Epidermal Transglutaminase (TGase 3) Is Required for Proper Hair Development, but Not the Formation of the Epidermal Barrier

Transglutaminases (TGase), a family of cross-linking enzymes present in most cell types, are important in events as diverse as cell-signaling and matrix stabilization. Transglutaminase 1 is crucial in developing the epidermal barrier, however the skin also contains other family members, in particular TGase 3. This isoform is highly expressed in the cornified layer, where it is believed to stabilize the epidermis and its reduction is implicated in psoriasis. To understand the importance of TGase 3 in vivo we have generated and analyzed mice lacking this protein. Surprisingly, these animals display no obvious defect in skin development, no overt changes in barrier function or ability to heal wounds. In contrast, hair lacking TGase 3 is thinner, has major alterations in the cuticle cells and hair protein cross-linking is markedly decreased. Apparently, while TGase 3 is of unique functional importance in hair, in the epidermis loss of TGase 3 can be compensated for by other family members

Effect of tissue-harvesting site on yield of stem cells derived from adipose tissue: implications for cell-based therapies

The stromal vascular fraction (SVF) of adipose tissue contains an abundant population of multipotent adipose-tissue-derived stem cells (ASCs) that possess the capacity to differentiate into cells of the mesodermal lineage in vitro. For cell-based therapies, an advantageous approach would be to harvest these SVF cells and give them back to the patient within a single surgical procedure, thereby avoiding lengthy and costly in vitro culturing steps. However, this requires SVF-isolates to contain sufficient ASCs capable of differentiating into the desired cell lineage. We have investigated whether the yield and function of ASCs are affected by the anatomical sites most frequently used for harvesting adipose tissue: the abdomen and hip/thigh region. The frequency of ASCs in the SVF of adipose tissue from the abdomen and hip/thigh region was determined in limiting dilution and colony-forming unit (CFU) assays. The capacity of these ASCs to differentiate into the chondrogenic and osteogenic pathways was investigated by quantitative real-time polymerase chain reaction and (immuno)histochemistry. A significant difference (P = 0.0009) was seen in ASC frequency but not in the absolute number of nucleated cells between adipose tissue harvested from the abdomen (5.1 ± 1.1%, mean ± SEM) and hip/thigh region (1.2 ± 0.7%). However, within the CFUs derived from both tissues, the frequency of CFUs having osteogenic differentiation potential was the same. When cultured, homogeneous cell populations were obtained with similar growth kinetics and phenotype. No differences were detected in differentiation capacity between ASCs from both tissue-harvesting sites. We conclude that the yield of ASCs, but not the total amount of nucleated cells per volume or the ASC proliferation and differentiation capacities, are dependent on the tissue-harvesting site. The abdomen seems to be preferable to the hip/thigh region for harvesting adipose tissue, in particular when considering SVF cells for stem-cell-based therapies in one-step surgical procedures for skeletal tissue engineering

A large-scale multicentre study of patient skin doses in interventional cardiology: dose-area product action levels and dose reference levels.

For 318 patients in 8 different Belgian hospitals, the entire skin-dose distribution was mapped using a grid of 70 thermoluminescence dosimeters per patient, allowing an accurate determination of the maximum skin dose (MSD). Dose-area product (DAP) values, exposure parameters and geometry, together with procedure, patient and cardiologist characteristics, were also registered. Procedures were divided into two groups: diagnostic procedures (coronary angiography) and therapeutic procedures (dilatation, stent, combined procedures (e.g. coronary angiography + dilatation + stent)). The mean value of the MSD was 0.310 Gy for diagnostic and 0.699 Gy for therapeutic procedures. The most critical projection for receiving the MSD is the LAO90 (left anterior oblique) geometry. In 3% of cases, the MSD exceeded the 2 Gy dose threshold for deterministic effects. Action levels in terms of DAP values as the basis for a strategy for follow-up of patients for deterministic radiation skin effects were derived from measured MSD and cumulative DAP values. Two DAP action levels are proposed. A first DAP action level of 125 Gy cm(2) corresponding to the dose threshold of 2 Gy would imply an optional radiopathological follow-up depending on the cardiologist's decision. A second DAP action level of 250 Gy cm(2) corresponding to the 3 Gy skin dose would imply a systematic follow-up. Dose reference levels - 71.3 Gy cm(2) for diagnostic and 106.0 Gy cm(2) for therapeutic procedures - were derived from the 75 percentile of the DAP distributions. As a conclusion, we propose that total DAP is registered in patient's record file, as it can serve to improve the follow-up of patients for radiation-induced skin injuries