Safety, complications and clinical outcome after ultrasound-guided paravertebral catheter insertion for rib fracture analgesia: a single-centre retrospective observational study.

Rib fractures are associated with significant morbidity and mortality. Ultrasound-guided thoracic paravertebral catheter insertion has been described for the management of pain secondary to rib fractures. We conducted a retrospective observational study of all patients with rib fractures who had a paravertebral catheter inserted for analgesia provision over a 4-year period. Data from the Trauma Audit and Research Network were used to compare patients with rib fractures who were managed with paravertebral catheters to those managed with systemic analgesia. A total of 314 consecutive paravertebral catheters were inserted in 290 patients. Five (1.9%) catheters were removed due to ineffective analgesia. Other minor complications occurred in three cases (0.96%). The proportion of rib fracture patients managed with paravertebral catheters increased from 31/200 (15.5%) in the first year of study to 81/168 (48.2%) in the fourth; over this time-period the observed:predicted mortality ratio fell from 1.04 to 0.66. Proportional hazard regression with and without propensity score matching demonstrated a reduction in mortality associated with paravertebral catheter use, but this became statistically non-significant when time-dependent analysis was used. Paravertebral catheters are a safe and effective technique for rib fracture analgesia; however, our data were insufficient to demonstrate any improvement in mortality.

The coordination environment of copper in hair can be altered by treatment products.

OBJECTIVE: To determine whether the coordination environment of copper in hair is affected by the shampoo used. METHODS: Electron paramagnetic resonance (EPR) spectroscopy to discriminate between mixed oxygen/nitrogen and mixed oxygen/sulphur coordination of copper after treatment with two different shampoos. RESULTS: Copper with mixed oxygen/nitrogen coordination could be converted to mixed oxygen/sulphur coordination by treating with the appropriate shampoo, but this was not reversible with the products tested, although copper was removed from hair at very high pH values. CONCLUSION: Commercial hair treatment products can have a profound effect on the copper coordination environment in hair, and this must be taken into account in any attempt to use hair as a health marker.

Determination of the coordination environment of Cu(II) in human hair and its possible relevance to health and hair care treatments.

OBJECTIVE: This paper addresses the question of the coordination environment of copper (II) in hair. METHODS: The research is based on electron paramagnetic resonance (EPR), a spectroscopic technique that detects specifically paramagnetic molecules. Samples were investigated from various male and female subjects of different ages and races. RESULTS: The Cu(II) EPR signals seemed to be a combination of two components in widely differing relative proportions, although both have the relationship g(// )> g(⊥) > 2.0 expected for the unpaired electron in a d(x2-y2) orbital and are thus consistent with square planar or tetragonal symmetry for the Cu(II) ion. With a very few samples, the EPR spectra consisted of a single component, and high quality spectra from these samples are presented for use as standard reference results. In one type of complex, (14) N superhyperfine structure (shfs) was resolved and the spectrum corresponds to Cu coordination to mixed O- and N-containing functional groups, although the number of N atoms cannot be determined with certainty. No (14) N shfs was seen in the spectrum from the other type of complex, and its narrow linewidth excluded the possibility of any. Furthermore, the spectral parameters are inconsistent with coordination of the Cu to four O atoms, but consistent with some S coordinated to the Cu. Large variations between the relative proportions of the two Cu(II) forms were observed with a single healthy subject over a 5-year period, thus suggesting that they are determined by 'environmental' factors, possibly hair treatment processes, rather than being markers for the health of the subject. CONCLUSIONS: EPR spectroscopy is a convenient non-destructive method for determining the Cu coordination environment in hair, and could be used to monitor its response to various types of hair treatment.

Reactions of green and black teas with Cu(II).

Electron paramagnetic resonance (EPR) measurements of the products of reactions between Cu(II) and samples of green and black teas showed spectral components from at least six different Cu(II) complexes with both tea types. Several of these complexes were common to both teas in spite of major differences in their polyphenol compositions. The pH range observed for complex formation, and the total signal intensity in the pH range 4-8, were greatly different from those for the reactions of Cu(II) with (-)-epigallocatechin gallate and gallic acid, the main polyphenols responsible for the free radical signals observed during oxidation of these beverages. Components with spectral parameters similar to those of Cu(II) complexes with theanine, the major amino acid in tea, may contribute to two of the spectra recorded under acidic conditions. However, the initial complexes formed at the lowest pH values investigated are still unidentified. EPR spectra with parameters consistent with Cu(II) polyphenol complexes were only observed under alkaline conditions, thus suggesting that components of tea other than polyphenols might be more important in reactions with copper, and possibly other transition metals, in solutions under physiological conditions.

Evaluation of offspring size-number invariants in 12 species of lizard.

The optimal division of resources into offspring size vs. number is one of the classic problems in life-history evolution. Importantly, models that take into account the discrete nature of resource division at low clutch sizes suggest that the variance in offspring size should decline with increasing clutch size according to an invariant relationship. We tested this prediction in 12 species of lizard with small clutch sizes. Contrary to expectations, not all species showed a negative relationship between variance in offspring size and clutch size, and the pattern significantly deviated from quantitative predictions in five of the 12 species. We suggest that the main limitation of current size-number models for small clutch sizes is that they rely on assumptions of hierarchical allocation strategies with independence between allocation decisions. Indeed, selection may favour alternative mechanisms of reproductive allocation that avoid suboptimal allocation imposed by the indivisible fraction at low clutch sizes.

Free radical processes in green tea polyphenols (GTP) investigated by electron paramagnetic resonance (EPR) spectroscopy.

This chapter reviews the current status of research on investigations of the free radical chemistry of green tea and its constituent polyphenols (GTP). It is based on the use of electron paramagnetic resonance (EPR) spectroscopy, and also includes a section on practical aspects of the technique, which should be of value to readers who are unfamiliar with the detailed operation of EPR. The free radical chemistry of GTP is important, because many of their antioxidant functions involve reactions with O(2)-derived free radicals, and the products of such reactions are themselves generally free radicals. The stability of these products and their abilities to participate in subsequent reactions may have considerable bearing on their biological function. These are also discussed briefly along with the authors' views of future investigations which would appear to be valuable for this topic.

Free radicals in wheat flour change during storage in air and are influenced by the presence of ozone during the growing season.

Electron paramagnetic resonance (EPR) spectra of wheat flour show components from Fe(III), Mn(II) and free radicals (FR). The metal signals were higher in the samples from the stressed plants, and reflected the higher total levels of these elements determined analytically. They remained essentially constant throughout the experiment, but the FR signal increased progressively with time over a period of 4-6 months after milling, after which it reached a maximum. The rate of increase in the FR signal during this period was considerably higher in the flour from plants that had been exposed to elevated ozone levels.

Infection of leaves of Arabidopsis thaliana by Botrytis cinerea: changes in ascorbic acid, free radicals and lipid peroxidation products.

Infection of leaves of Arabidopsis thaliana with conidial suspensions of the necrotrophic pathogen Botrytis cinerea resulted in a large decrease in the level of ascorbic acid and increases in intensity of a single-peak free radical and Fe(III) (g=4.27) signals in electron paramagnetic resonance (EPR) spectra. These changes were not confined to the spreading lesions or associated areas of chlorosis, but extended to other apparently healthy tissues in the infected leaves. They are, therefore, consistent with the existence of high levels of oxidative stress being generated as a result of the infection process. The expected accompanying increases in levels of the aldehydic products of lipid peroxidation, malondialdehyde (MDA) and 4-hydroxy-2-nonenal (4-HNE), were not observed, and in the case of MDA the levels in tissue from infected plants were appreciably lower than in the healthy controls. These last findings are surprising and demonstrate a difference in the response of A. thaliana to infection with B. cinerea compared with tissues from other plant families studied previously.

Botrytis cinerea induces the formation of free radicals in fruits of Capsicum annuum at positions remote from the site of infection.

Free radical adducts of the spin trap alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone have been observed by electron paramagnetic resonance spectroscopy in detached fruits of Capsicum annuum investigated 5 days after infection with Botrytis cinerea. The spectra of these adducts were at a maximum within the soft rot lesion, but they could also be detected at distances up to 50 mm from the edge of the lesion in samples following main vascular bundles. At distances greater than 40 mm, the spectrum of the ascorbate radical was also seen, and at greater distances from the lesion it was the only radical detected. With samples taken from parenchyma tissue adjacent to the vascular bundles there was little adduct formation and the ascorbate radical could be detected, albeit with reduced intensity compared to healthy tissue, at distances as small as 10 mm from the edge of the lesion. This observation of chemical changes at considerable distances from the infected tissue is in contrast to previous observations on the behaviour of other markers of oxidative stress (e.g., 4-hydroxynonenal, malondialdehyde, single-peak free radical, and Fe(III) (g = 4.27) electron paramagnetic resonance signals), where their levels decreased rapidly outside of the soft rot.

Stable free radicals in ozone-damaged wheat leaves.

Chlorophyll fluorescence measurements were performed on attached leaves of wheat plants (Triticum aestivum L. cv. Nandu) that were exposed to ambient air and to air supplemented with 80 and 120 nmol mol-1 ozone. Decreases in the "current photochemical capacity" were observed that were dependent on both the ozone concentration and duration of exposure. Electron paramagnetic resonance (EPR) spectra on freeze-dried samples from the same batches of plants showed the presence of an unidentified stable free radical, whose spectra had similarities to that of the ubisemiquinone radical. The intensity of this radical signal increased with the duration of ozone exposure in leaves that received an additional 120 nmol mol-1 ozone. In contrast, with exposure to air with 80 nmol mol-1 added ozone, there was little if any change in free radical signal intensity over the 4 week period of the experiment. The increase in intensity of the EPR signal occurred later than the chlorophyll fluorescence changes, which suggests that it is associated with permanent leaf damage.

Markers for oxidative stress associated with soft rots in French beans (Phaseolus vulgaris) infected by Botrytis cinerea.

The role of active oxygen species has been studied in spreading soft-rot lesions caused by the necrotrophic fungal pathogen Botrytis cinerea Pers.:Fr. in leaves of four genotypes of French bean (Phaseolus vulgaris L.). Large increases were observed for the aldehydic end-products of oxidative damage, malondialdehyde and 4-hydroxy-2-nonenal, as a result of infection in each of the genotypes studied. Similar increases were found in a stable free radical and g=4.27 Fe(III) signals, but not Mn(II) signals, in electron paramagnetic resonance spectra. These changes were accompanied by large decreases in ascorbic acid levels, with changes in the antioxidant glutathione being genotype dependent.

Synthesis of alpha-substituted beta-amino acids using pseudoephedrine as a chiral auxiliary.

[reaction: see text] beta-Amino acids are becoming increasingly attractive as intermediates in the synthesis of a variety of molecular structures. However, few methods are available for the synthesis of alpha-substituted beta-amino acids that are both readily scalable and highly stereoselective. Herein we report a new method for synthesizing alpha-substituted beta-amino acids that satisfies both of these requirements using enantiomerically pure pseudoephedrine as a chiral auxiliary.

Non-destructive visualisation in three dimensions of freezing events in flowers of blackcurrant (Ribes nigrum L.) using spin-echo NMR microscopy.

Flowers of blackcurrant (Ribes nigrum L.) were subjected to freezing stress in vivo, and the resulting damage examined in three dimensions using a spin-echo nuclear magnetic resonance imaging sequence. Increased signal intensity was detected in the damaged flowers, particularly at the base of the style, in T2-weighted images. This is thought to be the result of intracellular freezing, which causes membrane damage and leakage of cellular contents. It is proposed that this represents the main site of damage within the flowers. The imaging of flowers of differing developmental ages showed larger increases in signal from fully open flowers after freezing damage compared with those in the initial stages of bud, suggesting that the enclosed nature of the flower buds may have a protective effect on the sensitive stylar base. The use of three-dimensional nuclear magnetic resonance imaging provides a rapid and effective means for the visualisation of freezing events within floral tissues; the effective resolution of the images enables greater accuracy and clarity in interpretation than hitherto possible in two dimensions.

High field NMR microscopic imaging of cultivated strawberry fruit.

The experimental conditions required for discrimination of various types of tissue in fruits of cultivated strawberry (Fragaria x Ananassa) at high fields (ca. 7 T) have been investigated. In marked contrast to soft fruits of other species, from which informative images have been derived at high fields using a variety of pulse sequences and acquisition parameters, appreciable image intensities from parenchymal and vascular tissues in healthy strawberry fruits were obtained only with a spin-echo imaging sequence using large sweep widths (ca. 100,000 Hz), and consequently small values for TE ( < 5 ms), indicating predominantly short T2 values for these tissues. Damage caused by infection by the fungal pathogen Botrytis cinerea is readily seen as a result of a large increase in T2 in the infected tissue, whereas ripening processes appear to be characterized primarily by small variations in the T2-weighted contrast and in the relative magnitudes of T1 between vascular and parenchymal tissue. In addition, it was possible selectively to enhance the contributions to images from the achenes ("seeds") by using very short relaxation delays, thereby enhancing T1-dominated contrast mechanisms.

Evaluation of the allergic/irritant potential of air pollutants: detection of proteins modified by volatile organic compounds from oilseed rape (Brassica napus ssp. oleifera) using electrospray ionization-mass spectrometry.

BACKGROUND: Upward trends in allergy and asthma rates have been reported in most western societies, including the UK, where around 15-20% of the population now suffer from allergy or asthma. Scientific proof of the causes of these increases relies on accurate assessment of exposure and standardized diagnostic tests, such as for specific IgE in blood serum and skin testing. For many air pollutants it has proven difficult to assess an individual's exposure outside an occupational environment and reliable test development is hampered by not knowing whether an allergic or irritant mechanism is involved. These problems are particularly evident in the controversial issue of whether airborne releases from oilseed rape can cause health effects. OBJECTIVE: To develop a method for evaluating the allergic/irritant potential of air pollutants and to assess whether the volatile organic compounds emitted by oilseed rape have this potential. METHODS: Proteins were exposed in vitro to volatile organic compounds emitted by oilseed rape. Electrospray ionization-mass spectrometry was used to detect any resultant protein modifications. RESULTS: Dimethyl disulphide, thiocyanic acid methyl ester and 2-methyl-propanenitrile were able to modify human proteins. In addition, two isothiocyanates which can be emitted by damaged oilseed rape also have this ability. The major products emitted by undamaged oilseed rape, terpenes, a sesquiterpene and a terpene alcohol did not have this property, but the possible role of their oxidized products is discussed. CONCLUSION: Some of the volatile organic compounds emitted by oilseed rape have the potential to be allergens/irritants. Standardized modified proteins produced by this method should prove useful for biomonitoring human exposure in molecular epidemiological studies as well as in diagnostic tests. This method should find further application in investigations into the possible health effects of other environmental pollutants.

The use of quantified maximum entropy methods for optimising information from electron paramagnetic resonance spectroscopy.

A quantified maximum entropy method is applied to the optimisation of analytical information from EPR spectra of free radicals. Statistically meaningful errors are produced for the positions and intensities of all spectral peaks and considerable improvements in sensitivity compared with conventional spectral enhancement procedures are obtained with measurements of the intensities of spectra of known radicals.

The vascular architecture of the fruit receptacle of red raspberry determined by 3D NMR microscopy and surface-rendering techniques.

The three-dimensional structure of the vascular system in tht fruit receptacle of red raspberry was determined using NMR microscopy in combination with computer techniques which highlight the surfaces of specific tissue types. The surface-rendering technique is particularly valuable in situations, where there are large differences in image characteristics between the tissue of interest and the rest of the specimen, and thus ideal for the delineation of ilic vascular tissue in the raspberry receptacle. This was shown to consist of a conical network of bundles with a spiral pattern of gaps; tht carpellury traces emereed from the proximal end of each gap. The inner xylem and outer phloem tissues each appeared as a pair of fused columns in the surface-rendered images, and each carpellary trace had a separate supply from the xyiern and phloem.

A mobile element on a virus particle surface identified by nuclear magnetic resonance spectroscopy.

The presence of a mobile element in the coat protein of pepper ringspot tobravirus (PRV) has been established by 1H n.m.r. spectroscopy; two-dimensional correlation spectroscopy (COSY) measurements show that this element consists of alanine, asparagine, glycine, proline, serine and threonine only. By reference to the amino acid sequence of the coat protein, it is concluded that the mobile element is associated with the C-terminal region and consists of between 11 and 38 residues.