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.

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.

Developments in the understanding of the particle structure of tobraviruses.

Particles of tobraviruses resemble those of tobacco mosaic tobramovirus (TMV) in having helical symmetry and in being rod-shaped. However, isolated tobravirus coat protein and TMV coat protein respond to changes in the ionic strength and pH of the solute in contrasting ways. The types of aggregate formed in solutions of coat protein also differ which may be related to differences in the apparent mechanism of reconstitution of virus particles from isolated protein and RNA. The amino acid sequences of tobravirus and tobramovirus coat proteins have been shown to be similar in some regions known to be important for the structure of TMV particles. These alignments also show that tobravirus proteins are larger than tobramoviral proteins in part because of extra residues at the C-terminus. Tobravirus particles give a signal in proton NMR spectroscopy but TMV particles do not. The signal is caused by segmental mobility of the C-terminal peptide. This difference between TMV and tobraviruses may be related to a property not shared by tobraviruses and TMV and it is therefore speculated that the mobile C-terminal peptide of tobravirus coat proteins may be important in the transmission of tobravirus particles by nematode vectors.

Nuclear magnetic resonance (NMR) microimaging of raspberry fruit: further studies on the origin of the image.

Nuclear magnetic resonance (NMR) micro-images of mature red raspberry (Rubus idaeus L.) fruits and their separated components have been produced under a variety of experimental conditions with the objective of understanding factors which determine image quality in different types of tissue. By varying the delay time between image accumulation sequences it has been shown that water molecules in drupelet surface layers in contact with other drupelets, and in the vascular bundles and traces in the receptacle and drupelets have shorter relaxation times than those in other tissues of the fruit. By performing separate T1 - > and T2 -weighted imaging sequences it was shown that the short relaxation times in the vascular tissue was primarily a T1 effect. This is probably caused by paramagnetic ions because electron paramagnetic resonance (EPR) spectroscopy showed significant amounts of the manganese(n) ion in a spectrum of an aqueous extract of receptacle tissue. The cause of the short relaxation times in the drupelet surface layers is less clear, but we suggest that epicuticular waxes or the suberized cuticular layer of the epidermis might be responsible. The appearance of entire seeds, including the mature embryos, as featureless black regions in the images has been shown to be due to the lower concentration of mobile protons in these structures compared with that in the surrounding mesocarp, and not to differences in relaxation properties of the protons. Consequently, internal detail of the seeds could only be obtained by separating them from the fruit.

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.

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.

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.

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.

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.

Identification of the distribution of sugars in grapes using chemical shift selective NMR microscopy.

Images are presented which show that NMR microscopy can be used to determine the spatial distribution of sugars in grapes. The production of appreciable sugar gradients during the final ripening process was detected in parenchymatous tissues around the seeds, but these gradients disappeared in fully ripened fruit.

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.

The occurrence of copper, iron, zinc and other elements and the nature of some copper and iron complexes in humic substances from municipal refuse disposed of in a landfill.

Municipal refuse was allowed to decompose in a simulated landfill for 20 months. Three different models were studied in which the refuse, in 40 m3 lots, was either compacted or mixed 2:1 with sewage sludge, the latter being studied in both uncompacted and compacted states. At 2, 6, 12 and 20 months, humic substances were extracted from samples with 0.1 M Na2P4O7 and 0.1 M NaOH, and humic acids isolated by precipitation after acidification with HCl. The humic substances were examined by electron paramagnetic resonance (EPR) to determine the free radical content and the nature of some of the metal complexes present. The principal form of copper was present in either a square planar or a tetragonally-distorted octahedral environment, probably coordinated to two nitrogen and two oxygen atoms. Fe3+ was present in at least three different environments. In one, it was probably in a complex with rhombic symmetry; another showed Fe3+ in an axially-symmetric environment, most likely as a ferric porphyrin. No distinctions could be made between the concentrations or forms of metals present in the refuse humic substances as a result of adding sewage sludge, but the additions increased the yield of humic substances, particularly in the uncompacted landfill. Humic substances in the refuse retain metal elements in complexed forms which will restrict their release from the landfill.

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.

Spin trapping of free radicals in homogenates of heart from selenium and vitamin E deficient rats.

The formation of unstable free radical species in homogenates of heart from selenium and/or vitamin E deficient rats has been investigated by electron spin resonance spectroscopy using the spin trap alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone. There was only a small amount of free radical formation by heart from control or selenium deficient animals. However, the amounts and rates of formation of free radicals were significantly higher in animals with vitamin E deficiency and higher still in those with combined selenium and vitamin E deficiency.

Oxygen-induced free radical in wheat roots.

ESR experiments have shown that free radicals are formed in wheat plant roots as a result of exposure to O2. Although the radical(s) has not been positively identified, the nature of the spectra allows simple oxygen-derived radicals, such as O2-, HO2. and OH., to be excluded as possibilities. Adsorption of Cu(II), but not Zn(II) or Cd(II) by the root results in a rapid decay of the radical signal to reach a level of 10% of its original intensity after a few minutes.