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Biomedical subjects

G Stone

Publications and source records attributed to G Stone.

At least 19 recordsLinked to original sources
PubMed2006

Programmed cell death induced by Japanese encephalitis virus YL vaccine strain or its recombinant envelope protein in varied cultured cells.

OBJECTIVE: The Japanese encephalitis virus YL vaccine strain (JEV-YL) was investigated as regards its organ tropism and the role of recombinant envelope glycoprotein in the induction of apoptosis was explored. METHODS: Threevaried cell lines (HepG2, Vero and C6) were infected with JEV-YL or transfected with eukaryotic expression plasmids (pcE, pcF1R2, pcF1R1 and pcF2R2) which contain different parts of the envelope gene and phenotypic properties were examined by flow cytometry and DNA fragmentation analysis. RESULTS: After JEV-YL infection, smaller plaque was produced on HepG2 cells than on Vero cells, whereas no cytopathic effect was observed on C6 cells; moreover, by apoptosis and DNA fragmentation assays, the hallmark cytopathic effects were detected in HepG2 and Vero cells but not in C6 cells. Furthermore, cells used in our study transfected with recombinant core plasmid, pcE, which include full-length E gene but the deleted forms (pcF1R2, pcF1R1 and pcF2R2) did not have similar results as JEV-YLs. CONCLUSIONS: The JEV-YL vaccine strain had changed cell tropism to liver cells different from other virulent strains which have neural tropism, and in this study we proved that the transient-expressed entire E protein of JEV-YL could induce apoptosis and the mutations of E protein may change the organ tropism of JEV-YL.

Animals↗
PubMed2006

Multidirectional chromosome painting reveals a remarkable syntenic homology between the greater galagos and the slow loris.

We report on the first reciprocal chromosome painting of lorisoids and humans. The chromosome painting showed a remarkable syntenic homology between Otolemur and Nycticebus. Eight derived syntenic associations of human segments are common to both Otolemur and Nycticebus, indicative of a considerable period of common evolution between the greater galago and the slow loris. Five additional Robertsonian translocations form the slow loris karyotype, while the remaining chromosomes are syntenically equivalent, although some differ in terms of centromere position and heterochromatin additions. Strikingly, the breakpoints of the human chromosomes found fragmented in these two species are apparently identical. Only fissions of homologs to human chromosomes 1 and 15 provide significant evidence of a cytogenetic link between Lemuriformes and Lorisiformes. The association of human chromosomes 7/16 in both lorisoids strongly suggests that this chromosome was present in the ancestral primate genome.

Animals↗
PubMed2005

Mapping genomic rearrangements in titi monkeys by chromosome flow sorting and multidirectional in-situ hybridization.

We developed chromosome painting probes for Callicebus pallescens from flow-sorted chromosomes and used multidirectional chromosome painting to investigate the genomic rearrangements in C. cupreus and C. pallescens. Multidirectional painting provides information about chromosomal homologies at the subchromosomal level and rearrangement break points, allowing chromosomes to be used as cladistic markers. Chromosome paints of C. pallescens were hybridized to human metaphases and 43 signals were detected. Then, both human and C. pallescens probes were hybridized to the chromosomes of another titi monkey, C. cupreus. The human chromosome paints detected 45 segments in the haploid karyotype of C. cupreus. We found that all the syntenic associations proposed for the ancestral platyrrhine karyotype are present in C. cupreus and in C. pallescens. The rearrangements differentiating C. pallescens from C. cupreus re one inversion, one fission and three fusions (two tandem and one Robertsonian)that occurred on the C. cupreus lineage. Our results support the hypothesis that karyological evolution in titi monkeys has resulted in reduction in diploid number and that species with higher diploid numbers (with less derived, more ancestral karyotypes)are localized in the centre of the geographic range of the genera, while more derived species appear to occupy the periphery.

Animals↗
PubMed2005

Genetic differentiation in Scottish populations of the pine beauty moth, Panolis flammea (Lepidoptera: Noctuidae).

Pine beauty moth, Panolis flammea (Denis & Schiffermüller), is a recent but persistent pest of lodgepole pine plantations in Scotland, but exists naturally at low levels within remnants and plantations of Scots pine. To test whether separate host races occur in lodgepole and Scots pine stands and to examine colonization dynamics, allozyme, randomly amplified polymorphic DNA (RAPD) and mitochondrial variation were screened within a range of Scottish samples. RAPD analysis indicated limited long distance dispersal (FST=0.099), and significant isolation by distance (P<0.05); but that colonization between more proximate populations was often variable, from extensive to limited exchange. When compared with material from Germany, Scottish samples were found to be more diverse and significantly differentiated for all markers. For mtDNA, two highly divergent groups of haplotypes were evident, one group contained both German and Scottish samples and the other was predominantly Scottish. No genetic differentiation was evident between P. flammea populations sampled from different hosts, and no diversity bottleneck was observed in the lodgepole group. Indeed, lodgepole stands appear to have been colonized on multiple occasions from Scots pine sources and neighbouring populations on different hosts are close to panmixia.

Animals↗
PubMed2005

Reciprocal painting between humans, De Brazza's and patas monkeys reveals a major bifurcation in the Cercopithecini phylogenetic tree.

We report on reciprocal painting between humans and two Cercopithecini species, Erythrocebus patas (patas monkey) and Cercopithecus neglectus (De Brazza's monkey). Both human and monkeys chromosome-specific probes were made by degenerate oligonucleotide primed PCR (DOP-PCR) from flow sorted chromosomes. Metaphases of both monkey species were first hybridized with human chromosome-specific probes and then human metaphases were hybridized with chromosome paints from each monkey species. The human paint probes detected 34 homologous segments on the C. neglectus karyotype, while the C. neglectus probes, including the Y, revealed 41 homologous segments on the human karyotype. The probes specific for human chromosomes detected 29 homologous segments in the E. patas karyotype, while the patas monkey probes painted 34 segments on the human karyotype. We tested various hypotheses of Cercopithecini phylogeny and taxonomy developed by morphologists, molecular biologists and cytogeneticists. Our hybridization data confirm that fissions (both Robertsonian and non-Robertsonian) are the main mechanism driving the evolutionary trend in Cercopithecini toward higher diploid numbers and strongly suggest an early phylogenetic bifurcation in Cercopithecini. One branch leads to Cercopithecus neglectus/Cercopithecus wolfi while the other line leads to Erythrocebus patas/Chlorocebus aethiops. Allenopithecus nigroviridis may have diverged prior to this major phylogenetic node.

Animals↗
PubMed2004

Multi-directional chromosome painting maps homologies between species belonging to three genera of New World monkeys and humans.

We mapped chromosomal homologies in two species of Chiropotes (Pitheciini, Saki Monkeys) and one species of Aotus (Aotinae, Owl Monkey) by multi-directional chromosome painting. Human chromosome probes were hybridized to Chiropotes utahicki, C. israelita and Aotus nancymae metaphases. Wooly Monkey chromosome paints were also hybridized to Owl Monkey metaphases. We established Owl Monkey chromosome paint probes by flow sorting and reciprocally hybridized them to human chromosomes. The karyotypes of the Bearded Saki Monkeys studied here are close to the hypothesized ancestral platyrrhine karytoype, while that of the Owl Monkey appears to be highly derived. The A. nancymae karyotype is highly shuffled and only three human syntenic groups were found conserved coexisting with 17 derived human homologous associations. A minimum of 14 fissions and 13 fusions would be required to derive the A. nancymae karyotype from that of the ancestral New World primate karyotype. An inversion between homologs to segments of human 10 and 16 suggests a link between Callicebus and Chiropotes, while the syntenic association of 10/11 found in Aotus and Callicebus suggests a link between these two genera. Future molecular cytogenetic work will be needed to determine whether these rearrangements represent synapomorphic chromosomal traits.

Animals↗
PubMed2002

Tetracycline rapidly reaches all the constituent cells of uropathogenic Escherichia coli biofilms.

We have developed a method for visualizing Escherichia coli cells that are exposed to tetracycline in a biofilm, based on a previous report that liposomes containing the E. coli TetR(B) protein fluoresce when exposed to this antibiotic. By our method, cells devoid of TetR(B) also exhibited tetracycline-dependent fluorescence. At 50 microg of tetracycline ml(-1), planktonic cells of a uropathogenic E. coli (UPEC) strain developed maximal fluorescence after 7.5 to 10 min of exposure. A similar behavior was exhibited by cells in a 24- or 48-h UPEC biofilm, as examined by confocal laser microscopy, regardless of whether they lined empty spaces or occupied densely packed regions. Further, a comparison of phase-contrast and fluorescent images of corresponding biofilm zones showed that all the cells fluoresced. Thus, all the biofilm cells were exposed to tetracycline and there were no pockets within the biofilm where the antibiotic failed to reach. It also appeared unlikely that niches of reduced exposure to the antibiotic existed within the biofilms.

Anti-Bacterial Agents↗
PubMed2001

Rotational atherectomy (stentablation) in a lesion with stent underexpansion due to heavily calcified plaque.

We report treatment of a lesion with coronary stent underexpansion due to heavily calcified plaque. Conventional balloon angioplasty was attempted for in-stent restenosis, but the lesion was undilatable despite 25-atm inflation pressure. Intravascular ultrasound (IVUS) revealed stent underexpansion due to heavily calcified plaque. Rotational atherectomy was performed using a stepped burr approach, after which repeat IVUS revealed marked ablation of the stent-calcium complex. Adjunctive balloon angioplasty then easily resulted in full balloon and stent expansion, with an excellent angiographic and IVUS result. The patient's hospital course was uneventful.

Aged↗
PubMed2001

Differential success in northwards range expansion between ecotypes of the marble gallwasp Andricus kollari: a tale of two lifecycles.

The Marble gallwasp Andricus kollari has a native range divided into two geographically separated lifecycles. In Eastern Europe and Turkey, the lifecycle involves a sexual generation on Turkey oak, Quercus cerris, while in Iberia and North Africa the sexual generation host is cork oak, Q. suber. Over the last 500 years, A. kollari has expanded its range into northern Europe, following human planting of Q. cerris from Italy and the Balkans. We ask: (i) what is the genetic relationship between eastern and western distributions of Andricus kollari? Can we determine which lifecycle is ancestral, and how long ago they diverged? (ii) To what extent have eastern and western native ranges contributed to northwards range expansion? (iii) Is there any evidence for hybridization between the two life cycle types? We present analyses of allozyme data for 13 polymorphic loci and of sequence variation for a 433 bp fragment of the mitochondrial cytochrome b gene. These show: (i) that four haplotype lineages (one in Spain, two in Hungary/Italy and one in Turkey) diverged more or less simultaneously between 1 and 2 million years ago, suggesting the existence of at least four refuges through recent ice age cycles. Our data cannot resolve which lifecycle type is ancestral. (ii) Populations north of putative refuges are divided into two sets. Populations in south-west France are allied to Spain, while all remaining populations in northern Europe have been colonized from Italy and the Balkans. (iii) The transition from one race to another in south-west France is marked by abrupt transitions in the frequency of refuge-specific private alleles and corresponds closely to the northern limit of the distribution of cork oak. Although hybrids were detected in north-west France, none were detected where the two lifecycles meet in south-western France. The biology of oak gallwasps predicts that any hybrid zone will be narrow, and limited to regions where Q. cerris and Q. suber meet. Our data suggest that eastern and western A. kollari are effectively separate species.

Alleles↗
PubMed2001

Father postdivorce well-being: an exploratory model.

The purpose of this study was to test a theoretical model of the psychological well-being of fathers following divorce. The theory postulated that father postdivorce well-being was related to father role clarity, role satisfaction, age, income, education level, custody arrangement, encouragement from others, time since divorce, and involvement in an intimate relationship following divorce. Participants were 94 fathers from a midwestern city who completed self-administered questionnaires. Data were assessed using path analytic techniques. Involvement in an intimate relationship was found to have the greatest influence on father postdivorce well-being. Role satisfaction had direct effects on father postdivorce well-being and was important as a mediating variable for 4 constructs within the model. The findings suggest that father well-being following divorce is a complex phenomenon, influenced by all of the model variables except income, education level, and time since divorce. Implications for preventive intervention strategies, based on risk factors identified in this study, and suggestions for further research are discussed.

Adult↗
PubMed2000

Nasal colonization by methicillin-resistant coagulase-negative staphylococcus in community skilled nursing facility patients.

BACKGROUND: Methicillin-resistant coagulase-negative staphylococci (MRCNS) are increasing nosocomial pathogens in acute care hospital patients. However, there is little information on the epidemiology of MRCNS in skilled nursing facilities (SNFs). We report a pilot survey of the prevalence of MRCNS colonization in SNF patients. METHODS: Anterior nasal swabs were plated on oxacillin salt screening agar for selection of MRCNS. Suspected MRCNS were confirmed by coagulase and catalase tests and standard disc-diffusion antimicrobial susceptibility tests. RESULTS: The overall prevalence of MRCNS was 40% for in-house continuing SNF patients, 49% for newly admitted patients, and 60% for SNF nursing personnel. The prevalence was 13% in a "control" group of nonmedical personnel. Forty-six percent of MRCNS were resistant to ciprofloxacin. The frequency of colonization with MRCNS increased over time. After an average 17 months of facility stay, 32% of noncarriers acquired MRCNS. High frequency of colonization was associated with greater disability. CONCLUSION: Colonization with MRCNS is common among SNF patients, who can serve as a reservoir for transfer of such strains to acute care hospitals. Careful infection control practice, including judicious use of antibiotics with frequent handwashing, will remain critical policies for limiting spread of such strains.

Carrier State↗
PubMed2000

A comparative analysis of primary stenting and optimal balloon coronary angioplasty in acute myocardial infarction. Six month results from the STENT PAMI trial.

OBJECTIVE: To compare the outcome of balloon PTCA with final coronary stenosis diameter (SD) < or =30 %, with elective coronary stenting. METHODS: We performed a comparative analysis of the 6 month outcomes in patients treated with primary stenting and those who obtained an optimal balloon PTCA result treated during the first 12 hours of AMI onset included in the STENT PAMI randomized trial. RESULTS: The results were analysed into 3 groups: primary stenting (441 patients, SD=22+/-6 %), optimal PTCA (245 patients), and non-optimal PTCA (182 patients, SD= 37+/-5 %). At the end of the 6 months primary stent group presented with the lowest restenosis(23 vs. 31 vs. 45 %, p=0.001, respectively). Ischemia-driven target vessel revascularization rate (TVR) (7 vs. 15.5 vs. 19 %, p=0.001, respectively). CONCLUSION: At the 6 month follow-up, primary stenting offered the lowest restenosis and ischemia-driven TVR rates. Compared to optimal balloon PTCA. Non-optimal primary balloon PTCA pts (SD=31-50 %), had the worst late angiographic outcomes and should be treated more actively with coronary stent implantation.

Angioplasty, Balloon, Coronary↗
PubMed1999

Novel PRNP sequence variant associated with familial encephalopathy.

Human transmissible spongiform encephalopathies (TSEs) are a group of chronic progressive neurodegenerative disorders that may be hereditary, infectious, or sporadic. Hereditary TSEs are associated with mutations in the PRNP gene on chromosome 20p12-pter. We report on a family in which seven patients developed limb and truncal ataxia, dysarthria, myoclonic jerks, and cognitive decline. The age of onset in the 30s, 40s, or 50s, prolonged disease duration, cerebellar atrophy on imaging, and the presence of synchronic periodic discharges on electroencephalogram suggested a familial encephalopathy resembling Gerstmann-Sträussler-Scheinker disease. A novel H187R mutation has been identified in affected, but not in unaffected, family members or unrelated controls suggesting a pathogenic role for this mutation. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 88:653-656, 1999. Published 1999 Wiley-Liss, Inc.

Adult↗
PubMed1999

Telephone follow-up of relatives after sudden death: a survey of relatives' views.

The report of the Working Group on Bereavement Care in A&E departments recommended both the provision of follow-up for relatives and the audit of bereavement care as examples of good practice. In our adult A&E department follow-up contact is made by support workers, who have often been involved with the family at the time of death, making telephone contact four to five days later. This paper describes the role of the support workers and the results of a questionnaire sent to relatives to seek their views on this telephone follow up. In a six-month period 98 families had relatives who died in A&E; 38 (39%) of them returned completed questionnaires. The telephone call was thought to be helpful by 37 (97%) of the respondents. The commonest reasons given were: 'It showed you cared' (95%) and 'It enabled me to ask questions' (46%). We have found that the experience and, more importantly, availability of the support workers allows a level of consistency and continuity in follow-up care which can otherwise be difficult to achieve.

Attitude to Health↗
PubMed1998

Induction of estradiol-2-hydroxylase and ethoxyresorufin-O-deethylase by 3-substituted indole compounds.

Estrogen can be hydroxylated at both 2- and 16alpha-positions. These two reactions are mutually exclusive. The 2-hydroxylated estrogen is relatively inactive compared with the 16alpha-derivative; hence, one approach in anti-estrogenic therapy is to look for drugs that can induce the 2-hydroxylation pathway. In the present study, using Balb/c and C57B/6 mice as the animal models, the induction effect of several isoprenyl compounds on estradiol-2-hydroxylase and ethoxyresorufin-O-deethylase activities was studied. The compounds examined included 2'- and 3'-methylbutadienyl-indoles and their respective acid condensation products, isopropyl indolocarbazole and yuehchukene; positional isomers of indole carbinols and carboxyaldehydes, as well as 3-methylcholanthrene, the prototype inducer of cytochrome P450 1A1. Our results demonstrated that while all of them were capable of inducing cytochrome P450 1A1-mediated ethoxyresorufin-O-deethylase activity, only the 3' isomers could induce estradiol-2-hydroxylase activity. The induction of these two activities did not show any direct correlation, suggesting that cytochrome P450 1A1 was not the same enzyme catalyzing both ethoxyresorufin-O-deethylation and estradiol-2-hydroxylation. Nevertheless, both inductions were mediated by the aryl hydrocarbon receptor. Among the compounds tested, yuehchukene showed competitive binding to estrogen receptor. This, together with the induction of estradiol-2-hydroxylase activity, may account for the anti-estrogenic effect of yuehchukene.

Alkaloids↗
PubMed1998

Safety and cost-effectiveness of early discharge after primary angioplasty in low risk patients with acute myocardial infarction. PAMI-II Investigators. Primary Angioplasty in Myocardial Infarction.

OBJECTIVES: The second Primary Angioplasty in Myocardial Infarction (PAMI-II) study evaluated the hypothesis that primary percutaneous transluminal coronary angioplasty (PTCA), with subsequent discharge from the hospital 3 days later, is safe and cost-effective in low risk patients. BACKGROUND: In low risk patients with myocardial infarction (MI), few data exist regarding the need for intensive care and noninvasive testing or the appropriate length of hospital stay. METHODS: Patients with acute MI underwent emergency catheterization with primary PTCA when appropriate. Low risk patients (age <70 years, left ventricular ejection fraction >45%, one- or two-vessel disease, successful PTCA, no persistent arrhythmias) were randomized to receive accelerated care (admission to a nonintensive care unit and day 3 hospital discharge without noninvasive testing [n = 237] or traditional care [n = 234]). RESULTS: Patients who received accelerated care had similar in-hospital outcomes but were discharged 3 days earlier (4.2+/-2.3 vs. 7.1+/-4.7 days, p = 0.0001) and had lower hospital costs ($9,658+/-5,287 vs. $11,604+/-6,125 p = 0.002) than the patients who received traditional care. At 6 months, accelerated and traditional care groups had a similar rate of mortality (0.8% vs. 0.4%, p = 1.00), unstable ischemia (10.1% vs. 12.0%, p = 0.52), reinfarction (0.8% vs. 0.4%, p = 1.00), stroke (0.4% vs. 2.6%, p = 0.07), congestive heart failure (4.6% vs. 4.3%, p = 0.85) or their combined occurrence (15.2% vs. 17.5%, p = 0.49). The study was designed to detect a 10% difference in event rates; at 6 months, only a 2.3% difference was measured between groups, indicating an actual power of 0.19. CONCLUSIONS: Early identification of low risk patients with MI allowed safe omission of the intensive care phase and noninvasive testing, and a day 3 hospital discharge strategy, resulting in substantial cost savings.

Aged↗
PubMed1998

Nonresidential father involvement: a test of a mid-range theory.

This study tested a theoretical model of postdivorce involvement of nonresidential fathers with their children. The hypotheses were (a) that postdivorce father involvement is related to father parenting role identity, role clarity, child relationship quality, and father role hierarchy ranking; and (b) that several variables serve as moderators for the relationship between father parenting role identity and father involvement. Data were collected via self-report questionnaires administered to 101 fathers. Path analytic techniques were used to assess the theoretical model. Findings supported the hypotheses related to the core constructs within the theory, but not for the moderator variables within the study. Role clarity and child relationship quality were found to have both direct and indirect effects on father involvement. Father parenting role identity had a direct effect on father involvement but also functioned as a meditating variable for constructs within the model. Significant paths were found for two variables, joint custody and satisfaction with the legal system. Father postdivorce involvement is a complex phenomenon, and forces external to fathers can contribute to levels of postdivorce involvement (e.g., legal system issues).

Adult↗