Assignment of three human high-affinity Fcγ receptor I genes to chromosome 1, band q21.1

Correspondence to: J. G. J. van de Winkel.     

A method for the detection of abnormal leukocytes using cytochemical criteria

An alarm system for the detection of abnormal leukocytes using off-line data processing of the image of the peroxidase channel oscilloscope picture of the Hemalog-D is presented. The basic idea is that areas on the oscilloscope picture where more than a negligible number of nonpathological leukocytes may be depicted are delimited from the remaining area, which is divided into three alarm zones. The corresponding alarm quantities are the large unstained cells (LUC) or the unstained alarm (UA), the intermediate alarm (IA), and the stained alarm (SA). Reference intervals for these alarms were established using blood specimens from 15 healthy subjects. The system was tested using blood specimens from four patients with acute lymphoblastic leukemia (ALL) and 11 patients with acute myeloblastic leukemia (AML). The UA was the best alarm overall, but for seven of the AML specimens the IA or the SA alarm was superior. The high peroxidase (HPX) and the remainder alarms were inferior to the other alarms. Using the reference mean plus two standard deviations as a cutoff value, the smallest blast cell number fraction detectable by the best alarm was calculated to be smaller than 2% for each of the AML specimens, while it ranged from 7 to 2.9% for the ALL specimens.     

Autofluorescence-activated cell sorting of pancreatic islet cells: purification of insulin-containing B-cells according to glucose-induced changes in cellular redox state

Autofluorescence-activated cell sorting can be employed for the subfractionation of insulin-containing islet B-cells according to their responsiveness to their physiologic stimulus, glucose. The method utilizes a flow cytometric detection of the rapid variations in endogenous NAD (P) H - and FAD - fluorescence after exposure to 20 mM glucose. Under these conditions, a two-fold increase in NAD (P) H and a 40% decrease in FAD was observed in more than 75% of B-cells isolated from fed normal rats. The technique makes it possible to study the metabolic behaviour of the B-cell population in (physio)pathological conditions of impaired glucose-induced insulin release; the availability of functionally homogenous B-cell preparations facilitates studies on stimulus-secretion coupling. In view of the universal role of the cellular metabolic redox state in cell regulation, it is suggested that similar techniques can be developed for the metabolic analysis of other cell types and for their purification according to their responsiveness to specific stimuli.     

Towards minimized gonadotropins with full bioactivity.

Gonadotropins are highly complex glycoprotein hormones consisting of two noncovalently associated subunits, which are heavily glycosylated. Using the X-ray structure of human choriogonadotropin and structure/activity relationships we aimed to design 'minimized' gonadotropins of reduced complexity. Our results show that it is possible to reduce the size of natural human choriogonadotropin by one-third of its molecular weight while retaining its wild-type biopotency. To our knowledge, such 'mini'-human choriogonadotropins represent the smallest gonadotropins described so far with an lutropin/choriogonadotropin receptor affinity and in vitro biological activity comparable with that of natural human choriogonadotropin. It provides an important step towards the structure/function-based design of small molecule drugs to the human gonadotropin receptors.     

Comparison of office chairs with fixed forwards or backwards inclining, or tiltable seats

Three adjustments of an office chair seat: one inclining +10 degrees (forwards), one inclining -5 degrees (backwards), and one being freely tiltable from -8 degrees to +19.5 degrees were investigated using two groups of healthy female workers in a field (n = 12), and a laboratory study (n = 10), respectively. The seat adjustments were examined with regard to effects on foot swelling, lumbar muscular load, backrest pressure and subjective acceptability. Desk-work and typing were compared according to lumbar muscular activity, seat movements (tiltable seat), and backrest pressure. Foot swelling tended to increase with increasing seat height but was not influenced by the ability to tilt the seat or not. With the different seat adjustments lumbar muscular activity did not change systematically in spite of greater backrest pressure when the seat inclined backwards. The tiltable seat was preferred to the others. Typing was associated with a more constrained and tens posture than desk work, because movements, transferred to the tiltable seat, decreased and the muscular load increased. Backrest pressure was highest during typing. A tendency towards gradually increasing restlessness (i.e. seat movements) and increasing forward inclination of the tiltable seat with time was observed.     

Effect of the timing of water deficit on growth, phenology and yield of pearl millet (Pennisetum glaucum (L.) R. Br.) grown in Sahelian conditions

Several studies conducted under high input conditions have indicatedlittle susceptibility of pearl millet to water deficit untillearly grain filling, because the losses in main shoot productionwere fully compensated by increased tiller fertility. The presentstudy assessed the impact of water deficits at three developmentstages: prior to flowering (S30), at the beginning of flowering(S45), and at the end of flowering (S60) in pearl millet grownin experimental conditions similar to Sahelian farming conditions.It included a control irrigation treatment simulating the naturaldistribution of rainfall throughout the cropping season. Bothbiomass production and grain yield were severely reduced byS30 and S45, while S60 had no effect. In S30 and S45, the floweringof tillers was delayed or totally inhibited. In both of thesetreatments, the low number of productive tillers did not compensatefor damage to panicle initiation and flowering of the main shoot.All treatments maintained green leaves on the main shoot duringthe grain filling period, and in S30 leaf growth recovered frommid-season drought. These results illustrate how pearl milletmostly escapes drought by matching its phenology to the meanrainfall distribution in the Sahel. In the case of mid-seasondrought, some late productive tillers and the maintenance ofgreen leaf biomass of the main shoots limited, but did not overcome,the yield losses. This study stresses the importance of agro-ecologicalconditions in control treatments, particularly the water regimeand crop density, when assessing crop drought resistance. Key words: Drought resistance strategy, experimental conditions, main shoots, tillers, Pennisetum glaucum