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Biomedical subjects

P Rocchi

Publications and source records attributed to P Rocchi.

At least 19 recordsLinked to original sources
PubMed1992

Induction of myogenic differentiation in human rhabdomyosarcoma cells by ionising radiation, N,N-dimethylformamide and their combination.

Differentiation-inducing ability of gamma-radiation, N,N-dimethylformamide and their combination has been tested on human rhabdomyosarcoma RMZ-RC2 clone cells. Ionising radiation at 2-5 Gy doses induced a more differentiated morphology, with the appearance of an increased proportion of multinuclear myotube-like cells, and a significant increase in myosin-positive and multinuclear cells. Radiation appeared to act by inducing de novo differentiated elements. N,N-dimethylformamide was able to induce an increased myosin expression, but did not affect multinuclear cell proportion. The combined treatment (ionising radiation and N,N-dimethylformamide) resulted in an additive increase in the proportion of myosin-positive cells, approaching 25-35%, but de novo differentiated elements were not increased above the levels obtained with irradiation alone.

Cell Differentiation↗
PubMed1990

Establishment and characterization of a primitive neuroectodermal tumor of bone continuous cell line (LAP-35).

A continuous tumor cell line (LAP-35) was established from a primitive neuroectodermal tumor of bone from the right tibia of a 12-year-old female. The neural character of the cell line was documented by the spontaneous growth of neurites and by the presence of several neural markers, including neuron-specific enolase (NSE), S-100 protein, neurofilaments, chromogranin A, synaptophysin and positivity to monoclonal antibodies UJ127.11, UJ13A, UJ181.4. Cell-sorter analysis showed a high expression of nerve growth factor receptor (NGFr) and major histocompatibility complex class I-related molecules. A unique cytogenetic profile was observed, including a reciprocal chromosomal translocation (rct) 11:22 (q24;q12), typically associated with Ewing's sarcoma and neuroepithelioma, and deletion of the short arm of chromosome 1 (lp-), otherwise a feature of neuroblastoma. N-myc proto-oncogene was neither amplified nor expressed, whereas the expression of c-myc was documented by northern blot analysis. These features distinguish this new cell line from previously reported neuroectodermal cell lines, identifying LAP-35 as a unique model of a group of neural bone tumors that share characteristics of neuroblastoma as well as neuroepithelioma.

Animals↗
PubMed1986

Effect of antioxidants on mutagenesis induced by DMBA in human cells.

The effect of vitamin A palmitate (VAP), vitamin A acetate (VAA), 2,3-tert-butyl-4-hydroxyanisole, and 2,6-di-tert-butyl-p-cresol (BHT) on mutagenesis induced by 7,12-dime-thylbenz[a]anthracene (DMBA) was examined in a human epithelial-like cell line. Cultures were exposed to DMBA with or without the antioxidant compound, and mutation frequencies were determined by selection against diphtheria toxin. A clear inhibition of mutagenesis was observed particularly with VAA and BHT.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1977

Compared effects of N-hydroxyurethan, urethan and hydroxyurea on DNA synthesis. In vivo and in vitro studies.

The effect of N-hydroxyurethan (HUR) on DNA synthesis has been tested both in vivo on various tissues and in vitro on concanavalin A (ConA)-stimulated rat thymocytes and compared with the action of urethan and hydroxyurea. HUR suppresses scheduled DNA synthesis, except that of non-stimulated spleen cells in vitro. The inhibition is efficient and rapid and takes place immediately if the drug is administered at the peak of the S-phase. UR inhibits DNA synthesis in vitro only at much higher doses and with different time course. It is effective or slightly effective if it is administered at the peak of the S-phase. A conversion of urethan into HUR the latter depressing DNA synthesis could partly explain the differences observed. No toxicity was found after treatment with drugs at the concentration employed. Finally, the relationships between drug doses and cell responses have been particularly observed in vivo.

Animals↗
PubMed1975

Effect of urethan on the synthesis of nucleic acids in thymus, spleen, and bone marrow.

Urethan, in a single dose of 1 mg/g body weight, exerts a strong inhibitory effect on DNA synthesis in lymphoid organs and bone marrow of rat. The inhibition observed in spleen and thymus is longer lasting than that exerted on bone marrow or regenerating liver, demonstrating a marked sensitivity of lymphoid cells to the drug. This effect can explain the rapid reduction of weight and cell number in thymus and spleen under urethan treatment, in absence of any lymphocytolytic action. The different effect of urethan on the different subpopulations of lymphoid cells therefore appears to be due to their kinetics rather than to a specific sensitivity of some of them.

Animals↗
PubMed1975

Non-enzymatic and microsome-dependent binding of poly-cyclic hydrocarbons to DNA and polynucleotides.

The binding of tritium-labeled 7,12-dimethylbenz[a]anthracene (DMBA), benzo[a]pyrene (BP) and 3-methylcholanthrene (MCA) to DNA or polynucleotides in vitro was re-examined both in the presence and in the absence of rat liver or human placental microsomes. A high level of non-enzymatic binding was evident when thymus DNA was used as acceptor. This non-enzymatic binding made it difficult to determine the effect of microsomes, except in the case of BP when induced rat microsomes were used. Better results were obtained using polynucleotides: a definite microsome-dependent binding occurred between all the polynucleotides and all the hydrocarbons tested. No clear evidence of binding catalysed by microsomes from human placenta was found except in polynucleotide-BP interactions: further studies are required to completely evaluate the ability of such nucleic acid-microsomal system for testing in vitro possible oncogenic substances in animals and humans.

9,10-Dimethyl-1,2-benzanthracene↗