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Biomedical subjects

R Schmidseder

Publications and source records attributed to R Schmidseder.

At least 19 recordsLinked to original sources
PubMed1988

The adenoid cystic carcinoma. Special aspects of its growth and therapy.

In spite of its rare incidence the adenoid cystic carcinoma must be treated with respect because of its hidden malignant character. In 5 out of 21 patients recurrences occurred much longer than 5 years after the first operation. The extension of this tumour along branches of the trigeminal nerve could be well demonstrated in 7 of our patients where we were able to produce histological proof or radiographic evidence. The theory of tumour growth along the "tissue of least resistance" is illustrated by a special case report. As for the therapy, ultra-radical surgery has proved to be the most effective so far, whereas radio- or chemotherapy were only useful as palliative measures.

Adult↗
PubMed1981

Inhibition of DNA synthesis in permeabilized mouse P815 mast cells by arabinofuranosyladenine 5'-triphosphate.

P815 mast cells (mouse leukemic cells) have been successfully permeabilized to 9-beta-arabinofuranosyladenine 5'-triphosphate (araATP) using lysolecithin. The permeabilized cells remained viable according to the following criteria: (a) exclusion of trypan blue after replacing the lysolecithin with culture medium; (b) cell growth rate identical to control cultures, and (c) intact DNA-synthesizing complex in permeable cells. It was shown that permeabilized cells incorporate [3H]thymidine and [3H]deoxyadenosine-triphosphate (dATP) into DNA when the suspension is supplied with the appropriate substrates and cofactors. Permeable cells break down araATP to 9-beta-D-arabinofuranosyladenine 5'-diphosphate only slightly after incubation for 60 min; no further dephosphorylation to 9-beta-D-arabinofuranosyladenine 5'-monophosphate or 9-beta-D-arabinofuranosyladenine occurs. In kinetic experiments it was shown that the DNA-replicating complex of permeabilized cells is competitively inhibited by araATP with respect to dATP; Ki(araATP) was determined to be 0.6 microM and the Km(dATP), 0.9 microM.

Animals↗
PubMed1979

Additive effects of bleomycin and neocarzinostatin on degradation of DNA, inhibition of DNA polymerase beta, and cell growth.

The interactions of the two antitumor protein antibiotics, neocarzinostatin (NCS) and bleomycin (BLM), were studied on subcellular and cellular levels. BLM and NCS were found to remove thymine from double-stranded DNA. Combination experiments using BLM and NCS together in an assay with isolated DNA revealed an additive effect in splitting. Under limiting concentration conditions, BLM and NCS induce alkali-labile sites in DNA without a subsequent cleavage of the chain. After transfer of BLM- or NCS-treated DNA into an alkaline solution, strand scissions occur. Combination of BLM and NCS results in an additive DNA-cleaving effect, which indicates that the splitting reactions initiated by BLM or NCS are not influenced if the two antibiotics are applied in combination. The DNA polymerase beta is inhibited by BLM (at higher concentrations) and by NCS in a competitive way with respect to DNA. The inhibition constant of BLM and NCS in a combination experiment was found to be the result of the sum of the inhibition constants of BLM and NCS. Using L5178Y mouse lymphoma cells, it was found that cells incubated with both BLM and NCS show "unbalanced growth." The dose-response curves from BLM and NCS have identical slopes; they are characteristic for compounds which selectively inhibit DNA synthesis. By use of isobolograms, it could also be clearly shown that BLM and NCS interact additively.

Animals↗
PubMed1978

[The problem of the perioperative chemotherapy of the squamous epithelial carcinoma of the mouth].

In perioperative chemotherapy the question arises if, and to what extent, irritations of the wound-healing process are to be expected, especially after plastic surgery. Our research on wound-healing irritations under bleomycin therapy has been conducted in animal experiments and has resulted in definite recommendations for perioperative management. Taking UMEZAWA's experimental work as a basis, it can be assumed that the bleomycin-inactivating enzyme activity in squamous-cell carcinoma is in direct quantitative proportion to the bleomycin effect on these tumors. In clinical and experimental studies the bleomycin-inactivating enzyme activities of different squamous-cell carcinomas of the oral cavity have been tested. A lower enzyme activity - and a good clinical effect - has been found in highly differentiated carcinomas than in less differentiated and anaplastic carcinomas, with a less good effect. Reports in the literature on vascular support in carcinomas of the oral cavity prompted us to conduct microangiographic studies. Diminished vascularization with avascular regions of different size was found in most of the cases. Differentiated, medullar carcinomas showed a worse supply of blood vessels than undifferentiated and infiltrating carcinomas. The special morphological structures and functional factors of the tumor blood supply of the oral squamous-cell carcinoma are discussed in regard to their relevance for chemotherapy.

Bleomycin↗
PubMed1978

Diagnostic and therapeutic problems of myxomas (myxofibromas) of the jaws.

During the period from 1969 to 1977 11 cases of myxoma or myxofibroma in the jaw region have been treated at the Maxillofacial Surgery Clinic of the University of Mainz. Various kinds of diagnostic problems are discussed. We observed, inter alia, rapid tumour growth and a imitative dynamics in the radiographs, giving rise to a suspicion of malignancy in some cases. The locally infiltrative type of growth of myxomas must be taken into account during therapy, since insufficiently radical management is liable to be followed by a recurrence.

Adult↗
PubMed1978

[Effect of weather on odontogenic abscesses].

An increased frequency of odontogenous abcesses was observed on certain days in the course of routine clinical practice. We therefore investigated the possibility of a statistically significant weather-related odontogenous soft-tissue purulence originating from chronic apical periodontitis. Medical reports of patients treated between 1970 and 1977 were used. Our study indicated that the frequency of odontogenous abcesses was significantly higher with cyclonic weather conditions, i.e., weather with low barometric pressure.

Atmospheric Pressure↗
PubMed1977

Bleomycin-sensitivity test: application for human squamous cell carcinoma.

Bleomycin (BLM)-inactivating enzyme activity, which is probably a parameter for the efficacy of this antibiotic in cancer therapy, was determined in biopsies from human carcinomas in the head and neck region. Twenty-three cases were studied. It was found that highly differentiated as well as moderately differentiated squamous cell carcinomas had low extractable activities of this enzyme, comparably to those found in normal skin tissue. Slightly differentiated as well as undifferentiated carcinomas (only one case) had increased enzyme activity. Parallel experiments estimating the total extractable thiol content in the biopsies gave no obvious correlation. The results are discussed in the light of the reported BLM efficacy in the treatment of differently differentiated squamous cell carcinomas.

Bleomycin↗
PubMed1977

Spread of epidermoid carcinoma of the lip along the inferior alveolar nerve.

Reported is a case of epidermoid carcinoma of the lower lip that spread along the inferior alveolar nerve to the cranium. Early clinical symptoms are correlated with radiographic and histopathologic findings, and attention is again called to the fact that carcinomas of the head and neck may occasionally spread along nerve pathways.

Carcinoma, Squamous Cell↗
PubMed1977

Nerve injury in fractures of the condylar neck.

Although fractures of the condylar neck belong to the most frequent injuries of the jaws, and various nerves are found in close proximity to the temporomandibular joints, only little mention is made in the literature of neurological complications arising from accidents. We have therefore carried out a prospective study on nerve injuries in 237 fractures of the articular process in the period 1971-1975. We found two cases of post-traumatic Frey's syndrome, whereby the syndrome developed from a post-traumatic auriculotemporal neuralgia. We also found loss of function of auriculotemporal buccal and facial nerves, and loss of taste sensation of the tongue in another case, caused by damage to the chorda tympani. This paper discusses the formal and causal origin of the individual damages, and suggests possibilities for their management.

Chorda Tympani Nerve↗