Pathogen elimination and prevention within a regulated,Designated Pathogen Free,closed pig herd for long‐term breeding and production of xenotransplantation materials

Background

We established a Source Animal (barrier) Facility (SAF ) for generating designated pathogen‐free (DPF ) pigs to serve as donors of viable organs, tissues, or cells for xenotransplantation into clinical patients. This facility was populated with caesarian derived, colostrum deprived (CDCD ) piglets, from sows of conventional‐specific (or specified) pathogen‐free (SPF ) health status in six cohorts over a 10‐month period. In all cases, CDCD piglets fulfilled DPF status including negativity for porcine circovirus (PCV ), a particularly environmentally robust and difficult to inactivate virus which at the time of SAF population was epidemic in the US commercial swine production industry. Two outbreaks of PCV infection were subsequently detected during sentinel testing. The first occurred several weeks after PCV ‐negative animals were moved under quarantine from the nursery into an animal holding room. The apparent origin of PCV was newly installed stainless steel penning, which was not sufficiently degreased thereby protecting viral particles from disinfection. The second outbreak was apparently transmitted via employee activities in the Caesarian‐section suite adjacent to the barrier facility. In both cases, PCV was contained in the animal holding room where it was diagnosed making a complete facility depopulation‐repopulation unnecessary.

Method

Infectious PCV was eliminated during both outbreaks by the following: euthanizing infected animals, disposing of all removable items from the affected animal holding room, extensive cleaning with detergents and degreasing agents, sterilization of equipment and rooms with chlorine dioxide, vaporized hydrogen peroxide, and potassium peroxymonosulfate, and for the second outbreak also glutaraldehyde/quaternary ammonium. Impact on other barrier animals throughout the process was monitored by frequent PCV diagnostic testing.

Result

After close monitoring for 6 months indicating PCV absence from all rooms and animals, herd animals were removed from quarantine status.

Conclusion

Ten years after PCV clearance following the second outbreak, due to strict adherence to biosecurity protocols and based on ongoing sentinel diagnostic monitoring (currently monthly), the herd remains DPF including PCV negative.

     

Incidence of white spot lesions among patients treated with clear aligners and traditional braces

Objectives:To compare the incidence of white spot lesions (WSLs) among patients treated with aligners and those treated with traditional braces.Materials and Methods:A group of 244 aligner patients (30.4 ± 14 years) was compared to a group of 206 patients (29.2 ± 11.5 years) treated with traditional fixed braces. Consecutive cases in the late mixed or permanent dentitions who had high-quality pre- and posttreatment digital photographs available were included in the study. Each set of photographs was independently evaluated by two investigators to determine pretreatment oral hygiene (OH), fluorosis, and WSLs, as well as changes in OH and WSLs during treatment.Results:Approximately 1.2% of the aligner patients developed WSLs, compared to 26% of the traditionally treated patients. The numbers of WSLs that developed were also significantly (P < .001) less among the aligner patients. The aligner patients developed three new WSLs, while the traditionally treated patients developed 174 WSLs. The incidence of WSLs was greater for the maxillary than for the mandibular teeth, and it was greater for the canines than for the incisors. For the patients treated with traditional braces, fair or poor pretreatment OH, worsening of OH during treatment, preexisting WSLs, and longer treatment duration significantly (P < .05) increased the risk of developing WSLs during treatment.Conclusions:Patients treated with aligners have less risk of developing WSLs than do patients treated with traditional braces, which could be partially due to shorter treatment duration, or better pretreatment OH.     

Pituitary-adrenal, hormonal changes during induced hypotension with labetalol or isoflurane for middle-ear surgery

Background : Pituitary-adrenal secretion during induced hypotension for middle-ear surgery has received little attention. Previous work failed to differentiate the effects of induced hypotension from surgical stimulation. We have undertaken a preliminary study examining the effects of hypotension, achieved with labetalol or isoflurane, on pituitary-adrenal secretion before, during and after middle-ear surgery. Methods : Twenty-four patients were allocated randomly to 3 groups. The control group were anaesthetised with isoflurane, and normotension maintained for 30 min before hypotension was induced with isoflurane and surgery started. In the labetalol group, this drug was given i.v. to obtain a mean arterial pressure (MAP) of 60 mm Hg for 30 min before surgery and hypotension maintained with labetalol during the operation. In the isoflurane group, hypotension was induced to a MAP of 60 mm Hg for 30 min before surgery and continued throughout the procedure. All 3 groups received metoprolol i.v. before hypotension was established. Blood samples were collected before induction of anaesthesia, during anaesthesia alone (normotensive or hypotensive), surgery with hypotension, and recovery. They were analysed for adrencorticotropic hormone (ACTH), arginine vasopressin (AVP), cortisol and aldosterone. Results : Induced hypotension before surgery failed to stimulate release of ACTH, AVP and cortisol. No significant increase in these hormones occurred until the postoperative period. Aldosterone concentrations increased significantly during anaesthesia and hypotension in the labetalol and isoflurane groups (P <0.05) and continued to rise significantly in all 3 groups during surgery. However, there was no significant difference in aldosterone concentration before surgery between the control and the 2 hypotensive groups. Conclusion : ACTH, AVP and cortisol secretion were not stimulated by induced hypotension to MAP of 60 mm Hg before surgery. Increased aldosterone secretion occurred and a further study with a larger sample size is needed.     

Mechanical compression with secondary ischemia as a possible cause of atresias associated with omphalocele

We report 2 cases of omphalocele associated with intestinal atresia. In the context of this unusual sequence, we discuss the etiopathogenesis of intestinal atresias in association with tight abdominal wall defects.     

A panel interview on the ethical practice of neuropsychology

Neuropsychologists who have considerable experience reflecting, presenting, publishing, and advising on ethical matters are a rich resource for clinicians who have ethics questions. Consultation with such colleagues can be an important part of the ethical decision-making process. The purpose of the present article is to provide the opinions and perspectives of three neuropsychologists who, based on their experience and scholarly activities, served as panelists regarding ethical matters. Although the advice and opinions of colleagues are not a substitute for familiarity with relevant ethical requirements, guidelines, and professional literature, they offer valuable information that enhances the ethical decision-making process.     

Pipping success and liver mRNA expression in chicken embryos exposed in ovo to C8 and C11 perfluorinated carboxylic acids and C10 perfluorinated sulfonate

Several perfluoroalkyl compounds (PFCs) are ubiquitous environmental contaminants that can biomagnify in species at high trophic levels including wild birds. Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) have been detected in wild birds and are known to reduce hatching success of laboratory-exposed chicken embryos at environmentally relevant concentrations. Limited toxicity data are available regarding avian exposure to PFCs of chain lengths greater than C₈, which are of increasing environmental relevance following the recent phase-out of PFOS and PFOA. In this study, linear PFOA, perfluoroundecanoic acid (PFUdA) and perfluorodecane sulfonate (PFDS) were injected into the air cell of white leghorn chicken eggs (Gallus gallus domesticus) prior to incubation to determine effects on embryo pipping success. Furthermore, mRNA expression of key genes involved in pathways implicated in PFC toxicity was monitored in liver tissue. PFOA, PFUdA or PFDS had no effect on embryonic pipping success at concentrations up to 10 μg/g. All PFCs accumulated in the liver to concentrations greater than the initial whole-egg concentration as determined by HPLC/MS/MS. Hepatic accumulation was highest for PFOA (4.5 times) compared to PFUdA and PFDS. Cytochrome P450 1A4 and liver fatty acid binding protein mRNA expression increased after exposure to PFUdA but was only statistically significant at 10 μg/g; several orders of magnitude higher than levels found in wild bird eggs. Based on the present results for white leghorn chickens, current environmental concentrations of PFOA, PFUdA and PFDS are unlikely to affect the hatching success of wild birds.     

A pilot study of compositional analysis of the breast and estimation of breast mammographic density using three-dimensional T1-weighted magnetic resonance imaging

PURPOSE: A method and computer tool to estimate percentage magnetic resonance (MR) imaging (MRI) breast density using three-dimensional T(1)-weighted MRI is introduced, and compared with mammographic percentage density [X-ray mammography (XRM)]. MATERIALS AND METHODS: Ethical approval and informed consent were obtained. A method to assess MRI breast density as percentage volume occupied by water-containing tissue on three-dimensional T(1)-weighted MR images is described and applied in a pilot study to 138 subjects who were imaged by both MRI and XRM during the Magnetic Resonance Imaging in Breast Screening study. For comparison, percentage mammographic density was measured from matching XRMs as a ratio of dense to total projection areas scored visually using a 21-point score and measured by applying a two-dimensional interactive program (CUMULUS). The MRI and XRM percent methods were compared, including assessment of left-right and interreader consistency. RESULTS: Percent MRI density correlated strongly (r = 0.78; P < 0.0001) with percent mammographic density estimated using Cumulus. Comparison with visual assessment also showed a strong correlation. The mammographic methods overestimate density compared with MRI volumetric assessment by a factor approaching 2. DISCUSSION: MRI provides direct three-dimensional measurement of the proportion of water-based tissue in the breast. It correlates well with visual and computerized percent mammographic density measurements. This method may have direct application in women having breast cancer screening by breast MRI and may aid in determination of risk.