Abstract 1978: Demonstrating a role for nuclear Adenomatous polyposis coli in intestinal cell differentiation

Colon cancer is the second leading cause of cancer-related mortality in the United States, resulting in over 50,000 deaths annually. Approximately 80% of colon cancers begin with a mutation in the gene coding for the tumor suppressor protein Adenomatous Polyposis Coli, APC. APC protein can shuttle between the cytoplasm and the nucleus of cells, facilitated by two nuclear localization signals (NLS) and multiple nuclear export signals. To better understand functions of nuclear APC, our lab generated a “knock-in” mouse model with mutations introduced that inactivate both Apc NLS. These ApcmNLS/mNLS mice show a dramatic decrease in nuclear Apc. We previously showed increased proliferation and Wnt target gene expression in intestinal epithelial cells from ApcmNLS/mNLS mice, suggesting a role for nuclear APC in inhibition of proliferation and Wnt signaling. We also showed increased tumor number and size in ApcMin mice if they also harbor the ApcmNLS allele. Here we examine the role of nuclear Apc in intestinal epithelial differentiation and stem cell homeostasis. Paraffin-embedded tissue from the intestines of Apc+/+ and ApcmNLS/mNLS mice was sectioned and stained for markers of enterocytes (alkaline phosphatase) and goblet cells (alcian blue). Quantification of the positive cells indicated that ApcmNLS/mNLS mice had fewer differentiated enterocytes and goblet cells than their wild-type littermates. Intestines from ApcmNLS/mNLS mice were also stained for markers of quiescent and active stem cells, DCAMKL-1 and Lgr5 respectively. Quantification of the various stem cell populations will be described. Together, our data supports a role for nuclear Apc in promoting enterocyte and goblet cell differentiation, in suppression of tumors, and in inhibiting intestinal cell proliferation and Wnt signaling. Information gathered from analysis of ApcmNLS/mNLS mice will contribute to our understanding of the functions of nuclear APC in tumor suppression and ultimately the mechanism of intestinal tumorigenesis.

Citation Format: Matthew A. Miller, Maged Zeineldin, Kristi L. Neufeld. Demonstrating a role for nuclear Adenomatous polyposis coli in intestinal cell differentiation. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1978. doi:10.1158/1538-7445.AM2013-1978

Immunohistochemical evaluation of the effects of paraffin section storage on biomarker stability

Environmental stresses can alter immunoreactivity of biomarkers in stored tissue sections. The effect of temperature and lighting on 49 cellular or microbial antigens was evaluated in 4 serial paraffin sections, cut 12 months, 10 months, 8 months, 5 months, 3 months, 1 month, 3 days, and 1 day before immunohistochemistry. Slides were stored at room temperature (RT) in the dark, at 4°C in the dark, at RT under fluorescent light, or at RT with windowpane exposure to sunlight. Immunohistochemistry was performed simultaneously in an automated immunostainer. Immunoreactivity was compared with that in the corresponding 1-day-old section and scored as 4 (<10% reduction), 3 (10%-25% reduction), 2 (26%-60% reduction), 1(>60% reduction), or 0 (no reactivity). Any loss of immunoreactivity was proportional to the tissue section age and was least in sections stored in the dark. Immunoreactivity was only completely lost in light-exposed sections and as early as 1 month for CD45. Other markers with complete loss of immunoreactivity were bovine viral diarrhea virus, CD18 (only with fluorescent light), CD31, CD68, canine parvovirus, chromogranins, and thyroid transcription factor-1. Markers with complete loss after light exposure also had reduced immunoreactivity when stored in the dark, as early as day 3. Eight markers (Bartonella spp, CD11d, high molecular weight cytokeratins, feline coronavirus, GATA-4, insulin, p63, progesterone receptor) had minimal decrease in immunoreactivity, regardless of treatment. In conclusion, light-induced antigen decay (tissue section aging) is antigen dependent and could explain unexpectedly weak or negative immunohistochemical reactions in stored paraffin sections.

Design and performance of a spreadsheet-based model for estimating bioavailability of chemicals from dermal exposure

A comprehensive transient model of chemical penetration through the stratum corneum, viable epidermis and dermis formulated in terms of an Excel™ spreadsheet and associated add-in is presented. The model is a one-dimensional homogenization of underlying microscopic transport models for stratum corneum and dermis; viable epidermis is treated as unperfused dermis. The model's salient features are a detailed structural description of the skin layers, a combination of first-principles based transport equations and empirical partition and diffusion coefficients, and the capability of simulating a variety of exposure scenarios. Model predictions are compared with representative in vitro skin permeation data obtained from the literature using as summary parameters total absorption (Q(abs)), maximum flux (J(max)) and skin permeability coefficient (k(p)). The results of this evaluation demonstrate the current state-of-the-art in prediction of transient skin absorption and highlight areas in which further elaborations are needed to obtain satisfactory predictions.

Correlation of inflammation with adrenocortical atrophy in canine adrenalitis

Hypoadrenocorticism or Addison's disease (AD) is a functional disorder in which insufficient mineralocorticoid and glucocorticoid hormones are produced by the adrenal cortex. Human AD is usually attributed to lymphoplasmacytic adrenalitis with autoimmune destruction of the adrenal cortex. Lymphoplasmacytic adrenalitis is also reported in some descriptions of canine AD; however, the histological aspects of adrenalitis or adrenocortical atrophy have not been well characterized because microscopical examination is not required for diagnosis of AD. In this study, sections of adrenal glands from 33 dogs with adrenalitis were compared with those of 37 dogs without adrenal lesions. The affected dogs were classified clinically as having AD (n = 3), being suspected of having AD (n = 17), not having AD (n = 11) or were unclassified (n = 2). The adrenal inflammation was lymphoplasmacytic in 17 dogs, lymphocytic in four, lymphohistiocytic in one, granulomatous in three and neutrophilic in eight cases. Adrenal glands from control dogs lacked leucocyte infiltration and had a cortical to medullary area ratio of 1.1-7.2. All three dogs with AD, 8/17 dogs with suspected AD and 1/11 dogs without AD had a cortical to medullary area ratio <1.1. Because the area ratio was correlated (r = 0.94) with a linear cortical to medullary thickness ratio, a thickness ratio <1.1 could also indicate severe adrenocortical atrophy. Severe adrenocortical atrophy was associated typically with lymphoplasmacytic infiltration and nearly complete loss of cortical cells; however, the zona glomerulosa was partially spared in three dogs with lymphoplasmacytic adrenalitis and severe cortical atrophy. In contrast, non-lymphoid inflammation was generally part of systemic disease, multifocal and was unaccompanied by severe adrenocortical atrophy.

Comparison of titanium soaked in 5 M NaOH or 5 M KOH solutions

Commercially pure titanium plates/coupons and pure titanium powders were soaked for 24 h in 5 M NaOH and 5 M KOH solutions, under identical conditions, over the temperature range of 37° to 90 °C. Wettability of the surfaces of alkali-treated cpTi coupons was studied by using contact angle goniometry. cpTi coupons soaked in 5 M NaOH or 5 M KOH solutions were found to have hydrophilic surfaces. Hydrous alkali titanate nanofibers and nanotubes were identified with SEM/EDXS and grazing incidence XRD. Surface areas of Ti powders increased > 50–220 times, depending on the treatment, when soaked in the above solutions. A solution was developed to coat amorphous calcium phosphate, instead of hydroxyapatite, on Ti coupon surfaces. In vitro cell culture tests were performed with osteoblast-like cells on the alkali-treated samples.

Cutaneous metastasis of transitional cell carcinoma in 12 dogs

In humans, cutaneous metastasis of transitional cell carcinoma (TCC) has been attributed to direct extension, lymphatic or hematogenous dissemination, or surgical implantation. The purpose of this study was to characterize the clinical and histologic features of cutaneous TCC metastasis, confirmed by uroplakin-III immunohistochemistry, in dogs. The 12 cases were 9 spayed female and 3 neutered male dogs, 6 to 14 years old (mean, 11 years). Four dogs had a history of urinary incontinence. Three had undergone abdominal surgery for TCC diagnosis or treatment. The primary neoplasms were 7 papillary infiltrating and 5 nonpapillary infiltrating TCC. Cutaneous lesions were detected at a mean of 123 days (median, 38 days) after diagnosis of the primary TCC and appeared as plaques, papules, or nodules in, with 1 exception, perineal, inguinal, or ventral abdominal dermis or subcutis. Of 8 dogs with dermal TCC, 5 had epidermal erosion or ulceration. In 10 dogs, TCC was detected in cutaneous lymphatic vessels, identified by endothelial immunoreactivity for Prox1. Metastases were also detected in lymph nodes in all dogs and at distant noncutaneous sites, usually the lungs, in 10 dogs. Mean survival after diagnosis was 162 days (median, 90 days). Despite medical treatment of 10 dogs after the development of cutaneous metastasis, remission was not achieved; 4 dogs had stable disease. Although TCC could have spread to skin by direct extension or lymphatic or vascular dissemination, the proximity of most cutaneous metastases to the vulva or prepuce raises the additional possibility of transepidermal spread through urine-scalded skin.

Androgen receptor gene expression in the rat central nervous system: Evidence for two mRNA transcripts

Androgen receptor (AR) gene expression in the central nervous system (CNS) and peripheral tissues of male rats was examined using cDNA probes to measure AR mRNA by RNA (Northern) blot analysis and by in situ hybridization. Using a probe from the 5' untranslated region of the rat cDNA (AR-1), a single mRNA species of approximately 11 kb was seen in Northern blots of poly(A)(+) RNA from reproductive tissues, kidney, liver, and muscle. Using a probe from the 5' end of the coding region (AR-2), in addition to the 11-kb band, a novel transcript was seen in whole brain at about 9.3 kb. In poly(A)(+) RNA from dissected brain regions, the 9.3-kb transcript was predominant in the cortex, cerebellum, and brain stem, while in the hippocampus, both transcripts were expressed to a similar degree. AR mRNA levels increased two- to threefold in the prostate on Days 1 and 3 following castration but no significant change was seen in either CNS transcript in whole brain or cortex. Specific in situ hybridization of an (35)S-labeled AR-2 riboprobe was observed in brain regions known to bind radiolabeled androgens. We conclude that two AR RNA species exist in the adult male rat which differ in their 5' untranslated region and that the relative proportion of the two species varies between brain regions. In contrast to observations in the prostate, AR gene expression in the cerebral cortex is not regulated in the short term by androgen withdrawal.

Hyperleptinemia is associated with hypertension, systemic inflammation and insulin resistance in overweight but not in normal weight men

BACKGROUND AND AIM

High leptin (LPT) is associated with high blood pressure (BP), insulin resistance and systemic inflammation but also excess body weight and adiposity. To disentangle these multiple relations, we analyzed BP, HOMA and circulating C-reactive protein concentration (hs-CRP) in white male adults with different LPT levels but similar age, body mass index (BMI) and body fat distribution. The novel aspect is the different statistical approach used to investigate the relation between LPT and the other alterations present in obesity.

METHODS AND RESULTS

972 Olivetti Heart Study participants were stratified according to the median LPT distribution (2.97 ng/ml) into low LPT (l-LPT) and high LPT (h-LPT). The two groups were then carefully matched for age and BMI. We identified two groups of 207 h-LPT and 207 l-LPT individuals with overlapping age, BMI and waist/hip ratio. The two groups had different BP (132.9 ± 16.2/85.7 ± 9.0 vs 128.7 ± 18.2/82.8 ± 9.8 mmHg, p = 0.014 for SBP and p = 0.002 for DBP) and prevalence of hypertension (57% vs 43%, p = 0.027). Upon separate evaluation of untreated individuals with BMI < 25 or BMI ≥ 25, within the latter subgroup h-LPT compared with l-LPT participants (n = 133 each group) had higher BP (p = 0.0001), HOMA index (p = 0.013), hs-CRP (p = 0.002) and heart rate (p = 0.008) despite similar age and BMI. By contrast, within the normal weight subgroup, h-LPT individuals did not differ from l-LPT (n = 37 each) for any of these variables.

CONCLUSIONS

High LPT is associated with higher BP, HR, hs-CRP and HOMA index independently of BMI and fat distribution but only among overweight individuals.

Comparison of CD34, CD31, and factor VIII-related antigen immunohistochemical expression in feline vascular neoplasms and CD34 expression in feline nonvascular neoplasms

The diagnosis of vascular neoplasms is often facilitated by the use of immunohistochemical markers such as factor VIII-related antigen, CD31, and CD34. However, the relative sensitivity and specificity of these markers have not been compared in cat vascular neoplasms. In this study, these 3 immunohistochemical markers were evaluated in 61 endothelial neoplasms (50 hemangiosarcomas and 11 hemangiomas) in 59 cats. All neoplasms were labeled by all 3 markers. CD34 had the highest average immunolabeling intensity in neoplastic endothelial cells. CD31 had the lowest average background labeling, followed by CD34 and factor VIII-related antigen, respectively. CD34 expression was also examined in 130 nonvascular neoplasms of cats; 14 of 62 epithelial neoplasms, 39 of 43 mesenchymal neoplasms, 8 of 23 leukocytic neoplasms, and 2 of 2 melanomas were positive. Given the broad expression of CD34 in mesenchymal neoplasms, this marker has limited diagnostic relevance for vascular neoplasms of cats.

The 1918-1920 influenza pandemic in Peru

BACKGROUND

Increasing our knowledge of past influenza pandemic patterns in different regions of the world is crucial to guide preparedness plans against future influenza pandemics. Here, we undertook extensive archival collection efforts from three representative cities of Peru-Lima in the central coast, Iquitos in the northeastern Amazon region, Ica in the southern coast-to characterize the temporal, age and geographic patterns of the 1918-1920 influenza pandemic in this country.

MATERIALS AND METHODS

We analyzed historical documents describing the 1918-1920 influenza pandemic in Peru and retrieved individual mortality records from local provincial archives for quantitative analysis. We applied seasonal excess mortality models to daily and monthly respiratory mortality rates for 1917-1920 and quantified transmissibility estimates based on the daily growth rate in respiratory deaths.

RESULTS

A total of 52,739 individual mortality records were inspected from local provincial archives. We found evidence for an initial mild pandemic wave during July-September 1918 in Lima, identified a synchronized severe pandemic wave of respiratory mortality in all three locations during November 1918-February 1919, and a severe pandemic wave during January 1920-March 1920 in Lima and July-October 1920 in Ica. There was no recrudescent pandemic wave in 1920 in Iquitos. Remarkably, Lima experienced the brunt of the 1918-1920 excess mortality impact during the 1920 recrudescent wave, with all age groups experiencing an increase in all cause excess mortality from 1918-1919 to 1920. Middle age groups experienced the highest excess mortality impact, relative to baseline levels, in the 1918-1919 and 1920 pandemic waves. Cumulative excess mortality rates for the 1918-1920 pandemic period were higher in Iquitos (2.9%) than Lima (1.6%). The mean reproduction number for Lima was estimated in the range 1.3-1.5.

CONCLUSIONS

We identified synchronized pandemic waves of intense excess respiratory mortality during November 1918-February 1919 in Lima, Iquitos, Ica, followed by asynchronous recrudescent waves in 1920. Cumulative data from quantitative studies of the 1918 influenza pandemic in Latin American settings have confirmed the high mortality impact associated with this pandemic. Further historical studies in lesser studied regions of Latin America, Africa, and Asia are warranted for a full understanding of the global impact of the 1918 pandemic virus.

The value of biomedical research training for veterinary anatomic and clinical pathologists

Veterinary pathologists traditionally have been actively engaged in research as principal investigators and as collaborators. Pathologists frequently obtain advanced training in research; however, it appears that in the last 10 years there has been a reversal of a previous trend toward increasing numbers of pathologists obtaining PhD degrees. This has arisen despite an established shortage of veterinarians engaged in research. This article evaluates the benefits of research training for individual pathologists, including a wide spectrum of professional opportunities and additional skill development beyond that usually provided by diagnostic pathology training alone. Various training models are discussed, including combined and sequential diagnostic residency and research degree training as well as the nondegree research fellowship programs more commonly pursued in human medicine. Best-practice recommendations for program infrastructure, mentorship, time management, and a team approach to research and research training are advocated to facilitate the development of successful programs and to encourage a continued emphasis on integrated training for pathologists as both clinical diagnosticians and experimentalists. This article is intended to help prospective and active pathology trainees, their mentors, and educational administrators optimize opportunities to ensure the future vitality of veterinary pathologists, and their contributions, in basic and applied research.

Afriflu--international conference on influenza disease burden in Africa, 1-2 June 2010, Marrakech, Morocco

The burden of influenza disease is to a large extent unknown for the African continent. Moreover, the interaction of influenza with common infectious diseases in Africa remains poorly described. Solid scientific evidence on the influenza disease burden in Africa is critical for the development of effective influenza vaccine policies. On 1st and 2nd June 2010 in Marrakech, Morocco, over eighty surveillance and influenza experts from 22 African countries as well as Europe and America met at the 'Afriflu' conference to discuss influenza challenges and solutions for the continent. During the meeting, participants exchanged their experiences and discussed a wide variety of topics related to influenza in Africa, including diagnosis, surveillance, epidemiology, and interventions. The meeting concluded with a pledge to improve influenza knowledge and awareness in Africa, with an emphasis on accurate determination of disease burden to help orient public health policies.

Proposal of a 2-tier histologic grading system for canine cutaneous mast cell tumors to more accurately predict biological behavior

Currently, prognostic and therapeutic determinations for canine cutaneous mast cell tumors (MCTs) are primarily based on histologic grade. However, the use of different grading systems by veterinary pathologists and institutional modifications make the prognostic value of histologic grading highly questionable. To evaluate the consistency of microscopic grading among veterinary pathologists and the prognostic significance of the Patnaik grading system, 95 cutaneous MCTs from 95 dogs were graded in a blinded study by 28 veterinary pathologists from 16 institutions. Concordance among veterinary pathologists was 75% for the diagnosis of grade 3 MCTs and less than 64% for the diagnosis of grade 1 and 2 MCTs. To improve concordance among pathologists and to provide better prognostic significance, a 2-tier histologic grading system was devised. The diagnosis of high-grade MCTs is based on the presence of any one of the following criteria: at least 7 mitotic figures in 10 high-power fields (hpf); at least 3 multinucleated (3 or more nuclei) cells in 10 hpf; at least 3 bizarre nuclei in 10 hpf; karyomegaly (ie, nuclear diameters of at least 10% of neoplastic cells vary by at least two-fold). Fields with the highest mitotic activity or with the highest degree of anisokaryosis were selected to assess the different parameters. According to the novel grading system, high-grade MCTs were significantly associated with shorter time to metastasis or new tumor development, and with shorter survival time. The median survival time was less than 4 months for high-grade MCTs but more than 2 years for low-grade MCTs.

Response conflict as an environmental determinant of gender differences in sensitivity to alcohol impairment

The majority of research examining gender differences in alcohol impairment has found greater impairment in women. However, some studies report greater responsivity in men, particularly in situations involving competing response tendencies (e.g., inhibitory control and aggression tasks), suggesting that response conflict could account for these contradictory findings. Drawing on data from previous experiments conducted in our laboratory, the current study examined this hypothesis by comparing the alcohol sensitivity of gender groups on a broad range of behavioral tasks. Tasks were categorized as high or low conflict based on whether tasks involved competing response tendencies. Results showed that women displayed greater impairment from alcohol than men on low conflict tasks, and men were more impaired than women on high conflict tasks. These findings suggest that response conflict might play an important role in the occasional and contradictory observations in which men demonstrate more intense behavioral reactions to alcohol than women.

Phylogeography of ninespine sticklebacks (Pungitius pungitius) in North America: glacial refugia and the origins of adaptive traits

The current geographical distribution of the ninespine stickleback (Pungitius pungitius) was shaped in large part by the glaciation events of the Pleistocene epoch (2.6 Mya-1 Kya). Previous efforts to elucidate the phylogeographical history of the ninespine stickleback in North America have focused on a limited set of morphological traits, some of which are likely subject to widespread convergent evolution, thereby potentially obscuring relationships among populations. In this study, we used genetic information from both mitochondrial DNA (mtDNA) sequences and nuclear microsatellite markers to determine the phylogenetic relationships among ninespine stickleback populations. We found that ninespine sticklebacks in North America probably dispersed from at least three glacial refugia-the Mississippi, Bering, and Atlantic refugia-not two as previously thought. However, by applying a molecular clock to our mtDNA data, we found that these three groups diverged long before the most recent glacial period. Our new phylogeny serves as a critical framework for examining the evolution of derived traits in this species, including adaptive phenotypes that evolved multiple times in different lineages. In particular, we inferred that loss of the pelvic (hind fin) skeleton probably evolved independently in populations descended from each of the three putative North American refugia.

Using 'subcement' to simulate the long-term fatigue response of cemented femoral stems in a cadaver model: could a novel preclinical screening test have caught the Exeter matt problem?

Previously, cement was formulated with degraded fatigue properties (subcement) to simulate long-term fatigue in short-term cadaver tests. The present study determined the efficacy of subcement in a 'preclinical' test of a design change with known clinical consequences: the 'polished'-to-'matt' transition of the Exeter stem (revision rates for polished stems were twice those for matt stems). Contemporary stems were bead blasted to give Ra = 1 microm (matt finish). Matt and polished stems were compared in cadaver pairs under stair-climbing loads (three pairs of size 1; three pairs of size 3). Stem micromotion was monitored during loading. Post-test transverse sections were examined for cement damage. Cyclic retroversion decreased for polished stems but increased for matt stems (p < 0.0001). The implant size had a substantial effect; retroversion of (larger) size-3 stems was half that of size-1 stems, and polished size-3 stems subsided 2.5 times more than the others. Cement damage measures were similar and open through-cracks occurred around both stems of two pairs. Stem retroversion within the mantle resulted in stem-cement gaps of 50-150 microm. Combining information on cyclic motion, cracks, and gaps, it was concluded that this test 'predicted' higher revision rates for matt stems (it also implied that polished size-3 stems might be superior to size-1 stems).

Impact of vaccination and birth rate on the epidemiology of pertussis: a comparative study in 64 countries

Bordetella pertussis infection remains an important public health problem worldwide despite decades of routine vaccination. A key indicator of the impact of vaccination programmes is the inter-epidemic period, which is expected to increase with vaccine uptake if there is significant herd immunity. Based on empirical data from 64 countries across the five continents over the past 30-70 years, we document the observed relationship between the average inter-epidemic period, birth rate and vaccine coverage. We then use a mathematical model to explore the range of scenarios for duration of immunity and transmission resulting from repeat infections that are consistent with empirical evidence. Estimates of pertussis periodicity ranged between 2 and 4.6 years, with a strong association with susceptible recruitment rate, defined as birth rate × (1 - vaccine coverage). Periodicity increased by 1.27 years on average after the introduction of national vaccination programmes (95% CI: 1.13, 1.41 years), indicative of increased herd immunity. Mathematical models suggest that the observed patterns of pertussis periodicity are equally consistent with loss of immunity that is not as rapid as currently thought, or with negligible transmission generated by repeat infections. We conclude that both vaccine coverage and birth rate drive pertussis periodicity globally and that vaccination induces strong herd immunity effects. A better understanding of the role of repeat infections in pertussis transmission is critical to refine existing control strategies.

Toward a better understanding of pesticide dermal absorption: diffusion model analysis of parathion absorption in vitro and in vivo

Human skin absorption of radiolabeled parathion was studied in vitro at specific doses (mass loadings) of 0.4, 4.0, 41, or 117 microg/cm(2), with and without occlusion. The compound was applied in small volumes of acetone solution to split-thickness skin. Permeation of radiolabel into the receptor solutions was monitored for 76 h, after which the tissue was dissected and analyzed for residual radioactivity. For the 3 lower doses, cumulative permeation after 76 h was approximately dose-proportional, ranging from 28.5-30.5% of applied dose (unoccluded) to 45.5-55.7% (occluded). Total absorption, calculated as receptor fluid plus dermis content, followed a similar pattern. Both permeation rate and total absorption continued to increase up to the highest dose tested, consistent with results from other laboratories. These results are compared with predictions from a previously developed skin diffusion model (Kasting et al., 2008a). The model predicted total absorption to within a factor of 1.4 at 0.4 microg/cm(2) and 1.6 at 4 microg/cm(2), but substantially underpredicted absorption at the 2 higher doses. The analysis showed that parathion partitioned more favorably into the stratum corneum than the diffusion model prediction. Nevertheless, comparison of the model predictions to a previously reported human study showed that the skin absorption model, when corrected for surface losses occurring in vivo, satisfactorily described in vivo dermal absorption of parathion applied at 4 microg/cm(2) to various body sites.

Limited genetic diversity among Sarcocystis neurona strains infecting southern sea otters precludes distinction between marine and terrestrial isolates

Sarcocystis neurona is an apicomplexan parasite identified as a cause of fatal neurological disease in the threatened southern sea otter (Enhydra lutris nereis). In an effort to characterize virulent S. neurona strains circulating in the marine ecosystem, this study developed a range of markers relevant for molecular genotyping. Highly conserved sequences within the 18S ribosomal gene array, the plastid-encoded RNA polymerase (RPOb) and the cytochrome c oxidase subunit 1 mitochondrial gene (CO1) were assessed for their ability to distinguish isolates at the genus and species level. For within-species comparisons, five surface antigens (SnSAG1-SnSAG5) and one high resolution microsatellite marker (Sn9) were developed as genotyping markers to evaluate intra-strain diversity. Molecular analysis at multiple loci revealed insufficient genetic diversity to distinguish terrestrial isolates from strains infecting marine mammals. Furthermore, SnSAG specific primers applied against DNA from the closely related species, Sarcocystis falcatula, lead to the discovery of highly similar orthologs to SnSAG2, 3, and 4, calling into question the specificity of diagnostic tests based on these antigens. The results of this study suggest a population genetic structure for S. neurona similar to that reported for the related parasite, Toxoplasma gondii, dominated by a limited number of successful genotypes.

Novel methods to study functional loading micromechanics at the stem-cement and cement-bone interface in cemented femoral hip replacements

We have developed a technique to directly observe the micromechanics of the stem-cement and cement-bone interfaces of cemented femoral stems under physiologically relevant loading conditions. Thick transverse sections of a stem-cement-femur construct were fixed to the base of a test frame. Ante- and retro-verting torques were applied to the femoral stem by screwing the stem (via a pair of through holes) to an axle, which was turned using a lever arm actuated by the test frame cross-head. The surface of each transverse section was serially digitally imaged during loading. The displacements of the stem, cement and bone were determined using digital image correlation. These data were then used to calculate the relative displacements across the interfaces. This method provides a path to more thorough understanding of load-transfer from femoral stem to femur.

Focal amplification and oncogene dependency of GAB2 in breast cancer

DNA amplifications in breast cancer are frequent on chromosome 11q, in which multiple driver oncogenes likely reside in addition to cyclin D1 (CCND1). One such candidate, the scaffolding adapter protein, GRB2-associated binding protein 2 (GAB2), functions in ErbB signaling and was recently shown to enhance mammary epithelial cell proliferation, and metastasis of ERBB2 (HER2/neu)-driven murine breast cancer. However, the amplification status and function of GAB2 in the context of amplification remain undefined. In this study, by genomic profiling of 172 breast tumors, and fluorescence in situ hybridization validation in an independent set of 210 scorable cases, we observed focal amplification spanning GAB2 (11q14.1) independent of CCND1 (11q13.2) amplification, consistent with a driver role. Further, small interfering RNA (siRNA)-mediated knockdown of GAB2 in breast cancer lines (SUM52, SUM44PE and MDA468) with GAB2 amplification revealed a dependency on GAB2 for cell proliferation, cell-cycle progression, survival and invasion, likely mediated through altered phosphatidylinositol 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) signaling. GAB2 knockdown also reduced proliferation and survival in a cell line (BT474) with ERBB2 amplification, consistent with the possibility that GAB2 can function downstream of ERBB2. Our studies implicate focal amplification of GAB2 in breast carcinogenesis, and underscore an oncogenic role of scaffolding adapter proteins, and a potential new point of therapeutic intervention.

Radiofrequency-induced thermal inactivation of Toxoplasma gondii oocysts in water

Toxoplasma gondii, a ubiquitous parasitic protozoan, is emerging as an aquatic biological pollutant. Infections can result from drinking water contaminated with environmentally resistant oocysts. However, recommendations regarding water treatment for oocyst inactivation have not been established. In this study, the physical method of radiofrequency (RF) power was evaluated for its ability to inactivate T. gondii oocysts in water. Oocysts were exposed to various RF energy levels to induce 50, 55, 60, 70 and 80 degrees C temperatures maintained for 1 min. Post-treatment oocyst viability was determined by mouse bioassay with serology, immunohistochemistry and in vitro parasite isolation to confirm T. gondii infections in mice. None of the mice inoculated with oocysts treated with RF-induced temperatures of > or =60 degrees C in an initial experiment became infected; however, there was incomplete oocyst activation in subsequent experiments conducted under similar conditions. These results indicate that T. gondii oocysts may not always be inactivated when exposed to a minimum of 60 degrees C for 1 min. The impact of factors such as water heating time, cooling time and the volume of water treated must be considered when evaluating the efficacy of RF power for oocyst inactivation.

Low serum adiponectin predicts 10-year risk of type 2 diabetes and HbA1c independently of obesity, lipids, and inflammation: Whitehall II study

Our aim of the present work was to study the effect of serum adiponectin on incident diabetes and HbA1c values. We measured baseline serum adiponectin levels in a nested case-control selection (n=140) of the Whitehall II Cohort. Participants (mean [SD] age 50.9 [6.3] years) had no prevalent diabetes or CHD at baseline. Cases (n=55) had incident diabetes according to an oral glucose tolerance test during follow-up (mean: 11.5+/-3.0 years). Adiponectin levels were lower among cases (9.3 microg/ml, 3.2 [median; IQR] vs. 10.5; 3.6, p=0.01). The risk of incident diabetes decreased by 11% (p=0.03) for 1 microg/ml higher adiponectin levels. Higher adiponectin levels were associated with lower HbA1c at follow-up (p<0.05). Both associations were stable to adjustment for age, sex, body mass index, systolic blood pressure, and serum lipids, and for the case of HbA1c, also for C-reactive protein (all p<0.05). The observed robust, prospective associations support that adiponectin is an independent predictor of diabetes and the degree of glycaemic impairment.

Ultrastructural and molecular confirmation of the development of Sarcocystis neurona tissue cysts in the central nervous system of southern sea otters (Enhydra lutris nereis)

In 2004, three wild sea otters were diagnosed with putative Sarcocystis neurona-associated meningoencephalitis by histopathology and immunohistochemistry. Schizonts, free merozoites and tissue cysts were observed in the brains of all three infected animals. Tissue cysts walls from sea otter 1 (SO1) stained positively using anti-S. neurona polyclonal antiserum. However, positive staining does not preclude infection by closely related or cross-reactive tissue cyst-forming coccidian parasites. Two immature tissue cysts in the brain of SO1 were examined using transmission electron microscopy. Ultrastructural features included cyst walls with thin villous projections up to 1 microm long with tapered ends and a distinctive, electron-dense outer lining layer composed of linearly-arranged, semi-circular structures with a "hobnailed" surface contour. Small numbers of microtubules extended down through the villi into the underlying granular layer. Metrocytes were short and plump with an anterior apical complex, 22 sub-pellicular microtubules, numerous free ribosomes and no rhoptries. Some metrocytes appeared to be dividing, with two adjacent nuclear profiles. Collectively these ultrastructural features were compatible with developing protozoal cysts and were similar to prior descriptions of S. neurona tissue cysts. Panspecific 18S rDNA primers were utilized to identify protozoa infecting the brains of these otters and DNA amplification and additional sequencing at the ITS1 locus confirmed that all three otters were infected with S. neurona. No other Sarcocystis spp. were detected in the brains or skeletal muscles of these animals by immunohistochemistry or PCR. We believe this is the first ultrastructural and molecular confirmation of the development of S. neurona tissue cysts in the CNS of any animal.