Do we need a new classification for radical hysterectomy? Insights in surgical anatomy and local tumor spread from human embryology

OBJECTIVE

Current surgical treatment of cervical carcinoma is based on the assumption of undirected intra- and transcervical local tumor propagation and is executed by tailored excision of the paracervical tissues. We have recently demonstrated that cervical carcinoma spreads for extended phases during its malignant progression within the permissive compartment of the Müllerian morphogenetic unit (Lancet Oncol 2005;6:751-56) and proposed Müllerian compartment resection as the new principle for surgical treatment of cervical cancer. Do we need a new classification of radical hysterectomy?

METHODS

The therapeutic index of the surgical treatment of cervical carcinoma FIGO stages IB1-IIB by extirpation of the Müllerian compartment through total mesometrial resection (TMMR) without adjuvant radiation is evaluated by an ongoing controlled prospective trial at the University of Leipzig.

RESULTS

From 7/1998 to 12/2006, 163 patients with cervical carcinoma, FIGO stages IB1 (n=94), IB2 (n=21), IIA (n=14) and IIB (n=34) have been treated with TMMR and nerve-sparing therapeutic lymph node dissection. Twenty-five patients received (neo)adjuvant chemotherapy. No patient underwent adjuvant radiotherapy although 95 patients (58%) would have needed this additional modality in case of conventional radical hysterectomy because of their high-risk histopathological tumor features. At a median follow-up time of 45 months (3-104 months), recurrence-free and disease-specific overall survival is 93% and 96%. Maximum treatment-related morbidity according to the Franco-Italian score has been grade 2 in 12 patients (8%).

CONCLUSIONS

The developmental view of local tumor spread and surgical anatomy holds a great promise for improving the therapeutic index of surgical cervical cancer therapy and challenges both the classification of radical hysterectomy based on tailored paracervical resection and the indication for adjuvant radiation.

Prenatal Development of the Bovine Oviduct

In this study the development of the bovine Fallopian tube was investigated using light microscopic methods. Formation and differentiation of the Müllerian duct were studied in mesonephroi of 16 embryos and fetuses with a crown-rump lengths (CRL) of 0.9-8.4 cm. The funnel field, the rostral beginning of the Müllerian duct was first observed at a CRL of 0.9 cm. It appears as a thickening of the mesothelium on the craniolateral side of the mesonephros. During later development the Müllerian duct emerges by caudal outgrowth from the funnel field. Formation of a common basal lamina surrounding the caudal tips of Müllerian and Wolffian ducts could be observed at all stages up to CRL of 2.7 cm. The mesothelium and the epithelium of the Wolffian duct adjacent to the Müllerian duct showed a modification of epithelium height in all examined stages. Probably the Wolffian duct influences the growth of Müllerian duct by epithelio-mesenchymal interactions. Fetuses from a CRL of 12.0 to 94.0 cm were used for investigation of the prenatal differentiation of the oviductal mucosa. Folding of the oviductal mucosa started at a CRL of 29.0 cm and continued until birth. Individual primary, secondary and tertiary folds are formed in special proliferation zones and epithelium-folding buds. The cellular differentiation of the oviductal epithelium involves the formation of ciliated and secretory cells during different times of prenatal development. Ciliogenesis was first detected at a CRL of 33.0 cm. Active secretory cells could be observed in the oviductal epithelium from a CRL of 64.0 cm onwards.

Sexually dimorphic expression of secreted frizzled-related (SFRP) genes in the developing mouse Müllerian duct

In developing male embryos, the female reproductive tract primordia (Müllerian ducts) regress due to the production of testicular anti-Müllerian hormone (AMH). Because of the association between secreted frizzled-related proteins (SFRPs) and apoptosis, their reported developmental expression patterns and the role of WNT signaling in female reproductive tract development, we examined expression of Sfrp2 and Sfrp5 during development of the Müllerian duct in male (XY) and female (XX) mouse embryos. We show that expression of both Sfrp2 and Sfrp5 is dynamic and sexually dimorphic. In addition, the male-specific expression observed for both genes prior to the onset of regression is absent in mutant male embryos that fail to undergo Müllerian duct regression. We identified ENU-induced point mutations in Sfrp5 and Sfrp2 that are predicted to severely disrupt the function of these genes. Male embryos and adults homozygous for these mutations, both individually and in combination, are viable and apparently fertile with no overt abnormalities of reproductive tract development.

Müllerian inhibiting substance regulates its receptor/SMAD signaling and causes mesenchymal transition of the coelomic epithelial cells early in Müllerian duct regression

Examination of Müllerian inhibiting substance (MIS) signaling in the rat in vivo and in vitro revealed novel developmental stage- and tissue-specific events that contributed to a window of MIS responsiveness in Müllerian duct regression. The MIS type II receptor (MISRII)-expressing cells are initially present in the coelomic epithelium of both male and female urogenital ridges, and then migrate into the mesenchyme surrounding the male Müllerian duct under the influence of MIS. Expression of the genes encoding MIS type I receptors, Alk2 and Alk3, is also spatiotemporally controlled; Alk2 expression appears earlier and increases predominantly in the coelomic epithelium, whereas Alk3expression appears later and is restricted to the mesenchyme, suggesting sequential roles in Müllerian duct regression. MIS induces expression of Alk2, Alk3 and Smad8, but downregulates Smad5 in the urogenital ridge. Alk2-specific small interfering RNA (siRNA) blocks both the transition of MISRII expression from the coelomic epithelium to the mesenchyme and Müllerian duct regression in organ culture. Müllerian duct regression can also be inhibited or accelerated by siRNA targeting Smad8 and Smad5,respectively. Thus, the early action of MIS is to initiate an epithelial-to-mesenchymal transition of MISRII-expressing cells and to specify the components of the receptor/SMAD signaling pathway by differentially regulating their expression.

Experimental contributions to the study of the embryology of the vagina

BACKGROUND

Acién's hypothesis, deduced from patients with malformations of the female genital tract, especially those with renal agenesis and ipsilateral blind hemivagina, affirms the embryology of the human vagina as deriving from the Wolffian ducts and the Müllerian tubercle and could explain the embryological origin of all the female genital malformations reported. In this study, we investigated the hypothesis in rats.

METHODS

Twenty-five pregnant rats were used to analyse female embryos (64) from day 15 (stage indifferent) to day 20 postcoitum (vagina completely formed). We performed transverse and longitudinal sections of embryos, haematoxylin-eosin tinction and immunohistochemical staining using markers specific to Wolffian derivatives. We also analysed the presence of these markers in the vagina of four adult rats.

RESULTS

The Müller ducts converge until they fuse into one tube, but caudally they diverge and finally they fuse with the 'urogenital sinus bulbs' that are actually the distal portion of the Wolffian ducts according to the immunohistochemical marking with GZ1 and GZ2. The Müllerian tubercle is observed between those elements. Then, the immunohistochemical staining can be seen all along the completely formed vagina, which is also observed in the vagina of the adult rat.

CONCLUSION

We prove the participation of Müller tubercle and Wolffian ducts in the formation of the vagina in rats, so we confirm experimentally Acién's hypothesis about the human vagina embryology.

Association between the mesenchymal compartment of uterovaginal organogenesis and local tumour spread in stage IB–IIB cervical carcinoma: a prospective study

BACKGROUND

Macroscopic, microscopic, and occult local tumour spread might be restricted to a permissive territory related to the morphogenesis of the tissue or organ from which the tumour originates. We aimed to define such a morphogenetic unit in Müllerian development, and to assess the role of total mesometrial resection in the treatment of patients with stage IB-IIB cervical carcinoma.

METHODS

We analysed uterovaginal development in serial sections of female human embryos and fetuses, and defined the distal Müllerian morphogenetic unit from the Müllerian mesenchyme. We assessed prospectively the histopathological and clinical findings from patients who underwent total mesometrial resection-modified surgery for stage IB-IIB cervical carcinoma that aims to remove the uterus, proximal vagina, and extracervical mesenchyme within the borders of the distal Müllerian morphogenetic unit.

FINDINGS

The spatial extension of the Müllerian mesenchyme, its vascularisation, and its innervation during early uterovaginal organogenesis determine a tissue territory that can be followed during fetal development and identified in women as a morphogenetic unit. 105 of 106 patients who had total mesometrial resection, 63 of whom were classed as high risk, had microscopically tumour-free resection margins (ie, R0). 48 (96%) of 50 patients had pelvic recurrence-free survival at 3 years (95% CI 92-100) without adjuvant radiotherapy.

INTERPRETATION

Radical en-bloc resection of a topographically defined anatomical territory derived from common precursor tissue leads to local tumour control, preservation of autonomic nerves, and a reduced need for adjuvant radiotherapy.

THE PROSTATIC UTRICLE IS NOT A MÜLLERIAN DUCT REMNANT: IMMUNOHISTOCHEMICAL EVIDENCE FOR A DISTINCT UROGENITAL SINUS ORIGIN

PURPOSE

The embryological origin of the utricle is thought to be a remnant of the fused caudal ends of the müllerian ducts (MDs). Others propose that the urogenital sinus (UGS) contributes either partially or totally to the development of this structure. Using immunohistochemical probes, we provide strong evidence that the utricle is of UGS origin only.

MATERIALS AND METHODS

Human fetal prostates, gestational ages 9 to 24 weeks, were serially cross-sectioned. Representative sections were stained with antibodies to p63 (basal cell marker), vimentin (mesoderm marker), uroplakins (marker for urothelium) Pax-2 (expressed in ductal and mesenchyme of urogenital system including the MDs and wolffian ducts) and Ki67 (proliferation). Apoptosis was detected with the TUNEL assay.

RESULTS

By 9 weeks there was weak expression of p63 in the basal layer of the UGS. At 11 weeks there was increased staining of p63 in the UGS and some p63 staining of the fused MDs, which expressed Pax-2 at this time. At 14 to 15 weeks as the MDs were undergoing apoptosis, there was an ingrowth of uroplakin-expressing UGS epithelium into the periurethral stroma, which formed a plate of p63 positive cells just beneath the UGS that was Ki67 positive. The remaining caudal MD epithelium was p63 negative and expressed vimentin and Pax-2. By 17 weeks the plate of p63 positive cells elongated forming the utricle that remained p63 positive but Pax-2 and vimentin negative.

CONCLUSIONS

We show that the utricle forms as an ingrowth of specialized cells from the dorsal wall of the UGS as the caudal MDs regress.

The broad ligament: A review of its anatomy and development in different species and hormonal environments

The broad ligament is a double fold of peritoneum forming a mesentery for the human female genital tract. We investigated the anatomy of the broad ligament in different species and its hormonal regulation to determine if it had a role in gonadal positioning. The medical and veterinary literature was reviewed for descriptions of broad ligament anatomy and development. In addition, four adult female rats were dissected to compare the macroscopic anatomy of the broad ligament with any homologous structures in the male (n = 2). Detailed review was made of human males with persistent Müllerian duct syndrome (PMDS) and of bovine freemartin calves to determine the effect of abnormal hormonal environments on broad ligament development. Human and veterinary texts show variable broad ligament development between species, most being consistent with the size and shape of the uterus and uterine tubes. The broad ligament in adult female rats is a simple peritoneal fold and is homologous with the mesentery of the testis and vas deferens in males. Patients with PMDS and bovine freemartins have a broad ligament with intermediate anatomy. In PMDS the broad ligament is elongated and narrow, and not attached to the pelvic wall. The broad ligament is the mesentery of the genital ducts, and its anatomy varies with the degree of Müllerian duct fusion. The absence of a human male homologue is unusual, as the genital mesentery persists in male rodents. Apparent lack of a male homologue in the human may relate to obliteration of the processus vaginalis. The variable development of the broad ligament in pathological conditions is consistent with a role for steroid hormones in its development.

Localization of Bcl-2 in the human fetal müllerian tract

OBJECTIVE

To determine if apoptosis is involved in development of the human fetal mullerian tract and regression of the uterine septum and to localize Bcl-2. a protein involved with regulating apoptosis.

DESIGN

Descriptive controlled study.

SETTING

Tertiary academic medical center.

PATIENT(S)

Eight human fetal uteri from 12 to 21 weeks' gestation.

INTERVENTION(S)

Immunohistochemistry using a monoclonal antibody for Bcl-2.

MAIN OUTCOME MEASURE(S)

Immunostaining.

RESULTS

Bcl-2 was localized in endometrial cells, tubal muscularis and epithelium, and myometrial edges. It was absent from the septum of 4 uteri.

CONCLUSIONS

The presence of Bcl-2 suggests that development of the human fetal müllerian tract involves apoptosis. Bcl-2 may protect the fetal endometrium from apoptosis as it continues to grow. The superior, inferior, and lateral myometrium as well as the tubal epithelium and muscularis also may represent active growth zones that are protected from apoptosis. The notable absence of staining for Bcl-2 in the embryonal uterine septum may indicate lack of protection from apoptosis in this area. This finding supports our hypothesis that apoptosis may be a mechanism by which the uterine septum regresses.

Androgens and masculinization of genitalia in the spotted hyaena (Crocuta crocuta). 1. Urogenital morphology and placental androgen production during fetal life

According to common understanding of sexual differentiation, the formation and development of a penile clitoris in female spotted hyaenas requires the presence of naturally circulating androgens during fetal life. The purpose of the present study was to determine potential source(s) of such fetal androgens by investigating the timing of urogenital development and placental production of androgen during early and mid-gestation. Fetuses determined to be female by molecular techniques (lack of SRY gene) at days 33 and 48 of gestation had undifferentiated gonads, but the clitoris was already 'masculinized' and was generally similar to the phallus of a 50-day-old male fetus. Wolffian and Müllerian ducts terminated at the urogenital sinus in both sexes and a urethra was present along the entire length of the clitoris and penis. The adrenal gland was large and histologically differentiated at 33 days. Steroid gradients across the uterus (a drop in delta 4-androstenedione, with increases in oestrogen and androgen), and high androstenedione in ovarian veins indicated that ovarian androstenedione was metabolized and secreted as testosterone by the placenta throughout gestation. In vitro, whole or homogenized placentae at days 48 and 58 of gestation (110 days total) metabolized radiolabelled androstenedione into testosterone and oestradiol; the specific enzymatic activity of early placental tissues was higher than at later stages. A human placental homogenate had higher aromatase activity but did not produce testosterone unless aromatase was inhibited. Infusion of labelled androstenedione into the uterine arteries of hyaenas demonstrated the conversion of this substrate into testosterone and oestradiol and their secretion into the fetal circulation. Evidently, androgen is produced by the placenta and secreted into the fetal circulation from early in pregnancy when masculinization is first evident, before differentiation of the fetal ovary.

Interactions of gonadal steroids and pesticides (DDT, DDE) on gonaduct growth in larval tiger salamanders, Ambystoma tigrinum

In view of the current worldwide decline in amphibian populations, exploratory studies are needed to assess the potential for environmental contaminants to act as endocrine disrupters of the amphibian reproductive system. The present study investigated the effects of DDT dichlorodiphenyltrichloroethane (DDT) and dichlorodiphenyldichloroethylene (DDE) on the development of amphibian gonaducts. Larval male and female tiger salamanders (Ambystoma tigrinum), with immature gonads, were immersed in a sublethal solution of p,p'-DDE or technical-grade DDT (80% p,p'-DDT and 20% o,p'-DDT). Additionally, larvae were injected with the steroid hormones estradiol or dihydrotestosterone (DHT). Morphometrics were used to analyze the effects and interactions of steroid and pesticide treatments on larval gonaducts. Estradiol and DHT stimulated cell proliferation and hypertrophy of the müllerian duct epithelium in both sexes. Wolffian duct epithelium, however, was stimulated only by DHT treatment. The pesticide DDT antagonized the estrogenic actions of the steroid treatments, and p,p'-DDE acted as an estrogen on the müllerian ducts of females only. The müllerian ducts of males, and the wolffian ducts of both sexes, were unaffected by DDT or DDE alone. While confirming the previously reported estrogenic actions of estradiol and DHT on urodelean gonaducts, the results contradict the expected estrogenic actions of DDT and antiandrogenic actions of p,p'-DDE. Instead, in A. tigrinum, technical-grade DDT had an antiestrogenic action and p,p'-DDE an estrogenic action.

Sexual differentiation of the urogenital system of the fetal and neonatal tammar wallaby, Macropus eugenii

In male tammar wallabies, the scrotum is the first organ to become sexually differentiated, 4-5 days before birth (day 22 of gestation). This is followed by enlargement of the gubernaculum and processus vaginalis one day before birth. However the indifferent gonad does not show any signs of testicular cord formation or androgen production until later, at around the time of birth; this is more pronounced at 2 days post-partum (p.p.), when the testis takes on a characteristic rounded appearance. Primordial germ cells proliferate throughout the testis at this time, although the testis does not become significantly heavier than the ovary until around 80 days p.p.. In females, the appearance of the mammary glands is the first sign of sexual differentiation 4-5 days before birth. The indifferent gonad first shows signs of developing an ovarian cortex and medulla 7 days after birth. The migrating germ cells are confined to the cortex, and first start to enter meiosis about 25 days after birth. The Wolffian (mesonephric) ducts are patent to the urogenital sinus in fetuses at day 21 of gestation. In the female they have started to regress by 10 days p.p. and only rudiments remain by day 25 p.p.. The Müllerian (paramesonephric) ducts develop adjacent to the cranial pole of the mesonephros at about day 25 of gestation and grow caudally to meet the urogenital sinus between days 2 and 7 p.p.. The Müllerian duct of the female develops a prominent ostium abdominale by day 9 p.p., but this structure has completely regressed in males by day 13 p.p.. The testis and ovary both migrate caudally, together with the adjacent mesonephros, at about day 10 p.p.. The ovaries remain around the level of lumbar vertebra 4 after about day 7 p.p., while the testes continue to descend. The testes enter the internal inguinal ring at about day 25 p.p., about the time that prostatic buds first appear in the urogenital sinus, and are in the inguinal canal from days 25 to 36 p.p.. They enter the scrotum at around day 36 p.p., and testicular descent is complete by days 65-72 p.p.. Melanin develops in the tunica vaginalis 72 days after birth. The overall development of the urogenital system in this marsupial is similar to that of eutherians but the sequence of events differs, with some aspects of genital differentiation preceding gonadal differentiation, apparently because they are directly controlled by X-linked genes, rather than indirectly controlled by gonadal steroids.

DiI analysis of cell migration during müllerian duct regression

In most male vertebrates, the müllerian ducts, which are the embryonic oviducts, regress completely during embryogenesis or shortly thereafter. Müllerian duct regression is caused by the testicular hormone müllerian inhibiting substance. While the exact mechanism of müllerian duct regression is not well understood, it is theorized to involve active migration of at least some of the ductal epithelial cells following breakdown of the basement membrane, possibly through an interaction between the epithelial cells and the surrounding extracellular matrix. The purpose of the present study was (1) to confirm that müllerian duct regression is characterized by epithelial cell migration and (2) to determine the destination of these cells. The ductal epithelium of male alligator embryos was labelled with the fluorescent cell marker DiI and then allowed to undergo regression in vitro. DiI-labeled müllerian ducts from female embryos served as controls. An in vivo experiment also was performed in which the müllerian ducts of female hatchlings were injected with DiI prior to each female receiving a testicular implant from a male hatchling. Control females received a kidney implant instead. In both the in vitro and the in vivo experiments, DiI-labeled epithelial cells were observed migrating out from the duct during regression. In the in vitro experiment in which regression proceeded more rapidly, epithelial cells entered the mesonephric kidneys and were incorporated into the nephric tubule epithelium. No regression or cell migration was observed in the control müllerian ducts.

Extended production of the müllerian duct regressor in the American alligator

Regression of the müllerian ducts in mammals and birds is caused by the testicular hormone, müllerian inhibiting substance (MIS), which is produced for an extended period of time after testicular differentiation. Because it is present long after the ducts regress, it has been proposed to have additional effects other than inducing Mullerian duct regression. A testicular substance also appears to be responsible for müllerian duct regression in the alligator based on studies in which testicular grafts from hatchling males caused regression when implanted into castrated hatchling females. In this study, the approximate ontogeny of the regressor in the alligator was investigated by implanting testicular grafts from both hatchling and yearling males into castrated female hatchlings. Histological quantification of the ducts revealed that regression in both treatment groups was not significantly different indicating that the müllerian duct regressor in the alligator is produced for at least a year after hatching and may have additional nonregressive functions in the alligator as has been proposed for mammals and birds.

[Hormones and embryogenesis of the uterine cervix]

In the absence of the T.D.F. gene, differentiation of the genital tract follows the female development with Wolffian ducts regression, elaboration of Müllerian ducts, and homologous uro-genital sinus organization. Up to week 32, the fetal ovary secretes no organizing substance and no estrogen. Even if the maternal body is heavily impregnated by estrogens from the fetal-placental unit, the estrogenic and progestogenic activity of any steroid hormones which cross the placental barrier and enter the fetal body is reduced as a result of metabolic degradation within the fetal liver. It is only from week 32 that in normal pregnancies, phenomena of estrogenic action on the uterine cervix of the fetus are seen. This consists of hyperplasia of the endo-cervical epithelium and its emergence towards the exo-cervix. The slightest addition of non-steroid synthetic estrogens administered to the mother may interfere with this hormonal environment of the fetus and result in abnormal development of Müller's tract, particularly in the cervico-vaginal zone.

A quantitative and interspecific test for biological activity of anti-mullerian hormone: the fetal ovary aromatase assay

Anti-Mullerian hormone (AMH), also known as Mullerian-inhibiting substance or factor, has previously been shown to sex-reverse the steroidogenic pattern of fetal mammalian ovaries through repression of aromatase biosynthesis. Study of the ontogeny of the response of cyclic AMP-stimulated aromatase activity of rat fetal ovaries to AMH has allowed us to develop a quantitative bioassay for the hormone. Linear responses as a function of the logarithm of AMH concentration were observed over ranges of 0.2-7.5 micrograms/ml for the bovine protein and 0.15-2 micrograms/ml for the human protein, with a maximal decrease in aromatase activity of 90% for both proteins. Under the same in vitro conditions, AMH treatment did not affect cyclic AMP-stimulated fetal rat testicular aromatase activity. Partially purified chick AMH also decreased rat ovarian aromatase activity, allowing us to use this test to study AMH ontogeny in chick gonads. Analysis of the species specificity of AMH repression of ovarian aromatase activity indicated that turtle and rat fetal ovaries responded to AMH of other vertebrate classes, whereas aromatase activity of chick embryo ovaries could be repressed only by the homospecific hormone.

Absence of sex differences in size of the genital ducts of the rat prior to embryonic day 15.5-16.0

Sexual dimorphisms of the rat brain are generally believed to be brought about by the presence of testosterone during a critical period starting at embryonic day (ED) 17/18. In contrast, sex differences of diencephalic and mesencephalic dopaminergic neurons were observed to develop in cell cultures raised from ED 14 rat brains. This was interpreted as evidence indicating that sexual differentiation of certain neural systems may occur independently of gonadal hormones. To substantiate this claim, it was felt necessary to examine the rat embryo for clues to a possible existence of sex differences in hormonal environment prior to ED 17. Morphometry was applied to compare the development of male and female Wolffian and Müllerian ducts, both primary targets of hormones secreted from the male gonad. Diameters of serially cross-sectioned Wolffian and Müllerian ducts were measured in rats of ED 15.0 to ED 16.5. Females had thicker Müllerian ducts from ED 15.5 on. The first step of differentiation in males was the widening of the lumen and a slight increase of the outer diameter of the Wolffian duct at ED 16.0. The size differences of both ducts were most obvious in the vicinity of the lower half of the gonad. Except in Wolffian ducts of ED 16.5, sex differences were absent in the caudal parts of the ducts. It appears that gonadal androgen and Müllerian inhibiting substance do not affect the development of their classical target organs prior to ED 16.0 and ED 15.5, respectively. Furthermore, the first effects are paracrine in nature. There is no evidence for sex differences in systemic androgen environment until ED 16.5.(ABSTRACT TRUNCATED AT 250 WORDS)

Origin of müllerian duct and its later developmental changes in relation to wolffian duct in bovine fetuses

At the 1.6-1.8 cm stages in both male and female bovine fetuses, the anlage of the Müllerian duct was first observed as an elevation of mesothelium on the cranial tip of the mesonephros. The duct extended toward the urogenital sinus in parallel with the Wolffian duct. Its caudal end was solid and was fused with the Wolffian duct at about the level of the middle of the gonadal anlage. Thereafter, the Müllerian duct became gradually independent of the Wolffian duct throughout its whole length. Therefore, it may be that the main part of the Müllerian duct is established by budding from the Wolffian duct. At the 4.3-4.5 cm stages the male Müllerian duct began to degenerate and the female one continued to grow. This suggests that the male Müllerian duct is affected by the Müllerian inhibiting substance at these stages. At the 12.0 cm stage, the female Wolffian duct disappeared. The male Wolffian duct was also much reduced in diameter at this stage, but began to grow again from the 14 cm stage onward.

Differentiation and development of the reproductive system in the iguanid lizard, Sceloporus undulatus

Embryos of the lizard Sceloporus undulatus were sampled throughout incubation, and the differentiation and development of the reproductive system was documented histologically. The undifferentiated gonads possess both a cortex and medulla, both of which contain germ cells until embryonic stage 34. Beginning at stage 34, the cortex of the presumptive ovary thickens, and cortical germ cells are more abundant. By the time of hatching, the ovarian cortex is 6 to 10 cells thick and filled with oogonia and oocytes; primordial follicles, however, are not yet present. In males at embryonic stage 34, seminiferous tubules appear in the medulla of the testis, and Sertoli cells begin to differentiate. Seminiferous tubule formation is complete by hatching, and both Sertoli and Leydig cells are apparent. The mullerian ducts develop in both sexes but begin regressing in the male at embryonic stage 37. The wolffian ducts also develop in both sexes and are present in males and females at hatching.

The mesonephric (wolffian) and paramesonephric (müllerian) ducts of golden hamsters express different intermediate-filament proteins during development

We analysed the expression of intermediate-filament proteins in the developing mesonephric duct (the precursor of the male genital ducts) and the paramesonephric duct (the precursor of the female genital ducts) of golden-hamster embryos using immunohistochemical methods. Embryos were investigated from the early stages of duct development, i.e. at 9.5 days post conceptionem (dpc), through sexual differentiation, until birth (15.5 dpc). Monospecific antibodies to vimentin or keratins 7, 8, 18 or 19 as well as two keratin antibodies that are pan-epithelial in human tissues were tested. Both ducts expressed vimentin to some degree from their early stages (mesonephric duct from 9.5 dpc onwards; paramesonephric duct from 10.5 dpc onwards) until birth. No keratins were detectable at these earliest stages. In the mesonephric duct, keratins 7, 18 and 19 appeared simultaneously at 10.5 dpc and persisted until birth. In the paramesonephric duct, only keratin 18 was detectable at first (at 12.0 dpc), with the expression of keratins 7 and 19 being delayed until 14.5 dpc. This feature was irrespective of sexual differentiation, which begins at 11.0 dpc, so that, in males, these keratins appeared on cue, even though the paramesonephric duct was regressing at this time. The expression of keratin 8 could not be demonstrated in either duct using the antibodies tested in our study. By 14.5 dpc, the differentiated male mesonephric duct and the differentiated female paramesonephric duct exhibited the same intermediate-filament protein pattern (weak vimentin expression and strong expression of keratins 7, 18 and 19), in spite of differences in the intermediate-filament protein patterns exhibited by the two ducts during early development. These different programmes of intermediate-filament protein regulation do not support the concept that the mesonephric duct makes a cellular contribution to the paramesonephric duct during the development of the latter.

Absence of anti-Müllerian activity of inhibin in the chick embryo

Inhibin extracted from bovine follicular fluid and administered to chick embryos at a dosage increasing from 0.4 to 30 micrograms per embryo did not induce the regression of the Müllerian ducts of treated females. This result contrasts with that obtained with a testis graft which acts through its anti-Müllerian hormone. Although both hormones were of glycoproteic nature and secreted by the same cells, this study shows no functional analogy between them.

Secretion of the anti-müllerian hormone by the gonads of experimentally sex reversed female chick embryos

The gonads of genetically female chick embryos experimentally transformed into testes under the influence of a embryonic testis graft are able to induce in vivo the regression of Müllerian ducts when they are grafted to female embryonic hosts. On the other hand female gonads only transformed into ovotestes are ineffective on the host MDs, as in the case for female gonads. These results show that totally sex reversed gonads have the same properties as a normal testis. In particular they produce the anti-Müllerian hormone, whereas partially reversed gonads do not or only do at a very low level.

The vagina is formed by downgrowth of Wolffian and Müllerian ducts. Graphical reconstructions from normal and Tfm mouse embryos

We use the Tfm (testicular feminization) mutation of the mouse to reexamine the role of Wolffian and Müllerian ducts during formation of the vagina. Three dimensional graphical reconstructions of the lower genital tract are prepared from serial sections of male, female, and Tfm embryos from day 15 p.c. until 8 days after birth. The reconstructions show that in female and Tfm animals the caudal segments of Wolffian and Müllerian ducts fuse and migrate caudally, whereas in the male they do not fuse and remain in their original position. Following down-growth, separate Wolffian and Müllerian ducts emerge from the fused caudal tips of the ducts. The Wolffian ducts degenerate, while the Müllerian ducts fuse with each other and form the vagina. Wolffian and Müllerian ducts are connected to the urogenital sinus by the sinus ridges which in later stages are separated from the sinus by lateral furrows. The sinus ridges are replaced by the Müllerian ducts. We conclude that the vagina develops by down-growth of Wolffian and Müllerian ducts along the sinus ridges. Wolffian ducts and sinus ridges regress so that the definitive vagina is formed by the Müllerian ducts. In Tfm embryos the vagina forms as in the female but subsequently degenerates, probably due to the action of AMH. The vaginal pocket in the Tfm is the variable remainder of the vagina at the end of the degeneration process.

Morphological studies on the role of the periductal stroma in the regression of the human male Müllerian duct

The regression of the male Müllerian duct has been studied in human embryos and fetuses by means of the semi-thin light microscopic technique and by electron microscopy. After completion of the duct's differentiation during week 7, a periductal stroma is formed by two types of mesenchymal-like cells: light, epitheloid cells originating from the coelomic epithelium and dark, fusiform cells of mesonephric origin. During week 9 these cells condense to a compact cuff in which the light cells occupy the inner core. The duct is entirely sealed by an epitheloid stratum of the periductal stroma. At the same time, the basal lamina thickens up to 300 nm by apposition of extracellular material. During weeks 10 to 12, the inner stromal core is invaded by dark fusiform cells from the peripheral stratum which intermingle with the light cells. The basal lamina dissolves, the epithelio-stromal interface becomes indistinct and finally disappears. During week 13 remnants of the Müllerian duct can be observed. They result from the complete merging of the ductal into the periductal compartment. Müllerian duct regression is divided into two functional steps: First the duct is prevented from growth by the epitheloid cells of the stromal cuff. This process lasts for 2 to 3 weeks. In the second place the basal lamina breaks up under the influence of the dark stromal component. This event launches the regression proper and lasts for another 2 to 3 weeks. Necrosis of cells or programmed cell death does not play a decisive role in the regression of the human Müllerian duct. In the upper, nonregressing part of the duct, light epitheloid cells are scarce and do not seal the duct. A periductal extracellular space is preserved during the entire period and the periductal stroma does not fuse with the duct's epithelium. The epithelio-stromal interface is maintained along this section.

Improved histology for the chick-quail chimera

A simple modification of nuclear staining after acid hydrolysis has been made which provides easy identification of quail nuclear markings in a chick-quail chimera. This method also improves the histologic detail normally seen with hematoxylin and eosin when compared to the more commonly used Feulgen reaction. Embryonic tissues can be fixed in Zenker's or Helly's solution and the sections obtained are hydrolyzed in acid (3.5 N HCl at 37 C for 40-50 min). After acid hydrolysis the sections are stained with hematoxylin and eosin rather than Schiff reagent and fast green. The interphase nuclei of chick cells show homogeneous or mottled purplish blue staining, while quail nuclei contain a dark blue spot. This staining corresponds to the reddish purple staining of the quail's heterochromatin seen adjacent to the nucleolus in the standard Feulgen stain. This new technique facilitates identification of quail cell types in the chick host and provides superior histology of the chick tissues by demonstrating cytoplasmic detail.

Production of Monoclonal Antibodies for Affinity Purification of Bovine Mullerian Inhibiting Substance Activity

Two monoclonal antibodies (IG8 and IG10) specific for Mullerian inhibiting substance (MIS) were obtained from the fusion between myeloma cell line SP2/0 and spleen cells from an A/J mouse immunized with partially purified MIS. The resulting hybridomas were screened by a solid-phase RIA and two lines were selected and cloned. Both MAbs IG8 and IG10 subsequently demonstrated specificity for MIS by their ability to inhibit biologically active MIS by precipitation with a second antibody, directly block MIS activity in the organ culture assay, and adsorb and elute active MIS when coupled to a solid support. SDS-polyacrylamide gel electrophoresis of affinity purified MIS demonstrated a major band at 140 kD in unreduced gels and two bands with approximate molecular weights of 70 and 74 KD following reduction. Protein bands were localized either directly by silver staining or on immunoblots developed with radiolabeled anti-MIS MA.

Is Mullerian-inhibiting substance a circulating hormone in the chick-quail chimera?

Mullerian-inhibiting substance (MIS) is a glycoprotein from the fetal testis which causes regression of the embryonic Mullerian duct. It was thought to be a locally acting agent, because in the true hermaphrodite, a Fallopian tube remains on the side contralateral to that bearing a testis, but is absent on the side adjacent to the testis. To test whether Mullerian duct regression could occur at a distant site, the chick-quail chimera was used. Chick embryos were maintained in shell-less culture from 3-14 days of incubation. At 7-9 days of incubation, a chick/quail chimera was created by grafting a quail Mullerian duct into the eye of the chick. Three or four days later, the eye was enucleated and histologically examined using the Feulgen reaction or a modification of this technique. Under these conditions, the quail cell nuclei could be readily identified, allowing absolute identification of the cells around the graft. Twenty-three female chick hosts received grafts; of the 17 grafts recovered, 16 were developing normally. In 16 male chicks receiving grafts, 10 Mullerian ducts were recovered, with 9 of these showing clear signs of regression, such as basement membrane dissolution, condensation of mesenchyme, diminution of epithelial tube size, and thinning of mesenchymal cuff. These results suggest that MIS reached the quail duct in the eye and was functionally active. This model suggests that MIS may be a true endocrine testicular secretion.

Action of testis graft from puromycin- or cAMP-pretreated donor embryos on the regression of Müllerian ducts in the female chick embryo

Female chick embryos grafted with a piece of embryonic testis manifest in a high percentage of cases a regression of their Müllerian ducts (MD) under the influence of a anti-Müllerian hormone (AMH) secreted by the graft. Puromycine or cAMP administered to grafted females reduced significantly the percentage of those presenting a MD regression. In the present work puromycin or cAMP was administered to the male graft-donor embryos and not to the grafted females as was done previously. A testis graft from a puromycin-pretreated donor was significantly less active on the MD than that from a normal embryo. It could be then concluded that puromycin acted at the level of the testis by inhibiting the AMH production. On the other hand, the treatment of donors with cAMP did not modify their testes with regard to their action on the grafted female MD. This showed that cAMP directly protected the MD against the AMH.

The role of the Wolffian ducts in the formation of the sinus vagina: an organ culture study

In mammals formation of a sinus vagina is inhibited in the male by endogenous testosterone from the embryonic testes. To answer the question which morphogenetic events during formation of the vagina are influenced by testosterone, we explanted genital tracts of mouse embryos in the indifferent stage of development in organ culture. Half of the explants were treated with testosterone and therefore developed in male direction. The other half was kept without testosterone and developed constitutively in female direction. Since the anti Müller factor was not present, in both types of cultures the Müllerian ducts were preserved. During female development the Müllerian ducts fused with the dorsolaterally apposed caudal segments of the Wolffian ducts. Thus the caudal segments of the Wolffian ducts were incorporated in the vaginal plate, while cranially the Wolffian ducts degenerated as expected. During male development fusion between Müllerian and Wolffian ducts did not occur. Under the influence of testosterone the respective caudal segments of the Wolffian ducts were surrounded by dense mesenchyme and further male differentiation took place. We conclude that the 'sinus protrusions' or 'sinovaginal bulbs' observed during development of the vagina, are in fact the caudal segments of the Wolffian ducts. They serve as a link between Müllerian ducts and urogenital sinus. Formation of a sinus vagina is prevented by testosterone simply by induction of male development in this area.

Enhanced purification of Mullerian inhibiting substance by lectin affinity chromatography

Mullerian inhibiting substance (MIS), a secreted testicular product responsible for regression of the Mullerian ducts in the male mammalian embryo, was purified 7000 fold, exploiting the glycoprotein nature of this important fetal regressor to achieve enhanced purification. The present procedure employs media incubation of newborn calf testis, passage through DEAE Bio-Gel A and CM Bio-Gel A and sequential lectin affinity chromatography on wheat germ lectin (WGL)-Sepharose 6MB and concanavalin A (Con A)-Sepharose 4B. Strongly bioactive MIS was released from both lectin columns in the bound glycoprotein fraction only after elution with lectin-specific sugar. Carbohydrate analysis of the highly purified glycoprotein fraction eluted from Con A indicated the presence of both N-acetyl glucosamine and mannose, as would be expected from its sequential lectin affinity, as well as of galactose, galactosamine and N-acetyl neuraminic acid. Electrophoresis of this fraction on polyacrylamide-SDS gels showed an identical band pattern after staining with either Coomassie blue or periodic acid-Schiff reagent, further indicating that MIS is a glycoprotein.

Sonographic characteristics of congenital uterine abnormalities and associated pregnancy

Faulty development of the mullerian duct system results in various uterine, vaginal, and renal abnormalities. Complete or partial absence of mullerian duct fusion and/or canalization results in septate, bicornuate, or double uterus; the specific anomaly depends upon the degree of fusion and canalization. Unilateral renal agenesis is frequently associated. Three cases of uterine anomalies associated with pregnancy are presented. When a pregnancy occurs in one side of a double uterus, the nonpregnant side may simulate a solid pelvic mass, such as a leiomyoma. In anomalies where there is a communication between two uterine cavities, the nonpregnant side may require the appearance of a cystic mass. Pregnancy associated with uterine anomalies carries significant morbidity.

Involution of the female Mullerian duct of the fetal rat in the organ-culture assay for the detection of Mullerian Inhibiting Substance

The study of Mullerian Inhibiting Substance (MIS) has been made possible because of the organ-culture bioassay devised by Picon ('69) for detecting MIS in vitro. We have studied the degeneration of the female Mullerian duct of the rat fetus, the target tissue of the assay, with electron microscopy. We have observed that the involution of the female Mullerian duct in the organ-culture assay follows a pattern of degeneration similar to the normal involution of the male Mullerian duct under the influence of MIS from the fetal testis (Price et al., '77). This involution involves alterations in the duct epithelium subsequent to a response of the mesenchyme surrounding the duct. The degeneration of a specific organ system under the direct influence of a specific factor, Mullerian Inhibiting Substance, represents an example of "programmed cell death."

Complete and partial vaginal agenesis

The proper diagnosis and treatment of a patient with vaginal agenesis demands a thorough knowledge of the relevant embryology, anatomy and physiology as well as sensitivity to the potentially emotionally devastating effects of the condition. Ten patients with vaginal agenesis were evaluated and treated at Wilford Hall USAF Medical Center over a three-year period. The patients fell into three groups, those with: (1) Müllerian atresia, complete or partial; (2) maldevelopment of the lower one-third of the vagina; and (3) testicular ferminization. Other congenital anomalies existed in many of these patients. Most of the patients were treated with the Frank method of vaginal development with good results. Some underwent surgical correction.

Clear cell carcinoma of the uterine endocervix with an in situ component

In the past all clear cell carcinomas of the female genital tract were thought to arise from mesonephric remnants. Recently increasing evidence has related their origin to müllerian rather than mesonephric epithelium. One of the main reasons that has been advanced to support their mesonephric origin has been their occurrence in the uterine cervix and vagina, sites of mesonephric remnants. However, no clear evidence for mesonephric origin of clear cell carcinoma of the cervix and vagina has been ever provided. In contrast, there is substantial evidence that diethylstilbestrol-related clear cell carcinomas of the cervix and vagina are müllerian in origin. We report here a case of an exophytic clear cell carcinoma with an in situ component, involving the endocervical epithelium. The in situ lesion clearly indicates müllerian origin of the tumor, which occurred in the absence of prenatal exposure to diethylstilbestrol. This supports the general agreement that clear cell carcinomas of the cervix are müllerian in origin, whether diethylstilbestrol-related or not.

Pseudohermaphroditis, with testes and a 46, XX karyotype

A 14 4/12-year-old white girl, evaluated for progressive virilization and clitormegaly, was found to have the unusual combination of a 46, XX karyotype, well-developed Mullerian structures, and dysgenetic testes with Leydig cell hyperplasia. Although there have been previous case reports of 46, XX males, in all of these patients development of the Mullerian ducts had been suppressed. When contemporary classifications of human disorders of sexual differentation were reviewed, no report of a similar patient was found. We speculate that the genotype and phenotype in our patient correspond to the genetic intersexuality of the hornless goat, thereby raising the possibility that the human autosome may play a role in the control of sexual development.

Practitioners'--breeders' approach to canine parturition

Both veterinary surgeon and dog breeder should be involved in assessing the whelping capability of brood bitches as one essential point in the selection of sound stock. Normal parturition is described in a manner that might be used in the instruction of breeders and nursing auxiliaries in midwifery. In its classical three stages, the mechanics and hydraulics are explained in simple terms and the hormonal changes discussed in relation to each stage. The type of co-operation desired between veterinary surgeon and breeder is discussed and the instruction to be given on the recognition of dystocia is outlined. Some commonly met dystocias are described. Simple digitally-assisted delivery by the midwife/breeder is described as are the forceps techniques which may be applied by the veterinary surgeon in the course of diagnosis and delivery.