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Biomedical subjects

J Petres

Publications and source records attributed to J Petres.

At least 55 records · Page 3Linked to original sources
PubMed1976

[Recurrent skin tumors and their surgical management].

Recurrences of basal cell carcinomas and squamous cell carcinomas are possible in cases of radiation before surgical treatment. This inadequacy occurs in general, if the emphasis of the treatment was on the cosmetical point and therefore the necessary radical therapy had been neglected. Furthermore cicatrizing basal cell carcinomas are prone to recurrences, after only a macroscopical tumor extirpation had been carried out. In special cases of epidermal tumor recurrences our dermato-surgical proceedings are demonstrated. The repair of large skin defects, caused by surgical treatment, requires methods of plastic and reconstructive surgery. Should there be any doubt whether the therapy is radical enough, material for microscopical examination should be taken immediately.

Aged↗
PubMed1975

[Fumaric acid monoethylester: Effect on DNA-synthesis and preliminary findings in experimental studies in animals (author's transl)].

The incorporation of 14C-Thymidin into DNA of cultured human lymphocytes is depressed by added fumaric acid monoethylester (FSME) depending on the dosage of FSME. The decreased radioactivity in DNA as measured by scintillation counting is paralleled by a concomitant decrease in the labelling index in autoradiograms. Decreasing radioactivity is therefore due to a lower number of DNA synthesizing cells. No selective inhibition of proliferation during one of the cell cycle phases was observed. Especially a G2-block known from other cytostaties is absent. A mean dosis of 6.88 mg FSME per g body weight administered intraperitoneally is lethal to mice. The animal die from diffuse necroses of heart muscle cell. Alterations of other organs are less prominent. At lower doses of FSME the morphology of the organs investigated is altered to a smaller degree.

Animals↗
PubMed1975

Further in vitro studies on the biochemistry of the inhibition of nucleic acid and protein synthesis induced by arsenic.

Human lymphocytes, stimulated by PHA, and exposed to increasing Na2HAsO4 concentrations, show an identical incorporation rate for 14C thymidine and 14C-TTP into the DNA. 14C uridine is incorporated 3--4 per cent less at an As concentration of 1.0 mug/ml medium, above this however approximately 15 per cent less into the RNA as compared to 14C-UTP. In free pyrimidine bases, the incorporation of labelled triphosphates into the DNA and RNA is significantly reduced above 1 mug and 10 mug Na2HAsO4. Corresponding to its approximately uniform distribution into DNA and RNA, the incorporation rate of 14C-ATP above 10 mug Na2HAsO4/ml culture medium lies between that of 14C-UTP and 14C-TTP. The incorporation of 14C alanine and 14C leucine into cellular protein is not reduced below 10 mug Na2HAsO4/ml. The incorporation rate is 41 per cent at a concentration of 100 mug Na2HAsO4/ml medium. Compared to 14C-UTP, 14C-ATP and 14C-TTP it is increased by the factor of 1.8; 2.5 and 6.8 respectively. The inhibition of enzymes of the dark repair mechanisms and the synthesis of biopolymers together with their altered sequence and the involvement of long-lived messenger RNA serve as an explanation of the observed alterations of the lymphocyte metabolism, caused by arsenic.

Adenosine Triphosphate↗
PubMed1975

Mycosis fungoides with marked brain involvement--a case report.

The clinical course of a patient with mycosis fungoides, which could be confirmed histologically in the premycotic stage, 2 years after the onset of the disease is reported. The disease led to death after a further 3 years, during which the infiltrative and tumorous stage had appeared. At autopsy, apart from the skin changes typical for mycosis fungoides, involvement of the pia mater, plexus chorioideus, cerebrum and cerebellum was established. This constituted the only manifestation of the disease in the internal organ systems. There were no detectable neurological defects.

Adolescent↗
PubMed1975

[The effect of fumaric acid monoethylester on the synthesis of nucleic acids and proteins of PHA-stimulated human lymphocytes (author's transl)].

Fumaric acid monoethylester (FAME) inhibits the incorporation of 14C-Thymidin, 14C-Uridin, 14C-Alanin and 14C-Leucin into acid-insoluble biopolymers of cultivated PHA-stimulated human lymphocytes. At high concentrations of FAME (500 mug/ml culture medium) the inhibition of nucleic acid synthesis is 6 times higher on the average than the inhibition of protein synthesis. However, the application of the cis-isomer, maleic acid monoethylester (MAME), results in an increase of the incorporation rate of the labelled precursors into the RNA and DNA. This is 3.5--9.3 times higher than after application of FAME. The results demonstrate the specific inhibition by FAME. The rate of labelling of nucleic acids is decreased above 10 mug FAME/ml culture medium and in the case of MAME above 50 mug/ml medium. As an explanation of the specific action of FAME its influence on the enzymes of the nucleic acid synthesis, the citric acid cycle or a faulty synthesis of enzymes are discussed.

Alanine↗
PubMed1975

[Effect of arsenic on the incorporation of 14C-thymidine into DNAP of phytohaemagglutinin-treated lymphocytes (author's transl)].

In lymphocyte cultures stimulated with PHA Na2HAsO4 is able, independent of the arsenic doses used (10 mug, 30 mug, 50 mug/ml culture medium), to increase the 14C-thymidine incorporation in acid precipitable biopolymers. The increase was 17 plus or minus 4% at 1 hr exposure to arsenic, compared with control cultures which were not exposed to arsenic. The administration of 30 mug and 50 mug Na2HAsO4/ml medium at incubation periods between 2 and 18 hrs resulted in a decrease in the radioactive incorporation rate into the DNA which was dependent on dose and time. Using 10 mug Na2HAsO4 per ml medium, the 1 hr stimulation is followed by an inhibition (up to approximately 35%, control equals 100%), which lasts for approximately 3 hrs. This is followed by an increase in the 14C-thymidine incorporation into the DNA for a further 2 hrs. The course of the inhibition curve with 10 mug Na2HAsO4 and with exposure times between 6 and 18 hrs the decreases again dependent on dose and time. As an explanation of the stimulation of the 14C-thymidine utilisation by arsenic, we suppose an increased repair activity. This may lead to a situation where (labelled) bases which are added outside the synthesis phase are incorporated into the DNA. The inhibition of 14C-thymidine incorporation which is dependent on dosage and time, with larger doses of arsenic can be explained by a prevailing influence of enzymes of the synthesis system (e.g. polymer arsenic), while the unusual course of the inhibition curve under the influence of 10 mug Na2HAsO4 shows that an activation and inhibition of enzyme systems (synthesis and repair) which is displaced in time is taking place. Apart from this, disturbances of regulation processes of the DNA replication and the initiation overlap can also be suspected as a cause of the phenomena observed.

Arsenates↗