Time Space Translation: A Hox Mechanism for Vertebrate A-P Patterning

The vertebrate A-P axis is a time axis. The head is made first and more and more posterior levels are made at later and later stages. This is different to the situation in most other animals, for example, in Drosophila. Central to this timing is Hox temporal collinearity (see below). This occurs rarely in the animal kingdom but is characteristic of vertebrates and is used to generate the primary axial Hox pattern using time space translation and to integrate successive derived patterns (see below). This is thus a different situation than in Drosophila, where the primary pattern guiding Hox spatial collinearity is generated externally, by the gap and segmentation genes.     

Early postnatal lethality and cardiovascular defects in CXCR7-deficient mice

CXCR7 is a G-protein coupled receptor that was recently deorphanized and shown to have SDF1 and I-TAC as high affinity ligands. Here we describe the characterization of CXCR7-deficient mice that were generated to further investigate the function of this receptor in vivo. Expression analysis using a LacZ reporter knockin revealed that postnatally Cxcr7 was specifically expressed in cardiomyocytes, vascular endothelial cells of the lung and heart, the cerebral cortex and in osteocytes of the bone. Adult tissues revealed high expression in cardiomyocytes and osteocytes. The observation that 70% of the Cxcr7-/- mice died in the first week after birth coincides with expression of Cxcr7 in vascular endothelial cells and in cardiomyocytes. An important role of CXCR7 in the cardiovascular system was further supported by the observation that hearts of the Cxcr7-/- mice were enlarged, showed myocardial degeneration and fibrosis of postnatal origin, and hyperplasia of embryonic origin. Despite high expression in osteocytes no apparent bone phenotype was observed, neither in combination with ovariectomy nor orchidectomy. Thus as CXCR7 does not seem to play an important role in bone our data indicate an important function of CXCR7 in the cardiovascular system during multiple steps of development.     

Cubicle Refusal in Norwegian Dairy Herds

In order to survey the behaviour of choosing the alley area instead of a cubicle as a lying place (cubicle refusal), a questionnaire was sent to the 273 dairy farms in Norway known to keep cows in cubicle housing systems. Sixty-six percent of the farmers contacted were included in the study. The median herd size was 18 cows (range 7–118). More than 85% of the herds had sheds providing one or more cubicles per cow. The mean herd occurrence of cubicle refusal was 6%, but showed great variation (range 0–55%). Regression analysis showed a significant association between rearing heifers in slatted floor pens and an increased cubicle refusal occurrence (p = 0.02, R² = 0.05), while herd size, use of litter, or cubicle-to-animal ratio were not found to be associated with cubicle refusal. The practice of rearing heifers in slatted floor pens accounted for about one half of the observed cubicle refusal (etiologic fraction = 0.51).     

Autoantibody systems in rheumatoid arthritis: specificity, sensitivity and diagnostic value

The diagnosis of rheumatoid arthritis (RA) is primarily based on clinical symptoms, so it is often difficult to diagnose RA in very early stages of the disease. A disease-specific autoantibody that could be used as a serological marker would therefore be very useful. Most autoimmune diseases are characterized by a polyclonal B-cell response targeting multiple autoantigens. These immune responses are often not specific for a single disease. In this review, the most important autoantibody/autoantigen systems associated with RA are described and their utility as a diagnostic and prognostic tool, including their specificity, sensitivity and practical application, is discussed. We conclude that, at present, the antibody response directed to citrullinated antigens has the most valuable diagnostic and prognostic potential for RA.     

Experimentally Induced Stress Validated by EMG Activity

Experience of stress may lead to increased electromyography (EMG) activity in specific muscles compared to a non-stressful situation. The main aim of this study was to develop and validate a stress-EMG paradigm in which a single uncontrollable and unpredictable nociceptive stimulus was presented. EMG activity of the trapezius muscles was the response of interest. In addition to linear time effects, non-linear EMG time courses were also examined. Taking into account the hierarchical structure of the dataset, a multilevel random regression model was applied. The stress paradigm, executed in N = 70 subjects, consisted of a 3-minute baseline measurement, a 3-minute pre-stimulus stress period and a 2-minute post-stimulus phase. Subjects were unaware of the precise moment of stimulus delivery and its intensity level. EMG activity during the entire experiment was conform a priori expectations: the pre-stimulus phase showed a significantly higher mean EMG activity level compared to the other two phases, and an immediate EMG response to the stimulus was demonstrated. In addition, the analyses revealed significant non-linear EMG time courses in all three phases. Linear and quadratic EMG time courses were significantly modified by subjective anticipatory stress level, measured just before the start of the stress task. Linking subjective anticipatory stress to EMG stress reactivity revealed that subjects with a high anticipatory stress level responded with more EMG activity during the pre-stimulus stress phase, whereas subjects with a low stress level showed an inverse effect. Results suggest that the stress paradigm presented here is a valid test to quantify individual differences in stress susceptibility. Further studies with this paradigm are required to demonstrate its potential use in mechanistic clinical studies.     

Bestimmung von deoxynivalenol mittels LC - MS/MS (Tandem Massenspektrometrie)

A sensitive and selective method using high-performance liquid chromatography in combination with atmospheric pressure chemical ionization tandem mass spetrometry (LC-APCI-MS/MS) has been developed for the determination of Deoxynivalenol (DON) in trace levels. The extract was purified with a MultiSep? column followed by the Vicam? DON immunoaffinity column. Quantification is based on an external standard method using positive Multiple Reaction Monitoring (MRM). The limit of detection was 5 μg/kg with a signal to noise ratio of 3:1.     

Functional changes in human leukemic cell line HL-60. A model for myeloid differentiation

Polar solvents induce terminal differentiation in the human promyelocytic leukemia cell line HL-60. The present studies describe the functional changes that accompany the morphologic progression from promyelocytes to bands and poly-morphonuclear leukocytes (PMN) over 9 d of culture in 1.3 percent dimethylsulfoxide (DMSO). As the HL-60 cells mature, the rate of O(2-) production increase 18-fold, with a progressive shortening of the lag time required for activation. Hexosemonophosphate shunt activity rises concomitantly. Ingestin of paraffin oil droplets opsonized with complement or Ig increases 10-fold over 9 d in DMSO. Latex ingestion per cell by each morphologic type does not change significantly, but total latex ingestion by groups of cells increases with the rise in the proportion of mature cells with greater ingestion capacities. Degranulation, as measured by release of β-glucuronidase, lysozyme, and peroxidase, reaches maximum after 3-6 d in DMSO, then declines. HL-60 cells contain no detectable lactoferrin, suggesting that their secondary granules are absent or defective. However, they kill staphylococci by day 6 in DMSO. Morphologically immature cells (days 1-3 in DMSO) are capable of O(2-) generation, hexosemonophosphate shunt activity, ingestion, degranulation, and bacterial killing. Maximal performance of each function by cells incubated in DMSO for longer periods of time is 50-100 percent that of normal PMN. DMSO- induced differentiation of HL-60 cells is a promising model for myeloid development.     

Computing approximate standard errors for genetic parameters derived from random regression models fitted by average information REML

Approximate standard errors (ASE) of variance components for random regression coefficients are calculated from the average information matrix obtained in a residual maximum likelihood procedure. Linear combinations of those coefficients define variance components for the additive genetic variance at given points of the trajectory. Therefore, ASE of these components and heritabilities derived from them can be calculated. In our example, the ASE were larger near the ends of the trajectory.     

The adsorption of prothrombin to phospholipid monolayers quantitated by ellipsometry

We investigated by means of an automated ellipsometer the calcium-dependent binding of prothrombin from a buffer solution to monolayers of dioleoylphosphatidylserine (DOPS) and dioleoylphosphatidylcholine (DOPC) deposited on chromium slides. This technique allows direct measurements of bound and free protein concentrations and is not hampered by calcium-induced aggregation of vesicles. For pure DOPS a dominant class of binding sites exists with a dissociation constant, Kd = (6 +/- 2) X 10(-10) M (mean +/- S.D.) and maximal binding of prothrombin, gamma max = 0.26 +/- 0.03 micrograms/cm2. Incorporation of a small fraction of DOPC in the monolayer causes a large decrease in the binding affinity with a pronounced biphasic behavior of the binding curve. For monolayers consisting of 20% DOPS and 80% DOPC the binding curve becomes monophasic with Kd = (1.6 +/- 0.6) X 10(-7) M and gamma max = 0.22 +/- 0.03 micrograms/cm2. The procoagulant activity of the monolayers was tested by measuring the generation of thrombin after addition of prothrombin and activated coagulation factors X and V. The thrombin-generating capacity of monolayers and single-bilayer vesicles is comparable but is apparently diffusion limited in the monolayer system. The calcium-dependent formation of stacked multilayers according to the Blodgett technique appeared to be strongly influenced by the DOPS/DOPC ratio in the phospholipid monolayer. From these results it is concluded that for pure DOPS monolayers high-affinity prothrombin-phospholipid and phospholipid-phospholipid interactions exist which are radically disturbed when the monolayer contains more than 20-30% of DOPC.