Analyses of carcinogen-modified oligonucleotides by fast atom bombardment/tandem mass spectrometry.
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7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
Biomedical subjects
D G Kaufman
Publications and source records attributed to D G Kaufman.
Factors influencing the initiation by gamma rays of hepatocarcinogenesis in the rat.
F344 male rats were irradiated once with 6 G of cesium 137 gamma rays at various times after a two-thirds partial hepatectomy (PH) and then fed a diet containing the liver tumor promoter phenobarbital to evoke the expression of initiated hepatocytes. Yields of hepatocellular neoplasms were enumerated at 45 weeks after irradiation. Although proliferating hepatocytes in regenerating livers appeared to have increased risk of initiation by gamma rays, there was no apparent variation in risk among groups that were treated at times when hepatocytes were in different portions of the cell cycle (G1, S, G2/M). Gamma irradiation delayed the onsets of DNA synthesis and mitosis by proliferating hepatocytes by 18-20 h. The rate of rejoining of radiation-induced DNA strand breaks was analyzed in primary cultures of hepatocytes; 98% of the strand breaks were rejoined within 30 min after irradiation. Efficient repair of certain types of radiation-induced damage to DNA before the damaged DNA is replicated should cause a substantial reduction in the probability of induction of base-substitution mutations. Hepatocellular islands and neoplasms that were initiated by gamma rays may be derived from proliferating hepatocytes which incurred other radiation-induced DNA damages such as chromosomal aberrations.
Animals↗
Benign scrotal tumors masquerading as expanding varicoceles.
Vascular lesions of the scrotum though most often varicoceles, can occasionally represent either benign or malignant tumors containing vascular elements. Two pediatric patients presenting with vascular scrotal masses resembling varicoceles are reported. Histologic interpretation of the operative specimens demonstrated benign tumors of the scrotum. Hemangiomas, hamartomas, or mesenchymal tumors should be especially suspect in the presence of any vascular right scrotal lesion. Because of the infrequency of prepubertal varicoceles, any vascular lesion of the scrotum in this age group should undergo biopsy before simple excision is performed to rule out the presence of malignancy. Early excision of benign mesenchymal tumors is especially important if, as some believe, they eventually dedifferentiate to more malignant tumors later in the lifetime of an individual.
Child, Preschool↗
Aspiration flow cytometry of the testes in the evaluation of spermatogenesis in the infertile male.
Deoxyribonucleic acid (DNA) flow cytometry of testicular tissue has been demonstrated to be a quantitative means of assessing spermatogenesis. This study evaluates testes aspirates and DNA flow cytometry in the evaluation of the infertile male. Testicular tissue obtained from 12 men who underwent bilateral orchiectomy for prostate cancer (group 1) were examined by both flow cytometry and standard histologic technique to assess the correlation between these two modalities. Thirteen men evaluated for infertility (group 2) and requiring histologic evaluation of spermatogenesis underwent both open biopsy and fine needle aspiration of their testes. Histology was independently examined and grouped according to standard nomenclature. Flow cytometric analysis revealed characteristic patterns in the relative numbers of haploid (1C), diploid (2C), and tetraploid (4C) cells. These patterns correlated reproducibly with the histologic diagnoses. DNA flow cytometry of testicular aspirates provides a rapid and reliable quantitative means of assessing spermatogenesis.
Biopsy, Needle↗
The influence of exogenous estrogen use on survival after diagnosis of endometrial cancer.
For examination of the effect of prior exogenous estrogen use on survival after diagnosis of endometrial cancer, 244 endometrial cancer cases newly diagnosed at North Carolina Memorial Hospital, Chapel Hill, North Carolina, between 1970 and 1976 were followed until 1982. Estrogen users (n = 46) were younger, had less advanced disease, and were more likely to be nonobese and white than were nonusers (n = 198). The estimated probability of surviving (Kaplan-Meier) five years after diagnosis was 0.89 for users and 0.53 for nonusers. When adjusted for age, grade, stage, obesity, race, and treatment (using the Cox proportional hazards regression model), the survival probabilities throughout the period of observation for estrogen users continued to be higher. The adjusted hazard rate for a nonuser was 2.05 (95% confidence interval (Cl) 0.96-4.39) times that for an estrogen user. The adjusted hazard rate from endometrial cancer only was 4.01 (95% Cl 1.22-13.21) times greater among estrogen nonusers. The more frequent occurrence of endometrial cancer in an earlier stage and grade among estrogen users may not be the sole cause of their lower hazard rate from this disease.
Adult↗
Specific nonsurgical therapy in male infertility.
Although the objective of this article was to discuss the specific medically treatable causes of male infertility, the reader will be impressed by the fact that many of the treatments seem less than "specific." The need to treat infections to improve fertility is ill defined. The utilization of a scrotal cooling device as "specific" nonsurgical treatment for varicocele is yet to be defined. Immunologic suppression is indeed a specific form of therapy for a measurable phenomenon; unfortunately, the significance of that phenomenon as well as the best means and location of its assessment are undergoing significant reevaluation. An exciting frontier is the prospect of preventing infertility in the patient undergoing therapy for cancer, thus obviating the need for treatment of the ensuing infertility. Before specific therapies can be anticipated to have a predictable beneficial effect, these areas require active investigation to define the problem more clearly.
Adrenal Cortex Hormones↗
Quantitative relationship between initiation of hepatocarcinogenesis and induction of altered cell islands.
We have quantified the initiation of hepatocytic neoplasms and the induction of altered cell islands in regenerating livers of rats given a single treatment with one of three carcinogens before or during the peak of DNA synthesis after partial hepatectomy. For up to 20 wk after treating livers during the peak of DNA synthesis with methyl(acetoxymethyl)nitrosamine (DMN-Ac), hepatocytic neoplasms were not seen. Thereafter, in rats fed the liver tumor promoter, phenobarbital, neoplasms emerged continuously so that by 60 wk after initiation, livers held an average of 5.5 neoplasms. Islands of cellular alteration, identified by their abnormal retention of glycogen on fasting, also appeared to emerge continuously between 20 and 60 wk after initiation. By 60 wk, promoted livers contained about 10,000 islands. In DMN-Ac-initiated, phenobarbital-promoted livers, neoplasms and islands maintained a constant numerical relationship over time with about 1,450 islands emerging for every neoplasm that emerged. This ratio of islands to neoplasms differed according to the type of carcinogen used to initiate hepatocarcinogenesis and depending on whether promotion with phenobarbital was included. In livers initiated with DMN-Ac but not promoted with phenobarbital, the ratio of islands to neoplasms was about 7,750:1. In livers initiated by treatment with (+/-)-7 alpha, 8 beta-dihydroxy-9 beta, 10 beta-epoxy-7,8,9, 10-tetrahydrobenzo[alpha]pyrene at the peak of DNA synthesis and then promoted with phenobarbital, the ratio of islands to neoplasms was 7,200:1. In livers exposed to gamma rays at the peak of DNA synthesis in regenerating livers and promoted, no neoplasms were seen in our sample although islands could be enumerated.(ABSTRACT TRUNCATED AT 250 WORDS)
7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
Endometrial stromal cells in culture: an attempt to understand the genesis and biologic activity of uterine sarcomas.
The genesis of uterine sarcomas in vivo has been difficult to elucidate. The reasons are multifactorial and are compounded by the rarity of these tumors. In an effort to understand the biologic activity of this disease, normal endometrial tissue was subjected to tissue culture, histochemical study, and hormonal manipulation. Protein markers were used to differentiate endometrial epithelium from endometrial stromal cells in culture. The endometrial stromal cells grew rapidly following subculturing and were responsive to hormonal manipulation. When the stromal cells in culture were treated with the carcinogen N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), the resultant morphologic changes mimicked uterine sarcomas grown in culture. These changes appeared to occur in a sequential manner, somewhat analogous to changes occurring in the endometrial epithelium as it undergoes transformation to endometrial adenocarcinoma. These studies, therefore, may serve as a model system in understanding the genesis and biologic activity of uterine sarcomas.
Alkaline Phosphatase↗
Cystic fibrosis presenting in a 45-year-old man with infertility.
Cystic fibrosis commonly is regarded as a disease of childhood associated with severe pulmonary and pancreatic pathological conditions. We report on a previously healthy 45-year-old man who was diagnosed as having cystic fibrosis after presentation with primary azoospermia. The literature is reviewed. Although references are made to late presentations of cystic fibrosis none was found in which the initial complaint was infertility. Primary azoospermia may be the presenting manifestation of cystic fibrosis in the absence of major respiratory symptoms.
Cystic Fibrosis↗
Species differences in the formation of benzo(a)pyrene-DNA adducts in rodent and human endometrium.
The formation of adducts of benzo(a)pyrene metabolites on DNA was investigated in endometrial tissue from humans, hamsters, mice, and rats. anti-Benzo(a)pyrene-7,8-diol-9,10-epoxide was the predominant adduct identified in all the species studied. The amount of (+)-anti-benzo(a)pyrene-7,8-diol-9,10-epoxide bound to DNA from human endometrium was approximately 3 times higher than to DNA from hamster tissue. Among the three animal species examined, the level of this adduct was highest in hamsters and lowest in rats. The high pressure liquid chromatography profiles of adducts formed in endometrium from humans and hamsters were similar, but the specific activity (pmol/mg DNA) of each adduct formed was different. syn-7,8-Dihydroxy-9,10-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene adduct was present in humans, hamsters, and rats but was not detected in mouse endometrium. There was an unidentified adduct present only in rat tissue. Rats had the lowest level of total DNA-bound radioactivity and the largest percentage of this total eluted as an uncharacterized radioactive peak that eluted with water (53%). These results demonstrate that endometrial tissues from humans and three rodent species differ with regard to the quantities and proportions of benzo(a)pyrene-DNA adducts formed from benzo(a)pyrene.
7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
Kinetics of DNA replication in C3H 10T1/2 cells synchronized by aphidicolin.
Aphidicolin is an inhibitor of DNA polymerase alpha and blocks nuclear DNA replication without interfering with mitochondrial DNA synthesis. The efficacy of this mycotoxin as a tool in cell synchronization was evaluated in C3H 10T1/2 clone 8 cells. At concentrations of 1-2 micrograms/mL, aphidicolin quickly reduced the [3H]thymidine uptake to less than 5% of control levels in the first 5 min of incubation. This inhibition was easily reversed by washing and refeeding cells with fresh medium. The synchronization protocol consisted of first blocking cells by confluence arrest, replating them at lower density, and then treating the cells with aphidicolin for 24 h. Once the inhibitor was removed, DNA replication started without any delay. The cell population traversed the S phase in about 8 h and synchronously doubled in cell number. Autoradiography studies revealed a labeling index of 89-93% during the S phase. However, it was also observed that 10T1/2 cells were able to enter S phase in the presence of aphidicolin. The extent of the ensuing replication in the nucleus was dependent on the time that cells remained arrested in early S phase. Analyses of the newly replicated DNA in alkaline sucrose gradients revealed a fairly homogeneous distribution of sizes of nascent DNA in synchronized cells pulse-labeled at the beginning of the S phase. Upon chase in nonradioactive medium, the average molecular weight of the nascent DNA increased linearly with time of DNA synthesis for 2 h. The apparent rate of DNA chain growth determined from pulse and chase experiments was 1.2 micron/min. This rate was strongly inhibited (93%) by aphidicolin at a concentration of 2 micrograms/mL.
Animals↗
Analysis of isoenzymes in normal and carcinogen-treated human endometrial stromal cells in culture.
The isoenzyme patterns of lactate dehydrogenase (LDH), hexokinase, phosphofructokinase, and aldolase were investigated in cultured normal and carcinogen-treated human endometrial stromal cells. Both normal and carcinogen-treated cells had similar phosphofructokinase and aldolase isoenzymes. Distinctive changes in hexokinase and LDH isoenzyme patterns were found in the carcinogen-treated stromal cells. The LDH isoenzyme patterns of the carcinogen-treated stromal cells were shifted toward the muscle LDH forms. This is comparable to the alteration of LDH isoenzyme profiles observed in cell lines established from human uterine sarcomas. The two tissue culture media used affected the LDH isoenzyme patterns of endometrial stromal cells but differences between the LDH isoenzyme patterns of control and carcinogen-treated cells were detected regardless of the growth medium used. Total LDH activity was not significantly different in control and carcinogen-treated stromal cells. The hexokinase isoenzyme patterns expressed by the carcinogen-treated stromal cells were distinctly different from the normal hexokinase patterns. The treated stromal cells contained both hexokinase I and II, whereas the normal cells contained only hexokinase I. Hexokinase and LDH isoenzyme patterns may serve as markers with which to evaluate carcinogen-induced neoplastic changes in cultured endometrial stromal cells.
Cell Line↗
Quantitation by electron microscopy of the binding of highly specific antibodies to benzo[a]pyrene-DNA adducts.
Highly specific antibodies bound to carcinogen adducts in DNA modified with (+/-)7 beta,8 alpha-dihydroxy-9 alpha, 10 alpha-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE I) were quantitated by electron microscopy (EM) visualization and these observations were compared with quantitation of adducts by enzyme-linked immunosorbent assay (ELISA). The antiserum, elicited in rabbits following inoculation with BPDE I-modified DNA, has been found to be highly specific in its recognition of BPDE I-deoxyguanosine moieties. Parallel DNA samples prepared for analysis by ELISA and EM quantitation were randomized, encoded, and analyzed to determine extents of carcinogen modification in double-blind studies. After levels of modification were determined by immunoassays, DNA samples were prepared for EM analysis by incubation with amounts of anti-BPdG-DNA serum in excess of that necessary for complete binding of antibody to antigenic sites. At equilibrium, samples were enzymatically digested with papain in order to cleave anti-BPdG-DNA IgG molecules into Fab fragments in situ. Following column exclusion chromatography, BPdG-DNA-Fab complexes were incubated with ferritin-labeled Fab' fragments of goat [anti-rabbit F(ab')2] IgG in amounts in excess of those necessary for complete binding. When DNA samples were modified to between 0 and 40 fmol adduct/micrograms DNA, excellent agreement was obtained between ELISA quantitation and visualization by EM of antibodies bound to adducts.
7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
Promotion-like enhancement of transformed phenotypes in human endometrial stromal cells.
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Cell Transformation, Neoplastic↗
Histomorphology of human lung cancer.
We have seen that neoplasms can arise at a number of sites through the lung. They arise from a variety of cells populating these sites. And, specific lesions of different cell types have a variety of biological behaviors. Some are very aggressive and spread rapidly throughout the body. Some are slower growing and are more amenable to therapy.
Adenocarcinoma↗
Quantitative relationship between hepatocytic neoplasms and islands of cellular alteration during hepatocarcinogenesis in the male F344 rat.
Hepatocytic neoplasms (nodules and carcinomas) and islands of cellular alteration which display abnormal retention of glycogen on fasting were quantified in F344 male rats at intervals after initiation of hepatocarcinogenesis by the combination of a two-thirds partial hepatectomy with a single treatment with methyl(acetoxymethyl)-nitrosamine during the subsequent peak of DNA synthesis in regenerating livers. In initiated rats fed the liver tumor promoter phenobarbital, yields of neoplasms and islands maintained a constant numerical relationship over time, with one neoplasm emerging for every 1600 islands. Significantly fewer neoplasms developed in rats not fed the phenobarbital, although the numbers of islands observed at 45 and 60 weeks after initiation were not significantly increased by the promoter. The ratio of islands to neoplasms in rats not fed the phenobarbital was about 11,000:1. Dietary phenobarbital appeared to have an effect on initiated hepatocytes (or latent neoplasms) that was not revealed by its effects on the growth and size of the island population.
Animals↗
Histochemical identification of cultured cells from human endometrium.
Histochemical techniques have been applied to the identification of cell types cultured from human endometrium. Previous work from this laboratory characterized two principal cell types found in cultures of endometrium: a mature epithelial cell and another cell which was classified as the endometrial stromal cell based on light and electron microscopy. In this report we compare the histochemical staining of endometrial tissue in frozen sections to that of cultured cells. These results confirm the epithelial and stromal nature of the respective cell types. Several markers were found that could distinguish between cells of epithelial and stromal origin. The enzymes alkaline phosphatase, gamma-glutamyltranspeptidase, peroxidase, and beta-glucuronidase were localized in glandular and surface epithelia in frozen sections and in colonies of epithelial cells in culture. Stroma in frozen sections and cultured stromal cells contained leucine aminopeptidase and fibronectin. Epithelia in sections and in culture could also be distinguished from cells of stromal origin by preferential binding of lotus and peanut lectin. Several other markers were found in both endometrial epithelium and stroma.
Alkaline Phosphatase↗
Promotional effect of diethylstilbestrol on human endometrial stromal cells pretreated with a direct-acting carcinogen.
Chronic treatment with 0.1 microM diethylstilbestrol (DES) increased the expression of phenotypic alterations in human endometrial stromal cells pretreated with the direct-acting carcinogen N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Abnormal morphology, expression of gamma-glutamyltranspeptidase, and the ability to form colonies under restrictive conditions were more pronounced after combined treatment with carcinogen and DES compared to carcinogen or DES alone. This effect did not appear to be due simply to growth enhancement by DES, because acute treatment with DES did not alter colony formation, growth rate or thymidine incorporation into DNA in stromal cell cultures. Neither did the presence of DES after the toxicity of MNNG. DES did cause shifts in the isoenzyme distribution of lactate dehydrogenase which could be indicative of a hormonal response. The results suggest that DES may act as a tumor promoter or cocarcinogen in human cells through a mechanism other than simply stimulating cell proliferation, but that other estrogenic effects may contribute to the promotional process.
Carcinogens↗