Excretory/secretory (E/S) antigen derived from second-stage larvae of Toxocara canis maintained in defined medium in vitro has been well established worldwide for the immunodiagnosis of human toxocarosis by enzyme-linked immunosorbent assay. Such an enzyme-linked immunosorbent assay, based on the detection of human anti-T. canis (E/S antigen) serum immunoglobulin G, has recently been commercialized by Biokema-Affinity Products (Crissier-Lausanne, Switzerland). This commercial test kit was evaluated with regard to its application in a routine diagnostic laboratory and the reliability of the results. Of 78 patients with suspected clinical toxocarosis, 71 had anti-T. canis antibodies (positive serological result) corresponding to a diagnostic sensitivity of 91%; 14% of serum samples (n = 199) from patients with protozoan or with helminthic infections also showed positive reactions mainly related to infections with Trichinella, Strongyloides, and Fasciola species. An epidemiological study with 1,000 serum samples from randomly selected healthy blood donors and children in Switzerland demonstrated a seroprevalence of 2.7%. The test kit under evaluation had an overall diagnostic sensitivity of 91% and a relative specificity of 86%, the latter being related to some protozoan and helminthic infections. Because of the scarcity of such infections, potential cross-reactivity does not play a major role under the conditions found in the middle part of Europe. In conclusion, the application of the test kit provided for use in this study can be recommended for routine diagnostic use.

No abstract

The influence of cysteine (Cys) on mucosal uptake of 75Se-labeled selenite in sheep midjejunum was investigated using a short-term uptake technique. L-Cys (concn.: 1.0 mmol/L) significantly stimulated uptake of Se from selenite (concn.: 10 mumols/L). The stimulatory effect of L-Cys on mucosal uptake of Se from selenite was Na(+)- and pH-dependent. In the absence of Na+, or at an acidic pH (5.0), the stimulatory effect of L-Cys was abolished. L-alanine and L-lysine, but not L-glutamic acid inhibited uptake of Se from selenite in the presence of L-Cys. Preincubation of mucosal preparations with 10 mmol/L L-Cys produced enhanced mucosal uptake of Se from selenite. It is concluded from these results that L-Cys stimulates absorption of Se from selenite probably by generation of selenodicysteine and maybe cysteine selenopersulfide that are subsequently transported across the intestinal brush border membrane by Na(+)-dependent amino acid carriers. Furthermore, intracellular generation of selenodicysteine might contribute to the uptake of Se from selenite by maintaining the concentration gradient for diffusive uptake of selenite.

The influence of oxalate on mucosal sulphate, selenate and selenite uptake in the sheep midjejunum was investigated. Oxalate significantly inhibited sulphate and selenate uptake, whereas mucosal uptake of selenite and L-leucine was not affected. Thus, the effect of oxalate on sulphate and selenate uptake appears to be specific. Besides oxalate, the dicarboxylate anions oxaloacetate and fumarate also significantly reduced mucosal sulphate uptake.The results suggest that oxalate and dicarboxylate anions with a similar structure competitively inhibit mucosal sulphate and selenate uptake by sheep mid-jejunum.

Zusammenfassung Es wurde die Natrium‐, pH‐ und Konzentrationsabhängigkeit der Aufnahme von L‐Leucin, L‐Glutaminsäure und L‐Lysin durch den Bürstensaum in das Duodenalepithel von Schafen untersucht. Dabei konnte für die L‐Leucin‐Aufnahme eine deutliche Natriumabhängigkeit nachgewiesen werden, während sich für die Aufnahme der beiden anderen Aminosäuren eine Natriumabhängigkeit lediglich andeutete. Die L‐Leucin‐Aufnahme war bei pH 4, 5,5 und 7 etwa gleich. Dagegen war die L‐Lysin‐Aufnahme bei pH 4 niedriger als bei pH 5,5 und 7, während sich für die L‐Glutaminsäure‐Aufnahme bei pH 4 höhere Werte ergaben als bei pH 7. L‐Leucin und L‐Glutaminsäure wurden bei pH 4 über einen saturablen Mechanismus in das Duodenalepithel aufgenommen. Für L‐Lysin schien dies nicht der Fall zu sein. Aus den Ergebnissen wird geschlossen, daß neutrale und saure Aminosäuren unter physiologischen pH‐Verhältnissen (pH 4) aus dem Schafduodenum aktiv resorbiert werden.