701
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Park H, Park CB, Tzoganakis C, Chen P. Effect of Molecular Weight on the Surface Tension of Polystyrene Melt in Supercritical Nitrogen. Ind Eng Chem Res 2007. [DOI: 10.1021/ie070311j] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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702
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Ramírez J, Mirkov S, Zhang W, Chen P, Das S, Liu W, Ratain MJ, Innocenti F. Hepatocyte nuclear factor-1 alpha is associated with UGT1A1, UGT1A9 and UGT2B7 mRNA expression in human liver. THE PHARMACOGENOMICS JOURNAL 2007; 8:152-61. [PMID: 17440429 DOI: 10.1038/sj.tpj.6500454] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Experimental evidence suggests HNF1alpha regulates UGT expression. This study investigates (1) whether the variability in HNF1alpha expression is associated with the variability in UGT1A1, UGT1A9 and UGT2B7 expression in human livers and (2) the functionality of 12 HNF1alpha variants using mRNA expression as phenotype. Controlling for known UGT variation in cis-acting elements known to affect UGT expression, we demonstrate that a combination of HNF1alpha mRNA levels and UGT genotype predicts variance in UGT expression to a higher extent than UGT genotype alone. None of the HNF1alpha polymorphisms studied, however, seem to have an effect on HNF1alpha, UGT1A1, UGT1A9 and UGT2B7 expression, ruling out their functional role. Our data provide evidence for HNF1alpha being a determinant of UGT1A1, UGT1A9 and UGT2B7 mRNA expression. However, the amount of UGT intergenotype variability explained by HNF1alpha expression appears to be modest, and further studies should investigate the role of multiple transcription factors.
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703
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Gueven N, Chen P, Nakamura J, Becherel OJ, Kijas AW, Grattan-Smith P, Lavin MF. A subgroup of spinocerebellar ataxias defective in DNA damage responses. Neuroscience 2007; 145:1418-25. [PMID: 17224243 DOI: 10.1016/j.neuroscience.2006.12.010] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2006] [Revised: 12/06/2006] [Accepted: 12/07/2006] [Indexed: 01/16/2023]
Abstract
A subgroup of human autosomal recessive ataxias is also characterized by disturbances of eye movement or oculomotor apraxia. These include ataxia telangiectasia (A-T); ataxia telangiectasia like disorder (ATLD); ataxia oculomotor apraxia type 1 (AOA1) and ataxia oculomotor apraxia type 2 (AOA2). What appears to be emerging is that all of these have in common some form of defect in DNA damage response which could account for the neurodegenerative changes seen in these disorders. We describe here sensitivity to DNA damaging agents in AOA1 and evidence that these cells have a defect in single strand break repair. Comparison is made with what appears to be a novel form of AOA (AOA3) which also shows sensitivity to agents that lead to single strand breaks in DNA as well as a reduced capacity to repair these breaks. AOA3 cells are defective in the DNA damage-induced p53 response. This defect can be overcome by incubation with the mdm2 antagonists, nutlins, but combined treatment with nutlins and DNA damage does not enhance the response. We also show that AOA3 cells are deficient in p73 activation after DNA damage. These data provide further evidence that different forms of AOA have in common a reduced capacity to cope with damage to DNA, which may account for the neurodegeneration observed in these syndromes.
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704
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Park H, Thompson RB, Lanson N, Tzoganakis C, Park CB, Chen P. Effect of Temperature and Pressure on Surface Tension of Polystyrene in Supercritical Carbon Dioxide. J Phys Chem B 2007; 111:3859-68. [PMID: 17388548 DOI: 10.1021/jp065851t] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The surface tension of polymers in a supercritical fluid is one of the most important physicochemical parameters in many engineering processes, such as microcellular foaming where the surface tension between a polymer melt and a fluid is a principal factor in determining cell nucleation and growth. This paper presents experimental results of the surface tension of polystyrene in supercritical carbon dioxide, together with theoretical calculations for a corresponding system. The surface tension is determined by Axisymmetric Drop Shape Analysis-Profile (ADSA-P), where a high pressure and temperature cell is designed and constructed to facilitate the formation of a pendent drop of polystyrene melt. Self-consistent field theory (SCFT) calculations are applied to simulate the surface tension of a corresponding system, and good qualitative agreement with experiment is obtained. The physical mechanisms for three main experimental trends are explained by using SCFT, and none of the explanations quantitatively depend on the configurational entropy of the polymer constituents. These calculations therefore rationalize the use of simple liquid models for the quantitative prediction of surface tensions of polymers. As pressure and temperature increase, the surface tension of polystyrene decreases. A linear relationship is found between surface tension and temperature, and between surface tension and pressure; the slope of surface tension change with temperature is dependent on pressure.
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705
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Gueven N, Becherel OJ, Howe O, Chen P, Haince JF, Ouellet ME, Poirier GG, Waterhouse N, Fusser M, Epe B, de Murcia JM, de Murcia G, McGowan CH, Parton R, Mothersill C, Grattan-Smith P, Lavin MF. A novel form of ataxia oculomotor apraxia characterized by oxidative stress and apoptosis resistance. Cell Death Differ 2007; 14:1149-61. [PMID: 17347666 DOI: 10.1038/sj.cdd.4402116] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Several different autosomal recessive genetic disorders characterized by ataxia with oculomotor apraxia (AOA) have been identified with the unifying feature of defective DNA damage recognition and/or repair. We describe here the characterization of a novel form of AOA showing increased sensitivity to agents that cause single-strand breaks (SSBs) in DNA but having no gross defect in the repair of these breaks. Evidence for the presence of residual SSBs in DNA was provided by dramatically increased levels of poly (ADP-ribose)polymerase (PARP-1) auto-poly (ADP-ribosyl)ation, the detection of increased levels of reactive oxygen/nitrogen species (ROS/RNS) and oxidative damage to DNA in the patient cells. There was also evidence for oxidative damage to proteins and lipids. Although these cells were hypersensitive to DNA damaging agents, the mode of death was not by apoptosis. These cells were also resistant to TRAIL-induced death. Consistent with these observations, failure to observe a decrease in mitochondrial membrane potential, reduced cytochrome c release and defective apoptosis-inducing factor translocation to the nucleus was observed. Apoptosis resistance and PARP-1 hyperactivation were overcome by incubating the patient's cells with antioxidants. These results provide evidence for a novel form of AOA characterized by sensitivity to DNA damaging agents, oxidative stress, PARP-1 hyperactivation but resistance to apoptosis.
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706
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Ramakrishnan S, Strader AD, Wimpee B, Chen P, Smith MS, Buntin JD. Evidence for increased neuropeptide Y synthesis in mediobasal hypothalamus in relation to parental hyperphagia and gonadal activation in breeding ring doves. J Neuroendocrinol 2007; 19:163-71. [PMID: 17280589 DOI: 10.1111/j.1365-2826.2006.01520.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Like lactating mammals, male and female ring dove parents increase their food consumption to meet the energetic challenges of provisioning their young. To clarify the neurochemical mechanisms involved, the present study investigated the relationship between parental hyperphagia and changes in activity of the potent orexigen neuropeptide Y (NPY) in the hypothalamus of breeding doves. Changes in NPY-immunoreactive (NPY-ir) cell numbers in the tuberal hypothalamus of male and female doves were examined by immunocytochemistry at six stages of the breeding cycle. Parallel NPY mRNA measurements were recorded in mediobasal hypothalamus (which includes the tuberal hypothalamus) by semiquantitative reverse transcription-polymerase chain reaction using 18S rRNA as the internal standard. NPY mRNA changes were also measured in the mediobasal hypothalamus of nonbreeding doves following intracranial administration of prolactin, an orexigenic hormone that is elevated in the plasma of parent doves, and in response to food deprivation, which mimics the negative energy state that develops in parents as they provision their growing young. NPY-ir cell numbers in the tuberal hypothalamus and NPY mRNA levels in the mediobasal hypothalamus were significantly higher in breeding males and females during the period of parental hyperphagia after hatching than during the late incubation period when food intake remains unchanged. In nonbreeding doves, food deprivation and prolactin treatment increased NPY mRNA in this region by two- to three-fold, which suggests that NPY expression is sensitive to hormonal and metabolic signals associated with parenting. We conclude that NPY synthesis is increased in the mediobasal hypothalamus during the posthatching period, which presumably supports increased NPY release and resulting parental hyperphagia. NPY-ir and mRNA were also high in the mediobasal hypothalamus prior to egg laying when food intake remained unchanged. Several lines of evidence suggest that this elevation in NPY supports the increased gonadal activity that accompanies intense courtship and nest building interactions in breeding doves.
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707
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Xiong Z, Hu J, Wu G, Liu Y, Chen P. Large amount of hydrogen desorption and stepwise phase transition in the chemical reaction of NaNH2 and LiAlH4. Catal Today 2007. [DOI: 10.1016/j.cattod.2006.09.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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708
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Brant-Zawadzki G, Mathews MSG, Duma CM, Kim B, Chen P, Heinemann S, Brant-Zawadzki M. Central neurocytoma: case report of an 81-year-old and histopathologic findings. Neuroradiol J 2007; 20:61-6. [PMID: 24299591 DOI: 10.1177/197140090702000110] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2007] [Accepted: 01/29/2007] [Indexed: 11/15/2022] Open
Abstract
Central Neurocytomas are rare and usually benign tumors found primarily in the lateral ventricles of the brain. Central Neurocytomas are composed of uniform round cells exhibiting neuronal differentiation and are found almost exclusively in young adults between 15 and 60 years of age. The authors report the case of an 81-year-old man with a history of severe psychosis and depression, who presented with progressive confusion and ataxia likely unrelated to a central neurocytoma of his right lateral ventricle. The patient underwent a stereotactic biopsy of the lesion, followed by Gamma Knife radiosurgery. Histopathology showed immunohistological staining for synaptophysin, neuron specific enolase (NSE) and neuronal nuclear antigen (NeuN). A review of published literature on central neurocytomas revealed that this tumor occurs most frequently in young adults with a median age between 25 and 30 years. This pathology has never been reported in patients over the age of 80. Gamma Knife radiosurgery was successful in decreasing the tumor volume by 20% at the four month follow-up, but the fact that the patient died of unrelated occurrences in the elderly cannot be ruled out. Patients with central neurocytomas commonly present with obstructive hydrocephalus and immediate treatment may be necessary to tide over urgent situations.
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709
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Gugino BK, Carroll JE, Widmer TL, Chen P, Abawi GS. An IPM Program for Managing Fungal Leaf Blight Diseases of Carrot in New York. PLANT DISEASE 2007; 91:59-65. [PMID: 30781067 DOI: 10.1094/pd-91-0059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Fungal leaf blight diseases caused by Cercospora carotae and Alternaria dauci occur annually on processing carrot in New York, with growers applying up to eight fungicide sprays to manage these diseases. An integrated pest management (IPM) program involving the use of a 25% disease incidence threshold to prompt the first fungicide application and timing subsequent sprays by monitoring for increases in disease severity and weather forecasts in conjunction with a 10- to 14-day spray interval was evaluated in grower fields in 1997 and 1998. The IPM plots, compared with the grower plots, required two to six fewer fungicide applications but showed no yield reduction. From 1999 to 2004, the IPM program was validated and the effect of crop rotation and carrot cultivar susceptibility also were assessed. Carrot plants growing in fields with 2-year or longer crop rotation intervals reached the 25% disease incidence threshold later in the season and required fewer fungicide applications. The less-susceptible carrot cultivars also reached the 25% disease incidence threshold later, required fewer fungicide applications, and were less severely diseased than more susceptible cultivars. Validation of the IPM program in New York showed that both fungal leaf blights can be managed effectively using a 25% incidence threshold to prompt the first fungicide spray and making the subsequent fungicide applications based on increases in disease severity, weather forecasts, and a 10- to 14-day spray interval.
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710
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Sigmund E, Cho H, Chen P, Byrnes S, Song YQ, Guo X, Brown TR. Diffusion-based MR methods for bone structure and evolution. Magn Reson Med 2007; 59:28-39. [DOI: 10.1002/mrm.21281] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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711
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Miller PD, Schwartz EN, Chen P, Misurski DA, Krege JH. Teriparatide in postmenopausal women with osteoporosis and mild or moderate renal impairment. Osteoporos Int 2007; 18:59-68. [PMID: 17013567 DOI: 10.1007/s00198-006-0189-8] [Citation(s) in RCA: 147] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2005] [Accepted: 06/15/2006] [Indexed: 10/24/2022]
Abstract
INTRODUCTION The prevalence of both osteoporosis and renal impairment increases with age. METHODS Using data from the Fracture Prevention Trial, the safety and efficacy of teriparatide [rhPTH(1-34)] in postmenopausal women with osteoporosis and renal impairment were explored. Patients were required to have serum creatinine concentrations < or =2.0 mg/dl and normal serum parathyroid hormone (PTH) concentrations and were randomized to receive daily subcutaneous injections of placebo or teriparatide 20 or 40 mcg/day. Glomerular filtration rate (GFR) was estimated using the Cockcroft-Gault equation. Patients were defined from baseline assessments to have normal (GFR > or =80 ml/min), mildly impaired (GFR 50-79 ml/min), or moderately impaired (GFR 30-49 ml/min) renal function for bone mineral density (BMD) and amino-terminal extension peptide of procollagen type 1 (PINP) analyses, and normal (GFR > or =80 ml/min) or impaired (GFR <80 ml/min) renal function for fracture analyses. RESULTS AND CONCLUSIONS Compared with patients with normal renal function, patients with renal impairment were older, shorter, weighed less, had been postmenopausal longer, and had lower baseline lumbar spine and femoral neck BMD. Compared with placebo, teriparatide significantly increased PINP and lumbar spine and femoral neck BMD within each renal function subgroup, and there was no evidence that these increases were altered by renal insufficiency (each treatment-by-subgroup interaction p>0.05). Similarly, teriparatide-mediated vertebral and nonvertebral fracture risk reductions were similar and did not differ significantly between patients with normal or impaired renal function (treatment-by-subgroup interactions p>0.05). The incidences of treatment-emergent and renal-related adverse events were consistent across treatment assignment in the normal, mildly impaired, and moderately impaired renal function subgroups. Teriparatide induced changes in mean GFR were unaffected by baseline renal function (treatment-by-renal function interaction p>0.05 for normal, mildly impaired, or moderately impaired subgroups). Patients in all renal function categories treated with teriparatide 20 or 40 mcg had an increased incidence of 4-6-h postdose serum calcium >10.6 mg/dl (the upper limit of normal) versus placebo; however, teriparatide 20 mcg/day was not associated with significantly increased incidence of 4-6-h postdose serum calcium >11 mg/dl in any renal function category. Teriparatide therapy was associated with increased incidence of elevated uric acid, with the incidences being highest in patients with moderately impaired renal function and in those receiving teriparatide 40 mcg/day. Even so, adverse event data did not suggest an increased incidence of gout or arthralgia or of nephrolithiasis events in teriparatide-treated patients with normal, mild, or moderate renal impairment.
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712
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Genant HK, Delmas PD, Chen P, Jiang Y, Eriksen EF, Dalsky GP, Marcus R, San Martin J. Severity of vertebral fracture reflects deterioration of bone microarchitecture. Osteoporos Int 2007; 18:69-76. [PMID: 17028792 DOI: 10.1007/s00198-006-0199-6] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2006] [Accepted: 07/03/2006] [Indexed: 01/08/2023]
Abstract
INTRODUCTION Bone microarchitecture, a component of bone strength, is generally measured on transiliac bone biopsy samples. The objective of this study was to determine whether assessment of four grades of vertebral fracture severity could serve as a noninvasive surrogate marker for trabecular bone volume and microarchitecture. METHODS Baseline vertebral fracture severity was determined by semiquantitative assessment of spine radiographs from 190 postmenopausal women with osteoporosis. Bone-structure indices were obtained by 2D histomorphometry and 3D microcomputed tomography (CT) analyses. Significance of differences was determined after adjusting for age, height, and lumbar spine bone mineral density. RESULTS There were significant (P < 0.05) trends in decreasing bone volume, trabecular number, and connectivity, and increasing trabecular separation with greater vertebral fracture severity. Histomorphometric bone volume was 25 and 36% lower (P < 0.05) in women with moderate and severe fractures than in women with no fractures, respectively. Compared with women without fractures, women with mild, moderate, and severe fractures had lower (P < 0.05) microCT bone volume (23, 30, and 51%, respectively). CONCLUSIONS Microarchitectural deterioration was progressively worse in women with increasing severity of vertebral fractures. We conclude that assessment of vertebral fracture severity is an important clinical tool to evaluate the severity of postmenopausal osteoporosis.
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713
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Fung SY, Yang H, Chen P. Formation of colloidal suspension of hydrophobic compounds with an amphiphilic self-assembling peptide. Colloids Surf B Biointerfaces 2006; 55:200-11. [PMID: 17234393 DOI: 10.1016/j.colsurfb.2006.12.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2006] [Revised: 11/29/2006] [Accepted: 12/01/2006] [Indexed: 11/23/2022]
Abstract
The amphiphilic self-assembling peptide EAK16-II was found to be able to stabilize hydrophobic compounds in aqueous solution. Micro/nanocrystals of a hydrophobic compound, pyrene, and a hydrophobic anticancer agent, ellipticine, were stabilized by EAK16-II to form colloidal suspensions in water. Initial evidence of the association between EAK16-II and hydrophobic compounds was the observation of a clouding phenomenon and a difference in fluorescence spectra of the solution. A further investigation on the interaction between EAK16-II and pyrene was carried out using fluorescence spectroscopy and scanning electron microscopy (SEM). It was found that the pyrene-peptide complex formation required mechanical stirring, and the freshly prepared peptide solution (containing peptide monomers and/or peptide protofibrils) was more effective at stabilizing pyrene than the mature fibrils in aged peptide solutions. The time duration over which the complex formed was about 22 h. The data on the complexation of pyrene and EAK16-II at various concentrations suggested that the maximum amount of stabilized pyrene was concentration dependent. SEM images showed that peptide concentration did not significantly affect the size of the complexes/suspensions but altered the structures of the peptide coating on the surface of the complex. Atomic force microscopy (AFM) was conducted to study the interaction of EAK16-II with a model hydrophobic surface, which provided some detailed information of how peptide adsorbed onto the hydrophobic compounds and stabilize them. This study shows the potential of self-assembling peptides for encapsulation of hydrophobic compounds.
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714
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Gallagher JC, Rosen CJ, Chen P, Misurski DA, Marcus R. Response rate of bone mineral density to teriparatide in postmenopausal women with osteoporosis. Bone 2006; 39:1268-75. [PMID: 16884968 DOI: 10.1016/j.bone.2006.06.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2006] [Revised: 05/19/2006] [Accepted: 06/20/2006] [Indexed: 11/28/2022]
Abstract
PURPOSE It is desirable for clinicians to know what bone mineral density (BMD) response they can expect in women treated with osteoporosis therapies. The focus of this analysis was to determine what percentage of women attained a lumbar spine BMD response to teriparatide that equaled or exceeded the least significant change (LSC) value of 3%. METHODS Data from three clinical trials involving postmenopausal women with osteoporosis were examined. The Fracture Prevention Trial was a double-blinded, placebo-controlled clinical trial examining the safety and efficacy of teriparatide 20 and 40 microg/day. The other two trials were double-blinded, head-to-head comparisons of alendronate 10 mg/day and teriparatide 20 or 40 microg/day, respectively. Only treatment-compliant women who had lumbar spine BMD measurements at all specified time points in these trials were included. For reference, we also examined the percentage of women with lumbar spine BMD responses to alendronate. Hip BMD responses that equaled or exceeded 3% were also examined. RESULTS According to the LSC criteria, 91% of the teriparatide 20 microg/day group and 94% of the teriparatide 40 microg/day group were lumbar spine BMD responders at 18 months in the Fracture Prevention Trial. In the teriparatide 20 microg/alendronate head-to-head trial, 94% of women receiving teriparatide had a lumbar spine BMD response that equaled or exceeded the 3% criterion at 18 months compared to 75% of those receiving alendronate 10 mg/day (p < 0.01). In the teriparatide 40 microg/day group of the other head-to-head trial, 92% of women achieved the 3% criterion for the lumbar spine at 12 months compared to 69% of those receiving alendronate 10 mg/day (p < 0.01). The median 3-month change in amino-terminal extension peptide of procollagen type 1 [PINP] in women who had a lumbar spine BMD response to teriparatide at 18 months was larger than in women who did not have a lumbar spine BMD response. However, the median 3-month PINP change in lumbar spine BMD nonresponders still exceeded the LSC value of 10 microg/L. Although the percentage of teriparatide-treated women with a hip BMD response that met the 3% criterion was significantly greater than for placebo, there was no significant difference between the percentage of teriparatide 20 microg/day and alendronate 10 mg/day responders in the comparison trial. The baseline characteristics of teriparatide lumbar spine responders and nonresponders were similar. CONCLUSION This analysis demonstrates that the vast majority of treatment-compliant postmenopausal women with osteoporosis and minimal prior bisphosphonate exposure have a lumbar spine BMD response to teriparatide that meets or exceeds the LSC. The characteristics of teriparatide responders and nonresponders were not significantly different; thus, we were unable to discern any characteristics that could be used to identify potential nonresponders.
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715
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Long J, Chen P. On the role of energy barriers in determining contact angle hysteresis. Adv Colloid Interface Sci 2006; 127:55-66. [PMID: 17094933 DOI: 10.1016/j.cis.2006.09.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2006] [Revised: 09/15/2006] [Accepted: 09/20/2006] [Indexed: 10/23/2022]
Abstract
The thermodynamic model of contact angles on rough, heterogeneous surfaces developed by Long et al. [J. Long, M.N. Hyder, R.Y.M. Huang and P. Chen, Adv. Colloid Interface Sci. 118 (2005) 173] was employed to study the role of energy barriers in determining contact angle hysteresis. Major energy barriers corresponding to metastable states and minor energy barriers corresponding to secondary metastable states were defined. Distributions of major and/or minor energy barriers as a function of apparent contact angle for various surfaces were obtained. The reproducibility of contact angle measurement, the effect of vibrational energy on contact angle hysteresis and the "stick-slip" phenomenon were discussed. Quantitative relations between contact angles and vibrational energy were obtained. It was found that receding contact angles are normally poorly reproducible for hydrophilic surfaces, but for extremely hydrophobic surfaces, advancing contact angles may have a poor reproducibility. When the vibrational energy available to a system increases, the measured advancing contact angle will decrease while the receding angle will increase until both reach a common value: the system equilibrium angle. This finding not only agrees well with the experimental observations in system equilibrium contact angle measurements, but also lays a theoretical foundation for such measurements. A small vibrational energy may result in a "stick-slip" phenomenon.
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716
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Yi T, Wei YQ, Tian L, Zhao X, Li J, Deng HX, Wen YJ, Zou CH, Tan GH, Kan B, Su JM, Jiang Y, Mao YQ, Chen P, Wang YS. Humoral and cellular immunity induced by tumor cell vaccine based on the chicken xenogeneic homologous matrix metalloproteinase-2. Cancer Gene Ther 2006; 14:158-64. [PMID: 17124509 DOI: 10.1038/sj.cgt.7700994] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Matrix metalloproteinase-2 (MMP-2) has been used as a target for cancer immunotherapy. The activation of immunization by breaking immune tolerance to self-MMP-2 may be one of the promising approaches for the treatment of MMP-2-positive tumors. In this study, we constructed the xenogeneic tumor cell vaccine c-MMP-2 by transfecting CT26 and LLC cells with chicken MMP-2 cDNA constructs. MMP-2-specific autoantibodies in sera and tumor cells were found in mice immunized with c-MMP-2. Protection against tumor growth was evaluated in respect of the relative contributions of autoantibodies, CD4+, and CD8+ T cells. Treatment with this vaccine (c-MMP-2) also prolonged the survival time of mice bearing cancer. The specific cytotoxic T-cell responses suggested that the treatment increased CD8+ T-cell activity. The antitumor activity of c-MMP-2 was abrogated by in vivo depletion of CD4+ and CD8+ T-lymphocytes and improved by adoptive transfer of CD4+ and CD8+ T-lymphocytes from the mice treated with c-MMP-2. An alternative DNA vaccination strategy for cancer therapy was identified in this study by eliciting humoral and cellular immunoresponse with a crossreacting transfectant.
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717
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Kim YR, Chen P, Aziz MJ, Branton D, Vlassak JJ. Focused ion beam induced deflections of freestanding thin films. JOURNAL OF APPLIED PHYSICS 2006; 100:104322-104330. [PMID: 22485053 PMCID: PMC3319714 DOI: 10.1063/1.2363900] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Prominent deflections are shown to occur in freestanding silicon nitride thin membranes when exposed to a 50 keV gallium focused ion beam for ion doses between 10(14) and 10(17) ions/cm(2). Atomic force microscope topographs were used to quantify elevations on the irradiated side and corresponding depressions of comparable magnitude on the back side, thus indicating that what at first appeared to be protrusions are actually the result of membrane deflections. The shape in high-stress silicon nitride is remarkably flattopped and differs from that in low-stress silicon nitride. Ion beam induced biaxial compressive stress generation, which is a known deformation mechanism for other amorphous materials at higher ion energies, is hypothesized to be the origin of the deflection. A continuum mechanical model based on this assumption convincingly reproduces the profiles for both low-stress and high-stress membranes and provides a family of unusual shapes that can be created by deflection of freestanding thin films under beam irradiation.
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718
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Ghilezan M, Kestin L, Gustafson G, Brabbins D, Vicini F, Chen P, Yan D, Martinez A. 105. Int J Radiat Oncol Biol Phys 2006. [DOI: 10.1016/j.ijrobp.2006.07.135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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719
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Duan ZG, Yan XJ, He XZ, Zhou H, Chen P, Cao R, Xiong JX, Hu WJ, Wang XC, Liang SP. Extraction and protein component analysis of venom from the dissected venom glands of Latrodectus tredecimguttatus. Comp Biochem Physiol B Biochem Mol Biol 2006; 145:350-7. [PMID: 17029995 DOI: 10.1016/j.cbpb.2006.08.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2006] [Revised: 08/14/2006] [Accepted: 08/24/2006] [Indexed: 11/28/2022]
Abstract
Black widow spiders (genus Latrodectus) have attracted increasing attention due to frequently reported human injuries caused by them and the potential applications of biologically active components in their venoms. Although a number of studies have described the biological properties and structures of several venomous proteins such as latrotoxins, a comprehensive analysis of protein component of the venom from the spider is not available. We used combinative proteomic strategies to assess the protein components of the crude venom collected from Latrodectus tredecimguttatus by extracting the dissected venom glands. The experiments demonstrated that the crude venom of L. tredecimguttatus has a high abundance of acidic proteins with molecular masses greater than 15 kDa, and the content of proteins and peptides of below 15 kDa is low. 86 unique proteins were identified, part of which were contaminations of cellular components during the extraction, determined in comparison with venom obtained by electrostimulation. Except for members of latrotoxin family that were commonly considered as the primary toxic components of the venom, several other special enzymes and proteins were detected such as protease, phosphatase, lysozyme, inhibitory protein, and so on. These protein components, particularly the proteases, were speculated to play important roles in the action of L. tredecimguttatus venom.
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720
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Antonucci J, Wallace M, Goldstein N, Kestin L, Chen P, Gilbert S, Kunzman J, Benitez P, Martinez A, Vicini F. 2003. Int J Radiat Oncol Biol Phys 2006. [DOI: 10.1016/j.ijrobp.2006.07.405] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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721
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Chan K, Chen P, Xie Z, Kulp S, Chen C, Covey J. 602 POSTER Pharmacokinetics of Akt inhibitor NSC 728209 in the rat by LC/MS/MS method. EJC Suppl 2006. [DOI: 10.1016/s1359-6349(06)70607-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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722
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Cheng J, Chou C, Lee P, Cheng A, Hsu H, Chen P. 2699. Int J Radiat Oncol Biol Phys 2006. [DOI: 10.1016/j.ijrobp.2006.07.1115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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723
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Chen K, Yu C, Chen P, Cheng A. 485 POSTER The inhibition of P13K/Akt pathway as a major molecular determinant of bortezomib-induced apoptosis in hepatocellular carcinoma cells. EJC Suppl 2006. [DOI: 10.1016/s1359-6349(06)70490-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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724
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Kestin L, Vicini F, Brabbins D, Ghilezan M, Gustafson G, Chen P, Yan D, Martinez A. 2248. Int J Radiat Oncol Biol Phys 2006. [DOI: 10.1016/j.ijrobp.2006.07.655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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725
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Yang H, Reheman A, Chen P, Zhu G, Hynes RO, Freedman J, Wagner DD, Ni H. Fibrinogen and von Willebrand factor-independent platelet aggregation in vitro and in vivo. J Thromb Haemost 2006; 4:2230-7. [PMID: 16824188 DOI: 10.1111/j.1538-7836.2006.02116.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND Fibrinogen (Fg) has been considered essential for platelet aggregation. However, we recently demonstrated formation of occlusive thrombi in Fg-deficient mice and in mice doubly deficient for Fg and von Willebrand factor (Fg/VWF(-/-)). METHODS AND RESULTS Here we studied Fg/VWF-independent platelet aggregation in vitro and found no aggregation in citrated platelet-rich plasma of Fg/VWF(-/-) mice. Surprisingly, in Fg/VWF(-/-) plasma without anticoagulant, adenosine diphosphate induced robust aggregation of Fg/VWF(-/-) platelets but not of beta(3)-integrin-deficient (beta(3) (-/-)) platelets. In addition, beta(3) (-/-) platelets did not significantly incorporate into thrombi in Fg/VWF(-/-) mice. This Fg/VWF-independent aggregation was blocked by thrombin inhibitors (heparin, hirudin, PPACK), and thrombin or thrombin receptor activation peptide (AYPGKF-NH(2)) induced aggregation of gel-filtered Fg/VWF(-/-) platelets in 1 mm Ca(2+) PIPES buffer. Notably, aggregation in PIPES buffer was only 50-60% of that observed in Fg/VWF(-/-) plasma. Consistent with the requirement for thrombin in vitro, hirudin completely inhibited thrombus formation in Fg/VWF(-/-) mice. These data define a novel pathway of platelet aggregation independent of both Fg and VWF. Although this pathway was not detected in the presence of anticoagulants, it was observed under physiological conditions in vivo and in the presence of Ca(2+)in vitro. CONCLUSIONS beta(3) integrin, thrombin, and Ca(2+) play critical roles in this Fg/VWF-independent aggregation, and both plasma and platelet granule proteins contribute to this process.
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