Environmental assessment of landfill gas mitigation using biocover and gas collection with energy utilisation at aging landfills

A life cycle-based environmental assessment was conducted on the mitigation of landfill gas emissions, by implementing biocover and gas collection along with energy utilisation at aging landfills. Based on recent studies about gas generation at Danish landfills, the efficiency of the mitigation technologies involved and the composition of substituted energy production, 15 scenarios were modelled using the EASETECH life cycle assessment model, through which potential environmental impacts in the category "Climate change" were calculated. In all scenarios, biocover and gas collection systems with energy utilisation led to significant environmental improvements compared to the baseline scenario with no emission mitigation action. Scenarios representing biocovers with methane oxidation efficiencies between 70 and 90 % were environmentally superior in terms of climate change impact - in comparison to scenarios with 20-30 years of gas collection and energy utilisation (collection efficiencies between 40 and 80 %). Combining gas collection with energy utilisation and the subsequent installation of a biocover saw major improvements in comparison to where only gas collection and energy utilisation were in effect. Overall, it can be concluded that a biocover under the given assumptions is environmentally more appropriate than gas collection and utilisation at aging landfills, mainly due to methane emissions escaping through the landfill cover during and after the gas collection period playing a crucial role in the latter situation. Maintaining high methane oxidation efficiency for a biocover throughout the lifetime of a landfill is vital for reducing environmental impacts.

Correction to: The Burden of Sarcoidosis Symptoms from a Patient Perspective

The original version of this article unfortunately contained a mistake in coauthor's given name. The abbreviated given name "M.D." for coauthor M.D.P. Elfferich's name has been inadvertently deleted during the production process.

The Burden of Sarcoidosis Symptoms from a Patient Perspective

PURPOSE

The clinical manifestations of sarcoidosis vary widely, depending on the intensity of the inflammation and the organ systems affected. Hence, sarcoidosis patients may suffer from a great variety of symptoms. The aim of this study was to compare the self-reported burden of sarcoidosis patients in Denmark, Germany and the Netherlands, especially the prevalence of fatigue and small fiber neuropathy (SFN)-related symptoms, as well as differences in treatment strategies.

METHODS

A cross-sectional web-based anonymous survey about complaints was conducted among sarcoidosis patients. Patients were invited to take part through the sarcoidosis patient societies as well as through outpatient sarcoidosis clinics in these countries.

RESULTS

The questionnaire was completed by 1072 sarcoidosis patients (152 Danish, 532 German and 388 Dutch). Almost all patients reported having sarcoidosis-associated symptoms (organ-related as well as non-specific, non-organ related). Fatigue was reported by almost all respondents (90%), followed by pulmonary symptoms (72.4%). More than 50% of the respondents were being treated with prednisone, which was comparable in all three countries. In contrast, second- and third-line treatment differed substantially between Denmark, Germany and the Netherlands.

CONCLUSION

Sarcoidosis patients in Denmark, Germany and the Netherlands present with similar self-reported symptoms, organ-related as well as non-specific, non-organ related. Fatigue (90%) and symptoms associated with SFN (86%) were highly prevalent in all three countries.

Structural progression rate decreases over time on serial radiography and magnetic resonance imaging of sacroiliac joints and spine in a five-year follow-up study of patients with ankylosing spondylitis treated with tumour necrosis factor inhibitor

OBJECTIVE

To investigate temporal changes in structural progression assessed by serial conventional radiography and magnetic resonance imaging (MRI) of the sacroiliac joints (SIJs) and spine in patients with ankylosing spondylitis (AS) treated with tumour necrosis factor (TNF) inhibitor for 5 years.

METHOD

Forty-two patients were included and 33 patients were followed for 5 years in a prospective investigator-initiated study. Conventional radiographs were required four times and MRI seven times. The modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS); Spondyloarthritis Research Consortium of Canada (SPARCC) MRI SIJ and Spine Inflammation, and SPARCC MRI SIJ Structural Score (SSS) for Fat, Erosion, Backfill, and Ankylosis; and the Canada-Denmark MRI scores for Spine Inflammation, Fat, Erosion, and New Bone Formation (NBF) were applied.

RESULTS

Compared with baseline, MRI Inflammation had decreased significantly at week 22 (spine)/week 46 (SIJ) and thereafter. MRI SIJ Fat (from week 22), SIJ Ankylosis, Spine NBF, and mSASSS had increased significantly at week 46 and thereafter. SIJ Erosion had decreased from year 2. The annual progression rate in mSASSS was significantly higher during weeks 0-46 compared to week 46 to year 3. In multivariate regression analyses, baseline SIJ Inflammation and Backfill were independent predictors of 5 year progression in SIJ Ankylosis. Spine Erosion predicted progression in Spine NBF. Longitudinally, Ankylosing Spondylitis Disease Activity Score, Bath Ankylosing Spondylitis Disease Activity Index, MRI Spine Inflammation, Fat, and Erosion scores were significantly associated with mSASSS. SIJ Inflammation, Fat, Erosion, and Backfill scores were longitudinally associated with SIJ Ankylosis. Structural progression was not associated with body mass index, smoking, or Assessment of SpondyloArthritis international Society Non-Steroidal Anti-Inflammatory Drug Index.

CONCLUSION

In a 5 year follow-up study of patients with AS treated with TNF inhibitor, structural progression decreased over time.

Investigation of a multi-biomarker disease activity score in rheumatoid arthritis by comparison with magnetic resonance imaging, computed tomography, ultrasonography, and radiography parameters of inflammation and damage

OBJECTIVES

To investigate the multi-biomarker disease activity (MBDA) score by comparison with imaging findings in an investigator-initiated rheumatoid arthritis (RA) trial (HURRAH trial, NCT00696059).

METHOD

Fifty-two patients with established RA initiated adalimumab treatment and had magnetic resonance imaging (MRI), ultrasonography (US), computed tomography (CT), and radiography performed at weeks 0, 26, and 52. Serum samples were analysed using MBDA score assays and associations between clinical measures, MBDA score, and imaging findings were investigated.

RESULTS

The MBDA score correlated significantly with MRI synovitis (rho = 0.65, p < 0.001), MRI bone marrow oedema (rho = 0.36, p = 0.044), and US power Doppler (PD) score at week 26 (rho = 0.35, p = 0.039) but not at week 0 or week 52. In the 15 patients who had achieved a Disease Activity Score based on C-reactive protein (DAS28-CRP) < 2.6 at week 26, MRI and/or US detected subclinical inflammation and 13 (87%) had a moderate/high MBDA score. For the cohort with available data, none of the four patients in MBDA remission (score ≤ 25) at week 26 had progression of imaging damage from baseline to week 52 whereas progression was observed in three out of nine (33%) and seven out of 21 (33%) patients with moderate (30-44) and high (> 44) MBDA scores, respectively.

CONCLUSIONS

In this cohort, the MBDA score correlated poorly with MRI/US inflammation. However, the MBDA score and MRI/US were generally concordant in showing signs of inflammation in most patients in clinical remission during anti-tumour necrosis factor (anti-TNF) therapy. MBDA scores were elevated in all patients with structural damage progression.

Markov properties of cluster processes

We show that a Poisson cluster point process is a nearest-neighbour Markov point process [2] if the clusters have uniformly bounded diameter. It is typically not a finite-range Markov point process in the sense of Ripley and Kelly [12]. Furthermore, when the parent Poisson process is replaced by a Markov or nearest-neighbour Markov point process, the resulting cluster process is also nearest-neighbour Markov, provided all clusters are non-empty. In particular, the nearest-neighbour Markov property is preserved when points of the process are independently randomly translated, but not when they are randomly thinned.

Random tessellations in ℝd

This paper presents a general theory of random tessellations (i.e. stochastic aggregates of disjoint and space-filling cells) ind-dimensional Euclidean space. Some particular models of random tessellations are discussed in detail.

Detection and spatial characterization of minicolumnarity in the human cerebral cortex

BACKGROUND

Spatial characterization of vertical organization of neurons in human cerebral cortex, cortical columnarity or minicolumns, and its possible association with various psychiatric and neurological diseases has been investigated for many years.

NEW METHOD

In this study, we obtained 3D coordinates of disector sampled cells from layer III of Brodmann area 4 of the human cerebral cortex using light microscopy and 140-μm-thick glycolmethacrylate sections. A new analytical tool called cylindrical K-function was applied for spatial point pattern analysis of 3D datasets to see whether there is a spatially organized columnar structure. In order to demonstrate the behaviour of the cylindrical K-function, the result from brain tissues was compared with two models: A homogeneous Poisson process exhibiting complete spatial randomness, and a Poisson line cluster point process. The latter is a point process model in 3D space, which exhibits spatial structure of points similar to minicolumns.

RESULTS

The data show in three out of four samples nonrandom patterns in the 3D neuronal positions with the direction of minicolumns perpendicular to the pial surface of the brain - without a priori assuming the existence of minicolumns.

COMPARISON WITH EXISTING METHODS

Studies on columnarity are difficult and have mainly been based on two-dimensional images analysis of thin sections of the cerebral cortex with the a priori assumption that minicolumns existed.

CONCLUSIONS

A clear difference from complete spatial randomness in the data could be detected with the new tool, the cylindrical K-function, although classical functional summary statistics are less useful in this connection.

National surveillance of fungemia in Denmark (2004 to 2009)

A 6-year nationwide study of fungemia in Denmark was performed using data from an active fungemia surveillance program and from laboratory information systems in nonparticipating regions. A total of 2,820 episodes of fungemia were recorded. The incidence increased from 2004 to 2007 (7.7 to 9.6/100,000) and decreased slightly from 2008 to 2009 (8.7 to 8.6/100,000). The highest incidences were seen at the extremes of age (i.e., 11.3 and 37.1/100,000 for those <1 and 70 to 79 years old, respectively). The rate was higher for males than for females (10.1 versus 7.6/100,000, P = 0.003), with the largest difference observed for patients >50 years of age. The species distribution varied significantly by both age and gender. Candida species accounted for 98% of the pathogens, and C. albicans was predominant, although the proportion decreased (64.4% to 53.2%, P < 0.0001). C. glabrata ranked second, and the proportion increased (16.5% to 25.9%, P = 0.003). C. glabrata was more common in adults and females than in children and males, whereas C. tropicalis was more common in males (P = 0.020). C. krusei was a rare isolate (4.1%) except at one university hospital. Acquired resistance to amphotericin and echinocandins was rare. However, resistance to fluconazole (MIC of >4 μg/ml) occurred in C. albicans (7/1,183 [0.6%]), C. dubliniensis (2/65 [3.1%]), C. parapsilosis (5/83 [6.0%]), and C. tropicalis (7/104 [6.7%]). Overall, 70.8% of fungemia isolates were fully fluconazole susceptible, but the proportion decreased (79.7% to 68.9%, P = 0.02). The study confirmed an incidence rate of fungemia in Denmark three times higher than those in other Nordic countries and identified marked differences related to age and gender. Decreased susceptibility to fluconazole was frequent and increasing.

Mortality following acute medical admission in Denmark: a feasibility study

BACKGROUND

As the population ages, an increasing number of acute medical patients will be older and have comorbidities that may interact with their primary admission condition and worsen their prognosis.

OBJECTIVES

To examine whether 6-month mortality following acute medical admission was associated with gender, age, or comorbidity.

METHODS

We used the Danish National Patient Registry, covering all Danish hospitals, to identify all acute medical admissions to Aarhus University Hospital during 2008 and comorbidities. We obtained mortality data from the Danish Civil Registration System. We computed mortality risks and hazard ratios with 95% confidence intervals (CIs) for gender, age, and comorbidity groups.

RESULTS

We identified 3,727 patients (53.6% women) with a median age of 63 years for women and 60 years for men. The overall 6-month mortality rate was 12.8%. The adjusted hazard ratio was 2.77 (95% CI, 2.11-3.64) for patients aged 65-80 years and 5.25 (95% CI, 4.06-6.80) for patients older than 80 years, compared with patients younger than 65 years. The adjusted hazard ratio was 2.43 (95% CI, 1.82-3.24) and 3.87 (95% CI, 2.91-5.15) for patients with moderate and high comorbidity, respectively, compared with low comorbidity.

CONCLUSION

Age and comorbidity were important predictors of mortality after acute medical admission.

Waste collection systems for recyclables: an environmental and economic assessment for the municipality of Aarhus (Denmark)

Recycling of paper and glass from household waste is an integrated part of waste management in Denmark, however, increased recycling is a legislative target. The questions are: how much more can the recycling rate be increased through improvements of collection schemes when organisational and technical limitations are respected, and what will the environmental and economic consequences be? This was investigated in a case study of a municipal waste management system. Five scenarios with alternative collection systems for recyclables (paper, glass, metal and plastic packaging) were assessed by means of a life cycle assessment and an assessment of the municipality's costs. Kerbside collection would provide the highest recycling rate, 31% compared to 25% in the baseline scenario, but bring schemes with drop-off containers would also be a reasonable solution. Collection of recyclables at recycling centres was not recommendable because the recycling rate would decrease to 20%. In general, the results showed that enhancing recycling and avoiding incineration was recommendable because the environmental performance was improved in several impact categories. The municipal costs for collection and treatment of waste were reduced with increasing recycling, mainly because the high cost for incineration was avoided. However, solutions for mitigation of air pollution caused by increased collection and transport should be sought.

The commutability of external quality assurance serum and reference serum materials between the VITROS® Albumin Slide and four other routine albumin methods

Background

Between-method differences in external quality assurance schemes (EQAS) are assumed to be indicative of between-method differences in results for fresh diagnostic serum samples. However, this assumption is only valid if the EQAS fluid is shown to be commutable between methods with the fresh human samples. Using fresh human serum samples, we studied the commutability of six UK National EQAS (UKNEQAS) samples and two reference serum preparations using five methods for the measurement of albumin.

Methods

The VITROS® Albumin Slide was compared with two liquid reagent bromocresol green-based methods and two immunoturbidimetric methods. Thirty fresh human serum samples, six UKNEQAS samples and two reference materials were analysed over a period of five days by all methods. The reference materials were: a certified protein reference material, CRM470 (protein reference preparation) and the Scandinavian NFKK Reference Serum X.

Results

A concentration-dependent tendency towards non-commutability was seen for the six UKNEQAS samples. Two of the methods recovered the CRM470 above the upper limit of the expected range and the remaining three were within the expected range.

Conclusions

Assessment of commutability is important in the investigation of between-method differences in EQAS. External quality assurance and reference materials should have been demonstrated to be commutable and be available at multiple concentrations, before they may be considered appropriate for the assessment of accuracy.

Microbiological assessments of compost toilets: in situ measurements and laboratory studies on the survival of fecal microbial indicators using sentinel chambers

Compost toilet systems were assessed for their ability to reduce microbial indicators and pathogens. Bacterial pathogens were not detected in any samples indicating a low survival rate in composting feces and/or an initial low occurrence. Indicator bacteria showed large variations with no clear trend of lower bacterial numbers after longer storage. In controlled composting experiments, thermophilic conditions were only reached when amendments were made (grass and a sugar solution). Even then it was impossible to ensure a homogenous temperature in the composting fecal material and therefore difficult to achieve a uniform reduction and killing of indicator organisms. Presumptive thermotolerant coliforms, Salmonella typhimurium Phage 28 B and eggs of Ascaridia galli, proved useful as indicators. However, regrowth was detected for enterococci and total numbers of bacteria grown at 36 degrees C. These indicator parameters may therefore overestimate the level of other (pathogenic) bacteria present in the material and can not be recommended for use as reliable indicator organisms in composting toilet systems. The addition of indicator bacteria to fecal material contained in semi-permeable capsules proved to be a useful technique to ensure that microorganisms were contained in a small test volume.

Detection of MTRR 66A-->G polymorphism using the real-time polymerase chain reaction machine LightCycler for determination of composition of allele after restriction cleavage

The MTRR gene codes for methionine synthase reductase, one of the enzymes involved in the conversion of homocysteine to methionine. This conversion influences the overall level of total plasma homocysteine (tHcy) and mutations, which reduces the enzyme activity and results in an increased concentration of tHcy. A high homocysteine level is a well-documented independent risk factor for cardiovascular disease. A polymorphism in the gene for methionine synthase reductase (MTRR 66 A>G) has been shown to be associated with the risk of giving birth to a child with Down's syndrome, and the risk of having a foetus with neural tube defects. We have established a method for analysing MTRR 66A>G on DNA from dried blood spots using melting temperature analysis. The DNA was extracted from dried blood spots using a fast procedure by boiling only.

A longitudinal study of serum cobalamins and its binding proteins in lactating women

OBJECTIVE

To examine longitudinal changes in serum cobalamins, transcobalamin (TC) and haptocorrin (HC) during lactation and to investigate the influence of vitamin B12 supplementation on these parameters.

DESIGN

A 9-month follow-up study.

SUBJECTS AND METHODS

Lactating mothers (N=89) including 23 supplemented with vitamin B12 (1-18 microg/daily), 41 partly supplemented and 25 not supplemented. Blood samples collected 3 weeks (baseline) and 4 and 9 months post-partum were analysed for cobalamins, TC and HC. Both the total concentration and the cobalamin-saturated form (holo) of TC and HC were analysed.

RESULTS

No significant differences were observed in serum cobalamins or its binding proteins related to supplementation with vitamin B12 or the duration of lactation. Serum cobalamins remained unchanged from 3 weeks to 9 months post-partum. Total TC (holoTC) (median+/-s.e. pmol/l) decreased between 3 weeks (710+/-23 (85+/-12)) and 9 months (602+/-21 (76+/-11)) (P<0.0001 (P=0.0002)), whereas total HC (holoHC) increased from (422+/-11 (300+/-9)) at 4 months to (455+/-13 (317+/-10)) to 9 months post-partum (P<0.0001 (P<0.0001)).

CONCLUSION

We report a decrease in TC and an increase in HC during a 9-month period post-partum. No differences were observed between the vitamin B12-supplemented and the unsupplemented groups. Thus, supplementation with vitamin B12 has no impact on the circulating level of serum cobalamins or its binding proteins in a Danish population of lactating mothers.

Folate and vitamin B12 in relation to lactation: a 9-month postpartum follow-up study

OBJECTIVE

To investigate the relation between lactation and markers of folate and vitamin B12 (B12) deficiency in women with and without vitamin supplementation.

DESIGN

A 9-month follow-up study.

SUBJECTS AND METHODS

Blood samples from 91 women, who gave birth to a single healthy child, were collected 3 weeks, 4 and 9 months postpartum and analysed for circulating level of homocysteine (tHcy), methylmalonic acid (MMA), folate and B12. The participants were categorized as exclusively, partly or not breast-feeding dependent on the degree of lactation 4 months postpartum. During follow-up, lifestyle factors were recorded by structured interviews.

RESULTS

Among 72 exclusively breast-feeding women, the median (10-90% percentile) tHcy was 5.8 (3.1-8.3) micromol/l 3 weeks postpartum, 6.1 (4.1-10.3) micromol/l 4 months postpartum and 5.3 (3.6-8.7) micromol/I 9 months postpartum. At 9 months postpartum, none of the women breast-fed exclusively. No significant change occurred in the concentration of B12 and folate. Exclusively breast-feeding women without vitamin supplementation had higher median tHcy than supplemented exclusively breast-feeding women 4 and 9 months postpartum (7.0 vs 5.4 micromol/l (P < 0.001) and 5.8 vs 4.5 micromol/l (P = 0.003), respectively). Six women had increased (>15 micromol/l) tHcy; four of these were unsupplemented and exclusively breast-feeding.

CONCLUSION

We found no overall indication of depletion of the folate and B12 stores during the lactation period in this population. However, folate-supplemented women had lower tHcy and higher folate levels, suggesting a beneficial effect of supplementation with folate throughout lactation.

Piperacillin-resistant Escherichia coli bacteraemia: relation to empiric therapy and clinical outcome

Escherichia coli is a leading cause of bacteraemia. The aim of this study was to evaluate all E. coli positive blood cultures collected during a 4-y period in a haematological department using piperacillin plus netilmicin for empiric treatment of febrile episodes. We measured the incidence of piperacillin-resistant E. coli bacteraemia among haematological and non-haematological patients, described the importance of previous antibiotic treatment for resistance development in E. coli and evaluated the impact of piperacillin resistance on the clinical outcome of E. coli bacteraemia. 114 episodes of E. coli bacteraemia in 104 patients were recorded and 98 episodes in 88 patients (42 males and 46 females) with a median age of 64 y (range 19-85 y) were evaluated. In 81.6% of the episodes the patients had a haematological disorder, dominated by acute leukaemia (41.3%), chronic leukaemia (16.3%) and lymphoma (10%). The proportion of piperacillin-resistant E. coli was higher among haematological patients than non-haematological patients (25% vs 0%, p=0.02) and resistance was associated with piperacillin therapy during the previous month (p=0.05). No difference in clinical outcome was found between haematological patients infected with piperacillin-susceptible or -resistant E. coli (intensive care 12% vs 15%; mortality 22% vs 25%).

Inhaled nitric oxide therapy in neonates and children: reaching a European consensus

Inhaled nitric oxide (iNO) was first used in neonatal practice in 1992 and has subsequently been used extensively in the management of neonates and children with cardiorespiratory failure. This paper assesses evidence for the use of iNO in this population as presented to a consensus meeting jointly organised by the European Society of Paediatric and Neonatal Intensive Care, the European Society of Paediatric Research and the European Society of Neonatology. Consensus Guidelines on the Use of iNO in Neonates and Children were produced following discussion of the evidence at the consensus meeting.

Exercise, hormones, and body temperature. regulation and action of GH during exercise

That physical exercise stimulates pituitary GH secretion has been known for forty years, but the underlying mechanisms as well as the physiological significance remain elusive. We have previously shown that the concomitant increase in core temperature is essential for the exercise-induced GH release, inasmuch as exercise performed at 4 C results in a suppression of GH secretion, whereas passive heating constitutes a potent stimulus for GH release. Moreover, studies in normal subjects show that GH stimulates sweat production and evaporative heat loss during heat exposure with and without exercise, whereas GH-deficiency is associated with reduced sweat secretion and increased heat storage during similar conditions. The neurotransmitters involved in GH secretion during exercise remain uncertain; we therefore investigated the putative role of ghrelin, which is a gut-derived endogenous ligand for the GHS receptor. We measured circulating ghrelin levels before during and after submaximal aerobic exercise in healthy subjects and GH-deficient patients. The circulating ghrelin levels were unchanged during and after exercise in all subjects. Growth hormone stimulates lipolysis and lipid oxidation during basal and fasting conditions and we recently investigated whether GH also regulates substrate metabolism during exercise. The design involved GH-deficient patients studied during exercise with and without GH administration as compared to untreated healthy subjects. Growth hormone predominantly stimulated the turnover of free fatty acids in the recovery phase after exercise.

CONCLUSIONS

1) the increase in GH release during exercise is associated with the concomitant increase in body temperature, 2) GH stimulates sweat secretion and heat evaporation during exercise, which seems to be of distinct physiological significance, 3) ghrelin is not involved in exercise-induced GH release, 4) the impact of GH on substrate metabolism during exercise includes increased FFA turnover.

Evaluation of the DPC IMMULITE 2000 assay for total homocysteine in plasma

The present report describes an evaluation in three laboratories of the completely automated total homocysteine immunoassay adapted to the IMMULITE 2000 from DPC. The precision depended on the control materials used, but with quality control materials and patient samples imprecisions were found to be in the range of 5.3 to 6.1% and 5.4 to 6.0%, respectively. Dilution experiments proved the assay to be linear and correlations with HPLC and GC-MS methods were close (r=0.98 and 0.97, respectively). In addition, the samples from the Nordic program for external quality assessment of methylmalonic acid and homocysteine for 2000 were assayed in the three laboratories. Imprecision evaluated from these samples was 5.3% and the recovery of the added L-homocystine was equivalent to the mean recovery of the 58 participants in the program. The precision is close to the quality goals. In conclusion, the method is an attractive alternative when coping with an increasing number of requests for the analysis of total homocysteine.

Remifentanil vs. alfentanil for direct laryngoscopy: a randomized study comparing two total intravenous anaesthesia techniques. TIVA for direct laryngoscopy

The ideal anaesthesia for direct laryngoscopy is profound and yet brief. The present study sought to determine whether a new anaesthetic technique based on infusion of the ultra short-acting opioid remifentanil was superior to our routine alfentanil multiple-dose technique in terms of haemodynamic stability, stress responses and recovery. A total of 58 patients were randomized to receive propofol and either remifentanil or alfentanil as part of a total intravenous anaesthesia. In the remifentanil group, systolic blood pressure during anaesthesia remained significantly lower than baseline values, while it increased significantly in the alfentanil group. None of the patients receiving remifentanil showed stress responses (hypertension, tachycardia, somatic or autonomic responses), compared to 22 patients (79%) in the alfentanil group (P < 0.0001). In the remifentanil group, hypotension or bradycardia requiring intervention arose in 5 (18%) and 3 patients (11%); neither response was seen in the alfentanil group. The period from the end of propofol infusion until extubation was 5 min longer in the remifentanil group (P < 0.0001), whereas the time from extubation until discharge was similar in the two groups. Thus, neither technique showed sufficient haemodynamic stability, and further studies are needed to determine optimal dosages of propofol and opioid.

Platelet activity and in vivo arterial thrombus formation in rats with mild hyperhomocysteinaemia

Elevated plasma levels of total homocysteine (hcy) have been associated with an increased occurrence of arterial thrombosis. In the present study, we investigated the influence of hyperhomocysteinaemia on platelet aggregation and arterial thrombus formation in vivo. Fifty-one rats were included in the study, of which 29 received hcy in the drinking water for 4 weeks. Blood samples were withdrawn for measurement of platelet count and mean platelet volume. Platelet aggregation response in platelet-rich plasma following adenosine diphosphate or collagen stimulation were examined. In vivo thrombus formation was investigated by transillumination and videotape recording of the rat femoral artery after a thrombogenic injury was established. Off-line videotape analysis using computer-assisted planimetry permitted quantification of the thrombus area, and area versus time curves were obtained. In the intervention group receiving hcy, total hcy in plasma increased two-fold to 14.3 micromol/l, as compared with 7.3 micromol/l in the control group (P < 0.001). The platelet count and mean platelet volume did not differ between the two groups. In vivo thrombus formation expressed as the area under the curve or maximum thrombus area was not found to be altered in the presence of an increased homocysteine level, neither was adenosine diphosphate-induced platelet aggregation. However, collagen-induced platelet aggregation significantly decreased in the hcy group (P = 0.02). Pro-thrombotic effects of isolated mild hyperhomocysteinaemia are not supported by the present study in rats.

Homocysteine and atherothrombosis

Atherosclerosis with or without thrombosis superimposed is the most frequent cause of ischemic heart disease (IHD), peripheral arterial disease, and a main cause of stroke. Conflicting results have been reported in genetic, observational, and experimental studies on the relationship between homocysteine and these atherothrombotic diseases. Although cardiovascular complications are common in homocystinuric patients (severe hyperhomocysteinemia), IHD, the most frequent manifestation of atherothrombosis in the general population, appears to be rare. On the basis of findings in individuals with hyperhomocysteinemia of genetic origin, there is in fact no clear evidence for a causal role of homocysteine in the pathogenesis of atherothrombotic disease, and the positive association between plasma homocysteine and IHD observed in many, but not all epidemiologic studies does not prove causality. To infer causality from observational studies, there should be a temporal, consistent, strong, independent, graded (dose-response effect), and duration-dependent relationship between exposure and outcomes, and a biologically plausible mechanism should exist. The relationship between plasma homocysteine levels and IHD does not fulfill these criteria beyond reasonable doubt. In the general population, plasma homocysteine levels are to a great extent determined by dietary habits, and plasma homocysteine could be a marker, or a consequence, of atherothrombosis and/or risk-associated behavior (e.g., a diet low in fruits and vegetables) rather than a cause of atherothrombosis. Experimentally, hyperhomocysteinemia is not in itself atherogenic in normal animals with relatively low plasma cholesterol levels. The homocysteine theory of atherosclerosis should be tested more thoroughly in hypercholesterolemic animals that develop atherosclerosis spontaneously to determine whether elevated plasma homocysteine levels are harmful under atherogenic conditions. A causal role of homocysteine in atherothrombotic disease remains to be established.

Effects of growth hormone on renal tubular handling of sodium in healthy humans

To investigate the mechanisms behind the water- and sodium-retaining effects of growth hormone (GH), we studied the effect of GH on 1) water and sodium homeostasis, 2) the renin-angiotensin-aldosterone system (RAAS), and 3) lithium clearance (C(Li)) with and without concomitant prostaglandin (PG) synthesis inhibition with ibuprofen. GH administration for 6 days induced a significant increase in plasma renin, which was abolished by coadministration of ibuprofen (mU x l(-1) x 24 h(-1): control: 22.4 +/- 4.3; GH: 37.7 +/- 8.8; ibuprofen: 15.2 +/- 3.0; GH + ibuprofen: 19.7 +/- 2.5; ANOVA: P < 0.01). Comparable increments in extracellular volume were seen after 6-day treatment with GH alone and in combination with ibuprofen [liters: control, 19.57 +/- 0.92; GH, 20.80 +/- 1.00 (ANOVA: P < 0.0005); ibuprofen, 19.38 +/- 0.90; GH + ibuprofen, 21.63 +/- 1.37 (ANOVA: P < 0.0005)]. Treatment with GH increased C(Li) and changed the tubular handling of sodium and water. The absolute distal sodium reabsorption was increased, and this was only partially counterbalanced by decreased reabsorption in the proximal tubules. The data demonstrate that GH-induced activation of the RAAS can be blocked by concomitant PG synthesis inhibition and that the tubular effects of GH include increased distal nephron sodium and water reabsorption.

Airway management behaviour, experience and knowledge among Danish anaesthesiologists--room for improvement

BACKGROUND

Problems with managing the airways in relation to anaesthesia causes severe morbidity and mortality. A large proportion of these adverse respiratory events is preventable. Still patients continue to die from airway disasters related to anaesthesia, also in Scandinavia. The goal of this study is to identify which efforts are likely to improve this situation.

METHODS

A questionnaire asking about experience, behaviour and availability of various items of equipment was mailed to all members of the Danish Society of Anaesthesiologists and were returned anonymously.

RESULTS

More than 65% of respondents have sufficient access to a flexible fibrescope, but still 17% of specialists have no access and the vast majority (>67%) has little (1-10 times) or no experience in its use for awake intubation. A total of 52-70% knew the basic principles of the ASA difficult airway algorithm, but despite this only 25-50% would perform awake intubation if a difficult intubation was expected. More than 20% of respondents had experienced preventable airway management mishaps. In all, 18-46% did not know how to oxygenate via the cricothyroid membrane.

CONCLUSION

There is room for improvement regarding airway management skills among Danish anaesthesiologists. It is likely that airway management can be improved by: A) Better knowledge of an appropriate plan, algorithm, for airway management. B) Awake intubation used more often. C) More experience in fibreoptic intubation. D) All anaesthesiologists accepting that previous difficult intubation is an indicator of future difficulties. E) All anaesthesiologists knowing, and practising on manikins, how to oxygenate via the cricothyroid membrane. F) Always having a laryngeal mask airway immediately available when inducing anaesthesia.

Dietary supplementation with methionine and homocysteine promotes early atherosclerosis but not plaque rupture in ApoE-deficient mice

Hyperhomocysteinemia is an independent risk factor for atherothrombosis. However, causality is unproven, and it remains unknown whether hyperhomocysteinemia promotes atherosclerosis, plaque rupture, and/or thrombosis. We evaluated the short- and long-term effects of hyperhomocysteinemia on plaque size and structure in 99 atherosclerosis-prone apolipoprotein E-deficient mice. Hyperhomocysteinemia was induced by methionine (Met) or homocysteine (HcyH) supplementation: low Met (+11 g Met/kg food), high Met (+33 g Met/kg food), low HcyH (0.9 g HcyH/L drinking water), and high HcyH (1.8 g HcyH/L drinking water). Met and HcyH supplementation significantly raised plasma total homocysteine levels by 4- to 16-fold above those observed in mice fed a control diet (up to 146.1 micromol/L). Compared with controls, aortic root plaque size was significantly larger in supplemented groups after 3 months (56% and 173% larger in high-Met and high-HcyH, respectively) but not after 12 months. Hyperhomocysteinemia was associated with an increase in the amount of collagen in plaques after both 3 and 12 months. Mechanical testing of the tail tendons revealed no weakening of collagen after 12 months of hyperhomocysteinemia. Many plaques in both control and supplemented mice appeared rupture prone morphologically, but all aortic root plaques and all but 1 coronary plaque had an intact surface without rupture or thrombosis. Thus, diet-induced hyperhomocysteinemia promotes early atherosclerosis and plaque fibrosis but does not, even in the long term, weaken collagen or induce plaque rupture.

The occurrence of sinusitis in HIV-infected patients with fever

Sinusitis is commonly occurring in patients infected with Human Immunodeficiency Virus I (HIV), but the occurrence and etiology have not been established. The purpose of this study was prospectively to determine the occurrence, site and type of paranasal sinus abnormalities seen on MRI in HIV-infected patients with fever, to relate the abnormalities to clinical and immunological parameters, and to determine the microbiological agents found in the sinus aspirates. MRI was performed in 54 HIV-infected patients with 70 evaluable episodes of fever. Patients receiving antibiotics were excluded. Bactrim was permitted, when given as prophylaxis of Pneumocystis carinii pneumonia. If abnormalities were found on MRI, sinus aspiration was performed and the aspirate investigated. MRI abnormalities were found in 54.3% of the patients with a significantly higher occurrence of pathological changes in AIDS patients compared with HIV-infected without AIDS. In approximately 2/3 of the aspirates a probable, etiologic agent was found. However, 1/3 of these agents were atypical such as cytomegalovirus and mycobacteriae; in one patient Non-Hodgkin's lymphoma was found. The high occurrence of sinusitis in HIV-infected patients and the atypical findings in the sinus aspirates stress the importance of searching for sinusitis and the etiology to ensure the correct treatment.