Ara h 8, a Bet v 1-homologous allergen from peanut, is a major allergen in patients with combined birch pollen and peanut allergy

BACKGROUND: We recently described patients with soybean allergy mainly mediated by cross-reactivity to birch pollen allergens. A majority of those patients were reported to have peanut allergy. OBJECTIVE: We sought to study the occurrence of peanut allergy in patients allergic to birch pollen and characterized the Bet v 1-homologous peanut allergen Ara h 8. METHODS: Recombinant Ara h 8 was cloned with degenerated primers and expressed in Escherichia coli. Nine Swiss and 11 Dutch patients with peanut and birch pollen allergy and a positive double-blind, placebo-controlled food challenge result to peanut were investigated for IgE reactivity to birch pollen and purified peanut allergens and cross-reactivity between birch and peanut. Ara h 8 stability against digestion and roasting was assessed by means of RAST inhibition. The IgE cross-linking potency of Ara h 8 was tested on the basis of basophil histamine release. RESULTS: During double-blind, placebo-controlled food challenge, all patients experienced symptoms in the oral cavity, progressing to more severe symptoms in 40% of patients. CAP-FEIA detected recombinant (r) Ara h 8-specific IgE in 85%. IgE binding to Ara h 8 was inhibited by Bet v 1 in peanut extract immunoblotting and in RAST inhibition. In EAST inhibition recombinant rAra h 8 inhibited IgE binding to peanut in 4 of 7 tested patient sera. Antipeanut response was dominated by Ara h 8 in 12 of 17 tested patients. Furthermore, our results demonstrate a low stability of Ara h 8 to roasting and no stability to gastric digestion. Basophil histamine release with rAra h 8 was more than 20% in 5 of 7 tested sera. CONCLUSIONS: Peanut allergy might be mediated in a subgroup of our patients by means of cross-reaction of Bet v 1 with the homologous peanut allergen Ara h 8.     

Functional overexpression of wild-type p53 correlates with alveolar cell differentiation in the developing human lung

At 15 weeks after conception (a.c.), the human pulmonary acinus is lined by distal low-columnar and more proximal cuboidal cells that are successive stages in alveolar type II cell differentiation (pseudoglandular period of lung development). From 16 weeks a.c. onward, there are also 'flatter' cells that are intermediate stages in the differentiation of cuboidal type II cells into squamous type I cells (canalicular period). We investigated the role of wild-type p53 protein and the proliferation marker Ki-67 in the differentiation of type II and type I cells in these two periods. Serial sections from fetal lungs (n = 30) were immunoincubated with antibodies against p53 and Ki-67. The presence of prospective type II and type I cells was confirmed using immunohistochemistry for surfactant protein SP-A as a differentiation marker and light and electron microscopy. The p53 and Ki-67 positive nuclei were quantified per alveolar cell phenotype (i.e., low-columnar; cuboidal; flatter). The occurrence of cell apoptosis was studied using propidium iodide (PI) and 4',6'-diamino-2-phenylindol dihydrochloride (DAPI) staining. The combined increase in p53 expression and decrease in Ki-67 expression during alveolar epithelial cell differentiation suggests that wild-type p53 protein plays a role in the differentiation of alveolar type II and type I cells in the human lung, and that this function is mediated through cell cycle arrest. The rare incidence of apoptotic nuclei in alveolar type II cells, together with their absence in alveolar type I cells, supports the view that p53 is involved in the differentiation, rather than the death, of alveolar epithelial cells.     

SOST expression is restricted to the great arteries during embryonic and neonatal cardiovascular development.

Spatial-temporal regulation of bone morphogenetic protein (BMP) and Wnt activity is essential for normal cardiovascular development, and altered activity of these growth factors causes maldevelopment of the cardiac outflow tract and great arteries. In the present study, we show that SOST, a Dan family member reported to antagonize BMP and Wnt activity, is expressed within the medial vessel wall of the great arteries containing smooth muscle cells. The ascending aorta, aortic arch, brachiocephalic artery, common carotids, and pulmonary trunk were all associated with SOST expressing smooth muscle cells, while the heart itself, including the valves, and more distal arteries, that is, pulmonary arteries, subclavian arteries, and descending aorta, were negative. SOST was expressed from embryonic day 15.5 up to the neonatal period. SOST expression, however, did not correspond with inhibition of Smad-dependent BMP activity or beta-catenin-dependent Wnt activity in the great arteries. Activity of both signaling pathways was already down-regulated before induction of SOST expression.     

Dithiothreitol prevents age-associated decrease in oocyte/conceptus viability in vitro

The present study was designed to ascertain whether the negative effects on reproductive potential of post-ovulatory ageing in vitro of oocytes can be prevented by antioxidant therapy. Mouse metaphase II (MII) oocytes were aged in vitro for 12 h prior to insemination in the presence of varying concentrations of L-ascorbic acid, 6-methoxy- 2,5,7,8-tetramethylchromane-2-carboxylic acid (Trolox), L-cystine dihydrochloride, ethylenediaminetetraacetic acid (EDTA), beta- mercaptoethanol and DL-dithiothreitol (DTT). In-vitro ageing of oocytes was associated with lower fertilization rate, higher proportion of concepti exhibiting cellular fragmentation at 24 h post-insemination and lower percentage of concepti reaching the blastocyst stage. Ascorbic acid, Trolox and EDTA had no effect on cellular fragmentation or potential of oocytes for development. However, the probability of an oocyte reaching the blastocyst stage was decreased (P < or = or = 0.05) in oocytes incubated in the presence of L-cystine (50 and 500 microM) and beta-mercaptoethanol (5, 50 and 500 microM) when compared to control aged oocytes. Age-associated cellular fragmentation at 24 h post-insemination was partially prevented (P < or = 0.05) by incubating oocytes in the presence of beta-mercaptoethanol (500 microM). DTT (50 and 500 microM) increased (P < or = 0.05) fertilization rate and number of cells at 81 h post-insemination to levels similar to those exhibited by control oocytes. Furthermore, both age-associated fragmentation at 24 h post-insemination (P < or = 0.05) and decreased potential of oocytes for development to the blastocyst stage (P < or = 0.05) were prevented, at least in part, by culturing oocytes in the presence of DTT (50 microM). Although the mechanism by which DTT exerts its beneficial effects on aged oocytes remains to be elucidated, it may protect oocytes by preventing oxidation of free thiol groups and/or altering a redox-independent signalling pathway that mediates cellular fragmentation and death.      

Absence of caspase 3 activation in neoplastic cells of nasopharyngeal carcinoma biopsies predicts rapid fatal outcome.

Poor prognosis in nasopharyngeal carcinoma patients may result from resistance to the apoptosis-inducing effect of radio- and/or chemotherapy. Apoptosis depends on proper activation of caspase 3, resulting in cleavage of key proteins like PARP-1. To investigate whether disruption of the apoptosis pathway results in therapy-resistant tumour cells, we investigated whether absence of caspase 3 activation in tumour biopsies of nasopharyngeal carcinoma patients is related to poor clinical outcome. Moreover, we investigated whether absence of caspase 3 activation is related to loss of procaspase 3 expression or expression of the apoptosis regulators p53, bcl-2 and XIAP. We studied 36 Indonesian nasopharyngeal carcinoma patients without evidence of distant metastases who were treated with curative intent by radiotherapy only. Activation of caspase 3 and expression of the different markers were determined using specific antibodies. Levels of caspase 3 activation were determined by quantifying positively staining tumour cells. Nasopharyngeal carcinoma-derived C15 and C17 tumour cells were used as control. Absence of caspase 3 activation was strongly related to a poor clinical response to radiotherapy and to a higher T and N stage, resulting in a particularly poor clinical outcome with regard to progression-free (P<0.0001) and overall survival time (P<0.0001). Absence of caspase 3 activation was significantly correlated to loss of expression of procaspase 3 (P=0.04). In nasopharyngeal carcinoma patients treated with curative intent, absence of active caspase 3-positive neoplastic cells predicts rapid fatal outcome, and is associated with poor response to radiotherapy and high T and N stage at time of presentation.     

Aspects of average response computation by aperiodic stimulation

A mathematical analysis of the variance of the average evoked-response computation as a function of the numberN of stimuli presented is made for the case when the response is disturbed by additive stationary noise. A comparison is made between the variance for purely periodic stimuli and that for stimuli of which the interstimulus durations are Gaussian distributed. In the latter situation, the interval durations may be correlated with each other, e.g. according to a Gaussian Markov process. It is deduced that, in general, the introduction of aperiodic stimulation tends to make the functional relationship between the variance andN behave as though it holds for noise with a very broad frequency spectrum; the variance is proportional to 1/N.     

Disruption of the Aspergillus niger argB gene: a tool for transformation

We disrupted the Aspergillus niger gene argB, encoding ornithine transcarbamylase. Full characterisation of the argB deletion was performed by Southern blot analysis, growth tests and by means of mitotic recombination, complementation and transformation. The argB locus was found to be physically removed, thus creating an auxotrophic mutation. The latter can be supplemented by addition of arginine into the culture medium. The argB gene and its disruption do not correlate to the argI13 (formerly argB13) allele described. The delta argB is on chromosome I whereas argI13 is on V. In addition, the argI13 mutation can only be complemented by the A. nidulans argB gene, whereas the new argB deletion can be complemented by both the A. niger and A. nidulans argB genes. The delta argB strain has been used to generate several strains in a breeding programme and to study the expression of important genes, such as areA and kexB.     

The impact of reinforcement contingencies on AD/HD: a review and theoretical appraisal

One of the core deficits in attention deficit/hyperactivity disorder (AD/HD) is thought to be an aberrant sensitivity to reinforcement, such as reward and response cost. Twenty-two studies (N=1181 children) employing AD/HD and reinforcement contingencies are reviewed from vantage points: task performance, motivation, and psychophysiology. Results indicate that reinforcement contingencies have a positive impact on task performance and levels of motivation for both children with AD/HD and normal controls. There is evidence that the effect related to task performance is somewhat more prominent in AD/HD. There is some evidence that a high intensity of reinforcement is highly effective in AD/HD. Children with AD/HD prefer immediate over delayed reward. From a psychophysiological point of view, children with AD/HD seem less sensitive to reinforcement compared to controls. While comorbid disorders are suggested to be confounders of the dependent variables, many studies do not examine the effect of oppositional defiant disorder (ODD) and conduct disorder (CD). We discuss the implications of the findings for five theoretical frameworks, including the model by, the cognitive-energetic model (CEM), the dual-pathway model and the BIS/BAS model. Results show a discrepancy between the theoretical models and the behavioural findings.     

The oxidizing agent tertiary butyl hydroperoxide induces disturbances in spindle organization, c-meiosis, and aneuploidy in mouse oocytes

It has been recently proposed that a concomitant generationof oxidative stress of oocytes with increasing maternal agemay be a major factor responsible for the age-related increasein aneuploid conceptions. As a preliminary step in the testingof this hypothesis, we need to confirm that oxidative stressin itself can induce errors in chromosome segregation. In orderto achieve this goal, germinal vesicle (GV)-stage mouse oocytesfrom unstimulated ICR and (C57BLxCBA) F₁ hybrid female micewere matured in vitro for 9 h for metaphase I (MI) oocytes or16 h for metaphase II (MII) oocytes in the presence of varyingconcentrations of the oxidizing agent tertiary-butyl hydroperoxide(tBH). MII oocytes from (C57BLxCBA) F₁ hybrid mice were fixedand C-banded for karyotyping analysis. MI and MII oocytes fromICR mice were fixed and stained with the DNAfluorescent probe4',6-diamidino-2-phenylindole (DAPI) to detect abnormalitiesin chromosomal distribution. Meiosis I and meiosis II spindlesfrom ICR mice were visualized by confocal immunofluorescencemicroscopy. Data from these experiments demonstrate that in-vitroexposure of mouse oocytes to tBH during meiosis I reduces thelength (pole-to-pole distance) and width (diameter at the equatorof the spindle) of meiosis I and meiosis II spindles. This reductionis associated with an increase in the percentage of oocytesshowing chromosome scattering and clumping on the MII plate,and of aneuploidy (hyperhaploidy) in MII oocytes. However, tBHat the concentrations used in the present study has only a minimalnegative effect on the frequency of meiotic maturation. Theseresults suggest that oxidative stress during meiotic maturationin vitro may induce chromosomal errors that are undetectablein the living oocyte and whose developmental consequences maybecome manifest after fertilization. aneuploidy/meiosis/mouse oxidative stress/spindle/tertiary butyl hydroperoxide