Safety of research bronchoscopy, biopsy and bronchoalveolar lavage in asthma

Bronchoscopy with endobronchial biopsy (EBB) and/or bronchoalveolar lavage (BAL) has become an important research tool in asthma. A recent report has suggested audit and reporting of the safety of these procedures. A total of 159 asthmatic patients (84 males, 75 females), aged 18-52 (median 27) yrs, forced expiratory volume in one second 53-120 (median 88) % predicted, underwent 273 bronchoscopies in six clinical research studies. On 228 occasions, EBB and BAL were performed and, on 45 occasions, EBB was performed alone. On 48 occasions, bronchoscopy was performed 24 h post-allergen challenge. Adverse events occurred on 34 out of 273 occasions, none of which were following allergen challenge. Post-EBB and BAL, four patients developed pleuritic chest pain, shortness of breath and fever. A further two patients experienced pleuritic chest pain alone post-EBB/BAL. Bronchospasm or worsening of asthma symptoms occurred on 14 occasions, 13 post-EBB/BAL and on one occasion post-EBB alone. Fever/flu-like symptoms were reported on nine occasions following EBB and BAL. One subject had haemoptysis post-EBB/BAL, but required no intervention. In conclusion, bronchoscopy, endobronchial biopsy and bronchoalveolar lavage can be performed safely in asthmatic patients. Most of the complications were seen where bronchoalveolar lavage and endobronchial biopsy were both performed, suggesting that bronchoalveolar lavage accounts for most of the adverse events.

Drosophila double parked: a conserved, essential replication protein that colocalizes with the origin recognition complex and links DNA replication with mitosis and the down-regulation of S phase transcripts

We identified a Drosophila gene, double parked (dup), that is essential for DNA replication and belongs to a new family of replication proteins conserved from Schizosaccharomyces pombe to humans. Strong mutations in dup cause embryonic lethality, preceded by a failure to undergo S phase during the postblastoderm divisions. dup is required also for DNA replication in the adult ovary, establishing that dup is needed for DNA replication at multiple stages of development. Strikingly, DUP protein colocalizes with the origin recognition complex to specific sites in the ovarian follicle cells. This suggests that DUP plays a direct role in DNA replication. The dup transcript is cell cycle regulated and is under the control of E2F and Cyclin E. Interestingly, dup mutant embryos fail both to downregulate S phase genes and to engage a checkpoint preventing mitosis until completion of S phase. This could be either because these events depend on progression of S phase beyond the point blocked in the dup mutants or because DUP is needed directly for these feedback mechanisms.

The putative Drosophila methyltransferase gene dDnmt2 is contained in a transposon-like element and is expressed specifically in ovaries

Several organisms, including Drosophila melanogaster, are apparently devoid of DNA methylation. This might reflect a highly restricted activity of DNA methyltransferases, a loss of methyltransferase activity during evolution or the dispensability of DNA methylation due to an efficient substitute mechanism. Vestiges of a Drosophila DNA methylation system have been identified recently. We show here that the putative DNA methyltransferase gene, dDnmt2, is the component of a transposon-like element. This element also contains a second, novel open reading frame with homologies to a yeast protein involved in RNA processing. Both open reading frames are coordinately expressed and transcripts are present specifically in ovarian nurse cells as well as during early stages of embryonic development.

Inhaled steroid therapy in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) remains difficult to manage. Patients with COPD present with progressive dyspnea; difficulty in stopping smoking; recurrent exacerbations; and, ultimately, respiratory failure. Because of the lack of proven treatments for COPD and because inhaled corticosteroids can prevent airway inflammation and permanent lung damage in patients with asthma, it has become common practice to prescribe inhaled corticosteroids for patients with COPD despite a lack of data suggesting that these agents have any long-term benefit in these patients. In the past 12 months, three randomized, double-blind, placebo-controlled clinical trials (the European Respiratory Society Study on Chronic Obstructive Pulmonary Disease, the Copenhagen City Lung Study, and the Inhaled Steroids in Obstructive Lung Disease study) designed to assess the long-term effect of inhaled corticosteroids in patients with varying severity of airway obstruction have been presented. The results of these studies have been disappointing; they show little to suggest that any long-term benefit is gained from using inhaled corticosteroids in most patients with COPD, whether they continue to smoke or not.

Mutations in Drosophila DP and E2F distinguish G1-S progression from an associated transcriptional program

The E2F transcription factor, a heterodimer of E2F and DP subunits, is capable of driving the G1-S transition of the cell cycle. However, mice in which the E2F-1 gene had been disrupted developed tumors, suggesting a negative role for E2F in controlling cell proliferation in some tissues. The consequences of disrupting the DP genes have not been reported. We screened for mutations that disrupt G1-S transcription late in Drosophila embryogenesis and identified five mutations in the dDP gene. Although mutations in dDP or dE2F nearly eliminate E2F-dependent G1-S transcription, S-phase still occurs. Cyclin E has been shown to be essential for S-phase in late embryogenesis, but in dDP and dE2F mutants the peaks of G1-S transcription of cyclin E are missing. Thus, greatly reduced levels of cyclin E transcript suffice for DNA replication until late in development. Both dDP and dE2F are necessary for viability, and mutations in the genes cause lethality at the late larval/pupal stage. The mutant phenotypes reveal that both genes promote progression of the cell cycle.

Identification and analysis of multigene families by comparison of exon fingerprints

Gene families are often recognised by sequence homology using similarity searching to find relationships, however, genomic sequence data provides gene architectural information not used by conventional search methods. In particular, intron positions and phases are expected to be relatively conserved features, because mis-splicing and reading frame shifts should be selected against. A fast search technique capable of detecting possible weak sequence homologies apparent at the intron/exon level of gene organization is presented for comparing spliceosomal genes and gene fragments. FINEX compares strings of exons delimited by intron/exon boundary positions and intron phases (exon fingerprint) using a global dynamic programming algorithm with a combined intron phase identity and exon size dissimilarity score. Exon fingerprints are typically two orders of magnitude smaller than their nucleic acid sequence counterparts giving rise to fast search times: a ranked search against a library of 6755 fingerprints for a typical three exon fingerprint completes in under 30 seconds on an ordinary workstation, while a worst case largest fingerprint of 52 exons completes in just over one minute. The short "sequence" length of exon fingerprints in comparisons is compensated for by the large exon alphabet compounded of intron phase types and a wide range of exon sizes, the latter contributing the most information to alignments. FINEX performs better in some searches than conventional methods, finding matches with similar exon organization, but low sequence homology. A search using a human serum albumin finds all members of the multigene family in the FINEX database at the top of the search ranking, despite very low amino acid percentage identities between family members. The method should complement conventional sequence searching and alignment techniques, offering a means of identifying otherwise hard to detect homologies where genomic data are available.