A Signal Processing Approach for Detection of Hemodynamic Instability before Decompensation

Advanced hemodynamic monitoring is a critical component of treatment in clinical situations where aggressive yet guided hemodynamic interventions are required in order to stabilize the patient and optimize outcomes. While there are many tools at a physician’s disposal to monitor patients in a hospital setting, the reality is that none of these tools allow hi-fidelity assessment or continuous monitoring towards early detection of hemodynamic instability. We present an advanced automated analytical system which would act as a continuous monitoring and early warning mechanism that can indicate pending decompensation before traditional metrics can identify any clinical abnormality. This system computes novel features or bio-markers from both heart rate variability (HRV) as well as the morphology of the electrocardiogram (ECG). To compare their effectiveness, these features are compared with the standard HRV based bio-markers which are commonly used for hemodynamic assessment. This study utilized a unique database containing ECG waveforms from healthy volunteer subjects who underwent simulated hypovolemia under controlled experimental settings. A support vector machine was utilized to develop a model which predicts the stability or instability of the subjects. Results showed that the proposed novel set of features outperforms the traditional HRV features in predicting hemodynamic instability.     

Peripheral blood cytotoxic gammadelta T lymphocytes from patients with human immunodeficiency virus type 1 infection and AIDS lyse uninfected CD4+ T cells,and their cytocidal potential correlates with viral load

Progression of human immunodeficiency virus type 1 (HIV-1) infection in humans is marked by declining CD4+-T-cell counts and increasing virus load (VL). Cytotoxic T lymphocytes (CTL) play an important role in the lysis of HIV-infected cells, especially during the early phase of asymptomatic infection. CTL responses in the later phase of disease progression may not be as effective since progressors with lower CD4+-T-cell counts have consistently higher VL despite having elevated CTL counts. We hypothesized that, apart from antiviral effects, some CTL might also contribute to AIDS pathogenesis by depleting CD4+ T cells and that this CTL activity may correlate with the VL in AIDS patients. Therefore, a cross-sectional study of 31 HIV-1-infected patients at various clinical stages was carried out. Purified CTL from these donors as well as HIV-seronegative controls were used as effectors against different human cell targets by using standard 51Cr release cytolytic assays. A direct correlation between VL and CTL-mediated, major histocompatibility complex (MHC)-unrestricted lysis of primary CD4+-T-cell, CEM.NKR, and K562 targets was observed. CD4+-T-cell counts and duration of infection also correlated with MHC-unrestricted cytolytic activity. Our data clearly show that gammadelta CTL are abnormally expanded in the peripheral blood of HIV-infected patients and that the Vdelta1 subset of gammadelta T cells is the main effector population responsible for this type of cytolysis. The present data suggest that gammadelta CTL can contribute to the depletion of bystander CD4+ T cells in HIV-infected patients as a parallel mechanism to HIV-associated immunopathogenesis and hence expedite AIDS progression.     

Elevated levels of circulating interleukin-18 in human immunodeficiency virus-infected individuals: role of peripheral blood mononuclear cells and implications for AIDS pathogenesis

Originally identified as the gamma interferon-inducing factor, interleukin-18 (IL-18) was rediscovered as a proinflammatory cytokine related to the IL-1 family of cytokines that plays an important role in both innate and adaptive immune responses against viruses and intracellular pathogens. Despite its importance in inducing and regulating immune responses, relatively little is known about its production in HIV infection. We report here significantly (P < 0.05) elevated levels of this cytokine in the sera of human immunodeficiency virus (HIV)-infected/AIDS patients compared to those of HIV-seronegative healthy persons. Surprisingly, the peripheral blood mononuclear cells (PBMC) from HIV-infected/AIDS patients were compromised in the ability to upregulate IL-18 gene expression and produce this cytokine with and without lipopolysaccharide (LPS) stimulation. A significant positive correlation (P < 0.05) existed between the concentration of IL-18 in serum and its production from PBMC of HIV-seronegative healthy individuals but not those of HIV-infected/AIDS patients. Furthermore, the patients' PBMC expressed relatively reduced levels of activated caspase-1 constitutively as well as in response to LPS stimulation. Our data suggest the involvement of transforming growth factor beta (TGF-beta) in suppressing IL-18 production from the patients' PBMC for the following reasons. (i) In in vitro studies it suppressed the production of IL-18 from PBMC. (ii) Its levels were significantly higher in the plasma of patients compared to that of control subjects. (iii) A significant negative correlation existed between the concentrations of TGF-beta in plasma and of IL-18 in serum of the patients. The elevated levels of IL-18 in the serum of HIV-infected individuals may contribute to AIDS pathogenesis, whereas its compromised production from their PBMC in response to stimuli may reduce their innate defense to opportunistic intracellular pathogens.     

A smart bioconjugate of alginate and pectinase with unusual biological activity toward chitosan

The commercial preparation of pectinase (Pectinex Ultra SP-L) was conjugated to alginate by noncovalent interactions by employing 1% alginate during the conjugation protocol. The optimum "immobilization efficiency" was 0.76. The pH optimum and the thermal stability of the enzyme remained unchanged upon conjugation with alginate. The soluble bioconjugate showed a 3-fold increase in V(max)/K(m) as compared to the free enzyme when the smart biocatalyst was used for chitosan hydrolysis. Time course hydrolysis of chitosan thus showed higher conversion of chitosan into reducing oligosaccharides/sugars. The smart bioconjugate could be reused five times without any detectable loss of chitosanase activity.     

Alginate beads as an affinity material for alpha amylases

Calcium-alginate beads were found to bind a variety of enzymes in a nonspecific fashion. However, alpha amylases from porcine pancreas, Bacillus subtilis (BAN 240L) and wheat germ bound at a significant level and B. subtilis and wheat germ amylases could be eluted with 1M maltose. The wheat germ alpha amylase could be purified 45 fold with 70% recovery. The SDS - PAGE pattern showed significant purification by this single step strategy.     

Investigation of Genes Encoding Calcineurin B-Like Protein Family in Legumes and Their Expression Analyses in Chickpea (Cicer arietinum L.)

Calcium ion (Ca²⁺) is a ubiquitous second messenger that transmits various internal and external signals including stresses and, therefore, is important for plants’ response process. Calcineurin B-like proteins (CBLs) are one of the plant calcium sensors, which sense and convey the changes in cytosolic Ca²⁺-concentration for response process. A search in four leguminous plant (soybean, Medicago truncatula, common bean and chickpea) genomes identified 9 to 15 genes in each species that encode CBL proteins. Sequence analyses of CBL peptides and coding sequences (CDS) suggested that there are nine original CBL genes in these legumes and some of them were multiplied during whole genome or local gene duplication. Coding sequences of chickpea CBL genes (CaCBL) were cloned from their cDNAs and sequenced, and their annotations in the genome assemblies were corrected accordingly. Analyses of protein sequences and gene structures of CBL family in plant kingdom indicated its diverse origin but showed a remarkable conservation in overall protein structure with appearance of complex gene structure in the course of evolution. Expression of CaCBL genes in different tissues and in response to different stress and hormone treatment were studied. Most of the CaCBL genes exhibited high expression in flowers. Expression profile of CaCBL genes in response to different abiotic stresses and hormones related to development and stresses (ABA, auxin, cytokinin, SA and JA) at different time intervals suggests their diverse roles in development and plant defence in addition to abiotic stress tolerance. These data not only contribute to a better understanding of the complex regulation of chickpea CBL gene family, but also provide valuable information for further research in chickpea functional genomics.     

Transcriptional profiling of bovine intervertebral disc cells: implications for identification of normal and degenerate human intervertebral disc cell phenotypes

Introduction  

Nucleus pulposus (NP) cells have a phenotype similar to articular cartilage (AC) cells. However, the matrix of the NP is clearly different to that of AC suggesting that specific cell phenotypes exist. The aim of this study was to identify novel genes that could be used to distinguish bovine NP cells from AC and annulus fibrosus (AF) cells, and to further determine their expression in normal and degenerate human intervertebral disc (IVD) cells.     

Luminescence studies of perturbation of tryptophan residues of tubulin in the complexes of tubulin with colchicine and colchicine analogues

Tubulin, a heterodimeric (alphabeta) protein, the main constituent of microtubules, binds efficiently with colchicine (consisting of a trimethoxybenzene ring, a seven-member ring and methoxy tropone moiety) and its analogues, viz., demecolcine and AC [2-methoxy-5-(2',3',4'-trimethoxyphenyl)tropone]. Tubulin contains eight tryptophan (Trp) residues at A21, A346, A388, A407, B21, B103, B346, and B407 in the two subunits. The role of these eight Trp residues in this interaction and also their perturbation due to binding have been explored via time-resolved fluorescence at room temperature and low-temperature (77 K) phosphorescence in a suitable cryosolvent. Both the time-resolved fluorescence data and 77 K phosphorescence spectra indicate that the emitting residues move toward a more hydrophobic and less polar environment after complex formation. The environment of emitting Trps in the complex also becomes slightly more heterogeneous. Our analysis using the experimental results, the calculation of the accessible surface area (ASA) of all the Trps in the wild type and tubulin-colchicine complex [Ravelli, R. B. G., et al. (2004) Nature 428, 198-202], the distance of the Trp residues from the different moieties of the colchicine molecule, the knowledge of the nature of the immediate residues (<5 A) present near each Trp residue, and the calculation of the intramolecular Trp-Trp energy transfer efficiencies indicate that Trp A346, Trp A407, Trp B21, and Trp B407 are the major contributors to the emission in the free protein, while Trp B21 and Trp B103 are mainly responsible for the emission of the complexes. A comparative account of the photophysical aspects of the drug molecules bound to protein in aqueous buffer and in buffer containing 40% ethylene glycol has been presented. The quantum yield and average lifetime of fluorescence in tubulin and its complexes with colchicine are used to predict the possible donors and the energy transfer (ET) efficiency in the ET process from Trps to colchicine in the complex. This study is a unique attempt to identify the Trp residues contributing to the emission in the free protein and in a complex of a multi-Trp protein with a drug molecule without performing the mutation of the protein.