A launch vector for the production of vaccine antigens in plants

Historically, most vaccines have been based on killed or live‐attenuated infectious agents. Although very successful at immunizing populations against disease, both approaches raise safety concerns and often have limited production capacity. This has resulted in increased emphasis on the development of subunit vaccines. Several recombinant systems have been considered for subunit vaccine manufacture, including plants, which offer advantages both in cost and in scale of production. We have developed a plant expression system utilizing a ‘launch vector’, which combines the advantageous features of standard agrobacterial binary plasmids and plant viral vectors, to achieve high‐level target antigen expression in plants. As an additional feature, to aid in target expression, stability and purification, we have engineered a thermostable carrier molecule to which antigens are fused. We have applied this launch vector/carrier system to engineer and express target antigens from various pathogens, including, influenza A/Vietnam/04 (H5N1) virus.     

A proof-of-concept study of short-cycle intermittent antiretroviral therapy with a once-daily regimen of didanosine, lamivudine, and efavirenz for the treatment of chronic HIV infection

BACKGROUND: We previously demonstrated that short-cycle structured intermittent therapy (SIT; 7 days without therapy followed by 7 days with antiretroviral therapy [ART]) with a ritonavir-boosted, indinavir-based, twice-daily regimen maintained suppression of plasma HIV viremia while reducing serum levels of lipids. Adherence to such a regimen may be problematic for certain patients. METHODS: Eight patients with a history of receiving combination ART that maintained suppression of plasma HIV RNA to <50 copies/mL received a once-daily SIT regimen of didanosine, lamivudine, and efavirenz. RESULTS: For 7 patients, suppression of plasma HIV RNA to <50 copies/mL was maintained for 60-84 weeks. Four patients with adequate samples had no evidence for an increase in plasma viremia for up to 72 weeks, by use of an assay with a limit of detection of <1 copy/mL. The lack of rebound viremia may be the result of the persistence of efavirenz in plasma on day 7 of the no-therapy period, as was detected in 7 of 7 patients. There was no significant change in CD4(+) T cell counts or serum hepatic transaminase or lipid levels. CONCLUSION: A once-daily short-cycle SIT regimen maintained suppression of plasma HIV RNA while preserving CD4(+) T cell counts. Such a regimen may have importance in resource-limited settings where the monetary cost of continuous ART is prohibitive.     

Synthesis and Biological Evaluations of Electrophilic Steroids Inspired by the Taccalonolides

Natural products have served as inspirational scaffolds for the design and synthesis of novel antineoplastic agents. Here we present our preliminary efforts on the synthesis and biological evaluation of a new class of electrophilic steroids inspired by the naturally occurring taccalonolides. We demonstrate that these simplified analogs exhibit highly persistent antiproliferative properties similar to the taccalonolides and retain activity against resistant cancer cell lines that warrants further preclinical development.     

Randomized,Placebo-Controlled Trial of Targeting Neuroinflammation with Ibudilast to Treat Methamphetamine Use Disorder

Journal of Neuroimmune Pharmacology - Methamphetamine (MA) triggers neuroinflammation and medications that counteract MA-induced neuroinflammation may reduce MA-induced neurodegeneration and...     

Regulation of hematopoietic cell signaling by SHIP-1 inositol phosphatase: growth factors and beyond

SHIP-1 is a hematopoietic-specific inositol phosphatase activated downstream of a multitude of receptors including those for growth factors, cytokines, antigen, immunoglobulin and toll-like receptor agonists where it exerts inhibitory control. While it is constitutively expressed in all immune cells, SHIP-1 expression is negatively regulated by the inflammatory and oncogenic micro-RNA miR-155. Knockout mouse studies have shown the importance of SHIP-1 in various immune cell subsets and have revealed a range of immune-mediated pathologies that are engendered due to loss of SHIP-1’s regulatory activity, impelling investigations into the role of SHIP-1 in human disease. In this review, we provide an overview of the literature relating to the role of SHIP-1 in hematopoietic cell signaling and function, we summarize recent reports that highlight the dysregulation of the SHIP-1 pathway in cancers, autoimmune disorders and inflammatory diseases, and lastly we discuss the importance of SHIP-1 in restraining myeloid growth factor signaling.     

Human Sarcomas Are Mosaic for Telomerase-Dependent and Telomerase-Independent Telomere Maintenance Mechanisms: Implications for Telomere-Based Therapies

Telomere shortening necessitates that tumor cells activate a telomere maintenance mechanism (TMM) to support immortalization. Although most tumor cells activate expression of the enzyme telomerase, some cells elongate telomeres in a telomerase-independent manner, termed alternative lengthening of telomeres (ALT). Previous studies have evaluated the presence of telomerase or ALT mechanisms or both in a variety of tumor types. Our studies also show that TMMs are not mutually exclusive in some tumors. In contrast, our IHC analyses of human sarcomas identified a subset of tumors with some cells containing ALT-associated PML bodies, a hallmark of ALT, and separate cells expressing telomerase in the same tumor. By using a second set of human osteosarcomas, we merged IHC and biochemical analyses to characterize more fully the tumor TMM. The IHC data reveal the presence of both telomerase- and ALT-positive tumor cells in samples that demonstrate characteristics of both telomerase and ALT in biochemical assays. These assays, which measure telomere length and telomerase activity of tumor extracts, are conventionally used to classify tumor TMM. Our results suggest that TMM is not a single or perhaps static characteristic of some tumors and that TMM heterogeneity should be considered in tumor stratification. Furthermore, clinical interest in telomere-based therapies may necessitate accurate characterization of tumor TMM before treatment to maximize therapeutic efficacy.Activation of a telomere maintenance mechanism (TMM) is critical for tumor cell immortalization and cancer progression because telomeres shorten with each round of cellular division. Cells can use two known TMMs: catalytic activity of the enzyme telomerase or a telomerase-independent, recombination-based pathway termed alternative lengthening of telomeres (ALT). In contrast to cells with active telomerase, cells that use ALT are characterized by long, heterogeneous telomere lengths, ALT-associated PML bodies (APBs), and extrachromosomal telomeric repeats. Several studies have evaluated TMMs in human tumors^1,2 and demonstrated that ALT is overrepresented in mesenchymal tumors,^2–12 perhaps reflective of a lack of detectable telomerase expression in mesenchymal stem cells.¹³ More specifically, almost 60% of osteosarcomas exhibit ALT characteristics,^3–6 the highest incidence of any tumor yet evaluated. In contrast, epithelial tumors more often express telomerase,^1,2 suggesting there may be cell-specific preferences for TMM.Studies have demonstrated that either type of TMM can occur within the same cell, but only with experimental manipulation. Exogenous expression of functional telomerase within some ALT cell lines results in telomerase-mediated elongation of short telomeres, although cells still retain ALT characteristics^14–16; studies in other ALT cell lines have shown that telomerase expression inhibits ALT characteristics.¹⁷ Fusion experiments of telomerase-expressing and ALT cells have shown that the mechanisms governing telomere maintenance are complex. Some telomerase-expressing cells contain ALT inhibitors other than telomerase itself, because only some hybrid cells suppress ALT markers and maintain telomeres exclusively with telomerase.¹⁶ Other experiments with hybrid cells demonstrate suppression of telomerase activity and maintenance of telomeres by ALT, suggesting that some ALT cells contain telomerase inhibitors.¹⁸ Similar observations have not been made in vivo.Most tumors exhibit characteristics of one TMM. However, most published studies that have classified human tumors have also identified a subset of tumors not definitively ALT or telomerase positive.^{3–6,9–12,19–23} These tumors display ambiguous characteristics regarding telomere length, telomerase activity, or the presence of APBs. Some tumors have long, heterogeneous telomere lengths, suggestive of ALT, but exhibit telomerase activity; this ambiguity confounds accurate TMM characterization. Furthermore, although previous studies have identified tumors exhibiting both telomerase activity and the presence of APBs,^10,11 suggesting that both telomerase and ALT cells are present in the sample, it has not been demonstrated whether these results indicate separate cell populations, infiltrating normal cells/normal surrounding tissue, or the presence of multiple TMMs in one cell. Therefore, we asked whether human sarcomas could demonstrate mosaicism for TMM by evaluating tumors at a cellular level.     

Effect of the COVID-19 pandemic on CT scans ordered from the emergency department for abdominal complaints

Emergency Radiology - The COVID-19 pandemic has affected healthcare systems and patients alike across the USA. We seek to elucidate changes in abdominal imaging ordered from the emergency...     

Time course of the unmasked attentional blink

The Attentional Blink (AB) usually refers to the impaired report of a second target (T2) if it appears within 200–500 ms after a first target within a rapid sequence of distractors. The present study focused on a less studied AB variant known as the unmasked AB, where T2 is the last item of the sequence and T2 report is unaffected. This aspect of the unmasked AB holds promise for an experimental paradigm in which measures of on‐going event‐related processing are unconfounded by differences in late‐stage processing. To fully characterize the unmasked AB paradigm, we used a randomization statistics approach to comprehensively examine the electroencephalographic signature of the unmasked AB. We examined the unmasked AB with auditory and visual T2s—participants attended to either the auditory or visual information within a sequence of paired auditory‐visual stimuli, and reported targets within the attended modality stream while ignoring the other. As predicted, T2 report was unaffected by the unmasked AB. The visual AB was associated with delayed but intact N2 and P3 components, and a suppressed N1. We suggest that this N1 is linked to auditory processing of the distractor stream, and reflects the cognitive system prioritizing the processing of visual targets over auditory distractors in response to AB‐related processing load. The auditory AB only indicated a delayed but intact P3. Collectively, these findings support the view that the AB limits the entry of information into consciousness via a late‐stage modal bottleneck, and suggest an ongoing compensatory response at early latencies.