Catalogue Search | MBRL
Are you sure you want to remove the book from the shelf?
{{itemTitle}}
21,566
result(s) for
"Adams, John S."
Sort by:
John Adams : revolutionary writings 1755-1775
\"... includes the complete newspaper exchange between Novanglus (Adams) and Massachusettensis (loyalist Daniel Leonard), as well as extensive diary excerpts and characteristically frank personal letters\"--Jacket.
BOOK
Unexpected actions of vitamin D: new perspectives on the regulation of innate and adaptive immunity
Beyond the classical effects of vitamin D on bone and calcium homeostasis, nonclassical effects in cancer and cardiovascular disease are emerging. This article details another important nonclassical role for vitamin D in regulating both innate and adaptive immunity, and how this can become compromised by vitamin D insufficiency.
Knowledge about the ability of vitamin D to function outside its established role in skeletal homeostasis is not a new phenomenon. Nonclassical immunomodulatory and antiproliferative responses triggered by active 1,25-dihydroxyvitamin D were first reported more than a quarter of a century ago. It is only in recent years, however, that there has been a significant improvement in our understanding of how these nonclassical effects of vitamin D can influence the pathophysiology and possible prevention of human disease. Three particular strands of evidence have been prominent: firstly, population studies have revised our interpretation of normal vitamin D status in humans, suggesting, in turn, that vitamin D insufficiency is a clinical problem of global proportions; secondly, epidemiology has linked vitamin D status with disease susceptibility and/or mortality; and, thirdly, expression of the machinery required to synthesize 1,25-dihydroxyvitamin D in normal human tissue seems to be much more widespread than originally thought. Collectively, these observations suggest that nonclassical metabolism and response to vitamin D might have a significant role in human physiology beyond skeletal and calcium homeostasis. Specific examples of this will be detailed in the current Review, with particular emphasis on the immunomodulatory properties of vitamin D.
Key Points
Nonclassical effects of vitamin D have been recognized for many years, but it is only recently that these have been accepted as a potentially significant component of vitamin D physiology
Immune cells such as macrophages contain all of the machinery required to synthesize and respond to active vitamin D, 1,25-dihydroxyvitamin D, and these functions are enhanced by challenge to the immune system
1,25-Dihydroxyvitamin D stimulates innate (macrophage) immunity by enhancing bacterial killing but it also modulates adaptive (lymphocyte) immunity to minimize inflammation and autoimmune disease
Vitamin D insufficiency is now a global health issue—even in developed countries
Vitamin D insufficiency is associated with compromised immunity, leading to increased infectious diseases such as tuberculosis, and increased susceptibility to autoimmune diseases such as type 1 diabetes
Journal Article
Absolute Green Lantern/Green Arrow
\"This stunning Absolute Edition of Green Lantern/Green Arrow collect the early 1970s, featuring classic team-ups written by Dennis O'Neil with art by Neal Adams! In these stories, Green Lantern Hal Jordan continued his usual cosmic-spanning adventures, as he used his amazing Power Ring to police Sector 2814 against universe-threatening menaces. Meanwhile, on Earth, Oliver Queen, the archer known as Green Arrow, was confronting menaces of a different kind: racism, poverty, drugs, and other social ills! This Absolute Edition will include additional script and character development pages as well as character sketches\"-- Provided by publisher.
Book
Vitamin D metabolites and the gut microbiome in older men
The vitamin D receptor is highly expressed in the gastrointestinal tract where it transacts gene expression. With current limited understanding of the interactions between the gut microbiome and vitamin D, we conduct a cross-sectional analysis of 567 older men quantifying serum vitamin D metabolites using LC-MSMS and defining stool sub-Operational Taxonomic Units from16S ribosomal RNA gene sequencing data. Faith’s Phylogenetic Diversity and non-redundant covariate analyses reveal that the serum 1,25(OH)
2
D level explains 5% of variance in α-diversity. In β-diversity analyses using unweighted UniFrac, 1,25(OH)
2
D is the strongest factor assessed, explaining 2% of variance. Random forest analyses identify 12 taxa, 11 in the phylum Firmicutes, eight of which are positively associated with either 1,25(OH)
2
D and/or the hormone-to-prohormone [1,25(OH)
2
D/25(OH)D] “activation ratio.” Men with higher levels of 1,25(OH)
2
D and higher activation ratios, but not 25(OH)D itself, are more likely to possess butyrate producing bacteria that are associated with better gut microbial health.
Here, the authors investigate associations of vitamin D metabolites with gut microbiome in a cross-sectional analysis of 567 elderly men enrolled in the Osteoporotic Fractures in Men (MrOS) Study and find larger alpha-diversity correlates with high 1,25(OH)2D and high 24,25(OH)2D and higher ratios of activation and catabolism.
Journal Article
Type I Interferon Suppresses Type II Interferon—Triggered Human Anti-Mycobacterial Responses
Type I interferons (IFN-α and IFN-β) are important for protection against many viral infections, whereas type II interferon (IFN-γ) is essential for host defense against some bacterial and parasitic pathogens. Study of IFN responses in human leprosy revealed an inverse correlation between IFN-β and IFN-γ gene expression programs. IFN-γ and its downstream vitamin D—dependent antimicrobial genes were preferentially expressed in self-healing tuberculoid lesions and mediated antimicrobial activity against the pathogen Mycobacterium leprae in vitro. In contrast, IFN-β and its downstream genes, including interleukin-10 (IL-10), were induced in monocytes by M. leprae in vitro and preferentially expressed in disseminated and progressive lepromatous lesions. The IFN-γ—induced macrophage vitamin D—dependent antimicrobial peptide response was inhibited by IFN-β and by IL-10, suggesting that the differential production of IFNs contributes to protection versus pathogenesis in some human bacterial infections.
Journal Article
A Mouse Model of Post-Arthroplasty Staphylococcus aureus Joint Infection to Evaluate In Vivo the Efficacy of Antimicrobial Implant Coatings
Post-arthroplasty infections represent a devastating complication of total joint replacement surgery, resulting in multiple reoperations, prolonged antibiotic use, extended disability and worse clinical outcomes. As the number of arthroplasties in the U.S. will exceed 3.8 million surgeries per year by 2030, the number of post-arthroplasty infections is projected to increase to over 266,000 infections annually. The treatment of these infections will exhaust healthcare resources and dramatically increase medical costs.
To evaluate novel preventative therapeutic strategies against post-arthroplasty infections, a mouse model was developed in which a bioluminescent Staphylococcus aureus strain was inoculated into a knee joint containing an orthopaedic implant and advanced in vivo imaging was used to measure the bacterial burden in real-time. Mice inoculated with 5x10(3) and 5x10(4) CFUs developed increased bacterial counts with marked swelling of the affected leg, consistent with an acute joint infection. In contrast, mice inoculated with 5x10(2) CFUs developed a low-grade infection, resembling a more chronic infection. Ex vivo bacterial counts highly correlated with in vivo bioluminescence signals and EGFP-neutrophil fluorescence of LysEGFP mice was used to measure the infection-induced inflammation. Furthermore, biofilm formation on the implants was visualized at 7 and 14 postoperative days by variable-pressure scanning electron microscopy (VP-SEM). Using this model, a minocycline/rifampin-impregnated bioresorbable polymer implant coating was effective in reducing the infection, decreasing inflammation and preventing biofilm formation.
Taken together, this mouse model may represent an alternative pre-clinical screening tool to evaluate novel in vivo therapeutic strategies before studies in larger animals and in human subjects. Furthermore, the antibiotic-polymer implant coating evaluated in this study was clinically effective, suggesting the potential for this strategy as a therapeutic intervention to combat post-arthroplasty infections.
Journal Article
T-cell cytokines differentially control human monocyte antimicrobial responses by regulating vitamin D metabolism
We investigated the mechanisms by which T-cell cytokines are able to influence the Toll-like receptor (TLR)-induced, vitamin D-dependent antimicrobial pathway in human monocytes. T-cell cytokines differentially influenced TLR2/1-induced expression of the antimicrobial peptides cathelicidin and DEFB4, being up-regulated by IFN-γ, down-regulated by IL-4, and unaffected by IL-17. The Th1 cytokine IFN-γ up-regulated TLR2/1 induction of 25-hydroxyvitamin D-1α-hydroxylase (i.e., CYP27B1), leading to enhanced bioconversion of 25-hydroxyvitamin D₃ (25D₃) to its active metabolite 1,25D₃. In contrast, the Th2 cytokine IL-4, by itself and in combination with the TLR2/1 ligand, induced catabolism of 25D₃ to the inactive metabolite 24,25D₃, and was dependent on expression of vitamin D-24-hydroxylase (i.e., CYP24A1). Therefore, the ability of T-cell cytokines to differentially control monocyte vitamin D metabolism represents a mechanism by which cell-mediated immune responses can regulate innate immune mechanisms to defend against microbial pathogens.
Journal Article
Vitamin D Binding Protein and Monocyte Response to 25-Hydroxyvitamin D and 1,25-Dihydroxyvitamin D: Analysis by Mathematical Modeling
Vitamin D binding protein (DBP) plays a key role in the bioavailability of active 1,25-dihydroxyvitamin D (1,25(OH)(2)D) and its precursor 25-hydroxyvitamin D (25OHD), but accurate analysis of DBP-bound and free 25OHD and 1,25(OH)(2)D is difficult. To address this, two new mathematical models were developed to estimate: 1) serum levels of free 25OHD/1,25(OH)(2)D based on DBP concentration and genotype; 2) the impact of DBP on the biological activity of 25OHD/1,25(OH)(2)D in vivo. The initial extracellular steady state (eSS) model predicted that 50 nM 25OHD and 100 pM 1,25(OH)(2)D), <0.1% 25OHD and <1.5% 1,25(OH)(2)D are 'free' in vivo. However, for any given concentration of total 25OHD, levels of free 25OHD are higher for low affinity versus high affinity forms of DBP. The eSS model was then combined with an intracellular (iSS) model that incorporated conversion of 25OHD to 1,25(OH)(2)D via the enzyme CYP27B1, as well as binding of 1,25(OH)(2)D to the vitamin D receptor (VDR). The iSS model was optimized to 25OHD/1,25(OH)(2)D-mediated in vitro dose-responsive induction of the vitamin D target gene cathelicidin (CAMP) in human monocytes. The iSS model was then used to predict vitamin D activity in vivo (100% serum). The predicted induction of CAMP in vivo was minimal at basal settings but increased with enhanced expression of VDR (5-fold) and CYP27B1 (10-fold). Consistent with the eSS model, the iSS model predicted stronger responses to 25OHD for low affinity forms of DBP. Finally, the iSS model was used to compare the efficiency of endogenously synthesized versus exogenously added 1,25(OH)(2)D. Data strongly support the endogenous model as the most viable mode for CAMP induction by vitamin D in vivo. These novel mathematical models underline the importance of DBP as a determinant of vitamin D 'status' in vivo, with future implications for clinical studies of vitamin D status and supplementation.
Journal Article
Role of Assay Type in Determining Free 25-Hydroxyvitamin D Levels in Diverse Populations
The choice of a vitamin D–binding protein assay is key in calculating free 25-hydroxyvitamin D levels. The results of this analysis support the use of total 25-hydroxyvitamin D as a marker of vitamin D status, regardless of race or GC genotype.
To the Editor:
It is unclear whether circulating free or bioavailable 25-hydroxyvitamin D is a better marker of vitamin D status than is total 25-hydroxyvitamin D, especially in racially diverse populations. Until recently, the only method to compare the levels was to estimate the level of free or bioavailable 25-hydroxyvitamin D from total 25-hydroxyvitamin D, vitamin D–binding protein (also known as gc-globulin, encoded by the
GC
gene), and albumin, with or without the
GC
genotype. Powe et al. reported that levels of vitamin D–binding protein, as measured on a monoclonal enzyme-linked immunosorbent assay (ELISA, R&D Systems), were lower in black . . .
Journal Article
NELL-1 in the treatment of osteoporotic bone loss
NELL-1 is a secreted, osteoinductive protein whose expression rheostatically controls skeletal ossification. Overexpression of NELL-1 results in craniosynostosis in humans and mice, whereas lack of
Nell-1
expression is associated with skeletal undermineralization. Here we show that
Nell-1
-haploinsufficient mice have normal skeletal development but undergo age-related osteoporosis, characterized by a reduction in osteoblast:osteoclast (OB:OC) ratio and increased bone fragility. Recombinant NELL-1 binds to integrin β1 and consequently induces Wnt/β-catenin signalling, associated with increased OB differentiation and inhibition of OC-directed bone resorption. Systemic delivery of NELL-1 to mice with gonadectomy-induced osteoporosis results in improved bone mineral density. When extended to a large animal model, local delivery of NELL-1 to osteoporotic sheep spine leads to significant increase in bone formation. Altogether, these findings suggest that NELL-1 deficiency plays a role in osteoporosis and demonstrate the potential utility of NELL-1 as a combination anabolic/antiosteoclastic therapeutic for bone loss.
The growth factor NELL-1 induces bone formation during development, but its role in osteoporosis is unknown. This study shows that NELL-1 binding to integrin ß1 induces Wnt/ß-catenin signalling in the bone and restores bone mineral density in osteoporotic mice and sheep, suggesting the therapeutic potential of NELL-1 for the treatment of bone loss.
Journal Article