Developing a high fidelity, low cost simulation model for retrosigmoid craniotomy and microvascular decompression of the trigeminal nerve.

BACKGROUND: Trigeminal neuralgia is a very painful condition that may require a surgical approach as treatment, which is typically retrosigmoid craniotomy followed by microvascular decompression. Due to the limited margin for error when operating in the small triangular window of the cerebellopontine angle and the infrequency of this condition, the operating room can present a difficult learning environment for surgical trainees. Our aim is to create a synthetic, low-cost, high-fidelity, and largely reusable simulation model that will enable neurosurgical trainees to practice these procedural steps in a safe learning environment. MATERIALS AND METHODS: Design-based research was employed to develop the model through iterative micro-cycles, with expert evaluation from an educational and clinical team. The model was made from easy to source materials without advanced technology where sustainability, reproduction at scale and cost where significant considerations. RESULTS: Our model effectively simulates a retrosigmoid craniotomy and microvascular decompression of the trigeminal nerve. The model consists of two distinct parts that are made of synthetic materials. Part A is a single-use, moulded portion of the skull, while part B depicts the cerebellopontine angle and some of its internal anatomical and pathological structures crucial to carrying out all the steps to this procedure. Part A sits ergonomically flush on top of Part B, with both parts subsequently clamped to the table. CONCLUSIONS: As a proof of concept, we report the development and utilisation of a novel, low-cost, replicable retrosigmoid craniotomy and microvascular decompression of the trigeminal nerve simulation model.

The peptide neuromedin U (NMU) is elevated in NYHA II and III heart failure.

AIMS: Currently, there is no reliable biomarker to detect pre-heart failure in humans. An early risk signal is an elevated left atrial pressure (LAP) and preliminary results from animal studies strongly suggest the neuropeptide neuromedin U (NMU) is released in response to this increase in LAP. However, it is unknown whether NMU is elevated in patients with heart failure. Therefore, the aim of this study was to assess if NMU levels are elevated in human cases of heart failure. METHODS AND RESULTS: Twenty-four serum samples were obtained from patients in stage II and III heart failure from the Royal Papworth Hospital in Cambridge UK and tested using a selective NMU-ELISA; the data were compared with serum obtained commercially from self-declared healthy donors. NMU concentrations in serum from heart failure patients were significantly higher (P = 0.0007; unpaired Student's t-test) than control, 8.48 ± 0.67 ng/mL (mean ± SEM) versus 5.43 ± 0.46 ng/mL. There was no significant difference between NYHA stage II and III patients (P = 0.85, unpaired Student's t-test), which were 8.33 ± 0.89 ng/mL (n = 9) and 8.6 ± 0.95 ng/mL (n = 15), respectively. Only mean right atrial pressure was found to have a significant correlation with serum NMU (R = 0.81, P < 0.00001; regression analysis). CONCLUSIONS: NMU is elevated in serum from stage II and III heart failure patients, supporting data from our pre-heart failure animal model; however, further study is needed to determine whether NMU is a reliable biomarker for pre-heart failure.

When does too little pressure become too much? A case of spontaneous intracranial hypotension presenting with acute loss of consciousness.

Background: We present a unique case of spontaneous intracranial hypotension (SIH) presenting with acute collapse and loss of consciousness. Case Description: The affected patient suffered an abrupt decline in level of consciousness several weeks after initial diagnosis. The patient was urgently transferred to a specialist neurosurgical unit. Imaging showed bilateral subdural fluid collections with significant associated local mass effect. The treating team faced a clinical conundrum with a lack of clarity as to whether this sudden deterioration was secondary to the local pressure effect on brainstem traction from reduced intracranial pressure. A decision was made to proceed with urgent burr-hole decompression of the bilateral subdural fluid collections. Conclusion: After a protracted, complex postoperative course, the patient recovered to full functional independence. To the author's knowledge, this is the first case in literature describing successful surgical management of SIH, with bilateral burr-hole evacuation to relieve the paradoxical mass effect of bilateral subdural fluid collections.

Chronic Intermittent Hypoxia-Induced Diaphragm Muscle Weakness Is NADPH Oxidase-2 Dependent.

Chronic intermittent hypoxia (CIH)-induced redox alterations underlie diaphragm muscle dysfunction. We sought to establish if NADPH oxidase 2 (NOX2)-derived reactive oxygen species (ROS) underpin CIH-induced changes in diaphragm muscle, which manifest as impaired muscle performance. Adult male mice (C57BL/6J) were assigned to one of three groups: normoxic controls (sham); chronic intermittent hypoxia-exposed (CIH, 12 cycles/hour, 8 h/day for 14 days); and CIH + apocynin (NOX2 inhibitor, 2 mM) administered in the drinking water throughout exposure to CIH. In separate studies, we examined sham and CIH-exposed NOX2-null mice (B6.129S-CybbTM1Din/J). Apocynin co-treatment or NOX2 deletion proved efficacious in entirely preventing diaphragm muscle dysfunction following exposure to CIH. Exposure to CIH had no effect on NOX2 expression. However, NOX4 mRNA expression was increased following exposure to CIH in wild-type and NOX2 null mice. There was no evidence of overt CIH-induced oxidative stress. A NOX2-dependent increase in genes related to muscle regeneration, antioxidant capacity, and autophagy and atrophy was evident following exposure to CIH. We suggest that NOX-dependent CIH-induced diaphragm muscle weakness has the potential to affect ventilatory and non-ventilatory performance of the respiratory system. Therapeutic strategies employing NOX2 blockade may function as an adjunct therapy to improve diaphragm muscle performance and reduce disease burden in diseases characterised by exposure to CIH, such as obstructive sleep apnoea.

NADPH oxidase 2 is necessary for chronic intermittent hypoxia-induced sternohyoid muscle weakness in adult male mice.

NEW FINDINGS: What is the central question of this study? Exposure to chronic intermittent hypoxia (CIH) evokes redox changes, culminating in impaired upper airway muscle function: what is the specific source of CIH-induced reactive oxygen species? What is the main finding and its importance? Profound sternohyoid muscle dysfunction following exposure to CIH was entirely prevented by apocynin co-treatment or NADPH oxidase 2 (NOX2) deletion. The results have implications for human obstructive sleep apnoea syndrome and point to antioxidant intervention, potentially targeting NOX2 blockade, as a therapeutic strategy. ABSTRACT: Exposure to chronic intermittent hypoxia (CIH) evokes redox changes, culminating in impaired upper airway muscle function. We sought to determine if NADPH oxidase 2 (NOX2)-derived reactive oxygen species underpin CIH-induced maladaptive changes in upper airway (sternohyoid) muscle performance. Adult male mice (C57BL/6J) were assigned to one of three groups: normoxic controls (sham); CIH-exposed (CIH, 12 cycles/hour, 8 h/day for 14 days); and CIH + apocynin (NOX2 inhibitor, 2 mM) given in the drinking water throughout exposure to CIH. In addition, we studied sham and CIH-exposed NOX2-null mice (B6.129S-CybbTM1Din /J ). Profound sternohyoid muscle dysfunction following exposure to CIH was entirely prevented by apocynin co-treatment or NOX2 deletion. Exposure to CIH increased sternohyoid muscle NOX enzyme activity, with no alteration to the gene or protein expression of NOX subunits. There was no evidence of overt oxidative stress, muscle regeneration, inflammation or atrophy following exposure to CIH. We suggest that NOX-dependent CIH-induced upper airway muscle weakness increases vulnerability to upper airway obstruction. Our results have implications for human obstructive sleep apnoea syndrome and point to antioxidant intervention, potentially targeting NOX2 blockade, as a therapeutic strategy.

Intermixed arteriovenous malformation and hemangioblastoma: case report and literature review.

We report the third presentation of an intermixed arteriovenous malformation and hemangioblastoma. The rare occurrence of the diagnostic histologic features of both a neoplasm and vascular malformation in a single lesion is more common in gliomas, as angioglioma, and is termed an 'intermixed' lesion. We review the literature concerning the developmental biology of each lesion, and potential interplay in the formation of an intermixed vascular neoplasm and vascular malformation. The roles of cellular origin, genetic susceptibility, favourable microenvironment, altered local gene expression and key regulatory pathways are reviewed. Our review supports angiography and genetic profiling in intermixed lesions to inform management strategies. Consideration should be given to multimodality therapeutic interventions as required, including microsurgical resection, stereotactic radiosurgery and further research to exploit emerging molecular targets.

Predictors of Readmission Following Proctectomy for Rectal Cancer.

BACKGROUND: Unplanned readmission after surgery negatively impacts surgical recovery. Few studies have sought to define predictors of readmission in a rectal cancer cohort alone. Readmission following rectal cancer surgery may be reduced by the identification and modification of factors associated with readmission. OBJECTIVES: This study seeks to characterize the predictors of 30-day readmission following proctectomy for rectal cancer. DESIGN: This study is a retrospective analysis of prospectively gathered cohort data. Outcomes were compared between readmitted and nonreadmitted patients. Multivariate analysis of factors association with readmission was performed by using binary logistic regression. SETTINGS: This study was conducted at Beaumont Hospital, a nationally designated, publicly funded cancer center. PATIENTS: Two hundred forty-six consecutive patients who underwent proctectomy for rectal cancer between January 2012 and December 2015 were selected. MAIN OUTCOME MEASURES: The primary outcomes measured were readmission within 30 days of discharge and the variables associated with readmission, categorized into patient factors, perioperative factors, and postoperative factors. RESULTS: Thirty-one (12.6%) patients were readmitted within 30 days of discharge following index rectal resection. The occurrence of anastomotic leaks, high-output stoma, and surgical site infections was significantly associated with readmission within 30 days (anastomotic leak OR 3.60, p = 0.02; high-output stoma OR 11.04, p = 0.003; surgical site infections OR 13.39, p = 0.01). Surgical site infections and high-output stoma maintained significant association on multivariate analysis (surgical site infections OR 10.02, p = 0.001; high-output stoma OR 9.40, p = 0.02). No significant difference was noted in the median length of stay or frequency of prolonged admissions (greater than 24 days) between readmitted and nonreadmitted patients. LIMITATIONS: The institutional database omits a number of socioeconomic factors and comorbidities that may influence readmission, limiting our capacity to analyze the relative contribution of these factors to our findings. CONCLUSIONS: An early postoperative care bundle to detect postoperative complications could prevent some unnecessary inpatient admissions following proctectomy. Key constituents should include early identification and management of stoma-related complications and surgical site infection. See Video Abstract at http://links.lww.com/DCR/A912.

CNS metastasis secondary to malignant-mixed Müllerian tumor: case report and review of therapeutics.

This paper reviews CNS involvement secondary to malignant-mixed Müllerian tumor or uterine carcinosarcoma, a rare aggressive biphasic Müllerian tumor. We report a cerebellar metastasis with epithelial and mesenchymal components, demonstrating heterologous rhabdomyogenic and chondroblastic differentiation. The patient had undergone total abdominal hysterectomy and bilateral salpingo-oophorectomy for palliation of symptomatic chemotherapy-resistant node-positive disease. CNS involvement is rare, and prognostically poor, and suggestively poorer in predominantly sarcomatous metastases. Multimodal therapy is indicated; in solitary metastases, surgical resection or stereotactic radiosurgery is included, followed by whole brain radiotherapy. In unresectable brain metastases, stereotactic radiosurgery and whole brain radiotherapy warrant consideration in up to 2-3 metastases. In multiple metastases, palliative steroid therapy or cranial irradiation may be considered. Combination or platinum-based chemotherapy (i.e., ifosfamide-paclitaxel or carboplatin-paclitaxel) is indicated in all stages, with a role in both disease cure and control-directed management. Targeted therapeutics have thus far not demonstrated significant clinical efficacy.

Intrarenal Mas and AT1 receptors play a role in mediating the excretory actions of renal interstitial angiotensin-(1-7) infusion in anaesthetized rats.

NEW FINDINGS: What is the central question of this study? Dietary sodium manipulation alters the magnitude of angiotensin-(1-7) [Ang-(1-7)]-induced natriuresis. The present study sought to determine whether this was related to relative changes in the activity of intrarenal Mas and/or AT1 receptors. What is the main finding and its importance? Angiotensin-(1-7)-induced diuresis and natriuresis is mediated by intrarenal Mas receptors. However, intrarenal AT1 receptor blockade also had an inhibitory effect on Ang-(1-7)-induced natriuresis and diuresis. Thus, Ang-(1-7)-induced increases in sodium and water excretion are dependent upon functional Mas and AT1 receptors. We investigated whether angiotensin-(1-7) [Ang-(1-7)]-induced renal haemodynamic and excretory actions were solely dependent upon intrarenal Mas receptor activation or required functional angiotensin II type 1 (AT1 ) receptors. The renin-angiotensin system was enhanced in anaesthetized rats by prior manipulation of dietary sodium intake. Angiotensin-(1-7) and AT1 and Mas receptor antagonists were infused into the kidney at the corticomedullary border. Mas receptor expression was measured in the kidney. Mean arterial pressure, urine flow and fractional sodium excretion were 93 ± 4 mmHg, 46.1 ± 15.7 µl min-1  kg-1 and 1.4 ± 0.3%, respectively, in the normal-sodium group and 91 ± 2 mmHg, 19.1 ± 3.3 µl min-1  kg-1 and 0.7 ± 0.2%, respectively, in the low-sodium group. Angiotensin-(1-7) infusion had no effect on mean arterial pressure in rats receiving a normal-sodium diet but decreased it by 4 ± 5% in rats receiving a low-sodium diet (P < 0.05). Interstitial Ang-(1-7) infusion increased urine flow twofold and fractional sodium excretion threefold (P < 0.05) in rats receiving a normal-sodium diet and to a greater extent, approximately three- and fourfold, respectively, in rats receiving the low-sodium diet (both P < 0.05). Angiotensin-(1-7)-induced increases in urine flow and fractional sodium excretion were absent in both dietary groups during intrarenal AT1 or Mas receptor inhibition after either losartan or A-779, respectively. Thus, AT1 receptor activation, as well as Mas receptor activation, plays an essential role in mediating Ang-(1-7)-induced natriuresis and diuresis. Whether this is because Ang-(1-7) partly antagonizes AT1 receptors or whether Ang-(1-7)-induced natriuresis is mediated through AT1 -Mas receptor dimerization remains unclear.

Chronic intermittent hypoxia increases rat sternohyoid muscle NADPH oxidase expression with attendant modest oxidative stress.

Chronic intermittent hypoxia (CIH) causes upper airway muscle dysfunction. We hypothesized that the superoxide generating NADPH oxidase (NOX) is upregulated in CIH-exposed muscle causing oxidative stress. Adult male Wistar rats were exposed to intermittent hypoxia (5% O2 at the nadir for 90 s followed by 210 s of normoxia), for 8 h per day for 14 days. The effect of CIH exposure on the expression of NOX subunits, total myosin and 4-hydroxynonenal (4-HNE) protein adducts in sternohyoid muscle was determined by western blotting and densitometry. Sternohyoid protein free thiol and carbonyl group contents were determined by 1D electrophoresis using specific fluorophore probes. Aconitase and glutathione reductase activities were measured as indices of oxidative stress. HIF-1α content and key oxidative and glycolytic enzyme activities were determined. Contractile properties of sternohyoid muscle were determined ex vivo in the absence and presence of apocynin (putative NOX inhibitor). We observed an increase in NOX 2 and p47 phox expression in CIH-exposed sternohyoid muscle with decreased aconitase and glutathione reductase activities. There was no evidence, however, of increased lipid peroxidation or protein oxidation in CIH-exposed muscle. CIH exposure did not affect sternohyoid HIF-1α content or aldolase, lactate dehydrogenase, or glyceraldehyde-3-phosphate dehydrogenase activities. Citrate synthase activity was also unaffected by CIH exposure. Apocynin significantly increased sternohyoid force and power. We conclude that CIH exposure upregulates NOX expression in rat sternohyoid muscle with concomitant modest oxidative stress but it does not result in a HIF-1α-dependent increase in glycolytic enzyme activity. Constitutive NOX activity decreases sternohyoid force and power. Our results implicate NOX-dependent reactive oxygen species in CIH-induced upper airway muscle dysfunction which likely relates to redox modulation of key regulatory proteins in excitation-contraction coupling.

Gamma-melanocyte stimulating hormone regulates the expression and cellular localization of epithelial sodium channel in inner medullary collecting duct cells.

Gamma(2)-melanocyte-stimulating hormone (γ2MSH) is a peptide hormone released by the pituitary gland which is thought to act directly on the renal inner medulla to promote increased sodium excretion into urine (natriuresis). The aim of this study was to determine if a stable analog, [Nle(3), D-Phe(6)]-γ2MSH (NDP-γ2MSH), of the native peptide regulated the activity, expression and cellular localization of epithelial sodium channel (ENaC) in a murine inner medullary collecting duct (mIMCD-3) cell line. Our results indicate that expression of the γ2MSH receptor, melanocortin receptor 3 receptor (MC3R), is up-regulated by culturing the cells in media with an increased osmolality (∼400mOsm/kg). Furthermore, stimulation of cAMP signaling and sodium transport by 1nM NDP-γ2MSH occurs only in cells cultured in the high osmolality media. Finally, treatment of mIMCD-3 cells cultured in high osmolality medium for 1h with 1nM NDP-γ2MSH causes a reduction in expression of serum- and glucocorticoid-induced kinase (sgk1) and a reduction in expression and cell surface abundance of the alpha subunit of ENaC. Collectively, this data suggest that γ2MSH directly regulates both ENaC expression and cellular localization in the inner medulla to exert its natriuretic effect.

[Nle3,d-Phe6 ]-γ2 -melanocyte-stimulating hormone possesses the renal excretory but not the cardiovascular actions of the native γ2 -melanocyte-stimulating hormone in anaesthetized rats.

The present study compared the cardiovascular and renal actions of γ(2) -melanocyte-stimulating hormone (γ(2) MSH) with those of the synthetic analogue [Nle(3) ,d-Phe(6) ]-γ(2) MSH (NDP-γ(2) MSH) and explored the effects of high dietary salt intake on the renal actions of NDP-γ(2) MSH. Both peptides were infused systemically (3-1000 nmol/kg) and intrarenally (500 fmol/min) into innervated and renally denervated rats fed either a normal (0.4% NaCl) or high-salt (4% NaCl; HS) diet. Mean arterial pressure (MAP), glomerular filtration rate (GFR), urinary sodium excretion (U(N) (a) V), urinary output (UV) and fractional sodium excretion were determined, as was expression of the melanocortin MC(3) receptor in inner medullary collecting duct (IMCD) epithelial cells. Both renal and systemic infusion of γ(2) MSH increased MAP by 23 ± 2% and 54 ± 4%, respectively, but equivalent doses of NDP-γ(2) MSH had no significant pressor effects. Both peptides had similar natriuretic and diuretic effects in rats fed a normal salt diet. However, NDP-γ(2) MSH increased U(N) (a) V and UV by two- to threefold in rats fed the normal salt diet and by six- to sevenfold in rats fed the HS diet. Furthermore, NDP-γ(2) MSH induced a 3.5-fold increase in GFR only in rats fed the HS diet. These renal effects of NDP-γ(2) MSH were not abolished by prior renal denervation. Rats fed the HS diet also exhibited a 4.5-fold increase in MC(3) receptor expression in IMCD epithelial cells. Intrarenal infusion of NDP-γ(2) MSH induced the natriuretic but not the cardiovascular effects exhibited by γ(2) MSH. The renal activities may be attributed to a direct binding of NDP-γ(2) MSH to MC(3) receptors expressed in IMCD cells, leading to a potent natriuretic effect that is independent of renal innervation.

Impact of elevated dietary sodium intake on NAD(P)H oxidase and SOD in the cortex and medulla of the rat kidney.

Pathophysiological states, including cardiovascular and renal diseases, are characterized by oxidative stress but what is less clear is whether physiological challenges incur a degree of altered oxidative metabolism. To this end, this study examined whether exposure to a high dietary sodium intake could cause an oxidative stress at the kidney. Animals, placed on either 0.3% or 3% sodium diets for 2 wk, were given a lethal dose of anesthetic, and kidneys were removed to analyze both NAD(P)H oxidase (NOX) and superoxide dismutase (SOD) expression and activities in the cortex and medulla. Placing animals on the high-sodium diet raised sodium and water excretion and caused an approximately 14-fold increase in urinary excretion of 8-isoprostane, a marker of oxidative stress, which was attenuated by chronic treatment with apocynin to prevent NAD(P)H oxidase activity. The protein expression of the NAD(P)H oxidase subunits NOX2 and p47(phox) and overall NAD(P)H oxidase activity were approximately doubled in the cortex of the rats on the high-sodium diet compared with those on the normal sodium intake while both SOD activity and expression were unchanged. By contrast, neither NOX nor SOD protein expression or activity were altered in the medulla when the rats were placed on the high-sodium intake. These data suggest that an elevation in dietary sodium intake can lead to increased generation of reactive oxygen species and a state of oxidative stress in the cortex but not to such a degree that it extends to the medulla.

Aldosterone rapidly activates Na+/H+ exchange in M-1 cortical collecting duct cells via a PKC-MAPK pathway.

BACKGROUND: In this study, the mechanism of the rapid non-genomic effect of aldosterone on Na(+)/H(+) exchanger (NHE)-mediated intracellular pH (pH(i)) recovery from an acid load in murine M-1 cortical collecting duct cells was assessed. METHODS: Spectrofluorescence microscopy and Western blot analysis was carried out and NH(4)Cl was used to induce the acid load. RESULTS: Aldosterone (10 nM) induced a rapid (<5 min) concentration-dependent increase in pH(i) recovery in M-1 cells, an effect mimicked by its precursor deoxycorticosterone (1 nM). This response was unaffected by the mineralocorticoid receptor (MR) antagonist spironolactone (10 microM) but was significantly reduced by the NHE antagonists 5'-(N-ethyl- N-isopropyl)amiloride (EIPA) (20 microM) and cariporide (1 microM). The PKC inhibitor chelerythrine chloride (1 microM) significantly attenuated the aldosterone-induced increase in NHE1 activity. HBDDE (80 microM), a PKC(alpha) inhibitor, inhibited the rapid aldosterone effect whereas rottlerin (15 microM), a PKC(delta) antagonist, did not. The glucocorticoid receptor agonists hydrocortisone (1 microM) and dexamethasone (100 nM) decreased NHE activity, whereas the synthetic mineralocorticoid fludrocortisone (1 nM) had no significant effect. MAPK inhibition using PD98059 (25 microM) significantly attenuated the rapid aldosterone effect; Western blot analysis showed that aldosterone activation of ERK 1/2 was unaffected by pretreatment with spironolactone but was inhibited following chelerythrine chloride. CONCLUSION: Aldosterone causes a rapid non-genomic increase in NHE1 activity in M-1 cells via a PKC(alpha )/MAPK pathway independent of the classical MR.

17beta-Estradiol rapidly stimulates c-fos expression via the MAPK pathway in T84 cells.

In this study, we show that 17beta-Estradiol (E2) induced the proliferation of T84 colonic carcinoma cells. We, further, investigated the mechanisms underlying this proliferation and show that E2 induced c-fos protooncogene expression in T84 cells in a timescale consistent with a rapid non-genomic action of the hormone. Furthermore, E2 rapidly phosphorylated both CREB and ELK1, transcription factors that bind to the c-fos promoter and stimulate transcription. Pretreatment with PD98059 and H89, mitogen-activated protein kinase (MAPK) pathway and protein kinase A (PKA) inhibitors, respectively showed that phosphorylation of CREB and ELK1 and subsequent c-fos induction was mediated by the MAPK pathway only. Finally, the estrogen receptor (ER) antagonist, ICI 182,780, blocked the activation of MAPK pathway, subsequent CREB and ELK1 phosphorylation and c-fos induction in T84 cells suggesting an ER dependent mechanism. Consistent with this finding, ICI 182,780 caused a substantial reduction in the proliferative effects of E2 on T84 cells.

Rapid responses to steroid hormones: from frog skin to human colon. A homage to Hans Ussing.

Fifty years ago, Hans Ussing described the mechanism by which ions are actively transported across frog skin. Since then, an enormous amount of effort has been invested in determining the cellular and molecular specifics of the transport mechanisms and their regulatory pathways. Ion transport in high-resistance epithelia is regulated by a variety of hormonal and non-hormonal factors. In vertebrates, steroid hormones such as mineralocorticoids, glucocorticoids and estrogens are major regulators of ion and water transport and hence are central to the control of extracellular fluid volume and blood pressure. Steroid hormones act through nuclear receptors to control the transcriptional activity of specific target genes, such as ion channels, ion transporters and ion pumps. These effects are observed after a latency of several hours and can last for days leading to cellular differentiation that allows a higher transport activity. This pathway is the so-called genomic phase. However, in the past 10 years, it has become apparent that steroid hormones can regulate electrolyte and water transport in tight epithelia independently of the transcription of these ion channels and transporters by regulating ion transporter activity in a non-genomic fashion via modulation of various signal transduction pathways. The molecular mechanisms underlying the steroid hormone-induced activation of signal transduction pathways such as protein kinase C (PKC), protein kinase A (PKA), intracellular calcium, intracellular pH and mitogen-activated protein kinases (MAPKs) and how non-genomic activation of these pathways influences epithelial ion transport will be discussed in this review.