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V Murray

Publications and source records attributed to V Murray.

At least 19 recordsLinked to original sources
PubMed1999

Protein-DNA footprinting of the human epsilon-globin promoter in human intact cells using nitrogen mustard analogues and other DNA-damaging agents.

Nitrogen mustard analogues, bleomycin and dimethyl sulphate (DMS) have been used as probes of protein-DNA interactions in intact human cells. The sites of damage have been determined at base pair resolution in the single copy epsilon-globin gene promoter in erythroid K562 cells, non-erythroid HeLa cells and purified DNA. Exponential amplification of gene-specific damage fragments was achieved using the ligation-mediated polymerase chain reaction (LMPCR) technique and analysed on DNA sequencing gels. A comparison of the relative damage band intensities between purified DNA and intact cells revealed several significant differences - both protection (footprint) and enhancement. These differences occurred at putative transcription factor binding sites and hence are thought to be due to protein-DNA interactions. A major feature of the band intensity ratio plots was the footprint observed at the CCAAT box binding motif as revealed by nitrogen mustard analogues. Enhanced band intensity (hypersensitivity) was displayed at the 5'- and 3'-ends of the CCAAT box in K562 cells - this feature was absent in HeLa cells and in vitro reconstitutions. A footprint was found at the GATA-1 motif in K562 cells that was also absent in non-expressing HeLa cells. Footprints were also evident at the TATA box, CACC box and the epsilonF1 DNA binding motif in K562 cells.

Bleomycin↗
PubMed1999

A survey of the sequence-specific interaction of damaging agents with DNA: emphasis on antitumor agents.

This article reviews the literature concerning the sequence specificity of DNA-damaging agents. DNA-damaging agents are widely used in cancer chemotherapy. It is important to understand fully the determinants of DNA sequence specificity so that more effective DNA-damaging agents can be developed as antitumor drugs. There are five main methods of DNA sequence specificity analysis: cleavage of end-labeled fragments, linear amplification with Taq DNA polymerase, ligation-mediated polymerase chain reaction (PCR), single-strand ligation PCR, and footprinting. The DNA sequence specificity in purified DNA and in intact mammalian cells is reviewed for several classes of DNA-damaging agent. These include agents that form covalent adducts with DNA, free radical generators, topoisomerase inhibitors, intercalators and minor groove binders, enzymes, and electromagnetic radiation. The main sites of adduct formation are at the N-7 of guanine in the major groove of DNA and the N-3 of adenine in the minor groove, whereas free radical generators abstract hydrogen from the deoxyribose sugar and topoisomerase inhibitors cause enzyme-DNA cross-links to form. Several issues involved in the determination of the DNA sequence specificity are discussed. The future directions of the field, with respect to cancer chemotherapy, are also examined.

Antineoplastic Agents↗
PubMed1999

Plasma semicarbazide-sensitive amine oxidase in stroke.

Semicarbazide-sensitive amine oxidase (SSAO) has been suggested to be involved in the development of vascular endothelial damage. The source of the soluble form of SSAO found in the blood serum is unknown. However, it has been speculated that it is secreted from cells within the vascular wall where high activity of the enzyme is found. Altered SSAO activity has been reported in atherosclerotic plaques of the human aorta. Stroke is a manifestation of long-term atherosclerotic disease, and in this study, plasma SSAO activities were estimated in 42 patients with cerebral thrombosis and 26 patients with cerebral embolism, and compared to two control groups of 45 individuals in total. No statistically significant differences were found between the patient groups and controls regarding plasma SSAO activity, suggesting that changes in the soluble form of SSAO found in the circulation do not play a major role in this type of acute cerebrovascular event. Furthermore, it does not seem likely that the involvement of vascular tissue occurring in stroke results in release of the enzyme into the circulation. Nevertheless, further studies on tissue-bound SSAO in cerebral vessels would be of great interest.

Aged↗
PubMed1999

Outbreak of gastroenteritis associated with contamination of a private borehole water supply.

An outbreak of gastroenteritis affected 58 of 700 people served by a private water supply at a biological research institute located in a village. No cases were detected in 250 residents of the same village served by a public water supply over the same period. Consumer complaints of tainting and laboratory evidence of bacterial and chemical contamination were obtained for the private water supply, but not for the public water supply. The outbreak was probably caused by contamination from a nearby sewer of a borehole used for the private supply. The outbreak showed how a large, private water supply posed a substantial risk to public health. The regulatory framework for such water supplies should be modified to ensure their safer design and operation.

Adolescent↗
PubMed1998

The interaction of DNA-targeted platinum phenanthridinium complexes with DNA.

Cisplatin analogues were synthesised that consisted of platinum(II) diamine complexes tethered via a polymethylene chain ( n = 3, 5, 8 and 10) to a phenanthridinium cation. Both chloro and iodo leaving groups were examined. DNA adduct formation was quantitatively analysed using a linear amplification system with the plasmid pGEM-3Zf(+). This system utilised Taq DNA polymerase to extend from an oligonucleotide primer to the damage site. This damage site inhibited the extension of the DNA polymerase. The products were electrophoresed on a DNA sequencing gel enabling adduct formation to be determined at base pair resolution. The damage intensity at each site was determined by densitometry. The platinum phenanthridinium complexes were shown to damage DNA at shorter incubation times than cisplatin. To produce similar levels of damage, an 18 h incubation was required for cisplatin compared to 30 min for the n = 3 platinum phenanthridinium complexes; this indicates that the intercalating chromophore causes a large increase in the rate of platination. A reaction mechanism involving direct displacement of the chloride by the N-7 of guanine may account for the rate increase. These results indicate that further development of these compounds could lead to more effective cancer chemotherapeutic agents.

Antineoplastic Agents↗
PubMed1998

DNA sequence selectivity of cisplatin analogues in intact human cells.

The sequence specificity of ten cisplatin analogues was examined in intact human cells. Six of these compounds have anti-tumour activity. The sequence selectivity was investigated using a Taq DNA polymerase/linear amplification assay on damaged DNA extracted from treated cells. Cisplatin and tetraplatin(IV) produced strong damage and DACH RR(II) and cis-[Pt(II)Cl,2(iPrNH2)2] weak DNA damage in intact HeLa cells. The sequence selectivity of tetraplatin(IV) in intact human cells was very similar to that of cisplatin and favored runs of consecutive purines, especially consecutive guanines. The compounds transplatin, carboplatin, cis-[PtCl(NH3)2(C8H17.NH2)], cis-[PtCl2(iPentNH2)2], cis-[PtCl2(C6H11NH2)2, DACH SS(II) and CHIP(IV) did not significantly damage DNA in cells. It was concluded that the interactions of these cisplatin analogues with DNA in human cells were strongly influenced by their ability to damage purified DNA.

Antineoplastic Agents↗
PubMed1998

The effect of a lindane and mercury polluting incident on the health of a community: the Somerton Health Survey.

OBJECTIVES: This study sought to identify possible illnesses of people exposed to lindane and methyl mercury following a pollution incidence in Somerton, Somerset, UK. METHODS: A self-administered questionnaire survey was posted to 1500 residents in three selected areas of Somerton to identify symptoms of possible illness over a 3 month period. RESULTS: There was a 74% response rate. People living near the stream had higher levels of reported mental symptoms and itching skin than in controls. Poisoning as the cause of the mental symptoms was excluded as the individuals had normal blood levels of lindane or mercury. Other symptoms were no higher in one area than another or from one time period to another. CONCLUSIONS: The survey, using controls in time and space, was able to explore, the pollution incident's contribution to the toxicity of residents and how this related to mental symptoms experienced by the residents.

Air Pollutants↗
PubMed1998

The DNA sequence specificity of hedamycin damage determined by ligation-mediated PCR and linear amplification.

The DNA sequence specificity of hedamycin damage was compared using two techniques: Ligation-mediated PCR (LMPCR) and Linear Amplification (LA). The electrophoretic mobility of LA products were made comparable with LMPCR products by using a primer with a 27 bp non-binding 5'-extension. By direct comparison of the damage intensity (as represented by each of the methods), considerable bias was found in the LMPCR system with respect to LA--resulting in the under representation of lesions with T as the base 3' to the damage site. In view of this observation some caution should be exercised in the interpretation of data for DNA damage/repair specificity derived by LMPCR. In addition the extended primer LA method used in these experiments, could be applied to generate a dideoxy sequencing ladder for analysis of LMPCR products. This would negate the need to prepare Maxam-Gilbert chemical sequencing fragments for amplification through LMPCR.

Alkylating Agents↗
PubMed1998

Detection of protein-DNA interactions at beta-globin gene cluster in intact human cells utilizing hedamycin as DNA-damaging agent.

The DNA sequence specificity of hedamycin (HDM) damage was investigated in the single-copy human beta-globin gene cluster in an erythroid cell line, a nonerythroid cell line, and purified genomic DNA. The target DNA sequences for this study were the beta-globin gene locus control region (LCR) hypersensitive site 2 (HS-2) and the beta-globin gene promoter. The DNA fragments produced by HDM damage in these target sequences were selectively amplified by the ligation-mediated polymerase chain reaction (LMPCR) and analyzed at nucleotide resolution by DNA-sequencing gel electrophoresis. The DNA sequences damaged by HDM in the cellular environment were found to be similar to that observed in the purified genomic DNA. However, substantial differences did occur between the intensity of cellular and purified genomic DNA reaction products at discrete regions corresponding to transcription factor-binding motifs. This was most apparent in the LCR HS-2 at the tandem NF-E2/AP-1 motif, where the DNA damage activity of HDM was severely impaired. This motif has been shown to bind to the erythroid-specific nuclear factor-erythroid 2 (NF-E2) and the widely distributed activator protein-1 (AP-1). The HDM damage protection patterns or "genomic footprints" observed at this motif were probably caused by protein-DNA interactions with one or both of these transcription factors. This result indicates that the DNA damaging activity of HDM in cells is sensitive to bound nuclear factors. Because HDM can enter intact cells, where its DNA damaging activity is modulated by protein-DNA interactions, it may have application in genomic footprinting experiments.

Alkylating Agents↗
PubMed1997

Interaction of 11 cisplatin analogues with DNA: characteristic pattern of damage with monofunctional analogues.

In this paper the sequence specificity of DNA damage has been determined for 11 cisplatin analogues. A number of the analogues used in this study have been included in clinical trials. A Taq DNA polymerase linear amplification technique was utilised to ascertain the sequence selectivity of cisplatin analogues damage to DNA. The analogues differed in their ability to damage DNA with cisplatin being the most effective DNA damaging agent followed by (in decreasing order): tetraplatin (tetrachloro(1,2-diaminocyclohexane)platinum(IV) (RR isomer)), cis-dichlorobis(isopropylamine)platinum(II), dichloro(1,2-diaminocyclohexane)platinum(II) (SS isomer), dichloro(1,2-diaminocyclohexane)platinum(II) (RR isomer), cis-bis(cyclohexylamine)dichloroplatinum(II), carboplatin, cis-dichlorobis(isopentylamine)platinum(II), and CHIP (cis-dichloro-trans-dihydroxybis(isopropylamine)platinum(IV)). However, the sequence specificity of these analogues was similar in position and relative intensity of damage. We also provide evidence that platinum(IV) complexes can damage DNA without being reduced to platinum(II). It was found that a 10-fold higher concentration of cisplatin was required to damage DNA in Tris-HCl compared to Hepes buffers. In this paper we have detected a characteristic pattern of damage with monofunctional analogues that could be used to determine the mode of binding of a cisplatin analogue with DNA. The monofunctional analogues tested were chloro(diethylenetriamine)platinum(II) and cis-diamminechloro(1-octylamine)platinum(II) as well as transplatin.

Antineoplastic Agents↗
PubMed1997

Protein-DNA interactions in the human beta-globin locus control region hypersensitive site-2 as revealed by four nitrogen mustards.

Four nitrogen mustards have been used in this study to examine protein-DNA interactions in intact human cells, specifically at the locus control region hypersensitive site-2 (LCR HS-2) of the human beta-globin locus. Three of these nitrogen mustards are DNA-targeted by attachment of an acridine or amsacrine intercalating chromophore, while the fourth (chlorambucil) is a non-targeted mustard. The ligation-mediated PCR technique was used to determine the sites of damage at base pair resolution on DNA sequencing gels. A densitometric comparison was made between DNA damaged in intact erythroid K562 cells and in purified DNA. The intensity of DNA damage sites in the LCR HS-2 were found to differ significantly between intact K562 cells and purified DNA. At the NF-E2/AP-1 motif, pronounced damage protection was observed in DNA derived from drug treated cells. The nuclear factor- erythroid 2 (NF-E2) protein factor is thought to bind at this NF-E2/AP-1 motif in K562 cells. Other sites of protection and enhancement that corresponded to known transcription factor binding sites were also detected. These nitrogen mustards are therefore very effective compounds for detection of transcription factor binding to DNA in intact cells and are superior to other commonly used agents. The sequence selectivity of the compounds was determined using plasmid DNA and compared to that found in intact cells. The acridine-based nitrogen mustard had a preference for forming adducts at guanine bases, while the two amsacrine-based nitrogen mustards and chlorambucil formed adducts at both guanine and adenine bases.

Aminacrine↗
PubMed1997

Use of an automated sequencer to determine the sequence specificity of DNA damage.

An automated sequencer was used to determine the sequence specificity of DNA damage caused by hedamycin in the plasmid pUC19 using a linear amplification/Taq DNA polymerase method. Previously, manual DNA sequencers have been in widespread use to investigate the sequence specificity of a DNA damaging agent. Manual DNA sequencers are restricted in the length of DNA sequence that can be read at base pair resolution for densitometry. An automated sequencer can greatly expand on the length of analysable DNA sequence. An additional important capability of the automated sequencer, is the ability to quantitate the intensity of damage at each base pair site. Thus we have used the automated sequencer to elucidate the sequence specificity of DNA damage for 300 bp. We have carried out an extended analysis of the sequence specificity of hedamycin DNA damage and found that the sequence 5'-cGt-3', tGt and cGg are preferentially damaged. The sequence specificity of cisplatin was also investigated.

Alkylating Agents↗
PubMed1997

Use of paracetamol for suicide and non-fatal poisoning in the UK and France: are restrictions on availability justified?

OBJECTIVE: To investigate the relationship between the availability of paracetamol and its use for overdose and suicide. DESIGN: Analysis of routinely collected information on time trends for paracetamol suicides, non-fatal overdoses, and sales. SETTING: England and Wales and France. RESULTS: There were strong correlations between trends in paracetamol sales in the UK and trends in non-fatal paracetamol overdose in Oxford between 1976 and 1993 (Spearman's r = 0.86; 95% confidence interval (CI) 0.54, 0.96) and between paracetamol sales and non-fatal overdoses in France between 1974 and 1990 (r = 0.99; 95% CI 0.97, 1.00). Sales figures were also correlated with paracetamol related suicides in both England and Wales, 1983-91 (r = 0.72; 95% CI 0.11, 0.94) and France, 1974-90 (r = 0.79; 95% CI 0.50, 0.92). Similarly strong relationships were observed between trends in non-fatal overdoses and suicide by paracetamol poisoning in England and Wales (r = 0.85; 95% CI 0.61, 0.95) and France (r = 0.79; 95% CI 0.50, 0.92). It is estimated that approximately 32,000 overdoses involving paracetamol occur annually in England and Wales. Fatality rates from paracetamol overdose were four times as high in England and Wales (0.4%, 95% CI 0.38, 0.46) as in France (0.1%, 95% CI 0.06, 0.17). CONCLUSION: Trends towards greater availability of paracetamol are paralleled by increases in its use for both non-fatal overdose and suicide. Paracetamol related morbidity and mortality seem to be less frequent in France where the quantity of paracetamol in a single purchase is limited. Although not conclusive, these data add to a body of evidence which suggests that restrictions in the quantity of paracetamol available as a single purchase in the UK may reduce suicide and liver failure related to paracetamol.

Acetaminophen↗