Introducing ethanol ablation as a treatment for thyroid cysts in the emergency setting

BACKGROUND

Ethanol ablation for the treatment of thyroid cysts has been well documented in the literature as a safe, effective treatment option in the elective setting. This study demonstrates the use of ethanol ablation in the emergency setting.

METHODS

Three patients presenting with airway-threatening compressive symptoms secondary to a thyroid cyst were treated with ethanol ablation within 24 hours of presentation to hospital.

RESULTS

All patients had symptom resolution at a median of nine months follow up post procedure. Sixty-six per cent of patients required only one treatment. There was a median of 100 per cent radiological resolution of the cystic component. The median Glasgow Benefit Inventory score was +27.7, similar to that for tonsillectomy.

CONCLUSION

Ethanol ablation is a safe, cost-effective and efficient treatment option for thyroid cysts in the acute setting.

Accuracy of the Pisiform Boost Test for the Diagnosis of Triangular Fibrocartilage Complex Tears in the Wrist - Pisiform Boost Test

Background

A retrospective study was conducted to evaluate the diagnostic accuracy of a novel examination technique, the 'Pisiform Boost Test,' in diagnosing a triangular fibrocartilage complex (TFCC) tear.

Methods

Wrist arthroscopies performed between 2011-2021 were retrospectively reviewed. Patients' clinical records were evaluated to determine the result of the Pisiform Boost Test during clinical examination and TFCC tear within the body of the TFCC as seen at wrist arthroscopy. The Pisiform Boost Test is performed by first assessing for ulna fovea pain on passive ulna deviation of the wrist and then assessing pain while the clinician applies digital pressure over the pisiform and passive ulna deviation.

Results

The pisiform Boost test was found to have a Sensitivity of 91% (95% CI, 81 - 97%) and a Specificity of 33% (95% CI, 14-59%) for the diagnosis of TFCC tears. Positive predictive value of 83%, a negative predictive value of 50%, and an accuracy of 78%. A chi-square test of independence was performed to examine the relation between a Positive Pisiform Boost Test and an arthroscopy-confirmed TFCC tear. The relation between these two variables was statistically significant, x2 (1, N = 82) = 6.4551, p=.011064.

Conclusion

The Pisiform Boost Test demonstrates high sensitivity for TFCC tears (0.91). Specificity (0.33) is similar to that in the ulnar grinding test. Therefore, we propose this test be utilized with additional special tests for ulna-side wrist pain to allow clinicians to build a diagnostic picture, aiding decision-making and patient information.

863 Improving the Outcomes of Inpatient Admissions and Optimising Referrals to a Regional Burns Unit Through Introduction of a Specialist Nurse-Led Burns Clinic

Aim

We aimed to measure the effect of a specialist nurse-led clinic and referral pathway on admission rate, patient length of stay (LOS), and total bed days. We hypothesised that this intervention would contribute to the optimisation of the patient pathway in a regional burn's unit.

Method

Retrospective analysis of inpatient records in a six-month period over three years at a regional burn's unit (June-November 2018,2019,2020). Analysis of demographics, TBSA, admissions, and length of stay before and after clinic introduction. Statistical analysis included one-way ANOVA.

Results

A reduction in admissions was observed in 2020 compared to 2019 and 2018 (7.3% and 6.7%) for a patient group with equivalent median TBSA (2%) and comparable median age (41 vs. 43.5 and 42.5). Median LOS was significantly shortened compared to 2019 (42.9%, F=4.07, p=0.046) and 2018 (42.9%, F=6.59, p=0.011). Minor burns showed reduced admission rates compared to 2019 (8.5%), and reduced median LOS (42.9% and 33.3%), and reduced total bed days (29.4% and 27.1%) compared to 2019 and 2018 respectively. Referrals to the regional burn's unit as a percentage total of regional A&E burns presentations increased in 2020 compared to 2019 and 2018 (16% vs. 14.4% and 12.1%).

Conclusions

The results suggest that the introduction of a specialist clinic has shortened in-patient stay with a significant effect on minor burns, against a backdrop of increased referrals. We suggest that continuity between clinic and inpatient care by a specialist nursing team has helped to optimise the regional burns unit.

Introducing Ethanol Ablation as a treatment for thyroid cysts in the emergency setting

Introduction

New techniques have been adopted for minimally invasive management of thyroid lesions which has been well explored by Nixon et al. Ethanol ablation (EA) for the treatment of thyroid cysts has been well documented in the literature as a safe, effective treatment option in the elective setting. Our unit has introduced this service in the elective setting for treatment of thyroid cysts. This study demonstrates the use of EA in the emergency setting, which has potential to reduce recurrence rates and avoid a general anaesthetic in patients who present acutely.

Methods

Three patients presenting with airway threatening compressive symptoms secondary to thyroid cysts. Treated with EA within 24 hours of presentation to hospital. Patients were followed up radiologically and clinically and a telephone consultation to gather the GBI (Glasgow Benefit Inventory) survey.

Results

2 patients female and 1 male, median age of 41 years old. Median Pre-ablation cyst volume was 97.3mls. Median 100% radiological resolution of cystic component. 100% resolution of symptoms at median 9-month follow-up post procedure. 66% of patients requiring only one treatment for 100% resolution, with 1 patient with the largest cyst requiring three ablations and two aspirations. No complications reported. GBI (Glasgow Benefit Inventory) score mean +27.7, similar GBI of a tonsillectomy.

Discussion

EA is a safe, cost effective and efficient treatment option for thyroid cysts in the acute setting. Larger thyroids cysts may require repeated procedures for symptom resolution. Patient will require long term follow up to assess the rate of recurrence.

Potential for Machine Learning in Burn Care

INTRODUCTION

Burn-related injuries are a leading cause of morbidity across the globe. Accurate assessment and treatment have been demonstrated to reduce the morbidity and mortality. This essay explores the forms of artificial intelligence to be implemented the field of burns management to optimise the care we deliver in the National Health Service (NHS) in the UK.

METHODS

Machine Learning methods which predict or classify are explored. This includes linear and logistic regression, artificial neural networks, deep learning, and decision tree analysis.

DISCUSSION

Utilizing Machine Learning in burns care holds potential from prevention, burns assessment, predicting mortality and critical care monitoring to healing time. Establishing a regional or national Machine Learning group would be the first step towards the development of these essential technologies.

CONCLUSION

The implementation of machine learning technologies will require buy-in from the NHS health boards, with significant implications with cost of investment, implementation, employment of machine learning teams and provision of training to medical professionals.

Improving the working environment for the delivery of safe surgical care in the UK: a qualitative cross-sectional analysis

OBJECTIVES

The aim of this study was to identify current problems and potential solutions to improve the working environment for the delivery of safe surgical care in the UK.

DESIGN

Prospective, questionnaire-based cross-sectional study.

SETTING/PARTICIPANTS

Following validation, an electronic questionnaire was distributed to postgraduate local education and training board distribution lists, the Royal College of Surgeons of Edinburgh (RCSEd) mailing lists and trainee organisations. This consisted of a single open-ended question inviting five open-ended responses. Throughout the 13-week study period, the survey was also published on a number of social media platforms.

RESULTS

A total of 505 responders completed the survey, of which 35% were consultants, 30% foundation doctors, 17% specialty trainees, 11% specialty doctors, 5% core trainees and <1% surgical nurse practitioners. A total of 2238 free-text answers detailed specific actions to improve the working environment. These responses were individually coded and then grouped into nine categories (staff resources, non-staff resources, support, working conditions, communication and team work, systems improvement, patient centred, training and education, and miscellaneous).

CONCLUSIONS

The results of this study have identified a number of key areas that, if addressed, may improve the environment for the delivery of safer surgical care. Common themes that emerged across all grades included: increased front-line staff; a return to a 'firm' structure to improve team continuity; greater senior support; and improved hospital facilities to help staff rest and recuperate. While unlimited funding remains unrealistic, many of the suggestions could be implemented in a cost-neutral fashion and include insightful ideas for remodelling or restructuring the workforce to improve the efficiency of the surgical team. The findings of this study formed the basis of a set of recommendations published by the RCSEd as a discussion paper.

Role of genetic testing in arrhythmogenic right ventricular cardiomyopathy/dysplasia

In a cohort of patients with confirmed or suspected arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D), genetic testing is useful in confirming the diagnosis, particularly in individuals who do not completely fulfil Task Force criteria for the disease, thereby also enabling the adoption of preventive measures in family members. Due to the high percentage of novel mutations that are expected to be identified in ARVC/D, the use of genetic screening technology based on the identification of known mutations seems to have very restricted value. Our results support that the presence of certain genetic variations could play a role in the final phenotype of patients with ARVC/D, where single and compound mutation carriers would have more symptomatic forms of the disease and the polymorphism P366L could be associated to a more benign phenotype.

414. The contraceptive potential of a long-acting IL-11 inhibitor

Interleukin 11 (IL-11) signalling is essential for the establishment of pregnancy in mice, through its action on the differentiation of uterine endometrial stromal cells (decidualisation), a critical process during embryo implantation. IL-11Rα deficient mice are infertile due to defective decidualisation1. IL-11 expression peaks between days (D) 4.5–9.5 of pregnancy (D0: day of plug) in mouse decidua. We examined the effect of administering (intraperitoneal [IP] injection or vaginal gel) a PEGylated IL-11 antagonist (PEGIL-11A) on decidualisation and pregnancy outcome in mice. The sera half-life of PEGIL-11A (IC50 2.8nM) following IP injection was 24h, compared with <1 h for the non-PEGylated antagonist (IC50 0.26nM). Following IP injection, PEGIL-11A localised to decidual cells and blocked the IL-11 decidual target protein, cyclin D3. IP injection of 600µg/application PEGIL-11A (or PEG control) at 1000 h and 1600 h on D3 and 1000 h on D4 (n = 4/group), resulted in smaller implantation sites than controls on D6 due to retarded mesometrial decidual formation. On D10, severe decidual destruction was visible: implantation sites contained regions of haemorrhage and the uterine luminal epithelium had reformed, suggesting a return to oestrous cycling. Following vaginal application in aqueous placebo gel, PEGIL-11A localised to decidual cells. Vaginal application of 200µg/application PEGIL-11A (or control) twice daily from D2 to D5 (n = 4/group), resulted in smaller implantation sites than controls on D6 due to partial inhibition of mesometrial decidual formation. This study demonstrates that PEGIL-11A blocked IL-11 action in the uterus, resulting in total pregnancy loss, equivalent to the IL-11Rα deficient mouse. In women, IL-11 and its receptor are produced by the uterine luminal and glandular epithelium during the period of uterine receptivity2, suggesting that IL-11 may act during initial blastocyst attachment to the luminal epithelium as well as stromal decidualisation. This study provides proof-of-principle for the development of a novel, non-hormonal contraceptive for women. (1) Robb L et al. Nature Medicine 1998; 4: 303–308. (2) Dimitriadis E et al. Molecular Human Reproduction 2000; 6: 907–914.

Augmented gp130-mediated cytokine signalling accompanies human gastric cancer progression

H. pylori infection accounts for most cases of gastric cancer, but the initiating events remain unclear. The principal H. pylori pathogenicity-associated CagA protein disrupts intracellular SHP-2 signalling pathways including those used by the IL-6 family cytokines, IL-6 and IL-11. Imbalanced IL-6 family cytokine signalling in the gp130(757FF) mouse model of gastric cancer arising from hyperactivation of oncogenic STAT3 after altered SHP-2 : ERK1/2 signalling produces dysplastic antral tumours preceded by gastritis and metaplasia. In a cohort of patient gastric biopsies with known H. pylori and CagA status, we investigated whether (i) STAT3 and ERK1/2 activation is altered in H. pylori-dependent gastritis; (ii) these profiles are more pronounced in CagA+ H. pylori infection; and (iii) the expression of pro-inflammatory cytokines that activate STAT3 and ERK 1/2 pathways is associated with progression to gastric cancer. IL-6, IL-11, and activated STAT3 and ERK1/2 were quantified in antral biopsies from gastritic stomach, metaplastic tissue, and resected gastric cancer tissues. We observed significantly increased STAT3 and ERK1/2 activation (p = 0.001) in H. pylori-dependent gastritis, which was further enhanced in the presence of CagA+ H. pylori strains. Of known gastric ligands that drive STAT3 activation, IL-6 expression was increased after H. pylori infection and both IL-6 and IL-11 were strongly up-regulated in the gastric cancer biopsies. This suggests a mechanism by which IL-11 drives STAT3 activation and proliferation during gastric cancer progression. We addressed this using an in vitro approach, demonstrating that recombinant human IL-11 activates STAT3 and concomitantly increases proliferation of MKN28 gastric epithelial cells. In summary, we show increased STAT3 and ERK1/2 activation in H. pylori-dependent gastritis that is likely driven in an IL-6-dependent fashion. IL-11 expression is associated with adenocarcinoma development, but not gastritic lesions, and we identify a novel mechanism for IL-11 as a potent inducer of proliferation in the human gastric cancer setting.

Effects of different regions of the developing gut on the migration of enteric neural crest-derived cells: A role for Sema3A, but not Sema3F

The enteric nervous system arises from vagal (caudal hindbrain) and sacral level neural crest-derived cells that migrate into and along the developing gut. Data from previous studies have suggested that (i) there may be gradients along the gut that induce the caudally directed migration of vagal enteric neural precursors (ENPs), (ii) exposure to the caecum might alter the migratory ability of vagal ENPs and (iii) Sema3A might regulate the entry into the hindgut of ENPs derived from sacral neural crest. Using co-cultures we show that there is no detectable gradient of chemoattractive molecules along the pre-caecal gut that specifically promotes the caudally directed migration of vagal ENPs, although vagal ENPs migrate faster caudally than rostrally along explants of hindgut. Exposure to the caecum did not alter the rate at which ENPs colonized explants of hindgut, but it did alter the ability of ENPs to colonize the midgut. The co-cultures also revealed that there is localized expression of a repulsive cue in the distal hindgut, which might delay the entry of sacral ENPs. We show that Sema3A is expressed by the hindgut mesenchyme and its receptor, neuropilin-1, is expressed by migrating ENPs. Furthermore, there is premature entry of sacral ENPs and extrinsic axons into the distal hindgut of fetal mice lacking Sema3A. These data show that Sema3A expressed by the distal hindgut regulates the entry of sacral ENPs and extrinsic axons into the hindgut. ENPs did not express neuropilin-2 and there was no detectable change in the timetable by which ENPs colonize the gut in mice lacking neuropilin-2.

015.Disrupted decidualisation in SOCS3 gene mutant mice

Cytokines comprise a large family of secreted glycoproteins that regulate many fundamental biological processes. Cytokine signals are relayed to target cells via binding to cell surface receptors. The receptors signal via members of the Janus kinases (JAKs) and signal transduction and activators of transcription family (STATs). The SOCS proteins negatively regulate cytokine signalling by inhibiting components of the JAK/STAT pathway. Genetically modified mice in which individual SOCS genes are ablated have revealed key biological roles for these proteins. SOCS3 null mice die at mid gestation due to placental insufficiency. By embryonic Day (E) 9.5 there is a marked decrease in the spongiotrophoblast layer and an increase in trophoblast giant cells in SOCS3 null placentae. With increasing gestational age, there is progressive disorganisation of the SOCS3 null placental labyrinth. Takahashi et al. (1) used tetraploid aggregation to demonstrate that the placental defect was attributable to intrinsic defects in the SOCS3-deficient trophoblast cells or yolk sac endoderm. Based on evidence from in vitro assays, SOCS3 has a role in downstream negative regulation of signalling via a large number of cytokines. To identify the cytokine responsible for the placental phenotype, we crossed SOCS3 null embryos with mice lacking leukaemia inhibitory factor (LIF). This rescued the placental phenotype of the SOCS3 null mice, thereby demonstrating that alterations in LIF signalling are responsible for profound abnormalities of the murine placenta. (1) Takahashi et al. (2003) EMBO J. 22, 372–384.

IL-11 and IL-11Ralpha immunolocalisation at primate implantation sites supports a role for IL-11 in placentation and fetal development

Embryo implantation, endometrial stromal cell decidualization and formation of a functional placenta are critical processes in the establishment and maintenance of pregnancy. Interleukin (IL)-11 signalling is essential for adequate decidualization in the mouse uterus and IL-11 promotes decidualization in the human. IL-11 action is mediated via binding to the specific IL-11 receptor alpha (IL-11Ralpha). The present study examined immunoreactive IL-11 and IL-11Ralpha in cycling rhesus monkey endometrium, at implantation sites in cynomolgus and rhesus monkeys and in human first trimester decidua and defined distinct spatial and temporal patterns. In cycling rhesus monkey endometrium, IL-11 and IL-11Ralpha increased in both basalis and functionalis regions during the secretory compared with the proliferative phase, with changing cellular locations in luminal and glandular epithelium and stroma. The patterns were similar overall to those previously described in human endometrium. Differences were seen in immunostaining during implantation in cynomologus and rhesus monkey. In the cynomolgus, very little staining for IL-11 or IL-11Ralpha was seen in syncytio- and cyto-trophoblast cells in the villi between days 12 and 150 of pregnancy although there was moderate staining in cytotrophoblast in the shell between days 12 and 17 and in subpopulations of cytotrophoblast cells invading the arteries at day 17. By contrast in the rhesus monkey between days 24 and 35 of pregnancy and in human first trimester placenta, cyto- and syncytio-trophoblast in the villi but not cytotrophoblast in the shell were positively stained. The most intense staining for both IL-11 and IL-11Ralpha was present within the decidua in the maternal component of implantation sites in all three primates but moderate staining was also present in maternal vascular smooth muscle and glands perivascular cells and epithelial plaques. These results are consistent with a role for IL-11 both during decidualization and placentation in primates.

Expression pattern of the stem cell leukaemia gene in the CNS of the embryonic and adult mouse

The basic helix-loop-helix (bHLH) transcription factor stem cell leukaemia (SCL) is a 'master regulator' of haematopoiesis, where SCL is pivotal in cell fate determination and differentiation. SCL has also been detected in CNS, where other members of the bHLH-family have been shown to be indispensable for neuronal development; however, no detailed expression pattern of SCL has so far been described. We have generated a map of SCL expression in the embryonic and adult mouse brain based on histochemical analysis of LacZ reporter gene expression in sequential sections of brain tissue derived from SCL-LacZ knockin mice. The expression of LacZ was confirmed to reflect SCL expression by in situ hybridisation. LacZ expression was found in a range of different diencephalic, mesencephalic and metencephalic brain nuclei in adult CNS. Co-localisation of LacZ with the neuronal marker NeuN indicated expression in post-mitotic neurons in adulthood. LacZ expression by neurons was confirmed in tissue culture analysis. The nature of the pretectal, midbrain and hindbrain regions expressing LacZ suggest that SCL in adult CNS is potentially involved in processing of visual, auditory and pain related information. During embryogenesis, LacZ expression was similarly confined to thalamus, midbrain and hindbrain. LacZ staining was also evident in parts of the intermediate and marginal zone of the aqueduct and ventricular zone of the fourth ventricle at E12.5 and E14. These cells may represent progenitor stages of differentiating neural cells. Given the presence of SCL in both the developing brain and in post-mitotic neurons, it seems likely that the function of SCL in neuronal differentiation may differ from its function in maintaining the differentiated state of the mature neuron.

Interleukin 11 advances progesterone-induced decidualization of human endometrial stromal cells

Differentiation of endometrial stromal cells into decidual cells is crucial for embryo implantation and placentation. Interleukin (IL)-11 signalling is essential for adequate decidualization in the mouse uterus. We examined the role of IL-11 during progesterone-induced decidualization of human endometrial stromal cells over a 10-12 day period, using prolactin (PRL) production as a decidual marker. These cells produced biologically active IL-11 and expressed IL-11, IL-11Ralpha and PRL mRNA during decidualization. Neutralization of endogenous IL-11 with an anti-human (hu)IL-11 antibody (AB) reduced production of PRL from day 8 and insulin-like growth factor binding protein (IGFBP)-1, another marker of decidualization, from day 10 of culture. Following AB washout, PRL and IGFBP-1 secretion increased. Addition of recombinant (r)huIL-11 (10 or 100 ng/ml) to endometrial stromal cells increased secretion of PRL from day 4 and IGFBP-1 from day 6 compared with progesterone alone. Morphological signs of differentiation accompanied biochemical differentiation in the progesterone-treated cells and were further induced by exogenous rhuIL-11. Our observations demonstrate that human endometrial stromal cells produce biologically active IL-11, which promotes progesterone-induced decidualization. These results suggest that IL-11 has both paracrine and autocrine actions on human endometrial stromal cells and plays an important role in preparing the human endometrium for implantation.

Genes involved in implantation

The endometrium is normally a hostile environment for an embryo, except for a short phase in each reproductive cycle known as the 'window of receptivity'. The precise molecular events involved in this transformation are not well understood. Application of state-of-the-art techniques of the 1990s has identified some of the genes involved, which are reviewed here. Mice with a null mutation in either the gene for leukemia inhibitory factor or the interleukin-11 receptor alpha chain are infertile, owing in both cases to a failure of embryo implantation. Both of these genes are expressed in the human endometrium with patterns suggesting a role in human fertility. The technique of RNA differential display has been applied to a comparison of the expression of genes at implantation sites v. inter-implantation sites in the mouse uterus on the first day of implantation, and has defined additional genes whose products may be important for this process. Among these are the calcium-binding protein D9K, the monoclonal non-specific suppressor factor beta, and the splicing factor SC35. The major challenge is to determine whether manipulation of such genes can increase or decrease endometrial receptivity in humans.

Molecular characterisation of mouse and human TSSC6: evidence that TSSC6 is a genuine member of the tetraspanin superfamily and is expressed specifically in haematopoietic organs

Previous analyses of the murine and human TSSC6 (also known as Phemx) proteins were not carried out using the full length sequence. Using 5'-RACE and cDNA library screening, we identified an additional 5' sequence for both the murine Tssc6 cDNA and its human homologue TSSC6. This novel sequence encodes a 5' exon encoding an in frame, upstream start codon, an N-terminal cytoplasmic domain and a transmembrane domain. The deduced, and now full length, murine and human TSSC6 proteins contained four hydrophobic regions together with other features characteristic of the tetraspanin superfamily. Computational analyses of the full length sequences show that TSSC6 is a genuine, albeit relatively divergent member of this superfamily. Using RNA from a number of mouse tissues, we identified seven splice variants of Tssc6. Splice variants of the human gene were also detected. Tssc6 expression was detected early in embryogenesis in primitive blood cells and was confined to haematopoietic organs in the adult mouse. Tssc6 expression was detected in many haematopoietic cell lines and was highest in cell lines of the erythroid lineage.

Cloning of rat interleukin 11 and interleukin 11 receptor alpha chain and analysis of their expression in rat uterus in the peri-implantation period

Studies in mice have shown that interleukin 11 (IL-11) signalling is required for female fertility. In the absence of IL-11, decidualization is markedly retarded and implantation fails. IL-11 acts via a heterodimeric receptor composed of a ligand-specific receptor alpha chain (IL-11R alpha) and the signalling moiety gp130. This study reports the cloning of genes encoding rat IL-11 and IL-11R alpha. RNase protection was used to demonstrate that expression of IL-11 is upregulated in the rat uterus at the initiation of implantation at 5.5 days after mating. Expression of the genes encoding the two receptor components, IL11Ra and gp130, did not change throughout the peri-implantation period. In situ hybridization studies revealed that, as in mice, expression of IL-11 was high in the primary decidual zone at the time of the attachment reaction, whereas IL11Ra was expressed throughout primary and secondary decidua. Conservation of the temporal and spatial expression of IL-11 and IL-11R alpha in the uterus of the mouse and rat during the peri-implantation period will facilitate future studies investigating the role of IL-11 in fertility.

Placental defects and embryonic lethality in mice lacking suppressor of cytokine signaling 3

Mice lacking suppressor of cytokine signaling 3 (SOCS3) exhibited embryonic lethality with death occurring between days 11 and 13 of gestation. At this stage, SOCS3(-/-) embryos were slightly smaller than wild type but appeared otherwise normal, and histological analysis failed to detect any anatomical abnormalities responsible for the lethal phenotype. Rather, in all SOCS3(-/-) embryos examined, defects were evident in placental development that would account for their developmental arrest and death. The placental spongiotrophoblast layer was significantly reduced and accompanied by increased numbers of giant trophoblast cells. Delayed branching of the chorioallantois was evident, and, although embryonic blood vessels were present in the labyrinthine layer of SOCS3(-/-) placentas, the network of embryonic vessels and maternal sinuses was poorly developed. Yolk sac erythropoiesis was normal, and, although the SOCS3(-/-) fetal liver was small at day 12.5 of gestation (E12.5), normal frequencies of erythroblasts and hematopoietic progenitor cells, including blast forming unit-erythroid (BFU-E) and, colony forming unit-erythroid (CFU-E) were present at both E11.5 and E12.5. Colony formation for both BFU-E and CFU-E from SOCS3(-/-) mice displayed wild-type quantitative responsiveness to erythropoietin (EPO), in the presence or absence of IL-3 or stem cell factor (SCF). These data suggest that SOCS3 is required for placental development but dispensable for normal hematopoiesis in the mouse embryo.

Cytokines in implantation

The endometrium of most species is now recognized as an important site of production of cytokines and their receptors. The cellular origin of the cytokines varies but many predominate in the uterine glandular or luminal epithelium or in the decidualized stromal cells. From studies in genetically modified mice it is clear that implantation of the blastocyst can proceed in the absence of most individual cytokines, although leukemia inhibitory factor and interleukin-11 have indisputable roles in this process. In other cases, such as CSF-1, GM-CSF, IL-1, and IL-6, the numbers of implantation sites or litter sizes are reduced when the cytokine is absent. The same cytokines that are implicated in implantation in mice are generally maximally expressed in human endometrium with maximal production in the secretory phase, particularly during the "window of implantation," but functional studies of their role in implantation in women and other primates are still required.

The role of IL-II in hematopoiesis as revealed by a targeted mutation of its receptor

Interleukin 11 (IL-11) is a pleiotropic growth factor with several actions in common with members of the IL-6 family. IL-11 utilizes a specific receptor chain encoded by two genes, IL-11Ra, which is expressed in hematopoietic and other tissues and, IL-11Ra2, which has a restricted pattern of expression. The actions of IL-11 in the hematopoietic compartment include support of multilineage and committed progenitors contributing to myeloid, erythroid, megakaryocyte, and lymphoid lineages. IL-11 demonstrates a prominent thrombopoietic activity which is being evaluated in clinical trials. In contrast to the multiple in vitro and in vivo effects of IL-11, mice with a targeted mutation of the IL-11Ra gene (IL-11Ra-/-) did not exhibit an overt hematological phenotype. Generation of a null phenotype was confirmed by independent assays. The numbers of progenitor cells of various lineages as well as their terminally differentiated progeny were undisturbed in the IL-11Ra-/- mice. In addition, the mutant mice were able to respond appropriately to increased demand in situations of hematopoietic stress. This study has highlighted the growth factor redundancy operative in the hematopoietic compartment, and in addition, has served to identify a critical action of IL-11 in nonhematopoietic organs.

Thrombopoietin signaling is required for in vivo expansion of IL-11--responsive hematopoietic progenitor cells in the steady state

OBJECTIVE

mpl(-/-) mice have a profound defect in platelets and megakaryocytes and a defect in hematopoietic progenitor cells and stem cells. However, no specific subset of the progenitor/stem cell compartment has been shown to be particularly affected by this deficiency in mpl(-/-) mice. In this article, we identified a specific subset of bone marrow progenitor/stem cells that was altered in mpl(-/-) mice.

MATERIALS AND METHODS

In vitro and in vivo hematopoietic assays were utilized to examine the response to interleukin-11 in mice lacking the receptor for thrombopoietin (TPO) (mpl(-/-) mice).

RESULTS

The interleukin (IL)-11-responsive subset of progenitor cells was not detected in clonal cultures of bone marrow cells from mpl(-/-) mice. However, mpl(-/-) mice responded to IL-11 in vivo as evidenced by a rise in platelet count and an increase in spleen weight. Experiments were performed to address this paradox: administration of 5-fluorouracil with consequent "expansion" of early hematopoietic cells resulted in the appearance of IL-11-responsive cells in mpl(-/-) mice when assayed in in vitro cultures.

CONCLUSIONS

Thus, although mpl(-/-) mice have the capacity to produce IL-11-responsive progenitor cells, under steady state conditions their expansion is dependent on TPO. This is the first evidence that a specific subset of bone marrow progenitor/stem cells is altered in mpl(-/-) mice.

Cloning, expression analysis, and chromosomal localization of murine and human homologues of a Xenopus mix gene

We report the cloning and chromosomal localization of murine and human Mix genes, members of a subclass of paired-like homeobox genes of which the Xenopus laevis Mix.1 gene is the founding member. The murine Mix gene was mapped to the distal region of chromosome 1 and the human region to the syntenic region 1q41-42. Northern analysis and RT-PCR of murine adult and embryonic tissues demonstrated that Mix expression was restricted to the early embryo. Whole-mount in situ hybridization revealed patchy but symmetrical Mix expression in visceral endoderm of embryonic day (E)5.5 embryos. In slightly older embryos, the expression was skewed to one side of the embryo and by E6.5, at the onset of gastrulation, expression was seen in the epiblast, visceral endoderm, nascent mesoderm, and the primitive streak. This expression pattern was maintained in mid- and late-streak embryos. In early bud-stage embryos, expression was strongest in the proximal two thirds of the streak, extending to the base of the allantois. By the headfold-stage, expression was confined to the remnant of the primitive streak in the caudal region of the embryo and, after E8.0, in the caudal notochord and tail bud mesoderm. Mix transcripts were no longer detectable after embryonic day 9.5.

Effect of granulocyte-macrophage colony-stimulating factor on the generation of epidermal Langerhans cells

The role of granulocyte-macrophage colony-stimulating factor (GM-CSF) and Flt3 ligand in the in vivo development of Langerhans cells (LC) was assessed, considering both the steady-state levels of LC in the epidermis and the rate of LC recovery after depletion following lipopolysaccharide (LPS) treatment. The density of LC was determined by counting following IA-specific immunofluorescent staining of epidermal sections from mouse ears. LC levels were compared in beta common chain receptor null (beta c(-/-)) mice that fail to respond to GM-CSF interleukin-5 (IL-5), in GM-CSF transgenic mice with elevated GM-CSF levels, and in mice given daily injections of Flt3 ligand. In the steady state, LC levels were increased in GM-CSF transgenic mice and present at reduced levels in beta c(-/-) mice but unchanged in Flt3 ligand-injected mice. Application of LPS to the ears of control BL/6 mice led to an approximately 70% reduction in LC 4 days later, with recovery beginning by day 8 and a return to normal levels by 2 weeks. This recovery was significantly delayed in beta c(-/-) mice and unchanged in Flt3 ligand-injected mice. These results suggest that GM-CSF (but not Flt3 ligand) enhances recruitment/maturation of LC even though GM-CSF is not essential for their formation.

Cardiac septal and valvular dysmorphogenesis in mice heterozygous for mutations in the homeobox gene Nkx2-5

Heterozygous mutations in the cardiac homeobox gene, NKX2-5, underlie familial cases of atrial septal defect (ASD) with severe atrioventricular conduction block. In this study, mice heterozygous for Nkx2-5-null alleles were assessed for analogous defects. Although ASD occurred only rarely, atrial septal dysmorphogenesis was evident as increased frequencies of patent foramen ovale and septal aneurysm, and decreased length of the septum primum flap valve. These parameters were compounded by genetic background effects, and in the 129/Sv strain, septal dysmorphogenesis bordered on ASD in 17% of Nkx2-5 heterozygotes. In a proportion of neonatal heterozygotes, as well as in adults with ASD, we found that the size of the foramen ovale was significantly enlarged and altered in shape, potentially exposing the normally thin septum primum to excessive hemodynamic forces. Therefore, defective morphogenesis of the septum secundum may be one contributing factor in the generation of patent foramen ovale, septal aneurysm, and certain ASDs. Mild prolongation of P-R interval in females and an increased frequency of stenotic bicuspid aortic valves were also features of the Nkx2-5 heterozygous phenotype. Our data demonstrate that the complex effects of Nkx2-5 haploinsufficiency in mice are weaker but convergent with those in humans. As in the mouse, the phenotype of human NKX2-5 mutations may be modulated by interacting alleles.

Expression of interleukin-11 during the human menstrual cycle: coincidence with stromal cell decidualization and relationship to leukaemia inhibitory factor and prolactin

Interleukin-11 (IL-11) is crucial in the decidualization response of the uterine stroma to the implanting blastocyst in the mouse. This study examined the localization and expression of IL-11 in human endometrium throughout the menstrual cycle and of prolactin and leukaemia inhibitory factor (LIF) in secretory phase endometrium. The mRNA expression of IL-11 receptor alpha and the signalling component, gp130, in endometrial tissue were also determined. Immunoreactive IL-11 was highest in the secretory phase and present in decidualized stromal cells, glandular epithelial cells, endothelial and smooth muscle cells, and the mRNA expression was verified by in-situ hybridization. Decidual cells showed the most intense staining. IL-11 receptor alpha and gp130 mRNA were detected throughout the cycle with minimal variation. Expression of IL-11 mRNA and protein preceded that of prolactin. While immunoreactive prolactin was found in stromal, decidual and glandular epithelial cells, prolactin mRNA was confined to decidual cells. In contrast, endometrial LIF expression preceded IL-11 but was largely confined to the glandular epithelium. The sequence of appearance of LIF, IL-11 and prolactin suggests a synchronized role for each in the differentiation of the endometrium. The cyclical changes and cell type specific expression of IL-11 suggests a potential role in the decidualization of stromal cells.

Granulocyte-macrophage colony-stimulating factor is not responsible for residual thrombopoiesis in mpl null mice

OBJECTIVE

To examine the role of granulocyte-macrophage colony-stimulating factor (GM-CSF) in thrombopoiesis.

MATERIALS AND METHODS

Thrombopoietin-unresponsi ve mice (mpl null mice), which have a profound reduction in platelets and mature megakaryocytes, were interbred with mice that do not respond to GM-CSF or interleukin 5 (betac null mice), and hematopoiesis was examined. In initial experiments on a mixed genetic background, double mutant mice (betac/mpl null mice) showed an unexpected amelioration of the thrombocytopenia seen in mpl null mice. Platelet counts were elevated approximately twofold in betac/mpl null mice compared with mpl null mice (mpl null 73+/-31; betac/mpl null 164+/-70; n = 10 to 29 mice per genotype, p<0.00001). This was associated with lessening of the deficit of megakaryocytes, progenitor cells, and colony-forming units spleen seen in mpl null mice. This amelioration of the mpl null phenotype in betac/mpl null mice on a mixed genetic background was highly statistically significant. To determine whether this amelioration of phenotype was solely the consequence of loss of betac signaling, progeny of a second intercross on a C57BL/6 background (B6betac/mpl null mice) were examined. When the resulting B6betac/mpl null mice were analyzed and compared with B6mpl null littermates, the increase in platelet count, hematopoietic progenitor cell number, and colony-forming units spleen number was no longer observed.

CONCLUSION

There was no additional effect seen as a result of loss of betac signaling. GM-CSF did not play a significant role in thrombopoiesis, even in combination with the absence of thrombopoietin signaling. These results highlight problems that can be encountered when studying introduced mutations in mice. They exemplify the importance of eliminating the influence of modifying genes when attributing biologic differences to specific introduced genetic alterations.

Reassessment of interactions between hematopoietic receptors using common beta-chain and interleukin-3-specific receptor beta-chain-null cells: no evidence of functional interactions with receptors for erythropoietin, granulocyte colony-stimulating factor, or stem cell factor

Mice lacking both the gene encoding the shared receptor for granulocyte macrophage-colony-stimulating factor (GM-CSF), interleukin-3 (IL-3), and IL-5 common beta-chain (B(c)) and the gene for the IL-3 specific receptor (BIL3) were generated. This was achieved by targeting the B(c) locus in embryonic stem cells that were heterozygous for a null mutation of BIL3. Cells from mice generated with the doubly targeted embryonic stem cells were unresponsive to all 3 cytokines. Considerable previous data suggested a role for common beta-chain (beta(c)) in modulating signaling of cytokines including erythropoietin (EPO), G-CSF, and stem cell factor (SCF). However, bone marrow cells from mice lacking beta(c) and beta(IL3) showed normal responsiveness to these cytokines. Thus, there was no evidence for a biologically significant interaction between signaling via beta(c) or beta(IL3) and signaling by EPO, G-CSF, or SCF. Previously documented biochemical phenomena, including receptor transmodulation, receptor transphosphorylation, and even direct physical interaction, involving the beta(c)/beta IL-3 receptor systems do not reflect genuine interactions of physiological significance in primary hematopoietic cells. This study provided results that challenge conclusions previously established using a variety of biochemical assays. (Blood. 2000;96:1588-1590)

Homeodomain factor Nkx2-3 controls regional expression of leukocyte homing coreceptor MAdCAM-1 in specialized endothelial cells of the viscera

Regulated emigration of blood-borne leukocytes plays a defining role in lymphoid organ development, immune surveillance, and inflammatory responses. We report here that mice deficient in the homeobox gene Nkx2-3, expressed in developing visceral mesoderm, show a complex intestinal malabsorption phenotype and striking abnormalities of gut-associated lymphoid tissue and spleen suggestive of deranged leukocyte homing. Mutant Peyer's patches were reduced in number and size, intestinal villi contained few IgA(+) plasma cells, and mutant spleens were small and often atrophic, showing fused periarterial lymphoid sheaths, partially merged T and B cell zones, an absent marginal zone, and a dearth of macrophages in red pulp. Semiquantitative RT-PCR analysis and immunohistochemistry revealed down-regulation of mucosal addressin cell adhesion molecule-1 (MAdCAM-1) in endothelial cells in which Nkx2-3 is normally expressed. MAdCAM-1 is a member of the immunoglobulin superfamily, acting as an endothelial cell ligand for leukocyte homing receptors L-selectin and alpha4beta7 integrin. Our data suggest a role for a homeodomain factor in establishing the developmental and positional cues in endothelia that regulate leukocyte homing through local control of cellular adhesion and identify MAdCAM-1 as a candidate target gene of Nkx2-3.

Mice unresponsive to GM-CSF are unexpectedly resistant to cutaneous Leishmania major infection

Granulocyte-macrophage colony-stimulating factor (GM-CSF) has been shown to play a protective role in leishmanial infection. Mice with a null mutation in the gene for the beta common (beta c) chain of the receptors for GM-CSF, interleukin(IL)-3 and IL-5 (beta c-null mice) display normal steady state hemopoiesis and develop lung disease similar to the human condition, alveolar proteinosis, due to a lack of signaling by GM-CSF. We therefore expected to observe a heightened sensitivity to Leishmania major in the beta c-null mice. Surprisingly, the beta c-null mice were more resistant to cutaneous infection than wild-type (wt) mice. Upon intradermal injection of L. major promastigotes, fewer beta c-null mice developed cutaneous lesions than wt mice and these lesions were smaller and healed more rapidly than in wt mice. This resistance to disease was associated with a reduced percentage of in vitro infected beta c-null macrophages. Macrophages from beta c-null mice displayed a more activated phenotype and produced increased amounts of nitric oxide following infection with L. major, both in vivo and in vitro. Paradoxically, however, the parasite burden in the draining lymph nodes was similar in both beta c-null and wt mice, suggesting that at least a subpopulation of cells was susceptible to the parasite. The mechanism preventing normal lesion development remains to be elucidated.

Polyethylene glycol-modified GM-CSF expands CD11b(high)CD11c(high) but notCD11b(low)CD11c(high) murine dendritic cells in vivo: a comparative analysis with Flt3 ligand

Dendritic cells (DC) are potent APCs that can be characterized in the murine spleen as CD11b(high)CD11c(high) or CD11b(low)CD11c(high). Daily injection of mice of Flt3 ligand (FL) into mice transiently expands both subsets of DC in vivo, but the effect of administration of GM-CSF on the expansion of DC in vivo is not well defined. To gain further insight into the role of GM-CSF in DC development and function in vivo, we treated mice with polyethylene glycol-modified GM-CSF (pGM-CSF) which has an increased half-life in vivo. Administration of pGM-CSF to mice for 5 days led to a 5- to 10-fold expansion of CD11b(high)CD11c(high) but not CD11b(low)CD11c(high) DC. DC from pGM-CSF-treated mice captured and processed Ag more efficiently than DC from FL-treated mice. Although both FL- and pGM-CSF-generated CD11b(high)CD11c(high) DC were CD8alpha-, a greater proportion of these DC from pGM-CSF-treated mice were 33D1+ than from FL-treated mice. CD11b(low)CD11c(high) DC from FL-treated mice expressed high levels of intracellular MHC class II. DC from both pGM-CSF- and FL-treated mice expressed high levels of surface class II, low levels of the costimulatory molecules CD40, CD80, and CD86 and were equally efficient at stimulating allogeneic and Ag-specific T cell proliferation in vitro. The data demonstrate that treatment with pGM-CSF in vivo preferentially expands CD11b(high)CD11c(high) DC that share phenotypic and functional characteristics with FL-generated CD11b(high)CD11c(high) DC but can be distinguished from FL-generated DC on the basis of Ag capture and surface expression of 33D1.

Distinct changes in pulmonary surfactant homeostasis in common beta-chain- and GM-CSF-deficient mice

Pulmonary alveolar proteinosis (PAP) is caused by inactivation of either granulocyte-macrophage colony-stimulating factor (GM-CSF) or GM receptor common beta-chain (beta(c)) genes in mice [GM(-/-), beta(c)(-/-)], demonstrating a critical role of GM-CSF signaling in surfactant homeostasis. To distinguish possible phenotypic differences in GM(-/-) and beta(c)(-/-) mice, surfactant metabolism was compared in beta(c)(-/-), GM(-/-), and wild-type mice. Although lung histology in beta(c)(-/-) and GM(-/-) mice was indistinguishable, distinct differences were observed in surfactant phospholipid and surfactant protein concentrations and clearance from lungs of beta(c)(-/-) and GM(-/-) mice. At 1-2 days of age, lung saturated phosphatidylcholine (Sat PC) pool sizes were higher in wild-type, beta(c)(-/-), and GM(-/-) mice compared with wild-type adult mice. In wild-type mice, Sat PC pool sizes decreased to adult levels by 7 days of age; however, Sat PC increased with advancing age in beta(c)(-/-) and GM(-/-) mice. Postnatal changes in Sat PC pool sizes were different in GM(-/-) compared with beta(c)(-/-) mice. After 7 days of age, the increased lung Sat PC pool sizes remained constant in beta(c)(-/-) mice but continued to increase in GM(-/-) mice, so that by 56 days of age, lung Sat PC pools were increased three- and sixfold, respectively, compared with wild-type controls. After intratracheal injection, the percent recovery of [(3)H]dipalmitoylphosphatidylcholine and (125)I-recombinant surfactant protein (SP) C was higher in beta(c)(-/-) compared with wild-type mice, reflecting decreased clearance in the receptor-deficient mice. The defect in clearance was significantly more severe in GM(-/-) than in beta(c)(-/-) mice. The ratio of SP Sat PC to SP-A, -B, and -C was similar in bronchoalveolar lavage fluid (BALF) from adult mice of all genotypes, but the ratio of SP-D to Sat PC was markedly increased in beta(c)(-/-) and GM(-/-) mice (10- and 5-fold, respectively) compared with wild-type mice. GM-CSF concentrations were increased in BALF but not in serum of beta(c)(-/-) mice, consistent with a pulmonary response to the lack of GM-CSF signaling. The observed differences in surfactant metabolism suggest the presence of alternative clearance mechanisms regulating surfactant homeostasis in beta(c)(-/-) and GM(-/-) mice and may provide a molecular basis for the range in severity of PAP symptoms. surfactant metabolism; alveolar macrophage; granulocyte-macrophage colony-stimulating factor

Targeted insertion of a lacZ reporter gene into the mouse Cer1 locus reveals complex and dynamic expression during embryogenesis

The mouse Cer1 (mCer1, Cer-l, Cerr1) gene encodes one member of a family of cytokines structurally and functionally related to the Xenopus head-inducing factor, Cerberus (xCer). We generated a mouse line in which the Cer1 gene was inactivated by replacing the first coding exon with a lacZ reporter gene. Mice homozygous for this allele (Cer1(lacZ)) showed no apparent perturbation of embryogenesis or later development. However, the lacZ reporter revealed a number of hitherto uncharacterised sites of Cer1 expression in late fetal and adult tissues. Preliminary analysis suggests that Cer1 is not essential for their morphogenesis, differentiation, or homeostasis.

The residual megakaryocyte and platelet production in c-mpl-deficient mice is not dependent on the actions of interleukin-6, interleukin-11, or leukemia inhibitory factor

Mice lacking thrombopoietin (TPO) or its receptor c-Mpl are severely thrombocytopenic, consistent with a dominant physiological role for this cytokine in megakaryocytopoiesis. However, these mice remain healthy and show no signs of spontaneous hemorrhage, implying that TPO-independent mechanisms for platelet production exist and are sufficient for hemostasis. To investigate the roles of cytokines that act through the gp130 signaling chain in the residual platelet production of mpl (-/-) mice, mpl (-/-)IL-6(-/-), mpl(-/-)LIF(-/-), and mpl(-/-)IL-11Ralpha(-/-) double-mutant mice were generated. In each of these compound mutants, the number of circulating platelets was no lower than that observed in mice lacking only the c-mpl gene. Moreover, the deficits in the numbers of megakaryocytes and megakaryocyte progenitor cells in the bone marrow and spleen were no further exacerbated in mpl(-/-)IL-6(-/-), mpl(-/-)LIF(-/-), or mpl(-/-)IL-11Ralpha(-/-) double-mutant mice compared with those in Mpl-deficient animals. In single IL-6(-/-), LIF(-/-), and IL-11Ralpha(-/-) mutant mice, platelet production was normal. These data establish that, as single regulators, IL-6, IL-11, and LIF have no essential role in normal steady-state megakaryocytopoiesis, and are not required for the residual megakaryocyte and platelet production seen in the c-mpl(-/-) mouse. (Blood. 2000;95:528-534)

SCL expression in the mouse embryo detected with a targeted lacZ reporter gene demonstrates its localization to hematopoietic, vascular, and neural tissues

The helix-loop-helix transcription factor SCL (TAL1) is indispensable for blood cell formation in the mouse embryo. We have explored the localization and developmental potential of cells fated to express SCL during murine development using SCL-lacZ mutant mice in which the Escherichia coli lacZ reporter gene was 'knocked in' to the SCL locus. In addition to the hematopoietic defect associated with SCL deficiency, the yolk sac blood vessels in SCL(lacZ/lacZ) embryos formed an abnormal primary vascular plexus, which failed to undergo subsequent remodeling and formation of large branching vessels. Intraembryonic vasculogenesis in precirculation SCL(lacZ/lacZ) embryos appeared normal but, in embryos older than embryonic day (E) 8.5 to E9, absolute anemia leading to severe hypoxia precluded an accurate assessment of further vascular development. In heterozygous SCL(lacZ/w) embryos, lacZ was expressed in the central nervous system, vascular endothelia, and primitive and definitive hematopoietic cells in the blood, aortic wall, and fetal liver. Culture of fetal liver cells sorted for high and low levels of beta galactosidase activity from SCL(lacZ/w) heterozygous embryos indicated that there was a correlation between the level of SCL expression and the frequency of hematopoietic progenitor cells.