Retrohoming of a Mobile Group II Intron in Human Cells Suggests How Eukaryotes Limit Group II Intron Proliferation.

Mobile bacterial group II introns are evolutionary ancestors of spliceosomal introns and retroelements in eukaryotes. They consist of an autocatalytic intron RNA (a "ribozyme") and an intron-encoded reverse transcriptase, which function together to promote intron integration into new DNA sites by a mechanism termed "retrohoming". Although mobile group II introns splice and retrohome efficiently in bacteria, all examined thus far function inefficiently in eukaryotes, where their ribozyme activity is limited by low Mg2+ concentrations, and intron-containing transcripts are subject to nonsense-mediated decay (NMD) and translational repression. Here, by using RNA polymerase II to express a humanized group II intron reverse transcriptase and T7 RNA polymerase to express intron transcripts resistant to NMD, we find that simply supplementing culture medium with Mg2+ induces the Lactococcus lactis Ll.LtrB intron to retrohome into plasmid and chromosomal sites, the latter at frequencies up to ~0.1%, in viable HEK-293 cells. Surprisingly, under these conditions, the Ll.LtrB intron reverse transcriptase is required for retrohoming but not for RNA splicing as in bacteria. By using a genetic assay for in vivo selections combined with deep sequencing, we identified intron RNA mutations that enhance retrohoming in human cells, but <4-fold and not without added Mg2+. Further, the selected mutations lie outside the ribozyme catalytic core, which appears not readily modified to function efficiently at low Mg2+ concentrations. Our results reveal differences between group II intron retrohoming in human cells and bacteria and suggest constraints on critical nucleotide residues of the ribozyme core that limit how much group II intron retrohoming in eukaryotes can be enhanced. These findings have implications for group II intron use for gene targeting in eukaryotes and suggest how differences in intracellular Mg2+ concentrations between bacteria and eukarya may have impacted the evolution of introns and gene expression mechanisms.

A system for addressing incidental findings in neuroimaging research.

When healthy subjects undergo brain imaging, incidental findings are not rare. The optimal response to such findings has been the focus of considerable discussion. The current report describes the operations and results of a system that provides a review of incidental findings by an appropriate medical professional. A web-based system was created whereby investigators performing brain MRI scans on healthy subjects could refer images with suspected concerns to a board certified radiologist who had a Certificate of Added Qualification in Neuroradiology. The specific details of this system are described. Among 27 scans suspected by an investigator of having a significant finding, all but one were referred by a researcher with a PhD. The most common concerns described by these investigators were for the possible presence of a cyst or of enlarged ventricles. The most common findings reported by the radiologist were Virchow-Robin spaces and cysts. Findings were generally of low clinical significance, with 1 major exception. Identifying the optimal response to incidental findings in neuroimaging research remains a challenge. The current report describes a system for providing expert assistance and so addresses these issues in the setting of suspected incidental findings. To our knowledge the current system is the first to provide a specific means for evaluation of incidental findings in neuroimaging research.

Assessment of Ambient Air Toxics and Wood Smoke Pollution among Communities in Sacramento County.

Ambient air monitoring and phone survey data were collected in three environmental justice (EJ) and three non-EJ communities in Sacramento County during winter 2016-2017 to understand the differences in air toxics and in wood smoke pollution among communities. Concentrations of six hazardous air pollutants (HAPs) and black carbon (BC) from fossil fuel (BCff) were significantly higher at EJ communities versus non-EJ communities. BC from wood burning (BCwb) was significantly higher at non-EJ communities. Correlation analysis indicated that the six HAPs were predominantly from fossil fuel combustion sources, not from wood burning. The HAPs were moderately variable across sites (coefficient of divergence (COD) range of 0.07 for carbon tetrachloride to 0.28 for m- and p-xylenes), while BCff and BCwb were highly variable (COD values of 0.46 and 0.50). The BCwb was well correlated with levoglucosan (R2 of 0.68 to 0.95), indicating that BCwb was a robust indicator for wood burning. At the two permanent monitoring sites, wood burning comprised 29-39% of the fine particulate matter (PM2.5) on nights when PM2.5 concentrations were forecasted to be high. Phone survey data were consistent with study measurements; the only significant difference in the survey results among communities were that non-EJ residents burn with indoor devices more often than EJ residents.

Acute hemorrhagic edema of infancy: case reports and a review of the literature.

Acute hemorrhagic edema of infancy (AHEI) is an unusual form of leukocytoclastic vasculitis that affects children younger than 2 years and frequently is preceded by drug intake, vaccination, or a variety of infections. It is characterized by an abrupt onset of fever, purpuric lesions, and peripheral edema on the face and extremities that may be confused with other dermatoses. The course is benign with spontaneous resolution. We present 2 infants with AHEI and review the clinical manifestations, histology, and differential diagnosis.

Timing of surgery and bevacizumab therapy in neurosurgical patients with recurrent high grade glioma.

Malignant gliomas continue to have a dismal prognosis despite all available treatments and advances made in understanding molecular mechanisms and signaling pathways. Conventional treatments, such as surgery, chemotherapy and radiation, have been used with limited success. Bevacizumab is a recently described molecule, which inhibits endothelial proliferation and prevents formation of new blood vessels in tumor. However, this treatment confers increased hemorrhage risk and impairs wound healing. Therefore, the timing of surgery for patients receiving bevacizumab, who are in need of surgery, is critical. We performed a literature review to establish the appropriate timing between the cessation of bevacizumab therapy and surgical intervention. Our literature review indicated that the optimum time between cessation of bevacizumab therapy and surgery was 4 weeks. The timing for re-initiation of bevacizumab post-surgery was at least 2 weeks. The duration of preoperative cessation of bevacizumab treatment is critical in preventing life threatening surgical complications. The interval between the surgery and re-initiation of bevacizumab can be shortened. However, more studies are needed to ascertain the exact timing of preoperative and postoperative therapy.

Antivascular endothelial growth factor antibody for treatment of glioblastoma multiforme.

Despite aggressive investigation, glioblastoma multiforme (GBM) remains one of the deadliest cancers, with low progression-free survival and high one-year mortality. Current first-line therapy includes surgery with adjuvant radiation therapy and cytotoxic chemotherapy, but virtually all tumors recur. Given the highly vascular nature of GBM and its high expression of vascular endothelial growth factor and other angiogenic factors, recent investigation has turned to bevacizumab, an antivascular endothelial growth factor monoclonal antibody, for treatment of recurrent GBM. Phase 2 studies demonstrated the efficacy and safety of bevacizumab therapy for recurrent GBM, which led to its approval by the US Food and Drug Administration in 2009 for use in recurrent GBM. Since then, several new Phase 2 studies and retrospective series have demonstrated that bevacizumab significantly increased six-month progression-free survival in patients with recurrent GBM and may do so in new-onset GBM. The objective of this review is to provide a collective resource for these materials, highlighting the efficacy and safety of bevacizumab and calling for increased investigation toward its optimal application in the management of high-grade glioma.

Use of the extended parallel processing model to evaluate culturally relevant kernicterus messages.

INTRODUCTION: Kernicterus is a serious but easily preventable disease in newborns that is not well-known even by some health care professionals. This study evaluated a parent guide and poster on kernicterus awareness and prevention generated by the Centers for Disease Control and Prevention. The extended parallel processing model was used as a framework for creating the interview protocol and analyzing the results. METHOD: In-depth interviews were conducted with four parents and six health care personnel of different ethnicities to evaluate the materials. Content for the parent guide and poster was held constant, but photos were varied according to the ethnicity of the baby (white, African American, or Hispanic) and the language in which the interviews were conducted (English and Spanish). RESULTS: The parent guide was evaluated positively, but reactions to the poster were varied. The consensus was that the poster drew more attention than the pocket guide but lacked sufficient information about what jaundice is or how to treat it, while the pocket guide provided information, especially with regard to efficacy. The extended parallel processing model claims that when efficacy is equal to or higher than perceived threat, respondents should engage in recommended responses, which was the general finding from these interviews. DISCUSSION: Recommendations for improvements of the materials are presented. The focus on different ethnicities in the materials was perceived as unnecessary and potentially counter-productive. Both parents and health care professionals mentioned the lack of information regarding treatment. Providing information on the length and effectiveness of treatment for jaundice and kernicterus might increase efficacy in averting the threat in both conditions.

Strength: a relevant link to functional performance in the neurodegenerative disease of adrenomyeloneuropathy.

BACKGROUND: With progressive abnormalities in leg strength, tone, and sensation, adrenomyeloneuropathy (AMN) is a differential diagnosis for multiple sclerosis and hereditary spastic paraparesis. AMN pathology has been linked to weakness, making it a relevant model to evaluate the relationship between neurodegeneration and disability. Quantifying symptom severity in AMN is essential for treatment development in rehabilitative management. OBJECTIVE: To identify deficits in body functions, activity, and participation of people with AMN and provide a practical framework for evaluating the severity of disability. METHODS: Cohort analysis of 142 participants with AMN. MEASURES: of body functions (leg strength, vibration sensation, range of motion, and spasticity), activity (walk velocity, standing balance, Timed Up and Go, and Sit-to-Stand Time), and participation (6-Minute Walk) are evaluated. Regression analyses identify relationships between the measures. A staging framework (mild, moderate, and severe) reflects the continuum of disability. Finally, an analysis of variance/Kruskal-Wallis was used for between-stage and sex differences among the variables. RESULTS: Strength is the strongest correlate for the 5 measures of activity and participation. Staging based on weakness distinguishes 3 levels of severity along a continuum of disability. Differences between the sexes are more prevalent earlier in the continuum but show equally severe deficits in the last stage. CONCLUSIONS: In AMN, staging based on degrees of weakness provides a practical means to characterize the severity of common deficits in body functions as well as activity and participation at each stage, to direct the evaluation. Such information could help clinicians develop more effective rehabilitative techniques.

Low concentrations of resveratrol inhibit Wnt signal throughput in colon-derived cells: implications for colon cancer prevention.

Resveratrol is a bioflavonoid which is known to inhibit cell proliferation and induce apoptosis in cancer cell lines at concentrations above 50 muM. It also has colon cancer prevention activity in mouse models and possibly in humans. We have examined the effects of low concentrations of resveratrol on a specific signaling pathway, the Wnt pathway, which is activated in over 85% of sporadic colon cancers. Two colon cancer (HT29 and RKO) and one normal mucosa-derived (NCM460) cell lines were utilized. Cell proliferation was not affected by resveratrol at < or =40 microM for HT29 and NCM460 and <20 microM for RKO though Wnt signal throughput, as measured by a reporter construct, was reduced in RKO and NCM460 at concentrations as low as 10 microM (p < 0.001). This effect was most easily appreciated following Wnt pathway stimulation with Wnt3a conditioned medium and LEF1 or LEF1/beta-catenin transfection. Resveratrol did not inhibit Wnt throughput in mutationally activated HT29. Low concentrations of resveratrol significantly decreased the amount and proportion of beta-catenin in the nucleus in RKO (p = 0.002) and reduced the expression of lgs and pygoI, regulators of beta-catenin localization, in all cells lines. Thus, at low concentrations, in the absence of effects on cell proliferation, resveratrol significantly inhibits Wnt signaling in colon-derived cells which do not have a basally activated Wnt pathway. This inhibitory effect may be due in part to regulation of intracellular beta-catenin localization.