Cardiac troponin I and T as prognostic markers in cats with hypertrophic cardiomyopathy

BACKGROUND

Myocardial injury detected by cardiac troponin I and T (cTnI and cTnT) in cardiac disease is associated with increased risk of death in humans and dogs.

HYPOTHESIS

Presence of myocardial injury predicts long-term death in cats with hypertrophic cardiomyopathy (HCM), and ongoing myocardial injury reflects change in left ventricular wall thickness over time.

ANIMALS

Thirty-six cats with primary HCM.

METHODS

Prospective cohort study. Cats with HCM were included consecutively and examined every 6 months. Echocardiography, ECG, blood pressure, and serum cTnI and cTnT were evaluated at each visit. Cox proportional hazards regression analysis was performed to evaluate prognostic potential of serum troponin concentrations at admission and subsequent examinations. Correlations were used to examine associations between troponin concentrations and cardiac hypertrophy.

RESULTS

Troponin concentrations at admission were median [range] 0.14 [0.004-1.02] ng/mL for cTnI, and 13 [13-79.5] ng/L for cTnT. Both were prognostic for death (P = .032 and .026) as were the last available concentrations of each (P = .016 and .003). The final cTnT concentration was a significant predictor of death even when adjusting for the admission concentration (P = .043). In a model containing both markers, only cTnT remained significant (P = .043). Left ventricular free wall thickness at end-diastole (LVFWd) at admission was correlated with cTnI at admission (r = 0.35, P = .035), however no significant correlations (r = 0.2-0.31, P = .074-.26) were found between changes in troponin concentrations and left ventricular thickness over time.

CONCLUSIONS AND CLINICAL IMPORTANCE

Myocardial injury is part of the pathophysiology leading to disease progression and death. Low sensitivities and specificities prevent outcome prediction in individual cats.

Reduction of misclassification rates of obesity by body mass index using dual-energy X-ray absorptiometry scans to improve subsequent prediction of per cent fat mass in a Caucasian population

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

•  Body mass index (BMI) is not accurate in the classification of excess body fat, failing to identify as many as half of individuals with excess per cent fat mass. •  Normal-weight obesity, which goes undiagnosed when BMI is the only measure of adiposity utilized, has been shown to be associated with an increased risk of cardiovascular comorbidities and mortality. •  Dual-energy X-ray absorptiometry (DXA) is an accurate and relatively inexpensive method for indirect assessment of body composition.

WHAT THIS STUDY ADDS

•  The formulae developed allow the clinician to utilize information from one baseline DXA scan to calculate a patient's per cent fat mass with a future change in weight, thus allowing the clinician to more accurately determine whether and when an individual patient should be classified as obese and thus be managed appropriately. •  The formulae developed enable the clinician to calculate a patient-specific BMI treatment goal, below which the patient would no longer meet the per cent fat mass criteria for obesity.

SUMMARY

Recognition is increasing for the errors of body mass index (BMI) in classification of excess body fat. Dual-energy X-ray absorptiometry (DXA) is accurate to assess body fat mass per cent (%FM), but is underutilized clinically. We examined the prevalence of obesity misclassification by BMI in comparison to body %FM by DXA scanning, and whether there is a time-stable individual relation between the %FM and the BMI in patients scanned several times. We aimed to develop a formula where, based on a single DXA scan, %FM could be predicted following a change in weight, and a patient-specific BMI threshold could be calculated (BMIT ), above which the patient would be obese by %FM criteria. Data were collected from individuals who had a DXA scan as part of a nutritional research study at the University of Copenhagen. BMI incorrectly classified 48/329 (14.6%) of men and 52/589 (8.8%) of women. The majority of men with BMI 25-27 kg m(-2) and women with BMI 24-26 kg m(-2) were misclassified. Using multiple scan data (189 men, 311 women) and calculating the patient-specific constant C = (1 - %FM/100)(3/2)  × BMI from baseline BMI and %FM, misclassification rates were halved for both genders when a personal threshold, BMIT , was used ([BMIT  = C/(0.75)(3/2) ] for men and [BMIT  = C/(0.65)(3/2) ] for women). We conclude that simple formulae allow evaluation of fatness of individual patients more accurately than BMI, with the use of one baseline DXA scan, and enable the establishment of patient-specific obesity treatment targets in clinical practice.

Genetic analysis of resistance to yellow rust in hexaploid wheat using a mixture model for multiple crosses

DNA-based molecular markers have been used in numerous studies for tagging specific genes in wheat for subsequent use in marker-assisted selection. Usually in plant breeding, procedures for mapping genes are based on analysis of a single segregating population. However, breeding programmes routinely evaluate large numbers of progeny derived from multiple-related crosses with some parental lines shared. In most such related crosses, the number of progeny is quite small. Thus, statistical techniques for detecting quantitative trait loci (QTLs) using data from conventional multi-cross breeding programmes are interesting. The objective of this study is to present a mixture model for QTL mapping in crosses of multiple inbred varieties with non-normal phenotype distributions and to use this model to map QTLs for yellow rust resistance in elite wheat breeding material. Three doubled haploid populations consisting of 41, 42 and 55 lines, respectively, originating from four parental varieties were studied. Multi-cross QTL analysis with three specific pathogen isolates of Puccinia striiformis f. sp. tritici and a mixture of the isolates revealed QTLs for resistance at four different genomic locations. These QTLs were found on chromosome 2AL, 2AS, 2BL and 6BL and explained between 21 and 41% of the phenotypic variation. Two of these QTLs, one on the long arm of chromosome 2A and one on the short arm of chromosome 2A were identical to the known yellow rust resistance genes Yr32 and Yr17, respectively, whereas the QTLs located on the long arms of chromosomes 2B and 6B may reflect types of resistance to yellow rust, which have not previously been mapped.

The appetite-suppressant effect of nicotine is enhanced by caffeine

AIM

To test whether the anorectic effect of nicotine may be amplified by caffeine.

METHODS

Chewing gums with nicotine and caffeine were administered to 12 healthy young men of normal weight. Different combinations of 0, 1 or 2 mg of nicotine and 0, 50 or 100 mg of caffeine were applied during a 2-h period in a randomized, double blind, cross over design. Appetite sensations were measured using visual analogue scales.

RESULTS

Hunger and prospective food consumption were negatively associated with the increasing doses of nicotine, whereas satiety and fullness were positively associated with the increasing doses of nicotine (p < 0.05). Caffeine appeared to amplify the effects of nicotine on hunger and fullness as a caffeine x nicotine x time interaction was observed in these scores (p < 0.05). The 2-mg dose of nicotine in combination with the 100-mg dose of caffeine caused nausea in four of the non-smokers. However, the effects of nicotine and the caffeine x nicotine x time interaction persisted after the exclusion of these subjects.

CONCLUSION

Caffeine added to nicotine chewing gum appears to amplify its attenuating effects on appetite and the combinations of 1-mg of nicotine with caffeine seem to be well tolerated.

Analysis of potential duplicates in barley gene bank collections using re-sampling of microsatellite data

Redundant duplication among putative Nordic spring barley material held at 12 gene banks worldwide was studied using 35 microsatellite primer pairs covering the entire barley genome. These microsatellite markers revealed an average of 7.1 alleles per locus, and a range of 1 to 17 different alleles per locus. Similarity of accession name was initially used to partition the 174 repatriated accessions into 36 potential duplicate groups, and one group containing 36 apparently unique or unrelated accessions. This partitioning was efficient to produce a distribution of mainly small average genetic distances within potential duplicate groups compared to distances from the group of unique accessions. However, comparisons within potential duplicate groups still contained large genetic distances of the same size as distances between unique accessions indicating classification errors. A bootstrap approach based on re-sampling of both microsatellite markers and alleles within marker loci was used to test for homogeneity within potential duplicate groups. The test was used in each group for sequential elimination of accessions with a significantly large average genetic distance to identify a homogeneous group. Such genetically homogeneous groups of two or more accessions were identified in 22 among the 36 potential duplicate groups studied. Results from the genetic analysis of some potential duplicate groups supported previous conclusions based on passport data through inclusion of the historically most-original accession in the genetically homogeneous group. In other potential duplicate groups the apparently most-original accession according to passport data was not included in the homogeneous set of accessions, indicating that this most-original accession does not have duplicate accessions in the group. During the present study the largest average genetic distance accepted in any homogeneous group was smaller than the smallest distance declared significant in any group, with a threshold average genetic distance of approximately 0.14. The results are discussed with respect to the identification of duplicate accessions within potential duplicate groups, as well as the elimination of genetic off types in such groups. Furthermore, large barley gene bank collections may be screened for potential duplicates with genetic distances below the suggested threshold of 0.14.

From image processing to classification: III. Matching patterns by shifting and stretching

A method for the classification of electrophoretic patterns is described and tested on a data set representing ten wheat varieties. The method attempts to match each electropherogram to each variety by a transformation involving displacement and stretching along the x-axis. This is done essentially by the method of least squares, which uses only the information contained in the electropherogram itself to adjust it to the variety in question. The method is completely automatic and works extremely well by classifying 98% of the spectra correctly, judged by cross validation.

From image processing to classification: I. Modeling disturbances of isoelectric focusing patterns

In order to optimize the conditions for evaluation of isoelectric focusing (IEF) patterns by digital image processing, the sources of error in determination of the pI values were analyzed together with the influence of a varying background. The effects of band distortions, in the spectra of the individual lanes, were examined. In order to minimize the effect of these distortions, optimal conditions for handling IEF patterns by digital image processing were elucidated. The systematic part of the global deformation on the gels was investigated and an algorithm was developed by which it was possible to correct for a part of the individual distortions. The effects of various corrections for lane distortions were illustrated by classification, using different types of discriminant analysis. Finally the background disturbances were examined, and described by a mathematical model.

Antioxidant synergism between tocopherols and ascorbyl palmitate in cooked, minced turkey

In an attempt to reduce oxidative deterioration, including the development of warmed-over flavour (WOF), in cooked, minced turkey meat, a combined strategy using natural antioxidants and modified atmosphere packaging (MAP) was adapted. Tocopherols (200 ppm) each significantly reduced lipid oxidation during 9 days of cold storage (5 degrees C), measured as 2-thiobarbituric-acid-reactive substances (TBARS). Synergism between the two antioxidants was demonstrated as an increasing relative reduction in TBARS values over time when both antioxidants were added, as opposed to the almost constant relative reduction when only one antioxidant was added. Notably, this synergism depended on the availability of O2, and was found to be most significant for atmospheric packaging (21% O2, 79% N2) and most significant towards the end of the storage period. A reduced O2 content in the packages (mixture of O2 and N2, initially: 1.0% O2 or 0.03% O2) had a more pronouced effect on oxidative deterioration than addition of antioxidants. However, during the 9 days of storage, meat balls with the synergistic mixture added, and packed in 1% O2, had TBARS values of 50 compared to 270 mumol malondialdehyde/kg for meat balls without antioxidants packed in 21% O2. This level of reduction in lipid oxidation is comparable with that of meat balls without antioxidants packed in a virtually O2-free atmosphere.