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Biomedical subjects

G Turi

Publications and source records attributed to G Turi.

At least 19 recordsLinked to original sources
PubMed2004

Clostridial orthopedic infections: case reports and review of the literature.

Clostridia are anaerobic Gram-positive bacilli that can be isolated from the soil and the intestinal tract of humans. These microorganisms are recognized as the cause of devastating soft tissue infections, such as cellulitis, myositis, and gas gangrene. However, such bacteria may also be involved in various postoperative orthopedic infections, including prosthetic joint infection. We present three clinical cases of clostridial orthopedic infection and review the related medical literature.

Adult↗
PubMed1999

Gonadotropin-releasing hormone analogue conjugates with strong selective antitumor activity.

Conjugation of gonadotropin-releasing hormone (GnRH) analogues GnRH-III, MI-1544, and MI-1892 through lysyl side chains and a tetrapeptide spacer, Gly-Phe-Leu-Gly (X) to a copolymer, poly(N-vinylpyrrolidone-co-maleic acid) (P) caused increased antiproliferative activity toward MCF-7 and MDA-MB-231 breast, PC3 and LNCaP prostate, and Ishikawa endometrial cancer cell lines in culture and against tumor development by xenografts of the breast cancer cells in immunodeficient mice. MCF-7 cells treated with P-X-1544 and P-X-1892 displayed characteristic signs of apoptosis, including vacuoles in the cytoplasm, rounding up, apoptotic bodies, bleb formation, and DNA fragmentation. Conjugates, but not free peptides, inhibited cdc25 phosphatase and caused accumulation of Ishikawa and PC3 cells in the G2/M phase of the cell cycle after 24 h at lower doses and in the G1 and G2 phases after 48 h. Since P-X-peptides appear to be internalized, the increased cytotoxicity of the conjugates is attributed to protection of peptides from proteolysis, enhanced interaction of the peptides with the GnRH receptors, and/or internalization of P-X-peptide receptor complexes so that P can exert toxic effects inside, possibly by inhibiting enzymes involved in the cell cycle. The additional specificity of P-X-peptides compared with free peptides for direct antiproliferative effects on the cancer cells but not for interactions in the pituitary indicates the therapeutic potential of the conjugates.

Animals↗
PubMed1999

Effects of methylacetylenic putrescine, an ornithine decarboxylase inhibitor and potential novel anticancer agent, on human and mouse cancer cell lines.

Sensitivity of several human and mouse cancer cell lines to methylacetylenic putrescine (MAP) was evaluated using clonogenic, sulforhodamine B and cell counting assays. The effects of MAP on cell morphology, cell cycle phase distribution and changes in polyamine metabolism of xenografted MCF-7 and MDA-MB-231 human mammary tumor cells were also investigated. On the basis of IC50 values, BHT-101 human thyroid carcinoma cells were the most sensitive (9 micrograms/ml), followed by P388 mouse lymphoma (32 micrograms/ml), MCF-7 (48 micrograms/ml) and MDA-MB-231 (110 micrograms/ml) human breast carcinoma cell lines. MAP treatment led to accumulation of P388 cells in G1 phase. At higher doses, the cytoplasm of the cells became vacuolated followed by apoptosis. The foamy cytoplasm may suggest a rare type of cell death (Clarke III type) called non-apoptotic programmed cell death. MAP treatment resulted in a total inhibition of ornithine decarboxylase (ODC) activity with a concomitant decrease of intracellular polyamine (mostly putrescine and spermidine) content in the breast cancer cells, whilst the spermine concentration was shown to increase. MAP proved at least 10 times more potent than the formerly studied DL-alpha-difluoromethylornithine making it an attractive candidate for clinical testing.

Alkynes↗
PubMed1997

Synthesis of gonadotropin-releasing hormone III analogs. Structure-antitumor activity relationships.

Following the observation that the activity of gonadotropin-releasing hormone III (GnRH-III) in the suppression of growth of MDA-MB-231 and MCF-7 breast cancer cells surpasses that of GnRH and other analogs thereof, analogs of GnRH-III were synthesized to investigate the structural basis for the improved antitumor activity. Compounds synthesized include analogs with changes in the central sequence in which GnRH-III differs from GnRH and in the C- and N-terminal regions. The results indicate that a salt bridge between Asp6 and Lys8 stabilizes the active conformation of GnRH-III and show the importance of the Trp7. Replacement of the C-terminal Gly-NH2 with D-Ala-NH2 was not well tolerated, but replacement with ethylamide was. Replacement of pGlu1 with Ac-D-Trp appears to have a significantly deleterious effect on a unique conformation of GnRH-III which is responsible for its binding to the receptors on cancer cell lines and the resultant antitumor activity.

Antineoplastic Agents↗
PubMed1996

Effect of gonadotropin-releasing hormone analogs and their conjugates on gonadotropin-releasing hormone receptor--positive human cancer cell lines.

The purpose of the present investigation was to develop new gonadotropin-releasing hormone (GnRH) antagonists and to increase their stability and antitumor effect by conjugation with carrier macromolecules. Antitumor effect was evaluated using clonogenic assay, cell counting for antiproliferation, and sulforhodamine B method. The presence of GnRH-binding sites in human cancer cell lines (MCF-7, MDA-MB-231, Ishikawa, LNCaP) was proved. The direct growth inhibition of tumor cell lines is achieved with relatively high analog concentrations (10(-10)- 10(-5) M). We have developed new GnRH analogs of human and chicken origin. MI-1544 (Ac-D-Trp1,3,D-Cpa2,D-Lys6,D-Ala10)GnRH and the chicken GnRH antagonist MI-1892 (Ac-D-Trp1,3, D-Cpa2, Lys5, [beta-Asp(DEA)]6, Gln8, D-Ala10)-GnRH have stronger direct antitumor properties than the agonists. The antagonists inhibited proliferation of GnRH receptor-positive human cancer cell lines by 28 to 38%. GnRH peptide analogs were coupled with macromolecules through biodegradable groups, to enhance their antitumor effects. The antagonists reduced survival of MCF-7 and MDA-MB-231 cells by 38 to 48% and 20 to 41%, respectively. They showed less activity against human endometrial and prostate cancer cells (10-20%). The copolymer (P) as polyanionic carrier molecule reached only 15 to 20% survival reduction in all cell lines. However, the copolymer GnRH antagonist conjugates P-X-1892 and P-X-1544 killed 95 to 98% of cells at doses corresponding to the GnRH analog concentration. These compounds having antitumor activity could be tried for the treatment of prostate, breast, and endometrium cancer.

Antineoplastic Agents, Hormonal↗
PubMed1994

Dominant expression of multidrug resistance in intraspecific murine lymphoma hybrid cells.

Cultured P388/VCR mouse lymphoma cells resistant to vincristine (VCR) and to 5-bromodeoxyuridine (BUdR) and deficient in thymidine kinase (TK-) were fused with P388/DAG cells resistant to 1.2:5,6-dianhydrogalactitol (DAG), an anticancer alkylating agent, and to 6-thioguanine (6-TG) and deficient in hypoxanthine phosphoribosyl-transferase (HPRT-). The hybrid cells expressed multidrug resistance (MDR), i.e., resistance to VCR and cross-resistance to Adriamycin (ADM) and actinomycin D (Act. D), in a dominant manner. The presence of glycoprotein p170, the MDR gene product, was detected in the hybrid cells. Resistance to DAG was also expressed dominantly, whereas cross-resistance to dibromodulcitol (DBD), a chemically related anticancer drug, was slight.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1981

Drug resistance studies on intraspecific hybridomas.

P388 mouse leukemia lines, one sensitive (P388/S) and the other resistance (P388/R) to vincristine (VCR), cultured in vitro, were hybridized with polyethylene glycol (PEG). A thymidine kinase-deficient mutant (TK-) was isolated from the sensitive line, and a hypoxanthine-guanine phosphoribosyltransferase-deficient mutant (HPRT-) from the resistant line. The hybrid line grows slower than the mutants. The modal chromosome numbers are: TK- = 38, HPRT- = 40, hybrid = 69 (72). The TK- cells contain a large metacentric marker which is missing from the HPRT- cells. Hybrid cells are as resistant to VCR as the P388/R and HPRT- cells.

Animals↗
PubMed1980

Complex evaluation of the effect of some cytostatic hexitol derivatives.

The antitumor effect of three structurally closely related alkylating hexitol derivatives (DBD, DAG, DiacDAG) was evaluated using a complex multi-parameter evaluation system. It comprised toxicology, action on ascites and solid tumors, as well as on subpopulations isolated by isopyknic centrifugation, cross-resistance and their action on chromatin components (DNA, histone, nonhistone proteins). The results indicate that in spite of their same mode of action, considerable differences could be observed in tumor specificity, inhibition of tumor growth and in their interaction with chromatin components. This multiparameter system seems to be very useful for comparative studies of other alkylating agents, especially for the evaluation of the effect of chemically closely related compounds.

Animals↗
PubMed1980

Heterogeneity of tumor cell populations.

Ascites tumor cell populations proved to be heterogeneous with respect to density. Subpopulations separated by isopycnic centrifugation differed from each other in several respects including cell cycle time, chromosome number and distribution and chemotherapeutic sensitivity. The results indicate that density separation is a useful technique to study the behavior of subpopulations within tumor and offers new possibilities in comparative experimental chemotherapy.

Animals↗
PubMed1976

Primary cardiac neurilemoma.

A rare case of primary cardiac neurilemoma arising in the right atrium is reported. The patient was a 55-year-old woman who was treated for 20 years with drug and radiation therapy for a metastatic ovarian carcinoma. The cardiac tumor was an incidental finding at autopsy. Both light and electron microscopic examination of the tumor confirmed the Schwann cell origin of the neoplasm. Review of the literature reveals only one other unequivocal report of a primary cardiac neurilemoma.

Autopsy↗
PubMed1975

Proliferation and morphology of ascitic cells as a function of age in cell culture.

Ascitic cells in the logarithmic growth phase increase the accumulation of glycogen particles in the course of explantation into suspension culture, probably due to the increasing arrest of glycogenolytic enzymes. At this age, a part of the cells are capable of restitution by exopinocytosis of the glycogen-containing vacuoles ia formation of cytoplasmic buds. Older cells, taken from the plateau-phase, pass atypical differentiation and ageing, are less capable of hindering the abnormal accumulation of glycogen and the hypervacuolisation. As a consequence, the cells finally degenerate and die.

Animals↗