Acute Coronary Syndrome Subphenotypes Based on Repeated Biomarker Measurements in Relation to Long-Term Mortality Risk.

BACKGROUND: We aimed to identify patients with subphenotypes of postacute coronary syndrome (ACS) using repeated measurements of high-sensitivity cardiac troponin T, N-terminal pro-B-type natriuretic peptide, high-sensitivity C-reactive protein, and growth differentiation factor 15 in the year after the index admission, and to investigate their association with long-term mortality risk. METHODS AND RESULTS: BIOMArCS (BIOMarker Study to Identify the Acute Risk of a Coronary Syndrome) was an observational study of patients with ACS, who underwent high-frequency blood sampling for 1 year. Biomarkers were measured in a median of 16 repeated samples per individual. Cluster analysis was performed to identify biomarker-based subphenotypes in 723 patients without a repeat ACS in the first year. Patients with a repeat ACS (N=36) were considered a separate cluster. Differences in all-cause death were evaluated using accelerated failure time models (median follow-up, 9.1 years; 141 deaths). Three biomarker-based clusters were identified: cluster 1 showed low and stable biomarker concentrations, cluster 2 had elevated concentrations that subsequently decreased, and cluster 3 showed persistently elevated concentrations. The temporal biomarker patterns of patients in cluster 3 were similar to those with a repeat ACS during the first year. Clusters 1 and 2 had a similar and favorable long-term mortality risk. Cluster 3 had the highest mortality risk. The adjusted survival time ratio was 0.64 (95% CI, 0.44-0.93; P=0.018) compared with cluster 1, and 0.71 (95% CI, 0.39-1.32; P=0.281) compared with patients with a repeat ACS. CONCLUSIONS: Patients with subphenotypes of post-ACS with different all-cause mortality risks during long-term follow-up can be identified on the basis of repeatedly measured cardiovascular biomarkers. Patients with persistently elevated biomarkers have the worst outcomes, regardless of whether they experienced a repeat ACS in the first year.

Randomized clinical trial evaluating the effects of administering acidogenic boluses at dry-off on udder health, milk yield, and herd removal.

Acidogenic boluses can mitigate potential negative effects of high milk yield at dry-off on udder health. This randomized controlled trial aimed to investigate the effect of administering acidogenic boluses at dry-off on dry period intramammary infection (IMI) dynamics and on milk production parameters, somatic cell count linear score (LSCC), clinical mastitis (CM), and herd removal in the next lactation. A total of 901 cows from 3 dairy farms were randomly allocated to a control (CON, n = 458; no administration of acidogenic boluses at dry-off) or treatment group (TRT, n = 443; administration of 2 acidogenic boluses at dry-off). Quarter milk samples were collected at dry-off and after calving and submitted for bacteriological milk culture. The effects of treatment on the presence of quarter-level postpartum IMI, cure of existing IMI, and acquisition of new IMI, and on the prevalence of cow-level high LSCC (LSCC ≥4) in the first 30 days in milk (DIM) were analyzed using mixed effects logistic regression. Mixed linear regression was used to analyze cow-level milk production parameters (i.e., milk yield, fat corrected milk, fat and protein yield, and LSCC) in the first 90 DIM and until 300 DIM. For CM and herd removal, Cox proportional hazard regression models were used. In addition to treatment group, lactation group at dry-off, presence of high LSCC in the last test-day, average milk yield in the week before dry-off, presence of CM in the lactation of enrollment, and biologically relevant interactions were offered in all models. There was no evidence of a difference in IMI dynamics or in milk, fat corrected milk, protein or fat yields in the subsequent lactation between groups. The TRT group had a lower LSCC in the first 2 mo postpartum compared with the CON group (2.58 ± 0.3 vs. 2.92 ± 0.3 and 2.42 ± 0.3 vs. 2.81 ± 0.3, for first and second month postpartum). The prevalence of high LSCC in the first 30 DIM was 9.1% lower in the TRT compared with the CON group (16.3% vs. 25.5%; risk difference: -9.2; 95% confidence interval [CI]: -15.8, -2.5). Cows in the TRT group exhibited reduced hazards of CM in the subsequent lactation compared with cows in the CON group (hazard ratio: 0.75; 95% CI: 0.63, 0.89) as well as a reduced hazard of herd removal (hazard ratio: 0.82, 95% CI: 0.77, 0.88). The administration of acidogenic boluses as a component of dry-off management is a promising approach to maintain good udder health and reduce the hazard of CM and herd removal during the subsequent lactation.

A randomized clinical trial evaluating the effects of administration of acidogenic boluses at dry-off on rumination and activity behavior in the 14 subsequent days.

Elevated milk production at dry-off can lead to increased udder pressure and, in turn, increased stress due to pain and discomfort, affecting natural behaviors. Administering acidogenic boluses at dry-off acts by inducing temporary and mild decreases in blood pH. This decreases dry matter intake, reduces milk yield, and increases cow comfort by lessening udder pressure. The objective of this study was to assess the effect of oral administration of acidogenic boluses at dry-off on total daily activity (TDA) and total daily rumination (TDR) behaviors in the first 2 wk of the dry period. This randomized clinical trial was conducted on a single farm and cows were randomly assigned to either treatment (TRT; n = 30) or control (CON; n = 34). The TRT group received 2 acidogenic boluses at dry-off and the CON group received no intervention. All cows received dry-cow therapy (intramammary antibiotic and internal teat sealant). The TDA and TDR data from 7 d before to 14 d after dry-off were measured using ear-mounted activity monitors. Analyses were performed using linear mixed-effects models with repeated measures. We observed a similar TDA in both groups throughout the study follow-up period. Overall, cows in the TRT group spent 17 min/d less time active than cows in the CON group in the first 2 wk after dry-off with the greatest difference observed on the second day of the dry period (TRT = 395 min/d; 95% CI: 370 to 420 vs. CON = 428 min/d; 95% CI: 404 to 451). The TRT group had lower TDR in the first 24 h after bolus administration (TRT = 437 min/d; 95% CI: 414 to 461 vs. CON = 488 min/d; 95% CI: 466 to 510) when compared with the CON group, but no differences were observed when comparing both groups in the 13 subsequent days. Our results indicate that administering acidogenic boluses at dry-off slightly decreased TDA during the first 2 wk of the dry period and decreased TDR on the first day after administration.

An iterative approach to the development of a sole ulcer induction model in Holstein cows.

Our objective was to develop a sole ulcer (SU) induction model that can be used to investigate new and more efficacious methods for the treatment and prevention of SU. Three iterations [phase (P)1, P2, and P3] of an SU induction model designed to mimic mechanical and presumed metabolic pathways for SU development were conducted. The results from P1 and P2 identified alterations for the subsequent phase. Each phase used cows with similar calving dates that were randomly assigned (n = 4) to treatments. Control cows (P1CON, P3CON) did not undergo any challenges to induce SU development. Treatment cows were challenged with a hoof block (B) applied to the right hind lateral hoof. Other treatments included restricted lying time (L), restricted feed intake (F), or systemic lipopolysaccharide (LPS) administration. Treatment comparisons were P1CON versus P1BL, P2B versus P2BL, and P3CON versus P3BLF and P3BLF+LPS for P1, P2, and P3, respectively. Pregnant nulliparous Holstein cows were used in P1 and P3, and the P1 cohort was used in P2 during mid-lactation [125.9 ± 7.20 d in milk (DIM)]. Challenges were applied during a set challenge period (P1: -14 to 14 DIM, P2: 126-168 DIM, P3: -14 to 28 DIM). The P1BL cows had a hoof block applied and lying time restricted for 5 h/d. The P2B and P2BL cows had a hoof block and P2BL cows also had their lying time restricted for 18 h/d for 2 d/wk. The P3BLF and P3BLF+LPS cows had a hoof block, 6 h/d of lying time restricted 2 d/wk, and had their DMI restricted by 30% for 2 d/wk. At weekly intervals during wk 1 to 3 postpartum, P3BLF+LPS cows received jugular administration of 0.031, 0.062, and 0.125 µg of LPS per kg of body weight, respectively. Primary response measurements included hoof lesion and locomotion scoring, lying time, hoof thermography, and weight distribution per hoof. No SU induction occurred but sole hemorrhages, a precursor to SU, occurred during the postchallenge period of all phases. Temperature of the blocked hoof at the end of the challenge period did not change for P3CON cows but increased by 5.5°C and 6.2°C for P3BLF and P3BLF+LPS, respectively. Notable increases in lameness and lack of weight-bearing on the blocked hind hoof occurred for challenge treatment cows during the challenge period of P2 and P3. These changes did not persist after the hoof blocks were removed, indicating that hoof blocks succeeded in altering cow gait mechanics, but not enough to induce long-term lameness or SU. Lying restriction challenged cows in P2 and P3, indicated by a compensatory increase in lying time on the day following lying restriction compared with that on the day before restriction. In P3, lying time had the greatest depression during restriction and compensation following restriction in P3BLF+LPS cows, with LPS challenges potentially increasing the other challenge's effects. Future iterations of the SU induction model should include hoof block use, evaluate longer and more frequent standing and inclusion of forced walking bouts, and include DMI and LPS metabolic challenges.

Serially measured high-sensitivity cardiac troponin T, N-terminal-pro-B-type natriuretic peptide, high-sensitivity C-reactive protein, and growth differentiation factor 15 for risk assessment after acute coronary syndrome: the BIOMArCS cohort.

AIMS: Evidence regarding the role of serial measurements of biomarkers for risk assessment in post-acute coronary syndrome (ACS) patients is limited. The aim was to explore the prognostic value of four, serially measured biomarkers in a large, real-world cohort of post-ACS patients. METHODS AND RESULTS: BIOMArCS is a prospective, multi-centre, observational study in 844 post-ACS patients in whom 12 218 blood samples (median 17 per patient) were obtained during 1-year follow-up. The longitudinal patterns of high-sensitivity cardiac troponin T (hs-cTnT), N-terminal-pro-B-type natriuretic peptide (NT-proBNP), high-sensitivity C-reactive protein (hs-CRP), and growth differentiation factor 15 (GDF-15) were analysed in relation to the primary endpoint (PE) of cardiovascular mortality and recurrent ACS using multivariable joint models. Median age was 63 years, 78% were men and the PE was reached by 45 patients. The average biomarker levels were systematically higher in PE compared with PE-free patients. After adjustment for 6-month post-discharge Global Registry of Acute Coronary Events score, 1 standard deviation increase in log[hs-cTnT] was associated with a 61% increased risk of the PE [hazard ratio (HR) 1.61, 95% confidence interval (CI) 1.02-2.44, P = 0.045], while for log[GDF-15] this was 81% (HR 1.81, 95% CI 1.28-2.70, P = 0.001). These associations remained significant after multivariable adjustment, while NT-proBNP and hs-CRP were not. Furthermore, GDF-15 level showed an increasing trend prior to the PE (Structured Graphical Abstract). CONCLUSION: Longitudinally measured hs-cTnT and GDF-15 concentrations provide prognostic value in the risk assessment of clinically stabilized patients post-ACS. CLINICAL TRIAL REGISTRATION: The Netherlands Trial Register. Currently available at URL https://trialsearch.who.int/; Unique Identifiers: NTR1698 and NTR1106.

Association between engagement in exercise training and peak cardiac biomarker concentrations following ST-elevation myocardial infarction.

Background: Regular exercise training is an important factor in prevention of myocardial infarction (MI). However, little is known whether exercise engagement prior to MI is related to the magnitude of post-MI cardiac biomarker concentrations and clinical outcomes. Objectives: We tested the hypothesis that exercise engagement in the week prior MI is related to lower cardiac biomarker concentrations following ST-elevated MI (STEMI). Methods: We recruited hospitalised STEMI patients and assessed the amount of exercise engagement in the 7 days preceding MI onset using a validated questionnaire. Patients were classified as 'exercise' if they performed any vigorous exercise in the week prior MI, or as 'control' if they did not. Post-MI peak concentrations of high-sensitive cardiac troponin T (peak-hs-cTnT) and creatine kinase (peak-CK) were examined. We also explored whether exercise engagement prior MI is related to the clinical course (duration of hospitalisation and incidence of in-hospital, 30-day and 6-month major adverse cardiac events (reinfarction, target vessel revascularisation, cardiogenic shock or death)). Results: In total, 98 STEMI patients were included, of which 16% (n=16) was classified as 'exercise', and 84% (n=82) as 'control'. Post-MI peak-hs-cTnT and peak-CK concentrations were lower in the exercise group (941 (645-2925) ng/mL; 477 (346-1402) U/L, respectively) compared with controls (3136 (1553-4969) ng/mL, p=0.010; 1055 (596-2019) U/L, p=0.016, respectively). During follow-up, no significant differences were found between both groups. Conclusion: Engagement in exercise is associated with lower cardiac biomarker peak concentrations following STEMI. These data could provide further support for the cardiovascular health benefits of exercise training.

Exploring the role of milk yield in the first week of lactation on the association between hyperketonemia and reproductive performance in dairy cattle.

The objective of this retrospective cohort study was to investigate whether the association of hyperketonemia (HYK) with reproductive performance differs based on milk production during the first week of lactation (wk 1). Data between calving and 150 d in milk (DIM) from 2,091 Holstein dairy cows from 5 commercial dairy herds in Minnesota were collected. The concentration of ß-hydroxybutyrate (BHB) was measured twice between 3 and 10 DIM in whole blood to diagnose HYK (defined as BHB ≥1.2 mmol/L). The average wk 1 milk yield was classified into 3 levels (low = lower 25th percentile; mid = 25th to 75th percentile; high = upper 75th percentile) according to parity and herd. Log-binomial regression, Cox-proportional hazard regression, and linear regression models were used to investigate the association of HYK with pregnancy to first insemination, pregnancy by 150 DIM, and calving-to-conception interval (CCI) between groups, respectively. To describe the differences in these estimates between each wk 1 milk yield level, an interaction term of HYK and stratified levels of wk 1 milk yield was added. The incidence of HYK between 3 to 10 DIM was 14.2% (4.6% in primiparous cows and 19.4% in multiparous cows). In the study population, the effect of HYK on reproduction was greater in cows with low milk yield. Among cows with low milk yield levels, HYK was associated with lower risk of pregnancy to first insemination [risk ratio = 0.62; 95% confidence interval (CI): 0.39-0.98], lower risk of pregnancy up to 150 DIM (hazard ratio = 0.70; 95% CI: 0.51-0.96), and extended days of CCI (mean difference = 13.0; 95% CI: 5.1-20.9). In contrast, among cows with mid and high wk 1 milk yield levels, hyperketonemic (HYK+) cows had a similar reproductive performance to non-HYK (HYK-) cows. Our results suggest that early-lactation milk yield plays a role in the association of hyperketonemia with reproductive performance. These results merit further investigation to determine the role that early milk yield has in the association of hyperketonemia with health and productivity outcomes.

Promoting farm advisor engagement and action toward the improvement of dairy cattle lameness.

Lameness represents a significant management challenge in the dairy industry worldwide. In addition to farmers, many advisors are involved in lameness management, including veterinarians, hoof trimmers, and nutritionists. These advisors support farmers through lameness prevention practices, treatments, and advice, but little is known about how advisors view others' roles and the extent to which they work together. This study used qualitative participatory methods to facilitate the formation of lameness advisory groups among 13 advisors (4 veterinarians, 5 hoof trimmers, and 4 nutritionists), with the aims of promoting advisors' engagement with one another and documenting their perceptions of the benefits and challenges of the research activities through semi-structured interviews and thematic analysis. Participants shared predominantly positive views toward the project and voiced appreciation about the quality of discussions and the opportunity to connect and build relationships with other advisors. Participants reported improved communication with others via sharing reports and farm information, as well as increased confidence in reaching out to other advisors. Reported challenges included time constraints and discomfort in leading the lameness advisory group meetings. Difficulties were also found in bringing issues to farmers' attention when they might not align with the farmers' goals or priorities, as well as participants' questioning other advisors' knowledge and intentions. This study describes a promising avenue of facilitating advisor engagement, although more work is needed to determine whether such engagement translates to a reduction of lameness on farms.

Using a target trial approach to evaluate the role of hyperketonemia in sole ulcer and white line hoof lesion development.

This observational cohort study enrolled cows from 7 freestall dairy herds in Minnesota and Wisconsin. The objective was to estimate the causal role of hyperketonemia on new sole ulcer and white line hoof lesions (SUWL). Multiparous cows were enrolled at the time of their precalving hoof trim, at the end of their previous lactation. Enrolled cows were hoof trimmed twice: precalving between 90 to 21 d before calving (n = 2,037), and postcalving between 21 to 150 d after calving (n = 1,408). We trained 7 commercial hoof trimmers, employed by the farms, in lesion identification to standardize lesion recording. Hoof trimmers conducted therapeutic trimming as well as diagnosing and treating lesions. After parturition, cows between 3 and 16 d in milk were tested once weekly for hyperketonemia using a hand-held ketone meter. Farm staff and research personnel conducted the ß-hydroxybutyrate (BHB) testing. Cows were classified as hyperketonemic (HYK+) if they had a blood BHB ≥1.2 mmol/L or hyperketonemia-negative (HYK-) if blood BHB <1.2 mmol/L. At the precalving hoof trim, 15.6% of cows trimmed had a lesion and 1.9% of cows had a SUWL; thus, cows with a SUWL were excluded from further analysis (n = 38). At the postcalving hoof trim, 25.8% of cows trimmed had a hoof lesion, and 3.6% of cows had a SUWL. The most prevalent lesions at the pre- and postcalving hoof trims were digital dermatitis and corkscrew lesions. The incidence of hyperketonemia among cows was 21.1% (421/1,999) and the incidence on farms ranged from 5.7 to 29.1%. After excluding cows due to being hoof trimmed outside our designated window, the multilevel logistic regression model for the odds of SUWL at the postcalving hoof trim included 1,209 cows (HYK+ = 257/1,209; SUWL = 42/1,209). The odds of having SUWL in HYK+ was 0.66 (95% confidence interval: 0.29, 1.49) times the odds of that for HYK- cows. For cows diagnosed with a lesion (digital dermatitis, corkscrew, toe, foot rot, or other lesion) at their precalving hoof trim (n = 199), the odds of having SUWL for HYK+ cows were 0.43 (95% confidence interval: 0.05, 3.92) times the odds of that for HYK- cows. The wide range of compatible causal estimates suggest that hyperketonemia likely has a limited role in the development of SUWL in cows with or without a hoof lesion precalving. Future research should investigate other transition period factors such as inflammation or structural changes to the foot that may have a causative role in the development of SUWL.

Assessment of milk yield and composition, early reproductive performance, and herd removal in multiparous dairy cattle based on the week of diagnosis of hyperketonemia in early lactation.

The purpose of this retrospective cohort study was to evaluate the effects of the timing of hyperketonemia (HYK) diagnosis during early lactation on milk yield and composition, reproductive performance, and herd removal. Plasma ß-hydroxybutyrate (BHB) was measured twice a week during the first 2 wk of lactation in 362 multiparous Holstein cows for the diagnosis of HYK. In each week, cows were diagnosed as HYK positive (HYK+) if the plasma BHB concentrations were ≥1.2 mmol/L in at least one of the tests for the week evaluated. Milk-related outcomes (first 10 monthly milk tests) included milk yield, milk fat and protein content, milk urea nitrogen (MUN), and linear score of somatic cell count. Other performance outcomes of interest included risk of pregnancy within 150 d in milk (DIM) and herd removal (i.e., culling or death) within 300 DIM. Statistical models were built separately for cows diagnosed with HYK during the first week of lactation (wk1) and for cows diagnosed during the second week of lactation (wk2). All models for wk2 were adjusted by HYK diagnosed in wk1, along with other potential confounder variables. The association between HYK in each week and milk-related outcomes was assessed using generalized estimated equation models that accounted for repeated measures. Time to pregnancy and time to herd removal were analyzed using Cox's proportional hazard regression models. Seventy-eight cows (21.5%) tested positive for HYK during wk1, 60 cows (16.6%) in wk2, and 29 cows (8.0%) in both weeks. Hyperketonemia during wk1 was associated with a milk yield reduction of 3.7 kg [95% confidence interval (CI): -6.67 to -0.76] per cow per day throughout the lactation. Meanwhile, we did not observe evidence of an association between HYK diagnosed during wk2 and milk yield. During the first 2 monthly milk tests, cows diagnosed as HYK+ in wk1 had greater fat (0.42%; 95% CI: 0.16 to 0.67) and MUN (0.75 mg/dL; 95% CI: 0.26 to 1.24) content in milk than HYK-negative (HYK-) cows. We did not detect any evidence of an association between HYK diagnosed in wk2 and these outcomes. The HYK+ cows in wk1 had a 30% [hazard ratio (HR) = 0.70; 95% CI: 0.48 to 1.01] lower risk of pregnancy within 150 DIM and 2.48 times (95% CI: 1.63 to 2.89) higher risk of herd removal within 300 DIM than HYK- cows. Conversely, no evidence of association was observed between HYK+ cows in wk2 and risk of pregnancy by 150 DIM (HR = 0.98; 95% CI: 0.64 to 1.51) or removal from the herd within 300 DIM (HR = 0.91; 95% CI: 0.52 to 1.60). Our findings indicate that HYK diagnosed during wk1 of lactation is associated with negative performance in terms of milk yield, reproduction, and herd removal. No evidence of association was found for the same outcomes when HYK was diagnosed in wk2. Our results suggest the need to consider the timing when HYK is diagnosed when investigating its association with performance outcomes.

Dairy farmer, hoof trimmer, and veterinarian perceptions of barriers and roles in lameness management.

Lameness is a leading animal welfare concern in the dairy industry. Multiple stakeholders are involved in lameness management on a dairy farm, including farmers, hoof trimmers, and veterinarians. This study sought to explore perceptions of lameness, perceptions of roles in lameness management, and barriers to improved lameness management in these groups. Fourteen homogeneous focus groups were held in Minnesota, Wisconsin, and New York from April 2017 to March 2020; 5 with farmers (n = 31), 4 with hoof trimmers (n = 32), and 5 with veterinarians (n = 25). The 1-h facilitated discussions were audio-recorded, transcribed verbatim, and common themes identified through thematic analysis. Lameness was perceived by participants as a complex health problem and one in which the connections between pathogenesis, facilities, and management were not always well understood or easy to change. The complexity of the problem encompassed the lack of agreement on a definition of lameness, normalization to its signs, and the interconnectedness of lameness with other health and management issues. These issues appeared to contribute to resignation by participants that lameness was inevitable. Despite shared concerns about lameness among these groups, respondents reported a lack of communication, especially between hoof trimmers and veterinarians. Participants also voiced a desire to work together more productively, with hoof trimmers and veterinarians valuing the ability to deliver a consistent message to farmers. These findings suggest a need for increased efforts to facilitate collaboration between farmers, hoof trimmers, and veterinarians to improve lameness management on dairy farms.

Usefulness of High-Sensitivity Cardiac Troponin T to Predict Long-Term Outcome in Patients with Hypertrophic Cardiomyopathy.

Since the first report of an association between cardiac troponin (cTn) and adverse outcome in hypertrophic cardiomyopathy (HD), there is a paucity in confirmative data. We performed a prospective, prespecified 5-year follow-up cohort study of 135 HC patients who participated in a national multicenter project and underwent clinical evaluation, MRI (cine, LGE and T2-weighted imaging) and biomarker assessment (high-sensitivity cTnT (hs-cTnT), N-terminal pro-B-type natriuretic peptide, soluble tumorgenicity suppressor-2, Galectin-3, Growth differentiation factor-15, C-terminal Propeptide of Type I Collagen (CICP)). An elevated hs-cTnT concentration was defined as ≥14ng/L. Follow-up was systematically performed for the primary endpoint: a composite of sudden cardiac death, heart failure related death, stroke-related death, heart failure hospitalization, hospitalization for stroke, spontaneous sustained ventricular tachycardia (VT) or appropriate ICD discharge, and progression to NYHA class III-IV. Elevated hs-cTnT was present in 33 of 135 (24%) HC patients. During a median follow-up of 5.0 years (IQR: 4.9-5.1) 18 patients reached the primary endpoint. Using Cox regression analysis, elevated hs-cTnT was univariately associated with the primary endpoint (HR: 3.4 (95%CI: 1.4-8.7, p=0.009). Also female sex, previous syncope, previous non-sustained VT, reduced LV ejection fraction (<50%) and CICP were associated with the primary endpoint. In multivariable analysis, elevated hs-cTnT remained independently associated with outcome (aHR: 4.7 (95%CI: 1.8-12.6, p = 0.002). In conclusion, this 5-year follow-up study is the first to prospectively confirm the association of elevated hs-cTnT and adverse outcomes. In addition to established clinical variables, cTn seems the biomarker of interest to further improve risk prediction in HC, which should be evaluated in larger prospective registries.

Diagnostic accuracy of a bovine specific electronic beta-hydroxybutyrate handheld meter in fresh blood and stored serum samples.

This study aims to evaluate the diagnostic accuracy of the bovine specific beta-hydroxybutyrate (BHB) meter Nova Vet (NVET). We evaluated the accuracy and agreement of the NVET in fresh blood and thawed serum with the reference laboratory assay; and the repeatability, the interference by anticoagulants, and the optimum slope calibration factor. Individual blood samples were collected from 200 Holstein and crossbred cows between 3 and 14 days post-calving from 13 dairy herds in Minnesota. Using a laboratory assay with a cut point of 1.2 BHB mmol/L hyperketonemia prevalence was 10.6% (95% CI: 6.7, 15.8). The sensitivity of NVET in blood and serum was 100.0% while the specificity was 98.3 and 97.7% respectively. The agreement between NVET and the laboratory assay was the highest using blood samples (concordance correlation coefficient -CCC = 96.2, 95% CI: 95.0, 97.1. The coefficient of variation including within day (intra-meter), between- days, and -batches was 13.4% when testing blood samples. Minimal interference was observed with the use of anticoagulants (K-EDTA and Li-Heparin, CCC 0.90 and 0.93 respectively) in reference to whole blood without anticoagulant. The best calibration slope factor in serum was 1.0 (Youden's index: 0.98). Results suggest that the NVET device maintained a high accuracy and precision to quantified BHB concentration when applied in fresh blood and thawed serum under field conditions using the default calibration slope (1.0), and with minimal anticoagulant interference when used in whole blood samples.

Evaluating the association between early-lactation lying behavior and hoof lesion development in lactating Jersey cows.

Objectives were to evaluate the association between behavior and hoof lesions (HL) in lactating dairy cows. Jersey cows without any visible HL on all 4 legs were enrolled at 20 ± 3 d in milk (DIM), examined for body condition score (BCS), and had an automatic activity monitor (AfiTag II, AfiMilk, Afikim, Israel) attached to their right hind leg. At 120 ± 3 DIM, activity monitors were removed and cows were re-examined for HL and BCS. Cows were classified according to HL status as either healthy or with HL at d 120. Because sole hemorrhage (SH) accounted for over 80% of HL on d 120, SH was reclassified according to the number of feet affected. Daily activity data (daily lying duration, lying bouts, lying bout duration, and number of steps) of 344 cows collected between d 20 and d 120 were analyzed using restricted maximum likelihood linear mixed models with an autoregressive covariance structure. Separate models were built to include specific activities, HL status at d 120, DIM, interaction between lesion status at d 120 and DIM, parity, season of calving, and BCS change from d 20 to d 120 as fixed effects. Cow was included in all models as random effect. Incidence of HL at d 120 was 58.4% (n = 201 out of 344). Compared with healthy cows, cows with HL at d 120 had reduced daily lying duration (-0.53 h; 95% CI: -0.78 to -0.28 h) in the early postpartum period. We found no evidence for a difference in number of lying bouts (0.41; 95% CI: -0.76 to 1.59;), lying bout duration (-3.04 min; 95% CI: -6.6 to 0.49), and number of steps (62.14; 95% CI: -89.62 to 213.91) between cows that remained healthy and those that developed HL. Compared with healthy cows, cows that developed SH in 1 or more feet had reduced daily lying duration in the early postpartum period. Irrespective of lesion status at d 120, daily lying duration and lying bout duration increased from d 20 to d 120, whereas lying bout number and number of steps decreased from d 20 to d 120. We concluded that cows that developed HL had a reduced daily lying duration in the early postpartum period. Therefore, reduced daily lying duration should be considered a risk factor for HL development in lactating dairy cows.

Association between hoof lesions and fertility in lactating Jersey cows.

The objectives of this study were to evaluate the association between hoof lesions and fertility in dairy cows. Lactating Jersey cows (n = 1,639) were enrolled at 20 ± 3 d in milk (D20), examined and treated for presence of hoof lesions (HL), and evaluated for body condition score (BCS). Afterward, they were managed according to standard farm procedures, including estrus detection and presynchronization and a 5 d Cosynch-72 protocol for cows that failed to show estrus. Ovaries were scanned at 27 and 41 ± 3 d in milk, and cows with a corpus luteum greater than 20 mm on at least 1 exam were considered cyclic. At 120 ± 3 d in milk (D120), cows were re-examined for HL and BCS. Cows were classified at D20 according to HL status as healthy (n = 1,197) or having HL (n = 429), and according to HL category as healthy (n = 1,197) or having a sole hemorrhage (n = 280), noninfectious HL (sole ulcer, toe ulcer, or white line disease; n = 113), or infectious HL (digital dermatitis and foot rot; n = 36). Cows with HL at D20 had reduced odds of being cyclic (38.3 vs. 51.9%) and a longer interval from calving to first service (58 vs. 51 d) compared with healthy cows. Cows with infectious HL at D20 had reduced odds of pregnancy to first service (16.7 vs. 38.3%) compared with healthy cows. Cows with sole hemorrhage at D20 were more likely to lose pregnancies between d 32 and 64 after the first service postpartum compared with healthy cows (10.5 vs. 5.2%). Cows with sole hemorrhage at D20 had a smaller hazard of pregnancy (67.9 vs. 75.5%) at 150 d in milk and more days open (88 vs. 77d) compared with healthy cows. To assess the relationship between the development of HL and fertility, cows were classified as healthy (no HL at D20 and D120; n = 308), cured (any HL at D20 and no HL at D120; n = 72), new HL (no HL at D20 and any HL at D120; n = 597), and chronic (any HL at D20 and D120; n = 226). Sole hemorrhage accounted for 93% of new HL. The proportions of cows with HL at D20 and D120 were 26.9 and 68.4%, respectively. We found no evidence for a difference in pregnancy hazard at 150 d in milk between cows that remained healthy (n = 308) and cows that developed new HL (n = 597). Hoof lesions at D20, but not new HL, were associated with decreased odds of cyclicity, longer interval from calving to first service postpartum, and reduced pregnancy hazard in Jersey cows. The effect of an HL diagnosis in early lactation and management to reduce chronic HL in dairy cows warrants further investigation.

Exercise and myocardial injury in hypertrophic cardiomyopathy.

OBJECTIVE: Troponin and high signal intensity on T2-weighted (HighT2) cardiovascular magnetic resonance imaging (CMRi) are both markers of myocardial injury in hypertrophic cardiomyopathy (HCM). The interplay between exercise and disease development remains uncertain in HCM. We sought to assess the occurrence of postexercise troponin rises and its determinants. METHODS: Multicentre project on patients with HCM and mutation carriers without hypertrophy (controls). Participants performed a symptom limited bicycle test with hs-cTnT assessment pre-exercise and 6 hours postexercise. Pre-exercise CMRi was performed in patients with HCM to assess measures of hypertrophy and myocardial injury. Depending on baseline troponin (< or >13 ng/L), a rise was defined as a >50% or >20% increase, respectively. RESULTS: Troponin rises occurred in 18% (23/127) of patients with HCM and 4% (2/53) in mutation carriers (p=0.01). Comparing patients with HCM with and without a postexercise troponin rise, maximum heart rates (157±19 vs 143±23, p=0.004) and maximal wall thickness (20 mm vs 17 mm, p=0.023) were higher in the former, as was the presence of late gadolinium enhancement (85% vs 57%, p=0.02). HighT2 was seen in 65% (13/20) and 19% (15/79), respectively (p<0.001). HighT2 was the only independent predictor of troponin rise (adjusted odds ratio 7.9; 95% CI 2.7 to 23.3; p<0.001). CONCLUSIONS: Postexercise troponin rises were seen in about 20% of patients with HCM, almost five times more frequent than in mutation carriers. HighT2 on CMRi may identify a group of particularly vulnerable patients, supporting the concept that HighT2 reflects an active disease state, prone to additional injury after a short episode of high oxygen demand.

Multi-Site Coronary Vein Sampling Study on Cardiac Troponin T Degradation in Non-ST-Segment-Elevation Myocardial Infarction: Toward a More Specific Cardiac Troponin T Assay.

Background Cardiac troponin T ( cTnT ) is seen in many other conditions besides myocardial infarction, and recent studies demonstrated distinct forms of cTnT . At present, the in vivo formation of these different cTnT forms is incompletely understood. We therefore performed a study on the composition of cTnT during the course of myocardial infarction, including coronary venous system sampling, close to its site of release. Methods and Results Baseline samples were obtained from multiple coronary venous system locations, and a peripheral artery and vein in 71 non- ST -segment-elevation myocardial infarction patients. Additionally, peripheral blood was drawn at 6- and 12-hours postcatheterization. cTnT concentrations were measured using the high-sensitivity- cTnT immunoassay. The cTnT composition was determined via gel filtration chromatography and Western blotting in an early and late presenting patient. High-sensitivity - cTnT concentrations were 28% higher in the coronary venous system than peripherally (n=71, P<0.001). Coronary venous system samples demonstrated cT n T-I-C complex, free intact cTnT , and 29 kD a and 15 to 18 kD a cTnT fragments, all in higher concentrations than in simultaneously obtained peripheral samples. While cT n T-I-C complex proportionally decreased, and disappeared over time, 15 to 18 kD a cTnT fragments increased. Moreover, cT n T-I-C complex was more prominent in the early than in the late presenting patient. Conclusions This explorative study in non- ST -segment-elevation myocardial infarction shows that cTnT is released from cardiomyocytes as a combination of cT n T-I-C complex, free intact cTnT , and multiple cTnT fragments indicating intracellular cTnT degradation. Over time, the cT n T-I-C complex disappeared because of in vivo degradation. These insights might serve as a stepping stone toward a high-sensitivity- cTnT immunoassay more specific for myocardial infarction.

Cardiac troponin I is present in plasma of type 1 myocardial infarction patients and patients with troponin I elevations due to other etiologies as complex with little free I.

BACKGROUND: Cardiac troponin (cTn) is a complex of three subunits (T, I, and C), with some studies reporting that ~5-10% is cytosolic and unbound ('free'). It has been hypothesized that free cTn is released before complex and before or without cell death dependent on the severity of ischemia. In this context, new generation assays that can discriminate free, binary (IC) and ternary (TIC) complex forms may aid to differentiate between type 1 myocardial infarction (MI) and cTn elevations due to different etiologies, e.g. demand ischemia and type 2 MI. METHODS: Serial plasma samples from six type 1 MI patients and twenty-seven patients with other cTnI elevations, e.g. due to demand ischemia and type 2 MI, were analyzed using high-sensitivity ET Healthcare Pylon assays for total cTnI, complex cTnI (IC and TIC), and cTnTIC. The specificity of the anti-cTnT antibody in the cTnTIC assay was such that only full-size cTnTIC is detected. In vitro stability of different cTnI forms was assessed by spiking free cTnI and cTnTIC in cTnI-free serum, incubating at 4 or 37 °C, and measuring different cTnI forms over 0-182 h. Presence of cytosolic free cTnI was evaluated on fixed rat cardiac tissue using an antibody against free cTnI. RESULTS: Pylon assays for total and complex cTnI tracked well over time with each other and gave similar results, both for type 1 MI and non-type 1 MI patients, indicating that the vast majority was complex cTnI. As a minority of complex cTnI was full-size cTnTIC, this indicated that complex cTnI mainly consisted of a degraded form of cTnTIC (low-molecular weight cTnTIC) and/or cTnIC. Full-size cTnTIC was more abundant in early compared to late samples. In vitro studies indicated that free cTnI and cTnTIC are not stable at 37 °C (28% and 11% recovery after 24 h, respectively) and this is also true to some extent for cTnTIC at 4 °C (60% recovery after 24 h). Free cTnI was not readily detected in rat cardiac tissue. CONCLUSIONS: In agreement with type 1 MI, cTnI in samples of patients with cTnI elevations due to other etiologies is found predominantly as complex cTnI, of which some is full-size cTnTIC. In most cases, assays for total and complex cTnI indicated there was little free cTnI; however, its presence cannot be completely excluded, due to the inability of its direct measurement and limited stability.

Association between Lifelong Physical Activity and Disease Characteristics in HCM.

PURPOSE: Hypertrophic cardiomyopathy (HCM) is characterized by inappropriate left ventricular (LV) wall thickness. Adaptations to exercise can occasionally mimic certain HCM characteristics. However, it is unclear whether physical activity affects HCM genotype expression and disease characteristics. Consequently, we compared lifelong physical activity volumes between HCM gene carriers with and without HCM phenotype, and compared disease characteristics among tertiles of physical activity in phenotypic HCM patients. METHODS: We enrolled n = 22 genotype positive/phenotype negative (G+/P-) HCM gene carriers, n = 44 genotype positive/phenotype positive (G+/P+) HCM patients, and n = 36 genotype negative/phenotype positive (G-/P+) HCM patients. Lifelong physical activity was recorded using a questionnaire and quantified as metabolic equivalent of task hours per week. RESULTS: We included 102 participants (51 ± 16 yr, 49% male). Lifelong physical activity volumes were not different between G+/P+ and G+/P- subjects (16 [10-29] vs 14 [6-26] metabolic equivalent of task-hours per week, P = 0.33). Among phenotypic HCM patients, there was no difference in LV wall thickness, mass, and late gadolinium enhancement across physical activity tertiles. Patients with the highest reported physical activity volumes were younger at the time of diagnosis (tertile 1: 52 ± 14 yr, tertile 2: 49 ± 15 yr, tertile 3: 41 ± 18 yr; P = 0.03), and more often had a history of nonsustained ventricular tachycardia (4% vs 30% vs 30%, P = 0.03). CONCLUSIONS: Lifelong physical activity volumes are not associated with genotype-to-phenotype transition in HCM gene carriers. We also found no difference in LV wall thickness across physical activity tertiles. However, the most active HCM patients were younger at the time of diagnosis and had a higher arrhythmic burden. These observations warrant further exploration of the role of exercise in HCM disease development.

5-aminolevulinic acid photodynamic therapy for the treatment of high-grade gliomas.

INTRODUCTION: Photodynamic therapy (PDT) is a two-step treatment involving the administration of a photosensitive agent followed by its activation at a specific light wavelength for targeting of tumor cells. MATERIALS/METHODS: A comprehensive review of the literature was performed to analyze the indications for PDT, mechanisms of action, use of different photosensitizers, the immunomodulatory effects of PDT, and both preclinical and clinical studies for use in high-grade gliomas (HGGs). RESULTS: PDT has been approved by the United States Food and Drug Administration (FDA) for the treatment of premalignant and malignant diseases, such as actinic keratoses, Barrett's esophagus, esophageal cancers, and endobronchial non-small cell lung cancers, as well as for the treatment of choroidal neovascularization. In neuro-oncology, clinical trials are currently underway to demonstrate PDT efficacy against a number of malignancies that include HGGs and other brain tumors. Both photosensitizers and photosensitizing precursors have been used for PDT. 5-aminolevulinic acid (5-ALA), an intermediate in the heme synthesis pathway, is a photosensitizing precursor with FDA approval for PDT of actinic keratosis and as an intraoperative imaging agent for fluorescence-guided visualization of malignant tissue during glioma surgery. New trials are underway to utilize 5-ALA as a therapeutic agent for PDT of the intraoperative resection cavity and interstitial PDT for inoperable HGGs. CONCLUSION: PDT remains a promising therapeutic approach that requires further study in HGGs. Use of 5-ALA PDT permits selective tumor targeting due to the intracellular metabolism of 5-ALA. The immunomodulatory effects of PDT further strengthen its use for treatment of HGGs and requires a better understanding. The combination of PDT with adjuvant therapies for HGGs will need to be studied in randomized, controlled studies.