ABSTRACT
Under stress conditions, polyamines decreased the permeability of the outer membrane of Escherichia coli. This effect is caused by at least three mechanisms providing for an increase in the resistance to antibiotics transported through porin channels (fluoroquinolones, beta-lactams): a positive modulation of the gene micF transcription (its product antisense RNA inhibits the synthesis of porin proteins on the translational level); a positive effect on the cell content of the multiple stress resistance factor sigma(S) (it is accompanied by a decrease in the porin transport because of suppression of ompF transcription and induction of cadaverine synthesis); a direct inhibition of the transport activity of porin channels. The production of cadaverine in E. coli cells significantly increased in response to various antibiotics, and this was likely to be a manifestation of oxidative stress.
Subject(s)
Drug Resistance, Bacterial/drug effects , Escherichia coli/drug effects , Polyamines/pharmacology , Bacterial Proteins/biosynthesis , Oxidative Stress , Porins/metabolism , Putrescine/pharmacology , Salicylates/pharmacology , Sigma Factor/biosynthesisABSTRACT
Blood lymphocyte ability for DNA reparation in response to injuring DNA test-exposure of x-radiation in vitro at a dose 250 Gy was investigated in 158 patients with breast and genital tumors and 40 donors. Suppression of the DNA reparative synthesis before a regular course of cancer therapy (which did not depend on a nosological entity, type and number of cancer therapy courses) was noted in 61% of the patients. However the frequency of such patients was significantly increased with regard to tumor spreading. Individual differences in the ability of cancer patients' lymphocytes for reparation before therapy can reflect, to a certain extent, their function and serve as an additional criterion for predicting complications of cancer therapy.
Subject(s)
Breast Neoplasms/blood , DNA Repair/radiation effects , DNA/blood , Genital Neoplasms, Female/blood , Lymphocytes/radiation effects , Adult , Breast Neoplasms/therapy , Cells, Cultured/drug effects , Cells, Cultured/metabolism , Cells, Cultured/radiation effects , Combined Modality Therapy , DNA/drug effects , DNA/radiation effects , DNA Repair/drug effects , Female , Genital Neoplasms, Female/therapy , Humans , Lymphocytes/drug effects , Lymphocytes/metabolism , Middle Aged , VeinsABSTRACT
A study was made of the level of reparative capacity of peripheral blood lymphocytes of cancer patients in response to DNA damaging R-radiation testing at a dose of 250 Gy before the next course of cancer chemotherapy. A low capacity of peripheral blood lymphocytes for reparation of DNA or its complete suppression is characteristic for most cancer patients irrespective of a nosological entity and the number of cancer chemotherapy courses in their history. The frequency of cancer patients with the initially suppressed capacity of peripheral blood lymphocytes for DNA reparation has an increasing tendency depending on the spreading of a process. These data can serve as an additional criterion of prognosis of complication during antitumor therapy.
