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N Morley

Publications and source records attributed to N Morley.

14 recordsLinked to original sources
PubMed2006

UVA-induced apoptosis studied by the new apo/necro-Comet-assay which distinguishes viable, apoptotic and necrotic cells.

An adaptation of the Comet-assay was developed which enables the discrimination of viable, apoptotic and necrotic single cells by use of the common Annexin-V staining and a dye exclusion test on the cells already embedded in agarose gel on glass slides. Membrane integrity (Ethidium-Homodimer exclusion), cellular esterase activity (Calcein blue-AM) as well as translocation of phosphadidyl-serine (Annexin-V) were analysed using these stains. The advantage of the 'apo/necro-Comet-assay' is that the viability status of individual cells can be determined and correlated with the DNA fragmentation pattern (comet) formed by the same cells. Hence, DNA damage can be assessed and correlated with viable cells or cells undergoing early, mid- or late stage apoptosis or necrosis as identified by the staining pattern. The staining was verified using heat and etoposide-induced apoptosis. This technique, among others, was used to study whether apoptotic fragmentation interferes with repair kinetics measured with the comet assay following UVA exposure (doses up to 1,280 kJ/m(2)) in the cultured human keratinocytes (HaCaT). Therefore, a time course of apoptotic events (phosphatidyl translocation and TUNEL fragmentation) was established and correlated to the DNA fragmentation in the comet-assay. Apoptotic cells were detected more than 8 h later. The combined three-colour staining method with the comet assay showed that there was no significant interference of DNA repair by apoptotic fragmentation processes since DNA repair was almost completed before the onset of apoptotic fragmentation. The apo/necro-Comet-assay reduces the general problem of false-positive results in genotoxicity tests using the Comet-assay.

Annexin A5↗
PubMed2003

N-acetyl-L-cysteine prevents DNA damage induced by UVA, UVB and visible radiation in human fibroblasts.

The thiol N-acetyl-L-cysteine (NAC) is a source of cysteine for the synthesis of the endogenous antioxidant glutathione (GSH) which is depleted by ultraviolet radiation. It is also associated with the scavenging of reactive oxygen species (ROS). In this study the effects of NAC were examined in cultured human fibroblasts during prolonged exposure to ultraviolet B (UVB), ultraviolet A (UVA) and visible irradiation (280-700 nm), delivered by a 150 W xenon-arc lamp. The alkaline comet assay was used to assess the DNA damage in individual cells. It was found that incubating skin and lung fibroblasts at 37 degrees C for 1 h with an optimal 6 mM NAC supplement prior to light exposure, significantly reduced the level of DNA damage in both cell types, however, the skin fibroblasts were less sensitive to xenon-arc lamp irradiation than lung fibroblasts. NAC incubation resulted in an initial delay in DNA damage when the cells were irradiated. There was also a significant reduction in the overall levels of DNA damage observed with continued irradiation. NAC significantly reduced the DNA damage produced in lung fibroblasts depleted of normal GSH protection by the glutamylcysteinyl synthetase inhibitor, L-buthionine-[S,R]-sulfoximine. Although the specific mechanism of NAC protection has not yet been elucidated, these results support the hypothesis that NAC may protect the cells directly, by scavenging ROS induced by UVA and visible radiation, and indirectly by donating cysteine for GSH synthesis.

Acetylcysteine↗
PubMed2002

Hair-element analysis--still on the fringe.

Increasing biological interest in minerals has led to the search for reliable methods to quantify body levels of trace elements and toxic metals. Hair has been a prime candidate because of its ease of collection and the possibility that this body tissue might accurately reflect body loads of these substances. A vast amount of research effort has been expended to explore the value of hair-element analysis. Unfortunately, there are so many confounding factors that influence these measurements that isolated individual results cannot be relied upon. Their current value is in epidemiological studies.

Body Burden↗
PubMed2001

A preliminary investigation of the effects of arsenate on irradiation-induced DNA damage in cultured human lung fibroblasts.

Single-cell gel electrophoresis (the comet assay) was used to assess single-strand breaks (SSBs) produced in cultured lung human fibroblasts by xenon lamp irradiation alone, various concentrations of arsenate [As(V)], alone or various combinations of the two. It was found that significantly higher levels of SSBs were observed in the irradiated cells than the nonirradiated cells and that elevating levels of arsenate enhanced the level of damage detected in both irradiated and nonirradiated cells in a concentration-dependent manner; that is, incubating cells with arsenate alone produced marked DNA damage without an irradiation insult being necessary. The results of this study indicate that arsenate is acting as a cogenotoxin with irradiation in this cell line. This additive effect may also be cocarcinogenic, and as a result it is possible that less solar irradiation may be required to induce skin cancer in arsenic-exposed populations.

Arsenates↗
PubMed1996

St. Thomas' Hospital cardioplegia: enhanced protection with exogenous creatine phosphate.

BACKGROUND: Experimentally, creatine phosphate (CP) improves postischemic recovery of function and reduces postischemic arrhythmias. METHODS: We studied 50 patients undergoing valve replacement. They were randomized into either a control group, who received St. Thomas' Hospital cardioplegic solution No. 1, or a CP-treated group, receiving the same cardioplegic solution plus CP (10 mmol/L). There were no preoperative clinical differences between groups. Assessment was by electrocardiographic analysis, inotropic drug requirement, quantitative birefringence, myocardial high-energy phosphate content, function, and semiquantitative ultrastructural assessment. RESULTS: Direct-current shocks were reduced in the CP-treated group (0.88 +/- 0.15) compared with the control group (1.40 +/- 0.14; p < 0.02), as was the total number of joules (22.0 +/- 3.5 versus 34.4 +/- 3.7, respectively; p <0.02). The incidence of spontaneous sinus rhythm was higher in the CP-treated group (40% versus 8%; p < 0.05) and the incidence of postoperative arrhythmias, lower (8% versus 32%; p < 0.05). Prolonged inotropic administration (12 hours or longer) occurred in fewer patients in the CP-treated group (4% versus 28%; p < 0.05). Response to inotropic support (in the subset of patients requiring this treatment) was significantly greater in the CP-treated group than in the control group. There were no differences in recovery of function, birefringence changes, myocardial high-energy phosphate content, or ultrastructure between groups. CONCLUSIONS: St. Thomas' Hospital cardioplegic solution No. 1 plus CP enhanced myocardial protection and conferred a direct benefit to the patient by reducing postoperative arrhythmias and need of prolonged inotropic support.

Adult↗
PubMed1977

Lack of fatty acid specificity in the lipolysis of oligo and polyunsaturated triacylglycerols by milk lipoprotein lipase.

Native soybean and rapeseed oils and native and rearranged cod liver and peanut oils were subjected to partial hydrolysis with milk lipoprotein lipase and the fatty acid composition and molecular association in the substrates and lipolysis products were determined. In both native and rearranged oils the lack of significant differences in the fatty acid composition and molecular association between the residual and total triacylglycerols suggested that all triacylglycerols were attacked by the lipoprotein lipase at about the same rate. Any enrichment of a specific fatty acid in the diacyl- or monoacylglycerol products of a native oil generally reflected the preferential association of the fatty acid with the 2-position, and to a lesser extent the sn-3-position of the glycerol molecule and was accompanied by a decreased level of the corresponding free fatty acid product. In general, the products of the rearranged oils closely resembled the original triacylglycerols in the fatty acid composition. It is concluded that lipoprotein lipase does not show any detectable specificity for the unsaturated and polyunsaturated fatty acids with double bonds located at carbons 3 to 19 from the carboxyl end of the fatty acid molecules. These findings are compatible with the possible binding of the substrate to lipoprotein lipase through atoms involved in the acyl ester groups of the triacylglycerol molecules.

Animals↗
PubMed1977

Preferential in vivo accumulation of sn-2,3-diacylglycerols in postheparin plasma of rats.

The stereochemical course of in vivo hydrolysis of triacylglycerols by lipoprotein lipase was investigated by determining the structure of diacylglycerol intermediates in postheparin plasma of rats which had been fed [3H]glycerol-labeled Intralipid 2 h before an injection of heparin or had been given an injection of a mixture of [3H]glycerol-Intralipid and heparin. During the clearance of both the natural chylomicrons and the artificial emulsion, sn-2,3-diacylglycerols (60-80%) were found to be the dominant enantiomers. Similar results were obtained when the contribution of the hepatic lipase was altered, either by tying off the mesentery artery and portal vein before injection of heparin, or by injection of heparin directly into the portal vein. These findings are consistent with a preferential release of the acyl group from the sn-1 position of the triacylglycerol molecule as demonstrated previously in vitro. A preferential orientation of the substrate in the enzyme-substrate complex or at the oil-water interface is discussed as a possible basis for these effects.

Animals↗
PubMed1976

Clinical evaluation of clobetasone butyrate in the treatment of children with atopic eczema, and its effect on plasma corticosteroid levels.

Studies were carried out to assess the effectiveness of clobetasone butyrate in treating eczema and psoriasis, and to determine if the compound had any effect on plasma cortisol levels. In the first trial, 71 children with bilateral symmetrical atopic eczema lesions were treated twice daily for 1 week, on one side with 0.05% clobetasone butyrate cream or ointment and on the other with 0.0125% flurandrenolone cream or ointment. Lesions improved or healed in the majority of the patients. Treatment preference showed a trend in favour of clobetasone butyrate but the difference was not statistically significant. In a second open trial, 29 adults with eczema or psoriasis were treated twice daily with clobetasone butyrate for 1 week: lesions in 10 patients remained static, 12 improved, and 7 were cleared. Plasma corticosteroid levels remained within the normal range at the end of the treatment period.

Adolescent↗
PubMedDate not supplied

A double-blind comparison of 0.25% and 0.05% desoxymethasone, 0.1% betamethasone valerate and 1% hydrocortisone creams in the treatment of eczema.

The efficacy and acceptability of 0.25% and 0.05% desoxymethasone, 0.1% betamethasone valerate and 1% hydrocortisone creams were compared in patients with eczema. A double-blind parallel group multi-centre design was employed in which 96 patients were recruited by four centres. Patients used one cream for a 3-week period and follow-up assessment visits were made at weekly intervals. Efficacy variables were: erythema/redness, scaling, itching and extent of area affected. These variables were assessed by both the investigator and the patient. The 0.25% desoxymethasone was the most effective treatment, producing the greatest degree of improvement in all clinical parameters, hydrocortisone was the least effective and 0.05% desoxymethasone was of intermediate effectiveness. The 0.1% betamethasone produced similar results to 0.25% desoxymethasone for half the assessments; for the other half the results were similar to 0.05% desoxymethasone. No adverse effects were reported during the study. The results are discussed in terms of physical properties of the vehicles and corticosteroid potency.

Administration, Topical↗