Ambivalent effect of protein binding on computed distributions of metal ions complexed by ligands in blood plasma

Summary Although the absolute concentrations of metal complexes in blood plasma are controlled by protein binding, the percentage distribution of transition metal ions amongst low molecular weight ligands is not. Thus, computer simulations which omit protein equilibria can nevertheless afford reliable information about such metals in the biofluid.Acknowledgments. One of us (P. M. M.) thanks the University of Cape Town and the C. S. I. R. for financial assistance. Computations were performed on both of the University of Cape Town's UNIVAC 1106 system and the St. Andrews University's IBM 360/44. Address ofP. W. Linder: University of Cape Town, Rondebosch, Cape (South Africa).     

Down's syndrome: changes in protein fractions of blood plasma

Summary A statistically significant decrease of prealbumin and statistically significant increases of alpha₂-macroglobulin and IgA were found in blood plasma of patients with Down's syndrome using quantitative crossed immunoelectrophoresis.We are indebted to Prof. T.C. Bøg-Hansen, University of Copenhagen, for the helpful discussion of our results.     

The effect of ACTH on cholinesterase activity in plasma,whole blood,and blood cells of rats

Résumé On a déterminé chez des rats l'activité cholinestérasique dans le plasma, sang total et cellules sanguines avant et après l'administration d'ACTH. On a constaté une augmentation hautement significative:P: 0,001 après l'administration de cette hormone.     

Shape change of blood platelets induced by myelin basic protein.

Myelin basic protein (MBP) isolated from bovine spinal cord caused a marked shape change reaction of human blood platelets which was not accompanied by the release reaction and not inhibited by methysergide and spiroperidol. Only those basic proteins, including MBP, which had previously shown to exert neuronal depolarisation also induced the shape change reactions. Therefore, these findings may extend the use of platelets as neuronal models.     

The effect of skim milk on plasma cholesterol in rats.

From the 15th day of birth, newborn rats were offered rat chow mixed with water or skim milk. The former also received tap water, the latter skim milk. In the latter group, plasma cholesterol was lowered in 43- and 64-day-old males and in 64-day-old females.     

Specific binding of 3H-progesterone to a plasma protein in the guinea pig fetus]

The presence of a protein that binds specifically and with high affinity to progesterone is found in the plasma of fetal guinea Pig. Progesterone and 5 alpha-dihydroxyprogesterone strongly compete for the 3H-progesterone-protein complex. 5 beta-dihydroxy progesterone, 20 beta-dihydroxyprogesterone, testosterone and synthetic progestagen, R-5020 (17,21-dimethyl-19-norpregna-4, 9-diene-3,20 dione), also compete but less intensely. 17-hydroxyprogesterone, aldosterone, cortisol, oestradiol and oestrone have no effect. The 3H-progesterone-protein, complex has an affinity of Kd = 8.8 +/- 3.5 x 10(-10) M and in sucrose density gradient the sedimentation coefficient is 4.6 S.     

Effects of X-irradiation on ribonucleases in blood plasma

Zusammenfassung Unter Bestrahlung wurde die RNAse-Aktivität im Blut untersucht. Es zeigte sich, dass Bestrahlung des Kopfes allein zu einer starken Erhöhung der alkalischen RNAse im Serum führt.     

The effect of shock on blood oxidation-reduction potential.

Oxidation-reduction (redox) potential measurements were made in the blood of rabbits subjected to hemorrhagic shock followed by treatment with a mild oxidizing agent (albumin). Control redox potential reading corrected for pH was -8.8 +/- 1.3 millivolts (mV) in arterial blood (A) and -18.0 +/- 2.0 mV in venous blood (V). This A-V difference indicated that hydrogen equivalents coming from muscle and other tissues were partially consumed in the lungs. A 20-mV drop on the V and a 13 mV on the A side was seen after shock. This did not fully return to control 2 h after return of the shed blood. Infusion of 2 g of albumin/kg/h raised the V redox potential to control, but it returned to untreated levels when the albumin was discontinued. The reductive load imposed on the animal by shock appeared to be large and not readily reversed by reperfusion or by the quantity of albumin given. Thus, it may be concluded that cellular respiration had not been adequately restored. This reductive load may impede recovery by suppression of cellular respiration and other cell and organ functions.     

The effect of sulfhydryl reagents on cation binding by membrane fragments

Zusammenfassung Nachweis an Lebermikrosomen der Ratte, dass Sulfhydryl Reagenzienp-Chloromercuribenzoat (pCMB) undp-Chloromercuribenzol Sulfonat (pCMBS) die Bindung von Magnesium und Calcium ungefähr um 20% vermindern.

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I wish to thank Dr.George L. Ellman for several of the sulfhydryl reagents and for discussions relating to the present study. I also wish to thank Mr.Thian Vui Mark Lee for his capable assistance during the course of this investigation.     

Effects of blood sampling, anesthesia and surgery on plasma vasopressin concentration in rats.

The influence of blood sampling, anesthesia and surgery on plasma vasopressin concentration was assessed in rats. Mean plasma concentration in conscious, chronically catheterized rats was 1.4 +/- 0.1 pg/ml (n = 6). This value remained constant over repeated plasma samplings in the same animals. On the other hand, decapitation increased the plasma vasopressin concentration to 6.0 +/- 2.4 (in pg/ml) (n = 6), inactin anesthesia to 2.9 +/- 0.6 (n = 6), anesthesia and femoral cannulation to 13.3 +/- 5.8 (n = 6) and surgery for renal micropuncture to 81.3 +/- 35.0 (n = 6). It is concluded that the level of circulating plasma vasopressin is highly dependent on the sampling technique and is closely related to the extent of surgery.     

Demonstration of a specific androgen binding protein (ABP) in the seminal plasma of the ram]

A specific androgen binding protein has been demonstrated in the seminal plasma of adult Ram. This protein binds especially to 5 alpha-DHT and testosterone and much lower to oestradiol-17 beta. Its characteristics such as Ka (in order 10(9) M(-1) at 4 degrees C), relative mobility (Rf) and its specificity are similar to those of the androgen binding protein (ABP) of the Rete Testis Fluid and the epididymal plasma of the Ram. It is probable that this protein secreted from the testis, crosses the epididymis before being secreted in the seminal plasma at the moment of the ejaculation.     

Inhibitory effect of beta-ecdysone on protein synthesis by blowfly fat body in vitro

Synthesis of blow fly calliphorin and other blood proteins by larval fat body in organ culture is inhibited by beta-ecdysone. The findings suggest a novel function for the hormone.     

Specific metal binding sites on calcified concretions in epithelial cells of the clam kidney

Summary Calcified granules (concretions) in the kidneys of bivalve molluscs are able to absorb metals from solution and this ability is the result of the existence of saturable, medium affinity metal binding sites on the concretions. In addition different metals may compete for the same sites so that some metals will be accumulated preferentially over others.