Biomedical subjects

Eva Nagy

Publications and source records attributed to Eva Nagy.

12 recordsLinked to original sources

PubMed2006

Conflict between guideline methodologic quality and recommendation validity: a potential problem for practitioners.

BACKGROUND: It is not clear if good methodologic quality in current practice guidelines necessarily leads to more valid recommendations, i.e., those that are supported with consistent research evidence or, when evidence is conflicting or lacking, with sufficient consensus among the guideline development team. To help clarify this issue, we assessed whether there is a link between methodologic quality and recommendation validity in practice guidelines for the use of laboratory tests in the management of patients with non-small cell lung cancer (NSCLC). METHODS: We conducted a systematic review of data on laboratory tests in NSCLC published in English or in French within the last 10 years and retrieved 11 practice guidelines for the use of these tests. The guidelines were critically appraised and scored for methodologic quality and recommendation validity based on the Appraisal of Guidelines Research and Evaluation (AGREE) criteria and on the systematic review. RESULTS: Overall, these 11 guidelines had considerable shortcomings in methodologic quality and, to a lesser extent, in recommendation validity. Practice guidelines with the best methodologic quality were not necessarily the most valid in their recommendations, and conversely. CONCLUSIONS: Poor methodologic quality and lack of recommendation validity in laboratory medicine call for methodologic standards of guideline development and for international collaboration of guideline development agencies. We advise readers of guidelines to critically evaluate the methods used as well as the content of the recommendations before adopting them for use in practice.

Carcinoma, Non-Small-Cell Lung↗

PubMed2006

Study of vertical transmission of fowl adenoviruses.

The vertical transmission of fowl adenoviruses (FAdVs) was studied by polymerase chain reaction (PCR) and virus isolation. Liver, spleen, kidney, and bursa of Fabricius were collected from 60 chicks 1 d old representing progenies hatched to 6 broiler breeder flocks in 6 geographically different premises in Ontario, Canada. The presence of FAdV DNA sequences was detected by PCR with the use of primers specific for the conserved pVI gene of FAdV-9 in 58 (24%) of the 240 samples tested. All samples from 1 flock were negative for FAdV sequences, and only a few samples were positive in 3 flocks, whereas 32% and 72% of the samples from the other 2 flocks were positive. Testing of 1 sample with primers designed to amplify the L1 region of the hexon protein gene and amino acid sequence analysis of the PCR product indicated that the sequences were similar to serotype-8a FAdV sequences. No fowl adenoviruses were isolated in chicken hepatoma cells from any of the 30 samples inoculated. These findings imply that vertical transmission and establishment of latent infection with FAdVs can occur in chickens.

Adenoviridae Infections↗

PubMed2005

Development of a real-time PCR assay using SYBR Green chemistry for monitoring Marek's disease virus genome load in feather tips.

Feather follicles of birds infected with Marek's disease virus (MDV) serve as the sole source of infectious virus particles. The present study was aimed at developing a SYBR Green real-time PCR assay to detect and quantify MDV loads in feather tips targeting meq gene of the virus. The assay had a dynamic range of 8 logs, mean inter- and intra-assay coefficient variation (CV) of <5% and minimum detection limit of 15 MDV genome copies when plasmid DNA was used as the template. The sensitivity of the assay was compared with that of the conventional PCR technique and found to be 2.5-10 times more sensitive than the conventional PCR technique. The assay was validated using feather tip DNA preparations derived from chickens infected with 250 plaque forming units (PFU) of RB1B strain of MDV and sampled on days 7, 14, 21 and 28 post-infection (p.i.) along with uninfected chickens. MDV genome was quantifiable in feather tips of infected birds by day 7 p.i. and the number of MDV copies peaked by day 14 p.i., but then gradually decreased by day 28. This reliable real-time PCR assay may be used for monitoring MDV genome loads in tissues of experimentally or naturally infected birds.

Animals↗

PubMed2005

Quality of guidelines for the laboratory management of diabetes mellitus.

BACKGROUND: There is increasing concern about the quality and reliability of practice guidelines, especially in the field of laboratory medicine, as most recommendations are developed by clinical specialty societies, often without involving laboratory professionals. Little information is available on the methodological quality of guidelines for the use of laboratory investigations in the care of specific diseases. We describe a pilot assessment of the most well-known guidelines for the diagnosis and monitoring of diabetes mellitus (DM). METHODS: Practice guidelines on DM published in English between 1999 and 2005 April were identified by systematic searching in Medline and international guideline databases. Fifty four DM guidelines were retrieved, of which 29 met our inclusion criteria. The four most widely used international guidelines (WHO, ADA, NACB, NICE) were selected for a critical appraisal of their methodological quality. This was carried out by seven independent assessors using a validated checklist, the AGREE Instrument. Twenty three guideline attributes arranged in six independent domains were investigated and the mean scores of assessors for each attribute and the aggregated scores for each domain were calculated. Cronbach's alpha and interclass correlations were calculated to measure internal consistency and reliability within each domain. The four guidelines were compared using one-way ANOVA and ANOVA using repeated measurements. RESULTS: The selected four guidelines on DM have significant shortcomings in demonstrating and/or reporting multidisciplinary stakeholder involvement in the guideline development process, evidence-based methodology for formulating recommendations, applicability of statements, and disclosing any conflicts of interest or reporting editorial independence. CONCLUSIONS: Poor quality and lack of explicitness of recommendations in laboratory medicine call for methodological standards of guideline development and reporting, and for an international collaboration of guideline development activities, to increase the internal and external validity of recommendations in laboratory practice.

Diabetes Mellitus↗

PubMed2004

Plasma GLP-2 levels and intestinal markers in the juvenile pig during intestinal adaptation: effects of different diet regimens.

Adaptation of the residual small bowel following resection is dependent on luminal and humoral factors. We aimed to establish if circulating levels of glucagon-like peptide (GLP-2) change under different dietary regimens following resection and to determine if there is a relationship between plasma GLP-2 levels and markers of intestinal adaptation. Four-week-old piglets underwent a 75% proximal small bowel resection (n = 31) or transection (n = 14). Postoperatively they received either pig chow (n = 14), nonpolymeric (elemental) infant formula (n = 7), or polymeric infant formula alone (n = 8) or supplemented either with fiber (n = 6) or with bovine colostrum protein concentrate (CPC; n = 10) for 8 weeks until sacrifice. Plasma GLP-2 levels were measured at weeks 0, 2, 4, and 8 postoperatively. In addition, end-stage parameters were studied at week 8 including weight gain, ileal villus height, crypt depth, and disaccharidase levels. Plasma GLP-2 levels were higher in resected animals compared to transected animals fed the same diet. Plasma GLP-2 levels were significantly increased in the colostrum protein isolate-supplemented animals following resection compared to all other diet groups. The increase in plasma GLP-2 (pM) was greatest in the first 2 weeks postresection (week 0, 15.5; week 2, 30.9), followed by a plateau at weeks 2 to 4 and a decrease in GLP-2 levels from week 4 to week 8. At week 8, no relationships were found between the plasma GLP-2 levels and the measurements of weight gain, villus height, lactase, sucrase, maltase, crypt depth, or villus/crypt ratio. Plasma GLP-2 levels increase in the first weeks following massive small intestinal resection. The increase in plasma GLP-2 levels was enhanced by supplementation of the diet with CPC. The changes in GLP-2 levels observed in this study may suggest that GLP-2 plays a role in the adaptive response in the intestine following resection in this preclinical model.

Adaptation, Physiological↗

PubMed2003

Antibody response and virus tissue distribution in chickens inoculated with wild-type and recombinant fowl adenoviruses.

We demonstrated that the long tandemly repeated region (TR-2) is dispensable for in vitro replication of fowl adenovirus 9 (FAdV-9). The TR-2-deleted recombinant FAdV-9 expressing the enhanced green fluorescence protein was further characterized for in vivo effects. Groups of chickens were exposed to recombinant or wild-type FAdV-9 by intramuscular injection, through the feed or drinking water and one group served as a negative control. The antibody (Ab) response, evaluated by ELISA and a plaque reduction test depended on the virus, dosage and the route of inoculation. Although the highest levels of anti-viral Ab were detected in chickens inoculated intramuscularly (i.m.) with wild-type FAdV-9, the deletion of TR-2 did not have a significant effect on the immune response. The tissue distribution of the virus was examined by the polymerase chain reaction (PCR) and was similar for both wild-type and recombinant viruses. Based on these results the TR-2 was dispensable for viral replication in vivo and did not influence virus distribution, and the recombinant FAdV-9 induced the same immune response as the wild-type virus.

Adenoviridae Infections↗

PubMed2003

Phylogenetic analysis reveals extensive evolution of avian paramyxovirus type 1 strains of pigeons (Columba livia) and suggests multiple species transmission.

Partial sequence and residue substitution analyses of the fusion protein gene were performed for 68 strains of avian paramyxovirus type 1 of pigeons (PPMV-1), an antigenic variant of Newcastle disease virus (NDV) of chickens, derived from 16 countries between 1978 and 2002. The majority of isolates clustered into a single genetic lineage, termed VIb/1, within genotype VI of NDV strains of chickens, whereas a small number of isolates that originated in Croatia after 1995, grouped in a highly diverged lineage, termed VIb/2, indicating a separate host-switching event from that of VIb/1 strains. Four distinct subgroups of lineage VIb/1, Iraqi (IQ), early European (EU/ea), North American (NA) and recent European (EU/re) have emerged and circulated in the past decades. Subgroup EU/ea and NA strains were responsible for the main streams of infection in the 1980s, while EU/re viruses for infections in the 1990s. The degree of genetic diversity of viruses in the early phase of the epizootic suggested a prolonged infection period of the pigeon-type viruses prior to the emergence of the disease in the early 1980s. Shared derived character analysis showed a close genetic relationship to Sudanese viruses from the mid-1970, suggesting that PPMV-1 viruses could be of African origin.

Animals↗

PubMed2003

Indirect method for prediction of hemagglutination inhibition antibody titers to Newcastle disease virus in chickens by titration of antibodies in egg yolk.

Attempts were made to establish methods for indirect prediction of hemagglutination inhibition (HI) antibody titers to Newcastle disease virus (NDV) in sera of laying hens and day-old chicks by determining if these are correlated to HI titers in egg yolks. For this purpose, geometric means of HI antibody titers in sera from 60 hens, yolks from 60 matched eggs, and sera from 180 day-old chicks of an identical vaccination program were measured and plotted. There was a significant correlation between HI antibody titers in yolks (X) and hens (Y), with a linear regression of Y = 23.24 + 0.47X and a correlation coefficient of r = 0.65. The linear regression between HI antibody titers in yolks (X) and chicks (Y) was Y = 6.33 + 0.36X (r = 0.58). Immunity to NDV in hens and their offspring can be maintained effectively, and the proper time for the vaccination or booster can be determined by reference to HI titers predicted from the linear regression in the present study. The approach of testing egg yolk for HI titers provides a feasible alternative to determining HI titers from blood samples and eliminates stress in birds during blood sampling.

Animals↗

PubMed2002

Unique features of fowl adenovirus 9 gene transcription.

We examined the transcriptional organization of fowl adenovirus 9 (FAdV-9) and analyzed temporal transcription profiles of its early and late mRNAs. At least six early and six late transcriptional regions were identified for FAdV-9. Extensive splicing was observed in all FAdV-9 early transcripts examined. Sequence analysis of the cDNAs representing the early proteins identified untranslated leader sequences, precise locations of splice donor and acceptor sites, as well as polyadenylation signals and polyadenylation sites. A unique characteristic, compared to other adenoviruses, was the detection by RT-PCR of multiple transcripts specific for each of five late genes (protein III, pVII, pX, 100K, and fiber), suggesting that FAdV-9 late transcripts undergo more extensive splicing than reported for other adenoviruses.

Adenovirus Early Proteins↗

PubMed2002

Potent gene-specific inhibitory properties of mixed-backbone antisense oligonucleotides comprised of 2'-deoxy-2'-fluoro-D-arabinose and 2'-deoxyribose nucleotides.

Phosphorothioate deoxyribonucleotides (PS-DNA) are among the most widely used antisense inhibitors. PS-DNA exhibits desirable properties such as enhanced nuclease resistance, improved bioavailability, and the ability to induce RNase H mediated degradation of target RNA. Unfortunately, PS-DNA possesses a relatively low binding affinity for target RNA that impacts on its potency in antisense applications. We recently showed that phosphodiester-linked oligonucleotides comprised of 2'-deoxy-2'-fluoro-D-arabinonucleic acid (FANA) exhibit both high binding affinity for target RNA and the ability to elicit RNase H degradation of target RNA [Damha et al. (1998) J. Am. Chem. Soc. 120, 12976]. In the present study, we evaluated the antisense activity of phosphorothioate-linked FANA oligonucleotides (PS-FANA). Oligonucleotides comprised entirely of PS-FANA were somewhat less efficient in directing RNase H cleavage of target RNA as compared to their phosphorothioate-linked DNA counterparts, and showed only weak antisense inhibition of cellular target expression. However, mixed-backbone oligomers comprised of PS-FANA flanking a central core of PS-DNA were found to possess potent antisense activity, inhibiting specific cellular gene expression with EC(50) values of less than 5 nM. This inhibition was a true antisense effect, as indicated by the dose-dependent decrease in both target protein and target mRNA. Furthermore, the appearance of mRNA fragments was consistent with RNase H mediated cleavage of the mRNA target. We also compared a series of PS-[FANA-DNA-FANA] mixed-backbone oligomers of varying PS-DNA core sizes with the corresponding 2'-O-methyl oligonucleotide chimeras, i.e., PS-[2'meRNA-DNA-2'meRNA]. Both types of oligomers showed very similar binding affinities toward target RNA. However, the antisense potency of the 2'-O-methyl chimeric compounds was dramatically attenuated with decreasing DNA core size, whereas that of the 2'-fluoroarabino compounds was essentially unaffected. Indeed, a PS-FANA oligomer containing a single deoxyribonucleotide residue core retained significant antisense activity. These findings correlated exactly with the ability of the various chimeric antisense molecules to elicit RNase H degradation of the target RNA in vitro, and suggest that this mode of inhibition is likely the most important determinant for potent antisense activity.

Arabinose↗

PubMed2002

Sequence analysis of porcine adenovirus serotype 5 fibre gene: evidence for recombination.

The nucleic acid and deduced amino acid sequence of the fibre gene of the HNF-61 strain of porcine adenovirus serotype 5 (PAdV-5) was determined and compared to that of the HNF-70 strain of the same serotype (Nagy et al., J Gen Virol 82, 525-529, 2001) and also to adenovirus fibre genes from the genera Mastadenovirus and Atadenovirus. The putative HNF-61 and HNF-70 proteins were similar to each other, with 90% amino acid identity. Conserved amino acid sequences described for mastadenovirus fibre shafts were identified in the shaft regions of both PAdV-5 fibres, except for the so-called TLWT motif. The head regions of the PAdV-5 fibre did not resemble any of the known mastadenovirus fibre heads, but they showed characteristics of the fibre head protein sequences of viruses grouped in the proposed genus Atadenovirus (Benkö et al., Virus Taxonomy, Seventh Report of the International Committee on the Taxonomy of Viruses, Academic Press, New York, San Diego, 2000, pp. 227-238). The findings suggested recombination between viruses of different adenovirus genera.

Adenoviruses, Porcine↗

PubMed2002

Influence of diet complexity on intestinal adaptation following massive small bowel resection in a preclinical model.

AIMS: To investigate the effect of dietary complexity on intestinal adaptation using a preclinical model. METHODS: Four-week-old piglets underwent a 75% proximal small bowel resection or transection operation (control). Post-operatively, animals received either pig chow (n = 15), polymeric formula (n = 9), polymeric formula plus fiber (n = 6), or elemental formula (n = 7). RESULTS: The weight gain of all groups was reduced compared with controls that were fed the same diet. Animals that had a resection, which were fed elemental formula, had significantly reduced weight gain compared with the other groups (4.7 4.2 vs 30.7 7.1 kg chow and 11.5 1.3 kg polymeric formula). Villus height was increased in the jejunum, ileum and terminal ileum of resected animals compared with controls in animals fed with pig chow, polymeric formula and elemental formula. The animals that had a resection had a significant reduction in the transepithelial conductance (10.4 5.5 vs 25.4 6.5 mS/cm2) and 51Chromium-EDTA flux (2.8 1.9 vs 4.8 4.9 microL/h per cm2) compared with the controls. CONCLUSIONS: A complex diet was found to be superior to an elemental diet in terms of the morphological and functional features of adaptation following massive small bowel resection.

Adaptation, Physiological↗