'Nasal flossing': A case report of nasopharyngeal stenosis due to severe erosive lichen planus and a novel therapeutic intervention.

INTRODUCTION: We describe a case of severe erosive oral lichen planus that led to nasopharyngeal stenosis. This is a rare clinical presentation that was ultimately, successfully treated by surgery combined with post-operative 'nasal flossing': a novel therapeutic intervention. PRESENTATION OF CASE: A 76-year-old male suffering from a rare case of severe oral lichen planus that was resistant to conservative measures is described. Initial surgery was complicated by recurrence of nasopharyngeal stenosis. Definitive surgery required revision of nasopharyngeal stenosis release combined with a course of post- operative 'nasal flossing'. The technique for 'nasal flossing' is described and demonstrated in photographs. The patient remained asymptomatic at 3 years using this combined approach, with restoration of olfaction, taste perception and voice quality, significantly enhancing quality of life. DISCUSSION: Erosive oral lichen planus is a rare but important presentation in oral medicine. We found 'nasal flossing' to be a successful treatment to maintain nasopharyngeal patency following surgical repair of this uncommon condition. We are not aware that this combined approach has previously been described in the published literature. CONCLUSIONS: Severe erosive oral lichen planus can lead to nasopharyngeal stenosis. Nasopharyngeal stenosis in these patients may be refractive to conventional surgical approaches. 'Nasal flossing' is demonstrated to be both practical and acceptable as a surgical adjunct in these difficult to treat cases of recurrent nasopharyngeal stenosis. This report has relevance for all those practicing oral and maxillofacial surgery, ear nose and throat surgery and oral medicine.

SINHCAF/FAM60A and SIN3A specifically repress HIF-2α expression.

The SIN3A-HDAC (histone deacetylase) complex is a master transcriptional repressor, required for development but often deregulated in disease. Here, we report that the recently identified new component of this complex, SINHCAF (SIN3A and HDAC-associated factor)/FAM60A (family of homology 60A), links the SIN3A-HDAC co-repressor complex function to the hypoxia response. We show that SINHCAF specifically represses HIF-2α mRNA and protein expression, via its interaction with the transcription factor SP1 (specificity protein 1) and recruitment of HDAC1 to the HIF-2α promoter. SINHCAF control over HIF-2α results in functional cellular changes in in vitro angiogenesis and viability. Our analysis reveals an unexpected link between SINHCAF and the regulation of the hypoxia response.

Validation of a semi-automated technique to accurately measure abdominal fat distribution using CT and MRI for clinical risk stratification.

OBJECTIVE: A valid method for accurate quantification of abdominal fat distribution (AFD) using both CT and MRI is described. This method will be primarily useful in the prospective risk stratification of patients undergoing reconstructive breast surgery. Secondary applications in many other clinical specialities are foreseen. METHODS: 15 sequential patients who had undergone breast reconstruction following both CT and MRI (30 scans) were retrospectively identified at our single centre. The AFD was quantified at the level of the L3 vertebra. Image analysis was performed by at least two independent operators using free software. Intra- and interobserver differences were assessed using Bland-Altman plots. Data were validated between imaging modalities by Pearson's correlation. Linear regression analyses were used to mathematically normalize results between imaging modalities. RESULTS: The method was statistically independent of rater bias (intra: Pearson's R-0.954-1.00; inter: 0.799-0.999). Strong relationships between imaging modalities were demonstrated and are independent of time between imaging (Pearson's R 0.625-0.903). Interchangeable mathematical models to normalize between imaging modality are shown. CONCLUSION: The method described is highly reproducible and independent of rater bias. A strong interchangeable relationship exists between calculations of AFD on retrospective CT and MRI. Advances in knowledge: This is the first technique to be applicable to scans that are not performed sequentially or in a research setting. Analysis is semi-automated and results can be compared directly, regardless of imaging modality or patient position. This method has clinical utility in prospective risk stratification and will be applicable to many clinical specialities.

Dyslexic doctors, an observation on current United Kingdom practice.

This article was migrated. The article was marked as recommended. Dyslexic doctors, an observation on current United Kingdom practice. ISSUE: Dyslexia is a common learning difficulty with an estimated prevalence of ten percent within the general population and two percent among junior doctors training in the United Kingdom. Despite dyslexia being common, there are still many challenges sufferers face in modern medical practice. EVIDENCE: Multiple case studies have found there to be barriers that dyslexic doctors face throughout their training. Common activities that required reading or writing in time pressured situations in front of an audience can impose an additional pressure for dyslexic doctors. In addition to the difficulties with day to day work, criticism and mockery from other staff members can make suffers of dyslexia feel undermined. From personal experiences, the authors of this article have found barriers are particularly present with regards to sitting post- graduate examinations and getting support in a modern time pressure health service. IMPLICATIONS: The discrepancy in the prevalence of learning difficulties between the general population and doctors in training might be due to barriers in training and difficulties when starting work. Addressing challenges will help support current dyslexic doctors and also help support future generations. Rapidly developing technology in health care makes it easier to accommodate doctors with additional needs but the impact of this are yet to be studied. If the barriers are addressed it is likely to support not only doctors with dyslexia diagnosis but all health care professionals.

Enhanced snoMEN Vectors Facilitate Establishment of GFP-HIF-1α Protein Replacement Human Cell Lines.

The snoMEN (snoRNA Modulator of gene ExpressioN) vector technology was developed from a human box C/D snoRNA, HBII-180C, which contains an internal sequence that can be manipulated to make it complementary to RNA targets, allowing knock-down of targeted genes. Here we have screened additional human nucleolar snoRNAs and assessed their application for gene specific knock-downs to improve the efficiency of snoMEN vectors. We identify and characterise a new snoMEN vector, termed 47snoMEN, that is derived from box C/D snoRNA U47, demonstrating its use for knock-down of both endogenous cellular proteins and G/YFP-fusion proteins. Using multiplex 47snoMEM vectors that co-express multiple 47snoMEN in a single transcript, each of which can target different sites in the same mRNA, we document >3-fold increase in knock-down efficiency when compared with the original HBII-180C based snoMEN. The multiplex 47snoMEM vector allowed the construction of human protein replacement cell lines with improved efficiency, including the establishment of novel GFP-HIF-1α replacement cells. Quantitative mass spectrometry analysis confirmed the enhanced efficiency and specificity of protein replacement using the 47snoMEN-PR vectors. The 47snoMEN vectors expand the potential applications for snoMEN technology in gene expression studies, target validation and gene therapy.

Cezanne regulates E2F1-dependent HIF2α expression.

Mechanisms regulating protein degradation ensure the correct and timely expression of transcription factors such as hypoxia inducible factor (HIF). Under normal O2 tension, HIFα subunits are targeted for proteasomal degradation, mainly through vHL-dependent ubiquitylation. Deubiquitylases are responsible for reversing this process. Although the mechanism and regulation of HIFα by ubiquitin-dependent proteasomal degradation has been the object of many studies, little is known about the role of deubiquitylases. Here, we show that expression of HIF2α (encoded by EPAS1) is regulated by the deubiquitylase Cezanne (also known as OTUD7B) in an E2F1-dependent manner. Knockdown of Cezanne downregulates HIF2α mRNA, protein and activity independently of hypoxia and proteasomal degradation. Mechanistically, expression of the HIF2α gene is controlled directly by E2F1, and Cezanne regulates the stability of E2F1. Exogenous E2F1 can rescue HIF2α transcript and protein expression when Cezanne is depleted. Taken together, these data reveal a novel mechanism for the regulation of the expression of HIF2α, demonstrating that the HIF2α promoter is regulated by E2F1 directly and that Cezanne regulates HIF2α expression through control of E2F1 levels. Our results thus suggest that HIF2α is controlled transcriptionally in a cell-cycle-dependent manner and in response to oncogenic signalling.

The role of hypoxia in inflammatory disease (review).

Mammals have developed evolutionarily conserved programs of transcriptional response to hypoxia and inflammation. These stimuli commonly occur together in vivo and there is significant crosstalk between the transcription factors that are classically understood to respond to either hypoxia or inflammation. This crosstalk can be used to modulate the overall response to environmental stress. Several common disease processes are characterised by aberrant transcriptional programs in response to environmental stress. In this review, we discuss the current understanding of the role of the hypoxia-responsive (hypoxia-inducible factor) and inflammatory (nuclear factor-κB) transcription factor families and their crosstalk in rheumatoid arthritis, inflammatory bowel disease and colorectal cancer, with relevance for future therapies for the management of these conditions.

HIF-1α restricts NF-κB-dependent gene expression to control innate immunity signals.

Hypoxia and inflammation are intimately linked. It is known that nuclear factor κB (NF-κB) regulates the hypoxia-inducible factor (HIF) system, but little is known about how HIF regulates NF-κB. Here, we show that HIF-1α represses NF-κB-dependent gene expression. HIF-1α depletion results in increased NF-κB transcriptional activity both in mammalian cells and in the model organism Drosophila melanogaster. HIF-1α depletion enhances the NF-κB response, and this required not only the TAK-IKK complex, but also CDK6. Loss of HIF-1α results in an increased angiogenic response in mammalian cancer cells and increased mortality in Drosophila following infection. These results indicate that HIF-1α is required to restrain the NF-κB response, and thus prevents excessive and damaging pro-inflammatory responses.

Hypoxia activates IKK-NF-κB and the immune response in Drosophila melanogaster.

Hypoxia, or low oxygen availability, is an important physiological and pathological stimulus for multicellular organisms. Molecularly, hypoxia activates a transcriptional programme directed at restoration of oxygen homoeostasis and cellular survival. In mammalian cells, hypoxia not only activates the HIF (hypoxia-inducible factor) family, but also additional transcription factors such as NF-κB (nuclear factor κB). Here we show that hypoxia activates the IKK-NF-κB [IκB (inhibitor of nuclear factor κB)-NF-κB] pathway and the immune response in Drosophila melanogaster. We show that NF-κB activation is required for organism survival in hypoxia. Finally, we identify a role for the tumour suppressor Cyld, as a negative regulator of NF-κB in response to hypoxia in Drosophila. The results indicate that hypoxia activation of the IKK-NF-κB pathway and the immune response is an important and evolutionary conserved response.

Analysis of global RNA synthesis at the single cell level following hypoxia.

Hypoxia or lowering of the oxygen availability is involved in many physiological and pathological processes. At the molecular level, cells initiate a particular transcriptional program in order to mount an appropriate and coordinated cellular response. The cell possesses several oxygen sensor enzymes that require molecular oxygen as cofactor for their activity. These range from prolyl-hydroxylases to histone demethylases. The majority of studies analyzing cellular responses to hypoxia are based on cellular populations and average studies, and as such single cell analysis of hypoxic cells are seldom performed. Here we describe a method of analysis of global RNA synthesis at the single cell level in hypoxia by using Click-iT RNA imaging kits in an oxygen controlled workstation, followed by microscopy analysis and quantification.  Using cancer cells exposed to hypoxia for different lengths of time, RNA is labeled and measured in each cell. This analysis allows the visualization of temporal and cell-to-cell changes in global RNA synthesis following hypoxic stress.

The double loop mattress suture.

An interrupted stitch type with favorable tissue characteristics will reduce local wound complications. We describe a novel high-strength, low-tension repair for the interrupted closure of skin, cartilage, and muscle, the double loop mattress stitch, and compare it experimentally with other interrupted closure methods. The performance of the double loop mattress technique in porcine cartilage and skeletal muscle is compared with the simple, mattress, and loop mattress interrupted sutures in both a novel porcine loading chamber and mechanical model. Wound apposition is assessed by electron microscopy. The performance of the double loop mattress in vivo was confirmed using a series of 805 pediatric laparotomies/laparoscopies. The double loop mattress suture is 3.5 times stronger than the loop mattress in muscle and 1.6 times stronger in cartilage (p ≤ 0.001). Additionally, the double loop mattress reduces tissue tension by 66% compared with just 53% for the loop mattress (p ≤ 0.001). Wound gapping is equal, and wound eversion appears significantly improved (p ≤ 0.001) compared with the loop mattress in vitro. In vivo, the double loop mattress performs as well as the loop mattress and significantly better than the mattress stitch in assessments of wound eversion and dehiscence. There were no episodes of stitch extrusion in our series of patients. The mechanical advantage of its intrinsic pulley arrangement gives the double loop mattress its favorable properties. Wound dehiscence is reduced because this stitch type is stronger and exerts less tension on the tissue than the mattress stitch. We advocate the use of this novel stitch wherever a high-strength, low-tension repair is required. These properties will enhance wound repair, and its application will be useful to surgeons of all disciplines.

Grow2: the HIF system, energy homeostasis and the cell cycle.

Cell cycle progression is an energy demanding process and requires fine-tuned metabolic regulation. Cells must overcome an energy restriction checkpoint before becoming committed to progress through the cell cycle. Aerobic organisms need oxygen for the metabolic conversion of nutrients into energy. As such, environmental oxygen is a critical signalling molecule regulating cell fate. The Hypoxia Inducible Factors (HIFs) are a family of transcription factors that respond to changes in environmental oxygen and cell energy and coordinate a transcriptional program which forms an important part of the cellular response to a hostile environment. A significant proportion of HIF-dependent transcriptional target genes, code for proteins that are involved in energy homeostasis. In this review we discuss the role of the HIF system in the regulation of energy homeostasis in response to changes in environmental oxygen and the impact on cell cycle control, and address the implications of the deregulation of this effect in cancer.

PITX1, a specificity determinant in the HIF-1α-mediated transcriptional response to hypoxia.

Hypoxia is an important developmental cue for multicellular organisms but it is also a contributing factor for several human pathologies, such as stroke, cardiovascular diseases and cancer. In cells, hypoxia activates a major transcriptional program coordinated by the Hypoxia Inducible Factor (HIF) family. HIF can activate more than one hundred targets but not all of them are activated at the same time, and there is considerable cell type variability. In this report we identified the paired-like homeodomain pituitary transcription factor (PITX1), as a transcription factor that helps promote specificity in HIF-1α dependent target gene activation. Mechanistically, PITX1 associates with HIF-1ß and it is important for the induction of certain HIF-1 dependent genes but not all. In particular, PITX1 controls the HIF-1α-dependent expression of the histone demethylases; JMJD2B, JMJD2A, JMJD2C and JMJD1B. Functionally, PITX1 is required for the survival and proliferation responses in hypoxia, as PITX1 depleted cells have higher levels of apoptotic markers and reduced proliferation. Overall, our study identified PITX1 as a key specificity factor in HIF-1α dependent responses, suggesting PITX1 as a protein to target in hypoxic cancers.

Herpes zoster induced acute urinary retention in the immunocompetent female.

We present a rare case of acute urinary retention complicated by constipation secondary to a unilateral herpes zoster reactivation in the S2-4 dermatomes of an immunocompetent female. Diagnosis was confirmed by clinical examination, negative cystoscopy and positive viral polymerase chain reaction (PCR) for herpes zoster virus. The patient was commenced on a course of oral acyclovir, the bowel symptoms resolved, and the patient was discharged with a urinary catheter in situ for an outpatient trial without catheter for 2 weeks to be followed by a course of intermittent self catheterisation pending resolution of symptoms.