Genotoxicity of 3-nitrobenzanthrone and 3-aminobenzanthrone in MutaMouse and lung epithelial cells derived from MutaMouse

FE1 lung epithelial cells derived from MutaMouse are a new model system to provide in vitro mutagenicity data with the potential to predict the outcome of an in vivo MutaMouse test. 3-Nitrobenzanthrone (3-NBA) is a potent mutagen and suspected human carcinogen identified in diesel exhaust and urban air pollution. We investigated the mutagenicity and DNA binding of 3-NBA and its main metabolite 3-aminobenzanthrone (3-ABA) in vitro and in vivo in the MutaMouse assay. Mice were treated with 3-NBA or 3-ABA (0, 2 or 5 mg/kg body weight/day) by gavage for 28 days and 28 days later lacZ mutant frequency (MF) was determined in liver, lung and bone marrow. For both compounds, dose-related increases in MF were seen in liver and bone marrow, but not in lung; mutagenic activity was approximately 2-fold lower for 3-ABA than for 3-NBA. With 3-NBA, highest DNA adduct levels (measured by (32)P-post-labelling) were found in liver (approximately 230 adducts per 10(8) nucleotides) with levels 20- to 40-fold lower in bone marrow and lung. With 3-ABA, DNA adduct levels were again highest in the liver, but approximately 4-fold lower than for 3-NBA. FE1 cells were exposed to up to 10 microg/ml 3-NBA or 3-ABA for 6 h with or without exogenous activation (S9) and harvested after 3 days. For 3-NBA, there was a dose-related increase in MF both with and without S9 mix, which was >10 times higher than observed in vivo. At the highest concentration of 3-ABA (10 microg/ml), we found only around a 2-fold increase in MF relative to controls. DNA adduct formation in FE1 cells was dose-dependent for both compounds, but 10- to 20-fold higher for 3-NBA compared to 3-ABA. Collectively, our data indicate that MutaMouse FE1 cells are well suited for cost-effective testing of suspected mutagens with different metabolic activation pathways as a guide for subsequent in vivo MutaMouse testing.     

Folate deficiency increases chromosomal damage and mutations in hematopoietic cells in the transgenic mutamouse model

Folate deficiency causes megaloblastic anemia and neural tube defects, and is also associated with some cancers. In vitro, folate deficiency increases mutation frequency and genome instability, as well as exacerbates the mutagenic potential of known environmental mutagens. Conversely, it remains unclear whether or not elevated folic acid (FA) intakes are beneficial or detrimental to the induction of DNA mutations and by proxy human health. We used the MutaMouse transgenic model to examine the in vivo effects of FA deficient, control, and supplemented diets on somatic DNA mutant frequency (MF) and genome instability in hematopoietic cells. We also examined the interaction between FA intake and exposure to the known mutagen N‐ethyl‐N‐nitrosourea (ENU) on MF. Male mice were fed the experimental diets for 20 weeks from weaning. Half of the mice from each diet group were gavaged with 50 mg/kg body weight ENU after 10 weeks on diet and remained on their respective diet for an additional 10 weeks. Mice fed a FA‐deficient diet had a 1.3‐fold increase in normochromatic erythrocyte micronucleus (MN) frequency (P = 0.034), and a doubling of bone marrow lacZ MF (P = 0.035), compared to control‐fed mice. Mice exposed to ENU showed significantly higher bone marrow lacZ and Pig‐a MF, but there was no effect of FA intake on ENU‐induced MF. These data indicate that FA deficiency increases mutations and MN formation in highly proliferative somatic cells, but that FA intake does not mitigate ENU‐induced mutations. Also, FA intake above adequacy had no beneficial or detrimental effect on mutations or MN formation. Environ. Mol. Mutagen. 59:366–374, 2018. © 2018 Her Majesty the Queen in Right of Canada 2018.     

Ovarian Stem Cell Niche and Follicular Renewal in Mammals

Stem cell niche consists of perivascular compartment, which connects the stem cells to the immune and vascular systems. During embryonic period, extragonadal primordial germ cells colonize coelomic epithelium of developing gonads. Subsequently, ovarian stem cells (OSC) produce secondary germ cells under the influence of OSC niche, including immune system‐related cells and hormonal signaling. The OSC in fetal and adult human ovaries serve as a source of germ and granulosa cells. Lack of either granulosa or germ cell niche will result in premature ovarian failure in spite of the presence of OSC. During perinatal period, the OSC transdifferentiate into fibroblast‐like cells forming the ovarian tunica albuginea resistant to environmental threats. They represent mesenchymal precursors of epithelial OSC during adulthood. The follicular renewal during the prime reproductive period (PRP) ensures that there are fresh eggs available for a healthy progeny. End of PRP is followed by exponentially growing fetal genetic abnormalities. The OSC are present in adult, aging, and postmenopausal ovaries, and differentiate in vitro into new oocytes. During in vitro development of large isolated oocytes reaching 200 μm in diameter, an ancestral mechanism of premeiotic nurse cells, which operates during oogenesis in developing ovaries from invertebrates to mammalian species, is utilized. In vitro developed eggs could be used for autologous IVF treatment of premature ovarian failure. Such eggs are also capable to produce parthenogenetic embryos like some cultured follicular oocytes. The parthenotes produce embryonic stem cells derived from inner cell mass, and these cells can serve as autologous pluripotent stem cells. Anat Rec, 2011. © 2011 Wiley‐Liss, Inc.     

淫羊藿甙腹腔注射对新生大鼠卵巢发育的影响

目的应用淫羊藿甙对新生大鼠进行腹腔注射,了解其对卵泡发育和卵母细胞凋亡的影响。方法用淫羊藿甙对出生后1～8d大鼠腹腔注射50mg/（kg·d）,分别取出生后2、4、8d龄卵巢,用苏木素-伊红（hematoxylin-eoxin,HE）染色观察不同发育阶段卵泡比例,末端脱氧核苷酰基转移酶介导性dUTP切口末端标记（TdT-mediated dUTP Nick-End Labeling,TUNEL）荧光染色检测卵巢内卵母细胞凋亡变化。结果在淫羊藿甙腹腔注射组的新生的鼠中,1、2d龄卵巢内未装配卵泡比例及4、8d龄卵巢内原始卵泡比例均高于对照组;各日龄组卵巢中卵母细胞TUNEL阳性率明显低于对照组。结论淫羊藿甙可能通过延缓卵母细胞巢破裂,抑制原始卵泡的发育启动,减少卵母细胞凋亡从而增加新生大鼠卵巢中卵母细胞的储备量。     

Composition and morphology of lipid droplets from oviduct epithelial cells

This study was undertaken to determine the composition and morphology of lipid droplets in situ and isolated from oviductal epithelial cells and oviductal fluid. Oviductal epithelial cells were harvested enzymatically from oviducts of cows in either the luteal or the follicular stages of the ovarian cycle. Lipid droplets were isolated from cellular homogenates and characterized biochemically using thin layer chromatography. The morphology of lipid droplets in oviductal epithelial cells and in fractions isolated by ultracentrifugation from cellular homogenates was examined by electron microscopy. Lipid droplets isolated from oviduct epithelial cells varied in composition with the ovarian cycle and the oviductal region. There was more total lipid in droplets isolated from cows in the luteal than follicular phase of the ovarian cycle. Most of this difference was due to large amounts of esterified cholesterol present in the samples from luteal-stage animals. The most esterified cholesterol was found in droplets isolated from the oviductal isthmus of luteal cows. Droplets similar in lipid composition to those isolated from epithelial cells were found in oviductal fluid. Four distinct types of lipid inclusions were evident in electron micrographs of oviductal epithelia and characterized as osmiophilic droplets, lipofuscin-like clusters, lamellar structures, and composite bodies. All of the lipid inclusions were found in droplet isolates except for the extracted lipid portion of the composite body. The presence and diversity of oviduct epithelial lipid inclusions suggest that the oviductal epithelium may be very active in lipid metabolism, particularly cholesterol dynamics. © 1993 Wiley-Liss, Inc.     

The development and prevalidation of an in vitro mutagenicity assay based on MutaMouse primary hepatocytes,Part I: Isolation,structural, genetic,and biochemical characterization

As demonstrated in Part I, cultured MutaMouse primary hepatocytes (PHs) are suitable cells for use in an in vitro gene mutation assay due to their metabolic competence, their “normal” phenotype, and the presence of the MutaMouse transgene for reliable mutation scoring. The performance of these cells in an in vitro gene mutation assay is evaluated in this study, Part II. A panel of 13 mutagenic and nonmutagenic compounds was selected to investigate the performance of the MutaMouse PH in vitro gene mutation assay. The nine mutagens represent a range of classes of chemicals and include mutagens that are both direct-acting and requiring metabolic activation. All the mutagens tested, except for ICR 191, elicited significant, concentration-dependent increases in mutant frequency (MF) ranging from 2.6- to 14.4-fold over the control. None of the four nonmutagens, including two misleading, or “false,” positives (i.e., tertiary butylhydroquinone [TBHQ] and eugenol), yielded any significant increases in MF. The benchmark dose covariate approach facilitated ranking of the positive chemicals from most (i.e., 3-nitrobenzanthrone [3-NBA], benzo[a]pyrene [BaP], and aflatoxin B₁ [AFB1]) to least (i.e., N-ethyl-N-nitrosourea [ENU]) potent. Overall, the results of this preliminary validation study suggest that this assay may serve as a complimentary tool alongside the standard genotoxicity test battery. This study, alongside Part I, illustrates the promise of MutaMouse PHs for use in an in vitro gene mutation assay, particularly for chemicals requiring metabolic activation. Environ. Mol. Mutagen. 60:348–360, 2019. © 2019 The Authors. Environmental and Molecular Mutagenesis published by Wiley Periodicals, Inc. on behalf of Environmental Mutagen Society.     

Tissue-specific metabolic activation and mutagenicity of 3-nitrobenzanthrone in MutaMouse

3-Nitrobenzanthrone (3-NBA) is a mutagen and suspected human carcinogen detected in diesel exhaust, airborne particulate matter, and urban soil. We investigated the tissue specific mutagenicity of 3-NBA at the lacZ locus of transgenic MutaMouse following acute single dose or 28-day repeated-dose oral administration. In the acute high dose (50 mg/kg) exposure, increased lacZ mutant frequency was observed in bone marrow and colonic epithelium, but not in liver and bladder. In the repeated-dose study, a dose-dependent increase in lacZ mutant frequency was observed in bone marrow and liver (2- and 4-fold increase above control), but not in lung or intestinal epithelium. In addition, a concentration-dependent increase in mutant frequency (8.5-fold above control) was observed for MutaMouse FE1 lung epithelial cells exposed in vitro. 1-Nitropyrene reductase, 3-NBA reductase, and acetyltransferase activities were measured in a variety of MutaMouse specimens in an effort to link metabolic activation and mutagenicity. High 3-NBA nitroreductase activities were observed in lung, liver, colon and bladder, and detectable N-acetyltransferase activities were found in all tissues except bone marrow. The relatively high 3-NBA nitroreductase activity in MutaMouse tissues, as compared with those in Salmonella TA98 and TA100, suggests that 3-NBA is readily reduced and activated in vivo. High 3-NBA nitroreductase levels in liver and colon are consistent with the elevated lacZ mutant frequency values, and previously noted inductions of hepatic DNA adducts. Despite an absence of induced lacZ mutations, the highest 3-NBA reductase activity was detected in lung. Further studies are warranted, especially following inhalation or intratracheal exposures.     

Polarized Ovaries of the Long‐tongued Bat,Glossophaga soricina: A Novel Model for Studying Ovarian Development,Folliculogenesis, and Ovulation

Glossophaga soricina is a spontaneously ovulating, monovular, polyestrous bat with a simplex uterus, exhibiting true menstruation. Studies conducted on reproductively active, captive‐maintained animals established that G. soricina also has polarized ovaries, with the ovarian surface epithelium (OSE) restricted to the medial side of the ovary, and primordial follicles limited to an immediately adjacent zone. Follicles selected for further development are recruited from the medullary side of this zone, and ovulation is restricted to the portion of the ovary covered by the OSE. To further develop G. soricina as a model for studying ovarian development and physiology, ovaries were collected from fetal, neonatal, and adult females and processed for morphological and immunohistochemical analyses. The latter included staining for factor VIII‐related antigen (von Willebrand factor) to assess regional differences in ovarian vascularity. The ovarian structure in fetal and neonatal animals was very similar to that in other species that do not have polarized ovaries at comparable stages of development. This indicated that polarization of the ovary does not occur during fetal development, but rather sometime between the neonatal period and adulthood. Vascular elements were abundant in areas of the ovary surrounding early growing follicles, but sparse in the zone of the ovary containing primordial follicles. The polarized nature of the ovaries in G. soricina suggests that this species might be used as a model to investigate the formation, long‐term maintenance, and activation of primordial follicles, and the role of the OSE in ovulation and folliculogenesis. Anat Rec, 290:1439–1448, 2007. © 2007 Wiley‐Liss, Inc.     

Analysis of gene mutations and clastogenicity following short-term treatment with azathioprine in MutaMouse.

The mutagenicity and clastogenicity of the immunosuppressive drug azathioprine (AZA), a multitissue rodent carcinogen and IARC-classified human carcinogen, was investigated using transgenic lacZ mice (MutaMouse). Male animals (n = 5 per group) were dosed with AZA (10, 50, 100 mg/kg p.o. daily for 5 days), vehicle (n = 10), or the positive control, chlorambucil (15 mg/kg i.p., n = 3), and killed 24 hr or 25 days after the last treatment. Micronucleus assays were performed with bone marrow (24-hr samples) or peripheral blood (24-hr and 25-day samples) and DNA was extracted from bone marrow and liver for gene mutation analysis at the transgenic lacZ locus. AZA induced 5.3-111.3-fold increases in %MNPCE (P < 0.01) in bone marrow compared with vehicle control, accompanied by 4.4-5. 6-fold increases in %MNRETs (P < 0.01) in peripheral blood. Chlorambucil caused a 14.5-fold increase in %MNRET and there was evidence of significant stem cell toxicity in both positive control and AZA treatment groups. By day 25, however, there was evidence of substantial recovery of the bone marrow as determined by the frequency of RET, and the %MNRET in all treatment groups was the same as the vehicle control. Analysis of lacZ MF showed 1.4-1.6-fold increases in AZA 24-hr bone marrow samples, increasing to approximately 2.0-fold above concurrent controls by day 25 (medium dose P < 0.05, high dose P < 0.01). For liver, there was a 2-fold increase in MF (P < 0.05) in the 24-hr sample at the highest dose only, and increases of 1.3-1.5-fold by day 25 in the medium (P < 0. 05) and high (P = 0.055) dose groups, respectively. The positive control, chlorambucil, induced 2-3-fold increases (P < 0.01) in mean MF in both bone marrow (25-day sample) and liver (24-hr and 25-day samples). These data confirm the clastogenicity of AZA in the mouse, and show that this compound induces gene mutations in bone marrow and liver, in vivo, at the highest dose and supports the view that AZA is a genotoxic carcinogen.     

Ovarian surface epithelium during ovulatory and anovulatory ovine estrous cycles

Background: Ovarian surface epithelial cells have been implicated in the mechanisms of ovulation and development of common ovarian cancers. An early indication of predisposition to neoplasia is the formation of ovarian epithelial inclusion cysts. It was unclear whether morphological alterations along the ovarian surface are related directly to ovulation per se or associated endocrine parameters of reproductive cyclicity. Methods: Light microscopic disturbances in ovarian surface epithelium were monitored during synchronous ovulatory and anovulatory estrous cycles of sheep. Ovulation blockade accompanied by normal luteal phases was induced by administration of indomethacin, a prostaglandin synthase inhibitor. Results: Degenerative cells were sloughed from the apical dome of periovulatory follicles. The resultant stigma of luteinizing follicles was void of surface epithelium. Repair of the ovulatory wound by epithelium did not occur until complete involution of the corpus luteum during the subsequent estrous cycle. In a few cases inclusions containing entrapped ovarian surface epithelium were noted within adjacent stroma. Epithelia covering luteinized unruptured follicles remained intact and was not incorporated into the ovary during luteal resorption. Conclusion: Localized damage to and subsequent remodelling of the ovarian surface occurs in a cyclic fashion conjoined with the physical process of follicular rupture. © 1994 Wiley-Liss, Inc.     

Abandonment of germ cells in the embryonic chick ovary: TEM and SEM studies

Background: Embryonic chick ovary forms medulla and cortex successively in early developmental stages. Unlike the cortex, which is a functioning tissue in the adult, the medulla regresses as development advances. Although germ cells are included in these respective regions, their behavior within these regions is different. This study focuses on the fate of germ cells in the medulla of both ovaries. Methods: Germ cells found in the medulla of the developing chick ovary from 7 to 19 days of incubation were observed by TEM and SEM. Results: From 10 days of incubation onward, medullary germ cells in both right and left ovaries were often released into medullary lacunae. During the releasing process, germ cells were covered by thin cytoplasm of epithelial cells of the lacunae. After release, however, they were freed from the thin coat of epithelial cells. Abandoned germ cells were seen in the lacunae as solitary cells or as a mass composed of several cells. In the right ovary, germ cells released into the lacunae were subsequently found at the holes of the ovarian surface, which were continuous with the medullary lacunae. Moreover, germ cell death was often found in late stages in the medullary tissues of both right and left ovaries. Conclusions: The present study clarifies the fact that chick germ cells of the medulla of both right and left ovaries are either discarded by a process of programmed cell death and/or released into medullary lacunae with increasing embryo age. © 1994 Wiley-Liss, Inc.     

Ovarian germ cell tumor/mastocytosis with KIT mutation: A unique clinicopathological entity

Most tumors are sporadic and originated from somatic mutations. Some rare germline mutations cause familial tumors, often involving multiple tissues or organs. Tumors from somatic mosaicism during embryonic development are extremely rare. We describe here a pediatric patient who developed both an ovarian germ cell tumor and systemic mastocytosis. Targeted DNA next-generation sequencing analysis revealed similar genomic changes including the same KIT D816V mutation in both tissues, suggesting a common progenitor cancer cell. The KIT mutated cells are likely from early embryonic development during germ cell migration. A literature search found additional eight similar cases. These diseases are characterized by pediatric-onset, all-female, neoplastic proliferation in both gonad and bone marrow, and a common oncogenic cause, that is, KIT mutation, constituting a clinically and genetically homogenous disease entity. Importantly, the association of germ cell tumors with hematopoietic neoplasms suggests that the primordial germ cells are the primitive hematopoietic stem cells, a much-debated and unsettled question.     

Ovarian Histopathology of Bitches Immunized With Porcine Zonae Pellucidae

ABSTRACT: The ovarian histopathology of bitches immunized with crude (cPZP) or partially purified (pPZP) porcine zona pellucida proteins was examined in order to determine the cause of abnormal estrous cycles. The majority of immunized bitches had ovarian cytes. Those immunized with cPZP had follicular cysts lined with a thin layer of granulosa cells, while in those immunized with pPZP, the cysts were lined by a basement membrane with a clump of luteinized cells. In two bitches immunized with cPZP, oocytes were present only in primordial follicles. Similar abnormalities were not found in a bitch immunized with human serum albumin or in 12 untreated bitches. Oocytes flushed from the oviducts of mated, immunized bitches were degenerating, which may have been a primary cause of infertility in such bitches. Ovaries studied 2–6 weeks after immunization showed no loss of gap junctional communication between oocytes and granulosa cells, nor was any inflammatory reaction seen. IgG was bound to the zona as revealed by fluoresceinated protein A staining of frozen sections of those ovaries. Abnormal estrous cycles in PZP-immunized bitches appear to result from follicular dysgenesis or cyst formation, but the etiology of these conditions is unresolved.     

Ovarian morphometrics in TP53‐deficient mice

The objective of these investigations was to characterize ovarian responses to hormonal stimulation in TP53‐deficient mice. TP53‐deficient (KO) and wild‐type (WT) mice were induced to ovulate with pregnant mare serum gonadotropin followed by human chorionic gonadotropin. Effect of estradiol on ovarian morphology was determined in induced and control mice implanted with estradiol‐containing or placebo pellets. Blood was collected and mice were killed 7 days following implantation. Preserved ovaries were serially sectioned and stained. Numbers of follicles (all classifications) decreased with ovulation induction, but did not differ between WT and KO mice. Numbers of corpora lutea (CL) were less in ovulation‐induced KO mice treated with estradiol compared to WT mice. Area of individual CL and serum concentrations of progesterone were greater in ovulation‐induced KO mice given estradiol compared to WT mice. Ovulation‐induced KO mice had more, larger hemorrhagic follicles than similarly treated WT mice, but hemorrhagic follicles were not influenced by estradiol. Proliferation of ovarian surface epithelial cells did not differ between KO and WT mice induced to ovulate and given estradiol. Ovaries from TP53 gene knockout mice (n = 4) induced to ovulate and given a 21‐day estradiol implant three times over 58 days were observed for precursor lesions. There was no indication of precursor lesions in any TP53 KO or WT mouse. TP53 status did not influence recruitment of follicles, but TP53 deficiency hindered the ability of human chorionic gonadotropin to cause ovulation. Anat Rec, 290:59–64, 2007. © 2006 Wiley‐Liss, Inc.     

Effect of a partially purified 30.1 kDa ovine follicular fluid protein on ovine follicle and ovarian somatic cell growth, and oocyte maturation in vitro

Aim: Regulation of folliculogenesis and oocyte–somatic cell interactions in the ovarian follicles is under the control of gonadotrophins and various local factors. In the present study, an attempt was made to isolate and examine the biological activities of ovarian follicular fluid protein(s) in sheep in vitro. Methods: Follicular fluids aspirated from ovarian follicles of slaughterhouse‐derived ovaries were made cell free by centrifugation (5000 g for 30 min) and steroid free by charcoal treatment. The follicular fluid was then subjected to ammonium sulphate precipitation and gel filtration chromatography using G‐75 Sephadex. Protein detection was performed using a UV spectrophotometer at 280 nm. The 35–50% fraction yielded a detectable peak and a protein of 30.1 kDa as examined by SDS‐PAGE. The effect of increasing doses of the 30.1 kDa ovine follicular fluid protein (oFFP) was tested at different doses on pre‐antral and antral follicle growth; cumulus cell expansion; oocyte maturation; changes in protein, calcium and phosphorus levels of oocytes after culture in media containing different levels of isolated protein; mural granulosa cell, polar granulosa cell (cumulus cell), oviductal epithelial cell monolayer formation and granulosa cell proliferation in vitro. Results: The oFFP significantly inhibited antral follicle growth, cumulus expansion, oocyte maturation and somatic cell growth in vitro in a dose‐dependent manner. The oFFP did not have a significant effect on the pre‐antral follicle growth in vitro. The protein, calcium and phosphorus contents of oocytes were found to decrease in oocytes cultured in maturation medium containing the oFFP. Conclusion: The present study demonstrates a follicular fluid factor regulating folliculogenesis and oocyte maturation in sheep.     

The Prevalence of Autoimmune Disorders Among Patients With Primary Ovarian Failure*

ABSTRACT: Eighty-one patients who had a diagnosis of primary ovarian failure were studied to determine its possible association with autoimmune disorders. All 81 patients displayed 46, XX chromosome complements. On ovarian biopsy, either few or no follicles were demonstrated in 79 patients, and, in two patients, primordial follicles were more abundant. The two patients with a large number of primordial follicles had normal function of other endocrine organs; however, 15 of the 79 patients demonstrating few or no ovarian follicles had associated failure of other endocrine glands, and one patient had myasthenia gravis. Thirteen of these 15 patients sought treatment because of secondary amenorrhea, the age at onset ranging from 11 to 34 years. Of the 81 patients, 11 had primary amenorrhea and 70 had secondary amenorrhea. Among the 79 patients with few or no ovarian follicles, endocrine glandular failure, in addition to ovarian failure, was found in two patients with primary amenorrhea and in 13 patients with secondary amenorrhea. The association of polyglandular failure syndrome and primary ovarian failure, along with demonstration of a lymphocytic infiltrate in ovaries and circulating antibodies in sera of women with premature ovarian failure, suggests that an autoimmune mechanism may be a cause of primary ovarian failure in some cases.     

过氧化物酶体增殖物激活受体β与上皮性卵巢癌的关系

目的:探讨过氧化物酶体增殖激活物受体β(PPARβ)的表达及其与上皮性卵巢癌临床病理特征间的关系。方法:用免疫组织化学染色和半定量RT-PCR法检测PPARβ在正常卵巢组织和卵巢癌组织的表达。结果:PPARβ在上皮性卵巢癌和非癌组织均有表达,PPARβ的表达定位于细胞质中,在正常卵巢、卵巢交界性肿瘤、浆液性囊腺癌中PPARβ表达阳性率分别为20%、50%及89·1%。在浆液性囊腺癌中表达明显高于交界性肿瘤和正常卵巢组织(P<0·05),且与临床分期、组织学分级和淋巴结转移有关(P<0·05)。结论:PPARβ表达水平增高可能与卵巢上皮癌的分化转移有关。     

Biovularity and "coalescence of primary follicles" in ovaries with mature teratomas

Several theories have been postulated regarding the origin of ovarian teratomas, including incomplete twinning, neoplastic proliferation of sequestered totipotent blastomeres or primordial cells, derepression of totipotent genetic information in the nuclei of somatic cells, and parthenogenetic development of germ cells. At present parthenogenetic development of ova is the most widely accepted theory, primarily because of the presence of a 46 XX karyotype in almost all mature teratomas. However, some authors have raised the possibility of fusion of ova in the mechanism of formation of ovarian teratomas. We report the results of a study on ovarian tissue adjacent to 31 teratomas to assess the frequency of biovularity, which could provide evidence favoring the last theory. On the whole we found biovularity in 26 ovaries of young patients (mean age, 27 years) with variable numbers of biovular follicles ranging from 1 in 4 cases to more than 10 in 2 cases; the number of biovular follicles depended on the quantity of ovarian tissue examined as well as on the total number of ova in the tissue. In multiple occasions 2 ova were included within a single follicle; in 24 ovaries the biovularity was correlated with coalescence of primary follicles characterized morphologically by an ovoid or hourglass-like shape that resulted from cohesion of 2 follicles. As control cases, 30 ovaries of patients with an average age of 28 years were examined (12 removed for endometriosis, 8 for serous cystadenoma, 7 for tubal pregnancy, and 3 for acute salpingo-oophoritis). Only 1 ovary with endometriosis contained a single biovular follicle. The results suggest that ovarian teratoma development may result from fusion of ova in ovaries containing biovularity and phenomena of coalescence of primary follicles.     

Induction of lacZ mutations in Muta™Mouse primary hepatocytes

We have developed an in vitro mutation assay using primary hepatocytes from the transgenic Muta?Mouse. Primary hepatocytes were isolated using a two‐step perfusion method with purification by Percoll, cultured, and treated with benzo[a]pyrene (BaP), 2‐amino‐1‐methyl‐6‐phenyl‐ imidazo[4,5‐b]pyridine (PhIP), 3‐nitrobenzoanthrone (3‐NBA), and cigarette smoke condensate (CSC). The mean lacZ mutant frequency (MF) for the solvent control was approximately twofold greater than the spontaneous MF observed in liver tissue. A concentration‐dependent increase in MF (up to 3.7‐fold above control) was observed following exposure to BaP. Fourfold and twofold increases in mutant frequency were observed for 3‐NBA and PhIP exposures, respectively, without the addition of any exogenous metabolic activation. A slight but statistically significant increase in lacZ MF was observed for CSC, but only at the lowest concentration. This is the first report demonstrating that mutations can be detected in cultured primary hepatocytes from Muta?Mouse. The preliminary results presented suggest that the Muta?Mouse primary hepatocyte mutagenicity assay can be used as a cost‐effective tool for screening of environmental mutagens and therapeutic products. Environ. Mol. Mutagen., 2010 © 2009 Wiley‐Liss, Inc.