Bacterial lipopolysaccharide induces endothelial cells to synthesize a degranulating factor for neutrophils

Enzymes and other factors secreted by degranulating neutrophils (polymorphonuclear leukocytes, PMNs) mediate endothelial injury, thrombosis, and vascular remodeling. In bacteremia and sepsis syndrome and their consequent complications (including acute respiratory distress syndrome and systemic ischemia-reperfusion resulting from septic shock), neutrophil degranulation is an important mechanism of injury. In related studies, we found that human endothelial cells regulate neutrophil degranulation and that inflammatory cytokines induce synthesis of degranulating factors by human endothelial cells. Here we show that lipopolysaccharides (LPS) from gram-negative bacteria were the most potent agonists for release of degranulating activity by endothelial cells when compared to several cytokines and stimulatory factors. LPS also induced the release of degranulating signals for PMNs from a human endothelial cell line, EA.hy 926. Interleukin 8 (IL-8) is synthesized by endothelial and EA.hy 926 cells in response to LPS and induces neutrophil degranulation. However, complementary strategies using receptor desensitization, translation of messenger RNA by Xenopus laevis oocytes, and purification and analysis of factors from conditioned supernatants demonstrated that degranulating factors distinct from IL8 are generated in response to LPS. The characteristics of a partially purified degranulating factor isolated from conditioned supernatants distinguished it from known chemokines and other factors that induce PMN degranulation and are generated by endothelial cells in response to LPS. Thus, cultured human endothelial cells and endothelial cell lines synthesize several unique signaling molecules that can trigger neutrophil granular secretion. If produced in vivo in response to LPS or other pathologic agonists, these degranulating signals may activate PMNs in combination or in sequence, initiating or propagating vascular damage.     

Randomised trial of eradication of Helicobacter pylori before non-steroidal anti-inflammatory drug therapy to prevent peptic ulcers

BACKGROUND: Helicobacter pylori infection is common in patients with peptic ulcers caused by the use of non-steroidal anti-inflammatory drugs (NSAIDs). But the pathogenic role of H pylori in this disease is controversial. We studied the efficacy of eradication of H pylori in the prevention of NSAID-induced peptic ulcers. METHODS: We recruited patients with musculoskeletal pain who required NSAID treatment. None of the patients had previous exposure to NSAID therapy. Patients who had H pylori infection but no pre-existing ulcers on endoscopy were randomly allocated naproxen alone (750 mg daily) for 8 weeks or a 1-week course of triple therapy (bismuth subcitrate 120 mg, tetracycline 500 mg, metronidazole 400 mg, each given orally four times daily) before administration of naproxen (750 mg daily). Endoscopy was repeated after 8 weeks of naproxen treatment or when naproxen treatment was stopped early because of bleeding or intractable dyspepsia. All endoscopic examinations were done by one endoscopist who was unaware of treatment assignment. The primary endpoint was the cumulative rate of gastric and duodenal ulcers. FINDINGS: 202 patients underwent endoscopic screening for enrolment in the trial, and 100 eligible patients were randomly assigned treatment. 92 patients completed the trial (47 in the naproxen group, 45 in the triple-therapy group). At 8 weeks, H pylori had been eradicated from no patients in the naproxen group and 40 (89%) in the triple-therapy group (p < 0.001). 12 (26%) naproxen-group patients developed ulcers: five had ulcer pain and one developed ulcer bleeding. Only three (7%) patients on triple therapy had ulcers, and two of these patients had failure of H pylori eradication (p = 0.01). Thus, 12 (26%) patients with persistent H pylori infection but only one (3%) with successful H pylori eradication developed ulcers with naproxen (p = 0.002). INTERPRETATION: Eradication of H pylori before NSAID therapy reduces the occurrence of NSAID-induced peptic ulcers.     

Thermodynamics of human DNA ligase I trimerization and association with DNA polymerase beta

The interaction between human DNA polymerase beta (pol beta) and DNA ligase I, which appear to be responsible for the gap filling and nick ligation steps in short patch or simple base excision repair, has been examined by affinity chromatography and analytical ultracentrifugation. Domain mapping studies revealed that complex formation is mediated through the non-catalytic N-terminal domain of DNA ligase I and the N-terminal 8-kDa domain of pol beta that interacts with the DNA template and excises 5'-deoxyribose phosphate residue. Intact pol beta, a 39-kDa bi-domain enzyme, undergoes indefinite self-association, forming oligomers of many sizes. The binding sites for self-association reside within the C-terminal 31-kDa domain. DNA ligase I undergoes self-association to form a homotrimer. At temperatures over 18 degreesC, three pol beta monomers attached to the DNA ligase I trimer, forming a stable heterohexamer. In contrast, at lower temperatures (<18 degreesC), pol beta and DNA ligase I formed a stable 1:1 binary complex only. In agreement with the domain mapping studies, the 8-kDa domain of pol beta interacted with DNA ligase I, forming a stable 3:3 complex with DNA ligase I at all temperatures, whereas the 31-kDa domain of pol beta did not. Our results indicate that the association between pol beta and DNA ligase I involves both electrostatic binding and an entropy-driven process. Electrostatic binding dominates the interaction mediated by the 8-kDa domain of pol beta, whereas the entropy-driven aspect of interprotein binding appears to be contributed by the 31-kDa domain.     

The efficacy of reducing agents or antioxidants in blocking the formation of dense cells and irreversibly sickled cells in vitro

We show that N-acetylcysteine (NAC) has the ability to cause statistically significant diminishment in the in vitro formation of irreversibly sickled cells (ISCs) at concentrations greater than 250 micromol/L. Other antioxidants, approved for human use (cysteamine, succimer, dimercaprol), were not efficacious. NAC had the ability to cause statistically significant conversion of ISCs formed in vivo back to the biconcave shape. NAC was also shown to reduce the formation of dense cells and increase the available thiols in beta-actin. We showed that diminishing reduced glutathione (GSH), by treatment with 1-chloro-2,4-dinitrobenzene, resulted in increased dense cells. We conclude the NAC blocks dense cell formation and ISC formation by targeting channels involved in cellular dehydration and beta-actin, respectively. The efficacy of NAC is probably due to its combined antioxidant activity and ability to increase intracellular GSH.     

Genotypic heterogeneity and phenotypic variation among patients with type 2 Gaucher''s disease

Electrophysiological examination of the function of perceptive organs, like eye or cochlea, works up more and more interest in scientists to look for an objective method of vestibular end organ investigation. In many papers authors attempt to estimate the efficiency of vestibular organs after using angular or linear acceleration as stimulus, which required special and expensive apparatus. Papers that described vestibular evoked myogenic potentials (VEMPs) seem to be very promising. In this study an attempt was taken to obtain VEMPs with own modification of stimulus and response register. Preliminary examinations in 14 healthy volunteers were performed. Two subjects with sensorineural deafness on one side and symmetric, normal excitability of vestibular organs and 4 with bilateral hearing loss and unilateral weakness of vestibular excitability were examined. There were also 6 patients with only weakness of vestibular excitability. On the basis of practical observations, there is a possibility that evoked potentials were a result of stimulation of vestibular part of the inner ear--sacculus. The method of the study is objective, simple, secure and comfortable for patients.     

Compensated cirrhosis due to viral hepatitis: using MR imaging to predict clinical progression

OBJECTIVE: The goal of our study was to determine the relative value of multiple MR features in predicting clinical progression of disease in patients with compensated cirrhosis. MATERIALS AND METHODS: The MR examinations of 23 patients with compensated cirrhosis (Child A) were retrospectively reviewed independently by two radiologists and correlated with clinical progression after follow-up of all patients for more than 12 months each (12-87 months: average, 39 months) by the same experienced hepatologist. Clinical progression was defined as an increase of the Child grade or the Pugh score by at least two points (5- to 15-point scale). In the initial MR study of each patient, the following MR findings were assessed by each radiologist independently: volume indexes of the spleen and each segment of the liver (based on three-axis measurements), nodular surface, regenerative nodules, ascites, iron or fat deposition, and varices or collaterals. RESULTS: The volume index of the spleen was the most accurate predictor of clinical progression (p = .001), the next most accurate was the number of sites of varices or collaterals (p = .002), and the third most accurate was the ratio of caudate lobe to right lobe volume index (p = .02). Other MR findings failed to correlate with clinical progression. CONCLUSION: As revealed on MR imaging, the volume index of the spleen, the severity of varices, and the volume index ratio of caudate lobe to right lobe can be used to help predict clinical progression of disease in patients with compensated cirrhosis.     

Skilled iv therapy clinicians' product evaluation of open-ended versus closed-ended valve PICC lines: a cost savings clinical report

The IV therapy clinician team at Florida Hospital has become active product selectors of IV therapy materials for the institution. It is recognized for its expertise, experience, and knowledge in IV therapy. As end users of many IV therapy products, members are well-qualified to act as principal product selectors of these patient care items. These clinicians identified costly problems with the performance of a conventional open-ended peripherally inserted central catheter (PICC) product being used. A market search for a better product was done and the Bard Groshong closed-ended valve PICC (Bard Access Systems, Inc., Salt Lake City, UT) was selected. These PICCs were used for a 6-week trial period. The 58 inserted Groshong closed-ended valve PICCs were compared with the last 58 open-ended PICCs inserted. Greater quality assessment was apparent in its performance. A substantial cost savings of 21% also was achieved by using the Groshong closed-ended valve PICCs. A clinical report comparing these two products was presented to the value analysis committee. The validated superior performance of the Groshong closed-ended valve PICC with the cost savings for the 6-week trial period won the committee's approval and the change was made to the Groshong closed-ended valve PICC.