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Biomedical subjects

G Prodi

Publications and source records attributed to G Prodi.

At least 55 records · Page 3Linked to original sources
PubMed1981

Induction of diphtheria toxin-resistant mutants in human cells by ultraviolet light.

Stable spontaneous mutants resistant to the protein synthesis inhibitor diphtheria toxin (DT) have been selected in human cell line EUE at a very low frequency (less than 8 x 10(-6)). U.v.-induced mutation has been quantitatively measured: treatment of cells with u.v. light increased the frequencies of diphtheria toxin resistant (DTr) mutants up to 1000-fold. The maximum recovery of DTr mutants was observed after a short expression period, for all u.v. doses tested, and was followed by a decrease in mutation frequency on subsequent passages.

Cell Line↗
PubMed1980

Multiple steroid hormone receptors in normal and abnormal human endometrium.

The cytoplasmic concentrations of ER, AR, PR, and GR were determined in 124 specimens of normal and abnormal endometrium and other uterine human tissues by the DCC technique. In the endometrial carcinoma group, we observed that pretreatment with MAP leads to low cellularity, higher amount of AR, lower amounts of detectable ER, GR, and PR: the last receptor was almost always absent. A positive correlation between ER presence and tumor grade of differentiation was found in endometrial tumors from hormone-untreated patients. With the value of 142 fmol/mg DNA as the cut off point between high and low binding capacity, the frequency of the single receptors within the hormone-untreated cancer group ranged from 61% to 88%; ER and PR were simultaneously present in 55% of cases (they are tightly correlated in the different biopsies with respect to frequency and amount); ER-AR-PR were present in 45% and all the four receptors in 40% of cases. Slightly higher values were found in normal endometrium collected from hormone-untreated patients.

Endometrium↗
PubMed1980

Effect of pesticides on scheduled and unscheduled DNA synthesis of rat thymocytes and human lymphocytes.

The action of seventeen pesticides (insecticides, fungicides and herbicides) has been studied with short-term in vitro system using rat thymocytes and/or human lymphocytes. The parameters studied were: a)the action of chemicals tested in scalar doses on DNA synthesis of rat thymocytes; b)damage exerted by pesticides on human lymphocyte DNA measured as unscheduled DNA sythesis; c)the interference of chemicals tested with human lymphocyte repair capability after damage exerted on cells by ultraviolet rays. The results obtained suggest that some of tested pesticides don't induce damages to human lymphocyte DNA, some others elicit low DNA repair if compared to the repair following a standard ultraviolet irradiation and some of them (6/17) exert a marked inhibition of cell repair processes after ultraviolet irradiation. Data are discussed on the basis of a possible role played by these substances as carcinogenic agents in the environment.

Animals↗
PubMed1980

Polycyclic hydrocarbons induction of diphtheria toxin-resistant mutants in human cells.

Stable spontaneous mutants resistant to diphtheria toxin are present in the human cell line (EUE) at a frequency of 0-8 x 10(-6). Mutation increases by a number of polycyclic hydrocarbons have been used as an estimate of their carcinogenic potency. Eight polycyclic hydrocarbons of decreasing carcinogenic potency were assayed: 7,12-dimethylbenz[a]anthracene, 3-methylcholanthrene, benzo[a]pyrene, benz[a]anthracene, dibenz[a,c]anthracene, dibenz[a,h]anthracene, chrysene, anthracene, and a well known mutagenic substance, ethyl methanesulfonate. In our system, which does not require an exogenous source for metabolic activation, the most potent hydrocarbons, 7,12-dimethylbenz[a]anthracene, 3-methylcholanthrene and benzo[a]pyrene revealed a strong mutagenic effect, whereas three non-carcinogenic hydrocarbons, anthracene, benz[a]anthracene and chrysene were not mutagenic. Our results indicate that there is a relationship between mutagenesis and carcinogenic potency for the tested polycyclic hydrocarbons. The maximum recovery of diphtheria toxin mutants was observed after an expression time of three weeks, corresponding to 10 cell generations.

Biotransformation↗
PubMed1979

17 beta-estradiol, 5 alpha-dihydrotestosterone, progesterone and cortisol receptors in normal and neoplastic human endometrium.

Using the value of 0.24 fmoles/microgram DNA as breaking point between high and low binding capacities, we quantified receptors for 17 beta-estradiol (ER), 5 alpha-dihydrotestosterone (DHTR), progesterone (PR) and cortisol (CR) in normal and neoplastic human uterine tissues. Concerning receptors occurrence, significant relationships were observed between ER and PR, ER and DHTR, and DHTR and PR. A direct correlation between the presence of ER and tumor grading was found: PR was less frequent in grade II and absent in grade III endometrial carcinoma, however this was not a significant correlation. In endometrial carcinoma at least 1 of the receptors was detected in 67-91% of the cases, 3 receptors (ER, DHTR, PR) in 56%, and all 4 receptors in 45%. The simultaneous detection of multiple receptors could play an important role in determining hormone response.

Aged↗
PubMed1978

In vivo DNA repair after N-methyl-N-nitrosourea administration to rats of different ages.

DNA repair time-course was studied after injury by N-methyl-N-nitrosourea (MNU) in rat liver cells of animals of different ages and in fetuses using hydroxyurea (HU) as inhibitor of scheduled DNA synthesis. DNA repair was a rapid phenomenon, more so in young adults than in newborns, and was not detectable in fetuses. A correlation seems to exist among organ sensitivity to carcinogen, age of animal and DNA repair.

Age Factors↗
PubMed1978

In vivo reaction of dimethylnitrosamine with nucleic acids.

7-Methylguanine is the main compound resulting from in vivo interaction between dimethylnitrosamine (DMNA) and nucleic acids, detected after strong acid hydrolysis. However, enzymic and alkaline hydrolysis of nucleic acids leads to quantitative liberation of methylamine. Methylamine isolated from liver nucleic acids of 15N-DMNA-treated rats has molecular weight of 31, thus demonstrating that DMNA-nitrogen is not involved in the binding.

Animals↗
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↗
PubMed1977

Cytoplasmic receptors for 17 beta-estradiol, 5 alpha-dihydrotestosterone and progesterone in normal and abnormal human uterine tissues.

Determinations of specific cytoplasmic receptors for 17 beta-estradiol (E), 5 alpha-dihydrotestosterone (DHT) and progesterone (P) in normal and abnormal endometrium are reported. The standardization of methodology with particular emphasis on specificity trials is outlined. Receptors were present in all but one case, a moderately differentiated endometrial adenocarcinoma. Generally speaking, steroid and peptide hormone plasma content in patients with malignant conditions were at the lower limit values of normal, except for follicle-stimulating hormone which had values significantly higher than normal. The question of E competition with DHT in binding DHT-receptor and the therapeutic implications of P-receptor estimation are discussed.

Adult↗