Echocardiographic detection of early diabetic myocardial disease

OBJECTIVES We sought to determine whether disturbances of myocardial contractility and reflectivity could be detected in diabetic patients without overt heart disease and whether these changes were independent and incremental to left ventricular hypertrophy (LVH). BACKGROUND Left ventricular (LV) dysfunction is associated with diabetes mellitus, but LVH is common in this population and the relationship between diabetic LV dysfunction and LVH is unclear. METHODS We studied 186 patients with normal ejection fraction and no evidence of CAD: 48 with diabetes mellitus only (DM group), 45 with LVH only (LVH group), 45 with both diabetes and LVH (DH group), and 48 normal controls. Peak strain and strain rate of six walls in apical four-chamber, long-axis, and two-chamber views were evaluated and averaged for each patient. Calibrated integrated backscatter (113) was assessed by comparison of the septal or posterior wall with pericardial IB intensity. RESULTS All patient groups (DM, DH, LVH) showed reduced systolic function compared with controls, evidenced by lower peak strain (p < 0.001) and strain rate (p = 0.005). Calibrated 113, signifying myocardial reflectivity, was greater in each patient group than in controls (p < 0.05). Peak strain and strain rate were significantly lower in the DH group than in those in the DM alone (p < 0.03) or LVH alone (p = 0.01) groups. CONCLUSIONS Diabetic patients without overt heart disease demonstrate evidence of systolic dysfunction and increased myocardial reflectivity. Although these changes are similar to those caused by LVH, they are independent and incremental to the effects of LVH. (C) 2003 by the American College of Cardiology Foundation.

Detection of differentially expressed genes in synovial fibroblasts by restriction fragment differential display

Objective. To identify differentially expressed genes in synovial fibroblasts and examine the effect on gene expression of exposure to TNF-alpha and IL-1beta. Methods. Restriction fragment differential display was used to isolate genes using degenerate primers complementary to the lysophosphatidic acid acyl transferase gene family. Differential gene expression was confirmed by reverse transcription-polymerase chain reaction and immunohistochemistry using a variety of synovial fibroblasts, including cells from patients with osteoarthritis and self-limiting parvovirus arthritis. Results. Irrespective of disease process, synovial fibroblasts constitutively produced higher levels of IL-6 and monocyte chemoattractant protein 1 (MCP-1) (CCL2) than skin fibroblasts. Seven genes were differentially expressed in synovial fibroblasts compared with skin fibroblasts. Of these genes, four [tissue factor pathway inhibitor 2 (TFPI2), growth regulatory oncogene beta (GRObeta), manganese superoxide dismutase (MnSOD) and granulocyte chemotactic protein 2 (GCP-2)] were all found to be constitutively overexpressed in synoviocytes derived from patients with osteoarthritis. These four genes were only weakly expressed in other synovial fibroblasts (rheumatoid and self-limiting parvovirus infection). However, expression in all types of fibroblasts was increased after stimulation with TNF-alpha and IL-1beta. Three other genes (aggrecan, biglycan and caldesmon) were expressed at higher levels in all types of synovial fibroblasts compared with skin fibroblasts even after stimulation with TNF-alpha and IL-1. Conclusions. Seven genes have been identified with differential expression patterns in terms of disease process (osteoarthritis vs rheumatoid arthritis), state of activation (resting vs cytokine activation) and anatomical location (synovium vs skin). Four of these genes, TFPI2, GRObeta (CXCL2), MnSOD and GCP-2 (CXCL6), were selectively overexpressed in osteoarthritis fibroblasts rather than rheumatoid fibroblasts. While these differences may represent differential behaviour of synovial fibroblasts in in vitro culture, these observations suggest that TFPI2, GRObeta (CXCL2), MnSOD and GCP-2 (CXCL6) may represent new targets for treatments specifically tailored to osteoarthritis.

Genetic variability of Tomato spotted wilt virus in Australia and validation of real time RT-PCR for its detection in single and bulked leaf samples

The potential for large-scale use of a sensitive real time reverse transcription polymerase chain reaction (RT-PCR) assay was evaluated for the detection of Tomato spotted wilt virus (TSWV) in single and bulked leaf samples by comparing its sensitivity with that of DAS-ELISA. Using total RNA extracted with RNeasy (R) or leaf soak methods, real time RT-PCR detected TSWV in all infected samples collected from 16 horticultural crop species (including flowers, herbs and vegetables), two arable crop species, and four weed species by both assays. In samples in which DAS-ELISA had previously detected TSWV, real time RT-PCR was effective at detecting it in leaf tissues of all 22 plant species tested at a wide range of concentrations. Bulk samples required more robust and extensive extraction methods with real time RT-PCR, but it generally detected one infected sample in 1000 uninfected ones. By contrast, ELISA was less sensitive when used to test bulked samples, once detecting up to I infected in 800 samples with pepper but never detecting more than I infected in 200 samples in tomato and lettuce. It was also less reliable than real time RT-PCR when used to test samples from parts of the leaf where the virus concentration was low. The genetic variability among Australian isolates of TSWV was small. Direct sequencing of a 587 bp region of the nucleoprotein gene (S RNA) of 29 isolates from diverse crops and geographical locations yielded a maximum of only 4.3% nucleotide sequence difference. Phylogenetic analysis revealed no obvious groupings of isolates according to geographic origin or host species. TSWV isolates, that break TSWV resistance genes in tomato or pepper did not differ significantly in the N gene region studied, indicating that a different region of the virus genome is responsible for this trait.

Design, development, and use of molecular primers and probes for the detection of Gluconacetobacter species in the pink sugarcane mealybug

Molecular tools for the species-specific detection of Gluconacetobacter sacchari, Gluconacetobacter diazotrophicus, and Gluconacetobacter liquefaciens from the pink sugarcane mealybug (PSMB) Saccharicoccus sacchari Cockerell (Homiptera: Pseudococcidae) were developed and used in polymerase chain reactions (PCR) and in fluorescence in situ hybridizations (FISH) to better understand the microbial diversity and the numerical significance of the acetic acid bacteria in the PSMB microenvironment. The presence of these species in the PSMB occurred over a wide range of sites, but not in all sites in sugarcane-growing areas of Queensland, Australia, and was variable over time. Molecular probes for use in FISH were also designed for the three acetic acid bacterial species, and shown to be specific only for the target species. Use of these probes in FISH of squashed whole mealybugs indicated that these acetic acid bacteria species represent only a small proportion of the microbial population of the PSMB. Despite the detection of Glac. sacchari, Glac. diazotrophicus, and Glac. liquefaciens by PCR from different mealybugs isolated at various times and from various sugarcane-growing areas in Queensland, Australia, these bacteria do not appear to be significant commensals in the PSMB environment.

A new algorithm for the detection of intercluster galaxy filaments using galaxy orientation alignments

We present a new algorithm for detecting intercluster galaxy filaments based upon the assumption that the orientations of constituent galaxies along such filaments are non-isotropic. We apply the algorithm to the 2dF Galaxy Redshift Survey catalogue and find that it readily detects many straight filaments between close cluster pairs. At large intercluster separations (> 15 h(-1) Mpc), we find that the detection efficiency falls quickly, as it also does with more complex filament morphologies. We explore the underlying assumptions and suggest that it is only in the case of close cluster pairs that we can expect galaxy orientations to be significantly correlated with filament direction.

An implementation of nonlinear multiuser detection in Rayleigh fading channel

A blind nonlinear interference cancellation receiver for code-division multiple-access- (CDMA-) based communication systems operating over Rayleigh flat-fading channels is proposed. The receiver which assumes knowledge of the signature waveforms of all the users is implemented in an asynchronous CDMA environment. Unlike the conventional MMSE receiver, the proposed blind ICA multiuser detector is shown to be robust without training sequences and with only knowledge of the signature waveforms. It has achieved nearly the same performance of the conventional training-based MMSE receiver. Several comparisons and experiments are performed based on examining BER performance in AWGN and Rayleigh fading in order to verify the validity of the proposed blind ICA multiuser detector.

Enhanced detection-guided NLMS estimation of sparse FIR-modeled signal channels

In various signal-channel-estimation problems, the channel being estimated may be well approximated by a discrete finite impulse response (FIR) model with sparsely separated active or nonzero taps. A common approach to estimating such channels involves a discrete normalized least-mean-square (NLMS) adaptive FIR filter, every tap of which is adapted at each sample interval. Such an approach suffers from slow convergence rates and poor tracking when the required FIR filter is "long." Recently, NLMS-based algorithms have been proposed that employ least-squares-based structural detection techniques to exploit possible sparse channel structure and subsequently provide improved estimation performance. However, these algorithms perform poorly when there is a large dynamic range amongst the active taps. In this paper, we propose two modifications to the previous algorithms, which essentially remove this limitation. The modifications also significantly improve the applicability of the detection technique to structurally time varying channels. Importantly, for sparse channels, the computational cost of the newly proposed detection-guided NLMS estimator is only marginally greater than that of the standard NLMS estimator. Simulations demonstrate the favourable performance of the newly proposed algorithm. © 2006 IEEE.

Of snakes and flowers: Does preferential detection of pictures of fear-relevant animals in visual search reflect on fear-relevance?

Previous research in visual search indicates that animal fear-relevant deviants, snakes/spiders, are found faster among non fear-relevant backgrounds, flowers/mushrooms, than vice versa. Moreover, deviant absence was indicated faster among snakes/spiders and detection time for flower/mushroom deviants, but not for snake/spider deviants, increased in larger arrays. The current research indicates that the latter 2 results do not reflect on fear-relevance, but are found only with flower/mushroom controls. These findings may reflect on factors such as background homogeneity, deviant homogeneity, or background-deviant similarity. The current research removes contradictions between previous studies that used animal and social fear-relevant stimuli and indicates that apparent search advantages for fear-relevant deviants seem likely to reflect on delayed attentional disengagement from fear-relevance on control trials.

The detection of environmental autoinducing peptide quorum-sensing genes from an uncultured Clostridium sp in landfill leachate reactor biomass

Aims: To elucidate whether a dominant uncultured clostridial (Clostridium thermocellum-like) species in an environmental sample (landfill leachate), possesses an autoinducing peptide (AIP) quorum-sensing (QS) gene, although it may not be functional. Methods and Results: A modified AIP accessory gene regulator (agr)C PCR protocol was performed on extracted DNA from a landfill leachate sample (also characterized by 16S rRNA gene cloning) and the PCR products were cloned, sequenced and phylogenetically analysed. It appeared that two agrC gene phylotypes existed, most closely related to the C. thermocellum agrC gene, differing by only 1 bp. Conclusions: It is possible to specifically identify and characterize the agrC AIP QS gene from uncultured Firmicutes (C. thermocellum-like) bacteria derived from environmental (landfill leachate) sample. Significance and Impact of the Study: This is the first successful attempt at identifying AIP QS genes from a cellulolytic environment (landfill). The agrC gene was identified as being most closely related to the C. thermocellum agrC gene, the same bacterium identified as being dominant, according to 16S rRNA gene cloning and subsequently fluorescence in situ hybridization analyses, in the same biomass.