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Biomedical subjects

K J Münzenberg

Publications and source records attributed to K J Münzenberg.

At least 19 recordsLinked to original sources
PubMed1990

Effects of propane-2, 2-diphosphonate (PDP) on matrix-induced ectopic bone formation in comparison to ethane-1-hydroxy-1, 1-diphosphonate (EHDP).

The most prominent effect of propane-2, 2-diphosphonate (PDP) and ethane-1-hydroxy-1, 1-diphosphonate (EHDP) on matrix-induced ectopic bone in the rat was a dose-dependent inhibition of osteogenesis in the early phases of development. The delay was seen as a consequence of osteoprogenitor cell inhibition. Additionally, later phases of bone maturation were disturbed by interference with the mineralization and remodeling processes. However, direct effects on the calcium phosphates of bone are only of minor additional value, which remains of lesser importance in comparison to the cellular impairment. After withdrawal of diphosphonates, the effects were nearly completely remitted. Neither PDP nor EHDP, even given in high doses, resulted in a lasting reduction in ectopic mass. The remission may be referred to the recovery of cell activities, whereas the mineral impregnation of osteoidosis was, if at all, of little importance. For treatment of ectopic osteogenesis PDP proved inefficient.

Animals↗
PubMed1990

Analogous effects of organic calcium antagonists and magnesium on the epiphyseal growth plate.

High doses of both calcium antagonists and magnesium lead to disorders in the early phase of calcification. Analogous to known mechanisms of calcification outside the bone, the calcium overload of cellular suborganelles, which may play a role in enchondral ossification, is assumed to be prevented or delayed by calcium antagonists and magnesium. In accordance with the relevant literature, which describes analogous cytoprotective effects of calcium antagonists and magnesium in association with extraskeletal calcification and ossification, the qualitative agreement of histologic findings in the epiphyseal growth plate suggests a homologous, primarily intracellular mechanism of action of both magnesium and organic calcium antagonists. This common mechanism of action of the two substances on the molar Mg-Ca quotient, with reference to intracellular calcium phosphate mineralization, is regarded as the cause of the analogous effects.

Animals↗
PubMed1989

[The effect of benzenecarboxylic acids--in particular mellitic acid--in in vitro biological system].

Influence of Benzenecarboxylic Acids, Particularly Mellitic Acid, on Biological in vitro Systems. In a first part of the present paper influences of mellitic acid and some other benzenecarboxylic acids on reduplication of Ehrlich ascites tumor cells cultured in vitro are reported. Mellitic acid in the concentration range between 1 and 5 mmol/l caused an increase, in concentrations of 10 mmol/l and above an inhibition of cell multiplication. Benzoic acid, phthalic acid, hemimellitic acid and pyromellitic acid showed in concentrations above 6 to 10 mmol/l inhibitory effects on cell multiplication. The second part reports studies on potential influences of mellitic acid on growth and mesenchymal metabolism of explanted murine fetal tibiae cultured in vitro for six days. Mellitic acid effected in concentrations between 0.5 and 15 mmol/l as compared with control cultures a concentration dependent inhibition of calcification and in concentrations above 2 mmol/l significant increases of the glycosaminoglycan content and growth of the explants, whereas DNA-, total protein- and hydroxyprolin content were not significantly influenced by concentrations up to 10 mmol/l.

Animals↗
PubMed1980

[Aneurysmatic osseous cyst with malignant course (author's transl)].

The article reports on a case of an aneurysmatic bone cyst which deteriorated into a malignant cyst four years after the first exposure to roentgen radiation, developing massive metastases in the lung after two further years. Almost all malignant courses of an aneurysmatic bone cyst which have been described in literature (a total of 12 cases so far) developed subsequent to x-ray treatment. The case reported here is unusual in so far as the malignant transformation took place after a short while only, whereas the total radiation dose was relatively low. The authors sound an urgent warning against x-ray treatment of aneurysmatic bone cysts.

Adolescent↗
PubMed1979

[Diagnosis and differential diagnosis of osteosarcoma (author's transl)].

A primary malignant bone disease can generally be suspected on the basis of x-ray findings and may be even highly probable if several signs of malignancy are seen on one and the same film. Such changes include bone lesions larger than 6 cm on the first film with blurred outlines, showing patterns of destruction resembling moth-eaten textiles, the covering periosteum revealing spicula or Codman's triangles. Rapidly growing tumours can break cortex components from the continuous layer and shift them outwards. Roentgenological case controls are useless and must be replaced by a sample excision, since x-ray malignancy signs have no absolute value as decisive criteria in view of the fact that they are seen, inter alia, also in osteomyelitis, myositis ossificans and callus formations.

Bone Neoplasms↗
PubMed1978

[Treatment of Sudeck's syndrome with calcitonin (author's transl)].

Ten patients with Sudeck's syndrome were treated with porcine calcitonin. If this hormone, which inhibits bone absorption, is given no later than the first or in the transition from first to second stage, the spontaneous burning pain and, after some weeks, the oedema and increased warmth disappear. Calcitonin is as effective as corticosteroids. But its range of application is wider, because it has fewer side effects and can be administered particularly where corticosteroids are contra-indicated. But it is ineffective in stage III. Synthetic salmon calcitonin is now available, and more effective than porcine, lasts longer and is the drug of choice in Sudeck's syndrome.

Aged↗
PubMed1978

[On the effect of methane-bis--phosphonate in vivo (author's transl)].

After s.c. injections of methane-bis-phosphonate into rabbits, calcified incrustations developed around the injection sites. These incrustations were less radiolucent than the surrounding tissues. They appeared to have a good crystalline apatite structure in X-ray diffraction. The findings agree with our previous in vitro studies but disagree with the findings in the literature that ethane-1-hydroxy-1,1-diphosphonate (EHDP) and dichloromethyle-nediphosphonate (Cl2MDP) inhibit crystal growth of apatite already formed.

Animals↗
PubMed1977

[Therapeutic measures in osteogenesis imperfecta (author's transl)].

The treatment of osteogenesis imperfecta with magnesium is theoreticaly sound, but usually works in a few individuals. There are greater expectations with calcitonin, which reduces the overall osteolysis. The treatment of fractures should, whenever possible, be concervative. Internal fixation by plates is not indicated, because the plate should span from metaphysis to metyphysis, which leads to a softeming of the underlying cortex. Because of the weak bone, srews do not hold well. For operative treatment of the lower limb, the Küntscher nail is the fixation of choice, as well as for treatment of deformity by multiple fragmentation. Rapidly progressive scoliosis should be treated operatively from 9 years of age on.

Age Factors↗
PubMed1977

[Pathophysiology and metabolism in osteogenesis imperfecta (author's transl)].

The tissue changes in osteogenesis imperfecta apparently lie in the collagen and in the glycosaminoglycans. The collagen shows structural development disturbance and incomplete calcification. The tissue glycosaminoglycans are increased. The basis probably lies in a disturbed ATP metabolism (Solomons and Millar, 1973). An increased pyrophosphate concentration explains the decreased calcification and the structural changes. The increased osteolysis could be explained by increased quantities of cAMP.

Bone Resorption↗
PubMed1977

[On the growth characteristics of human osseous sarcoma metastases: mathematical calculations and clinical consequences (author's transl)].

Metastases of osteosarcomas do not grow according to a simple exponential function, but rather according to a type of Gompertz' function where flattening with a tendency toward plateau formation sets in after a certain time. This deviation from an exponential growth type corresponds to a substantial increase in the initial tumor size--doubling time. The metastasis doubles in the period after its transfer faster than when it first becomes visible in an x-ray. Another important conclusion resulting from the use of the Gompertz model is the assumption of a tumor-specific maximum volume which cannot be exceeded over a period of infinite growth. For lung metastases of osteosarcoma this volume amounts to approximately 120 cm3. The critical volume which kills the host is, at 70 to 80 cm3, relatively close to this theoretical growth limit (only approximately one cell division below this limit). If a metastasis develops from a single cell, the number of divisions up to this point is approximately 46. Of these, 38 lie within the growth zone which is not visible via x-ray. Since cell-cycle specific agents (for example Vincristin and Methotrexate) have the greatest effect against rapidly proliferating tumors, these drugs (for example alkylantic drugs) are especially effective in the case of slowly proliferating neoplasms. Therefore, use of these drugs should be favored when the metastasis is visible in the x-ray. Since occasionally, particular when the primary tumor is still relatively small, metastasization may not necessarily have already taken place, radical operation of the primary tumor should be carried out as soon as possible. A preliminary irradiation of the primary tumor cannot prevent metastasization with certainty. Therefore delayed amputation should be avoided.

Bone Neoplasms↗