Intestinal barrier function in response to abundant or depleted mucosal glutathione in Salmonella-infected rats

Background  

Glutathione, the main antioxidant of intestinal epithelial cells, is suggested to play an important role in gut barrier function and prevention of inflammation-related oxidative damage as induced by acute bacterial infection. Most studies on intestinal glutathione focus on oxidative stress reduction without considering functional disease outcome. Our aim was to determine whether depletion or maintenance of intestinal glutathione changes susceptibility of rats to Salmonella infection and associated inflammation.     

Familial juvenile hyperuricaemic nephropathy is not such a rare genetic metabolic purine disease in Britain

Renal disease is rare today in classic adult gout, and gout is rare in renal disease--especially in the young. Here we summarise studies in 158 patients from 31 kindreds diagnosed with familial juvenile hyperuricaemic nephropathy FJHN from a total of 230 kindred members studied in Great Britain. Some patients have been followed for up to 30 years, and allopurinol has ameliorated the progression of the renal disease in all 113 surviving members provided: They have been diagnosed and treated sufficiently early. Compliance with allopurinol treatment and diet has been as important as early recognition. Hypertension has been rigorously controlled. The use of oral contraceptives has been avoided, as has pregnancy in any female with a Glomelar Filtration Rate GFR <70 ml/min. The question arising is: Why is FJHN the most prevalent genetic purine disorder diagnosed in Britain? Is it a lack of awareness which needs to be improved Europe-wide?     

Inhibition of the pneumococcal virulence factor StrH and molecular insights into N-glycan recognition and hydrolysis

The complete degradation of N-linked glycans by the pathogenic bacterium Streptococcus pneumoniae is facilitated by the large multimodular cell wall-attached exo-β-D-N-acetylglucosaminidase StrH. Structural dissection of this virulence factor using X-ray crystallography showed it to have two structurally related glycoside hydrolase family 20 catalytic domains, which displayed the expected specificity for complex N-glycans terminating in N-acetylglucosamine but exhibited unexpected differences in their preferences for the substructures present in these glycans. The structures of the two catalytic domains in complex with unhydrolyzed substrates, including an N-glycan possessing a bisecting N-acetylglucosamine residue, revealed the specific architectural features in the active sites that confer their differential specificities. Inhibitors of StrH are demonstrated to be effective tools in modulating the interaction of StrH with components of the host, such as the innate immune system. Overall, new structural and functional insight into a carbohydrate-mediated component of the pneumococcus-host interaction is provided.     

Morphine and Clonidine Combination Therapy Improves Therapeutic Window in Mice: Synergy in Antinociceptive but Not in Sedative or Cardiovascular Effects

Opioids are used to manage all types of pain including acute, cancer, chronic neuropathic and inflammatory pain. Unfortunately, opioid-related adverse effects such as respiratory depression, tolerance, physical dependence and addiction have led to an underutilization of these compounds for adequate pain relief. One strategy to improve the therapeutic utility of opioids is to co-administer them with other analgesic agents such as agonists acting at α₂-adrenergic receptors (α₂ARs). Analgesics acting at α₂ARs and opioid receptors (ORs) frequently synergize when co-administered in vivo. Multimodal analgesic techniques offer advantages over single drug treatments as synergistic combination therapies produce analgesia at lower doses, thus reducing undesired side effects. This inference presumes, however, that the synergistic interaction is limited to the analgesic effects. In order to test this hypothesis, we examined the effects of α₂AR/OR combination therapy in acute antinociception and in the often-undesired side effects of sedation and cardiovascular depression in awake unrestrained mice. Morphine, clonidine or their combination was administered by spinal or systemic injection in awake mice. Antinociception was determined using the warm water tail flick assay (52.5°C). Sedation/motor impairment was evaluated using the accelerating rotarod assay and cardiovascular function was monitored by pulse oximetry. Data were converted to percent maximum possible effect and isobolographic analysis was performed to determine if an interaction was subadditive, additive or synergistic. Synergistic interactions between morphine and clonidine were observed in the antinociceptive but not in the sedative/motor or cardiovascular effects. As a result, the therapeutic window was improved ∼200-fold and antinociception was achieved at non-sedating doses with little to no cardiovascular depression. In addition, combination therapy resulted in greater maximum analgesic efficacy over either drug alone. These data support the utility of combination adrenergic/opioid therapy in pain management for antinociceptive efficacy with reduced side-effect liability.     

Purine nucleoside phosphorylase deficiency: a mutation update

Purine nucleoside phosphorylase (PNPase) deficiency is an autosomal recessive disorder affecting purine degradation and salvage pathways. Clinically, patients typically present with severe immunodeficiency, neurological dysfunction, and autoimmunity. Biochemically, PNPase deficiency may be suspected in the presence of hypouricemia. We report biochemical and genetic data on a cohort of seven patients from six families identified as PNPase deficient. In all patients, inosine, deoxyinosine, guanosine, and deoxyguanosine were elevated in urine, and mutation analysis revealed seven different mutations of which three were novel. The mutation c.770A>G resulted in the substitution p.His257Arg. A second novel mutation c.257A>G (p.His86Arg) was identified in two siblings and a third novel mutation, c.199C>T (p.Arg67X), was found in a 2-year-old female with delayed motor milestones and recurrent respiratory infections. A review of the literature identified 67 cases of PNPase deficiency from 49 families, including the cases from our own laboratory. PNPase deficiency was confirmed in 30 patients by genotyping and 24 disease causing mutations, including the three novel mutations described in this paper, have been reported to date. In five of the seven patients, plasma uric acid was found to be within the pediatric normal range, suggesting that PNPase deficiency should not be ruled out in the absence of hypouricemia.     

Effect of pretreatment clinical factors on overall survival in glioblastoma multiforme: a Surveillance Epidemiology and End Results (SEER) population analysis

ABSTRACT: BACKGROUND: Glioblastoma Multiforme (GBM) is one of the most aggressive primary brain tumors and is associated with a dismal prognosis. The median survival after the primary diagnosis remains poor, even after multimodal treatment approaches. However, a few patients have been reported to have long term survival greater than three years. A number of studies have attempted to define factors capable of predicting long term outcomes in specific patient groups. This article reports the outcomes of a very large group of patients diagnosed with GBM, and analyzes specific prognostic factors known to influence survival in these patients. METHODS: We used the Surveillance, Epidemiology, and End Results (SEER) database of the US National Cancer Institute (NCI) to investigate various patient-related and treatment- related factors that could influence the long term survival in patients diagnosed with glioblastoma. A total of 34,664 patients aged 20 years or older with a diagnosis of GBM during the years 1973 to 2008 were studied. Overall survival outcomes were examined with Kaplan-Meier survival analysis and Cox hazard models. RESULTS: Asian/Pacific Islanders had a better survival compared to the white population (P = <0.001). Patients diagnosed with GBM during the years 2000 to 2008 had a superior survival rate when compared with earlier decades (P = <0 .001). Statistically significant improvements in overall survival were also found for patients who received surgical resections, and adjuvant radiation treatment versus no radiation (P-values <0.001). Young age was also found to be highly predictive of improved overall survival rates when separated into age groups as well as when studied as a continuous variable. CONCLUSIONS: Clinical pretreatment and treatment factors, including young age at diagnosis, Asian/Pacific Islander ethnicity, recent year of diagnosis, surgical resection and the use of adjuvant radiation therapy favorably influence survival in patients diagnosed with glioblastoma. Trial Registration All data were obtained from the United States Surveillance Epidemiology and End Results (SEER) database.     

Evolution of the NANOG pseudogene family in the human and chimpanzee genomes

Background  

The NANOG gene is expressed in mammalian embryonic stem cells where it maintains cellular pluripotency. An unusually large family of pseudogenes arose from it with one unprocessed and ten processed pseudogenes in the human genome. This article compares the NANOG gene and its pseudogenes in the human and chimpanzee genomes and derives an evolutionary history of this pseudogene family.     

Poly(U) binding to ascites cells of the 13762A rat mammary adenocarcinoma: Evidence for a protein receptor on the cell surface

Ascites cells of the 13762 rat mammary adenocarcinoma bind poly(U) in a reaction that is complete within 5 min at 0°C. Poly(U) binding is saturable; the capacity of these cells is 5×10⁷ UMP residues/cell (approx. 2×10⁵ chains/cell). Most [³H]poly(U) bound in the rapid reaction can be recovered in an undergraded state. However, it is rapidly degraded by low concentrations of exogenous pancreatic ribonuclease. The magnitude of binding is independent of temperature and ionic conditions, and is unaffected by metabolic inhibitors or concanavalin A (ConA). Radioactivity presented as [³H]poly(U) tends to co-fractionate with 5′-nucleotidase after homogenization of cells in the media of low ionic strength, but is efficiently released from cells exposed to protein denaturants that effectively fix cellular RNA in situ. Cells pretreated with proteolytic enzymes have sharply reduced capacities to bind poly(U). Autoradiography of cells bearing [³H]poly(U) demonstrates a uniform distribution of radioactivity through the cell population and is consistent with binding to the plasma membrane. These and other results imply that binding of poly(U) to 13762 ascites cells is mediated by protein receptors on the cell surface.     

Relationship of hemolysis buffer structure, pH and ionic strength to spontaneous contour smoothing of isolated erythrocyte membranes

Isolated human erythrocyte membranes crenate when suspended in isotonic medium, but can use MgATP to reduce their net positive curvature, yielding smooth discs and cup forms that eventually undergo endocytosis. An earlier report from this laboratory (Patel, V.P. and Fairbanks, G. (1981) J. Cell Biol. 88, 430-440), has described a phenomenon of ATP-independent shape change in which ghosts prepared by hemolysis and washing in synthetic zwitterionic buffers crenated at 0 degree C, but underwent conversion to smooth discs and cups when warmed in the absence of MgATP. We have further explored the effect of the hemolysis condition on the requirement for ATP in ghost shape change. 25 hemolysis buffers were applied at 10 mM (pH 7.4, 0 degree C). Eight anionic buffers with relatively high ionic strength (e.g., phosphate and diethylmalonic acid (DMA] yielded ghosts requiring ATP for shape change, while two cationic buffers (Bistris and imidazole) and ten synthetic zwitterionic buffers (e.g., Tricine and Hepes) with lower ionic strength produced ghosts that smoothed spontaneously at 30 degrees C. Hemolysis at intermediate ionic strength yielded mixed populations in which spontaneous smoothing was expressed in all-or-none fashion. Maximal ATP-independent shape change was induced by hemolysis at pH 7.3-7.7, while ATP was required after hemolysis at pH less than or equal to 7.1 even when the ionic strength at hemolysis was low. Ghosts requiring ATP could be converted to ATP independence by washing at low ionic strength, but ATP independence could not be reversed readily by washing at high ionic strength. Exposure to low ionic strength at pH greater than 7.1 presumably changes membrane organization in a way that alters the temperature dependence of tensions within the bilayer or skeleton of the composite membrane.