20 research outputs found
Allergen avoidance in the home environment : a laboratory evaluation of measures against mite, fungal and cat allergens
No full text
Cloning, expression and site-directed mutagenesis of the gene encoding horse liver alcohol dehydrogenase in E. coli
No full textIndoor air quality and physical independence : an innovative view on healthy dwellings for individuals with chronic lung disease
No full textXIV+130hlm.;24c
Allergen Der p1 and guanine production of house dust mites Dermatophagoides pteronyssinus in a semi-natural environment
No full textHygienic limits for mite allergen exposure are established on empirical grounds. The correlation of mite numbers, guanine content and allergen Der p 1 or group 1 content in house dust is sometimes obscure. The aim of this study is to determine the ratio of newly produced allergen Der p 1 and guanine per mite per day in a controlled environment.
In a semi-natural test system, house dust mites (D. pteronyssinus) were incubated on soiled carpets at 75% and 80% relative humidity (rH) for 2,4, 6, and 8 weeks. Guanine and Der p 1 production per mite per day was calculated by determination of the guanine and allergen Der p 1 content of the mite substrates, and integration of the counted number of live mites per incubation period.
At 75% rH, mean Der p 1 production per mite per day was 0.5 ± 0.1 ng. Guanine production amounted to 15 ± 4 ng per mite per day. The allergen production was lower than expected from literature data, which may be related with a different diet. The ratio between the geometric means of Der p 1 and guanine in these experiments is 1:50 on the average. This is remarkably lower than the ratio between the internationally accepted hygienic limits in house dust for these compounds (1:300). Increasing humidity to 80% rH did not result in significant production changes.
Differences in production and degradation of allergens and guanine, under different indoor conditions will account for the deviation in their mutual correlations, thus influencing the usefulness of these parameters in exposure assessments and decreasing the validity of
generalized hygienic limits in individual cases
Capillary zone electrophoresis of proteins with a dynamic surfactant coating: influence of a voltage gradient on the separation efficiency
No full textIn capillary zone electrophoresis of proteins, the adsorption of the proteins on the capillary wall is a considerable problem that seriously impairs the sepn. efficiency. The use of a dynamic surfactant coating is a possible way to diminish this adsorption. Highly efficient sepns. were achieved with a cationic fluorinated buffer additive as a dynamic surfactant coating in untreated fused-silica capillaries at neutral pH. The influence of a voltage gradient on the sepn. efficiency is discussed and a simple relationship is presented to calc. effective mobilities under voltage gradient condition
Whole brain spheroid cultures as a model to study the development of nitric oxide synthase-guanylate cyclase signal transduction
No full textWhole brain spheroids provide a suitable model to study neurodevelopment. In the literature a role for the nitric oxide (NO)-cyclic guanosine 3',5'-monophosphate (cGMP) signalling pathway during development has frequently been suggested. In this study we investigated whether functional cGMP pathways were present in differentiated spheroids. In 3-week-old spheroids soluble guanylate cyclase was stimulated with N-methyl D-aspartic acid or sodium nitroprusside (NO donor). The results showed that the NO synthase-cGMP pathway is present in the culture system. Soluble guanylate cyclase-dependent cGMP formation was found in NO synthase containing neurons, in neurons of the GABAergic, glutamatergic and cholinergic system, and in astroglia and oligodendroglia. Activation of particulate guanylate cyclase by atrial natriuretic peptide also triggered an increase in cGMP production. Particulate guanylate cyclase was found in astroglia and in microglia as well as in glutamic acid decarboxylase and calbindin containing structures and neuronal NO synthase containing neurons. Chronic inhibition of NO synthase during culture development had no effect on soluble or particulate guanylate cyclase functioning, Similarly, inhibition of soluble guanylate cyclase during culture development did not have any effect on NO synthase and particulate guanylate cyclase functioning. It is concluded that NO synthase and both soluble and particulate guanylate cyclase are present in whole brain spheroid cultures and that their activity can be influenced by several stimuli. The spheroid culture system constitutes a suitable model to study the NO-cGMP pathway during brain development in mammals. (C) 2000 Elsevier Science B.V. All rights reserve
