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Biomedical subjects

J Oliver

Publications and source records attributed to J Oliver.

At least 37 records · Page 2Linked to original sources
PubMed2002

Using the Web to aid biochemists and microbiologists: an example of computer-based learning using PCR as an example.

The aim of this study was two-fold: to make available to the medical community a fast, efficient tool for troubleshooting PCR problems, and to demonstrate that hypermedia allow one to approach this kind of problem in a new, more useful way. The Web provides access to an enormous amount of information in the medical area, and in particular enables troubleshooting of new techniques in the medical laboratory. Currently it is possible to find textual information but it is not always easy to find hypermedia information. In many cases authors change only the means of dissemination of a book or paper to the Web, but do not adapt the information to the features of this new medium. The prototype of our hypermedia application was developed using Director and Flash programs (Macromedia), the application was developed from a decision tree built as a result of information compiled from expert PCR users and the existing literature. It was implemented on a website using Dreamweaver (Macromedia). The usefulness and possibilities of this application have been tested with physicians, medical laboratory technicians, and health science students, and have been proven to be more effective than traditional methods, both in education processes and in helping researchers and medical laboratory technicians in their daily work. The advance and popularization of the Internet in the medical profession requires information on the Web to adapt to the advantages offered by hypermedia. This new step must be taken, and the Web must offer medical users not only a different medium of information distribution but also a new way of handling and obtaining information.

Biochemistry↗
PubMed2001

Decreased expression of catenins (alpha and beta), p120 CTN, and E-cadherin cell adhesion proteins and E-cadherin gene promoter methylation in prostatic adenocarcinomas.

BACKGROUND: Catenin/E-cadherin complex proteins play an important role in cell-cell adhesion with decreased expression correlating with adverse prognostic variables in several human malignancies. METHODS: Archival formalin fixed, paraffin embedded (FFPE) sections from 118 prostatic adenocarcinomas (PACs) were immunostained by an automated method (Ventana Medical Systems, Tuscon, AZ) using monoclonal antibodies to catenins alpha and beta, p120 CTN, and E-cadherin proteins. Immunoreactivity was semiquantitatively graded, and results correlated with traditional prognostic parameters. In a subset of 10 randomly selected cases, E-cadherin gene promoter methylation status was determined on FFPE tissues using sodium bisulfite/hydroquinone DNA modification and polymerase chain reaction (PCR) with methylation specific primers (CpG wiz E-cadherin methylation assay; Intergen Co., Purchase, NY). RESULTS: Decreased expression of alpha-catenin (17%), beta catenin (4%), p120 CTN (45%), and E-cadherin (25%) proteins was noted in PACs with downregulation of each protein correlating with high tumor grade (P = 0.01-0.0001). In addition, p120 CTN and E-cadherin expression levels correlated with pathologic stage (P = 0.05; P = 0.02), aneuploidy (P = 0.001; P = 0.0001), and alpha-catenin with aneuploidy (P = 0.0001). p120 CTN loss also correlated with preoperative serum prostate specific antigen (P = 0.05). Two of 10 cases featured no evidence of E-cadherin gene promoter methylation by PCR and both cases retained expression of E-cadherin protein on immunohistochemistry. Of the 8 cases that showed E-cadherin methylation, 5 (68%) featured loss of expression of the protein on immunohistochemistry (P = 0.11). There was no correlation between E-cadherin methylation and adverse prognostic variables. CONCLUSIONS: Decreased expression of catenin/E-cadherin complex cell adhesion proteins is associated with aggressive phenotype in prostatic adenocarcinoma. E-cadherin gene promote methylation is a common event in prostate carcinoma but does not appear to bear prognostic significance in the subset of cases analyzed.

Adenocarcinoma↗
PubMed2001

Benefits of collaborative learning for environmental management: applying the integrated systems for knowledge management approach to support animal pest control.

Resource management issues continually change over time in response to coevolving social, economic, and ecological systems. Under these conditions adaptive management, or "learning by doing," offers an opportunity for more proactive and collaborative approaches to resolving environmental problems. In turn, this will require the implementation of learning-based extension approaches alongside more traditional linear technology transfer approaches within the area of environmental extension. In this paper the Integrated Systems for Knowledge Management (ISKM) approach is presented to illustrate how such learning-based approaches can be used to help communities develop, apply, and refine technical information within a larger context of shared understanding. To outline how this works in practice, we use a case study involving pest management. Particular attention is paid to the issues that emerge as a result of multiple stakeholder involvement within environmental problem situations. Finally, the potential role of the Internet in supporting and disseminating the experience gained through ongoing adaptive management processes is examined.

Animals↗
PubMed2001

Nuclear transfer protocol affects messenger RNA expression patterns in cloned bovine blastocysts.

The successful production of embryos by nuclear transfer (NT) employing cultured somatic donor cells depends upon a variety of factors. The objective of the present study was to investigate the effects 1) of two different activation protocols, 2) the use of quiescent or nonquiescent donor cells (G(0) or G(1) of the cell cycle), and 3) passage number of donor cells on the relative abundance (RA) of eight specific mRNAs (DNA methyltransferase, DNMT; mammalian achaete-scute homologue, Mash2; glucose transporter-1, Glut-1; heat shock protein 70.1, Hsp; desmocollin II, Dc II; E-cadherin, E-cad; interferon tau, IF; insulin-like growth factor 2 receptor, Igf2r) in single blastocysts employing a semiquantitative reverse transcription-polymerase chain reaction assay. The results were compared with those for their in vitro (IVP)- and in vivo-generated noncloned counterparts. In experiment 1, employing either FBA (fusion before activation) or AFS (fusion and activation simultaneously) to generate NT blastocysts, Hsp mRNAs were not found in NT embryos from either protocol, whereas Hsp transcripts were detectable in IVP embryos. The relative abundance (RA) of IF transcripts was significantly increased in the AFS and IVP groups compared to the FBA treatment. In experiment 2, the use of either G(0) or G(1) donor cells to produce cloned embryos both significantly reduced the relative amount of DNMT transcripts and significantly increased the RA of Mash2 compared to the IVP embryos. In addition, IF transcript levels were significantly elevated in NT blastocysts employing G(1) donor cells for NT compared to IVP embryos and those generated using G(0) cells. In experiment 3, donor cells, either from passsage 5/6 or 8, were employed for NT. DNMT transcripts were significantly decreased, whereas Mash2 transcripts were significantly increased in both NT groups compared to their IVP counterparts. The amount of IF mRNA was significantly higher in P8-derived than in P5/6 and IVP embryos. In experiment 4, the RA of DNMT transcripts was decreased in in vivo-derived blastocysts compared to those produced in vitro. Mash2 expression was increased in in vivo embryos and those IVP embryos produced in medium containing Sigma BSA. The RA of Hsp was higher in IVP embryos produced in serum containing medium than in those produced in Sigma BSA or in vivo. In vivo embryos and those produced in Life Technologies BSA had the lowest expression of IF transcripts. Expression of all other genes was not affected by variation in NT methodology or IVP culture systems throughout experiments 1-4. In conclusion, depending on steps of the cloning procedure NT-derived embryos display marked differences from their IVP- and in vivo-derived counterparts. An aberrant expression pattern in NT embryos was found with respect to genes thought to be involved in stress adaptation, trophoblastic function, and DNA methylation during preimplantation development.

Animals↗
PubMed2001

Audit and non-principals: reported experiences in general practice.

OBJECTIVES: To determine respondents reported levels of exposure to audit during their medical career and as a general practice non-principal. To assess and identify audit education and training needs. DESIGN: Postal questionnaire survey. SETTING: The West of Scotland. SUBJECTS: Two hundred GP non-principals. RESULTS: A response rate of 79% was achieved. The mean age of respondents was 35 years and 121 (77%) were female. One hundred and thirty respondents (83%) reported involvement in three or less audit projects during a mean career length of 12.1 years. Of 378 audit projects claimed to have been undertaken, 287 (76%) involved setting measurable standards, and 181 (48%) failed to be completed. One hundred and six respondents (68%) had yet to take part in audit during their time as a non-principal (median length of time was 1 year). Thirty nine respondents (25%) were currently involved in an on-going audit project. One hundred and twelve (71%) claimed that they were not expected to participate in audit as part of their current or previous non-principal post. One hundred and one respondents (64%) indicated that they require further education and training in audit method. CONCLUSIONS: Non-principals' experience of audit and exposure to it are poor. Many lack knowledge of audit method and appear to be uninvolved in audit and excluded from local audit programmes. Integration into the primary care team, access to a co-ordinated programme of audit and training in audit method are required. Otherwise non-principals may continue to struggle with the audit demands of clinical governance and impending revalidation.

Adult↗
PubMed2000

Chromatographic determination of carotenoids in foods.

In recent years, there has been particular emphasis on obtaining more accurate data on the types and concentrations of carotenoids in foods for various health and nutrition activities. The analysis of carotenoids is complicated because of the diversity and the presence of cis-trans isomeric forms of this group of compounds. In addition, a wide variety of food products of vegetal and animal origin, vegetables and animal samples contain carotenoids, and a great range of carotenoids can be found in these samples. The characteristic conjugated double bond system of carotenoids produces the main problem associated with work and manipulation on carotenoids, that is their particular instability, especially towards light, heat, oxygen and acids. For this reason, several precautions are necessary when handling carotenoids. Another problem associated with analysis of carotenoids is the difficulty in obtaining standard compounds. High-performance liquid chromatographic methods for the determination of carotenoids in foods are reviewed. The sample extraction and treatment, carotenoid purification and standard manipulation are briefly commented on. We present a critical assessment of chromatographic methods developed for the determination of carotenoids in foods. Finally, some methods for carotenoid ester separation are reviewed.

Carotenoids↗
PubMed2000

Cytokine and adrenal axis responses to endotoxin.

The push-pull cannula (PPC) technique was applied to examine the kinetics of in vivo concentration changes in male rat brain extracellular fluid (ECF) of endogenous interleukin-1beta (IL-1beta) and corticotrophin releasing hormone (CRH) after a peripheral injection of lipopolysaccharide (LPS) (25 microg/100 g b.wt. intravenously). In addition, IL-1beta, adrenocorticotropin hormone (ACTH) and corticosterone concentrations in plasma were also measured at selected intervals after LPS challenge. Administration of LPS resulted in a progressive increase in the concentrations of IL-1beta in brain hypothalamic ECF. A significant increase from the zero time mean value of 77+/-10 to 393+/-88 pg/ml at the 15-min interval was recorded. The increase in IL-1beta concentration in hypothalamic ECF reached a peak of 883+/-237 pg/ml at 30 min post-LPS. CRH concentration in the same hypothalamic ECF was 41+/-17 pg/ml at time zero, 97+/-15 pg/ml at 15 min and at 30 min was significantly increased (215+/-56 pg/ml). A time course of significant increases at 30 min in plasma concentrations of IL-1beta, ACTH and corticosterone was also recorded in the same animals described above. The data show that a peripherally administered LPS bolus elicited an early (over 15 min post-injection) increase in brain ECF IL-1beta concentration; additional significant increases in hormones released from the hypothalamic-pituitary-adrenal (HPA) axis were recorded at 30 min post-LPS injection. These observations support the concept of an early change in hypothalamic ECF concentration of IL-1beta preceding LPS-induced activation of the HPA axis.

Adrenocorticotropic Hormone↗
PubMed2000

Secretory granules of endocrine and chief cells of human stomach mucosa contain leptin.

BACKGROUND: Leptin plays an important role in the control of food intake and body weight homeostasis. In humans, leptin is produced by adipocytes, placental cells and secretory cells of the mammary epithelium. Recently, it has been reported that stomach glands produce leptin in rats. OBJECTIVE: To test the expression of leptin protein in human stomach and localize, by immunocytochemistry, the specific cell type producing leptin. DESIGN: Endoscopic stomach biopsies of six patients were used to investigate leptin production in the fundic epithelium using reverse transcription polymerase chain reaction (RT-PCR) of RNA. Leptin protein was detected by immunoblot analysis and localized by immunohistochemistry and ultrastructural immunocytochemistry (immunogold method). RESULTS: Human gastric epithelium expresses leptin mRNA and leptin protein. The cells in the lower half of the stomach glands were immunoreactive for leptin. Ultrastructural immunocytochemistry showed leptin immunoreactivity in the pepsinogen granules of chief cells, but the granules of a specific endocrine cell type in the basal portion of the glands were also positive. CONCLUSIONS: Our results suggest that gastric leptin could function in the short-term system to control feeding behaviour and is probably secreted in the stomach lumen by chief cells and into the stomach circulation by a special type of endocrine cell.

Adult↗
PubMed2000

Insulin infusions in the neonatal unit: delivery variation due to adsorption.

OBJECTIVE: To assess the extent of the variability in insulin delivery over time, under conditions used in Australian neonatal units, studying the following variables: diluent, preconditioning, flushing, sequential preconditioning and flushing, insulin concentration, flow rate, catheter type, and addition of albumin. METHODOLOGY: A range of simulated insulin infusions was studied. Infusions were run over 22 h, with aliquots of infusate collected at baseline and after 15 min, 30 min, 1 h, 2 h, 6 h and 22 h. Insulin concentration was assayed using a radioimmunoassay. RESULTS: An infusion of 50 mU insulin/mL at 1 mL/h gave negligible insulin delivery until 22 h. However, after preconditioning and flushing the tubing, consistent insulin delivery was attained by 6 h. An infusion of 200 mU insulin/mL at 1 mL/h did not provide consistent delivery until 6 h. At this concentration and rate, consistent insulin delivery was attained within 30 min of the start of the infusion either by preconditioning and flushing the tubing, or by addition of albumin to the infusate. CONCLUSION: Clinically significant variation in intravenous insulin delivery will occur in the neonatal setting unless counter-measures are taken, such as sequential preconditioning and flushing of the delivery system or the addition of albumin to the infusate.

Adsorption↗
PubMed2000

Carboxylesterases, a key factor in evaluating potential genotoxicity of Trinem antibiotics.

Sanfetrinem cilexetil, a hexetil ester of a Trinem antibiotic, does not induce micronuclei in rat bone marrow cells or induce DNA repair synthesis in rat hepatocytes following oral dosing. However, in vitro chromosome damage and mutations are induced in mammalian cells lacking carboxylesterase activity (human lymphocytes and mouse lymphoma L5178Y cells). In cells possessing carboxylesterase activity (CHL cells), chromosome damage induced by Sanfetrinem cilexetil is not observed. Similarly, if induced rat liver preparations or non-induced preparations from rat or human intestinal cells are present during exposure, genotoxic activity is lost, even in those cells lacking carboxylesterase enzymes. Thus the lack of demonstrable genotoxicity in vivo, in the assays used, is likely to be due to hydrolysis of the parent molecule by non-specific carboxylesterases present within the intestinal epithelium. In turn this data indicates that a genotoxic hazard to humans under therapeutic conditions is unlikely.

Animals↗
PubMed2000

Opposite effects of feeding a vitamin A-deficient diet and retinoic acid treatment on brown adipose tissue uncoupling protein 1 (UCP1), UCP2 and leptin expression.

The relationship between interscapular brown adipose tissue (IBAT) thermogenic potential and vitamin A status was investigated by studying the effects of feeding a vitamin A-deficient diet and all-trans retinoic acid (tRA) treatment on body weight and IBAT parameters in mice. Feeding a vitamin A-deficient diet tended to trigger opposite effects to those of tRA treatment, namely increased body weight, IBAT weight, adiposity and leptin mRNA expression, and reduced IBAT thermogenic potential in terms of uncoupling protein 1 (UCP1) mRNA and UCP2 mRNA expression. The results emphasize the importance of retinoids as physiological regulators of brown adipose tissue.

Adipose Tissue, Brown↗
PubMed2000

Potential for New York mosquitoes to transmit West Nile virus.

We evaluated the potential for several North American mosquito species to transmit the newly introduced West Nile (WN) virus. Mosquitoes collected in the New York City Metropolitan Area during the recent (1999) WN outbreak were allowed to feed on chickens infected with WN virus isolated from a crow that had died during this outbreak. These mosquitoes were tested approximately 2 weeks later to determine infection, dissemination, and transmission rates. Culex pipiens mosquitoes were highly susceptible to infection, and nearly all individuals with a disseminated infection did transmit WN virus by bite. In contrast, Aedes vexans were only moderately susceptible to oral infection; however, those individuals inoculated with WN virus did transmit virus by bite.

Animals↗
PubMed2000

Studies on the growth of Escherichia coli O157:H7 strains at 45.5 degrees C.

The objectives of the present report were to examine the ability of 18 strains of Escherichia coli O157:H7 to grow in EC broth at 42.4, 43.5, 44.5, and 45.5 degrees C, and to document the incidence of phenotypic variants present in low numbers that are capable of growth at 45.5 degrees C in EC broth. Among the 18 strains of E. coli O157:H7 studied, only 3 were capable of producing turbid growth with gas formation in EC broth at 45.5 degrees C with 1 x 10(2) initial CFU/ml. Higher initial densities of CFU resulted in turbid growth and gas formation in EC broth at 45.5 degrees C with all strains. The presence of bile salts #3 in EC broth was found to be inhibitory at 45.5 degrees C. All 18 strains were found to be capable of growth at 45.5 degrees C in nonselective media. The ability of at least one sensitive strain to grow in EC broth at 45.5 degrees C was found to be dependent on the initial number of CFU/ml. Prior growth of cells of a sensitive strain in EC broth at 45.5 degrees C from a cell density of 2.0 x 10(7) to 8.0 x 10(7) CFU/ml followed by removal of cells and reinoculation at a cell density of 2.0 x 10(6) CFU/ml resulted in growth at 45.5 degrees C that did not occur without such conditioning of the inhibitory medium. These results indicate that the ability of most strains of E. coli O157:H7 to grow in EC broth at 45.5 degrees C is dependent on the initial density of CFU and that at low densities of CFU the ability to initiate growth is dependent on either low numbers of phenotypic variants tolerant to the presence of bile salts #3 in EC broth at 45.5 degrees C or to conditioning of the medium with prior elevated numbers of cells.

Bile Acids and Salts↗
PubMed2000

Development of a new lysis solution for releasing genomic DNA from bacterial cells for DNA amplification by polymerase chain reaction.

A new lysis solution designated TZ, consisting of 2.0% Triton X-100 plus 2.5 mg sodium azide/ml in 0.1 M Tris-HCl buffer at pH 8.0, yielded higher levels of genomic DNA from Escherichia coli O157:H7 cells compared with a number of other commonly used cell lysis methods. Ethidium bromide stained DNA bands resulting from PCR amplification of target DNA from 100 CFU of E. coli O157:H7 were readily detected following electrophoresis of agarose gels. In contrast, conventional cell lysis methods failed to detect target DNA from 100 CFU after PCR amplification. The new solution was highly effective for lysing cell suspensions of Salmonella enteritidis, Pseudomonas putida, Lysteria monocytogenes and Psychrobacter immobilis.

Buffers↗