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PubMedDate not supplied

Synthesis, receptor binding, and crosslinking of photoactive analogues of neuropeptide Y.

Five photoactive analogues of porcine neuropeptide Y (NPY), a 36 amino acid hormone of the pancreatic polypeptide family, have been synthesized by solid phase peptide synthesis method, Fmoc/tBu strategy and carefully characterized. The analogues contain the photoactivatable amino acid 4'-(3-trifluoromethyl)-3H-diazirine-3-yl-phenyl-alanine ((Tmd)Phe) individually at different positions (1, 20, 21, 27 or 36) instead of tyrosine in the wildtype sequence. Affinity to membranes prepared from SMS-KAN cells, which stably express the Y2 receptor has been investigated by measuring the displacement of 125I-Bolton Hunter-NPY. After incubation of the membranes with different concentrations of the crosslinker and subsequent photolysis, the specific binding of 125I-Bolton Hunter-NPY at those membranes was tested in order to quantify the crosslinking efficiency. Whereas [(Tmd)Phe20] NPY, [(Tmd)Phe21] NPY and [(Tmd)Phe27] NPY revealed highest affinity to the Y2 receptor, crosslinking was most efficient when Tyr36 was replaced by (Tmd)Phe. This is in good agreement with the previously suggested C-terminal binding site of neuropeptide Y.

Affinity Labels↗
PubMed1989

Comparison of cyclophosphamide and diaziquone in a retinoblastoma xenograft model.

The benefits and optimal applications of chemotherapy in the management of retinoblastoma remain to be defined. There are major obstacles to its further study in the clinical setting. A xenograft model of human retinoblastoma heterotransplanted directly into the anterior chamber of the nude mouse eye has been adapted for evaluation of therapeutic efficacy. Cyclophosphamide, the most effective conventional drug, and diaziquone, an experimental agent, both produced documented and comparable responses in each of four xenograft cell lines. There was no evidence of rapidly emerging drug resistance or cross-resistance between two agents when sequential chemotherapy courses were given. Diaziquone is an effective chemotherapeutic agent for retinoblastoma in the xenograft model, and may have applications in clinical management.

Animals↗
PubMed1984

The pharmacology of diaziquone given in intravenous or intracarotid infusion to normal and intracranial tumor-bearing puppies.

Diaziquone (also called "aziridinyl benzoquinone," or AZQ), an antitumor drug designed to penetrate the blood-brain barrier, has demonstrated activity against central nervous system (CNS) neoplasms. Four-hour infusions of carbon-14 (14C)-labeled AZQ (0.8 mg/kg) were given via the left common carotid artery or left brachial vein to two groups of puppies. A third group, harboring a transplantable canine glioma, received 14C-AZQ by intravenous infusion. Levels of chloroform (CHCl3)-extractable 14C (AZQ only) and total 14C (AZQ and metabolites) were determined in serial samples of plasma and cerebrospinal fluid (CSF). At the end of the infusion time, total and CHCl3-extractable 14C levels were determined in brain and tumor. Intra-arterial infusion of AZQ caused no histological abnormalities in the retina or brain. For the intravenous infusion group, the concentrations of CHCl3-extractable 14C (in nmol/ml or nmol/gm) were 0.68, 0.35, and 0.84 for plasma, brain, and CSF, respectively. For the intra-arterial infusion group, the concentrations were 0.25, 0.13, and 0.32 for plasma, brain, and CSF, respectively. Comparison of right and left hemispheres following intra-arterial infusion showed a slightly higher concentration of 14C in the ipsilateral (left) hemisphere, with concentrations (nmol/gm) of CHCl3-extractable 14C/total of 14C of 0.15/0.87 on the left and 0.12/0.65 on the right. Concentrations (nmol/gm) of CHCl3-extractable 14C/total 14C in brain and tumor were 0.60/1.24 and 0.58/1.65, respectively. In tumor-bearing animals, tumor and surrounding brain contained similar concentrations of AZQ, but there were higher concentrations of metabolites in tumor. This may reflect different metabolism of AZQ within brain and tumor or different permeability to metabolites. This study revealed that AZQ enters the CNS and brain-tumor tissue in substantial concentrations and that there is no significant advantage to intracarotid infusion of AZQ.

Animals↗
PubMed1976

[Individual variation in the frequency of chromosome aberrations under the influence of chemical mutagens. I. Inter-cultural and inter-individual variations in the effect of mutagens on human lymphocytes].

The study of the distribution law of human peripheral blood cultures for the sensitivity to thiophosphamide was performed. In the first experiment the blood from one person was used, in the second one the blood was used from different persons. "The percent of aberrant cells" and "the number of chromosome breaks per 100 cells" were scored. The distribution law of the cultures in all the experiments was found to be normal. Analysis of the variances on the percent of aberrant cells showed that the distribution law of the cultures received from one donor corresponded to the binomial one, and that of the cultures received from different donors--to the Poisson's one.

Alkylating Agents↗
PubMed1976

[Chromosome aberrations induced by fortrin in human lymphocytes in cultures and in vivo].

Chromosome aberrations in human lymphocytes in vitro and in vivo were studied after the treatment with the five-functional alkylating agent photrine (an original Soviet antitumour drug). In concentrations above 10-7 M photrine caused chromosome breaks in vitro at 4.6.10-4 M completely diminished the mitotic activity in cultured cells. The aberrations were presented almost exclusively as single and paired fragments occasionally distributed among the chromosomes. In three patients treated with photrine cells with aberrative karyotypes ranged within 14-37.5%.

Adenocarcinoma↗
PubMed1976

Interaction of antitumor agents including carboquone in sarcoma-180 system.

Combination effect of antitumor agents including carboquone was evaluated on the concept of pharmacological synergism and not therapeutic synergism in ascites sarcoma-180 system. Combinations of carboquone plus cyclophosphamide, doxorubicin, and Methotrexate in simultaneous administration and carboquone plus doxorubicin in alternate one provided synergism. Combination effect of agents was affected by the schedule of drug administration. Toxicity of carboquone in combination with many antitumor agents, generally, decreased in simultaneous administration. Approved agents in combination with carboquone in simultaneous administration were Mitomycin-C, daunorubicin, Actinomycin-d, vinblastine, vincristine, Ancytabine, and 6-mercaptopurine. Those in alternate administration were Actinomycin-D and vinblastine.

Animals↗