Reflux in young patients: comparison of voiding US of the bladder and retrovesical space with echo enhancement versus voiding cystourethrography for diagnosis

PURPOSE: To compare the usefulness of voiding US of the bladder and retrovesical space with echo enhancement with that of voiding cystourethrography (VCUG) for diagnosis of vesicoureteral reflux (VUR) and to assess patient tolerance of the echo-enhancing agent. MATERIALS AND METHODS: One hundred eighty-eight patients (aged 5 days to 20 years) referred for investigation of VUR underwent voiding US with echo enhancement, which was followed by VCUG in 110 patients (226 kidney-ureter units). After US of the renal tract, the bladder was filled with normal saline solution. Then SU U 508 A, a galactose-based, microbubble-containing echo-enhancing agent, was administered. Reflux was diagnosed when microbubbles appeared in the ureter or pelvicalyceal system. RESULTS: VUR was detected in 80 of the units with one (n = 18) or both (n = 62) methods. All grades of reflux were identified. In 15 units, reflux diagnosed at voiding US was not observed at VCUG; the reverse was true in three units. In 208 (92%) of the 226 kidney-ureter units, there was concordance between the two methods regarding the diagnosis or exclusion of VUR. The echo-enhancing agent was well tolerated. CONCLUSION: SH U 508 A enhanced voiding US is as good as VCUG in the detection or exclusion of VUR and thus will make it possible to reduce the number of children having to be exposed to ionizing radiation.     

Top-down lipidomic screens by multivariate analysis of high-resolution survey mass spectra

Direct profiling of total lipid extracts on a hybrid LTQ Orbitrap mass spectrometer by high-resolution survey spectra clusters species of 11 major lipid classes into 7 groups, which are distinguished by their sum compositions and could be identified by accurately determined masses. Rapid acquisition of survey spectra was employed as a "top-down" screening tool that, together with the computational method of principal component analysis, revealed pronounced perturbations in the abundance of lipid precursors within the entire series of experiments. Altered lipid precursors were subsequently identified either by accurately determined masses or by in-depth MS/MS characterization that was performed on the same instrument. Hence, the sensitivity, throughput and robustness of lipidomics screens were improved without compromising the accuracy and specificity of molecular species identification. The top-down lipidomics strategy lends itself for high-throughput screens complementing ongoing functional genomics efforts.     

Panel summary: spontaneous echo contrast in patients with mechanical heart valve implants

Three study sites along the roads with different automobile traffic densities were selected and cattle milk samples were collected every month from all the three sites. Lead concentration in samples were determined through atomic absorption spectrometer. Milk collected from area of heavy traffic contained 4.6-7.2 ppm of Pb, which is much higher than its permissible limit (0.3 ppm) according to FDA.     

Synthesis and some pharmacological properties of deamino(4-threonine,8-D-arginine)vasopressin and deamino(8-D-arginine)vasopressin, highly potent and specific antidiuretic peptides, and (8-D-arginine)vasopressin and deamino-arginine-vasopressin

Deamino[4-threonine,8-D-arginine]vasopressin (dTDAVP), deamino[8-D-arginine]vasopressin (dDAVP), [8-D-arginine[vasopressin (DAVP), and deamino-arginine-vasopressin (dAVP) were synthesized by the solid-phase method and tested for their biological activities. dTDAVP has an antidiuretic potency of 793+/-95 units/mg and undetectable vasporessor activity, less than 0.02unit/mg. The antidiuretic-pressor (A/P) ratio of dTDAVP is greater than 39 000. dDAVP has an antidiuretic potency of 1200+/-126 units/mg and a vasopressor potency of 0.39+/-0.02; its A/P ratio is thus 3000. DAVP has an antidiuretic potency of 253+/-44 units/mg, a vasopressor potency of 1.1+/-0.04 units/mg, and an A/P ratio of 240. The A/P ratios of dDAVP and DAVP are much higher than those originally reported. dAVP has an antidiuretic potency of 1745+/-385 units/mg, a vasopressor potency of 346+/-13, and an A/P ratio of 5; values are in general agreement with those in the literature. Threonine subsitution has thus brought about a significant enhancement in antidiuretic specificity, a finding entirely consistent with earlier observations that enhancement of lipophilicity at position 4 alone or in combination in arginine-vasopressin can lead to enhanced antidiuretic specificity.     

传统刺绣技术的创新--带有缝编线迹的三维结构材料

描述了由德国图林根纺织研究所（TIVT）和Gerber镂空织物与绣品公司合作开发的几种不同用途的三维结构刺绣样品。借助刺绣技术可创制出客户定制的灵活多变的中空结构。这些纺织品可用于汽车内饰、纤维复合材料、医用制品及智能服等。     

Sizing emboli in blood using pulse Doppler ultrasound. II. Effectsof beam refraction

For pt.I see ibid., vol.43, no.6, p.572-80 (1996). A theoretical and numerical study of the acoustic field intensity within a curved flow conduit having (1) diameter similar to the wavelength of the interrogating frequency and (2) speed of sound mismatch with the surrounding medium is presented. The field intensity is shown to vary significantly and in a monotonic fashion across the flow conduit. The resulting insonation of emboli transiting through the Doppler sample volume is explored with a Monte Carlo study of the behavior of the embolus to blood power ratio (EBR). The numerical simulation findings are shown to be in good agreement with previously reported experimental results. A method is explored for estimating embolus diameter when this refraction artifact is present, and shown to yield excellent results when applied to experimental data. Further work toward clinical application of these results is discussed     

Time-scale detection of microemboli in flowing blood with Dopplerultrasound

Small formed elements and gas bubbles in flowing blood, called microemboli, can be detected using Doppler ultrasound. In this application, a pulsed constant-frequency ultrasound signal insonates a volume of blood in the middle cerebral artery, and microemboli moving through its sample volume produce a Doppler-shifted transient reflection. Current detection methods include searching for these transients in a short-time Fourier transform (STFT) of the reflected signal. However, since the embolus transit time through the Doppler sample volume is inversely proportional to the embolus velocity (Doppler-shift frequency), a matched-filter detector should in principle use a wavelet transform, rather than a short-time Fourier transform, for optimal results. Closer examination of the Doppler shift signals usually shows a chirping behavior apparently due to acceleration or deceleration of the emboli during their transit through the Doppler sample volume. These variations imply that a linear wavelet detector is not optimal. We apply linear and quadratic time-frequency and time-scale detectors to a set of noise-corrupted embolus data. Our results show improvements of about 1 dB using the time-scale detectors versus an STFT-based detector signifying that embolus detection is best approached as a time-scale problem. A time-scale-chirp detector is also applied and is found to have the overall best performance by about 0.5-0.7 dB while coming fairly close (about 0.75 dB) to a theoretical upper bound.     

Compartment pressure monitoring during intramedullary fixation of tibial fractures

Twenty-six legs in 25 patients were monitored prospectively for compartment pressures during intramedullary nailing of open and closed tibial shaft fractures. Twenty-three patients were treated within 24 hours of admission. Twenty-three unreamed and three reamed intramedullary rods were utilized. Compartment pressures were measured initially, following fracture reduction, and during reaming. Pressures were also measured at the completion of nailing with the ankle dorsiflexed and at rest (plantar flexed) to determine positional effects on compartment pressures. Nine fractures (35%) were found to have persistently elevated pressures (> 40 mm Hg) and underwent immediate four-compartment fasciotomy. The remaining group of 17 fractures (65%) was monitored throughout the intraoperative period. No patient monitored intraoperatively developed postoperative compartment syndrome.     

Sizing emboli in blood using pulse Doppler ultrasound. I.Verification of the EBR model

An experiment to verify a theory describing ultrasound backscattering from emboli in flowing blood is presented. The theoretical predictions for the backscattered power versus embolus size are based on the measurement of the embolus to blood ratio (EBR) of backscattered acoustic power. This tool is necessary for in vivo clinical application because it removes the need to characterize attenuation and reflection loss in heterogeneous tissue. The experiment presented utilizes a customized ultrasound pulse Doppler that is capable of interrogating a sample volume with two different frequencies concurrently. A flow circuit including a 3.6-mm-diameter conduit in polyacrylamide gel in which emboli are observed with the dual frequency Doppler is described. The flow within the circuit has acoustic backscatter coefficient similar to blood due to a calibrated concentration of 31.1-μ diameter polystyrene microspheres. Polystyrene microsphere “emboli” having nominal diameters of 161 and 239 μ are placed in this flow loop and time series Doppler shift signatures are recorded. These signatures are investigated and a refraction artifact hypothesis is proposed to explain systematic deviation of the signatures away from theoretically expected results. Results show that gross discrimination of embolus size is feasible