47 research outputs found

    Molecular Characterization of a Novel Intracellular ADP-Ribosyl Cyclase

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    Background. ADP-ribosyl cyclases are remarkable enzymes capable of catalyzing multiple reactions including the synthesis of the novel and potent intracellular calcium mobilizing messengers, cyclic ADP-ribose and NAADP. Not all ADP-ribosyl cyclases however have been characterized at the molecular level. Moreover, those that have are located predominately at the outer cell surface and thus away from their cytosolic substrates. Methodology/Principal Findings. Here we report the molecular cloning of a novel expanded family of ADP-ribosyl cyclases from the sea urchin, an extensively used model organism for the study of inositol trisphosphate-independent calcium mobilization. We provide evidence that one of the isoforms (SpARC1) is a soluble protein that is targeted exclusively to the endoplasmic reticulum lumen when heterologously expressed. Catalytic activity of the recombinant protein was readily demonstrable in crude cell homogenates, even under conditions where luminal continuity was maintained. Conclusions/Significance. Our data reveal a new intracellular location for ADP-ribosyl cyclases and suggest that production of calcium mobilizing messengers may be compartmentalized

    The Yeast Nuclear Pore Complex and Transport Through It

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    Exchange of macromolecules between the nucleus and cytoplasm is a key regulatory event in the expression of a cell’s genome. This exchange requires a dedicated transport system: (1) nuclear pore complexes (NPCs), embedded in the nuclear envelope and composed of proteins termed nucleoporins (or “Nups”), and (2) nuclear transport factors that recognize the cargoes to be transported and ferry them across the NPCs. This transport is regulated at multiple levels, and the NPC itself also plays a key regulatory role in gene expression by influencing nuclear architecture and acting as a point of control for various nuclear processes. Here we summarize how the yeast Saccharomyces has been used extensively as a model system to understand the fundamental and highly conserved features of this transport system, revealing the structure and function of the NPC; the NPC’s role in the regulation of gene expression; and the interactions of transport factors with their cargoes, regulatory factors, and specific nucleoporins

    A case of nocardiosis in a patient with ulcerative colitis on chronic corticosteroids, infliximab, and upadacitinib

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    Key Clinical Message Immunosuppression, malnutrition, and underlying infection can unmask obscure infections which can be challenging to identify. Early diagnosis and treatment of infections in immunosuppressed patients are essential due to high morbidity and mortality. Abstract The immunosuppressive effects of treatment for ulcerative colitis (UC), including chronic corticosteroids, anti‐TNF agents, and JAK inhibitors, can impact the spread of latent or obscure infections. Clinicians should have a low threshold for pursuing aggressive diagnostic and therapeutic intervention in patients who show signs of clinical deterioration while on immunosuppressing medications. Our unique case highlights an immunosuppressed patient with UC who developed Nocardiosis after initiation of upadacitinib while hospitalized for concurrent UC flare and Clostridium difficile infection

    Regular and low-dose aspirin, other non-steroidal anti-inflammatory medications and prospective risk of HER2-defined breast cancer: the California Teachers Study

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    Abstract Background Regular users of aspirin may have reduced risk of breast cancer. Few studies have addressed whether risk reduction pertains to specific breast cancer subtypes defined jointly by hormone receptor (estrogen and progesterone receptor) and human epidermal growth factor receptor 2 (HER2) expression. This study assessed the prospective risk of breast cancer (overall and by subtype) according to use of aspirin and other non-steroidal anti-inflammatory medications (NSAIDs) in a cohort of female public school professionals in California. Methods In 1995 − 1996, participants in the California Teachers Study completed a baseline questionnaire on family history of cancer and other conditions, use of NSAIDs, menstrual and reproductive history, self-reported weight and height, living environment, diet, alcohol use, and physical activity. In 2005–2006, 57,164 participants provided some updated information, including use of NSAIDs and 1457 of these participants developed invasive breast cancer before January 2013. Multivariable Cox proportional hazards regression models provided hazard rate ratios (HRR) for the association between NSAID use and risk of invasive breast cancer as well as hormone receptor- and HER2-defined subtypes. Results Developing breast cancer was associated inversely with taking three or more tablets of low-dose aspirin per week (23% of participants). Among women reporting this exposure, the HRR was 0.84 (95% confidence interval (CI) 0.72–0.98) compared to those not taking NSAIDs and this was particularly evident in women with the hormone receptor-positive/HER2-negative subtype (HRR = 0.80, 95% CI 0.66–0.96). Use of three or more tablets of “other” NSAIDs was marginally associated with lower risk of breast cancer (HRR = 0.79, 95% CI 0.62–1.00). Other associations with NSAIDs were generally null. Conclusion Our observation of reduced risk of breast cancer, among participants who took three or more tablets of low-dose aspirin weekly, is consistent with other reports looking at aspirin without differentiation by dose. This is the first report to suggest that the reduction in risk occurs for low-dose aspirin and not for regular-dose aspirin and only among women with the hormone receptor-positive/HER2-negative subtype. This preliminary study builds on previous knowledge and further supports the need for formal cancer chemoprevention studies of low-dose aspirin

    De Novo Bone Induction by Recombinant Human Bone Morphogenetic Protein-2 (rhBMP-2) in Maxillary Sinus Floor Augmentation

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    This phase II study was designed to evaluate 2 concentrations of recombinant human bone morphogenetic protein-2 (rhBMP-2) for safety and efficacy in inducing adequate bone for endosseous dental implant in patients requiring staged maxillary sinus floor augmentation. Patients were treated with rhBMP-2 (via an absorbable collagen sponge [ACS]), at concentrations of 0.75 mg/mL (n = 18), 1.50 mg/mL (n = 17), or with bone graft (n = 13). Bone induction was assessed by alveolar ridge height, width, and density measurements from computed tomography scans obtained before and 4 months after treatment and 6 months post-functional loading of dental implants (density only). Mean increases in alveolar ridge height at 4 months after treatment were similar among the groups; 11.3 mm, 9.5 mm, and 10.2 mm, respectively, in the bone graft, 0.75 mg/mL, and 1.50 mg/mL rhBMP-2/ACS treatment groups. Mean increases in alveolar ridge width (buccal to lingual) at the crest of the ridge were statistically different among the treatment groups; 4.7 mm, 2.0 mm, and 2.0 mm, respectively, in the bone graft, 0.75 mg/mL, and 1.50 mg/mL treatment groups ( P ≤ .01 vs 0.75 mg/mL; P < .01 vs 1.50 mg/mL). At 4 months postoperative new bone density was statistically different among the treatment groups; 350 mg/cc, 84 mg/cc, and 134 mg/cc for the bone graft, 0.75 mg/mL, and 1.50 mg/mL rhBMP-2/ACS treatment groups, respectively ( P = .003 vs 0.75 mg/mL, P = .0137 vs 1.50 mg/mL, P = .0188; 1.50 mg/mL vs 0.75 mg/mL). Core bone biopsies obtained at the time of dental implant placement confirmed normal bone formation. The proportion of patients who received dental implants that were functionally loaded and remained functional at 36 months post-functional loading was 62%, 67%, and 76% in the bone graft, 0.75 mg/mL, and 1.50 mg/mL rhBMP-2/ACS treatment groups, respectively. This study is the first randomized controlled trial demonstrating de novo organ tissue growth in humans from a recombinant human protein. rhBMP-2/ACS safely induced adequate bone for the placement and functional loading of endosseous dental implants in patients requiring staged maxillary sinus floor augmentation
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