Although complement activation and deposition have been associated with a variety of glomerulopathies, the pathogenic mechanisms by which complement directly mediates renal injury remain to be fully elucidated. Renal parenchymal tissues express a limited repertoire of receptors that directly bind activated complement proteins. We report the renal expression of the receptor for the C3 cleavage product C3a, a member of the anaphylatoxin family. C3aR is highly expressed in normal human and murine kidney, as demonstrated by immunohistochemistry and in situ hybridization. Its distribution is limited to epithelial cells only, as glomerular endothelial and mesangial cells showed no evidence of C3aR expression. The C3aR is also expressed by primary renal proximal tubular epithelial cells in vitro as demonstrated by FACS, Western blot, and RT-PCR. In vitro C3aR is functional in terms of its capacity to bind 125I-labeled C3a and generate inositol triphosphate. Finally, using microarray analysis, four novel genes were identified and confirmed as transcriptionally regulated by C3aR activation in proximal tubular cells. These studies define a new pathway by which complement activation may directly modulate the renal response to immunologic injury.

The performance characteristics of an immunoradiometric assay for bone alkaline phosphatase mass concentration in human sera are reported.Within-run imprecision (n = 20) was 12.1% (x = 7.8 μ §/\) and 3.6% (x = 22.8 Mg/1), between-day imprecision (n = 8) was 10.1% (X = 20.3 μ£/1) and 2.8% (x = 84.3 μ §/1). There was a linear relationship between the concentrations of the Standards employed and the counts per minute up to 120 μ^Ι. The detection limit was 0.3In 102 apparently healthy persons (51 males and 51 females; r nge of age: 18-56 years) the following reference intervals were established: 3.8-21.3 μg/l (males) and 3.4-15.0 μg/l (females).We compared the values obtained using the immunoassay with those obtained by precipitating of bone alkaline phosphatase with wheat-germ lectin (alkaline phosphatase activity concentration was determined at + 25 °C by the optimized Standard method according to the Recommendations of the German Society for Clinical Chemistry). For the reference individuals the relationship between the results pf the two methods is given by the following regression equation: Bone alkaline phosphatase activity concentration [U/l] = 14.81 + 3.28 X bone alkaline phosphatase mass concentration [jigft] (r = + 0.783). In 89 sera from 32 patients before and after renal transplantation (r nge of bone alkaline phosphatase mass concentration: 2-39 μg/l) comparison between the two methods yielded a linear correlation coefficient of r = + 0.886.Of 20 sera taken from patients suffering from various hepatobiliary diseases (r nge of total alkaline phosphatase activity concentration: 217-3270 U/l) 18 (90%) showed a bone alkaline phosphatase mass concentration above the upper reference limit (r nge of bone alkaline phosphatase mass concentration: 16-206 μg/l). This is probably due to a cross-reactivity of the antibodies employed for the immunoassay of bone alkaline phosphatase with liver alkaline phosphatase in plasma. It is concluded that an increased release of liver alkaline phosphatase into serum leads to falsely high values for bone alkaline phosphatase mass concentration, severely limiting the diagnostic validity of the test in such cases.

Aus den Untersuchungen folgt, daß Steroide und ihre Plasmabindung in Blut oder Plasma gegenüber den meisten üblichen äußeren Einflüssen relativ stabil sind und auch aus weniger sorgfältig behandelten Proben (Postversänd) in der Regel noch ausreichend zuverlässig analysiert werden können. Influence of storage and temperature on steroid analysis in plasma and blood Summary:In the analysis of steroid Jiormones careful attention is usually paid to blood collection and plasma storage. However, the appropriate care of samples cannot always be assured in routine work with steroids. Therefore, the stäbility of Cortisol, aldosterone, 17-hydroxyprogesterone, testosterone, androstenedione, dehydroepiandrosteronesulphate, oestrone, oestradiol, sex hormone binding globulin (SHBG) and, the binding of testosterone and cortisol to plasma proteins in blood and plasma were studied before and after various handling prpcedures, Ten cycles of alternate freezing and thawing of plasma did not significantly affect the levels of the steroids or their plasma binding. The greatest differences, compared with controls, were seen for aldosterone (-6.2%) and oestradiol (-5.3%). Plasma storage at -28 °C was hardly superior to a 4 days storage at 4 °C (refrigera-

' Summary: The new photometric assay described by Fickenscher et al. (Thromb. Haemostas. 65 (1991) 535-540) j for the determination of factor XIII facilitates the diagnosis of factor XIII deficiency. In spite of easy handling, this | test should be used critically. Patients with hyperfibrinogenaemia showed factor XIII activities of less than 20%, i whereas with an optimized assay we found normal factor XIII values. Also, the use of a fixed period of incubation for the analysis is questionable, because the period of constant reaction rate occurs earlier and is shorter with high factor XIII activities and later and longer with low factor XIII activities. A linear relation between factor XIII activity and signal only exists up to 80% of activity.In some plasma samples from patients with hyperfibrinogenaemia the factor XIII determination actually shows decreased values for factor ΧΙΠ. During the reaction, a fibrin clot is formed. The resulting turbidity simulates an increase in absorbance so that NADH consumption is apparently decreased. In six patients with hyperfibrinogenaemia (8.1-9.4 g/l), a factor XIII activity of 26 U/l or less was determined. Using 50 μΐ instead of 100 μΐ sample volume, 50% (3/6) of the patients showed a normal factor XIII activity (80-96 U/l), whereas 50% (3/6) values of 6-15 U/l were found. In our modified assay we measured normal factor XIII activities (72-151 U/l) in all 6 patients. The procedure is optimized by reducing the sample voluine from 100 μΐ to 50 μΐ. The concentration of the fibrin aggregation inhibitor is raised from 0.5 g/l to 1.0 g/l in the test solution, and the period of constant reaction rate is used for the determination. Enzyme activity is expressed in U/l (37 °C). Optimized in this way, the assay shows a linear relationship between the decrease of absorbance and factor XIII activity up to more than 128 U/l, corresponding to 140%. Plasma samples with high concentrations of fibrinogen can be analysed without problems. Precision was 2.3% in series and 2.8% from day to day, using a control plasma with 81 U/l; for a control plasma with 35 U/l, the respective values were 4.9% and 5.8%. In apparently healthy 100 pefsons a reference interval of factor XIII activity was established from 66 to 142 U/l or 73 to 155%.