An exploratory study on the effect of mechanical stress on particle formation in monoclonal antibody infusions

Monoclonal antibody infusions (mAb-i) are administered for the treatment of various diseases. They are often transported over long distances from the compounding site to the site of administration. However, transport studies are typically carried out with the original drug product but not with compounded mAb-i. To address this gap, the impact of mechanical stress on the formation of subvisible/nanoparticles in mAb-i was investigated by dynamic light scattering and flow imaging microscopy. Different mAb-i concentrations were subjected to vibrational orbital shaking and stored at 2-8°C up to 35 days. The screening revealed that pembrolizumab and bevacizumab infusions show the highest propensity for particle formation. Especially bevacizumab at low concentrations exhibited an increase in particle formation. Because of the unknown health risks associated with the long-term application of subvisible particles (SVPs)/nanoparticles in infusion bags, stability studies carried out in the frame of licensing application procedures should also focus on SVP formation in mAb-i. In general, pharmacists should minimize the time of storage and mechanical stress during transport, especially in the case of low-concentrated mAb-i. Moreover, if siliconized syringes are used, they should be washed once with saline solution to minimize particle entry.

The maggot therapy supply chain: a review of the literature and practice

Maggot therapy (MT) is the clinical application of living fly larvae for the treatment of non-healing wounds and wounds that require debridement. This systematized and expanded literature review is the first study to investigate MT through the conceptual and disciplinary framework of supply chain management. The review of 491 selected academic papers was expanded to include the grey literature and online information resources to construct a first-pass theory of the medicinal maggot supply chain. It shows that the literature to date has focused on isolated discussions of echelon-specific issues such as diet improvement and sterilization protocols in the production echelon, and the relative effectiveness of medicinal maggot application methods in the treatment echelon. There is little knowledge in the public domain regarding the transport and distribution of medicinal maggots, but existing supply chains for vaccines, blood and pathology specimens may provide learning and supply chain integration opportunities. Maggot therapy knowledge across the treatment echelon is generally substantive but there is still insufficient knowledge regarding patients' and health care providers' attitudes toward the therapy, and their experiences of receiving and administering MT. Moreover, there is no research concerned with the humane disposal of medicinal flies during production and after treatment.

Superstatistical analysis and modelling of heterogeneous random walks

Stochastic time series are ubiquitous in nature. In particular, random walks with time-varying statistical properties are found in many scientific disciplines. Here we present a superstatistical approach to analyse and model such heterogeneous random walks. The time-dependent statistical parameters can be extracted from measured random walk trajectories with a Bayesian method of sequential inference. The distributions and correlations of these parameters reveal subtle features of the random process that are not captured by conventional measures, such as the mean-squared displacement or the step width distribution. We apply our new approach to migration trajectories of tumour cells in two and three dimensions, and demonstrate the superior ability of the superstatistical method to discriminate cell migration strategies in different environments. Finally, we show how the resulting insights can be used to design simple and meaningful models of the underlying random processes.

Conventional methods to quantify the migratory behaviour of cells assume that underlying parameters are constant. Mark et al. apply a superstatistical approach to extract time-dependent parameters of motile cells, and demonstrate an enhanced ability to distinguish between different migration strategies.

Anatomical study of the perforating vessels of the lower leg

Difficulty of soft tissue defects of the lower leg demands the development of new methods to treat such defects. The aim of this study is the examination of perforators and the various ways of blood supply to the skin in the lower leg. Provided with certain regularity, we would be able to cure soft-tissue defects also in the difficult zone of the distal segment and on the dorsum of the foot not harming vessels and not affecting mobility of muscles. Subcutaneous island-flaps supplied by perforating vessels could replace free flaps. By saving the crural fascia of 10 lower legs we flayed layers of skin and fat, marked the perforating vessels with pins, and photographed and documented them. Specimens were divided into a proximal, an intermediate and a distal segment, each of them subdivided into a medial, lateral and dorsal section. The perforators, which can be classified as septocutaneous and musculocutaneous vessels, followed a reproducible pattern all over the lower leg. All vessels were sufficient in number as well as in size. Additionally these perforators can easily be identified by colour-coded sonography. The knowledge that perforators in the lower leg occur regularly enables the development of a new operative approach in therapy of soft-tissue defects in this region with the advantage, that the vessels used can be selected preoperatively.

Inhibition of the phosphate self-exchange flux in human erythrocytes and erythrocyte ghosts

The phosphate self-exchange flux in resealed erythrocyte ghosts and in amphotericin B (5.5 microM) permeabilized erythrocytes has been studied. The phosphate self-exchange flux exhibits an S-shaped concentration dependence and a self-inhibition in permeabilized red cells while in erythrocyte ghosts no self-inhibition of the phosphate flux has been observed. The apparent half-saturation constants and the apparent Hill coefficients were assessed by the double reciprocal Hill plots of 1/JP versus 1/[P]n. The phosphate half-saturation constants amount to approx. 125 mM in ghosts and to about 75 mM in permeabilized cells while the apparent Hill coefficients amount to 1.15 and to 1.65 (pH 7.2, 25 degrees C), respectively. Both chloride and sulfate elicit a mixed-type inhibition of the phosphate self-exchange flux. In permeabilized cells, chloride and sulfate shift the flux optimum towards higher phosphate concentrations and reduce the apparent Hill coefficients. In erythrocyte ghosts, the apparent Hill coefficients are insensitive to these anions. The double reciprocal Hill plots indicate a mixed-type inhibition of the phosphate self-exchange flux by DNDS, salicylate and dipyridamole and a noncompetitive inhibition of the phosphate self-exchange flux by phlorhizin. By contrast, the Hill-Dixon plots for chloride and sulfate indicate a competitive inhibition of the phosphate self-exchange flux in erythrocyte ghosts and a mixed-type inhibition in permeabilized cells and provide Hill coefficients of greater than unity for chloride and sulfate. The Dixon plots for DNDS, salicylate, phlorhizin and dipyridamole show a noncompetitive inhibition of the phosphate flux and provide apparent Hill coefficients of 0.95-1.0 for inhibitor binding. Using the Debye-Hückel theory, the effects of ionic strength upon phosphate transport and inhibitor binding can be eliminated. The results of our studies provide strong evidence for the assumption that electrostatic forces are involved in phosphate transport and in inhibitor binding.