SEARCH · Search PubMed
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Three chemical derivatives of mitomycin C cause loss of viability, inhibition of deoxyribonucleic acid synthesis, and inhibition of cell division in bacteria. Each of these drugs lacks the C(1)-C(2) aziridine ring previously postulated to be essential for the bactericidal effect of mitomycin C.
An Escherichia coli K-12 strain and its mutant, temperature-sensitive in deoxyribonucleic acid (DNA) synthesis, were used as hosts for two different ColB factors (ColB3-K166 and ColB4-K98). Induction of either colicin occurred in both hosts in the presence of mitomycin C at 42 C. Induction of the temperature-sensitive colicinogenic hosts also occurred without mitomycin C at 42 C at which temperature no DNA synthesis was observed. Colicin synthesis was a nonlethal event in ColB4-K98(+) cultures, whereas in cultures of ColB3-K166(+) induction led to death of a large fraction of the population.
Muschel, Louis H. (University of Minnesota, Minneapolis), and Karen Schmoker. Activity of mitomycin C, other antibiotics, and serum against lysogenic bacteria. J. Bacteriol. 92:967-971. 1966.-Lysogenic bacteria were found to be more sensitive to the bactericidal action of mitomycin C or streptonigrin than the corresponding sensitive or indicator strains. This result may be attributed to the induction of phage production in lysogenic cells by these antibiotics. Lysogenic and sensitive bacteria were, however, equally sensitive to chloramphenicol, streptomycin, and polymyxin B. In contrast to their greater sensitivity to certain phage-inducing antibiotics, the lysogenic state resulted in greater resistance to the bactericidal reaction of serum mediated by the complement system. In general, therefore, the lysogenic state may result in either decreased or increased sensitivity to various antimicrobial agents.
Iyer, V. N. (Microbiology Research Institute, Canada Department of Agriculture, Ottawa, Canada). Mutations determining mitomycin resistance in Bacillus subtilis. J. Bacteriol. 92:1663-1669. 1966.-The pattern of development of genetic resistance in Bacillus subtilis to mitomycin C was studied, and spontaneous single and multistep mutants were obtained. The transmission and expression of these mutations in sensitive strains proved possible by means of genetic transformation. The mutations were genetically studied in relation to a chromosomal mutation, mac-1, which confers resistance to the macrolide antibiotic erythromycin and which has been previously localized in the early-replicating segment of the B. subtilis chromosome. The results indicate that all of three primary mutations studied in this manner, as well as a secondary and tertiary mutation derived from one of the primary mutations, are clustered in this early-replicating segment. It appears that the secondary and tertiary mutations enhance the resistance conferred by the primary mutation, apparently without themselves conferring any resistance.
The charts were reviewed of all patients who underwent primary trabeculectomies (group 1) or combined procedures (phacoemulsification + intraocular lens implantation + trabeculectomy--group 2) and received intraoperative mitomycin C (0.4 mg/ml) between 1991 and 1992 at Wills Eye Hospital. A total of 54 eyes of 54 patients were included: 39 in group 1 and 15 in group 2. Intraocular pressure was controlled successfully in 97.4% of eyes in group 1 (mean follow up 6.7 months), and in 93.3% in group 2 (mean follow up 6.8 months). Main complications included choroidal detachment (n = 15), shallow anterior chamber (n = 9), cataract formation (n = 8), and hypotony maculopathy (n = 3). The use of mitomycin C in primary trabeculectomies and combined procedures is associated with high success rates. However, it may be associated with unacceptable risks of vision threatening complications related to excessive filtration.
AIM: To prevent scarring after surgical optic nerve sheath decompression, it has been suggested that treating the area of fenestration with mitomycin C (MMC) might be effective. An animal model was used to test whether this toxic substance may cause optic neuropathy. METHODS: The optic nerves of 15 rabbits were exposed to balanced salt solution (BSS) or mitomycin C (MMC) in a concentration of 0.2 or 0.5 mg/ml. The unoperated fellow eyes and the eyes that received BSS served as controls. Steady state visual evoked potentials (VEPs) at 40, 50, and 60 Hz were recorded before and 4 weeks after surgery. The nerves were examined by light and electron microscopy after 5 weeks. RESULTS: VEPs in all non-operated eyes and eyes treated with BSS before and 4 weeks after surgery demonstrated responses at all three stimulus frequencies tested. Eyes operated with MMC had extinguished responses for one, two, or all the different temporal frequencies after 4 weeks with marked reduction in VEP amplitude. Eyes operated with MMC at a concentration of 0.5 mg/ml had significantly more reduced VEP responses than those where MMC 0.2 mg/ml was used. On histopathological examination, special stains for myelin and axons showed normal axons and myelin. On electron microscopy, no distinct abnormalities were seen among nerves operated with MMC and controls. CONCLUSION: The data from this study suggest that in rabbits, the application of MMC to the optic nerve has a dose dependent toxic effect in the short term postsurgical follow up period. While a functional alteration could be demonstrated reproducibly by steady state VEPs, the extent was not obvious on histopathological examination of the nerves.
AIM: To verify if partial intraoperative Tenon's capsule resection (PTCR) with adjunctive mitomycin C is effective in developing thin, avascular blebs in eyes undergoing Ahmed glaucoma valve insertion, and to assess the efficacy and safety of this procedure. METHODS: A multicentre, prospective, alternating case assignment, investigator unmasked, parallel group, comparative interventional study was conducted in four Latin American countries (Argentina, Brazil, Colombia, and Peru). Ahmed glaucoma valve implant insertion with PTCR (group A) and without PCTR (group B) was performed in neovascular glaucomatous eyes without previous surgery. Adjunctive mitomycin C (MMC) was used in both groups. Patients were examined 1 day, 10 days, 1 month, 2 months, 3 months, 6 months, and 1 year following the surgery. Intraocular pressure (IOP) and the appearance of the bleb were evaluated at each examination. Appearance of the bleb was classified at both the 1 month mark and last examinations into one of three groups: flat and vascularised; elevated avascular; or elevated and not avascular. RESULTS: 92 eyes from 92 patients were included in the study. The preoperative mean IOP was 50.0 (SD 10.5) mm Hg in group A and 48.4 (11.7) in group B (p>0.05). Statistically significant IOP reductions were observed at all periods of follow up. 12 months after surgery, the mean IOP was 17.2 (5.0) mm Hg in group A and 18.3 (8.7) mm Hg in group B (p>0.05). A hypertensive phase occurred in 40.0% in group A and in 46.8% in group B (p>0.05). At the 1 month and the final follow up, the blebs in all eyes were considered elevated and not avascular. The success rate (IOP</=21 mm Hg) at 1 year after surgery was 70.4% in group A and 77.7% in group B (p>0.05). Overall, 74.2% of the patients achieved an IOP </=21 mm Hg and 55.2% an IOP</=17 mm Hg, with or without additional medication administered to lower IOP. The incidence of complications was similar in both groups. CONCLUSIONS: In eyes undergoing Ahmed valve implantation for neovascular glaucoma, PCTR with MMC augmentation showed no additional benefits or complications over MMC augmentation alone; no avascular bleb was obtained with this technique. The incidence of a hypertensive phase was lower than reported in previous studies.
We report an infant with pre- and postnatal microcephaly and growth retardation, a distinctive face, and developmental delay. The initial diagnosis was of Seckel syndrome. He became pancytopenic at 16 months and died soon after. His bone marrow was of normal cellularity but had a small lymphocyte infiltration. Increased spontaneous chromosome breakage was seen in blood and fibroblasts. Mitomycin C induced chromosome damage was increased and comparable to that seen in Fanconi anaemia. Reports of similar patients are reviewed. This entity of severe intrauterine growth retardation and increased mitomycin C sensitivity is hypothesised to be a distinct chromosome breakage syndrome.
Thiobacillus novellus is highly resistant to mitomycin C and rifampicin. This resistance is not due to insusceptibility of the target molecules to the drugs, since mitomycin C cross-links the DNA and rifampicin inhibits the DNA-dependent RNA polymerase of T. novellus in vitro.
The extent of alkylation of DNA by dimethyl sulfate, nitrogen mustard, and the antibiotic mitomycin C is related to the resulting decrease in the fluorescence of intercalated ethidium. The fluorescence losses due to the first two types of reagents show a marked pH dependence, with greater losses of fluorescence being observed at alkaline pH values. At pH 11.6 the fluorescence shows a slow recovery, so that with low levels of methylation (4% deoxyguanosine residues modified) one observes complete return of fluorescence. We postulate that these phenomena are due to conversion of 7-methyldeoxyguanosine to the zwitterionic form, and partial denaturation of the DNA duplex with loss of ethidium binding sites. Hydroxide-ion-catalyzed imidazole ring opening, and the removal of the positive charge permits reannealing with concomitant return of the ethidium intercalation sites. This conclusion is substantiated by enzymatic hydrolysis of 14C-labelled methylated DNA and identifiions of the ethidium assay. The distinctly different behavior of mitomycin C confirms previous conclusions that its alkylation, preferentially on guanine, does not take part at the N-7 position.
Chuling (Polyporus umbellatus), one of the commonly used Chinese medical herbs, was combined with mitomycin C and then studied against intrahepatic implantation of sarcoma 180 tumor cells in mice. Oral administration of chuling extract, intraperitoneal injection of mitomycin C and the combination of both increased the life span of tumor-bearing mice 71.6%, 70.1% and 119.9%, respectively. The same treatments were found to be cytotoxic to Sarcoma-180-induced liver tumor cells. The synthetic rates of DNA, RNA and protein were all inhibited measurably by the combined treatment. Histopathological studies showed that lymphocytes infiltrated and surrounded the cancer cells, and there was some fibrosis found in normal cells and cancer cells. These results indicate the potential use of chuling as an anticancer agent.
PURPOSE: The purpose of this study was to report the pharmacokinetics of heated intraoperative intraperitoneal mitomycin C (MMC) and to analyze the impact of heat, extent of peritoneal resections, and effect of intraoperative hyperthermic chemotherapy on the pharmacological properties of the peritoneal plasma barrier. METHODS: Sixty patients with peritoneal carcinomatosis were included in a phase I/II study combining cytoreductive surgery with 2 h of heated intraperitoneal mitomycin C in an intraoperative lavage technique and one cycle of early postoperative 5-fluorouracil (5-FU) given on postoperative days 1-5. Three pharmacokinetic analyses were performed: (1) pharmacokinetics of heated intraoperative intraperitoneal MMC was determined for 18 patients by sampling peritoneal fluid, plasma, and urine during the 2-h procedure; (2) impact of peritoneal resections on MMC pharmacokinetics was assessed by comparing a group of patients who underwent < or = 1 peritonectomy procedure (minimal surgery) to a group of patients who underwent > or = 2 peritonectomy procedures (extensive surgery), and (3) effects of heated intraoperative intraperitoneal chemotherapy on the pharmacokinetics of early postoperative intraperitoneal 5-FU by comparing a group of patients treated with heated intraoperative intraperitoneal MMC to a control group who did not receive heated intraoperative intraperitoneal chemotherapy. RESULTS: The mean dose of heated intraoperative intraperitoneal MMC per patient was 22.5+/-7.1 mg (12.9+/-3.8 mg/m2). Drug absorption from perfusate was 14.3+/-2.7 mg. The mean aeras under the curve (AUC) for perfusate and plasma were, respectively, 340+/-138 and 15+/-4 microg/ml x min. The mean AUC peritoneal fluid/plasma ratio was 23.5+/-5.8. Patients who underwent extensive peritoneal resections exhibited a significantly (p = 0.037; Wilcoxon rank test) increased peak plasma concentration of MMC, a significantly (p = 0.029) increased AUC of plasma concentrations and a significantly (p = 0.034) decreased peritoneal fluid/plasma AUC ratio. Pharmacokinetic studies of early postoperative intraperitoneal 5-FU showed no significant difference in plasma AUC, perfusate AUC and AUC ratio between patients who received and those who did not receive heated intraoperative intraperitoneal MMC. CONCLUSIONS: Heated intraoperative intraperitoneal chemotherapy achieves high peritoneal concentrations of MMC with limited systemic absorption. Systemic drug absorption during heated intraoperative intraperitoneal chemotherapy is increased when extensive peritoneal resections are performed, but such slight increases are unlikely to change the risk of systemic drug toxicities. Heated intraoperative intraperitoneal chemotherapy does not alter the pharmacokinetics of early postoperative intraperitoneal 5-FU.
BACKGROUND: The therapeutic potential of chemotherapy in the treatment of recurrent or metastatic non-small cell lung carcinoma (NSCLC) seems modest. Thus, the search for novel agents and combination regimens with a superior therapeutic index has a high priority. The present combination regimen consisting of mitomycin C, vinorelbine, carboplatin and granulocyte-macrophage colony-stimulating factor (GM-CSF) was chosen because of the known activity of these agents in NSCLC and their potential drug synergism without (nonhematologic) cross-toxicity. To prevent/counteract neutropenia that was assumed to represent the dose-limiting toxicity, the hematopoietic growth factor GM-CSF was routinely adminstered. The objective of our trial was to determine the antitumor efficacy and tolerance of this combination regimen in patients with advanced NSCLC. PATIENTS AND METHODS: Forty consecutive patients with nonresectable, measurable NSCLC (stage IIIB, 7; stage IV, 33) were treated with an intravenous combination chemotherapy regimen consisting of mitomycin C 8 mg/m2 on day 1, vinorelbine 40 mg/m2 on days 1 and 21, and carboplatin 250 mg/m2 on days 1 and 21; GM-CSF 5 microg/kg was administered subcutaneously on days 2-8 and 22-28. Treatment cycles were repeated every 6 weeks. All patients are evaluable in terms of toxicity and response assessment. A total of 123 courses was administered. RESULTS: Objective tumor response was notes in 16 patients (40%; 95% confidence interval 24.9-56.7%), including 3 (7.5%) complete and 13 partial responses. There was no change in 12 (31.5%) patients, and 12 had progressive disease. Median duration of response was 6 (range 3-15) months, the median time to progression for all patients was 6.2 (range 1-17.5) months, and the projected median survival time was 8.7 (range 1-23.3) months; the 1-year survival rate was 27.5%. Myelosuppression was the most frequently encountered adverse reaction; WHO grade 3 or 4 granulocytopenia and/or thrombocytopenia occurred in 42.5 and 12.5%, respectively. Other toxicities were generally mild to moderate, and always fully reversible. CONCLUSION: With a 40% major response rate and disease stabilization in one additional third of our patients, this drug combination seems to have significant activity against advanced metastatic NSCLC. Due to its subjective tolerance and ease of administration, further investigation of this regimen in the palliative-intent care setting seems warranted.
Second-line treatment of patients with metastatic breast cancer resistant to anthracyclines is an important clinical issue. The aim of the present two-stage phase II study was to evaluate activity and toxicity of vinorelbine + mitomycin C (VM) in such patients. Fifty-five patients were entered and received vinorelbine 30 mg/m(2) on days 1 and 8 + mitomycin C 10 mg/m(2) on day 1, every 4 weeks, up to 9 cycles. Two complete and 23 partial responses were observed for an overall response rate of 45.4% (95% CI 32.0-59.4). Median survival was 13 months and probability of surviving after a 1-year follow-up was 58%. Toxicity was never life-threatening, but G-CSF was used in 45% of cycles to contrast neutropenia that was the most frequent side effect. These results are consistent with previous studies and strongly support VM being considered among the optimal polychemotherapy regimens for second-line treatment of metastatic breast cancer in clinical practice; for clinical research aims, VM should be used as control arm for randomized trials evaluating the activity of new drugs against breast cancer.
PURPOSE: This study was performed to investigate the activity and safety of high dose 5-fluorouracil (5-FU) given as a weekly 24-hour infusion in combination with folinic acid plus mitomycin C in patients with advanced gastric cancer. PATIENTS AND METHODS: Chemonaive patients with locally advanced inoperable, recurrent or metastatic gastric cancer were treated with 15 mg/m(2) i.v. mitomycin C as bolus on day 1 of a 7-week cycle followed by a 2-hour infusion of folinic acid (500 mg/m(2)) and a 24-hour infusion of 5-FU (2,600 mg/m(2)) given on days 1, 8, 15, 22, 29, and 36 as outpatient treatment. RESULTS: Thirty evaluable patients (median age 58 years and median ECOG performance status 1) received 1-4 cycles (median 3). 53% of the patients had liver metastases. Treatment-related toxicity was low with 10% of patients experiencing diarrhea >/=grade 3, 3% mucositis grade 3 and 3% nausea grade 3 (CTC). Hematological toxicity was mild with 13% thrombopenia grade 3 and no leukopenia grade 4. Eleven patients achieved a partial remission (major response rate 37%; 95% confidence interval 22-53%). Median time to progression was 5 months and median overall survival time was 7 months. CONCLUSION: This regimen is a well-tolerated outpatient treatment for patients with advanced gastric cancer with efficacy being comparable to other chemotherapy protocols.
Mitomycin C is a powerful antineoplastic agent. If used at high dosage, it may cause a secondary form of adult hemolytic-uremic syndrome (HUS). Blood transfusions worsen the evolution of this peculiar form of HUS. We describe a patient who developed HUS after treatment with mitomycin C (total dose 144 mg/m2) due to a carcinoma of the ascending colon. Repeated blood transfusions were associated with rapidly evolving renal failure coupled with anemia and thrombocytopenia. Haptoglobin was undetectable. Soon after starting subcutaneous erythropoietin, the velocity of progression of renal failure slowed whilst no more blood transfusions were required and haptoglobin levels returned to normal. Thereafter, the patient's renal function slowly worsened and she started chronic hemodialysis 5 years later. Up to now, all investigations have failed to show a relapse of her adenocarcinoma. A possible explanation of these data is that erythropoietin permitted the termination of blood transfusions which both triggered and perpetuated the syndrome. However, we cannot exclude a primitive effect of erythropoietin on the endothelium or on the platelets.
Neural crest cells in the pre- and postnatal development of mice showed a specific sensitivity to mitomycin C. In mice injected with mitomycin C 24-48 h after birth and surviving up to the 9th day, a free or attached denticle in the pulp and a fibroma or excessive cell proliferation in the dental follicle or the periodontal ligament were seen; further, a dentinoma developed.
Epstein-Barr virus (EBV) DNA synthesis following EBV P3HR-1 superinfection of the Burkitt lymphoma cell line, Daudi, is refractory to mitomycin C and hydroxyurea at concentrations which inhibit cell DNA synthesis to greater than 98% of control values. Further, neither mitomycin C nor hydroxyurea inhibit virus antigen synthesis following P3HR-1 superinfection.