Multifactorial Genetic and Environmental Hedgehog Pathway Disruption Sensitizes Embryos to Alcohol-Induced Craniofacial Defects

Background

Prenatal alcohol exposure (PAE) is perhaps the most common environmental cause of human birth defects. These exposures cause a range of structural and neurological defects, including facial dysmorphologies, collectively known as fetal alcohol spectrum disorders (FASD). While PAE causes FASD, phenotypic outcomes vary widely. It is thought that multifactorial genetic and environmental interactions modify the effects of PAE. However, little is known of the nature of these modifiers. Disruption of the Hedgehog (Hh) signaling pathway has been suggested as a modifier of ethanol teratogenicity. In addition to regulating the morphogenesis of craniofacial tissues commonly disrupted in FASD, a core member of the Hh pathway, Smoothened, is susceptible to modulation by structurally diverse chemicals. These include environmentally prevalent teratogens like piperonyl butoxide (PBO), a synergist found in thousands of pesticide formulations.

Methods

Here, we characterize multifactorial genetic and environmental interactions using a zebrafish model of craniofacial development.

Results

We show that loss of a single allele of shha sensitized embryos to both alcohol- and PBO-induced facial defects. Co-exposure of PBO and alcohol synergized to cause more frequent and severe defects. The effects of this co-exposure were even more profound in the genetically susceptible shha heterozygotes.

Conclusions

Together, these findings shed light on the multifactorial basis of alcohol-induced craniofacial defects. In addition to further implicating genetic disruption of the Hh pathway in alcohol teratogenicity, our findings suggest that co-exposure to environmental chemicals that perturb Hh signaling may be important variables in FASD and related craniofacial disorders.

     

Human platelets attenuate Aspergillus species via granule-dependent mechanisms

Using laser scanning microscopy, we investigated whether platelets are capable of internalizing Aspergillus conidia and examined Aspergillus-platelet adherence. The influence of platelets on fungal growth was evaluated by assessing galactomannan (GM) release, hyphal elongation, and colony size. A secretion assay with [(3)H]-serotonin (5-hydroxytryptamine [5-HT]) was performed. Exposure to platelets resulted in significantly decreased GM release (p<.05), hyphal elongation (p<.001), colony size, pigmentation, and 5-HT release ( p<.05). A lack of antifungal effects was observed with the microfilament inhibitor cytochalasin D. Platelets attenuate the virulence of Aspergillus species in vitro on the basis of granule-dependent effects.     

Resting Heart Rate Variability: Exploring Associations With Symptom Severity in Adults With Substance Use Disorders and Posttraumatic Stress

Objective: Substance use disorders and posttraumatic stress symptoms are commonly comorbid. Previous studies have established that those with substance use disorders or posttraumatic stress disorder (PTSD) have lower high frequency-heart rate variability (HF-HRV) compared to controls, suggesting that low HF-HRV may be a biomarker of a common physiological mechanism underlying both disorders. We evaluated HF-HRV as a potential biomarker of a common underlying process by testing whether lower HF-HRV related to greater severity of substance use and PTSD symptoms in individuals with both substance use disorders and at least four symptoms of PTSD. Methods: HF-HRV was measured in 49 adults with substance use disorders and at least four symptoms of PTSD. We performed a series of regressions controlling for age to test whether low HF-HRV was associated with greater substance use disorder and PTSD symptom severity. Substance use disorder symptoms were measured by the Addiction Severity Index and PTSD symptoms were measured by the Clinician-Administered PTSD Scale and the PTSD Checklist. Results: After controlling for age, low resting HF-HRV was significantly associated with drug and alcohol symptom severity but not PTSD symptom severity. Conclusions: HF-HRV may be more sensitive to the severity of drug and alcohol use rather than PTSD. Findings may suggest that in PTSD populations, HF-HRV may primarily index comorbid substance use disorder symptoms. HF-HRV could serve as an objective measure of substance use severity and should be further investigated as a predictor of outcomes in treatment for substance use disorders.     

A comparison of the diagnostic accuracy of MARS MRI and ultrasound of the painful metal-on-metal hip arthroplasty

Background and purpose

Metal artifact reduction sequence (MARS) MRI and ultrasound scanning (USS) can both be used to detect pseudotumors, abductor muscle atrophy, and tendinous pathology in patients with painful metal-on-metal (MOM) hip arthroplasty. We wanted to determine the diagnostic test characteristics of USS using MARS MRI as a reference for detection of pseudotumors and muscle atrophy.

Patients and methods

We performed a prospective cohort study to compare MARS MRI and USS findings in 19 consecutive patients with unilateral MOM hips. Protocolized USS was performed by consultant musculoskeletal radiologists who were blinded regarding clinical details. Reports were independently compared with MARS MRI, the imaging gold standard, to calculate predictive values.

Results

The prevalence of pseudotumors on MARS MRI was 68% (95% CI: 43–87) and on USS it was 53% (CI: 29–76). The sensitivity of USS in detecting pseudotumors was 69% (CI 39–91) and the specificity was 83% (CI: 36–97). The sensitivity of detection of abductor muscle atrophy was 47% (CI: 24–71). In addition, joint effusion was detected in 10 cases by USS and none were seen by MARS MRI.

Interpretation

We found a poor agreement between USS and MARS MRI. USS was inferior to MARS MRI for detection of pseudotumors and muscle atrophy, but it was superior for detection of joint effusion and tendinous pathologies. MARS MRI is more advantageous than USS for practical reasons, including preoperative planning and longitudinal comparison.Approximately 1.5 million metal-on-metal (MOM) hip arthroplasties have been implanted worldwide since 1996 (FDA 2012). A high early failure rate for these prostheses has recently been demonstrated (Smith et al. 2012). The pattern of failure appears to differ from other hip arthroplasty types, with adverse reactions to wear-related metal debris being a prominent feature (Pandit et al. 2008, Kwon et al. 2011). These solid or cystic lesions have been termed pseudotumors (Pandit et al. 2008). A wide spectrum of adverse tissue reactions have been described. Histologically, using their pseudocapsules, these have been termed aseptic lymphocytic vasculitis-associated lesions (ALVALs) (Willert et al. 2005).Health regulatory guidelines recommend investigation with cross-sectional imaging, using either metal artifact reduction sequence (MARS) MRI or ultrasound scanning (USS), to evaluate the periprosthetic soft tissues. A number of advantages and disadvantages have been reported (Sabah et al. 2011, Liddle et al. 2013). The high-resolution capability of USS allows detailed imaging of solid or cystic extra-articular lesions and also detection of muscle atrophy (Sofka et al. 2004), joint effusions, gluteal tendon avulsion, and iliopsoas or trochanteric bursitis (Long et al. 2012). USS is also commonly used during guided anesthetic injection or fluid aspiration.

Table 1.

A comparison of the advantages and disadvantages of MARS MRI and ultrasound imaging of metal-on-metal hips

PEComa of the Nose: Report of a Case with Immunohistochemical and Ultrustructural Studies and a Review of the Literature

PEComas are a family of mesenchymal neoplasms that have in common the presence of a unique cell type, the perivascular epithelioid cell (PEC). PECs uniquely exhibit a distinct immunophenotype with expression of both melanocytic, particularly HMB-45, and myogenic markers. Nasal PEComas are exceedingly rare. To date, 14 cases have been described in the literature and with the exception of 6 cases, the rest consistently lack epithelioid cells and HMB-45 expression and are best classified as nasal hamartomas or angioleiomyomas with an adipocytic component. Nasal PEComas may closely resemble malignant melanomas since both entities share many morphologic, immunohistochemical, ultrastructural and clinical features. The distinction is of paramount importance as melanomas tend to display an aggressive behaviour with associated poor outcome. Herein, we report a case of nasal PEComa in a 19 year girl, focusing on the importance of light microscopic, immunohistochemical and ultrastructural features in accurately establishing the diagnosis.     

Vaccination with a piggyBac plasmid with transgene integration potential leads to sustained antigen expression and CD8 T cell responses

DNA vaccination with plasmid has conventionally involved vectors designed for transient expression of antigens in injected tissues. Next generation plasmids are being developed for site-directed integration of transgenes into safe sites in host genomes and may provide an innovative approach for stable and sustained expression of antigens for vaccination. The goal of this study was to evaluate in vivo antigen expression and the generation of cell mediated immunity in mice injected with a non-integrating plasmid compared to a plasmid with integrating potential. Hyperactive piggyBac transposase-based integrating vectors (pmhyGENIE-3) contained a transgene encoding either eGFP (pmhyGENIE-3-eGFP) or luciferase (pmhyGENIE-3-GL3), and were compared to transposase-deficient plasmids with the same transgene and DNA backbone. Both non-integrating and integrating plasmids were equivalent at day 1 for protein expression at the site of injection. While protein expression from the non-integrating plasmid was lost by day 14, the pmhyGENIE-3 was found to exhibit sustained protein expression up to 28 days post-injection. Vaccination with pmhyGENIE-3-eGFP resulted in a robust CD8⁺ T cell response that was three-fold higher than that of non-integrating plasmid vaccinations. Additionally we observed in splenocyte restimulation experiments that only the vaccination with pmhyGENIE-3-eGFP was characterized by IFNγ producing CD8⁺ T cells. Overall, these findings suggest that plasmids designed to direct integration of transgenes into the host genome are a promising approach for designing DNA vaccines. Robust cell mediated CD8⁺ T cell responses generated using integrating plasmids may provide effective, sustained protection against intracellular pathogens or tumor antigens.