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Biomedical subjects

D Phillips

Publications and source records attributed to D Phillips.

At least 19 recordsLinked to original sources
PubMed2007

Relationships between the density of different indicator organisms on sheep and beef carcasses and in frozen beef and sheep meat.

AIM: To describe the relationship between the concentration of different indicator bacteria in red meat. METHODS AND RESULTS: Enumeration data for aerobic plate count (APC), Enterobacteriaceae, coliforms and Escherichia coli biotype I were analysed from an Australia-wide survey of beef carcasses, sheep carcasses, frozen beef and frozen sheep meat. In all commodities, there was only low-to-moderate rank correlation (0.16-0.47) between concentration of APC and concentration of each Gram-negative indicator. Rank correlations between counts of Gram-negative indicators were much higher (0.47-0.92) especially when nondetections were excluded from analysis (0.78-0.94). Receiver-operator characteristics analysis showed that detection of coliforms can predict the presence of E. coli biotype I with almost 100% sensitivity but fails to predict absence in 2.7-8.5% of samples not containing E. coli biotype I. CONCLUSIONS: Enumeration of coliforms is a useful adjunct to enumeration of E. coli biotype I or Enterobacteriaceae in red meat. The density of coliforms or Enterobacteriaceae can be used to predict the presence or absence of E. coli biotype I, although when the latter is at low prevalence errors in positive test prediction can be large. SIGNIFICANCE AND IMPACT OF THE STUDY: A quantitative basis is provided for comparing the concentration of different indicator bacteria measured in the production, regulation and trade of red meat.

Animals↗
PubMed2006

Molecular assembly of meiotic proteins Asy1 and Zyp1 and pairing promiscuity in rye (Secale cereale L.) and its synaptic mutant sy10.

Assembly of two orthologous proteins associated with meiotic chromosome axes in Arabidopsis thaliana (Asy1 and Zyp1) was studied immunologically at meiotic prophase of meiosis of wild-type rye (Secale cereale) and its synaptic mutant sy10, using antibodies derived from A. thaliana. The temporal and spatial expression of the two proteins were similar in wild-type rye, but with one notable difference. Unlike A. thaliana, in which foci of the transverse filament protein Zyp1 appear to linearize commensurately with synapsis, linear tracts of Asy1 and Zyp1 protein form independently at leptotene and early zygotene of rye and coalign into triple structures resembling synaptonemal complexes (SCs) only at later stages of synapsis. The sy10 mutant used in this study also forms spatially separate linear tracts of Asy1 and Zyp1 proteins at leptotene and early zygotene, and these coalign but do not form regular triple structures at midprophase. Electron microscopy of spread axial elements reveals extensive asynapsis with some exchanges of pairing partners. Indiscriminate SCs support nonhomologous chiasma formation at metaphase I, as revealed by multi-color fluorescence in situ hybridization enabling reliable identification of all the chromosomes of the complement. Scrutiny of chiasmate associations of chromosomes at this stage revealed some specificity in the associations of homologous and nonhomologous chromosomes. Inferences about the nature of synapsis in this mutant were drawn from such observations.

Chromosome Pairing↗
PubMed2005

Imaging fluorescence lifetime heterogeneity applied to GFP-tagged MHC protein at an immunological synapse.

Fluorescence imaging of green fluorescent protein (GFP) may be used to locate proteins in live cells and fluorescence lifetime imaging (FLIM) may be employed to probe the local microenvironment of proteins. Here we apply FLIM to GFP-tagged proteins at the cell surface and at an inhibitory natural killer (NK) cell immunological synapse (IS). We present a novel quantitative analysis of fluorescence lifetime images that we believe is useful to determine whether apparent FLIM heterogeneity is statistically significant. We observe that, although the variation of observed fluorescence lifetime of GFP-tagged proteins at the cell surface is close to the expected statistical range, the lifetime of GFP-tagged proteins in cells is shorter than recombinant GFP in solution. Furthermore the lifetime of GFP-tagged major histocompatibility complex class I protein is shortened at the inhibitory NK cell IS compared with the unconjugated membrane. Following our previous work demonstrating the ability of FLIM to report the local refractive index of GFP in solution, we speculate that these lifetime variations may indicate local refractive index changes. This application of our method for detecting small but significant differences in fluorescence lifetimes shows how FLIM could be broadly useful in imaging discrete membrane environments for a given protein.

Cell Line, Transformed↗
PubMed2004

A cautionary case: the SynerGraft vascular prosthesis.

To date no prosthetic vascular prosthesis performs as well as autologous conduits for small diameter arterial reconstruction. We report the outcome of our first case using a new vascular prosthesis marketed by Cryolife, the SynerGraft. This Xenograft prostheses is claimed to eliminate the problems of the previous generation of gluteraldehyde treated grafts. Two 50 cm SynnerGrafts were anastomosed end to end and used as a femoral-posterior tibial bypass graft in a 68-year-old man who presented with an acutely ischaemic left leg. Our patient represented at 8 weeks with aneurysmal degeneration along the course of the graft. We urge caution in the use of these grafts until convincing data in humans is presented.

Aged↗
PubMed2003

Degradation of extracellular matrix components by defined proteinases from the greenbottle larva Lucilia sericata used for the clinical debridement of non-healing wounds.

BACKGROUND: Larvae of the greenbottle fly Lucilia sericata are used routinely for the clinical treatment of difficult necrotic and infected wounds. Degradation by proteinases contained in larval excretory/secretory (ES) products is thought to contribute to wound debridement by removal of dead tissue. However, proteinase activity may also affect host tissue remodelling processes. OBJECTIVES: To identify proteolytic enzymes derived from L. sericata ES products with activities against fibrin and extracellular matrix (ECM) components. METHODS: Larval proteinase activities were assayed in vitro using class-specific substrates and inhibitors. Their action against fibrin and ECM components was examined using sodium dodecyl sulphate-polyacrylamide gel electrophoresis. RESULTS: Three classes of proteolytic enzyme were detected in the secretions using fluorescein isothiocyanate-labelled casein as a model substrate. The predominant activity belonged to serine proteinases (pH optima 8-9) of two different subclasses (trypsin-like and chymotrypsin-like), with a weaker aspartyl proteinase (pH 5) and a metalloproteinase (pH 9) with exopeptidase characteristics also present. Using skin-relevant ECM components as substrates L. sericata ES products solubilized fibrin clots and degraded fibronectin, laminin and acid-solubilized collagen types I and III. Hydrolysis of ECM macromolecules was inhibited by preincubating ES products with phenylmethylsulphonyl fluoride but not 4-amidinophenylmethylsulphonyl fluoride, indicating that degradation was due to the 'chymotrypsin-like' serine proteinase. CONCLUSIONS: These data suggest that a combination of L. sericata ES proteinases involving chymotrypsin-like and trypsin-like activities could potentially influence wound healing events when maggots are introduced into necrotic and infected wounds, with the chymotrypsin-like activity involved in the remodelling of ECM components.

Animals↗
PubMed2001

Attempts to measure sensitiser photophysics in opaque tissue.

Diffuse reflectance laser flash photolysis has been used in an attempt to measure transient triplet spectra of the sensitisers, disulphonated aluminium phthalocyanine and porphyrin IX (derived from 5-amino laevulinic acid), in opaque tissue and models. The latter consisted of tissue phantoms; the former included rat liver and red blood cells. In all cases, triplet-triplet absorption spectra with relatively poor signal-to-noise were obtained providing some encouragement in the application of this technique to in vivo studies on photosensitisers.

Aminolevulinic Acid↗
PubMed2001

Differences between blood and liver aromatic DNA adduct formation.

Aromatic DNA adducts in the livers and blood of grey mullet (Mugil sp.) have been monitored between 1993 and 1996 by the isolation of DNA and the postlabeling of the DNA adducts with 32P. The grey mullet were sampled from three well-characterised harbours, two in the northeastern Mediterranean and one in the northeastern Black Sea near Trabzon close to a site of aquaculture. One of the northeastern Mediterranean harbours was highly polluted with polynuclear aromatic hydrocarbons (PAHs) and was rich in inorganic nutrients. Larger grey mullet lived in this harbour than the other harbours and their livers possessed approximately 100 aromatic DNA adducts per 10(8) nucleotides. The livers from grey mullet in the other two harbours possessed < or = 25 aromatic DNA adducts per 10(8) nucleotides but these concentrations depended on a variety of factors. Blood cell being regenerated more rapidly than liver cells, it is found that generally the ratio of DNA adduct concentrations in piscine liver and blood will increase with the pollution of the surrounding marine environment. Fishes are acceptable models for the metabolism of xenobiotics and the associated formation of harmful aromatic DNA adducts in organisms.

Animals↗
PubMed2001

HER-2/neu in breast cancer: interobserver variability and performance of immunohistochemistry with 4 antibodies compared with fluorescent in situ hybridization.

The immunohistochemistry (IHC) performance of 4 anti-HER-2/neu antibodies was compared with fluorescent in situ hybridization (FISH) analysis of HER-2/neu gene expression in breast cancer patients considered for Herceptin (Trastuzumab) therapy. Interobserver variability in IHC interpretation was measured. Formalin-fixed tissue was received from 24 provincial hospital laboratories. The following anti-Her-2 antibodies were used: DAKO A0485 (polyclonal), Novacastra CB11 (monoclonal), Zymed TAB250 (monoclonal), and DAKO HercepTest (polyclonal). Additional sections were analyzed by FISH (Vysis). Three pathologists blinded to FISH results independently interpreted invasive tumor cell membranous staining on a scale of 0 to +3. The HER-2/neu gene was considered amplified when the FISH signal ratio of HER-2/CEP-17 was > or =2.0. Blocks from all hospitals and of all ages were suitable for IHC and FISH analysis. No interlaboratory analysis variability was noted. The interobserver agreement (kappa) for stain intensity for each antibody was good for 0 and +3 but poor for +1 and +2. Reasonable concordance between IHC and FISH was found with three of the four antibodies. TAB250 was the most sensitive antibody. For the three pathologists, the IHC sensitivities and specificities compared with FISH using 0/+1 as negative and +2/+3 as positive were as follows: A0485, 63-84/95-98; CB11, 63-66/97-98; TAB-250, 82-100/94-95; HercepTest, 59-77/91-93. The positive and negative predictive values varied by stain intensity. Stain scores of 0 and +3 were highly predictive of gene status. Stain scores of +1 and +2 were not sufficiently predictive to classify cases as amplified versus nonamplified. IHC is a reasonable first test to assess HER-2/neu status in patients with breast cancer. For most cases, DAKO A0485, TAB250, and HercepTest adequately predicted gene status. In cases with stain intensity of +1 or +2, the interobserver agreement is poor, and the predictive value is unsatisfactory for clinical use. Additional testing, preferably with FISH, is recommended.

Antibodies, Monoclonal↗
PubMed2001

The expected economic impact of selected exotic diseases on the pig industry of Australia.

The authors assess the expected economic impact of three exotic diseases on the pig industry of Australia. An integrated epidemiological/economic approach was used to assess the effects of classical swine fever, Nipah virus and porcine reproductive and respiratory syndrome. Scenarios involving either an epidemic event, in which the outbreaks were confined to selected regions and were eradicated, or an endemic situation, in which the diseases became established in Australia, were studied. Based only on loss of sales and disposal costs, epidemics resulted in regional losses in income of the order of AUS$10 million-AUS$30 million (16%-37%) depending on disease and region. If any of these diseases became established, opportunity losses in gross national pig income of 5%-11% per year would occur, with classical swine fever the most serious of the three diseases. Establishment of any of the diseases would lead to rapid structural change in the pig industry, with concomitant social and economic dislocation in regional Australia.

Animal Husbandry↗
PubMed2001

Microbiological quality of Australian beef.

A survey of the microbiological quality of beef carcasses and boneless beef produced in Australia was conducted during the period June to November 1998. Sponge samples were collected from 1,275 carcasses, and meat samples were drilled from 990 cartons of frozen boneless beef. Carcass and boneless beef samples were respectively collected from 21 and 27 establishments that concentrated on export and from 38 and 3 establishments supplying the Australian domestic market of which 31 were very small plants slaughtering no more than 150 cattle equivalents per week. The mean log total viable counts (TVCs) were 2.42/cm2 and 2.52/g for carcasses and boneless meat, respectively. Escherichia coli was detected on 10.3% of carcasses and 5.1% of boneless beef samples and coagulase-positive staphylococci on 24.3% of carcasses and 17.5% of boneless beef. Salmonella was detected on 0.2% of carcasses and 0.1% of boneless beef and E. coli O157:H7 recovered from 0.1% of carcasses but not detected on 990 boneless beef samples. Mean log TVCs/cm2 differed significantly (P < 0.05) between establishment types. They were lower on carcasses from export establishments (2.20) compared with domestic (2.61) and very small plants (3.10). There were no significant differences in prevalence of Salmonella or E. coli O157:H7 between establishment types. Excision samples were taken from 670 carcasses to make comparisons with the first baseline study of Australian meat, carried out in 1993 to 1994. While there were differences in sampling and microbiological techniques between the two studies that require detailed consideration, there were small but significant improvements in several microbiological criteria for carcasses and boneless meat.

Abattoirs↗
PubMed2001

Microbiological quality of Australian sheep meat.

Microbiological quality of sheep carcasses and boneless sheep meat produced in Australia was surveyed during the period June to November 1998. Sponge samples were collected from 917 carcasses, and meat samples were drilled from 467 cartons of frozen boneless meat. Carcass and boneless meat samples were respectively collected from 7 and 10 establishments that concentrated on export, and from 36 and 5 establishments supplying the Australian domestic market of which 31 were very small plants slaughtering cattle and sheep but no more than 1,200 sheep equivalents per week. The mean log total viable counts were 3.55/cm2 and 3.30/g for carcasses and boneless meat, respectively. Escherichia coli was detected on 29.2% of carcasses and 24.5% of boneless meat samples and coagulase-positive staphylococci on 24.1% of carcasses, and 38.6% of boneless meat samples. Salmonella was detected on 0.1% of carcasses and 1.3% of boneless meat samples. E. coli O157:H7 was recovered from 0.7% of carcasses and 1.3% of boneless sheep meat. There were statistically significant differences between establishment types for some microbiological criteria, although there were no significant differences in prevalence of Salmonella or E. coli O157:H7 between establishment types. While there were differences in sampling and microbiological techniques between this study and another conducted in 1993 to 1994 that require detailed consideration, there were small but significant improvements in several microbiological criteria for boneless meat. While data that would allow for comparison of carcass data were not gathered, it is unlikely that improvements in the microbiological quality of boneless sheep meat could accrue without improvements to carcasses.

Abattoirs↗
PubMed2001

Detection of cocaine and its metabolites in breast milk.

A method was developed for measuring cocaine and its metabolites, benzoylecgonine, ecgonine methyl ester, norcocaine, ecgonine ethyl ester, cocaethylene, and m-hydroxybenzoylecgonine, in breast milk by gas chromatography/mass spectrometry. Limits of detection for this method ranged from 2.5 to 10 ng/mL, and limits of quantitation ranged from 5 to 50 ng/mL. For each of the compounds measured by this method, linear response was demonstrated to 750 ng/mL. Breast milk was collected from 11 mothers who admitted to drug use during pregnancy and ten drug-free volunteers serving as control subjects. Cocaine was detected in six of the specimens obtained from drug-exposed subjects, and in none of the drug-free control subjects. In breast milk specimens where cocaine and one or more of its metabolites were detected, the concentration of parent compound was greater than any of the metabolites. The highest cocaine concentration found was over 12 microg/mL. Breast-fed infants of cocaine abusing mothers may be exposed to significant amounts of drug orally.

Adult↗