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Biomedical subjects

D Peters

Publications and source records attributed to D Peters.

At least 55 records · Page 3Linked to original sources
PubMed1998

Characterization of petunia flower mottle virus (PetFMV), a new potyvirus infecting Petunia x hybrida.

With the introduction of cutting-grown Petunia x hybrida plants on the European market, a new potyvirus which showed no serological reaction with antisera against any other potyviruses infecting petunias was discovered. Infected leaves contained flexuous rod-shaped virus particles of 750-800 nm in length and inclusion bodies (pinwheel structures) typical for potyviruses in ultrathin leaf sections. The purified coat protein with a Mr of approximately 36 kDa could be detected in Western immunoblots with a specific antibody to the coat protein of the petunia-infecting virus. The 3' end of the viral genome encompassing the 3' non-coding region, the coat protein gene, and part of the NIb gene was amplified from infected leaf material by IC/PCR using degenerate and specific primers. Sequences of PCR-generated cDNA clones were compared to other known sequences of potyviruses. Maximum homology of 56% was found in the 3' non-coding region between the petunia isolate and other potyviruses. A maximum homology of 69% was found between the amino acid sequence of the coat protein of the petunia isolate and corresponding sequences of other potyviruses. These data indicate that the petunia-infecting virus is a previously undescribed potyvirus and the name petunia flower mottle virus (PetFMV) is suggested.

Amino Acid Sequence↗
PubMed1997

Fibroblast growth factor 2, heparin and suramin reduce epithelial ulcer development in experimental HSV-1 keratitis.

BACKGROUND: We have previously shown that basic fibroblast growth factor (FGF-2) enhances corneal epithelial healing in different experimental models in vivo. In order to study the healing effect of this growth factor in pathological conditions of the cornea, we investigated whether topical application of FGF-2 could affect herpes keratitis in rabbits. Since HSV-1 infection is prevented in vitro by incubation with heparin, we also topically applied heparin and suramin, considering the similar interaction of herpes simplex virus and FGF-2 with cell membrane-anchored heparan sulfate. METHODS: After virus inoculation with a human BEY.2 strain, rabbits were treated with either FGF-2 (200 ng to 2 micrograms/application), heparin (250 micrograms/application) or suramin (250 micrograms/application) 4 times daily until day 14. Acyclovir and placebo administrations served as controls (n = 48 rabbits). Computerized ulcer surface analysis, clinical observations and virus recovery assays were performed. RESULTS: Topical FGF-2, heparin and suramin treatment revealed a significant reduction in peak ulcer sizes, and complete epithelial healing was achieved earlier than in placebo-treated corneas. However, no significant antiviral effect of FGF-2, heparin and suramin was detectable in plaque assays from conjunctival swabs. CONCLUSIONS: These experiments demonstrate that FGF-2 is effective in promoting herpetic epithelial ulcer healing, either due to its proliferative effects on epithelial cells or indirectly by occupying the sites on cell surface heparan sulfate necessary for the attachment of the virion. The latter mechanism of action is presumably the reason for the similar effect of heparin and suramin.

Acyclovir↗
PubMed1997

Serological comparison of tospoviruses with polyclonal antibodies produced against the main structural proteins of tomato spotted wilt virus.

A new purification procedure for the tospoviruses of serogroups II and III was developed. SDS-polyacrylamide gel electrophoresis of purified tomato spotted wilt virus (TSWV; serogroup I), groundnut ringspot virus (GRSV: serogroup II), tomato chlorotic spot virus (TCSV; serogroup II) and impatiens necrotic spot virus (INSV; serogroup III) showed that the glycoprotein G2 of serogroup II members differs significantly in size from that of the serogroup I virus. Western immunoblot analysis using polyclonal antisera produced against purified glycoproteins TSWV-G1 and G2 as well as peptides of hydrophilic sequences of TSWV-G1 and G2 expressed in Escherichia coli demonstrated a higher homology amongst G1 of different serogroups than for G2. These results are supported by comparing the glycoprotein gene sequences of different serogroups.

Antibodies, Viral↗
PubMed1997

Multiplication of tomato spotted wilt virus in primary cell cultures derived from two thrips species.

Primary cell cultures prepared from embryos of the thrips species Frankliniella occidentalis and Thrips tabaci were tested for their potential to support replication of tomato spotted wilt virus (TSWV). Using polyclonal antibodies against the viral nucleocapsid protein (N) and indirect immunofluorescent staining, discrete spots with strong signals were observed in the cytoplasm at 48 h post-inoculation in the cell cultures of a F. occidentalis, and a T. tabaci population which failed to transmit the virus. The infection was found in approximately 40% of the monolayer cells. Using antibodies against a nonstructural protein (NSs) of TSWV, uniform and more diffused staining was observed throughout the cytoplasm of these cells, underlying active genome replication. The NSs protein accumulated slower than the N protein in the cells of both thrips species. No multiplication of TSWV was observed in a heterologous insect cell line, i.e. from Spodoptera frugiperda, suggesting the existence of specific host factors in the thrips-derived cells.

Animals↗
PubMed1997

Enhanced cyclooxygenase-2 gene expression in alcoholic liver disease in the rat.

BACKGROUND & AIMS: Inflammatory stimuli and lipid peroxidation up-regulate cyclooxygenase (COX)-2. This study evaluated the relationship between inflammatory mediators, COX expression, and pathological changes in experimental alcoholic liver disease. METHODS: Rats (5 per group) were fed ethanol and a diet containing saturated fat, corn oil, or fish oil by intragastric infusion. Dextrose isocalorically replaced ethanol in controls. In the first set of experiments, whole livers were analyzed. In the second set of experiments, Kupffer cells, endothelial cells, and hepatocytes were isolated from rats in each group. Pathological analyses and measurements of lipid peroxidation, tumor necrosis factor (TNF)-alpha, COX-1 and COX-2 messenger RNA (mRNA), endotoxin, and liver and plasma thromboxane were performed. RESULTS: Increased expression of COX-2 mRNA was detected in the livers of rats showing necroinflammatory changes. The Kupffer cell was the cell primarily responsible for the increase in COX-2 mRNA level. Increased expression of COX-2 was associated with increased levels of endotoxin, TNF-alpha mRNA, lipid peroxidation, and synthesis of thromboxane. COX-1 mRNA was decreased in Kupffer cells in rats with the most severe liver injury. CONCLUSIONS: Up-regulation of COX-2 in alcoholic liver injury occurred in the presence of proinflammatory stimuli and resulted in increased synthesis of inflammatory and vasoactive eicosanoids. Down-regulation of COX-1 may result in decreased synthesis of cytoprotective eicosanoids and additionally exacerbate liver injury.

Animals↗
PubMed1997

Population predictors of community health and social service use in Northern Ireland.

STUDY OBJECTIVE: To investigate the characteristics of elderly populations associated with variations in their use of community health and personal social services and to test the hypotheses that the variations are related to: (a) the age structure of an elderly population; (b) the population's socioeconomic composition, including the level of deprivation; and (c) household or living arrangements. DESIGN: A common file of 1991 population census and 1994 NHS community trust operational variables was constructed for 67 postcode sectors, with the independent variables describing the age-sex groups to be studied. Clear criteria for the exclusion of "empty" sectors were developed. Relationships using bivariate and multivariate correlation and stepwise multiple regression were explored. SETTING: Eastern Health and Social Services Board area, Northern Ireland (Belfast and hinterland). PARTICIPANTS: Population of statutory pensionable age; in aggregate, younger and older age bands. MAIN RESULTS: The age structure or mean age of the elderly population had only a weak association with the community health and social service client rate, but there were strong associations with socio-economic variables, particularly the percentage of those living alone who were without a car and the percentage of pensioner households that included an adult of below pensionable age. Parsimonious multiple regression models accounted for between 46% and 80% of the variation in the NHS community trust client rate. Greater explanations were achieved for the young elderly population than for those aged 75+ years and, when the population was divided between young and old age bands, for men than for women. CONCLUSIONS: Community health and social services for elderly people in eastern Northern Ireland were focused on those with a low income and those who were not co-resident with adults of working age. When local elderly populations are compared, per capita morbidity and dependency are often higher where the mean age is low, and vice versa, because of the inverse relationship between socioeconomic status and survival in old age. Capitation scales for resource allocation with positive age weighting will be of little use if no account is taken of the relative prevalence of need in the youngest or base age group.

Age Distribution↗
PubMed1997

A natural classification of alcoholics by means of statistical grouping methods.

AIMS: The results of previous studies using statistical grouping methods for subtyping of alcoholics did not converge to a coherent natural classification, probably among other things as a consequence of improper selection of methods. As an alternative an analytic strategy is formulated and tested. First, a cluster procedure tests a categorical model of the data. If no compact isolated groups are detected non-metric multi-dimensional scaling is used to unravel the complex relations in the data by reconstructing a low dimensional spatial solution. DESIGN: Cross-sectional study. SETTING: In and outpatient treatment programs of the Amsterdam health region in The Netherlands. PARTICIPANTS: A consecutive sample of 277 men and women voluntarily seeking treatment for their alcohol problems. No exclusion criteria were applied. MEASUREMENTS: A sample of 102 symptoms reflecting various aspects of alcoholism measured by structured self-report questionnaire (93 symptoms) or derived from a semi-structured interview taken by treatment staff (nine symptoms). FINDINGS: The cluster procedure failed to show a fitting categorical model. Non-metric multi-dimensional scaling produced a three-dimensional spatial solution. The first dimension reflects the alcohol dependence syndrome. The second bipolar dimension reveals a male-dominated anti-social alcoholism, and a female-dominated pattern of isolated home drinking. The third bipolar dimension represents chronic alcoholism, and young quarrelsome people from troubled families. CONCLUSIONS: The three-dimensional solution obtained has a high face validity and incorporates a number of aspects of previous classifications. The results illustrate the strength of the analytic strategy in unravelling complex symptomatology. Limitations of the classification obtained are stressed and directions for subsequent validation research are given.

Adult↗
PubMed1996

Isolated polycystic liver disease as a distinct genetic disease, unlinked to polycystic kidney disease 1 and polycystic kidney disease 2.

Polycystic liver disease (PLD) is proven to occur either sporadically or in association with autosomal dominant polycystic kidney disease (ADPKD), whereas the existence of an isolated (i.e., without any kidney cyst) familial form is disputed. We describe a family with definitely isolated PLD transmitted through three generations and exclude the linkage of the disease to the genetic markers of PKD1 and PKD2, the two main loci responsible for ADPKD. These findings strongly support the existence of PLD as a genetic disease distinct from the known forms of ADPKD.

Cysts↗
PubMed1995

The nonstructural NSm protein of tomato spotted wilt virus induces tubular structures in plant and insect cells.

The expression and subcellular location of the 33.6-kDa nonstructural protein NSm of tomato spotted wilt virus (TSWV) was analyzed in Nicotiana rustica plants and protoplasts as a function of time. Immunofluorescent studies in protoplasts isolated from TSWV-infected N. rustica leaves showed that this protein could first be detected close to the periphery of the cell, near the plasmamembrane, and later in tubular structures emerging from the cell surface. In situ, these tubules appeared specifically in the plasmodesmata, suggesting their involvement in cell-to-cell movement of the virus during systemic infection. In protoplasts transfected with an expression vector containing the NSm gene, similar tubules were formed, indicating that NSm has the ability to form these structures in the absence of other virus-specific components. To test whether plant-specific components were involved in tubule formation, the NSm gene was also expressed in a heterologous expression system, i.e., insect cells. Spodoptera frugiperda and Trichoplusia ni cells were infected with a recombinant baculovirus expressing the NSm-gene (AcNPV/NSm). The efficient formation of NSm-containing tubules emerging from the surface of both cell types indicate that no plant-specific cell structures or proteins are involved in their development.

Animals↗
PubMed1995

Lactose-specific enzyme II of the phosphoenolpyruvate-dependent phosphotransferase system of Staphylococcus aureus. Purification of the histidine-tagged transmembrane component IICBLac and its hydrophilic IIB domain by metal-affinity chromatography, and functional characterization.

The lactose-specific integral-membrane-protein enzyme II (IICBLac) of the bacterial phosphoenolpyruvate-dependent phosphotransferase system of Staphylococcus aureus catalyses the uptake and phosphorylation of lactose. It consists of an N-terminal membrane-spanning IIC domain and a C-terminal hydrophilic IIB domain. IICBLac was fused with a C-terminal tag of six histidine residues using recombinant DNA technology. The resulting protein, IICBLac-His, was produced in Escherichia coli and purified under nondenaturing conditions to homogenity. The purification procedure consists of a NaOH extraction step followed by solubilisation with Triton X-100, and metal-affinity chromatography using Ni(2+)-nitrilotriacetic acid resin. The purified recombinant His-tagged protein possessed substrate specificity identical to that of the wild-type protein. To investigate the hydrophilic IIB domain, the DNA sequence coding for IIB and the His tag were fused in-frame to a DNA sequence specific for an initiation signal. The overproduced recombinant IIBLac-His was obtained by metal-affinity chromatography in pure form. Bacterial phosphotransferase-system-dependent phosphorylation of IIB-His was demonstrated in a photometric assay and by urea/polyacrylamide gel electrophoresis. The phosphorylation activity of the mutant protein [C476S]-IICBLac, containing the mutagenized phosphorylation site, was restored in the presence of IIBLac-His in a phosphorylation assay.

Base Sequence↗
PubMed1995

Semiautomated DNA probe mapping using digital imaging microscopy: II. System performance.

This paper describes an evaluation of a semiautomated, multicolor image-analysis system to map cloned probes along metaphase chromosomes. Mapping with this system consists of fluorescence in situ hybridization (FISH) for probe localization, automatic acquisition of multicolor images showing total chromosomal DNA and probe location(s), and automatic determination of the fractional locations of the probes along the chromosomes relative to the short arm telomere (FLpter). The system was evaluated by mapping ten phage and ten cosmid probes previously mapped to chromosome 3 with other procedures. The standard deviations of FLpter measurements averaged 3.4 Mb and 2.6 Mb for phage and cosmid probes, respectively. With this variation, the order of two probes mapped in separate hybridizations could be determined with 95% confidence when their separation was greater than 2.5 Mb. In all cases, the probe locations and order were consistent with previous mapping data. FLpter values were converted to band locations using measurements of the band locations made using digital imaging microscopy. This proved superior to conversions made using ISCN ideograms.

Bacteriophages↗
PubMed1995

Autosomal dominant polycystic kidney disease: evidence for the existence of a third locus in a Portuguese family.

Autosomal dominant polycystic kidney disease is characterized by clinical and genetic heterogeneity. Two loci implicated in the disease have previously been mapped (PKD1 on chromosome 16 and PKD2 on chromosome 4). By two point and multipoint linkage analysis, negative lod scores have been found for both chromosome 16 and chromosome 4 markers in a large Portuguese family, indicating that a third PKD locus is involved in the development of the disease.

Chromosome Mapping↗
PubMed1995

Distribution of antibodies to porcine circovirus in swine populations of different breeding farms.

An enzyme linked immunosorbent assay (ELISA) was developed for mass antibody screening to porcine circovirus (PCV) in pig herds of different age groups and of different husbandries. Infection with PCV was found to be common in all swine herds tested, with only one exception, a herd at a small farm. Statistically, the percentage of PCV negative sera decreased and titer levels increased with increasing age of the pigs. Within individual age groups, differences were found to exist between different husbandries. No correlation was detected between antibody levels and reproductive disorders in the herds.

Age Factors↗
PubMed1995

Presence of antibodies reacting with porcine circovirus in sera of humans, mice, and cattle.

Antibodies reacting with porcine circovirus (PCV) were found in sera of humans, mice, and cattle by means of an indirect immunofluorescence assay (IFA) and an ELISA. In man, the highest seroprevalence (23.9% in IFA and 30.2% in ELISA) was found among hospitalized patients with fever of partially unclear etiology. Non-hospitalized "healthy" persons of the former German Democratic Republic showed a significantly higher number of positive sera (IFA = 20%) than blood donors from Berlin-West (IFA = 8.6%). Murine sera reacted positive with PCV in IFA between 12 to 69% in different breeding groups and about 35% of cattle sera were found reactive with PCV in IFA. Double-staining IFAs, immuno-electron microscopy and immunoblotting showed that non-porcine antibodies reacted with PCV structural antigen. Mathematical analysis revealed that in ELISA, non-porcine antibodies reacted specifically with PCV. Loss of binding specificity of non-porcine antibodies in ELISA after storage of sera and lower maximal optical densities obtained at equal titers in ELISA with non-porcine than with porcine sera suggest that antibodies in man, mice and cattle are caused by related species specific viruses sharing antigenic epitopes with PCV.

Adult↗
PubMed1995

Occurrence and role of an early antigen and evidence for transforming ability of porcine circovirus.

By means of indirect immunofluorescence assay (IFA) using natural swine immune serum and hyperimmune serum from rabbits infected with porcine circovirus (PCV), a PCV antigen was detected present prior to the onset of viral and cellular DNA synthesis in nucleoli of cells of synchronized and growth stimulated infected PS cell cultures grown for more than 12 h in the presence of hydroxyurea. The number of cells containing specifically fluorescing nucleoli increased with increasing time of growth in the presence of hydroxyurea. The concomitant increase in the number of cells containing virus structural (VS) antigen in the nuclei and the increase in the amount of replicative (RF) DNA and accompanying 5 S DNA after release from the hydroxyurea block suggest that EA is involved in induction of PCV DNA replication. Primary pig kidney cell cultures persistently infected with PCV survived mock-infected control cultures for 16 passages. They had lost contact inhibition and formed cell colonies in soft agar at a ratio of 0.1 to 0.4%. Cell lines derived from agar colonies showed properties of transformed cells e.g. low requirement for serum growth factors, ability to overgrow a continuous cell layer, anchorage independence of growth. In transformed cells stimulated to growth and grown in the presence of hydroxyurea, non-structural viral antigen visible by IFA in nucleoli and VS antigen located in the cytoplasm were expressed. Contrary to virus bound nuclear VS antigen in productive infection, accumulation of cytoplasmatic VS antigen was independent of DNA synthesis and caused cell destruction, thus limiting growth of cell layers and colonies in soft agar.

Animals↗
PubMed1995

Pharmacological profile and anti-ischemic properties of the Ca(2+)-channel blocker NS-638.

Included in the sequence of events leading to neuronal death in ischemic tissue following stroke is an excessive and toxic rise in the intracellular Ca(2+)-concentration, predominantly due to an influx of Ca2+ through nonselective cation-channels as well as Ca(2+)-channels. In the present study we have characterized the pharmacological profile and anti-ischemic effects of 2-amino-1-(4-chlorobenzyl)-5-trifluoromethylbenzimidazole (NS-638), a small nonpeptide molecule with Ca(2+)-channel blocking properties. NS-638 dose dependently inhibited K(+)-stimulated [45Ca2+]-uptake in chick cortical synaptosomes and 2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA)-stimulated [3H]GABA-release from cultured cortical neurons with IC50 values of 2.3 and 4.3 microM, respectively. K(+)-stimulated intracellular Ca(2+)-elevation in cultured cerebellar granule cells was equipotently blocked with an IC50 value of 3.4 microM. At this concentration no effect on Ca(2+)-induced contractions in K(+)-depolarized guinea pig taenia coli was observed. The effect of NS-638 on neuronal Ca(2+)-channels was evaluated using whole cell patch clamp techniques. The compound reversibly blocked N- and L-type Ca(2+)-channels in cultured chick dorsal root ganglion cells in the concentration range of 1-30 microM. In the mouse middle cerebral artery occlusion (MCAO) model, NS-638 administered i.p. (50 mg kg-1) at 1 h and 6 h post-ischemia, and once a day for the next two days, resulted in a 48% reduction in total infarct volume. The compound did not show protection against ischemic neuronal damage in the gerbil model of bilateral carotid artery occlusion (BCAO). This data suggests, that neuronal Ca(2+)-channel blockers may have potential in ameliorating the pathological damage after focal ischemia.

Animals↗
PubMed1994

Expression and subcellular location of the NSM protein of tomato spotted wilt virus (TSWV), a putative viral movement protein.

The 33.6-kDa nonstructural (NSM) protein gene, located on the ambisense M RNA segment of tomato spotted wilt virus (TSWV), was cloned and expressed using the Escherichia coli pET-11t expression system. The protein thus produced was purified and used for the production of a polyclonal antiserum. Western immunoblot analyses of TSWV-infected Nicotiana rustica plants showed NSM synthesis only during a short period early in systemic infection. Although NSM was found associated with cytoplasmic nucleocapsid preparations, it was absent from purified virus particles. Analyses of subcellular fractions from young, systemically infected leaves showed the presence of NSM in fractions enriched for cell walls and cytoplasmic membranes, respectively. Furthermore, immunogold labeling of tissue sections of TSWV-infected N. rustica plants showed that this protein was found associated with nucleocapsid aggregates in the cytoplasm and in close association with plasmodesmata. The data obtained provide evidence that NSM represents the viral movement protein of TSWV, involved in cell-to-cell movement of nonenveloped ribonucleocapsid structures.

Animals↗