2D Synthesis Research Articles

Anti-inflammatory chromone alkaloids and glycoside from Dysoxylum binectariferum

Herein we report isolation of a new chromone alkaloid chrotacumine K (12) from fruits and a chromone glycoside schumaniofioside A (13) from leaves of Dysoxylum binectariferum Hook f. Schumaniofioside A is reported for the first time from Meliaceae family. Other known alkaloids isolated include rohitukine (1) and chrotacumine E (6). The structure of new alkaloid 12 was elucidated on the basis of extensive 1D and 2D NMR analysis, synthesis and chemical hydrolysis. Chemically, chrotacumine K (12) is a 3′-O-acetyl rohitukine which on chemical or enzymatic hydrolysis produces rohitukine. The new alkaloid 12 is also present in seeds and stem-barks of this plant. The glycoside schumaniofioside A (13) is present only in leaves, and in abundance (∼1% w/w of dried leaves). The isolated compounds and extracts were evaluated for in vitro effect on the proinflammatory cytokines (TNF-α and IL-6) in human monocytic THP-1 cells. The alkaloid 12 displayed potent inhibition (57%) of TNF-α at 0.3µM, and was non-toxic to THP-1 cells up to 40µM, indicating its excellent therapeutic window. Furthermore, a nitrobenzoyl ester analog 15e showed better inhibition of IL-6 than parent natural product chrotacumine K.

2D Pharmacophoric Design and Synthesis of Novel Pyrimidine Derivatives as Anticonvulsants

2D Pharmacophoric Design and Synthesis of Novel Pyrimidine Derivatives as Anticonvulsants

DENSA: An effective negative selection algorithm with flexible boundaries for self-space and dynamic number of detectors

The negative selection algorithm is an anomaly detection technique inspired by the self-nonself discrimination behavior observed in the Biological Immune System. The most controversial question of these algorithms is their poor performance on real world applications. To overcome such limitation this research work focuses on generating more efficient detectors through a more flexible boundary for self-patterns. Rather than applying conventional affinity measures, the detectors are generated benefiting from a Gaussian Mixture Model (GMM) fitted on normal space. From the GMM capabilities the algorithm is able to dynamically determine efficient subsets of detectors. In order to evaluate the efficiency and robustness of the proposed algorithm, different data sets have been examined as benchmark, including 2D synthesis data sets. Furthermore, for evaluating the capability and effectiveness of the proposed algorithm on real-world problems, it has been performed and tested for detecting anomalies in archaeological sites located in Lorestan, Iran. The experimental results prove how the proposed approach helps the negative selection algorithm to improve its detection capability, because the detectors can be efficiently distributed into the non-self space. It is important to note how this research work presents also a first analysis of the anomaly detection capabilities in the field of archaeology, introducing a novel application method, which can be efficiently used by the archaeologists for interpreting their growing amount of data and draw valuable conclusions about the historical past. Finally, in order to analyse the convergence and the running time of the proposed algorithm, a study has been conducted using the classical Time-To-Target plots, which present a standard graphical methodology for data analysis based on the comparisons between the empirical and theoretical distributions.

Recent progress in 2D or 3D N-doped graphene synthesis and the characterizations, properties, and modulations of N species

Nitrogen (N)-doped graphene (N-substituted or nitrogenated graphene) (NG) has become a new class of graphene material due to its modified properties such as the tunable work function, n-type semiconductivity, increasing biocompatibility, and, in particular, the synergistic function with various functional materials. However, the preparation of NG by a simple and effective method is still lacking. The modification of NG mainly depends on the N species and the N content. Thus, we focus on the recent progress in preparing methods of 2D NG and the respective key modulating parameters to modulate the N species and the N content. Furthermore, many effective charactering techniques are covered to accurately analyze the properties of N species, and the distribution and topography of N atoms. Also, we review the effect of N species on graphene, especially, the optical and electronic properties. Since constructing 3D structure is considered a promising strategy to prevent the restacking of 2D NG, the summary for preparing 3D NG is made on the basis of methodology of 2D NG. In a word, this review provides a reference for preparing 2D or 3D NG, modulating and characterizing N species, which are greatly contributed to the NG application.

Characterization of FGF23-Dependent Egr-1 Cistrome in the Mouse Renal Proximal Tubule.

Fibroblast growth factor 23 (FGF23) is a potent regulator of phosphate (Pi) and vitamin D homeostasis. The transcription factor, early growth response 1 (egr-1), is a biomarker for FGF23-induced activation of the ERK1/2 signaling pathway. We have shown that ERK1/2 signaling blockade suppresses renal egr-1 gene expression and prevents FGF23-induced hypophosphatemia and 1,25-dihydroxyvitamin D (1,25(OH)2D) suppression in mice. To test whether egr-1 itself mediates these renal actions of FGF23, we administered FGF23 to egr-1 -/- and wild-type (WT) mice. In WT mice, FGF23 induced hypophosphatemia and suppressed expression of the renal Na/Pi cotransporters, Npt2a and Npt2c. In FGF23-treated egr-1 -/- mice, hypophosphatemic response was greatly blunted and Na/Pi cotransporter expression was not suppressed. In contrast, FGF23 induced equivalent suppression of serum 1,25(OH)2D concentrations by suppressing renal cyp27b1 and stimulating cyp24a1 mRNA expression in both groups of mice. Thus, downstream of receptor binding and ERK1/2 signaling, we can distinguish the effector pathway that mediates FGF23-dependent inhibition of Pi transport from the pathway that mediates inhibition of 1,25(OH)2D synthesis in the kidney. Furthermore, we demonstrate that the hypophosphatemic effect of FGF23 is significantly blunted in Hyp/egr-1 -/- mice; specifically, serum Pi concentrations and renal Npt2a and Npt2c mRNA expression are significantly higher in Hyp/egr-1 -/- mice than in Hyp mice. We then characterized the egr-1 cistrome in the kidney using ChIP-sequencing and demonstrate recruitment of egr-1 to regulatory DNA elements in proximity to several genes involved in Pi transport. Thus, our data demonstrate that the effect of FGF23 on Pi homeostasis is mediated, at least in part, by activation of egr-1.

Vitamin D therapy in chronic kidney disease: back to the future?

Deficiency of 1,25(OH)2 vitamin D is inevitable in CKD, and is part of a cascade of bone and mineral abnormalities that result in secondary hyperparathyroidism. The widespread acceptance of calcitriol therapy as the treatment paradigm, has resulted in an overall neglect of vitamin D deficiency, as defined by low serum 25(OH)D levels Recent research has greatly enhanced our understanding of the disordered vitamin D metabolism seen in CKD. Furthermore vitamin D has been implicated in numerous disease states, beyond its traditional role in regulating bone and mineral metabolism. Low serum 25(OH)D levels have been linked to numerous adverse clinical outcomes in health and CKD. Additionally, the recognition of extra-renal, autocrine 1,25(OH)2D synthesis, present in many tissues, has refocused attention on the therapeutic potential of correcting low serum 25(OH)D levels. In this review we examine the physiology of disordered vitamin D metabolism in CKD, the clinical associations of low 25(OH)D levels in CKD, and discuss the rationale for vitamin D replacement in current clinical practice.

Tailoring Porphyrin (Nano)Structures

Many possibilities exist to modify the structure of porphyrins. These include variation of the central metal, N-substitution or modulation of the macrocyclic π-system. Recent years have seen a surge in π-annulated systems while a more established approach is the synthesis of nonplanar porphyrins via peripheral macrocycle interactions. Any of these strategies results in porphyrin systems with altered structure, conformation and physicochemical properties. What is lacking is true ‘conformational design’ of porphyrins, i.e., the use of the recent advances in organometallic chemistry in conjunction with structural studies to yield functional systems with predesigned conformations. Such an approach would aid development of new optical materials and catalysts.Similarly, an expanding body of studies on porphyrin nanomaterials on surfaces is beginning to reveal how surface/macrocycle interactions alter the chemical properties of porphyrins. Metallation and metal exchange reactions are possible and specific types of porphyrin nanostructures are now accessible via logical 2D synthesis on metal surfaces. Initial studies of porphyrin-graphene interactions indicate that a combination of tailor made porphyrins with specific macrocycle-surface interactions can yield functional nanomaterials.

The acid–ash hypothesis revisited: a reassessment of the impact of dietary acidity on bone

The acid-ash hypothesis states that when there are excess blood protons, bone is eroded to provide alkali to buffer the net acidity and maintain physiologic pH. There is concern that with the typical Western diet, we are permanently in a state of net endogenous acid production, which is gradually reducing bone. While it is clear that a high acid-producing diet generates increased urinary acid and calcium excretion, the effect of diet does not always have the expected results on BMD, fracture risk and markers of bone formation and resorption, suggesting that other factors are influencing the effect of acid/alkali loading on bone. High dietary protein, sodium and phosphorus intake, all of which are necessary for bone formation, were thought to be net acid forming and contribute to low BMD and fracture risk, but appear under certain conditions to be beneficial, with the effect of protein being driven by calcium repletion. Dietary salt can increase short-term markers of bone resorption but may also trigger 1,25(OH)2D synthesis to increase calcium absorption; with low calcium intake, salt intake may be inversely correlated with BMD but with high calcium intake, salt intake was positively correlated with BMD. With respect to the effect of phosphorus, the data are conflicting. Inclusion of an analysis of calcium intake may help to reconcile the contradictory results seen in many of the studies of bone. The acid-ash hypothesis could, therefore, be amended to state that with an acid-producing diet and low calcium intake, bone is eroded to provide alkali to buffer excess protons but where calcium intake is high the acid-producing diet may be protective.

FGF-23 Regulates CYP27B1 Transcription in the Kidney and in Extra-Renal Tissues

The mitochondrial enzyme 25-hydroxyvitamin D 1α-hydroxylase, which is encoded by the CYP27B1 gene, converts 25OHD to the biological active form of vitamin D, 1,25-dihydroxyvitamin D (1,25(OH)2D). Renal 1α-hydroxylase activity is the principal determinant of the circulating 1,25(OH)2D concentration and enzyme activity is tightly regulated by several factors. Fibroblast growth factor-23 (FGF-23) decreases serum 1,25(OH)2D concentrations by suppressing CYP27B1 mRNA abundance in mice. In extra-renal tissues, 1α-hydroxylase is responsible for local 1,25(OH)2D synthesis, which has important paracrine actions, but whether FGF-23 regulates CYP27B1 gene expression in extra-renal tissues is unknown. We sought to determine whether FGF-23 regulates CYP27B1 transcription in the kidney and whether extra-renal tissues are target sites for FGF-23-induced suppression of CYP27B1. In HEK293 cells transfected with the human CYP27B1 promoter, FGF-23 suppressed promoter activity by 70%, and the suppressive effect was blocked by CI-1040, a specific inhibitor of extracellular signal regulated kinase 1/2. To examine CYP27B1 transcriptional activity in vivo, we crossed fgf-23 null mice with mice bearing the CYP27B1 promoter-driven luciferase transgene (1α-Luc). In the kidney of FGF-23 null/1α-Luc mice, CYP27B1 promoter activity was increased by 3-fold compared to that in wild-type/1α-Luc mice. Intraperitoneal injection of FGF-23 suppressed renal CYP27B1 promoter activity and protein expression by 26% and 60% respectively, and the suppressive effect was blocked by PD0325901, an ERK1/2 inhibitor. These findings provide evidence that FGF-23 suppresses CYP27B1 transcription in the kidney. Furthermore, we demonstrate that in FGF-23 null/1α-Luc mice, CYP27B1 promoter activity and mRNA abundance are increased in several extra-renal sites. In the heart of FGF-23 null/1α-Luc mice, CYP27B1 promoter activity and mRNA were 2- and 5-fold higher, respectively, than in control mice. We also observed a 3- to 10-fold increase in CYP27B1 mRNA abundance in the lung, spleen, aorta and testis of FGF-23 null/1α-Luc mice. Thus, we have identified novel extra-renal target sites for FGF-23-mediated regulation of CYP27B1.

Take Another CYP: Confirming a Novel Mechanism for “Idiopathic” Hypercalcemia

Take Another CYP: Confirming a Novel Mechanism for “Idiopathic” Hypercalcemia

Seeded growth of two-dimensional dendritic gold nanostructures

We show that seeded growth can be applied to creating two-dimensional (2D) dendritic Au nanostructures on sample grids, which can be directly characterized by transmission electron microscopy (TEM). The 2D synthesis of highly consistent structures offers a novel mechanistic perspective on the aggregation of colloidal Au nanocrystals on a surface.

Design of 2D linear phase DFT modulated filter banks using bi-iterative second-order cone program

In this paper, the recent bi-iterative second-order cone program (BI-SOCP) to design one-dimensional (1D) DFT modulated filter banks is extended to the 2D case to design two-dimensional (2D) linear phase nonseparable DFT modulated filter banks. Some essential properties of 2D DFT modulated filter banks are presented and a permissibility of the configuration of filter banks is given. The design problem is formulated into a non-convex optimization, which minimizes the maximal amplitude of the transfer function distortion and aliasing transfer functions of the filter bank subject to predefined bounds on the stopband energy, the transition-band energy, and a passband flatness measure of the prototype filters (PFs). The optimization problem is solved by the BI-SOCP algorithm, where 2D linear phase analysis and synthesis PFs are alternately optimized via second-order cone programs (SOCPs). Numerical examples are included to show that the BI-SOCP can yield 2D linear phase nonseparable DFT modulated filter banks with good overall performance.

Parathyroid hormone fragments inhibit active hormone and hypocalcemia-induced 1,25(OH)2D synthesis

Carboxyl (C)-terminal fragments of parathyroid hormone (PTH) oppose the calcemic, phosphaturic, and bone-resorbing effects of active hormone. To study the action of these fragments on 1,25(OH)(2)D (1,25-dihydroxyvitamin D) synthesis, we infused parathyroidectomized rats with human or rat active 1-34 or 1-84 PTH at doses selected to produce similar calcemic responses. Human active PTH influenced neither phosphate nor 1,25(OH)(2)D concentrations. However, active 1-34 rat PTH decreased phosphate to the same level as vehicle-treated rats and increased 1,25(OH)(2)D to very high levels, whereas active 1-84 PTH decreased phosphate but maintained 1,25(OH)(2)D. As the latter effect could have been due to C-terminal fragment generation during its metabolic breakdown, we infused a mixture of rat C-terminal fragments alone or with rat 1-34. The C-terminal fragments decreased 1,25(OH)(2)D and prevented hypocalcemic-induced 1,25(OH)(2)D synthesis. When infused with active rat 1-34, they lowered the 1,25(OH)(2)D level to that seen with intact rat 1-84. The C-terminal fragments did not influence either basal or rat 1-34- or 1-84-induced CYP27B1 mRNA levels, suggesting that their inhibitory effects on 1,25(OH)(2)D synthesis appears to be post-transcriptional.

Continuous PTH and PTHrP Infusion Causes Suppression of Bone Formation and Discordant Effects on 1,25(OH)2Vitamin D

Osteoblast activity and plasma 1,25(OH)2 vitamin D are increased in HPT but suppressed in HHM. To model HPT and HHM, we directly compared multiday continuous infusions of PTH versus PTHrP in humans. Continuous infusion of both PTH and PTHrP results in marked and prolonged suppression of bone formation; renal 1,25(OH)2D synthesis was stimulated effectively by PTH but poorly by PTHrP. PTH and PTH-related protein (PTHrP) cause primary hyperparathyroidism (HPT) and humoral hypercalcemia of malignancy (HHM), respectively. Whereas HHM and HPT resemble one another in many respects, osteoblastic bone formation and plasma 1,25(OH)2 vitamin D are increased in HPT but reduced in HHM. We performed 2- to 4-day continuous infusions of escalating doses of PTH and PTHrP in 61 healthy young adults, comparing the effects on serum calcium and phosphorus, renal calcium and phosphorus handling, 1,25(OH)2 vitamin D, endogenous PTH(1-84) concentrations, and plasma IGF-1 and markers of bone turnover. PTH and PTHrP induced comparable effects on renal calcium and phosphorus handling, and both stimulated IGF-1 and bone resorption similarly. Surprisingly, PTH was consistently more calcemic, reflecting a selectively greater increase in renal 1,25(OH)2 vitamin D production by PTH. Equally surprisingly, continuous infusion of both peptides markedly, continuously, and equivalently suppressed bone formation. PTHrP and PTH produce markedly different effects on 1,25(OH)2 vitamin D homeostasis in humans, leading to different calcemic responses. Moreover, both peptides produce profound suppression of bone formation over multiple days, contrasting with events in HPT, but mimicking HHM. These findings underscore the facts that the mechanisms underlying the anabolic skeletal response to PTH and PTHrP in humans is poorly understood, as are the signal transduction mechanisms that link the renal PTH receptor to 1,25(OH)2 vitamin D synthesis. These studies emphasize that much remains to be learned regarding the normal regulation of vitamin D metabolism and bone formation in response to PTH and PTHrP in humans.

Regulation of 25-hydroxyvitamin D-1α-hydroxylase by epidermal growth factor in prostate cells

Accumulating data suggest that local production of 1α,25-dihydroxyvitamin D (1α,25(OH) 2D) could provide an important cell growth regulatory mechanism in an autocrine fashion in prostate cells. Previously, we demonstrated a differential expression of 1α-OHase enzymatic activity among noncancerous (PZHPV-7) and cancer cells (PC-3, DU145, LNCaP), which appears to correlate with 1α-OHase m-RNA synthesis and its promoter activities. Since it is well-established that EGF regulates the proliferation of prostate cells via autocrine and paracrine loops and 1α,25(OH) 2D inhibites prostate cell proliferation, we investigated if EGF also regulated 1α-OHase expression in prostate cells. We found that EGF upregulated 1α-OHase promoter activity and enzyme activity in PZ-HPV-7 and that 1α,25(OH) 2D 3 inhibited EGF-dependent up-regulation of 1α-OHase enzymatic activity. Moreover, the EGF-stimulated promoter activity was inhibited 70% by the MAPKK inhibitor, PD98059, suggesting that the MAPK pathway may be one pathway involved in the regulation of prostatic 1α-OHase by EGF to increase1α,25(OH) 2D synthesis as a feedback regulator of cell growth. Because EGF has no effect on 1α-OHase promoter activity in LNCaP cells, we propose that the ability of EGF to stimulate 1α,25(OH) 2D synthesis may be abolished or diminished in cancer cells.

Regulation of 1,25-dihydroxyvitamin d synthesis by intracellular vitamin d binding protein-1.

Control of 125-dihydroxyvitamin D (1,25-(OH)2D) synthesis is believed to be primarily at the level of expression of the vitamin D-1-hydroxylase (CYP1alpha; CYP1alpha) gene. Once transcribed, generation of product, as catalyzed by 1-hydroxylase, depends upon the availability of various co-factors, molecular oxygen, electrons as well as substrate to the enzyme. Here we provide evidence that the quantity of product 1,25-(OH)2D generated also relies on the presence and level of expression of the intracellular vitamin D binding protein-1 (IDBP-1) and its capacity to promote 24-hydroxylase (CYP24) gene expression. Stable transfection of the IDBP-1 cDNA increased 1,25-(OH)2D synthesis up to 700% (p < 0.001) in cells devoid of 24-hydroxylating potential but only 70% (p = 0.018) in cells in which the CYP24 gene is expressed. IDBP-1-mediated increase in 1,25-(OH)2D production was independent of any change in CYP1alpha expression but highly dependent on the ability of exogenously-added or endogenously-synthesized 1,25-(OH)2D to stimulate CYP24 gene expression. These data suggest that IDBP-1 is capable of controlling 1,25-(OH)2D production by modulating the delivery of 1) substrate 25-OHD to in the mitochondrial CYP1alpha gene product and 2) CYP1alpha product 1,25-(OH)2D to the vitamin D receptor for upregulation of expression of the catabolic CYP24 gene.

25-Hydroxyvitamin D-1α-hydroxylase activity is diminished in human prostate cancer cells and is enhanced by gene transfer

The hormone 1α,25-dihydroxyvitamin D (1α,25(OH) 2D) inhibits growth and induces differentiation of prostate cells. The enzyme responsible for 1α,25(OH) 2D synthesis, 25-hydroxyvitamin D (25(OH)D)–1α-hydroxylase (1α-OHase), has been demonstrated in human prostate cells. We compared the levels of 1α-OHase activity in prostate cancer cell lines, LNCaP, DU145 and PC-3 and in primary cultures of normal, cancerous and benign prostatic hyperplasia (BPH) prostate cells. We observed a marked decrease in 1α-OHase activity in prostate cancer cells, including an undetectable level of activity in LNCaP cells. Transient or stable transfection of 1α-OHase cDNA into LNCaP cells increased 1α-OHase activity from undetectable to 4.95 pmole/ mg±0.69 pmole/mg and 5.8 pmole/ mg±0.7 pmole/mg protein per hour, respectively. In response to 25(OH)D, the prohormone of 1α,25(OH) 2D, the transfected LNCaP cells showed a significant inhibition of 3 H -thymidine incorporation (37%±6% and 56%±4% at 10 −8 M for transiently and stably transfected cells, respectively). These findings support an important autocrine role for 1α,25(OH) 2D in the prostate and suggest that the re-introduction of the 1α-OHase gene to prostate cancer cells, in conjunction with the systemic administration of 25(OH)D, constitutes an endocrine form of gene therapy that may be less toxic than the systemic administration of 1α,25(OH) 2D.

(-)-Ledol from Calophyllum teysmanii: Structure and Stereochemistry

The bark extracts of Calophyllum teysmannii furnished (-)-ledol (1a) and its structure and stereochemistry were established by 2D NMR and synthesis from (+)-aromadendrene. Inconsistencies of previously reported data on the stereochemistry of (-)-ledol are discussed and corrected.

Preeclampsia is associated with low circulating levels of insulin-like growth factor I and 1,25-dihydroxyvitamin D in maternal and umbilical cord compartments.

Insulin-like growth factor I (IGF-I) stimulates renal and placental 1,25-dihydroxyvitamin D [1,25-(OH)2D] and is considered an important regulator of fetal growth. As 1,25-(OH)2D and birth weight are low in preeclampsia, this study was undertaken to determine whether circulating levels of IGF-I were associated with serum 1,25-(OH)2D concentrations in preeclamptic (PE group) and normotensive (NT group) pregnancies. Maternal and umbilical cord serum levels of IGF-I and 1,25-(OH)2D were significantly (P < 0.01) lower in the PE group than in the NT group. The concentrations of these two hormones correlated significantly in the umbilical cord (P < 0.05) and in the maternal (P < 0.001) compartments of the PE and NT groups, respectively. The amount of IGFBP-3 was 64% lower whereas that of IGFBP-1 was 2.9-fold higher in umbilical cord serum of the PE group compared with the NT group. In addition, maternal and umbilical cord serum IGF-I correlated significantly (P < 0.05) with weight and length at birth only in the PE group. In conclusion, the results of this study indicate that circulating IGF-I and 1,25-(OH)2D levels in both maternal and umbilical cord compartments are low in preeclampsia. Furthermore, this study suggests a differential regulatory effect of IGF-I on 1,25-(OH)2D synthesis and fetal growth depending on the presence or absence of preeclampsia.

Novel mutations in the 1alpha-hydroxylase (P450c1) gene in three families with pseudovitamin D-deficiency rickets resulting in loss of functional enzyme activity in blood-derived macrophages.

Pseudovitamin D-defiency rickets (PDDR) is an autosomal recessive disorder characterized by hypocalcemia, rickets (which are resistant to treatment with vitamin D), and low or undetectable serum levels of 1,25-dihydroxyvitamin D (1,25(OH)2D). The symptoms are corrected with 1,25(OH)2D treatment, and the disease is now believed to result from a defect in the cytochrome P450 component (P450c1; CYP27B1) of the renal 25-hydroxyvitamin D-1alpha-hydroxylase (1-OHase). We have studied genomic DNA from three families with PDDR and have identified the same homozygous mutation in the P450c1 gene in two of the index cases, causing a frameshift in exon 8, resulting in a premature stop codon in the heme-binding domain. The two cases in the third kindred were compound heterozygotes with missense mutations in exons 6 and 9. We have also identified a C/T polymorphism in intron 6 of the P450c1 genomic DNA. Interferon gamma-inducible 1-OHase activity in blood-derived macrophages was shown by 1,25(OH)2D synthesis in all control cells tested (37-184 fmol/h/106 cells) and those from the PDDR family parents (34-116 fmol/h/106 cells) but was totally absent from the patients' cells, indicating a defect in their macrophage 1-OHase, similar to the presumed renal defect. The assumption of similarity between the renal and macrophage P450c1 was supported by our ability to clone a 514 bp sequence, including the heme-binding region of the macrophage P450c1 cDNA from controls, which was identical to that published for both the renal and keratinocyte P450c1 cDNAs.