Characterisation of the fluorescence from freshwater, planktonic bacteria

Amino acid-like fluorescence has been used as an indicator of biological activity in wastewater effluent and in natural waters, and can be detected using fluorescence spectroscopy. Little or no work has been able to state conclusively that these so called 'amino acid-like' fluorophores are associated with proteins present as a result of bacterial activity. This work aims to ascertain whether bacteria are one possible cause of these 'amino acid-like' peaks observed in natural waters. In addition, fluorescence derived solely from one bacterial source was determined as a function of the growth time and temperature. The bacterium Pseudomonas aeruginosa was isolated from the urban River Tame, Birmingham, UK, and planktonic bacteria were grown in sterile, sealed glass jars, in 100 ml growth media. Bacteria were grown at 11, 25 and 37 degrees C, over a maximum of 10 days. A 3D Excitation-Emission Matrix (EEM) plot was generated from fluorescence analysis of the samples. Both tryptophan and tyrosine-like fluorescence, resembling that observed in natural and waste waters, was observed in these samples, indicating that observed fluorescence signals from aquatic systems in the literature were of biotic origin. Significant differences in fluorescence signals were obtained from planktonic cells grown at different temperatures. At 25 and 37 degrees C, cells were found to produce predominantly tryptophan-like fluorescence, with some tyrosine-like fluorescence also detected. A further unknown fluorophore was also detected (emission wavelength of approximately 460 nm, with three excitation centres at 225, 260 and 390 nm), likely to be a bacterially produced metabolite. At 11 degrees C, a more environmentally realistic temperature in temperate environments, quantitative and qualitative differences were observed in fluorescence signals when compared with the higher temperatures, indicating that laboratory observations conducted at higher temperatures may not be easily used to interpret environmental processes.

Outbreak of low pathogenicity H7N3 avian influenza in UK, including associated case of human conjunctivitis

On 26 April 2006, the veterinary authorities in the United Kingdom reported that there had been an outbreak of avian influenza type A/H7 among a 35 000-bird housed poultry flock in eastern England, United Kingdom.

Fractionation of Freshwater Colloids and Particles by SPLITT: Analysis by Electron Microscopy and 3D Excitation−Emission Matrix Fluorescence

This paper reports the first application of a combined approach utilizing split-flow thin-cell (SPLITT) separation to size fractionate natural aquatic colloids and particles collected from freshwater samples. No sample preconcentration was performed although some samples were investigated after alteration of the ambient pH. The unfractionated and fractionated samples were analyzed by scanning electron microscopy (SEM), environmental SEM, and 3D excitation emission matrix fluorescence. Qualitative and quantitative results by microscopy indicated that SPLITT produces well-resolved fractionations at appropriate sizes but with some perturbation of the sample. In addition, tryptophan-like fluorescence was shown to be caused by different organic moieties compared with humic-like and fulvic-like fluorescence. Tryptophan-like fluorescence intensity is found mainly in the particulate material but is not pH dependent, while humic- and fulvic-like fluorescence intensities are dependent on pH but not on size. Fulvic-like fluorescence intensity normalized to absorbance, related to fluorescence efficiency and molar mass, varies with size.

Extraoral removal of a lower third molar tooth

This case report illustrates an example of when an extraoral approach was successfully used to remove a lower left third molar.

Development and application of functional assays for freshwater dissolved organic matter

A series of 11 standardised, reproducible, assays have been developed of physico-chemical functions of dissolved organic matter (DOM) in freshwaters. The assays provide quantitative information on light absorption, fluorescence, photochemical fading, pH buffering, copper binding, benzo(a)pyrene binding, hydrophilicity and adsorption to alumina. To obtain DOM for the assays, a 45 L sample of filtered freshwater was rotary-evaporated to reduce the volume to ca. 500 cm3. The concentrate was then passed through a strong cation exchanger, in the Na+ form, to remove alkaline-earth cations, and then through 0.7 and 0.2 microm filters. Eight samples, two each from a lake and three streamwaters, were processed. The yields of dissolved organic carbon (DOC) ranged from 70% to 107% (average 91%). The samples of DOM, stored in the dark at 4 degrees C, retained their functional assay characteristics for up to 7 months. When assaying the concentrates, parallel assays were performed with Suwannee River fulvic acid (SRFA), as a quality control standard. For most of the assays, the results for eight freshwater DOM samples are similar to those obtained with SRFA, the chief exception being the greater hydrophilicity of the DOM samples. For eight of the assays, variability among the DOM samples is significantly (p < 0.01) greater than can be explained by analytical error, i.e. by comparison with results for the SRFA quality standard; the three exceptional assays are photochemical fading, copper binding and benzo(a)pyrene binding. The two lakewater samples studied gave the most extreme assay results, probably because of the influence of phytoplankton-derived DOM. Significant correlations of hydrophilicity and adsorption with optical absorbance may mean that some DOM functional properties can be predicted from comparatively simple measurements.

Bayesian projections: what are the effects of excluding data from younger age groups?

Bayesian age-period-cohort models are used increasingly to project cancer incidence and mortality rates. Data for younger age groups for which rates are low are often discarded from the analysis. The authors explored the effect of excluding these data, in terms of the precision and accuracy of projections, for selected cancer mortality data sets. Projections were made by using a generalized Bayesian age-period-cohort model. Smoothing was applied to each time scale to reduce random variation between adjacent parameter estimates. The sum of squared standardized residuals was used to assess the accuracy of projections, and 90% credible intervals were calculated to assess precision. For the data sets considered, inclusion of all age groups in the analysis provided more precise age-standardized and age-specific projections as well as more accurate age-specific projections for younger age groups. An overall improvement in the accuracy of age-standardized rates was demonstrated for males but not females, which may suggest that analysis of the full data set is beneficial when projecting cancer rates with strong cohort effects.

Hypotension and Eosinophilia with Atorvastatin

A case report of a 67-year-old man who suffered a hypersensitivity reaction to atorvastatin is described. He suffered collapse and was in shock characterised by marked hypotension, facial oedema and eosinophilia. His initial condition led the surgeons to think he might have had an abdominal sepsis. The reaction with angio-oedema reoccurred on rechallenge. The literature on statin hypersensitivity reactions which can occur several months after commencing therapy is reviewed. Although the estimated prevalence is rare (0.1%), prescribers and pharmacists should be aware of this important reaction which can be quite debilitating.

Is a large-scale DNA-based inventory of ancient life possible?

A complete DNA-based inventory of the Earth's present biota using large-scale high-throughput DNA sequencing of signature region(s) (DNA barcoding) is an ambitious proposal rivaling the Human Genome Project. We examine whether this approach will also enable us to assess the past diversity of the earth's biota. To test this, we sequenced the 5' terminus of the mitochondrial cytochrome c oxidase I (COI) gene of individuals belonging to a group of extinct ratite birds, the moa of New Zealand. Moa comprised a large number of taxa that radiated in isolation on this oceanic landmass. Using a phylogenetic approach based on a large data set including protein coding and 12S DNA sequences as well as morphology, we now have precise information about the number of moa species that once existed. We show that each of the moa species detected using this extensive data set has a unique COI barcode(s) and that they all show low levels of within-species COI variation. Consequently, we conclude that COI sequences accurately identify the species discovered using the larger data set. Hence, more generally, this study suggests that DNA barcoding might also help us detect other extinct animal species and that a large-scale inventory of ancient life is possible.

Catchment-scale fluorescence water quality determination

Chemical water quality determinants and river water fluorescence were determined on the River Tyne, northeast England. Statistically significant relationships between nitrate (r = 0.87), phosphate (r = 0.80), ammonia (r = 0.70), biochemical oxygen demand (BOD) (r = 0.85) and dissolved oxygen (r = -0.65) and tryptophan-like fluorescence intensity were observed. The strongest correlations are between tryptophan-like intensity and nitrate and phosphate, which in the Tyne catchment derive predominantly from point and diffuse source sewage inputs. The correlation between BOD and the tryptophan-like fluorescence intensity suggests that this fluorescence centre is related to the bioavailable or fluorescence intensity and ammonia concentration and dissolved oxygen. The weaker correlation with ammonia is due to good ammonia treatment within the wastewater treatment plants within the catchment, and that with dissolved oxygen due to the natural aeration of the river such that this is not a good indicator of water quality. Mean annual tryptophan-like fluorescence intensity, measured by both bench and portable spectrometers, agrees well with the General Water Quality Assessment as determined by the England and Wales environmental regulators, the Environment Agency.

Perioperative cytokines during orthotopic liver transplantation without venovenous bypass

Since most of studies investigating cytokine levels during human orthotopic liver transplantation used venovenous bypass (VVB), it may be difficult to distinguish between the increase in proinflammatory mediators induced by VVB, by ischemia-reperfusion injury or by splanchnic venous congestion in the anhepatic phase. The goal of this investigation was to assess the levels of interleukin-6 (IL-6) and soluble interleukin-2 receptors (sIL-2r) during OLT procedures routinely performed without VVB.

PATIENTS AND METHODS

Twenty-one consecutive patients underwent OLT with cross clamping of the inferior caval vein without VVB. Soluble IL-2r concentrations were measured by means of luminescence enzyme immunometric assay and IL-6 by means of a sequential immunometric assay. Time points (TP) of sampling were before induction of anesthesia (TP1), after cross-clamping of the inferior vena cava (TP2), 15 minutes after reperfusion (TP3), and 24 hours after the transplant procedure (TP4).

RESULTS

Soluble IL-2r increased significantly 24 hours after transplantation (P =.02) compared to TP1, TP2, and TP3. IL-6 increased significantly during the anhepatic period (TP2 vs TP1, P =.003) and again in the reperfusion period (TP2 vs TP3, P =.002). Twenty-four hours after surgery IL-6 declined significantly (TP3 vs TP4, P =.001), but remained significantly higher (P = 0.04) compared to TP1. Furthermore, we examined the relative changes (DeltaTP %) in perioperative levels of cytokines compared with those previously published in studies using VVB. We observed higher values of DeltaTP % of IL-6 in TP2 and TP4 among our group of patient without VVB. The data on sIL-2r were similar, suggesting no major effects of the operative technique on sIL-2r levels.

CONCLUSION

The two interleukins showed different perioperative trends. Our data suggest that cross clamping contributes more to cell activation, namely, increased release of IL-6 in the anhepatic phase than the use of VVB. However, no major differences were observed during the reperfusion period. The extent of clinical effect on graft function of higher IL-6 levels in the anhepatic period among recipients not supported with VVB remains to be clarified.

Portal Vein Thrombosis and Pancreatic Failure

We report a case of a child with portal vein thrombosis presenting with protein losing enteropathy. Helater developed exocrine and endocrine pancreatic failure. This association has not been reported before.

Epstein-Barr virus-related post-transplant lymphoproliferative disorder with t(9;14)(p11-12;q32)

The immunoglobulin heavy chain gene locus on 14q32 is known to be involved in translocations that are associated with B-lymphoproliferative disorders, typically Burkitt lymphoma and B-cell acute lymphoblastic leukemia. Several cytogenetic abnormalities have been described in post-transplant lymphoproliferatve disease (PTLD), some of which include this locus. To our knowledge, we report the first case of translocation t(9;14)(p11-12;q32) in a PTLD that developed after orthoptic liver transplantation.

Precise dating of Dansgaard-Oeschger climate oscillations in western Europe from stalagmite data

The signature of Dansgaard-Oeschger events--millennial-scale abrupt climate oscillations during the last glacial period--is well established in ice cores and marine records. But the effects of such events in continental settings are not as clear, and their absolute chronology is uncertain beyond the limit of (14)C dating and annual layer counting for marine records and ice cores, respectively. Here we present carbon and oxygen isotope records from a stalagmite collected in southwest France which have been precisely dated using 234U/230Th ratios. We find rapid climate oscillations coincident with the established Dansgaard-Oeschger events between 83,000 and 32,000 years ago in both isotope records. The oxygen isotope signature is similar to a record from Soreq cave, Israel, and deep-sea records, indicating the large spatial scale of the climate oscillations. The signal in the carbon isotopes gives evidence of drastic and rapid vegetation changes in western Europe, an important site in human cultural evolution. We also find evidence for a long phase of extremely cold climate in southwest France between 61.2 +/- 0.6 and 67.4 +/- 0.9 kyr ago.

The impact of roster changes on absenteeism and incident frequency in an Australian coal mine

BACKGROUND

The occupational health and safety implications associated with compressed and extended work periods have not been fully explored in the mining sector.

AIMS

To examine the impact on employee health and safety of changes to the roster system in an Australian coal mine.

METHODS

Absenteeism and incident frequency rate data were collected over a 33 month period that covered three different roster schedules. Period 1 covered the original 8-hour/7-day roster. Period 2 covered a 12-month period under a 12-hour/7-day schedule, and period 3 covered a 12-month period during which a roster that scheduled shifts only on weekdays, with uncapped overtime on weekends and days off (12-hour/5-day) was in place. Data were collected and analysed from the maintenance, mining, and coal preparation plant (CPP) sectors.

RESULTS

The only significant change in absenteeism rates was an increase in the maintenance sector in the third data collection period. Absenteeism rates in the mining and CPP sectors were not different between data collection periods. The increase in the maintenance sector may be owing to: (1) a greater requirement for maintenance employees to perform overtime as a result of the roster change compared to other employee groups; or (2) greater monotony associated with extended work periods for maintenance employees compared to others. After the first roster change, accident incident frequency decreased in the CPP sector but not in the other sectors. There was no effect on incident frequency after the second roster change in any sector.

CONCLUSIONS

The current study did not find significant negative effects of a 12-hour pattern, when compared to an 8-hour system. However, when unregulated and excessive overtime was introduced as part of the 12-hour/5-day roster, absenteeism rates were increased in the maintenance sector. The combination of excessive work hours and lack of consultation with employees regarding the second change may have contributed to the overall negative effects.