bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transgene‐mediated hyper‐expression of IL‐5 inhibits autoimmune disease but increases the risk of B cell chronic lymphocytic leukemia in a model of murine lupus
Authors: Wen Xiangshu , Zhang Danqing , Kikuchi Yuji , Jiang Yi , Nakamura Kazuhiro , Xiu Yan , Tsurui Hiromichi , Takahashi Kazuko , Abe Masaaki , Ohtsuji Mareki , Nishimura Hiroyuki , Takatsu Kiyoshi , Shirai Toshikazu , Hirose Sachiko 
Published: August 2004

AbstractIL‐5 preferentially activates B1 cells to produce natural antibodies cross‐reactive to self antigens. To determine the role of IL‐5 in antibody‐mediated autoimmune disease, we generated systemic lupus erythematosus (SLE)‐prone (NZB×NZW)F1 mice congenic for IL‐5 transgene (TG‐F1). The transgene unexpectedly reduced the incidence of lupus nephritis. Anti‐DNA antibodies in sera and those produced by splenic B cells in vitro were markedly decreased in TG‐F1 mice, while total polyclonal Ig levels were comparable to those in IL‐5 transgene‐negative (NZB×NZW)F1 (non‐TG‐F1) littermates. Flow cytometry‐sorted splenic B1 cells showed a significant reduction of anti‐DNA antibody synthesis in response to IL‐5, while proliferative responses to IL‐5 did not significantly differ between TG‐F1 and non‐TG‐F1 mice. As TG‐F1 mice aged, frequencies of peripheral B1 cells progressively increased, and the mice frequently developed B cell chronic lymphocytic leukemia (B‐CLL). Our results suggest that dysregulated, continuous high expression of IL‐5 in SLE‐prone mice may directly or indirectly mediate a skewed signaling of proliferation/differentiation of self‐antigen‐activated B1 cells, leading to suppression of autoimmune disease, but instead to aberrant expansion of B1 cells, giving rise to B‐CLL. Thus, this model may provide a clue to the pathogenesis of both SLE and B‐CLL.
The acute effects of L‐theanine in comparison with alprazolam on anticipatory anxiety in humans
Authors: Lu Kristy , Gray Marcus A. , Oliver Chris , Liley David T. , Harrison Ben J. , Bartholomeusz Cali F. , Phan K. Luan , Nathan Pradeep J. 
Published: July 2004

AbstractL‐Theanine (δ‐glutamylethylamide) is one of the predominant amino acids ordinarily found in green tea, and historically has been used as a relaxing agent. The current study examined the acute effects of L‐theanine in comparison with a standard benzodiazepine anxiolytic, alprazolam and placebo on behavioural measures of anxiety in healthy human subjects using the model of anticipatory anxiety (AA). Sixteen healthy volunteers received alprazolam (1 mg), L‐theanine (200 mg) or placebo in a double‐blind placebo‐controlled repeated measures design. The acute effects of alprazolam and L‐theanine were assessed under a relaxed and experimentally induced anxiety condition. Subjective self‐reports of anxiety including BAI, VAMS, STAI state anxiety, were obtained during both task conditions at pre‐ and post‐drug administrations. The results showed some evidence for relaxing effects of L‐theanine during the baseline condition on the tranquil–troubled subscale of the VAMS. Alprazolam did not exert any anxiolytic effects in comparison with the placebo on any of the measures during the relaxed state. Neither L‐theanine nor alprazalam had any significant anxiolytic effects during the experimentally induced anxiety state. The findings suggest that while L‐theanine may have some relaxing effects under resting conditions, neither L‐theanine not alprazolam demonstrate any acute anxiolytic effects under conditions of increased anxiety in the AA model. Copyright © 2004 John Wiley & Sons, Ltd.
Evidence for synergistic modulation of early information processing by nicotinic and muscarinic receptors in humans
Authors: Erskine F. F. , Ellis J. R. , Ellis K. A. , Stuber E. , Hogan K. , Miller V. , Moore E. , Bartholomeusz C. , Harrison B. J. , Lee B. , Phan K. L. , Liley D. , Nathan P. J. 
Published: July 2004

AbstractImpairments in early information processing are a hallmark feature of diverse neuropsychiatric disorders including schizophrenia and Alzheimer's disease (AD). Several lines of evidence implicate a dysfunction of the cholinergic system in these disorders, particularly in AD where there is known degeneration in major cholinergic pathways. Inspection time (IT), a measure of early visual information processing speed, has been shown to be sensitive to cholinergic manipulation. The current study employed the IT task to (1) examine the independent roles of nicotinic and muscarinic receptors in modulating information processing and (2) investigate the interaction of nicotinic and muscarinic receptor systems in modulating information processing. Twelve healthy participants completed a randomized, double‐blind, placebo‐controlled study under four drug conditions; (1) placebo, (2) mecamylamine (15 mg; oral), (3) scopolamine (0.4 mg, s.c.), (4) mecamylamine (15 mg)+scopolamine (0.4 mg). IT measures were examined at baseline and 2.5 h post drug administration. Selective blockade of nicotinic receptors with mecamylamine did not significantly impair IT, whereas selective blockade of muscarinic receptors with scopolamine produced a significant but small impairment in IT. Combined blockade of both receptor types with scopolamine and mecamylamine produced a large impairment in IT performance. The results indicate that both nicotinic and muscarinic receptors are involved in modulating IT, and that the two systems may function synergistically to modulate early visual information processing. These findings suggest that functional abnormalities in both nicotinic and muscarinic systems may underlie deficits in early visual information processing seen in disorders such as Alzheimer's disease and schizophrenia. Copyright © 2004 John Wiley & Sons, Ltd.
Lubrication and wear properties of grafted polyelectrolytes, hyaluronan and hylan, measured in the surface forces apparatus
Authors: Benz Marcel , Chen Nianhuan , Israelachvili Jacob 
Published: August 2004

AbstractHyaluronan is believed to have an important function in the boundary biolubrication of articular cartilage. Using a Surface Forces Apparatus, we tested the tribological properties of surface bound, rather than “free” hyaluronan. The grafting process of the polyelectrolyte included either a biological route via an HA‐binding protein or a chemical reaction to covalently bind the polymer to a lipid bilayer coated surface. In another reaction, we constructed a surface with covalently grafted hylan (crosslinked hyaluronan). We studied the normal and shear forces between these surfaces. None of the systems demonstrated comparable lubrication to that found between cartilage surfaces except at very low loads. Both grafted hyaluronan and hylan generated coefficients of friction between 0.15 and 0.3. Thus, the polysaccharide, which is a constituent of the lamina splendens (outermost cartilage layer), is not expected to be the responsible molecule for the great lubricity of cartilage; however, it may contribute to the load bearing and wear protection of these surfaces. This was concluded from the results with hylan, where a thin gel layer was sufficient to shield the underlying surfaces from damage even at applied pressures of over 200 atmospheres during shear. Our study shows that a low coefficient of friction is not a requirement for, or necessarily a measure of, wear protection. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 71A: 6–15, 2004
Chondrogenic differentiation of murine embryonic stem cells: Effects of culture conditions and dexamethasone
Authors: Tanaka Hiroshi , Murphy Christopher L. , Murphy Chiho , Kimura Mitsuhiro , Kawai Shinya , Polak Julia M. 
Published: July 2004

AbstractPluripotent embryonic stem (ES) cells have the capability to differentiate to various cell types and may represent an alternative cell source for the treatment of cartilage defects. Here, we show that differentiation of ES cells toward the chondrogenic lineage can be enhanced by altering the culture conditions. Chondrogenesis was observed in intact embryoid body (EB) cultures, as detected by an increase in mRNA levels for aggrecan and Sox9 genes. Collagen IIB mRNA, the mature chondrocyte‐specific splice variant, was absent at day 5, but appeared at later time points. Dexamethasone treatment of alginate‐encapsulated EB cultures did not have a strong chondrogenic effect. Nor was chondrogenesis enhanced by alginate encapsulation compared to simple plating of EBs. However, disruption of day 5 EBs and culture as a micromass or pelleted mass, significantly enhanced the expression of the cartilage marker gene collagen type II and the transcription factor Sox9 compared to all other treatments. Histological and immunohistochemical analysis of pellet cultures revealed cartilage‐like tissue characterized by metachromatically stained extracellular matrix and type II collagen immunoreactivity, indicative of chondrogenesis. These findings have potentially important implications for cartilage tissue engineering, since they may enable the increase in differentiated cell numbers needed for the in vitro development of functional cartilaginous tissue suitable for implantation. © 2004 Wiley‐Liss, Inc.
Differential transcriptional effects of PTH and estrogen during anabolic bone formation
Authors: von Stechow D. , Zurakowski D. , Pettit A.R. , Müller R. , Gronowicz G. , Chorev M. , Otu H. , Libermann T. , Alexander Joseph M. 
Published: July 2004

AbstractThe aim of this study was to compare transcriptional regulation in vivo during anabolic bone formation induced by either estradiol (E2) treatment or intermittent parathyroid hormone[1‐34] (PTH) therapy. We utilized an ovariectomized (OVX) mouse model of osteoporosis and transcriptional profiling to identify genes upregulated by either high‐dose E2 or PTH. Five weeks post‐OVX, the mice were administered either E2 and/or PTH, or vehicle for 4 weeks. Femoral bones were analyzed by microCT and histomorphometry to confirm the anabolic effect of each treatment. OVX vehicle‐treated control mice lost metaphyseal trabecular bone, with significant decrease in trabecular number, thickness, and connectivity. Both E2 and PTH treatments increased trabecular and cortical bone indices above the level of the sham operated controls, fully restoring both bone volume and bone mineral density (BMD). Moreover, PTH/E2 combination treatment led to significantly greater increase in cancellous bone and BMD than would be expected from the additive effects of the separate treatments. To determine whether PTH and E2 treatments were stimulating similar bone anabolic mechanisms, or were activating distinct signaling pathways, we compared patterns of gene expression using transcriptional profiling after either E2 or PTH treatment. After 4, 11, and 24 days of treatment, total RNA was collected from both the distal femoral metaphysis and diaphysis. Transcriptional profiling was performed using Affymetrix GeneChip probe arrays, comprised of approximately 36,000 full‐length mouse genes and EST clusters from the UniGene database. Several markers of osteoblast activity, including c‐fos, RANKL, PHEX, and PTHR1, were consistently upregulated by PTH in both skeletal sites. PTH treatment also increased expression of Cathespin K, consistent with the predicted increase in osteoclast activity. E2 treatment upregulated a largely distinct set of genes, including TGFβ3, and BMP1, as well as several genes critical for cell cycle control, including Cyclin D1 and CDK inhibitor 1A. Overall, comparison of transcriptional profiles suggest that anabolic responses in bone to PTH and high‐dose E2 treatment after OVX‐induced osteoporosis involve largely distinct patterns of gene regulation, each resulting in restoration of bone mass. © 2004 Wiley‐Liss, Inc.
Autoinhibited proteins as promising drug targets
Authors: Peterson Jeffrey R. , Golemis Erica A. 
Published: July 2004

AbstractCurrent drug discovery efforts generally focus on a limited number of protein classes, typically including proteins with well‐defined catalytic active sites (e.g., kinases) or ligand binding sites (e.g., G protein‐coupled receptors). Nevertheless, many clinically important pathways are mediated by proteins with no such obvious targets for small molecule inhibitors. Allosteric inhibitors offer an alternative approach to inhibition of protein activities, particularly for proteins that undergo conformational changes as part of their activity cycle. Proteins regulated by autoinhibitory domains represent one broad class of proteins that meets this criterion. In this article, we discuss the potential of autoinhibited proteins as targets for allosteric inhibitors and describe two examples of small molecules that act by stabilizing native autoinhibited conformations of their targets. We propose that proteins regulated by autoinhibition may be generally amenable to allosteric inhibition by small molecules that stabilize the native, autoinhibited fold. © 2004 Wiley‐Liss, Inc.
Changes in adipocyte hormones leptin, resistin, and adiponectin in thyroid dysfunction
Authors: Yaturu Subhashini , Prado Susan , Grimes Sidney R. 
Published: July 2004

AbstractThyroid hormones as well as the recently discovered secretory products of adipose tissue adiponectin and resistin take part in energy metabolism. To study the changes in the adipocyte hormones with changes in the thyroid functional status, we measured adiponectin, resistin, and leptin in 69 subjects with Graves' disease before and 32 patients at follow up after treatment for hyperthyroidism at hypothyroid state. Concentrations of serum adiponectin and resistin were higher in hyperthyroid state than in hypothyroid state (adiponectin: 5.73 ± 1.1 vs. 3.0 ± 0.5 ng/ml, P = 0.03) (resistin: 6.378 ± 0.6 vs. 5.81 ± 0.57 ng/ml, P < 0.0001). Resistin levels correlate positively with free t4(r = 0.37, P < 0.01), free t3 levels(r = 0.33, P < 0.01) and negatively with TSH(r = −0.22, P < 0.05). Adiponectin levels correlate with free t4(r = 0.33, P < 0.01) and free t3 (r = 0.44, P < 0.01). Though the adiponectin levels did not correlate with leptin or resistin levels, strong positive correlation of both resistin and adiponectin with thyroid hormones is noted. Serum levels of leptin did not change with change in the thyroid functional status (leptin: 53.38 ± 2.47 vs. 55.10 ± 2.58 NS). Leptin levels did not correlate with resistin and adiponectin. We conclude that thyroid function has effect on adipocyte hormones adiponectin and resistin but not leptin. © 2004 Wiley‐Liss, Inc.
Transforming growth factor beta stimulation of biglycan gene expression is potentially mediated by sp1 binding factors
Authors: Heegaard Anne‐Marie , Xie Zhongjian , Young Marian Frances , Nielsen Karina Lishmann 
Published: July 2004

AbstractBiglycan is a small leucine‐rich proteoglycan which is localized in the extracellular matrix of bone and other specialized connective tissues. Both biglycan mRNA and protein are up‐regulated by transforming growth factor‐β1 (TGF‐β1) and biglycan appears to influence TGF‐β1 activity. In this study, we have investigated the mechanism by which TGF‐β1, TGF‐β2 and TGF‐β3 stimulate biglycan mRNA expression in the osteoblastic cell line MG‐63. The cells were transfected with a series of deletional human biglycan promoter constructs and a region in the biglycan 5′ DNA was found to respond to TGF‐β1 with increased transcriptional activity in a dose‐dependent manner. Also TGF‐β2 and TGF‐β3, two structurally highly related TGF‐β isoforms stimulated biglycan transcription. A TGF‐β responsive region was identified within the first 218 bp of the human biglycan promoter upstream from the transcriptional start site, which contained several binding sites for the transcription factor Sp1. Electrophoretic mobility shift assays with nuclear extracts from MG‐63 cells showed binding of both Sp1 and Sp3 to a site at −216 to −208. When the biglycan promoter construct was co‐transfected with Sp1 and Sp3 expression vectors in Sp1‐deficient Drosophila Schneider‐2 cells, Sp1 induced the transcriptional activity of biglycan. Addition of Sp3 augmented the effect of Sp1 on biglycan gene expression. Induction of biglycan mRNA expression in response to TGF‐β in MG‐63 cells was abrogated by mithramycin, an inhibitor of Sp1 binding to GC‐rich DNA sequences. A mutation in the Sp1 site at −216 to −208 within the −218 biglycan promoter construct substantially diminished the transcriptional up‐regulation by TGF‐β1. Taken together this data shows for the first time that TGF‐β1 stimulation of human biglycan mRNA expression relies on increased transcription of the biglycan gene, and is mediated by members of the Sp1 family of transcription factors. © 2004 Wiley‐Liss, Inc.
Long‐term in vitro analysis of limb cartilage development: Involvement of Wnt signaling
Authors: Daumer Kathleen M. , Tufan A. Cevik , Tuan Rocky S. 
Published: July 2004

AbstractEndochondral skeletal development involves the condensation of mesenchymal cells, their differentiation into chondrocytes, followed by chondrocyte maturation, hypertrophy, and matrix mineralization, and replacement by osteoblasts. The Wnt family of secreted proteins have been shown to play important roles in vertebrate limb formation. To examine the role(s) of Wnt members and their transmembrane‐spanning receptor(s), Frizzled (fz), we retrovirally misexpressed Wnt‐5a, Wnt‐7a, chicken frizzled‐1 (Chfz‐1), and frizzled‐7 (Chfz‐7) in long‐term (21 day) high density, micromass cultures of stage 23/24 chick embryonic limb mesenchyme. This culture system recapitulates in vitro the entire differentiation (days 1–10), growth (days 5–12), and maturation and hypertrophy (from day 12 on) program of cartilage development. Wnt‐7a misexpression severely inhibited chondrogenesis from day 7 onward. Wnt‐5a misexpression resulted in a poor hypertrophic phenotype by day 14. Chfz‐7 misexpression caused a slight delay of chondrocyte maturation based on histology, whereas Chfz‐1 misexpression did not affect the chondrogenic phenotype. Misexpression of all Wnt members decreased collagen type X expression and alkaline phosphatase activity at day 21. Our findings implicate functional role(s) for Wnt signaling throughout embryonic cartilage development, and show the utility of the long‐term in vitro limb mesenchyme culture system for such studies. © 2004 Wiley‐Liss, Inc.
Myocardin/MKL family of SRF coactivators: Key regulators of immediate early and muscle specific gene expression
Authors: Cen Bo , Selvaraj Ahalya , Prywes Ron 
Published: July 2004

AbstractMyocardin, megakaryoblastic leukemia‐1 (MKL1), and MKL2 belong to a newly defined family of transcriptional coactivators. All three family members bind to serum response factor (SRF) and strongly activate transcription from promoters with SRF binding sites. SRF is required for the serum induction of immediate early genes such as c‐fos and for the expression of many muscle specific genes. Consistent with a role in muscle specific gene expression, myocardin is specifically expressed in cardiac and smooth muscle cells while MKL1 and 2 are broadly expressed. Myocardin has particularly been shown to be required for smooth muscle development while MKL1/2 are required for the RhoA signaling pathway for induction of immediate early genes. SRF can be activated by at least two families of coactivators, p62TCF and myocardin/MKL. These factors bind to the same region of SRF such that their binding is mutually exclusive. This provides one mechanism of regulation of SRF target genes by pathways that differentially activate the coactivators. The RhoA pathway appears to activate MKL1 by altering MKL1's binding to actin and causing MKL1's translocation from the cytoplasm to the nucleus. However, this mechanism of activation of the myocardin/MKL family has not been observed in all cell types such that other regulatory mechanism(s) likely exist. In particular, rapid serum inducible phosphorylation of MKL1 was observed. The regulation of this coactivator family is key to understanding how SRF target genes are activated during muscle cell differentiation or growth factor induced cell proliferation. © 2004 Wiley‐Liss, Inc.
Effect of overexpression and nuclear translocation of constitutively active PKB‐α on cellular survival and proliferation in HepG2 cells
Authors: Gupta Dhananjay , Syed Noor A. , Roesler William J. , Khandelwal Ramji L. 
Published: July 2004

AbstractProtein kinase B (Akt/PKB) is a key component in the PI 3‐kinase mediated cell survival pathway and has oncogenic transformation potential. Although the over‐expression of PKB‐α can prevent cell death following growth factor withdrawal, the long‐term effects of stable over‐expression of PKB‐α on cell survival in the absence of growth factors remain to be resolved. In the present study, we generated HepG2 cells with stable expression of active PKB‐α and compared its characteristics with HepG2 cells. Basal as well as insulin‐stimulated levels of Ser473 and Thr308 phosphorylation in PKB‐α transfected HepG2 cells were much higher than HepG2 cells. Constitutive expression of active PKB‐α enabled HepG2 cells to survive up to 96 h without serum in growth media while HepG2 cells fail to survive after 48 h of serum withdrawal. A strong positive correlation (R2 = 0.71) between cell proliferation and phosphorylated form of PKB‐α at Thr308 was observed along with higher levels of phosphorylated 3′‐phosphoinositide‐dependent kinase‐1 (PDK‐1). HepG2 cells with constitutive expression of active PKB‐α also showed higher levels of phosphorylated p65 subunit of nuclear factor‐κB (NFκB) in comparison with HepG2 cells. Predominant nuclear localization of phosphorylated PKB‐α was observed in stably transfected HepG2 cells. These results indicate that constitutive expression of active PKB‐α renders HepG2 cells independent of serum based growth factors for survival and proliferation. © 2004 Wiley‐Liss, Inc.
Changes in receptor activator of nuclear factor‐kappaB, and its ligand, osteoprotegerin, bone‐type alkaline phosphatase, and tartrate‐resistant acid phosphatase in ovariectomized rats
Authors: Miyazaki Takashi , Matsunaga Toshiyuki , Miyazaki Shuichi , Hokari Shigeru , Komoda Tsugikazu 
Published: July 2004

AbstractWe investigated time‐course changes in the expression of receptor activator of nuclear factor‐kappaB (RANK), its ligand (RANKL), osteoprotegerin (OPG), bone‐type alkaline phosphatase (BAP), and tartrate‐resistant acid phosphatase (TRAP) in ovariectomized (OVX) rats. Samples of sera and coccyges were used for analysis of the enzyme activities and expression levels of proteins and mRNAs, and an immunohistochemical analysis was also performed. Serum BAP activity increased to 158.6% of the pre‐operation value at 1 week after OVX, and then decreased to 38.7% at 8 weeks after OVX. On the other hand, the serum TRAP activity increased to 130.9% of the pre‐operation level at 1 week after OVX, and was maintained at a high level, compared with the pre‐operation level. The patterns of BAP and TRAP activity in the coccyges specimens were similar to those seen in the sera. The expression profiles of TRAP, RANK, and RANKL proteins in the coccyx specimens were similar to the pattern of serum TRAP activity, while the profiles of the BAP and OPG proteins were similar to the pattern of serum BAP activity in OVX rats. The changes in the mRNA expression levels of the osteogenic proteins were similar to those for protein expression. These biochemical changes in OVX rats were confirmed by immunohistochemical studies. Our results suggest that not only osteoclastogenesis accelerated but also osteoblastogenesis transiently increased during the early phase of osteoporosis. © 2004 Wiley‐Liss, Inc.