The presence of bacteria varies between colorectal adenocarcinomas, precursor lesions and non-malignant tissue.

BACKGROUND: A causal association has been suggested between certain bacteria and colorectal cancer (CRC). Only a few studies have, however, investigated the presence of these bacteria directly in colon tissue with conflicting results. It is thus uncertain which role they may have in prognosis and carcinogenesis of CRC. METHODS: Formalin-fixed and paraffin-embedded (FFPE) colorectal tissue samples from patients diagnosed with colorectal cancer (CRC)(tumor and paired normal tissue, n = 99), adenomas (n = 96), or diverticular disease (n = 104) were tested for the presence and bacterial load of Streptococcus gallolyticus (S. gallolyticus), Fusobacterium nucleatum (F. nucleatum), and Bacteroides fragilis (B. fragilis) using quantitative PCR. A subsequent broader search was conducted on a subset of samples using 16S ribosomal RNA gene sequencing. Finally, to evaluate the prognostic value, the bacterial status was compared to patient outcome. RESULTS: S. gallolyticus was not detected by qPCR in any of the investigated tissue samples and F. nucleatum and B. fragilis were found to be equally distributed in tumors, paired normal tissue, and diverticula, but significantly less present in adenomas compared to both tumors and diverticula. Neither, F. nucleatum nor B. fragilis status affected the five-year prognosis of the patients. The 16S rRNA gene sequencing data revealed that tumors were associated with the Prevotella genus while conversely adenomas and diverticula were associated with Acinetobacter genus. CONCLUSION: These findings do not support a role of F. nucleatum or B. fragilis during colorectal beginning, while S. gallolyticus was not implicated in the colorectal tissue of a Danish population. A potential role of the bacterial genera Prevotella and Acinetobacter was indicated, and requires further investigations.

Cutavirus in Cutaneous Malignant Melanoma.

A novel human protoparvovirus related to human bufavirus and preliminarily named cutavirus has been discovered. We detected cutavirus in a sample of cutaneous malignant melanoma by using viral enrichment and high-throughput sequencing. The role of cutaviruses in cutaneous cancers remains to be investigated.

Antibody response to influenza A(H1N1)pdm09 in vaccinated, serologically infected and unaffected pregnant women and their newborns.

OBJECTIVE: To evaluate the serological response in pregnant Danish women immunized during the 2009 pandemic by serologic infection or by vaccination with influenza A(H1N1) Pandemrix(®) and describe levels of passively acquired maternal antibody in their offspring. DESIGN: Observational cohort study. SETTING: Department of Obstetrics, Aarhus University Hospital, Skejby, Denmark, October to December 2009. POPULATION: Pregnant women and their offspring METHODS: Serological analysis of antibodies to influenza A(H1N1)pdm09 by hemagglutination inhibition assay in 197 women and their offspring. Blood samples were collected consecutively at delivery from the mother and the umbilical cord. In a subgroup of 124 of the 197 women, an additional blood sample from gestational weeks 9-12 was available for analysis. MAIN OUTCOME MEASURES: Seroconversion, geometric mean titer, geometric mean-fold rise and protective antibodies. RESULTS: 33 of the 124 subgroup women (27%) seroconverted during pregnancy, 79% after vaccination and 17% after serologic infection (p < 0.001). The geometric mean titer after delivery in non-vaccinated, non-serologically infected women was 17.1 (95%CI 15.7-18.6). The geometric mean titer increased significantly after serologic infection with H1N1 [76.5 (95%CI 51.3-113.9), p < 0.001] and after vaccination [589.6 (95%CI 339.3-1024.7), p < 0.001]. The geometric mean-fold rise (mother at delivery/mother early pregnancy) was significantly higher after vaccination [2.23 (1.93-2.54)] than after serologic infection [1.73 (1.59-1.87), p = 0.013]. In newborns of vaccinated mothers, 89.5% had protective antibody levels compared with 15.8% in newborns of serologically infected mothers (p < 0.001). CONCLUSIONS: Influenza vaccination during pregnancy confers passive immunity to the newborn.

Mechanistic basis for high stereoselectivity and broad substrate scope in the (salen)Co(III)-catalyzed hydrolytic kinetic resolution.

In the (salen)Co(III)-catalyzed hydrolytic kinetic resolution (HKR) of terminal epoxides, the rate- and stereoselectivity-determining epoxide ring-opening step occurs by a cooperative bimetallic mechanism with one Co(III) complex acting as a Lewis acid and another serving to deliver the hydroxide nucleophile. In this paper, we analyze the basis for the extraordinarily high stereoselectivity and broad substrate scope observed in the HKR. We demonstrate that the stereochemistry of each of the two (salen)Co(III) complexes in the rate-determining transition structure is important for productive catalysis: a measurable rate of hydrolysis occurs only if the absolute stereochemistry of each of these (salen)Co(III) complexes is the same. Experimental and computational studies provide strong evidence that stereochemical communication in the HKR is mediated by the stepped conformation of the salen ligand, and not the shape of the chiral diamine backbone of the ligand. A detailed computational analysis reveals that the epoxide binds the Lewis acidic Co(III) complex in a well-defined geometry imposed by stereoelectronic rather than steric effects. This insight serves as the basis of a complete stereochemical and transition structure model that sheds light on the reasons for the broad substrate generality of the HKR.

Seasonal methane oxidation potential in manure crusts.

Organic crusts on liquid manure storage tanks harbor ammonia- and nitrite-resistant methane oxidizers and may significantly reduce methane emissions. Methane oxidation potential (0.6 mol CH(4) m(-2) day(-1)) peaked during fall and winter, after 4 months of crust development. Consequences for methane mitigation potential of crusts are discussed.

Genetic diversity among pandemic 2009 influenza viruses isolated from a transmission chain.

BACKGROUND: Influenza viruses such as swine-origin influenza A(H1N1) virus (A(H1N1)pdm09) generate genetic diversity due to the high error rate of their RNA polymerase, often resulting in mixed genotype populations (intra-host variants) within a single infection. This variation helps influenza to rapidly respond to selection pressures, such as those imposed by the immunological host response and antiviral therapy. We have applied deep sequencing to characterize influenza intra-host variation in a transmission chain consisting of three cases due to oseltamivir-sensitive viruses, and one derived oseltamivir-resistant case. METHODS: Following detection of the A(H1N1)pdm09 infections, we deep-sequenced the complete NA gene from two of the oseltamivir-sensitive virus-infected cases, and all eight gene segments of the viruses causing the remaining two cases. RESULTS: No evidence for the resistance-causing mutation (resulting in NA H275Y substitution) was observed in the oseltamivir-sensitive cases. Furthermore, deep sequencing revealed a subpopulation of oseltamivir-sensitive viruses in the case carrying resistant viruses. We detected higher levels of intra-host variation in the case carrying oseltamivir-resistant viruses than in those infected with oseltamivir-sensitive viruses. CONCLUSIONS: Oseltamivir-resistance was only detected after prophylaxis with oseltamivir, suggesting that the mutation was selected for as a result of antiviral intervention. The persisting oseltamivir-sensitive virus population in the case carrying resistant viruses suggests either that a small proportion survive the treatment, or that the oseltamivir-sensitive virus rapidly re-establishes itself in the virus population after the bottleneck. Moreover, the increased intra-host variation in the oseltamivir-resistant case is consistent with the hypothesis that the population diversity of a RNA virus can increase rapidly following a population bottleneck.

Oseltamivir-resistant pandemic H1N1/2009 influenza virus possesses lower transmissibility and fitness in ferrets.

The neuraminidase (NA) inhibitor oseltamivir offers an important immediate option for the control of influenza, and its clinical use has increased substantially during the recent H1N1 pandemic. In view of the high prevalence of oseltamivir-resistant seasonal H1N1 influenza viruses in 2007-2008, there is an urgent need to characterize the transmissibility and fitness of oseltamivir-resistant H1N1/2009 viruses, although resistant variants have been isolated at a low rate. Here we studied the transmissibility of a closely matched pair of pandemic H1N1/2009 clinical isolates, one oseltamivir-sensitive and one resistant, in the ferret model. The resistant H275Y mutant was derived from a patient on oseltamivir prophylaxis and was the first oseltamivir-resistant isolate of the pandemic virus. Full genome sequencing revealed that the pair of viruses differed only at NA amino acid position 275. We found that the oseltamivir-resistant H1N1/2009 virus was not transmitted efficiently in ferrets via respiratory droplets (0/2), while it retained efficient transmission via direct contact (2/2). The sensitive H1N1/2009 virus was efficiently transmitted via both routes (2/2 and 1/2, respectively). The wild-type H1N1/2009 and the resistant mutant appeared to cause a similar disease course in ferrets without apparent attenuation of clinical signs. We compared viral fitness within the host by co-infecting a ferret with oseltamivir-sensitive and -resistant H1N1/2009 viruses and found that the resistant virus showed less growth capability (fitness). The NA of the resistant virus showed reduced substrate-binding affinity and catalytic activity in vitro and delayed initial growth in MDCK and MDCK-SIAT1 cells. These findings may in part explain its less efficient transmission. The fact that the oseltamivir-resistant H1N1/2009 virus retained efficient transmission through direct contact underlines the necessity of continuous monitoring of drug resistance and characterization of possible evolving viral proteins during the pandemic.

Mechanistic basis for high reactivity of (salen)Co-OTs in the hydrolytic kinetic resolution of terminal epoxides.

The (salen)Co(III)-catalyzed hydrolytic kinetic resolution (HKR) of terminal epoxides is a bimetallic process with a rate controlled by partitioning between a nucleophilic (salen)Co-OH catalyst and a Lewis acidic (salen)Co-X catalyst. The commonly used (salen)Co-OAc and (salen)Co-Cl precatalysts undergo complete and irreversible counterion addition to epoxide during the course of the epoxide hydrolysis reaction, resulting in quantitative formation of weakly Lewis acidic (salen)Co-OH and severely diminished reaction rates in the late stages of HKR reactions. In contrast, (salen)Co-OTs maintains high reactivity over the entire course of HKR reactions. We describe here an investigation of catalyst partitioning with different (salen)Co-X precatalysts and demonstrate that counterion addition to epoxide is reversible in the case of the (salen)Co-OTs. This reversible counterion addition results in stable partitioning between nucleophilic and Lewis acidic catalyst species, allowing highly efficient catalysis throughout the course of the HKR reaction.

Significantly higher use of polypharmacy in elderly with hip fracture treated with psychotropics.

INTRODUCTION: The high prevalence of chronic medical conditions among older adults leads to an increased use of prescription medications and a heightened risk of polypharmacy, raising the risk of falls and fractures. Psychotropic medications influence balance, and therefore our aim was to describe the use of psychotropic medications and the association with polypharmacy in elderly patients with a hip fracture. METHODS: A retrospective study of 200 patients aged 65 years or more admitted consecutively with a hip fracture. RESULTS: In total, 98 of the 200 patients used psychotropic medications. These 98 patients used a higher number of drugs at the time of admission (an average of eight (6-11) versus six (3-10), p less-than0.001), had a higher risk of using five or more medications (odds ratio (OR) = 5.9; 95% confidence interval (CI): 2.75-12.7; p less-than 0.001) and a higher risk of using ten or more medications (OR = 1.9; 95% CI: 1.05-3.5; p = 0.03). Furthermore, they were more likely to use analgesics (65.3% versus 48.0%; p = 0.01) and medications targeting the gastrointestinal tract (59.1% versus 40.2%; p = 0.01). CONCLUSIONS: Psychotropic medication use was frequent in elderly patients with a hip fracture and strongly associated with polypharmacy. Psychotropic medications may potentially be a trigger to perform medication review in elderly patients to prevent re-occurrence hip fractures. FUNDING: none. TRIAL REGISTRATION: not relevant.

Efficacy of the TMPRSS2 inhibitor camostat mesilate in patients hospitalized with Covid-19-a double-blind randomized controlled trial.

BACKGROUND: The trans-membrane protease serine 2 (TMPRSS2) is essential for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) cell entry and infection. Efficacy and safety of TMPRSS2 inhibitors in patients with coronavirus disease 2019 (Covid-19) have not been evaluated in randomized trials. METHODS: We conducted an investigator-initiated, double-blind, randomized, placebo-controlled multicenter trial in patients hospitalized with confirmed SARS-CoV-2 infection from April 4, to December 31, 2020. Within 48 h of admission, participants were randomly assigned in a 2:1 ratio to receive the TMPRSS2 inhibitor camostat mesilate 200 mg three times daily for 5 days or placebo. The primary outcome was time to discharge or clinical improvement measured as ≥2 points improvement on a 7-point ordinal scale. Other outcomes included 30-day mortality, safety and change in oropharyngeal viral load. FINDINGS: 137 patients were assigned to receive camostat mesilate and 68 to placebo. Median time to clinical improvement was 5 days (interquartile range [IQR], 3 to 7) in the camostat group and 5 days (IQR, 2 to 10) in the placebo group (P = 0·31). The hazard ratio for 30-day mortality in the camostat compared with the placebo group was 0·82 (95% confidence interval [CI], 0·24 to 2·79; P = 0·75). The frequency of adverse events was similar in the two groups. Median change in viral load from baseline to day 5 in the camostat group was -0·22 log10 copies/mL (p <0·05) and -0·82 log10 in the placebo group (P <0·05). INTERPRETATION: Under this protocol, camostat mesilate treatment was not associated with increased adverse events during hospitalization for Covid-19 and did not affect time to clinical improvement, progression to ICU admission or mortality. ClinicalTrials.gov Identifier: NCT04321096. EudraCT Number: 2020-001200-42.

Oxygen distribution and potential ammonia oxidation in floating, liquid manure crusts.

Floating, organic crusts on liquid manure, stored as a result of animal production, reduce emission of ammonia (NH3) and other volatile compounds during storage. The occurrence of NO2- and NO3- in the crusts indicate the presence of actively metabolizing NH3-oxidizing bacteria (AOB) which may be partly responsible for this mitigation effect. Six manure tanks with organic covers (straw and natural) were surveyed to investigate the prevalence and potential activity ofAOB and its dependence on the O2 availability in the crust matrix as studied by electrochemical profiling. Oxygen penetration varied from <1 mm in young, poorly developed natural crusts and old straw crusts, to several centimeters in the old natural crusts. The AOB were ubiquitously present in all crusts investigated, but nitrifying activity could only be detected in old natural crusts and young straw crust with high O2 availability. In old natural crusts, total potential NH3 oxidation rates were similar to reported fluxes of NH3 from slurry without surface crust. These results indicate that old, natural surface crusts may develop into a porous matrix with high O2 availability that harbors an active population of aerobic microorganisms, including AOB. The microbial activity may thus contribute to a considerable reduction of ammonia emissions from slurry tanks with well-developed crusts.

Greenhouse gas microbiology in wet and dry straw crust covering pig slurry.

Liquid manure (slurry) storages are sources of gases such as ammonia (NH(3)) and methane (CH(4)). Danish slurry storages are required to be covered to reduce NH(3) emissions and often a floating crust of straw is applied. This study investigated whether physical properties of the crust or crust microbiology had an effect on the emission of the potent greenhouse gases CH(4) and nitrous oxide (N(2)O) when crust moisture was manipulated ("dry", "moderate", and "wet"). The dry crust had the deepest oxygen penetration (45 mm as compared to 20 mm in the wet treatment) as measured with microsensors, the highest amounts of nitrogen oxides (NO(2)(-) and NO(3)(-)) (up to 36 mumol g(-1) wet weight) and the highest emissions of N(2)O and CH(4). Fluorescent in situ hybridization and gene-specific polymerase chain reaction (PCR) were used to detect occurrence of bacterial groups. Ammonia-oxidizing bacteria (AOB) were abundant in all three crust types, whereas nitrite-oxidizing bacteria (NOB) were undetectable and methane-oxidizing bacteria (MOB) were only sparsely present in the wet treatment. A change to anoxia did not affect the CH(4) emission indicating the virtual absence of aerobic methane oxidation in the investigated 2-mo old crusts. However, an increase in N(2)O emission was observed in all crusted treatments exposed to anoxia, and this was probably a result of denitrification based on NO(x)(-) that had accumulated in the crust during oxic conditions. To reduce overall greenhouse gas emissions, floating crust should be managed to optimize conditions for methanotrophs.

The Potential of Biogas; the Solution to Energy Storage.

Energy storage will be essential for balancing the renewable energy systems of tomorrow, especially if excess electricity from wind and solar power requires immediate utilization. The use of biogas as a carbon source can generate carbon dioxide-neutral carbon-based energy carriers, such as methane or methanol. The utilization of biogas today is limited to the generation of heat/power or biomethane (first-generation upgrading); both processes disregard the potential of the coproduced carbon dioxide during the fermentation process. By using renewable energy, biogas upgrading systems can convert carbon dioxide into hydrocarbon-based high-energy-density fuels, which can replace fossil-based fuels for applications in which they are hard to decarbonize. The possibilities for the future utilization of biogas are discussed, and the terminology for "second-generation upgrading" is introduced to help research and development within this field. It is believed that second-generation upgrading of biogas will have a huge potential for dynamic energy storage.

The evolution of human influenza A viruses from 1999 to 2006: a complete genome study.

BACKGROUND: Knowledge about the complete genome constellation of seasonal influenza A viruses from different countries is valuable for monitoring and understanding of the evolution and migration of strains. Few complete genome sequences of influenza A viruses from Europe are publicly available at the present time and there have been few longitudinal genome studies of human influenza A viruses. We have studied the evolution of circulating human H3N2, H1N1 and H1N2 influenza A viruses from 1999 to 2006, we analysed 234 Danish human influenza A viruses and characterised 24 complete genomes. RESULTS: H3N2 was the prevalent strain in Denmark during the study period, but H1N1 dominated the 2000-2001 season. H1N2 viruses were first observed in Denmark in 2002-2003. After years of little genetic change in the H1N1 viruses the 2005-2006 season presented H1N1 of greater variability than before. This indicates that H1N1 viruses are evolving and that H1N1 soon is likely to be the prevalent strain again. Generally, the influenza A haemagglutinin (HA) of H3N2 viruses formed seasonal phylogenetic clusters. Different lineages co-circulating within the same season were also observed. The evolution has been stochastic, influenced by small "jumps" in genetic distance rather than constant drift, especially with the introduction of the Fujian-like viruses in 2002-2003. Also evolutionary stasis-periods were observed which might indicate well fit viruses. The evolution of H3N2 viruses have also been influenced by gene reassortments between lineages from different seasons. None of the influenza genes were influenced by strong positive selection pressure. The antigenic site B in H3N2 HA was the preferred site for genetic change during the study period probably because the site A has been masked by glycosylations. Substitutions at CTL-epitopes in the genes coding for the neuraminidase (NA), polymerase acidic protein (PA), matrix protein 1 (M1), non-structural protein 1 (NS1) and especially the nucleoprotein (NP) were observed. The N-linked glycosylation pattern varied during the study period and the H3N2 isolates from 2004 to 2006 were highly glycosylated with ten predicted sequons in HA, the highest amount of glycosylations observed in this study period. CONCLUSION: The present study is the first to our knowledge to characterise the evolution of complete genomes of influenza A H3N2, H1N1 and H1N2 isolates from Europe over a time period of seven years from 1999 to 2006. More precise knowledge about the circulating strains may have implications for predicting the following season strains and thereby better matching the vaccine composition.

Improving Medication Safety in Psychiatry - A Controlled Intervention Study of Nurse Involvement in Avoidance of Potentially Inappropriate Prescriptions.

The aim of this controlled, before-and-after study in the Department of Psychiatry in a university hospital in Denmark was to examine the potential effects and characteristics of nurses reviewing psychiatric patients' medication records to identify potentially inappropriate prescriptions (PIPs). The control group and the intervention group each consisted of two bed units chosen based on patients' diagnoses and age categories. There were 396 patients (age ≥18 years) included in the study. Senior clinical pharmacology physicians performed medication reviews for all patients in the study; these medication reviews were considered gold standard. The intervention group: nurses were given a pharmacology course after which the nurses reviewed medication lists and subsequently conferred any identified PIPs with physicians. The control group: medication was reviewed as usual and nurses did not participate. Primary outcome measure was the potential difference in PIPs between the control group and the intervention group, analysed in two ways: (i) difference in mean number of PIPs and (ii) difference in number of patients exposed to ≥1 PIP, using regression analysis with an approximated difference-in-difference (DID) approach. Secondary outcome measure was characteristics of PIPs where physicians responded to nurse-identified PIPs. The DID between intervention group and control group for mean number of PIPs per patient was -0.23 (-1.07 to 0.60), and for number of patients receiving ≥1 PIP, the odds ratio was 0.61 (0.25 to 1.46). Physicians changed most prescriptions in the category interaction between drugs. Nurses could not significantly reduce the prevalence of PIPs for psychiatric patients.

Aetiology and prediction of pneumonia in lower respiratory tract infection in primary care.

BACKGROUND: Knowledge of predominant pathogens and their association with outcome are of importance for the management of lower respiratory tract infection (LRTI). As antibiotic therapy is indicated in pneumonia and not in acute bronchitis, a predictor of pneumonia is needed. AIM: To describe the aetiology and outcome of LRTI in adults with pneumonic and adults with non-pneumonic LRTI treated in general practice and to identify predictors of radiographic pneumonia. DESIGN OF STUDY: Prospective, observational study. SETTING: Forty-two general practices and an outpatient clinic at the Department of Infectious Diseases, Odense University Hospital, Denmark. METHOD: A total of 364 adults diagnosed with community-acquired LRTI by their GP were studied with chest radiography, vital signs, biochemical markers of inflammation (C-reactive protein [CRP] and leukocyte count), and microbiological examinations. Primary outcome measure was hospitalisation within 4 weeks. RESULTS: Pneumonia was radiographically verified in 48 of 364 patients (13%). Bacterial infection was seen more often in patients with pneumonia (33% versus 17%, P<0.001), and viral infection more often in non-pneumonic patients (26% versus 13%, P<0.05). Hospitalisation was more common in patients with pneumonia compared to non-pneumonic patients (19 versus 3%, P<0.001); and in patients with pneumococcal infection compared with patients without pneumococcal infection (26 versus 4%, P = 0.001). The positive predictive value of GPs' diagnosis of pneumonia was low (0.23), but the vital signs, CRP, and leukocyte count had comparably low positive predictive values (0.23-0.30). CONCLUSION: Streptococcus pneumoniae was the most common bacterial pathogen. The risk of hospitalisation was highest among patients with pneumonia or pneumococcal infection; this emphasises the importance of coverage of S. pneumoniae when treatment is indicated. CRP should not be introduced for diagnosis of radiographic pneumonia in general practice before its use has been investigated in prospective, controlled intervention trials using CRP-guided treatment algorithms.

Procalcitonin versus C-reactive protein for predicting pneumonia in adults with lower respiratory tract infection in primary care.

BACKGROUND: The role of procalcitonin in diagnosing bacterial infection has mainly been studied in patients with severe infections. There is no study on the value of procalcitonin measurements in adults with lower respiratory tract infection (LRTI) treated in primary care. AIM: To evaluate the accuracy of plasma procalcitonin in predicting radiographic pneumonia, bacterial infection, and adverse outcome in a population of adults with LRTI treated in primary care. DESIGN OF STUDY: Prospective, observational study. SETTING: Forty-two general practices and an outpatient clinic at the Department of Infectious Diseases, Odense University Hospital, Denmark. METHOD: A total of 364 patients with LRTI were prospectively enrolled from 42 general practices. Patients were examined with chest radiography, microbiological analyses, and measurements of C-reactive protein (CRP) and procalcitonin. The outcome measure was hospitalisation within 4 weeks of enrollment. RESULTS: Median procalcitonin was 0.05 ng/ml, which was below the functional sensitivity of the assay (0.06 ng/ml). In predicting radiographic pneumonia, bacterial infection, and hospitalisation, the sensitivities of procalcitonin >0.06 ng/ml were 0.70, 0.51, and 0.67, and of CRP were > or =20 mg/l, 0.73, 0.56, and 0.74 respectively. Corresponding positive predictive values were between 0.09 and 0.28. CONCLUSION: Both procalcitonin >0.06 ng/ml and CRP > or =20 mg/l were associated with radiographic pneumonia, bacterial infection, and subsequent hospitalisation, but positive predictive values were too low for any of the two inflammatory markers to be of use in clinical practice. To measure procalcitonin values accurately in the primary care setting, a more sensitive method is needed, but there was no indication that procalcitonin is superior to CRP in identifying patients with pneumonia, bacterial aetiology, or adverse outcome.

Hydrogen Dynamics in Cyanobacteria Dominated Microbial Mats Measured by Novel Combined H2/H2S and H2/O2 Microsensors.

Hydrogen may accumulate to micromolar concentrations in cyanobacterial mat communities from various environments, but the governing factors for this accumulation are poorly described. We used newly developed sensors allowing for simultaneous measurement of H2S and H2 or O2 and H2 within the same point to elucidate the interactions between oxygen, sulfate reducing bacteria, and H2 producing microbes. After onset of darkness and subsequent change from oxic to anoxic conditions within the uppermost ∼1 mm of the mat, H2 accumulated to concentrations of up to 40 µmol L-1 in the formerly oxic layer, but with high variability among sites and sampling dates. The immediate onset of H2 production after darkening points to fermentation as the main H2 producing process in this mat. The measured profiles indicate that a gradual disappearance of the H2 peak was mainly due to the activity of sulfate reducing bacteria that invaded the formerly oxic surface layer from below, or persisted in an inactive state in the oxic mat during illumination. The absence of significant H2 consumption in the formerly oxic mat during the first ∼30 min after onset of anoxic conditions indicated absence of active sulfate reducers in this layer during the oxic period. Addition of the methanogenesis inhibitor BES led to increase in H2, indicating that methanogens contributed to the consumption of H2. Both H2 formation and consumption seemed unaffected by the presence/absence of H2S.

Viral and atypical bacterial infections in the outpatient pediatric cystic fibrosis clinic.

BACKGROUND: Respiratory viral and atypical bacterial infections are associated with pulmonary exacerbations and hospitalisations in cystic fibrosis patients. We wanted to study the impact of such infections on children attending the outpatient clinic. METHODS: Seventy-five children were followed for 12 months at regular clinic visits. Routine sputum/laryngeal aspirations were tested with PCR for 7 respiratory viruses. Antibodies against C. pneumoniae, M. pneumoniae and B. pertussis were measured every 3-4 months. FEV-1, FEF(25-75) and specific airway resistance, "viral" symptoms and bacterial culture were recorded. RESULTS: Ninety-seven viral and 21 atypical bacterial infections were found. FEV-1 was significantly reduced during viral infection (-12.5%, p=0.048), with the exception of rhinovirus infection. A small change in FEV-1 (-3%) was seen during atypical bacterial infection (p=0.039). Viral and atypical bacterial infections caused no change in type and frequency of bacterial culture. Positive predictive value of "viral symptoms" was low (0.64%). Eight patients received "unnecessary" antibiotics because of viral symptoms. CONCLUSIONS: Some viral infections and atypical bacterial infections affect FEV-1 acutely. Viral infections did not precipitate bacterial infection or change of colonisation. Clinical symptoms failed to diagnose viral infection accurately. Routine surveillance for virus or atypical bacteria seems not to be justified in this patient category.

Uridine recognition motifs of human equilibrative nucleoside transporters 1 and 2 produced in Saccharomyces cerevisiae.

The sugar moiety of nucleosides has been shown to play a major role in permeant-transporter interaction with human equilibrative nucleoside transporters 1 and 2 (hENT1 and hENT2). To better understand the structural requirements for interactions with hENT1 and hENT2, a series of uridine analogs with sugar modifications were subjected to an assay that tested their abilities to inhibit [3H]uridine transport mediated by recombinant hENT1 and hENT2 produced in Saccharomyces cerevisiae. hENT1 displayed higher affinity for uridine than hENT2. Both transporters barely tolerated modifications or inversion of configuration at C(3'). The C(2')-OH at uridine was a structural determinant for uridine-hENT1, but not for uridine-hENT2, interactions. Both transporters were sensitive to modifications at C(5') and hENT2 displayed more tolerance to removal of C(5')-OH than hENT1; addition of an O-methyl group at C(5') greatly reduced interaction with either hENT1 or hENT2. The changes in binding energies between transporter proteins and the different uridine analogs suggested that hENT1 formed strong interactions with C(3')-OH and moderate interactions with C(2')-OH and C(5')-OH of uridine, whereas hENT2 formed strong interactions with C(3')-OH, weak interactions with C(5')-OH, and no interaction with C(2')-OH.