activate platelets. To exclude the possibility that TSP inhibits platelet aggregation by affecting thrombin activation of platelets, three different approaches were utilized. First, by using a chromogenic substrate assay it was shown that TSP does not inhibit the proteolytic activity of thrombin. Second, thromboxane B2 synthesis by thrombin-stimulated platelets was not affected by exogenous TSP. Finally, electron microscopy of thrombin-induced platelet aggregates showed that platelets were activated by thrombin regardless of the presence or absence of exogenous TSP. The results indicate that high concentrations of exogenous TSP (≥60 μg/ml) directly interfere with interplatelet recognition among thrombin-activated platelets. This inhibitory effect of TSP can be neutralized by anti-TSP Fab. In addition, anti-TSP Fab directly inhibits platelet aggregation induced by a low (0.02 U/ml) but not by a high (0.1 U/ml) concentration of thrombin. In conclusion, our findings demonstrate that TSP is functionally important for platelet aggregation induced by low (≤0.05 U/ml) but not high (≥0.1 U/ml) concentrations of thrombin. High concentrations of exogenous TSP may univalently saturate all its platelet binding sites consequently interfering with TSP-crosslinking of thrombin-activated platelets.

scholarly journals Inhibitory Effects of Secondary Metabolites from the Lichen Stereocaulon evolutum on Protein Tyrosine Phosphatase 1B

Planta Medica ◽  
2021 ◽  
Author(s):  
Birgit Waltenberger ◽  
Françoise Lohézic-Le Dévéhat ◽  
Thi Huyen Vu ◽  
Olivier Delalande ◽  
Claudia Lalli ◽  
...  
Keyword(s):  
Protein Tyrosine Phosphatase ◽  
Inhibitory Activity ◽  
Tyrosine Phosphatase ◽  
Inhibitory Effect ◽  
Positive Control ◽  
Protein Tyrosine Phosphatase 1B ◽  
Protein Tyrosine ◽  
Ic50 Values ◽  
A Cell

AbstractProtein tyrosine phosphatase 1B plays a significant role in type 2 diabetes mellitus and other diseases and is therefore considered a new drug target. Within this study, an acetone extract from the lichen Stereocaulon evolutum was identified to possess strong protein tyrosine phosphatase 1B inhibition in a cell-free assay (IC50 of 11.8 µg/mL). Fractionation of this bioactive extract led to the isolation of seven known molecules belonging to the depsidones and the related diphenylethers and one new natural product, i.e., 3-butyl-3,7-dihydroxy-5-methoxy-1(3H)-isobenzofurane. The isolated compounds were evaluated for their inhibition of protein tyrosine phosphatase 1B. Two depsidones, lobaric acid and norlobaric acid, and the diphenylether anhydrosakisacaulon A potently inhibited protein tyrosine phosphatase 1B with IC50 values of 12.9, 15.1, and 16.1 µM, respectively, which is in the range of the protein tyrosine phosphatase 1B inhibitory activity of the positive control ursolic acid (IC50 of 14.4 µM). Molecular simulations performed on the eight compounds showed that i) a contact between the molecule and the four main regions of the protein is required for inhibitory activity, ii) the relative rigidity of the depsidones lobaric acid and norlobaric acid and the reactivity related to hydrogen bond donors or acceptors, which interact with protein tyrosine phosphatase 1B key amino acids, are involved in the bioactivity on protein tyrosine phosphatase 1B, iii) the cycle opening observed for diphenylethers decreased the inhibition, except for anhydrosakisacaulon A where its double bond on C-8 offsets this loss of activity, iv) the function present at C-8 is a determinant for the inhibitory effect on protein tyrosine phosphatase 1B, and v) the more hydrogen bonds with Arg221 there are, the more anchorage is favored.

Central indomethacin enhances volume-dependent vasopressin release

1984 ◽  
Vol 247 (6) ◽  
pp. R1017-R1021
Author(s):  
D. P. Brooks ◽  
L. Share ◽  
J. T. Crofton ◽  
A. Nasjletti
Keyword(s):  
Blood Pressure ◽  
Prostaglandin E2 ◽  
Mean Arterial Blood Pressure ◽  
Inhibitory Effect ◽  
Volume Depletion ◽  
Vasopressin Release ◽  
Arterial Blood ◽  
Ventriculocisternal Perfusion ◽  
Severe Hemorrhage ◽  
Vasopressin Secretion

The effect of centrally administered indomethacin on hemorrhage-induced vasopressin release was studied in the morphine-sedated, urethan/chloralose-anesthetized dog. Ventriculocisternal perfusion of indomethacin 1) significantly reduced the amount of prostaglandin E2 in the effluent from the cisterna magna, 2) significantly enhanced the vasopressin response to volume depletion, and led to a greater fall in mean arterial blood pressure during severe hemorrhage. The results suggest that central prostaglandins may have an inhibitory effect on vasopressin secretion during volume depletion.

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