Effect of intravenous vitamin C on arterial blood gas analyser and Accu-Chek point-of-care glucose monitoring in critically ill patients.

Background: Intravenous vitamin C is known to interfere with some point-of-care blood glucose meters. We aimed to determine the concentrations at which ascorbate interferes with glucose concentrations measured using a point-of-care blood glucose meter. We also compared the point-of-care meter and an arterial blood gas (ABG) analyser in the intensive care unit with laboratory glucose monitoring in septic patients receiving intravenous vitamin C infusions. Methods: Blood samples containing normal, depleted and supplemented glucose and increasing concentrations of ascorbate (0.1-1.0 mmol/L) were tested using an Accu-Chek Inform II (Roche Diagnostics, USA) glucometer. For the in vivo study, 41 individual blood samples were drawn daily from septic patients (n = 16) receiving infusions of 25 mg/kg of vitamin C every 6 hours. The glucose values of matched blood samples were assessed using Accu-Chek, ABG and laboratory glucose methods. Results: For every 1 mmol/L of ascorbate added, the glucose concentration measured by the point-of-care monitor increased by 1.4 mmol/L (95% CI, 1.0-1.8; P < 0.001). Analysis of matched blood samples collected following intravenous vitamin C infusion indicated that 98% of the ABG and 83% of the Accu-Chek values met the International Organization for Standardization (ISO) 15197:2013 accuracy criteria. One patient had severe renal impairment, which contributed to elevated plasma vitamin C concentrations (median, 0.95 mmol/L; range, 0.64-1.10 mmol/L), resulting in elevated Accu-Chek readings and presenting a moderate clinical risk for the highest value. Conclusions: Vitamin C concentrations < 0.8 mmol/L do not interfere with point-of-care glucose monitoring. Intravenous vitamin C infusion of 25 mg/kg every 6 hours does not interfere with point-of-care glucose monitoring unless the patient has renal impairment, in which case laboratory glucose tests should be used.

Instant messaging apps and data protection: combining to improve hip fracture care?

INTRODUCTION: The General Data Protection Regulation (GDPR) continues to have implications for how healthcare information is managed and shared. This presents challenges as telemedicine plays a more central role in service healthcare service provision, particularly since the beginning of 2020. We aim to measure how improved communication through a GDPR-compliant messaging app can influence time-dependent key performance indicators for hip fracture management in a tertiary-referral trauma hospital. METHODS: Using an instant messaging service, a hip fracture group was created and access was provided to all stakeholders in hip fracture care-trainee and consultant emergency physicians and orthopaedic surgeons, as well as advanced nurse practitioners, bed managers, ward managers and theatre managers. Irish Hip Fracture Database (IHFD) standard compliance was compared from April to December 2017 and April to December 2018. RESULTS: Two periods in 2017 and 2018 saw 121 and 122 hip fracture patients admitted, respectively. Mean time to admission to an orthopaedic ward in 2017 was 47 ± 42.9 h and 33.3 ± 42 h in 2018 (P = 0.5). Mean time to surgery in 2017 was 83.66 ± 53.46 h and 39.11 ± 10.84 h in 2018 (p = 0.026). CONCLUSIONS: Irish Hip Fracture Database Standards present a challenge to orthopaedic departments competing with other hospital specialties for access to beds and theatre space. The introduction of a GDPR-compliant social media messaging service has contributed to significantly reducing the time to surgery for these patients. Streamlining communication through messaging services has and continues to be vital to improving care for hip fracture patients, both in the healthcare environment and beyond.

Hip fracture care during Covid-19: a regional trauma centre's experience.

INTRODUCTION: The Covid-19 pandemic has caused worldwide upheaval from early 2020. Trauma and orthopaedic services are no different. A fundamentally important and significant portion of trauma services is the treatment of fragility fractures of the proximal femur, otherwise known as hip fractures. The hip fracture "Blue book Standards", the key performance indicators (KPIs) associated with appropriate hip fracture care are challenging during non-crisis times. We aim to review Blue Book compliance during the Covid-19 crisis and review outcomes of hip fractures, including Covid-19 infection rates. METHODS: We retrospectively reviewed IHFD data to collection demographic data, IHFD standards of care, 30-day mortality rates and complications between 23rd March and 20th May 2020 and 2019. Covid-19 rates in 2020 were also recorded. RESULTS: A total of 36 hip fractures were recorded in 2020, compared with 45 in 2019, resulting in a 20% reduction in presentations. Thirty-day mortality in hip fractures during the Covid-19 crisis was 8.3% compared with 2.2% in 2020. Covid-19 infection was statistically associated with 30-day mortality in the 2020 cohort. Statistically significant improvements in time-dependent KPIs (time to ward and time to surgery) were noted in the 2020 cohort. CONCLUSIONS: Despite improvements in hip fracture care KPIs, the Covid-19 crisis was associated with increased 30-day mortality in hip fracture patients. A positive Covid-19 swab was associated with higher mortality. These observations are of paramount importance to ensure adequate service planning and provision in the face of a potential "second wave" of Covid-19 infections leading into the winter months of 2020.

Effects of androgen and oestrogen on IGF pathways controlling phallus growth.

The development of the mammalian phallus involves hormone-dependent mesenchymal-epithelial signalling mechanisms that contribute to urethral closure and regulation of phallus elongation and growth. In marsupials, most differentiation and growth of the phallus occurs post-natally, making them amenable to direct hormone treatment. Expression of IGFs, FGFs, EFNB2, MAFB, DLX5 and AP-1 mRNAs in the phallus at day 50 post-partum (pp) were altered after treatment of tammar wallaby young from day 20 to 40 pp with androgen, oestrogen or after castration at day 25 pp. However, the most interesting changes occurred in the IGF pathway genes. Androgen treatment upregulated IGF1 in female phalluses and oestrogen treatment upregulated IGF1 in male phalluses, but it was downregulated by castration. IGFBP3 was higher in female phalluses and downregulated by androgen. IGF1 expression was higher in all untreated male than in female phalluses from day 50 to 150 pp, but IGFBP3 had the reverse pattern. At day 90 pp, when urethral closure in males is progressing and male phallus growth is accelerating. IGF1 and PCNA protein were only detected in the male urorectal septum, suggesting for the first time that closure and elongation may involve IGF1 activation of cell proliferation specifically in male phalluses. These effects of sex steroids on gene expression and on the IGF1 signalling pathway in particular, suggest that the developing phallus may be especially susceptible to perturbation by exogenous hormones.

Transcriptomic Analysis of MAP3K1 and MAP3K4 in the Developing Marsupial Gonad.

MAPKs affect gonadal differentiation in mice and humans, but whether this applies to all mammals is as yet unknown. Thus, we investigated MAPK expression during gonadal differentiation and after treatment with oestrogen in a distantly related mammal, the marsupial tammar wallaby, using our model of oestrogen-induced gonadal sex reversal. High-throughput RNA-sequencing was carried out on gonads collected from developing tammar 2 days before birth to 8 days after birth to characterise MAPK and key sexual differentiation markers. Day 25 foetal testes were cultured for 120 h in control medium or medium supplemented with exogenous oestrogen and processed for RNA-seq to identify changes in gene expression in response to oestrogen. MAPK pathway genes in the tammar were highly conserved at the sequence and amino acid level with those of mice and humans. Marsupial MAP3K1 and MAP3K4 clustered together in a separate branch from eutherian mammals. There was a marked decrease in the expression of male-determining genes SOX9 and AMH and increase in the female marker FOXL2 in oestrogen-treated male gonads. Only MAP3K1 expression increased in male gonads in response to oestrogen while other MAPK genes remained unaffected. This study suggests that MAP3K1 can be influenced by exogenous oestrogens during gonadal differentiation in this marsupial.

Too frail for surgery? A frailty index in major colorectal surgery.

BACKGROUND: Frailty is defined as increased vulnerability from accumulating morbidities in multiple organ systems. Evidence suggests frailty indices predict surgical outcomes in elderly patients. We assessed the validity of a frailty index in predicting post-operative outcomes in major colorectal surgery. METHODS: A retrospective review of a prospective database was studied. Patients aged less than 65 years were excluded. Patients were assessed using a validated National Surgical Quality Improvement Program frailty index. Endpoints included intensive care unit (ICU) stay, post-operative complications and 30-day post-operative mortality, and also compared using American Society of Anesthesiologists (ASA) grade and P-Possum CR. RESULTS: Of the 205 patients, 43 (21%) were frail and 162 (79%) were not frail. Seven percent of frail patients required ICU stay compared with 6% non-frail patients (P > 0.05, NS). P-Possum in frail versus non-frail groups in ICU was 48% versus 8.6% (P < 0.05). Forty percent of frail and 26% non-frail patients developed post-operative complications (P > 0.05, NS) with mean P-Possum of 23% versus 12% in these groups, respectively (P < 0.05). Five percent of frail patients and 2.5% non-frail patients died within 30 days of surgery (P > 0.05, NS) with a mean P-Possum of 43% versus 7% in these groups, respectively (P > 0.05, NS). CONCLUSIONS: These data demonstrate that frail patients who developed complications, died within 30 days and required admission to ICU had significantly higher P-Possum CR scores. However, the P-Possum CR score is a superior predictor of post-operative outcomes than frailty index alone.

Hormone-responsive genes in the SHH and WNT/ß-catenin signaling pathways influence urethral closure and phallus growth.

Environmental endocrine disruptors (EEDs) that affect androgen or estrogen activity may disrupt gene regulation during phallus development to cause hypospadias or a masculinized clitoris. We treated developing male tammar wallabies with estrogen and females with androgen from day 20-40 postpartum (pp) during the androgen imprinting window of sensitivity. Estrogen inhibited phallus elongation but had no effect on urethral closure and did not significantly depress testicular androgen synthesis. Androgen treatment in females did not promote phallus elongation but initiated urethral closure. Phalluses were collected for transcriptome sequencing at day 50 pp when they first become sexually dimorphic to examine changes in two signaling pathways, sonic hedgehog (SHH) and wingless-type MMTV integration site family (WNT)/ß-catenin. SHH mRNA and ß-catenin were predominantly expressed in the urethral epithelium in the tammar phallus, as in eutherian mammals. Estrogen treatment and castration of males induced an upregulation of SHH, while androgen treatment downregulated SHH. These effects appear to be direct since we detected putative estrogen receptor α (ERα) and androgen receptor (AR) binding sites near SHH. WNT5A, like SHH, was downregulated by androgen, while WNT4 was upregulated in female phalluses after androgen treatment. After estrogen treatment, WIF1 and WNT7A were both downregulated in male phalluses. After castration, WNT9A was upregulated. These results suggest that SHH and WNT pathways are regulated by both estrogen and androgen to direct the proliferation and elongation of the phallus during differentiation. Their response to exogenous hormones makes these genes potential targets of EEDs in the etiology of abnormal phallus development including hypospadias.

Expression of STRA8 is conserved in therian mammals but expression of CYP26B1 differs between marsupials and mice.

The first sign of mammalian germ cell sexual differentiation is the initiation of meiosis in females and of mitotic arrest in males. In the mouse, retinoic acid induces ovarian Stra8 expression and entry of germ cells into meiosis. In developing mouse testes, cytochrome P450 family 26, subfamily b, polypeptide 1 (CYP26B1) produced by the Sertoli cells degrades retinoic acid, preventing Stimulated by Retinoic Acid Gene 8 (Stra8), expression and inhibiting meiosis. However, in developing humans, there is no evidence that CYP26B1 acts a meiosis-inhibiting factor. We therefore examined aspects of the retinoic acid/STRA8/CYP26B1 pathway during gonadal development in the tammar wallaby, a marsupial, to understand whether retinoic acid stimulation of STRA8 and CYP26B1 degradation of retinoic acid was conserved between widely divergent mammals. In tammar ovaries, as in human ovaries and unlike the pattern in mice, CYP26B1 expression was not downregulated before the onset of meiosis. Exposure of pre-meiotic tammar ovaries to exogenous retinoic acid in vitro upregulated STRA8 expression compared to controls. We conclude that retinoic acid and STRA8 are conserved factors that control the initiation of meiosis amongst mammals but the role of CYP26B1 as a meiosis-inhibiting factor may be specific to rodents. The identity of the marsupial meiosis-inhibiting factor remains unknown.

Uterine molecular changes for non-invasive embryonic attachment in the marsupials Macropus eugenii (Macropodidae) and Trichosurus vulpecula (Phalangeridae).

Pregnancy in mammals requires remodeling of the uterus to become receptive to the implanting embryo. Remarkably similar morphological changes to the uterine epithelium occur in both eutherian and marsupial mammals, irrespective of placental type. Nevertheless, molecular differences in uterine remodeling indicate that the marsupial uterus employs maternal defences, including molecular reinforcement of the uterine epithelium, to regulate embryonic invasion. Non-invasive (epitheliochorial) embryonic attachment in marsupials likely evolved secondarily from invasive attachment, so uterine defences in these species may prevent embryonic invasion. We tested this hypothesis by identifying localization patterns of Talin, a key basal anchoring molecule, in the uterine epithelium during pregnancy in the tammar wallaby (Macropus eugenii; Macropodidae) and the brush tail possum (Trichosurus vulpecula; Phalangeridae). Embryonic attachment is non-invasive in both species, yet Talin undergoes a clear distributional change during pregnancy in M. eugenii, including recruitment to the base of the uterine epithelium just before attachment, that closely resembles that of invasive implantation in the marsupial species Sminthopsis crassicaudata. Basal localization occurs throughout pregnancy in T. vulpecula, although, as for M. eugenii, this pattern is most specific prior to attachment. Such molecular reinforcement of the uterine epithelium for non-invasive embryonic attachment in marsupials supports the hypothesis that less-invasive and non-invasive embryonic attachment in marsupials may have evolved via accrual of maternal defences. Recruitment of basal molecules, including Talin, to the uterine epithelium may have played a key role in this transition.

Uterine flushing proteome of the tammar wallaby after reactivation from diapause.

The marsupial tammar wallaby has the longest period of embryonic diapause of any mammal, up to 11 months, during which there is no cell division or blastocyst growth. Since the blastocyst in diapause is surrounded by acellular coats, the signals that maintain or terminate diapause involve factors that reside in uterine secretions. The nature of such factors remains to be resolved. In this study, uterine flushings (UFs) were used to assess changes in uterine secretions of tammars using liquid chromatography-mass spectrometry (LC-MS/MS) during diapause (day 0 and 3) and reactivation days (d) 4, 5, 6, 8, 9, 11 and 24 after removal of pouch young (RPY), which initiates embryonic development. This study supports earlier suggestions that the presence of specific factors stimulate reactivation, early embryonic growth and cell proliferation. A mitogen, hepatoma-derived growth factor and soluble epidermal growth factor receptors were observed from d3 until at least d11 RPY when these secreted proteins constituted 21% of the UF proteome. Binding of these factors to specific cellular receptors or growth factors may directly stimulate DNA synthesis and division in endometrial gland cells. Proteins involved in the p53/CDKN1A (p21) cell cycle inhibition pathway were also observed in the diapause samples. Progesterone and most of the oestrogen-regulated proteins were present in the UF after d3, which is concomitant with the start of blastocyst mitoses at d4. We propose that once the p21 inhibition of the cell cycle is lost, growth factors including HDGF and EGFR are responsible for reactivation of the diapausing blastocyst via the uterine secretions.

Embryo-endometrial interactions during early development after embryonic diapause in the marsupial tammar wallaby.

The marsupial tammar wallaby has the longest period of embryonic diapause of any mammal. Reproduction in the tammar is seasonal, regulated by photoperiod and also lactation. Reactivation is triggered by falling daylength after the austral summer solstice in December. Young are born late January and commence a 9-10-month lactation. Females mate immediately after birth. The resulting conceptus develops over 6- 7 days to form a unilaminar blastocyst of 80-100 cells and enters lactationally, and later seasonally, controlled diapause. The proximate endocrine signal for reactivation is an increase in progesterone which alters uterine secretions. Since the diapausing blastocyst is surrounded by the zona and 2 other acellular coats, the mucoid layer and shell coat, the uterine signals that maintain or terminate diapause must involve soluble factors in the secretions rather than any direct cellular interaction between uterus and embryo. Our studies suggest involvement of a number of cytokines in the regulation of diapause in tammars. The endometrium secretes platelet activating factor (PAF) and leukaemia inhibitory factor, which increase after reactivation. Receptors for PAF are low on the blastocyst during diapause but are upregulated at reactivation. Conversely, there is endometrial expression of the muscle segment homeobox gene MSX2 throughout diapause, but it is rapidly downregulated at reactivation. These patterns are consistent with those observed in diapausing mice and mink after reactivation, despite the very different patterns of endocrine control of diapause in these 3 divergent species. These common patterns suggest a similar underlying mechanism for diapause, perhaps common to all mammals, but which is activated in only a few.

Paf receptor expression in the marsupial embryo and endometrium during embryonic diapause.

The control of reactivation from embryonic diapause in the tammar wallaby (Macropus eugenii) involves sequential activation of the corpus luteum, secretion of progesterone that stimulates endometrial secretion and subsequent changes in the uterine environment that activate the embryo. However, the precise signals between the endometrium and the blastocyst are currently unknown. In eutherians, both the phospholipid Paf and its receptor, platelet-activating factor receptor (PTAFR), are present in the embryo and the endometrium. In the tammar, endometrial Paf release in vitro increases around the time of the early progesterone pulse that occurs around the time of reactivation, but whether Paf can reactivate the blastocyst is unknown. We cloned and characterised the expression of PTAFR in the tammar embryo and endometrium at entry into embryonic diapause, during its maintenance and after reactivation. Tammar PTAFR sequence and protein were highly conserved with mammalian orthologues. In the endometrium, PTAFR was expressed at a constant level in the glandular epithelium across all stages and in the luminal epithelium during both diapause and reactivation. Thus, the presence of the receptor appears not to be a limiting factor for Paf actions in the endometrium. However, the low levels of PTAFR in the embryo during diapause, together with its up-regulation and subsequent internalisation at reactivation, supports earlier results suggesting that endometrial Paf could be involved in reactivation of the tammar blastocyst from embryonic diapause.

Identification of a novel PNMA-MS1 gene in marsupials suggests the LTR retrotransposon-derived PNMA genes evolved differently in marsupials and eutherians.

Two major gene families derived from Ty3/Gypsy long terminal repeat (LTR) retrotransposons were recently identified in mammals. The sushi-ichi retrotransposon homologue (SIRH) family comprises 12 genes: 11 in eutherians including Peg10 and Peg11/Rtl1 that have essential roles in the eutherian placenta and 1 that is marsupial specific. Fifteen and 12 genes were reported in the second gene family, para-neoplastic antigen MA (PNMA), in humans and mice, respectively, although their biological functions and evolutionary history remain largely unknown. Here, we identified two novel candidate PNMA genes, PNMA-MS1 and -MS2 in marsupials. Like all eutherian-specific PNMA genes, they exhibit the highest homology to a Gypsy12_DR (DR, Danio rerio) Gag protein. PNMA-MS1 is conserved in both Australian and South American marsupial species, the tammar wallaby and grey short-tailed opossum. However, no PNMA-MS1 orthologue was found in eutherians, monotremes or non-mammalian vertebrates. PNMA-MS1 was expressed in the ovary, mammary gland and brain during development and growth in the tammar, suggesting that PNMA-MS1 may have acquired a marsupial-specific function. However, PNMA-MS2 seems to be a pseudogene. The absence of marsupial orthologues of eutherian PNMA genes suggests that the retrotransposition events of the Gypsy12_DR-related retrotransposons that gave rise to the PNMA family occurred after the divergence of marsupials and eutherians.

Ultrasonography of wallaby prenatal development shows that the climb to the pouch begins in utero.

Marsupials have a functional placenta for a shorter period of time compared to that of eutherian species, and their altricial young reach the teats without any help from the mother. We have monitored the short intrauterine development of one marsupial, the tammar wallaby, with high-resolution ultrasound from reactivation of the 100-cell diapausing blastocyst to birth. The expanding blastocyst could be visualized when it had reached a diameter of 1.5 mm. From at least halfway through pregnancy, there are strong undulating movements of the endometrium that massage the expanding vesicle against the highly secretory endometrial surface. These unique movements possibly enhance exchange of uterine secretions and gases between the mother and embryo. There was a constant rate of development measured ultrasonographically from mid-gestation, regardless of when the blastocyst reactivated. Interestingly climbing movements by the fetus began in utero about 3 days before birth, mimicking those required to climb to the pouch.

Kallmann syndrome 1 gene is expressed in the marsupial gonad.

Kallmann syndrome is characterized by hypogonadotrophic hypogonadism and anosmia. The syndrome can be caused by mutations in several genes, but the X-linked form is caused by mutation in the Kallmann syndrome 1 (KAL1). KAL1 plays a critical role in gonadotropin-releasing hormone (GnRH) neuronal migration that is essential for the normal development of the hypothalamic-pituitary-gonadal axis. Interestingly, KAL1 appears to be missing from the rodent X, and no orthologue has been detected as yet. We investigated KAL1 during development and in adults of an Australian marsupial, the tammar wallaby, Macropus eugenii. Marsupial KAL1 maps to an autosome within a group of genes that was added as a block to the X chromosome in eutherian evolution. KAL1 expression was widespread in embryonic and adult tissues. In the adult testis, tammar KAL1 mRNA and protein were detected in the germ cells at specific stages of differentiation. In the adult testis, the protein encoded by KAL1, anosmin-1, was restricted to the round spermatids and elongated spermatids. In the adult ovary, anosmin-1 was not only detected in the oocytes but was also localized in the granulosa cells throughout folliculogenesis. This is the first examination of KAL1 mRNA and protein localization in adult mammalian gonads. The protein localization suggests that KAL1 participates in gametogenesis not only through the development of the hypothalamic-pituitary-gonadal axis by activation of GnRH neuronal migration, but also directly within the gonads themselves. Because KAL1 is autosomal in marsupials but is X-linked in eutherians, its conserved involvement in gametogenesis supports the hypothesis that reproduction-related genes were actively recruited to the eutherian X chromosome.

A novel MSMB-related microprotein in the postovulatory egg coats of marsupials.

BACKGROUND: Early marsupial conceptuses differ markedly from those of eutherian mammals, especially during cleavage and early blastocyst stages of development. Additionally, in marsupials the zona pellucida is surrounded by two acellular layers, the mucoid coat and shell, which are formed from secretions from the reproductive tract. RESULTS: We report the identification of a novel postovulatory coat component in marsupials, which we call uterinesecreted microprotein (USM). USM belongs to a family of disulfide-rich microproteins of unconfirmed function that is found throughout deuterostomes and in some protostomes, and includes ß-microseminoprotein (MSMB) and prostate-associated microseminoprotein (MSMP). We describe the evolution of this family in detail, including USM-related sequences in other vertebrates. The orthologue of USM in the tammar wallaby, USM1, is expressed by the endometrium with a dynamic temporal profile, possibly under the control of progesterone. CONCLUSIONS: USM appears to have evolved in a mammalian ancestor specifically as a component of the postovulatory coats. By analogy with the known properties of MSMB, it may have roles in regulating sperm motility/survival or in the immune system. However, its C-terminal domain is greatly truncated compared with MSMB, suggesting a divergent function.

Oestrogen blocks the nuclear entry of SOX9 in the developing gonad of a marsupial mammal.

BACKGROUND: Hormones are critical for early gonadal development in nonmammalian vertebrates, and oestrogen is required for normal ovarian development. In contrast, mammals determine sex by the presence or absence of the SRY gene, and hormones are not thought to play a role in early gonadal development. Despite an XY sex-determining system in marsupial mammals, exposure to oestrogen can override SRY and induce ovarian development of XY gonads if administered early enough. Here we assess the effect of exogenous oestrogen on the molecular pathways of mammalian gonadal development. RESULTS: We examined the expression of key testicular (SRY, SOX9, AMH and FGF9) and ovarian (WNT4, RSPO1, FOXL2 and FST) markers during gonadal development in the marsupial tammar wallaby (Macropus eugenii) and used these data to determine the effect of oestrogen exposure on gonadal fate. During normal development, we observed male specific upregulation of AMH and SOX9 as in the mouse and human testis, but this upregulation was initiated before the peak in SRY expression and 4 days before testicular cord formation. Similarly, key genes for ovarian development in mouse and human were also upregulated during ovarian differentiation in the tammar. In particular, there was early sexually dimorphic expression of FOXL2 and WNT4, suggesting that these genes are key regulators of ovarian development in all therian mammals. We next examined the effect of exogenous oestrogen on the development of the mammalian XY gonad. Despite the presence of SRY, exogenous oestrogen blocked the key male transcription factor SOX9 from entering the nuclei of male somatic cells, preventing activation of the testicular pathway and permitting upregulation of key female genes, resulting in ovarian development of the XY gonad. CONCLUSIONS: We have uncovered a mechanism by which oestrogen can regulate gonadal development through the nucleocytoplasmic shuttling of SOX9. This may represent an underlying ancestral mechanism by which oestrogen promotes ovarian development in the gonads of nonmammalian vertebrates. Furthermore, oestrogen may retain this function in adult female mammals to maintain granulosa cell fate in the differentiated ovary by suppressing nuclear translocation of the SOX9 protein. See commentary: http://www.biomedcentral.com/1741-7007/8/110.