SEARCH · PubMed Health

Results for “PHOSPHORUS AND COMPOUNDS, RADIOACTIVE”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

356 records · Page 20Linked to original sources

PubMed1994

32P-post-labelling analysis of DNA adducts formed by food-derived heterocyclic amines: evidence for incomplete hydrolysis and a procedure for adduct pattern simplification.

Food-derived aminoimidazoazarenes have been shown to be mutagenic and carcinogenic and to form covalent DNA adducts. 32P-Post-labelling analysis of DNA modified with these heterocyclic amines (HA), including 2-amino-3-methyl-imidazo[4,5-f]quinoline (IQ), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), 2-amino-3,4-dimethylimidazo [4,5-f]quinoline (MeIQ), 2-amino-3,7,8-trimethylimidazo[4,5-f]quinoxaline (7,8-DiMeIQx) and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) has resulted in considerable interlaboratory variation in the characteristic patterns of DNA adduct spots, with up to six being detected for each compound. Similar complex patterns were observed when azido-derivatives of HA were photoreacted with calf thymus DNA. When deoxyguanosine 3'-monophosphate was modified with the azido derivatives and analysed using the 32P-post-labelling procedure, one major spot was observed for IQ, 4,8-DiMeIQx, 7,8-DiMeIQx or PhIP and two major spots for MeIQ or MeIQx. In each case, these adducts were chromatographically indistinguishable from the major adducts formed with DNA. No major adduct spots were observed when 3'-phosphate derivatives of deoxyadenosine, deoxycytidine or thymidine were reacted with the azido-derivatives of HA. In an attempt to identify the additional spots, azido derivatives of PhIP or IQ were reacted with the synthetic homopolymer poly(dG).poly(dC), the alternating copolymer poly(dC-dG) or a synthetic oligonucleotide (TTT-GTTTTTTCTTTCCCT): in each case a reduced number of adduct spots were detected. The introduction of an additional nuclease P1 hydrolysis step following the labelling reaction further reduced the number of adduct spots to only one or two major spots. Reversed-phase HPLC analysis showed that the number of peaks of radioactivity was also reduced to one or two, presumably corresponding to the [32P]-5'-monophosphate deoxyguanosine adducts. We suggest that many of the additional spots commonly observed in conventional 32P-post-labelling analysis of HA-modified DNA are adducted oligonucleotides that are partly resistant to hydrolysis by micrococcal nuclease and spleen phosphodiesterase but are susceptible to hydrolysis by nuclease P1.

Animals↗

PubMed1989

32P-postlabeling assay for carcinogen-DNA adducts and other dna modifications.

32P-postlabeling analysis is a recently developed, highly sensitive method for the detection and measurement of covalent DNA adducts. Since the method does not require radioactive carcinogens, it is suitable for DNA of humans exposed to environmental or occupational genotoxicants. The basic procedure entails the enzymatic incorporation of 32P-label into enzymatic digestion products of DNA, the chromatographic separation and autoradiographic detection of the 32P-labeled digestion products and their quantitation by scintillation counting. Since only microgram amounts of DNA are required, the assay is well suited for the analysis of DNA lesions whenever only limited amounts of cells or tissue may be available. Various versions of the assay have been described affording different sensitivities of adduct detection. Under optimal conditions, one aromatic or bulky/hydrophobic adduct in 10(8) - 10(10) nucleotides can be detected and measured (this corresponds to 0.0003 - 0.03 fmol adduct/microgram DNA or 0.1 - 10 nmol adduct/mol DNA-P). The assay has been successfully applied to a variety of mutagenic (genotoxic) as well as non-mutagenic carcinogens. Among the latter are estrogens and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). In addition, the assay detects age-dependent DNA modifications (I-compounds) in animals that have not been knowingly exposed to mutagens/carcinogens. In humans, the 32P-postlabeling assay has been applied to cigarette smokers, iron foundry workers and coke oven workers. Estimation of total aromatic adduct levels in exposed individuals gave values of 1 adduct in 10(6) - 10(8) DNA nucleotides. These values are similar to the total levels of persistent adducts in tissues of animals after exposure to initiating or carcinogenic doses of authentic aromatic geno-toxicants.

Aging↗

PubMed2003

In situ electroporation of radioactive compounds into adherent cells.

We previously developed a technique, termed in situ electroporation, where nonpermeant molecules are introduced through an electrical pulse into adherent cells, while they grow on electrically conductive, optically transparent, indium-tin oxide (ITO). Careful control of the electric field intensity results in essentially 100% of the cells taking up the introduced material, without any detectable effect upon the physiology of the cell, presumably because the pores reseal rapidly so that the cellular interior is restored to its original state. Electroporation of radioactive material is faced with two important considerations: (1) potential for exposure of personnel to irradiation, and (2) the requirement for electroporation of a large number of cells. In this report, we describe a modification in the geometry of the slides and electrodes which permits the use of inexpensive ITO-coated glass of lower conductivity that can be discarded after use, to electroporate large numbers of cells using a minimum volume of radioactive nucleotide solution. The results demonstrate that, using this assembly, the determination of the Ras-bound GTP/GTP+GDP ratios through electroporation of [alpha32P]GTP can be conducted using approximately five times lower amounts of isotope than in previous designs. Moreover, this assembly permits efficient upscaling, which makes the determination of Ras-GTP binding in cells which are deficient in Ras activity possible. In addition, we demonstrate the labeling of two viral phosphoproteins--the Simian Virus 40 Large Tumor antigen, and Adenovirus E1A--through [gamma32P]ATP electroporation using this setup. In both cases, electroporation of the nucleotide can achieve a great increase in the efficiency and specificity of labeling compared to the addition of [32P]-orthophosphate to the culture medium, presumably because the immediate phosphate donor nucleotide itself is introduced, which can directly bind to the target proteins.

Adenovirus E1A Proteins↗

PubMed1990

Monitoring carcinogen actions on DNA by 32P-postlabeling.

Among several recently developed analytical methods, 32P-postlabeling analysis is a highly sensitive method for the detection and measurement of covalent carcinogen-DNA adducts and other DNA modifications. Since the method does not require radioactive carcinogens, it is suitable for DNA of humans exposed to environmental or occupational genotoxicants. The basic procedure entails the enzymatic incorporation of 32P-label into monomeric or dimeric hydrolysis products of DNA, followed by chromatographic mapping and autoradiography of the 32P-labeled digestion products and quantitation by scintillation spectrometry. Microgram amounts of DNA are analyzed; thus the assay is well suited for limited amounts of cells or tissue. Various versions of the assay afford different sensitivities of adduct detection. Under optimal conditions, one aromatic or bulky/hydrophobic adduct in 10(8)-10(10) nucleotides can be detected and measured (corresponding to 0.3-30 amol adduct/microgram DNA or 0.1-10 nmol adduct/mol DNA-P). The assay has been successfully applied to a variety of mutagenic (genotoxic) as well as non-mutagenic carcinogens. In humans, the 32P-postlabeling assay has been applied to DNA specimens from cigarette smokers, iron foundry workers, and coke oven workers. Estimation of total aromatic adduct levels in exposed individuals gave values of 1 adduct in 10(6)-10(8) DNA nucleotides. These values are similar to the total levels of persistent adducts in tissues of animals after exposure to initiating or carcinogenic doses of authentic aromatic genotoxicants. Among the non-mutagenic carcinogens investigated are estrogens, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), choline-devoid diet, carbon tetrachloride, and peroxisome proliferators. In addition, age-dependent DNA modifications (I-compounds) are being detected by 32P-postlabeling in animals that have not been knowingly exposed to mutagens/carcinogens. I-compound profiles and levels are dependent on species, tissue, sex, and diet. Reduced levels of I-compounds have been consistently noted in the target organ of carcinogen-exposed animals and in resulting neoplasms, suggesting that I-compound loss may play a role in carcinogenesis.

Animals↗

PubMed1994

Single-use percutaneous catheters for intraperitoneal P32 therapy.

BACKGROUND: Intraperitoneal (IP) radioactive chromic phosphate (P32) remains investigational in the treatment of patients with ovarian and/or endometrial cancer. Single-use percutaneously placed catheters offer the advantage of therapy without additional surgery. METHODS: Between August, 1986 and October, 1992, 25 patients underwent bedside percutaneous catheter placement under local anesthesia without ultrasonographic or radiologic guidance, using a specialized central venous catheter. RESULTS: Catheter insertion was successful in 22 of 25 patients (88%) with good IP distribution. Of these, 18 of 22 patients (82%) underwent successful catheter placement with one attempt and 4 of 22 (18%) after one to three additional attempts. The technical failure rate was 12%. Multiple catheter placement attempts were associated with an increased incidence of complications (r = 0.63). Bowel entry occurred in 4 of 25 patients (16%) during 5 of 43 attempts at catheter placement (12%) but was without clinical sequelae. The likelihood of bowel entry significantly increased with more than two attempts (P = 0.02). A median of 39 days (range, 7-156 days) elapsed between the preceding laparotomy and catheter insertion. CONCLUSIONS: Percutaneous catheter placement is successful and well tolerated in the majority of patients and should be considered for patients receiving IP P32.

Adult↗

PubMed1989

Formation of DNA and hemoglobin adducts of fluoranthene after single and multiple exposures.

The dose-dependence of hemoglobin binding as well as distribution of fluoranthene and fluoranthene-DNA adducts in various tissues was characterized in male rats 24 h after a single i.p. injection of [3H]fluoranthene. Formation and distribution of DNA adducts after chronic administration of fluoranthene in the diet was also studied. Fluoranthene-derived radioactivity was widely distributed throughout the animal after a single dose, and excreta contained the greatest amounts of radioactivity at all dose levels. Fluoranthene binding to globin was proportional to dose over the range of 2 nmol/kg to 177 mumol/kg, and the adducted protein was cleared at the same rate as unmodified hemoglobin, indicating that the adducts are stable in vivo. In contrast, fluoranthene-DNA adducts were not present at detectable levels in liver or kidney 24 h after one dose; low levels of adducts were found only in the lung at the highest dose level. Chronic administration of fluoranthene in the diet, however, resulted in DNA adduct formation in most tissues examined, including liver, kidney, lung, small intestine, heart, spleen and lymphocytes; adducts were not detectable in testes DNA. The major fluoranthene-DNA adduct found in rat tissues was identified by its chromatographic similarity to the major fluoranthene adduct formed in vitro using microsomally-activated fluoranthene and calf thymus DNA, previously identified as a reaction product of anti-2,3-dihydroxy-1,10b-epoxy-1,2,3-trihydro-fluoranthene with N2-deoxyguanosine. The unusual stability of this diol epoxide at physiological pH may allow transport of this ultimate DNA-binding metabolite to virtually all tissues. These results demonstrate the applicability of the HPLC-32P-postlabelling procedure to detect and quantify fluoranthene-DNA adducts formed in vivo, and suggest that analysis of these adducts in accessible tissues such as lymphocytes may be a means of assessing chronic, high level exposure to fluoranthene. Our results also indicate that hemoglobin adducts of fluoranthene could be useful dosimeters for detecting short-term or chronic exposure to this compound if a suitable method for their detection were developed.

Administration, Oral↗

PubMed1979

The enzymatic preparation of [alpha-(32)P]nucleoside triphosphates, cyclic [32P] AMP, and cyclic [32P] GMP.

A method has been developed for the enzymatic preparation of alpha-(32)P-labeled ribo- and deoxyribonucleoside triphosphates, cyclic [(32)P]AMP, and cyclic [(32)P]GMP of high specific radioactivity and in high yield from (32)Pi. The method also enables the preparation of [gamma-(32)P]ATP, [gamma-(32)P]GTP, [gamma-(32)P]ITP, and [gamma-(32)P]-dATP of very high specific activity and in high yield. The preparation of the various [alpha-(32)P]nucleoside triphosphates relies on the phosphorylation of the respective 3'-nucleoside monophosphates with [gamma-(32)P]ATP by polynucleotide kinase and a subsequent nuclease reaction to form [5'-(32)P]nucleoside monophosphates. The [5'-(32)P]nucleoside monophosphates are then converted enzymatically to the respective triphosphates. All of the reactions leading to the formation of [alpha-(32)P]nucleoside triphosphates are carried out in the same reaction vessel, without intermediate purification steps, by the use of sequential reactions with the respective enzymes. Cyclic [(32)P]AMP and cyclic [(32)P]GMP are also prepared enzymatically from [alpha-(32)P]ATP or [alpha-(32)P]GTP by partially purified preparations of adenylate or guanylate cyclases. With the exception of the cyclases, all enzymes used are commerically available. The specific activity of (32)P-labeled ATP made by this method ranged from 200 to 1000 Ci/mmol for [alpha-(32)P]ATP and from 5800 to 6500 Ci/mmol for [gamma-(32)P]ATP. Minor modifications of the method should permit higher specific activities, especially for the [alpha-(32)P]nucleoside triphosphates. Methods for the use of the [alpha-(32)P]nucleoside phosphates are described for the study of adenylate and guanylate cyclases, cyclic AMP- and cyclic GMP phosphodiesterase, cyclic nucleotide binding proteins, and as precursors for the synthesis of other (32)P-labeled compounds of biological interest. Moreover, the [alpha-(32)P]nucleoside triphosphates prepared by this method should be very useful in studies on nucleic acid structure and metabolism and the [gamma-(32)P]nucleoside triphosphates should be useful in the study of phosphate transfer systems.

Adenosine Triphosphate↗

PubMed1996

CA-125 levels after surgical exploration and radioactive chromic phosphate in ovarian cancer patients.

Trends in CA-125 levels after completion of therapy in ovarian cancer patients who received intraperitoneal radioactive chromic phosphate therapy (32P) after primary surgical resection or second-look surgery were evaluated. Ninety patients who underwent surgical exploration and 32P were reviewed. Twenty-nine patients were excluded due to insufficient number of CA-125 levels or recurrence within 12 months, with 61 patients with serial CA-125 levels and no evidence of disease for 12 months available for analysis. 32P followed initial resection in 24 patients (16 Stage I, 3 Stage II, 5 Stage III). 32P followed chemotherapy and second-look procedures in 37 patients (4 Stage I, 3 Stage II, 27 Stage III, 3 Stage IV). Elevated CA-125 levels were present in 25 (41%) patients within 12 months of 32P (46% after primary exploration, 38% after second-look). The degree of CA-125 elevation (U/ml) was 30-100 (23%), 100-200 (11%), and >200 (7%). Of the 25 patients with an elevated CA-125, the elevation persisted more than 4 months in 11 (44%). All but two patients had normal CA-125 levels by 12 months. An abnormal elevation in CA-125 was seen in 33% of patients 4 months after receiving 32P and abdominal surgery, with values ranging as high as 500 U/ml. Although elevations in CA-125 are reported following surgery alone, the duration of elevation appears to be longer with 32P. Therefore, persistent elevations of CA-125 following 32P between 4 and 12 months should be judged with caution as they may not reflect recurrent disease.

CA-125 Antigen↗

PubMed1969

Quantitative studies on enzymes in structures in striated muscles by labeled inhibitor methods. I. The number of acetylcholinesterase molecules and of other DFP-reactive sites at motor endplates, measured by radioautography.

Di-isopropylfluorophosphate (DFP) labeled with phosphorus-32 was applied to fragments of the diaphragm and sternomastoid muscles of the mouse, in conditions in which it saturated all available sites at the motor endplates. After adequate washing and exchange with unlabeled DFP, single endplates were obtained by microdissection and their radioactivity was found by beta track radioautography. The number of sites phosphorylated by DFP-(32)P per endplate was relatively constant for each muscle: in the sternomastoid, about 9 x 10(7) sites per endplate, in the diaphragm, about 3 x 10(7). Reaction with DFP-(32)P was abolished by prior treatment with unlabeled DFP. Labeling was unaffected by prior fixation in formaldehyde, but was inversely proportional to the time of incubation in the Koelle staining medium, when this preceded labeling. The contribution of acetylcholinesterase (AChase) to this total number of DFP-reactive sites was determined by three methods. The first involved reactivation of the phosphorylated AChase by pyridine-2-aldoxime methiodide (2-PAM), in conditions in which the reactivation of other enzymes would be insignificant. The other two methods involved protection of the active centers of AChase from phosphorylation by labeled DFP by use of 284C51, an inhibitor highly specific for this enzyme, or by use of eserine. Each of these methods indicated that about 35% of the DFP-reactive sites at endplates of the sternomastoid and diaphragm are AChase. The mean number of AChase molecules was thus found to be 3.1 x 10(7) and 1.1 x 10(7)per endplate in sternomastoid and diaphragm, respectively. No significant reaction of labeled DFP with muscle and nerve was observed. Mast cells in the muscle had a concentration of DFP-reactive sites far higher than the endplates.

Acetylcholinesterase↗

PubMed1981

Structural gene products of the murine Ah complex. Differences in ontogenesis and glucosamine incorporation between liver microsomal cytochromes P1-450 and P-448 induced by polycyclic aromatic compounds.

Antibodies against mouse-liver microsomal cytochromes P1-450 and P-448, two polycyclic aromatic inducible cytochromes, were previously developed [Negishi, M. and Nebert, D.W. (1979) J. Biol. Chem. 254, 11015-11023]. Liver microsomes from 3-methylcholanthrene-treated and phenobarbital-treated and control adult mice and 2,3,7,8-tetrachlorodibenzo-p-dioxin-treated adult and fetal mice were examined. Immunoprecipitable radioactivity was measured, following labeling with pyridoxal phosphate/NaB[3H]4 or with 125I-labeled p-aminosulfobenzoic acid/NaNO2 in vitro or with [3H]leucine, [14C]glucosamine, or [32P]O4 in vivo. (a) Induction of cytochrome P1-450 occurs developmentally earlier in gestation than induction of cytochrome P-448 when the mother is treated with polycyclic aromatic compounds. (b) There appears to be a basal form of cytochrome P-448 but no cytochrome P1-450 in control liver microsomes; inducibility of cytochrome P-448 thus ranges between 5--12-fold, whereas that of P1-450 is infinite. (c) Phenobarbital pretreatment induces no detectable P1-450 or P-448. (d) P-448 appears to be either greater in concentration than P1-450 in the membrane or more exposed than P1-450 on the microsomal membrane surface. (e) By the radioimmunoassay methods used, 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced P1-450 and P-448 in Ah-nonresponsive mice are indistinguishable from those in Ah-responsive mice; this is true in both the fetus and the adult. (f) Compared with P-448 expression, the expression of P1-450 is more closely associated with 3-methylcholanthrene-induced aryl hydrocarbon hydroxylase activity, and these two structural gene products are apparently regulated independently. (g) P-448 but not P1-450 appears to be a glycoprotein. These data illustrate further differences between two forms of polycyclic aromatic-inducible P-450 in mouse liver. Neither P1-450 nor P-448 appears to be a phosphoprotein. Neither anti-(P1-450) nor anti-(P-448) precipitates any forms of liver microsomal P-450 from beta-naphthoflavone-treated adult rabbits and, conversely, anti-LM4 (the antibody to rabbit liver microsomal P-450 form 4) does not precipitate any forms of liver microsomal P-450 from 3-methylcholanthrene-treated C57BL/6N mice.

Animals↗

PubMed1994

Biomonitoring of nitropolynuclear aromatic hydrocarbons via protein and DNA adducts.

Nitropolynuclear aromatic hydrocarbons (nitro-PAHs) are widely distributed in the environment. For several chemicals in this class of compounds, mutagenic activity in bacterial and mammalian systems and tumorigenic activity in laboratory animals have been clearly documented. Procedures for assessing the risk to humans from exposure to nitro-PAHs have not been clearly defined, despite the wide-spread occurrence of such agents in the environment and their possible involvement in the etiology of some human cancers. Several methods are available for determining exposure, uptake, and metabolic activation of genotoxic carcinogens in humans. DNA adducts currently are regarded as the most direct markers of genotoxicity. However, several proteins are equally capable of forming adducts with electrophiles derived from xenobiotics. We focused on developing methods to detect and quantify adducts of 1-nitropyrene and 1,6-dinitropyrene with proteins and with DNA. 1-Nitropyrene is the most abundant nitro-PAH in emissions from combustion sources such as diesel engines. Although 1,6-dinitropyrene is far more mutagenic and more tumorigenic than 1-nitropyrene, it is present in the environment at lower levels. Seeking a highly sensitive method, we have utilized the 32P-postlabeling technique to establish the pattern of the DNA adducts formed in rat tissues, as well as in peripheral blood lymphocytes, following administration of both 1-nitropyrene and 1,6-dinitropyrene. We also present results on hemoglobin and albumin adducts formed after administration of these nitro-PAHs. [3H]1-Nitropyrene was given to male or female Fischer-344 or Sprague-Dawley rats by gavage at five dose levels ranging from 0.1 to 1,000 micrograms/kg of body weight. This led to stable hemoglobin adducts, which accounted for 0.08% +/- 0.05% of the dose. The radioactivity associated with hemoglobin following administration of [3H]1-nitropyrene was cleared with a half-life of 13.6 days. This is faster than the clearance of unmodified erythrocytes in the rat (half-life of 30 days). Treating the hemoglobin with 1% hydrochloric acid in acetone, to precipitate the globin, released the radioactivity so that none remained bound to the globin. Rather, the radioactivity remained bound to the heme moiety. To obtain structural information about the heme adducts, we incubated [3H]1-nitrosopyrene and [3H]4,5-epoxy-4,5-dihydro-1-nitropyrene with rat hemoglobin. In each case, [3H] was bound mainly to globin and, to a lesser extent, to the heme moiety.(ABSTRACT TRUNCATED AT 400 WORDS)

Acetylation↗

PubMed1987

Cell cycle-specific effects of sodium arsenite and hyperthermic exposure on incorporation of radioactive leucine and phosphate by stress proteins from mouse lymphoma cell nuclei.

Cultured mouse lymphoma cells incorporated [3H]leucine and [32P]phosphate into nuclear stress proteins within 3 h after exposure to either elevated temperature (45 degrees C) or sodium arsenite. Radiolabeled proteins were detected by autoradiography after two-dimensional polyacrylamide gel electrophoresis. To determine the cell cycle stage specificity of labeling, nuclei were isolated and sorted into two cell cycle phases using a fluorescent activated cell sorter. After either heat shock or sodium arsenite treatment, the majority of [3H]leucine incorporation into stress proteins occurred during the G0 + G1 phase with minimal labeling in the G2 phase. On the other hand, 32P labeling of stress proteins occurred in both the G0 + G1 and G2 phases after exposure to sodium arsenite, while incorporation of 32P was limited after heat stress. Following sodium arsenite treatment, a distinct set of four stress proteins (80-84 kDa) was detected with [3H]leucine only in G0 + G1 phase, but with [32P]phosphate these stress proteins were labeled in both G0 + G1 and G2. There was differential [32P]phosphate labeling between proteins of the 80-84 kDa set during cell cycling. Individual proteins of this set were isolated from gel plugs after sodium arsenite or heat-shock treatment. Coelectrophoresis of proteins from the two treatment groups showed that they had similar electrophoretic mobilities. All four proteins of the 80-84 kDa set (sodium arsenite induced) possessed similar polypeptide maps after digestion with V8 protease. Cytofluorometric analysis demonstrated a reduction in the number of nuclei in both S and G2 phases of the cell cycle two h after heat shock, but not following sodium arsenite treatment. However, there was a significant depression in the number of nuclei in S and G2 4 h after exposure to sodium arsenite and very modest labeling with 32P of stress proteins was observed at this time.

Animals↗

PubMed2003

Adjuvant treatment for early ovarian cancer: a randomized phase III trial of intraperitoneal 32P or intravenous cyclophosphamide and cisplatin--a gynecologic oncology group study.

PURPOSE: To conduct a prospective study of intraperitoneal radioactive chromic phosphate (32P) versus cyclophosphamide-cisplatin (CP) in women with early ovarian cancer at high risk for recurrence (International Federation of Gynecology and Obstetrics stage Ia or Ib grade 3 or Ic or stage II, no macroscopic residual disease) and to compare cumulative incidence of recurrence, overall survival, and relative toxicity. MATERIALS AND METHODS: A total of 251 patients were randomly assigned to treatment with 32P or CP. Twenty-two (8.7%) were ineligible following centralized pathology review. Of the 229 patients included in the analysis, 110 received 32P, and 119 received CP. RESULTS: The cumulative incidence of recurrence at 10 years was 35% (95% CI, 27% to 45%) for patients receiving 32P and 28% (95% CI, 21% to 38%) for those receiving CP. Patients receiving CP had a recurrence rate 29% lower than that of those receiving 32P (P =.15, two-tail test). The death rate for patients treated with CP was 17% lower than that for patients treated with 32P (difference not significant). Combining both arms, the 10-year cumulative incidence of recurrence for all stage I patients was 27% (95% CI, 20% to 34%) compared with 44% (95% CI, 32% to 56%) for stage II patients (P =.01). Both regimens were reasonably well tolerated, but problems with inadequate distribution (7%) and small-bowel perforation (3%) make the otherwise less toxic 32P less acceptable. CONCLUSION: Although there are no statistically significant differences in survival, the lower cumulative recurrence seen with CP and complications of 32P administration make platinum-based combinations the preferred adjuvant therapy for early ovarian cancer patients at high-risk for recurrence.

Adenocarcinoma, Mucinous↗

PubMed1999

32P-Postlabeling of N-(deoxyguanosin-8-yl)arylamine adducts: a comparative study of labeling efficiencies.

32P-Postlabeling is an extremely powerful technique for the detection of DNA adducts. Typically, the quantitation of DNA adducts by (32)P-postlabeling is achieved by relative adduct labeling, via comparison of the radioactivity incorporated into the adducts to that associated with the normal nucleotides. This approach is based on a number of assumptions, the foremost being that normal and adducted nucleotide 3'-phosphates are converted to 3', 5'-bisphosphates with similar efficiencies. To evaluate labeling efficiencies for specific DNA adducts, we conducted a comparative study of the kinetics of phosphorylation by T(4) polynucleotide kinase using 2'-deoxyguanosine 3'-phosphate (dG3'p) and a series of N-(deoxyguanosin-8-yl)arylamine 3'-phosphate adduct standards (dG3'p-C8-Ar, Ar being 4-aminobiphenyl, 3- and 4-methylaniline, and 2,4- and 3,4-dimethylaniline). Phosphorylation of dG3'p and the dG3'p-C8-Ar adducts followed Michaelis-Menten kinetics. The apparent turnover numbers were 40-240-fold lower when labeling dG3'p-C8-Ar adducts compared to that when labeling dG3'p. The apparent specificity constant calculated for dG3'p-C8-4-aminobiphenyl (1.4 microM(-)(1) min(-)(1)) was approximately 4-fold lower than that (5. 4 microM(-)(1) min(-)(1)) found for dG3'p. Apparent specificity constants for the monoarylamine adducts were even lower (0.043-0.23 microM(-)(1) min(-)(1)) and decreased in the following order: 4-methylaniline > 3,4-dimethylaniline > 3-methylaniline > 2, 4-dimethylaniline. Similar experiments conducted with dG3'p-C8-Ar standards for 2-methylaniline and 2,3-dimethylaniline produced very poor and irreproducible labeling. These results indicate that (32)P-postlabeling of dG3'p-C8-Ar adducts is less efficient than that of dG3'p and suggest that normal nucleotides will be labeled preferentially to the arylamine adducts under kinetically controlled conditions. The data also indicate a further decrease in labeling efficiency upon substitution ortho to the amino group (e.g., 2, 4-dimethylaniline). In addition, the ATP concentrations required for optimal labeling were found to be substantially higher than those used in typical (32)P-postlabeling assays. Since the high specific activity of carrier-free [gamma-(32)P]ATP precludes increasing the ATP concentration to a significant extent, these data emphasize the need for using highly efficient adduct enrichment procedures when conducting (32)P-postlabeling analyses of DNA adducts.

Adenosine Triphosphate↗