Zeitschrift für Zytologie und Histologie

A growing body of literature suggests that phase separation within polymer mixtures drives many biological processes. The formation of membraneless organelles by liquid-liquid phase separation is thought to play a variety of roles in cell metabolism, gene regulation, and signalling. One of the characteristics of these systems is that they are poised at phase transition boundaries, which makes them perfectly suited to elicit robust cellular responses to often very small changes in the cell's "environment". Recent findings suggest that phase separation not only plays a role in wall patterning, hydration, and stress relaxation during growth, but may also be a driving force for cell wall expansion in the semisolid environment of plant cell walls.

Tendon injuries are a worldwide health issue that affects millions of people each year. Tendons' properties make natural rehabilitation a complex and time-consuming process. Tissue engineering is a new discipline that has emerged as a result of the advancements in the fields of biomaterials, bioengineering, and cell biology. Diverse approaches have been proposed within this discipline. The obtained results are promising, as more complex and natural tendon-like structures are obtained. The nature of the tendon and the conventional treatments that have been used thus far are highlighted in this review. Then, a comparison of the various tendon tissue engineering approaches proposed to date is made, focusing on each of the elements required to obtain structures that allow adequate regeneration of the tendon: growth factors, cells, scaffolds and techniques for scaffold development.

Routine 5 μm H&E-stained lung sections were utilized to investigate the capability of histomorphometry for determining pneumonia severity using a murine influenza model. Lung density was measured using the NIH ImageJ software program and the results for binary digital images were compared to corresponding results for semiquantitative pneumonia severity scoring. Lung samples from mice exposed (inoculated controls or IC) or not exposed (non-inoculated controls or NC) to influenza virus were evaluated at 3-, 5-, 7-, 10- and 15-days following exposure. On day 15 the mean density and standard deviation for NC at 25-x were 106 ± 23.6 and for IC 154.9 ± 36.3, and the difference was significant (p ≥ 0.05). Using 400-x measurements NC values were 68.1 ± 8.5 and IC 96.8 ± 16.1 and significant. Significant differences were present at either magnification in the occurrence of “morphometric pneumonia” (defined as density values above the upper 95% confidence interval of controls). Density measurements @ 25-x were moderately correlation with pneumonia severity scores (correlation coefficient or r=0.55), but measurements @ 400-x were strongly correlation with scores (r=0.75). The approach provides a simple, rapid, and inexpensive method for the quantification of pneumonia using free digital software and routine microscopy. It also provides a quantitative method for validation of semiquantitative severity scoring of pneumonia.