Wageningen Evaluating Programmes for Analytical Laboratories (WEPAL).

The paper describes three of the Wageningen Evaluating Programmes for Analytical Laboratories (WEPAL). These include the analyses of numerous compounds and elements and different parameters such as inorganic chemical composition, organic matter, polycyclic hydrocarbons (PAH), polychlorinated biphenyls (PCB), organochlorine pesticides, some herbicides, heavy metals, particle size, and so on in soil, sediment, compost, manure, and sludge. One programme includes the analysis of inorganic chemical composition, nutritional values, and selected vitamins and amino acids in plant samples.

Assaying tumor necrosis factor concentrations in human serum. A WHO International Collaborative study.

A collaborative study involving several international research groups was conducted in order to test the validity and reproducibility of tumor necrosis factor-alpha (TNF) measurements in serum. 58 serum samples, nine of them spiked with recombinant human TNF, were aliquoted and distributed blindly to 11 different laboratories. 20 samples were obtained from cerebral malaria patients, 20 from septic shock patients, eight from patients with rheumatoid arthritis and ten from normal blood donors.

Protodyne: an immunostimulatory protein component, prepared from gram-positive Bacillus subtilis.

A protein component derived from bacterial protoplasm, called Protodyne, increases the non-specific resistance to infections by bacteria and viruses. Here we show that Protodyne can be prepared not only from Gram-negative bacteria, but also from Gram-positive bacilli. Several preparations of Protodyne, prepared from Bacillus subtilis by phenol extraction or by ammonium sulfate precipitation, were evaluated for immunomodulatory activities in a variety of assays.

Attempts to manipulate specific responses to induce resistance to Schistosoma mansoni in Kenyan baboons (Papio anubis).

Attempts were made to manipulate specific responses of baboons to protect them from infection with Schistosoma mansoni. In Experiment 1, eosinophilia was induced in naive baboons with Trichinella spiralis larvae given intravenously before intraperitoneal injection of globulin fractions from S. mansoni-infected baboon sera and subsequent percutaneous exposure to S.

Observations on possible immunity to reinfection among Kenyan schoolchildren after treatment for Schistosoma mansoni.

In February 1977, 306 out of 409 six- to 16-year-old Kenyan schoolchildren were found to be infected with Schistosoma mansoni. Prevalence and intensity were directly related to age and indirectly to the distance between the child's home and the transmission site, but were not related to the child's sex. Most children were treated with hycanthone in July 1977.

Heat-labile and heat-stable anti-schistosomular antibodies in Kenyan schoolchildren infected with Schistosoma mansoni.

Two in vitro cytotoxicity assays using 51Cr-labelled Schistosoma mansoni schistosomula were performed on serum samples collected from 91 schoolchildren infected with S. mansoni from Machakos District, Kenya. One assay, which is believed to detect IgE/antigen complexes, uses unheated serum and human monocytes; the other, believed to detect IgG antibodies, uses heat-inactivated serum and unpurified peripheral blood leucocytes.

Functional studies on purified eosinophils and neutrophils from patients with Schistosoma mansoni infections.

Unpurified peripheral blood leucocytes or purified eosinophils and neutrophils from patients with schistosomiasis and from normal individuals were compared for their ability to interact with antibody coated schistosomula of Schistosoma mansoni. There was no difference in the ability of buffy coat cells or neutrophils from patients and from normal individuals to mediate antibody-dependent 51Cr release from labelled schistosomula. However, eosinophils from patients were significantly better than those from normal individuals in causing antibody-dependent 51Cr release.

Immunologic aspects of renal lesions associated with malaria.

Studies on experimental models of infections and observations in man indicate that immune complexes (IC) play an important role in the pathogenesis of nephropathies associated with malaria. All present evidence suggests that IC preformed in circulation localize in the glomeruli and initiate the lesions. In acute lesions, typical of falciparum infections in man, the depositions of IC are found quite soon after infection; glomerular injury is reversible, and these cases respond well to antimalarial therapy.

Experimental renal disease due to schistosomiasis.

Although there is a marked variability in the development of renal lesions among individual animal models of schistosomal infections, much has been learned about the mechanisms leading to renal injury. The lesions in S. mansoni and S.

Rheumatoid arthritis in Kenya. II. Serological observations.

Sera from 48 Kenyan Africans with rheumatoid arthritis, 43 patients with other diseases, and 98 blood donors were tested for the presence of rheumatoid factor by latex fixation tests using human European, human African, and rabbit immunoglobulin, and a sheep cell haemagglutination test. In the patients with rheumatoid arthritis the frequency of rheumatoid factor was comparable to that reported in series from Europe and the USA, thus differing from the findings in West Africa. In the control patients and blood donors a high frequency of positive tests for rheumatoid factor was found; a similar result has been obtained from population studies in other African countries.

Rheumatoid arthritis in Kenya. I. Clinical observations.

76 Kenyan Africans with classical or definite rheumatoid arthritis are described. Their age, sex ratio, and pattern of joint involvement closely resembled that seen in Europe and the USA and differed from that described in West Africa and rural South Africa. However, they showed a marked lack of systemic nonarticular complications, with relatively little functional incapacity.

Comparison of the ability of eosinophils and neutrophils, and of eosinophils from patients with S. mansoni infection and normal individuals, to mediate in vitro damage to schistosomula of S. mansoni.

A reliable and reproducible method that produces separate fractions of pure eosinophils and neutrophils from normal peripheral blood was described. The interaction of eosinophils and neutrophils with antibody coated schistosomula was examined in vitro. Neutrophils were highly active in the 51Cr release assay and most formed rosettes with antibody coated red cells, but they adhered poorly to schistosomula and did not kill the organisms.

The mechansim of antibody-dependent, eosinophil-mediated damage to schistosomula of Schistosoma mansoni in vitro: a study by phase-contrast and electron microscopy.

A characteristic sequence of events has been identified by phase-contrast and electron microscopy during antibody-dependent, eosinophil-mediated damage to schistosomula of Schistosoma mansoni in vitro. Human eosinophils initially adhere to the intact schistosomulum and then, in the presence of antibody, flatten and spread very intimately over the parasite's surface. Subsequently, dense material similar to the contents of the lysosomal granules of the eosinophils appears in the extracellular space between the eosinophil and the schistosomulum, probably following fusion of the granules with the plasma membrane of the cell.

Cytotoxicity of human and baboon mononuclear phagocytes against schistosomula in vitro: induction by immune complexes containing IgE and Schistosoma mansoni antigens.

Normal human blood monocytes, pre-incubated at 37 degrees C with sera from patients infected with Schistosoma mansoni, strongly adhered to S. mansoni schistosomula in vitro, whereas no significant adherence was induced by sera from uninfected individuals. Comparable adherence occurred with normal baboon blood monocytes or peritoneal macrophages when these cells were incubated with sera from S.

Schistosoma mansoni in the Kenyan baboon (Papio anubis): the development and predictability of resistance to homologous challenge.

Groups of baboons were exposed to primary infections of either 500 or 2,000 Schistosoma mansoni cercariae per baboon (c.p.b.

Kidney lesions in baboons infected with Schistosoma mansoni.

Glomerular lesions in baboons (Papio anubis) infected with different dosage regimes of Schistosoma mansoni were studied by immunofluorescence and light microscopy on kidney sections and by countercurrent immunoelectrophoresis on kidney homogenates and tissue eluates. Mild lesions, characterized by focal and segmental deposits of immune complexes, developed in sixty-two out of 103 baboons, irrespective of the intensity and duration of the infection. Severe, diffuse lesions developed in six baboons after prolonged and heavy infections.

Eosinophilia in Kenyan baboons (Papio anubis) induced by Trichinella spiralis and Schistosoma mansoni.

High primary doses of Trichinella spiralis administered orally to Kenyan baboons (Papio anubis) induced a marked but unpredictable eosinophilia which started 2--3 weeks after infection and persisted as erratic waves for at least 6 months. Low primary oral doses induced no eosinophilia but a later, high challenge gave an accelerated eosinophilic response, although the peak was lower than in high primary infection. Intravenous injection of infective T.

Antibody-dependent, eosinophil-mediated damage to 51Cr-labeled schistosomula of Schistosoma mansoni: effect of metabolic inhibitors and other agents which alter cell function.

The effect of drugs known to inhibit different metabolic pathways or cell functions on antibody-dependent, eosinophil-mediated damage to schistosomula was determined. Eosinophil-mediated damage was completely inhibited by cytochalasin B, inhibitors of glycolysis, aminophylline, and treatment of cells with diazotized sulfanilic acid and tosyl-lysyl-chloromethyl ketone. The effects of cytochalasin and 2-deoxyglucose were reversible.