One-year Results of Health-related and Vision-related Quality of Life After Clear Lens Extraction and Multifocal Intraocular Lens Implantation

PURPOSE

Multifocal intraocular lenses (MIOLs) are effective in treating presbyopia before cataracts develop. This study measured health-related quality of life (HRQoL) and vision-related quality of life (VRQoL) after clear lens extraction (CLE) and MIOL implantation.

DESIGN

Before-and-after study METHODS: Patients were treated in Medilaser Coronaria, CorGroup, Oulu, Finland. HRQoL was measured by a generic 15-dimension (15D) instrument. VRQoL was measured with Visual Function Index-14 (VF-14) questionnaire.

RESULTS

CLE and MIOL implantation was performed in 137 patients. The patient age was 57 ± 6.2 years (mean ± standard deviation), and 58% were women. The near add was 2.1±0.3 diopters (D). The overall HRQoL 15D score increased from 0.938±0.058 to 0.955±0.057 at 6 months (P < .0001 vs baseline) and to 0.948±0.060 at 1 year (P = .02 vs baseline). The VRQoL VF14 score increased from 85.32±15.57 to 96.57±5.07 at 6 months (P < .0001 vs baseline) and to 96.61±6.48 at 1 year (P < .0001 vs baseline). The increase of HRQoL was correlated with the increase of VRQoL (P < .04).

CONCLUSIONS

CLE and MIOL implantation improved HRQoL and VRQoL compared to spectacles in this 1-year follow-up study. Improvement of HRQoL was correlated with VRQoL.

Quantum mechanical reference spectrum simulation for precursors and degradation products of chemicals relevant to the Chemical Weapons Convention

A selection of acidic, alkaline and neutral degradation products relevant to the Chemical Weapons Convention was studied in wide range of pH conditions to determine their spin systems as well as spectral parameters. The pH dependence of chemical shifts and J couplings was parameterized using Henderson-Hasselbalch-based functions using dichloromethane as additional shift reference in TSP-d₄ referenced spectra. The resulting parameters allowed calculation of precise chemical shifts and J coupling constants in arbitrary pH conditions. The validity of the obtained spin system definitions and parameters as a source of quantum mechanically simulated reference data in chemical verification analysis is demonstrated.

Biosynthesis of the Bis-Prenylated Alkaloids Muscoride A and B

Prenylation is a common step in the biosynthesis of many natural products and plays an important role in increasing their structural diversity and enhancing biological activity. Muscoride A is a linear peptide alkaloid that contain two contiguous oxazoles and unusual prenyl groups that protect the amino- and carboxy-termini. Here we identified the 12.7 kb muscoride (mus) biosynthetic gene clusters from Nostoc spp. PCC 7906 and UHCC 0398. The mus biosynthetic gene clusters encode enzymes for the heterocyclization, oxidation, and prenylation of the MusE precursor protein. The mus biosynthetic gene clusters encode two copies of the cyanobactin prenyltransferase, MusF1 and MusF2. The predicted tetrapeptide substrate of MusF1 and MusF2 was synthesized through a novel tandem cyclization route in only eight steps. Biochemical assays demonstrated that MusF1 acts on the carboxy-terminus while MusF2 acts on the amino-terminus of the tetrapeptide substrate. We show that the MusF2 enzyme catalyzes the reverse or forward prenylation of amino-termini from Nostoc spp. PCC 7906 and UHCC 0398, respectively. This finding expands the regiospecific chemical functionality of cyanobactin prenyltransferases and the chemical diversity of the cyanobactin family of natural products to include bis-prenylated polyoxazole linear peptides.

pH-Dependent Piecewise Linear Correlation of 1H,31P Chemical Shifts: Application in NMR Identification of Nerve Agent Metabolites in Urine Samples

The NMR-observable nuclei of the acidic and basic compounds experience pH dependence in chemical shift. This phenomenon can be exploited in NMR titrations to determine p K_a values of compounds, or in pH measurement of solutions using dedicated pH reference compounds. On the other hand, this sensitivity can also cause problems in, for example, metabolomics, where slight changes in pH result in significant difficulties for peak alignment between spectra of set of samples for comparative analysis. In worst case, the pH sensitivity of chemical shifts can prevent unambiguous identification of compounds. Here, we propose an alternative approach for NMR identification of pH-sensitive analytes. The ¹H and X (¹³C, ¹⁵N, ³¹P, ...) chemical shifts in close proximity to the acidic or basic functional group should, when presented as ordered pairs, express piecewise linear correlation with distinct slope, intercept, and range. We have studied the pH dependence of ¹H and ³¹P chemical shifts of the CH₃-P moiety in urinary metabolites of nerve agents sarin, soman and VX using 2D ¹H-³¹P fast-HMQC spectroscopy. The ¹H and ³¹P chemical shifts of these chemicals appear in very narrow range, and due to subtle changes in sample pH the identification on either ¹H or ³¹P chemical shift alone is uncertain. However, if the observed ¹H and ³¹P chemical shifts of the CH₃-P moiety of individual compounds are presented as ordered pairs, they fall into distinct linear spaces, thus, facilitating identification with high confidence.

The effect of low ventilation rate with elevated bioeffluent concentration on work performance, perceived indoor air quality, and health symptoms

The aim of this laboratory experiment was to study the effects of ventilation rate, and related changes in air quality, predominantly bioeffluents, on work performance, perceived indoor air quality, and health symptoms in a typical conditions of modern open-plan office with low material and equipment emissions. In Condition A, outdoor air flow rate of 28.2 l/s person (CO₂ level 540 ppm) was applied and in Condition B, outdoor air flow rate was 2.3 l/s person (CO₂ level 2260 ppm). CO₂ concentration level was used as an indicator of bioeffluents. Performance was measured with seven different tasks which measure different cognitive processes. Thirty-six subjects participated in the experiment. The exposure time was 4 hours. Condition B had a weak negative effect on performance only in the information retrieval tasks. Condition B increased slightly subjective workload and perceived fatigue. No effects on health symptoms were found. The intensity of symptoms was low in both conditions. The experimental condition had an effect on perceived air quality and observed odor intensity only in the beginning of the session. Although the room temperature was controlled in both conditions, the heat was perceived to impair the performance more in Condition B.

NMR chemical shift and J coupling parameterization and quantum mechanical reference spectrum simulation for selected nerve agent degradation products in aqueous conditions

The spectral parameters of selected nerve agent degradation products relevant to the Chemical Weapons Convention, namely, ethyl methylphosphonate, isopropyl methylphosphonate, pinacolyl methylphosphonate and methylphosphonic acid, were studied in wide range of pH conditions and selected temperatures. The pH and temperature dependence of chemical shifts and J couplings was parameterized using Henderson-Hasselbalch-based functions. The obtained parameters allowed calculation of precise chemical shifts and J coupling constants in arbitrary pH conditions and typical measurement temperatures, thus facilitating quantum mechanical simulation of reference spectra in the chosen magnetic field strength for chemical verification. Copyright © 2017 John Wiley & Sons, Ltd.

ME-CAGEBIRDr,X-CPMG-HSQMBC. A phase sensitive, multiplicity edited long range HSQC with absorptive line shapes

ME-CAGEBIRD^r,X-CPMG-HSMBC pulse sequence is a phase sensitive, carbon multiplicity edited 2D-experiment for detecting heteronuclear correlations originating from long-range ¹H, ¹³C-couplings, ⁿJ_CH. The presented method allows measurement of ⁿJ_CH-values as well as is capable of separating different carbon types in subspectra (¹³C/¹³CH₂ and ¹³CH/¹³CH₃) with minimal amount of cross talk i.e. cross peaks from wrong carbon multiplicity. Pure lineshapes and clean subspectra are achieved by utilizing CPMG in polarization transfer period, CRISIS-approach in multiplicity editing period and zero-quantum filtration. The obtained spectral properties together with simple setup of the experiment make ME-CAGEBIRD^r,X-CPMG-HSMBC a useful addition into synthetic organic chemistry oriented NMR-tool collection.

The effect of slightly warm temperature on work performance and comfort in open-plan offices - a laboratory study

The aim of the study was to determine the effect of a temperature of 29°C on performance in tasks involving different cognitive demands and to assess the effect on perceived performance, subjective workload, thermal comfort, perceived working conditions, cognitive fatigue, and somatic symptoms in a laboratory with realistic office environment. A comparison was made with a temperature of 23°C. Performance was measured on the basis of six different tasks that reflect different stages of cognitive performance. Thirty-three students participated in the experiment. The exposure time was 3.5 h in both thermal conditions. Performance was negatively affected by slightly warm temperature in the N-back working memory task. Temperature had no effect on performance in other tasks focusing on psychomotor, working memory, attention, or long-term memory capabilities. Temperature had no effect on perceived performance. However, slightly warm temperature caused concentration difficulties. Throat symptoms were found to increase over time at 29°C, but no temporal change was seen at 23°C. No effect of temperature on other symptoms was found. As expected, the differences in thermal comfort were significant. Women perceived a temperature of 23°C colder than men.

Application of comprehensive NMR-based analysis strategy in annotation, isolation and structure elucidation of low molecular weight metabolites of Ricinus communis seeds

INTRODUCTION

Powder-like extract of Ricinus communis seeds contain a toxic protein, ricin, which has a history of military, criminal and terroristic use. As the detection of ricin in this "terrorist powder" is difficult and time-consuming, related low mass metabolites have been suggested to be useful for screening as biomarkers of ricin.

OBJECTIVE

To apply a comprehensive NMR-based analysis strategy for annotation, isolation and structure elucidation of low molecular weight plant metabolites of Ricinus communis seeds.

METHODOLOGY

The seed extract was prepared with a well-known acetone extraction approach. The common metabolites were annotated from seed extract dissolved in acidic solution using (1)H NMR spectroscopy with spectrum library comparison and standard addition, whereas unconfirmed metabolites were identified using multi-step off-line HPLC-DAD-NMR approach.

RESULTS

In addition to the common plant metabolites, two previously unreported compounds, 1,3-digalactoinositol and ricinyl-alanine, were identified with support of MS analyses.

CONCLUSION

The applied comprehensive NMR-based analysis strategy provided identification of the prominent low molecular weight metabolites with high confidence.

Rapid chemical characterisation of stilbenes in the root bark of Norway spruce by off-line HPLC/DAD-NMR

INTRODUCTION

Stilbenes are plant secondary metabolites that have shown promising and varied biological activities. Stilbenes are presently actively studied for the exploitation of this primary raw material resource, involving the concept of biorefining. Methods for the rapid discovery of new and known stilbene structures from various plant sources are thus keenly sought.

OBJECTIVE

To establish a simple and rapid technique of off-line HPLC with a diode-array detector (DAD) and NMR for the unambiguous structural elucidation of stilbene structures in the root bark of Norway spruce [Picea abies (L.) Karst.].

MATERIAL AND METHODS

The stilbene containing fraction was extracted from the plant bark with an ethanol:water mixture (95:5, v/v) preceded by defatting of hydrophobic compounds with n-hexane using the accelerated solvent extraction technique. A portion of the ethanol-water soluble extract was hydrolysed with β-glucosidase to prepare stilbene aglycones. The extracts were further purified and enriched using a polymeric adsorbent. Stilbene-enriched extracts were directly characterised by off-line HPLC/DAD-NMR in conjunction with HPLC/DAD and HPLC/DAD with electrospray ionisation MS(n).

RESULTS

Trans-isorhapontin and trans-astringin were identified as the major, and trans-piceid as a minor, stilbene glucosides of the bark of roots of Picea abies. Not only stilbene glucosides but also the corresponding stilbene aglycones, such as trans-resveratrol, trans-piceatannol and trans-isorhapontigenin, were rapidly identified from the hydrolysed extract. The acquired heteronuclear single-quantum coherence and heteronuclear multiple bond correlation spectra were used to assign the complete carbon NMR chemical shifts of trans-isorhapontin and trans-astringin without the need of acquiring a (13)C-NMR spectrum.

CONCLUSION

The off-line HPLC/DAD-NMR method is expedient for the unambiguous identication of structurally similar stilbenes in plant extracts.

A set of triple-resonance nuclear magnetic resonance experiments for structural characterization of organophosphorus compounds in mixture samples

The (1)H, (13)C correlation NMR spectroscopy utilizes J(CH) couplings in molecules, and provides important structural information from small organic molecules in the form of carbon chemical shifts and carbon-proton connectivities. The full potential of the (1)H, (13)C correlation NMR spectroscopy has not been realized in the Chemical Weapons Convention (CWC) related verification analyses due to the sample matrix, which usually contains a high amount of non-related compounds obscuring the correlations of the relevant compounds. Here, the results of the application of (1)H, (13)C, (31)P triple-resonance NMR spectroscopy in characterization of OP compounds related to the CWC are presented. With a set of two-dimensional triple-resonance experiments the J(HP), J(CH) and J(PC) couplings are utilized to map the connectivities of the atoms in OP compounds and to extract the carbon chemical shift information. With the use of the proposed pulse sequences the correlations from the OP compounds can be recorded without significant artifacts from the non-OP compound impurities in the sample. Further selectivity of the observed correlations is achieved with the application of phosphorus band-selective pulse in the pulse sequences to assist the analysis of multiple OP compounds in mixture samples. The use of the triple-resonance experiments in the analysis of a complex sample is shown with a test mixture containing typical scheduled OP compounds, including the characteristic degradation products of nerve agents sarin, soman, and VX. The viability of the approach in verification analysis is demonstrated in the analysis of the 30th OPCW Proficiency Test sample.

Quantitative two-dimensional HSQC experiment for high magnetic field NMR spectrometers

The finite RF power available on carbon channel in proton-carbon correlation experiments leads to non-uniform cross peak intensity response across carbon chemical shift range. Several classes of broadband pulses are available that alleviate this problem. Adiabatic pulses provide an excellent magnetization inversion over a large bandwidth, and very recently, novel phase-modulated pulses have been proposed that perform 90 degrees and 180 degrees magnetization rotations with good offset tolerance. Here, we present a study how these broadband pulses (adiabatic and phase-modulated) can improve quantitative application of the heteronuclear single quantum coherence (HSQC) experiment on high magnetic field strength NMR spectrometers. Theoretical and experimental examinations of the quantitative, offset-compensated, CPMG-adjusted HSQC (Q-OCCAHSQC) experiment are presented. The proposed experiment offers a formidable improvement to the offset performance; (13)C offset-dependent standard deviation of the peak intensity was below 6% in range of+/-20 kHz. This covers the carbon chemical shift range of 150 ppm, which contains the protonated carbons excluding the aldehydes, for 22.3 T NMR magnets. A demonstration of the quantitative analysis of a fasting blood plasma sample obtained from a healthy volunteer is given.

Atomic structures of two novel immunoglobulin-like domain pairs in the actin cross-linking protein filamin

Filamins are actin filament cross-linking proteins composed of an N-terminal actin-binding domain and 24 immunoglobulin-like domains (IgFLNs). Filamins interact with numerous proteins, including the cytoplasmic domains of plasma membrane signaling and cell adhesion receptors. Thereby filamins mechanically and functionally link the cell membrane to the cytoskeleton. Most of the interactions have been mapped to the C-terminal IgFLNs 16-24. Similarly, as with the previously known compact domain pair of IgFLNa20-21, the two-domain fragments IgFLNa16-17 and IgFLNa18-19 were more compact in small angle x-ray scattering analysis than would be expected for two independent domains. Solution state NMR structures revealed that the domain packing in IgFLNa18-19 resembles the structure of IgFLNa20-21. In both domain pairs the integrin-binding site is masked, although the details of the domain-domain interaction are partly distinct. The structure of IgFLNa16-17 revealed a new domain packing mode where the adhesion receptor binding site of domain 17 is not masked. Sequence comparison suggests that similar packing of three tandem filamin domain pairs is present throughout the animal kingdom, and we propose that this packing is involved in the regulation of filamin interactions through a mechanosensor mechanism.

1H, 13C and 15N resonance assignments of the human filamin A tandem immunoglobulin-like domains 16-17 and 18-19

Filamins are large actin-binding and cross-linking proteins which act as linkers between the cytoskeleton and various signaling proteins. Filamin A (FLNa) is the most abundant of the three filamin isoforms found in humans. FLNa contains an N-terminal actin-binding domain and 24 immunoglobulin-like (Ig) domains. The Ig domains are responsible for the FLNa dimerization and most of the interactions that FLNa has with numerous other proteins. There are several crystal and solution structures from isolated single Ig domains of filamins in the PDB database, but only few from longer constructs. Here, we present nearly complete chemical shift assignments of FLNa tandem Ig domains 16-17 and 18-19. Chemical shift mapping between FLNa tandem Ig domain 16-17 and isolated domain 17 suggests a novel domain-domain interaction mode.

Solution structure of the first immunoglobulin domain of human myotilin

Myotilin is a 57 kDa actin-binding and -bundling protein that consists of a unique serine-rich amino-terminus, two Ig-domains and a short carboxy-terminus with a PDZ-binding motif. Myotilin localizes in sarcomeric Z-discs, where it interacts with several sarcomeric proteins. Point mutations in myotilin cause muscle disorders morphologically highlighted by sarcomeric disarray and aggregation. The actin-binding and dimerization propensity of myotilin has been mapped to the Ig-domains. Here we present high-resolution structure of the first Ig-domain of myotilin (MyoIg1) determined with solution state NMR spectroscopy. Nearly complete chemical shift assignments of MyoIg1 were achieved despite several missing backbone 1H-15N-HSQC signals. The structure derived from distance and dihedral angle restraints using torsion angle dynamics was further refined using molecular dynamics. The structure of MyoIg1 exhibits I-type Ig-fold. The absence of several backbone 1H-15N-HSQC signals can be explained by conformational exchange taking place at the hydrophobic core of the protein.

Solution structure of the parvulin-type PPIase domain of Staphylococcus aureus PrsA--implications for the catalytic mechanism of parvulins

Background

Staphylococcus aureus is a Gram-positive pathogenic bacterium causing many kinds of infections from mild respiratory tract infections to life-threatening states as sepsis. Recent emergence of S. aureus strains resistant to numerous antibiotics has created a need for new antimicrobial agents and novel drug targets. S. aureus PrsA is a membrane associated extra-cytoplasmic lipoprotein which contains a parvulin-type peptidyl-prolyl cis-trans isomerase domain. PrsA is known to act as an essential folding factor for secreted proteins in Gram-positive bacteria and thus it is a potential target for antimicrobial drugs against S. aureus.

Results

We have solved a high-resolution solution structure of the parvulin-type peptidyl-prolyl cis-trans isomerase domain of S. aureus PrsA (PrsA-PPIase). The results of substrate peptide titrations pinpoint the active site and demonstrate the substrate preference of the enzyme. With detailed NMR spectroscopic investigation of the orientation and tautomeric state of the active site histidines we are able to give further insight into the structure of the catalytic site. NMR relaxation analysis gives information on the dynamic behaviour of PrsA-PPIase.

Conclusion

Detailed structural description of the S. aureus PrsA-PPIase lays the foundation for structure-based design of enzyme inhibitors. The structure resembles hPin1-type parvulins both structurally and regarding substrate preference. Even though a wealth of structural data is available on parvulins, the catalytic mechanism has yet to be resolved. The structure of S. aureus PrsA-PPIase and our findings on the role of the conserved active site histidines help in designing further experiments to solve the detailed catalytic mechanism.

Rapid and accurate processing method for amide proton exchange rate measurement in proteins

Exchange between protein backbone amide hydrogen and water gives relevant information about solvent accessibility and protein secondary structure stability. NMR spectroscopy provides a convenient tool to study these dynamic processes with saturation transfer experiments. Processing of this type of NMR spectra has traditionally required peak integration followed by exponential fitting, which can be tedious with large data sets. We propose here a computer-aided method that applies inverse Laplace transform in the exchange rate measurement. With this approach, the determination of exchange rates can be automated, and reliable results can be acquired rapidly without a need for manual processing.

Screening and Identification of Organophosphorus Compounds Related to the Chemical Weapons Convention with 1D and 2D NMR Spectroscopy

Two-dimensional 1H-31P Fast-HMQC was tested for determination of the presence in low concentrations of organophosphorus compounds related to the Chemical Weapons Convention. This method, based on inverse detection, demonstrated high sensitivity and selectivity. Background signals, such as solvent peaks, are suppressed with good efficiency, and organophosphorus compounds present at a concentration level 1-10 microg/mL can be detected within a few hours. In addition, phosphorus-selective one-dimensional 1H-31P HSQC-TOCSY was applied to produce a complete proton spectrum of selected organophosphorus compound from a sample containing intense background resonances. Application of the methods presented in this paper resulted in considerably improved performance of NMR spectroscopy as a complementary technique for screening as well as identification of chemical warfare agents in environmental samples.

Some aspects of quantitative 2D NMR

We have studied the application of 2D HSQC for quantitative measurements and propose some improvements to the previously published Q-HSQC method. Application of CPMG-INEPT for polarization transfer period suppresses the evolution of J(HH), and thus corrects the shape of the cross-peaks. The better cross-peak shape makes phase correction and integration of the cross-peaks easier. Further, the (13)C resonance offset dependency can have a significant influence to the results. The offset effects can be compensated either by correcting results with a proper coefficient, or using 90 degrees composite (13)C pulses in the pulse sequence. The results show that these modifications improve the applicability of 2D HSQC for quantitative analysis when studying molecules possessing large J(HH) couplings and wide (13)C chemical shift range.

CAGEBIRD: improving the GBIRD filter with a CPMG sequence

An improvement of the GBIRD-filter is presented. The current approach utilizes Carr-Purcell-Meiboom-Gill type pulse train during the BIRD delay. The method enables recording of purely absorptive 1D spectrum using only one isotope editing element. In the current method, the parent signal leakage due to JHH evolution during the BIRD delay is considerably smaller than in the conventional approach. As a consequence, the t1-noise is smaller also in 2D applications, such as GBIRD-filtered HSQC.

Evaluation of protein 15N relaxation times by inverse Laplace transformation

Relaxation times (T1, T2, T1rho) are usually evaluated from exponential decay data by least-squares fitting methods. For this procedure, the integrals or amplitudes of signals must be determined, which can be laborious with large data sets. Moreover, the fitting requires a priori knowledge of the number of exponential components responsible for the decay. We have adapted inverse Laplace transformation (ILT) for the analysis of relaxation data. Exponential components are resolved with ILT to reciprocal space on their corresponding relaxation rate values. The ILT approach was applied to 3D linewidth-resolved 15N HSQC experiments to evaluate 15N T1 and T2 relaxation times of ubiquitin. The resulting spectrum is a true 3D spectrum, where the signals are separated by their 1H and 15N chemical shifts (HSQC correlations) and by their relaxation rate values (R1 or R2). From this spectrum, the relaxation times can be obtained directly with a simple peak-picking procedure.

LR-CAHSQC: an application of a Carr-Purcell-Meiboom-Gill-type sequence to heteronuclear multiple bond correlation spectroscopy

A new pulse sequence, long-range CPMG-adjusted heteronuclear single quantum coherence (LR-CAHSQC), is proposed for the determination of long-range JCH coupling constants from a long-range 1H-13C correlation experiment. The long-range heteronuclear coupling constants can be directly extracted from COSY-type antiphase peak patterns. The current approach utilizes CPMG-sequences for polarization transfer, and thus avoids the evolution of homonuclear JHH couplings, which normally may introduce abnormalities into the cross peak pattern. The differences between LR-CAHSQC and normal LR-HSQC are discussed.

Which factors explain the lower prevalence of atopy amongst farmers' children?

BACKGROUND

The inverse association between farming and atopy in children has been attributed to microbial exposure, especially through livestock. Very little is known about other potential explanatory factors.

OBJECTIVE

To explore potential differences in lifestyle and environmental factors between farmer and non-farmer families, and whether these factors could explain the association between farming and childhood atopy.

METHODS

A cross-sectional study, including 366 farmers' and 344 non-farmers' children in eastern Finland. Information regarding exposure and background characteristics was gathered by a written questionnaire. Atopy was defined as having one or more positive skin prick test reactions (> 3 mm) against the six common aeroallergens.

RESULTS

Regardless of the current farming type, atopy was less frequent among the farmers' children than the non-farmers' children (aOR 0.56, 95% CI 0.40-0.78). Remarkable differences were seen in many lifestyle factors (including diet) between the farmer and non-farmer families, but only a few of the explored factors were associated with atopy. The frequency of current livestock contacts seemed to have an inverse, dose-dependent association with atopy (aOR 0.46, 95% CI 0.22-0.97 for daily vs. no contact). Having lived on a dairy farm in infancy (aOR 0.51, 95% CI 0.28-0.93), or having had cats or dogs in infancy (aOR 0.60, 95% CI 0.42-0.85), decreased the risk of atopy at school age. The inverse association between farming and atopy was not explained by the sociodemographic factors, or by differences in conventional risk factors of atopy. Animal contacts explained partially, but not completely, the association.

CONCLUSION

Higher frequency of animal contacts is one factor, but probably not the only one, explaining the inverse association of farming and atopy in children. The importance of early life exposures may have recently been over-emphasized, and current exposures discounted, when studying the risk factors of childhood atopy.

Application of quantitative artificial neural network analysis to 2D NMR spectra of hydrocarbon mixtures

Understanding relationships between the structure and composition of molecular mixtures and their chemical properties is a main industrial aim. One central field of research is oil chemistry where the key question is how the molecular characteristics of composite hydrocarbon mixtures can be associated with the macroscopic properties of the oil products. Apparently these relationships are complex and often nonlinear and therefore call for advanced spectroscopic techniques. An informative and an increasingly used approach is two-dimensional nuclear magnetic resonance (2D NMR) spectroscopy. In the case of composite hydrocarbons the application of 2D NMR methodologies in a quantitative manner pose many technical difficulties, and, in any case, the resulting spectra contain many overlapping resonances that challenge the analytical work. Here, we present a general methodology, based on quantitative artificial neural network (ANN) analysis, to resolve overlapping information in 2D NMR spectra and to simultaneously assess the relative importance of multiple spectral variables on the sample properties. The results in a set of 2D NMR spectra of oil samples illustrate, first, that use of ANN analysis for quantitative purposes is feasible also in 2D and, second, that this methodology offers an intrinsic opportunity to assess the complex and nonlinear relationships between the molecular composition and sample properties. The presented ANN methodology is not limited to the analysis of NMR spectra but can also be applied in a manner similar to other (multidimensional) spectroscopic data.

Markers of airway inflammation and airway hyperresponsiveness in patients with well-controlled asthma

In steroid-naive asthmatics, airway hyperresponsiveness correlates with noninvasive markers of airway inflammation. Whether this is also true in steroid-treated asthmatics, is unknown. In 31 stable asthmatics (mean age 45.4 yrs, range 22-69; 17 females) taking a median dose of 1,000 microg inhaled corticosteroids (ICS) per day (range 100-3,600 microg x day(-1)), airway responsiveness to the "direct" agent histamine and to the "indirect" agent mannitol, lung function (forced expiratory volume in one second (FEV1), forced vital capacity (FVC), peak expiratory flow (PEF)), exhaled nitric oxide (eNO), and number of inflammatory cells in induced sputum as a percentage of total cell count were measured. Of the 31 subjects, 16 were hyperresponsive to mannitol and 11 to histamine. The dose-response ratio (DRR: % fall in FEV1/cumulative dose) to both challenge tests was correlated (r=0.59, p=0.0004). However, DRR for histamine and DRR for mannitol were not related to basic lung function, eNO, per cent sputum eosinophils and ICS dose. In addition, NO was not related to basic lung function and per cent sputum eosinophils. In clinically well-controlled asthmatics taking inhaled corticosteroids, there is no relationship between markers of airway inflammation (such as exhaled nitric oxide and sputum eosinophils) and airway responsiveness to either direct (histamine) or indirect (mannitol) challenge. Airway hyperresponsiveness in clinically well-controlled asthmatics appears to be independent of eosinophilic airway inflammation.

Stratification of welding fumes and grinding particles in a large factory hall equipped with displacement ventilation

The purpose of the study was to investigate the performance of displacement ventilation in a large factory hall where large components of stainless steel for paper, pulp and chemical industries were manufactured. The performance of displacement ventilation was evaluated in terms of concentration distributions of welding fumes and grinding particles, flow field of the supply air and temperature distributions. Large differences in vertical stratification patterns between hexavalent chromium (Cr(VI)) and other particulate contaminants were observed. The concentration of Cr(VI) was notably lower in the zone of occupancy than in the upper part of the factory hall, whereas the concentrations of total airborne particles and trivalent chromium (Cr(III)) were higher in the occupied zone than in the upper zone. The stratification of Cr(VI) had the same tendency as the air temperature stratification caused by the displacement flow field.

Laboratory protocol for exercise asthma to evaluate salbutamol given by two devices

PURPOSE

As new delivery devices and formulations are being introduced for drugs given by inhalation, there is a need to evaluate their equivalence with old preparations. One way to do this is to investigate their equivalence in protecting from exercise-induced asthma (EIA).

METHODS

We used a protocol for EIA to compare the protective effect of salbutamol delivered by the pressurised metered dose inhaler (pMDI) and the new Diskus dry powder device. Twenty-seven asthmatic subjects with moderately severe EIA completed an exercise test on four separate days at two study centers. Exercise was performed by cycling for 8 min while inhaling dry air (0% RH, 20-24 degrees C). The target workload in W was predicted as (53.76 x predicted FEV1) - 11.07 and 95% of this target was achieved at 4 min of exercise. This target was chosen in order to achieve ventilation between 50 and 60% of predicted maximum in the last 4 min.

RESULTS

There was no significant difference in the workload, ventilation, or heart rate achieved on the study days. The severity of EIA was measured as the % fall in FEV1. EIA severity was similar on the placebo and control day and the coefficient of variation was 19.4%. The mean +/- SD % fall on the control, placebo, salbutamol by Diskus, and pMDI were 42.0% +/- 15, 39.4% +/-17.6, 13.4% +/- 13.2, and 8.5% +/- 13.8, respectively. Salbutamol significantly inhibited the % fall in FEV1 after exercise, and there was no difference between the preparations.

CONCLUSION

The protocol described here is suitable for evaluating equivalence of salbutamol preparations in protecting against EIA and could be used to evaluate the protective effect of other medications.

Predictive markers of asthma exacerbation during stepwise dose reduction of inhaled corticosteroids

To determine predictors for failed reduction of inhaled corticosteroids (ICS), in 50 subjects with well-controlled asthma (age 43.7 [18-69]; 22 males) taking a median dose of 1,000 microg ICS/d (100-3,600 microg/d), ICS were halved every 8 wk. Airway hyperresponsiveness (AHR) to a bronchial provocation test (BPT) with histamine was measured at baseline. AHR to BPT with mannitol, spirometry, exhaled nitric oxide (eNO), and, in 31 subjects, sputum inflammatory cells were measured at baseline and at monthly intervals. Thirty-nine subjects suffered an asthma exacerbation. Seven subjects were successfully weaned off ICS. Using a Kaplan- Meier survival analysis, the significant predictors of a failure of ICS reduction were being hyperresponsive to both histamine and mannitol at baseline (p = 0.039), and being hyperresponsive to mannitol during the dose-reduction phase of the study (p = 0.02). Subjects older than 40 yr of age tended to be at greater risk of ICS reduction failure (p = 0.059). Response to mannitol and percentage sputum eosinophils were significantly greater before a failed ICS reduction than before the last successful ICS reduction, whereas there were no significant differences in symptoms, spirometry, or eNO. These findings suggest that documentation of patient's AHR or sputum eosinophils may be useful in guiding the reduction of ICS doses.

Nasal hyperosmolar challenge with a dry powder of mannitol in patients with allergic rhinitis. Evidence for epithelial cell involvement

BACKGROUND

The responses to airway hyperosmolar challenges probably involve various inflammatory mediators. However, it is not fully understood which cell type/types are the source of these mediators. Potential cell types include mast cell, epithelial cell and the sensory c-fibre nerve cell.

OBJECTIVE

To clarify which cell types are involved with the mediator response to hyperosmolarity in the human airway.

METHODS

Ten healthy subjects, 11 patients with nonactive allergic rhinitis, and nine with active allergic rhinitis were challenged intranasally with mannitol powder, and with sham provocation, on separate days. Symptoms were assessed by visual analogue scales and nasal patency by measuring the nasal peak inspiratory flow (nPIF). Nasal lavage fluid levels of alpha(2)-macroglobulin (an index of plasma extravasation), substance P (an index of sensory nerve cell activation), tryptase (an index of mast cell activation) and 15-hydroxyeicosatetraenoic acid (15-HETE, an index of epithelial cell activation) were analysed.

RESULTS

Immediate, although transient burning was the most prominent symptom in all groups whereas only the patients with active rhinitis experienced a fall in nPIF. Mannitol significantly increased the nasal lavage fluid 15-HETE levels in the allergic patients (P < 0.01 vs the sham challenge), but not in the healthy subjects. The increase in 15-HETE correlated with nasal symptoms for itching (r(s) = 0.65, P = 0.019) and burning (r(s) = 0.72, P = 0.009). Detectable levels of tryptase was found only in five allergic subjects. Lavage levels of substance P and alpha(2)-macroglobulin did not not change.

CONCLUSION

Epithelial cell seems to be involved with the mediator response to airway hyperosmolar challenge. The roles of sensory c-fibre nerve cell and mast cell remained less clear.

Nedocromil sodium inhibits responsiveness to inhaled mannitol in asthmatic subjects

Nedocromil sodium inhibits the response to exercise-induced asthma (EIA). Mannitol given as a powder by inhalation is an osmotic stimulus that identifies EIA. We studied the acute effect of nedocromil on airway responsiveness to mannitol in 24 asthmatic subjects. After a control day, nedocromil (8 mg) or its placebo was administered randomized, double blind, 10 min before a challenge with progressively increasing doses of mannitol. Nedocromil inhibited the response to mannitol and there was a significant increase in the dose of mannitol required to cause a 15% reduction in FEV(1) (PD(15)) after nedocromil 409 (316,503) mg compared with placebo 156 (106,229) mg (p < 0.001). In the presence of nedocromil 12 subjects no longer recorded a 15% decrease in FEV(1) in response to mannitol. The remaining 12 required a significantly greater dose of mannitol to achieve a 15% decrease in FEV(1) after nedocromil. Following nedocromil, a plateau in responsiveness to mannitol was observed in 14 subjects. Nedocromil significantly inhibits the responsiveness to inhaled mannitol in asthmatic subjects.

Determinants of bronchial responsiveness at school age in prematurely born children

The bronchial challenge test using isocapnic hyperventilation of cold air (IHCA) was used to evaluate bronchial responsiveness in 63 offspring of multiple pregnancies when they were 8-15 years old. At birth, 27 (43%) children had had intrauterine growth retardation (IUGR, birth weight <-2 SD, or birth weight difference between twin pairs >1.3 SD). The median birth weight was 2,050 g (range, 800-3, 150), and the median gestational age was 35 weeks (range, 28-38). None of the children had asthma or suffered from asthma-like symptoms. In the interpretation of the IHCA test, a fall of 9% or more in the forced expiratory volume in 1 sec (FEV(1)) was considered as abnormal, and these children were classified as "cold air responders." The number of responders was 16 (25%); their baseline FEV(1)/forced vital capacity ratio (FEV(1)/FVC) and forced expiratory flow between 25-75% FVC (FEF(25-75)), but not FEV(1) were significantly lower than the corresponding values in nonresponders. No differences were found in perinatal or neonatal factors between responders or nonresponders. Eight (30%) of the 27 IUGR and 8 (22%) of the 36 appropriate for gestational age (AGA) children were IHCA responders. In particular, IUGR was not correlated with maximal FEV(1) falls following the IHCA test. Respiratory infections after the neonatal period were equally common in IUGR and AGA children; but infections were associated with subsequent IHCA responsiveness. Adenoidectomy, tonsillectomy, and/or myringotomy had been performed significantly more often in the responders than in the nonresponders. At least one of the above invasive procedures had been performed in 20 (32%) of the children; this group was termed the "ENT (ear, nose, throat) surgery group." Fifty-six percent of the responders, but only 26% of the nonresponders, belonged to the ENT surgery group (P = 0.02). We conclude that intrauterine growth retardation or prematurity is not associated with abnormal cold air responsiveness in the IHCA test.

Responsiveness to mannitol in asthmatic subjects with exercise- and hyperventilation-induced asthma

We investigated airway responsiveness to mannitol, a new hyperosmolar challenge, in persons hyperresponsive to airway drying. We studied 36 asthmatic subjects, 18 to 40 yr of age, responsive to exercise (n = 23) and eucapnic hyperventilation (n = 28) defined by a 10% fall in FEV1. Fifteen subjects performed both challenges. All subjects performed a challenge with dry powder mannitol, encapsulated and delivered via a Dinkihaler until a 15% decrease in FEV1 was documented or a cumulative dose of 635 mg was delivered. All subjects responsive to eucapnic hyperventilation and all but one subject responsive to exercise were responsive to mannitol. Sixty-nine percent of subjects had a positive response to mannitol after less than 155 mg (6 capsules) and 94% less than 320 mg (10 capsules). The provoking dose of mannitol required to cause a 15% fall in FEV1 (PD15) was related to the severity of the response to exercise (Pearson's correlation coefficient [rp] = 0.68, p < 0.01) and eucapnic hyperventilation (rp = 0.68, p < 0.01) in subjects who were not taking inhaled corticosteroids. The mean (+/- SD) maximum percent fall in FEV1 after mannitol was 24.4 +/- 6.2% and recovery to bronchodilator occurred within 10 min in most subjects. The mannitol test is simple, inexpensive, faster to perform than hyperpnea with dry air and could become an office-based test. Further studies are now required to determine the sensitivity of mannitol to identify exercise-induced asthma in a random population.

Effect of cold air on exercise capacity in COPD: increase or decrease?

STUDY OBJECTIVE

To clarify the effect of cold air on exercise capacity in COPD.

DESIGN

Cycle ergometer tests under different environmental conditions.

SETTING

Pulmonary function laboratory and an environmental chamber at a university hospital.

PARTICIPANTS

Eighteen patients with stable COPD; 14 completed the study.

INTERVENTIONS

A preliminary cycle ergometer test followed by two incremental, symptom-limited cycle ergometer tests, one at 24 degrees C and the other at -20 degrees C.

MEASUREMENTS

On the first study day: arterial blood gas analysis, 12 to 15 s maximal voluntary ventilation, maximal expiratory flow-volume curves before and 1 h after inhalation of 80 microg of ipratropium bromide, and diffusion capacity of the lung. During the exercise challenges: spirometric indices, minute ventilation (VE), oxygen consumption (VO2), carbon dioxide production (VCO2), facial skin temperature, and heart rate. The feeling of dyspnea was assessed with a visual analogue scale.

RESULTS

The maximal work load was 87.5+/-7.3 W at -20 degrees C compared with 96.4+/-6.9 W at 24 degrees C (p<0.05). Accordingly, the exercise duration was shorter in the cold. Exercise dyspnea was more severe in the cold at equal work loads. The shortening of exercise duration induced by cold air correlated with the enhancement of exercise dyspnea. Furthermore, cold air cooled the facial skin and induced immediate bronchoconstriction. VE, VO2, VCO2, and heart rate did not differ between the warm and cold challenges.

CONCLUSIONS

Cold air decreases exercise capacity in COPD, probably by increasing exercise dyspnea.

Facial cooling, but not nasal breathing of cold air, induces bronchoconstriction: a study in asthmatic and healthy subjects

Reflex-mediated bronchoconstriction in cold climates may be more important than it has previously been thought. This issue has seldom been studied using physiological methods. We wanted to investigate, using physiological methods, what triggers the bronchoconstriction occurring at cold ambient temperature during resting nasal ventilation: cooling of the skin of the face or cooling of the nasal cavity. Three experiments were carried out in 15 stable asthmatics and 10 healthy volunteers: 1) a whole-body exposure to subfreezing temperature in an environmental chamber, during which the subjects breathed cold air through the nose; 2) a similar exposure to subfreezing temperature except that the subjects now breathed warm air through the mouth from outside the chamber; and 3) nasal breathing of subfreezing air from a heat exchanger whilst the subjects sat at room temperature. Spirometric values and facial skin temperature were measured both during and after the exposures. Maximal decrements (means +/- standard errors) of forced expiratory volume in one second (FEV1) in experiments 1, 2 and 3 were: 5.8 +/- 0.8, 5.1 +/- 0.7 and 2.1 +/- 0.5%, respectively (p < 0.001). Only the two experiments in the environmental chamber induced significant bronchoconstriction. All responses were of similar magnitude in the asthmatic and the healthy subjects. The cooling of the skin of the face seems to be the trigger for the bronchoconstriction during resting nasal ventilation at cold ambient temperature both in asthmatic and nonasthmatic subjects.

Effect of whole-body exposure to cold and wind on lung function in asthmatic patients

To assess the effect of subfreezing temperature and wind on lung function in asthmatic patients, an exposure to subfreezing temperature at rest, a moderate exercise challenge at subfreezing temperature, and a similar exercise challenge at room temperature were performed in 19 stable asthmatic subjects in an environmental chamber with an artificial wind. The mean maximal falls in FEV1 were 5.3, 11.7, and 4.8 percent, respectively. The two challenges at subfreezing temperature caused statistically significant changes in FEV1, but the exercise challenge at room temperature had no effect. A large variation in the sensitivity to cold was found. The time courses of the responses varied between the challenges, suggesting at least partially different mechanisms. The results indicate that even moderate exercise can cause severe bronchoconstriction in certain stable asthmatic subjects at climatic conditions similar to the Scandinavian winter. The importance of reflex mechanisms causing bronchoconstriction in physiologic conditions is discussed.

Prevalence and risk factors of genital human papillomavirus (HPV) infections in healthy males: a study on Finnish conscripts

BACKGROUND AND OBJECTIVES

Prevalence of genital human papillomavirus (HPV) infection in the general population is not known. No one test alone can detect all HPV infections.

GOAL OF THIS STUDY

To determine the prevalence of and risk factors for genital human papillomavirus (HPV) infections in healthy males. Voluntary Finnish Army conscripts were examined using peniscopy, cytology (PAP smear) and polymerase chain reaction (PCR) in brush cytology samples.

STUDY DESIGN

A total of 1,471 (99.6%) males completed the questionnaire soliciting their sexual habits, and 432 of them enrolled in the clinical study.

RESULTS

The study group differed from the nonattenders in that they reported more often genitourinary symptoms (P < 0.001), had more casual sexual partners (P = 0.002), and previous STDs (P < 0.001). Classical genital warts were present in 24/432 (5.6%) and papular lesions in 8/432 (1.9%) males. Acetowhite lesions were disclosed in 151/432 (35.0%) cases, of which 61 (14.1%) had peniscopically typical flat HPV lesions. Koilocytes were found in 13/201 (6.5%) PAP smears. HPV DNA was disclosed by PCR in 16.5% (47/285) of the adequate cell smears, and in 7.1% of the males with no peniscopic abnormalities. When considering the men with HPV-positive PCR findings and/or typical peniscopic pattern as HPV-infected (26.2%), many casual partners, previous STDs and no use of condom were significant risk factors for genital HPV infections in the logistic regression analysis.

CONCLUSIONS

The reliable assessment of the prevalence of genital HPV infections in healthy males is not only skewed by the selection of the study group by symptoms and promiscuity, but also by the lack of a universally acceptable screening method. The data confirm sexual promiscuity as the most important risk factor for genital HPV infections.

Niche relations among dung-inhabiting beetles

The whole dung-inhabiting (adult) beetle community living in southern Finland was studied with reference to the seasonal (6 summer months), macrohabitat (open field, half-open pine forest and closed spruce forest) and successional (30 days) gradients. The material comprised 50 coprophagous and 129 carnivorous species, represented by 26,650 and 35,850 individuals, respectively. The most important characteristics of each species are given in an Appendix.In the coprophages the species-abundance relations fitted the lognormal distribution well, but in the carnivores the distribution was strikingly less even. A great number of other differences (see below) apparent between the two trophic groups were explained as the result of a difference in the degree of specialization, apart from the difference in their trophic position: coprophages are microhabitat (dung) and food specialists, while carnivores are microhabitat generalists (and therefore their "critical" niche space was not completely covered in this study).In the coprophages, two important species guilds were observed: the first occurred at the very geginning of the succession (mean position 2.5 days), and consisted mainly of true dung specialists; the second guild contained species with wider utilization along the successional dimension (mean position 6.5 days), and species of more generalist nature (saprophages). The utilization of carnivores along the successional gradient was more continuous, probably because of their more diversified food resources. The total niche width among the coprophages increased from early successional species to species occurring mainly later on, but was more constant in carnivores. The environmental dimensions proved to be totally independent of each other among the carnivores, while the coprophages showed a clear supplementary relationship along them. Among the carnivores, a spherical niche shape dominated, but among the coprophages elongated and disk-liked shapes were also well represented, especially in specialist species. In both groups, a significant positive correlation existed between niche width and dominance, but not between niche width and abundance. It is suggested that the patchy distribution and transient occurrence of suitable microhabitats contributes to the coexistence of many ecologically similar species.