Anterograde Injection of Alteplase Salvages Deep Inferior Epigastric Perforator Flap in Reconstructive Breast Surgery.

The DIEP flap is currently considered the gold standard for autologous reconstructive breast surgery. Postoperative flap failure due to microvascular postanastomotic thrombotic occlusion is a rare but severe complication. Alteplase, a thrombolytic agent typically used in the setting of an ischemic stroke, myocardial infarction, or pulmonary embolism, has also been injected into the microcirculation of flaps as a rescue procedure due to imminent flap loss. The purpose of this article is to provide an overview and detailed guidance for such a thrombolytic procedure due to suspected thrombotic microsurgical failure in free flap surgery. We report the case of a 43-year-old woman who underwent unilateral breast reconstruction with a DIEP flap at our department. Approximately 12 hours postoperatively, an arterial inflow problem was suspected and revision surgery was performed. Peripheral flap perfusion remained absent without an obvious cause and distal thrombosis was assumed to be present. Therefore, alteplase was gradually injected into the arterial pedicle in the anterograde direction just distal to the anastomosis while clamping the artery proximally. About 3 hours after selective flap thrombolysis, microcirculation of the flap was successfully restored without complications. Anterograde injection of alteplase can successfully salvage a free flap. To our knowledge, evidence for optimal dosing and delivery of alteplase for the treatment of thrombosed DIEP flaps has not been published to date. Our approach presents a therapeutic option that both maximizes alteplase concentration in the flap and minimizes the dosage required for flap salvage to significantly reduce systemic adverse effects.

Preliminary survey of matrix effects in the Microwave-sustained, Inductively Coupled Atmospheric-pressure Plasma (MICAP).

Matrix effects caused by Na and Al in the nitrogen Microwave-sustained, Inductively Coupled, Atmospheric-pressure Plasma (MICAP) were investigated. Easily ionizable elements, such as Na, can suppress or enhance the analyte signal; Al is shown here to produce a similar effect. The influence of these matrices was examined for 18 emission lines of 8 analyte atoms and ions having a wide range of excitation and ionization energies. The plasma operating conditions were fixed during all experiments at a total nitrogen flow of 19.4Lmin-1 and a microwave power of 1.5kW. An Fe solution was used to determine the excitation temperature of the plasma by the Boltzmann plot method at selected matrix concentrations. In addition, vertical emission profiles of the plasma were measured. The matrix effect becomes worse at higher concentrations of an easily ionizable element. The effect is caused not only by a shift in ionization equilibrium but also by a possible change in plasma ionization temperature. Correction methods to reduce the matrix effects were tested and are discussed.

Electromagnetic behavior of spatial terahertz wave modulators based on reconfigurable micromirror gratings in Littrow configuration.

Efficient, high speed spatial modulators with predictable performance are a key element in any coded aperture terahertz imaging system. For spectroscopy, the modulators must also provide a broad modulation frequency range. In this study, we numerically analyze the electromagnetic behavior of a dynamically reconfigurable spatial terahertz wave modulator based on a micromirror grating in Littrow configuration. We show that such a modulator can modulate terahertz radiation over a wide frequency range from 1.7 THz to beyond 3 THz at a modulation depth of more than 0.6. As a specific example, we numerically simulated coded aperture imaging of an object with binary transmissive properties and successfully reconstructed the image.

Laboratory and field studies on a new sensor for dissolved N2O.

Nitrous oxide (N2O) is a strong greenhouse gas, whose atmospheric concentration has been continuously increasing for more than 200 years. One major source is wastewater treatment plants (WWTPs), where N2O emissions should either be minimized or pushed to levels where exploitation in biogas combustion engines becomes efficient. Both these strategies require online control of the N2O concentrations in the liquid as well as in the gas phase. For this purpose, we propose a system for membrane extraction of the gas from the liquid phase, which then allows for a subsequent gas-phase analysis, which we perform by photoacoustic spectroscopy. We compare different theoretical calculations of the extraction efficiency, based either on a straightforward mathematical model or on a finite element simulation. The comparison of results with measurements produced on a well-defined model system shows good accordance. Based on the outcome, a field probe was developed and tested on a WWTP, yielding results comparable to the one achieved by GC reference analysis. Graphical abstract Gas extraction from liquids, e.g. from a wastewater treatment plant, for online gas monitoring.

Photoacoustic Spectroscopy for the Quantification of N2O in the Off-Gas of Wastewater Treatment Plants.

Different configurations of photoacoustic (PA) setups for the online-measurement of gaseous N2O, employing semiconductor lasers at 2.9 and 4.5 µm, were developed and tested. Their performance was assessed with respect to the analysis of N2O emissions from wastewater treatment plants. For this purpose, the local N2O emissions of a wastewater treatment bioreactor was sampled by a dedicated mobile sampling device, and the total N2O emissions were analyzed in the gastight headspace of the bioreactor. We found that the use of a quantum-cascade laser emitting at about 4.53 µm, operated in a wavelength modulation mode, in combination with a conventional longitudinal PA cell yielded the highest sensitivity (<100 ppbv). However, we also observed a strong cross-sensitivity to humidity, which can be explained by increased V-T relaxation. This observation in combination with the limited dynamic range (max conc. ∼ 3000 ppmv) led us to the use of the less-sensitive but spectroscopically more robust 2.9 µm laser. A detection limit below 1 ppmv, a dynamic range of more than 4 orders of magnitude, no influence of humidity or any other substance relevant to the off-gas analysis, as well as a comparable low price of the laser source made it the ideal tool for N2O analyses of the off-gas of a wastewater treatment plant. Such a system was implemented successfully in a full-scale wastewater treatment plant. The results regarding the comparison of different PA setups can be transferred to other systems, and the optimum performance can be selected according to the specific demands.

Evaluation of the impact of diffraction on image reconstruction in single-pixel imaging systems.

In single-pixel coded aperture terahertz-imaging, the individual pixel size in the spatial terahertz modulator is usually comparable to the terahertz wavelength in order to obtain a sufficient spatial image resolution. Therefore, diffraction plays an important role in the imaging process and must be accurately taken into account when the image is computationally retrieved. For this reason, we analyzed the impact of diffraction from the spatial terahertz modulator on the quality of the reconstructed image in single-pixel coded aperture imaging. We observed that the most important fraction of the image information is already contained in the zero order diffracted radiation. Higher diffraction orders do not contain enough information to retrieve the image from them solely, yet can contribute to an improved image quality when added to the zero order information.

Multisensory brand search: How the meaning of sounds guides consumers' visual attention.

Building on models of crossmodal attention, the present research proposes that brand search is inherently multisensory, in that the consumers' visual search for a specific brand can be facilitated by semantically related stimuli that are presented in another sensory modality. A series of 5 experiments demonstrates that the presentation of spatially nonpredictive auditory stimuli associated with products (e.g., usage sounds or product-related jingles) can crossmodally facilitate consumers' visual search for, and selection of, products. Eye-tracking data (Experiment 2) revealed that the crossmodal effect of auditory cues on visual search manifested itself not only in RTs, but also in the earliest stages of visual attentional processing, thus suggesting that the semantic information embedded within sounds can modulate the perceptual saliency of the target products' visual representations. Crossmodal facilitation was even observed for newly learnt associations between unfamiliar brands and sonic logos, implicating multisensory short-term learning in establishing audiovisual semantic associations. The facilitation effect was stronger when searching complex rather than simple visual displays, thus suggesting a modulatory role of perceptual load. (PsycINFO Database Record

Photoacoustics of single laser-trapped nanodroplets for the direct observation of nanofocusing in aerosol photokinetics.

Photochemistry taking place in atmospheric aerosol droplets has a significant impact on the Earth's climate. Nanofocusing of electromagnetic radiation inside aerosols plays a crucial role in their absorption behaviour, since the radiation flux inside the droplet strongly affects the activation rate of photochemically active species. However, size-dependent nanofocusing effects in the photokinetics of small aerosols have escaped direct observation due to the inability to measure absorption signatures from single droplets. Here we show that photoacoustic measurements on optically trapped single nanodroplets provide a direct, broadly applicable method to measure absorption with attolitre sensitivity. We demonstrate for a model aerosol that the photolysis is accelerated by an order of magnitude in the sub-micron to micron size range, compared with larger droplets. The versatility of our technique promises broad applicability to absorption studies of aerosol particles, such as atmospheric aerosols where quantitative photokinetic data are critical for climate predictions.

The use of confidence intervals in reporting orthopaedic research findings.

Conflict between clinical importance and statistical significance is an important problem in medical research. Although clinical importance is best described by asking for the effect size or how much, statistical significance can only suggest whether there is any difference. One way to combine statistical significance and effect sizes is to report confidence intervals. We therefore assessed the reporting of confidence intervals in the orthopaedic literature and factors influencing this frequency. In parallel, we tested the predictive value of statistical significance for effect size. In a random sample of predetermined size, we found one in five orthopaedic articles reported confidence intervals. Participation of an individual trained in research methods increased the odds of doing so fivefold. The use of confidence intervals was independent of impact factor, year of publication, and significance of outcomes. The probability of statistically significant results to predict at least a 10% between-group difference was only 69% (95% confidence interval, 55%-83%), suggesting that a high proportion of statistically significant results do not reflect large treatment effects. Confidence intervals could help avoid such erroneous interpretation by showing the effect size explicitly.

Proximal deep venous thrombosis following PTA of the superficial femoral artery--an obligation to disclose a complication that is rarely taken into account.

We report two cases of femoral vein thrombosis after arterial PTA and subsequent pressure stasis. We discuss the legal consequences of these complications for information policies. Because venous thrombembolism following an arterial PTA might cause serious sequel or life threatening complications, there is a clear obligation for explicit information of the patients about this rare complication.

Characterization of soluble vs membrane-bound human placental 5'-nucleotidase.

Three forms of 5'-nucleotidase purified from human placenta (two membrane-bound forms, one sensitive and one resistant to cleavage by phosphatidylinositol-specific phospholipase C, as well as a soluble form) had the same molecular weight before (73,000 Da) and after (56,000 Da) digestion with N-glycosidase F and showed similar amino acid compositions, N-terminal amino acid sequences, and KMs for IMP (9.6 to 11.9 microM). Thus, these three forms of 5'-nucleotidase appear to have very similar structures. The form sensitive to phosphatidylinositol-specific phospholipase C contained nearly 1 mol myo-inositol/mol of protein as determined by mass spectrometry, indicating a glycosyl phosphatidylinositol membrane anchor. Soluble 5'-nucleotidase contained a similar quantity of myo-inositol, suggesting that it was previously membrane-anchored via glycosyl phosphatidylinositol. The form resistant to phosphatidylinositol-specific phospholipase C contained less myo-inositol, leaving open the possibility of a third form of 5'-nucleotidase with a conventional transmembrane anchor.

Production and characterization of monoclonal antibodies to the glycosyl phosphatidylinositol-anchored lymphocyte differentiation antigen ecto-5'-nucleotidase (CD73).

A panel of monoclonal antibodies to the 69 kDa glycosyl phosphatidylinositol anchored lymphocyte differentiation antigen ecto-5'-nucleotidase (ecto-5'-NT, CD73) was produced using highly purified human placental 5'-NT as immunogen. Antibodies 1E9.28.1 and 7G2.2.11 inhibit soluble placental 5'-NT activity and recognize lymphocyte CD73 in indirect immunofluorescence and immunoprecipitation assays. In addition, 1E9.28.1 induces vigorous T cell proliferation in the presence of submitogenic doses of phorbol myristate and F(ab')2 goat anti-mouse Ig. Both antibodies can be used to purify the three major forms of placental 5'-NT by affinity chromatography. By two-color immunofluorescence, CD73 was found to be expressed on 19 +/- 5% of CD3+, 11 +/- 4% of CD4+, 51 +/- 14% of CD8+, 25 +/- 8% of CD28+, 15 +/- 5% of CD29+, 27 +/- 7% of CD45RA+, and 70 +/- 6% of CD19+ lymphocytes. Within T cells, CD73 expression is restricted to the CD28+ subset. Thus, CD73 is found on subsets of both T and B lymphocytes, with the highest expression on B cells and CD8+ T cells. In sections of hyperplastic tonsil, CD73 expression is restricted to the small lymphocytes of the follicular mantle zone, a small subset of extrafollicular lymphocytes situated within the epithelium of the tonsillar crypt, and to follicular dendritic cells within the lower part of the "light-zone." CD73 is also detected on subsets of endothelial cells of capillaries and venules and the basal layer of non-keratinizing squamous epithelium and transitional cell type mucosa of many tissues. Given the tissue distribution of CD73, along with its glycosyl phosphatidylinositol membrane anchoring and the observation that some CD73 antibodies are mitogenic, we propose that this interesting antigen may play a role in cell activation, lymphocyte homing, and/or cell adhesion.

NMR studies identify four intermediate states of ATPase and the ion transport cycle of sarcoplasmic reticulum Ca2+-ATPase.

Water proton nuclear relaxation measurements are used to detect and characterize four distinct intermediate states for Gd3+ bound to Ca2+ sites of sarcoplasmic reticulum Ca2+-ATPase in complexes with ATP analogues. In the absence of nucleotides, Gd3+ binds to two occluded Ca2+ transport sites on Ca2+-ATPase which have a low accessibility to solvent water. In the presence of the nonhydrolyzable ATP analogue, Co(NH3)4AMPPCP, a new state for bound Gd3+ (still occluded and with fewer waters of hydration) is observed. In the presence of Co(NH3)4ATP or ATP, two additional states for bound Gd3+ are detected in the NMR studies. The first of these probably represents an intermediate state for bound Gd3+ during ATP hydrolysis. The latter is the most occluded Gd3+ site yet observed in these studies and is probably analogous to the highly occluded E1-P state observed with CrATP [(1987) Biochim. Biophys. Acta 898, 313-322].

NMR relaxation measurements detect four intermediate states of ATPase and transport cycle of sarcoplasmic reticulum Ca2+-ATPase.

At least four of the intermediate states of Ca2+-ATPase (and presumably ion transport) can be trapped and characterized using water proton relaxation measurements. Gd3+ binds to two occluded Ca2+ transport sites on Ca2+-ATPase which have a low accessibility to solvent water. In the presence of the MgATP analogue Co(NH3)4AMPPCP, a new state for bound Gd3+ with one less water of hydration) is observed. In the presence of Co(NH3)4ATP or ATP, two additional states for bound Gd3+ are detected by NMR, the first of which probably represents an intermediate state of ATP hydrolysis. The latter is the most occluded Gd3+ site yet observed in these studies and corresponds to the highly occluded E1-P state observed with CrATP (Vilsen and Andersen, Biochim. Biophys. Acta 898, 313 (1987).

Occluded calcium sites in soluble sarcoplasmic reticulum Ca2+-ATPase.

Rabbit muscle sarcoplasmic reticulum Ca2+-ATPase has been shown to bind gadolinium ion (Gd3+) at two high affinity Ca2+ sites (Stephens, E. M., and Grisham, C. M. (1979) Biochemistry 18, 4876-4885). Gd3+ bound at these sites exhibits an unusually long electron spin relaxation time, consistent with occlusion of these sites and reduced contact with solvent H2O. In this report, the nature of the Gd3+ sites was examined in preparations of the enzyme solubilized with the detergent C12E8. The frequency dependence of water proton relaxation in solutions containing the solubilized Ca2+-ATPase yields dipolar correlation times, tau c, for the 1H-Gd3+ interaction of 1.04 X 10(-9) s for Gd3+ bound at site 1 and 1.98 X 10(-9) s for Gd3+ bound at site 2. The correlation time itself is frequency dependent below 30 MHz, indicating that the correlation time is dominated by the electron spin relaxation time of bound Gd3+. The long values of the correlation time found in the present study are consistent with a poor accessibility of these Gd3+ sites (particularly site 2) to solvent water molecules. Analytical ultracentrifugation and molecular sieve high performance liquid chromatography indicated that the active fraction of the soluble Ca2+-ATPase was monomeric. Thus occlusion of the Ca2+ sites in this enzyme is largely dependent on the tertiary structure of the monomeric ATPase and does not appear to depend on multimeric membrane structures.

Five doubly unsaturated metabolites of valproic acid in urine and plasma of patients on valproic acid therapy.

The urine and plasma of epileptic patients receiving therapeutic doses of valproic acid (2-propyl- pentanoic acid) was found to contain five doubly unsaturated metabolites of valproic acid, which were identified as their trimethylsilyl derivatives by GC/MS. A series of reference substances was synthesized but only two of them were identical with native metabolites: 2(2-propenyl)-4-pentenoic acid (= 4.4'-diene) and E-2-propyl-2.4- pentadienoic acid (E-2.4-diene). The mass-spectra of the five native metabolites are given. Preliminary quantitative data obtained from four groups of patients indicate increased formation of doubly unsaturated metabolites when valproic acid-induced side-effects are present, and in cases of fatal hepatic failure. The 4.4'-diene has hitherto been found only in fatal cases with hepatic injury. Quantitative data are presented as % of the sum of valproic acid plus all its detected metabolites.