COVID-19 infection and maternal morbidity in critical care units in Scotland: a national cohort study

BACKGROUND

Previous research has shown that, in comparison with non-pregnant women of reproductive age, pregnant women with COVID-19 are more likely to be admitted to critical care, receive invasive ventilation, and die. At present there are limited data in relation to outcomes and healthcare utilisation following hospital discharge of pregnant and recently pregnant women admitted to critical care.

METHODS

A national cohort study of pregnant and recently pregnant women who were admitted to critical care in Scotland with confirmed or suspected COVID-19. We examined hospital outcomes as well as hospital re-admission rates.

RESULTS

Between March 2020 and March 2022, 75 pregnant or recently pregnant women with laboratory-confirmed COVID-19 were admitted to 24 Intensive Care Units across Scotland. Almost two thirds (n=49, 65%) were from the most deprived socio-economic areas. Complete 90-day acute hospital re-admission data were available for 74 (99%) patients. Nine (12%) women required an emergency non-obstetric hospital re-admission within 90 days. Less than 5% of the cohort had received any form of vaccination.

CONCLUSIONS

This national cohort study has demonstrated that pregnant or recently pregnant women admitted to critical care with COVID-19 were more likely to reside in areas of socio-economic deprivation, and fewer than 5% of the cohort had received any form of vaccination. More targeted public health campaigning across the socio-economic gradient is urgently required.

Left ventricular dysfunction, heart failure, and mortality risk factors in de novo pacemaker recipients and those requiring pacemaker generator replacement

Background

Pacing the right ventricle (RV) can lead to adverse remodelling of the left ventricle (LV), LV dysfunction, increased risk of heart failure hospitalisation (HFH) and mortality. Despite RV pacing avoidance programming becoming commonplace, pacemaker patients remain at risk of pacing-induced cardiomyopathy. New pacing strategies and cardiac resynchronisation therapy are available therapeutic options, but it is unclear which patients should be targeted, and when.

Purpose

This study examined the effects of RV pacing on LV function, the risk of heart failure requiring hospitalisation and all-cause mortality in patients during the first 12 months of pacemaker therapy, compared to those at pacemaker generator replacement (PGR).

Methods

Data were obtained from a cohort of patients who underwent de novo pacemaker implantation between 2014 and 2017, and patients requiring PGR between 2008 and 2011 at a single tertiary UK hospital, with follow-up from 12 months. Clinical, echocardiographic, and pacemaker variables, medication, and past medical history data were collected. Predictors of a combined endpoint of all-cause mortality or HFH were assessed using cox-regression analysis, with predictors of impaired LV function analysed using multivariable regression analysis.

Results

514 newly implanted (NI) patients (mean age, 75 years; 66% male) were recruited, and 491 patients (mean age, 76 years; 56% male) requiring PGR. After a mean follow up of 887 days, 79 NI patients (16%) were deceased (n=27) or had been hospitalised for HF (n=52), whereas after a mean follow up of 668 days, 56 patients after PGR (12%) were deceased (n=34) or had been hospitalised (n=22) for HF. After 12 months of pacemaker therapy, 182 (35%) NI patients had a LV ejection fraction (LVEF) <50%, which had a higher incidence at PGR of 197 (40%). Age was the only significant predictor of mortality or HFH for both NI and PGR (hazard ratio (HR), 1.068; 95% confidence interval (CI), 1.039 to 1.098; p<0.001 vs 1.035; 95% CI, 1.007 to 1.064; p=0.014), respectively). Univariate analysis revealed baseline LVEF (2.439; 95 percent CI, 1.279 to 4.659; p=0.007), RV pacing burden, medication and blood chemistry were significant predictors of the combined outcome at PGR but not at NI (Table 2). Multivariable analysis of predictors of LV impairment (<50% LVEF) showed history of MI (odds ratio (OR), 0.47; 95% CI, 0.29 to 0.78; p=0.003), RV pacing burden (1.01; 95% CI, 1.01 to 1.02; p<0.001) and creatinine (1.06; 95% CI, 1.02 to 1.10; p=0.004) were independently associated in both cohorts.

Conclusions

Our data suggest that there remains a similar subgroup of people from initial implantation to PGR at risk of LV impairment that might benefit from medication optimisation or novel pacing strategies. Further research is required to better identifying these people to direct more complex therapies to those with the most to gain.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The research is supported by a National Institute for Health Research (NIHR) clinician scientist fellowship (NIHRCS-2012-032). The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health. This research was supported by the NIHR Leeds Clinical Research Facility.

Occupational health screening during Gurkha Central Selection: a retrospective cohort study

Objective

The selection process to the British Army’s Brigade of Gurkhas is rigorous, demanding and competitive. The ethos of recruitment to the Gurkhas is grounded in an overarching tenant: that selection is free, fair and transparent. The aim of this study was to retrospectively review reasons for potential recruits (PRs) to be deemed medically unsuitable or deferred suitability on medical grounds for selection to the Brigade of Gurkhas.

Methods

A retrospective review was conducted by extracted data from published post-exercise reports for the past four years to ascertain numbers of PRs deemed medically fit, medically unsuitable or deferred suitability on medical grounds. The International Classification of Disease version 11 (ICD-11) codes were retrospectively assigned to code medical reasons for non-progression. Rates of medical non-progression were compared by year.

Results

A total of 3154 PRs were analysed between 2018 and 2021. There was no significant difference between PRs deemed medically fit and those deemed medically suitable or deferred on medical grounds over the study period (p=0.351). There was a significant difference in the ratio of PRs deferred on medical grounds and those deemed medically unsuitable over the study period (p<0.05).

Conclusion

Selection to the Gurkhas is extremely competitive. These data demonstrate that, overall, reasons for medical deferral or unsuitability have remained constant despite the impact of a global pandemic. These data reinforce the central tenant of Gurkha selection; that it continues to be free, fair, and transparent.

The changing epidemiology of radial head replacement over a 22-year period in Scotland

BACKGROUND

Radial head replacement is used to confer joint stability in the management of acute unstable elbow fractures and dislocations associated with instability. We determined the annual incidence of radial head replacement over a 22-year period in a defined population.

MATERIALS AND METHODS

Hospital episode statistics were collected prospectively at a national level. This database was retrospectively examined to determine the annual incidence of radial head replacement over the study period in adults over 16 years of age.

RESULTS

A total of 615 radial head replacements were performed over the 22 years studied. The overall incidence was 0.65/100,000/year (95% confidence interval, CI, 0.50-0.71). The average adult population during the period was 4,270,593. There was a steady and statistically significant increase in the incidence of radial head replacement over the study period (r ² = 0.816; p < 0.0001). This incidence was significantly greater in women than men (odds ratio 1.46, 95% CI 1.25-1.72; p < 0.001). The peak incidence in men was 0.87/100,000 population/year in the fifth decade of life while in women the peak incidence was in the seventh decade of life (1.38/100,000 population/year).

CONCLUSION

The incidence of radial head replacement has increased steadily over 22 years. We hypothesise that this represents an evolving understanding of the role of radial head replacement in acute trauma in the context of emerging literature during the study period.

Predictors of death and new disability after critical illness: a multicentre prospective cohort study

PURPOSE

This study aimed to determine the prevalence and predictors of death or new disability following critical illness.

METHODS

Prospective, multicentre cohort study conducted in six metropolitan intensive care units (ICU). Participants were adults admitted to the ICU who received more than 24 h of mechanical ventilation. The primary outcome was death or new disability at 6 months, with new disability defined by a 10% increase in the WHODAS 2.0.

RESULTS

Of 628 patients with the primary outcome available (median age of 62 [49-71] years, 379 [61.0%] had a medical admission and 370 (58.9%) died or developed new disability by 6 months. Independent predictors of death or new disability included age [OR 1.02 (1.01-1.03), P = 0.001], higher severity of illness (APACHE III) [OR 1.02 (1.01-1.03), P < 0.001] and admission diagnosis. Compared to patients with a surgical admission diagnosis, patients with a cardiac arrest [OR (95% CI) 4.06 (1.89-8.68), P < 0.001], sepsis [OR (95% CI) 2.43 (1.32-4.47), P = 0.004], or trauma [OR (95% CI) 6.24 (3.07-12.71), P < 0.001] diagnosis had higher odds of death or new disability, while patients with a lung transplant [OR (95% CI) 0.21 (0.07-0.58), P = 0.003] diagnosis had lower odds. A model including these three variables had good calibration (Brier score 0.20) and acceptable discriminative power with an area under the receiver operating characteristic curve of 0.76 (95% CI 0.72-0.80).

CONCLUSION

Less than half of all patients mechanically ventilated for more than 24 h were alive and free of new disability at 6 months after admission to ICU. A model including age, illness severity and admission diagnosis has acceptable discriminative ability to predict death or new disability at 6 months.

Detrimental immediate and long-term clinical effects of right ventricular pacing in patients with myocardial fibrosis

Funding Acknowledgements

Type of funding sources: None.

Background

Long-term right ventricular (RV) pacing leads to heart failure or a decline in left ventricular (LV) function in up to a fifth of patients.

Objectives

We aimed to establish whether patients with focal fibrosis detected on late gadolinium enhancement cardiovascular magnetic resonance (CMR) have deterioration in LV function after RV pacing.

Methods

We recruited 110 patients (84 in final analysis) into two observational CMR studies. Patients (n = 34) with a dual chamber device and preserved atrioventricular (AV) conduction underwent CMR in two asynchronous pacing modes (AOO & DOO) to compare intrinsic conduction with RV pacing. Patients (n = 50) with high-grade AV block underwent CMR before and 6 months after pacemaker implantation to investigate the long-term effects of RV pacing.

Results: The three key findings were

1) Initiation of RV pacing in patients with fibrosis, compared to those without, was associated with greater immediate changes in both LV end-systolic volume index (LVESVi) (5.3 ± 3.5 vs 2.1 ± 2.4 mL/m2; p &lt; 0.01) and LV ejection fraction (LVEF) (-5.7 ± 3.4% vs -3.2 ± 2.6%; p = 0.02); 2) Long-term RV pacing in patients with fibrosis, compared to those without, was associated with greater changes in LVESVi (8.0 ± 10.4 vs -0.6 ± 7.3 mL/m2; p = 0.008) and LVEF (-12.3 ± 7.9 vs -6.7 ± 6.2%; p = 0.012); 3) Patients with fibrosis did not experience an improvement in quality of life, biomarkers or functional class after pacemaker implantation.

Conclusions

Fibrosis detected on CMR is associated with immediate and long-term deterioration in LV function following RV pacing and could be used to identify those at risk of heart failure prior to pacemaker implantation.

Characteristics before and after pacing Study 1 No fibrosis (n = 16) Fibrosis (n = 18) AOO DOO p-value AOO DOO p-value LVEDVi - mL/m&sup2; 66 ± 13 66 ± 12 0.67 78 ± 14 79 ± 13 0.34 LVESVi - mL/m&sup2; 30 ± 10 32 ± 9 0.003 38 ± 11 43 ± 12 &lt;0.001 LVEF - % 56 ± 6 53 ± 5 &lt;0.001 52 ± 8 47 ± 9 &lt;0.001 Mechanical Dyssynchrony index - ms 61 ± 17 71 ± 25 0.07 81 ± 18 89 ± 21 0.04 Study 2 No fibrosis (n = 19) Fibrosis (n = 31) Pre-PPM Post-PPM p-value Pre-PPM Post-PPM p-value LVEDVi -mL/m&sup2; 88 ± 21 73 ± 14 &lt;0.001 90 ± 18 83 ± 21 0.007 LVESVi -mL/m&sup2; 35 ± 9 34 ± 9 0.71 41 ± 14 49 ± 21 0.001 LVEF - % 60 ± 5 54 ± 7 &lt;0.001 56 ± 8 43 ± 12 &lt;0.001 Mechanical Dyssynchrony index - ms 70 ± 29 81 ± 22 0.15 84 ± 30 98 ± 31 0.03 Abstract Figure. Mechanism for heart failure after pacing

Partial normalisation of cardiac mechanics with active CRT in patients with chronic failure: a novel application of 3.0T CMR

Introduction

Cardiac resynchronisation therapy (CRT) is a routine treatment for chronic heart failure (CHF) with reduced ejection fraction and conduction delay to improve prognosis. Cardiac mechanics in patients with CHF are believed to be altered from controls based on invasive and echocardiographic based data. Technological advancements in cardiac magnetic resonance (CMR) and devices enable investigation of the cardiac response to CRT over a range of heart rates.

Methods

Patients with a CRT-D device were enrolled from heart failure clinics at Leeds General Infirmary, UK. After a MRI safety assessment, a baseline device check was conducted by a cardiac physiologist. Left ventricular (LV) volumes and systolic BP were measured at baseline and heart rates of 75, 90, 100, 115, 125, and 140 (randomised order) with CRT active and intrinsic conduction. All scans were conducted using a 3.0 T Siemens Prisma MRI scanner. Analysis of the scans used commercially available software. LV contractility was derived as a ratio of the LV end systolic volume and systolic BP. A post scan device interrogation was conducted to assess for scanning safety. Control participants with a 3.0T MR-conditional dual chamber pacemakers completed a similar protocol.

Results

Scanning was conducted in 17 CRT patients and 13 controls with a pre and post device and lead interrogation. No patient experienced symptoms related to scanning or device failure. The mean LV ejection fraction at baseline in the CRT cohort was 33.7±12.9%. Left ventricular ejection fraction fell across both cohorts as paced heart rate increased with reduced deterioration in control patients and those with CRT active. Peak LV cardiac output was significantly higher during active CRT (p&lt;0.05). LV contractility was relatively static with CRT disabled (r2=0.13, p=0.38) and improved with CRT active (r2=0.91, p=0.01) and in controls (r2=0.74, p=0.01). Peak LV strain occurred at 100bpm during active CRT and in control patients whereas CRT disabled resulted in earlier deterioration.

Conclusion

We have demonstrated improvements in cardiac output and contractility consequent to active CRT using 3.0T CMR and subsequently validated via strain analysis. CRT appears to partially normalise cardiac mechanics across the range of heart rates studied. Further work is required to explore this phenomenon on a cellular or metabolic level.

Funding Acknowledgement

Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): AK is supported by an unconditional grant provided by Medtronic

P1236Revealing cardiac mechanics with CMR whilst CRT is active: the first step

Introduction

Cardiac resynchronisation therapy (CRT) is a routine treatment for heart failure with reduced ejection fraction and conduction delay to improve symptoms and prognosis. Technological advancements both in cardiac magnetic resonance (CMR) and devices (MRI-conditional modes) now enable investigation of the haemodynamic response to CRT over a range of heart rates.

Methods

Patients with a CRT-D device were enrolled from heart failure clinics at a single tertiary centre. A complete device system assessment and baseline device check was conducted to ensure MRI compatibility and suitability. Left ventricular (LV) volumes and systolic blood pressure were measured at baseline and heart rates of 75, 90, 100, 115, 125, and 140 bpm (randomised order) with CRT active and intrinsic conduction (AOO). MRI conditional mode parameters were replicated through standard parameter modification to ensure biventricular pacing during CRT active scans. All scans were conducted using a 3.0 T Siemens Prisma MRI scanner with analysis on commercially available software. Contractility was derived from the systolic blood pressure and left ventricular end systolic volume. A post scan device and lead assessment was conducted to assess for scanning safety.

Results

Scanning was conducted in 22 patients (safety cohort). Post scan battery voltage reduced by 2.9±1.0%. Mean change in atrial, right ventricular and left ventricular lead impedance was 0.5±0.06%, 3.0±0.04% and −1.7±0.05% respectively. Mean change in atrial, right ventricular and left ventricular pacing threshold was 0.0±0.3%, 8.3±0.3% and 5.6±0.3%. No patient experienced symptoms related to scanning or device failure.

Preliminary data for patients with CRT on and off have been analysed (paired analysis cohort, n=8, 6 men). Mean age was 71.1±8.2, aetiology was primarily ischaemic (62.5%) with the remainder dilated cardiomyopathy. The mean LV ejection fraction at baseline was 29.4±12.9%. Biventricular pacing led to acute improvements in ejection fraction (p=0.005), left ventricular cardiac output (p<0.0001) and contractility (p=0.05) over the entire range of heart rates studied. We also noted an improvement in the force frequency relationship during biventricular pacing with a higher peak contractility (p=0.05), a higher heart rate at which this occurred (HR=130) and a generally up sloping relationship when compared with intrinsic conduction.

Conclusion

We have demonstrated for the first time, the mechanistic improvements in cardiac contractility consequent to CRT using CMR and also that MRI scans of conditional devices can be safe with CRT active.

Acknowledgement/Funding

Dr A Koshy is conducting a PhD supported by grant from Medtronic. Dr Klaus Witte has received honoraria from Medtronic

Mars Science Laboratory relative humidity observations: Initial results

The Mars Science Laboratory (MSL) made a successful landing at Gale crater early August 2012. MSL has an environmental instrument package called the Rover Environmental Monitoring Station (REMS) as a part of its scientific payload. REMS comprises instrumentation for the observation of atmospheric pressure, temperature of the air, ground temperature, wind speed and direction, relative humidity (REMS-H), and UV measurements. We concentrate on describing the REMS-H measurement performance and initial observations during the first 100 MSL sols as well as constraining the REMS-H results by comparing them with earlier observations and modeling results. The REMS-H device is based on polymeric capacitive humidity sensors developed by Vaisala Inc., and it makes use of transducer electronics section placed in the vicinity of the three humidity sensor heads. The humidity device is mounted on the REMS boom providing ventilation with the ambient atmosphere through a filter protecting the device from airborne dust. The final relative humidity results appear to be convincing and are aligned with earlier indirect observations of the total atmospheric precipitable water content. The water mixing ratio in the atmospheric surface layer appears to vary between 30 and 75 ppm. When assuming uniform mixing, the precipitable water content of the atmosphere is ranging from a few to six precipitable micrometers.

KEY POINTS

Atmospheric water mixing ratio at Gale crater varies from 30 to 140 ppmMSL relative humidity observation provides good dataHighest detected relative humidity reading during first MSL 100 sols is RH75.

Mars Science Laboratory relative humidity observations: Initial results

The Mars Science Laboratory (MSL) made a successful landing at Gale crater early August 2012. MSL has an environmental instrument package called the Rover Environmental Monitoring Station (REMS) as a part of its scientific payload. REMS comprises instrumentation for the observation of atmospheric pressure, temperature of the air, ground temperature, wind speed and direction, relative humidity (REMS-H), and UV measurements. We concentrate on describing the REMS-H measurement performance and initial observations during the first 100 MSL sols as well as constraining the REMS-H results by comparing them with earlier observations and modeling results. The REMS-H device is based on polymeric capacitive humidity sensors developed by Vaisala Inc., and it makes use of transducer electronics section placed in the vicinity of the three humidity sensor heads. The humidity device is mounted on the REMS boom providing ventilation with the ambient atmosphere through a filter protecting the device from airborne dust. The final relative humidity results appear to be convincing and are aligned with earlier indirect observations of the total atmospheric precipitable water content. The water mixing ratio in the atmospheric surface layer appears to vary between 30 and 75 ppm. When assuming uniform mixing, the precipitable water content of the atmosphere is ranging from a few to six precipitable micrometers.

KEY POINTS

Atmospheric water mixing ratio at Gale crater varies from 30 to 140 ppmMSL relative humidity observation provides good dataHighest detected relative humidity reading during first MSL 100 sols is RH75.

Clinical practice recommendations for bipolar disorder

OBJECTIVE

To provide clinically relevant evidence-based recommendations for the management of bipolar disorder in adults that are informative, easy to assimilate and facilitate clinical decision-making.

METHOD

A comprehensive literature review of over 500 articles was undertaken using electronic database search engines (e.g. MEDLINE, PsychINFO and Cochrane reviews). In addition articles, book chapters and other literature known to the authors were reviewed. The findings were then formulated into a set of recommendations that were developed by a multidisciplinary team of clinicians who routinely deal with mood disorders. These preliminary recommendations underwent extensive consultative review by a broader advisory panel that included experts in the field, clinical staff and patient representatives.

RESULTS

The clinical practice recommendations for bipolar disorder (bipolar CPR) summarise evidence-based treatments and provide a synopsis of recommendations relating to each phase of the illness. They are designed for clinical use and have therefore been presented succinctly in an innovative and engaging manner that is clear and informative.

CONCLUSION

These up-to-date recommendations provide an evidence-based framework that incorporates clinical wisdom and consideration of individual factors in the management of bipolar disorder. Further, the novel style and practical approach should promote their uptake and implementation.

Clinical practice recommendations for depression

OBJECTIVE

To provide clinically relevant evidence-based recommendations for the management of depression in adults that are informative, easy to assimilate and facilitate clinical decision making.

METHOD

A comprehensive literature review of over 500 articles was undertaken using electronic database search engines (e.g. MEDLINE, PsychINFO and Cochrane reviews). In addition articles, book chapters and other literature known to the authors were reviewed. The findings were then formulated into a set of recommendations that were developed by a multidisciplinary team of clinicians who routinely deal with mood disorders. The recommendations then underwent consultative review by a broader advisory panel that included experts in the field, clinical staff and patient representatives.

RESULTS

The clinical practice recommendations for depression (Depression CPR) summarize evidence-based treatments and provide a synopsis of recommendations relating to each phase of the illness. They are designed for clinical use and have therefore been presented succinctly in an innovative and engaging manner that is clear and informative.

CONCLUSION

These up-to-date recommendations provide an evidence-based framework that incorporates clinical wisdom and consideration of individual factors in the management of depression. Further, the novel style and practical approach should promote uptake and implementation.

Aldehyde oxidase is coamplified with the World's most common Culex mosquito insecticide resistance-associated esterases

The evolution and spread of insecticide resistance is an important factor in human disease prevention and crop protection. The mosquito Culex quinquefasciatus is the main vector of the disease filariasis and a member of a species complex which is a common biting nuisance worldwide. The common insecticide resistance mechanism in this species involves germline amplification of the esterases estalpha21 and estbeta21. This amplification has arisen once and rapidly spread worldwide. Less common and more variable resistance phenotypes involve coamplification of estalpha3 and estbeta1, or individual amplification of a single estbeta1, different alleles of the same estalpha and estbeta gene loci. Estalpha21 and estbeta21 are on the same large fragment of amplified DNA (amplicon) 2.7 kb apart. We have now shown that this amplicon contains another full-length gene immediately 5' of estalpha21 which codes for a molybdenum-containing hydroxylase, with highest homology to aldehyde oxidase (AO) from other organisms. The full-length putative AO gene is not present on the estalpha3/estbeta1 or estbeta1 amplicons, but multiple truncated 5' ends of this gene are present around the presumed estalpha3/estbeta1 amplicon breakpoint. Polymerase chain reaction (PCR) analysis of insecticide-susceptible genomic DNA demonstrated that a different allele of the putative AO gene in its non-amplified form is immediately 5' of estalpha. The 'AO' gene on the estalpha21/estbeta21 amplicon is expressed and resistant insects have greater AO activity. This AO activity is sensitive to inhibition by an aldehyde-containing herbicide and pesticide. This enzyme may confer a selective advantage to these insects in the presence of insecticide, as AO in mammals is believed to be important in the detoxification process of several environmental pollutants.

Three dimensional imaging of the Belousov-Zhabotinsky reaction using magnetic resonance

The combination of 3D magnetic resonance imaging data with polygon based computer graphic display software is ideally suited to the study of the Belousov-Zhabotinsky reaction in extended volumes. In this paper we present the first true three dimensional visualization of experimental data from the Belousov-Zhabotinsky reaction. The time evolution of a twisted scroll wave like isoconcentration surface and its organizing filament are demonstrated for the manganese-catalyzed B-Z mixture. These techniques extend the experimental study of the B-Z reaction as a class of pattern-forming systems to the third dimension. The limitations of the technique are discussed.

Further evidence of functional differentiation within biceps brachii

This study investigated whether the two heads of Biceps Brachii could be functionally differentiated during rapid supination movements with different degrees of elbow flexion, shoulder axial rotation and load. Surface electromyograms, recorded from the long and short heads of Biceps Brachii, were utilised to identify changes in the intensity of muscle contraction. Based upon an analysis of sixteen subjects, the results indicated that joint position (muscle length), but not load, significantly (p < 0.05) influenced the relationship between the contraction intensities of the two heads. Specifically, increasing the length of the Biceps Brachii promoted increased activation of the long head in relation to the short head in producing rapid supination motions. It was concluded that functional differentiation within the two heads of Biceps Brachii was present in motions involving its distal insertion.

Intracellular killing of Candida albicans by human neutrophils is potentiated by exposure to combinations of amphotericin B and 5-fluorocytosine

Combination treatment with amphotericin B and 5-fluorocytosine is synergistic and has become clinically useful in the treatment of various forms of systemic candidosis. The synergy between these two compounds may be explained in part by their combined effect on the interaction between fungal cells and host phagocytes. Pretreatment of Candida albicans for 2 h with either amphotericin B or 5-fluorocytosine or the two agents in combination did not inhibit or enhance phagocytosis by glass-adherent human neutrophils (P greater than 0.05). Intracellular killing of pretreated yeast cells was not influenced by antifungals alone (P greater than 0.05), but pretreatment of C. albicans with 5.0 mg l-1 amphotericin B + 10 l-1 5-fluorocytosine or 5.0 mg l-1 amphotericin B + 50 mg l-1 5-fluorocytosine significantly enhanced the ability of neutrophils to kill the number of viable yeast cells intracellularly (P less than 0.001).

Evaluation of an enzyme-linked immunosorbent assay for the detection of Corynebacterium pseudotuberculosis infection in sheep

Two enzyme-linked immunosorbent assays to measure antibody to the cell wall antigen (C-ELISA) and toxin antigen (T-ELISA) of C. pseudotuberculosis were evaluated on serum from 6 separate groups of sheep. For sheep naturally infected with C. pseudotuberculosis the sensitivity and specificity of the C-ELISA was 76% and 73% respectively and for the T-ELISA 67% and 77% respectively. For sheep slaughtered one year after artificial infection the sensitivity of both tests was greater than or equal to 83% and the specificity greater than or equal to 72%. For sheep slaughtered 4 months after artificial infection the specificity of both tests was less than 30% while the mean sensitivity was 85%. The C-ELISA in conjunction with the T-ELISA detected 92% of sheep with lung lesions.