Overall symptom severity as a patient-reported outcome measure for chronic rhinosinusitis: what it reflects and how to measure it.

BACKGROUND: The objective of this study was to identify how - and to what extent - overall symptom severity (OSS) score reflects individual chronic rhinosinusitis (CRS) symptoms and whether it can be measured using alternatives to the standard visual analog scale (VAS). METHODS: CRS patients from four sites across three continents rated their OSS scores, severities of nasal obstruction, nasal drainage, decreased sense of smell, facial pain/pressure and sleep disturbance using a standard VAS, VAS with labeled tick marks at every 1 centimeter, and by writing down their OSS on a scale of 0 - 100 (which was divided by 10), all of which lead to severity scores ranging from 0 - 10 in 0.1 intervals. Quality of life was measured using the SNOT-22 and EQ-5D VAS. RESULTS: In 311 CRS patients, OSS score was significantly correlated with SNOT-22 and EQ-5D VAS. OSS score was most greatly associated with the mean of all individual symptom severity scores. From individual CRS symptoms, OSS was most greatly associated with nasal obstruction followed by nasal drainage and facial pain/pressure severities. These results held true for participants with and without nasal polyps. Measurement of OSS and individual symptom severity scores using a standard VAS, tick-marked VAS, and write-in option had near-perfect consistency. CONCLUSIONS: We demonstrate for the first time that OSS largely reflects the mean of individual CRS symptom severities, although OSS is=== most weighted by nasal obstruction severity. OSS and individual symptom severity scores can be measured using a standard VAS, tick-marked VAS or write-in prompt with near-perfect consistency.

Implication of Major Adverse Postoperative Events and Myocardial Injury on Disability and Survival: A Planned Subanalysis of the ENIGMA-II Trial.

BACKGROUND: Globally, >300 million patients have surgery annually, and ≤20% experience adverse postoperative events. We studied the impact of both cardiac and noncardiac adverse events on 1-year disability-free survival after noncardiac surgery. METHODS: We used the study cohort from the Evaluation of Nitrous oxide in Gas Mixture of Anesthesia (ENIGMA-II) trial, an international randomized trial of 6992 noncardiac surgical patients. All were ≥45 years of age and had moderate to high cardiac risk. The primary outcome was mortality within 1 postoperative year. We defined 4 separate types of postoperative adverse events. Major adverse cardiac events (MACEs) included myocardial infarction (MI), cardiac arrest, and myocardial revascularization with or without troponin elevation. MI was defined using the third Universal Definition and was blindly adjudicated. A second cohort consisted of patients with isolated troponin increases who did not meet the definition for MI. We also considered a cohort of patients who experienced major adverse postoperative events (MAPEs), including unplanned admission to intensive care, prolonged mechanical ventilation, wound infection, pulmonary embolism, and stroke. From this cohort, we identified a group without troponin elevation and another with troponin elevation that was not judged to be an MI. Multivariable Cox proportional hazard models for death at 1 year and assessments of proportionality of hazard functions were performed and expressed as an adjusted hazard ratio (aHR) and 95% confidence intervals (CIs). RESULTS: MACEs were observed in 469 patients, and another 754 patients had isolated troponin increases. MAPEs were observed in 631 patients. Compared with control patients, patients with a MACE were at increased risk of mortality (aHR, 3.36 [95% CI, 2.55-4.46]), similar to patients who suffered a MAPE without troponin elevation (n = 501) (aHR, 2.98 [95% CI, 2.26-3.92]). Patients who suffered a MAPE with troponin elevation but without MI had the highest risk of death (n = 116) (aHR, 4.29 [95% CI, 2.89-6.36]). These 4 types of adverse events similarly affected 1-year disability-free survival. CONCLUSIONS: MACEs and MAPEs occur at similar frequencies and affect survival to a similar degree. All 3 types of postoperative troponin elevation in this analysis were associated, to varying degrees, with increased risk of death and disability.

A review of occupationally-linked suicide for dentists.

BACKGROUND AND OBJECTIVES: Suicide rates among dentists and a perceived elevated risk for suicide have been debated in the academic literature. It has filtered into the public psyche that dentists have the highest suicide rate of any occupation. The present review seeks support for both protagonist and antagonist positions from multidisciplinary perspectives. Contemporary risk factors and strategies for intervention and the prevention of suicide in dentistry are explored. METHODS: An online database search for articles and reports, with selected target words, was conducted for peer reviewed publications on suicide in the dental profession, and for factors contributing to dentist suicide. Review guidelines from the American Psychological Association were used to clarify concepts, identify where most work was focussed, and to explore the superiority of any approach to the emotive topic over another. RESULTS: Findings suggest the dominant belief that dentists have an elevated risk of suicide may be historically, but not currently, accurate. Although dentists' suicide is trending down, diversity in methodology means no current consensus is possible. Factors found to be influencing dentists' suicide ranged from known occupational stressors, to toxins and substance abuse, and untreated mental health problems. CONCLUSION: The contemporary position in New Zealand shows dentists per sé are not more likely than other health professionals to commit suicide although they may have been in the past. Dentists should be aware of individual susceptibility to burnout and mental health problems. Future directions are outlined to address this including peer intervention, and programmes available for dentists to cope better with risks leading to suicide.

Molecular mimicry mediated by MHC class Ib molecules after infection with gram-negative pathogens.

The development of many autoimmune diseases has been etiologically linked to exposure to infectious agents. For example, a subset of patients with a history of Salmonella infection develop reactive arthritis. The persistence of bacterial antigen in arthritic tissue and the isolation of Salmonella or Yersinia reactive CD8+ T cells from the joints of patients with reactive arthritis support the etiological link between Gram-negative bacterial infection and autoimmune disease. Models proposed to account for the link between infection and autoimmunity include inflammation-induced presentation of cryptic self-epitopes, antigen persistence and molecular mimicry. Several studies support molecular mimicry as a mechanism for the involvement of class II epitopes in infectious disease-induced self-reactivity. Here, we have identified an immunodominant epitope derived from the S. typhimurium GroEL molecule. This epitope is presented by the mouse H2-T23-encoded class Ib molecule Qa-1 and was recognized by CD8+ cytotoxic T lymphocytes induced after natural infection. S. typhimurium-stimulated cytotoxic T lymphocytes recognizing the GroEL epitope cross-reacted with a peptide derived from mouse heat shock protein 60 and recognized stressed macrophages. Our results indicate involvement of MHC class Ib molecules in infection-induced autoimmune recognition and indicate a mechanism for the etiological link between Gram-negative bacterial infection and autoimmunity.

Glycosylphosphatidylinositol anchors of Plasmodium falciparum: molecular characterization and naturally elicited antibody response that may provide immunity to malaria pathogenesis.

Induction of proinflammatory cytokine responses by glycosylphosphatidylinositols (GPIs) of intraerythrocytic Plasmodium falciparum is believed to contribute to malaria pathogenesis. In this study, we purified the GPIs of P. falciparum to homogeneity and determined their structures by biochemical degradations and mass spectrometry. The parasite GPIs differ from those of the host in that they contain palmitic (major) and myristic (minor) acids at C-2 of inositol, predominantly C18:0 and C18:1 at sn-1 and sn-2, respectively, and do not contain additional phosphoethanolamine substitution in their core glycan structures. The purified parasite GPIs can induce tumor necrosis factor alpha release from macrophages. We also report a new finding that adults who have resistance to clinical malaria contain high levels of persistent anti-GPI antibodies, whereas susceptible children lack or have low levels of short-lived antibody response. Individuals who were not exposed to the malaria parasite completely lack anti-GPI antibodies. Absence of a persistent anti-GPI antibody response correlated with malaria-specific anemia and fever, suggesting that anti-GPI antibodies provide protection against clinical malaria. The antibodies are mainly directed against the acylated phosphoinositol portion of GPIs. These results are likely to be valuable in studies aimed at the evaluation of chemically defined structures for toxicity versus immunogenicity with implications for the development of GPI-based therapies or vaccines.

Effects of Small Temperature Differences Detected in Callosal Circuits of the Anterior Cingulate Cortex.

We measured the sensitivity of cortical circuit activity to small differences in local cortical environments by studying how temperature affects the trajectory of epileptiform events (EEs). EEs evoked via blockade of GABA-A receptors were recorded extracellularly from mouse coronal brain slices containing both hemispheres of anterior cingulate cortex synaptically connected by corpus callosum axons. Preferentially illuminating one hemisphere with the microscope condenser produced temperature differences of 0.1 °C between the hemispheres. The relatively warmer hemisphere typically initiated the EEs that then propagated to the contralateral side, demonstrating temperature directed propagation. Severing the callosum following one hour of EEs showed that the warmer hemisphere possessed a higher rate of EE generation. Further experiments implied that intact callosal circuits were required for the increased EE generation in the warmer hemisphere. We propose a hypothesis whereby callosal circuits can amplify differences in respective hemispheric activity, promoting this directionality in seizure propagation.

Natural ligand of mouse CD1d1: cellular glycosylphosphatidylinositol.

Mouse CD1d1, a member of the CD1 family of evolutionarily conserved major histocompatibility antigen-like molecules, controls the differentiation and function of a T lymphocyte subset, NK1+ natural T cells, proposed to regulate immune responses. The CD1d1 crystal structure revealed a large hydrophobic binding site occupied by a ligand of unknown chemical nature. Mass spectrometry and metabolic radiolabeling were used to identify cellular glycosylphosphatidylinositol as a major natural ligand of CD1d1. CD1d1 bound glycosylphosphatidylinositol through its phosphatidylinositol aspect with high affinity. Glycosylphosphatidylinositol or another glycolipid could be a candidate natural ligand for CD1d1-restricted T cells.

A strategy for rapid and efficient DNA sequencing by mass spectrometry.

Two methods of solid-phase Sanger DNA sequencing followed by detection with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry are demonstrated. In one method, sequencing ladders generated on an immobilized synthetic template were resolved up to the 63-mer including the primer. Detection sensitivity and resolution were sufficient for sequence analysis in the given range. This approach is particularly suitable for comparative (diagnostic) DNA sequencing. A second method that has the potential for high throughput de novo DNA sequencing is also presented; it uses immobilized duplex probes with five-base single-stranded overhangs to capture an unknown DNA template serving as primers for Sanger DNA sequencing. The power of mass spectrometry is demonstrated not only by its very high speed, but also by its ability to identify sequences that are not readable using gel electrophoresis.

A novel a-factor-related peptide of Saccharomyces cerevisiae that exits the cell by a Ste6p-independent mechanism.

Many secreted signaling molecules are synthesized as precursors that undergo multiple maturation steps to generate their mature forms. The Saccharomyces cerevisiae mating pheromone a-factor is a C-terminally isoprenylated and carboxylmethylated dodecapeptide that is initially synthesized as a larger precursor containing 36 or 38 amino acids. We have previously shown that the maturation of a-factor occurs by an ordered biogenesis pathway involving 1) three C-terminal modification steps, 2) two N-terminal proteolytic processing events, and 3) a nonclassical export mechanism mediated by the ATP-binding-cassette (ABC) transporter Ste6p. In the present study, we demonstrate that an unexpected and abundant a-factor-related peptide (AFRP) exists in the culture fluid of MATa cells and that its biogenesis is integrally related to that of mature a-factor itself. We show by purification followed by mass spectrometry that AFRP corresponds to the C-terminal 7 amino acids (VFWDPAC) of mature a-factor (YIIKGVFWDPAC), including both the farnesyl- and carboxylmethylcysteine modifications. The formation and export of AFRP displays three striking features. First, we show that AFRP is produced intracellularly and that mutants (ste24 and axl1) that cannot produce mature a-factor due to an N-terminal processing defect are nevertheless normal for AFRP production. Thus, AFRP is not derived from mature a-factor but, instead, from the P1 form of the a-factor precursor. Second, fusion constructs with foreign amino acids substituted for authentic a-factor residues still yield AFRP-sized molecules; however, the composition of these corresponds to the altered residues instead of to AFRP residues. Thus, AFRP may be generated by a sequence-dependent but length-specific proteolytic activity. Third, a-factor and AFRP use distinct cellular machinery for their secretion. Whereas a-factor export is Ste6p-dependent, AFRP is secreted normally even in a ste6 deletion mutant. Thus, AFRP may exit the cell by another ATP-binding-cassette transporter, a different type of transporter altogether, or possibly by diffusion. Taken together, these studies indicate that the biogenesis of AFRP involves novel mechanisms and machinery, distinct from those used to generate mature a-factor. Because AFRP neither stimulates nor inhibits mating or a-factor halo activity, its function remains an intriguing question.

DNA sequence analysis by hybridization with oligonucleotide microchips: MALDI mass spectrometry identification of 5mers contiguously stacked to microchip oligonucleotides.

Matrix-assisted laser desorption ionization mass spectrometry (MALDI MS) has been applied to increase the informational output from DNA sequence analysis. It has been used to analyze DNA by hybridization with microarrays of gel-immobilized oligonucleotides extended with stacked 5mers. In model experiments, a 28 nt long DNA fragment was hybridized with 10 immobilized, overlapping 8mers. Then, in a second round of hybridization DNA-8mer duplexes were hybridized with a mixture of 10 5mers. The stability of the 5mer complex with DNA was increased to raise the melting temperature of the duplex by 10-15 degrees C as a result of stacking interaction with 8mers. Contiguous 13 bp duplexes containing an internal break were formed. MALDI MS identified one or, in some cases, two 5mers contiguously stacked to each DNA-8mer duplex formed on the microchip. Incorporating a mass label into 5mers optimized MALDI MS monitoring. This procedure enabled us to reconstitute the sequence of a model DNA fragment and identify polymorphic nucleotides. The application of MALDI MS identification of contiguously stacked 5mers to increase the length of DNA for sequence analysis is discussed.

Molecular pharmacology of hepsulfam, NSC 3296801: identification of alkylated nucleosides, alkylation site, and site of DNA cross-linking.

We have determined that hepsulfam, in common with its structural homologue busulfan, alkylates both free guanosine and GMP in DNA at the 7 nitrogen. Mass spectral analysis of the products of the reaction of hepsulfam with guanosine has identified the mono- and bis-alkylated guanosine adducts. UV spectrophotometry and mass spectrometry were used to confirm that alkylation occurred at the 7 nitrogen by following the formation of the formamidopyrimidyl form of the hepsulfam-guanosine adduct at high pH. We have also isolated and identified 1-guanyl,7-hydroxyheptane, 1-guanyl,7-sulfamylheptane, and 1,7-bis(guanyl)heptane from in vitro reaction mixtures of hepsulfam and calf thymus DNA. We have isolated bis-(7-formamidopyrimidyldeoxyguanosinyl)-heptane from an enzymatic digest of DNA treated with hepsulfam. Finally, we have found that hepsulfam forms interstrand cross-links at 5'-GXC-3' sites in model oligonucleotides.

Purification of the intestinal receptor for intrinsic factor by affinity chromatography.

The intestinal receptor for the intrinsic factor vitamin B-12 complex has been solubilized and then purified from the guinea pig ileum using a double structured affinity resin comprised of intrinsic factor coupled to vitamin B-12 which, in turn, was covalently linked to Sepharose 4B. The receptor purified approximately 57 000-fold from the crude homogenate, appears to be a homogenous protein which may be composed of two subunits which separated when the preparation was subjected to polyacrylamide disc gel electrophoresis. Ethylenediaminetetraacetic acid induced dissociation of the complex between the purified receptor and intrinsic factor-B-12 could not be reversed by the addition of excess Ca2+, unlike the effect of EDTA with semipurified receptor or crude ileal homogenates. Calcium reversed the EDTA effect only after the mixture was subjected to extensive dialysis suggesting that the chelating agent interacts directly with the receptor protein. Intrinsic factor-vitamin B-12 competively inhibited the binding of intrinsic factor-[57Co] vitamin B-12 to the purified receptor whereas vitamin B-12 free intrinsic factor did not, even at a 100-fold greater concentration.

Mass spectrometric analysis of proteins.

The past year has seen greatly increased acceptance and application of the analytical capabilities of mass spectrometry by the biochemical community. The technique has been used to provide accurate mass determinations of non-covalently bound protein complexes, rapid mapping of molecular weights of altered peptides in protease digests, sequencing by collisional activation in tandem mass spectrometry, characterization of glycosylation and other modifications, and quantitation of peptides used in clinical diagnostics.

Insights into the neurodegenerative process of Alzheimer's disease: a role for mononuclear phagocyte-associated inflammation and neurotoxicity.

Since the first description of Alzheimer's disease (AD) in 1907, significant progress was made into understanding disease pathophysiology. The enormous effort in AD research has translated into the discovery of genetic linkages for disease, into elucidating the structure and function of the etiologic beta-amyloid protein, and into unraveling the seemingly complex neuroimmunological cascade that affects neuronal dysfunction. Although effective therapies do not currently exist, many are being developed. We propose that the neuropathogenesis of AD, in measure, revolves around the immunological activation of glial cells, which in turn leads to alterations in inflammatory neurotoxin production, and ultimately to neuronal injury and death. Elucidating the mechanisms involved in such glial cell immune activation should provide valuable insights into understanding the disease process and in providing effective therapeutics to prevent and/or retard the devastating neurodegeneration that afflicts so many of our elderly.

A metabolic comparison of a pure long-chain triglyceride lipid emulsion (LCT) and various medium-chain triglyceride (MCT)-LCT combination emulsions in dogs.

Two 20% lipid emulsions containing mixtures of long-(LCT) and medium-chain triglycerides (MCT) were compared with a 20% LCT lipid emulsion. Beagles were infused with emulsions containing either 100% LCT, 75% LCT-25% MCT, or 50% LCT-50% MCT. The emulsions were part of a total parenteral nutrition (TPN) regimen that included 10% dextrose and 5.5% amino acids. Basic nutritional parameters as well as elimination kinetics were monitored. Plasma linoleic acid, ketone, lactate, pyruvate, insulin, glucose, and carnitine were analyzed. The 75% LCT-25% MCT emulsion offers little advantage over 100% LCT as a metabolic substrate. The 50% LCT-50% MCT combination proved to be a potentially better caloric source due to rapid elimination kinetics, increased ketone production, lack of deposition, and no interference with linoleic acid metabolism.

Medium-chain-triglyceride lipid emulsion: metabolism and tissue distribution.

The utilization and distribution of radioactively labeled lipid emulsions were evaluated in Sprague-Dawley rats. Animals received one of three lipid emulsions. Group 1 received [14C]medium-chain-triglyceride (MCT) lipid emulsion, group 2 received a 75%:25% (vol:vol) admixture of [14C]MCT: unlabeled long-chain-triglyceride (LCT) lipid emulsion, and group 3 received only [14C]LCT. The radioactive dose appearing in expired carbon dioxide and various body tissues was monitored over a 24-h period. Results indicate that MCT is oxidized more rapidly and completely than in LCT; approximately 90% of the MCT is converted to carbon dioxide with in 24 h compared with 45% for LCT. When MCT and LCT are administered together, the metabolism of MCT is slowed but remains more rapid than that of LCT. Removal of MCT from the blood was more rapid than was removal of LCT, and tissue radioactivity was lower.

Competitive effects of long-chain-triglyceride emulsion on the metabolism of medium-chain-triglyceride emulsions.

This study was conducted to assess the potential metabolic competitive interactions of intravenous medium-chain-triglyceride (MCT) and long-chain-triglyceride (LCT) lipid emulsions. To assess this competition increasing concentrations of LCT emulsion were added to an intravenous dose of MCT emulsion of 3.0 g/kg body wt up to a maximum dose of 3.0 g LCTs/kg body wt. Blood samples were assessed for competitive interactions by analyzing the following metabolites: glucose, insulin, lactate, pyruvate, ketones (acetoacetate, beta-hydroxybutyrate), elimination of triglycerides, and free fatty acids. Evaluation of the data showed a strong competitive interaction between the MCT and LCT emulsions. This competition was evident as soon as LCTs were added to the MCT infusions and appeared to favor LCTs for removal and metabolism over MCTs. This appears to indicate that there is a peripheral, strong affinity site for LCT removal and metabolism and a shared peripheral site and specific visceral site for MCT removal and metabolism.

Fasting plasma amino acids in elderly men.

The fasting amino acid profile in 22 healthy young men aged 25-35 y (group A) was compared with the fasting profile in 21 healthy independent men aged 65-85 y (group B), in 23 orally-fed nursing home men with dementia aged 65-92 y (group C), and in 17 tube-fed nursing home men with dementia aged 65-88 y (group D). Groups B, C, and D had significantly (p less than 0.05) lower levels of methionine and branched-chain amino acids than group A. Methionine was significantly lower in groups C and D than in group B. The ratio of essential to nonessential amino acids was significantly lower in groups B, C, and D than in group A. The data suggest that the intake of essential amino acids may often be suboptimal in both independent and institutionalized elderly men.

Comparison of the elimination of 10 and 20% TRAVAMULSION lipid emulsion from the blood of beagle dogs.

Metabolic utilization of fat emulsions containing 20% lipid and 10% lipid were compared using beagles. The key parameter measured was elimination of the lipid from the bloodstream, which serves as an indication of the emulsion's availability for metabolism. Nonlinear kinetic analysis was used in this determination. Blood concentrations of free fatty acids, phospholipid, and cholesterol were also measured as additional ways of determining emulsion metabolism. The 10 and 20% emulsions appeared to be equivalent in elimination of the caloric substrate triglyceride from the blood stream. Results also showed an adaptation to emulsion infusion over time at both dosages administered (3 and 6 g/kg of body weight). This was indicated by increased elimination capacity and stabilization of each lipid class measured. However, blood concentrations of phospholipid and cholesterol indicate that the 20% emulsion provides a lesser lipid load for the amount of calories administered when compared to an emulsion containing 10% lipid.