Histology of tendon and enthesis - suitable techniques for specific research questions.

The musculoskeletal system consists of different components comprising a wide range of tissue types, with tendons being one part. Tendon degeneration or rupture have a high prevalence in all age groups, often with poor outcomes of surgical treatment such as chronic pain and high re-tear rates. Therefore, much effort has been directed to further develop diagnostic and therapeutic methods as well as reconstruction techniques, including using adequate placeholders or implants. Diagnostic approaches and advanced stages of preclinical studies will inevitably include histological examination of the pathologically affected tissue. The present study presents adequate tendon-related, histological techniques, including the embedding of soft- and hard-tissue samples in different media. Consideration is also given to samples containing residual implant materials or having been subjected to standard staining protocols and immunohistochemical procedures. The study further examines cells and tendon structure to detect degenerative, fibrotic or inflammatory conditions and possible foreign-body responses to implanted materials. Infraspinatus tendons from preclinical studies carried on rat and sheep samples, as well as human biceps tendon samples, have been used as example materials.

Comparison of different harvesting methods from the flat and long bones of rats.

Different harvesting methods have been developed for bony augmentation before implantation. The aim of the present study was to assess the viability of endochondral (femoral) and membranous (mandibular) bone cells harvested by different methods under standard conditions in an animal model, and to investigate the surface of the bone in the harvested area. Samples of mandibular and femoral bone were harvested using a drilling burr, a piezoelectrical device, or a Safescraper(®). Blocks of bone that had been harvested with cutting forceps were used as controls. The size of the samples was measured and they were examined by conventional microscopy and immunohistochemical analysis; osteoblast-like cells were also cultured. The surface of the harvested area was analysed with scanning and conventional microscopy. There was no significant difference between mandibular and femoral bone in the size of particles harvested, but bone chips were significantly smaller when a drilling device had been used in both harvesting areas. Viability of cells in these smaller particles was significantly less than among cells harvested with a piezoelectrical device or Safescraper(®). Scanning microscopy showed a smooth bony surface where a drilling burr or piezoelectrical device had been used, whereas small disruptions were observed after the Safescraper(®) had been used. Harvesting of particulate bone is feasible using a drilling burr, piezoelectrical device, or Safescraper(®) from mandibular and femoral bone. The piezoelectrical device and the Safescraper(®) gave comparable results concerning the viability of osteoblast-like cells, and so are preferred to a drilling burr.

[Farquhar disease. Reduced phagocyte function in a 9-year-old girl with erythrophagocytic lymphohistiocytosis]. / M. Farquhar. Verminderte Phagozytenfunktion bei einem 9 Monate alten Mädchen mit erythrophagozytärer Lymphohistiozytose.

We report phagocyte function tests in a female infant with familial hemophagozytotic lymphohistiocytosis. Chemiluminescence and killing of Saccharomyces cerevisiae by monocytes and granulocytes before chemotherapy and in remission were examined. Patients' monocytes and granulocytes showed a markedly reduced chemiluminescence and killing capacity irrespective of the stage of disease.