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The administration of iodinated contrast media (CM) can cause microcirculatory disorder leading to acute renal dysfunction. In a prospective, randomized investigation two CM (Iodixanol vs Iopromide) were compared in 16 pigs. Each animal received 10 intra-aortal injections (5 ml Iodixanol or 4.32 ml Iopromide). Microcirculation was assessed using contrast-enhanced ultrasound (CEUS) directly on the kidney surface using time-to-peak (TTP) and blood-volume-analysis. Macroscopic observations were documented. Post mortem residual CM distribution in the kidneys was detected using X-ray. TTP was significantly prolonged over the descending vasa recta of the Iopromide group. This coincided with a visible marble-like pattern on the kidney surface occurring in 30 out of 80 Iopromide-injections but in 4 out of 80 Iodixanol-injections (p = 0.007). The blood volume over the entire kidney did not change after Iodixanol-application, but decreased by about 6.1% after Iopromide-application. The regional blood volume in the renal cortex showed a tendency to decrease by about 13.5% (p = 0.094) after Iodixanol-application, and clearly decreased by about 31.7% (p = 0.022) after Iopromide-application. The study revealed a consistent influence of repeated injections of two different CM on the kidney perfusion using three different imaging methods (CEUS analysis, macroscopic observation and X-ray analysis).

Background: Intra-arterial administration of radiographic contrast media (CM) is discussed to impair renal perfusion. The pathogenesis of contrast-induced Nephropathy (CIN) is still not clarified., Objective: This trial was performed to prove the effects of two CM with different molecular structure on renal perfusion., Methods: A prospective, randomized study on 16 pigs was designed to compare the outcome after application of a low-osmolar iodinated CM (770 mOsm/kg H2O - Group1) and an iso-osmolar iodinated CM (290 mOsm/kg H2o - Group2).Color Coded Doppler Sonography (LOGIQ E9, GE, Milwaukee, USA) was applied for measuring the Renal Resistive Index (RRI) before and after the first, fifth, and tenth bolus of CM. Statistics was performed using analysis of variance for repeated measurements with the Factor "CM"., Results: All flow spectra were documented free of artifacts and Peak Systolic Velocity (PSV), Enddiastolic Velocity (EDV) and RRI respectively could be calculated. Mean PSV in Group 1 led to a decrease while in Group 2 PSV showed a significant increase after CM (p = 0,042). The course of the mean EDV in both groups deferred accordingly (p = 0,033). Mean RRI over time significantly deferred in both groups (p = 0,001). It showed a biphasic course in Group 2 and a decrease over time in Group 2., Conclusion: While iso-osmolar CM induced an increase of PSV and EDV together with a decrease of RRI, low-osmolar CM could not show this effect or rather led to the opposite.

Monoclonal antibodies are produced in cultured hybridoma cell lines, but these cells tend to be unstable; it is therefore necessary to rescue the corresponding genetic information. Here we describe an improved method for the amplification of antibody variable gene (V-gene) information from murine hybridoma cells using a panel of specific, non-degenerate primers. This primer set allows sequences to be rescued from all murine V-genes, except the lambda light chain genes, which rarely contribute to murine immune diversity. We tested the primers against a range of antibodies and recovered specific amplification products in all cases. The heavy and light chain variable regions were subsequently joined by a two-step cloning strategy or by splice overlap extension PCR.

Compared with conventional modes of patient-initiated mechanical ventilation, respiratory mechanical unloading aims at improving the match between ventilator pressure profiles and the specific derangements in lung mechanics. This may reduce lung barotrauma. The ventilator pressure increases either in proportion to the volume or to the flow of spontaneous breathing (elastic or resistive unloading), thereby selectively decreasing elastic or resistive work of breathing. The clinician sets a gain of increase in pressure per unit of volume or flow. In an attempt to develop criteria for selecting an appropriate gain, we investigated the effects of unloading using increasing gains that either partially compensated or overcompensated lung elastance or resistance. We studied spontaneously breathing, anesthetized, and tracheotomized rabbits. Compared with continuous positive airway pressure, respiratory unloading decreased the electromyographic activity of the diaphragm and increased minute ventilation in normal (n = 5) and surfactant-depleted (n = 6) animals when the gain was partially compensating. Fluctuations in systemic blood pressure associated with breathing decreased. The end-expiratory lung volume remained unchanged. Overcompensation of lung elastic recoil during elastic unloading with an excessive gain caused large tidal volumes associated with a cyclic decrease in blood pressure. Overcompensation of resistance induced oscillations. Complete inhibition of spontaneous breathing occurred with a further increase in gain. We conclude that respiratory unloading with an appropriate gain enhances the effect of diaphragmatic muscle activity on ventilation. A stable breathing pattern ensues whenever a regular spontaneous effort is present. However, excessive gain causes large tidal volumes during elastic unloading or oscillations during resistive unloading.