A synthetic HIV-1 Rev inhibitor interfering with the CRM1-mediated nuclear export

The HIV-1 Rev protein is an essential regulator of the HIV-1 mRNA expression that promotes the export of unspliced and partially spliced mRNA. The export receptor for the leucine-rich nuclear export signal (NES) of Rev has recently been recognized as CRM1. We identified a low molecular weight compound PKF050-638 as an inhibitor of HIV-1 Rev. This drug inhibits in a dose-dependent fashion Rev-dependent mRNA expression in a cellular assay for Rev function. We show that PKF050-638 is an inhibitor of the CRM1-mediated Rev nuclear export. By using a quantitative in vitro CRM1-NES cargo-binding assay, we could demonstrate that PKF050-638 disrupts CRM1-NES interaction. This mode of action is confirmed in cell culture because the drug reversibly interferes with the colocalization of CRM1 and Rev in the nucleolus of the cell. In addition, we prove that the inhibition is through direct interaction of the compound with Cys-539 of CRM1. These effects are similar to those of the known CRM1 inhibitor leptomycin B and suggest that the inhibitory effect of the compound is caused by binding to CRM1 at a similar site. The compound displayed strict structural requirements for its activity, as its enantiomer was inactive in all assays tested. These results show that we identified a drug that interferes with the CRM1-mediated nuclear export of Rev through inhibition of the CRM1-NES complex formation. The reversibility of its binding to CRM1 and its availability through chemical synthesis could make it useful for studying CRM1-mediated export pathways.     

Staphylococcus aureus meningitis: experience with cefuroxime treatment during a 16 year period in a Danish region

Staphylococcus aureus is a rare cause of bacterial meningitis and there is no consensus on antibiotic treatment. Nafcillin is a common choice in countries where it is approved and marketed. High-dose cefuroxime has been the systemic treatment used in the study region, and a retrospective record review was conducted to determine its clinical efficacy. Cases of bacterial meningitis during 1984-1999 in the County of North Jutland, Denmark (approx. 490000 inhabitants), were identified in a regional bacteriology register. Inclusion of a case required either growth of S. aureus from > or = 2 specimens of cerebrospinal fluid (CSF), 1 positive CSF specimen with a CSF leucocyte count > 10(8)/l or 1 positive CSF specimen with a concurrent positive blood culture. A diagnosis of brain abscess required growth of S. aureus from aspirated pus. Staphylococcus aureus meningitis was confirmed in 45 patients, and 5 additional patients had a brain abscess. 44 cases were nosocomial (mortality 16%) and 6 were community acquired (mortality 83%). None of the isolates was methicillin resistant and 6 were penicillin susceptible. Intraventricular antibiotic treatment was given to 28 patients, systemic therapy included cefuroxime in 32 patients (64%) as either a primary or secondary choice, 6 (12%) were treated with penicillin G, 10 (20%) with penicillinase-resistant penicillin and 2 (4%) with cephalothin. Among 31 nosocomial cases treated systemically with cefuroxime the mortality was 10% (95% exact confidence limits 2-26%). In conclusion, cefuroxime seems to be a valid choice for S. aureus meningitis in the nosocomial setting.     

Aortocaval fistula after stent-graft repair.

PURPOSE: To report an aortocaval fistula after stent-graft repair and the feasibility of interventional treatment. CASE REPORT: A 78-year-old man with a 61-mm infrarenal aortic aneurysm (AA) was treated successfully with a Zenith bifurcated stent-graft. Three years later, the patient presented with deteriorating renal function and acute bronchial obstruction. Computed tomography showed an aortic diameter increased to 90 mm, dilatation of the inferior vena cava, and a distal type I endoleak. The patient's condition quickly deteriorated, and emergent imaging found a fistula with brisk flow between the aneurysm sac and the left iliac vein within a distal type I endoleak. During emergency endovascular repair, iliac extensions were implanted in the right common iliac artery and left external iliac artery. The left hypogastric artery was coil embolized to exclude flow into the aneurysm sac. After positioning the extensions, cardiac function improved, and the fistula was no longer palpable. The cardiac indices and renal function normalized, and he was discharged 20 days after admission. CONCLUSION: Aortocaval fistulas are a rare complication of AA stent-graft repair and may be successfully treated by interventional means.     

Pancreatic exocrine insufficiency in LXRbeta-/- mice is associated with a reduction in aquaporin-1 expression

Liver X receptors (LXRs) α and β are nuclear oxysterol receptors with a key role in cholesterol, triglyceride, and glucose metabolism. In LXRβ^−/− mice on a normal diet, there is a reduction in size of perigonadal fat pad and, on high-fat diet there is resistance to obesity. In the present study, we investigated the reason for the resistance of LXRβ^−/− mice to weight gain. In LXRβ^−/− mice we found pancreatic exocrine insufficiency with reduced serum levels of amylase and lipase, reduced proteolytic activity in feces, chronic inflammatory infiltration, and, in the ductal epithelium, an increased apoptosis without compensatory proliferation. Electron microscopy revealed ductal dilatation with intraductal laminar structures characteristic of cystic fibrosis. To investigate the relationship between LXRβ and pancreatic secretion, we studied the expression of LXRβ and the water channel, aquaporin-1 (AQP1), in the ductal epithelium of the pancreas. In WT mice, ductal epithelial cells expressed LXRβ in the nuclei and AQP1 on the plasma membrane. In LXRβ^−/− mice neither LXRβ nor AQP1 was detectable. Moreover, in WT mice the LXR agonist (T2320) increased AQP1 gene expression. These data demonstrate that in LXRβ^−/− mice dietary resistance to weight gain is caused by pancreatic insufficiency and that LXRβ regulates pancreatic exocrine secretion through the control of AQP1 expression. Pancreatic exocrine insufficiency is the main cause of malabsorption syndrome responsible for weight loss in adults and growth failure in children. Several genes are known to be involved in the pathogenesis and susceptibility to pancreatic insufficiency. LXRβ should be included in that list.     

The Contribution of the Left Phrenic Nerve to Innervation of the Esophagogastric Junction

The contribution of the left phrenic nerve to innervation of the esophagogastric junction. The esophagogastric junction is part of the barrier preventing gastroesophageal reflux. We have investigated the contribution of the phrenic nerves to innervation of the esophagogastric junction in humans and piglets by dissecting 30 embalmed human specimens and 14 piglets. Samples were microdissected and nerves were stained and examined by light and electron microscopy. In 76.6% of the human specimens, the left phrenic nerve participated in the innervation of the esophagogastric junction by forming a neural network together with the celiac plexus (46.6%) or by sending off a distinct phrenic branch, which joined the anterior vagal trunk (20%). Distinct left phrenic branches were always accompanied by small branches of the left inferior phrenic artery. In 10% there were indirect connections with a distinct phrenic nerve branch joining the celiac ganglion, from which celiac plexus branches to the esophagogastric junction emerged. Morphological examination of phrenic branches revealed strong similarities to autonomic celiac plexus branches. There was no contribution of the left phrenic nerve or accompanying arteries from the caudal phrenic artery in any of the piglets. The right phrenic nerve made no contribution in any of the human or piglet samples. We conclude that the left phrenic nerve in humans contributes to the innervation of the esophagogastric junction by providing ancillary autonomic nerve fibers. Experimental studies of the innervation in pigs should consider that neither of the phrenic nerves was found to contribute. Clin. Anat. 33:265–274, 2020. © 2019 Wiley Periodicals, Inc.