Outcomes of COVID-19 in people with rheumatic and musculoskeletal disease in Ireland over the first 2 years of the pandemic

BACKGROUND

Poor COVID-19 outcomes occur with higher frequency in people with rheumatic and musculoskeletal diseases (RMD). Better understanding of the factors involved is crucial to informing patients and clinicians regarding risk mitigation.

AIM

To describe COVID-19 outcomes for people with RMD in Ireland over the first 2 years of the pandemic.

METHODS

Data entered into the C19-GRA provider registry from Ireland between 24th March 2020 and 31st March 2022 were analysed. Differences in the likelihood of hospitalisation and mortality according to demographic and clinical variables were investigated.

RESULTS

Of 237 cases included, 59.9% were female, 95 (41.3%) were hospitalised, and 22 (9.3%) died. Hospitalisation was more common with increasing age, gout, smoking, long-term glucocorticoid use, comorbidities, and specific comorbidities of cardiovascular and pulmonary disease, and cancer. Hospitalisation was less frequent in people with inflammatory arthritis and conventional synthetic or biologic disease-modifying antirheumatic drug use. Hospitalisation had a U-shaped relationship with disease activity, being more common in both high disease activity and remission. Mortality was more common with increasing age, gout, smoking, long-term glucocorticoid use, comorbidities, and specific comorbidities of cardiovascular disease, pulmonary disease, and obesity. Inflammatory arthritis was less frequent in those who died.

CONCLUSION

Hospitalisation or death were more frequently experienced by RMD patients with increasing age, certain comorbidities including potentially modifiable ones, and certain medications and diagnoses amongst other factors. These are important 'indicators' that can help risk-stratify and inform the management of RMD patients.

Where to live? Landfast sea ice shapes emperor penguin habitat around Antarctica

Predicting species survival in the face of climate change requires understanding the drivers that influence their distribution. Emperor penguins (Aptenodytes forsteri) incubate and rear chicks on landfast sea ice, whose extent, dynamics, and quality are expected to vary substantially due to climate change. Until recently, this species' continent-wide observations were scarce, and knowledge on their distribution and habitat limited. Advances in satellite imagery now allow their observation and characterization of habitats across Antarctica at high resolution. Using circumpolar high-resolution satellite images, unique fast ice metrics, and geographic and biological factors, we identified diverse penguin habitats across the continent, with no significant difference between areas with penguins or not. There is a clear geographic partitioning of colonies with respect to their defining habitat characteristics, indicating possible behavioral plasticity among different metapopulations. This coincides with geographic structures found in previous genetic studies. Given projections of quasi-extinction for this species in 2100, this study provides essential information for conservation measures.

Biological responses to change in Antarctic sea ice habitats

Sea ice is a key habitat in the high latitude Southern Ocean and is predicted to change in its extent, thickness and duration in coming decades. The sea-ice cover is instrumental in mediating ocean–atmosphere exchanges and provides an important substrate for organisms from microbes and algae to predators. Antarctic krill, Euphausia superba, is reliant on sea ice during key phases of its life cycle, particularly during the larval stages, for food and refuge from their predators, while other small grazers, including copepods and amphipods, either live in the brine channel system or find food and shelter at the ice-water interface and in gaps between rafted ice blocks. Fish, such as the Antarctic silverfish Pleuragramma antarcticum, use platelet ice (loosely-formed frazil crystals) as an essential hatching and nursery ground. In this paper, we apply the framework of the Marine Ecosystem Assessment for the Southern Ocean (MEASO) to review current knowledge about relationships between sea ice and associated primary production and secondary consumers, their status and the drivers of sea-ice change in this ocean. We then use qualitative network modelling to explore possible responses of lower trophic level sea-ice biota to different perturbations, including warming air and ocean temperatures, increased storminess and reduced annual sea-ice duration. This modelling shows that pelagic algae, copepods, krill and fish are likely to decrease in response to warming temperatures and reduced sea-ice duration, while salp populations will likely increase under conditions of reduced sea-ice duration and increased number of days of >0°C. Differences in responses to these pressures between the five MEASO sectors were also explored. Greater impacts of environmental pressures on ice-related biota occurring presently were found for the West and East Pacific sectors (notably the Ross Sea and western Antarctic Peninsula), with likely flow-on effects to the wider ecosystem. All sectors are expected to be impacted over coming decades. Finally, we highlight priorities for future sea ice biological research to address knowledge gaps in this field.

Predictors of hospitalization in patients with rheumatic disease and COVID-19 in Ireland: data from the COVID-19 global rheumatology alliance registry

Objectives

Given the limited data regarding the risk of hospitalization in patients with rheumatic disease and coronavirus disease 2019 (COVID-19) in Ireland, we used the COVID-19 Global Rheumatology Alliance (GRA) registry data to study outcomes and their predictors. The primary objective was to explore potential predictors of hospitalization.

Methods

We examined data on patients and their disease-related characteristics entered in the COVID-19 GRA provider registry from Ireland (from 24 March 2020 to 31 August 2020). Multivariable logistic regression was used to assess the association of demographic and clinical characteristics with hospitalization.

Results

Of 105 patients, 47 (45.6%) were hospitalized and 10 (9.5%) died. Multivariable logistic regression analysis showed that age [odds ratio (OR) = 1.06, 95% CI 1.01, 1.10], number of co-morbidities (OR = 1.93, 95% CI 1.11, 3.35) and glucocorticoid use (OR = 15.01, 95% CI 1.77, 127.16) were significantly associated with hospitalization. A diagnosis of inflammatory arthritis was associated with lower odds of hospitalization (OR = 0.09, 95% CI 0.02, 0.32).

Conclusion

Increasing age, co-morbidity burden and glucocorticoid use were associated with hospitalization, whereas a diagnosis of inflammatory arthritis was associated with lower odds of hospitalization.

Landfast ice: a major driver of reproductive success in a polar seabird

In a fast-changing world, polar ecosystems are threatened by climate variability. Understanding the roles of fine-scale processes, and linear and nonlinear effects of climate factors on the demography of polar species is crucial for anticipating the future state of these fragile ecosystems. While the effects of sea ice on polar marine top predators are increasingly being studied, little is known about the impacts of landfast ice (LFI) on this species community. Based on a unique 39-year time series of satellite imagery and in situ meteorological conditions and on the world's longest dataset of emperor penguin (Aptenodytes forsteri) breeding parameters, we studied the effects of fine-scale variability of LFI and weather conditions on this species' reproductive success. We found that longer distances to the LFI edge (i.e. foraging areas) negatively affected the overall breeding success but also the fledging success. Climate window analyses suggested that chick mortality was particularly sensitive to LFI variability between August and November. Snowfall in May also affected hatching success. Given the sensitivity of LFI to storms and changes in wind direction, important future repercussions on the breeding habitat of emperor penguins are to be expected in the context of climate change.

Prevalence and treatment of gout among patients with chronic kidney disease in the Irish health system: A national study

Background

Gout is a common inflammatory arthritis associated with adverse clinical outcomes. Under treatment is common in the general population. The aim of this study was to determine the prevalence of gout and its treatment among patients with chronic kidney disease (CKD).

Methods

We conducted a multi-centre cross sectional study of patients (n = 522) who attended specialist nephrology clinics in Ireland. Standardized data collection tool recorded clinical characteristics and medication use at clinic visits and kidney function was assessed with standardised creatinine measurements and Estimated Glomerular Filtration Rate (eGFR). The prevalence of gout and the corresponding use of urate lowering therapies (ULT) were determined. Multivariate logistic regression explored correlates of gout expressed as Odds Ratios (OR) and 95% Confidence Intervals (CI) adjusting for demographic and clinical characteristics.

Results

Overall prevalence of gout was 16.6% and increased significantly from 7.5% in Stage 1–2 CKD to 22.8% in stage 4–5 CKD, P< 0.005. Prevalence increased with age (P < 0.005) and was higher in men than women (19.1% versus 10.3% P< 0.005). Overall, 67.9% of gout patients with CKD were treated with ULT, and the percentage increased with advancing stage of CKD from 55.6% in Stage 1–2 to 77.4% in Stage 4–5, P<0.005. Multivariable modelling identified men (vs women), OR, 1.95 (0.95–4.03), serum albumin, OR 1.09 (1.02–1.16) per 1 g/L lower, poorer kidney function, OR 1.11 (1.01–1.22) per 5 ml/min/1.73m² lower, and rising parathyroid hormone levels, OR 1.38 (1.08–1.77) per 50 pg/ml higher as disease correlates.

Conclusions

Gout is common in CKD and increases with worsening kidney function in the Irish health system. Over two thirds of patients with gout were receiving ULT, increasing to 77% of patients with advanced CKD. Greater awareness of gout in CKD, its treatment and the effectiveness of treatment strategies should be vigorously monitored to improve patient outcomes.

New insights into Behçet's disease in Ireland: the Midwest cohort study

OBJECTIVES

The epidemiology of Behçet's disease (BD) remains poorly understood with limited international data on disease burden, progression and treatment outcomes. The aims of this study were to determine the natural history of BD in the Midwest region of Ireland and compare our findings with those from other European and Mediterranean studies.

METHODS

We established a cohort of patients with BD in the Midwest Region of Ireland based on ISGBD and/or ICBD criteria. Longitudinal data were captured on demographic and clinical characteristics, disease activity and clinical outcomes.

RESULTS

The cohort included 24 Caucasian patients (16 women, 8 men) and one male patient with Middle Eastern ancestry, who satisfied the diagnostic criteria for BD. Based on the ISGBD criteria, the point prevalence of BD was 6.2 per 100,000 population. The most common clinical manifestation was oral aphthosis (100%) followed by genital aphthosis (92%) and skin lesions (92%), arthralgia/arthritis (40%), ocular involvement (32%), vascular thrombosis (12%) and pathergy phenomenon (8%). Only 1 patient was HLA-B*51 positive. A long-term multidisciplinary approach that included physician specialists, nurse specialists, and general practitioners was adopted for ongoing patient care.

CONCLUSIONS

The prevalence of BD in Ireland is higher than previously reported with a significant proportion experiencing laryngeal destruction. There are many similarities as well as several differences in the epidemiology of BD by country and indeed within countries. We fully advocate the need for national and international collaborative efforts in order to further understand the complex aetiology and immunopathology of BD in order to improve the clinical, physical, psychological wellbeing of patients.

Temporal trends in hyperuricaemia in the Irish health system from 2006-2014: A cohort study

Background

Elevated serum uric acid (sUA) concentrations are common in the general population and are associated with chronic metabolic conditions and adverse clinical outcomes. We evaluated secular trends in the burden of hyperuricaemia from 2006–2014 within the Irish health system.

Methods

Data from the National Kidney Disease Surveillance Programme was used to determine the prevalence of elevated sUA in adults, age > 18 years, within the Irish health system. Hyperuricaemia was defined as sUA > 416.4 μmol/L in men and > 339.06 μmol/L in women, and prevalence was calculated as the proportion of patients per year with mean sUA levels above sex-specific thresholds. Temporal trends in prevalence were compared from 2006 to 2014 while general estimating equations (GEE) explored variation across calendar years expressed as odds ratios (OR) and 95% Confidence intervals (CI).

Results

From 2006 to 2014, prevalence of hyperuricaemia increased from 19.7% to 25.0% in men and from 20.5% to 24.1% in women, P<0.001. The corresponding sUA concentrations increased significantly from 314.6 (93.9) in 2006 to 325.6 (96.2) in 2014, P<0.001. Age-specific prevalence increased in all groups from 2006 to 2014, and the magnitude of increase was similar for each age category. Adjusting for baseline demographic characteristics and illness indicators, the likelihood of hyperuricemia was greatest for patients in 2014; OR 1.45 (1.26–1.65) for men and OR 1.47 (1.29–1.67) in women vs 2006 (referent). Factors associated with hyperuricaemia included: worsening kidney function, elevated white cell count, raised serum phosphate and calcium levels, elevated total protein and higher haemoglobin concentrations, all P<0.001.

Conclusions

The burden of hyperuricaemia is substantial in the Irish health system and has increased in frequency over the past decade. Advancing age, poorer kidney function, measures of nutrition and inflammation, and regional variation all contribute to increasing prevalence, but these do not fully explain emerging trends.

The impact of exercise on sleep (time, quality, and disturbance) in patients with rheumatoid arthritis: a study protocol for a pilot randomised controlled trial

Poor sleep is an issue for people with rheumatoid arthritis (RA), which may curtail their ability to function appropriately and reduce their activity levels. This paper describes a protocol for a pilot randomised controlled trial of an aerobic exercise intervention compared with exercise advice designed to improve sleep in people with RA. Objectives are to obtain reliable estimates regarding recruitment rates, participant retention and protocol adherence and to generate potential effect size estimates for a main trial. Participants will be identified from an existing database held at a University Hospital and in person at weekly rheumatology clinics. Participants meeting the inclusion criteria will be randomised into an intervention or control group. Those in the intervention group will participate in an 8-week walking-based exercise intervention consisting of 28 walking sessions, with 1 session per week being supervised by a trained physiotherapist, spread over a maximum of 8 weeks (2-5 times/week), while those in the control group will receive advice on the benefits of exercise for people with RA. Results will provide data for efficient recruitment and data collection, to determine if a larger, statistically powered main trial could be generalised to a multi-centre rheumatoid arthritis population. Given recent information that sleep is commonly reduced in people with RA and that physical activity and exercise profiles are lower, this study will contribute data to the field of exercise and sleep that is currently lacking and importantly will include people with RA in the study process prior to any fully powered trial.Trial registration number: ClinicalTrials.gov Identifier: NCT03140995 (April 25th, 2017).

Variability in sea ice cover and climate elicit sex specific responses in an Antarctic predator

Contrasting regional changes in Southern Ocean sea ice have occurred over the last 30 years with distinct regional effects on ecosystem structure and function. Quantifying how Antarctic predators respond to such changes provides the context for predicting how climate variability/change will affect these assemblages into the future. Over an 11-year time-series, we examine how inter-annual variability in sea ice concentration and advance affect the foraging behaviour of a top Antarctic predator, the southern elephant seal. Females foraged longer in pack ice in years with greatest sea ice concentration and earliest sea ice advance, while males foraged longer in polynyas in years of lowest sea ice concentration. There was a positive relationship between near-surface meridional wind anomalies and female foraging effort, but not for males. This study reveals the complexities of foraging responses to climate forcing by a poleward migratory predator through varying sea ice property and dynamic anomalies.

The suppression of Antarctic bottom water formation by melting ice shelves in Prydz Bay

A fourth production region for the globally important Antarctic bottom water has been attributed to dense shelf water formation in the Cape Darnley Polynya, adjoining Prydz Bay in East Antarctica. Here we show new observations from CTD-instrumented elephant seals in 2011–2013 that provide the first complete assessment of dense shelf water formation in Prydz Bay. After a complex evolution involving opposing contributions from three polynyas (positive) and two ice shelves (negative), dense shelf water (salinity 34.65–34.7) is exported through Prydz Channel. This provides a distinct, relatively fresh contribution to Cape Darnley bottom water. Elsewhere, dense water formation is hindered by the freshwater input from the Amery and West Ice Shelves into the Prydz Bay Gyre. This study highlights the susceptibility of Antarctic bottom water to increased freshwater input from the enhanced melting of ice shelves, and ultimately the potential collapse of Antarctic bottom water formation in a warming climate.

Antarctic bottom water (AABW) production is critical to the global ocean overturning circulation. Here, the authors show new observations of AABW formation from seal CTD data in Prydz Bay, East Antarctica that highlights its susceptibility to increased freshwater input from the melting of ice shelves.

Relationship between self-efficacy, beliefs, and physical activity in inflammatory arthritis

Background:

The benefits of physical activity (PA) in inflammatory arthritis (IA) patients are well-established. However, levels of PA in the IA population are suboptimal and the psychological determinants of PA are poorly understood.

Objective:

The study aimed to examine the self-reported PA levels and psychological determinants of PA for the IA population.

Methods:

A cross-sectional study of people with rheumatoid arthritis (RA) and psoriatic arthritis (PsA) was conducted to explore the association between demographic and psychological variables such as self-efficacy and belief about PA, and levels of PA and energy expenditure (EE). PA was recorded using the Yale Physical Activity Survey (YPAS).

Results:

A total of 102 participants were included in the study. Participants reported low levels of PA [mean ± standard deviation (SD), 24.3 ± 18.2]. Beliefs about PA, but not self-efficacy, correlated with levels of self-report PA over the past week (r = 0.25, p = 0.01), over the past month (r = 0.21, p = 0.04), and EE (r = 0.31, p = 0.01).

Conclusion:

People with IA have decreased levels of PA. Beliefs about PA are associated with levels of self-report PA and EE in this population. These data provide a useful signpost for guiding and designing interventions to improve PA levels in IA populations by altering beliefs about PA.

Clinical and imaging efficacy of infliximab in HLA-B27-Positive patients with magnetic resonance imaging-determined early sacroiliitis

OBJECTIVE

To evaluate the efficacy of infliximab in HLA-B27-positive patients with magnetic resonance imaging (MRI)-determined early sacroiliitis, using both clinical and MRI assessments.

METHODS

Forty patients with recent-onset inflammatory back pain, as assessed by the Calin criteria, HLA-B27 positivity, clinical disease activity as measured by the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), pain and morning stiffness, and magnetic resonance imaging (MRI)-determined sacroiliac joint bone edema were randomized in a double-blind manner to receive infliximab 5 mg/kg or placebo at 0, 2, 6, and 12 weeks. MRI scans were performed at baseline and 16 weeks and scored by 2 observers (blinded to both the order of the scans and to treatment group), using the Leeds scoring system. Clinical assessments included the BASDAI, the Bath Ankylosing Spondylitis Functional Index (BASFI), the Ankylosing Spondylitis Quality of Life (ASQoL) instrument, the ASsessment in Ankylosing Spondylitis International Working Group criteria (ASAS) for improvement, and markers of inflammation.

RESULTS

The mean reduction in the total MRI score from week 0 to week 16 was significantly greater in infliximab-treated patients compared with placebo-treated patients (P = 0.033). On average, significantly more lesions resolved in the infliximab group (P < 0.001), while significantly more new lesions developed in the placebo group (P = 0.004). Significantly greater improvement in the infliximab group versus the placebo group was also observed for changes from week 0 to week 16 in the BASDAI (P = 0.002), BASFI (P = 0.004), and ASQoL (P = 0.007) scores. Responses according to the ASAS criteria for 40% improvement, the ASAS criteria for 20% improvement in 5 of 6 domains, and ASAS partial remission were achieved by 61%, 44%, and 56% of infliximab-treated patients, respectively. Infliximab was well tolerated, and no serious adverse events were observed.

CONCLUSION

Infliximab was an effective therapy for early sacroiliitis, providing a reduction in disease activity by week 16. This study is the first to show that infliximab is effective for reducing clinical and imaging evidence of disease activity in patients with MRI-determined early axial spondylarthritis.

Liver fibrosis in patients with psoriasis and psoriatic arthritis on long-term, high cumulative dose methotrexate therapy

OBJECTIVES

Dermatologists and rheumatologists have differed in their use of serial liver biopsy and liver function tests (LFT) to monitor the risk of hepatic fibrosis in long-term MTX therapy. It is judged safe to monitor LFT only in RA. Whilst there are few studies in PsA to justify this approach, it is widely used in rheumatology practice. The study aimed to assess prevalence of hepatic fibrosis in both psoriasis and PsA patients on long-term MTX therapy.

METHODS

A prospective study of 54 patients with psoriatic disease had a liver biopsy according to dermatology guidelines on long-term MTX treatment with full assessment of risk factors. Previously, monitoring these patients was in accordance with ACR guidelines with 3-monthly LFT.

RESULTS

MTX treatment duration was a mean of 6.9 years, with a mean cumulative dose of 4396 mg. There were no cases of advanced fibrosis or of cirrhosis and mild early fibrosis in 11 (22%) patients. The presence of early mild changes was related to the number of risk factors that the patient had for hepatic fibrosis [also the risk factors for non-alcoholic steatohepatitis (NASH)]. Pro-collagen 3 N-terminal peptide (PIIINP) was unhelpful in PsA and frequently elevated despite normal liver biopsy.

CONCLUSIONS

Despite other risk factors for NASH, monitoring for hepatic fibrosis using serial liver function and ACR guidelines tests alone as in RA appears safe in psoriasis and PsA. Liver biopsy ought to be considered to assess the liver if LFT are persistently elevated. PIIINP is misleading in active PsA.

Estimating the cost and health status consequences of treatment with TNF antagonists in patients with psoriatic arthritis

OBJECTIVES

Tumour necrosis factor (TNF) has been shown to improve the outcomes in patients with psoriatic arthritis (PsA). We estimate the long-term impact on health status of prescribing the TNF antagonist etanercept, and evaluate the cost-effectiveness in a health economic model.

METHODS

The relationship between disability (Health Assessment Questionnaire) and health state utility was explored to estimate the quality-adjusted life years (QALYs) gained from the TNF antagonist etanercept. A model was then used to compare sequences of treatments for PsA after failure of two conventional disease modifying anti-rheumatic drugs (DMARDs). One arm commences on etanercept therapy and this is compared with a strategy commencing with combination therapy of methotrexate and ciclosporin and another commencing with leflunomide. Individual patient data from Phase III etanercept trials is used to populate the model supported by published evidence from extensive literature searches. By incorporating a life table specific for a PsA population, and using a number of evidence- and expert opinion-based assumptions for disease progression, the model was extended beyond the trial duration to a 10-yr time horizon. Cost offsets were produced by avoiding surgery through delayed progression; drug and monitoring costs were also modelled.

RESULTS

Over the 10 yrs, modelled etanercept treatment gave 0.82 more QALYs when compared with combination therapy with methotrexate and ciclosporin, and 0.65 more QALYs in comparison with leflunomide. This equates to a central estimate for the cost per QALY of pound28 189 and pound28 189 for ciclosporin and leflunomide, respectively. Sensitivity analyses demonstrated this could vary by as much as +/-28%.

CONCLUSIONS

With limited data currently available, the potential cost-effectiveness of etanercept in DMARD failures for adults with PsA appears encouraging. The result for other TNF antagonists will depend on how their relative efficacy and drug price compares with etanercept. A number of limitations are described and priorities for further research suggested.

A randomised, double blind, placebo controlled, multicentre trial of combination therapy with methotrexate plus ciclosporin in patients with active psoriatic arthritis

OBJECTIVES

To evaluate the safety and efficacy of adding ciclosporin A (CSA) to the treatment of patients with psoriatic arthritis (PsA) demonstrating an incomplete response to methotrexate (MTX) monotherapy.

METHODS

In a 12 month, randomised, double blind, placebo controlled trial at five centres in three countries, 72 patients with active PsA with an incomplete response to MTX were randomised to receive either CSA (n = 38) or placebo (n = 34). Patients underwent full clinical and radiological assessment and, in addition, high resolution ultrasound (HRUS) was performed at one centre. An intention to treat (last observation carried forward) analysis was employed.

RESULTS

Some significant improvements were noted at 12 months in both groups. However, in the active but not the placebo arm there were significant improvements in swollen joint count, mean (SD), from 11.7 (9.7) to 6.7 (6.5) (p<0.001) and C reactive protein, from 17.4 (14.5) to 12.7 (14.3) mg/l (p<0.05) as compared with baseline. The Psoriasis Area and Severity Index (PASI) score improved in the active group (2 (2.3) to 0.8 (1.3)) as compared with placebo (2.2 (2.7) to 1.9 (2.8)), p<0.001, and synovitis detected by HRUS (33 patients, 285 joints) was reduced by 33% in the active group compared with 6% in the placebo group (p<0.05). No improvement in Health Assessment Questionnaire or pain scores was detected.

CONCLUSIONS

Synovitis detected by HRUS was significantly reduced. Combining CSA and MTX treatment in patients with active PsA, and a partial response to MTX, significantly improves the signs of inflammation but not pain or quality of life.

Adequate early cyclosporin exposure is critical to prevent renal allograft rejection: patients monitored by absorption profiling

This study used receiver operating characteristic analysis to investigate the properties of area under the concentration-time curve during the first 4h after cyclosporin-microemulsion dosing (AUC0-4) and cyclosporin (CyA) levels immediately before and at 2 and 3h after dosing (C0, C2 and C3) to predict the risk of biopsy-proven acute rejection (AR) at 6 months. Ninety-eight kidney transplant recipients treated with CyA-microemulsion-based triple therapy immunosuppression were studied on post-transplant days 3, 5, and 7, and at increasing intervals thereafter. The most sensitive and specific predictor of AR was AUC0-4. Of the single time-point measurements, the measurement properties of C2 were closest to those of AUC0-4, and superior to those of C3. The relationship between C0 and subsequent AR was weak and did not reach statistical significance. On day 3, CyA AUC0-4 > or = 4,400 ng.h/mL and C2 > or = 1,700 ng/mL were each associated with a 92% negative predictive value for rejection in the first 6months. Pharmacokinetic measurements on or after day 5, and measurements on day 3 in patients with delayed graft function, were not predictive of AR. Adequate exposure within the first 3days post transplantation may be critically important in preventing subsequent rejection.

Sertraline-induced hypoglycemia

OBJECTIVE

To report a case of hypoglycemia that occurred in a patient treated with the selective serotonin-reuptake inhibitor, sertraline.

CASE SUMMARY

An 82-year-old white woman with mild cardiovascular disease and no history of glucose intolerance was seen in the emergency department for a presyncopal episode associated with a blood glucose of 32 mg/dL as measured by the ambulance attendant. She had similar symptoms the day before. Despite repeated administration of oral and intravenous glucose, the patient had recurrent episodes of hypoglycemia and was hospitalized for four days. She had started taking sertraline 50 mg once daily for mild depression 25 days prior to presentation. Other medications included furosemide 20 mg/d, ramipril 5 mg/d, clopidogrel 75 mg/d, nitroglycerin patch 0.4 mg/h, and lorazepam 1 mg taken occasionally for agitation. She had never been prescribed any oral hypoglycemic agents. Serum sertraline and desmethylsertraline concentrations measured two, three, and four days after discontinuing sertraline were within the expected range, but the rate of decline was consistent with a moderately prolonged half-life.

DISCUSSION

Sertraline has been shown to blunt postprandial hyperglycemia in rats and to potentiate the hypoglycemic effects of sulfonylurea agents in humans. It has not been reported to cause hypoglycemia independently, but in this case, a nondiabetic patient experienced multiple episodes of hypoglycemia that resolved after discontinuation of sertraline.

CONCLUSIONS

This report and another implicating fluoxetine in a case of hypoglycemia suggest that healthcare professionals should consider these medications among the possible causes of hypoglycemia occurring in patients receiving selective serotonin-reuptake inhibitors.

A simple method to estimate the required dialysis time for cases of alcohol poisoning

BACKGROUND

Conventional dialysis management of ethylene glycol and methanol poisoning includes frequent intradialytic determinations of serum toxin concentration. Dialysis is continued until a target toxin concentration is reached. Initially, the required dialysis duration is unknown, making planning difficult. We devised a simple method to estimate the duration of dialysis required and avoid quantitation of multiple toxin samples.

METHODS

Using the assumption that toxic alcohols would have a dialysis clearance similar to urea, we proposed that required dialysis time (hours) to reach a 5 mmol/L toxin concentration target would be: [-V ln(5/A)]/0.06k, where V (liters) is the Watson estimate of total body water, A is the initial toxin concentration (mmol/L), and k is 80% of the manufacturer-specified dialyzer urea clearance (mL/min) at the initial observed blood flow rate. Directly measured dialysis and renal toxin clearance, and true dialysis requirement by conventional treatment protocol were compared with our estimate in two methanol and three ethylene glycol poisonings treated with Fresenius F8 dialyzers.

RESULTS

There were no clinically or statistically significant differences between predicted dialysis duration (7.6 +/- 1.9 hours, +/-SD) and that actually provided using hourly toxin concentration sampling (7.4 +/- 1.9 hours). Renal toxin clearance was negligible compared to that of dialysis, and predicted dialysis clearance did not differ significantly from that observed.

CONCLUSIONS

The simple estimate method is sufficiently valid to guide the prescription of dialysis for toxic alcohol poisoning. Data required at dialysis start include only the initial toxin concentration, dialyzer manufacturer's specified urea clearance at initial observed blood pump speed, and patient demographics to estimate total body water. This approach allows for planned dialysis therapy, without the need for additional toxin concentration measurements until dialysis is completed.

A 6-year experience with urine drug testing by family service agencies in Nova Scotia, Canada

The objective of this study is to describe a urine drug-testing program implemented for parents with a history of substance abuse by family service agencies in the province of Nova Scotia, Canada. Nurse collectors went to the parents' home to obtain urine specimens under direct observation and then delivered the specimens to the toxicology laboratory or arranged shipment by courier under chain of custody. Each urine specimen was screened for cannabinoids, cocaine metabolite, opiates, amphetamines and benzodiazepines, ethyl alcohol and creatinine. All positive screening tests were confirmed by another method such as gas chromatography-mass spectrometry (GC-MS). In 15,979 urine specimens collected from 1994 to 1999, the percent positive rate for one (or more) drugs/metabolites ranged from 45.6% (1994-1996) to 30.0% (1998, 1999). A total of 575 specimens (3.7%) were dilute (urine creatinine <25mg/dl). Positive rates in 15,404 non-dilute specimens from 1994 to 1999 were as follows: cannabinoids - 11.7%, benzodiazepines - 11.3%, cocaine metabolite - 3.7%, and ethyl alcohol - 2.6%. Most clients provided less than 20 urine specimens for testing but some individuals submitted urine specimens more than 100 times in a 12-15-month period. Urine drug screening in parents with a history of substance abuse provided an objective and reliable indication of recent drug use in this population.

Experience with urine drug testing by the Correctional Service of Canada

The Correctional Service of Canada implemented a urine drug-screening program over 10 years ago. The objective of this report is to describe the program and drug test results in this program for 1999. Offenders in Canadian federal correctional institutions and those living in the community on conditional release were subject to urine drug testing. Urine specimens were collected at correctional facilities and shipped by courier to MAXXAM Analytics Inc. laboratory. All urine specimens were analyzed for amphetamines, cannabinoids, cocaine metabolite (benzoylecgonine), opiates, phencyclidine, benzodiazepines, methyl phenidate, meperidine, pentazocine and fluoxetine by immunoassay screening (homogeneous EIA and ELISA assays) followed by GC-MS confirmation. Ethyl alcohol was analyzed when specifically requested. Alternative screening and confirmation methods with lower cut-off values were used, whenever urine specimens were dilute (creatinine <20mg/dl and specific gravity <or=1.003). The number of urine specimens analyzed was 44,722 in 1999 and 6.2% of these specimens were dilute based on creatinine and specific gravity analysis. The positive rate for one or more drugs was 25.5% in 1999. The highest drug positive rates were for cannabinoids (10.7%), morphine (3.2%), cocaine metabolite (3.2%), codeine (2.6%), oxazepam (2.1%), temazepam (1.1%) and ethyl alcohol (1.0%). In correctional institutions (8606 non-dilute specimens analyzed in 1999), 16.4% were positive for cannabinoids, 4.9% positive for codeine and/or morphine and 2.7% positive for oxazepam and/or temazepam. In the 537 dilute specimens collected in institutions, 21% were positive for cannabinoids, 1.3% positive for codeine and/or morphine and 1.3% positive for oxazepam and/or temazepam. In the community setting, 33,928 non-dilute specimens were collected in 1999 (9.0% were positive for cannabinoids and 3.5% positive for cocaine metabolite). In the 1651 dilute specimens collected from offenders in the community in 1999, 12.6% were positive for cannabinoids and 9.5% positive for cocaine metabolite. We conclude that forensic urine drug testing provides an objective measure of drug use by offenders in Canadian federal institutions and those offenders living in the community on conditional release.

Urinary excretion profiles of 11-nor-9-carboxy-delta9-tetrahydrocannabinol: a delta9-THCCOOH to creatinine ratio study

Monitoring the major cannabinoid metabolite (delta9-THCCOOH) to creatinine ratio (M/C) has been used to predict new drug use. According to Huestis and Cone, the best accuracy (85.4%) for predicting new marijuana use was a ratio > or = 0.5 from two urine specimens collected at least 24 h apart. Manno et al. recommended an M/C ratio of > or = 1.5. Subjects with a history of chronic marijuana use were screened for cannabinoid use by immunoassay (50-ng/mL cutoff), and presumptive positives were confirmed by gas chromatography-mass spectrometry for delta9-THCCOOH (15-ng/mL cutoff). Creatinine was analyzed with a cutoff concentration of 25 mg/dL. The study objective was to apply the criteria from both groups of workers to determine if consecutive urine specimens (collected at least 24 h apart) positive for cannabinoids could be used to differentiate new marijuana use from the excretion of residual cannabinoid metabolite (delta9-THCCOOH) in an uncontrolled setting. Serial urine specimens (826) were collected from 26 individuals. Huestis and Cone and Manno et al. ratios indicated new drug use in 83% and 33% of serial urine specimens collected at least 24 h apart, respectively. Clinically, the Huestis and Cone ratio is recommended because of a lower false-negative rate (7.4%) than the Manno et al. false-negative rate (24%). In legal situations, we recommend using the Manno et al. ratio because of its lower false-positive rate (0.1%) as stated by Huestis and Cone.

Experience with a urine opiate screening and confirmation cutoff of 2000 ng/mL

Until recently, most laboratories used an opiate immunoassay screening and confirmation cutoff value of 300 ng/mL for codeine and morphine detection by gas chromatography-mass spectrometry (GC-MS). The cutoff value for opiates was increased to 2000 ng/mL or higher in various laboratories because of concerns that small doses of codeine and foods containing poppy seeds would give a positive opiate-screening result. Workplace drug-testing programs in the U.S. raised the opiate cutoff value to 2000 ng/mL on 30 November 1998. The objective of this study is to describe the results of opiate testing of 8600 urine specimens collected over 24 months with a 2000-ng/mL screening and confirmation (codeine and morphine) cutoff value. Specimens were screened by the EMITdau opiate assay using an in-house 2000-ng/mL morphine calibrator. Presumptive positive findings (N = 621) were analyzed quantitatively by GC-MS for codeine and morphine. One hundred and eighty six urine specimens were positive for codeine and morphine (> 2000 ng/mL), 298 specimens were positive for codeine only (> 2000 ng/mL) and 26 specimens were positive for morphine only (> 2000 ng/mL). All remaining specimens had codeine and morphine values < 2000 ng/mL. The codeine and morphine confirmation rate in this program reduced from 7.1% in 1994-1996 (300-ng/mL cutoff) to 2.1% in 1997-1998 with a 2000-ng/mL cutoff value. The codeine-only confirmation rate lowered from 6.6% (300-ng/mL cutoff) to 3.4% (2000-ng/mL cutoff). It was concluded that increasing opiate screening and codeine and morphine confirmation cutoff values led to > 300% reduction in the confirmed-positive rate for codeine and morphine and a 47% reduction in codeine-only confirmations in a urine drug-testing program where codeine was the major opiate used.

Glucose protection from MPP+-induced apoptosis depends on mitochondrial membrane potential and ATP synthase

MPP+ inhibits mitochondrial complex I and alpha-ketoglutarate dehydrogenase causing necrosis or apoptosis of catecholaminergic neurons. Low glucose levels or glycolytic blockade has been shown to potentiate MPP+ toxicity. We found that MPP+ caused concentration-dependent apoptosis of neuronally differentiated PC12 cells and that glucose, but not pyruvate, supplementation reduced apoptosis. Oligomycin concentrations sufficient to inhibit ATP synthase blocked the decreased apoptosis afforded by glucose supplementation. Laser-scanning confocal microscope imaging of chloromethyl-tetramethylrosamine methyl ester fluorescence to estimate DeltaPsiM showed that MPP+ and atractyloside reduced DeltaPsiM, while cyclosporin A (CSA) and glucose supplementation reversed decreases in DeltaPsiM caused by MPP+. Oligomycin blocked the effect of glucose supplementation on DeltaPsiM. These findings show that (i) MPP+-induced and atractyloside-induced apoptosis are associated with reduced DeltaPsiM; (ii) CSA maintains DeltaPsiM and reduces MPP+-induced apoptosis; and (iii) glucose supplementation maintains DeltaPsiM, likely by glycolytic ATP-dependent proton pumping at ATP synthase and reduces MPP+-induced apoptosis.

Urine drug testing for social service agencies. A Canadian experience

The introduction of urine drug testing for this program has been considered a success by the social services agencies in Nova Scotia for the following reasons: 1. The results of urine drug testing have been accepted by the Family Courts of Nova Scotia because the urine collection and testing are performed with chain of custody procedures from collection to reporting and the analysis includes confirmation of all positive immunoassay screening tests. 2. Urine drug testing (with established screening and confirmation cut-offs) provides an objective indication of recent drug use compared with relying on self-reporting of drug use. 3. Urine drug testing is believed to be a deterrent to drug use because several individuals with a history of drug use have consistently tested negative for 6 to 12 months (30% of the clients). 4. Some clients with a history of substance abuse are successful in becoming drug free with the support of the social workers and the deterrent effect of random drug testing.

Comparison of four immunoassays for the detection of lorazepam in urine

Four healthy patient subjects were each given a single, 1-mg lorazepam tablet. Urine samples from all patient subjects were collected at 12 intervals (0-2, 2-5, 5-8, 8-11, 11-14, 14-24, 24-26, 26-29, 29-32, 32-35, 35-38, and 38-48 hours). An aliquot from each urine collection was screened using cloned enzyme donor immunoassay (CEDIA), enzyme-multiplied immunoassay technique (EMIT) II, EMIT dau, and fluorescence polarization immunoassay (FPIA) without and with hydrolysis using beta-glucuronidase. Using a 200 ng/mL calibrator cut-off, none of the four immunoassays gave a positive response before hydrolyzation of the urine samples. For offline hydrolysis using Helix pomatia beta-glucuronidase, 35, 3, 0, and 4 of 48 urine samples gave positive responses on the previously listed immunoassays. The CEDIA method also gave 32 of 48 positive responses for online hydrolysis using Escherichia coli beta-glucuronidase. Online hydrolysis can be conveniently automated by including the beta-glucuronidase in the first of the two reagents combined with the urine sample.

Use and abuse of the benzodiazepines

Since chlordiazepoxide was introduced in 1961, the benzodiazepines have had many important roles in the pharmacotherapy of various disorders. This drug class for the central nervous system has been considered one of the safest in use for 35 years, especially when the benzodiazepines are compared with the barbiturates they often replaced. The objective of this article is to provide an update on the availability and distribution of benzodiazepines around the world and to discuss their most common clinical applications. Adverse effects of benzodiazepines, observed after long-term therapeutic use and after overdoses, are also presented. Triazolam is discussed because this benzodiazepine was removed from the market by regulatory authorities in the United Kingdom in 1991. Benzodiazepines will continue to have an important role in clinical medicine. Their clinical use, however, should be monitored more closely because of the greater awareness of their adverse effects after long-term use and because of the potential for misuse and abuse.

CEDIA dau Benzodiazepine screening assay: a reformulation

The CEDIA dau Benzodiazepine assay has been reformulated to include online hydrolysis of urinary benzodiazepine glucuronide conjugates. The new antibody possesses enhanced cross-reactivities toward the low-dose benzodiazepines, which are excreted at low urinary drug-metabolite concentrations. The screening method was evaluated using lorazepam as the probe benzodiazepine. Four subjects each consumed a 1-mg lorazepam tablet. Sequential urine voids over the same time intervals were collected for the next 48 h. Twelve postdose urine samples were collected from each subject. Positive results were obtained from 5-24 h to 2-35 h using a 200-ng/mL nitrazepam calibration cutoff. There was no practical difference between hydrolyzing online with the supplied E. coli beta-glucuronidase or offline with Helix pomatia beta-glucuronidase purchased separately. Without hydrolysis, all urine samples tested negative. The cross-reactivities of lorazepam in terms of nitrazepam calibration equivalents, varied from 108 to 178% for lorazepam concentrations between 50 and 2500 ng/mL. Lorazepam glucuronide gave cross-reactivities (expressed as lorazepam base) between 72 and 136% using the online hydrolysis procedure with E. coli beta-glucuronidase. Offline hydrolysis with Helix pomatia gave cross-reactivities between 84 and 134%. Without hydrolysis, lorazepam glucuronide gave less than 4% cross-reactivity in the assay.

Improved cross-reactivity to alpha OH triazolam in the BMC CEDIA DAU urine benzodiazepine assay

Immunoassays designed to detect use of older benzodiazepines such as oxazepam or diazepam often cannot detect triazolam use because of the low doses of triazolam administered, rapid biotransformation to metabolites with poor cross-reactivities, and the small amount of alpha OH triazolam glucuronide excreted in the urine. Previous studies have demonstrated that certain immunoassays have high cross-reactivity to alpha OH triazolam but are unable to detect therapeutic triazolam use in urine. The objectives of this study were to characterize the immunoreactivity toward alpha OH triazolam in the reformulated cloned enzyme donor immunoassay (CEDIA) drug abuse urine benzodiazepine assay and to measure the immunoreactivity of urine specimens from subjects who were administered single oral doses of triazolam. Alpha OH triazolam standards were prepared in drug-free urine and the new CEDIA assay gave a positive result at concentrations from 100 to 200 ng/ml, which indicates an eight-fold improvement in CEDIA cross-reactivity to alpha OH triazolam standards in the reformulated CEDIA assay. With a 200 ng/ml cut-off, 4/30 of the urine specimens screened positive for benzodiazepines without enzymatic hydrolysis and 6/30 after enzymatic hydrolysis. When using an in-house 100 ng/ml nitrazepam cut-off calibrator, 10/30 urine specimens were positive in the reformulated CEDIA assay without hydrolysis and 22/30 were positive with enzymatic hydrolysis before screening.

Mitochondrial membrane potential and nuclear changes in apoptosis caused by serum and nerve growth factor withdrawal: time course and modification by (-)-deprenyl

Studies in non-neural cells have suggested that a fall in mitochondrial membrane potential (DeltaPsiM) is one of the earliest events in apoptosis. It is not known whether neural apoptosis caused by nerve growth factor (NGF) and serum withdrawal involves a decrease in DeltaPsiM. We used epifluorescence and laser confocal microscopy with the mitochondrial potentiometric dyes chloromethyl-tetramethylrosamine methyl ester and 5,5',6, 6'-tetrachloro-1,1',3,3'-tetraethybenzimidazol carbocyanine iodide to estimate DeltaPsiM. PC12 cells were differentiated in media containing serum and NGF for 6 d before withdrawal of trophic support. After washing, the cells were incubated with media containing serum and NGF (M/S+N), media without serum and NGF, or media with the "trophic-like" monoamine oxidase B inhibitor, (-)-deprenyl. Mitochondria in cells without trophic support underwent a progressive shift to lower DeltaPsiM values that was significant by 3 hr after washing. The percentages of cells with nuclear chromatin condensation or nuclear DNA fragmentation were not significantly increased above those for cells in M/S+N until 6 hr after washing. Replacement of cells into M/S+N or treatment with (-)-deprenyl markedly reduced the proportion of mitochondria with decreased DeltaPsiM. Measurements of cytoplasmic peroxyl radical levels with 2',7'-dihydrodichlorofluorescein fluorescence and intramitochondrial Ca2+ with dihydro-rhodamine-2-acetylmethyl ester indicated that cytoplasmic peroxyl radical levels were not increased until after 6 hr, whereas increases in intramitochondrial Ca2+ paralleled the decreases in DeltaPsiM. (-)-Deprenyl appeared to alter the relationship between intramitochondrial Ca2+ levels and DeltaPsiM, possibly through its reported capacity to increase the synthesis of proteins such as BCL-2.

Oxaprozin cross-reactivity in three commercial immunoassays for benzodiazepines in urine

Immunoassay methods are commonly used to screen for drugs of abuse and some prescription drug classes as part of drug-testing programs in clinical and forensic toxicology. Oxaprozin (Daypro) is a new nonsteroidal anti-inflammatory drug that is widely prescribed in North America and has been reported to cross-react for benzodiazepines in several different immunoassay methods. The first objective of this study was to characterize the immunoreactivity of oxaprozin standards over a wide concentration range when analyzed by the EMIT dau, Abbott FPIA, and BMC CEDIA urine benzodiazepine assays. The second objective was to measure the immunoreactivity of urine specimens obtained from 12 subjects after receiving a single oral dose (1200 mg) of oxaprozin. Urine oxaprozin standards were prepared in drug-free urine at seven concentrations ranging from 500 to 100,000 ng/mL. The standards gave presumptive positive benzodiazepine results between 5000 and 10,000 ng/mL (EMIT dau) and approximately 10,000 ng/mL (FPIA, CEDIA). With a 200-ng/mL cutoff for benzodiazepines in these assays, all 36 urine specimens collected from the 12 subjects gave positive results by EMIT and CEDIA, and 35 of 36 urine specimens were positive by FPIA. It was concluded that presumptive positive benzodiazepine results by these immunoassays may be due to the presence of oxaprozin or oxaprozin metabolites. It is recommended that all positive immunoassay screening tests for benzodiazepines be confirmed by another technique based upon a different principle of analysis.

Urine drug testing for social service agencies in Nova Scotia, Canada

In Nova Scotia Canada, governmental authorities expressed concern in the late 1980s about the adverse effects of drug use by parents on the welfare of their children. Since 1991, parents with a history of drug abuse may be required to submit to urine drug and alcohol testing when ordered by the Family Courts of this province. The objective of this paper is to present this drug testing program and the results of drug testing on 125 clients from 1994-1996. Urine specimens were collected in the parents' residence by a nurse and transferred directly to the laboratory by the collector or a courier. Specimens were screened by immunoassay and TLC followed by GC-MS confirmation. Results were sent directly to the social worker. In the 3,613 urine specimens analyzed, 50.2% of specimens were negative, 45.6% were positive for one or more drug/metabolite and 4.2% of specimens were dilute (creatinine < 25 mg/dL). The distribution of positive results were: cannabinoids (11.5%), cocaine metabolite (5.0%), benzodiazepines (14.5%), codeine/morphine (7.1%), codeine (6.6%), diphenhydramine (2.2%) and ethyl alcohol (1.6%). Drug testing has been considered a success by these agencies since testing provides an objective indication of recent drug use and the overall prevalence of drug use in this drug abusing population has reduced from 100% to < 50%.

Comparative evaluation of five immunoassays for the analysis of alprazolam and triazolam metabolites in urine: effect of lowering the screening and GC-MS cut-off values

This study included evaluation of five commercially available immunoassays for the detection of alprazolam and triazolam metabolites in urine following single oral doses of these drugs. The products investigated were the EMIT d.a.u. assay, EMIT II assay, Abbott TDx (FPIA) assay, Bio Site TRIAGE device, and the Boehringer Mannheim/Microgenics CEDIA assay for urinary benzodiazepines. Urine specimens were also analyzed quantitatively by gas chromatography-mass spectrometry. Percent cross-reactivity was assessed by analysis of drug free urine containing drug standards at concentrations ranging from 100 to 10,000 ng/mL. The drug standards analyzed were alpha-OH-alprazolam, alpha-OH-triazolam, and alpha-OH-alprazolam glucuronide. The effect of lowering the screening cut-off value to 100 ng/mL, lowering the confirmation cut-off value to 50 and 25 ng/mL and the use of beta-glucuronidase hydrolysis prior to analysis was also studied. Lowering the screening cut-off value and using enzymatic hydrolysis prior to screening increased the positive detection rate for benzodiazepines with the EMIT d.a.u. assay and fluorescence polarization immunoassay (FPIA). The TRIAGE device gave the lowest percent cross-reactivity in the analysis of the drug standards and gave negative results in all urine specimens analyzed following ingestion of alprazolam and triazolam.

New drugs for the treatment of epilepsy

OBJECTIVES

This article will review current data on the metabolism, interactions, methods of analysis, and adverse effects observed with the use of new anticonvulsant drugs. The role of the laboratory in the provision of therapeutic drug monitoring for these drugs is discussed.

CONCLUSION

Certain of the newer anticonvulsant drugs require therapeutic drug monitoring for their optimal use in the treatment of epileptic seizures. The requirement for therapeutic drug monitoring has not been established for some of these drugs. Many of the newer anticonvulsant drugs, including lamotrigine, felbamate, vigabatrin, and zonisamide, interact clinically with established drugs, such as phenytoin, phenobarbital, carbamazepine, and valproic acid. Introduction of these new drugs will result in the need for more frequent monitoring of the established drugs during polytherapy. The need for a drug-monitoring service for anticonvulsant drugs overall will continue, due to the frequency of drug interactions, the incidence of adverse effects, and concerns about compliance with the dosing regimen in these patients.

Rapid detection and enumeration of Salmonella in chicken carcass rinses using filtration, enrichment and colony blot immunoassay

A strategy was developed for 24-h detection and enumeration of Salmonella spp. on processed chicken carcasses. Carcasses were rinsed with saline and the rinses spiked with known numbers of serogroup B, C, D or E Salmonella. The total rinse volume was passed through two filter units of decreasing pore size. These removed most of the extraneous material while permitting rapid passage of more than 77% of the Salmonella. At least 100 ml of the filtrate was passed through a third filter unit containing a nitrocellulose capture membrane. Captured bacteria were selectively enriched by incubating the nitrocellulose membrane on filter pads soaked in Rappaport-Vassiliadis broth and then on pads soaked in brilliant green broth containing sulfadiazine and novobiocin. A colony blot immunoassay using two anti-Salmonella monoclonal antibodies was used to identify and enumerate the captured Salmonella. As few as five Salmonella colony forming units per carcass rinse could be detected. An evaluation of this system with 24 field samples indicated that the specificity was comparable to and the sensitivity higher than that of standard culture procedures.

Evaluation of the Abbott TDx serum benzodiazepine immunoassay for the analysis of lorazepam, adinazolam, and N-desmethyladinazolam

This study involved the evaluation of the Abbott TDx serum benzodiazepine assay, a fluorescence polarization immunoassay (FPIA), for the detection of lorazepam, adinazolam, and N-desmethyladinazolam in serum. Precision of the assay was determined by using three control serums containing 75, 300, and 700 ng/mL nordiazepam. Between-run precision studies (N = 22) gave mean values of 76, 306, and 690 ng/mL with coefficients of variation of 6.5, 3.3, and 5.7%, respectively. Percent cross-reactivity of serum lorazepam standards (35-500 ng/mL) ranged from 29 to 69%. The cross-reactivity of serum adinazolam ranged from 40 to 47% between 50 and 150 ng/mL and from 38 to 55% for N-desmethyladinazolam between 50 and 250 ng/mL. Serum specimens (48) collected from individuals known to be receiving lorazepam were analyzed. Twenty-two specimens were positive for benzodiazepines. Serum specimens were collected from 0.25 to 24 h after administering a 15-mg oral dose of adinazolam to six volunteers. The FPIA results were compared with combined high-performance liquid chromatographic (HPLC) results for adinazolam and N-desmethyladinazolam. The FPIA method did not detect benzodiazepines at 0.25 h after administration of adinazolam but did detect benzodiazepines from 0.5 to 24 h after administration. The correlation between HPLC (N-desmethyladinazolam) and FPIA results by regression analysis gave the following: y = 0.937x + 4.449, r = 0.98, n = 15. It was concluded that the Abbott FPIA assay for benzodiazepines can detect lorazepam when prescribed in therapeutic doses and when present at greater than 25 ng/mL and can semiquantitatively detect adinazolam or N-desmethyladinazolam or both when present at concentrations greater than 50 ng/mL.

Analysis of diethyltoluamide (DEET) following intentional oral ingestion of Muscol

N,N-Diethyl-m-toluamide (DEET) is an effective component of several insect repellent products. A 19-year-old woman was admitted to the emergency department following ingestion of 15-25 mL 95% diethyltoluamide (Muscol). Serum and urine toxicology screening tests were negative except for detection of DEET. DEET was qualitatively identified and quantitated by gas chromatography-mass spectrometry. Concentrations of DEET based on selected ion monitoring (ion at m/z 119) were 63.0, 17.2, 1.9, and less than 0.2 mg/L in serum specimens collected at 2, 5, 24, and 48 h following ingestion, respectively. Serial monitoring of DEET concentrations and the cardiac abnormalities observed in this case following oral ingestion were not reported previously.

Lamotrigine analysis in serum by high-performance liquid chromatography

Lamotrigine is an anticonvulsant drug soon to be introduced to the North American market. It is chemically unrelated to any currently available antiepileptic drug. The objective of this study was to develop a quantitative high-performance liquid chromatography assay for lamotrigine in serum. Lamotrigine was extracted from serum at alkaline pH into ethyl acetate after addition of the internal standard (BW725C78). After mixing, the organic layer was evaporated to dryness before dissolving the residue in methanol for isocratic separation on a RP-8 column (5 microns) with a mobile phase of water/0.5 M phosphate buffer at pH 6.5/acetonitrile (790/10/200) with eluant monitoring at 306 nm. Calibration was performed with five serum standards (2-32 microM and recovery averaged 88% at 25 microM. Between-run precision was 4.1 and 2.5% C.V. at 13.6 and 31.6 microM, respectively. At room temperature, lamotrigine was stable for a minimum of 7 days. Interference studies were performed on serum specimens containing commonly monitored drugs. The only potentially interfering drug was carbamazepine, which elutes 2.5 times longer than lamotrigine. We conclude that this is a reliable method for quantitation of lamotrigine in serum.

Simple extraction of Campylobacter lipopolysaccharide and protein antigens and production of their antibodies in egg yolk

Antigens were heat extracted from Campylobacter jejuni (LI04) and C. coli (LI020) in the presence of ethylenediaminetetraacetate (EDTA) and were recovered in the supernatant of a low-speed centrifugation. The method is simpler, safer and more efficient in extracting lipopolysaccharide (LPS) antigens than the hot phenol method. The extracted antigens (LPS plus several proteins) elicited production of antigen-specific antibodies in the egg yolk of immunized hens. Antibodies purified by polyethyleneglycol fractionation were used to detect antigens fractionated on SDS polyacrylamide gel electrophoresis.

Modes of inhibition of foodborne non-Salmonella bacteria by selenite cystine selective broth

Various cell densities of six common foodborne non-Salmonella bacteria were exposed to selenite cystine (SC) Salmonella selective medium. The insensitivity of Pseudomonas aeruginosa and Proteus vulgaris to SC was confirmed. Selenite cystine selective medium was effective against the sensitive bacteria up to certain cell densities, beyond which the bacteria survived. As judged from the minimum cell number required for survival in SC, Staphylococcus aureus was the most sensitive to SC, followed by Bacillus cereus, Escherichia coli and Citrobacter freundii. When sensitive bacteria were grown in SC, they enriched resistant variants which exhibited no or reduced sensitivity to SC. The change in density of sensitive cells after exposure to SC suggested that bacterial sensitivity to SC depended on the efficiency of killing and growth inhibition by SC as well as the fraction of resistant variants in the bacterial population. Since Salmonella samples generally contain unknown numbers and types of sensitive bacteria, it is difficult to predict the effectiveness of their selective inhibition by SC.

Urinary screening for adinazolam and its major metabolites by the Emit d.a.u. and FPIA benzodiazepine assays with confirmation by HPLC

Adinazolam is a triazolobenzodiazepine, currently under clinical investigation, that possesses antidepressant and anxiolytic activity. It has a short half-life (less than 3 h), and less than 2% of an oral dose is excreted unchanged. The major urinary metabolite is N-desmethyladinazolam, and minor metabolites are estazolam and alpha-OH-alprazolam. The objective of this study was to characterize the reactivity of adinazolam, N-desmethyladinazolam, and estazolam in the Emit d.a.u. benzodiazepine assay and the Abbott TDx urine (FPIA) benzodiazepine assay. N-desmethyladinazolam and estazolam gave an equivalent response to the Emit cutoff calibrator (300 ng/mL) at 100-200 ng/mL, and adinazolam gave an equivalent response at 200 ng/mL. By FPIA, N-desmethyladinazolam and adinazolam had equivalent net polarization values as the 300-ng/mL low control at 500-1000 ng/mL, and estazolam gave a positive response at 300 ng/mL. Six volunteers received single oral doses of 10, 30, and 50 mg of adinazolam. Urine specimens (N = 7) were collected from 0 to 36 h post-administration. By Emit, all urine specimens at all doses were positive from 2 to 36 h, and all FPIA analyzed specimens were positive from 2 to 24 h. Confirmation testing was performed by HPLC by analyzing for N-desmethyladinazolam. All urine specimens were confirmed positive for N-desmethyladinazolam (greater than 200 ng/mL) except for the blank specimens (time = 0) and 7 of 18 specimens collected 36 h post-administration. In conclusion, both immunoassay screening assays are acceptable for detecting the presence of adinazolam in human urine for up to 24 h after a single oral dose of 10-50 mg.

The use of antiepileptic drug levels in children: a survey of Canadian pediatric neurologists

There are 60 pediatric neurologists in Canada. Replies were received from 56 in response to a survey regarding the use and perceived value of antiepileptic drug (AED) levels. AED levels are frequently ordered and influence clinical care. There were, however, discrepancies among pediatric neurologists regarding the upper and lower limits of the "therapeutic ranges" and the clinical application of levels. We suggest that both the value and use of AED levels needs further study.