Cyclic di-GMP (c-di-GMP) is the specific nucleotide regulator of β-1,4-glucan (cellulose) synthase in Acetobacter xylinum. The enzymes controlling turnover of c-di-GMP are diguanylate cyclase (DGC), which catalyzes its formation, and phosphodiesterase A (PDEA), which catalyzes its degradation. Following biochemical purification of DGC and PDEA, genes encoding isoforms of these enzymes have been isolated and found to be located on three distinct yet highly homologous operons for cyclic diguanylate, cdg1, cdg2, andcdg3. Within each cdg operon, apdeA gene lies upstream of a dgc gene.cdg1 contains two additional flanking genes,cdg1a and cdg1d. cdg1a encodes a putative transcriptional activator, similar to AadR of Rhodopseudomonas palustris and FixK proteins of rhizobia. The deduced DGC and PDEA proteins have an identical motif structure of two lengthy domains in their C-terminal regions. These domains are also present in numerous bacterial proteins of undefined function. The N termini of the DGC and PDEA deduced proteins contain putative oxygen-sensing domains, based on similarity to domains on bacterial NifL and FixL proteins, respectively. Genetic disruption analyses demonstrated a physiological hierarchy among the cdg operons, such that cdg1contributes 80% of cellular DGC and PDEA activities andcdg2 and cdg3 contribute 15 and 5%, respectively. Disruption of dgc genes markedly reduced in vivo cellulose production, demonstrating that c-di-GMP controls this process.
Indoor air pollution became a recent concern found to be oftentimes worse than outdoor air quality. We developed a tool that is cheap and simple and enables continuous monitoring of air toxicity. It is a biosensor with both a nondisposable (monitor) and disposable (calcium alginate pads with immobilized bacteria) elements. Various parameters to enhance its signal have been tested (including the effect of the pad's orientation, it's exposure to either temperature or time with the air toxicant analyte, and various concentrations thereof). Lastly, the sensor has demonstrated its ability to sense the presence of chemicals in a real, indoor environment. This is the first step in the creation of a sensitive and simple operative tool that may be used in different indoor environments.
Data are presented on the distribution of all newly diagnosed brain tumors in Israel between 1960 and 1964. The mean annual incidence among Jews was 4.4 per 100,000 for malignant tumors with a male/female ratio of 1.4:1, and 2.4 per 100,000 for benign tumors with a sex ratio of 0.6:1. The incidence among the Arabic segment of the population was considerably lower, probably due to underdiagnosis. Malignant tumors were significantly higher among European and Israeli born residents compared with both the Asian and African born. Similar differences were noted with regard to benign tumors but these were only of borderline significance. Glioblastoma multiforme constituted 40% of all malignant tumors, increasing from 11% in childhood to 58% in older patients. Medulloblastoma and astrocytoma were the dominant tumors in childhood. Meningioma constituted 72% of all benign tumors and close to 24% of all tumors combined.
BACKGROUND Introduction of the GlideScope videolaryngoscope caused a change in use of other devices for difficult airway management. OBJECTIVE The influence of the GlideScope videolaryngoscope on changes in the indications for and the frequency of use of flexible fibreoptic-assisted intubation and other difficult airway management techniques. DESIGN Retrospective cohort study. SETTING Tertiary care referral centre. METHODS Two periods of equal length (647 days each) before and after introducing the GlideScope were compared. Information about patients who were intubated using nondirect laryngoscopic techniques were analysed. Data were retrieved from the anaesthesia and hospital information management systems. RESULTS Difficult airway management techniques were used in 235/8306 (2.8%) patients before and in 480/8517 (5.6%) (P < 0.0001) patients after the introduction of the GlideScope. There was an overall 44.4% reduction in use of flexible fibreoptic bronchoscopy after GlideScope introduction [before 149/8306 (1.8%); after 85/8517 (1.0%), P < 0.0001]. The GlideScope replaced flexible fibreoptic bronchoscopy in most cases with expected and unexpected difficult intubation. In patients with limited mouth opening, flexible fibreoptic bronchoscopy was still mostly the first choice after the introduction of the GlideScope. There was a 70% reduction in the use of other difficult intubation techniques after the introduction of the GlideScope [before 84/8306 (1.0%); after 22/8517 (0.3%), P < 0.0001)]. CONCLUSION The GlideScope videolaryngoscope replaced flexible fibreoptic bronchoscopy for most patients with expected and unexpected difficult intubation. In the case of limited mouth opening, flexible fibreoptic bronchoscopy was still the first choice after the introduction of the GlideScope. The reduced use of flexible fibreoptic bronchoscopy raises concerns that residents may not be adequately trained in this essential airway management technique. GlideScope use was disproportionately greater than the reduction in the use of flexible fibreoptic bronchoscopy and other difficult intubation techniques. This may be attributed to resident teaching and use in patients with low-to-moderate suspicion of difficult intubation.
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