Observation of Collagen-Containing Lesions After Hematoma Resolution in Intracerebral Hemorrhage

Background and Purpose: The classic presentation of chronic (stage III) hemorrhagic stroke lesions is a fluid-filled cavity. In one of the most commonly used animal models of intracerebral hemorrhage (ICH), we noticed additional solid material within the chronic lesion. We examined the composition of those chronic ICH lesions and compared them with human autopsy cases. Methods: ICH was induced in rats by the injection of collagenase in the striatum. Tissue sections after hematoma resolution corresponding to 3 different chronic time points—28, 42, and 73 to 85 days post-ICH—were selected. Human autopsy reports at the University Hospital of Zurich were searched between 1990 and 2019 for ICH, and 3 chronic cases were found. The rat and human sections were stained with a variety of histopathologic markers. Results: Extensive collagenous material was observed in the chronic lesion after hematoma resolution in both the rat model and human autopsy cases. Additional immunostaining revealed that the material consisted primarily of a loose network of collagen 3 intermingled with occasional GFAP (glial fibrillary acidic protein)-positive processes and collagen 4. Conclusions: A key feature of the chronic ICH lesion is a loose network of collagen 3. The collagenase rat model reproduces the morphology and composition of the chronic human ICH lesion. While identifying new features of ICH lesion pathology, these results are important for treatment and recovery strategies.

Conjunctival stromal tumour (COST): anterior-segment OCT findings

Conjunctival stromal tumour (COST) is a recently described rare conjunctival tumour of mesenchymal origin with only four publications describing a handful of cases thus far. In this report, we describe the anterior-segment optical coherence tomography (AS-OCT) characteristics in a case of COST for the first time, in addition to the clinical and histopathological characteristics. The AS-OCT showed an elevated, dome-shaped hyporeflective homogenous lesion in the conjunctival stroma lined by hyperreflective outer layer with mild posterior shadowing, consistent with histological description of a paucicellular tumour with large myxoid collagenous material inside. Immunohistochemistry showed positive CD34 and vimentin but negative S100 and smooth muscle actin, thereby differentiating it from conjunctival myxoma.

Hydraulic characteristic of collagen

Hydraulic characteristic of collagen. Czech J. Food Sci., 33: 479–485. The hysteresis of a hydraulic characteristic while pumping an aqueous solution of collagen through a pipe at gradually increasing and decreasing flow rates (hysteresis means that the pressure drop curve during increased flow rate is above the pressure drop during decreasing flow rate) was observed. The problem was initiated by industry and by demand for an on-line recording of rheological properties of collagenous material used for extrusion of collagen casings. The Herschel-Bulkley rheological model was capable to describe rheograms in a wide range of deformation rates; however it was not able to describe and explain the hysteresis. As a possible reason thixotropic properties were identified and the hydraulic characteristic was calculated using a thixotropic generalisation of the Herschel-Bulkley model. The developed 1D numerical model can be applied for on-line modelling of transient flows of incompressible thixotropic food materials (startup flow) and at a limited range of flow rates it is also capable to describe the hysteresis of hydraulic characteristics.

Development of a Bioreactor to Culture Tissue Engineered Ureters Based on the Application of Tubular OPTIMAIX 3D Scaffolds

Regenerative medicine, tissue engineering and biomedical research give hope to many patients who need bio-implants. Tissue engineering applications have already been developed based on bioreactors. Physiological ureter implants, however, do not still function sufficiently, as they represent tubular hollow structures with very specific cellular structures and alignments consisting of several cell types. The aim of this study was to a develop a new bioreactor system based on seamless, collagenous, tubular OPTIMAIX 3D prototype sponge as scaffold material for ex-vivo culturing of a tissue engineered ureter replacement for future urological applications. Particular emphasis was given to a great extent to mimic the physiological environment similar to the in vivo situation of a ureter. NIH-3T3 fibroblasts, C2C12, Urotsa and primary genitourinary tract cells were applied as co-cultures on the scaffold and the penetration of cells into the collagenous material was followed. By the end of this study, the bioreactor was functioning, physiological parameter as temperature and pH and the newly developed BIOREACTOR system is applicable to tubular scaffold materials with different lengths and diameters. The automatized incubation system worked reliably. The tubular OPTIMAIX 3D sponge was a suitable scaffold material for tissue engineering purposes and co-cultivation procedures.