BLOOD PLASMA PROTEIN REGENERATION AS INFLUENCED BY INFECTION,DIGESTIVE DISTURBANCES,THYROID, AND FOOD PROTEINS : A DEFICIENCY STATE RELATED TO PROTEIN DEPLETION

When blood plasma proteins are depleted by bleeding, with return of washed red cells (plasmapheresis), it is possible to bring dogs to a steady state of low plasma protein in the circulation and a uniform plasma protein production on a basal diet. Such dogs become test subjects by which the effect of various factors on plasma protein regeneration can be measured. Dogs previously the subjects of plasmapheresis, during long rest periods appear to increase their stores of plasma protein building materials and their blood plasma protein concentrations above former normal levels. A sterile abscess (turpentine) induces a marked reduction in plasma protein regeneration in these test dogs consuming an ample basal diet. The sharp reduction during the initial 24 hours may in part reflect an extravasation of plasma protein into the injured tissue but there also appears to develop a true disturbance of the mechanism which produces plasma proteins. Digestive disturbances interfere seriously with plasma protein production. Whereas large quantities of live yeast upset digestion and form no plasma protein, autoclaved yeast is well utilized, having a potency ratio of 4.4. Amino acids have been tested inadequately. A mixture of cystine, glutamic acid, and glycine does seem to have a definite effect upon protein metabolism and plasma protein production. Iron, under the conditions of these experiments, does not influence the output of plasma proteins. Liver extract (parenteral) is also inert. The proteins of red blood cells when added to the diet are poorly utilized for plasma protein formation and show a potency ratio of only 10.1. Kidney protein added to the kidney basal diet shows a potency ratio of about 5 as compared with 4.6 for that basal diet. A digest of beef stomach and rice polishings shows a potency ratio of about 7.9. Dried powdered serum shows a potency ratio of 3.5, which is much less than fresh serum (2.6). Powdered thyroid fed in doses sufficient to accelerate body metabolism shows no distinct effect upon plasma protein production not attributable to the protein in the thyroid powder itself. Long periods (25 to 30 weeks) of plasma depletion and basal diet intake remove much protein from body fluids and tissues. Associated with this protein depletion the dog loses its appetite and may vomit some food. There is loss of hair, a tendency to skin ulceration, and a distinct lowering of resistance to infection. The plasma protein output may fall to fasting levels in spite of food intake sufficient to maintain weight. We believe this condition to be a deficiency state related to severe depletion of the essential protein matrix of the body cells.     

AMINO ACID MIXTURES EFFECTIVE PARENTERALLY FOR LONG CONTINUED PLASMA PROTEIN PRODUCTION. CASEIN DIGESTS COMPARED

When blood plasma proteins are depleted by bleeding with return of red cells suspended in saline (plasmapheresis) it is possible to bring dogs to a steady state of hypoproteinemia and a constant level of plasma protein production if the diet nitrogen intake is controlled and limited. Such dogs are outwardly normal but have a lowered resistance to infection and to certain intoxications. The ten growth essential amino acids of Rose plus glycine will maintain nitrogen balance and produce as much new plasma protein as will good diet proteins. This good utilization is demonstrated over periods of several months when the amino acids are given either orally or parenterally. There is no evidence of toxicity in general nor to unnatural forms of these synthetic amino acids in particular. Given parenterally appropriate mixtures of these amino acids are well tolerated even upon rapid injection. The minimal daily requirements for a 10 kilo dog may be given intravenously in 10 minutes without reaction. Subcutaneously a 10 per cent solution may be given rapidly without reaction. Among various mixtures tested Vt approximates a minimum for a 10 kilo dog. It contains in grams (dl-threonine 0.7, dl-valine 1.5, l-(-) leucine 1.5, dl-isoleucine 1.4, dl-lysine hydrochloride 1.5, l(-) tryptophane 0.4, dl-phenylalanine 1.0, dl-methionine 0.6, l(+)-histidine hydrochloride 0.5, l(+)-arginine hydrochloride 0.5, and glycine 1.0. The presence of glycine improves tolerance to rapid intravenous injection, but excess glycine does not improve utilization of the mixture. Over a long period this mixture appears suboptimal in quantity. Doubled it is more than ample. Of two casein digests tested the one prepared by enzymatic hydrolysis provided good nitrogen retention and fairly good plasma protein production but was much less tolerable upon intravenous injection than certain mixtures of pure amino acids. The other one prepared by acid hydrolysis and tryptophane fortification afforded bare nitrogen equilibrium and produced virtually no plasma protein. Skin lesions observed after 10 to 20 weeks of synthetic diet probably reflect a deficiency of some member or members of the vitamin B₂ group. A persistent slight weight loss in the face of a strongly positive nitrogen balance may accompany this deficiency.     

TEN AMINO ACIDS ESSENTIAL FOR PLASMA PROTEIN PRODUCTION EFFECTIVE ORALLY OR INTRAVENOUSLY

When blood plasma proteins are depleted by bleeding with return of the washed red cells (plasmapheresis) it is possible to bring dogs to a steady state of hypoproteinemia and a constant level of plasma protein production if the diet protein intake is controlled and limited. Such dogs are outwardly normal but have a lowered resistance to infection and to certain intoxications. When the protein intake of such dogs is completely replaced by the growth mixture (Rose) of crystalline amino acids, plasma protein production is excellent, weight and nitrogen balance are maintained. This growth mixture consists of ten amino acids, threonine, valine, leucine, isoleucine, tryptophane, lysine, phenylalanine, methionine, histidine, arginine, and is as effective as most diet proteins in plasma protein production. The above amino acid mixture in aqueous solution may be given by vein with equally good plasma protein production and no apparent clinical disturbance even when given rapidly. Cystine may replace methionine in the above mixture with equally good plasma protein production for 7 to 10 days but at the expense of the body tissues, that is, with weight loss and a negative nitrogen balance. The addition of cystine to the protein-free, otherwise adequate diet may result in the production of considerable new plasma protein during a period as long as 1 week (cystine effect). This reaction may depend upon the amino acid constitution of the preceding diet protein in that it occurred following a liver feeding but did not occur after pancreas feeding. Arginine is required in the diet of the protein depleted dog for fabrication of plasma protein. It is apparently not needed for nitrogen balance for as long as 1 or 2 weeks. The omission of either threonine or valine from the growth mixture is quickly followed by a sharp decline in plasma protein formation and by a negative nitrogen balance. When histidine, arginine, and most of the lysine are omitted from the growth mixture, nitrogen balance and weight may be maintained for as long as 1 week but plasma protein production falls off markedly. The findings indicate that the growth mixture of amino acids should be a valuable addition to transfusion and infusion therapy in disease states associated with deficient nitrogen intake or tissue injury and accelerated nitrogen loss, including shock, burns, and major operative procedures.     

Pilot Study to Quantify Palladium Impurities in Lead-like Compounds Following Commonly Used Purification Techniques

Palladium-catalyzed reactions are among the most commonly used procedures in organic synthesis. The products have a range of uses, including as intermediates in total synthesis and as screening compounds for drug discovery or agrochemical projects. Despite the known and potentially deleterious effects of low-level metal impurities in biological assays, the quantification of metal remaining in reaction products to verify the effective removal of the transition element is rarely reported. Using palladium as an exemplar, we describe a pilot study that for the first time quantifies residual metal levels in reaction products following increasingly rigorous purification protocols. Our results demonstrate that significant levels of residual palladium can remain in isolated reaction products following chromatographic purification, and only by using a subsequent metal scavenging step are they reliably reduced to a low level. Finally, we provide a set of simple guidelines that should minimize the potential for issues associated with residual palladium in reaction products.