Biomedical subjects
Publications and source records attributed to U M Gross.
Comparative electron microscopic examination of ganglions (from the tendon sheaths and joint capsules of the hand) as well as that of newly formed tendon sheaths (after resection of digital flexors and their tendon sheaths) indicate that both are the result of an adaptive effect of the mesenchyma which enables the formation of a new synovial organ in the presence of an adequate stimulus.
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The bioactive glass ceramic Ceravital forms a physicochemical bonding with bone which is capable of withstanding stress caused by tension. This glass ceramic may already be put to clinical use as replacement for minor osseous parts. However, physical data are limited for maximum stress withstanding or gracile whole ceramic implants. In this study, metal cylinders from an alloy of CoCrMo are initially coated with a bio-compatible adhesive layer of enamel, approximately 0,2 to 0,3 mm thick. The adhesive strength of this kind of enamel amounts to about 120 to 140 kp/cm2. After the enamelling process, the glass ceramic is pressed into the enamel in granules at a particle size of 100 to 200 micrometer. As the first results show, this new process is suitable for the combination of metal implant stability and tissue compatibility of glass ceramic.
A high percentage of plastic keratoprosthesis is rejected again or intraocular infections occur because there is a cleft-like open junction between anterior chamber and lacrimal film. Only the ketratoprosthesis by Strampelli (1970) settles firmly in the cornea without the above risks, because the autogenous transplanted bone unites well with the grafted labial mucosa. 5 years of investigation have confirmed that glass ceramic Ceravital unites firmly with bones (Blencke et al. 1973, Strunz et al. 1977c, Bunte et al. 1977). For the osteo-keramo-keratoprosthesis Ceravital is used the same location as Dentin for the osteo-odonto-keratoprosthesis. The new surgical method has the advantage that 1. toothless patients can be operated, 2. the anterior chamber cannot flatten because the ceramic disk has the same shape as the corneal surface, and 3. broader optical cylinders can be used, by which a widening of the visual field is achieved.
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A simple new method is described for the histological evaluation of bones containing alloplastic implants of ceramic and/or metallic materials. The undecalcified bone is embedded in acrylic resin and sectioned at 50-200 micrometer using a sawing microtome. One surface of the preparation is stained up to 10 micrometer deep by floating the preparation on Giemsa stain. Other staining procedures are possible. Microscopic detail is satisfactory for histological and morphometric evaluation.
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The use of alloplastic material in the reconstruction of the defective or atrophic mandible appears obvious as the difficulties and risks of bone or cartilage transplants are well known. It appears that all the materials used up to now were demarcated by the bone as foreign bodies so that one could only observe strong union without a connective tissue line of separation with glass ceramics. In experimental operations in the pig, box shaped osteotomies were cut into the lower jaw and glass ceramic bodies were fixed into the clefts. Clinical and histological examinations proved the bone acceptance. It appears that these bio-active glass ceramics are particularly suited as bone replacement.
Oxalosis, a rare metabolic disorder, leads to excessive formation of oxalate and deposition of calcium oxalate crystals in the tissue. This leads to renal insufficiency with resulting secondary hyperparathyroidism and myelofibrosis. In a 27 year old female patient, extensive destruction of the maxilla, mandible and teeth was observed which has not yet been described and which led to the loss of all teeth.
After earlier experiments showed that bone became adherent to glass ceramic, the maximum mechanical stress on the bone-ceramic interface, as compared with polymethylmethacrylate (PMMA) and aluminium oxide ceramic, was investigated for shearing force and tension. Whereas the PMMA and aluminium oxide ceramic test objects which had been inclosed in the connective tissue were very easily pushed out without measurable pressure, the average fracture load for 15 smooth glass ceramic objects was 466 p/mm2 in the pushed out test and 167 p/mm2 in the tension test.
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In the histological preparation for surface layer staining, saw cuts 100-300 micrometer thick of undecalcified bone or tooth are made with or without alloplastic implantation material. Only one side of the cut is stained for 4 hours. During this time the stain penetrates about 15 micrometer into the preparation. Deeper-lying cells and structures remain unstained and appear merely as shadows that are not troublesome. The time-consuming process of making thin sections is dispensed with and variously stained serial sections are possible.
Six cases of benign primary epididymal tumor have been investigated in our patients. The tumor size fluctuated between 3 and 35 mm in diameter. Frequency, histology and medical development are described. The majority of epididymal tumors (53%) is comprised of so-called adenomatoid tumors of benign nature and their histogenesis is being discussed. The difficulties of differential diagnosis are pointed out. Since malignity exists in 26% of the cases, the surgical exposure and diagnosis by frozen section is being postulated, when suspicion of epididymal tumor becomes evident.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.