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D Coates

Publications and source records attributed to D Coates.

At least 37 records · Page 2Linked to original sources
PubMed1998

A novel peptide-processing activity of insect peptidyl-dipeptidase A (angiotensin I-converting enzyme): the hydrolysis of lysyl-arginine and arginyl-arginine from the C-terminus of an insect prohormone peptide.

Insect peptidyl-dipeptidase A [angiotensin I-converting enzyme (ACE)] is a soluble single-domain peptidyl-dipeptidase that has many properties in common with the C-domain of mammalian somatic ACE and with the single-domain mammalian germinal ACE. Mammalian somatic ACE is important in blood homoeostasis, but the role of ACE in insects is not known. Immunocytochemistry has been used to localize ACE in the neuroendocrine system of the locust, Locusta migratoria. Staining was observed in five groups of neurosecretory cells in the brain and suboesophageal ganglion, in the nervi corpori cardiaci, the storage part of the corpora cardiaca and in the nervi corpori allati. In three groups of neurosecretory cells, ACE co-localized with locustamyotropins, suggesting a possible role for the enzyme in the metabolism of these neuropeptides. We demonstrate in vitro a novel activity of ACE that removes pairs of basic amino acid residues from a locustamyotropin peptide extended at the C-terminus with either Gly-Lys-Arg or Gly-Arg-Arg, corresponding to a consensus recognition sequence for endoproteolysis of prohormone proteins by prohormone convertases. The low Km and high kcat values (Km 7.3 and 5.0 microM, kcat 226 and 207 s-1 for the hydrolysis of Phe-Ser-Pro-Arg-Leu-Gly-Lys-Arg and Phe-Ser-Pro-Arg-Leu-Gly-Arg-Arg, respectively) obtained for the hydrolysis of these two peptides by insect ACE means that these peptides, along with mammalian bradykinin, are the most favoured in vitro ACE substrates so far identified. The discovery of this in vitro prohormone-processing activity of insect ACE provides a possible explanation for the intracellular co-localization of the enzyme with locustamyotropin peptides, and provides evidence for a new role for ACE in the biosynthesis of peptide hormones and transmitters.

Animals↗
PubMed1998

'Diprifusor' for general and day-case surgery.

Total intravenous anaesthesia may be most beneficial for day-case surgery with regard to quality of recovery, lack of complications and the ability to sustain an efficient throughput of patients. However, the technique can be applied to all forms of surgery and, with a little practice, consistent results will be achieved. Computerised infusion pumps can be programmed to provide a target blood concentration that can be easily varied to alter the anaesthetic state. The commercially available 'Diprifusor', a target controlled infusion system for propofol, can facilitate the more widespread use of total intravenous techniques and allow their potential benefits to be applied and appreciated more widely. This review outlines some practical considerations that should enable a more confident approach to total intravenous techniques by anaesthetists who are unfamiliar with them.

Adult↗
PubMed1997

Cleavage of arginyl-arginine and lysyl-arginine from the C-terminus of pro-hormone peptides by human germinal angiotensin I-converting enzyme (ACE) and the C-domain of human somatic ACE.

Mammalian germinal angiotensin I-converting enzyme (gACE) is a single-domain dipeptidyl carboxypeptidase found exclusively in male germ cells, which has almost identical sequence and enzymic properties with the C-domain of the two-domain somatic ACE. Mutant mice that do not express gACE are infertile, suggesting a role for the enzyme in the processing of undefined peptides involved in fertilization. A number of spermatid peptides [e.g. cholecystokinin (CCK) and gastrin] are processed from pro-hormones by endo- and exo-proteolytic cleavages which might generate substrates for gACE. We have shown that peptide hormone intermediates with Lys/Arg-Arg at the C-terminus are high-affinity substrates for human gACE. gACE from human sperm cleaved Arg-Arg from the C-terminus of the CCK5-GRR (GWMDFGRR), a peptide corresponding to the C-terminus of a CCK-gastrin prohormone intermediate. Hydrolysis of CCK5-GRR by recombinant human C-domain ACE was Cl- dependent, with maximal activity achieved in 5-10 mM NaCl at pH 6.4. C-Domain ACE cleaved Lys/Arg-Arg from the C-terminus of dynorphin-(1-7), a pro-TRH peptide KRQHPGKR, and two insect peptides FSPRLGKR and FSPRLGRR. C-Domain ACE displayed high affinity towards all these substrates with Vmax/Km values between 14 and 113 times greater than the Vmax/Km for the conversion of the best known ACE substrate, angiotensin I, into angiotensin II. In conclusion, we have identified a new class of substrates for human gACE, and we suggest that gACE might be an alternative to carboxypeptidase E for the trimming of basic dipeptides from the C-terminus of intermediates generated from pro-hormones by subtilisin-like convertases in human male germ cells.

Chlorides↗
PubMed1996

The Acer gene of Drosophila codes for an angiotensin-converting enzyme homologue.

Mammalian angiotensin-converting enzyme (ACE) exists as two forms, somatic (sACE), controlling blood pressure via angiotensin II, and testicular (tACE), whose function is unknown. The former has two highly homologous N- and C-terminal Zn2+ metallopeptidase active sites, whereas the latter only has one, which is identical to the C-terminal domain of sACE. We have sequenced 2452 bases of a 3.1-kb mRNA whose predicted translation product shows 40% identity with mammalian testicular ACE, and 48% identity with an already identified Drosophila homologue of ACE (Ance). We have termed this gene Acer (Angiotensin converting enzyme-related). Acer mRNA is found in the developing dorsal vessel (heart) during embryogenesis. Phylogenetic analysis indicates that duplication of an ancestral ACE gene occurred in the lineage leading to the arthropods, independently of the duplication which gave rise to the two domain somatic ACE of mammals.

Amino Acid Sequence↗
PubMed1996

Purification and characterization of prostaglandin-H E-isomerase, a sigma-class glutathione S-transferase, from Ascaridia galli.

Comparison of partial primary sequences of sigma-class glutathione S-transferases (GSH) of parasitic helminths and a GSH-dependent prostaglandin (PG)-H D-isomerase of rat immune accessory cells suggested that some of the helminth enzymes may also be involved in PG biosynthesis [Meyer and Thomas (1995) Biochem. J. 311, 739-742]. A soluble GSH transferase of the parasitic nematode Ascaridia galli has now been purified which shows high activity and specificity in the GSH-dependent isomerization of PGH to PGE, comparable to that of the rat spleen enzyme in its isomerization of PGH to PGD, and similarly stimulates the activity of prostaglandin H synthase. The enzyme subunit is structurally related to the rat spleen enzyme and sigma-class GSH transferases of helminths according to the partial primary sequence. The data support the hypothesis that some sigma-class GSH transferases of helminth parasites are involved in PG biosynthesis which, in the case of PGE, is likely to be associated with the subversion or suppression of host immunity. A PG-H E-isomerase of comparable specificity and activity has not previously been isolated.

Amino Acid Sequence↗
PubMed1996

Improved detection of barley yellow dwarf virus in single aphids using RT-PCR.

The detection of a British isolate of barley yellow dwarf virus (BYDV-G, PAV-like) from individual vector aphids, using a combined assay of reverse transcription and polymerase chain reaction (RT-PCR) is reported. The method makes use of a multiplex format, including internal control primers directed at conserved regions of insect actin. The actin primers serve as controls for each stage of the method and are suitable for use in a range of invertebrate species. Detection of BYDV in vector aphids for use in forecasting systems is at present carried out using an enzyme-amplified ELISA system. In direct comparisons with the amplified ELISA, RT-PCR shows an increase in sensitivity detecting 11 fg of purified virus. Detection of virus in ELISA-negative aphids by RT-PCR was also demonstrated, and its potential as a routine diagnostic tool for virus detection in aphids is discussed.

Animals↗
PubMed1996

Sporicidal activity of sodium dichloroisocyanurate, peroxygen and glutaraldehyde disinfectants against Bacillus subtilis.

The activity of sodium dichloroisocyanurate (NaDCC), peroxygen and glutaraldehyde disinfectants against spores of Bacillus subtilis NCTC 10073 was evaluated using suspension tests. The activity of aqueous solutions of NaDCC disinfectants increased with the level of available chlorine (av.Cl) but was considerably reduced by low levels of blood. Five percent Titan Sanitizer (1200 ppm av.Cl) achieved a > 10(5)-fold reduction in spore count (kill) in 3 h in the absence of blood but no kill in 3 h with 2% blood present. One percent Presept (3180 ppm av.Cl) achieved a > 10(5)-fold kill in 1 h in the absence of blood and in 2 h with 2% blood present. One percent Haz-Tab (5750 ppm av.Cl) achieved > 10(5)-fold kill in 5 min in the absence of blood and in 30 min with 2% blood present. One percent Virkon (peroxygen) achieved a 10(5)-fold kill in 2-3 h in the absence of blood but little kill in 3 h with 2% blood present. Nu-Cidex (peracetic acid) was rapid in action and tolerant of organic matter. A 24 h old solution achieved a > 10(5)-fold kill in 5 min with 10% serum present. Cidex Long-Life (glutaraldehyde) worked much slower; a 28-day-old solution achieved a > 10(5)-fold kill in 2 h with 4% blood present. Neat sporicidin (glutaraldehyde-phenate) was slightly superior to Cidex Long-Life but in a 1 in 8 dilution exhibited markedly reduced activity; 30-day-old solution achieved a 10(4)-fold kill in 10 h in the absence of blood but only a 10(2)-fold kill in 10 h with 2% blood present.

Bacillus subtilis↗
PubMed1996

Metabolism and inactivation of neurotransmitters in nematodes.

The nematode nervous system employs many of the same neurotransmitters as are found in higher animals. The inactivation of neurotransmitters is absolutely essential for the correct functioning of the nervous system. In this article we discuss the various mechanisms used generally in animal nervous systems for synaptic inactivation of neurotransmitters and review the evidence for similar mechanisms operating in parasitic and free-living nematodes. The sequencing of the entire Caenorhabditis elegans genome means that the sequence of nematode genes can be accessed from the C. elegans database (ACeDB) and this wealth of information together with the increasing knowledge of the genetics of this free-living nematode will have great impact on all aspects of nematode neurobiology. The review will provide an insight into how this information may be exploited to identify and characterize target proteins for the development of novel anti-nematode drugs.

Amino Acid Sequence↗
PubMed1996

Infection control and urine drainage bag design.

Catheterisation carries a significant risk of infection. Catheter and drainage system design should reduce this risk. No one system will suit all users; new designs need extensive trials in use.

Cross Infection↗
PubMed1995

Cloning and expression of an evolutionary conserved single-domain angiotensin converting enzyme from Drosophila melanogaster.

Mammalian somatic angiotensin converting enzyme (EC 3.4.15.1, ACE) consists of two highly homologous (N- and C-) domains encoded by a duplicated gene. We have identified an apparent single-domain (67 kDa) insect angiotensin converting enzyme (AnCE) in embryos of Drosophila melanogaster which converts angiotensin I to angiotensin II (Km, 365 microM), removes Phe-Arg from the C terminus of bradykinin (Km, 22 microM), and is inhibited by ACE inhibitors, captopril (IC50 = 1.1 x 10(-9) M) and trandolaprilat (IC50 = 1.6 x 10(-8) M). We also report the cloning and expression of a Drosophila AnCE cDNA which codes for a single-domain 615-amino acid protein with a predicted 17-amino acid signal peptide and regions with high levels of homology to both the N- and C-domains of mammalian somatic ACE, especially around the active site consensus sequence. Northern analysis identified a single 2.1-kilobase mRNA in Drosophila embryos, and Southern analysis of Drosophila genomic DNA indicates that the insect gene is not duplicated. When expressed in COS-7 cells, the AnCE protein is a secreted enzyme, which converts angiotensin I to angiotensin II and is inhibited by captopril (IC50 = 5.6 x 10(-9) M) and trandolaprilat (IC50 = 2 x 10(-8) M). The evolutionary significance of these results is discussed.

Amino Acid Sequence↗
PubMed1995

The process of learning in dementia-carer support programmes: some preliminary observations.

Theories of experiential learning, notably the theory of andragogy, can be used to elucidate the process of learning in dementia-carer support programmes. Such theories attach importance to the positive influence of life experience and maturity, and to the salience of personal issues, but their appropriateness needs to be critically analysed. Stress is a common manifestation among dementia carers and its presence can significantly affect openness to learning. As a result of recent policy changes and of demographic shifts, nurses are likely to be increasingly involved in carer support programmes. They need to be aware of the complex issues addressed in this paper.

Adaptation, Psychological↗
PubMed1994

How to produce a hospital disinfection policy.

The steps required to produce and implement a hospital disinfection policy are discussed including: the formation of the team responsible for the policy; the investigation and compilation of current methods of decontamination; assessment of these methods and selection of the best options by reference to model disinfection policies; planning and producing the policy; choosing the best format; implementation of the policy and staff training; and auditing and updating the policy. Guidance is given on the selection of suitable procedures for decontamination of the environment, the skin and mucous membranes, and endoscopes and other items.

Disinfection↗
PubMed1994

A comparison of the bactericidal activity of 'Phoraid 6000' and 'Clearsol' disinfectants.

The bactericidal activity of 'Phoraid 6000' and 'Clearsol' disinfectants was evaluated using suspension and surface tests. In suspension tests, 2% 'Phoraid' achieved a > 5 log10 reduction of Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus in 1 min in the absence of blood, but negligible activity in 10 min in the presence of 1% blood; 10% 'Phoraid' exhibited no useful activity in the presence of 5% blood and 20% Phoraid no useful activity in the presence of 10% blood. In contrast, 'Clearsol' was very resistant to neutralization by blood: 1% 'Clearsol' achieved a > 5 log10 reduction of P. aeruginosa, E. coli and S. aureus in 5 min in the presence of > or = 70% blood. In surface tests, undiluted 'Phoraid 6000' failed to disinfect wet blood contaminated with either P. aeruginosa, E. coli or Proteus vulgaris in the 2-min exposure period. 'Clearsol' gave mixed results: 2% 'Clearsol' was very effective but the standard use-dilution of 1% proved inadequate.

Bacteria↗