Albumin adsorption onto surfaces of urine collection and analysis containers.

BACKGROUND: Adsorption of albumin onto urine collection and analysis containers may cause falsely low concentrations. METHODS: We added (125)I-labeled human serum albumin to urine and to phosphate buffered solutions, incubated them with 22 plastic container materials and measured adsorption by liquid scintillation counting. RESULTS: Adsorption of urine albumin (UA) at 5-6 mg/l was <0.9%; and at 90 mg/l was <0.4%. Adsorption was generally less at pH8 than pH5 but only 3 cases had p<0.05. Adsorption from 11 unaltered urine samples with albumin 5-333 mg/l was <0.8%. Albumin adsorption for the material with greatest binding was extrapolated to the surface areas of 100 ml and 2l collection containers, and to instrument sample cups and showed <1% change in concentration at 5 mg/l and <0.5% change at 20 mg/l or higher concentrations. Adsorption of albumin from phosphate buffered solutions (2-28%) was larger than that from urine. CONCLUSIONS: Albumin adsorption differed among urine samples and plastic materials, but the total influence of adsorption was <1% for all materials and urine samples tested. Adsorption of albumin from phosphate buffered solutions was larger than that from urine and could be a limitation for preparations used as calibrators.

Absorçäo de líquido de irrigaçäo na ressecçäo transuretral da próstata em cäes / Irrigating fluid absorption during transurethral resection of the prostate in dogs

Trinta e dois cäes submetidos a entubaçäo do ducto torácico e cateterismo bilateral dos ureteres, foram divididos em 3 grupos: A- 4 cäes inoculados com RISA 131 I ou EDTA 51 Cr por via intravenosa ou peri-prostática; B- controle de 8 cäes submetidos a irrigaçäo vesical e prostática com 8 litros de glicina a 1,2 por cento contendo os marcadores radioativos; C- 8 cäes manejados como em B mas sujeitos à RTU da próstata. Os cäes foram acompanhados por 5 horas. A absorçäo de líquido de irrigaçäo foi calculada pelos métodos volumétrico e radioisotópico. Em 5 horas, 97 por cento da RISA 131 I inoculada via intravenosa permanecia neste espaço enquanto apenas 4,6 por cento da injetada no espaço peri-prostático penetrou no compartimento vascular. Para o EDTA 51 Cr, 63,6 por cento da massa inoculada no espaço peri-prostático foi recuperada na urina após 5 horas. O método volumétrico mostrou absorçäo média de 22,7 ml no grupo B e 276 ml no C, e o radioisotópico de 6,3 ml e 165,4 ml, respectivamente. O modelo experimental tem similaridades com o ser humano

The intrarenal distribution of 125I-albumin in the Syrian hamster.

The intrarenal distribution of radioiodinated human serum albumin (125RISA) after intravenous injection was studied in Syrian hamsters by scintillation counting and frozen section autoradiography. After 15, 30 and 60 min the virtual plasma albumin space in the renal cortex of the hamster represented 6.49, 7.13, and 8.06 percent respectively of the kidney tissue volume. From the cortex to the renal papilla the albumin space increased to about 30 percent of the tissue volume. In comparison to this the albumin space in the renal cortex of the rat was about 20% and in the renal papilla about 33% (11). Frozen section autoradiography indicated that the distribution of radioalbumin in the renal cortex of the Syrian hamster is limited mainly to the kidney vessels, being especially noticeable in the glomerular capillaries. Toward the papilla increasingly greater (mainly extratubular) activity could be observed not only intravascularly but also interstitially. In the cortex of the rat kidney, on the other hand, radioactive albumin was accumulated (probably by filtration and reabsorption) predominantly in the proximal tubular epithelium. Wtithin 30 min thekidneys of the rat excreted mor than 10 times as much 125I than the hamster kidneys. These results (substantially less cortical accumulation and urinary excretion of radioalbumin in the Syrian hamster) indicate that, in contrast to the rat, obviously much less albumin is filtered (and then accumulated by proximal reabsorption) by the Syrian hamster glomeruli. This suggests that the Syrian hamster kidney is more suitable than the rat kidney for determining the interstitial, cortical, albumin space.

The effect of malnutrition on the metabolism of plasma albumin

Albumin metabolism was studied with 131 I-labled human serum albumin in malnourished infants before and after treatment. Calculation of the rate of breakdown of albumin from the slope of the decay curve of plasma radioactivity was shown to be erroneous under the conditions of these measurements. When turnover rates were calculated from the urinary excretion of 132 I, it was found that the rate of catabolism of albumin was significantly less in the malnourished state than after recovery. This may, perhaps, represent a compensatory reaction to protein depletion. It is suggested that the rapid regeneration of plasma albumin that occurs in response to treatment is produced mainly by the decreased rate of catabolism, rather than by an increased rate of albumin synthesis (AU)