Use of physical examination, electrocardiography, radiography, and biomarkers to predict echocardiographic stage B2 myxomatous mitral valve disease in preclinical Cavalier King Charles Spaniels

INTRODUCTION

Cavalier King Charles Spaniels (CKCS) are predisposed to developing myxomatous mitral valve disease (MMVD). Dogs with stage B2 MMVD benefit from medication.

OBJECTIVES

To develop (1) breed-specific cut-offs for individual screening tests and (2) predictive models utilizing physical examination (PE), ECG, radiograph, and blood-based biomarker variables in combination for identification of echocardiographic stage B2 MMVD in preclinical CKCS.

ANIMALS

Adult, preclinical CKCS not receiving cardiac medications (N = 226).

MATERIALS AND METHODS

Prospective, cross-sectional study. Enrolled CKCS underwent PE, ECG, radiography, Doppler blood pressure measurement, echocardiography, and biomarker testing. Dogs were grouped by MMVD stage using echocardiography only. The discriminatory ability of individual tests to identify stage B2 was assessed, and prediction models were developed using variables derived from four 'tests' (PE, ECG, radiography, and biomarkers).

RESULTS

N-terminal pro-B-type natriuretic peptide (NT-proBNP) and radiographic vertebral heart size (VHS) had the best discriminatory ability of individual diagnostic tests to differentiate stage A/B1 CKCS from stage B2, with an area under the curve (AUC) of 0.855 and 0.843, respectively. An NT-proBNP ≥1138 pmol/L or a VHS ≥11.5 had high specificity for predicting stage B2 (90.1% and 90.6%, respectively). Prediction models incorporating variables from multiple tests had better discriminatory ability than single tests. The four-test prediction model had an AUC of 0.971. Three and two-test models had AUCs ranging between 0.925-0.959 and 0.895-0.949, respectively.

CONCLUSIONS

Both NT-proBNP and VHS have good utility for predicting echocardiographic stage B2 MMVD in CKCS as individual tests. Prediction models incorporating multiple test variables have superior discriminatory ability.

Veterinary echocardiographers' preferences for left atrial size assessment in dogs: the BENEFIT project

INTRODUCTION/OBJECTIVES

Veterinary echocardiographers' preferences for left atrial (LA) size assessment in dogs have never been systematically investigated. The primary aim of this international survey study was to investigate echocardiographers' preferences for LA size assessment in dogs. The secondary aim was to investigate echocardiographers' preferences for assessing LA size in subgroups based on geographic, demographic, and professional profiles.

ANIMALS, MATERIALS, AND METHODS

An online survey instrument was designed, verified, and distributed globally to the veterinary echocardiographers.

RESULTS

A total of 670 echocardiographers from 54 countries on six continents completed the survey. Most echocardiographers (n = 621) used linear two-dimensional (2D)-based methods to assess LA size, 379 used subjective assessment, and 151 used M-mode-based methods. Most commonly, echocardiographers combined linear 2D-based methods with subjective assessment (n = 222), whereas 191 used linear 2D-based methods alone. Most echocardiographers (n = 436) using linear 2D-based methods preferred the right parasternal short-axis view and indexed the LA to the aorta. Approximately 30% (n = 191) of the echocardiographers who performed linear measurements from 2D echocardiograms shared the same preferences regarding dog position, acquisition view, indexing method, and identification of the time-point used for the measurement. The responses were comparably homogeneous across geographic location, training level, years of performing echocardiography, and type of practice.

DISCUSSION/CONCLUSION

Most veterinary echocardiographers assessed LA size in dogs using linear 2D echocardiography from a right parasternal short-axis view, and by indexing the LA to the aorta. The respondents' preferences were similar across geographic, demographic, and professional backgrounds.

Veterinary echocardiographers' preferences for left atrial size assessment in cats: the BENEFIT project

INTRODUCTION/OBJECTIVES

Veterinary echocardiographers' preferences for left atrial (LA) size assessment in cats have not been systematically investigated. The primary aim of this prospective exploratory study was to investigate echocardiographers' preferences concerning LA size assessment in cats. A secondary aim was to investigate echocardiographers' preferences for assessing LA size in subgroups based on geographic, demographic, and professional profiles.

ANIMALS, MATERIALS, AND METHODS

An online survey instrument was designed, verified, and distributed globally to veterinary echocardiographers.

RESULTS

A total of 655 veterinary echocardiographers from six continents and 54 countries, working in specialty practice (56%) and in general practice (38%), provided data. Linear two-dimensional (2D) technique was favored by most echocardiographers (n = 612) for LA size assessment. Most commonly, respondents combined linear 2D with subjective assessment (n = 227), while 209 used linear 2D-based methods alone. Most echocardiographers using linear 2D-based methods preferred the right parasternal short-axis view and to index the LA to the aorta (Ao). Approximately 10% of the respondents obtained LA dimensions from a right parasternal long-axis four-chamber view. Approximately one-third of echocardiographers that made linear measurements from 2D echocardiograms shared the same preferences regarding cat position, acquisition view, indexing method and time point identification for the LA measurement. The responses were comparably homogeneous across geographic location, level of training, years performing echocardiography, and type of practice.

DISCUSSION/CONCLUSION

Most veterinary echocardiographers assessed LA size in cats using linear 2D echocardiography from a right parasternal short-axis view, and indexed LA to Ao. Respondents' preferences were similar over geographic, demographic, and professional backgrounds.

Advanced imaging in an adult dog with anomalous origin of the left coronary artery from the pulmonary artery and extensive collateral coronary circulation

A three-year-old, spayed female, Bichon Frise was diagnosed with an anomalous origin of the left coronary artery from the pulmonary artery, a rare congenital coronary artery defect which has only been reported in two other dogs. Echocardiography was initially performed, though the final diagnosis was made with angiography and computed tomography angiography. An extensive network of collateral coronary circulation allowed for communication between the dilated, tortuous right coronary artery, and the anomalous left coronary artery. Though collateral circulation likely prolonged the patient's life, it is suspected that coronary steal phenomenon and chronic myocardial ischemia ultimately led to fatal ventricular arrhythmias. The dog died suddenly at the age of six, three years after initial diagnosis.

Prediction of clinically important acquired cardiac disease without an echocardiogram in large breed dogs using a combination of clinical, radiographic and electrocardiographic variables

INTRODUCTION

Large breed (LB) dogs develop dilated cardiomyopathy (DCM) and myxomatous mitral valve disease (MMVD). Echocardiography is required for a definitive diagnosis but is not always available. Our objective was to assess the clinical utility of thoracic radiographs alone and in combination with physical examination and electrocardiography findings for the prediction of clinically important DCM or MMVD in LB dogs.

ANIMALS

Four hundred fifty-five client-owned dogs ≥20 kg with concurrent thoracic radiographs and echocardiogram.

MATERIALS AND METHODS

Medical records were reviewed and stored thoracic radiographs and echocardiographic images were measured to classify dogs as normal heart size (NHS), preclinical DCM, clinical DCM, preclinical MMVD (with cardiomegaly), clinical MMVD, or equivocal. Dogs with preclinical MMVD, without cardiomegaly, were classified as NHS. Vertebral heart size (VHS) and vertebral left atrial size (VLAS) were measured. Receiver operating characteristic curves and prediction models were derived.

RESULTS

Prevalence of MMVD (39.3%) was higher than the prevalence of DCM (24.8%), though most MMVD dogs (67.0%) lacked cardiomegaly and were classified as NHS for analysis. The area under the curve for VHS to discriminate between NHS and clinical DCM/MMVD or preclinical DCM/MMVD was 0.861 and 0.712, respectively, while for VLAS, it was 0.891 and 0.722, respectively. Predictive models incorporating physical examination and electrocardiography findings in addition to VHS/VLAS increased area under the curve to 0.978 (NHS vs. clinical DCM/MMVD) and 0.829 (NHS vs. preclinical DCM/MMVD).

CONCLUSIONS

Thoracic radiographs were useful for predicting clinically important DCM or MMVD in LB dogs, with improved discriminatory ability when physical examination abnormalities and arrhythmias were accounted for.

Functional gene categories differentiate maize leaf drought-related microbial epiphytic communities

The phyllosphere epiphytic microbiome is composed of microorganisms that colonize the external aerial portions of plants. Relationships of plant responses to specific microorganisms–both pathogenic and beneficial–have been examined, but the phyllosphere microbiome functional and metabolic profile responses are not well described. Changing crop growth conditions, such as increased drought, can have profound impacts on crop productivity. Also, epiphytic microbial communities provide a new target for crop yield optimization. We compared Zea mays leaf microbiomes collected under drought and well-watered conditions by examining functional gene annotation patterns across three physically disparate locations each with and without drought treatment, through the application of short read metagenomic sequencing. Drought samples exhibited different functional sequence compositions at each of the three field sites. Maize phyllosphere functional profiles revealed a wide variety of metabolic and regulatory processes that differed in drought and normal water conditions and provide key baseline information for future selective breeding.

Palliative combined cutting and high-pressure balloon valvuloplasty in six dogs with severe, symptomatic subaortic stenosis

INTRODUCTION/OBJECTIVES

Severe subaortic stenosis (SAS) is a congenital heart defect in dogs that often results in clinical signs and reduced survival. The objective of this study was to describe characteristics of dogs with severe, symptomatic SAS who underwent combined cutting and high-pressure balloon valvuloplasty (CB/HPBV).

ANIMALS, MATERIALS, AND METHODS

Retrospective description of the clinical characteristics, CB/HPBV procedural deviations from reported methodology and outcomes in a series of six client-owned dogs with severe, symptomatic SAS.

RESULTS

Breeds included two each of Newfoundland, Golden retriever, and German shepherd. Median age was 10.1 months (range: 5-72.3 months), and median weight was 25.5 kg (range: 21.8-36.4 kg). Before CB/HPBV, clinical signs were present in all dogs; four were managed for congestive heart failure (CHF). Three dogs had concurrent congenital heart disease. Median Doppler-estimated left ventricular outflow tract pressure gradient was pre-operatively 149.7 mmHg (range: 89.9-254.7 mmHg) and post-operatively 134.1 mmHg (range: 83.9-181.2 mmHg). Median aortoseptal angle was steep at 136° (range: 109-143°). Clinical improvement was documented in all dogs, based on temporary discontinuation of diuretics and/or owner-perceived reduction in clinical signs. At the time of writing, three dogs had died suddenly, one was euthanized because of recurrence of clinical signs, and one died in CHF. Median survival time was 26.4 months after procedure (range: 6.3-45.8 months). One dog remained alive at 44 months after procedure.

CONCLUSIONS

Palliative CB/HPBV is a potential therapeutic option for dogs with severe, symptomatic SAS complicated by concurrent congenital heart disease, arrhythmias, or CHF.

Quantitative assessment of two- and three-dimensional transthoracic and two-dimensional transesophageal echocardiography, computed tomography, and magnetic resonance imaging in normal canine hearts

INTRODUCTION

The objective of the study was to evaluate the accuracy of two- and three-dimensional (2D, 3D) transthoracic echocardiography (TTE), 2D transesophageal echocardiography, and computed tomography angiography (CTA) compared with cardiac magnetic resonance imaging (CMR) in normal dogs and to assess repeatability of 2D and 3D TTE for the assessment of left ventricular (LV) and left atrial (LA) dimensions.

ANIMALS

The study was performed on six healthy dogs.

MATERIALS AND METHODS

Transthoracic echocardiography, transesophageal echocardiography, CTA, and CMR were performed on each dog. Right ventricular (RV) and LV volumes (in systole and diastole), ejection fraction (EF), and LA and right atrial (RA) volumes were assessed. Repeatability and intrarater and interrater measurements of variability were quantified by average coefficient of variation (CV) for 2D and 3D TTE.

RESULTS

No clinically relevant differences in LV volume were detected between CMR and all modalities. Importantly, 3D TTE had the lowest CV (6.45%), correlated with (r_s = 0.62, p = 0.01), and had the highest overlap in distribution with CMR (OVL >80%). Left ventricular EF and LA size via CTA compared best with CMR and RV and RA volumes were best estimated by 3D TTE. Assessment of LV and LA volumes via 3D TTE had moderate repeatability (15-21%) compared with LV M-mode measurements and 2D LA-to-aortic ratio (<10%), respectively. For LV size, interrater CV for 3D TTE (19.4%) was lower than 2D TTE (23.1%).

CONCLUSIONS

Measurements of LV, RV, and RA volumes via 3D TTE and LA volume and LV EF assessed by CTA compared best with CMR. Three-dimensional echocardiography had lower interrater and intrarater CV compared with 2D TTE.

Artificial cardiac pacemaker placement in dogs with a cohort of myocarditis suspects and association of ultrasensitive cardiac troponin I with survival

INTRODUCTION

Artificial cardiac pacemakers (APs) are a common treatment for symptomatic bradyarrhythmias in dogs, some of which may be triggered by underlying myocarditis. Severely elevated cardiac troponin I (cTnI) concentrations support a diagnosis of myocarditis. The association of ultrasensitive-cTnI (US-cTnI) concentration with survival in a large cohort of dogs receiving APs is not described.

ANIMALS, MATERIALS, AND METHODS

The study included 110 dogs receiving APs over a 5-year period. Medical records were retrospectively reviewed to characterize the entire population receiving APs, with further analysis in dogs with preprocedural US-cTnI concentrations (n = 64) classified as normal/group 1 (n = 11), mildly to moderately elevated/group 2 (n = 27), and severely elevated/myocarditis suspects/group 3 (n = 26).

RESULTS

Median survival time was 1079 days for the entire population, 1167 days for group 2, 949 days for group 3, and not met in group 1. There was not a statistically significant difference in survival between group 2 and group 3. Overall, US-cTnI had a mild, negative association with survival. Age had a stronger negative association. Infectious etiologies were identified in a minority of group 3 cases. A possible association between severely elevated US-cTnI and a sudden death outcome was noted.

CONCLUSIONS

The negative association of US-cTnI with survival outcomes was mild, with age having a larger effect. Although a sudden death outcome may be seen more commonly in myocarditis suspects, group 3 survival time was similar to that of the entire canine population. Plausible infectious causes of myocarditis were infrequently identified.

New Immunocapture Enzyme (ICE) Assay for Quantification of Cancer Procoagulant Activity: Studies of Inhibitors

A new, sensitive and specific immunocapture enzyme (ICE) assay for quantitation of the enzymatic activity of cancer procoagulant (CP) has been developed. The assay had good reproducibility (inter- and intra-assay CV were 6.4% and 5.7% respectively) and was linear for concentrations of CP from 0.5 μg/ml to 10 μg/ml (r2 = 0.995). Using this assay the inhibition of CP by iodoacetamide, mercuric chloride, E-64, leupcptin and antipain was demonstrated. There was no significant effect of cystatin and natural plasma proteinase inhibitors α1-antitrypsin, α1-antichymotrypsin, α2-macroglobulin and antithrombin-III/heparin, on the activity of the CP.

Longitudinal Analysis of Quality of Life, Clinical, Radiographic, Echocardiographic, and Laboratory Variables in Dogs with Preclinical Myxomatous Mitral Valve Disease Receiving Pimobendan or Placebo: The EPIC Study

Background

Changes in clinical variables associated with the administration of pimobendan to dogs with preclinical myxomatous mitral valve disease (MMVD) and cardiomegaly have not been described.

Objectives

To investigate the effect of pimobendan on clinical variables and the relationship between a change in heart size and the time to congestive heart failure (CHF) or cardiac‐related death (CRD) in dogs with MMVD and cardiomegaly. To determine whether pimobendan‐treated dogs differ from dogs receiving placebo at onset of CHF.

Animals

Three hundred and fifty‐four dogs with MMVD and cardiomegaly.

Materials and Methods

Prospective, blinded study with dogs randomized (ratio 1:1) to pimobendan (0.4–0.6 mg/kg/d) or placebo. Clinical, laboratory, and heart‐size variables in both groups were measured and compared at different time points (day 35 and onset of CHF) and over the study duration. Relationships between short‐term changes in echocardiographic variables and time to CHF or CRD were explored.

Results

At day 35, heart size had reduced in the pimobendan group: median change in (Δ) LVIDDN −0.06 (IQR: −0.15 to +0.02), P < 0.0001, and LA:Ao −0.08 (IQR: −0.23 to +0.03), P < 0.0001. Reduction in heart size was associated with increased time to CHF or CRD. Hazard ratio for a 0.1 increase in ΔLVIDDN was 1.26, P = 0.0003. Hazard ratio for a 0.1 increase in ΔLA:Ao was 1.14, P = 0.0002. At onset of CHF, groups were similar.

Conclusions and Clinical Importance

Pimobendan treatment reduces heart size. Reduced heart size is associated with improved outcome. At the onset of CHF, dogs treated with pimobendan were indistinguishable from those receiving placebo.

Relationship between Device Size and Body Weight in Dogs with Patent Ductus Arteriosus Undergoing Amplatz Canine Duct Occluder Deployment

Background

Deployment of the Amplatz Canine Duct Occluder (ACDO) is the preferred method for minimally invasive occlusion of patent ductus arteriosus (PDA) in dogs, with appropriate device sizing crucial to successful closure. Dogs of any body weight can be affected by PDA.

Objectives

To describe the range of ACDO sizes deployed in dogs of various body weights for improved procedural planning and inventory selection and to investigate for correlation between minimal ductal diameter (MDD) and body weight.

Animals

A total of 152 dogs undergoing ACDO deployment between 2008 and 2016.

Methods

Body weight, age, breed, sex, and MDD obtained by angiography (MDD‐A), MDD obtained by transesophageal echocardiography (MDD‐TEE), and ACDO size deployed were retrospectively evaluated.

Results

Correlation between body weight and ACDO size, MDD‐A and MDD‐TEE was poor, with R‐squared values of 0.4, 0.36, and 0.3, respectively. Femoral artery diameter in the smallest population of dogs placed inherent limitations on the use of larger device sizes, with no limitations on the wide range of device sizes required as patient size increased. The most commonly used ACDO devices were size 3 through 6, representing 57% of the devices deployed within the entire study population.

Conclusions and Clinical Importance

Patent ductus arteriosus anatomy varies on an individual basis, with poor correlation between MDD and body weight. Weight‐based assumptions about expected ACDO device size for a given patient are not recommended.

Clinical Characteristics of Adult Dogs More Than 5 Years of Age at Presentation for Patent Ductus Arteriosus

Background

The median age at presentation for dogs with patent ductus arteriosus (PDA) is <6 months of age, and closure is associated with a decrease in heart size and increased survival time, which are not well described in older dogs.

Objectives

To describe the clinical characteristics of dogs with PDA ≥5 years of age at the time of presentation to a veterinary referral hospital.

Animals

35 client‐owned dogs.

Methods

Retrospective case series.

Results

PDA was diagnosed at a median age of 7.4 years (range, 5.1–12.3 years). Females represented 23/35 (65.7%) of the patients. Concurrent heart disease included degenerative mitral valve disease (DMVD; 13), arrhythmias (11), pulmonary hypertension (7), and other congenital defects (2). Cardiomegaly was documented in the majority of dogs consisting of left ventricular enlargement (91%) and left atrial enlargement (86%). Median vertebral heart size in 24 dogs was 12.9 (range, 10.7–18.2). The PDA shunt direction was left‐to‐right in 33 and bidirectional in 2 dogs. Closure was performed in 26 dogs, including 4 with pulmonary hypertension. In 10 dogs receiving furosemide pre‐operatively for management of heart failure, furosemide was discontinued (8) or the dosage decreased (2) at the time of discharge.

Conclusions and Clinical Importance

Adult dogs can present with a left‐to‐right shunting PDA that results in cardiomegaly and clinical signs that can improve or resolve with PDA closure. This improvement is also apparent in dogs with PDA complicated by DMVD. Pulmonary hypertension that does not result in complete right‐to‐left shunting should not be considered a contraindication to closure.

Effect of Pimobendan in Dogs with Preclinical Myxomatous Mitral Valve Disease and Cardiomegaly: The EPIC Study-A Randomized Clinical Trial

Background

Pimobendan is effective in treatment of dogs with congestive heart failure (CHF) secondary to myxomatous mitral valve disease (MMVD). Its effect on dogs before the onset of CHF is unknown.

Hypothesis/Objectives

Administration of pimobendan (0.4–0.6 mg/kg/d in divided doses) to dogs with increased heart size secondary to preclinical MMVD, not receiving other cardiovascular medications, will delay the onset of signs of CHF, cardiac‐related death, or euthanasia.

Animals

360 client‐owned dogs with MMVD with left atrial‐to‐aortic ratio ≥1.6, normalized left ventricular internal diameter in diastole ≥1.7, and vertebral heart sum >10.5.

Methods

Prospective, randomized, placebo‐controlled, blinded, multicenter clinical trial. Primary outcome variable was time to a composite of the onset of CHF, cardiac‐related death, or euthanasia.

Results

Median time to primary endpoint was 1228 days (95% CI: 856–NA) in the pimobendan group and 766 days (95% CI: 667–875) in the placebo group (P = .0038). Hazard ratio for the pimobendan group was 0.64 (95% CI: 0.47–0.87) compared with the placebo group. The benefit persisted after adjustment for other variables. Adverse events were not different between treatment groups. Dogs in the pimobendan group lived longer (median survival time was 1059 days (95% CI: 952–NA) in the pimobendan group and 902 days (95% CI: 747–1061) in the placebo group) (P = .012).

Conclusions and Clinical Importance

Administration of pimobendan to dogs with MMVD and echocardiographic and radiographic evidence of cardiomegaly results in prolongation of preclinical period and is safe and well tolerated. Prolongation of preclinical period by approximately 15 months represents substantial clinical benefit.

Relationship of plasma N-terminal pro-brain natriuretic peptide concentrations to heart failure classification and cause of respiratory distress in dogs using a 2nd generation ELISA assay

Background

Cardiac biomarkers provide objective data that augments clinical assessment of heart disease (HD).

Hypothesis/Objectives

Determine the utility of plasma N‐terminal pro‐brain natriuretic peptide concentration [NT‐proBNP] measured by a 2nd generation canine ELISA assay to discriminate cardiac from noncardiac respiratory distress and evaluate HD severity.

Animals

Client‐owned dogs (n = 291).

Methods

Multicenter, cross‐sectional, prospective investigation. Medical history, physical examination, echocardiography, and thoracic radiography classified 113 asymptomatic dogs (group 1, n = 39 without HD; group 2, n = 74 with HD), and 178 with respiratory distress (group 3, n = 104 respiratory disease, either with or without concurrent HD; group 4, n = 74 with congestive heart failure [CHF]). HD severity was graded using International Small Animal Cardiac Health Council (ISACHC) and ACVIM Consensus (ACVIM‐HD) schemes without knowledge of [NT‐proBNP] results. Receiver‐operating characteristic curve analysis assessed the capacity of [NT‐proBNP] to discriminate between dogs with cardiac and noncardiac respiratory distress. Multivariate general linear models containing key clinical variables tested associations between [NT‐proBNP] and HD severity.

Results

Plasma [NT‐proBNP] (median; IQR) was higher in CHF dogs (5,110; 2,769–8,466 pmol/L) compared to those with noncardiac respiratory distress (1,287; 672–2,704 pmol/L; P < .0001). A cut‐off >2,447 pmol/L discriminated CHF from noncardiac respiratory distress (81.1% sensitivity; 73.1% specificity; area under curve, 0.84). A multivariate model comprising left atrial to aortic ratio, heart rate, left ventricular diameter, end‐systole, and ACVIM‐HD scheme most accurately associated average plasma [NT‐proBNP] with HD severity.

Conclusions and Clinical Importance

Plasma [NT‐proBNP] was useful for discriminating CHF from noncardiac respiratory distress. Average plasma [NT‐BNP] increased significantly as a function of HD severity using the ACVIM‐HD classification scheme.

Long-term outcome in dogs with patent ductus arteriosus: 520 cases (1994-2009)

Background

Published information regarding survival and long‐term cardiac remodeling after patent ductus arteriosus (PDA) closure in dogs is limited.

Objectives

To report outcome and identify prognostic variables in dogs with PDA, and to identify risk factors for persistent remodeling in dogs with a minimum of 12 months of follow‐up after closure.

Animals

Five hundred and twenty client‐owned dogs.

Methods

Retrospective review of medical records of 520 dogs with PDA. Outcome was determined by contacting owners and veterinarians. Dogs with PDA closure and ≥ 12 months of follow‐up were asked to return for a re‐evaluation.

Results

In multivariable analysis of 506 dogs not euthanized at the time of diagnosis, not having a PDA closure procedure negatively affected survival (HzR = 16.9, P < .001). In 444 dogs undergoing successful PDA closure, clinical signs at presentation (HzR = 17, P = .02), concurrent congenital heart disease (HD) (HzR = 4.8, P = .038), and severe mitral regurgitation (MR) documented within 24 hours of closure (HzR = 4.5, P = .028) negatively affected survival. Seventy‐one dogs with ≥ 12 months follow‐up demonstrated a significant reduction in radiographic and echocardiographic measures of heart size (P = 0) and increased incidence of acquired HD (P = .001) at re‐evaluation. Dogs with increased left ventricular size and low fractional shortening at baseline were more likely to have persistent remodeling at re‐evaluation.

Conclusions and Clinical Importance

Patent ductus arteriosus closure confers important survival benefits and results in long‐term reverse remodeling in most dogs. Clinical signs at presentation, concurrent congenital HD, and severe MR negatively affect survival. Increased left ventricular systolic dimensions and systolic dysfunction at baseline correlated significantly with persistent remodeling.

Bradyarrhythmias and pacemaker therapy in dogs with Chagas disease

BACKGROUND

Chagas disease (Trypanosomiasis) is a cause of myocarditis in the southern United States causing cardiac conduction abnormalities, arrhythmias, and heart failure.

OBJECTIVES

To report clinical findings and outcome in Chagas positive (CP) dogs requiring pacemaker implantation for bradyarrhythmias.

ANIMALS

One hundred and forty-four client-owned dogs requiring pacemaker implantation.

METHODS

Retrospective case series. Information regarding history, physical exam, laboratory and diagnostic imaging findings, treatment, and survival were obtained from medical records, with additional follow-up information obtained by contacting referring veterinarians and owners.

RESULTS

Of the 144 dogs requiring pacemaker implantation from January 2001 to May 2010, 83 (57.6%) had a Chagas titer performed and 9 (10%) were CP. Concurrent ventricular arrhythmias (odds ratio 1.61, P = .005) or atrioventricular (AV) block (odds ratio 4.18, P < .001) increased the likelihood that a Chagas titer was submitted. Median age for CP dogs was 6.2 years (range, 0.3-10); 7 were male. Bradyarrhythmias included high-grade 2nd or 3rd degree AV block (n = 8) and sinus bradycardia with 1st degree AV block (n = 1); 5 had concurrent ventricular arrhythmias. A positive Chagas titer had a negative impact on survival (hazard ratio 4.04; 95% CI 1.36-12.1, P = .012) with a reported median survival time of 365 days (interquartile range, 84-973 days).

CONCLUSIONS AND CLINICAL IMPORTANCE

Bradyarrhythmias can result in clinical signs requiring pacemaker implantation in CP dogs, and although the diagnosis negatively impacts survival, pacemaker therapy is a viable treatment option.

Efficacy of pimobendan in the prevention of congestive heart failure or sudden death in Doberman Pinschers with preclinical dilated cardiomyopathy (the PROTECT Study)

BACKGROUND

The benefit of pimobendan in delaying the progression of preclinical dilated cardiomyopathy (DCM) in Dobermans is not reported.

HYPOTHESIS

That chronic oral administration of pimobendan to Dobermans with preclinical DCM will delay the onset of CHF or sudden death and improve survival.

ANIMALS

Seventy-six client-owned Dobermans recruited at 10 centers in the UK and North America.

METHODS

The trial was a randomized, blinded, placebo-controlled, parallel group multicenter study. Dogs were allocated in a 1:1 ratio to receive pimobendan (Vetmedin capsules) or visually identical placebo. The composite primary endpoint was prospectively defined as either onset of CHF or sudden death. Time to death from all causes was a secondary endpoint.

RESULTS

The proportion of dogs reaching the primary endpoint was not significantly different between groups (P = .1). The median time to the primary endpoint (onset of CHF or sudden death) was significantly longer in the pimobendan (718 days, IQR 441-1152 days) versus the placebo group (441 days, IQR 151-641 days) (log-rank P = 0.0088). The median survival time was significantly longer in the pimobendan (623 days, IQR 491-1531 days) versus the placebo group (466 days, IQR 236-710 days) (log-rank P = .034).

CONCLUSION AND CLINICAL IMPORTANCE

The administration of pimobendan to Dobermans with preclinical DCM prolongs the time to the onset of clinical signs and extends survival. Treatment of dogs in the preclinical phase of this common cardiovascular disorder with pimobendan can lead to improved outcome.

Prospective evaluation of NT-proBNP assay to detect occult dilated cardiomyopathy and predict survival in Doberman Pinschers

BACKGROUND

Occult (asymptomatic) dilated cardiomyopathy (ODCM) is highly prevalent in Doberman Pinschers.

HYPOTHESIS/OBJECTIVES

Assess ability of NT-proBNP assay to detect ODCM and predict death.

ANIMALS

155 asymptomatic Dobermans presenting for ODCM screening.

METHODS

Echocardiography, 24-hour Holter, and NT-proBNP assay were performed prospectively. Diagnosis was based on increased left ventricular end-systolic dimension, >50 ventricular premature complexes (VPCs), or both on Holter. Utility was evaluated using receiver-operating characteristic curves. Effect of age, weight, sex, disease status, VPCs, and NT-proBNP on survival was analyzed using Kaplan-Meier and Cox-proportional hazard analysis.

RESULTS

Seventy-three (47.1%) Dobermans were diagnosed with ODCM, including 31, 17, and 25 that met Holter, echocardiographic, or both criteria, respectively. Sensitivity of NT-proBNP > 457 pmol/L to detect these groups was 45.2, 76.5, and 96.0%, respectively. Combination of NT-proBNP and Holter to detect ODCM yielded sensitivity of 94.5%, specificity of 87.8%, and accuracy of 91.0%. Follow-up data were available for 78 Dobermans. The median survival time of Dobermans with > 50 VPCs (469 days), NT-proBNP > 900 pmol/L (284 days), or ODCM (474 days) was significantly (P < .0001) shorter than those with < 50 VPCs (1743 days), NT-proBNP < 900 pmol/L (1743 days), or without disease (1743 days). NT-proBNP concentration and disease status were independently predictive of all-cause mortality.

CONCLUSIONS AND CLINICAL IMPORTANCE

The combination of NT-proBNP assay and Holter detected ODCM with high accuracy. NT-proBNP and disease status were independently associated with survival. NT-proBNP assay identified Dobermans with high probability of increased LVIDs consistent with ODCM, and can facilitate pursuit of confirmatory diagnostic testing, such as echocardiography, in suspected Dobermans.

Molecular Marker Analysis of Soybean Plant Introductions with Resistance to Phytophthora sojae

ABSTRACT Molecular analysis of sources of resistance to plant pathogens should expedite and confirm novel gene discovery and consequently the development of disease resistant cultivars. Recently, soybean plant introductions (PIs) were identified that contain putative novel Rps genes for resistance to Phytophthora sojae. The number of resistance genes that confer resistance to P. sojae isolates OH17 (1b,1d,2,3a,3b,3c,4,5,6,7) and OH25 (1a,1b,1c,1k,7) was then determined in several of the PIs. The objective of this study was to determine if the Rps genes present in these PIs were associated with eight described Rps loci that have been mapped on soybean molecular linkage groups F, G, J, and N. Nine F(2:3) soybean populations were genotyped with simple sequence repeat (SSR) markers linked to previously mapped Rps loci. The nine PI populations all had SSR markers associated (P < 0.01) with resistance to P. sojae isolate OH17 in the Rps1 region. Rps1c is a likely candidate in eight PIs but novel genes may also be possible, while novel genes may confer resistance in one PI to P. sojae isolate OHI7. Two or more Rps genes, including some that are potentially novel, confer resistance to P. sojae isolate OH25 in eight of the populations. However, based on the response to these two isolates, virulence already exists for at least some of the novel genes identified in this study.

Phytophthora genome sequences uncover evolutionary origins and mechanisms of pathogenesis

Draft genome sequences have been determined for the soybean pathogen Phytophthora sojae and the sudden oak death pathogen Phytophthora ramorum. Oömycetes such as these Phytophthora species share the kingdom Stramenopila with photosynthetic algae such as diatoms, and the presence of many Phytophthora genes of probable phototroph origin supports a photosynthetic ancestry for the stramenopiles. Comparison of the two species' genomes reveals a rapid expansion and diversification of many protein families associated with plant infection such as hydrolases, ABC transporters, protein toxins, proteinase inhibitors, and, in particular, a superfamily of 700 proteins with similarity to known oömycete avirulence genes.

Heritability and Components of Resistance to Cercospora zeae-maydis Derived from Maize Inbred VO613Y

ABSTRACT Gray leaf spot (GLS), caused by the fungus Cercospora zeae-maydis, is one of the most important foliar diseases of maize. This study was undertaken to estimate heritability of C. zeae-maydis resistance and examine the relationship between previously identified resistance loci and certain components of resistance including incubation period, lesion number, and maximum lesion length. Partially inbred progenies arising from hybridization between maize inbred lines VO613Y (high level of partial resistance) and Pa405 (susceptible) were examined in Ohio and South Africa. Heritability estimates of resistance were calculated based on severity and incubation period values. The range of heritability estimates based on severity was broad, with values ranging from approximately 0.46 to 0.81 (mean = 0.59). Estimates of mean heritability for incubation period were lowest (0.18), indicating that this component would likely be unsuitable for selection of germ plasm intended for deployment in diverse regions. Length of GLS lesions was significantly affected by host genotype, with resistant genotypes having shorter lesions from one site in Ohio during two seasons. Genotype also had a significant effect on incubation period and lesion number; the lower values for these components also were associated with resistant genotypes. The combined action of these resistance components resulted in lower overall disease severity.

Transarterial coil embolization for canine patent ductus arteriosus occlusion

Left to right shunting patent ductus arteriosus (PDA) is the most common canine congenital heart defect. If not occluded PDA is associated with high morbidity and mortality. Historically, surgical ligation has been the standard method of correction. Although highly successful, surgical ligation is associated with some operative morbidity and mortality. More recently, minimally invasive transcatheter techniques have been employed for PDA occlusion. Transarterial PDA coil embolization is a safe, cost effective, less invasive alternative offered by many specialty centers for PDA occlusion. This procedure involves catheterization of the femoral artery under general anesthesia. An angiogram is then performed to delineate PDA morphology and facilitate coil selection. Coils are commercially available and composed of surgical stainless steel with prothrombotic poly-Dacron fibers. Coils are advanced through a catheter into the PDA under fluoroscopic guidance until satisfactory angiographic occlusion is documented. Patients are then recovered and released the following day. This procedure requires substantial technical expertise and specialized equipment.

Properties of proteins in cancer procoagulant preparations that are detected by anti-tissue factor antibodies

Cancer procoagulant (CP) and tissue factor (TF; only in complex with Factor VIIa (FVIIa)) can activate FX to FXa. Controversy still exists whether or not CP is an entity different from TF, or whether CP activity is due to contamination of CP preparations with TF/FVIIa complex. We therefore looked for proteins in CP preparations that were detected by anti-TF antibodies and then sequenced these proteins. One- and two-dimensional gels of CP and TF were used to identify proteins immunoreactive to monoclonal anti-CP and anti-TF antibodies (Mabs). Those proteins in the CP preparation recognized by anti-TF antibodies were sequenced. Angiotensinogen precursor, alpha-1-antitrypsin precursor, and vitamin D-binding protein were identified along with one so far unidentified sequence; however, no TF-sequences were identified. Also, no proteins with the correct molecular weight for TF were identified using anti-TF antibodies. It seems possible that CP preparations contain proteins that have some epitopes similar to the epitopes recognized in TF by anti-TF Mab. However, these proteins do neither have the molecular weight nor the amino acid sequence of TF.

Update on tumor cell procoagulant factors

Tumor cells produce tissue factor, cancer procoagulant, plasminogen activators and other factors that interact with the coagulation system, the fibrinolytic system and vascular or blood cells such that they can upset the normal homeostasis and balance between activation and inhibition of the coagulation and fibrinolytic systems. These activities play a role in tumor cell growth and metastasis, vascular wall function, and hemostasis. Proteases and their inhibitors are intimately involved in all aspects of the hemostatic, cell proliferation and cellular signalling systems. This review provides a brief examination of recent observations in this complex interaction of cellular and hemostatic factors.

Removing barriers and improving choices: a case study in reproductive health services and managed care

Managed care contains inherent structural features that can create obstacles to time-sensitive, confidential reproductive health services. Such structural impediments often exacerbate the sociocultural barriers that have historically affected low-income women--the population that has been targeted for mandatory enrollment in Medicaid managed care plans in many states. This article recommends public policy strategies to overcome and prevent multiple barriers that were identified in a New York-based study in 1995, which focused on access to reproductive health services in managed care settings. This article also includes updated evidence supporting the study's findings and its relevance to other states.

Cancer procoagulant and tissue factor are differently modulated by all-trans-retinoic acid in acute promyelocytic leukemia cells

All-trans-retinoic acid (ATRA) downregulates the expression of two cellular procoagulants, tissue factor (TF) and cancer procoagulant (CP), in human promyelocytic leukemia cells. To evaluate whether or not changes of the procoagulant activities (PCAs) may share mechanisms with the ATRA-induced cyto-differentiation process, we have characterized the effect of ATRA on the TF and CP expression by NB4 cells, an ATRA maturation-inducible cell line, and two NB4-derived cell lines resistant to ATRA-induced maturation, the NB4. 306 and NB4.007/6 cells. Next, we evaluated the effect on the PCAs of the NB4 parental cells of three synthetic retinoid analogues, ie: AM580 (selective for the retinoic acid receptor [RAR] alpha), capable to induce the granulocytic differentiation of NB4 cells; and CD2019 (selective for RARbeta) and CD437 (selective for RARgamma), both lacking this capability. Cells were treated with either ATRA or the analogues (10(-6) to 10(-8) mol/L) for 96 hours. The effect on cell differentiation was evaluated by morphologic changes, cell proliferation, nitro blue tetrazolium reduction assay, and flow cytometry analysis of the CD33 and CD11b surface-antigen expression. PCA was first measured in 20 mmol/L Veronal Buffer cell extracts by the one-stage clotting assay of normal and FVII-deficient plasmas. Further TF and CP have been characterized and quantified in cell-sample preparations by chromogenic and immunological assays. In the first series of experiments, ATRA downregulates both TF and CP in NB4 parental cells, as expected. However, in the differentiation-resistant cell lines, it induced a significant loss of TF but had little or no effect on CP. In a second series of experiments, in the NB4 parental cells, the RARalpha agonist (AM580) induced cell maturation and reduced 91% CP expression, whereas CD437 and CD2019 had no cyto-differentiating effects and did not affect CP levels. On the other hand, in the same cells the TF expression was reduced by ATRA and AM580, but also by the RARbeta agonist CD2019, which did not induce cell maturation. These data indicate that in NB4 cells, ATRA modulation of CP occurs in parallel with signs of cell differentiation, while the regulation of TF appears to be at least in part independent from these processes, and involves both alpha and beta nuclear retinoid receptors.

Cancer procoagulant: a factor X activator, tumor marker and growth factor from malignant tissue

Hemostatic abnormalities associated with malignant disease led to the search for and discovery of a proteolytic enzyme that activated factor X in the blood coagulation cascade. It was named cancer procoagulant (CP). CP is a cysteine proteinase that is found in malignant and fetal (human amnion-chorion) tissue; it has not been found in normally differentiated tissue. It is a calcium-dependent, Mn2+ stimulated enzyme that has enhanced activity and inhibition in a reduced environment. This review presents a complete compilation and discussion of the known chemical and enzymatic characteristics of CP as well as many purification and assay procedures. Several unique properties of these procedures are described. Some problems and controversies are highlighted in each of the sections. An immunoassay for CP as a tumor marker and some of its potential applications in the diagnosis and monitoring of cancer are reviewed. Some therapeutic implications of CP are noted in light of the observation that antibodies to CP block the metastatic seeding of lung colonies in vivo and diminish the viability of tumor cells in vitro. Finally, comments about the relationship between tissue factor and CP in the malignant cells are provided.

Enhanced isolated lung function after ischemia with anti-intercellular adhesion molecule antibody

The binding of leukocytes to intercellular adhesion molecules expressed on endothelial surfaces during ischemia and subsequent reperfusion initiates leukocyte-mediated reperfusion injury. Interruption of this leukocyte-endothelium interaction may therefore prevent reperfusion injury. In an isolated, ventilated, blood-perfused rabbit lung preparation, we studied the effect of a monoclonal anti-intercellular adhesion molecule antibody on lung function during reperfusion. Lungs were harvested with 50 ml/kg cold Euro-Collins flush and 30 micrograms prostaglandin E1 before storage for 18 hours at 4 degrees C. Experimental groups received low-dose (100 micrograms) or high-dose (200 micrograms) anti-intercellular adhesion molecule antibody added to the pulmonary flush at harvest and to the initial reperfusate. Eighteen-hour control preparations were preserved for 18 hours and received saline solution vehicle. Immediate control preparations were harvested and immediately reperfused. The oxygen tension in the recirculated pulmonary venous effluent was measured after 30 minutes of reperfusion. Histologic specimens were graded by blinded observers for degree of leukocyte infiltration (0, normal, to 4, severe infiltration). The mean oxygen tensions (+/-standard error of the mean) were 138.29 +/- 6.23, 58.86 +/- 9.14, 86.87 +/- 11.32, and 139.33 +/- 16.15 mm Hg in immediate control preparations, 18-hour control preparations, low-dose antibody group, and high-dose antibody group, respectively (p = 0.0001). The leukocyte grades (mean +/- standard error of the mean) were 1.5 +/- 0.723, 3.0 +/- 0.955, 1.9 +/- 0.899, and 1.2 +/- 0.834, respectively (p = 0.0002). We conclude that anti-intercellular adhesion molecule antibody added to the pulmonary flush and initial reperfusate results in a dose-dependent enhancement of the reperfused lung's ability to oxygenate blood, possibly as a result of decreased leukocyte sequestration.

Effect of divalent ions on the activity of cancer procoagulant

The effect of calcium (Ca2+), magnesium (Mg2+), manganese (Mn2+), iron (Fe2+), and zinc (Zn2+) on the factor X-activating activity of cancer procoagulant (CP) was studied. Activity of CP was evaluated with a three-stage chromogenic assay (liquid-phase assay, "native" CP) and with an immunocapture enzyme (ICE) assay (solid-phase assay, immobilized CP). In the liquid-phase assay, CP activity was Ca(2+)-dependent, and Mg2+ (5 mM) or Mn2+ (0.01-0.1 mM) could substitute for Ca2+. There was no additive effect of Mg2+ and Ca2+ on the activity of CP. Activity of CP in the liquid-phase assay, in the presence of 7 mM Ca2+, was enhanced by 0.1 mM Mn2+ to about 240% of the activity observed when only Ca2+ was present in the reaction. Zn2+ and Fe2+ did not activate CP in the absence of Ca2+; they inhibited CP activity in a concentration-dependent mode when administered in the presence of Ca2+. The activity of CP evaluated by the solid-phase assay (ICE assay) was neither Ca(2+)-dependent nor was it susceptible to potentiation by Mn2+ administered after CP was bound to IgM. CP exposed to 5 mM Mn2+ before binding to IgM expressed about 85% higher activity than without the presence of Mn2+. When CP was first preincubated with divalent ion and then immunocaptured, the signal generated in the enzyme-linked immunoadsorbent assay by Mn(2+)-containing CP was significantly different (30% greater) than signals generated by CP without Mn2+ or containing different ion. These data suggest that: (1) there is a significant conformational change of the CP molecule that takes place after capturing CP by the monoclonal IgM antibody on the solid surface; (2) the divalent ions are not directly involved in enzyme-substrate interactions in the CP moiety; and (3) the interaction of Mn2+ with CP seems to be different from that of the other divalent ions.

Application of cancer procoagulant as an early detection tumor marker

BACKGROUND

In spite of many advances in the analytical reagents (antibodies), analytical systems, and the clinical application of tumor markers, the present markers do not detect early stage cancer. Preliminary data with an antigen specific to tumor tissue, cancer procoagulant (CP), suggest its possible role in the detection of early stage cancer. This study was aimed at determining the clinical use of CP as an early stage tumor marker.

METHODS

An improved enzyme-linked immunosorbent assay (ELISA) was developed to measure CP concentration in serum. A panel of 817 blinded serum samples were examined from three groups of people: 573 cancer, 106 benign, and 139 normal.

RESULTS

The sensitivity of all samples analyzed from cancer patients was 80%. The CP ELISA was able to detect ovarian, colon, and kidney cancer at a sensitivity greater than 85%; breast, prostate and small cell lung cancer was detected at a sensitivity of 80-85%. Particularly interesting was the observation that early stage cancers, regardless of site, were detected effectively. In some groups, the CP assay correctly identified 100% of the patients with stage I and II cancer. The assay was able to identify correctly noncancer patient sera at a specificity of 83% for those with benign disease and 82% for the normal individuals.

CONCLUSIONS

The CP assay has potential as an aid in diagnosing early stage malignancies and thereby may significantly improve the survival rate of cancer patients.

Reduced expression of glutathione S-transferase Yb2 during progression of chemically induced hepatocellular carcinomas in Fischer 344 rats

We followed the expression of several glutathione S-transferase subunits in altered foci, liver neoplasms and metastases produced in male Fischer 344 rats by a modified Solt-Farber protocol, to determine whether components of the resistant phenotype are lost during neoplastic progression. At 6 mo after initiation, altered foci and persistent nodules displayed increased immunohistochemical expression of glutathione S-transferase subunits Yf (pi-class), Ya (alpha-class) and Yb1 (mu-class) in comparison with normal or surrounding liver tissue. However, although most altered foci exhibited little change in glutathione S-transferase Yb2 (mu-class) subunit expression, 5% of Yf-positive foci and nodules were partially or completely deficient in Yb2 expression. At 12 and 18 mo after initiation, most grossly visible hepatocellular tumors retained induced expression of glutathione S-transferase subunits Yf, Ya and Yb1, but 63% of the carcinomas, 88% of the primary metastatic carcinomas and 94% of the pulmonary metastases were deficient in Yb2 expression. These differences in glutathione S-transferase subunit expression were confirmed by quantitative analysis by reverse-phase HPLC of S-hexylglutathione affinity-purified glutathione S-transferases from advanced tumors. Cytosolic glutathione S-transferase activity for trans-4-phenyl-3-buten-2-one in advanced tumors ranged from 42% to 66% of the activity in matched surrounding liver, whereas glutathione S-transferase activities for 1-chloro-2,4-dinitrobenzene were increased by 140% to 161%. These studies demonstrate that progression of hepatocellular carcinomas in the resistant hepatocyte model of carcinogenesis in which several glutathione S-transferase subunits are induced is associated with the loss of a major constitutive mu-class hepatic glutathione S-transferase. Although the mechanism and role of the reduction or loss of glutathione S-transferase Yb2 during malignant progression are unknown, we propose that loss of glutathione S-transferase Yb2 in some preneoplastic populations of hepatocytes might be conducive to further DNA damage by presently unknown environmental or endogenous compounds that are normally detoxified preferentially by glutathione S-transferase isoenzymes containing this subunit.

New immunocapture enzyme (ICE) assay for quantification of cancer procoagulant activity: studies of inhibitors

A new, sensitive and specific immunocapture enzyme (ICE) assay for quantitation of the enzymatic activity of cancer procoagulant (CP) has been developed. The assay had good reproducibility (inter- and intra-assay CV were 6.4% and 5.7% respectively) and was linear for concentrations of CP from 0.5 microgram/ml to 10 micrograms/ml (r2 = 0.995). Using this assay the inhibition of CP by iodoacetamide, mercuric chloride, E-64, leupeptin and antipain was demonstrated. There was no significant effect of cystatin and natural plasma proteinase inhibitors alpha 1-antitrypsin, alpha 1-antichymotrypsin, alpha 2-macroglobulin and antithrombin-III/heparin, on the activity of the CP.

A structured literature review for risk assessment: EMF and human health risk

The volume of publications on any given topic makes it difficult to select an appropriate subset of publications for review by an expert panel. This paper proposes a method for selecting a subset using a protocol that attempts to order publications based upon good research methods. The protocol was followed by graduate students with no expert knowledge of the area they were reviewing. They reduced 11730 articles on the topic of EMF and Health risk to 68 articles that were reviewed by an expert panel. The interrater reliability was 96% and 94% of the relevant articles were captured by this process.

Cancer procoagulant

Cancer procoagulant is a unique cysteine proteinase. The enzyme has been purified by several procedures and many of its characteristics and enzymatic properties have been determined. Several sensitive and reproducible assays are now available. Many proteinase inhibitors have been evaluated for their effect on CP; most low molecular weight inhibitors work well in a reduced environment. In the foreseeable future, protein and gene sequence information, expression vectors, molecular probes, and highly specific antibodies and inhibitors should provide the research tools to delineate a functional understanding of CP at the molecular and cellular level.

Cancer procoagulant in the human promyelocytic cell line NB4 and its modulation by all-trans-retinoic acid

Acute promyelocytic leukemia (APL) cells express different types of procoagulant activity (PCA), including tissue factor (TF), and cancer procoagulant (CP). The aim of this study was to investigate whether the NB4 cell line, the first ever isolated human APL line, with the typical t(15;17) chromosomal balance translocation, possess CP as well as the cells freshly isolated from APL patients. Secondly, since the NB4 line is maturation inducible by all-trans-retinoic acid (ATRA), we wanted to verify whether CP, if present, was affected by ATRA treatment. The NB4 cells were able to shorten the recalcification assay of normal human plasma (total PCA). To distinguish CP in the assay for clotting activity, two criteria were used, the independence from factor VII to trigger blood coagulation and the sensitivity to cysteine proteinase inhibitors. Forty-seven per cent of total PCA of cell extracts was found to be FVII-independent PCA. A similar proportion of FVII-independent activity (42%) was detected in the cell serum-free supernatants. The activity was significantly decreased by cysteine proteinase inhibitors, including HgCl2, lodoacetic acid and Z-Ala-AlaCHN2. Additionally CP was directly identified and quantified by an immunocapture enzyme assay. The mean +/- SD concentration of CP detected by this assay in the NB4 cells, before any treatment, was 1.89 +/- 0.5 microgram/mg protein. Treatment of NB4 cells with 10(-6) M ATRA for 5 days significantly decreased the expression of CP, which became virtually undetectable by the clotting assay, and was 64% less than the untreated control by the immunocapture enzyme assay. This study provides the first evidence that the human promyelocytic cell line NB4 possess CP. The expression of this procoagulant is modulated by ATRA.

Three-stage chromogenic assay for the analysis of activation properties of factor X by cancer procoagulant

The cysteine proteinase, cancer procoagulant (CP; EC 3.4.22.26) was isolated from human amnion-chorion and purified by precipitation with polyethylene glycol and either ion exchange or immunoaffinity chromatography. A new, sensitive, three-stage chromogenic assay was developed for determination of CP factor X-activating activity. Using this assay some properties including dose-response, effect of calcium, phospholipid and pH on the activation of factor X by CP was determined. There was an excellent linear correlation (r2 = 0.99) between concentration and the enzymatic activity of CP. The activation of factor X by purified CP was calcium dependent with an optimum calcium concentration of 7 mM. CP was not phospholipid dependent. There was a rather broad pH optimum between pH 6.9 and 7.25 for the activation of factor X by CP.

Cancer cell procoagulants and their implications

Cancer cells induce abnormal blood coagulation through a process that probably involves a combination of increased activators and deficiencies of anticoagulants. The probable participating factors (including tissue factor-factor VII and cancer procoagulant) and their role in this process are discussed. The current theory on the role of coagulation in malignant disease is also discussed.

The site of activation of factor X by cancer procoagulant

Cancer procoagulant (CP) is a cysteine proteinase found in a variety of malignant cells and tissues and in human amnion-chorion tissue. It initiates coagulation by activating factor X. However, the amino acid sequence of the substrate protein that determines the cleavage site of cysteine proteinases is different from that of the serine proteinases that normally activate factor X, such as factor IXa, VIIa and Russell's Viper Venom (RVV). Therefore, it was of interest to determine the site of cleavage of human factor X by CP. Purified CP was incubated with purified factor X and the reaction mixture was electrophoresed on a 10% Tris-tricine SDS-PAGE gel. The proteins were electroeluted on to a polyvinylidene difluoride (PVDF) membrane, and stained with Coomassie blue. The heavy chain of activated factor X was cut out of the PVDF membrane and sequenced with an Applied Biosystems 477A with on-line HPLC. The primary cleavage sequence was Asp-Ala-Ala-Asp-Leu-Asp-Pro-; two other secondary sequences Ser-Ile-Thr-Trp-Lys-Pro- and Glu-Asn-Pro-Phe-Asp-Leu were found. The penultimate amino acid on the carbonyl side of the hydrolysed amide bond plays a critical role for the recognition of the cleavage site of cysteine proteinases. These data indicate that the penultimate amino acid for the primary cleavage site of factor X by CP is proline-20 and for the secondary sites, proline-13 and proline-28. This is in contrast to arginine-52 that determines the specificity of the cleavage by normal serine proteinase activation.(ABSTRACT TRUNCATED AT 250 WORDS)

An enzyme-linked immunosorbent assay for cancer procoagulant and its potential as a new tumor marker

Cancer procoagulant (CP) is a Mr 68,000 cysteine proteinase that initiates blood coagulation and is expressed by a variety of malignant cells but not by normally differentiated cells. Polyclonal immunoglobulin G and monoclonal immunoglobulin M antibodies were developed to purified CP and used to develop an enzyme-linked immunosorbent assay to analyze the antigen in human serum samples. The purpose of this preliminary study was to determine whether or not the analysis of CP in the serum might be a useful tumor marker. Pure CP was added to normal serum to establish a quantitative standard curve; the correlation coefficient of seven standard curves was 0.99. The upper limit of the normal range was established with 46 normal sera (mean +/- 2 SD = 0.57 microgram/ml). A total of 128 blinded serum samples were analyzed: 54 were from cancer patients (29 with gastrointestinal cancer, 22 with lung cancer, and three with urogenital cancer); 20 were from benign disease patients; and 54 were from normal individuals. All of the 13 early stage cancers were greater than 0.57 microgram/ml (positive), 31 of 41 (76%) of the late stage cancers were positive; overall, 44 of the 54 cancers (81%) were positive. Forty-nine of 54 (91%) of the normal sera and 16 of 20 (80%) of the benign disease sera were negative. Overall, the assay had a sensitivity of 81% and a specificity of 88%.

Analysis of serum cancer procoagulant activity and its possible use as a tumor marker

The two objectives of the study were to determine whether a procedure could be developed for measuring cancer procoagulant (CP) activity in human serum and if this procedure provided a method for distinguishing people with cancer from those without cancer. A procedure was developed for processing human serum such that the activity of other coagulation enzymes would be minimized and the activity of cancer procoagulant could be measured. In a blinded study, we collected serum from 61 individuals in serum separator tubes, removed the clot by centrifugation, extracted the serum with a simple, single step procedure and analyzed the extract for CP activity. The results indicate that this test could correctly identify about 92% of the cancer patient serum samples and about 75% of the non-cancer patients serum samples, for an overall accuracy of about 85%.

Cancer procoagulant in human tumor cells: evidence from melanoma patients

It has repeatedly been proposed that fibrin plays a role in tumor growth and metastasis. Among tumor cell products or activities which may promote clot formation, cancer procoagulant (CP), a direct activator of coagulation factor X, has been suggested to be selectively associated with the malignant phenotype. We report here the enzymatic and immunological identification of this cysteine proteinase procoagulant in extracts and cells from human melanoma. CP activity was independent of both the intrinsic and extrinsic pathways of blood coagulation, using factor IX and factor VII deficient plasmas, and was inhibited by the cysteine proteinase inhibitors iodoacetamide and HgCl2. CP activity was detectable in extracts and cell suspensions from all 32 patients studied and was higher in extracts from metastases (14.8 +/- 3.9 units/mg protein) than from the primary tumors (3.7 +/- 1.0 units/mg protein). CP activity was not affected by an anti-apoprotein III antibody or by concanavalin A, a known inhibitor of thromboplastin. In contrast, no CP activity or antigen was detected in extracts from six benign melanocytic lesions. The procoagulant activity was dependent on factor VII and was inhibited by anti-apoprotein III antibody and by concanavalin A, properties that suggest that the procoagulant was tissue thromboplastin. These data indicate that CP can be expressed by human tumor cells and that, among melanotic lesions, its presence is associated with the malignant phenotype and its activity is particularly high in metastatic cells.