pigk Mutation underlies macho behavior and affects Rohon-Beard cell excitability.

The study of touch-evoked behavior allows investigation of both the cells and circuits that generate a response to tactile stimulation. We investigate a touch-insensitive zebrafish mutant, macho (maco), previously shown to have reduced sodium current amplitude and lack of action potential firing in sensory neurons. In the genomes of mutant but not wild-type embryos, we identify a mutation in the pigk gene. The encoded protein, PigK, functions in attachment of glycophosphatidylinositol anchors to precursor proteins. In wild-type embryos, pigk mRNA is present at times when mutant embryos display behavioral phenotypes. Consistent with the predicted loss of function induced by the mutation, knock-down of PigK phenocopies maco touch insensitivity and leads to reduced sodium current (INa) amplitudes in sensory neurons. We further test whether the genetic defect in pigk underlies the maco phenotype by overexpressing wild-type pigk in mutant embryos. We find that ubiquitous expression of wild-type pigk rescues the touch response in maco mutants. In addition, for maco mutants, expression of wild-type pigk restricted to sensory neurons rescues sodium current amplitudes and action potential firing in sensory neurons. However, expression of wild-type pigk limited to sensory cells of mutant embryos does not allow rescue of the behavioral touch response. Our results demonstrate an essential role for pigk in generation of the touch response beyond that required for maintenance of proper INa density and action potential firing in sensory neurons.

Analysis of the Zebrafish perplexed mutation reveals tissue-specific roles for de novo pyrimidine synthesis during development.

The zebrafish perplexed mutation disrupts cell proliferation and differentiation during retinal development. In addition, growth and morphogenesis of the tectum, jaw, and pectoral fins are also affected. Positional cloning was used to identify a mutation in the carbamoyl-phosphate synthetase2-aspartate transcarbamylase-dihydroorotase (cad) gene as possibly causative of the perplexed mutation and this was confirmed by gene knockdown and pyrimidine rescue experiments. CAD is required for de novo biosynthesis of pyrimidines that are required for DNA, RNA, and UDP-dependent protein glycosylation. Developmental studies of several vertebrate species showed high levels of cad expression in tissues where mutant phenotypes were observed. Confocal time-lapse analysis of perplexed retinal cells in vivo showed a near doubling of the cell cycle period length. We also compared the perplexed mutation with mutations that affect either DNA synthesis or UDP-dependent protein glycosylation. Cumulatively, our results suggest an essential role for CAD in facilitating proliferation and differentiation events in a tissue-specific manner during vertebrate development. Both de novo DNA synthesis and UDP-dependent protein glycosylation are important for the perplexed phenotypes.

Distinct leucocyte redistribution after glucocorticoid treatment among difficult-to-treat asthmatic patients.

Difficult-to-treat asthma (DTA) represents a heterogeneous subgroup of asthma. Up to now, the lack of specific diagnosis not only complicates appropriate specification and control of asthma, but also makes targeted research difficult. The aim of this study is to categorize this heterogeneous group of DTA patients (n=27; referring to the GINA guidelines) based on the distinct leucocyte redistribution (LR) after glucocorticoid (GC) treatment. Furthermore, the effect of adjuvant therapies was investigated for its impact on LR. The frequency of CD3+, CD4+, CD8+, CD14+, CD19+ and NK cells was analysed in peripheral blood before and 3 h after systemic GC treatment, along with the markers of activation HLA-DR and CD25. Within 3 h of GC administration, a significant average decrease of 16% in CD3+CD4+ (P < or = 0.001) and a 12% increase in NK-cell frequency (P < or = 0.001) clearly distinguished two groups of patients: LR-responsive and LR-unresponsive patients. The CD3+CD8+ T-cell number and activation marker remained unchanged. Patients who received adjuvant therapy, such as methotrexate or interferon-alpha, because of poor clinical response to GC showed an LR similar to that showed by responsive patients. DTA patients comprise at least two immunologically distinct groups: patients showing an immediate decrease in CD3+CD4+ T cells and an increase in NK cells following GC administration and patients lacking an immediate change. Analysis of LR not only may allow the identification of immunologic steroid resistance, but also may be of value for immunologic determination of effective steroid doses.

[Allergic bronchopulmonary aspergillosis (ABPA)]. / Die allergische bronchopulmonale Aspergillose (ABPA).

Allergic bronchopulmonary aspergillosis (ABPA) is the most common allergic bronchopulmonary mycosis in humans. The diagnosis of the complex disease is based on defined criteria. Five clinical stages of ABPA were proposed. The extent of the defined criteria varies in the different stages, thus making diagnosis difficult. Particularly the discrimination of ABPA in remission stage (stage II) and allergic asthma with A. fumigatus-sensitisation may be an important problem. Early diagnosis in stages without persistent changes of bronchial wall and lung parenchyma is needed to prevent severe end stages of ABPA. The up to now widely used commercial (crude) allergen extracts for in vitro and in vivo diagnosis show batch to batch variation, insufficient standardization and lack of reproducibility. Potentials and limitations of routine diagnostic procedures in ABPA are described. The production of a panel of recombinant allergens of A. fumigatus and their evaluation for in vivo and particularly in vitro use has brought an important step forward in the early and precise diagnosis of ABPA. A panel of recombinant allergens is now available for routine assay in CAP-System. Glucocorticosteroids play a central role in therapy of ABPA. The approach in exacerbation phase and the long term therapy are described and also the indication for antimycotic drugs.

[Allergic bronchopulmonary aspergillosis (ABPA)]. / Die allergische bronchopulmonale Aspergillose (ABPA).

ABPA is the most common allergic bronchopulmonary mycosis in humans. The diagnosis of the complex disease is based on defined criteria. Five clinical stages of ABPA were proposed. The extend of the defined criteria varies in the different stages, thus making diagnosis difficult. Particularly the discrimination of ABPA in remission stage (stage II) and allergic asthma with A--sensitisation may be an important problem. Early diagnosis in stages without persistent changes of bronchial wall and lung parenchyma is needed to prevent severe end stages of ABPA. The up to now widely used commercial (crude) allergen extracts for in vitro and in vivo diagnosis show batch to batch variation, insufficient standardization and lack of reproducibility. Potentials and limitations of routine diagnostic procedures in ABPA are described. The production of a panel of recombinant allergens of A. fumigatus and their evaluation for in vivo and particularly in vitro use has brought an important step forward in the early and precise diagnosis of ABPA. A panel of recombinant allergens is now available for routine assay in CAP-System.