Reduced thrombomodulin in human peripheral nerve microvasculature

Thrombomodulin (TM), a vascular endothelial receptor, terminates the actions of thrombin and accelerates activated protein C formation. TM is ubiquitous throughout the systemic microcirculation but is reduced in brain regions predisposed to lacunar infarction. We investigated whether TM is present within human nerve and differentially expressed according to vessel caliber and proximity to the blood-nerve barrier. Vascular endothelial TM was detected on sural nerve biopsies with immunohistochemistry. The proportion of TM-positive microvessels was expressed relative to total von Willebrand factor (vWF)-positive vessels. Although vWF was detectable in all microvessels, TM expression was absent from the perineurial vessels. TM was detected in 47% (15-80%, 95% confidence level) of larger epineurial arterioles, in 43% (30-61%) of smaller epineurial vessels, and in 30% (19-47%) of endoneurial vessels. These findings demonstrate that TM is present in human nerve microvasculature but is regionally deficient in proximity to the blood-nerve barrier, which may predispose nerve to microvascular ischemia in inflammatory/prothrombotic conditions.     

Effect of moderate dehydration on torque,electromyography, and mechanomyography

The purpose of the present investigation was to test the hypotheses that the mechanomyographic (MMG) signal would be affected by hydration status due to changes in the intra- and extracellular fluid content (which could affect the degree of fluid turbulence), changes in the filtering properties of the tissues between the MMG sensor and muscle, and changes in torque production that may accompany dehydration. Ten subjects (age 22.5 +/- 1.6 years) were tested for maximal isometric (MVC), submaximal isometric (25, 50, and 75%MVC), and maximal concentric isokinetic muscle strength of the biceps brachii in either a euhydrated or dehydrated state while the electromyographic (EMG) and MMG signals were recorded. Separate three-way and two-way ANOVAs indicated no change in torque, EMG amplitude, EMG mean power frequency (MPF), MMG amplitude, and MMG MPF with dehydration. The lack of dehydration effect suggests that MMG may be more reflective of the intrinsic contractile processes of a muscle fiber (torque production) or the motor control mechanisms (reflected by the EMG) than the tissues and fluids surrounding the muscle fiber.     

The role of acetylation in the mutagenicity of the antitumor agent, batracylin

The role of acetylation in the genotoxicity of the heterocyclicamine, batracylin, was evaluated in Salmonella typhimurium strainsexpressing various levels of N-and O-acetyltransferase activity.A significant correlation was observed between batracylin-inducedmutagenicity and bacterial N-acetyltransferase activity. Strainswith the greatest capacity for N-acetylating batracylin (YG1012 and YG 1024) were the most sensitive to the mutagenic effectsof the drug. The number of revertants/nmol batracylin and theformation of acetylbatracylin were     

Superior mesenteric artery and renal artery blood flow velocity measurements in neonates: Technique and interobserver reliability

The objective of this study was to establish the interobserver reliability for superior mesenteric artery (SMA) and renal artery (RA) Doppler blood flow velocity (BFV) measurements in neonates. Forty-two clinically stable infants were enrolled, mean (SD) gestational age 33 (2) weeks, birthweight 2.00 (0.54) kg, postnatal age 10 (11) days. Doppler recordings were made by two trained observers. The SMA and RA were studied with a 5.0-MHz phased array transducer. The optimal spectral trace from each artery containing a minimum of five consecutive waveforms was analysed. The peak systolic velocity (PS), end diastolic velocity (ED) and mean peak velocity (MV) were measured and the time-averaged mean velocity (TAV) and waveform indices were calculated. Using the intraclass correlation coefficient (ICC) the estimates of interobserver reliability for different measurements varied from 0.40 to 0.83. Substantial agreement was obtained between observers in the TAV, PS, ED and MV; the ICC varied from 0.72 to 0.83 demonstrating that Doppler BFV measurements of the SMA and RA are reliable in neonates.