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Roberts-Thomson KF, Spencer AJ, Do LG, Szuster FS, Hai TD, Nguyen TT. The Second National Oral Health Survey of Vietnam, 1999: background and methodology. THE NEW ZEALAND DENTAL JOURNAL 2010; 106:61-66. [PMID: 20608310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
UNLABELLED Few high-quality epidemiological surveys of oral health have been conducted in developing countries. A National Oral Health Survey of Vietnam was previously conducted in 1989. OBJECTIVE To conduct a Second National Oral Health Survey to facilitate planning of preventive and treatment programmes and the dental workforce in Vietnam. DESIGN The 1999 survey utilised a multistage stratified random sampling strategy to obtain a random sample of the Vietnamese population. The population was stratified by province, urban/rural location and age in order to ensure adequate representation. Participants were clustered into schools (children) or communes (adults). Data were collected through a social survey, and dental examinations were conducted by calibrated examiners. RESULTS High percentages of the target samples in each stratum were obtained. Inter-examiner and intra-examiner reliability were good to high (kappa: 0.48-0.98). All data were weighted to adjust for the probabilities of selection and known biases to provide unbiased estimates at provincial and national level. CONCLUSION The National Oral Health Survey of Vietnam was a high-quality epidemiological survey with high participation rates. This was made possible through strong support from the Vietnamese Ministry of Health and regional and local officials.
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Michiels W, Gache P, Danis D, Favre N, Fehlmann-Rielle L, Moreno V, Nguyen TT, Perez B, Rege-Colet N. [Preventing recurrence of conduct in a state of alcoholic intoxication: before]. REVUE MEDICALE SUISSE 2010; 6:637-639. [PMID: 20408368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
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Schimmelmann BG, Friedel S, Nguyen TT, Sauer S, Ganz Vogel CI, Konrad K, Wilhelm C, Sinzig J, Renner TJ, Romanos M, Palmason H, Dempfle A, Walitza S, Freitag C, Meyer J, Linder M, Schäfer H, Warnke A, Lesch KP, Herpertz-Dahlman B, Hinney A, Hebebrand J. Exploring the genetic link between RLS and ADHD. J Psychiatr Res 2009; 43:941-5. [PMID: 19223043 DOI: 10.1016/j.jpsychires.2009.01.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2008] [Revised: 01/13/2009] [Accepted: 01/13/2009] [Indexed: 01/27/2023]
Abstract
Attention deficit/hyperactivity disorder (ADHD) is a highly heritable neurodevelopmental disorder of childhood onset. Clinical and biological evidence points to shared common central nervous system (CNS) pathology of ADHD and restless legs syndrome (RLS). It was hypothesized that variants previously found to be associated with RLS in two large genome-wide association studies (GWA), will also be associated with ADHD. SNPs located in MEIS1 (rs2300478), BTBD9 (rs9296249, rs3923809, rs6923737), and MAP2K5 (rs12593813, rs4489954) as well as three SNPs tagging the identified haplotype in MEIS1 (rs6710341, rs12469063, rs4544423) were genotyped in a well characterized German sample of 224 families comprising one or more affected sibs (386 children) and both parents. We found no evidence for preferential transmission of the hypothesized variants to ADHD. Subsequent analyses elicited nominal significant association with haplotypes consisting of the three SNPs in BTBD9 (chi2 = 14.8, df = 7, nominal p = 0.039). According to exploratory post hoc analyses, the major contribution to this finding came from the A-A-A-haplotype with a haplotype-wise nominal p-value of 0.009. However, this result did not withstand correction for multiple testing. In view of our results, RLS risk alleles may have a lower effect on ADHD than on RLS or may not be involved in ADHD. The negative findings may additionally result from genetic heterogeneity of ADHD, i.e. risk alleles for RLS may only be relevant for certain subtypes of ADHD. Genes relevant to RLS remain interesting candidates for ADHD; particularly BTBD9 needs further study, as it has been related to iron storage, a potential pathophysiological link between RLS and certain subtypes of ADHD.
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Genini S, Nguyen TT, Bürgi E, Stranzinger G, Vögeli P, Giuffra E. Elimination of INPP4A and SLC5A7 as candidate genes for congenital progressive ataxia and spastic paresis in pigs. Anim Genet 2009; 40:789-90. [PMID: 19397514 DOI: 10.1111/j.1365-2052.2009.01889.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Dhond MR, Whitley TB, Singh S, Nguyen TT, Bommer WJ. Incidence and significance of profound hypotension during dobutamine stress echocardiography. Clin Cardiol 2009; 23:47-50. [PMID: 10680029 PMCID: PMC6654861 DOI: 10.1002/clc.4960230109] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND Mild hypotension (drops of systolic blood pressure of > or = 20 mmHg) occurs in 14-38% of dobutamine stress echo (DSE) and carries a good prognosis for subsequent cardiac events. The incidence and significance of more profound hypotension (PH) (> or = 50 mmHg) is unknown. HYPOTHESIS The aim of the study was to determine the incidence of PH during DSE and its prognosis for subsequent cardiac events. METHODS We reviewed 617 DSE performed at our institution between 1992 and 1996 and identified two DSE subgroups. The first group (PH group) consisted of all patients with PH during DSE. A second group was selected with baseline characteristics similar to the PH group but without PH during DSE (non-PH group). Follow-up was by a physician chart review and direct telephone contact. Cardiac event rates were determined for hard [myocardial infarction (MI), or cardiac death] and soft (angina, congestive heart failure, coronary angioplasty, or coronary bypass surgery) events occurring after the DSE. RESULTS Of the 617 DSE performed, 16 (3%) patients developed PH (PH group) during DSE, with 13 showing no inducible ischemia. The hard and soft cardiac event rate in this 13 PH group was 46% (mean follow-up of 28.7 +/- 18 months). Of the non-PH group, 32 patients had a negative DSE with a coronary event rate of 12.5%. Profound hypotension correlated with a significantly higher cardiac event rate (p < 0.02). CONCLUSIONS The incidence of PH during DSE is low (3%) and appears to predict a worse prognosis for subsequent cardiac events.
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Islam FMA, Nguyen TT, Wang JJ, Tai ES, Shankar A, Saw SM, Aung T, Lim SC, Mitchell P, Wong TY. Quantitative retinal vascular calibre changes in diabetes and retinopathy: the Singapore Malay eye study. Eye (Lond) 2008; 23:1719-24. [DOI: 10.1038/eye.2008.362] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Roth CL, Hinney A, Reinehr T, Schreiner F, Nguyen TT, Müller T, Scholl C, Woelfle J, Karpushova A, Schäfer H, Nöthen MM, Hebebrand J. TCF7L2 polymorphism rs7903146 and predisposition for type 2 diabetes mellitus in obese children. Horm Metab Res 2008; 40:713-7. [PMID: 18546086 DOI: 10.1055/s-2008-1078720] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Polymorphism RS7903146 in transcription factor 7-like2 gene ( TCF7L2) is associated with type 2-diabetes mellitus (T2DM) in adults. Concerned with predisposition for diabetes mellitus in obese children, we tested if risk genotypes TC and TT of rs7903146 are more common in obese children with increased homeostasis model assessment insulin resistance index (HOMA-IR) compared to obese controls with normal HOMA-IR. As exploratory analysis, we also calculated beta-cell function for these risk genotypes and measured glucagon-like peptide 1 (GLP-1) in a subgroup. The cohort was 401 obese children (BMI > 2SDS; 211 female; 59% presenting increased HOMA-IR) from two German outpatient obesity referral centers. Genotype distributions in patients presenting increased HOMA-IR (TT: 10.18%, CT: 35.65%, CC: 54.17%) and in patients with normal HOMA-IR (TT: 8.66%, CT: 42.67%, CC: 48.67%) provided no significant effect of these two risk genotypes (p > 0.2). Correction for possible confounder's gender, age, pubertal stage, and BMI revealed no association with glucose metabolism parameters including GLP-1. However, exploratory HOMA-B% index was comparatively higher in TT-homozygotes (p=0.021) as compared to CC-homozygotes. We conclude that even though TT and CT genotypes were not higher in patients presenting elevated HOMA-IR, the higher HOMA-B% index in TT-homozygotes indicates TCF7L2 to be a susceptibility gene for the development of impaired glucose tolerance in obese children as demonstrated in several adult cohort studies.
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Jones MV, Nguyen TT, Deboy CA, Griffin JW, Whartenby KA, Kerr DA, Calabresi PA. Behavioral and pathological outcomes in MOG 35-55 experimental autoimmune encephalomyelitis. J Neuroimmunol 2008; 199:83-93. [PMID: 18582952 DOI: 10.1016/j.jneuroim.2008.05.013] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2008] [Revised: 05/15/2008] [Accepted: 05/15/2008] [Indexed: 01/17/2023]
Abstract
We measured inflammatory and neural markers of disease from 7 days to one year after induction of experimental autoimmune encephalomyelitis (EAE) by immunization with myelin oligodendrocyte glycoprotein (MOG) peptide. Axon loss began before behavioral signs when T cell infiltration and microglial activation were very subtle. Remyelination was only detectable ultrastructurally. Axon numbers in the dorsal column plateau around day 30 p.i. while behavioral measures (EAE scores, rotarod, grip strength) partially recover. These results provide a starting point for testing potential neuroprotective treatments for multiple sclerosis (MS).
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Romanos M, Freitag C, Jacob C, Craig DW, Dempfle A, Nguyen TT, Halperin R, Walitza S, Renner TJ, Seitz C, Romanos J, Palmason H, Reif A, Heine M, Windemuth-Kieselbach C, Vogler C, Sigmund J, Warnke A, Schäfer H, Meyer J, Stephan DA, Lesch KP. Genome-wide linkage analysis of ADHD using high-density SNP arrays: novel loci at 5q13.1 and 14q12. Mol Psychiatry 2008; 13:522-30. [PMID: 18301393 DOI: 10.1038/mp.2008.12] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Previous genome-wide linkage studies applied the affected sib-pair design; one investigated extended pedigrees of a genetic isolate. Here, results of a genome-wide high-density linkage scan of attention-deficit/hyperactivity disorder (ADHD) using an array-based genotyping of approximately 50 K single nucleotide polymorphism (SNPs) markers are presented. We investigated eight extended pedigrees of German origin that were non-related, not part of a genetic isolate and ascertained on the basis of clinical referral. Two parametric analyses maximizing LOD scores (MOD) and a non-parametric analysis for both a broad and a narrow phenotype approach were conducted. Novel linkage loci across all families were detected at 2q35, 5q13.1, 6q22-23 and 14q12, within individual families at 18q11.2-12.3. Further linkage regions at 7q21.11, 9q22 and 16q24.1 in all families, and at 1q25.1, 1q25.3, 9q31.1-33.1, 9q33, 12p13.33, 15q11.2-13.3 and 16p12.3-12.2 in individual families replicate previous findings. High-resolution linkage mapping points to several novel candidate genes characterized by dense expression in the brain and potential impact on disorder-relevant synaptic transmission. Our study provides further evidence for common gene effects throughout different populations despite the complex multifactorial etiology of ADHD.
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Angelescu DG, Linse P, Nguyen TT, Bruinsma RF. Structural transitions of encapsidated polyelectrolytes. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2008; 25:323-334. [PMID: 18385931 DOI: 10.1140/epje/i2007-10301-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2007] [Accepted: 02/18/2008] [Indexed: 05/26/2023]
Abstract
Conformations and structural transitions of polyelectrolytes strictly confined onto a spherical 2D surface have been investigated by scaling descriptions based on physical arguments concerning polyelectrolyte adsorption onto planar surface and liquid crystals as well as by Monte Carlo simulations using a bead-spring model with short-range and electrostatic repulsions. In case of the electrostatic screened regime, a disordered-ordered (spiral) transition at increasing persistence length of the chain was found. It was predicted that the transition occurred when the persistence length is comparable with the mean spacing between adjacent strands of the ordered chain. The presence of a non-screened electrostatic repulsion led to a more complex behavior with i) a re-entrant order-disorder transition and ii) a tennis ball texture as an additional smectic/nematic structure. The various competing structures given by the theory were recovered by the Monte Carlo simulations, which also indicated that the tennis ball texture was favored over the spiral structure by the long-range interactions for semi-flexible chains.
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Nguyen TT, Wright JD, Powell MA, Gibb RK, Rader JS, Allsworth JE, Mutch DG. Prognostic factors associated with response in platinum retreatment of platinum-resistant ovarian cancer. Int J Gynecol Cancer 2008; 18:1194-9. [PMID: 18217964 DOI: 10.1111/j.1525-1438.2007.01184.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The goal of this study was to determine the factors associated with response to platinum retreatment in patients with platinum-resistant ovarian cancer. A review of patients with epithelial ovarian cancer retreated with cisplatin or carboplatin between 2002 and 2004 was performed. The platinum-free interval (PFI) and treatment-free interval (TFI) were determined for each patient. Response was based on serial CA125 levels using a modification of the Rustin criteria. Patients with clinical benefit ([CB] those who attained at least stable disease) were compared to patients with disease progression (PD). An analysis was performed to determine factors associated with CB in platinum-resistant patients retreated with platinum. Of 48 patients identified, 37 were evaluable included in this analysis. CB was observed in 27 (73%) while disease progression was noted in 10 (27%) women. The PFI was longer in those women who achieved CB (12.3 vs 6.9 months; P = 0.02). The TFI was 7.1 months for patients benefited from platinum retreatment vs 3.5 months for those with disease progression (P = 0.06). There was no statistically significant difference in the number of cytotoxic agents between the time of platinum retreatment and the prior platinum regimen (2 vs 1.5 months; P = 0.61). A prolonged PFI was associated with an improved chance of achieving CB with platinum retreatment. There was no association between the response to platinum retreatment and the number of intervening cytotoxic agents utilized. Further prospective study is warranted to define the optimal timing of platinum retreatment.
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Wang HJ, Wermter AK, Nguyen TT, Scherag A, Reichwald K, Waldenmaier B, Lichtner P, Bettecken T, Hebebrand J, Hinney A. No association of sequence variants in the neuropeptide Y2 receptor (NPY2R) gene with early onset obesity in Germans. Horm Metab Res 2007; 39:840-4. [PMID: 17992642 DOI: 10.1055/s-2007-992127] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The neuropeptide Y2 receptor (NPY2R) has been implicated in body weight regulation both in humans and rodents. We investigated if genetic variation in the NPY2R gene is associated with obesity in German extremely obese children and adolescents. The coding sequence and predicted promoter of the NPY2R were screened for variations. Subsequently, case-control (184 extremely obese children and adolescents: mean body mass index [BMI] 35.7+/-6.1 kg/m(2), 277 lean students: mean BMI 18.2+/-1.1 kg/m(2)) and family-based (770 parental pairs with a total of 1081 obese off-spring) association analyses were conducted in independent samples. We identified 14 sequence variants (seven novel variants including two coding variants c.369C >T and c.834G >A), five of which were detected once, each in the heterozygous state. In case-control analyses we did not detect association with obesity for seven common (minor allele frequency >1%) variants (all p >0.16); additional gender-stratified analyses employing several genetic models and haplotype analyses were also nonsignificant. Furthermore, in a family-based association study for coding synonymous SNP rs1047214 (Ile195) we found no evidence for a transmission disequilibrium in the total or in the gender-stratified PDT analyses (all p >0.50). In conclusion, we did not find evidence for an involvement of genetic variation in the NPY2R in early onset obesity in German samples.
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Genini S, Nguyen TT, Malek M, Talbot R, Gebert S, Rohrer G, Nonneman D, Stranzinger G, Vögeli P. Radiation hybrid mapping of 18 positional and physiological candidate genes for arthrogryposis multiplex congenita on porcine chromosome 5. Anim Genet 2006; 37:239-44. [PMID: 16734683 DOI: 10.1111/j.1365-2052.2006.01447.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report the chromosomal assignment of 18 porcine genes to human homologues using the INRA-Minnesota swine radiation hybrid panel (IMpRH). These genes (CACNA1C, COL2A1, CPNE8, C3F, C12ORF4, DDX11, GDF11, HOXC8, KCNA1, MDS028, TMEM106C, NR4A1, PHB2, PRICKLE1, Q6ZUQ4, SCN8A, TUBA8 and USP18) are located on porcine chromosome 5 (SSC5) and represent positional and functional candidates for arthrogryposis multiplex congenita (AMC), which maps to SSC5. CPNE8, PRICKLE1, Q6ZUQ4 and TUBA8 were mapped to the interval for pig AMC between microsatellites SW152 and SW904. Three SNPs in TUBA8 co-segregated with the AMC phenotype in 230 pigs of our research population without recombination and could be used as a genetic marker test for AMC. In addition, we provide evidence that a small chromosomal region of HSA22q11.2 evolutionarily corresponds to SSC5q12-q22 (and contains the human homologues of porcine SW152, Q6ZUQ4, TUBA8 and USP18), while the regions flanking HSA22q11.2 on SSC5 correspond to HSA12p13 and HSA12q12. We identified seven distinct chromosomal blocks, further supporting extensive rearrangements between genes on HSA12 and HSA22 in the AMC region on SSC5.
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Nguyen TT, Bruinsma RF, Gelbart WM. Continuum theory of retroviral capsids. PHYSICAL REVIEW LETTERS 2006; 96:078102. [PMID: 16606144 DOI: 10.1103/physrevlett.96.078102] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2005] [Indexed: 05/08/2023]
Abstract
We present a self-assembly phase diagram for the shape of retroviral capsids, based on continuum elasticity theory. The spontaneous curvature of the capsid proteins drives a weakly first-order transition from spherical to spherocylindrical shapes. The conical capsid shape which characterizes the HIV-1 retrovirus is never stable under unconstrained energy minimization. Only under conditions of fixed volume and/or fixed spanning length can the conical shape be a minimum energy structure. Our results indicate that, unlike the capsids of small viruses, retrovirus capsids are not uniquely determined by the molecular structure of the constituent proteins but depend in an essential way on physical constraints present during assembly.
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Craig W, Gargano D, Scotti N, Nguyen TT, Lao NT, Kavanagh TA, Dix PJ, Cardi T. Direct gene transfer in potato: a comparison of particle bombardment of leaf explants and PEG-mediated transformation of protoplasts. PLANT CELL REPORTS 2005; 24:603-11. [PMID: 16160836 DOI: 10.1007/s00299-005-0018-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2005] [Revised: 04/26/2005] [Accepted: 05/15/2005] [Indexed: 05/04/2023]
Abstract
Direct gene transfer methods in potato would facilitate the transfer of multiple genes and the manipulation of metabolic pathways in this species. In this study, up to 1.8 transformation events per shot (=0.5 per bombarded leaf) and 67.2 events per million protoplasts treated were obtained with particle bombardment and PEG-mediated direct DNA uptake, respectively. Limited disassociation of both HPT and GUS genes appeared to occur during the process of integration in only 19% of transformants. A large number of transformed potato plants with transgene expression at levels comparable to Agrobacterium-mediated transformation was obtained. High levels of GUS expression were only obtained in lines derived from PEG treatment. No correlation between the number of gene insertions and gene expression levels was found, suggesting that multiple insertions may have little or no effect on transgene expression.
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91
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Nguyen TT, Gopal A, Lee KYC, Witten TA. Surface charge relaxation and the pearling instability of charged surfactant tubes. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2005; 72:051930. [PMID: 16383668 DOI: 10.1103/physreve.72.051930] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2004] [Revised: 07/28/2005] [Indexed: 05/05/2023]
Abstract
The pearling instability of bilayer surfactant tubes was recently observed during the collapse of fluid monolayers of binary mixtures of Dimyristoylphosphocholine (DMPC): Palmitoyloleoylphosphoglycerol (POPG) and Dipalmitoylphosphocholine (DPPC):POPG surfactants. It can be explained by a Rayleigh-like instability under the action of the bilayer surface tension. The magnitude of surface tension is dictated by the electrostatic interaction between charged surfactants. Relaxation of charged molecules is proposed here as an additional mechanism driving the instability. We find the functional dependence of the electrostatic surface tension and relaxation energies on the screening length kappa(-1) explicitly. Relaxation lowers the cost of bending a tube into pearls making the cylindrical tube even more unstable. It is known that for the weak screening case in which the tube radius is smaller than the screening length of the solution, this effect is important. However, for the case of strong screening it is negligible. For the experiments mentioned, the situation is marginal. In this case, we show that the effect of relaxation remains small. It contributes about 20% to the total electrostatic energy.
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Nguyen TT, Bruinsma RF, Gelbart WM. Elasticity theory and shape transitions of viral shells. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2005; 72:051923. [PMID: 16383661 DOI: 10.1103/physreve.72.051923] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2005] [Indexed: 05/05/2023]
Abstract
Recently, continuum elasticity theory has been applied to explain the shape transition of icosahedral viral capsids--single-protein-thick crystalline shells--from spherical to "buckled" or faceted as their radius increases through a critical value determined by the competition between stretching and bending energies of a closed two-dimensional (2D) elastic network. In the present work we generalize this approach to capsids with nonicosahedral symmetries, e.g., spherocylindrical and conical shells. One key additional physical ingredient is the role played by nonzero spontaneous curvature. Another is associated with the special way in which the energy of the 12 topologically required fivefold sites depends on the "background" local curvature of the shell in which they are embedded. Systematic evaluation of these contributions leads to a shape "phase" diagram in which transitions are observed from icosahedral to spherocylindrical capsids as a function of the ratio of stretching to bending energies and of the spontaneous curvature of the 2D protein network. We find that the transition from icosahedral to spherocylindrical symmetry is continuous or weakly first order near the onset of buckling, leading to extensive shape degeneracy. These results are discussed in the context of experimentally observed variations in the shapes of a variety of viral capsids.
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Nguyen NT, Gelfand D, Chang K, Varela JE, Nguyen TT, Hayashi M, Wilson SE, Luketich JD. Laparoscopic esophagectomy. MINERVA CHIR 2005; 60:327-38. [PMID: 16210983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Minimally invasive esophagectomy is emerging as an alternative option to open esophagectomy for benign and malignant esophageal diseases. This article provides a detailed review of the history of minimally invasive esophagectomy and an update on the currently accepted techniques for minimally invasive esophagectomy and its outcomes.
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Nguyen TT, Genini S, Ménétrey F, Malek M, Vögeli P, Goe MR, Stranzinger G. Application of bovine microsatellite markers for genetic diversity analysis of Swiss yak (Poephagus grunniens). Anim Genet 2005; 36:484-9. [PMID: 16293121 DOI: 10.1111/j.1365-2052.2005.01357.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
In order to assess the applicability of bovine microsatellite markers for population genetic studies in Swiss yak, 131 bovine microsatellite markers were tested on a panel of 10 animals. Efficient amplification was observed for 124 markers (94.6%) with a total of 476 alleles, of which 117 markers (94.3%) were polymorphic. The number of alleles per locus among the polymorphic markers ranged from two to nine. Seven loci (ILSTS005, BMS424B, BMS1825, BMS672, BM1314, ETH123 and BM6017) failed to amplify yak genomic DNA. Two cattle Y-chromosome specific microsatellite markers (INRA126 and BM861) amplified genomic DNA from both male and female yaks. However, two additional markers on cattle Y-chromosome (INRA124 and INRA189) amplified DNA from only males. Of the polymorphic markers, 24 microsatellites proposed by CaDBase for within- and cross-species comparisons and two additional highly polymorphic markers (MHCII and TGLA73) were used to investigate the genetic variability and the population structure of a Swiss yak herd that included 51 additional animals. The polymorphic information content ranged from 0.355 to 0.752, while observed heterozygosity (HO) ranged from 0.348 to 0.823. Furthermore, a set of 13 markers, organized into three multiplex polymerase chain reactions, was evaluated for routine parentage testing. This set provided an exclusion probability in a family of four yaks (both parents and two offspring) of 0.995. These microsatellites serve as useful tools for genetic characterization of the yak, which continues to be an important domestic livestock species.
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Nguyen TT, Nguyen BX, Stranzinger G. Characterization of G-banded chromosomes of a female saola (Pseudoryx nghetinhensis,2n = 50) and X chromosome i dentification by means of fluorescent in situ hybridization. Cytogenet Genome Res 2005; 109:502-6. [PMID: 15905645 DOI: 10.1159/000084210] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2004] [Accepted: 09/27/2004] [Indexed: 11/19/2022] Open
Abstract
The saola (Pseudoryx nghetinhensis) is a newly discovered large mammal species, belongs to the subfamily Bovinae and is listed as being endangered. Due to the limitation of the material available, no cytogenetic studies have been carried out on this species. In the present study, preliminary cytogenetic analysis was undertaken on cultured female fibroblast cells to characterize the karyotype organization of saola. An examination of 120 Giemsa stained metaphases showed the diploid chromosome number of 2n = 50, including five bi-armed chromosome pairs. The distribution of constitutive heterochromatin in saola was studied. However, the variability in the size of C-bands was not significant on all the homologous chromosomes. The X chromosome pair, corresponding to the largest telocentric chromosomes, was identified by fluorescent in situ hybridization (FISH) using a bacterial artificial chromosome clone (BAC 0577G05, which maps to BTAXq25-->q33). In comparison to the standard karyotype of cattle (ISCNDB 2000), a G-banded ideogram of saola (about 390 band level) was presented. This work, therefore, provided a basic insight into the karyotype organization of this endangered species and will be particularly useful to improve the understanding of differences of genomes between related species.
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Nguyen TT, Ménétrey F, Genini S, Nguyen VL, Vögeli P, Nguyen BX, Stranzinger G. Application of bovine microsatellite markers on Saola (Pseudoryx nghetinhensis). J Anim Breed Genet 2005; 122:195-8. [PMID: 16130471 DOI: 10.1111/j.1439-0388.2005.00511.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The aim of the present study was to assess the applicability of bovine microsatellite markers on Saola (Pseudoryx nghetinhensis). A total of 127 microsatellite markers were tested on a male and a young female Saola. An efficient amplification was observed for 123 markers (96.8%), 73 markers (59.3%) were polymorphic. Four loci (BM2304, BMS1928, BMS779 and ILSTS006) on cattle chromosomes 1, 4, 7 and 8, respectively, failed to amplify in Saola. Two cattle Y-chromosome-specific microsatellite markers (INRA126 and BM861) were successfully amplified from both sexes in Saola. However, two additional markers (INRA124 and INRA189) on Y-chromosome failed to amplify in the female animal. These results show that most of the bovine microsatellite markers are applicable in Saola and therefore they can be used to study the phylogenetic relationships and the genetic diversity of the Saola population.
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97
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Nguyen TT, Maartens NF. Images in neuroscience: urge incontinence and an abnormal patch of skin. J Clin Neurosci 2005; 12:271-2, 295. [PMID: 15851080 DOI: 10.1016/j.jocn.2004.06.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2004] [Accepted: 06/28/2004] [Indexed: 11/24/2022]
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98
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Quyen DT, Nguyen TT, Le TTG, Kim HK, Oh TK, Lee JK. A novel lipase/chaperone pair from Ralstonia sp. M1: analysis of the folding interaction and evidence for gene loss in R. solanacearum. Mol Genet Genomics 2004; 272:538-49. [PMID: 15668771 DOI: 10.1007/s00438-004-1084-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2004] [Accepted: 10/14/2004] [Indexed: 11/30/2022]
Abstract
A microbial strain (referred to as M1) that produces an extracellular lipase was isolated from a soil sample in Vietnam, and identified as a Ralstonia species by partial sequencing of its 16S rDNA. A genomic library was constructed from Pst I fragments, and a colony showing lipase activity was selected for further analysis. Sequencing of the 4.7-kb insert in this clone (named M1-72) revealed one incomplete and three complete ORFs, predicted to encode a partial hypothetical glutaminyl tRNA synthetase (304 aa), a hypothetical transmembrane protein (500 aa), a lipase (328 aa) and a lipase chaperone (352 aa), respectively. Alignment of the insert sequence with the corresponding region of the genome of R. solanacearum GMI1000 (GenBank Accession No. AL646081) confirmed the presence in the latter of the genes for the hypothetical transmembrane protein and glutaminyl tRNA synthetase, which exhibited 89-91% identity to their counterparts in M1. However, R. solanacearum GMI1000 lacks the complete lipase-encoding gene and the major part of the chaperone-encoding gene, creating a so-called "black hole". The deduced amino acid sequences of the products of the lipase gene lipA and chaperone gene lipB from strain M1 shared 49.3-60.3% and 23.9-32.7% identity, respectively, with those of the Burkholderia lipase/chaperone subfamily I.2. lipB is located downstream of lipA, and separated from it by only 9 bp, and each gene has a putative ribosome binding site. The mature lipase LipA, a His-tagged derivative (LipAhis), the tagged full-length chaperone LipBhis and a truncated form (DeltaLipBhis) lacking the 56 N-terminal residues were expressed in Escherichia coli BL21. LipA, LipAhis and DeltaLipBhis could be expressed at high levels (70, 15 and 12 mg/g wet cells, respectively) and were easily purified. However, LipBhis was expressed at a much lower level which precluded purification. The specific activity of purified LipAhis, expressed on its own, was very low (<52 U/mg). However, after co-incubation with the purified DeltaLipBhis in vitro, the specific activity of the enzyme was markedly enhanced, indicating that the chaperone facilitated correct folding of the enzyme. A lipase:chaperone ratio of 1:10 was found to be optimal, yielding an enzyme preparation with a specific activity of 650 U/mg.
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Nguyen TT, Biadillah Y, Mongrain R, Brunette J, Tardif JC, Bertrand OF. A Method for Matching the Refractive Index and Kinematic Viscosity of a Blood Analog for Flow Visualization in Hydraulic Cardiovascular Models. J Biomech Eng 2004; 126:529-35. [PMID: 15543873 DOI: 10.1115/1.1785812] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In this work, we propose a simple method to simultaneously match the refractive index and kinematic viscosity of a circulating blood analog in hydraulic models for optical flow measurement techniques (PIV, PMFV, LDA, and LIF). The method is based on the determination of the volumetric proportions and temperature at which two transparent miscible liquids should be mixed to reproduce the targeted fluid characteristics. The temperature dependence models are a linear relation for the refractive index and an Arrhenius relation for the dynamic viscosity of each liquid. Then the dynamic viscosity of the mixture is represented with a Grunberg-Nissan model of type 1. Experimental tests for acrylic and blood viscosity were found to be in very good agreement with the targeted values (measured refractive index of 1.486 and kinematic viscosity of 3.454 milli-m2/s with targeted values of 1.47 and 3.300 milli-m2/s).
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100
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Dickerman RD, Stevens QE, Rak R, Dorman SE, Holland SM, Nguyen TT. Isolated intracranial infection with Mycobacterium avium complex. J Neurosurg Sci 2003; 47:101-5; discussion 105. [PMID: 14618138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
UNLABELLED Mycobacterium avium-M. complex (MAC) has been linked to devastating respiratory and systemic illnesses in patients, especially in those who are immunosuppressed. The purpose of this study is to describe a case of isolated central nervous system (CNS) infection with MAC. This is a single case report of a patient with isolated intracranial mycobacterial infection. SETTING the patient was treated and the immunohistochemical investigations were undertaken at the National Institutes of Health in Bethesda, Maryland, USA. INTERVENTION the patient initially was treated with a cocktail of antimycobacterial medications. However, because his disease was refractory, he underwent a suboccipital craniotomy and evacuation of his cerebellar mass. The patient was determined to have a low production of interferon-gamma (INF-gamma) and tumor necrosis factor-alpha (TNF-alpha) when compared to normal values. Despite extensive radiographic imaging studies and biopsies, there was no evidence of another focus of MAC infection in this patient. We conclude that intracranial infectious lesions in patients such as ours should be treated with conventional systemic antibiotic regimens as the first-line of therapy. We suggest neurosurgical intervention in medically refractory cases of intracranial infections.
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