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Li L, Bryant D, Van Heugten T, Bos PJ. Near-diffraction-limited and low-haze electro-optical tunable liquid crystal lens with floating electrodes. OPTICS EXPRESS 2013; 21:8371-8381. [PMID: 23571926 DOI: 10.1364/oe.21.008371] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A near-diffraction-limited, low-haze and tunable liquid crystal (LC) lens is presented. Building on an understanding of the key factors that have limited the performance of lenses based on liquid crystals, we show a simple design whose optical quality is similar to a high quality glass lens. It uses 'floating' electrodes to provide a smooth, controllable applied potential profile across the aperture to manage the phase profile.
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Li L, Bryant D, van Heugten T, Bos PJ. Physical limitations and fundamental factors affecting performance of liquid crystal tunable lenses with concentric electrode rings. APPLIED OPTICS 2013; 52:1978-1986. [PMID: 23518745 DOI: 10.1364/ao.52.001978] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 02/11/2013] [Indexed: 06/01/2023]
Abstract
A comprehensive analysis of fundamental factors and their effects on the performance of liquid crystal (LC)-based lenses is given. The analysis adopts numerical LC director and electric field simulation, as well as scalar diffraction theory for calculating the lens performance considering different variable factors. A high-efficiency LC lens with concentric electrode rings is fabricated for verifying and enriching the analysis. The measurement results are in close agreement with the analysis, and a summary of key factors is given with their quantitative contributions to the efficiency.
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Bourdeaux C, Thomas M, Gould T, Evans Z, Bryant D. Validation of a computerised system to calculate the sequential organ failure assessment score. Crit Care 2010. [PMCID: PMC2934079 DOI: 10.1186/cc8477] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Breeze J, Bryant D. Current Concepts in the Epidemiology and Management of Battlefield Head, Face and Neck trauma. J ROY ARMY MED CORPS 2009; 155:274-8. [DOI: 10.1136/jramc-155-04-07] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Grubbs SS, Gonzalez M, Krasna M, Siegel R, Bryant D, Tschetter L, Hayenga L, Duggan B, St. Germaine D, Denicoff A. Tracking clinical trial accrual strategies and barriers via a Web-based screening tool. J Clin Oncol 2009. [DOI: 10.1200/jco.2009.27.15_suppl.6586] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
6586 Background: The National Cancer Institute Community Cancer Centers Program (NCCCP) has developed a web based tracking tool to monitor screening of patients for clinical trial participation. The system is designed to collect data from multiple research sites throughout the geographically diverse group. The log blindly collects patient demographics, successful trial entry, and reasons for trial enrollment failure. Methods: Seven NCCCP sites utilized the log during the 60 day open accrual period for the Wake Forrest WFU 07–02–03 cancer control trial (chronic lymphocytic leukemia COLD- fX) in Novermber 2008 and December 2008. Results: 327 chronic lymphocytic leukemia patients were screened mostly by chart review. 162 (50%) were eligible for study entry. 45 (14%) entered the trial. 103 (31%) eligible patients declined entry. Of the 103, 72 (70%) did not wish to participate in research, 15 (15%) had travel constraints, 5 (5%) perceived excess toxicity, 9 (9%) gave no reason. 14 (3%) eligible had their physician decline entry. Overall, 28% of eligible patients entered the trial. 165 (50%) were trial ineligible. 82 (50%) for prior therapy, 30 (18%) for co morbid conditions, 10 (6%) missed an entry time requirement, 39 (24%) have incomplete data. Conclusions: The NCCCP trial screening log successfully captures real time clinical trial participation data from a diverse network of clinical trial sites. This data base will allow future analysis of individual clinical trial and site accrual barriers and empower strategies to increase trial participation. No significant financial relationships to disclose.
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Hunt MA, Birmingham TB, Bryant D, Jones I, Giffin JR, Jenkyn TR, Vandervoort AA. Lateral trunk lean explains variation in dynamic knee joint load in patients with medial compartment knee osteoarthritis. Osteoarthritis Cartilage 2008; 16:591-9. [PMID: 18206395 DOI: 10.1016/j.joca.2007.10.017] [Citation(s) in RCA: 158] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2007] [Accepted: 10/29/2007] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To test the hypothesis that selected gait kinematics, particularly lateral trunk lean, observed in patients with medial compartment knee osteoarthritis explain variation in dynamic knee joint load. METHOD In this cross-sectional observational study, 120 patients with radiographically confirmed varus gonarthrosis underwent three-dimensional gait analysis at their typical walking speed. We used sequential (hierarchical) linear regression to examine the amount of variance in dynamic knee joint load (external knee adduction moment) explained by static lower limb alignment (mechanical axis angle) and gait kinematics determined a priori based on their proposed effect on knee load (walking speed, toe-out angle, and lateral trunk lean angle). RESULTS Approximately 50% of the variation in the first peak external knee adduction moment was explained by mechanical axis angle (25%), Western Ontario and McMaster Universities Osteoarthritis Index pain score (1%), gait speed (1%), toe-out angle (12%), and lateral trunk lean angle (13%). There was no confounding or interaction with Kellgren and Lawrence grade of severity. CONCLUSIONS Gait kinematics, particularly lateral trunk lean, explain substantial variation in dynamic knee joint load in patients with medial compartment knee osteoarthritis. While largely ignored in previous gait studies, the effect of lateral trunk lean should be considered in future research evaluating risk factors and interventions for progression of knee osteoarthritis.
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Vist GE, Hagen KB, Devereaux PJ, Bryant D, Kristoffersen DT, Oxman AD. Outcomes of patients who participate in randomised controlled trials compared to similar patients receiving similar interventions who do not participate. Cochrane Database Syst Rev 2007:MR000009. [PMID: 17443630 DOI: 10.1002/14651858.mr000009.pub3] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Some people believe that patients who take part in randomised controlled trials (RCTs) face risks that they would not face if they opted for non-trial treatment. Others think that trial participation is beneficial and the best way to ensure access to the most up to date physicians and treatments. OBJECTIVES To assess the effects of patient participation in RCTs ('trial effects') independent both of the effects of the clinical treatments being compared ('treatment effects') and any differences between patients who participated in RCTs and those who did not. SEARCH STRATEGY In May 2001, we searched The Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, The Cochrane Methodology Register, SciSearch and PsycINFO for potentially relevant studies. Our search yielded over 10,000 references. In addition, we reviewed the reference lists of relevant articles and wrote to over 250 investigators to try to obtain further information. SELECTION CRITERIA Randomised studies and cohort studies with data on clinical outcomes of RCT participants and similar patients who received similar treatment outside of RCTs. DATA COLLECTION AND ANALYSIS At least two reviewers independently assessed studies for inclusion, assessed study quality and extracted data. Study authors were contacted for additional information. MAIN RESULTS We included five randomised studies (yielding 6 comparisons) and 50 non-randomised cohort studies (85 comparisons), with 31,140 patients treated in RCTs and 20,380 patients treated outside RCTs. In the randomised studies, patients were invited to participate in an RCT or not; these comparisons provided limited information because of small sample sizes (a total of 412 patients) and the nature of the questions they addressed. There was statistically significant heterogeneity (P < 0.002, I(2) = 36.2%) among the 73 dichotomous outcome comparisons; none of the potential explanatory factors we investigated helped to explain this heterogeneity. No statistically significant differences were found for 63 of the 73 comparisons. Eight comparisons reported statistically significant better outcomes for patients treated within RCTs, and two comparisons reported statistically significant worse outcomes for patients treated within RCTs. There were no statistically significant differences in heterogeneity (P = 0.53, I(2) = 0%) or in outcomes (SMD 0.01, 95% CI -0.10 to 0.12) of patients treated within and outside RCTs in the 18 comparisons which had used continuous outcomes. AUTHORS' CONCLUSIONS This review indicates that participation in RCTs is not associated with greater risks than receiving the same treatment outside RCTs. These results challenge the assertion that the results of RCTs are not applicable to usual practice.
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Vist GE, Hagen KB, Devereaux PJ, Bryant D, Kristoffersen DT, Oxman AD. Outcomes of patients who participate in randomised controlled trials compared to similar patients receiving similar interventions who do not participate. THE COCHRANE DATABASE OF SYSTEMATIC REVIEWS 2004. [DOI: 10.1002/14651858.mr000009.pub2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Burns A, Bryant D, Clark S. An aid to accurate skin closure. Laryngoscope 2002; 112:412-3. [PMID: 11889409 DOI: 10.1097/00005537-200202000-00041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Charlwood J, Bryant D, Skehel JM, Camilleri P. Analysis of N-linked oligosaccharides: progress towards the characterisation of glycoprotein-linked carbohydrates. BIOMOLECULAR ENGINEERING 2001; 18:229-40. [PMID: 11911090 DOI: 10.1016/s1389-0344(01)00098-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The covalent attachment of carbohydrate to proteins is a very common co- or post-translational event in the biosynthesis of glycoproteins. The type and heterogeneity of these oligosaccharides can affect a range of physico-chemical and biological properties of a glycoprotein. Thus the development of sensitive, reliable and robust analytical methods for carbohydrate analysis is important in the pharmaceutical industry, especially in the recombinant production of experimental and therapeutic glycoproteins. In this report we have reviewed methodology for the in-gel enzymatic release of N-linked oligosaccharides from glycoproteins separated by electrophoresis. These oligosaccharides are derivatised by reductive amination using 3-acetamido-6-aminoacridine (AA-Ac), a novel, highly fluorescent probe. A major advantage of this technique is that glycan derivatives are amenable to analysis by an array of chromatographic and mass spectrometric methods, allowing the resolution and characterisation of a wide variety of glycan structures. It is hoped that in due course the methodology described will be applied to proteomics studies, especially in identifying the role of carbohydrate in protein function and disease.
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Willoughby M, Kupersmidt J, Bryant D. Overt and covert dimensions of antisocial behavior in early childhood. JOURNAL OF ABNORMAL CHILD PSYCHOLOGY 2001; 29:177-87. [PMID: 11411781 DOI: 10.1023/a:1010377329840] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The present study was designed to assess both the prevalence and structure of antisocial behavior in a normative sample of preschoolers. Prevalence estimates suggested that 40% of preschoolers exhibit at least one antisocial behavior each day. Furthermore, 10% of preschoolers exhibit six or more antisocial behaviors each day. Consistent with research based on older children, factor analyses provided support for conceptualizing antisocial behavior in early childhood as consisting of both overt and covert dimensions. While both overt and covert behaviors had acceptable test-retest reliability, only overt behaviors had acceptable interrater reliability. Finally both overt and covert dimensions of antisocial behavior were uniquely related to general measures of conduct problems, hyperactivity, and adult and peer conflict in the classroom setting. Findings are discussed with regard to early assessment and the developmental course of antisocial behavior.
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Sankoff D, Bryant D, Deneault M, Lang BF, Burger G. Early eukaryote evolution based on mitochondrial gene order breakpoints. J Comput Biol 2001; 7:521-35. [PMID: 11108477 DOI: 10.1089/106652700750050925] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The comparison of the gene orders in a set of genomes can be used to infer their phylogenetic relationships and to reconstruct ancestral gene orders. For three genomes this is done by solving the "median problem for breakpoints"; this solution can then be incorporated into a routine for estimating optimal gene orders for all the ancestral genomes in a fixed phylogeny. For the difficult (and most prevalent) case where the genomes contain partially different sets of genes, we present a general heuristic for the median problem for induced breakpoints. A fixed-phylogeny optimization based on this is applied in a phylogenetic study of a set of completely sequenced protist mitochondrial genomes, confirming some of the recent sequence-based groupings which have been proposed and, conversely, confirming the usefulness of the breakpoint method as a phylogenetic tool even for small genomes.
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Morrow DG, Menard WE, Stine-Morrow EA, Teller T, Bryant D. The influence of expertise and task factors on age differences in pilot communication. Psychol Aging 2001; 16:31-46. [PMID: 11302366 DOI: 10.1037/0882-7974.16.1.31] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The influence of expertise and task factors on age differences in a simulated pilot-Air Traffic Control (ATC) communication task was examined. Young, middle-aged, and older pilots and nonpilots listened to ATC messages that described a route through an airspace, during which they referred to a chart of this airspace. Participants read back each message and then answered a probe question about the route. It was found that pilots read back messages more accurately than nonpilots, and younger participants were more accurate than older participants. Age differences were not reduced for pilots. Pilots and younger participants also answered probes more accurately, suggesting that they were better able to interpret the ATC messages in terms of the chart in order to create a situation model of the flight. The findings suggest that expertise benefits occur for adults of all ages. High levels of flying experience among older pilots (as compared with younger pilots) helped to buffer age-related declines in cognitive resources, thus providing evidence for the mediating effects of experience on age differences.
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Sorokin Y, Blackwell S, Reinke T, Kazzi N, Berman S, Bryant D. Demographic and intrapartum characteristics of term pregnancies with early-onset neonatal seizures. J Perinatol 2001; 21:90-2. [PMID: 11324366 DOI: 10.1038/sj.jp.7200499] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE To compare the demographic and intrapartum factors of term pregnancies in which early-onset neonatal seizures developed with the characteristics of a large, unselected control population. STUDY DESIGN Pregnancies delivered at term (gestational age > or = 37 weeks) in one birthing unit between 1984 and 1995 with a discharge diagnosis of neonatal seizures were identified. Maternal and neonatal charts of these patients were reviewed to confirm the diagnosis of early-onset seizure (EOS) which was defined as a clinical or EEG-diagnosed seizure within 72 hours of life. Demographic and intrapartum factors were compared between these EOS cases and all singleton term pregnancies delivered over the same time period in which there was no EOS. A regression model was then developed to determine factors predictive of EOS. RESULTS Of 80,561 total deliveries during the 11-year study period, there were 64,340 control and 62 EOS (0.1%) deliveries. Regression modeling identified NICU admission, depressed 1- and 5-minute Apgar scores, and neonatal intubation as predictors of EOS, but not operative vaginal, vaginal breech, or cesarean delivery. CONCLUSION Depressed condition at birth and/or the requirement for NICU care was the most important risk associated with early seizures in term infants.
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Buchman AL, Sohel M, Moukarzel A, Bryant D, Schanler R, Awal M, Burns P, Dorman K, Belfort M, Jenden DJ, Killip D, Roch M. Plasma choline in normal newborns, infants, toddlers, and in very-low-birth-weight neonates requiring total parenteral nutrition. Nutrition 2001; 17:18-21. [PMID: 11165882 DOI: 10.1016/s0899-9007(00)00472-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Choline deficiency is associated with hepatic abnormalities in adult volunteers and patients administered total parenteral nutrition (TPN). Preliminary investigation has suggested that plasma-free choline concentration (PFCh) is greater in neonatal animals, including humans, than in adults. The aims of this study were to determine the normal PFCh and phospholipid-bound choline concentration (PPLBCh) for newborns, infants, and toddlers and to determine the change during TPN. We also sought to determine the degree of fetal choline extraction, the relation between maternal and newborn plasma choline concentrations, and the relation between plasma choline status and normal newborn length, weight, and gestational age. Blood samples were obtained from 104 full-term newborns in two centers (Ben Taub and Maimonides), 25 mothers, 21 normal infants aged 20.3 +/- 11.8 wk, 12 normal infants aged 62.4 +/- 3.9 wk, and 14 preterm infants (gestational age = 28.9 +/- 2.2 wk) who required TPN. The vein PFChs were 28.1 +/- 13.0 nmol/mL (Ben Taub) and 68.1 +/- 16.9 nmol/mL (Maimonides). The artery PFChs were 27.1 +/- 13.0 nmol/mL (Ben Taub) and 57.9 +/- 11.6 nmol/mL (Maimonides). The vein PPLChs were 1004.7 +/- 246.6 nmol/mL (Ben Taub) and 1121.2 +/- 289.6 nmol/mL (Maimonides). The artery PPLChs were 1065.7 +/- 469.3 nmol/mL (Ben Taub) and 1106.9 +/- 285.8 nmol/mL (Maimonides). The vein-minus-artery differences for PFCh were 1.0 +/- 9.7 nmol/mL (Ben Taub) and 10.2 +/- 10.9 nmol/mL (Maimonides). The vein-minus-artery differences for PPLCh were -51.9 +/- 398.2 nmol/mL (Ben Taub General Hospital, Houston, Texas) and 14.4 +/- 254.3 nmol/mL (Maimonides, New York, New York). Maternal venous PFCh was 8.4 +/- 3.1 nmol/mL. Maternal venous PPLCh was 2592.1 +/- 584.0 nmol/mL (range = 1227.8-3729.0). Maternal venous PFCh correlated with newborn arterial PFCh (r = 0.53, P < 0.05) but not with newborn venous PFCh. No correlation was seen between maternal venous and newborn PPLCh. No significant differences were seen in PPLCh or choline extraction in Ben Taub versus Maimonides patients, although PFCh was significantly greater in the newborns from Maimonides (P < 0.05). The mean venous PFCh and PPLCh in the preterm infants before beginning TPN was 21.2 +/- 6.3 and 1366.8 +/- 339.1 nmol/mL, respectively. Just before initiation of tube feeding (4.0 +/- 2.7 d after TPN had been started), mean venous PFCh and PPLCh was 18.4 +/- 5.3 and 2251.8 +/- 686.9 nmol/mL, respectively. When TPN was discontinued and tube feeding increased to goal, after 10.8 +/- 10.4 d, venous PFCh and PPLCh was 22.6 +/- 8.7 and 2072.5 +/- 540.6 nmol/mL, respectively. Venous PFCh and PPLCh was 13.4 +/- 2.5 and 1827.5 +/- 327.0 nmol/mL, respectively in the older infant group. In conclusion, newborn PFCh is significantly greater than PFCh in adults but falls to adult levels within the first year of life. Low maternal PFCh may be associated with low newborn PFCh. Normal newborn plasma choline status has no bearing on intrauterine growth, although the role of maternal choline deficiency in underweight newborns is unknown. Newborn PPLCh is substantially below that of adults, which suggests its use in membrane synthesis during growth.
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Bryant D, Fleischer I. Changing an ostomy appliance. Nursing 2000; 30:51-3. [PMID: 11111656 DOI: 10.1097/00152193-200030110-00024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Malin DH, Lake JR, Moon WD, Moy D, Montellano AL, Moy E, Campbell TD, Bell MV, Bryant D, Harrison LM, Grandy DK. Nociceptin/orphanin FQ (N/OFQ) induces a quasi-morphine abstinence syndrome in the rat. Psychopharmacology (Berl) 2000; 151:344-50. [PMID: 11026741 DOI: 10.1007/s002130000473] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Nociceptin/orphanin FQ (N/OFQ) is a neuropeptide that exerts antiopiate effects under some circumstances, and there is evidence that it contributes to opiate tolerance. This raises the question, might N/OFQ also contribute to opiate dependence and abstinence? Twenty-two male Sprague-Dawley rats were cannulated in the third ventricle and challenged 7 days later by third ventricle injection of 50, 200 or 1,000 ng N/OFQ or saline alone. Each rat was observed under "blind" conditions for 30 min beginning 15 min after onset of the third ventricle injection. There was a significant positive linear trend of signs as a function of N/OFQ dose. Subjects receiving saline had 18.0+/-2.0 (mean+/-SEM) overall abstinence-like signs, whereas subjects receiving 50, 200 or 1000 ng N/OFQ had 35.2+/-3.6, 49.8+/-2.6 and 63.5+/-9.7 signs, respectively. In 16 additional rats, abstinence-like signs induced by 1000 ng N/OFQ were significantly attenuated by low SC doses of morphine or clonidine. These results raise the possibility that N/OFQ might contribute to opiate dependence and subsequent abstinence syndrome. On the other hand, N/OFQ over a wide dose range induced abstinence signs with similar potency in morphine dependent and non-dependent rats.
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Virmani AK, Rathi A, Zöchbauer-Müller S, Sacchi N, Fukuyama Y, Bryant D, Maitra A, Heda S, Fong KM, Thunnissen F, Minna JD, Gazdar AF. Promoter methylation and silencing of the retinoic acid receptor-beta gene in lung carcinomas. J Natl Cancer Inst 2000; 92:1303-7. [PMID: 10944551 DOI: 10.1093/jnci/92.16.1303] [Citation(s) in RCA: 270] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Retinoic acid plays an important role in lung development and differentiation, acting primarily via nuclear receptors encoded by the retinoic acid receptor-beta (RARbeta) gene. Because receptor isoforms RARbeta2 and RARbeta4 are repressed in human lung cancers, we investigated whether methylation of their promoter, P2, might lead to silencing of the RARbeta gene in human lung tumors and cell lines. METHODS Methylation of the P2 promoter from small-cell lung cancer (SCLC) and non-small-cell lung cancer (NSCLC) cell lines and tumor samples was analyzed by the methylation-specific polymerase chain reaction (PCR). Expression of RARbeta2 and RARbeta4 was analyzed by reverse transcription-PCR. Loss of heterozygosity (LOH) was analyzed by PCR amplification followed by electrophoretic separation of PCR products. Statistical differences were analyzed by Fisher's exact test with continuity correction. RESULTS The P2 promoter was methylated in 72% (63 of 87) of SCLC and in 41% (52 of 127) of NSCLC tumors and cell lines, and the difference was statistically significant (two-sided P:<.001). By contrast, in 57 of 58 control samples, we observed only the unmethylated form of the gene. Four tumor cell lines with unmethylated promoter regions expressed both RARbeta2 and RARbeta4. Four tumor lines with methylated promoter regions lacked expression of these isoforms, but demethylation by exposure to 5-aza-2'-deoxycytidine restored their expression. LOH at chromosome 3p24 was observed in 100% (13 of 13) of SCLC lines and 67% (12 of 18) of NSCLC cell lines, and the difference was statistically significant (two-sided P: =.028). CONCLUSIONS Methylation of the RARbeta P2 promoter is one mechanism that silences RARbeta2 and RARbeta4 expression in many lung cancers, particularly SCLC. Chemical demethylation is a potential approach to lung cancer therapy.
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Bhaya D, Bianco NR, Bryant D, Grossman A. Type IV pilus biogenesis and motility in the cyanobacterium Synechocystis sp. PCC6803. Mol Microbiol 2000; 37:941-51. [PMID: 10972813 DOI: 10.1046/j.1365-2958.2000.02068.x] [Citation(s) in RCA: 163] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We have recently shown that phototactic movement in the unicellular cyanobacterium Synechocystis sp. PCC6803 requires type IV pilins. To elucidate further type IV pilus-dependent motility, we inactivated key genes implicated in pilus biogenesis and function. Wild-type Synechocystis sp. PCC6803 cells have two morphologically distinct pilus types (thick and thin pili). Of these, the thick pilus morphotype, absent in a mutant disrupted for the pilin-encoding pilA1 gene, appears to be required for motility. The thin pilus morphotype does not appear to be altered in the pilA1 mutant, raising the possibility that thin pili have a function distinct from that of motility. Mutants disrupted for pilA2, which encodes a second pilin-like protein, are still motile and exhibit no difference in morphology or density of cell-surface pili. In contrast, inactivation of pilD (encoding the leader peptidase) or pilC (encoding a protein required for pilus assembly) abolishes cell motility, and both pilus morphotypes are absent. Thus, the PilA1 polypeptide is required for the biogenesis of the thick pilus morphotype which, in turn, is necessary for motility (hence we refer to them as type IV pili). Furthermore, PilA2 is critical neither for motility nor for pilus biogenesis. Two genes encoding proteins with similarity to PilT, which is considered to be a component of the motor essential for type IV pilus-dependent movement, were also inactivated. A pilT1 mutant is (i) non-motile, (ii) hyperpiliated and (iii) accumulates higher than normal levels of the pilA1 transcript. In contrast, pilT2 mutants are motile, but are negatively phototactic under conditions in which wild-type cells are positively phototactic.
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Thompson M, Kliewer A, Maass D, Becker L, White DJ, Bryant D, Arteaga G, Horton J, Giroir BP. Increased cardiomyocyte intracellular calcium during endotoxin-induced cardiac dysfunction in guinea pigs. Pediatr Res 2000; 47:669-76. [PMID: 10813595 DOI: 10.1203/00006450-200005000-00019] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Septic shock is a complex pathophysiologic state characterized by circulatory insufficiency, multiple system organ dysfunction, and frequent mortality. Although profound cardiac dysfunction occurs during sepsis, the pathogenesis of this dysfunction remains poorly understood. To determine whether abnormalities in intramyocyte calcium accumulation might contribute to the development of cardiac dysfunction, we measured myocyte intracellular calcium during peak cardiac dysfunction after an endotoxin challenge. Intraperitoneal administration of Escherichia coli lipopolysaccharide 4 mg/kg to adult guinea pigs resulted in significantly impaired cardiac performance (Langendorff preparation) 18 h after challenge compared with control. This included diminished left ventricular pressure development (56 +/- 7 versus 95 +/- 4 mm Hg, p < 0.05), maximal rate of left ventricular pressure rise (998 +/- 171 versus 1784 +/- 94 mm Hg/s, p < 0.05) and left ventricular pressure fall (1014 +/- 189 versus 1621 +/- 138 mm Hg/s, p < 0.05). Assay of intracellular calcium in fura-2AM-loaded cardiac myocytes demonstrated increased intracellular calcium concentration in myocytes obtained from lipopolysaccharide-challenged animals compared with controls (234 +/- 18 versus 151 +/- 6 nM, p < 0.05). Inhibition of calcium-release channel (ryanodine receptor) opening by administration of dantrolene prevented the increase in intracytoplasmic calcium (159 +/- 8 versus 234 +/- 18 nM, p < 0.05) and partially ameliorated systolic and diastolic ventricular dysfunction. These data indicate that abnormalities of intracellular calcium contribute to the development of endotoxin-induced myocardial dysfunction.
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Burchinal MR, Roberts JE, Riggin R, Zeisel SA, Neebe E, Bryant D. Relating quality of center-based child care to early cognitive and language development longitudinally. Child Dev 2000; 71:339-57. [PMID: 10834469 DOI: 10.1111/1467-8624.00149] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
How quality of center-based child care relates to early cognitive and language development was examined longitudinally from 6 to 36 months of age in a sample of 89 African American children. Both structural and process measures of quality of child care were collected through observation of the infant classroom. Results indicated that higher quality child care was related to higher measures of cognitive development (Bayley Scales of Infant Development), language development (Sequenced Inventory of Communication Development), and communication skills (Communication and Symbolic Behavior Scales) across time, even after adjusting for selected child and family characteristics. In addition, classrooms that met professional recommendations regarding child:adult ratios tended to have children with better language skills. Classrooms that met recommendations regarding teacher education tended to have girls with better cognitive and receptive language skills. These findings, in conjunction with the growing child-care literature, provide further evidence that researchers and policymakers should strive to improve the quality of child care to enhance early development of such vulnerable children.
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Maitra A, Tavassoli FA, Albores-Saavedra J, Behrens C, Wistuba II, Bryant D, Weinberg AG, Rogers BB, Saboorian MH, Gazdar AF. Molecular abnormalities associated with secretory carcinomas of the breast. Hum Pathol 1999; 30:1435-40. [PMID: 10667421 DOI: 10.1016/s0046-8177(99)90165-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Secretory carcinomas (SCAs) represent a unique histological variant of invasive breast carcinomas, occurring predominantly in patients younger than 30 years of age. Data from limited series have shown SCAs to have a favorable prognosis in patients younger than 20 years of age, whereas the clinical course tends to parallel the more common in filtrating ductal carcinomas (IDCs) in patients older than 20 years. There are no reports on the molecular abnormalities associated with this unusual tumor. Microdissected archival formalin-fixed tissue from 10 SCAs collected from 2 institutions were used to determine the frequencies of allelic loss at 13 chromosomal regions with 19 microsatellite markers, using multiplex polymerase chain reaction (PCR)-based techniques. The results of loss of heterozygosity (LOH) and microsatellite alterations (MAs) analyses were compared with 20 cases of IDCs. P53 gene mutation analysis was also performed on the 10 SCAs using single-strand conformation polymorphism (SSCP) analysis, followed by sequencing of abnormal bands. LOH at multiple regions of chromosome 3p were the most common abnormality in both SCAs (55%) and IDCs (50%), followed by LOH at 17q21 (BRCA1 locus), 13q14 (retinoblastoma gene locus), and 8p21-23. No significant differences were seen in the frequencies of LOH at any chromosomal region except for 17p13 (p53 gene locus), where allelic losses were absent in SCAs, but evident in 46% of IDCs (P < .05). The 2 histological entities were similar in the fractional regional loss (FRL) index (0.26 v 0.24), fractional allelic loss (FAL) index (0.23 v 0.27), as well as in the frequency of MAs (0.015 v 0.005), P > .05. P53 gene missense mutation (G:C::A:T) was detected in 1 of 10(10%) SCAs. Based on the considerable similarities in the molecular abnormalities associated with both tumors, the formation of secondary lumina in both the in situ and the invasive components, as well as suggestions from limited series that the clinical behavior in adult patients parallels that of IDCs, SCA most likely reflects a secretory variant of IDCs.
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MESH Headings
- Adult
- Aged
- Alleles
- Breast Neoplasms/genetics
- Breast Neoplasms/metabolism
- Breast Neoplasms/therapy
- Carcinoma, Ductal, Breast/genetics
- Chromosomes, Human, Pair 13
- Chromosomes, Human, Pair 3
- Chromosomes, Human, Pair 8
- Female
- Genes, p53
- Humans
- Loss of Heterozygosity
- Microsatellite Repeats
- Middle Aged
- Mutation
- Polymerase Chain Reaction
- Polymorphism, Single-Stranded Conformational
- Prognosis
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Wistuba II, Bryant D, Behrens C, Milchgrub S, Virmani AK, Ashfaq R, Minna JD, Gazdar AF. Comparison of features of human lung cancer cell lines and their corresponding tumors. Clin Cancer Res 1999; 5:991-1000. [PMID: 10353731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Although human lung tumor-derived cell lines play an important role in the investigation of lung cancer biology and genetics, there is no comprehensive study comparing the genotypic and phenotypic properties of lung cancer cell lines with those of the individual tumors from which they were derived. We compared a variety of properties of 12 human non-small cell lung carcinoma (NSCLC) cell lines (cultured for a median period of 39 months; range, 12-69) and their corresponding archival tumor tissues. There was, in general, an excellent concordance between the lung tumor cell lines and their corresponding tumor tissues for morphology (100%), the presence of aneuploidy (100%), immunohistochemical expression of HER2/neu (100%) and p53 proteins (100%), loss of heterozygosity at 13 chromosomal regions analyzed (97%) using 37 microsatellite markers, microsatellite alterations (MAs, 75%), TP53 (67%), and K-ras (100%) gene mutations. In addition, there was 100% concordance for the parental allele lost in all 115 comparisons of allelic losses. Some discrepancies were found; more aneuploid subpopulations of cells were detected in the cell lines as well as higher incidences of TP53 mutations (4 of 10 mutations not found in the tumors) and microsatellite alterations (two cell lines with MAs not detected in the tumors). Similar loss of heterozygosity frequencies by chromosomal regions and mean fractional allelic loss index were detected between successfully cultured and 40 uncultured lung tumors (0.45 and 0.49, respectively), indicating that both groups were similar. Our findings indicate that the NSCLC cell lines in the large majority of instances retain the properties of their parental tumors for lengthy culture periods. NSCLC cell lines appear very representative of the lung cancer tumor from which they were derived and thus provide suitable model systems for biomedical studies of this important neoplasm.
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Bickman L, Summerfelt WT, Bryant D. The quality of services in a children's mental health managed care demonstration. JOURNAL OF MENTAL HEALTH ADMINISTRATION 1999; 23:30-9. [PMID: 10154317 DOI: 10.1007/bf02518641] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The Fort Bragg Demonstration and evaluation was designed to test the cost-effectiveness of a continuum of care model of service delivery for children and adolescents. A crucial aspect of the evaluation was the measurement of the quality of services provided in the Demonstration. Two key service components were examined: intake assessment and case management. It was concluded that these key components of the continuum of care were implemented with sufficient quality to have the theoretically predicted effects on mental health.
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