Changes In Albumin Concentration Research Articles

Acute suppression of albumin synthesis in systemic inflammatory disease: an individually graded response of rat hepatocytes.

The effects of an inflammatory insult on albumin of the rat liver were investigated at the cellular level and were correlated with serum albumin concentration. After SC injection of turpentine, the livers were perfused and fixed in vivo; serial liver sections were stained using a streptavidin-ABC-immunoperoxidase technique with an antibody to rat albumin. Albumin and total protein were measured at intervals after turpentine injection in whole livers and in serum. Fibrinogen was determined in plasma only. Twenty-four hours after turpentine injection serum albumin had dropped by 25% and was at 50% of its initial value at Day 3. Serum fibrinogen increased 2.4-fold within 24 hr and decreased thereafter. Liver homogenates showed no significant changes in albumin concentration. Immunohistochemically, all hepatocytes stained positive for albumin in normal animals. During inflammation, the immunostainable albumin content vanished entirely in a majority of all hepatocytes while remaining unchanged in other cells, thus producing a strikingly patchy staining pattern. No signs of resumption of albumin accumulation in depleted hepatocytes were seen after 8 days, despite a clear trend towards normalization of serum albumin concentration. These results suggest that individual hepatocytes differ widely in their response to agents that suppress albumin synthesis in an acute-phase reaction.

Coronary resistance increase by nondefatted albumin in saline-perfused rabbit hearts

In isolated hearts perfused with salt solutions, albumin is often added in low concentrations for preservation of endothelial function. Albumin in low concentrations is also sometimes used as an intravascular indicator in such preparations. We perfused isolated rabbit hearts according to Langendorff with a constant flow of Tyrode solution. Despite maximal vasodilation with 10 microM adenosine, coronary vascular resistance increased by 14% after 0.3 g/100 ml nondefatted bovine serum albumin (Sigma A-9647) was added to the perfusate compared with the control resistance with no albumin present. The 50% response time for the vasoconstrictive response to the step change in albumin concentration was 20 +/- 13 s (mean +/- SD). When 0.3 g/100 ml of defatted albumin (Sigma A-6003) was added, the resistance increase was only 1.4% and is explained by increased viscosity. Vasoconstrictive effects of certain nondefatted albumin preparations must be taken into account by investigators who perfuse organs with albumin-containing solutions.

Assessment of AlbuSure and its usefulness in identifying IDDM subjects at increased risk for developing clinical diabetic nephropathy.

This study, which included 154 participants in a 10-yr follow-up study of diabetes complications, was conducted to evaluate AlbuSure (a qualitative test designed to detect urinary albumin concentrations greater than 0.03 g/L) for its ability to discriminate between albumin concentrations above and below the manufacturer's concentration threshold and to identify individuals at increased risk for developing diabetic nephropathy (i.e., those with albumin excretion rate [AER] greater than 0.0288 g/24 h). The reproducibility of AlbuSure results was also evaluated. The results of these evaluations were examined by three different types of urine collections (24 h, overnight, and timed postclinic) and overall. AlbuSure's validity was examined by comparing its results to immunonephelometrically measured concentrations and AER. When compared to albumin concentration, AlbuSure had an overall sensitivity of 81.8%, specificity of 94.8%, and positive predictive value of 90.6%. AlbuSure's sensitivity was lower (71.4%) when compared with AER; however, this was higher than the sensitivity achieved by dipsticks against AER (50.7%). On testing urine samples stored for 3 days at 4 degrees C, AlbuSure results were 100% reproducible after 1 day and had an overall reproducibility of 92% after 3 days. When urine was retested after 3 and 15 mo of storage at -70 degrees C, AlbuSure was greater than or equal to 90% reproducible, with some of the differing results attributable to corresponding changes in albumin concentration. The overnight sample appeared to be the sample of choice for testing with AlbuSure in that it showed excellent reproducibility and the highest sensitivity (compared to both albumin concentration and AER).

The ex vivo plasma protein binding of theophylline in renal disease.

The plasma protein binding of theophylline was measured in 21 patients with renal disease and 21 healthy age and sex matched controls. The percentage of theophylline unbound to plasma was greater in patients with nephrotic syndrome and in chronic renal failure than in controls. In nephrotic syndrome the impairment of drug binding mirrored the marked degree of hypoalbuminaemia seen in this condition but in chronic renal failure the impairment of protein binding was greater than would be expected from the plasma albumin concentration changes. The percentage of theophylline free in plasma in renal disease may be increased (by as much as 50%). Such changes should be taken into account in interpreting the relationship between total plasma theophylline concentration and drug effect in renal disease.

Effects of human serum albumin concentration on binding of [3H]amphetamine, [3H]atropine, [3H]epinephrine, and [14C]histamine

The binding of [3H]amphetamine, [3H]atropine, [3H]epinephrine, and [14C]histamine to human serum albumin was examined with a constant ligand concentration and varying albumin concentrations. Two concentrations of each ligand were studied. Scatchard plots of the binding data were linear and had positive slopes; the slopes were greater at the higher ligand concentration. The lowest point was for the highest albumin level and increased in sequence to the lowest albumin concentration. The β (fraction bound) value increased with an increasing amount of albumin in the system. The change in β per change in albumin concentration [d(β)/d(albumin)] when plotted against albumin concentration yielded curves with negative slopes; the slope was greatest at the lower albumin levels and was much less at the higher albumin levels (equivalent to those encountered in human blood). In agreement with literature data for other systems, the nK value (number of binding sites times the association constant) decreased with increasing albumin concentration. In previous studies of the same ligands and protein, when the albumin concentration was kept constant and the ligand concentration was varied, the Scatchard plots had positive slopes. Positive slopes also were found in this study with constant ligand concentrations and varying albumin levels. These results suggest cooperativity in the binding of these ligands to human serum albumin.

Changes in expression of albumin and alpha-fetoprotein genes during rat liver development and neoplasia.

Albumin mRNA was isolated and purified from rat liver polysomes by a combination of immunoprecipitation of specific polysomes, poly(U)-Sepharose 4B chromatography, and fractionation of the resulting poly(A)-containing RNA on a sucrose gradient. alpha-Fetoprotein (AFP) mRNA was isolated from Morris hepatoma 7777 by a similar procedure. The purity of the mRNA preparations was determined by analytical gel electrophoresis under denaturing conditions, analysis of sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the polypeptides synthesized in a wheat germ cell-free system, and the kinetics of hybridization to cDNA transcribed from albumin mRNA and AFP mRNA. The albumin mRNA possessed a chain length of approximately 2265 nucleotides and the AFP mRNA possesed a length of approximately 2235 nucleotides when examined under stringent denaturing conditions on agarose gels containing 10 mM methylmercury hydroxide. Analysis of poly(A) content by a hybridization assay with [3H]poly(U) revealed the presence in albumin mRNA of a poly(A) region containing approximately 100 adenosine residues. The AFP mRNA preparation was found to contain an average poly(A) tract of approximately 190 bases. Thus, albumin mRNA appears to contain approximately 330 untranslated nucleotides, and AFP mRNA appears to contain a similar number (approximately 285) of noncoding, nonpoly(A) bases. The purified albumin and AFP mRNA's were used as templates for synthesis of full-length cDNA hybridization probes. Both of the probes selectively hybridized to their templates with kinetics expected for single RNA species the sizes of albumin and AFP mRNA. ROt analysis was used to quantitate albumin and AFP mRNA sequences during normal liver postnatal development and liver oncogenesis. The number of polysomal AFP mRNA molecules per liver was found to drastically decrease during the first weeks of postnatal life, concomitant with a decline in the AFP synthetic capacity of the livers and in the serum concentrations of AFP. During this period, the concentration of albumin mRNA molecules per cell in the liver remained at high, approximately constant levels. In Morris hepatoma 7777, the concentration of AFP-specifying sequences was at least 10(3)-fold higher than that found in normal adult liver, whereas the content of albumin nRNA was four- to five-fold lower. These changes in concentration of albumin and AFP mRNA sequences closely correlated with a parallel variation in the specific protein synthetic capacity of the tissues.

A quantitative radioautographic comparison of albumin concentration in different sized lymph vessels in normal mouse lungs

We have by the use of quantitative radioautography, compared the concentration of albumin in lymph in small and large lung lymph vessels in the mouse. We injected 125I-albumin intravenously. Four hours later, we fixed the lungs by either vascular perfusion with a fixative solution or by rapid freezing. From tissue blocks embedded in Epon, we cut 1 μm thick sections, which we covered with nuclear emulsion. We counted the radioautographic grains overlying the different lymph vessels, measured the area and diameter of these vessels, and calculated the number of grains per unit area of lymph vessel lumen. In the rapidly frozen lungs, we found that there was no difference in grain density between the differently sized lymph vessels. In two out of five perfusion fixed lungs, we found a tendency toward decrease in grain density with increasing lymph vessel diameter. We are inclined to believe that this latter observation is a result of the fixation method used. Our conclusion is, this study gives evidence that in the normal lung there is no change in albumin concentration as the lymph flows along the lymph vessels.

In vivo labeling of cytoplasmic RNA in neurons of the immature brain cortex

only the total and the nuclear RNAs were analyzed. The present report describes a procedure for the isolation of the neuronal cytoplasmic RNA and its application to the measurement of the approximate maturation time of its ribosomal RNA component in 8- and 20-day-old cerebral cortex perikarya. While this work was in progress a report describing the labeling pattern of neuronal and glial cytoplasmic RNA isolated from the whole brain of adult rats has appeared ~. Neuronal perikarya were isolated as described previously, except for the following modification: the solution employed for tissue suspension contained 7.5 ~ polyvinylpyrrolidone (w/v), 10 mM CaC12 and 4 ~ (w/v) instead of the 1 ~ bovine serum albumin previously used 1°. With this change in albumin concentration the suspension solution becomes isotonic. The yield and preservation of the perikaryal fraction and its purity were described 9,1°. In each experiment 10 rats were injected intrathecally with 10/~Ci of [5-aH]uridine (Amersham/Searle, 20 Ci/mmole). The neuronal perikarya were suspended in 3 ml of a solution consisting of 0.2 M sucrose- 0.06 M NaCI0.1 M Tris-HC1 buffer, pH 7.6, and the suspension was homogenized by means of 3 strokes in a glass-teflon loose-fitting homogenizer. The homogenate was centrifuged at 2,000 × g for 10 min and the supernatant was aspirated and stored in ice. This procedure was repeated and the supernatant pool was brought up to 0.25 ~ Macaloid (American Tansul Co., Houston, Texas), 0.01 M EDTA and 50/~g/ml of polyvinyl

Does haemoconcentration account for the changes in serum enzyme activities following haemodialysis?

We have estimated serum lactate dehydrogenase and isoenzymes, alkaline phosphatase, aspartate aminotransferase, amylase, creatine kinase, urea, creatinine and albumin on 29 patients with end-stage renal failure, before and after regular maintenance haemodialysis. All enzymes except serum aspartate aminotransferase, creatine kinase and LDH 1 were significantly increased (0.01 > P > 0.001 or P < 0.001) following dialysis. Because of the significant changes in serum albumin ( P < 0.001) following dialysis, correction was made to all post-dialysis enzyme activities for the degree of haemoconcentration. When corrected no changes occurred in any of these enzyme activities following haemodialysis. We have also confirmed that in vitro dialysis of a predialysis serum does not alter the LDH isoenzyme activities, when corrections are made for changes in albumin concentration.