Over or under: hydride attack at the metal versus the coordinated nitrosyl ligand in ferric nitrosyl porphyrins.

Hydride attack at a ferric heme-NO to give an Fe-HNO intermediate is a key step in the global N-cycle. We demonstrate differential reactivity when six- and five-coordinate ferric heme-NO models react with hydride. Although Fe-HNO formation is thermodynamically favored from this reaction, Fe-H formation is kinetically favored for the 5C case.

Clinically orientated classification incorporating shoulder balance for the surgical treatment of adolescent idiopathic scoliosis.

PURPOSE: The achievement of shoulder balance is an important measure of successful scoliosis surgery. No previously described classification system has taken shoulder balance into account. We propose a simple classification system for AIS based on two components which include the curve type and shoulder level. METHODS: Altogether, three curve types have been defined according to the size and location of the curves, each curve pattern is subdivided into type A or B depending on the shoulder level. This classification was tested for interobserver reproducibility and intraobserver reliability. A retrospective analysis of the radiographs of 232 consecutive cases of AIS patients treated surgically between 2005 and 2009 was also performed. RESULTS: Three major types and six subtypes were identified. Type I accounted for 30 %, type II 28 % and type III 42 %. The retrospective analysis showed three patients developed a decompensation that required extension of the fusion. One case developed worsening of shoulder balance requiring further surgery. This classification was tested for interobserver and intraobserver reliability. The mean kappa coefficients for interobserver reproducibility ranged from 0.89 to 0.952, while the mean kappa value for intraobserver reliability was 0.964 indicating a good-to-excellent reliability. CONCLUSIONS: The treatment algorithm guides the spinal surgeon to achieve optimal curve correction and postoperative shoulder balance whilst fusing the smallest number of spinal segments. The high interobserver reproducibility and intraobserver reliability makes it an invaluable tool to describe scoliosis curves in everyday clinical practice.

Demonstration of high-energy 2 omega (526.5 nm) operation on the National Ignition Facility Laser System.

A single beamline of the National Ignition Facility (NIF) has been operated at a wavelength of 526.5 nm (2 omega) by frequency converting the fundamental 1053 nm (1 omega) wavelength with an 18.2 mm thick type-I potassium dihydrogen phosphate (KDP) second-harmonic generator (SHG) crystal. Second-harmonic energies of up to 17.9 kJ were measured at the final optics focal plane with a conversion efficiency of 82%. For a similarly configured 192-beam NIF, this scales to a total 2 omega energy of 3.4 MJ full NIF equivalent (FNE).

The influence of co-morbid IBS and psychological distress on outcomes and quality of life following PPI therapy in patients with gastro-oesophageal reflux disease.

BACKGROUND: A subset of patients with gastro-oesophageal reflux disease (GERD) does not achieve complete symptom resolution with proton pump inhibitor (PPI) therapy. The factors which affect response to PPI therapy in GERD patients remain unclear. AIMS: To determine the prevalence and impact of irritable bowel syndrome (IBS) and psychological distress (PD) on GERD symptoms and disease-specific quality of life (QoL) before and after PPI therapy and to assess the same outcomes before and after PPI therapy in non-erosive reflux disease (NERD) and erosive oesophagitis (EO) GERD patients. METHODS: Patients undergoing oesophago-gastroduodenoscopy (OGD) for heartburn were recruited. Participants completed validated surveys: Digestive Health Symptom Index, Reflux Disease Questionnaire, Quality of Life in Reflux and Dyspepsia and Brief Symptom Inventory (BSI). IBS was defined as >3 Manning criteria and PD as BSI score >63. At OGD, patients were classified as NERD or EO. Patients were treated with rabeprazole 20 mg/day for 8 weeks before completing follow-up surveys. RESULTS: Of 132 GERD patients enrolled, 101 completed the study. The prevalence rates of IBS and PD were 36% and 41%, respectively. IBS independently predicted worse QoL before and after PPI therapy. PD independently predicted worse GERD symptoms and QoL before and after PPI therapy. There were no differences in symptoms or QoL between NERD and EO patients before or after PPI therapy. CONCLUSIONS: IBS and PD impacted GERD symptoms and QoL before and after PPI therapy. Symptoms and QoL before and after PPI therapy were similar in NERD and EO patients.

Oesophageal hypersensitivity is associated with features of psychiatric disorders and the irritable bowel syndrome.

BACKGROUND: Twenty per cent of patients with heartburn do not respond to proton pump inhibitors (PPIs). Many have normal oesophageal acid exposure. We hypothesized that such PPI non-responders have heightened oesophageal sensation, and that oesophageal hypersensitivity is associated with psychiatric features including somatization and anxiety. AIM: To compare oesophageal sensation in subjects with heartburn categorized by response to PPI, and to correlate oesophageal sensation with psychiatric features. METHODS: Twenty-one PPI responders, nine PPI non-responders and 20 healthy volunteers completed questionnaires of psychiatric disorders and gastrointestinal symptoms. Subjects underwent oesophageal sensory testing with acid perfusion and balloon distension. RESULTS: Healthy volunteers displayed higher thresholds for sensation and discomfort from balloon distension than heartburn subjects (sensation P = 0.04, discomfort P = 0.14). Psychiatric disorders were associated with increased intensity of sensation (P = 0.02) and discomfort from acid (P = 0.01). Somatization was associated with increased discomfort from balloon distension (P = 0.006). Features of irritable bowel syndrome were associated with increased sensation and discomfort. CONCLUSIONS: Heartburn subjects tend to have heightened oesophageal sensation, suggesting that oesophageal hypersensitivity may persist despite therapy with PPI. Oesophageal hypersensitivity is associated with features of psychiatric disease and with the irritable bowel syndrome, which might partly explain the aetiology of heartburn symptoms that are refractory to PPI.

National Ignition Facility laser performance status.

The National Ignition Facility (NIF) is the world's largest laser system. It contains a 192 beam neodymium glass laser that is designed to deliver 1.8 MJ at 500 TW at 351 nm in order to achieve energy gain (ignition) in a deuterium-tritium nuclear fusion target. To meet this goal, laser design criteria include the ability to generate pulses of up to 1.8 MJ total energy, with peak power of 500 TW and temporal pulse shapes spanning 2 orders of magnitude at the third harmonic (351 nm or 3omega) of the laser wavelength. The focal-spot fluence distribution of these pulses is carefully controlled, through a combination of special optics in the 1omega (1053 nm) portion of the laser (continuous phase plates), smoothing by spectral dispersion, and the overlapping of multiple beams with orthogonal polarization (polarization smoothing). We report performance qualification tests of the first eight beams of the NIF laser. Measurements are reported at both 1omega and 3omega, both with and without focal-spot conditioning. When scaled to full 192 beam operation, these results demonstrate, to the best of our knowledge for the first time, that the NIF will meet its laser performance design criteria, and that the NIF can simultaneously meet the temporal pulse shaping, focal-spot conditioning, and peak power requirements for two candidate indirect drive ignition designs.

Radiation-driven hydrodynamics of high- hohlraums on the national ignition facility.

The first hohlraum experiments on the National Ignition Facility (NIF) using the initial four laser beams tested radiation temperature limits imposed by plasma filling. For a variety of hohlraum sizes and pulse lengths, the measured x-ray flux shows signatures of filling that coincide with hard x-ray emission from plasma streaming out of the hohlraum. These observations agree with hydrodynamic simulations and with an analytical model that includes hydrodynamic and coronal radiative losses. The modeling predicts radiation temperature limits with full NIF (1.8 MJ), greater, and of longer duration than required for ignition hohlraums.

Importance of quantum tunneling in vacancy-hydrogen complexes in diamond.

Our ab initio calculations of the hyperfine parameters for negatively charged vacancy-hydrogen and nitrogen-vacancy-hydrogen complexes in diamond compare static defect models and models which account for the quantum tunneling behavior of hydrogen. The static models give rise to hyperfine splittings that are inconsistent with the experimental electron paramagnetic resonance data. In contrast, the hyperfine parameters for the quantum dynamical models are in agreement with the experimental observations. We show that the quantum motion of the proton is crucial to the prediction of symmetry and hyperfine constants for two simple defect centers in diamond. Static a priori methods fail for these systems.

Comparison of Prilosec OTC (omeprazole magnesium 20.6 mg) to placebo for 14 days in the treatment of frequent heartburn.

PURPOSE: Consumer surveys have identified an over-the-counter (OTC) medication that provides complete and long-lasting relief of frequent heartburn as an unmet consumer need. The purpose of the two identical studies reported in this paper was to evaluate the safety and effectiveness of 10.3 and 20.6 mg omeprazole magnesium, referred to as Ome-Mg 10 and Ome-Mg 20, respectively (equivalent to 10 and 20 mg omeprazole) for the treatment of frequent heartburn administered as a novel 14-day OTC regimen. SUBJECTS AND METHODS: Subjects with frequent heartburn (heartburn two or more days per week) took Ome-Mg 10, Ome-Mg 20, or placebo for 14 consecutive mornings. Statistical analyses compared percentage of subjects with no heartburn 24 h after the first dose, after the last dose (day 14), and percentage of days that subjects were heartburn-free. Nocturnal heartburn and heartburn rated no more than mild were also assessed. RESULTS: Twenty-four hours following the first dose, nearly 50% of subjects receiving Ome-Mg 20 reported no heartburn, and more than 80% receiving Ome-Mg 20 had no more than mild heartburn. Both doses were significantly more effective than placebo on days 1 and 14 for percentage of subjects heartburn-free for 24 h (P < or = 0.003), and across all 14 days for percentage of heartburn-free days (P < 0.001). Ome-Mg 20 was significantly more effective than placebo in preventing nocturnal heartburn across all 14 days (P < 0.001). Ome-Mg was well tolerated. CONCLUSION: These trials demonstrated the safety and effectiveness of a novel 14-day regimen of Ome-Mg 20 in completely preventing heartburn for 24 h establishing it as an excellent self-care treatment for frequent heartburn and supporting the approval of Prilosec OTC.

Dual tachykinin NK1/NK2 antagonist DNK333 inhibits neurokinin A-induced bronchoconstriction in asthma patients.

Inhalation of neurokinin A (NKA) causes bronchoconstriction in patients with asthma. In vitro both tachykinin NK1 and NK2 receptors can mediate airway contraction. In this study the authors examined the effects of a single dose of the dual tachykinin NK1/NK2 receptor antagonist, DNK333, on NKA-induced bronchoconstriction in asthma. A total of 19 male adults with mild asthma completed a randomised, double-blind, placebo-controlled crossover trial. Increasing concentrations of NKA (3.3x10(-9) to 1.0x10(-6) mol x mLP(-1)) were inhaled at 1 and 10 h intervals after a single oral dosing with either DNK333 (100 mg) or a placebo. It was observed that DNK333 did not affect baseline lung function but did protect against NKA-induced bronchoconstriction in those patients. The mean log10 provocative concentration causing a 20% fall in forced expiratory volume in one second for NKA was -5.6 log10 mol x mL(-1) at 1 h after DNK333 treatment and -6.8 log10 mol x mL(-1) after placebo. This was equivalent to a difference of 4.08 doubling doses, which decreased to a difference of 0.90 doubling doses 10 h after treatment. The results shown in this report indicate that DNK333 blocks neurokinin A-induced bronchoconstriction in patients with asthma.

Risk factors for post-ERCP pancreatitis: a prospective, multicenter study.

BACKGROUND: Post-ERCP pancreatitis is poorly understood. The goal of this study was to comprehensively evaluate potential procedure- and patient-related risk factors for post-ERCP pancreatitis over a wide spectrum of centers. METHODS: Consecutive ERCP procedures were prospectively studied at 11 centers (6 private, 5 university). Complications were assessed at 30 days by using established consensus criteria. RESULTS: Pancreatitis occurred after 131 (6.7%) of 1963 consecutive ERCP procedures (mild 70, moderate 55, severe 6). By univariate analysis, 23 of 32 investigated variables were significant. Multivariate risk factors with adjusted odds ratios (OR) were prior ERCP-induced pancreatitis (OR 5.4), suspected sphincter of Oddi dysfunction (OR 2.6), female gender (OR 2.5), normal serum bilirubin (OR 1.9), absence of chronic pancreatitis (OR 1.9), biliary sphincter balloon dilation (OR 4.5), difficult cannulation (OR 3.4), pancreatic sphincterotomy (OR 3.1), and 1 or more injections of contrast into the pancreatic duct (OR 2.7). Small bile duct diameter, sphincter of Oddi manometry, biliary sphincterotomy, and lower ERCP case volume were not multivariate risk factors for pancreatitis, although endoscopists performing on average more than 2 ERCPs per week had significantly greater success at bile duct cannulation (96.5% versus 91.5%, p = 0.0001). Combinations of patient characteristics including female gender, normal serum bilirubin, recurrent abdominal pain, and previous post-ERCP pancreatitis placed patients at increasingly higher risk of pancreatitis, regardless of whether ERCP was diagnostic, manometric, or therapeutic. CONCLUSIONS: Patient-related factors are as important as procedure-related factors in determining risk for post-ERCP pancreatitis. These data emphasize the importance of careful patient selection as well as choice of technique in the avoidance of post-ERCP pancreatitis.

Artificial saliva substitutes and mineral dissolution.

The erosive potentials of a number of commercially available artificial saliva substitutes have been investigated using an in vitro hydroxyapatite powder dissolution assay. Most of the saliva substitutes examined did not show any appreciable erosive potential, although one product resulted in greater mineral dissolution levels. There appeared to be little correlation between pH and mineral dissolution levels for the different saliva substitutes examined. Whilst saliva substitutes may be of assistance in maintaining some physiological function in patients with impaired salivary flow, it is important to choose a product with low erosive potential where the natural dentition is present.

Effect of endothelin receptor antagonist on lung allograft apoptosis and NOSII expression.

BACKGROUND: It is postulated that apoptosis contributes to ischemia-reperfusion graft dysfunction after lung transplantation. The purpose of this study was to determine whether the improvement in lung function that we previously observed with the use of an endothelin-1 (ET-1) receptor antagonist after ischemia-reperfusion injury is associated with a reduction in inducible nitric oxide synthase (NOSII) expression and programmed cell death. METHODS: Left lung canine allotransplantation was performed. Harvested lung blocks were preserved with modified Eurocollins solution and stored at 4 degrees C for 18 to 20 hours. Lung allografts were tested for the expression of NOSII by immunohistochemistry, and extent of apoptosis by terminal dUTP nick end-labeling (TUNEL). Animals blindly received either an intravenous infusion of saline (control) or the ET-1 receptor antagonist (SB209670) (15 microg/kg/min). Infusion began 30 minutes pretransplantation and continued to 6 hours posttransplantation. RESULTS: Immunohistochemical analysis demonstrated significantly stronger NOSII immunostaining in the allografts of the saline control group (36.5%+/-3.6%) compared with native right lungs (6.9%+/-1.3%, p < 0.001) or the ET-receptor antagonist treatment group (9.6%+/-1.4%, p < 0.001). The TUNEL staining revealed a significantly stronger labeling in the allografts of the saline treatment control group (40.7%+/-6.2%) compared with native right lungs (5.0%+/-0.6%, p < 0.005) or the ET receptor antagonist treatment group (14.1%+/-2.8%, p < 0.01). CONCLUSIONS: We conclude that treatment of lung allografts with the ET-1 receptor antagonist SB209670 reduces the area of NOSII expression and the extent of apoptosis, factors known to contribute to the process of prolonged ischemia-reperfusion injury.

Reliability and validity of the digestive health status instrument in samples of community, primary care, and gastroenterology patients.

AIM: We evaluated a previously reported digestive health status instrument in community, primary care, and gastroenterology practice populations. Multiple types of reliability, validity and responsiveness were assessed to determine the performance of the questionnaire. METHODS: Study populations included community, primary care and gastroenterology subjects. Psychometric analyses included internal consistency and test-retest reliability, criterion and construct validity, and responsiveness. RESULTS: Acceptable internal consistency was seen on all scales in all three populations. Test-retest reliability was excellent in a speciality population with reflux disease. Criterion validity was demonstrated by strong correlation of reflux scale scores and results on 24-h pH monitoring. Scale scores varied predictably in those receiving gastrointestinal tract imaging and according to diagnosis, indicating construct validity. The reflux scale and pain index were sensitive to change with treatment for reflux disease. Multi-trait scaling analyses from the community sample revealed a structure equivalent to that reported from a primary care sample. CONCLUSIONS: The reliability and validity of the digestive health status instrument on multiple measures in multiple settings have been demonstrated. The instrument was responsive to change with treatment for reflux disease. The demonstrated robustness attests to the suitability for future studies and clinical application.

Developing an index of restorative dental treatment need.

The process undertaken to establish an initial pilot index for restorative dental treatment is described. Following consultation with a wide range of clinicians and others, an outline framework for the index was developed and comprised three main components: 1. Patient identified need for treatment: the data from the patient perceived need questionnaire were inconclusive; 2. Complexity of treatment (assessed by clinicians): this was found to be a practical tool capable of being used by a range of dentists. A booklet has been produced which describes the process of using the scoring system; 3. Priority for treatment (assessed by clinicians): three levels of priority were identified; the highest priority was assigned to patients with inherited or developmental defects that justify complex care (eg clefts of the lip and palate). The initial development of the index has had some success in a difficult area. The treatment complexity component is the most developed and may allow both referrers and commissioners of specialist restorative dentistry to determine appropriate use of skilled clinicians' expertise.

Self-reported effectiveness and physician consultation rate in users of over-the-counter histamine-2 receptor antagonists.

OBJECTIVE: Decreased physician visits for dyspepsia were predicted with the histamine-2 receptor antagonists (H2RA) release to over-the-counter (OTC) status. The aim of this study was to examine the presentation frequency for dyspeptic complaints before and after the OTC release of the H2RA and the self-reported effectiveness of OTC H2RA. METHODS: Two cross-sectional surveys were used in a community sample. The patients comprised a random age- and sex-stratified sample of 1600 ambulatory adults in 1993 and 1800 in 1997. Self-report, valid mail surveys gathered information on healthcare seeking and gastrointestinal symptoms in 1993 and 1997 and antisecretory use in 1997. RESULTS: Presentation frequency for dyspepsia was 22% in 1993 versus 23.5% in 1997. Only 16% of chronic users of the OTC H2RA obtained complete relief of symptomatic episodes. Use of an OTC H2RA was highly associated with presentation to a physician in the past year. CONCLUSIONS: OTC H2RA infrequently provided the complete relief desired by patients. Presentation frequency to physicians for dyspeptic complaints did not change with availability of H2RA OTC.

A randomized, controlled trial of interactive, multimedia software for patient colonoscopy education.

The purpose of our study was to assess the effectiveness of computer-assisted instruction (CAI) in patients having colonoscopies. We conducted a randomized, controlled trial in large, multispecialty clinic. Eighty-six patients were referred for colonoscopies. The interventions were standard education versus standard education plus CAI, and the outcome measures were anxiety, comprehension, and satisfaction. Computer-assisted instruction had no effect on patients' anxiety. The group receiving CAI demonstrated better overall comprehension (p < 0.001). However, Comprehension of certain aspects of serious complications and appropriate postsedation behavior were unaffected by educational method. Patients in the CAI group were more likely to indicate satisfaction with the amount of information provided when compared with the standard education counterparts (p = 0.001). Overall satisfaction was unaffected by educational method. Computer-assisted instruction for colonoscopy provided better comprehension and greater satisfaction with the adequacy of education than standard education. Computer-assisted instruction helps physicians meet their educational responsibilities with no decrement to the interpersonal aspects of the patient-physician relationship.

Initial validation of a diagnostic questionnaire for gastroesophageal reflux disease.

OBJECTIVES: Brief, reliable, and valid self-administered questionnaires could facilitate the diagnosis of gastroesophageal reflux disease in primary care. We report the development and validation of such an instrument. METHODS: Content validity was informed by literature review, expert opinion, and cognitive interviewing of 50 patients resulting in a 22-item survey. For psychometric analyses, primary care patients completed the new questionnaire at enrollment and at intervals ranging from 3 days to 3 wk. Multitrait scaling, test-retest reliability, and responsiveness were assessed. Predictive validity analyses of all scales and items used specialty physician diagnosis as the "gold standard." RESULTS: Iterative factor analyses yielded three scales of four items each including heartburn, acid regurgitation, and dyspepsia. Multitrait scaling criteria including internal consistency, item interval consistency, and item discrimination were 100% satisfied. Test-retest reliability was high in those reporting stable symptoms. Scale scores significantly changed in those reporting a global change. Regressing specialty physician diagnosis on the three scales revealed significant effects for two scales (heartburn and regurgitation). Combining the two significant scales enhanced the strength of the model. Symptom response to self-directed treatment with nonprescription antisecretory medications was highly predictive of the diagnosis also, although the item demonstrated poor validity and reliability. CONCLUSIONS: A brief, simple 12-item questionnaire demonstrated validity and reliability and seemed to be responsive to change for reflux and dyspeptic symptoms.

The provision of dental implants in the National Health Service Hospital dental services--a national questionnaire.

OBJECTIVE: To assess the activity of consultants in restorative dentistry in the United Kingdom in the provision of osseointegrated dental implants within the National Health Service Hospital service and to evaluate their attitudes concerning the relevant medical and oral factors considered in patient selection for implant treatment. DESIGN/SETTING: Anonymous postal questionnaire in the United Kingdom. SUBJECTS: Consultants in restorative dentistry. RESULTS: Out of the sample of 145, 109 consultants (75%) completed the questionnaire in 1999. 54 of the 109 consultants (49.5%) are involved in the provision of osseointegrated implant treatment, treating an average of 29 cases/year (range 2-150). However, over one third of the respondents treated 10 or less cases/year. 89% worked with oral surgeons as an implant team. 68% used Branemark (Nobel Biocare) implants as their main system. The majority of consultants felt that smoking, psychoses and previous irradiation were the most important medical factors that contra-indicated implant retained restorations whilst untreated periodontitis, poor oral hygiene and uncontrolled caries were the most important oral contra-indications. Many centres were experiencing significant problems with the funding of implant treatment with one centre receiving no funding. The implications for patient care and specialist training are discussed. CONCLUSIONS: There is a marked variation in the number of patients treated with endosseous dental implants within the United Kingdom National Health Service hospitals. Many consultants treat 10 or fewer patients each year. In the main, there is agreement about the factors that contra-indicate implant treatment; these are in line with national guidelines.