51
|
Xu G, Li LP, Liu F, Pei D, Wang S, Pang D, Borukhson L, Nandagudi A, Jawad A, Campbell RC, Scott DL, Kiely P, Gordon PA, Campbell RC, Rafferty G, Scott DL, Reilly C, Ward K, Gordon PA, Charles PJ, Paterson E, Ekholm L, Putova I, Danko K, Lundberg I, Vencovsky J, Chinoy H, Lundberg IE, Vencovsky J, Danko K, Vincze M, Lund Hetland M, Cooper RG, Ohtamaa M, Steen Krogh N. Muscle disorders: 67. Influence of Occupational Factors on Regional Musculoskeletal Disorders in Coal Miners. Rheumatology (Oxford) 2011. [DOI: 10.1093/rheumatology/ker041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
52
|
Xu G, Li LP, Liu F, Pei D, Sheng W, Pang D, Liu F, Li LP, Xu G, Wang S, Pang D, Camacho EM, Harrison MJ, Verstappen SM, Bunn DK, Symmons D. Epidemiology: 46. Low Back Pain and Occupational Risk Factors Among Coal Miners in China. Rheumatology (Oxford) 2011. [DOI: 10.1093/rheumatology/ker038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
53
|
Schupf N, Zigman WB, Tang MX, Pang D, Mayeux R, Mehta P, Silverman W. Change in plasma Aß peptides and onset of dementia in adults with Down syndrome. Neurology 2010; 75:1639-44. [PMID: 21041786 DOI: 10.1212/wnl.0b013e3181fb448b] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To examine changes in levels of plasma amyloid-β (Aβ) peptides, Aβ42 and Aβ40, in relation to onset of Alzheimer disease (AD) in adults with Down syndrome (DS). METHODS Plasma Aβ42 and Aβ40 were measured at initial examination and at follow-up in a community-based cohort of 225 adults with DS who did not have dementia at baseline and were assessed for cognitive/functional abilities and health status and followed at 14- to 20-month intervals. We used Cox proportional hazards modeling to estimate the cumulative incidence of AD by Aβ peptide change group (increasing, no change, or decreasing), adjusting for covariates. RESULTS Sixty-one (27.1%) of the participants developed AD. At follow-up, a decrease in Aβ42 levels, a decrease in the Aβ42/Aβ40 ratio, and an increase in Aβ40 levels were related to conversion to AD. Compared with the group with increasing levels of Aβ42, the likelihood of developing AD was 5 times higher for those whose plasma Aβ42 levels decreased over follow-up (hazard ratio [HR] = 4.9, 95% confidence interval [CI] 2.1-11.4). Decreasing Aβ42/Aβ40 was also strongly related to AD risk (HR = 4.9, 95% CI 1.8-13.2), while decreasing Aβ40 was associated with lower risk (HR = 0.4, 95% CI 0.2-0.9). CONCLUSIONS Among adults with DS, decreasing levels of plasma Aβ42, a decline in the Aβ42/Aβ40 ratio, or increasing levels of Aβ40 may be sensitive indicators of conversion to AD, possibly reflecting compartmentalization of Aβ peptides in the brain.
Collapse
|
54
|
Pang D, Jones GT, Power C, Macfarlane GJ. Influence of childhood behaviour on the reporting of chronic widespread pain in adulthood: results from the 1958 British Birth Cohort Study. Rheumatology (Oxford) 2010; 49:1882-8. [DOI: 10.1093/rheumatology/keq052] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
|
55
|
Lei S, Harter W, Collins S, Xia F, Pang D, Gagnon G. SU-FF-T-111: Head-And-Neck IMRT Without Beam-Splitting. Med Phys 2009. [DOI: 10.1118/1.3181585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
56
|
Pang D, Evans G, Birch J. Elevated breast cancer risk among mothers of a population-based series of 2668 children with cancer. Ecancermedicalscience 2008; 2:57. [PMID: 22275959 PMCID: PMC3234048 DOI: 10.3332/ecancer.2008.57] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2007] [Indexed: 11/06/2022] Open
Abstract
AIMS Although a previous study found high risk of breast cancer in mothers of children with soft tissue sarcomas, breast cancer risks in mothers of sufferers of other childhood cancers largely remain unknown. The aetiology is not fully understood. The present study explored this excess by varying type of childhood solid cancer and formulated a hypothesis. METHODS Mothers of 2668 children with solid tumours included in the Manchester Children's Tumour Registry, 1954-96, were traced and followed up to 31 December 2000 through the UK National Health Service Central Register. Standardized incidence ratio (SIR), p-values and 95% confidence intervals were calculated from age and calendar-year-specific female breast cancer incidence rates for England and Wales. RESULTS There was a significant excess of breast cancer in mothers overall (SIR=1.3, 95%CI=1.0-1.5) mainly due to mothers of children with rhabdomyosarcoma (RMS) (SIR=2.2, 95%CI=1.0-4.0), skin cancer (SIR=7.9, 95%CI=2.9-17.1) and central nervous system tumours (SIR=1.2, 95%CI=0.9-1.8). Maternal breast cancer risk was associated with late age at birth of the index child, and male sex and young age at diagnosis in the index child. Risk was highest in the ten years, following the birth of the index. The pattern was seen most strongly in mothers of children with embryonal RMS. CONCLUSION There are excesses of breast cancer in mothers of children with solid tumours in general and specifically in RMS, skin and central nervous system (CNS). There appears to be a temporal relationship between certain tumours in children and breast cancer in their mothers, suggesting an origin of their respective pregnancy. We propose a mother-foetal interaction mechanism to explain this association.
Collapse
|
57
|
Birch J, Rowan S, Moran A, Eden T, Pang D. 1400 ORAL Late mortality among five-year survivors of cancer in teenagers and young adults in England. EJC Suppl 2007. [DOI: 10.1016/s1359-6349(07)70739-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
58
|
Pang D, Hethey J, Caulkett NA, Duke T. Partial pressure of end-tidal CO2sampled via an intranasal catheter as a substitute for partial pressure of arterial CO2in dogs. J Vet Emerg Crit Care (San Antonio) 2007. [DOI: 10.1111/j.1476-4431.2007.00213.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
59
|
Pang D, Rodenbush R, Dass K. 2855. Int J Radiat Oncol Biol Phys 2006. [DOI: 10.1016/j.ijrobp.2006.07.1274] [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]
|
60
|
Wickboldt BP, Jones SJ, Marques FC, Pang D, Turner WA, Wetsel AE, Paul W, Chen JH. A study of the properties of hydrogenated amorphous germanium produced by r.f. glow discharge as the electrode gap is varied the link between microstructure and optoelectronic properties. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/13642819108207628] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
61
|
Shang C, Williams T, Pang D. SU-FF-T-72: Absolute Rectal Volumetric Dose as a Meaningful Predictor to Its Late Side Effect in Prostate IMRT. Med Phys 2006. [DOI: 10.1118/1.2240998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
62
|
Pang D, Birch J. 728 Breast cancer incidence among mothers of a population-based series of 2604 children with cancer: evidence of mother-fetal interaction. EJC Suppl 2003. [DOI: 10.1016/s1359-6349(03)90759-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
|
63
|
|
64
|
Pang D, McNally R, Birch JM. Parental smoking and childhood cancer: results from the United Kingdom Childhood Cancer Study. Br J Cancer 2003; 88:373-81. [PMID: 12569379 PMCID: PMC2747546 DOI: 10.1038/sj.bjc.6600774] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
There are strong a priori reasons for considering parental smoking behaviour as a risk factor for childhood cancer but case - control studies have found relative risks of mostly only just above one. To investigate this further, self-reported smoking habits in parents of 3838 children with cancer and 7629 control children included in the United Kingdom Childhood Cancer Study (UKCCS) were analysed. Separate analyses were performed for four major groups (leukaemia, lymphoma, central nervous system tumours and other solid tumours) and more detailed diagnostic subgroups by logistic regression. In the four major groups, after adjustment for parental age and deprivation there were nonsignificant trends of increasing risk with number of cigarettes smoked for paternal preconception smoking and nonsignificant trends of decreasing risk for maternal preconception smoking (all P-values for trend >0.05). Among the diagnostic subgroups, a statistically significant increased risk of developing hepatoblastoma was found in children whose mothers smoked preconceptionally (OR=2.68, P=0.02) and strongest (relative to neither parent smoking) for both parents smoking (OR=4.74, P=0.003). This could be a chance result arising from multiple subgroup analysis. Statistically significant negative trends were found for maternal smoking during pregnancy for all diagnoses together (P<0.001) and for most individual groups, but there was evidence of under-reporting of smoking by case mothers. In conclusion, the UKCCS does not provide significant evidence that parental smoking is a risk factor for any of the major groups of childhood cancers.
Collapse
|
65
|
Kirk KM, Whitfield JB, Pang D, Heath AC, Martin NG. Genetic covariation of neuroticism with monoamine oxidase activity and smoking. AMERICAN JOURNAL OF MEDICAL GENETICS 2001; 105:700-6. [PMID: 11803517 DOI: 10.1002/ajmg.1555] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Variation in the personality trait of neuroticism is known to be affected by genetic influences, but despite a number of association studies, the genes involved have not yet been characterized. In a recent study of platelet monoamine oxidase in 1,551 twin subjects, we found a significant association between monoamine oxidase activity and scores on the Eysenck Personality Questionnaire neuroticism scale. Further analyses presented here indicate that both neuroticism and monoamine oxidase activity are associated with variation in smoking habits, and that adjusting for the effect of smoking strengthens the association between MAO and neuroticism. Analysis of the genetic and environmental sources of covariation between neuroticism, smoking, and monoamine oxidase activity show that approximately 8% of the genetic variance in neuroticism is due to the same additive genetic effects that contribute to variation in monoamine oxidase activity, suggesting that variation in neuroticism is associated in part with aspects of serotonin metabolism.
Collapse
|
66
|
Sun J, Zhang R, Wang Q, Chai L, Pang D, Dai J, Zhang Z, Torizuka K, Nakagawa T, Sugaya T. High-Average-Power Self-Starting Mode-Locked Ti:sapphire Laser With a Broadband Semiconductor Saturable-Absorber Mirror. APPLIED OPTICS 2001; 40:3539-3541. [PMID: 18360381 DOI: 10.1364/ao.40.003539] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We present a novel high-power, self-starting mode-locked Ti:sapphire laser with a semiconductor saturable-absorber mirror as the starter element. This laser, whose slope efficiency is 22%, generates pulses with an average power as high as 1.7 W and a pulse width as short as 16 fs. The self-starting process is also investigated.
Collapse
|
67
|
Abstract
OBJECT The author studied the specific issue of ventral tethering in cases of type II split cord malformation (SCM). He also discussed the issue of ventral tethering in patients with type I SCM in whom a bony septum and dural sleeve have been resected. METHODS Eleven (21%) of 52 patients with type II SCM were found to have a ventral fibrous septum tethering the hemicords to the ventral dura. Four categories of ventral septa were noted: 1) pure ventral intradural septa (three patients); 2) complete dorsoventral intradural septa (three patients); 3) dorsoventral septa continuous with a dermal sinus tract (two patients); and 4) ventral or complete septa continuous with ventral intestinal bands causing intestinal malrotation or diverticulum (three patients). Excluding one autopsy case, all 10 patients had symptoms or progressive neurological syndromes at diagnosis. Magnetic resonance imaging was completely ineffective, and computerized tomography (CT) myelography was only partially effective in detecting ventral tethering in 50% of cases. The only other positive predictor of ventral tethering is the association of dermal sinus tract and intestinal malformations. Combining this predictor with CT myelography, only 60% of the cases of ventral tethering could be suspected before surgery. CONCLUSIONS The author recommends examining all patients with type II SCM, and at surgery the ventral surface of the split length and reunion site should be thoroughly inspected to reveal a ventral band.
Collapse
|
68
|
Pang D, Chasovskikh S, Cohen JS, Obcemea C, Dritschilo A. Atomic force microscopy examination of conformations of polynucleotides in response to platinum isomers: significance of GC content at broken ends. Int J Cancer 2000; 90:68-72. [PMID: 10814956 DOI: 10.1002/(sici)1097-0215(20000420)90:2<68::aid-ijc2>3.0.co;2-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Atomic force microscopy is a technique that enables visualization of macromolecular conformations of polynucleotides at nanometer resolution. We investigated the results of interactions of cisplatin, a DNA binding anticancer drug, and its inactive counterpart, transplatin isomer, on the molecular conformation of polynucleotides: poly d(G-C). poly d(G-C) (polyGC) and poly d(A-T). poly d(A-T) (polyAT). We observed that polyAT exhibited an increased number of enlarged ends of molecules, which we attribute to unwound and/or collapsed regions of polyAT. PolyGC molecules did not show such ends unless cisplatin was added to the PolyGC polymers. Transplatin had the apparent effect of causing overlapping or stacking of the polymer molecules. Addition of exonuclease-III to these polymers removed the visible enlarged ends. The effects of cisplatin as compared to transplatin on the polyGC duplex polymers provide support for the presence of intrastrand covalent linkages, consistent with known N7 guanine interaction of the cis isomer on molecular conformation. Furthermore, our results indicate that the mechanism of interactions of DNA with cisplatin may be dependent on the GC content of the molecules. Int. J. Cancer (Radiat. Oncol. Invest.) 90, 68-72, 2000.
Collapse
|
69
|
Whitfield JB, Pang D, Bucholz KK, Madden PA, Heath AC, Statham DJ, Martin NG. Monoamine oxidase: associations with alcohol dependence, smoking and other measures of psychopathology. Psychol Med 2000; 30:443-454. [PMID: 10824664 DOI: 10.1017/s0033291799001798] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND Many reports have appeared on associations between platelet monoamine oxidase (MAO) activity and susceptibility to psychiatric conditions; principally alcohol dependence but also conduct disorder, other drug use and depression. Recently, it has become apparent that MAO activity is inhibited by some component of cigarette smoke, and smokers have low platelet MAO activity. Since the prevalence of smoking is higher in many of the conditions in which MAO has been implicated, the MAO susceptibility associations may be partly, or entirely, false. METHODS We have measured platelet MAO in 1551 subjects, recruited from the Australian NHMRC Twin Registry, who have provided information on alcohol use and dependence, smoking, conduct disorder, depression, attempted suicide, panic disorder and social phobia. RESULTS Current smoking reduced platelet MAO activity in a significant and dose-related manner, with no evidence of lower MAO in ex-smokers or in non-smoking subjects with co-twins who smoked. Alcohol use and lifetime DSM-III-R alcohol dependence history were not associated with MAO activity when smoking was taken into account. Depression, panic disorder and social phobia showed no significant associations with platelet MAO activity. Subjects with a history of serious attempts at suicide had low platelet MAO activity; but although the difference from controls was as great as the reduction associated with smoking it was not significant after correction for smoking effects. CONCLUSIONS Although synaptic MAO activity undoubtedly plays a role in psychopathology, the concept that platelet MAO activity is a direct genetic marker of vulnerability to alcohol dependence cannot be sustained.
Collapse
|
70
|
Pang D, Tomita T, Byrd S, Conway JJ, Chou P, de Leon GA. A 14-year-Old young woman with a five-week history of back pain. Pediatr Neurosurg 2000; 32:100-8. [PMID: 10838510 DOI: 10.1159/000028908] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
71
|
Cheng ML, Chang SD, Pang D, Adler JR. Intracranial nasal dermoid sinus cyst associated with colloid cyst of the third ventricle. Case report and new concepts. Pediatr Neurosurg 1999; 31:201-6. [PMID: 10705930 DOI: 10.1159/000028862] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A case of a 16-year-old male with both a nasal dermoid sinus cyst (NDSC) and a third ventricle colloid cyst is presented. The NDSC was excised via a single-stage combined intracranial-extracranial approach and the third ventricle colloid cyst was resected endoscopically. The pathogenetic theories of NDSC and third ventricle colloid cyst are discussed, and an embryological explanation for the simultaneous development of the two lesions in this patient is explored. This case is best classified among congenital developmental malformations in a category we propose to call 'anterior neuropore corridor defects.'
Collapse
|
72
|
Choo SJ, McRae G, Olomon JP, St George G, Davis W, Burleson-Bowles CL, Pang D, Luo HH, Vavra D, Cheung DT, Oury JH, Duran CM. Aortic root geometry: pattern of differences between leaflets and sinuses of Valsalva. THE JOURNAL OF HEART VALVE DISEASE 1999; 8:407-15. [PMID: 10461241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
BACKGROUND AND AIMS OF THE STUDY Growing interest in aortic root replacement with the use of stentless auto-, homo- and xenografts, and new developments in aortic valve conservation demand a deeper understanding of the normal aortic root anatomy. METHODS Ten cryopreserved human aortic roots were pressurized, fixed and measured directly (leaflet free edge and attachment) and using three-dimensional computed tomography imaging software (sinus of Valsalva height and volume). RESULTS The mean of the measurements of all four parameters yielded a pattern in which the non-coronary sinus (N) structures had the greatest dimensions followed by the right (R) and then the left (L). Non-parametric ANOVA on each of these parameters also showed significant differences among the sinuses yielding a pattern of N > R > L. This pattern determined an angle of tilt between the plane at the base (annulus) and the plane intersecting the sinotubular junction with a mean value of 11 degrees. Linear regression indicated that this angle did not depend on the size of the base (annulus). CONCLUSIONS The data showed a geometric pattern of the aortic root, with the structures of the non-coronary sinus being the largest followed by the right and then the left. The possible hemodynamic relevance and surgical implications of these findings need to be explored.
Collapse
|
73
|
Allman-Farinelli MA, Hall D, Kingham K, Pang D, Petocz P, Favaloro EJ. Comparison of the effects of two low fat diets with different alpha-linolenic:linoleic acid ratios on coagulation and fibrinolysis. Atherosclerosis 1999; 142:159-68. [PMID: 9920517 DOI: 10.1016/s0021-9150(98)00233-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Fish oils rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been demonstrated to alter coagulation and fibrinolysis variables. This study compared the effects of a traditional cholesterol-lowering diet and a similar diet, which had 50% of the linoleic acid (LA) replaced with the 18 carbon n-3 fatty acid, alpha-linolenic acid (ALA), on selected hemostatic variables. After a 2-week run-in diet with 39.5% total energy (en) from fat, 29 healthy male subjects consumed a 31.5% en fat diet with approximately 7% en from polyunsaturated fat and an ALA:LA ratio of either 1:1.2 (ALA-rich, n=15) or 1:21 (LA-rich, n=14) for 6 weeks. Blood was collected at the beginning, middle and end of test diets for analysis of Factor VIIc and VIIIc, fibrinogen, von Willebrand factor, activated protein C resistance (APC resistance), tissue plasminogen activator and plasminogen activator inhibitor type-1 activities and/or protein concentrations and platelet fatty acids. The ALA-rich diet tripled the percentage of platelet EPA, (P < 0.0005) but had little effect on coagulation and fibrinolysis. The APC ratio demonstrated increased anticoagulant activity on the ALA-rich diet (P < 0.001) only. Studies in patients with vascular pathologies are indicated to corroborate the current findings. Greater ratios of ALA:LA, achievable only with greater amounts of polyunsaturated fat, may be necessary to produce the effects demonstrated after feeding fish oils.
Collapse
|
74
|
Abstract
OBJECTIVE To calculate relative powers for nested case-control studies for different values of both relative risk and numbers of controls per case, given a fixed number of cases available for analysis. METHODS Algebraic and numerical methods. RESULTS In nested case-control studies, statistical power is a function of relative risk, rarity of exposure, number of case-control sets, and the number of controls per case. CONCLUSION The dictum that sufficient power will be obtained in a nested case-control study by selecting only four controls per case cannot be sustained. Appropriate numbers need to be calculated for specific studies.
Collapse
|
75
|
Pang D, Popescu G, Rodgers J, Berman BL, Dritschilo A. Atomic force microscopy investigation of radiation-induced DNA double strand breaks. SCANNING MICROSCOPY 1998; 10:1105-9; discussion 1109-10. [PMID: 9854856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
We have used atomic force microscopy (AFM) to study radiation-induced DNA double strand breaks. Double-stranded plasmid DNA was irradiated with 18-MeV electrons in aqueous buffer, using a medical linear accelerator. Doses of 50, 100, 150, and 200 Gy were delivered to DNA samples, and atomic force microscopy was used to measure the length of each DNA fragment. From these measurements, we obtained the average length of the irradiated DNA for each sample and found a linear-quadratic relationship between the average length and radiation dose.
Collapse
|
76
|
Pang D, Berman BL, Chasovskikh S, Rodgers JE, Dritschilo A. Investigation of neutron-induced damage in DNA by atomic force microscopy: experimental evidence of clustered DNA lesions. Radiat Res 1998. [PMID: 9840180 DOI: 10.2307/3579883] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Using atomic force microscopy (AFM), we have investigated neutron-induced DNA double-strand breaks in plasmids in aqueous solution. AFM permits direct measurement of individual DNA molecules with an accuracy of a few nanometers. Furthermore, the analysis of the DNA fragment size distribution is non-parametric, whereas other methods are dependent on the model. Neutron irradiation of DNA results in the generation of many short fragments, an observation not made for damage induced by low-LET radiation. These data provide clear experimental evidence for the existence of clustered DNA double-strand breaks and demonstrate that short DNA fragments may be produced by such radiations in the absence of a nucleosomal DNA structure.
Collapse
|
77
|
Pang D, Keenan SP, Cook DJ, Sibbald WJ. The effect of positive pressure airway support on mortality and the need for intubation in cardiogenic pulmonary edema: a systematic review. Chest 1998; 114:1185-92. [PMID: 9792593 DOI: 10.1378/chest.114.4.1185] [Citation(s) in RCA: 188] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
OBJECTIVE To critically appraise and summarize the trials examining the addition of continuous positive airway pressure (CPAP) or noninvasive positive pressure ventilation (NPPV) to standard therapy on hospital mortality, need for endotracheal intubation, and predischarge left ventricular function in patients admitted to the hospital with cardiogenic pulmonary edema with gas exchange abnormalities. DATA SOURCES We searched MEDLINE (1983 to June 1997) and bibliographies of all selected articles and review articles. We also reviewed the abstracts from the proceedings of relevant meetings from 1985 to 1997. STUDY SELECTION (1) POPULATION: patients presenting to hospital with cardiogenic pulmonary edema; (2) intervention: one of the following three: (a) the use of CPAP and standard medical therapy vs standard medical therapy alone; (b) the use of NPPV and standard medical therapy vs standard medical therapy alone; and (c) the use of NPPV and standard therapy vs CPAP and standard therapy; (3) outcome: hospital survival, need for endotracheal intubation, or predischarge left ventricular dysfunction; and (4) study design: randomized controlled trial (RCT); if there were fewer than two RCTs, other study designs were included. DATA EXTRACTION Two authors independently extracted data and evaluated the methodologic quality of the studies. DATA SYNTHESIS CPAP was associated with a decrease in need for intubation (risk difference, -26%, 95% confidence intervals, -13 to -38%) and a trend to a decrease in hospital mortality (risk difference, -6.6%; +3 to -16%) compared with standard therapy alone. There was insufficient evidence to comment on the effectiveness of NPPV either compared with standard therapy or CPAP and standard therapy. Evidence was also lacking on the potential for either intervention to cause harm. CONCLUSIONS A modest amount of favorable experimental evidence exists to support the use of CPAP in patients with cardiogenic pulmonary edema. CPAP appears to decrease intubation rates and data suggest a trend toward a decrease in mortality, although the potential for harm has not been excluded. The role of NPPV in this setting requires further study before it can be widely recommended.
Collapse
|
78
|
Choo SJ, Olomon J, Bowles C, Luo HH, Pang D, Oury JH, Duran CM. An in vitro study of the correlation between aortic valve diameter and mitral intertrigonal distance: a simple method to select the correct mitral annuloplasty ring size. THE JOURNAL OF HEART VALVE DISEASE 1998; 7:593-7. [PMID: 9793863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
BACKGROUND AND AIMS OF THE STUDY The application of the flexible Duran mitral annuloplasty ring in the treatment of various mitral valvular diseases is a physiologically appealing method of surgical repair. However, accurate identification of the trigonal structures, which is crucial in selecting the proper ring size, cannot always be made with certainty. A method is proposed to calculate the intertrigonal distance (ITD) from the aortic diameter. METHODS Using digital calipers, the linear intertrigonal distance was measured in human homograft (n = 10) and sheep (n = 10) aortic root specimens. The aortic diameter was obtained from the circumference of the pressurized aortic root. A conversion factor was acquired for each specimen by dividing the aortic diameter with the measured ITD. A single constant conversion factor, which closely approximated the mean of the conversion factors in both groups, was then applied broadly to derive the ITD by calculation from the aortic diameter, which is known. The validity of using this constant conversion factor was tested by comparing the degree of variation of the calculated ITD from the direct measurements of the ITD. RESULTS The mean of the conversion factors was 0.79 and 0.80 in the human and the sheep roots, respectively. The value 0.80 was used as the constant conversion factor in both groups for calculating the ITD. A paired comparison t-test in each group showed the difference between the calculated intertrigonal distance and the direct measurements of the ITD to be insignificant, validating the use of 0.80 as a constant conversion factor. CONCLUSIONS The results of the study suggest that the conversion factor of 0.80 can be reliably used to obtain a calculated value of the intertrigonal distance; this method has the potential to aid the surgeon in determining the intertrigonal distance and the proper ring size.
Collapse
|
79
|
Smulson ME, Pang D, Jung M, Dimtchev A, Chasovskikh S, Spoonde A, Simbulan-Rosenthal C, Rosenthal D, Yakovlev A, Dritschilo A. Irreversible binding of poly(ADP)ribose polymerase cleavage product to DNA ends revealed by atomic force microscopy: possible role in apoptosis. Cancer Res 1998; 58:3495-8. [PMID: 9721847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
During apoptosis, DNA undergoes fragmentation and caspase-3 cleaves poly(ADP-ribose) polymerase (PARP) into both a 24-kDa fragment containing the DNA binding domain and an 89-kDa fragment containing the catalytic and automodification domains. Atomic force microscopy revealed that recombinant full-length PARP bound to plasmid DNA fragments and linked them into chainlike structures. Automodification of PARP in the presence of NAD+ resulted in its dissociation from the DNA fragments, which, nevertheless, remained physically aligned. A recombinant 28-kDa fragment of PARP containing the DNA binding domain but lacking the automodification domain irreversibly bound to and linked DNA fragments in the absence or presence of NAD+. Identical results were obtained on incubation of internucleosomal DNA fragments from apoptotic cells with the products of cleavage of recombinant PARP by purified caspase-3. The 24-kDa product of PARP cleavage by caspase-3 may contribute to the irreversibility of apoptosis by blocking the access of DNA repair enzymes to DNA strand breaks.
Collapse
|
80
|
Pang D, Allman-Farinelli MA, Wong T, Barnes R, Kingham KM. Replacement of linoleic acid with alpha-linolenic acid does not alter blood lipids in normolipidaemic men. Br J Nutr 1998; 80:163-7. [PMID: 9828757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
The effect of partial dietary replacement of linoleic acid (18:2n-6; linoleic acid-rich diet) with alpha-linolenic acid (18:3n-3; alpha-linolenic acid-rich diet) on plasma lipids was investigated in twenty-nine healthy young men. After a 2-week stabilization period subjects were randomly assigned to either the alpha-linolenic acid-rich diet group (n 15), receiving a mean of 10.1 g of alpha-linolenic acid and 12.1 g of linoleic acid/d, or the linoleic acid-rich diet group (n 14), receiving a mean of 1.0 g of alpha-linolenic acid and 21.0 g of linoleic acid/d, for a 6-week test period. Blood samples were taken at the commencement of the stabilization period and at the start (week 0), midpoint (week 3) and endpoint (week 6) of the test period and plasma lipids analysed. The changes occurring on the linoleic acid-rich diet and alpha-linolenic acid-rich diet were compared but no significant differences in the changes in plasma total cholesterol, LDL-cholesterol, HDL-cholesterol, the subfractions HDL2 and HDL3 or triacylglycerols were found. These results indicate that dietary replacement of linoleic acid with alpha-linolenic acid in the diet of healthy male subjects offers similar cardioprotective benefits with respect to lipid metabolism.
Collapse
|
81
|
Eaton RG, Sunde D, Pang D, Singson R. Evaluation of "neocollateral" ligament formation by magnetic resonance imaging after total excision of the proximal interphalangeal collateral ligaments. J Hand Surg Am 1998; 23:322-7. [PMID: 9556276 DOI: 10.1016/s0363-5023(98)80134-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The presence of palpable thickening and maintenance of stability within weeks of total excision of the proximal interphalangeal (PIP) joint collateral ligaments is an established, although somewhat mysterious, phenomenon. To further investigate this postoperative thickening, magnetic resonance imaging (MRI) scans were obtained on 10 joints in 9 patients who had undergone total ligament excision for posttraumatic stiff PIP joints 3 months to 14 years earlier. Although the ultrastructure of these newly formed structures is yet unknown, their palpable consistency, MRI contour, distribution, and signal intensity suggest the formation of a new soft tissue structure, albeit scar, which has all the attributes of a collateral ligament. This MRI of a "neocollateral ligament" would help explain the consistent observation of complete joint stability within weeks following total excision of both PIP joint collateral ligaments. All patients from the 14-year span sampled were found to have a similar, consistent, linear low signal density structure crossing the joint margins and essentially identical to that of a normal collateral ligament.
Collapse
|
82
|
Hodge L, Salome CM, Hughes JM, Liu-Brennan D, Rimmer J, Allman M, Pang D, Armour C, Woolcock AJ. Effect of dietary intake of omega-3 and omega-6 fatty acids on severity of asthma in children. Eur Respir J 1998; 11:361-5. [PMID: 9551739 DOI: 10.1183/09031936.98.11020361] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We assessed the clinical and biochemical effects in asthmatic children of fish oil supplementation and a diet that increases omega-3 and reduces omega-6 fatty acids. Thirty nine asthmatic children aged 8-12 yrs participated in a double-blind, randomized, controlled trial for 6 months during which they received fish oil capsules plus canola oil and margarine (omega-3 group) or safflower oil capsules plus sunflower oil and margarine (omega-6 group). Plasma fatty acids, stimulated tumour necrosis factor alpha (TNFalpha) production, circulating eosinophil numbers and lung function were measured at baseline and after 3 and 6 months of dietary modification. Day and night symptoms, peak flow rates and medication use were recorded for 1 week prior to laboratory visits. Plasma phospholipid omega-3 fatty acids were significantly greater in the omega-3 group at 3 and 6 months compared to the omega-6 group (p<0.001). In the omega-3 group TNFalpha production fell significantly compared with baseline (p=0.026), but the magnitude of change between groups did not reach significance (p=0.075). There were no significant changes in clinical outcome measures. Dietary enrichment of omega-3 fatty acids over 6 months increased plasma levels of these fatty acids, reduced stimulated tumour necrosis factor alpha production, but had no effect on the clinical severity of asthma in these children.
Collapse
|
83
|
Lee ED, Rosenberg CR, Sixsmith DM, Pang D, Abularrage J. Does a physician-patient language difference increase the probability of hospital admission? Acad Emerg Med 1998; 5:86-9. [PMID: 9444351 DOI: 10.1111/j.1553-2712.1998.tb02585.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
|
84
|
Pang D, Vidic B, Rodgers J, Berman BL, Dritschilo A. Atomic force microscope imaging of DNA and DNA repair proteins: applications in radiobiological research. RADIATION ONCOLOGY INVESTIGATIONS 1997; 5:163-9. [PMID: 9327495 DOI: 10.1002/(sici)1520-6823(1997)5:4<163::aid-roi1>3.0.co;2-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
By using the atomic force microscope (AFM), three-dimensional structures of biological specimens may be imaged at nanometer resolution. Furthermore, samples can be imaged in air or in fluid environments. The tapping mode of AFM operation for imaging has offered a significant advance in visualizing soft biological structures, such as DNA, proteins, and membranes. Here, we review the principles underlying the application of this instrument to radiation biological investigations. We focus on examples of proteins involved in the processes of repair of damaged DNA, including poly(ADP-ribose) polymerase, Ku protein, and DNA protein kinase. Novel observations on the character of DNA damage and repair have been addressed by direct visualization of DNA and protein-DNA interactions, such as the observation that the Ku protein is capable of physically joining DNA fragments in vitro. The AFM offers a powerful tool for investigating biologically important molecular interactions that are relevant to DNA damage and repair processes.
Collapse
|
85
|
Chong BW, Babcook CJ, Pang D, Ellis WG. A magnetic resonance template for normal cerebellar development in the human fetus. Neurosurgery 1997; 41:924-8; discussion 928-9. [PMID: 9316055 DOI: 10.1097/00006123-199710000-00029] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
OBJECTIVE Although ultrasound is the primary imaging modality for prenatal anatomic evaluation, some central nervous system malformations may be better defined with high-resolution magnetic resonance imaging (MRI). MRI allows us to visualize the features of brain development that were previously only seen histologically by embryologists and anatomists. Although there are several reports of the postnatal development of the cerebellum as revealed on magnetic resonance (MR) images, systematic MR studies of cerebellar development during the fetal period are lacking. Our objective was to use high-resolution MRI to provide a template of cerebellar development during the late first and early second trimesters, a period when the diagnosis of congenital malformations is most medicoethically relevant. The MR findings were then correlated with histological data. METHODS Twenty-six normal formalin-fixed fetal specimens with a gestational age of 9 to 24 weeks were examined with high-resolution MRI using a conventional clinical magnet and pulse sequences. The MR findings were correlated with the whole-mount histological specimens catalogued in a well-known fetal atlas. RESULTS Resolution of the morphological features of cerebellar development in fetuses greater than 10 weeks gestational age was possible. Development of the rhombic lips, vermis, fourth ventricular roof, foramen of Magendie, and the cerebellar fissures was documented. Development of the cerebellum as revealed on MR images lagged behind the known stages of development by as much as 5 weeks. Features of cerebellar histogenesis were beyond the resolution of MRI. However, differences in signal intensity between gray and white matter of the developing cerebellum were detected and are postulated to represent differences in cellularity and water content of the constituent tissues. CONCLUSION Direct correlation of MR images of fetuses during the late first and early second trimesters with anatomic atlases could result in a mistaken diagnosis of delayed or abnormal development of the posterior fossa contents because of a time lag in the detection of structures on MR images. An MR template of normal cerebellar development would be useful to avoid confusion of normal development with abnormal development and to identify the expected developmental features when provided the estimated gestational age of a fetus.
Collapse
|
86
|
Hu Y, Liu Y, Zhang X, Wang G, Zhou G, Jiang Y, Pang D. [Mutagenicity and carcinogenicity of nabumetone]. HUA XI YI KE DA XUE XUE BAO = JOURNAL OF WEST CHINA UNIVERSITY OF MEDICAL SCIENCES = HUAXI YIKE DAXUE XUEBAO 1997; 28:174-8. [PMID: 10683929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
To study the mutagenicity and carcinogenicity of Nabumetone, we conducted Ames test (TA97, TA98, TA100, TA102), micronucleus test(MN) in mice marrow, chromosomal aberration assay(CA) in CHL cells in vitro, CA in germ cells from testes of mice, and cell transformation test of Syrian hamster embryo(SHE) cells. The maximum concentration was 500 micrograms/plate in Ames test with and without S9 mix. The mice were treated orally(gavage) daily for 4 days in 3 doses in which the maximum dose was 60% LD50 and sampled at the 5th day in MN. The maximum concentration was the dose that the growth of 50% of cells was inhibited in CA of CHL. Cells were harvested after recultured for 18 hours in fresh medium after treatment for 6 hours in the test with S9 mix, and after treatment for 24 or 48 hours in the without S9 mix. The mice were treated orally(gavage) daily for 5 days in 3 doses in which the maximum dose was 1/4 LD50 and sampled at the 6th day in CA of germ cells from testes of mice. 2 micrograms/ml was chosen as the maximum concentration in the cell transformation test of SHE cells, and result was observed after treatment for 9 days, All the tests obtained the same negative result as that reported by other investigators.
Collapse
|
87
|
Pang D, Yoo S, Dynan WS, Jung M, Dritschilo A. Ku proteins join DNA fragments as shown by atomic force microscopy. Cancer Res 1997; 57:1412-5. [PMID: 9108436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The binding of the Ku protein to DNA was investigated using the atomic force microscope. Ku was found to bind predominantly to the ends of double-stranded DNA. Experiments with plasmid DNA revealed that Ku does not bind to circular plasmids but does bind to plasmids that have been linearized by treatment with ionizing radiation. The binding of Ku to poly(dG-dC) x poly(dG-dC) polynucleotides and to a 400-bp DNA EcoRI fragment resulted in a shift in the fragment size distribution to include longer fragments, with internally binding Ku. Furthermore, we observed images consistent with fragments joined together by Ku, showing an interaction with two ends of DNA. These observations suggest that Ku may play a role in physically orienting DNA for ligation by binding the ends of adjacent DNA molecules.
Collapse
|
88
|
Pang D, Burges DC, Sorahan T. Mortality study of nickel platers with special reference to cancers of the stomach and lung, 1945-93. Occup Environ Med 1996; 53:714-7. [PMID: 8943838 PMCID: PMC1128580 DOI: 10.1136/oem.53.10.714] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVES To re-examine mortality patterns in a cohort of nickel platers with no history of chromium plating. METHODS All 284 men first employed by the company in 1945-75 with a minimum employment of three months in the nickel plating department were identified. Workers who had worked in the chromium plating or nickel/chromium plating departments were excluded. Standardised mortality ratios (SMRs), P values, and 95% confidence intervals were calculated. Poisson regression was used to carry out statistical modelling of mortalities within the cohort (internal standard). Four variables were considered to have the potential to influence mortality within the cohort: attained age (age at follow up or age at death), year of starting nickel work, period of follow up (measured from the first period of work with nickel exposure), and duration of exposure to nickel. RESULTS The only significant difference between observed and expected numbers, when investigated by site of cancer and by broad non-cancer groupings, was that for stomach cancer (observed eight, expected 2.49, SMR 322). CONCLUSIONS The study provides only weak evidence that nickel plating is associated with an excess risk of stomach cancer. This cohort of nickel platers does not seem to have experienced any discernible risk of occupational lung cancer. Other studies of nickel platers rather than nickel/chromium platers would be useful.
Collapse
|
89
|
Miller PD, Pollack IF, Pang D, Albright AL. Comparison of simultaneous versus delayed ventriculoperitoneal shunt insertion in children undergoing myelomeningocele repair. J Child Neurol 1996; 11:370-2. [PMID: 8877603 DOI: 10.1177/088307389601100504] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The timing of cerebrospinal fluid shunt insertion for those neonates with hydrocephalus in association with myelomeningocele remains controversial. To examine whether there was a difference in either the complication rate or mean hospital stay for neonates undergoing myelomeningocele repair and shunting under the same anesthetic (simultaneous group) versus those in whom shunt insertion was delayed for several days after myelomeningocele closure (sequential group), we reviewed the results obtained with these two approaches in a series of 69 consecutive patients who underwent both myelomeningocele closure and shunt insertion at our institution between 1987 and 1993. Twenty-one infants underwent simultaneous myelomeningocele repair and shunting, and 48 underwent sequential procedures. The decision to shunt concurrently with myelomeningocele repair rather than in a delayed fashion was based primarily on surgeon preference rather than initial head circumference, which did not differ significantly between the two groups. The frequency and type of hydrocephalus-related complications (e.g., wound leak, cerebrospinal fluid infection, or shunt malfunction) that occurred during the first 6 months after myelomeningocele closure were compared between the two groups. Neither the overall frequency of complications nor the frequency of cerebrospinal fluid infection, shunt malfunction, or symptomatic Chiari malformation differed significantly between the two groups. In contrast, there was a significantly higher rate of myelomeningocele wound leak in the sequential group versus the simultaneous group (eight versus zero; P = .05). Mean hospital stay for the sequential group was also significantly longer than the simultaneous group (22 days versus 13 days; P = .05). These results suggest that simultaneous myelomeningocele repair and ventriculoperitoneal shunt insertion reduces hospital stay and back wound morbidity in those patients with evidence of hydrocephalus at birth, without an inordinate increase in shunt-related complications.
Collapse
|
90
|
Li V, Albright AL, Sclabassi R, Pang D. The role of somatosensory evoked potentials in the evaluation of spinal cord retethering. Pediatr Neurosurg 1996; 24:126-33. [PMID: 8870015 DOI: 10.1159/000121028] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Early detection of clinically significant spinal cord retethering is of paramount importance for the preservation of neurologic function in patients with repaired spinal dysraphic lesions. We retrospectively analyzed 90 children who were followed with serial peroneal somatosensory evoked potentials (SEPs) after a repair of their spinal dysraphic lesions with the objective of evaluating whether SEPs were a useful way of monitoring these children to facilitate early detection of clinically significant retethering. Three hundred and nine studies were performed on these children yielding a mean of 3.4 studies per patient. The median time between SEP studies was 13 months. A clinical examination was performed at the time each SEP was done. Sixty-one patients (68%) had a myelomeningocele; 25 (28%) had a lipomyelomeningocele while other types of dysraphic lesions were found in the remaining 4%. Nineteen patients (21%) had no change in serial SEPs; 7 of these 19 (37%) had a deterioration in clinical status while the SEPs were stable. Twenty-six patients (29%) showed improvement in serial SEPs, however, 3 of the 26 had clinical worsening at the time SEPs improved. SEPs deteriorated in 45 patients (50%); 13 of the 45 had an associated clinical deterioration, and the remaining 32 were stable clinically. Twenty-three patients (26%) had a clinical deterioration; of these only 13 had a corresponding deterioration in SEPs, 7 patients had stable SEPs while 3 had improvement in SEPs at the time of clinical deterioration. This results in a false-positive rate of 71% and a false-negative rate of 43%. We conclude that serial SEPs do not correlate well with clinical status and are not a useful modality for monitoring patients at risk for retethering.
Collapse
|
91
|
Cheong HM, Wickboldt P, Pang D, Chen JH, Paul W. Effects of hydrostatic pressure on the photoluminescence of porous silicon. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 52:11577-11579. [PMID: 9980273 DOI: 10.1103/physrevb.52.r11577] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
92
|
Chen S, Gao Y, Pang D. [National notification of incidence of chronic occupational poisoning during 1984-1993]. ZHONGHUA YU FANG YI XUE ZA ZHI [CHINESE JOURNAL OF PREVENTIVE MEDICINE] 1995; 29:286-9. [PMID: 8556940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Incidence and distribution of chronic occupational poisoning caused by toxic chemicals during 1984 to 1993 throughout the country were summarized and analyzed. Totally, 28,901 cases of chronic occupational poisoning were notified during this period. Lead, benzene and trinitrotoluene were three major toxic chemicals which caused poisoning, with chronic lead poisoning listed the first place, accounting for 47.5% of the total cases. Most of the cases distributed in Laioning, Hunan and Jiangsu Provinces, and 75.4% of the cases occurred in machinery, chemical, metallurgical, non-ferrous, light industries, etc. Incidence of poisoning presented a decreased trend during the past 10 years and the reason of it was described in the paper. The authors indicated that quality assurance in notification of occupational diseases depended on regular implementation of the work in prevention and treatment of occupational diseases.
Collapse
|
93
|
Clark RS, Orr RA, Atkinson CS, Towbin RB, Pang D. Retinal hemorrhages associated with spinal cord arteriovenous malformation. Clin Pediatr (Phila) 1995; 34:281-3. [PMID: 7628174 DOI: 10.1177/000992289503400512] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
|
94
|
Pang D. Surgical complications of open spinal dysraphism. Neurosurg Clin N Am 1995; 6:243-57. [PMID: 7620351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The embryogenesis, closure technique, and preoperative preparation of open myelomeningocele are described in this article. Both early and late complications of myelomeningocele closure are discussed with respect to predisposing factors, diagnosis, treatment, and prevention. These complications include worsened neurological level, wound dehiscence, wound infection, cerebrospinal fluid leak, postoperative ileus, symptomatic Chiari malformation, shunt infection, necrotizing enterocolitis, and problems related to kyphectomy.
Collapse
|
95
|
Dias MS, Pang D. Split cord malformations. Neurosurg Clin N Am 1995; 6:339-58. [PMID: 7620358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Previous classifications of split cord malformations (SCM's), including such terms as diastematomyelia and diplomyelia, have done little to foster a true understanding of these disorders. The authors instead propose a unifying classification in which all SCM's share a common embryogenesis. SCM's are divided into two types, based upon the composition of the dural coverings and intervening mesenchymal tissue. Type I malformations are composed of two dural sacs and a bony or fibrocartilaginous spur; Type II malformations are composed of a single dural sac and intradural fibrous bands. In either case, the intervening mesenchymal elements contribute to progressive neurologic, urologic, and orthopedic deterioration from spinal cord tethering. The natural history of these lesions supports an early and aggressive operative approach to untether the spinal cord before clinical deterioration begins.
Collapse
|
96
|
Allman MA, Pena MM, Pang D. Supplementation with flaxseed oil versus sunflowerseed oil in healthy young men consuming a low fat diet: effects on platelet composition and function. Eur J Clin Nutr 1995; 49:169-78. [PMID: 7774533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
OBJECTIVE To compare the effects of supplementing a low fat diet with an alpha-linolenic acid-rich (C18:3 n-3) oil with a linoleic acid-rich (C18:2 n-6) oil on platelet composition and function. DESIGN Prospective study with random allocation to one of the two oils. SETTING Free-living study. SUBJECTS Eleven healthy young males recruited from within the University. INTERVENTIONS Subjects were allocated to consume 40 g of either flaxseed oil (n = 5) or sunflowerseed oil (n = 6) daily for 23 days. Fasting blood samples were collected at commencement and completion of supplementation for analysis of platelet fatty acids and platelet aggregation. RESULTS The platelet eicosapentaenoic acid (EPA) more than doubled in the group taking flaxseed oil (P < 0.05) but was unchanged in the sunflowerseed group. As a result the platelet EPA:arachidonic acid ratio, considered a marker for thromboxane production and platelet aggregation potential, increased in the flaxseed group (P < 0.05). The aggregation response induced by 0.75 and 2 micrograms of collagen was decreased in those taking flaxseed oil (P < 0.05). CONCLUSION This study provides further evidence that consumption of alpha-linolenic acid-rich oils may offer protective effects against cardiovascular disease over linoleic acid-rich oils via their ability to decrease the tendency of platelets to aggregate.
Collapse
|
97
|
|
98
|
Rutigliano MJ, Pollack IF, Ahdab-Barmada M, Pang D, Albright AL. Intracranial infantile myofibromatosis. J Neurosurg 1994; 81:539-43. [PMID: 7931587 DOI: 10.3171/jns.1994.81.4.0539] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Infantile myofibromatosis is a proliferative disorder of infancy and early childhood characterized by nodular or diffuse growth of lesions that are comprised of a mixture of mesenchymal elements within the skin, subcutaneous tissues, skeletal muscle, bone, and/or visceral organs. Although these pseudotumors are considered to be the most common fibrous "neoplasm" of infancy, central nervous system involvement is reportedly rare. During the last 7 years, the authors have treated three children with intracranial myofibromas who presented at 6 weeks, 7 months, and 3 3/4 years of age, respectively. Each child had a large calvarial mass that produced significant brain compression despite a paucity of neurological signs. On computerized tomography, these tumors were isodense to brain tissue, enhanced strongly with intravenous contrast material, and showed smoothly marginated bone erosion without surrounding sclerosis. On magnetic resonance imaging, the tumors were hypointense on T1-weighted images, with dense enhancement following the administration of intravenous contrast medium, and hyperintense on T2-weighted images. At operation, the tumors were highly vascular and appeared to arise from within the leaves of the dura, eroding through the overlying bone, but not violating the galeal or arachnoidal layers. Two of the lesions were adherent to major dural venous sinuses. Both of these lesions were completely resected in continuity with the involved dura, and have not recurred 6 years and 1 year, respectively, postoperatively. However, in one patient in whom the involved dura was not resected at the initial procedure, the tumor recurred rapidly. A complete excision of the tumor and involved dura was then performed and the patient is now recurrence-free, 5 1/2 years after the second surgical resection. All patients tolerated resection well, but two have required cranioplasty for persistent calvarial defects. The surgical experience with these lesions is reviewed and the distinctive features of their clinical presentation, radiographic appearance, operative management, and outcome are discussed.
Collapse
|
99
|
Pang D, Altschuler E. Low-pressure hydrocephalic state and viscoelastic alterations in the brain. Neurosurgery 1994; 35:643-55; discussion 655-6. [PMID: 7808607 DOI: 10.1227/00006123-199410000-00010] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Most shunt-dependent hydrocephalic patients present with predictable symptoms of headache and mental status changes when their cerebrospinal fluid shunts malfunction. Their intracranial pressure (ICP) is usually high, and they usually respond to routine shunt revision. This report describes 12 shunted patients who were admitted with the full-blown hydrocephalic syndrome but with low to low-normal ICP. All 12 patients had been maintained previously on medium-pressure shunts. Their symptoms included headache, lethargy, obtundation, and cranial neuropathies. At peak symptoms, their ventricular sizes were large (ventricular/biparietal ratio of 0.35 to 0.45) in six and massive (ventricular/biparietal ratio > 0.45) in six and their ICPs ranged from 2.2 to 6.6 mm Hg, with a mean of 4.4 +/- 1.3 mm Hg (+/- standard deviation), i.e., below or well within the pressure range of their shunts. The pressure volume index of three patients at peak symptoms ranged from 39.2 to 48.5 ml, with a mean of 43.9 +/- 4.6 ml, which represents a 190% increase from the predicted normal value. Seven patients failed to improve with multiple shunt revisions, including the use of low-pressure valves. In 11 patients, symptoms and ventriculomegaly were not reversed except with prolonged external ventricular drainage at subzero pressures (mean external ventricular drainage nadir pressure of -5.7 +/- 3.6 mm Hg, for a mean period of 22.2 days). During external ventricular drainage treatment, symptoms correlated only with ventricular size and not with ICP. All 11 were subsequently treated successfully with a new medium- or low-pressure shunt. One patient was treated successfully with prolonged shunt pumping. We postulate that: 1) the development of this low-pressure hydrocephalic state is related to alteration of the viscoelastic modulus of the brain, secondary to expulsion of extracellular water from the brain parenchyma, and to structural changes in brain tissues due to prolonged overstretching; 2) certain patients are susceptible to developing low-pressure hydrocephalic state because of an innate low brain elasticity due to bioatrophic changes; 3) low-pressure hydrocephalic state symptoms are due not to pressure changes but to brain tissue distortion and cortical ischemia secondary to severe ventricular distortion and elevated radial compressive stresses within the brain; and 4) treatment must be directed toward allowing the entry of water into the brain parenchyma and the restoration of baseline brain viscoelasticity.
Collapse
|
100
|
Grabb PA, Pang D. Magnetic resonance imaging in the evaluation of spinal cord injury without radiographic abnormality in children. Neurosurgery 1994; 35:406-14; discussion 414. [PMID: 7800131 DOI: 10.1227/00006123-199409000-00007] [Citation(s) in RCA: 129] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Seven children aged birth to 17 years with spinal cord injury without radiographic abnormality (SCIWORA) were studied with magnetic resonance imaging (MRI) between 3 hours and 16 days after the injury. There were six cervical cord injuries and one thoracic cord injury. The MRI findings were divided into two groups: extraneural and neural. The extraneural findings included one case of anterior longitudinal ligament disruption and anterior C6-C7 disc herniation associated with hyperextension; one case of posterior longitudinal ligament disruption and C2-C3 disc herniation associated with lateral flexion; and one case of C6-C7 disc abnormality consistent with increased water content occurring with hyperflexion. These ligament and disc injuries did not correlate with late instability. The neural MRI findings included one case of cord transection with rostral cord stump hemorrhage and one case of hemorrhage involving the majority of the cord's transverse diameter, both associated with permanent complete cord injuries; one case of hemorrhage involving a minor portion of the cord and of the brain stem's transverse diameter associated with a severe partial cord injury but subsequent incomplete improvement; one case of edema without hemorrhage associated with Brown-Séquard syndrome and subsequent incomplete improvement; and three cases of normal cord signal and outline. Two of the latter patients had mild cord injuries that recovered completely. In the third, a child with complete T12 sensorimotor paralysis at presentation, the normal MRI findings predicted the subsequent complete recovery. No extraaxial compressive lesion was demonstrated in these seven children.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
|