Towards optimal use of antithrombotic therapy of people with cancer at the end of life: A research protocol for the development and implementation of the SERENITY shared decision support tool

BACKGROUND

Even though antithrombotic therapy has probably little or even negative effects on the well-being of people with cancer during their last year of life, deprescribing antithrombotic therapy at the end of life is rare in practice. It is often continued until death, possibly resulting in excess bleeding, an increased disease burden and higher healthcare costs.

METHODS

The SERENITY consortium comprises researchers and clinicians from eight European countries with specialties in different clinical fields, epidemiology and psychology. SERENITY will use a comprehensive approach combining a realist review, flash mob research, epidemiological studies, and qualitative interviews. The results of these studies will be used in a Delphi process to reach a consensus on the optimal design of the shared decision support tool. Next, the shared decision support tool will be tested in a randomised controlled trial. A targeted implementation and dissemination plan will be developed to enable the use of the SERENITY tool across Europe, as well as its incorporation in clinical guidelines and policies. The entire project is funded by Horizon Europe.

RESULTS

SERENITY will develop an information-driven shared decision support tool that will facilitate treatment decisions regarding the appropriate use of antithrombotic therapy in people with cancer at the end of life.

CONCLUSIONS

We aim to develop an intervention that guides the appropriate use of antithrombotic therapy, prevents bleeding complications, and saves healthcare costs. Hopefully, usage of the tool leads to enhanced empowerment and improved quality of life and treatment satisfaction of people with advanced cancer and their care givers.

SARS-CoV-2 antibody dynamics over time and risk factors associated with infection and long COVID-19 symptoms in large working environments

Factors influencing SARS-CoV-2 antibody dynamics, transmission, waning and long COVID-19 symptomatology are still not fully understood. In the Danish section of the Novo Nordisk Group, we performed a prospective seroepidemiological study during the first and second waves of the COVID-19 pandemic. All employees and their household members (>18 years) were invited to participate in a baseline (June-August 2020), 6-month follow-up (December 2020-January 2021), and 12-month follow-up (August 2021) sampling. In total, 18,614 accepted and provided at least one blood sample and completed a questionnaire regarding socioeconomic background, health status, previous SARS-CoV-2 infection, and persistent symptoms. Total antibody and specific IgM, IgG and IgA levels against recombinant receptor binding domain were tested. At baseline, the SARS-CoV-2-antibody seroprevalence was 3.9%. At the 6-month follow-up, the seroprevalence was 9.1%, while at the 12-month follow-up, the seroprevalence was 94.4% (after the vaccine rollout). Male sex and younger age (18-40 years) were significant risk factors for seropositivity. From baseline to the 6-month sampling, we observed a substantial waning of IgM, IgG and IgA levels (p<0.001), regardless of age, sex and initial antibody level. An increased antibody level was found in individuals infected prior to vaccination compared to vaccinated infection naïves (p<0.0001). Approximately a third of the seropositive individuals reported one or more persistent COVID-19 symptoms, with anosmia and/or ageusia (17.5%) and fatigue (15.3%) being the most prevalent. In conclusion, this study provides a comprehensive insight into SARS-CoV-2 antibody seroprevalence following infection and vaccination, waning, persistent COVID-19 symptomatology and risk factors for seropositivity in large working environments. This article is protected by copyright. All rights reserved.

Nationwide trends and projections of peripheral arterial disease among Danish adults

Background

Peripheral arterial disease (PAD) is a critical clinical and public health issue with a prevalence of &gt;10% worldwide among adults ≥50 years. Whether this occurrence has been increasing, decreasing or stable over time remains a matter of debate as contemporary population data are sparse and conflicting.

Purpose

To quantify changes in PAD incidence, prevalence, and mortality and provide projections for future prevalence development through 2050.

Methods

We conducted nationwide analyses of the entire Danish population aged ≥40 years from 2000 through 2018 to assess national trends in diagnosed PAD incidence, prevalence, and all-cause mortality, overall and by sex and age-groups. PAD was identified by primary or secondary in-hospital or outpatient clinic diagnoses, and incident cases comprised individuals whose preceding complete hospital history, potentially back to 1977, lacked a PAD diagnosis. Based on observed trends in incidence and PAD mortality between 2000–2018, and the projected future annual age distribution and population mortality obtained from Statistics Denmark, we projected the future prevalence of PAD through 2050.

Results

The population of Denmark aged 40–99 years between 2000 and 2018 included 4,508,932 individuals, among whom we identified 123,479 incident diagnoses of PAD during 51,4 million person-years of follow-up. The age- and sex-standardized incidence of PAD decreased from 2.70 per 1,000 person-years in 2000 to 1.79 in 2018 (incidence rate ratio 0.67, 95% confidence interval (CI) 0.65–0.70) (Figure 1). The incidence was approximately 20% higher in men than in women but the accentuation was similarly in both sexes. Concurrently, the overall prevalence of PAD in the Danish adult population increased from 0.8% to 1.7% (prevalence ratio 2.12, 95% CI 2.09–2.15). The prevalence rose considerably in the oldest age groups; in 2018 the prevalence was 5.8% in women and 8.0% in men aged ≥80 years. The age- and sex-standardized annual mortality among patients with PAD decreased from 9.9% in 2000 to 7.0% in 2018, representing a mortality ratio of 0.82 (95% CI 0.75–0.91). Projections of PAD prevalence demonstrated that the rise in the national prevalence of PAD will continue until around 2030 followed by a decline towards 2050 (Figure 2). Among individuals aged ≥80 years, the prevalence was projected to reach a maximum of 8.9% for men vs. 6.5% for women before beginning to decline.

Conclusion

Within an unselected nationwide population, the incidence and all-cause mortality of PAD has declined over the last two decades. Concurrently, the prevalence increased, and this increasing trend was projected continue over the coming decade before reaching a breaking point around 2030, underscoring the continued need for health service to manage PAD and its complications in years to come.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Karen Elise Jensen's Foundation

Seroprevalence of SARS-CoV-2 antibodies in social housing areas in Denmark

BACKGROUND

COVID-19 is thought to be more prevalent among ethnic minorities and individuals with low socioeconomic status. We aimed to investigate the prevalence of SARS-CoV-2 antibodies during the COVID-19 pandemic among citizens 15 years or older in Denmark living in social housing (SH) areas.

METHODS

We conducted a study between January 8th and January 31st, 2021 with recruitment in 13 selected SH areas. Participants were offered a point-of-care rapid SARS-CoV-2 IgM and IgG antibody test and a questionnaire concerning risk factors associated with COVID-19. As a proxy for the general Danish population we accessed data on seroprevalence from Danish blood donors (total Ig ELISA assay) in same time period.

RESULTS

Of the 13,279 included participants, 2296 (17.3%) were seropositive (mean age 46.6 (SD 16.4) years, 54.2% female), which was 3 times higher than in the general Danish population (mean age 41.7 (SD 14.1) years, 48.5% female) in the same period (5.8%, risk ratios (RR) 2.96, 95% CI 2.78-3.16, p > 0.001). Seropositivity was higher among males (RR 1.1, 95% CI 1.05-1.22%, p = 0.001) and increased with age, with an OR seropositivity of 1.03 for each 10-year increase in age (95% CI 1.00-1.06, p = 0.031). Close contact with COVID-19-infected individuals was associated with a higher risk of infection, especially among household members (OR 5.0, 95% CI 4.1-6.2 p < 0,001). Living at least four people in a household significantly increased the OR of seropositivity (OR 1.3, 95% CI 1.0-1.6, p = 0.02) as did living in a multi-generational household (OR 1.3 per generation, 95% CI 1.1-1.6, p = 0.003). Only 1.6% of participants reported not following any of the national COVID-19 recommendations.

CONCLUSIONS

Danish citizens living in SH areas of low socioeconomic status had a three times higher SARS-CoV-2 seroprevalence compared to the general Danish population. The seroprevalence was significantly higher in males and increased slightly with age. Living in multiple generations households or in households of more than four persons was a strong risk factor for being seropositive. Results of this study can be used for future consideration of the need for preventive measures in the populations living in SH areas.

Effect of influenza vaccination on risk of COVID-19 - A prospective cohort study of 46,000 health care workers

The purpose of this study was to assess if influenza vaccination has an impact on the risk of COVID-19. A cohort of 46,112 health care workers were tested for antibodies against SARS-CoV-2 and filled in a survey on COVID-19 symptoms, hospitalization, and influenza vaccination. The RR of hospitalization due to SARS-CoV-2 for influenza vaccinated compared with unvaccinated participants was 1.00 for the seasonal vaccination in 2019/2020 (CI 0.56-1.78, p=1.00). Likewise, no clinical effect of influenza vaccination on development of antibodies against SARS-CoV-2 was found. The present findings indicate that influenza vaccination does not affect the risk of SARS-CoV-2 infection or COVID-19.

Testing Denmark: a Danish Nationwide Surveillance Study of COVID-19

"Testing Denmark" is a national, large-scale, epidemiological surveillance study of SARS-CoV-2 in the Danish population. Between September and October 2020, approximately 1.3 million people (age >15 years) were randomly invited to fill in an electronic questionnaire covering COVID-19 exposures and symptoms. The prevalence of SARS-CoV-2 antibodies was determined by point-of care rapid test (POCT) distributed to participants' home addresses. In total, 318,552 participants (24.5% invitees) completed the study and 2,519 (0.79%) were seropositive. Of the participants with a prior positive PCR test (n = 1,828), 29.1% were seropositive in the POCT. Although seropositivity increased with age, participants 61 years and over reported fewer symptoms and were tested less frequently. Seropositivity was associated with physical contact with SARS-CoV-2 infected individuals (risk ratio [RR] 7.43, 95% CI: 6.57-8.41), particular in household members (RR 17.70, 95% CI: 15.60-20.10). A greater risk of seropositivity was seen in home care workers (RR 2.09, 95% CI: 1.58-2.78) compared to office workers. A high degree of adherence with national preventive recommendations was reported (e.g., >80% use of face masks), but no difference were found between seropositive and seronegative participants. The seroprevalence result was somewhat hampered by a lower-than-expected performance of the POCT. This is likely due to a low sensitivity of the POCT or problems reading the test results, and the main findings therefore relate to risk associations. More emphasis should be placed on age, occupation, and exposure in local communities. IMPORTANCE To date, including 318,522 participants, this is the largest population-based study with broad national participation where tests and questionnaires have been sent to participants' homes. We found that more emphasis from national and local authorities toward the risk of infection should be placed on age of tested individuals, type of occupation, as well as exposure in local communities and households. To meet the challenge that broad nationwide information can be difficult to gather. This study design sets the stage for a novel way of conducting studies. Additionally, this study design can be used as a supplementary model in future general test strategy for ongoing monitoring of COVID-19 immunity in the population, both from past infection and from vaccination against SARS-CoV-2, however, with attention to the complexity of performing and reading the POCT at home.

Changes in antithrombotic treatment in patients with abdominal aortic aneurysmal disease and incident atrial fibrillation: a population-based case-crossover analyses

Background

Abdominal aortic aneurysmal (AAA) disease is associated with a high risk of cardiovascular events, and prophylaxis with platelet-inhibitors are recommended at diagnosis. Incident atrial fibrillation (AF) changes that indication to oral anticoagulative (OAC) therapy. However, it is unknown to what extent the recommended change of indication is reflected in the actual antithrombotic treatment in clinical practice.

Purpose

To evaluate the antithrombotic therapy after an incident diagnosis of atrial fibrillation in patients with established AAA.

Methods

In this population-based case-crossover study, using nationwide Danish registries, we identified all patients registered with a diagnosis of AAA between 1997 and 2018, and a subsequent diagnosis of AF. The case-crossover analysis was performed to compare the within-subject antithrombotic therapy in 1-year time-periods before and after AF diagnosis in the study population. A blanking period of 30 days before AF-diagnosis was applied to avoid bias from potentially delayed hospital diagnosis of AF (Figure 1.1). We excluded patients with no eligible reference window due to recent cohort entry and patients with no AF-related indication for shift to OAC (CHA2DS2-VASc score of &lt;1 in men and &lt;2 in women). Odds ratios (OR) with 95% confidence intervals (CIs) comparing antithrombotic therapy before and after AF diagnosis was calculated using McNemars test for matched pair's data. Subgroup analyses of patients diagnosed with AAA between 2011 and 2018 were performed to evaluate changes after introduction of current antithrombotic treatment regimens and direct oral anticoagulants.

Results

A total of 3052 patients were included in the case-crossover analyses. Mean age was 77.8 years and 22.3% were females. Median time from AAA to AF diagnosis was 4.6 years (IQR; 2.6–7.8). Stroke risk in the study population was high with a median CHA2DS2-VASc score of 4 (IQR: 3–5). In the case-period after AF diagnosis, 1004 prescription claims of platelet-inhibitors were registered compared with 1461 claims in the control-period before AF diagnosis, corresponding to a matched OR of 0.31 (95% CI, 0.26–0.36) (Figure 1.2). Conversely, there were 1392 prescription claims for OAC in the case-period compared with 355 in the control-period, corresponding to an OR of 15.75 (95% CI, 12.38–20.31). When restricting the study-population to patients diagnosed with AAA during 2011–2018, the OR was 0.11 (95% CI, 0.07–0.16) for a prescription claim of platelet-inhibitors and 17.7 (95% CI, 11.22–29.17) for OAC before and after AF diagnosis (Figure 1.2).

Conclusion

In patients with established AAA and high risk of stroke, incident AF was associated with low likelihood of treatment with platelet-inhibitor and a high likelihood of OAC-treatment compared with before AF. This association was further strengthened in patients diagnosed after 2011.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): The Obel Family Foundation, DenmarkThe Augustinus Foundation, DenmarkThe sponsors played no role in the study design; data collection, analysis, or interpretation; abstract writing; or in the decision to submit the abstract. Figure 1

Seroprevalence of SARS-CoV-2 antibodies and reduced risk of reinfection through 6 months: a Danish observational cohort study of 44 000 healthcare workers

OBJECTIVES

Antibodies to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) are a key factor in protecting against coronavirus disease 2019 (COVID-19). We examined longitudinal changes in seroprevalence in healthcare workers (HCWs) in Copenhagen and the protective effect of antibodies against SARS-CoV-2.

METHODS

In this prospective study, screening for antibodies against SARS-CoV-2 (ELISA) was offered to HCWs three times over 6 months. HCW characteristics were obtained by questionnaires. The study was registered at ClinicalTrials.gov, NCT04346186.

RESULTS

From April to October 2020 we screened 44 698 HCWs, of whom 2811 were seropositive at least once. The seroprevalence increased from 4.0% (1501/37 452) to 7.4% (2022/27 457) during the period (p < 0.001) and was significantly higher than in non-HCWs. Frontline HCWs had a significantly increased risk of seropositivity compared to non-frontline HCWs, with risk ratios (RRs) at the three rounds of 1.49 (95%CI 1.34-1.65, p < 0.001), 1.52 (1.39-1.68, p < 0.001) and 1.50 (1.38-1.64, p < 0.001). The seroprevalence was 1.42- to 2.25-fold higher (p < 0.001) in HCWs from dedicated COVID-19 wards than in other frontline HCWs. Seropositive HCWs had an RR of 0.35 (0.15-0.85, p 0.012) of reinfection during the following 6 months, and 2115 out of 2248 (95%) of those who were seropositive during rounds one or two remained seropositive after 4-6 months. The 133 of 2248 participants (5.0%) who seroreverted were slightly older and reported fewer symptoms than other seropositive participants.

CONCLUSIONS

HCWs remained at increased risk of infection with SARS-CoV-2 during the 6-month period. Seropositivity against SARS-CoV-2 persisted for at least 6 months in the vast majority of HCWs and was associated with a significantly lower risk of reinfection.

P3348Prevention of stroke in intracerebral haemorrhage survivors with atrial fibrillation (PRESTIGE-AF): a retrospective cohort study

Background

Atrial fibrillation (AF) patients surviving an intracerebral haemorrhage (ICH) present a clinical challenge. The PRESTIGE-AF trial is an ongoing trial designed to investigate the optimal stroke prevention strategy in AF patients who have suffered an ICH.

Purpose

To describe baseline clinical characteristics of a study population similar to the expected PRESTIGE-AF trial.

Methods

The patient population was identified from the Danish Stroke Registry, linked with additional registries to obtain information on comorbidities and medication. Specific incl/excl criteria from the PRESTIGE-AF trial were applied, including indication for OAC treatment due to AF and the ICH was not related to trauma.

Results

From 2003–2015 a total of 1405 patients with AF and ICH were included, mean age of 79.4 years [Table]. 40% had suffered a “mild” index ICH, and approximately 25% had a “moderate” or a “severe” index event based on the SSS score. Hypertension (75%) and prior thromboembolic events (33%) were common comorbidities. In the year before the index ICH, 27% recieved antiplatelet therapy, 34% OAC, and 22% receiving both treatments.

Table 1 Demographics and clinical characteristics Percent (number) Number of patients 1,405 Females 695 (49.5) Age, mean (SD) 79.4 (8.8) Scandinavian Stroke Scale*, median (IQR) 40.0 (22.0–50.0) “Mild” intracerebral haemorrhage (43–58) 563 (40.1) “Moderate” intracerebral haemorrhage (26–42) 377 (26.8) “Severe” intracerebral haemorrhage (<26) 361 (25.7) Hypertension 1067 (75.9) Prior thromboembolism 460 (32.7) CHA2 DS2 -VASc score, mean (SD) 4.2 (1.3) Antiplatelet therapy (mono) 377 (26.8) VKA treatment 436 (31.0) NOAC treatment 40 (2.9) OAC and antiplatelet treatment 311 (22.1) *Scale from 0–58; lower score indicates more severe stroke; 7% missing information.

Conclusion

The identified study population using the criteria for the PRESTIGE-AF trial were generally elderly and had a high prevalence of hypertension and prior stroke. The PRESTIGE-AF trial is required to determine optimal stroke prevention treatment in a population of AF patients presenting with ICH.

Acknowledgement/Funding

This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No. 754517

P3760Temporal trends in stroke prevalence and its associations with changing patterns of antithrombotic regimens in patients with atrial fibrillation and a wide spectrum of coronary artery disease

Introduction

Much of the morbidity and mortality associated with atrial fibrillation (AF) is due to cerebrovascular thrombo-embolic complications such as ischemic stroke. Antithrombotic therapy is the fundamental treatment for many cardiovascular conditions, e.g. coronary artery disease (CAD), AF, and stroke to prevent thrombotic complications and death, but many patients have both CAD and AF. Dual antiplatelet therapy (DAPT) with acetylsalicylic acid (ASA) and a P2Y12 inhibitor has proven most effective in patients with recent myocardial infarction (MI) or after percutaneous coronary intervention (PCI), whereas for AF, oral anticoagulation (OAC) is most effective, with lesser efficacy but similar bleeding using DAPT. We investigated temporal trends in stroke prevalence and its associations with changing patterns of antithrombotic regimens in patients with non-valvular AF and a wide spectrum of co-incident CAD.

Methods

The Silesian TRiplE Antithrombotic Therapy (TREAT) Registry enrolled 14,873 patients with CAD from 2006 to 2014: 9,379 with stable CAD (SCAD), 1,460 with unstable angina (UA), 1,760 with NSTEMI and 2,328 with STEMI. We compared temporal trends in clinical features, an incidence of clinical events and patterns of antithrombotic regimens.

Results

2,194 of 14,873 patients (14.6%) had AF, including 74.1% with SCAD, 7.7% with UA, 10.1% with NSTEMI and 8.1% with STEMI. The AF prevalence increased from 11.2% in 2006 to 17.2% in 2014 which may be attributed to increasing age from 62.7 in 2006 to 67.8 in 2014. Overall, there was an increasing use of OAC therapy alone or with SAPT or DAPT from 46–50% in 2006–7 to 77–86%% in 2013–14. There was a steady increase in utilization of TREAT, and OAC ± SAPT throughout the study period (Panel A): after PCI there was a substantial increase in TREAT with a steady decline in DAPT (Panel B). The stroke rates declined throughout the study period from 3.3% in 2004 through a peak of 4.9% in 2011 to 1.1% in 2014. Conversely, bleeding rates increased from 6.0% to 10.5%.

Conclusions

There has been an increase followed by a progressive decline in stroke rate despite increasing age and AF prevalence in patients with both CAD and AF. This phenomenon is associated with a significant increase in the proportion of AF patients receiving guideline-recommended OAC therapy, driven by a steady increase in the utilization of triple antithrombotic therapy in patients following ACS or stent implantation and increase in OAC monotherapy in patients without ACS or stent implantation. This positive effect on stroke incidence is offset by increased bleeding risk, necessitating a closer look at the duration of triple therapy for ACS or PCI, and the long-term requirement for additional antiplatelet treatment in uncomplicated CAD.

408Albuminuria as a predictor of incident ischemic stroke and myocardial infarction in patients with type 2 diabetes but without cardiovascular disease: A Danish cohort study

Background

Risk stratification in patients with type 2 diabetes continues to be an important priority in the management of diabetes-related morbidity and mortality. International guidelines generally recognize patients with diabetes and cardiovascular disease as high-risk patients. Risk stratification is, however, more uncertain in diabetes patients without cardiovascular disease. Micro- and macroalbuminuria have previously been identified as predictors of cardiovascular events and mortality in general cohorts of diabetes patients. However, less is known about the predictive value of albuminuria in patients with diabetes but without established cardiovascular disease.

Purpose

We aimed to examine the association between albuminuria level and the risk of ischemic stroke, myocardial infarction, and all-cause mortality in patients with type 2 diabetes and without a diagnosis of cardiovascular disease.

Methods

We linked Danish nationwide registries to identify patients with type 2 diabetes and without cardiovascular disease from May 2005 through June 2015. Based on two consecutive measurements of the urinary albumin excretion rate or albumin-to-creatinine ratio patients were stratified in categories of normoalbuminuria, microalbuminuria, and macroalbuminuria. Patients were followed for the outcomes ischemic stroke, myocardial infarction, and all-cause mortality until December 31, 2015. Five-year risk of outcomes were presented as cumulative incidence functions (with death as a competing event). Associations between albuminuria level and incidence of ischemic stroke, myocardial infarction, and all-cause mortality were evaluated with Cox proportional hazard regression adjusted for cardiovascular risk factors.

Results

The study population included 78,841 patients with type 2 diabetes (44.7% females, mean age 63.2). When comparing patients with microalbuminuria to patients with normoalbuminuria in an age- and sex-adjusted analysis, we found hazard ratios (HRs) of 1.45 (95% CI: 1.24–1.69), 1.45 (95% CI: 1.24–1.70), and 1.50 (95% CI: 1.39–1.61) for ischemic stroke, myocardial infarction, and all-cause mortality, respectively. Furthermore, macroalbuminuria was associated with HRs of 2.05 (95% CI: 1.70–2.48), 2.25 (95% CI: 1.86–2.71), and 2.03 (95% CI: 1.85–2.23) for ischemic stroke, myocardial infarction, and all-cause mortality, respectively. Similar results were found after adjusting for cardiovascular risk factors.

Conclusions

In this nationwide cohort study of patients with type 2 diabetes but without cardiovascular disease, patients with micro- and macroalbuminuria had a higher risk of incident ischemic stroke, myocardial infarction, and all-cause mortality. This finding supports that patients with micro- or macroalbuminuria should be screened regularly and followed closely in clinical practice. Moreover, these findings suggest that patients with type 2 diabetes and micro- or macroalbuminuria may benefit from intensive vascular risk reduction.

P2246Maternal and foetal outcomes of anticoagulation in pregnant women with preconception venous thromboembolism

Background

Anticoagulation is essential to prevent recurrent venous thromboembolism (VTE) during pregnancy in women with a history of preconception VTE. However, information on the safety of anticoagulant drugs in this setting is limited.

Purpose

To investigate the risk of maternal and foetal adverse outcomes associated with anticoagulant exposure during pregnancy.

Methods

Nationwide cohort of all pregnant women in Denmark with preconception VTE, 2000–2017. We linked individual-level data from nationwide registries on anticoagulant exposure, maternal and foetal outcomes.

Results

Among 5,099 pregnancies in 3,246 women with preconception VTE (mean age 31 years, 41% nulliparous), 36.4% were exposed to anticoagulants during first trimester (66.4% low-molecular-weight heparin (LMWH), 31.9% VKA, and 1.8% NOAC (Table). No maternal deaths occurred. Maternal outcomes were comparable among LMWH and unexposed women, whereas recurrent VTE and foetal loss was more prevalent in VKA and NOAC exposed women. Foetal risk was lowest in unexposed and LMWH exposed, whereas preterm birth was prevalent in VKA and NOAC exposed.

Table 1. Maternal and foetal outcomes in pregnant women with preconception VTE according to first trimester anticoagulant exposure Maternal outcomes No anticoagulants LMWH VKA NOAC Total pregnancies/singleton foetuses, N 3,244/2,722 1231/1,124 591/442 33 /26 Recurrent VTE, % (N) 2.7 (89) 3.3 (41) 6.4 (38) – (<5) Antenatal bleeding, % (N) 2.3 (73) 2.7 (33) 1.5 (9) 0 Preeclampsia, % (N) 3.0 (98) 2.1 (26) 4.4 (26) – (<5) Foetal loss, % (N) 13.4 (436) 6.6 (81) 22.2 (131) 21.2 (7) Foetal outcomes in live singleton births, except stillbirth   Stillbirth, % (N) 0.6 (17) 0.6 (7) – (<5) 0   Mean gestational age, days/birthweight, gram 246/3,458 246/3,471 238/3,212 243/3,138   Preterm birth (<37 weeks), % (N) 41.1 (1,111) 38.3 (428) 63.2 (277) 57.7 (15)   Very preterm birth (<28 weeks), % (N) 0.9 (24) 1.3 (14) 2.7 (12) 0   Small for gestational age, % (N) 4.2 (109) 4.5 (49) 4.8 (20) – (<5)   Mean 5-minute Apgar score, (sd) 9.8 (0.8) 9.8 (0.7) 9.8 (1.0) 9.7 (1.0)   Congenital defects 8.4 (226) 9.0 (100) 10.0 (44) – (<5) Counts are supressed in cells with <5 observations to prevent disclosure of potentially identifiable information.

Conclusion

Our findings are reassuring and in support of the recommendation of LMWH for pregnant women with prior VTE. Few women were exposed to NOAC during pregnancy, and the safety of NOACs cannot be substantiated with the current level of evidence.

Acknowledgement/Funding

The Obel Family Foundation partly funded this research by an unrestricted grant.

210Predictors of thromboembolism in patients with atrial fibrillation and valvular heart disease according to the EHRA classification: beyond mitral stenosis and mechanical prosthetic heart valves

Background

Atrial fibrillation (AF) and valvular heart disease (VHD) often coexist. They are independent causes of mortality and morbidity, and both have been associated with risk of thromboembolic events. Historically, the definition of VHD in AF patients has been inconsistent, which led to the proposal of a new classification of AF patients with VHD: the “Evaluated Heartvalves, Rheumatic or Artificial” (EHRA) valve classification, categorizing patients into: EHRA Type 1 VHD and EHRA Type 2 VHD. EHRA Type 1 VHD comprises AF patients with mitral stenosis (moderate-severe, of rheumatic origin) or a mechanical prosthetic valve replacement. EHRA Type 2 VHD includes AF patients with any other heart valve disease or a bioprosthetic valve replacement. The thromboembolic risk in this latter heterogeneous group is uncertain and, thus, identifying clinically relevant predictors of thromboembolism will facilitate more individualized risk stratification and identify high-risk subgroups, thereby, optimize prevention strategies.

Purpose

In a large nationwide cohort study, we aimed to identify clinically relevant predictors of thromboembolism in AF patients with EHRA Type 2 VHD.

Methods

We conducted a cohort study of AF patients with co-existing EHRA Type 2 VHD, identified by ICD-10 codes using record linkage between nationwide registries in Denmark from 2000 through 2018. Time-to-event analysis was applied to describe the association between EHRA Type 2 VHD and risk of thromboembolism. We used a multivariable Cox proportional hazards regression model with time since incident AF diagnosis as the underlying time axis to estimate predictors of the outcome at 5-years of follow-up. Parameters included were clinically relevant risk factors, statin therapy, antithrombotic therapy, and time since VHD diagnosis.

Results

A total of 27,254 patients with EHRA Type 2 VHD was identified. After 5 years of follow-up, the rate of thromboembolism was 3.27 per 100 person-years. History of thromboembolism (HR: 4.85, 95% CI: 4.43–5.31) and age ≥75 (HR: 1.97, 95% CI: 1.70–2.28) were the strongest predictors of thromboembolism, but age 65–74, female sex, vascular disease, diabetes mellitus, hyperlipidemia/hypercholesterolemia, history of bleeding, and increasing CHA2DS2-VASc score were also independent predictors [Figure].

Predictors of thromboembolism

Conclusion

Among AF patients with VHD beyond mitral stenosis and mechanical prosthetic heart valves, the rate of thromboembolism is high after 5 years of follow-up. The strongest clinically relevant predictors of thromboembolism are history of thromboembolism and age ≥75. Future studies examining the optimal antithrombotic prevention strategy for EHRA Type 2 VHD are encouraged.

Acknowledgement/Funding

The study was supported by “The BMS/Pfizer European Thrombosis Investigator Initiated Research Program 2018 (ERISTA)” and the Obel Family Foundation.

[Review of Early Warning Score in preventing sudden critical illness and death]

Early Warning Score (EWS) are used extensively to identify patients at risk of deterioration during hospital admission. The validation of EWS has primarily focused on investigating predictive validity, i.e. the association between EWS and severe adverse events. Few studies have tested, whether EWS work in the clinical setting, and if it prevents severe adverse events from occurring. Many of these studies have methodological limitations, and their clinical relevance could be questioned. Currently, there is limited evidence to support, that the implementation of EWS reduces the occurrence of severe adverse events.

Maternal death due to extended spectrum beta-lactamase-producing E. coli: a warning for the future?

We describe a maternal death due to necrotising fasciitis caused by an extended spectrum beta-lactamase-producing Escherichia coli resistant to routinely used antimicrobial agents. Necrotising fasciitis is a rare complication of septicaemia with a high mortality. Signs of infection were insidious and masked by the use of routine analgesic agents and concurrent preeclampsia. The incidence of infection with extended spectrum beta-lactamase-producing organisms is increasing both in the United Kingdom and globally and will need to be considered in the obstetric setting. The use of the current Modified Early Warning Scores was of limited help in this case. Where there is no response to routine antibiotics within 12h, microbiological review is indicated.

Mm, a new factor in the porcine M blood group system

By means of a new antiserum, Mm, the Mae phenotype can be shown to be controlled by the Maem allele, the Mef phenotype by either the original Mef or a new Mefm allele, and the Mbe(f) phenotype by the Mbe(f)m allele. The complexity of the porcine M system is now extended to 13 internationally recognized blood group factors controlled by at least 19 alleles.

A new Kd subgroup designated Kg in the porcine K blood group system

The K system in pigs included at least 6 internationally recognized blood group factors (Ka, Kb, Kc, Kd, Ke and Kf) controlled by the following alleles: Kacef, Kacf, Kade, Kae, Kbf and K- (Andresen, 1963; Brucks 1967, Hojný et al. 1967, Saison 1967, Hojný, Hradecký & Pazdera, 1979). This paper describes the results obtained with a new antiserum, Kg, by which subgrouping of the Kade allele into Kade or Kadeg is possible.

Congenital syphilis following negative antenatal screening

We report a case of severe early congenital syphilis in the infant of a mother who acquired syphilis in mid pregnancy. The mother had received full antenatal care including serological screening for syphilis. Congenital syphilis is re-emerging in a number of industrialised countries and this report demonstrates that some of the most serious cases cannot be prevented by routine antenatal screening.

Comparison of the lymphatic transport of a lipophilic drug from vehicles containing alpha-tocopherol and/or triglycerides in rats

The applicability of alpha-tocopherol as a lymphotropic carrier for a highly lipophilic drug has been evaluated. Transport to the intestinal lymph of the highly lipophilic model drug, Lu28-179, in rats after administration to the stomach in an alpha-tocopherol emulsion was compared with lymphatic transport after administration of a sesame oil emulsion and an alpha-tocopherol/sesame oil emulsion. Lymphatic transport of the triglycerides and of alpha-tocopherol was determined. A conscious rat model was used, and the mesenteric lymph was collected. There was no significant difference between the cumulative masses of triglyceride from the two emulsions containing triglyceride 24 h after administration. Administration of an alpha-tocopherol emulsion seemed to induce mobilization of endogenous triglyceride. The lymphatic transport of alpha-tocopherol was less than 1 mg 24 h after administration of both emulsions containing alpha-tocopherol. The absorption of Lu28-179 from the alpha-tocopherol emulsion was very low, with a lymphatic recovery of 0.05%. When administered in an alpha-tocopherol/sesame oil emulsion, the recovery of Lu28-179 increased sevenfold to 0.35%. However, after administration of Lu28-179 in a sesame oil emulsion, the lymphatic recovery increased a further 13-fold to 4.5%. In conclusion, the study showed that alpha-tocopherol did not promote lymphatic absorption of Lu28-179 and thus was not a good lymphotropic carrier, as compared with sesame oil. Alpha-tocopherol in combination with sesame oil was not a good lymphotropic carrier either. The non-absorbed alpha-tocopherol fraction in the intestine might be able to prevent the absorption of Lu28-179.

The effect of alpha-tocopherol on the in vitro solubilisation of lipophilic drugs

alpha-Tocopherol is an excellent solvent for many poorly soluble drugs. The aim of this work was to study whether or not the presence of alpha-tocopherol has an influence on the solubilisation of poorly soluble drugs in simulated intestinal fluids (SIF). The solubilizing capacity of mixed micelles containing alpha-tocopherol towards three lipophilic drugs was investigated. The solubilisation of alpha-tocopherol in an aqueous micellar phase was increased by the addition of monoglycerides (MG) and free fatty acids (FFA), preferably of medium chain length, as compared to a simple bile salt solution. The addition of alpha-tocopherol to mixed micellar solutions seems to have an effect on the solubilizing capacity, which can be correlated to the partition coefficient of the drug to be solubilised. A positive effect on the solubilisation of griseofulvin and felodipine was found. For a highly lipophilic drug (Lu28-179), a positive effect on solubilisation was observed only in media containing MG and FFA of medium chain length. Generally, alpha-tocopherol cannot be considered an important factor for the solubilisation of highly lipophilic drugs in SIF. The presence of lipolytic digestion products (LDP) of the proper chain length in relation to the drug to be solubilised is much more important.

Genetic variation at the growth hormone locus in a wild pig intercross; test of association to phenotypic traits and linkage to the blood group D locus

A polymorphism in the TATA-box of the porcine growth hormone (GH) gene was analysed in a wild pig/Large White intercross, in which 129 markers had been scored previously. Linkage analyses demonstrated that the GH locus belonged to a linkage group on chromosome 12 together with a previously unassigned marker, the erythrocyte antigen D (EAD) locus. The linear order of this linkage group is EAD-GH-S0096-S0090-S0106-arachidonate 12-lipoxygenase (ALOX12)-inhibin beta A (INHBA). The length of the linkage group was estimated at 93 cM (sex average). The effects of the GH genotype on growth and fat deposition traits were investigated using phenotypic data from the 191 F2 animals. No significant effect of GH was detected, and we therefore conclude that this locus does not play a major role in defining the genetic differences between the wild and Large White pigs for these traits.

A survey of birds in Denmark for the presence of Pneumocystis carinii

One hundred eighty-three toluidine blue O-stained necropsy lung imprint smears from different avian species were examined microscopically for Pneumocystis carinii. No cyst forms of the organism could be identified. Seventy-eight serum samples from a total of 155 chickens were examined by a competition enzyme-linked immunosorbent assay (ELISA) for antibodies to P. carinii; 53 serum samples were from individual chickens, and 25 samples were pools of sera from two to five chickens. Diluted 1:50, the 78 serum samples showed a specific ELISA-inhibition of 4% to 56% (the 95% confidence limit being 25% to 30% inhibition). Diluted 1:50, nine serum pools representing 34 chickens and 17 of the 53 individual serum samples (32.1%) showed an inhibition greater than 30%. No specific pneumocyst DNA could be detected in serum from 13 of the 53 chickens using polymerase chain reaction and dihydrofolate reductase gene as a specific probe. Specific antibodies to a 116,000-molecular-weight antigen of rat pneumocysts were shown in two (13.3%) of 15 individual chicken serum samples. The results indicate that P. carinii organisms do not commonly reside in the lungs of birds, although some birds may be exposed to external sources of organisms.

Antibiotic treatment of sinusitis in general practice. A double-blind study comparing ofloxacin and erythromycin

The present study compared ofloxacin and erythromycin in a double-blind study with parallel groups for clinical efficacy and the number and severity of adverse reactions in patients treated in general practice for acute or chronic sinusitis. All patients lived in medium-sized to large towns and rural districts in the northern and western parts of Sealand, Funen and eastern Jutland, Denmark. Three hundred and nineteen patients were enrolled in the study, of whom 280 were clinically evaluable. From this total number, 136 patients were treated with ofloxacin (31 males and 105 females) and 144 patients were treated with erythromycin (40 males and 104 females). Following administration of either ofloxacin 400 mg once daily or erythromycin 500 mg twice daily for 7-14 days, 94.9% of the ofloxacin-treated group and 94.4% of the erythromycin-treated group were cured of their infections. There was no difference in clinical efficacy. Complications occurred in 18 of 155 patients in the ofloxacin-treated group and 32 of 164 in the erythromycin-treated group (P < 0.05), corresponding to 27 and 45 symptoms respectively (P < 0.01). This difference in adverse reactions principally involved gastrointestinal symptoms, i.e. 19 in the ofloxacin-treated group and 41 in the erythromycin-treated group (P < 0.01). Present findings show that the two antibiotics are comparable as to clinical efficacy, but the frequency of adverse reactions is significantly higher in the erythromycin-treated group due to the greater incidence of gastrointestinal adverse reactions.

On-the-job training

The quality of training given by the security department has a direct impact on the job performances of each security officer. The author discusses how on-the-job training can be a vital part of the training effort when done properly and effectively.

Characterization of 24 porcine (dA-dC)n-(dT-dG)n microsatellites: genotyping of unrelated animals from four breeds and linkage studies

Twenty-four PCR primer pairs were designed for the detection of porcine microsatellites. Polymorphism was investigated in 76 unrelated animals from four different breeds: Duroc, Landrace, Hampshire, and Yorkshire. Compared with human microsatellites, a general lower heterozygosity was detected; however, for each microsatellite a significant variation between breeds in number of alleles and heterozygosity was seen. Mean heterozygosity was found to be significantly higher (P < 0.01%) in the Yorkshire breed than in the other three breeds. Linkage analyses with the CEPH linkage packet were performed in a backcross family comprising 45 animals, of which 43 had informative meioses. Ten of the microsatellites could be assigned to six different linkage groups, demonstrating that linkage mapping with microsatellites can be carried out with great efficiency in a relatively small number of animals. Four of the linkage groups represent Chromosomes (Chrs) 4, 6, 7, and 8 respectively, while two linkage groups are unassigned.

Incidence of spontaneous bacterial peritonitis in patients with ascites. Diagnostic value of white blood cell count and pH measurement in ascitic fluid

During a 21-month period, 65 consecutive patients admitted with ascites were included in a prospective study of the incidence of spontaneous bacterial peritonitis, and paracentesis was performed on admission. The ascitic fluid was cultured, ascitic leucocytes were counted and pH was measured. Bacterial growth was found in five patients with chronic liver disease, who were diagnosed as having spontaneous bacterial peritonitis (SBP), since no intra-abdominal focus could be demonstrated. Thus, the incidence of SBP in this material was 7.7% (95% confidence limits: 2.5-17%). SBP was caused by Escherichia coli (n = 3), coagulase negative staphylococcus (n = 1), and Bacteroides species (n = 1). Abdominal tenderness, abnormal intestinal sounds, fever and hepatic encephalopathy were equally frequent in the group with SBP and in patients with sterile ascites. Infection was not anticipated in any of the patients with SBP. In contrast to several previous studies, neither ascites pH nor ascites leucocyte counts were any help in obtaining a rapid diagnosis. Survival time of patients with SBP was significantly shorter than of patients without SBP.

Non-typhoid Salmonella bacteraemia in Greater Copenhagen 1984 to 1988

A retrospective survey of non-typhoid Salmonella bacteraemia in the period 1984 to 1988 was carried out by the five departments of clinical microbiology in Greater Copenhagen. A total of 168 patients were identified. A gradual increase was observed from 11 cases in 1984 to 58 cases in 1988. The corresponding incidence per 100,000 inhabitants in Copenhagen rose from 0.9 in 1984 to 5.0 in 1988. During the same period the total registered incidence of human Salmonella infections in Denmark increased from 17.6 to 67.4 per 100,000 inhabitants. The serotype most often isolated from bacteraemic patients was Salmonella dublin followed by Salmonella enteritidis and Salmonella typhimurium. Salmonella dublin demonstrated enhanced invasive and pathogenic properties. Predisposing factors were present in 56% of the patients; the most common was malignant disease. A fatal or complicated course of the bacteraemia was observed more frequently in patients with underlying diseases than in persons who had previously been healthy. A total of 17% of the patients died; one-fifth of these had a ruptured aortic aneurysm. It is concluded that the substantial increase in the number of cases and the often serious course taken by the infection demonstrate a need for increased efforts at prophylaxis.

[Diphtheria in Denmark 1956-1989. Occurrence of Corynebacterium diphtheriae and other diphtheria toxigenic bacteria]

The public immunization program against diphtheria, established in 1941, has almost eradicated the disease in Denmark, and 1956 became the first year without any notified cases. Since then, toxigenic strains have only been isolated five times--three cases of clinical diphtheria due to Corynebacterium diphtheriae biovar. mitis and two cases of tonsillitis/pharyngitis due to Corynebacterium ulcerans. The source of the infection was not identified in any of the cases. The first case of diphtheria in 1968 was imported from abroad. The following two cases in 1983 and 1985 were due to strains of the same phage type and peptide profile as the strains isolated during the epidemic in Sweden in 1984-1986. This indicates that the Danish cases and the Swedish epidemic derived from the same source. The diphtheria immunity of the Danish population is decreasing, and the level of protection is approaching the Swedish level. The impact is that a situation like that in Sweden may be anticipated with diphtheria epidemic in the lowest socio-economical groups--the skid row dwellers, alcoholics and drug abusers--if the immunization program against diphtheria is not intensified.

Measurement of renin and prorenin in cattle, hog and horse

1. Species specific problems complicating the measurement of prorenin and renin concentrations were studied in bovine, hog and horse plasma. 2. In contrast to horse renin, bovine and hog renin reacted with rat angiotensinogen, allowing measurement of the plasma renin concentration in cattle and hog with rat angiotensinogen as exogenous substrate. 3. Trypsin treatment of plasma in order to activate prorenin generated an interfering angiotensin I immunoreactive material in all three species, most extensively in horse plasma. 4. This material could be removed in bovine and hog plasma by a cation-exchange resin, allowing an assay of the plasma prorenin concentration to be constructed in these species. 5. Another strategy has to be followed in order to measure prorenin and renin concentrations in horse plasma.

[Bacteremia caused by zoonotic Salmonella types in greater Copenhagen in 1984-1988]

The five departments of clinical microbiology in Greater Copenhagen have together carried out a retrospective review of bacteraemia caused by the zoonotic Salmonella serotypes in the period 1984-1988 in the municipalities of Copenhagen and Frederiksberg and in the County of Copenhagen. A gradual increase in frequency was observed from 11 cases in 1984 to 58 cases in 1988. The serotype most commonly isolated was Salmonella dublin followed by Salmonella enteritidis and Salmonella typhimurium. S. dublin was found to be more invasive and more virulent than the other serotypes. Predisposing factors were present in 56% of the patients; the commonest of these was malignant disease. Fatal or complicated course of the disease were observed more frequently in predisposed patients than in persons who had previously been healthy. A total of 17% of the patients died and one fourth of these had ruptured aortic aneurysm probably on account of Salmonella arteritis. 20% developed recurrence of bacteraemia while in the remaining patients the disease ran an uncomplicated course. It is concluded that the marked increase in the number of cases and the serious course taken by the infection demonstrate a definite need for increased prophylactic efforts in the food industry.

Type I reactions directed against Pneumocystis carinii in AIDS patients

Type I allergy directed against Pneumocystis carinii (PC) has been investigated in 14 patients with AIDS. The Pneumocystis carinii pneumonia often shows a rapid and severe course, and type I allergy against the parasite might be a pathogenic co-factor in the interstitial lung inflammation. In twelve of the AIDS patients the clinical symptoms and course of illness indicated a PC pneumonia. The basophil histamine release test was used as a sensitive test to detect type I allergy against PC. Eight of the patients showed significant histamine release when stimulated with PC. In contrast, only two patients in the group of 12 HIV antibody-positive homosexual men and none in the control group of 13 heterosexual men released histamine. The histamine release was mediated by an immunological reaction, since the release was abolished and regained by removal from and refixation to the cell surface of the cell-bound immunoglobulins before the antigen challenge. The results suggest an involvement of type I allergy as a pathogenic co-factor in Pneumocystis carinii pneumonia.

Enzyme-linked immunosorbent assay compared with indirect immunofluorescence test for detection of Pneumocystis carinii specific immunoglobulins G, M, and A

An ELISA to measure Pneumocystis carinii-specific IgG, IgM, and IgA has been developed. The antigen was prepared from purified cysts by sonication and ultracentrifugation. Antigen particles with sedimentation coefficients less than 165 S were used. The technique has been compared with indirect immunofluorescence, using whole cysts as antigen. Ninety human sera were assayed. The results were significantly correlated. The ELISA-technique was more sensitive, and owing to the soluble antigen the daily variation was less than 1 per cent. The technique is useful for quick and reliable detection of Pneumocystis carinii antibodies in a routine laboratory.

Humoral and cellular responses to Pneumocystis carinii, CMV, and herpes simplex in patients with AIDS and in controls

The titers of IgG and IgA to Pneumocystis carinii in 36 AIDS patients did not differ significantly from those in 31 controls. Only 2/15 patients (13%) with P. carinii pneumonia (PCP) had titers of IgM antibodies greater than or equal to 5, which is significantly less frequent than in 32 controls (62%) and in 21 AIDS patients without PCP (43%). The risk of PCP was 5 times higher in patients without IgM antibodies to P. carinii than in patients who had these antibodies. A significantly higher percentage of those without PCP (57%) showed increasing titers of IgM antibodies to P. carinii in the second of paired samples taken about 6 months apart, compared with whose with PCP (9%; p = 0.05). All patients had high titers of antibodies to CMV and HSV and normal total concentrations of immunoglobulins. None of the patients responded in lymphocyte transformation to P. carinii, CMV, or HSV antigens. There is no obvious explanation to the selective lack of IgM antibodies to P. carinii in patients with PCP. Lack of IgM antibodies may be a marker for an immunodeficiency to P. carinii.

Septicemia with Agrobacterium species from a permanent vena cephalica catheter. A case report

A case of Agrobacterium septicemia is reported in a 47-year-old woman with disseminated adenomcarcinoma mammae and a permanent vena cephalica catheter.

Lymphocyte transformation response to pokeweed mitogen as a predictive marker for development of AIDS and AIDS related symptoms in homosexual men with HIV antibodies

To identify factors that may predict the development of the acquired immune deficiency syndrome (AIDS) or AIDS related symptoms various immunological measurements were studied in a group of homosexual men attending screening clinics for AIDS in Copenhagen. Fifty seven men whose ratio of T helper lymphocytes to T suppressor lymphocytes (CD4:CD8 ratio) was less than 1.0 before the study began were included. Forty two were positive for antibody to the human immunodeficiency virus (HIV), of whom 38 were reinvestigated after a median observation period of 10 months. Among the seropositive men the transformation responses to pokeweed mitogen and cytomegalovirus and the absolute count of CD4 positive lymphocytes were the most common abnormal values. In particular, a low relative response to pokeweed mitogen on initial investigation correlated with a worsened clinical condition on reinvestigation. The risk of a worsened clinical condition was 55 times higher in seropositive men whose responses to pokeweed mitogen were low than in other seropositive men. The corresponding relative risks for low transformation responses to cytomegalovirus and for a decreased absolute count of CD4 positive lymphocytes were 18 and six. The relative response to pokeweed mitogen is therefore a very sensitive short term predictive marker of the clinical condition of seropositive patients who have a CD4:CD8 ratio of less than 1.0.

Bacteremia in connection with transurethral resection of the prostate

A bacteriological survey of 50 consecutive patients undergoing transurethral resection of the prostate was performed. Preoperatively, 28% of the patients had asymptomatic bacteriuria. In the postoperative period, 46% of all the patients developed transient bacteremia. A significantly higher rate of bacteremia was found in patients with hypertrophy of the prostate than in those with cancer of the prostate and in patients undergoing long-lasting surgical intervention. Patients who developed bacteremia due to pathogenic bacteria were hospitalized for a significantly longer period of time.

Double-antibody sandwich enzyme-linked immunosorbent assay for rapid detection of toxin-producing Corynebacterium diphtheriae

An enzyme-linked immunosorbent assay for determining the toxigenicity of Corynebacterium diphtheriae is presented. The assay uses hyperimmune horse diphtheria antitoxin as a capture antibody and mouse monoclonal diphtheria antitoxin as a detecting antibody. Growth of bacteria and capture of diphtheria toxin by antitoxin are carried out in one step. Toxin produced by as little as 100 toxin-producing corynebacteria is detectable, corresponding to a sensitivity of 10 ng of diphtheria toxin per ml. Demonstration of toxin after incubation of the bacteria for 4.75 h, as well as after 18 h, was in accordance with the modified Elek gel diffusion method and the guinea pig inoculation test. However, heavy inocula incubated overnight produced significantly lower optical density than did diluted inocula; thus, the higher optical density was used as an indicator of toxin production. A decrease in optical density was also seen by shortening the incubation time. For laboratory safety, ethanol was added to the microtiter plate wells before washing out of the bacteria. This resulted in a further decrease in optical density. Using 4.75-h incubation time gave a single false-negative result. No false-positive results were ever seen. Incubation for 18 h is suitable for large-scale screening, and 4.75 h of incubation is suitable for rapid identification of toxin-producing C. diphtheriae.

Improved diagnosis of strongyloides stercoralis by seven consecutive stool specimens

Seven consecutive stool cultures have been used in order to diagnose strongyloidiasis. The study took place in the follow up period after treatment and seventy patients participated. The diagnostic sensitivity of the seven consecutive cultures compared to a single examination was increased from two to five times.