Contrast-enhanced versus non-enhanced three-dimensional echocardiography of left ventricular volumes

Background In three-dimensional echocardiography (3DE), individual endocardial trabeculae are not clearly visible necessitating left ventricular (LV) volumes to be measured by tracing the innermost endocardial contour. Ultrasound contrast agents aim to improve endocardial definition, but may delineate the outermost endocardial contour by filling up intertrabecular space. Although measurement reproducibility may benefit, there may be a significant influence on absolute LV volume measurements. Methods Twenty patients with a recent myocardial infarction and good ultrasound image quality underwent 3DE using the TomTec Freehand method before and during continuous intravenous contrast infusion. LV volumes were measured offline using TomTec Echo-Scan software. Results The use of contrast enhancement increased end-diastolic (110±35 vs. 144±53 ml; p<0.01) and end-systolic volume measurements (68±31 vs. 87±45 ml; p<0.01) significantly compared with non-contrast; the ejection fraction remained unchanged (40±13 vs. 41±14%, p=NS). Measurement reproducibility did not improve significantly, however. Conclusion Volumes measured by 3DE are significantly larger when ultrasound contrast is used. Possibly, intertrabecular space comprises a substantial part of the LV cavity. In the presence of an adequate apical acoustic window, ultrasound contrast does not improve LV volume measurement reproducibility. (Neth Heart J 2008;16:47-52.)     

Application of infrared thermography as an indicator of heat and methane production and its use in the study of skin temperature in response to physiological events in dairy cattle (Bos taurus)

There is a demand in the livestock industry for alternative assessments of feed efficiency. Infrared thermography was tested for predicting heat production, methane production and for the detection of physiological events (e.g. heat increment of feeding) in dairy cattle. Multiple body locations were infrared scanned concomitantly with the measurement of the animals’ gaseous exchange. Infrared thermography can be successfully applied for assessing heat and methane production, through the analysis of feet temperature and temperature difference between left and right flanks, respectively. This technology is also useful for assessing physiological responses to milking and feeding.     

The Population Reference Sample, POPRES: a resource for population, disease, and pharmacological genetics research

Technological and scientific advances, stemming in large part from the Human Genome and HapMap projects, have made large-scale, genome-wide investigations feasible and cost effective. These advances have the potential to dramatically impact drug discovery and development by identifying genetic factors that contribute to variation in disease risk as well as drug pharmacokinetics, treatment efficacy, and adverse drug reactions. In spite of the technological advancements, successful application in biomedical research would be limited without access to suitable sample collections. To facilitate exploratory genetics research, we have assembled a DNA resource from a large number of subjects participating in multiple studies throughout the world. This growing resource was initially genotyped with a commercially available genome-wide 500,000 single-nucleotide polymorphism panel. This project includes nearly 6,000 subjects of African-American, East Asian, South Asian, Mexican, and European origin. Seven informative axes of variation identified via principal-component analysis (PCA) of these data confirm the overall integrity of the data and highlight important features of the genetic structure of diverse populations. The potential value of such extensively genotyped collections is illustrated by selection of genetically matched population controls in a genome-wide analysis of abacavir-associated hypersensitivity reaction. We find that matching based on country of origin, identity-by-state distance, and multidimensional PCA do similarly well to control the type I error rate. The genotype and demographic data from this reference sample are freely available through the NCBI database of Genotypes and Phenotypes (dbGaP).     

Erythrogenic toxins A, B and C: Occurrence of the genes and exotoxin formation from clinical Streptococcus pyogenes strains associated with streptococcal toxic shock-like syndrome

We report the study of 53 clinical isolates of group A streptococci, all from patients with streptococcal toxic shock-like syndrome. The strains were analysed for the occurrence of the genes of erythrogenic toxins (pyrogenic exotoxins) types A, B and C and in vitro production of these toxins. In contrast to reports indicating that 85% of the toxic shock-like syndrome-associated isolates contained the erythrogenic toxin A gene, only 58.5% of our strains harboured this gene. The erythrogenic toxin C gene was detected in 22.6% of the isolates. Erythrogenic toxin A and erythrogenic toxin B were produced by 68.7% and 58.3% of the strains containing either gene. For all group A streptococci, irrespective of clinical association, the erythrogenic toxin B gene was detected in all the isolates tested. Thus, it is difficult to define a specific role for erythrogenic toxin B in toxic shock-like syndrome as there was no clear correlation between this disease and the presence of toxin genes. Our results suggest the existence of other pathogenic factor(s) produced by group A streptococci which may stimulate human peripheral T lymphocytes in a manner similar to that of erythrogenic toxins, thus explaining different observations in previous epidemiological genetic studies.     

Loop‐mediated isothermal amplification (LAMP) for the identification of invasive Aedes mosquito species

Invasive Aedes mosquito species (Diptera: Culicidae) are of public health concern in Europe because they are either recognized or potential vectors of pathogens. Loop‐mediated isothermal amplification (LAMP) is a rapid and simple method for amplifying DNA with high specificity and efficiency, with the technique having potential for application in the field, including in high‐throughput format. Specific LAMP assays based on rDNA internal transcribed spacers 1 or 2 sequences, considering intraspecies variability at these loci, were developed for Aedes aegypti, Aedes albopictus, Aedes japonicus, Aedes koreicus and the indigenous Aedes geniculatus. No such assays could be developed for Aedes atropalpus and Aedes triseriatus because both loci were too short to serve as target. The assays rely on the clearly visible colour change from violet to sky blue after successful amplification. Sensitivity of egg detection was confirmed with ratios of up to one mosquito egg in 99 other eggs. Simple sample preparation of adults or eggs by mechanical homogenization in water required an additional heat treatment or centrifugation step to avoid non‐specific colour changes. Thus, further technical improvements are needed to render these assays truly field‐applicable, which would greatly facilitate surveillance of these invasive mosquito species and allow for prompt implementation of control measures.     

Graves' disease: immunological and immunogenetic indicators of relapse

The use of measurements of antibody to the thyroid stimulating hormone receptor and HLA-DR3 phenotype for predicting relapse of hyperthyroidism in patients with Graves'' disease receiving medical treatment is controversial. Fifty eight new patients with Graves'' disease were followed up prospectively for up to 96 months after treatment with antithyroid drugs for 12 months. The presence of antibody to the thyroid stimulating hormone receptor before the start of treatment, measured as immunoglobulins inhibiting binding of thyroid stimulating hormone, was not associated with relapse. Patients who remained positive for antibodies after treatment tended to relapse within six months, but no relation with long term relapse was found. HLA-Cw7 but not HLA-DR3 was significantly associated with relapse. The presence of HLA-DR4 was significantly associated with remission and with absence of antibodies to thyroid stimulating hormone receptor. HLA-DR4 may therefore protect against relapse of thyrotoxicosis by immunomodulation triggered by antithyroid drugs, which results in the synthesis of antibodies to the thyroid stimulating hormone receptor being inhibited.     

Zur Physiologie und Cytologie der Fettbildung bei Endomyces vernalis

Ohne ZusammenfassungD 93.—Als vorläufige Mitteilung erschien: M. Steiner, Ernährung und Fettbildung bei Endomyces vernalis. Ber. d. Deutsch. bot. Ges. 56, 73, 1938.