The Effect of beta-blockade on objectively measured physical fitness in patients with abdominal aortic aneurysms--A blinded interventional study

BACKGROUND

Perioperative beta-blockade is widely used, especially before vascular surgery; however, its impact on exercise performance assessed using cardiopulmonary exercise testing (CPET) in this group is unknown. We hypothesized that beta-blocker therapy would significantly improve CPET-derived physical fitness in this group.

METHODS

We recruited patients with abdominal aortic aneurysms (AAA) of <5.5 cm under surveillance. All patients underwent CPET on and off beta-blockers. Patients routinely prescribed beta-blockers underwent a first CPET on medication. Beta-blockers were stopped for one week before a second CPET. Patients not routinely taking beta-blockers underwent the first CPET off treatment, then performed a second CPET after commencement of bisoprolol for at least 48 h. Oxygen uptake (.VO2) at estimated lactate threshold and .VO2 at peak were primary outcome variables. A linear mixed-effects model was fitted to investigate any difference in adjusted CPET variables on and off beta-blockers.

RESULTS

Forty-eight patients completed the study. No difference was observed in .VO2 at estimated lactate threshold and .VO2 at peak; however, a significant decrease in .VE/.VCO2 at estimated lactate threshold and peak, an increase in workload at estimated lactate threshold., O2 pulse and heart rate both at estimated lactate threshold and peak was found with beta-blockers. Patients taking beta-blockers routinely (chronic group) had worse exercise performance (lower .VO2 ).

CONCLUSIONS

Beta blockade has a significant impact on CPET-derived exercise performance, albeit without changing .VO2 at estimated lactate threshold and.VO2 at peak. This supports performance of preoperative CPET on or off beta-blockers depending on local perioperative practice.

CLINICAL TRIAL REGISTRATION

NCT 02106286.

Septic arthritis in males with haemophilia

We used data collected as part of the Universal Data Collection (UDC) surveillance project in haemophilia treatment centers (HTC) to study the incidence, risk factors and impact of septic arthritis among males with haemophilia. Patients participating in UDC on two or more occasions were included. Cases were defined as patients with documented joint infection. Characteristics of the cases were compared with those of haemophilia patients without infection. Among the 8026 eligible patients with 36 015 person-years of follow-up, 30 (0.37%) had a documented joint infection (incidence rate 83 per 100 000 person-years). In a logistic regression model, only increasing age (OR = 6.1 for age > or =30), race/ethnicity other than white (OR = 3.9), presence of inhibitor (OR = 3.9), invasive procedure in the past year (OR = 2.7) and presence of one or more target joints (OR = 3.2) remained statistically significant. Central venous access devices use and hepatitis C virus and HIV infection were not associated with septic arthritis risk after adjusting for potential confounders. Study limitations include possible underestimation of septic arthritis rate in this population and its retrospective design. We conclude that septic arthritis is an uncommon complication of haemophilia occurring primarily in joints most affected by bleeding and reparative surgical interventions.

Expiratory flow limitation detected by forced oscillation and negative expiratory pressure

The within-breath change in reactance (Delta(rs)) measured by forced oscillation technique (FOT) at 5 Hz reliably detects expiratory flow limitation in chronic obstructive pulmonary disease (COPD). The present study compared this approach to the standard negative expiratory pressure (NEP) method. In total, 21 COPD patients were studied by applying both techniques to the same breath and in 15 patients the measurements were repeated after bronchodilator. For each patient and condition five NEP tests were performed and independently scored by three operators unaware of the FOT results. In 180 tests, FOT classified 53.3% as flow limited. On average, the operators scored 27.6% of tests flow limited and 47.6% non-flow limited, but could not score 24.8%. The methods disagreed in 7.9% of cases; in 78% of these the NEP scores differed between operators. Bronchodilation reduced NEP and DeltaX(rs) scores, with only the latter achieving significance. Averaging the operators' NEP scores, a threshold between 24.6-30.8% of tidal volume being flow limited by NEP produced 94% agreement between methods. In conclusion, when negative expiratory pressure and forced oscillation technique were both available they showed good agreement. As forced oscillation technique is automatic and can measure multiple breaths over long periods, it is suitable for monitoring expiratory flow limitation continuously and identifying patients' breathing close to the onset of expiratory flow limitation, where intermittent sampling may be unrepresentative.

Intravenous aminophylline in patients admitted to hospital with non-acidotic exacerbations of chronic obstructive pulmonary disease: a prospective randomised controlled trial

BACKGROUND

Intravenous aminophylline is commonly used in the treatment of exacerbations of chronic obstructive pulmonary disease (COPD), despite limited evidence for its efficacy and known risks of toxicity. We hypothesised that adding intravenous aminophylline to conventional treatment would not produce clinically important changes in the speed of spirometric or symptomatic recovery or shorten hospital stay in patients with exacerbations of COPD.

METHODS

Eighty patients admitted to hospital with non-acidotic exacerbations of COPD were recruited at admission to a randomised, double blind, placebo controlled study comparing intravenous aminophylline 0.5 mg/kg/hour after an appropriate loading dose with an equivalent volume of 0.9% saline. The primary outcome was the change in post-bronchodilator forced expiratory volume in 1 second (FEV(1)) over the first 5 days of the admission. Secondary end points were changes in self-reported breathlessness, arterial blood gas tensions, forced vital capacity (FVC), and length of hospital stay.

RESULTS

There was no difference in the post-bronchodilator FEV(1) over the first 5 days between the aminophylline and placebo groups. In the aminophylline group, 2 hours of treatment produced a small but significant rise in arterial pH (p = 0.001) and a fall in arterial carbon dioxide tension (p = 0.01) compared with placebo treatment. There were no differences in the severity of breathlessness, post-bronchodilator FVC, or length of hospital stay between the groups. Nausea was a more frequent side effect in the aminophylline group (46% v 22%; p<0.05), but palpitations and headache were noted equally in both groups.

CONCLUSIONS

Although intravenous aminophylline produced small improvements in acid-base balance, these did not influence the subsequent clinical course. No evidence was found for any clinically important additional effect of aminophylline treatment when used with high dose nebulised bronchodilators and oral corticosteroids. Given its known toxicity, we cannot therefore recommend the use of intravenous aminophylline in the treatment of non-acidotic COPD exacerbations.

Acute absorption of folic acid from a fortified low-fat spread

OBJECTIVE

To explore the feasibility of low-fat spreads as vehicles for folic acid (FA) fortification by determining the acute absorption of FA from a fortified spread.

DESIGN

Double blind, crossover study to test each of the following treatments administered at 1-weekly intervals: (A) 20 g low-fat (40%) spread fortified with 200 microg FA and a placebo tablet; (B) 20 g low-fat placebo spread and a 200 microg FA tablet; (C) 20 g low-fat placebo spread and a placebo tablet.

SUBJECTS

A total of 13 male volunteers, aged 31.8+/-13.2 y.

MAIN OUTCOME MEASURES

Plasma total folate concentrations, measured before and up to 10 h after each treatment (n=10 samples per treatment).

RESULTS

Plasma folate concentrations were significantly increased compared with baseline values 1 h after administration of the FA tablet, and 1.5 h after the FA spread, and remained significantly higher than the baseline values for up to 7 h after both treatments. The maximum plasma folate response (R(max)), corrected for baseline values and 'placebo response', was established between 1 and 3 h postprandially in response to both FA spread and FA tablet, and no significant difference in R(max) was found between the two treatments (13.4 vs 14.4 nmol/l, P=0.9). The acute absorption of FA from fortified spread relative to that from the tablet, calculated on the basis of area under the plasma folate response curve, was 67% (P=0.04).

CONCLUSION

The absorption of FA from fortified low-fat spread, although lower than from a tablet, is effective. These results suggest that low-fat spreads, typically associated with fat-soluble vitamin fortification, may also be considered feasible as vehicles for FA fortification.

Support vector machine classification and validation of cancer tissue samples using microarray expression data

MOTIVATION

DNA microarray experiments generating thousands of gene expression measurements, are being used to gather information from tissue and cell samples regarding gene expression differences that will be useful in diagnosing disease. We have developed a new method to analyse this kind of data using support vector machines (SVMs). This analysis consists of both classification of the tissue samples, and an exploration of the data for mis-labeled or questionable tissue results.

RESULTS

We demonstrate the method in detail on samples consisting of ovarian cancer tissues, normal ovarian tissues, and other normal tissues. The dataset consists of expression experiment results for 97,802 cDNAs for each tissue. As a result of computational analysis, a tissue sample is discovered and confirmed to be wrongly labeled. Upon correction of this mistake and the removal of an outlier, perfect classification of tissues is achieved, but not with high confidence. We identify and analyse a subset of genes from the ovarian dataset whose expression is highly differentiated between the types of tissues. To show robustness of the SVM method, two previously published datasets from other types of tissues or cells are analysed. The results are comparable to those previously obtained. We show that other machine learning methods also perform comparably to the SVM on many of those datasets.

AVAILABILITY

The SVM software is available at http://www.cs. columbia.edu/ approximately bgrundy/svm.

Construction and visualisation of three-dimensional facial statistics

This paper presents a new method for the construction of three-dimensional (3D) probabilistic facial averages and demonstrates the potential for applications in clinical craniofacial research and patient assessment. Averages are constructed from a database of registered laser-range scans and photographic images using feature based image warping. Facial features are extracted using a template of connected contours, adapted to each subject interactively using snakes. Each subject's images are warped to the average template shape and the mean depth, colour and covariance matrix is found at each point. Statistical comparison of individuals with an average or between two averages is visualised by converting the probabilities to a coloured texture map.

Comparative antibody response in harbour and grey seals naturally infected by a morbillivirus

The antibody response of free-ranging harbour and grey seals, naturally infected by a morbillivirus, was assessed using a virus neutralizing test and a radio-immunoprecipitation assay. The prevalence of antibody was similar between species, however, grey seals had significantly higher virus neutralizing titers. Serum from clinically healthy grey seals precipitated the nucleocapsid (N) protein along with the hemagglutinin (H) and fusion (F) glycoproteins. By contrast, significantly fewer harbour seal sera precipitated the envelope glycoproteins and responses were weaker than those of grey seals. One harbour seal with acute morbillivirus pneumonia, and two with encephalitis precipitated only the N protein. Serum from four harbour seals with encephalitis weakly recognized the envelope glycoproteins. Thus, the antibody response of grey seals appears more competent than that of harbour seals with respect to morbillivirus antigens. We speculate that this difference between the species may be an important determinant of morbillivirus susceptibility.

Epizootiology of morbillivirus infection in harp, hooded, and ringed seals from the Canadian Arctic and western Atlantic

Using a virus neutralization technique, we found phocine distemper virus (PDV) antibody in 130 (83% of 157) harp seals (Phoca groenlandica) from the western North Atlantic sampled between 1988 and 1993 inclusive. In contrast, only 44 (24% of 185) hooded seals (Cystophora cristata) had antibodies against PDV even though they were sympatric with harp seals and were sampled over a similar period, from 1989 to 1994 inclusive. Antibodies occurred in 106 (41%) of 259 ringed seals (Phoca hispida); this prevalence was higher than expected given the solitary behavior and territoriality characteristic of this species. Seropositive ringed seals were found at each of seven locations across Arctic Canada from Baffin Bay to Amundsen Gulf at which samples were collected between 1992 and 1994. However, the prevalence of infection was highest where ringed seals are sympatric with harp seals in the eastern Canadian Arctic.

Morbillivirus infection in cetaceans of the western Atlantic

We report serologic evidence of morbillivirus infection in eleven of fifteen species of odontocete cetaceans from the western Atlantic since 1986. Blood samples were obtained both from free-ranging and stranded animals. Virus neutralizing titers were higher against porpoise and dolphin morbilliviruses than against peste des petits ruminants virus, phocine distemper virus or canine distemper virus (CDV). Serum from five species, tested in a heterologous immunoprecipitation assay using radiolabelled CDV, precipitated the nucleocapsid (N) protein. Clinical morbillivirus infection may potentially impact already threatened species such as the harbour porpoise and precipitate mass strandings of socially cohesive odontocetes.

Planning nursing education for the 21st century

In looking towards the 21st century, the faculty at the Presbyterian Hospital School of Nursing, along with the Presbyterian Health Services Corporation and Queen's College, adopted a 1-2-1 programme. The process of developing a new nursing curriculum is presented as the task force proceeded from the philosophy and goals to conceptual framework and curriculum objectives. After discussions with nurse administrators and educators, extensive literature reviews and brainstorming sessions, concepts and subconcepts were chosen to form a philosophy. The metaparadigm of nursing and other related concepts were then organized into a conceptual framework. Ongoing communication and feedback from the faculty ensured group ownership of all documents. The eclectic organizational scheme was a good fit for a large faculty with differing beliefs and values about a nursing curriculum. The process of developing a future orientated nursing curriculum has been exciting, challenging and rewarding. The faculty is committed to the new philosophy, goals and conceptual framework and believe that the 1-2-1 programme will educate future practitioners who are prepared to meet the challenges and changes in health care for the 21st century.

A 33-year-old woman with a propranolol and chlorpromazine overdose, with applied nursing diagnoses

The challenge of emergency nursing comes from opportunities to increase knowledge and integrate it into our clinical practice. We face the challenge of identifying pertinent nursing diagnoses for our patients and linking them with the interventions used in our patients' care. From this information we can verify effectiveness of care and increase nursing's scientific body of knowledge.

Correlation between humoral immune responses and presence of virus in the CNS in dogs experimentally infected with canine distemper virus

The role of the humoral immune response in clearance or prevention of canine distemper viral encephalitis of dogs infected with a virulent strain of canine distemper virus has been evaluated. Dogs that have demyelinating lesions, CDV proteins and infectious virus in their brains demonstrate an impaired humoral immune response. In dogs that recover from infection and contain no demyelinating lesions, viral proteins or infectious virus in the brain, antibodies to the internal proteins of CDV are observed early after infection. Later antibodies to primarily the H protein are detectable in sera of these dogs and the appearance of antibodies against the surface glycoprotein (H) correlates with the absence of lesions, CDV antigen and infectious virus in the brains of these dogs. Very late after infection immunoprecipitating antibody to all CDV antigens diminished rapidly so that at about ten weeks post infection antibodies that precipitate CDV antigens are barely detectable.

Humoral immune responses in seals infected by phocine distemper virus

Recently the isolation and characterisation of a morbillivirus which caused high mortality in common seals (Phoca vitulina) in 1988 have been reported. Because of the clinical and pathological similarity of the disease in seals to that of distemper in dogs, the name phocine distemper virus (PDV) has been proposed. There are marked differences in the virus-induced proteins of PDV compared to other morbilliviruses and the humoral immune response of moribund and dead seals to PDV was restricted to some of the internal antigens of PDV, similar to the response described earlier for canine distemper virus infection in dogs.