DNA damage in human transitional cell carcinoma cells after exposure to the proximate metabolite of the bladder carcinogen 4-aminobiphenyl

The DNA damage induced by N-hydroxy-4-acetylaminobiphenyl (N-OH-AABP), the proximate carcinogenic metabolite of the human bladder carcinogen 4-aminobiphenyl (ABP), was examined in human transitional cell carcinoma (TCC) cells after exposure to the chemical in vitro. 32P-postlabeling analysis of TCC cultures exposed to N-OH-AABP revealed a minor adduct identified as 3-(deoxyguanosin-N2-yl)-4-acetylaminobiphenyl (dG-N2-AABP) based on comparison of the HPLC and TLC mobility of the product with the synthetic standard. An adduct with the same chromatographic properties was also detected on postlabeling analyses of calf thymus DNA bound to N-OH-AABP by incubation with horseradish peroxidase and hydrogen peroxide. Detection of dG-N2-AABP, which contains the acetyl moiety, suggests that N-acetoxy-4-acetylamino-biphenyl might be formed as a reactive intermediate and could conceivably arise by a free-radical-mediated reaction of N-OH-AABP with endogenous peroxidases. The radical intermediates could also form reactive oxygen species (ROS). To test this possibility, TCC cultures were exposed to N-OH-AABP and the formation of ROS was measured using 2,7-dichlorofluorescein (DCF) fluorescence assay. TCC cultures exposed to N-OH-AABP showed a dose-dependent increase in the ratio of DCF/DNA fluorescence compared to the untreated controls. Formation of ROS was inhibited by butylated hydroxyanisole (BHA). Furthermore, oxidative DNA damage resulting from ROS was monitored by measurement of 8-oxoguanine products by immunochemical staining and the TCC cells treated with N-OH-AABP revealed a characteristic staining. These results suggest that N-OH-AABP caused oxidative DNA damage as well as bulky covalent adducts in urothelial DNA, possibly involving endogenous peroxidases. These findings show that human uroepithelial cells, which are the target cell types in vivo for arylamine-induced cancers, are metabolically capable of activating these proximate carcinogenic metabolites of arylamines, and these reactions might play a determinate role in the genotoxicity of these environmental carcinogens.     

Comparison of uroplakin expression during urothelial carcinogenesis induced by N-butyl-N-(4-hydroxybutyl)nitrosamine in rats and mice

The expression of uroplakins, the tissue-specific and differentiation-dependent membrane proteins of the urothelium, was analyzed immunohistochemically in N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN)-treated rats and mice during bladder carcinogenesis. Male Fischer 344 rats were treated with 0.05% BBN in the drinking water for 10 wk and were euthanatized at week 20 of the experiment. BBN was administered to male B6D2F, mice; it was either provided at a rate of 0.05% in the drinking water (for 26 wk) or 5 mg BBN was administered by intragastric gavage twice weekly for 10 wk, followed by 20 wk without treatment. In rats, BBN-induced, noninvasive, low-grade, papillary, transitional cell carcinoma (TCC) showed decreased uroplakin-staining of cells lining the lumen but showed increased expression in some nonluminal cells. In mice, nonpapillary, high-grade dysplasia, carcinoma in situ, and invasive carcinoma were induced. There was a marked decrease in the number of uroplakin-positive cells lining the lumen and in nonluminal cells. This occurred in normal-appearing urothelium in BBN-treated mice and in dysplasic urothelium, in carcinoma in situ, and in invasive TCC. The percentage of uroplakin-positive nonluminal cells was higher in control mice than in rats, but it was lower in the mouse than in the rat after BBN treatment. Uroplakin expression was disorderly and focal in BBN-treated urothelium in both species. These results indicate that BBN treatment changed the expression of uroplakins during bladder carcinogenesis, with differences in rats and mice being related to degree of tumor differentiation.     

DNA study of bladder papillary tumours chemically induced by N-butyl-N-(4-hydroxybutyl) nitrosamine in Fisher rats

To examine DNA abnormalities in bladder papillary tumours induced by N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN) in female rats, using image cytometric DNA analysis and cytogenetics. Thirty female rats were exposed to BBN in their drinking water for 20 weeks. One group of 10 animals served as controls. The animals exposed to BBN were killed at a rate of two per week, with the bladder being collected under aseptic conditions and those tumours with exophytic growth removed. The nuclear DNA content of the tumours was evaluated using image cytometric analysis. In two rats part of the tumour pieces was stipulated for culturing. Cytogenetic analysis was performed on at least 30 cells from each cell population and on both tumours. Papillary carcinomas were classified as low grade and high grade. DNA ploidy studies were carried out on 28 low-grade and 21 high-grade papillary carcinomas. Histograms obtained by image analysis showed that a normal urothelium was diploid; 28.6% and 100% of low-and high-grade papillary carcinomas were aneuploid respectively. Both tumours used for cell culture showed multiple numerical and structural chromosome alterations and several marker chromosomes. Image cytometric DNA analysis proved to be a good and reliable method for examining DNA alterations in papillary bladder carcinomas. The present findings establish that the DNA content is statistically different between low-grade and high-grade papillary carcinomas and that deviation from the diploid number is markedly higher in the high-grade ones. In addition, the occurrence of marker chromosomes seems to be related to the aggressiveness of the tumour.     

天津市2019年住院散发急性胃肠炎患儿中诺如病毒感染分子流行病学特征分析

目的:了解天津市2019年散发急性胃肠炎患儿中诺如病毒(Norovirus, NoV)感染的分子流行病学特征。方法:收集2019年1—12月就诊于天津市儿童医院住院散发急性胃肠炎患儿的粪便标本3 116份,收集患儿临床资料和个人信息,采用实时荧光定量PCR方法对NoV进行初筛,应用反转录PCR方法对初筛阳性标本的聚合酶...     

血清HBsAg与HBV DNA水平与乙肝患者肝纤维化程度的相关性分析

目的 探讨血清HBsAg与HBV DNA对乙肝患者肝纤维化的相关性分析.方法 选取2010年5月至2014年9月在我院进行治疗的100例肝脏穿刺活组织学检查的患者,根据肝脏炎症程度将患者分为G0-G1、G2、G3-G4三组,根据不同纤维化分期将患者分为S0-S1、S2、S3、S4四组,根据丙氨酸转氨酶(ALT)水平,将患者分为A1 (ALT≤40U/L)组、A2(40＜ALT≤80U/L)组,对不同分组患者进行血清HBsAg测定、HBV DNA测定及ALT测定,分析其含量与肝脏炎症程度及纤维化程度的相关性.结果 G0-G1组、G2组、G3-G4组HBsAg定量分别为(3.85±0.87)U/ml、(3.54±0.79) U/ml、(2.79 ±0.58) U/ml,三组间具有统计学差异(P＜0.05).G0-G1组、G2组、G3-G4组HBV DNA定量分别为(6.27±1.67) U/ml、(5.68±1.49) U/ml、(5.84±1.59) U/ml,三组间差异无统计学差异(P＞0.05).S0-S1组、S2组、S3组、S4组患者HBsAg定量分别为(3.95±0.93) U/ml、(3.62±0.86) U/ml、(3.55±0.62) U/ml、(3.35 ±0.54) U/ml,四组差异有统计学差异(P＜0.05).S0-S1组、S2组、S3组、S4组患者HBV DNA定量分别为(6.23±1.72) U/ml、(5.79±1.62U/ml)、(5.50±1.48) U/ml、(5.48±1.35U/ml),四组差异有统计学意义(P＜0.05).ALT水平与炎症程度及纤维化程度没有相关性(P＞0.05).结论 HBsAg、乙肝病毒随着肝纤维化程度的加重逐渐减低,血清HBsAg结合HBV DNA载量作为检测乙肝病毒感染者肝纤维化指标更为可靠.     

Cytology of transitional-cell carcinoma of the urinary bladder: diagnostic yield and histologic basis.

The diagnostic yield of cytology in histologically proven transitional-cell carcinoma (TCC) of the urinary bladder has been studied in 100 cases. Cytohistologic correlation rates were 20 percent, 61.7 percent, and 92.8 percent, respectively, for grade 1, 2, and 3 tumors. When further evaluated, G2 cases were segregated into 2 subcategories, G2a and G2b, based on histologic preservation of nuclear polarity, pleomorphism, and other cellular irregularities. Correlation rates were rather low for G2a cases (6/18, 33%) and high for G2b cases, (23/29; 79%). The prevalence of atypical cells was 2 (11.1%) cases in G2a and 16 (55.2%) cases in G2b. The results of this study confirm that cytology has an extremely varying diagnostic yield in urinary bladder TCC. Greater cell exfoliation, increased atypia, and a tendency to infiltration of G2b and G3 cases probably account for the higher diagnostic yield detected in these groups.     

DNA flow cytometry and bladder irrigation cytology in detection of bladder carcinoma

In this study we assessed the role of DNA flow cytometry (FCM) as an adjunct to bladder irrigation cytology to detect carcinoma of the bladder. We selected only those cases who had urinary symptoms and cystoscopic examination or histology-proven cases of bladder cancer who underwent cystoscopy for a follow-up study. Cystoscopy, cytologic examination, and DNA FCM were performed in every case. There were 9 fresh cases and 21 follow-up cases of proven transitional-cell carcinoma (TCC) of the bladder. Cystoscopy revealed growth in all 9 fresh cases as well as in 11 follow-up cases. Cytology was positive in 16 cases, out of which there were 8 each of fresh and recurrent cases. None of the cases showed positive cytology with negative cystoscopy findings. DNA FCM was positive in 13 cases. Aneuploidy was detected in 5 cases, out of which there were 3 hyperdiploid and 2 hypodiploid cases. Nine cases had high (equal or more than 10%) S and G2-M phase cells, ranging from 10-19.36%. One case showed aneuploidy along with high S-G2M phase. Both cytology and DNA FCM were positive in 9 cases. In 2 cases, DNA FCM showed aneuploidy, but cytology and cystoscopy were negative. The sensitivity and specificity of the bladder wash cytology were 80% and 100%, and those for DNA FCM were 55% and 83.3%, respectively. We conclude that both bladder wash cytology and DNA FCM techniques should be done in all the cases of suspected TCC to detect more number of positive cases.     

Effects of Lentinus Edodes, Grifola Frondosa and Pleurotus Ostreatus Administration on Cancer Outbreak, and Activities of Macrophages and Lymphocytes in Mice Treated with a Carcinogen, N-Butyl-N-Butanolnitrosoamine

ICR mice were treated with a carcinogen, N-butyl-N'-butanolnitrosoamine BBN), every day for 8 consecutive weeks and the effects of oral administration of edible mushrooms on the induction of urinary bladder carcinoma and on the activities of macrophages and lymphocytes were studied. Bladder carcinoma were found in all 10 mice (100%) treated with BBN alone, while we observed carcinoma only in 9 of 17 mice (52.9%), in 7 of 15 mice (46.7%) and 13 of 20 mice (65.0%) treated with Lentinus edodes, Grifola frondosa and Pleurotus ostreatus, respectively. Chemotactic activity of macrophages was suppressed in mice treated with BBN alone but maintained almost the normal level in mice treated with BBN plus Lentinus, Grifola or Pleurotus. Lymphocytes collected from mice treated with BBN plus each mushroom showed almost normal blastogenic response against concanavalin A, although those from mice treated with BBN alone completely retarded their response. Cytotoxic activity of lymphocytes against Yac-1 cells was also maintained at a normal level in mice treated with BBN plus each mushroom. Whereas in mice treated with BBN alone significant depression of NK cell activity occurred. Significantly higher cytotoxic activity against P-815 cells was observed in lymphocytes from mice treated with BBN plus each mushroom than that in lymphocytes from normal mice or mice treated with BBN alone.     

Modification of tumor ploidy level via the choice of tissue taken as diploid reference in the digital cell image analysis of Feulgen-stained nuclei.

We studied the influence of five cell nucleus populations taken as diploid standards with respect to the normalization of a human breast carcinoma. Four normal human tissues (lymphocytes, thyroid, liver, and bladder specimens) were taken as external standards, while the normal breast cells "contaminating" the tumor were taken as the internal diploid standard. Nuclear size and nuclear DNA assessments were performed by means of a cell image processor computing the parameters on Feulgen-stained nuclei from fresh imprint smears fixed in an ethanol-formalin-acetic acid mixture. Our results demonstrate that the choice of normal tissue as the diploid standard markedly influences the ploidy level of breast carcinoma. Normalization according to the lymphocytes led to our obtaining a major hyposextaploid G0-G1 DNA peak in the breast cancer. Using thyroid and liver cells as a standard, we obtained a major pentaploid and sextaploid G0-G1 peak, respectively. Using bladder cells or the normal contaminating breast cells within the tumor, we obtained a major tetraploid G0-G1 peak. Finally, the normalization of the normal bladder cells against the liver cells led to our obtaining a near triploid bladder specimen. The reverse feature was also observed, e.g., the obtaining of biologically nonsensical hypodiploid liver cells after normalization against the normal bladder cells. Such postnormalization variations in ploidy level depend upon the mean nuclear size and the mean nuclear DNA content of the normal tissue taken as diploid standard.(ABSTRACT TRUNCATED AT 250 WORDS)     

Immunohistochemically demonstrated variation in expression of cathepsin E between uracil-induced papillomatosis and N-butyl-N-(4-hydroxybutyl)nitrosamine-induced preneoplastic and neoplastic changes in rat urinary bladder

Expression of rat urinary bladder cathepsin E in benign papillomatosis induced by uracil and various stages of N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN)-induced carcinogenesis was investigated immunohistochemically. Seven-week-old, male F344/DuCrj rats were used. In the normal urothelium of control rats, cathepsin E stained in all layers of cells, although in umbrella cells and some basal cells the reaction was relatively weak. In rats given a diet containing 3% uracil for 5 weeks immunoreactivity of cathepsin E in uracil-induced papillomatosis was consistently homogeneous in all layers, but weaker than in normal urothelium. In rats given 0.05% BBN in drinking water for 12 weeks and subsequently maintained without treatment for 48 weeks cells with little cathepsin E, never observed in normal urothelium, appeared at 5 weeks above the basement membrane in the earliest stage of BBN-induced urinary bladder cancer (simple hyperplasia). Throughout the neoplastic process, groups of cells with a little cathepsin E were randomly distributed, with expression in the urothelium being markedly unstable. Almost all areas of squamous cell proliferation in TCC were negative for cathepsin E. Instability of cathepsin E expression in rat urothelium therefore appears characteristic for carcinogenesis and offers the possibility of using this feature as an early biomarker for urinary bladder carcinogenesis.     

Urinary nuclear matrix protein 22 (NMP22): a diagnostic adjunct to urine cytologic examination for the detection of recurrent transitional-cell carcinoma of the bladder.

This study compares urine nuclear matrix protein 22 (NMP22) immunoassay and conventional urine cytologic examination for detecting recurrent transitional-cell carcinoma (TCC) of the urinary bladder. One hundred twenty-eight urine specimens from 107 patients with a history of TCC of the urinary bladder were studied. NMP22 immunoassay and conventional cytologic examination were performed on each specimen. The NMP22 and cytology results were then compared with the results of subsequent cystoscopies/surgical biopsies performed over a 6-mo follow-up period. The sensitivity of urine cytologic study for predicting recurrent TCC was 60%, while the sensitivity of NMP22 assay was 47%. When both NMP22 assay results and the cytologic interpretation were positive for TCC, the positive predictive value of the combined tests was 74%. When both tests showed negative results, the negative predictive power was 81%. Our findings suggest that urine NMP22 assay may represent a useful diagnostic adjunct to conventional urine cytologic examination for the detection of recurrent TCC of the urinary bladder.     

Identification of members of the Burkholderia cepacia complex by species-specific PCR

Definitive identification of the species in the Burkholderia cepacia complex by routine clinical microbiology methods is difficult. Phenotypic tests to identify B. multivorans and B. vietnamiensis have been established; more recent work indicates B. stabilis may also be identified by growth characteristics and biochemical tests. However, attempts to identify genomovars I and III have, thus far, proved unsuccessful. Previously, we demonstrated the utility of two primer pairs, directed to the rRNA operon, to specifically identify the B. cepacia complex in a PCR. One of these primer pairs, G1-G2, only amplified a DNA fragment from genomovars I and III and B. stabilis in a PCR with genomic DNA isolated from prototypical strains representing the five genomovars. Sequence analysis of the rRNA operon for all the genomovars indicated that this primer pair targeted a region shared by these isolates. Further analysis revealed a region of heterogeneity between genomovar III and B. stabilis internal to the amplified product of G1-G2. Primers designed to target this region were tested with prototypical strains following an initial amplification with the G1-G2 primer pair. New primers specific for the prototypical genomovar III and B. stabilis were designated SPR3 and SPR4, respectively. Analysis of 93 isolates representing 18 genomovar I, 13 B. multivorans, 36 genomovar III, 11 B. stabilis, and 15 B. vietnamiensis isolates was performed. DNA from all isolates of genomovars I and III and B. stabilis was amplified by G1-G2. Genomovar III isolates yielded a product with SPR3/G1 while B. stabilis amplified with SPR4-G1. Genomovar I isolates were amplified by either SPR3-G1 or SPR4-G1, but not both. B. multivorans yielded a product with SPR3-G1 but not G1-G2, and B. vietnamiensis isolates were negative in all PCRs. Thus using an algorithm with G1-G2, SPR3-G1, and SPR4-G1 primers in a PCR analysis, genomovar III isolates can be separated from B. stabilis and the identity of B. multivorans and B. vietnamiensis can be confirmed.     

Protective effects of mate tea (Ilex paraguariensis) on H2O2-induced DNA damage and DNA repair in mice

Yerba mate (Ilex paraguariensis) is rich in several bioactive compounds that can act as free radical scavengers. Since oxidative DNA damage is involved in various pathological states such as cancer, the aim of this study was to evaluate the antioxidant activity of mate tea as well as the ability to influence DNA repair in male Swiss mice. Forty animals were randomly assigned to four groups. The animals received three different doses of mate tea aqueous extract, 0.5, 1.0 or 2.0 g/kg, for 60 days. After intervention, the liver, kidney and bladder cells were isolated and the DNA damage induced by H(2)O(2) was investigated by the comet assay. The DNA repair process was also investigated for its potential to protect the cells from damage by the same methodology. The data presented here show that mate tea is not genotoxic in liver, kidney and bladder cells. The regular ingestion of mate tea increased the resistance of DNA to H(2)O(2)-induced DNA strand breaks and improved the DNA repair after H(2)O(2) challenge in liver cells, irrespective of the dose ingested. These results suggest that mate tea could protect against DNA damage and enhance the DNA repair activity. Protection may be afforded by the antioxidant activity of the mate tea's bioactive compounds.     

Cell cycle dependence of N-methyl-N-nitrosourea-induced tumour development in the proliferating, partially resected rat urinary bladder

In the present experiments the dependence of tumour induction upon the different phases of the cell cycle in the proliferating urinary bladder was examined. For stimulation of urothelial proliferation, a one-third resection of the bladder was performed in female Wistar rats. To synchronize the proliferating urothelial cells, hydroxyurea (HU) was given in 23 fractionated, consecutive intraperitoneal doses (0.1 mg/g body weight each) at hourly intervals shortly prior to and during maximal proliferation (between 33 and 55 h following partial cystectomy). The direct-acting urothelial carcinogen N-methyl-N-nitrosourea (MNU) was administered as a single, intravesicular pulse dose (5 mg/kg body weight) during the different cell cycle phases and to control animals with a non-resected, quiescent bladder (G0-phase). The incidence of urothelial bladder tumours was 32.6% in the controls. By comparison, the tumour incidences were 18.9, 9.3, 21.7, 26.3, 25.0 and 30.0%, respectively, when MNU was instilled during the late G1-, early and late S-, G2 + M-, and the early and late postmitotic phase. The results obtained from a total of 283 rats thus clearly document a cell-cycle-specific inhibition of MNU-induced tumour development in the proliferating urinary bladder, particularly when the carcinogen was administered during the early S-phase (P less than 0.016). There were no differences in the histology and extension of the urothelial bladder tumours found in the different experimental groups. MNU has also been shown to produce urothelial tumours in the renal pelvis (overall tumour incidence: 3.2%) and ureters (1.4%) as well as mesenchymal tumours in the bladder (4.9%) and kidneys (1.4%). Conclusions are tentatively drawn about the mechanisms underlying the observed cell-cycle-specific inhibition of urothelial carcinogenesis.     

Cell cycle dependence of N-methyl-N-nitrosourea-induced tumour development in the proliferating,partially resected rat urinary bladder.

In the present experiments the dependence of tumour induction upon the different phases of the cell cycle in the proliferating urinary bladder was examined. For stimulation of urothelial proliferation, a one-third resection of the bladder was performed in female Wistar rats. To synchronize the proliferating urothelial cells, hydroxyurea (HU) was given in 23 fractionated, consecutive intraperitoneal doses (0.1 mg/g body weight each) at hourly intervals shortly prior to and during maximal proliferation (between 33 and 55 h following partial cystectomy). The direct-acting urothelial carcinogen N-methyl-N-nitrosourea (MNU) was administered as a single, intravesicular pulse dose (5 mg/kg body weight) during the different cell cycle phases and to control animals with a non-resected, quiescent bladder (G0-phase). The incidence of urothelial bladder tumours was 32.6% in the controls. By comparison, the tumour incidences were 18.9, 9.3, 21.7, 26.3, 25.0 and 30.0%, respectively, when MNU was instilled during the late G1-, early and late S-, G2 + M-, and the early and late postmitotic phase. The results obtained from a total of 283 rats thus clearly document a cell-cycle-specific inhibition of MNU-induced tumour development in the proliferating urinary bladder, particularly when the carcinogen was administered during the early S-phase (P less than 0.016). There were no differences in the histology and extension of the urothelial bladder tumours found in the different experimental groups. MNU has also been shown to produce urothelial tumours in the renal pelvis (overall tumour incidence: 3.2%) and ureters (1.4%) as well as mesenchymal tumours in the bladder (4.9%) and kidneys (1.4%). Conclusions are tentatively drawn about the mechanisms underlying the observed cell-cycle-specific inhibition of urothelial carcinogenesis.     

Immunohistochemical analysis of bcl-2 expression in transitional cell carcinoma of the bladder.

AIMS: To evaluate the expression of bcl-2 in transitional cell carcinoma (TCC) of the bladder; to compare bcl-2 expression with clinicopathological findings, p53 immunoreactivity, proliferating cell nuclear antigen (PCNA) expression, 2c deviation index (2cDI), 5c exceeding rate (5cER), and the mean nuclear area (MNA). METHODS: Cystectomy specimens from 77 patients with untreated, non-metastatic TCC of the bladder were studied. Expression of bcl-2, p53 and PCNA was detected immunohistochemically using the following monoclonal antibodies: bcl-2/124, DO-7 and PC10, respectively. Nuclear DNA content was analysed using static cytometry. RESULTS: Bcl-2 was expressed in 19 (24.7%) of 77 TCCs and in 74 (96.1%) of 77 normal samples of transitional epithelium (taken from normal tissue adjacent to the tumour in each case). In all cases, bcl-2 immunoreactivity was more intense in normal transitional epithelium than in TCC. In normal transitional epitehlium and superficial TCC bcl-2 immunoreactivity was observed at the basal layer, and not at the invasive front. Bcl-2 immunoreactivity was invesely correlated with histological grade and p53 immunoreactivity, and was not correlated with the pT category, disease progression, PCNA expression, 2cDI, 5cER, and the MNA. No significant correlation was found between bcl-2 expression and overall survival. CONCLUSIONS: Bcl-2 expression in TCC of the bladder seems to be associated with a less aggressive phenotype and does not play an important role in tumour progression.     

Genotoxicity assessment of oxirane-based dental monomers in mammalian cells

The potential use of oxirane (epoxy) monomers in dental composite development raises the concern to test their genetic safety. Oxiranes can interact with DNA resulting in DNA damage, mutations, and possibly carcinogenesis. Our objective was to evaluate DNA damage and cell-cycle disruption in mammalian cells after exposure to epoxy monomers. The experimental oxiranes were Araldite trade mark GY 281, Cyracure trade mark UVR 6105 and 1,3-dioxane-2,2'-1,3-dioxane-5',4'-bicyclo[4.1.0] heptane (DECHE-TOSU). L929 fibroblast cells were incubated with the monomer for 7 and 24 h at 37 degrees C/5% CO(2). After incubation, cells were subjected to DNA damage alkaline unwinding assay and flow cytometry cell-cycle analysis. Lack of DNA damage and cell-cycle effects were observed with DECHE-TOSU. Exposure to subtoxic doses of Araldite trade mark GY 281 or Cyracure trade mark UVR 6105 caused DNA damage and cell cycle disruption. A significant (p < 0.01) effect for Araldite trade mark GY 281 was observed with cell populations in G1 and G2/M when compared to DMSO solvent control. Similar comparisons revealed significant differences in G2/M cell cycle population after 24-h exposure to 100 microM Cyracure trade mark UVR 6105. For comparison, BISGMA was evaluated to produce DNA damage but without cell-cycle effects suggesting DNA repair mechanisms were effective. Our findings with DECHE-TOSU, Araldite trade mark GY 281 and Cyracure trade mark UVR 6105 indicated cell-cycle disruption followed DNA damage.     

Nonspecific esterase reaction in hyperplastic urinary bladder epithelium induced by administration of N-butyl-N-(4-hydroxybutyl)nitrosamine, freezing and formalin instillation in rats

Chronological changes in nonspecific esterase (NSE) activity in hyperplasia of the bladder mucosa in Wistar rats induced by the administration of 0.05% N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) in their drinking water for up to 20 weeks and in reversible regenerative hyperplasia by freeze ulceration and 20% formalin instillation in the bladder were compared. In regenerative hyperplasia foci with strong NSE activity could not be proved throughout the experimental period, while the foci were detected in hyperplastic epithelium induced by BBN treatment for more than 3 weeks. The focus of NSE high activity persisted for 56 weeks after withdrawal of the carcinogen and the focus or area with the same NSE reaction appeared in papilloma and transitional cell carcinoma seen in weeks 7 to 20 of BBN treatment. The appearance of focal strong activity of NSE seemed to be a promising marker for the precursor lesions of bladder tumors. Short uniform, pleomorphic microvilli were observed on the cell surface of preneoplastic and carcinomatous lesions by BBN as well as on that of regenerative hyperplasia after freeze ulceration and formalin instillation.     

Nonspecific esterase reaction in hyperplastic urinary bladder epithelium induced by administration of N-butyl-N-(4-hydroxybutyl)nitrosamine,freezing and formalin instillation in rats.

Chronological changes in nonspecific esterase (NSE) activity in hyperplasia of the bladder mucosa in Wistar rats induced by the administration of 0.05% N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) in their drinking water for up to 20 weeks and in reversible regenerative hyperplasia by freeze ulceration and 20% formalin instillation in the bladder were compared. In regenerative hyperplasia foci with strong NSE activity could not be proved throughout the experimental period, while the foci were detected in hyperplastic epithelium induced by BBN treatment for more than 3 weeks. The focus of NSE high activity persisted for 56 weeks after withdrawal of the carcinogen and the focus or area with the same NSE reaction appeared in papilloma and transitional cell carcinoma seen in weeks 7 to 20 of BBN treatment. The appearance of focal strong activity of NSE seemed to be a promising marker for the precursor lesions of bladder tumors. Short uniform, pleomorphic microvilli were observed on the cell surface of preneoplastic and carcinomatous lesions by BBN as well as on that of regenerative hyperplasia after freeze ulceration and formalin instillation.