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Biomedical subjects

L De Carli

Publications and source records attributed to L De Carli.

At least 37 records · Page 2Linked to original sources
PubMed1988

Griseofulvin.

Griseofulvin (GF) is a mycotoxin produced by various species of Penicillium including P. griseofulvum Dierckx, P. janczewski (P. nigricans) and P. patulum. It is active against dermatophytic fungi of different species in the genera Microsporum, Trychophyton and Epidermophyton. Because of its capacity to concentrate in the keratinous layer of the epidermis and its relatively low toxicity in man, it has been extensively used in the therapy of dermatophytoses by oral administration. The biological activity of GF towards fungi is manifested as nuclear and mitotic abnormalities followed by distortions in the hyphal morphology. Mitotic segregation is also induced in fungi by GF treatment. In higher eukaryotes the cytostatic action of GF is essentially due to a mitotic arrest at late metaphase/early anaphase. The cytological effects observable both in vivo and in vitro on different plant and animal cell systems, include C-mitoses, multipolar mitoses and multinuclearity. Prolonged GF treatment in experimental animals provokes biochemical changes consisting mainly of disturbances of porphyrin metabolism, variation in the microsomal cytochrome levels and formation of Mallory bodies. In mice these alterations are followed by the development of multiple hepatomas. Evidence of tumor induction by GF has been obtained in mice and rats, but not in hamsters. GF may also act either as a promoting or a co-carcinogenic agent, depending on the circumstances of its administration. It has been found to increase the frequency of cell transformation induced by polyoma virus, but not to induce cell transformation per se. Induction of sperm abnormalities has been observed in GF-treated mice. The embryotoxic and teratogenic action of GF has been demonstrated in pregnant rats exposed during organogenesis. Genetic effects of GF have been investigated by the following tests: Salmonella/microsome mutagenicity assay, point mutations in mammalian and plant cells, DNA damage and repair, SCE, chromosome aberrations, micronuclei, dominant lethals, aneuploidy in lower and higher eukaryotes. A positive response has been obtained in the assays on numerical chromosome changes in all the systems analyzed; limited or inconclusive evidence has been obtained for SCE and structural chromosome changes. Doubled or highly polyploid sets can be detected in all types of cells during or immediately after GF treatment. A marked increase in chromosome number variation is observed at various times after withdrawal of the drug, with prevailing hyperdiploid and reduced sets in animal cells and plant cells respectively.(ABSTRACT TRUNCATED AT 400 WORDS)

Carcinogens↗
PubMed1987

Chromosomal aberrations induced in human cultured cells by liposome-encapsulated deoxyribonuclease I.

Experiments of incorporation of a nucleolytic enzyme into human cells cultured in vitro have been carried out with the aim of inducing structural chromosome variations. Human heteroploid cells, either as asynchronous populations or enriched in mitoses, and PHA-stimulated lymphocytes were used as recipients. We found that all these cells when exposed to pancreatic DNAase I encapsulated in liposomes, either of multilamellar (MLV) or of small unilamellar (SUV) type, show an incidence of chromosome damage higher than that induced by the enzyme free in the incubation buffer. Our results indicate that liposomes are suitable vehicles for the transfer of an exogenous nuclease into human cultured cells. The enzyme remains functionally active and interacts with nuclear DNA, giving rise to chromosome lesions.

Aneuploidy↗
PubMed1986

Studies on host-virus genome relationship in Epstein-Barr virus immortalized lymphoblastoid cell lines.

Five human lymphoblastoid cell lines immortalized in vitro with the B95-8 EBV strain, chosen to have a low number of copies of EBV genome, were examined to detect variations in electrophoretic mobility of viral restriction fragments and in the karyotype. Patterns of mobility detected with different viral probes are always the same as those obtained with fragments from purified virus-plasmidic DNA, with one exception. This "non-plasmidic" pattern occurs with a probe containing the termini of the linear virion DNA and consists in an increase of the molecular weight and in the appearance of more than one band. Cytogenetic studies carried on the same cell populations used as source of DNA, early after immortalization, showed a diploid modal chromosome number and no G banding rearrangements.

Cell Line↗
PubMed1983

A comparative cytogenetic study on cases of induced abortions in TCDD-exposed and nonexposed women.

In order to evaluate the cytogenetic findings previously obtained on induced abortions in women exposed to 2,3,7,8 tetrachlorodibenzo-p-Dioxim (TCDD) after the Seveso accident, chromosome analyses were carried out on a comparable control sample. The frequencies of aberrant cells, the relative proportions of individual types of chromosome aberration, the average number of lesions per damaged cell, and the frequencies of polyploids do not differ significantly in maternal blood and placenta in the two samples. A highly significant increase in the frequencies of aberrant cells and in the average number of aberrations per damaged cell was found in the fetal tissues in the group of exposed pregnancies. A noticeable feature of the data on the frequencies of cells with aberrations is the marked variability among individuals within tissues and within samples. On the basis of these results, the authors point to the need to continue cytogenetic investigations on interrupted pregnancies in TCDD-exposed and nonexposed women.

Abortion, Induced↗
PubMed1983

Double Y as an indicator in a test of mitotic nondisjunction in cultured human lymphocytes.

A cytological test for the detection of non-disjunction in human cultured lymphocytes has been developed. The Y chromosome was used as a marker, because this chromosome is easily identifiable in mitosis after staining with quinacrine dihydrochloride without karyotyping. Non-disjunction can be directly revealed by scoring mitoses with two Ys. The test was applied to agents known for their ability to induce numerical and/or structural changes in chromosomes, namely benomyl, colcemid, distamycin A, mitomycin C and X-rays. In treated lymphocytes, increased frequencies of YY mitoses were found, ranging from 2.5 X 10(-4) to 61.2 X 10(-4) (control value less than or equal to 1.1 X 10(-4). The results suggest that the detection of fluorescent Y chromosomes on metaphases is suitable for determining induced non-disjunction in human cultured cells.

Cells, Cultured↗
PubMed1983

Studies on transformation markers and tumorigenicity in segregant clones from a human hybrid line.

Thirty segregant clones were back-selected in 8AG or 5BUdR media from a non-tumorigenic human intraspecific hybrid line (HeLa TK- X fibroblasts HPRT-) displaying a high plasminogen activator (PA) level, a disorganized fibronectin (FN) matrix and anchorage-independence. These clones exhibited a widely modulated expression of the above markers concomitantly with different degrees of chromosome loss. Out of six representative segregant clones tested in nude mice, two were found to re-express tumorigenicity. No significant correlation was observed between PA or FN levels and anchorage-independence, as well as between these markers and tumorigenicity.

Animals↗
PubMed1982

Expression of transformation markers and suppression of tumorigenicity in human cell hybrids.

Somatic human cell hybrids produced by fusion of HeLa cells and diploid fibroblasts were analysed in a study designed to test the coordinate expression of transformation markers and tumorigenicity. The great majority of these hybrids displayed a finite lifespan in culture, but some of them inherited from the HeLa parent the capability to grow as permanent cell lines. Hybrids from both groups all had a plasminogen activator activity 20 to 100-fold higher and a cloning efficiency in semisolid medium 2 to 10-fold lower than the HeLa parent. Cell surface fibronectin was expressed at variable levels, albeit in a disorganized form. No correlation between the level of plasminogen activator or fibronectin content and cloning efficiency in agar was observed. Two hybrid lines, assayed for tumorigenicity in nude mice, did not produce tumors, even at inocula 20-fold greater than those at which the HeLa cells formed tumors.

Animals↗
PubMed1979

Chromosome lesions in amniotic fluid cell cultures.

The frequencies of chromosome lesions were determined on 3537 mitoses in samples of varying sizes from cultures of 25 amniotic fluid specimens taken from patients at cytogenetic risk. The average percentage values of aberrant cells, including and excluding gaps, were 12.5 and 4.9, respectively. The corresponding values for fibroblasts and peripheral blood lymphocytes from normal adult donors, calculated under the same laboratory conditions, were 5.0 (including gaps) and 2.4 (excluding gaps) and 2.4 (including gaps) and 1.0 (excluding gaps), respectively. The hypothesis of a correlation between the increased incidence of chromosome lesions and the occurrence of abnormal karyotypes in amniotic fluid cell cultures is discussed.

Amniotic Fluid↗
PubMed1979

Expression of thymidine kinase activity in hybrids between human leukemic cells and a TK-mouse cell line.

A series of actively proliferating clones have been isolated after PEG-induced fusion of a thymidine kinase deficient murine line and white blood cells from two leukemic patients. Their hybrid nature was proved both cytologically and biochemically. All the hybrids tested showed levels of TK activity significantly higher than the TK- mouse parental cell line and comparable to those exhibited by replicating TK+ cells.

Animals↗
PubMed1978

DNA repair in UV-irradiated heteroploid cells at different phases of the cell cycle.

The variation of DNA repair activity during the cell cycle was studied by analysing the UV-stimulated DNA synthesis in cells synchronized in mitosis. This activity was detected both by autoradiography and by directly measuring the incorporation of tritiated thymidine in cells irradiated and incubated in the presence of hydroxyurea. Cells in all phases were found to be able to perform repair. However the activity appeared to be considerably lower in mitotic cells than in cell in other phases. Increasing values of repair capacity were observed in G1 cells, in mixed G2, S and M cells and in asynchronous cells. The relationship between these findings and data on survival rates in the same synchronized cells is discussed.

Autoradiography↗