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At least 775 records · Page 43Linked to original sources
PubMed2005

Usefulness of D-optimal designs and multicriteria optimization in laborious analytical procedures. Application to the extraction of quinolones from eggs.

An analytical method has been developed to extract ciprofloxacin and enrofloxacin from eggs. The aim of this work is to determine the experimental conditions of extraction providing high recoveries with small standard deviations. An experimental design based on the D-optimality criterion and replicated three times was built to evaluate the effect of five factors related to the extraction which is the most inaccurate stage of the procedure. This non-classical design is needed because there are several practical constraints: (i) the extraction procedure is time-consuming, quinolones are not stable and the design must be performed in a single working session. (ii) The tube capacity of the centrifuge is 6, so the number of experiments will be 6 or a multiple of 6. In the optimal experimental conditions, the extraction is performed once with 5 ml of methanol. Then, fatty acids are removed with a mixture of hexane/ether. Analytes are finally separated and detected by HPLC-fluorescence without the additional step of purification by solid-phase extraction (SPE). Under these conditions, the mean recovery is 64% and 70% and the standard deviation 5% and 4% for ciprofloxacin and enrofloxacin, respectively. The capability of decision, CCalpha, is 3.1 and 2.8 microg kg(-1) of ciprofloxacin and enrofloxacin, respectively. The capability of detection, CCbeta, is 7.8 and 7.0 microg kg(-1) of ciprofloxacin and enrofloxacin, respectively. In both cases the probabilities of false positive, alpha, and of false negative, beta, were fixed at 0.05.

Algorithms↗
PubMed2025

Circulating miRNAs and inflammatory markers - Associations between miRNAs and cytokine levels point to miRNA-mediated sCD40L release from platelets.

MicroRNAs (miRNAs) are gaining increasing attention, particularly because of their involvement in immune-related signaling pathways. We investigated the association between 179 plasma-circulating miRNAs (Plasma Focus microRNA PCR Panel) and 47 cytokines ("MILLIPLEX® panel) in 692 participants of the population-based SHIP-TREND cohort (age range 21-79) and two additional cohorts to present a comprehensive map of miRNA-cytokine relations. Multivariate linear regression models identified Bonferroni-corrected significant associations between miRNAs and cytokines for EGF (pro-epidermal growth factor), PDGF-AA, PDGF-AB/BB (platelet-derived growth factor subunit A and B), VEGF-A (vascular endothelia growth factor A), and sCD40L (soluble CD40 ligand) with sCD40L showing the most robust pattern. These models were adjusted for age, sex, platelet count, BMI, smoking, and technical parameters. In the follow-up sample (N = 191, 7 years after initial sampling), we confirmed that the observed associations were stable over time and replicated our findings in an independent clinical cohort (N = 74). Furthermore, the causal mediation results provide evidence for the involvement of platelet activity in the regulation of sCD40L mediated by five miRNAs in the range of 25 %-69 % of the effect being mediated (strongest mediation for hsa-miR-223-3p). Our study highlights a strong and stable miRNA-mediated modulation of sCD40L, at the stage of platelet activation with potential subsequent effects on the interaction of immune cells and haemostasis pointing to a complex regulatory mechanism. Future research is needed to determine the clinical relevance of our observations in the context of vascular thrombosis, immunological disorders, and neurodegeneration.

Humans↗
PubMed2006

Evaluation of the marginal fit of three margin designs of resin composite crowns using CAD/CAM.

OBJECTIVES: To examine the marginal fit of resin composite crowns manufactured with the CEREC 3 system employing three different margin designs; bevel, chamfer and shoulder, by means of a replica technique and a luting agent. METHODS: Three master casts were fabricated from an impression of a typodont molar tooth and a full-coverage crown prepared with a marginal finish of a bevel, a chamfer and a shoulder. Each cast was replicated 10 times (n=10). Scanning of the replicas and crown designing was performed using the CEREC Scan system. The crowns were milled from Paradigm MZ100 composite resin blocks. The marginal fit of the crowns was evaluated with a replica technique (Aquasil LV, Dentsply), and with a resin composite cement (RelyX Unicem, Aplicap) and measured with a travelling microscope. Statistical analysis was performed using two-way ANOVA. RESULTS: For the replica technique the average marginal gaps recorded were: Bevel Group 105+/-34 microm, Chamfer Group 94+/-27 microm and Shoulder Group 91+/-22 microm. For the resin composite cement the average marginal gaps were: Bevel Group 102+/-28 microm, Chamfer Group 91+/-11 microm and Shoulder Group 77+/-8 microm. Two-way ANOVA analysis showed that there was no statistically significant difference between the three groups of finishing lines regardless of the cementation technique used. CONCLUSIONS: The marginal gap of resin composite crowns manufactured with the CEREC 3 system is within the range of clinical acceptance, regardless of the finishing line prepared or the cementation technique used.

Acrylic Resins↗
PubMed2006

Phenotype in X chromosome rearrangements: pitfalls of X inactivation study.

OBJECTIVE: X inactivation pattern in X chromosome rearrangements usually favor the less unbalanced cells. It is correlated to a normal phenotype, small size or infertility. We studied the correlation between phenotype and X inactivation ratio in patients with X structural anomalies. PATIENTS AND METHODS: During the 1999-2005 period, 12 X chromosome rearrangements, including three prenatal cases, were diagnosed in the Laboratoire de Cytogénétique of Strasbourg. In seven cases, X inactivation ratio could be assessed by late replication or methylation assay. RESULTS: In three of seven cases (del Xp, dup Xp, t(X;A)), X inactivation ratio and phenotype were consistent. The four other cases showed discrepancies between phenotype and X inactivation pattern: mental retardation and dysmorphism in a case of balanced X-autosome translocation, schizophrenia and autism in two cases of XX maleness and MLS syndrome (microphthalmia with linear skin defects) in a case of Xp(21.3-pter) deletion. CONCLUSION: Discrepancies between X inactivation ratio and phenotype are not rare and can be due to gene disruption, position effect, complex microrearrangements, variable pattern of X inactivation in different tissues or fortuitous association. In this context, the prognostic value of X inactivation study in prenatal diagnosis will be discussed.

Abnormalities, Multiple↗
PubMed2006

Social-defeat stress suppresses scent-marking and social-approach behaviors in male Mongolian gerbils (Meriones unguiculatus).

In many species, social-defeat stress induces behavioral changes in subordinate individuals. The present study examined how social-defeat stress affected scent-marking and approach behaviors in male Mongolian gerbils and whether socially defeated males selectively avoided dominant males. In Experiment 1, each of 11 gerbils was defeated by a dominant gerbil during a short social confrontation (10 min in total). For Experiment 2, the same animals were used two weeks after the end of Experiment 1. Each subject was again similarly defeated, but the two gerbils were then kept in the same cage, separated by a wire mesh for 24 h. Behavioral changes in socially defeated males were observed after social defeat; both experiments were replicated three times. After acute social defeat in Experiment 1, male gerbils did not change their scent-marking activity and frequently approached the dominant males. In contrast, males decreased scent-marking activity and approach behavior toward dominant males in Experiment 2. The amount of time defeated males approached unfamiliar males was also reduced, suggesting that social-defeat stress reduces scent-marking motivation and conspecific approach behavior rather than inducing social avoidance toward a specific individual. These findings showed that the severity of social-defeat stress is an important factor in subsequent behavioral changes in male Mongolian gerbils.

Animals↗
PubMed2006

Histopathogenesis of experimental Mycobacterium bovis infection in mice.

In-bred strains of mice are commonly used to model pathogenic infections due to their cost and utility. In order to understand better the nature of experimental tuberculosis in mice, we infected BALB/c mice with a virulent field isolate of Mycobacterium bovis. Mice were sacrificed at intervals in order to visualise the pathological lesions in major internal organs. Pathological lesions in tissues increased in number and severity over time and replicated many of the salient features observed in badgers and cattle infected with M. bovis. These similarities are discussed. Examination of pathological lesions at terminal stages of infection enabled us to suggest the lethal effects of M. bovis mediated through the host response. We conclude that the mouse is a relevant surrogate species in which to study the virulence of M. bovis, as well as the influence of vaccination on its pathogenicity.

Animals↗
PubMed2004

Exposure to ozone enhances antigen-presenting activity concentration dependently in rats.

The effect of ozone (O(3)) on the symptoms of allergic asthma and the mechanisms underlying have not yet been fully elucidated. Antigen presentation is one of the factors contributing to the allergic reaction. Therefore, we investigated the effects of repeated exposure to O(3) on antigen-presenting (AP) activity, on the expression of cell-surface molecules associated with antigen presentation (Ia, B7.1, B7.2 and CD11b/c) in bronchoalveolar lavage cells (BAL cells), and on allergic asthma-like symptoms. Rats were exposed to 0.3, 0.56, 1ppm O(3) or filtered air for a 3-day period every 2 weeks, this was replicated three times. AP activity was assessed by measuring antigen-specific T-cell proliferation; and the expression of cell-surface molecules, by flow cytometry. Rats were also made to inhale aerosolized 1% ovalbumin (OVA) or saline for 10min post-exposure to O(3), and allergic asthma-like symptoms were measured by determining the increase in enhanced pause (Penh), which correlates well with lung resistance. O(3) increased both AP activity and expression of Ia and costimulatory molecules in BAL cells concentration dependently. It also increased lung resistance, and the increase in lung resistance after O(3) exposure was significantly higher in the OVA-inhaled group than in the saline-inhaled group. The present results show that O(3) increased AP activity concentration dependently and suggest that O(3) might aggravate allergy symptoms by enhancing AP activity.

Administration, Inhalation↗
PubMed2006

Bridging mandibular continuity defects with miniplates: an experimental study.

Various miniplate fixation techniques were studied in dogs to determine whether the use of miniplate fixation provides sufficient stability in mandibular continuity defects. Continuity resections measuring 15 mm were made on the mandibles of 16 dogs and were bridged using 4 miniplate fixation techniques, each replicated 4 times. All dogs were placed on a normal diet throughout the postoperative period. Clinical and radiological examinations were carried out 6 weeks later. We found that the group with both double miniplates and bicortical screws was stable, whereas the groups utilizing either a single miniplate or monocortical screws were not. The results of this study indicate that using a combination of double miniplates and bicortical screws to bridge defects after mandibular resection produces stable and predictable results.

Animals↗
PubMed2006

The effect of mixed or sequential grazing of cattle and sheep on the faecal egg counts and growth rates of weaned lambs when treated with anthelmintics.

An experiment was conducted over two successive years (2002 and 2003) to investigate the effects of grazing improved permanent pasture (mainly perennial ryegrass/white clover) by cattle or sheep, either sequentially or mixed, on the faecal egg counts and growth rates of weaned lambs when treated with anthelmintics. The grazing season was divided into two parts, May-July then July-October, relating to the pre- and post-weaning of the lambs. Four grazing regimes, replicated three times, were compared: (1) sheep only from May to October (SS); (2) cattle May to July followed by lambs until October (C/S); (3) cattle and sheep May to July followed by lambs until October (C+S/S); and (4) cattle and sheep May to July followed by cattle and lambs until October (C+S/C+S). Sward height was maintained at 6 cm using a "put and take" stocking system. At weaning, lambs were weighed and treated with an anthelmintic (0.08% ivermectin drench, Oramec) before being allocated to plots. They were then weighed and drenched every 28 days until the end of the experiment (Day 84). Faecal egg counts (FEC) were measured in all lambs immediately prior to each anthelmintic treatment. In 2002 and 2003, there were differences between the groups in FEC, with the SS lambs having the highest values and C/S lambs the lowest (P<0.01). There were also differences in the rate of liveweight gain of the lambs in each of the study years: for this parameter SS lambs had the lowest growth rate but the fastest growth was in C+S/C+S lambs not C/S lambs (P<0.01), indicating that these differences were due to factors other than parasite infection. Overall, sequential grazing of pastures with cattle then sheep reduced the faecal egg counts in lambs regularly treated with anthelmintics when compared with lambs grazing in mixed systems with cattle and sheep or with sheep only systems, however, the highest growth rates were observed in lambs in the mixed cattle/sheep grazing system throughout.

Animal Husbandry↗
PubMed2003

Coxsackievirus-mediated hyperglycemia is enhanced by reinfection and this occurs independent of T cells.

The induction of autoimmunity by viruses has been hypothesized to occur by a number of mechanisms. Coxsackievirus B4 (CB4) induces hyperglycemia in SJL mice resembling diabetes in humans. While virus is effectively cleared within 2 weeks, hyperglycemia does not appear until about 8-12 weeks postinfection at a time when replicative virus is no longer detectable. In SJL mice, reinfection with CB4 enhanced the development of hyperglycemia. As predicted, the immune system responded more rapidly to the second infection and virus was cleared more swiftly. However, while infiltrating T cells were found within the pancreas, depletion of the CD4 T cell population prior to secondary infection or use of CD8 knock-out mice had no effect on the development of virus-mediated hyperglycemia. In conclusion, enhanced hyperglycemia induced by CB4 occurs independent of the T cell response.

Animals↗
PubMed2003

Anosognosia for left-sided motor and sensory deficits, motor neglect, and sensory hemiinattention: is there a relationship?

In recent years, research on unilateral spatial neglect has focused on dissociations between different aspects of the clinical syndrome, which is now considered by many students as a multi-componential disorder. Notwithstanding this leading view, there is at least one empirical argument which supports a unitary interpretation of the disorder. This is based on the observation, now replicated many times, that a variety of sensory stimulations (vestibular, optokinetic, transcutaneous mechanical vibration and nervous electrical, visual prism adaptation) involving a lateral change (left-right asymmetry) in the input pattern, affect in a very similar fashion virtually all manifestations of the syndrome, including: visuo-spatial neglect; hemianaesthesia (somatosensory hemi-inattention); extinction, hemiparesis, hemiplegia, and anosognosia for these motor disorders; somatoparaphrenia. These effects may be accounted for with reference to a spatial medium, articulated in a number of specific components, which is modulated by sensory input in a fundamentally similar fashion. Recent investigations concerning the neural bases of some of these stimulations support this view. In this chapter the case of the co-variation of the effects of vestibular stimulation on motor deficits and on anosognosia for hemiplegia is considered. The suggestion is made that one mechanism underlying anosognosia for hemiplegia is unawareness of a deficit of intention, or movement planning component, rather than, or in addition to, unawareness of a primary motor deficit. Temporary remission of anosognosia after vestibular stimulation may represent recovery from this neglect-related component, of which, as of other manifestations of the syndrome, patients are typically unaware. The recovered intention to move may allow the detection by the patient of the presence of a residual primary motor deficit, through a feedback mechanism.

Agnosia↗
PubMed1998

Quantification of bull sperm characteristics measured by computer-assisted sperm analysis (CASA) and the relationship to fertility.

Two experiments were conducted to evaluate semen quality of bulls housed under controlled conditions at a large AI facility and relate results to fertility. In Experiment 1 semen was collected from six 6-yr-old bulls twice daily at 3- to 4-d intervals for 3 d. In Experiment 2 eleven 6- to 11-yr-old bulls were used. Extensive breeding information was available and semen was collected as in Experiment 1 but replicated 4 times. Standard semen analysis and computer-assisted sperm analysis (CASA) with the Hamilton Thorne IVOS, model 10 unit, were performed on 36 first and second ejaculates in Experiment 1 and on 44 first ejaculates in Experiment 2. Sixteen fields (2 chambers with 8 fields per chamber) were examined per sample. In Experiment 1 the correlation between estimated sperm concentration by spectrophotometry and CASA was 0.91 (P < 0.01). Among bulls the range in the percentage of motile spermatozoa was 52 to 82 for CASA versus 62 to 69 for subjective measurements made by highly experienced technicians. Thus, CASA, with high repeatability, provided a more discriminating estimate of the percentage of motile sperm cells than did the subjective procedure. Bull effect was much greater than any other variable in the experiments. Chamber differences were small and so the results for the 2 chambers with 8 fields each were combined. One to five CASA values were correlated with bull fertility, defined as 59-day nonreturn rates corrected for cow and herd effects. The percentage of motile spermatozoa accounted for a small fraction of the total variation in fertility (r2 = 0.34). However higher r2 values (0.68 to 0.98) were obtained for 2 to 5 variables used in the multiple regression equations. The results are promising, and further testing will determine more precisely which of these CASA variables are most useful in estimating bull fertility potential.

Animals↗
PubMed2002

Initial interaction of rat bone marrow cells with non-coated and calcium phosphate coated titanium substrates.

Initial interactions of rat bone marrow (RBM) cells with smooth titanium, rough titanium or calcium phosphate coated substrates were tested. Cells were seeded onto the substrates, and attachment, integrin expression and spreading and morphology were studied. We found no difference in attachment of RBM cells to the different materials. We did find differences in the percentage of attached cells within a certain time between replicate runs of the experiments. RBM cells on all materials express alpha1, alpha3, alpha5, alpha6 and beta1 subunits. Again there was a large difference in expression patterns on RBM cells in different runs. No difference was found in expression on the various materials. For alpha1, alpha5, alpha6 and beta1, no difference was found in expression between attached and unattached cells. Expression of alpha3 was similar on attached and unattached cells during early culture. At the end of culture, alpha3 expression was downregulated for attached cells and not for unattached cells. This resulted in a higher expression of alpha3 for unattached cells compared to attached cells. Cells did spread on all materials, and reached a larger cell size on smooth titanium than on the rough materials. Morphology of the cells on the materials differed. On smooth titanium, cells usually showed a compact cell body with short cellular extensions. On the rough materials, cells often showed elongated shapes, with many thin cellular extensions. From this we conclude that the substrate surface characteristics of the materials we used do not influence attachment or integrin expression during the initial cell-material interactions. On the other hand, spreading behavior and cell morphology do depend on substrate surface characteristics.

Animals↗
PubMed2003

Intergeneric transfer of the Enterococcus faecalis plasmid pIP501 to Escherichia coli and Streptomyces lividans and sequence analysis of its tra region.

The nucleotide sequence of the transfer (tra) region of the multiresistance broad-host-range Inc18 plasmid pIP501 was completed. The 8629-bp DNA sequence encodes 10 open reading frames (orf), 9 of them are possibly involved in pIP501 conjugative transfer. The putative pIP501 tra gene products show highest similarity to the respective ORFs of the conjugative Enterococcus faecalis plasmids pRE25 and pAMbeta1, and the Streptococcus pyogenes plasmid pSM19035, respectively. ORF7 and ORF10 encode putative homologues of type IV secretion systems involved in transport of effector molecules from pathogens to host cells and in conjugative plasmid transfer in Gram-negative (G-) bacteria. pIP501 mobilized non-selftransmissible plasmids such as pMV158 between different E. faecalis strains and from E. faecalis to Bacillus subtilis. Evidence for the very broad-host-range of pIP501 was obtained by intergeneric conjugative transfer of pIP501 to a multicellular Gram-positive (G+) bacterium, Streptomyces lividans, and to G- Escherichia coli. We proved for the first time pIP501 replication, expression of its antibiotic resistance genes as well as functionality of the pIP501 tra genes in S. lividans and E. coli.

Base Sequence↗
PubMed1987

Zinc-induced peripheral anosmia and behavioral responses to novelty in mice: a quantitative-genetic analysis.

Adult male mice were made anosmic by intranasal flushing with a 5% zinc sulfate solution. Twelve behavioral variables were measured in treated as well as saline-irrigated control animals placed in a novel environment. The genetic underpinnings and the genotype-treatment interactions with regard to these behaviors were analyzed in a classical Mendelian cross between the inbred strains C57BL/6 and DBA/2 and in a full 4 X 4 diallel cross, replicated five times, between these strains and strains C3H/St an CPB-K. Based on the hypothesis of an evolutionary history of directional selection for a well-balanced information-processing system, one might expect directional dominance for decrease in exploration after anosmization. Although decreases were found for several behavioral phenotypes, only few and relatively unimportant genotype-treatment interactions were present. This absence of any kind of genetic variation for behavioral change after anosmization points to an extremely strong directional selection which has eliminated all less favorable alleles. The findings support the hypothesis of directional selection for an efficient olfactory information-processing system.

Animals↗
PubMed2003

Development of a rapid method using nucleic acid sequence-based amplification for the detection of astrovirus.

We have developed a rapid method to detect astrovirus in fecal specimens utilizing nucleic acid sequence-based amplification (NASBA) and several detection methodologies, including a sandwich hybridization assay based on DNA-tagged liposomes (liposome-strip detection assay). RNA was extracted from 65 stool specimens that were positive for astrovirus by enzyme immunoassay and was amplified by both NASBA and reverse transcriptase PCR (RT-PCR). Also extracted and amplified were 19 specimens containing rotavirus, 20 specimens containing norovirus, five specimens containing adenovirus, 15 water negative control specimens, and eight specimens containing astrovirus reference strains. NASBA products were detected by electrochemiluminescence detection (ECL) and by liposome-strip detection; RT-PCR products were detected by ethidium bromide staining following gel electrophoresis and by liquid hybridization assay (LHA). There was no significant difference in the detection rates of NASBA- and RT-PCR-based assays, with one exception in which the NASBA/ECL assay detected astrovirus in eight specimens that tested negative by the RT-PCR/LHA assay. These results suggest that these NASBA-based detection methods have detection rates that are as good as or better than those of RT-PCR-based methods. Both NASBA and liposome-strip detection may be useful for field studies and environmental testing because these methods are rapid and do not require specialized equipment.

Astroviridae Infections↗