Changes in activity of the renin-angiotensin system of the rat by induction of acute inflammation

Angiotensinogen is the precursor of biologically active peptide angiotensin II and its hepatic synthesis is increased by the induction of acute inflammation. Studies were carried out to know whether the rise in plasma angiotensinogen is actually involved in the activity of the renin-angiotensin system during acute inflammation. The plasma level of angiotensinogen in rats was increased to 2.5 times the normal level 16 h after the induction of acute inflammation by administration of lipopolysaccharide (LPS). The plasma renin concentration (PRC) was decreased to about 40% of the normal level concomitantly with a reduction of plasma renin activity (PRA) at 4 h after LPS administration. In contrast, 16 h after LPS injection, when plasma angiotensinogen showed a high level and PRC had recovered to the normal range, PRA was increased to 1.7 times the normal level. These results indicate that acute inflammation induced by LPS causes a biphasic change in the generation of angiotensin I, i.e., an early decrease depending upon the reduction of PRC and later increase depending upon elevation of the angiotensinogen concentration.

Free fatty acids alter calcium binding: a cause for misinterpretation of serum calcium values and hypocalcemia in critical illness

FFAs are bound with calcium on the albumin molecule. We hypothesized that changes in circulating FFA levels during critical illness altered calcium-albumin binding. We found that serum from both normal subjects and critically ill patients contained an ether-extractable factor which lowered ionized calcium concentrations and increased albumin-calcium binding. This factor was found in higher concentrations in serum from ill patients. Oleic acid and palmitic acid increased albumin-calcium binding from 2-28% in a dose-dependent manner when added in vitro to calcium-albumin solutions. Scatchard analysis demonstrated that 0.1 mM oleic acid increased the number of calcium-binding sites on the albumin molecule (from three to five sites per molecule) without altering binding affinity. A similar effect was found when we performed Scatchard analyses of ether extracts in serum from three critically ill patients (number of calcium-binding sites increased from three to six). We also found that lipid infusions (during parenteral nutrition) lowered mean serum ionized calcium values in six critically ill patients [4.6 +/- 0.2 (+/- SEM) to 4.1 +/- 0.2 mg/dL; P less than 0.05]. These data support the concept that FFAs increase calcium binding to the albumin molecule. Alterations in FFA concentrations during critical illness may contribute to the poor correlation between corrected total serum calcium and ionized calcium concentrations in critically ill patients. In addition, acute elevations in circulating FFA concentrations may contribute to hypocalcemia in patients with defects in bone calcium mobilization.

Radioimmunoassay of glandular kallikrein in human plasma after partial purification by immunoaffinity column

Glandular kallikrein in human plasma was partially purified by immunoaffinity column (1.0 X 2.0 cm) and was measured by a radioimmunoassay (RIA). Plasma (5-10 ml) was diluted with an equal volume of 10 mmol/l sodium phosphate buffer, pH 7.4, containing 0.9% NaCl (PBS) and was applied to an immunoaffinity column from which glandular kallikrein was eluted with 3 mol/l NaSCN (20 ml). The enzymic fraction was concentrated with an Amicon PM 10 filter and dialyzed against PBS. The final recovery of the enzyme was 51.6 +/- 1.6% (mean +/- SD), determined by using [125I]kallikrein. The usable range of the standard curve covered 2.5-100 ng/tube. The coefficient of variation within the series was 5.9%, and the coefficient of variation between the series was 7.6%. In healthy controls (n = 25), the plasma content of glandular kallikrein was 1.36 +/- 0.39 ng/ml. In patients with acute pancreatitis (n = 6), the plasma concentration was 8.02 +/- 6.15 ng/ml, significantly different from the control group (p less than 0.01).

Clinical utility of measuring free thyroxin and free triiodothyronine in serum of critically ill patients by ultrafiltration

Free thyroxin (FT4) measurements by ultrafiltration were compared with results obtained by equilibrium dialysis and commercial RIA methods. In a group of critically ill patients, the mean +/- 2 SD FT4 value by ultrafiltration (26.5 +/- 21.4 ng/L) was higher than in the healthy reference population (19.3 +/- 9.8 ng/L, p less than 0.0001), and correlated well with equilibrium dialysis (23.8 +/- 20 ng/L, r = 0.87). By a two-step RIA method (Clinical Assays), the FT4 value was greater in the critically ill (14.7 +/- 9.6 ng/L) than in the reference population (12.8 +/- 5 ng/L, p less than 0.001) and was also correlated with ultrafiltration results (r = 0.71). FT4 values for the ill patients were lower than for the reference population in two one-step RIA methods (Clinical Assays: 8.6 +/- 7.1 ng/L; Corning Medical: 12.7 +/- 9.4 ng/L), neither of which gave results correlated with ultrafiltration (r = 0.16 and 0.22, respectively). The concentration of free triiodothyronine (FT3), also measured by ultrafiltration, was 4.5 +/- 2.2 ng/L in healthy subjects, 12.5 +/- 14.2 ng/L in hyperthyroidism, 1.7 +/- 2.0 ng/L in hypothyroidism, 2.2 +/- 1.9 ng/L in the critically ill subjects, and 3.8 +/- 0.9 ng/L in pregnancy. Thus, FT4 and FT3 measured by ultrafiltration accurately affects assessment of the thyroid status of the patient except in critical illnesses in which FT3 values are indistinguishable from those in hypothyroidism.

Plasma prekallikrein, functional kallikrein inhibition, antithrombin III, plasminogen, kallikrein activity and proenzyme functional inhibition index in 172 acute ill surgical patients on admission

The present study was performed in order to study disturbances in plasma proteolysis in acute ill surgical patients on admission. The paper describes the distribution of values for plasma PKK, KKI, AT III, Plg, KK and PFI-index. In early stages of the disease process rather minimal information can be obtained by these data in addition to clinical examination. The study indicates that chromogenic peptide substrate assays should be reserved for surgical patients treated in the intensive care unit.

Evidence that changes in fibrinogen quality during acute phase reactions are of major importance for the amount of heparin precipitable fraction (HPF)

The influence of qualitative and quantitative changes in plasma fibrinogen upon the amount of heparin precipitable fraction (HPF), obtained during the course of acute disease states, were examined. Whereas fibrinogen in plasma includes 3 species of different molecular weights (HMW, LMW, LMW'), fibrinogen in HPF, from normal as well as from "acute phase" plasma, consisted almost exclusively of HMW-fibrinogen (3% SDS-PAGE). Sub-unit chain electrophoresis (10% PAGE-SDS and two-dimensional electrophoresis) did not disclose any signs of abnormalities in the fibrinogen precipitated in HPF. Studies on patients revealed that the composition of plasma fibrinogen changed (increased HMW) during the course of acute myocardial infarction and following hip operations, and indicated that the amount of HPF was governed by the relative amount of HMW-fibrinogen as well total fibrinogen. This assumption was strengthened by quantitating the amount of HPF obtained after addition of highly purified HMW and LMW fibrinogen to normal and "acute phase" plasma. It is concluded that fibrinogen quality (per cent HMW or HMW/LMW ratio) is of major importance for the amount of HPF, thereby explaining some of the HPF-variations seen during the course of acute diseases.

Evaluation of the Coulter S-Plus IV three-part differential in an acute care hospital

An evaluation of the three-part white cell differential count on the Coulter S-Plus IV was carried out in a 500-bed acute care hospital. Automated counts were compared with manual differential counts over a seven-month period. The S-Plus IV categorizes cells by volume after treatment with diluent and lysing solution. The three categories are labeled lymphocyte, mononuclear, and granulocyte, and, in normal samples, these correspond with lymphocytes, monocytes, and neutrophils. Eosinophils are counted either as mononuclear cells or granulocytes. Automated counts agree well with manual counts for the lymphocyte and granulocyte categories. Agreement is poor for the mononuclear category; this is likely due to the imprecision of the manual differential count. The S-Plus IV accurately classifies most samples as normal or abnormal. When all parameters of the hematology panel were evaluated, the false negative rate was less than 1%. Sixteen percent of results from the S-Plus IV were flagged, and 79% of these indicated an abnormality. False positive flags are usually due to a failure to adequately segregate mononuclear cells from granulocytes. Most commonly encountered abnormalities and hematologic disorders have abnormal three-part differential counts. The authors think the three-part differential cannot totally replace the manual differential but can decrease the number of repeat manual differentials on inpatients. It also offers quality control features useful to the hematology laboratory.

Evidence for differentiation of human leukemic blood cells in diffusion chamber culture

Peripheral blood cells of 21 patients with different forms of acute leukemia were cultured in diffusion chambers (5 x 10(5) cells/chamber) implanted intraperitoneally in 650 R preirradiated host mice over a period of up to 21 days. In patients with acute myeloid leukemia (AML), acute erythroleukemia (AEL), or acute myelomonocytic leukemia (AMMoL), the total number of cells which developed during this culture period exceeded the implanted value and also the values for normal peripheral blood cells from ten controls. In acute undifferentiated leukemia (AUL), two out of six patients showed considerable growth whereas the others, and also two patients with acute lymphoid leukemia (ALL), had poor growth. Differential counts revealed that the rise in total cells was due mainly to proliferation of blast cells and formation of granulopoietic cells. The latter exceeded the numbers from normal peripheral blood cells in 9 out of 13 patients with AML, AEL, or AMMoL and in 2 out of 6 patients with ALL. The production of granulopoiesis was not restricted to proliferating cells, but included mature cells which were of abnormal morphology in some cases. From the amount of granulopoiesis and the time of its development it was assumed that they were at least partly derived from leukemic blast cells. Chromosome analyses to decide whether the granulopoietic cells were of leukemic or normal cell origin are in progress.