Plasma levels of androgens and 17 alpha-OH-progesterone as an index of the adequacy of treatment in congenital adrenal hyperplasia

Plasma levels of dehydroepiandrosterone-sulfate (DHEA-S), dehydroepiandrosterone (DHEA), delta 4-androstenedione (delta 4), testosterone and 17 alpha-OH-progesterone (17-OH-P) were studied in 58 samples collected in 18 patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency, during long-term ambulatory treatment with hydrocortisone. At each visit the patients were classified as being either in good control (GC) or in poor control (PC), based on well-defined clinical, auxological and biochemical criteria. The results were analyzed in relation to the degree of control and to chronological age (CA), bone age (BA), body surface (BS) and pubertal development. The most clear distinction between the children with GC and those with PC is found for DHEA-S (p less than 0.001 for BA). The majority of the DHEA-S values in the children with GC are closely grouped and significantly below the normal limits for CA, BA, BS and pubertal stage (p less than 0.001). In contrast, the PC children have wide-spread values, most of them being within or above the normal limits. The difference between GC and PC is also significant for testosterone (p less than 0.01) and delta 4 (p less than 0.05), but not for DHEA. Of the five steroids studied, DHEA-S is the most specific, whereas testosterone is the most sensitive and especially useful in girls and in prepubertal boys. delta 4 and 17-OH-P are almost as sensitive as DHEA-S, but they are less specific. DHEA is the less valid criterium.     

“Organized stress” for robust scale-up of intensified production process with fed-batch seed bioreactor

Process intensification has been widely used for many years in the mammalian biomanufacturing industry to increase productivity, agility and flexibility while reducing production costs. The most commonly used intensified processes are operated using a perfusion or fed-batch seed bioreactor enabling a higher than usual seeding density in the fed-batch production bioreactor. Hence, as part of the growth phase is shifted to the seed bioreactor, there is a lower split ratio, which increases the criticality of the seed bioreactor and could impact production performance. Therefore, such intensified processes should be designed and characterized for robust process scale-up. This research work is focused on intensified processes with high seeding density inoculated from seed bioreactor in fed-batch mode. The impact of the feeding strategy and specific power input (P/V) in the seed bioreactor and on the production step with two different cell lines (CL1 and CL2) producing two different monoclonal antibodies was investigated. Cell culture performance in the production bioreactor has been improved due to more stressful conditions for the cells in the seed bioreactor and the impact of the production bioreactor P/V on the production performance was limited. This is the first reported study highlighting a positive impact of cellular stress in seed bioreactors on intensified production bioreactor with the introduction of the “organized stress” concept.     

Stimulus dependent neural correlations in the auditory midbrain of the grassfrog (Rana temporaria L.)

Few-unit recordings were obtained using metal microelectrodes. Separation into single-unit spike trains was based on differences in spike amplitude and spike waveform. For that purpose a hardware microprocessor based spike waveform analyser was designed and built. Spikes are filtered by four matched filters and filter outputs at the moments of spike occurrence are read by a computer and used for off-line separation and spike waveform reconstruction. Thirty-one double unit recordings were obtained and correlation between the separated spike trains was determined. After stimulus correction correlation remained in only 8 of the double unit records. It appeared that in most cases this neural correlation was stimulus dependent. Continuous noise stimulation resulted in the strongest neural correlation remaining after correction for stimulus coupling, stimulation with 48 ms duration tonepips presented once per second generally did not result in a significant neural correlation after the correction procedure for stimulus lock. The usefulness of the additive model for neural correlation and the correction procedure based thereupon is discussed.     

Differences in specificity and catalytic efficiency between allozymes of esterase-4 from Drosophila mojavensis

A more than 10-fold difference in the specificity and catalytic efficiency for 1-naphthyl esters was measured between two allozymes of esterase-4 from Drosophila mojavensis. This difference is mainly caused by a difference in the affinity for the 1-naphthyl esters. The amino acid compositions of the allozymes are not significantly different, which means that the difference in primary structure is small. Small differences in primary structure generally do not result in such a large increase in catalytic efficiency and such a large shift in substrate specificity as was found in the present study.