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C Zukoski

Publications and source records attributed to C Zukoski.

9 recordsLinked to original sources
PubMed1999

Effect of glycerol on the interactions and solubility of bovine pancreatic trypsin inhibitor.

The effects of additives used to stabilize protein structure during crystallization on protein solution phase behavior are poorly understood. Here we investigate the effect of glycerol and ionic strength on the solubility and strength of interactions of the bovine pancreatic trypsin inhibitor. These two variables are found to have opposite effects on the intermolecular forces; attractions increase with [NaCl], whereas repulsions increase with glycerol concentration. These changes are mirrored in bovine pancreatic trypsin inhibitor solubility where the typical salting out behavior for NaCl is observed with higher solubility found in buffers containing glycerol. The increased repulsions induced by glycerol can be explained by a number of possible mechanisms, all of which require small changes in the protein or the solvent in its immediate vicinity. Bovine pancreatic trypsin inhibitor follows the same general phase behavior as other globular macromolecules where a robust correlation between protein solution second virial coefficient and solubility has been developed. This study extends previous reports of this correlation to solution conditions involving nonelectrolyte additives.

Animals↗
PubMed1993

Association of cyclosporin A with acquired cystic kidney disease of the native kidneys in renal transplant recipients.

Acquired cystic kidney disease (ACKD) is a common complication in patients treated with long-term dialysis. Previous studies performed prior to the cyclosporin A (CsA) era indicate that successful renal transplantation causes regression of ACKD. Little has been published, however, on the occurrence of ACKD in CsA-treated transplant recipients. We conducted a prospective sonographic study in 33 renal transplant recipients and 32 dialysis patients to evaluate the effect of CsA on ACKD in transplant recipients. Transplant recipients had a lower prevalence (39% vs. 56% in dialysis patients) and severity (smaller kidneys and lower cyst grades) of ACKD when compared with dialysis patients. Renal cell carcinoma was found in two dialysis patients. Using multiple regression analysis, we found that the use of CsA was significantly correlated with the presence of ACKD in transplant recipients (57% in CsA-treated vs. 8% in non-CsA-treated patients). We conclude that renal transplantation reduces the prevalence and severity of ACKD in the native kidneys; however, among transplant patients, CsA administration is associated with a greater prevalence of ACKD.

Adult↗
PubMed1977

The effect of jejunoileal bypass on the pharmacokinetics of digoxin in man.

Seven subjects who underwent jejunoileal bypass surgery for massive obesity participated in a study to examine the relative bioavailability of digoxin before and one to two months after surgery. They were given a loading dose of 1 mg digoxin in divided oral doses followed by oral maintenance doses of 0.5 mg daily. There were no significant differences in the area under the serum concentration time curve, steady state serum levels or 24 hour steady state excretion of digoxin before and after surgery. We conclude that the bioavailability of digoxin from the Lanoxin tablets employed is not impaired in these patients, although urinary d-xylose and 24 hour fecal fat excretion indicated moderate to severe malabsorption after surgery.

Digoxin↗
PubMed1977

Inhibition of some functions of polymorphonuclear leukocytes by in vitro zinc.

In granulocytes isolated by dextran sedimentation from dog blood, the O2 consumption, phagocytosis of yeast particles, and E. coli killing were tested in Tris-guffered saline medium with additions of Zn++, Mg++, and other divalent cations and in the presence or absence of plasma. Zn++ inhibited all three cell functions in a concentration-related manner only in the presence of 1.2 mM Mg++. Without Mg++ in the medium the lower concentrations of Zn++ (17 to 67 muM) were stimulatory; 83 muM Zn++ concentration was inhibitory. A close association was found between the inhibitory effect of Zn++ and the actual content of zinc in the cell: (1) the uptake of zinc from the medium was minimal during the first minute, where no Zn++ effect on cell functions was manifest, (2) when zinc-loaded cells with inhibited activity were washed and reincubated for at least 15 minutes in zinc-free medium, almost 95 per cent of the zinc was washed out and cell activity was normalized. This indicated reversibility of the zinc effect, (3) in the presence of increasing concentrations of autologous plasma in the medium, the effect of zinc was proportionally less pronounced and at the same time uptake of zinc by cells was decreased. Of the six divalent cations studied at 50 muM concentration and in the presence of Mg++, only Zn++ was inhibitory, Se and Co were inactive, and Mn and Cu stimulated O2 consumption of latex-activated granulocytes. We conclude that zinc ions, in the presence of Mg++ in the medium, inhibit various functions of dog peripheral granulocytes and this effect is closely associated with zinc uptake by the cells. The effect is reversible and specific for this metal.

Animals↗