The bait-lamina test: General aspects, applications and perspectives.

A general introduction of the bait-lamina test has been made in this article. This article has an introductional character for other articles dealing with the bait-lamina test method and gives the experimental data. The test was first introduced by Törne in 1990 to measure the biological activity of soil. It enables the monitoring of biotic (microbial and zootic) processes in the soil within a short period of time, and detailed investigations. The test system is based on visual assessment of feeding on small portions of thin laminated bait substrate exposed to edaphic processes. The test system has found its application mainly in Germany but in the meanwhile also in Portugal, Switzerland and in the Netherlands in laboratories of soil ecology and soil ecotoxicology. At present there are only few publications in the international literature, but the interest in this method is growing. During the past years two workshops on the subject have been organized in Germany to summarize experiences with and to evaluate the test system and optimize the standard procedure.

Commercial wrist extensor orthoses: a descriptive study of use and preference in patients with rheumatoid arthritis.

OBJECTIVE: To describe patients' functional uses of 3 commercial wrist orthoses, to describe patients' preference patterns for the orthoses, and to clarify orthotic attributes that are viewed positively and negatively. METHODS: Using a cross-over design, 42 patients with definite rheumatoid arthritis used each of 3 commercial orthoses for one week. There was a one-week wash-out between each week of use. At the end of the study, private semi-structured interviews were conducted with each participant. Data from close-ended questions were tabulated. Open-ended data were analyzed using qualitative methods. RESULTS: Patients reported that the 3 commercial wrist orthoses reduced wrist pain similarly, but that comfort and a sense of security during functional tasks were only found if the orthoses were comfortable and well-fitting. Most subjects preferred the padded, short forearm orthosis, though a small number found it uncomfortably warm, and many complained that it was difficult to use when wearing long-sleeved garments. Common complaints about the two elastic orthoses included chafing at the thumb webspace and chafing at the proximal closures. Longer forearm length was often perceived as providing unnecessarily high levels of wrist support. CONCLUSIONS: No single orthosis suited all subjects. Satisfaction with an orthosis appears to be based not only on its therapeutic effect, but also the comfort and ease of its use. To maximize patient satisfaction and improve the likelihood of appropriate fit and comfort, several styles of commercial orthoses should be available. The current trend toward restricted clinic stocks appears contrary to both therapeutic goals and patient satisfaction.

Terrestrial model food chain and environmental chemicals. I. Transfer of sodium [14C]pentachlorophenate between springtails and carabids.

A model soil food chain of a ruderal ecosystem has been constructed in order to study the uptake, transfer, and accumulation of [14C]pentachlorophenate (PCP-Na). The model was based on three food levels, viz. baker's yeast, collembola, and carabid beetles, and the contaminant chemical introduced was via initial food. Continuous exposure of the organisms to the test chemical resulted in a significant uptake and transfer of radiocarbon into the food chain elements. Bioaccumulation of radiocarbon in the body tissues of the organisms was low, as large amounts taken up were quickly eliminated through the excrements. The radiocarbon level of prey animals was about 100 times higher than that of their predators, but there was only small difference in concentration between collembolas and yeast. This was probably because of a faster excretion of the chemical by the beetles than by the collembolas. During the test period no conversion of [14C]PCP-Na took place in the yeast, but the collembolas and beetles metabolized 50 and 59%, respectively. Criteria are proposed for successful implementation of food chain models.

Environmental fate and distribution of sodium [14C] pentachlorophenate in a section of urban wasteland ecosystem.

An urban terrestrial microecosystem has been used under outdoor conditions to study the transfer of chemical residues within the system components. The microecosystem consisted of soil monoliths obtained from a site with an established vegetation cover dominated by goldenrod, Solidago gigantea. The microecosystem contained integrated food chain elements composed of primary producers, herbivores and carnivores. The system was stocked with indicator insect species, snails (Cepaea nemoralis) and earthworms (Allolobophora caliginosa), captured from the original site. Evaluation of the system was made using radiolabelled sodium pentachlorophenate (PCP-Na) which was applied as a single application at an equivalent rate of 5 kg ha-1. The mass balance revealed that, after 131 days, in the autumn, and after 222 days, in the winter, that 43 and 39% radiocarbon, respectively, was recoverable from the microecosystem. The unaccounted radiocarbon was very probably removed through volatilization and photomineralization of the compound. PCP residues on foliage decreased rapidly, 50% of which were metabolised within 15 days. Most of the radiocarbon remaining in the system after 131 days was in the top soil and plant litter, transmitted mainly through washing off by rain and leaf litter fall. There was a variation in the uptake of PCP-Na residues in the food chain organisms, where the total radiocarbon concentrations during the first 19 days of exposure ranged, e.g. in snails, from 3 to 0.6 micrograms g-1, in springtails from 5 to 105; in beetles (Amara fusca) from 3 to 1, in spiders from 13 to 11, and in harvestman from 31 to 77 micrograms g-1. The ecological magnification indices (EM) of all the organisms with respect to their main food source, i.e. plant litter, demonstrated no bioconcentration effects. This is attributed to the metabolism of PCP-Na by the organisms and its rapid excretion. The urban wasteland ecosystem contained in outdoor lysimeters employed as a model gives valuable information and has considerable value in predicting the ecological fate of industrial chemicals.

Model for individual substitution of immunoglobulins after membrane plasma separation.

Patients who undergo extensive plasma exchanges using albumin replacement may be more susceptible to infection because they develop significant hypogammaglobulinemia. Substitution of IgG in these patients could be beneficial. A model to calculate the individual amount of IgG required is described. The course of IgG during chronic intermittent membrane plasma separation (MPS) therapy was simulated using an one-pool model. Three modes of substitution were considered for their efficacy: infusion after MPS infusion after discarding an equivalent plasma quantity after termination of MPS, and plasma exchange at the end of MPS against an IgG solution. Mode B was shown to be most economical and was subsequently used to check the validity of the substitution model in a prospective test. The difference between predicted and measured IgG levels was 5% both for simulations from one MPS to the next and for the long-term prediction. The data prove that replacement of IgG after plasma separation is practicable. The substitution model allows to fix in advance any plasma limit value for indication and target of the substitution therapy. Thus it permits to give therapeutic recommendations for individual IgG substitution therapy of secondary antibody deficiency after MPS.

Nomograms for the prediction of patient's plasma volume in plasma exchange therapy from height, weight, and hematocrit.

The knowledge of plasma volume (PV) is a basic requirement for the standardization of plasma exchange therapy. PV has to be determined by calculation, as the measurement of PV before every plasma exchange is too cost- and time consuming. A known correlation with measured values results from calculation of plasma volume by means of patient's height and weight. But the present equations are only reliable at normal hematocrit. For this reason we modified the Retzlaff-equations and compared the validity of plasma volume predictions, calculated by these and own equations, with plasma volume measured by the 51Cr-method in 59 patients with pathological hematocrit. The correlation coefficient was 0.82 for men and 0.81 for women (2 0.001) with the modified Retzlaff-equations. On the average the relative error was -1.5% for all and 2.8% for fat and thin men. No significant improvement of accuracy was achieved with other equations. Thus, plasma volume can accurately be calculated from height, weight, and hematocrit with our modified Retzlaff-equations in patients with pathological hematocrit, even if they are very fat or thin. Nomograms for men and women were constructed in order to facilitate the calculation.