Genetic analysis of infectious pancreatic necrosis virus from Scotland

Infectious pancreatic necrosis (IPN) is a highly contagious disease of young salmonid fish, and is one of the most serious economic diseases in aquaculture. In Scotland, an increase in IPN virus (IPNV) outbreaks in seawater Atlantic salmon, Salmo salar, has been reported in recent years. The aim of this study was to analyse the VP2 gene from recent IPNV isolates from Scotland, to determine whether there are epidemiological links between IPNV isolates from farms (13), wild fish (17) and the environment (6) in order to investigate potential wild and farmed fish interactions. Comparison of the nucleotide sequence of the VP2 gene revealed that 34 of 36 isolates were 97.1-100% similar and the deduced amino acid sequences showed 97-100% identity. Two isolates from wild fish exhibited the most divergence at 85-87.3% similarity to the other isolates at the nucleotide level and 88.2-90.8% identity at the deduced amino acid level. Phylogenetic analyses revealed that 34 of 36 of the isolates from Scotland were genetically closely related to the A2 (Sp) serotype of IPNV. The two wild isolates from seatrout, Salmo trutta, and flounder, Platichthys flesus, were most closely related to the European A5 (Te) serotype. This study represents a comprehensive IPNV phylogenetic study that indicates that there are closely related or identical isolates in circulation in the marine environment, which adds evidence that disease interactions between wild and farmed fish may occur. This type of analysis is a useful tool in the management and control of fish diseases because it can assist in the identification of epidemiological links and highlight potential risks to aquaculture.

Detection of infectious pancreatic necrosis virus (IPNV) from the environment in the vicinity of IPNV-infected Atlantic salmon farms in Scotland

Infectious pancreatic necrosis virus (IPNV) has been isolated from mussels, sediment and surface water in the vicinity of clinically infected salmon farms, at shore bases supplying the farms and for several hundred metres distance from farms in the direction of current flow. There was evidence of decreasing prevalence of IPNV in mussels from Shetland once IPN outbreaks subsided, indicating they are an unlikely source of re-infection on farms. There was little evidence of persistence in the environment, although conclusions were complicated by the presence of IPNV on neighbouring farms 1 year after the outbreak.

The influence of postoperative coronal alignment on revision surgery in total knee arthroplasty

This study examines the association between postoperative coronal tibiofemoral alignment and revision surgery in knee arthroplasty. We retrospectively reviewed the case notes and post-operative long-leg radiographs of 197 Kinemax knee arthroplasty with mean follow-up of 9 years (SD 2.2). They were divided into three groups: neutral, valgus and varus. Revision or decision to revise was used as a hard endpoint. There was no statistical difference among the three groups (p=0.78). We conclude that aseptic failure of a total knee is multifactorial. Coronal tibio-femoral alignment may not be as important a cause of failure as has been previously thought.

Intellectual and adaptive behaviour functioning in pantothenate kinase-associated neurodegeneration

BACKGROUND

Pantothenate kinase-associated neurodegeneration (PKAN), an extremely rare autosomal recessive disorder resulting in iron accumulation in the brain, has a diverse phenotypic expression. Based on limited case studies of one or two patients, intellectual impairment is considered part of PKAN. Investigations of cognitive functioning have utilized specific neuropsychological tests, without attention to general intellectual skills or adaptive behaviour.

METHODS

Sixteen individuals with PKAN completed measures of global intellectual functioning, and participants or care providers completed measures of adaptive behaviour skills and day-to-day functional limitations. Clinicians provided global ratings of condition severity.

RESULTS

Testing with standardized measures documented varied phenotypic expression, with general cognitive skills and adaptive behaviour ranging from high average to well below average. Age of disease onset correlated with measures of intellectual functioning, adaptive functioning and disease severity.

CONCLUSIONS

Findings support previously described clinical impressions of varied cognitive impairment and the association between age of onset and impairment. Further, they add important information regarding the natural history of the disease and suggest assessment strategies for use in treatment trials.

Cognitive behavioural therapy in chronic fatigue syndrome: a randomised controlled trial of an outpatient group programme

OBJECTIVES

To test the hypothesis that group cognitive behavioural therapy (CBT) will produce an effective and cost-effective management strategy for patients in primary care with chronic fatigue syndrome/myalgic encephalopathy (CFS/ME).

DESIGN

A double-blind, randomised controlled trial was adopted with three arms. Outcomes were assessed at baseline and 6 and 12 months after first assessment and results were analysed on an intention-to-treat basis.

SETTING

A health psychology department for the management of chronic illness in a general hospital in Bristol, UK.

PARTICIPANTS

Adults with a diagnosis of CFS/ME referred by their GP.

INTERVENTIONS

The three interventions were group CBT incorporating graded activity scheduling, education and support group (EAS) and standard medical care (SMC).

OUTCOME MEASURES

The primary outcome measure was the Short Form with 36 Items (SF-36) physical and mental health summary scales. Other outcome measures included the Chalder fatigue scale, Hospital Anxiety and Depression Scale, General Health Questionnaire, physical function (shuttles walked, walking speed and perceived fatigue), health utilities index and cognitive function (mood, recall and reaction times).

RESULTS

A total of 153 patients were recruited to the trial and 52 were randomised to receive CBT, 50 to EAS and 51 to SMC. Twelve patients failed to attend for the 12-month follow-up and 19 patients attended one follow-up, but not both. The sample was found to be representative of the patient group and the characteristics of the three groups were similar at baseline. Three outcome measures, SF-36 mental health score, Chalder fatigue scale and walking speed, showed statistically significant differences between the groups. Patients in the CBT group had significantly higher mental health scores [difference +4.35, 95% confidence interval (CI) +0.72 to +7.97, p = 0.019], less fatigue (difference -2.61, 95% CI -4.92 to -0.30, p = 0.027) and were able to walk faster (difference +2.83 shuttles, 95% CI +1.12 to +5.53, p = 0.0013) than patients in the SMC group. CBT patients also walked faster and were less fatigued than those randomised to EAS (walking speed: difference +1.77, 95% CI +0.025 to +3.51, p = 0.047; fatigue: difference -3.16, 95% CI -5.59 to -0.74, p = 0.011). Overall, no other statistically significant difference across the groups was found, although for many measures a trend towards an improved outcome with CBT was seen. Except for walking speed, which, on average, increased by +0.87 shuttles (95% CI +0.09 to +1.65, p = 0.029) between the 6- and 12-month follow-ups, the scores were similar at 6 and 12 months. At baseline, 30% of patients had an SF-36 physical score within the normal range and 52% had an SF-36 mental health score in the normal range. At 12 months, the physical score was in the normal range for 46% of the CBT group, 26% of the EAS group and 44% of SMC patients. For mental health score the percentages were CBT 74%, EAS 67% and SMC 70%. Of the CBT group, 32% showed at least a 15% increase in physical function and 64% achieved a similar improvement in their mental health. For the EAS and SMC groups, this improvement in physical and mental health was achieved for 40 and 60% (EAS) and 49 and 53% (SMC), respectively. The cost-effectiveness of the intervention proved very difficult to assess and did not yield reliable conclusions.

CONCLUSIONS

Group CBT did not achieve the expected change in the primary outcome measure as a significant number did not achieve scores within the normal range post-intervention. The treatment did not return a significant number of subjects to within the normal range on this domain; however, significant improvements were evident in some areas. Group CBT was effective in treating symptoms of fatigue, mood and physical fitness in CFS/ME. It was found to be as effective as trials using individual therapy in these domains. However, it did not bring about improvement in cognitive function or quality of life. There was also evidence of improvement in the EAS group, which indicates that there is limited value in the non-specific effects of therapy. Further research is needed to develop better outcome measures, assessments of the broader costs of the illness and a clearer picture of the characteristics best fitted to this type of intervention.

Determination by liquid chromatography-mass spectrometry of clomiphene isomers in the plasma of patients undergoing treatment for the induction of ovulation

A rapid, sensitive and selective LC-MS method is described for the simultaneous determination of zuclomiphene and enclomiphene in plasma from patients undergoing treatment with clomiphene citrate for the induction of ovulation. Samples spiked with N-didesmethyltamoxifen, the internal standard, were extracted into methyl tertiary butyl ether. The compounds were separated on a Luna C(18) analytical column, and a mobile phase of methanol-water (70:30 v/v) containing 0.05% trifluoroacetic acid at a flow rate of 1ml/min. The limits of determination were 35pg/ml and 7pg/ml for zu- and enclomiphene, respectively. Within-day coefficients of variation ranged from 2.1% to 7.2%.

A small temperature rise may contribute towards the apparent induction by microwaves of heat-shock gene expression in the nematode Caenorhabditis Elegans

We have previously reported that low intensity microwave exposure (0.75-1.0 GHz CW at 0.5 W; SAR 4-40 mW/kg) can induce an apparently non-thermal heat-shock response in Caenorhabditis elegans worms carrying hsp16-1::reporter genes. Using matched copper TEM cells for both sham and exposed groups, we can detect only modest reporter induction in the latter exposed group (15-20% after 2.5 h at 26 degrees C, rising to approximately 50% after 20 h). Traceable calibration of our copper TEM cell by the National Physical Laboratory (NPL) reveals significant power loss within the cell (8.5% at 1.0 GHz), accompanied by slight heating of exposed samples (approximately 0.3 degrees C at 1.0 W). Thus, exposed samples are in fact slightly warmer (by < or =0.2 degrees C at 0.5 W) than sham controls. Following NPL recommendations, our TEM cell design was modified with the aim of reducing both power loss and consequent heating. In the modified silver-plated cell, power loss is only 1.5% at 1.0 GHz, and sample warming is reduced to approximately 0.15 degrees C at 1.0 W (i.e., < or =0.1 degrees C at 0.5 W). Under sham:sham conditions, there is no difference in reporter expression between the modified silver-plated TEM cell and an unmodified copper cell. However, worms exposed to microwaves (1.0 GHz and 0.5 W) in the silver-plated cell also show no detectable induction of reporter expression relative to sham controls in the copper cell. Thus, the 20% "microwave induction" observed using two copper cells may be caused by a small temperature difference between sham and exposed conditions. In worms incubated for 2.5 h at 26.0, 26.2, and 27.0 degrees C with no microwave field, there is a consistent and significant increase in reporter expression between 26.0 and 26.2 degrees C (by approximately 20% in each of the six independent runs), but paradoxically expression levels at 27.0 degrees C are similar to those seen at 26.0 degrees C. This surprising result is in line with other evidence pointing towards complex regulation of hsp16-1 gene expression across the sub-heat-shock range of 25-27.5 degrees C in C. elegans. We conclude that our original interpretation of a non-thermal effect of microwaves cannot be sustained; at least part of the explanation appears to be thermal.

An evaluation of current diagnostic tests for the detection of infectious salmon anaemia virus (ISAV) following experimental water-borne infection of Atlantic salmon, Salmo salar L

Four commonly used diagnostic tests [reverse transcription polymerase chain reaction (RT-PCR), indirect fluorescent antibody test (IFAT), virus culture and light microscopy] were evaluated for their ability to detect infectious salmon anaemia virus (ISAV) or tissue pathology following experimental infection of Atlantic salmon. Fish were infected with ISAV by water-borne exposure which mimics the route of natural infection. Forty-five per cent of pre-clinical fish tested yielded positive results by RT-PCR for at least one of the organs tested (kidney, heart, gill, liver, blood). No significant difference was detected between organs in the number or time of first occurrence of positive result. Virus culture identified a total of 14% of pre-clinical fish as ISAV-infected. The presence of ISAV in heart tissue was particularly notable (13% of fish sampled) as was the inability to culture virus from spleen tissue. In the case of IFAT, 15% of fish sampled were positive, although tissue other than kidney proved unsuitable for use in this method. Only limited ISAV-specific pathology was detectable by histological examination of fish prior to the onset of clinical disease. These findings reveal important information regarding the optimal choice of both tissue sample and diagnostic test for the routine diagnosis of ISAV.

Determination of midazolam and 1'-hydroxymidazolam by liquid chromatography-mass spectrometry in plasma of patients undergoing methadone maintenance treatment

A rapid, sensitive and selective LC-MS method was developed for the simultaneous determination of midazolam (MDZ) and 1'-hydroxymidazolam (1'-OHMDZ) in plasma taken from 54 patients undergoing methadone maintenance therapy, most of whom were multidrug users. Samples spiked with prazepam, the internal standard, and were extracted into diethyl ether. Compounds were separated on a Phenomenex Luna C(18) column and a mobile phase of acetonitrile-ammonium acetate buffer (10 mM, pH 4.7) (52:48, v/v) at a flow-rate of 1 ml/min. The limit of detection was 0.65 and 0.68 (ng/ml) for MDZ and 1'-OHMDZ, respectively. Within-day relative standard deviations were less than 8%.

Detection of infectious salmon anaemia virus (ISAV) by in situ hybridisation

An in situ hybridisation method was developed to detect infectious salmon anaemia virus (ISAV) in fixed tissues from Atlantic salmon Salmo salar L. Three DNA probes detected ISAV in heart, liver, kidney, spleen, caeca, and mid-gut from infected farmed Atlantic salmon obtained from a natural outbreak of ISA. The strongest signals were obtained using Probe S8, from Segment 8 of ISAV. Hybridisation was most prominent in the endothelial cells of heart tissue. The probes reacted specifically with ISAV; no hybridisation was evident in uninfected tissues from Atlantic salmon. Importantly, the probes did not cross react with the pathogens IHNV (haematopoietic necrosis virus), IPNV (infectious pancreatic necrosis virus), SPDV (salmon pancreas disease virus) and VHSV (viral haemorrhagic septicemia virus).

Infectious salmon anaemia virus in wild fish from Scotland

Following the outbreak of infectious salmon anaemia (ISA) at salmon farms in Scotland, UK, a survey was established to determine the extent of infection in wild fish. All fish tested were free from the clinical symptoms of ISA. Isolations of ISAV were made from 5 sea trout within areas where ISA affected salmon farms were located. Evidence for ISAV in other sea trout was provided by ISA RT-PCR diagnostic tests. Results from ISA RT-PCR tests reveal evidence for ISAV being present in salmon parr, adult salmon and juvenile brown trout in rivers distant from salmon farms and indicate that, at the time of the survey (1998-1999), ISAV may have been widely distributed. Nucleotide sequence analysis of segments 2 and 8 showed that for most sequences from wild fish there was 100% homology with ISAV isolated from clinically affected farmed fish although evidence is presented which indicates variability in ISAV sequences from wild fish. Modelling the RT-PCR findings indicates that ISAV among salmonid fish was spatially non-random. Brown trout, sea trout and salmon (adult and parr) show a pattern of occasionally large numbers of positive samples against a background of very low numbers.

The antitussive effect of dextromethorphan in relation to CYP2D6 activity

AIMS

To test the hypothesis that inhibition of cytochrome P450 2D6 (CYP2D6) by quinidine increases the antitussive effect of dextromethorphan (DEX) in an induced cough model.

METHODS

Twenty-two healthy extensive metaboliser phenotypes for CYP2D6 were studied according to a double-blind, randomised cross-over design after administration of: (1) Placebo antitussive preceded at 1 h by placebo inhibitor; (2) 30 mg oral DEX preceded at 1 h by placebo inhibitor (DEX30); (3) 60 mg oral DEX preceded at 1 h by placebo inhibitor (DEX60); (4) 30 mg oral DEX preceded at 1 h by 50 mg oral quinidine sulphate (QDEX30). Cough frequency following inhalation of 10% citric acid was measured at baseline and at intervals up to 12 h. Plasma concentrations of DEX and its metabolites were measured up to 96 h by h.p.l.c.

RESULTS

Inhibition of CYP2D6 by quinidine caused a significant increase in the mean ratio of DEX to dextrorphan (DEX:DOR) plasma AUC(96) (0.04 vs 1.81, P<0.001). The mean (+/-s.d.) decrements in cough frequency below baseline over 12 h (AUEC) were: 8% (11), 17% (14.5), 25% (16.2) and 25% (16.9) for placebo, DEX30, DEX60 and QDEX30 treatments, respectively. Statistically significant differences in antitussive effect were detected for the contrasts between DEX60/placebo (P<0.001; 95% CI of difference +80, +327) and QDEX30/placebo (P<0.001, +88, +336), but not for DEX30/placebo, DEX30/DEX60 or DEX30/QDEX30 (P=0.071, -7, +241; P=0.254, -37, +211; P=0.187, -29, +219, respectively).

CONCLUSIONS

A significant antitussive effect was demonstrated after 60 mg dextromethorphan and 30 mg dextromethorphan preceded by 50 mg quinidine using an induced cough model. However, although the study was powered to detect a 10% difference in cough response, the observed differences for other contrasts were less than 10%, such that it was possible only to imply a dose effect (30 vs 60 mg) in the antitussive activity of DEX and enhancement of this effect by CYP2D6 inhibition.

The relationship between anthropometric measurements at birth: asthma and atopy in childhood

BACKGROUND

Recent studies have reported that a large head circumference at birth is associated with an increased risk of raised serum IgE in adult life, and asthma during childhood.

OBJECTIVE

To examine the relationship between head circumference and other anthropometric measurements at birth and asthma and indices of atopy in childhood.

METHODS

The presence of asthma and measures of atopic status (total serum IgE level and skin prick tests to common allergens) were assessed prospectively in offspring of families participating in a community-based genetic study in Southampton, UK. Measures of perinatal variables including birth weight, head circumference at birth, and gestational age were obtained from hospital records of 239 offspring aged 6-23 years.

RESULTS

Children with a head circumference of 37 cm or more at birth had a relative risk of an elevated serum total IgE (> 150 IU) of 3.2 (95% CI 1.0-10.4). There were no consistent relationships between head circumference at birth and either skin prick positivity or the development of clinical asthma. There was no significant association between other perinatal markers and measures of atopic status or clinical asthma.

CONCLUSION

The study has identified that a large head circumference at birth is associated with an increased risk of an elevated total serum IgE in childhood. The reasons for this association, and the lack of an association with asthma are unclear and will require further research.

The so-called "placebo effect" in benign prostatic hyperplasia treatment trials represents partially a conditional regression to the mean induced by censoring

OBJECTIVES

To study the variability of assessment instruments (symptom questionnaires and flow rate recordings) in healthy volunteers during repeat administration in short intervals. To study the effect of inclusion criteria-based censoring of patients during screening for benign prostatic hyperplasia (BPH) treatment trials on the outcome of subsequent tests.

METHODS

One hundred forty-five male volunteers without known prostatic diseases with a mean age of 52 years (range 23 to 83) were given the American Urological Association (AUA) Symptom Index (SI), BPH Impact Index (II). Quality of Life (QOL) score, and a flow rate recording twice 10 to 20 days apart without any healthcare intervention. Data were collected and analyzed after typical BPH trial criteria were applied to the first test, and patients who did not "qualify" were censored.

RESULTS

Good correlation exists between two closely spaced administrations of the AUA SI, BPH II, QOL score, and flow rate recordings in healthy male volunteers with correlation coefficients between 0.73 and 0.89. Censoring patients and excluding them from the analysis of the second test based on typical BPH trial criteria induces a regression to the mean phenomenon, which results in an artificial improvement in these outcome parameters. The magnitude of the improvement increases as the selection and censoring criteria tighten. The mean differences between the first and second test range from 1.4 to 1.7 mL/s for the peak flow rate, from -1.0 to -1.4 for the AUA SI, and from -0.4 to -0.8 for the BPH II. All these differences induced solely by censoring with resulting regression to the mean are statistically significant.

CONCLUSIONS

Censoring of patients based on inclusion and exclusion criteria is typical for BPH treatment trials. One of the under-recognized effects of censoring is a regression to the mean, which leads to an apparent improvement in the outcome parameters assessed. In both placebo or sham-controlled trials, as well as in clinical series without controls, one must keep this effect and its relative magnitude in mind, and interpret the data from such trials with appropriate caution.