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Biomedical subjects

W Remagen

Publications and source records attributed to W Remagen.

At least 19 recordsLinked to original sources
PubMed1991

[Is it possible to differentiate between odontoameloblastoma and fibro-odontoma? Critical position on basis of 18 cases in DOSAK list].

An attempt was made to differentiate between odontoameloblastoma and ameloblastic fibro-odontoma by means of histological criteria based on 29 cases referred to the DOSAK-bone tumor register. After critical revision 18 appropriate cases have been selected for evaluation. We divided them into 4 odonto-ameloblastomas and 14 ameloblastic fibro-odontomas in accordance with the WHO classification. With respect to localisation, clinical symptoms, radiography, frequency of recurrencies and age no major difference was found between the two "entities". In our sample a decisive histological differentiation was not possible. This supports our hypothesis that there is only one entity.

Ameloblastoma↗
PubMed1990

[Pathological anatomy of femur head necrosis].

Aseptic necrosis of the femoral head appears to have a number of etiological factors. The last steps of the pathogenetic course of events, however, is unclear. Histologically, small foci of marrow necrosis form repeatedly, particularly in the upper and medial zone of charge, and then fuse secondarily to larger areas. Secondary reparation events with ingrowth of sprouts of granulation tissue and neoformation of bone predominantly in connection with necrotic trabeculi are followed by renewed waves of necrosis, resulting in a most variegated picture in which the different phases can no longer be clearly differentiated. After the articular cartilage has been sequestrated and torn away, the uncovered spongious bone is exposed to the transforming influence of direct charge, with subsequent secondary osteoarthrosis. From the histological picture follows the modern conception of its pathogenesis: an intraosseous increase in pressure primarily infringes on the venous outflow and secondarily on the arterial inflow. These cyclic circulatory disturbances provoke the focal appearance of necrosis. As a result of this, "core decompression" follows as a therapeutic intervention that is successful in many cases.

Bone Marrow↗
PubMed1988

[Six generalized and local osteopathies].

The remodeling of bone continues throughout life. It takes place in circumscribed areas called BMU (bone multicellular units), which during the remodeling process becomes BRU (bone remodeling units). The time span of the total remodeling process, the number of BRU and the distance in time between the appearance of these BRU in a given localization are responsible for the maintenance, or the increase or decrease, of bone substance, in particular of the trabecular bone. In bone atrophy, or osteopenia, and its clinical manifestation as osteoporosis there is decoupling of the remodeling process, with diminished bone formation which ultimately leads to perforations of the bone plates in the spongious bone. In Paget's disease of bone precipitate remodeling of bone causes the characteristic deformations. Recently, virus-RNA sequences have been shown in the bone cells, which is circumstantial evidence for a slow virus infection. Hyperphosphatasia is characterized by the same morphological alterations and discussion is currently in progress as to whether it is a congenital, or juvenile, form of Paget's disease. In osteogenesis imperfecta four different types are now distinguished; children affected by the most frequent type survive into adult life. In this condition, increased bone remodeling with insufficient bone formation is observed. In contrast, osteopetrosis, or marble bone disease, is due to an osteoclastic insufficiency and thus inadequate bone resorption. In this osteopathy a decoupling of the remodeling process has to be assumed: it is thought that other, still unknown, factors maintain regular bone formation although there is little or no bone resorption. The osteoclastic insufficiency has now been proven.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

[Histology of the implant-bone interface in cemented and uncemented endoprostheses].

The introduction of bone cement into endoprosthetic surgery was a significant step forward from the 'pre-cement' era. Nonetheless, its disadvantages soon stimulated the search for better means of anchoring implants without cement. Interest focuses on the so-called interface zone, which is the area between bone and foreign body. On the basis of light-microscopical findings our understanding of the biological and biomechanical interactions has influenced the principles of prosthetic design and the implant materials selected for use. The present article gives a synopsis of the histomorphology of the interface, with special reference to stability, tissue reactions, wear products, and implant fixation at bone surfaces (concerning bony ingrowth, osseointegration, and bonding). In all, 127 histological specimens of total hip and knee revisions were reviewed, in addition to a total of 24 non-cemented polyethylene cups retrieved at autopsy.

Bone Cements↗
PubMed1987

[Metastatic skipping in the bone marrow (skip metastases) in osteosarcoma. Frequency and clinical implications?].

The existence of skip metastases in osteosarcoma, a particular type of spread of this tumor, has been questioned. We have reviewed 229 cases of osteosarcomas and found two instances of skip metastases. In both the histological appearance of the metastatic forms and the primary tumor were identical. Our experience suggests that skip metastases are less frequent than originally proposed by Enneking and we discuss the possible clinical implications of our findings.

Adolescent↗
PubMed1986

Contiguous development of idiopathic osteonecrosis and osteoarthrosis in ischemia of a femoral head (radiological and morphological study).

In a 67 year-old man, an aseptic necrosis of the right hip joint developed side by side with an early oteoarthrosis characterized by an extensive narrowing of the upper interlinear space. The histological study revealed a diffuse ischemia which had evolved differently in the various regions of the femoral head. A well-limited necrosis appeared in a part of the weight-bearing zone, and osteoarthrosis developed in another one. In contrast with classical osteoarthrosis secondary to malformation, the osteoarthrotic lesions of the weight-bearing zone were caused by the ischemic angio-fibrosis of the bone marrow. At the beginning there was a resorption by the subjacent fibro-vascular tissue of the end-plate and of the deep layer of the cartilage. The osteosclerosis of this zone, in particular the eburnated plate, was formed mostly of fibre bone which rapidly became necrotic. Outside the weight-bearing zone, the subchondral angio-fibrosis and the non-inflammatory vascular pannus modified the articular surface.

Aged↗
PubMed1986

Morphometry of bone. Are parameters from the iliac crest reliable indicators of renal-insufficiency osteopathy?

Bone samples from 25 autopsy cases with chronic renal insufficiency were analyzed stereologically. The findings in the iliac crest were found to be representative of those of the rib, femur condyle and lumbar vertebra for the following stereologic parameters: volume of osteoid seems related to total bone volume [VV(OID/BONE)], surface of osteoid seams related to total bone volume [SV(OID/BONE)] and surface of osteoid seams in relation to trabecular surface [SS(OID/TRAB)]. In addition, the value of various stereologic parameters for the classification of osteopathies was checked.

Aged↗
PubMed1985

Extremity bone tumors: evaluation by P-31 MR spectroscopy.

High-resolution P-31 MR spectra were obtained in four patients with bone tumors of their distal extremities. In one case the tumor, a Ewing sarcoma of the tibia, was investigated during clinical remission after radiation therapy and chemotherapy. The other three cases - one low-grade chondrosarcoma of the tibial head, one malignant fibrous histiocytoma of the tibia, and one chondroblastoma of the medial femoral condyle - showed clinically active tumor growth, with corresponding increased metabolism as demonstrated by bone scintigraphy. The spectra of the three active tumors indicated a comparably high adenosine triphosphate content, similar to previously published spectra from animal tumors or human tumors implanted into animals. There were also high resonances of inorganic phosphate and low resonances of phosphocreatine; there were definite peaks in the phosphodiester and phosphomonoester regions, indicating the existence of these metabolites in the tumors. Slight but definite changes in the metabolite content were observed in one tumor after chemotherapy. The spectra of the unaffected leg did not show any well-resolved P-31 signals, which is typical for healthy bone. These are the first P-31 MR spectra of human bone tumors measured in patients to our knowledge.

Adolescent↗
PubMed1985

High-dose ifosfamide in advanced osteosarcoma.

In a prospective study, 18 evaluable patients with recurrent osteosarcoma were treated with ifosfamide, 1.8 g/m2 daily for 5 consecutive days. Courses were repeated every 4 weeks. Additional mesna (2-mercaptoethane sulfonate) was given to prevent urotoxicity. All patients had measurable lung deposits and all but one had been pretreated with various cytotoxic agents. Six patients (33%) showed therapeutic response, two complete and four partial, with a median duration of 5.5 months (range, 3-47+). Toxicity included myelosuppression, alopecia, nausea, and vomiting. No severe urotoxicity or central nervous system toxicity was observed. Thus, high-dose ifosfamide in combination with mesna seems to be a safe and effective agent for the chemotherapy of osteosarcoma.

Alopecia↗