RESUMO
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.
Assuntos
Antineoplásicos/uso terapêutico , Leucemia P388/tratamento farmacológico , Leucemia Experimental/tratamento farmacológico , Vincristina/uso terapêutico , Animais , Linhagem Celular , Resistência a Medicamentos , Células Híbridas/efeitos dos fármacos , Cariometria , Leucemia P388/genética , Camundongos , Camundongos Endogâmicos DBA , MutaçãoRESUMO
The existence of a clinically typical Lesch-Nyhan syndrome was observed in a male infant with 18q deletion syndrome. Indirect hypoxanthine-guanine-phosphoribosyl transferase activity determination demonstrated a normal value, and thus the possibility of Lesch-Nyhan syndrome linked to the X-chromosome may be excluded. It is assumed that the uric acid metabolism must be under the primary or secondary effect of one or other of the gene loci on the long arm of chromosome 18, since the existence off a hyperuricaemic syndrome was observed in this 18q deletion patient.
Assuntos
Deleção Cromossômica , Cromossomos Humanos 16-18 , Síndrome de Lesch-Nyhan/diagnóstico , Ácido Úrico/sangue , Diagnóstico Diferencial , Humanos , Hipoxantina Fosforribosiltransferase/sangue , Recém-Nascido , Linfócitos/enzimologia , MasculinoAssuntos
Gota/genética , Ácido Úrico/sangue , Autopsia , Gota/sangue , Gota/patologia , Humanos , Lactente , Rim/patologia , MasculinoRESUMO
The pattern of segregation of hypoxanthine phosphoribosyltransferase (HPRT, E.C. 2.4.2.8) was determined in synchronized Chinese hamster-chick red blood cell hybrids. Three hybrid lines were synchronized at the G1-S boundary. Bromodeoxyuridine pulses were subsequently applied throughout the S phase, and the frequency of the segregant clones was determined. It was found that the segregation of the chicken-specific HPRT phenotype associated with the loss of a chromosome was potentiated by bromodeoxyuridine administered during the first hour following release of the block.
Assuntos
Cricetinae/genética , Cricetulus/genética , Eritrócitos/enzimologia , Células Híbridas/enzimologia , Hipoxantina Fosforribosiltransferase/genética , Animais , Bromodesoxiuridina/farmacologia , Ciclo Celular , Linhagem Celular , Células Cultivadas , Meios de Cultura , Hipoxantina Fosforribosiltransferase/metabolismoRESUMO
The mutation in hypoxanthine phosphoribosyl transferase gene and the induction of sister chromatid exchange (SCE) were comparatively studied treating Chinese hamster ovary cells with the mutagens ethylmethanesulphonate. N-methyl-N'-nitro-N-nitrosoguanidine, Mitomycin C and X-ray. All the agents exerted strong mutagenic effects and showed a dose-dependent relationship for the induction of SCEs.
Assuntos
Troca Genética , Genes , Hipoxantina Fosforribosiltransferase/genética , Mutação , Troca de Cromátide Irmã , Animais , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Cricetinae , Metanossulfonato de Etila/farmacologia , Feminino , Metilnitronitrosoguanidina/farmacologia , Mitomicinas/farmacologia , Ovário , Raios XRESUMO
The segregation of the chick-specific HPRT gene was studied in three Chinese hamster-chick red blood cell hybrid lines. The three lines showed individual segregation kinetics, the segregation taking place in an exponential-like fashion. Bromodeoxyuridine becomes incorporated into the nuclear DNA and increases the spontaneous segregation rate.
Assuntos
Bromodesoxiuridina/farmacologia , Genes/efeitos dos fármacos , Células Híbridas/efeitos dos fármacos , Animais , Ciclo Celular , Galinhas , Células Híbridas/citologia , Hipoxantina Fosforribosiltransferase/genética , Cariotipagem , Fenótipo , Especificidade da EspécieRESUMO
The temporal sequence of mutation to 6-thioguanine resistance was studied in Chinese hamster ovary cells synchronised in S phase. The number of resistant mutants induced following exposure to pulses of bromodeoxyuridine and subsequent selection was significantly greater if BUdR pulses were administered during the first, rather than the second half of S phase. The results are interpreted as indicating that the gene responsible for 6-thioguanine resistance is replicated during the first half of S phase.
