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Biomedical subjects

R M Haywood

Publications and source records attributed to R M Haywood.

13 recordsLinked to original sources
PubMed2000

The treatment of early cutaneous capillary haemangiomata (strawberry naevi) with the tunable dye laser.

We have treated 39 early cutaneous capillary haemangiomata, in 24 infants, with the tunable dye laser at a wavelength of 585 nm (SPTL 1b, Candela Corporation, Wayland, MA, USA). The average age at first treatment was 13 weeks. The first signs of involution were seen at 19 weeks of age. Complete resolution of the lesions was seen in 61. 5% of haemangiomata at an average age of 39 weeks. Two haemangiomata did not respond to laser treatment and were treated successfully with intralesional steroid injection. There were no complications of laser treatment. The natural history of the treated haemangiomata was significantly shorter than historical evidence suggests for untreated lesions. Haemangiomata may be treated safely and effectively with the tunable dye laser in the early weeks of life leading to accelerated involution and resolution.

Facial Neoplasms↗
PubMed1999

Treatment of traumatic tattoos with the Nd YAG laser: a series of nine cases.

Inadequate primary skin cleansing for dirt-ingrained skin abrasions can result in disfiguring traumatic tattoos. We present nine cases of traumatic tattoos treated with the Nd YAG laser. In six cases the pigmentation was completely cleared and in three cases minimal pigmentation remained. The Nd YAG laser offers effective late treatment of traumatic tattoos with many advantages over conventional destructive treatment modalities. The best treatment is still immediate debridement and cleaning.

Humans↗
PubMed1999

Ruby laser irradiation (694 nm) of human skin biopsies: assessment by electron spin resonance spectroscopy of free radical production and oxidative stress during laser depilation.

Human skin biopsies (hair-bearing scalp skin and non-hair-bearing breast skin) were treated with t-butylhydroperoxide, irradiated with UV light (UVR) or irradiated with 694 nm ruby laser red light. Free-radical production and oxidative stress were assessed with electron spin resonance spectroscopy (ESR) using the ascorbate radical as a marker. In comparison with both UVR and t-butyl-hydroperoxide (which readily induce the ascorbate radical in hair-bearing and hairless skin), 694 nm red light does not result in the formation of the ascorbate radical in detectable concentrations. Spin-trapping experiments with the spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) showed that while free radicals could be detected after treatment of skin with t-butylhydroperoxide, radicals could not be trapped after laser treatment. Treatment of lasered skin (containing DMPO) with t-butylhydroperoxide produced radical adducts as well as the ascorbate radical, demonstrating that the laser neither depletes endogenous ascorbate nor the preadministered spin trap. It is concluded that 694 nm red light does not induce oxidative stress in human skin in levels comparable either to t-butyl hydroperoxide or UV light.

Cyclic N-Oxides↗
PubMed1999

An infiltration technique for reduction mammaplasty: results in 192 consecutive breasts.

The use of local anaesthetic infiltration with adrenaline is now considered safe in reduction mammaplasty. However, the technique of infiltration by those who support its use is often unclear. Any technique must take account of the neurovascular anatomy of the breast if it is to be effective. We propose the use of a large volume of dilute local anaesthetic (20 ml of 1% lignocaine and 1 mg of adrenaline made up to 400 ml with 0.9% saline) which is placed judiciously in the retroglandular space 15 minutes prior to surgery. The results in 96 consecutive patients (192 breasts) who had an inferior pedicle technique were analysed. The breast complication rate was 9.36% and the patient complication rate 19.79%. Postoperative blood loss ranged from 0 to 305 ml with a mean of 56.03 ml and a median of 50 ml. The described method could be considered a variation of the tumescent technique used in liposuction. The results is an almost bloodless dissection with minimal postoperative blood loss. It should be possible to dispense with the use of drains in most cases.

Adolescent↗
PubMed1995

Detection of aldehydes and their conjugated hydroperoxydiene precursors in thermally-stressed culinary oils and fats: investigations using high resolution proton NMR spectroscopy.

High field (400 and 600 MHz) proton NMR spectroscopy has been employed to investigate the thermally-induced autoxidation of glycerol-bound polyunsaturated fatty acids present in intact culinary frying oils and fats. Heating of these materials at 180 degrees C for periods of 30, 60 and 90 min. generated a variety of peroxidation products, notably aldehydes (alkanals, trans-2-alkenals and alka-2,4-dienals) and their conjugated hydroperoxydiene precursors. Since such aldehydes appear to be absorbed into the systemic circulation from the gut in vivo, the toxicological significance of their production during standard frying practices is discussed.

Aldehydes↗
PubMed1994

Generation of lipid peroxidation products in culinary oils and fats during episodes of thermal stressing: a high field 1H NMR study.

The oxidative deterioration of glycerol-bound polyunsaturated fatty acids (PUFAs) in culinary oils and fats during episodes of heating associated with normal usage (30-90 min at 180 degrees C) has been monitored by high field 1H NMR spectroscopy. Thermal stressing of PUFA-rich culinary oils generated high levels of n-alkanals, trans-2-alkenals, alka-2,4-dienals and 4-hydroxy-trans-2-alkenals via decomposition of their conjugated hydroperoxydiene precursors, whereas only low concentrations of selected aldehydes were produced in oils with a low PUFA content, lard and dripping when subjected to the above heating episodes. Samples of repeatedly used, PUFA-rich culinary oils obtained from restaurants also contained high levels of each class of aldehyde. The dietary, physiological and toxicological ramifications of the results obtained are discussed.

Aldehydes↗
PubMed1993

Radical-induced damage to bovine serum albumin: role of the cysteine residue.

The reactions of cerium(IV) and the hydroxyl radical [generated from iron(ii)/H2O2] with bovine serum albumin (BSA) have been investigated by EPR spin trapping. With the former reagent a protein-derived thiyl radical is selectively generated; this has been characterized via the anisotropic EPR spectra observed on reaction of this radical with the spin trap DMPO. Blocking of the thiol group results in the loss of this species and the detection of a peroxyl radical, believed to be formed by reaction of oxygen with initially-generated, but undetected, carbon-centred radicals from aromatic amino acids. Experiments with a second spin trap (DBNBS) confirm the formation of these carbon-centred species and suggest that damage can be transferred from the thiol group to carbon sites in the protein. A similar transfer pathway can be observed when hydroxyl radicals react with BSA. Further experiments demonstrate that the reverse process can also occur: when hydroxyl radicals react with BSA, the thiol group appears to act as a radical sink and protects the protein from denaturation and fragmentation through the transfer of damage from a carbon site to the thiol group. Thiol-blocked BSA is shown to be more susceptible to damage than the native protein in both direct EPR experiments and enzyme digestion studies. Oxygen has a similar effect, with more rapid fragmentation detected in its presence than its absence.

Cyclic N-Oxides↗
PubMed1991

Radical-induced damage to proteins: e.s.r. spin-trapping studies.

The reactions of hydroxyl radicals generated from FeII/H2O2 and CuII/H2O2 redox couples with a variety of proteins (BSA, histones, cytochrome c, lysozyme and protamine) have been investigated by e.s.r. spin trapping. The signals obtained, which are generally anisotropic in nature, characterize the formation of partially-immobilized spin-adducts resulting from attack of the HO. radicals on the protein and subsequent reaction of the protein-derived radicals with the spin trap. Similar spin adducts are observed on incubation of two haem-proteins (haemoglobin and myoglobin) with H2O2 in the absence of added metal ions implying a reaction at the haem centre followed by internal electron transfer reactions. Two strategies have been employed to obtain information about the site(s) of radical damage in these proteins. The first involves the use of a variety of spin traps and in particular DMPO: with this particular trap the broad spectra from largely immobilized radicals show characteristic a(beta-H) values which enable carbon-, oxygen- and sulphur-centred radicals to be distinguished. The second involves the use of enzymatic cleavage of first-formed adducts to release smaller nitroxides, with isotropic spectra, which allow the recognition of beta-proton splittings and hence information about the sites of radical damage to be obtained. These results, which allows backbone and side-chain attack to be distinguished, are in agreement with random attack of the HO. radical on the protein and are in accord with studies carried out on model peptides. In contrast the use of less reactive attacking radicals [N3., .CH(CH3)OH] and oxidising agents (Ce4+) provides evidence for selective attack on these proteins at particular residues.

Amino Acid Sequence↗