Identification of Serum MicroRNA Signatures for Diagnosis of Mild Traumatic Brain Injury in a Closed Head Injury Model

Wars in Iraq and Afghanistan have highlighted the problems of diagnosis and treatment of mild traumatic brain injury (mTBI). MTBI is a heterogeneous injury that may lead to the development of neurological and behavioral disorders. In the absence of specific diagnostic markers, mTBI is often unnoticed or misdiagnosed. In this study, mice were induced with increasing levels of mTBI and microRNA (miRNA) changes in the serum were determined. MTBI was induced by varying weight and fall height of the impactor rod resulting in four different severity grades of the mTBI. Injuries were characterized as mild by assessing with the neurobehavioral severity scale-revised (NSS-R) at day 1 post injury. Open field locomotion and acoustic startle response showed behavioral and sensory motor deficits in 3 of the 4 injury groups at day 1 post injury. All of the animals recovered after day 1 with no significant neurobehavioral alteration by day 30 post injury. Serum microRNA (miRNA) profiles clearly differentiated injured from uninjured animals. Overall, the number of miRNAs that were significantly modulated in injured animals over the sham controls increased with the severity of the injury. Thirteen miRNAs were found to identify mTBI regardless of its severity within the mild spectrum of injury. Bioinformatics analyses revealed that the more severe brain injuries were associated with a greater number of miRNAs involved in brain related functions. The evaluation of serum miRNA may help to identify the severity of brain injury and the risk of developing adverse effects after TBI.     

Altered membrane fluidity in rat hepatocytes during endotoxic shock

Steady-state fluorescence anisotropy measurements of the fluorescent hydrocarbon probe 1,6-diphenyl-1,3,4-hexatriene (DPH) were carried out in isolated hepatocytes of saline control andSalmonella enteritidis endotoxin (20 mg/kg) injected rats. Statistically significant differences were observed in the fluorescent anisotropy (r_s) and membrane microviscosity ( ) values of control (r_s=0.107±0.004 (SEM), =0.98±0.08, n±6) versus endotoxin injected rat hepatocytes (r_s=0.134±0.005, =1.43±0.08, n=6, p<0.001) at 37°C. Fluidity was similarly lower in the isolated plasma membrane preparations from endotoxin-injected rat livers relative to control livers. When endotoxin-injected rats were treated with the calcium channel-blocker diltiazem, the anisotropy and microviscosity values were comparable to thos eobtained from control rats (r_s=0.152±0.003, =1.00±0.003, n=6). These measurements were made in animals five hours after endotoxin had been injected, and thus represent thein vivo effects of bacterial endotoxins. Temperature scan studies of DPH from 5–40°C revealed that the membrane fluidity of endotoxin-injected rat hepatocytes was significantly lower than control hepatocytes at all temperatures investigated. The data suggest that endotoxin alters the membrane fluidity of hepatocytes, and that calcium-channel blockers can prevent the alteration. Our previous studies have shown that calcium channel blocker prevented endotoxin induced alterations in hepatic cellular regulation of Ca²⁺. Thus, cellular calcium homeostasis may be important in the maintenance of membrane fluidity and other membrane-associated transport functions. (Mol Cell Biochem121: 143–148, 1993)     

Recognition of Nonstructural Protein Peptides by Cytotoxic T Lymphocytes Raised against Japanese Encephalitis Virus

We have previously reported that Lyt2⁺ cytotoxic T lymphocytes (CTL) can be raised against Japanese encephalitis virus (JEV) in BALB/c mice. In order to confirm the presence of H-2K^d-restricted CTL and to examine their cross-recognition of West Nile virus (WNV), we tested the capacity of anti-JEV CTL to lyse uninfected syngeneic target cells that were pulsed with synthetic peptides. The sequence of the synthetic peptides was predicted based upon the H-2K^d binding consensus motif. We show here that preincubation of uninfected syngeneic targets (P388D1) with JEV NS1- and NS3-derived peptides [NS1 (891-899) and NS3 (1804-1812)], but not with JEV NS5-derived peptide [NS5 (3370-3378)], partially sensitized them for lysis by polyclonal anti-JEV CTL. These results indicate the CTL recognition of NS1- and NS3-derived peptides of JEV.     

Determination of terazosin in human plasma, using high-performance liquid chromatography with fluorescence detection

A selective, sensitive, rapid and reproducible high-performance liquid chromatographic method for the determination of terazosin in plasma is described. The structurally related compound prazosin was used as an internal standard. The method comprises extraction with methylene chloride followed by chromatography on a C₁₈ reversed-phase column. The compounds were detected using spectrofluorimetry. The absolute recoveries were more than 90% with a minimal detection of 1 ng/ml and calibration curve was linear between 1 and 80 ng/ml.     

RNA facilitates RecA-mediated DNA pairing and strand transfer between molecules bearing limited regions of homology

The RecA protein ofEscherichia coli catalyzes homologous pairing and strand exchange between a wide range of molecules showing nucleotide sequence complementarity, including a linear duplex and a single-stranded DNA molecule. We demonstrate that RecA can promote formation of joint molecules when the duplex contains an RNA/DNA hairpin and a single-stranded circle serves as the pairing partner. A chimeric RNA/DNA hairpin can be used to form stable joint molecules with as little as 15 bases of shared homology as long as the RNA stretch contains complementarity to the circle. The joint molecule bears some resemblance to a triple helical structure composed of RNA residues surrounded by two DNA strands which are in a parallel orientation. Evidence is presented that supports the notion that short stretches of RNA can be used in homologous pairing reactions at lengths below that required for DNA-DNA heteroduplex formation.     

Laser anemometry measurements of pulsatile flow past aortic valve prostheses

Experimental results are presented on physiological pulsatile flow past caged ball and tilting disc aortic valve prostheses mounted in an axisymmetric chamber incorporated in a mock circulatory system. The measurements of velocity profiles and turbulent normal stresses during several times in a cardiac cycle were obtained using laser-Doppler anemometry. Our results show that with increased angle of opening for the tilting disc valves, a large but locally confined vortex is observed along the wall in the minor flow region throughout most of the cardiac cycle. The turbulent normal stresses measured downstream to the tilting disc in the minor flow region parallel to the tilt axis were found to be larger than those measured downstream to the caged ball valves. Comparison of measurements with steady flow at flow rates comparable to peak pulsatile flow rate show that the turbulent normal stresses are larger by a factor of two in pulsatile flow with a frequency of 1.2 Hz.     

Steady flow development past valve prostheses in a model human aorta—II. Tilting disc valves

The flow development in the model human aorta with uniform entry as well as with centrally occuluding valves mounted at the root of the aorta was described in Part I of this two-paper sequence. Part II deals with the flow development in the model aorta with tilting disc valves mounted at the root of the aorta. Bjork-Shiley and Hall-Kaster tilting disc valves were mounted in three different orientations with respect to the root of the aorta. The velocity profiles and turbulent stresses were measured with laser-Doppler anemometry. Our results under steady flow conditions in the model human aorta show quantitatively that the flow development in the ascending aorta as well as in the brachio-cephalic artery are strongly dependent on the orientation of the tilting disc valves. With the valves tilting towards the outer wall of curvature, our results suggest a tendency for flow separation at the flow divider region of the brachio-cephalic artery.