496 research outputs found

    Complications and treatment errors in implant positioning in the aesthetic zone: Diagnosis and possible solutions.

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    Incorrect implant positioning can lead to functional and aesthetic compromise. Implant positioning errors can occur in three dimensions: mesiodistal, corono-apical, and orofacial. Treatment solutions to manage adverse outcomes through positioning errors require an understanding of the underlying conditions and of those factors that may have led to the error being committed in the first place. These types of complications usually occur because of human factors. If errors do occur with adverse aesthetic outcomes, they are difficult and sometimes impossible to correct. Connective tissue grafts to reverse recession defects are only feasible in defined situations. The option to remove and replace the implant may be the only recourse, provided the removal process does not further compromise the site. Error in judgment by the clinician

    The Experiences of Counselors-in-Training in a School-based Counseling Practicum

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    Counselor education programs often must choose between providing in vivo faculty supervision or a community-based setting. Programs that combine both elements have shown positive preliminary findings related to counselor development; however, the in-depth experiences of students in such programs have not been explored. This phenomenological study examined the lived experiences of counselors-in-training who participated in a school-based counseling practicum with in vivo faculty supervision. Researchers identified six themes, including continuum of support within relationships, operational challenges and concerns, needs and challenges of the community, working with children, expectations and realities, and counselor identity development. Implications for counselor education and research are provided

    The Experiences of Counselors-in-Training in a School-based Counseling Practicum

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    Counselor education programs often must choose between providing in vivo faculty supervision or a community-based setting. Programs that combine both elements have shown positive preliminary findings related to counselor development; however, the in-depth experiences of students in such programs have not been explored. This phenomenological study examined the lived experiences of counselors-in-training who participated in a school-based counseling practicum with in vivo faculty supervision. Researchers identified six themes, including continuum of support within relationships, operational challenges and concerns, needs and challenges of the community, working with children, expectations and realities, and counselor identity development. Implications for counselor education and research are provided

    Low Pathogenic Avian Influenza Isolates from Wild Birds Replicate and Transmit via Contact in Ferrets without Prior Adaptation

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    Direct transmission of avian influenza viruses to mammals has become an increasingly investigated topic during the past decade; however, isolates that have been primarily investigated are typically ones originating from human or poultry outbreaks. Currently there is minimal comparative information on the behavior of the innumerable viruses that exist in the natural wild bird host. We have previously demonstrated the capacity of numerous North American avian influenza viruses isolated from wild birds to infect and induce lesions in the respiratory tract of mice. In this study, two isolates from shorebirds that were previously examined in mice (H1N9 and H6N1 subtypes) are further examined through experimental inoculations in the ferret with analysis of viral shedding, histopathology, and antigen localization via immunohistochemistry to elucidate pathogenicity and transmission of these viruses. Using sequence analysis and glycan binding analysis, we show that these avian viruses have the typical avian influenza binding pattern, with affinity for cell glycoproteins/glycolipids having terminal sialic acid (SA) residues with α 2,3 linkage [Neu5Ac(α2,3)Gal]. Despite the lack of α2,6 linked SA binding, these AIVs productively infected both the upper and lower respiratory tract of ferrets, resulting in nasal viral shedding and pulmonary lesions with minimal morbidity. Moreover, we show that one of the viruses is able to transmit to ferrets via direct contact, despite its binding affinity for α 2,3 linked SA residues. These results demonstrate that avian influenza viruses, which are endemic in aquatic birds, can potentially infect humans and other mammals without adaptation. Finally this work highlights the need for additional study of the wild bird subset of influenza viruses in regard to surveillance, transmission, and potential for reassortment, as they have zoonotic potential

    Zanamivir Conjugated to Poly-L-Glutamine is Much More Active Against Influenza Viruses in Mice and Ferrets Than the Drug Itself

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    Purpose: Previously, polymer-attached zanamivir had been found to inhibit influenza A viruses in vitro far better than did small-molecule zanamivir (1) itself. The aim of this study was to identify in vitro—using the plaque reduction assay—a highly potent 1-polymer conjugate, and subsequently test its antiviral efficacy in vivo. Methods: By examining the structure-activity relationship of 1-polymer conjugates in the plaque assay, we have determined that the most potent inhibitor against several representative influenza virus strains has a neutral high-molecular-weight backbone and a short alkyl linker. We have examined this optimal polymeric inhibitor for efficacy and immunogenicity in the mouse and ferret models of infection. Results: 1 attached to poly-L-glutamine is an effective therapeutic for established influenza infection in ferrets, reducing viral titers up to 30-fold for 6 days. There is also up to a 190-fold reduction in viral load when the drug is used as a combined prophylactic/therapeutic in mice. Additionally, we see no evidence that the drug conjugate stimulates an immune response in mice upon repeat administration. Conclusions: 1 attached to a neutral high-molecular-weight backbone through a short alkyl linker drastically reduced both in vitro and in vivo titers compared to those observed with 1 itself. Thus, further development of this polymeric zanamivir for the mitigation of influenza infection seems warranted.National Institutes of Health (U.S.) (Grant U01-AI074443

    Deposition of fluoride on enamel surfaces released from varnishes is limited to vicinity of fluoridation site

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    The aim of the in-situ study was to determine fluoride uptake in non-fluoridated, demineralized enamel after application of fluoride varnishes on enamel samples located at various distances from the non-fluoridated samples. All enamel samples used were demineralized with acidic hydroxyethylcellulose before the experiment. Intra-oral appliances were worn by ten volunteers in three series: (1, Mirafluorid, 0.15% F; 2, Duraphat, 2.3% F and 3, unfluoridated controls) of 6 days each. Each two enamel samples were prepared from 30 bovine incisors. One sample was used for the determination of baseline fluoride content (BFC); the other was treated according to the respective series and fixed in the intra-oral appliance for 6 days. Additionally, from 120 incisors, each four enamel samples were prepared (one for BFC). Three samples (a–c) were placed into each appliance at different sites: (a) directly neighboured to the fluoridated specimen (=next), (b) at 1-cm distance (=1 cm) and (c) in the opposite buccal aspect of the appliance (=opposite). At these sites, new unfluoridated samples were placed at days 1, 3 and 5, which were left in place for 1 day. The volunteers brushed their teeth and the samples with fluoridated toothpaste twice per day. Both the KOH-soluble and structurally bound fluoride were determined in all samples to determine fluoride uptake and were statistically analyzed. One day, after fluoridation with Duraphat, KOH-soluble fluoride uptake in specimen a (=next) was significantly higher compared to the corresponding samples of both the control and Mirafluorid series, which in turn were not significantly different from each other. At all other sites and time points, fluoride uptake in the enamel samples were not different from controls for both fluoride varnishes. Within the first day after application, intra-oral-fluoride release from the tested fluoride varnish Duraphat leads to KOH-soluble fluoride uptake only in enamel samples located in close vicinity to the fluoridation site

    Autism as a disorder of neural information processing: directions for research and targets for therapy

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    The broad variation in phenotypes and severities within autism spectrum disorders suggests the involvement of multiple predisposing factors, interacting in complex ways with normal developmental courses and gradients. Identification of these factors, and the common developmental path into which theyfeed, is hampered bythe large degrees of convergence from causal factors to altered brain development, and divergence from abnormal brain development into altered cognition and behaviour. Genetic, neurochemical, neuroimaging and behavioural findings on autism, as well as studies of normal development and of genetic syndromes that share symptoms with autism, offer hypotheses as to the nature of causal factors and their possible effects on the structure and dynamics of neural systems. Such alterations in neural properties may in turn perturb activity-dependent development, giving rise to a complex behavioural syndrome many steps removed from the root causes. Animal models based on genetic, neurochemical, neurophysiological, and behavioural manipulations offer the possibility of exploring these developmental processes in detail, as do human studies addressing endophenotypes beyond the diagnosis itself

    Host genetics determine susceptibility to avian influenza infection and transmission dynamics

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    Host-genetic control of influenza virus infection has been the object of little attention. In this study we determined that two inbred lines of chicken differing in their genetic background, Lines 0 and C-B12, were respectively relatively resistant and susceptible to infection with the low pathogenicity influenza virus A/Turkey/England/647/77 as defined by substantial differences in viral shedding trajectories. Resistant birds, although infected, were unable to transmit virus to contact birds, as ultimately only the presence of a sustained cloacal shedding (and not oropharyngeal shedding) was critical for transmission. Restriction of within-bird transmission of virus occurred in the resistant line, with intra-nares or cloacal infection resulting in only local shedding and failing to transmit fully through the gastro-intestinal-pulmonary tract. Resistance to infection was independent of adaptive immune responses, including the expansion of specific IFNγ secreting cells or production of influenza-specific antibody. Genetic resistance to a novel H9N2 virus was less robust, though significant differences between host genotypes were still clearly evident. The existence of host-genetic determination of the outcome of influenza infection offers tools for the further dissection of this regulation and also for understanding the mechanisms of influenza transmission within and between birds
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