Anaemia in chronic respiratory failure.

BACKGROUND: In patients with severe chronic obstructive pulmonary disease (COPD), anaemia is common and associated with impaired long-term survival and quality of life. Whether anaemia is also prevalent in patients with other severe, non-inflammatory respiratory diseases has not yet been systematically tested. METHODS: In 595 patients with obstructive (OD, 54.8%) or restrictive disease (RD, 45.2%) and chronic respiratory failure (CRF), anthropometric data, laboratory parameters, lung function, blood gases and comorbidities were assessed prior to initiation of home mechanical ventilation. Patients were classified as anaemic based on haemoglobin (Hb) levels (Hb<12/13 g/dl, female patients/male patients). Patients with known causes for anaemia were excluded. RESULTS: In patients with CRF the prevalence of anaemia was 13.3% and not different between RD (11.5%) and OD (14.7%) (p=0.276). A sex-related difference occurred only in OD [7.9% (f) vs. 17.3% (m); p=0.035]. Patients with OD and anaemia presented with higher age (p=0.003), pH (p=0.014) and arterial oxygen pressure (PaO(2) ) (p=0.012), lower body mass index (BMI) (p=0.011) and total protein (p=0.012) and higher rates of coronary heart disease (p=0.01), cardiac arrhythmia (p=0.014) and diabetes mellitus (p=0.003) in comparison to non-anaemic patients. In patients with RD anaemia was associated with higher age, (p=0.008), pH (p=0.011) and lower leucocytes numbers (p=0.006). CONCLUSIONS: Anaemia is frequent not only in COPD but also in other severe respiratory diseases combined with CRF. It was associated with advanced age, several comorbidities, impaired nutritional state and elevations of pH and PaO(2) , probably because of hyperventilation. Its prognostic impact has to be elucidated in future studies.

Squalene-hopene cyclase from Methylococcus capsulatus (Bath): a bacterium producing hopanoids and steroids.

We report the cloning and characterisation of the Methylococcus capsulatus shc gene, which encodes the squalene-hopene cyclase (SHC). This enzyme catalyses the complex cyclization of squalene to the pentacyclic triterpene skeleton of hopanoids and represents the key reaction in this biosynthesis. Using a combination of PCR amplification and DNA hybridization, two overlapping 2.6 kb PstI and 3.3 kb SalI DNA fragments were cloned bearing a 1962 bp open reading frame encoding a 74 kDa protein with 654 amino acids and a predicted isoelectric point at about pH 6.3. The deduced amino acid sequence of the M. capsulatus shc gene showed significant similarity to known prokaryotic SHCs and to a lesser degree to the related eukaryotic oxidosqualene cyclases (OSCs). Like other triterpene cyclases, the M. capsulatus SHC contains seven so-called QW-motifs as well as an aspartate-rich domain. The recombinant M. capsulatus SHC was expressed in Escherichia coli and in vitro activity of the recombinant cyclase was demonstrated using crude cell-free lysate or solubilized membrane preparation. The cyclization products hop-22-ene and hopan-22-ol (diplopterol) were identified by GC and GC-MS.