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Torrego A, Haque RA, Nguyen LT, Hew M, Carr DH, Wilson R, Chung KF. Capsaicin cough sensitivity in bronchiectasis. Thorax 2006; 61:706-9. [PMID: 16601085 PMCID: PMC2104708 DOI: 10.1136/thx.2005.049767] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Bronchiectasis is a suppurative airway disease characterised by persistent cough and sputum production associated with bronchial dilatation. A study was undertaken to determine whether cough sensitivity is increased in bronchiectatic patients. METHODS Twenty two patients with bronchiectasis and 20 healthy non-smoking controls matched for age and sex were recruited into the study. Quality of life (Leicester Cough Questionnaire score), total cough symptom score, and extent of bronchiectasis on HRCT scans were recorded. Cough sensitivity was assessed using incremental inhalation of capsaicin concentrations; the concentration at which 5 or more coughs occurred (C5) was recorded. RESULTS Patients with bronchiectasis had increased sensitivity to capsaicin compared with controls (mean (SE) log10 C5 1.22 (0.20) v 1.89 (0.21); p<0.03). Capsaicin sensitivity correlated positively with the Leicester Cough Questionnaire score (r = 0.64; p = 0.005) and inversely with the total cough symptom score (r = -0.58; p = 0.004), but not with the extent of the disease. It also correlated with forced expiratory volume in 1 second (FEV1) in litres (r = 0.58; p = 0.005) but not with FEV1 % predicted. Capsaicin sensitivity was not related to the presence of infected sputum or to corticosteroid or bronchodilator use. CONCLUSIONS : Patients with bronchiectasis have a sensitive cough reflex which reflects the severity of cough symptoms. A measure of cough severity could be part of health assessment for patients with bronchiectasis.
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Srinivasan V, Nam HM, Nguyen LT, Tamilselvam B, Murinda SE, Oliver SP. Prevalence of Antimicrobial Resistance Genes inListeria monocytogenesIsolated from Dairy Farms. Foodborne Pathog Dis 2005; 2:201-11. [PMID: 16156701 DOI: 10.1089/fpd.2005.2.201] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Antimicrobial resistance of Listeria monocytogenes (n = 38) isolated from the four dairy farms to 15 antimicrobial agents was evaluated. All 38 L. monocytogenes isolates from the four farms evaluated were resistant to more than one antimicrobial in different combinations. All L. monocytogenes isolates evaluated were resistant to cephalosporin C (minimum inhibitory concentration [MIC] > or = 512 microg/mL), streptomycin (MIC > or = 32) and trimethoprim (MIC > or = 512). Most L. monocytogenes isolates were resistant to ampicillin (92%, MIC > or = 2), rifampicin (84%, MIC > or = 4), rifamycin (84%, MIC > or = 4), and florfenicol (66%, MIC > or = 32) and some were resistant to tetracycline (45%, MIC > or = 16), penicillin G (40%, MIC > or = 2) and chloramphenicol (32%, MIC > or = 32). All L. monocytogenes isolates were susceptible to amoxicillin, erythromycin, gentamicin, kanamycin and vancomycin. Susceptibility of L. monocytogenes to the antimicrobials evaluated was quite consistent among the dairy farms evaluated. However, some variability in antimicrobial susceptibility among dairy farms was noted. Nineteen of 38 L. monocytogenes isolates contained more than one antimicrobial resistance gene sequence. A high frequency of floR (66%) was found in L. monocytogenes followed by penA (37%), strA (34%), tetA (32%), and sulI (16%). Other tetracycline resistance genes (tetB, tetC, tetD, tetE, and tetG) and other antimicrobial resistance genes (cmlA, strB, aadA, sulI, vanA, vanB, ampC, ermB, ereA, and ereB) were not found in any of the L. monocytogenes isolates from the four dairy farms. Results of the present study demonstrated that L. monocytogenes isolated from the dairy farm environment were resistant to many antimicrobials and contained one or more antimicrobial resistance genes.
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Nguyen LT, Gillespie BE, Nam HM, Murinda SE, Oliver SP. Detection ofEscherichia coliO157:H7 andListeria monocytogenesin Beef Products by Real-Time Polymerase Chain Reaction. Foodborne Pathog Dis 2004; 1:231-40. [PMID: 15992285 DOI: 10.1089/fpd.2004.1.231] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Rapid methods for the detection of Escherichia coli O157:H7 and Listeria monocytogenes in food products are important to the food industry and for public health. Conventional microbiological methods and newly developed molecular-based techniques such as polymerase chain reaction (PCR)-based methods are time consuming. In this study, a faster method based on utilization of a hybridization probe with real-time PCR, was developed and applied for detection of E. coli O157:H7 and L. monocytogenes from artificially contaminated raw ground beef and fully cooked beef hotdogs. Target genes for E. coli O157:H7 and L. monocytogenes were rfbE and hylA, respectively. An analysis of 169 bacterial strains showed that the chosen primers and probes were specific for detection of E. coli O157:H7 and L. monocytogenes by real-time PCR. The assay was positive for nine of 10. E. coli O157:H7 strains, and all L. monocytogenes (7/7) strains evaluated. Bacterial strains lacking these genes were not detected by these assays. Detection limits of real-time PCR assays ranged from 10(3) to 10(8) colony forming units (CFU)/ml for E. coli O157:H7 in modified tryptic soy broth and 10(4) to 10(8) CFU/mL for L. monocytogenes in Fraser Broth. Detection sensitivity ranged from 10(3) to 10(4) CFU/g of raw ground beef or hotdog without enrichment for E. coli and L. monocytogenes. Approximately 1.4-2.2 CFU/g of E. coli O157:H7 in raw ground beef were detected following an enrichment step of 4 h. Approximately 1.2-6.0 CFU/g of L. monocytogenes in beef hotdogs were detected following an enrichment step of 30 h. The real-time PCR assays for detection of E. coli O157:H7 and L. monocytogenes in raw ground beef and beef hotdogs were specific, sensitive and rapid.
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Niimi A, Nguyen LT, Usmani O, Mann B, Chung KF. Reduced pH and chloride levels in exhaled breath condensate of patients with chronic cough. Thorax 2004; 59:608-12. [PMID: 15223872 PMCID: PMC1747079 DOI: 10.1136/thx.2003.012906] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Increased hydrogen and reduced chloride ionic environments of the airways are conducive to the stimulation of cough. However, the constituents of the local milieu of the airways of patients with chronic cough are unknown. METHODS The pH and chloride levels in exhaled breath condensate and capsaicin cough threshold (C5) were measured in 50 patients with chronic cough and in 16 healthy controls. pH and chloride measurements were repeated after capsaicin challenge in those with cough. The cause of cough was asthma (n = 13), postnasal drip/rhinitis (n = 7), gastro-oesophageal reflux (n = 5), bronchiectasis (n = 5), but remained unidentified in 20. RESULTS Compared with controls, patients with chronic cough had lower pH (mean 7.9 v 8.3, 95% CI of difference -0.5 to -0.2, p<0.0001), chloride levels (median 4 v 6 mmol/l, 95% CI -3.1 to -0.2, p = 0.007), and C5 (median 3.9 v 125 micro M, 95% CI -270.0 to -17.6, p = 0.002). The pH levels were different in the six subgroups including controls, and were reduced in all diagnostic subgroups of patients with cough compared with controls but did not differ between them. Chloride levels were significantly different in the six subgroups but were lower than controls in only the gastro-oesophageal reflux subgroup. There was a weak but significant correlation between chloride levels and C5 when all participants were analysed together, but not between pH and C5 or chloride levels. pH and chloride levels did not change after capsaicin challenge. CONCLUSIONS The epithelial lining fluid of patients with chronic cough has a reduced pH and reduced chloride levels which could contribute to the enhanced cough reflex.
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Nakamura M, Tohya Y, Miyazawa T, Mochizuki M, Phung HTT, Nguyen NH, Huynh LMT, Nguyen LT, Nguyen PN, Nguyen PV, Nguyen NPT, Akashi H. A novel antigenic variant of Canine parvovirus from a Vietnamese dog. Arch Virol 2004; 149:2261-9. [PMID: 15503211 DOI: 10.1007/s00705-004-0367-y] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2004] [Accepted: 04/29/2004] [Indexed: 10/26/2022]
Abstract
Nine isolates of Canine parvovirus (CPV) were obtained from Vietnamese dogs and cats. One canine isolate showed a unique antigenic property which indicates a novel antigenic variant of CPV-2b when examined with hemagglutination inhibition tests using our monoclonal antibodies, 21C3 and 19D7, which were recently developed. This isolate had an amino acid substitution of residue 426, Asp to Glu, and the same substitution has recently been found in CPV from Italian dogs. This study first showed that such substitution caused an antigenic difference demonstrable by monoclonal antibodies and that a similar evolution may have occurred in CPV in Vietnam.
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Murinda SE, Nguyen LT, Nam HM, Almeida RA, Headrick SJ, Oliver SP. Detection of Sorbitol-Negative and Sorbitol-Positive Shiga Toxin-ProducingEscherichia coli,Listeria monocytogenes,Campylobacter jejuni, andSalmonellaspp. in Dairy Farm Environmental Samples. Foodborne Pathog Dis 2004; 1:97-104. [PMID: 15992268 DOI: 10.1089/153531404323143611] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Six visits were conducted to four dairy farms to collect swab, liquid, and solid dairy farm environmental samples (165 to 180/farm; 15 sample types). The objective of the study was to determine on-farm sources of Campylobacter jejuni, Salmonella spp., Listeria monocytogenes, and Shiga toxin-producing Escherichia coli (STEC), which might serve as reservoirs for transmission of pathogens. Samples were analyzed using mostly U.S. Food and Drug Administration's Bacteriological Analytical Manual protocols; however, Salmonella spp., L. monocytogenes and STEC were co-enriched in universal pre-enrichment broth. Campylobacter jejuni were enriched in Bolton broth containing Bolton broth supplement. Pathogens were isolated on agar media, typed biochemically, and confirmed using multiplex polymerase chain reaction protocols. Campylobacter jejuni, Salmonella spp., L. monocytogenes, Sorbitol-negative (SN)-STEC O157:H7, and sorbitol-positive (SP)-STEC, respectively, were isolated from 5.06%, 3.76%, 6.51%, 0.72%, and 17.3% of samples evaluated. Whereas other pathogens were isolated from all four farms, SN-STEC O157:H7 were isolated from only two farms. Diverse serotypes of SP-STEC including O157:H7, O26:H11, O111, and O103 were isolated. None of the five pathogen groups studied were isolated from bulk tank milk (BTM). Most pathogens (44.2%) were isolated directly from fecal samples. Bovine fecal samples, lagoon water, bedding, bird droppings, and rat intestinal contents constituted areas of major concern on dairy farms. Although in-line milk filters from two farms tested positive for Salmonella or L. monocytogenes, none of the pathogens were detected in the corresponding BTM samples. Good manure management practices, including control of feral animals, are critical in assuring dairy farm hygiene. Identification of on-farm pathogen reservoirs could aid with implementation of farm-specific pathogen reduction programs.
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Nam HM, Murinda SE, Nguyen LT, Oliver SP. Evaluation of Universal Pre-Enrichment Broth for Isolation ofSalmonellaspp.,Escherichia coliO157:H7, andListeria monocytogenesfrom Dairy Farm Environmental Samples. Foodborne Pathog Dis 2004; 1:37-44. [PMID: 15992260 DOI: 10.1089/153531404772914446] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Use of universal pre-enrichment broth (UPB) as a primary enrichment medium for detection of Salmonella spp., Escherichia coli O157:H7, and Listeria monocytogenes from dairy farm environmental samples was evaluated. There were no differences in bacterial growth between UPB and selective primary enrichment broths for each pathogen inoculated individually or in combination at 10(1) and 10(2) colony forming units/mL. In addition, no differences were observed when UPB and selective primary enrichment broths were compared for detection efficiency of pathogens in artificially contaminated raw milk and fecal samples. Listeria enrichment broth (LEB) was compared with UPB to support growth of L. monocytogenes from naturally contaminated environmental samples. Listeria monocytogenes was isolated from seven of 30 samples enriched in UPB and six of 30 samples enriched in LEB. Dairy farm environmental samples were examined for recovery of the three pathogens using UPB. Subsequent isolation was achieved using selective secondary enrichment of each pathogen. Listeria monocytogenes, Salmonella spp., and E. coli O157:H7 were isolated in 13.4% (30 of 224), 8.9% (20 of 224), and 2.2% (five of 224) of samples, respectively. Isolation rates of the three pathogens were somewhat higher than in previous reports. Overall, UPB supported growth of test pathogens to detectable levels within 24 h. Our results demonstrate that UPB has potential for routine use in isolation of foodborne pathogens from diverse environmental samples.
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Jouaville LF, Annesi-Maesano I, Nguyen LT, Bocage AS, Bedu M, Caillaud D. Interrelationships among asthma, atopy, rhinitis and exhaled nitric oxide in a population-based sample of children. Clin Exp Allergy 2004; 33:1506-11. [PMID: 14616861 DOI: 10.1046/j.1365-2222.2003.01800.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Exhaled nitric oxide (eNO) has attracted increasing interest as a non-invasive marker of airway inflammation in asthma. However, little evidence exists on the influences exerted on eNO by the interrelations among atopic status, asthma and rhinitis. METHODS Among the 1156 children who participated in a large-scale epidemiological survey on asthma and allergies (ISAAC II: International Study of Asthma and Allergies in Childhood Phase II) in the city of Clermont-Ferrand, 53 asthmatics without corticosteroid treatment and 96 non-asthmatics were invited to perform eNO and skin prick tests (SPTs) to 12 common allergens. RESULTS Atopic asthmatic children had higher eNO than non-atopic asthmatic children (28.9+/-9.1 vs. 17.1+/-13.1 p.p.b.; P=0.0004) with a significant increase when one SPT or more are positive (26.5+/-7.8 vs. 17.1+/-13.1 p.p.b.; P=0.03). Similarly, non-asthmatic, atopic subjects had higher eNO than non-atopic subjects with a significant increase when two SPTs or more are positive (19.4+/-9.8 vs. 11.7 +/-6.7 p.p.b.; P=0.003). In the case of equal levels of positive SPTs (0, 1, >/=2), asthmatic children always had higher eNO than non-asthmatic ones. Furthermore, among non-asthmatic children, the eNO level increased only in atopics who had rhinitis (20.7+/-13 vs. 12.5+/-6.4 p.p.b. in atopic controls (subjects without rhinitis and asthma) and 12.3+/-6.6 p.p.b. in non-atopic controls; P=0.001), whereas among asthmatic children, eNO level increased in atopics independently of rhinitis (28.2+/-9.5 p.p.b. in those with rhinitis and 30.9+/-8.1 p.p.b. in those without) as well as in non-atopics with rhinitis (22.5+/-17.2 p.p.b.). CONCLUSIONS Our data suggest that besides atopy and asthma, allergic rhinitis should also be taken into account in the assessment of eNO.
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Gerhard DS, Nguyen LT, Zhang ZY, Borecki IB, Coleman BI, Rader JS. A relationship between methylenetetrahydrofolate reductase variants and the development of invasive cervical cancer. Gynecol Oncol 2003; 90:560-5. [PMID: 13678724 DOI: 10.1016/s0090-8258(03)00368-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
OBJECTIVE Low red blood cell folate levels have been associated with hypomethylation of DNA in dysplastic tissue and an increased risk for cervical intraepithelial neoplasia in human papillomavirus (HPV)-infected women. Methylenetetrahydrofolate reductase (MTHFR) is a critical enzyme regulating the metabolism of folate and methionine, the important components of DNA synthesis and methylation. Two common genetic polymorphisms, causing reduced MTHFR activity, have been identified. Therefore, the goal of this study was to evaluate these MTHFR variations as risk factors for invasive cervical cancer. METHODS To overcome the failure to properly match cases and controls that can cause false-positive inferences due to population stratification and unrecognized variables in a traditional case-control study, a family-based transmission/disequilibrium test (TDT) was used. We obtained samples from nuclear families of 102 women with invasive cervical cancer (ICC). One polymorphism was typed by a PCR-RFLP method, while a template-directed dye-terminator assay was developed for the other. RESULTS AND CONCLUSIONS We were unable to confirm a strong association of MTHFR polymorphisms and ICC using family-based controls and a transmission/disequilibrium test. The overall results of the TDT showed chi(2) (1 df) of 0.28 (P = 0.60) for exon 4, chi(2) (1 df) of 0.81(P = 0.37) for exon 7, and chi(2) (3 df) of 2.56 (P = 0.46) for the haplotype, meaning that there was no transmission of those alleles significantly in excess of Mendelian expectations to affected women. In addition, there was no effect of these variants with increased parity or infection with high-risk-type human papillomavirus.
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Puligandla PS, Nguyen LT, St-Vil D, Flageole H, Bensoussan AL, Nguyen VH, Laberge JM. Gastrointestinal duplications. J Pediatr Surg 2003; 38:740-4. [PMID: 12720184 DOI: 10.1016/jpsu.2003.50197] [Citation(s) in RCA: 137] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
BACKGROUND/PURPOSE The aim of this study was to review the presentations of gastrointestinal duplication (GID) and to assess the influence of prenatal diagnosis on treatment. METHODS Retrospective review of all GID at 2 pediatric hospitals from 1980-2002 was conducted. RESULTS Seventy-three patients (M43:F30) were identified: 21 neonates, 28 infants (1 to 24 months), 15 children (1 to 10 years), 9 adolescents (>/=11 years). GID location by frequency was ileum (31.5%), ileocaecal valve (30.2%), duodenum (9.6%), stomach (8.2%), jejunum (8.2%), colon (6.8%), and rectum (5.5%). In neonates and infants, vomiting and distension were the most common presentations. Volvulus, caused by a duplication, occurred in 23.8% of neonates and caused the death of one neonate. Intussusception was identified in 10.9% of patients. In older children and adolescents, pain and vomiting were the most common associations. Six of these patients were being treated for Crohn's disease, with the diagnosis of duplication made at laparotomy. Eighteen patients had a prenatal diagnosis by ultrasound scan, with 77.2% of these asymptomatic after birth. Most prenatal diagnoses occurred after 1991 (77.8%). When comparing an earlier period (1980 to 1991; 29 patients) with the current (1992 to 2002; 44 patients), a greater proportion of the latter patients were asymptomatic (36.4 v 13.8%) and had a lower incidence of complications (volvulus/intussusception). CONCLUSIONS GID can lead to life-threatening complications. Prenatal diagnosis should lead to expeditious postnatal investigation and treatment before the onset of symptoms or complications. GID in older children can mimic Crohn's disease. Laparoscopy/laparotomy should be considered in patients with atypical Crohn's disease or when the diagnosis of an intraabdominal mass is unclear.
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Nguyen LT, Bachmann MF, Ohashi PS. Contribution of LCMV transgenic models to understanding T lymphocyte development, activation, tolerance, and autoimmunity. Curr Top Microbiol Immunol 2002; 263:119-43. [PMID: 11987812 DOI: 10.1007/978-3-642-56055-2_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Murinda SE, Nguyen LT, Ivey SJ, Gillespie BE, Almeida RA, Draughon FA, Oliver SP. Molecular characterization of Salmonella spp. isolated from bulk tank milk and cull dairy cow fecal samples. J Food Prot 2002; 65:1100-5. [PMID: 12117241 DOI: 10.4315/0362-028x-65.7.1100] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The consumption of meat from cull dairy cows and of raw milk has been associated with foodborne salmonellosis. This survey was conducted to establish the prevalence of Salmonella in cull dairy cow fecal samples and bulk tank milk and to determine the proportion of Salmonella-positive dairy farms (n = 30) in east Tennessee. Food and Drug Administration bacteriological analytical protocols were generally used for Salmonella isolation. Primary enrichment was performed with lactose broth, and secondary enrichment was conducted with tetrathionate broth. Eosin methylene blue, hektoen enteric, xylose lysine desoxycholate, bismuth sulfite, and brilliant green (BG) were used as isolation agars. BG agars supplemented with individual antibiotics and/or sulfur compounds were also evaluated. Six of 268 (2.24%) bulk tank milk samples and 9 of 415 (2.17%) fecal samples from 7 of 30 (25.3%) dairy farms were Salmonella-positive. Most isolates (11 of 15) were obtained between September and December. Salmonella isolates were further characterized using polyvalent somatic O Salmonella antiserum, o-nitrophenyl-beta-D-galactopyranoside (ONPG), and Analytical Profile Index (API) 20E strips for Enterobacteriaceae. Serological evaluation of presumptive positive Salmonella isolates resulted in substantial numbers of false positives (41.2%). ONPG and API 20E tests enabled further biochemical distinction of the majority of Salmonella spp. from Salmonella Arizonae and closely related members of Enterobacteriaceae like Citrobacter youngae. Pulsed-field gel electrophoresis of SpeI-digested Salmonella DNA was used to subtype isolates. The isolates grouped into four clusters. The baseline information generated in this survey is being used to develop preharvest pathogen reduction programs on selected farms.
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Murinda SE, Nguyen LT, Ivey SJ, Gillespie BE, Almeida RA, Draughon FA, Oliver SP. Prevalence and molecular characterization of Escherichia coli O157:H7 in bulk tank milk and fecal samples from cull cows: a 12-month survey of dairy farms in east Tennessee. J Food Prot 2002; 65:752-9. [PMID: 12030284 DOI: 10.4315/0362-028x-65.5.752] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A study on the prevalence of Escherichia coli O157:H7 was conducted on 30 dairy farms in east Tennessee between May 2000 and April 2001. This pathogen was isolated from 8 of 30 (26.7%) dairy farms at various sampling times. A total of 415 fecal samples from cull dairy cows and 268 bulk tank milk samples were analyzed. Overall, 10 of 683 (1.46%) samples (2 of 268 [0.75%] milk samples and 8 of 415 [1.93%] fecal samples) tested positive for E. coli O157:H7. Food and Drug Administration Bacteriological Analytical Manual protocols were used for the conventional isolation and confirmation of E. coli O157:H7. Samples were shake cultured (150 rpm) at 42 degrees C for 24 h in tryptic soy broth containing 2 mg of novobiocin per liter. White colonies isolated on cefixime-tellurite sorbitol MacConkey agar plates were evaluated for fluorescence on sorbitol MacConkey agar supplemented with 0.025 g of methylumbelliferyl-beta-D-glucuronide per liter. Nonfluorescing white colonies were biochemically typed and serologically confirmed. Multiplex polymerase chain reaction profiles of E. coli O157:H7 isolates indicated the presence of common virulence factors (Shiga toxin, enterohemolysin, and intimin) of Shiga toxin-producing E. coli, suggesting the potential human pathogenicity of bacterial isolates. Pulsed-field gel electrophoresis profiles of SpeI and XbaI restriction enzyme-digested genomic DNA were used to establish relatedness among bacterial isolates. Data from this study indicate that both cull dairy cows and bulk tank milk pose a potential hazard with regard to human foodborne illness. It is therefore imperative to develop on-farm and preharvest pathogen reduction programs to control the carriage of E. coli O157:H7 pathogens.
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Garza KM, Nguyen LT, Jones RG, Ohashi PS. Factors contributing to autoimmune disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2002; 490:7-19. [PMID: 11505977 DOI: 10.1007/978-1-4615-1243-1_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
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Nguyen LT, Durocher Y, Chapdelaine A, Chevalier S. The major form of protein tyrosine kinase in the dog prostate is expressed by a 50 kDa polypeptide. FEBS Lett 2002; 296:215-8. [PMID: 1370804 DOI: 10.1016/0014-5793(92)80382-q] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
We have already reported that the protein tyrosine kinase (PTK) activity in the dog prostate is distributed in cytosolic (75%) and particulate (Triton X-100-solubilized) fractions and that upon gel filtration, both PTKs migrate as entities of Mr 44,000 [(1991) Biochem. Cell. Biol. 69, 146-153]. Herein we demonstrate by immunoprecipitation with anti-phosphotyrosine antibodies that the soluble PTK has the ability to undergo self-phosphorylation. In addition, the polypeptide responsible for that enzymatic activity has been identified by 2 approaches: (1) a two-dimensional electrophoresis, in which the first dimension performed in non-denaturing conditions allowed the localization of the native enzyme, while the second dimension (SDS-PAGE) permitted the analysis of alkali-resistant phosphoproteins corresponding to the activity; (2) protein renaturation after SDS-PAGE followed by in situ phosphorylation (with [gamma-32P]ATP) of polyGT electrophoresed together with the enzyme preparation; the exclusive presence of the radiolabeled phosphotyrosine in the renatured protein confirmed its enzymatic nature. Using these methods, the major form of PTK in the dog prostate was shown to be expressed by a 50 kDa polypeptide which possesses autophosphorylation sites and which is present in the cytosol as an active monomer.
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Folcher M, Gaillard H, Nguyen LT, Nguyen KT, Lacroix P, Bamas-Jacques N, Rinkel M, Thompson CJ. Pleiotropic functions of a Streptomyces pristinaespiralis autoregulator receptor in development, antibiotic biosynthesis, and expression of a superoxide dismutase. J Biol Chem 2001; 276:44297-306. [PMID: 11557748 DOI: 10.1074/jbc.m101109200] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In Streptomyces, a family of related butyrolactones and their corresponding receptor proteins serve as quorum-sensing systems that can activate morphological development and antibiotic biosynthesis. Streptomyces pristinaespiralis contains a gene cluster encoding enzymes and regulatory proteins for the biosynthesis of pristinamycin, a clinically important streptogramin antibiotic complex. One of these proteins, PapR1, belongs to a well known family of Streptomyces antibiotic regulatory proteins. Gel shift assays using crude cytoplasmic extracts detected SpbR, a developmentally regulated protein that bound to the papR1 promoter. SpbR was purified, and its gene was cloned using reverse genetics. spbR encoded a 25-kDa protein similar to Streptomyces autoregulatory proteins of the butyrolactone receptor family, including scbR from Streptomyces coelicolor. In Escherichia coli, purified SpbR and ScbR produced bound sequences immediately upstream of papR1, spbR, and scbR. SpbR DNA-binding activity was inhibited by an extracellular metabolite with chromatographic properties similar to those of the well known gamma-butyrolactone signaling compounds. DNase I protection assays mapped the SpbR-binding site in the papR1 promoter to a sequence homologous to other known butyrolactone autoregulatory elements. A nucleotide data base search showed that these binding motifs were primarily located upstream of genes encoding Streptomyces antibiotic regulatory proteins and butyrolactone receptors in various Streptomyces species. Disruption of the spbR gene in S. pristinaespiralis resulted in severe defects in growth, morphological differentiation, pristinamycin biosynthesis, and expression of a secreted superoxide dismutase.
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Camara JG, Nguyen LT, Fernandez-Suntay JP, Nardin GF, Sua AS. The use of a computer-assisted image-guided system (InstaTrak) in orbital surgery. Ophthalmic Plast Reconstr Surg 2001; 17:447-51. [PMID: 11766027 DOI: 10.1097/00002341-200111000-00012] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE To assess the usefulness of a computer-assisted image-guided system (CAIGS) as an intraoperative anatomical guide in performing orbital surgery. METHODS Noncomparative interventional case series of 30 consecutive orbital procedures performed by one surgeon (J.G.C.) using the CAIGS (InstaTrak) for intraoperative anatomical guidance. RESULTS The series consisted of 8 cases of orbital decompression, 8 cases of orbital fracture, 11 cases of tumor excision, 2 cases of orbital reconstruction for severe enophthalmos, and 1 case of drainage of an orbital abscess. The CAIGS (InstaTrak) was useful in providing adjunctive intraoperative guidance in all 30 orbital cases. CONCLUSION The CAIGS (InstaTrak) system is a useful adjunctive tool in providing intraoperative anatomic guidance in a consecutive series of varied orbital operations.
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Nguyen LT, Proft FD, Chandra AK, Uchimaru T, Nguyen MT, Geerlings P. Nitrous oxide as a 1,3-dipole: a theoretical study of its cycloaddition mechanism. J Org Chem 2001; 66:6096-103. [PMID: 11529736 DOI: 10.1021/jo015685f] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The 1,3-dipolar cycloadditions of nitrous oxide and substituted alkynes have been studied at the B3LYP/6-31G(d,p) level. The reaction is controlled by LUMO (dipole)--HOMO (dipolarofile) and involves aromatic transition structures. The shape of the potential energy surface and the regioselectivity are not affected by the polarity of the solvents, except in the case of N2O + HC triple bond CSiH3. Different reactivity criteria including FMO coefficients product C, local softness differences Delta, magnetic susceptibility anisotropy chi(anis), and nucleus-independent chemical shifts NICS were used to predict the regioselectivity in all studied cases; the C, Delta criteria turn out to give the best results among them. The aromaticity of the transition structure is not a factor in determining the regiochemistry of the cycloaddtition reactions.
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Garren H, Ruiz PJ, Watkins TA, Fontoura P, Nguyen LT, Estline ER, Hirschberg DL, Steinman L. Combination of gene delivery and DNA vaccination to protect from and reverse Th1 autoimmune disease via deviation to the Th2 pathway. Immunity 2001; 15:15-22. [PMID: 11485734 DOI: 10.1016/s1074-7613(01)00171-6] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Using a combination of local gene delivery and tolerizing DNA vaccination, we demonstrate that codelivery of the interleukin-4 (IL-4) gene and a DNA vaccine encoding the self-peptide proteolipid protein 139-151 (PLP139-151) provides protective immunity against experimental autoimmune encephalomyelitis (EAE). We provide evidence for a mechanism whereby IL-4 expressed from the naked DNA is secreted and acts locally on autoreactive T cells via activation of STAT6 to shift their cytokine profile to T helper 2. We also show that DNA vaccines can be used to reverse established EAE by covaccination with the genes for myelin oligodendrocyte glycoprotein and IL-4. This treatment strategy combines the antigen-specific effects of DNA vaccination and the beneficial effects of local gene delivery.
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Nguyen LT, De Proft F, Nguyen MT, Geerlings P. Theoretical Study of [2 + 1] cycloaddition of CO and CS to acetylenes forming cyclopropenones and cyclopropenethiones. J Org Chem 2001; 66:4316-26. [PMID: 11397170 DOI: 10.1021/jo015584h] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The [2 + 1] cycloadditions of carbon monoxide and carbon monothioxide CX (X = O, S) to acetylenes (R1C triple bond CR2 with R1 = H, OH and R2 = CH3, OH, NH2, C6H5) have been studied at the B3LYP/6-311G(d,p) level. It has been shown that the reaction proceeds in two steps forming first an intermediate having the properties of both a carbene and a zwitterion followed by a ring closure leading to cyclopropenones or cyclopropenethiones. The solvent effect does not play an important role in the course of the cycloaddition. The estimation of the first vertical excitation energies by CIS and TD-B3LYP methods shows that the reactions likely take place in the ground state rather than in an excited state. All the studied cyclopropenones and cyclopropenethiones are aromatic as shown by their NICS values and confirmed by calculated and experimental NMR chemical shifts. Different reactivity criteria including HOMO coefficient, local softness, hardness, polarizability, and NICS are used to predict the site selectivity in all studied cases, and the NICS criterion seems to yield the best results among them.
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Thompson AA, Woodruff K, Feig SA, Nguyen LT, Schanen NC. Congenital thrombocytopenia and radio-ulnar synostosis: a new familial syndrome. Br J Haematol 2001; 113:866-70. [PMID: 11442476 DOI: 10.1046/j.1365-2141.2001.02834.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The association of bone marrow failure and skeletal defects has been frequently noted, however, the genetic basis for most of these syndromes remains unclear. We describe a previously uncharacterized autosomal dominant syndrome of amegakaryocytic thrombocytopenia associated with radial-ulnar synostosis. The clinical features of this syndrome appear to be distinct from other similar conditions, including Fanconi's anaemia and thrombocytopenia-absent radii (TAR). The physical findings at diagnosis and clinical management of each case are detailed, as well as a discussion of this disorder in the context of other syndromes in which marrow failure and skeletal defects are prominent features. We also review recent developments in molecular genetics that may provide important clues to the underlying aetiology of this condition.
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Ramanathan M, Weinstock-Guttman B, Nguyen LT, Badgett D, Miller C, Patrick K, Brownscheidle C, Jacobs L. In vivo gene expression revealed by cDNA arrays: the pattern in relapsing-remitting multiple sclerosis patients compared with normal subjects. J Neuroimmunol 2001; 116:213-9. [PMID: 11438176 DOI: 10.1016/s0165-5728(01)00308-3] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
OBJECTIVES To use DNA arrays to identify differences in gene expression associated with relapsing-remitting (RR) MS. METHODS Total RNA was isolated from monocyte depleted peripheral blood mononuclear cells of 15 RR MS patients and 15 age- and sex-matched controls. The RNA was reverse transcribed to radiolabeled cDNA and the resultant cDNA was used to probe a DNA array containing over 4000 named human genes. The binding of radiolabeled cDNA to the probes on the array was measured by phosphorimager. RESULTS Of more than 4000 genes tested, only 34 were significantly different in RR-MS patients from controls. Of these, 25 were significantly increased and 9 significantly decreased in the RR MS patients. Twelve of these genes have inflammatory and/or immunological functions that could be relevant to the MS disease process. The potentially relevant genes that were elevated (15% to 28%) were P protein, LCK, cAMP responsive element modulator, IL-7 receptor, matrix metalloproteinase-19, M130 antigen, and peptidyl-prolyl isomerase. Those that were significantly decreased (15% to 35%) were SAS transmembrane 4 superfamily protein, STRL22 (C-C chemokine receptor 6), AFX protein, DNA fragmentation factor-45 and immunoglobulin gamma 3 (Gm marker). CONCLUSIONS The RR-MS disease effect was relatively restricted and most of the mRNAs tested were not different from the normal controls. However, there were significant differences identified in the expression of a subset of mRNAs, including 13 with inflammatory/immune functions that could be relevant to MS. The systematic use of DNA arrays can provide insight into the dynamic cellular pathways involved in MS pathogenesis and its phenotypic heterogeneity.
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MESH Headings
- Adult
- Agglutinins/genetics
- Antigens, CD
- Antigens, Differentiation, Myelomonocytic/genetics
- Apoptosis Regulatory Proteins
- Carrier Proteins/genetics
- Cell Cycle Proteins
- Cyclic AMP Response Element Modulator
- DNA, Complementary
- DNA-Binding Proteins/genetics
- Female
- Forkhead Transcription Factors
- Gene Expression/immunology
- Glycoproteins/genetics
- Humans
- Immunoglobulin G/genetics
- Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/genetics
- Male
- Matrix Metalloproteinases, Secreted
- Membrane Proteins/genetics
- Membrane Transport Proteins
- Metalloendopeptidases/genetics
- Middle Aged
- Multiple Sclerosis, Relapsing-Remitting/genetics
- Multiple Sclerosis, Relapsing-Remitting/immunology
- Oligonucleotide Array Sequence Analysis
- Peptidylprolyl Isomerase/genetics
- Proteins/genetics
- Receptors, CCR6
- Receptors, Cell Surface/genetics
- Receptors, Chemokine
- Receptors, Cytokine/genetics
- Receptors, Interleukin-7/genetics
- Repressor Proteins
- Transcription Factors/genetics
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Hagr A, Laberge JM, Nguyen LT, Emil S, Bernard C, Patenaude Y. Laparoscopic excision of subdiaphragmatic epidermoid cyst: a case report. J Pediatr Surg 2001; 36:E8. [PMID: 11381451 DOI: 10.1053/jpsu.2001.24021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Retroperitoneal epidermoid cysts are rare. The authors report a case of an 11-year-old boy with an asymptomatic subdiaphragmatic cyst, which was found incidentally during an investigation for hypertension. At laparoscopy, the cyst was densely adherent to the diaphragm, resulting in a pneumothorax during dissection. Nevertheless, the excision and the diaphragmatic repair could be completed laparoscopically without complication. Microscopic examination showed an epidermoid cyst. No similar case has been reported in the literature.
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Emil S, Mikhail P, Laberge JM, Flageole H, Nguyen LT, Shaw KS, Baican L, Oudjhane K. Clinical versus sonographic evaluation of acute appendicitis in children: a comparison of patient characteristics and outcomes. J Pediatr Surg 2001; 36:780-3. [PMID: 11329589 DOI: 10.1053/jpsu.2001.22960] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE Abdominal sonography has gained popularity in establishing the diagnosis of appendicitis in children with equivocal clinical presentations. However, no clear outcome benefits have been demonstrated to date. The authors conducted a retrospective study to compare the characteristics and outcomes of patients undergoing appendectomy after clinical evaluation only with those undergoing the procedure after sonography. METHODS The charts of 454 consecutive patients undergoing appendectomy for acute appendicitis between January 1, 1998 and December 4, 1999 were reviewed. Patients operated on after clinical evaluation only were compared with patients operated on after abdominal sonography. RESULTS Forty-two percent of patients (n = 191) constituted the sonography group. When compared with the clinical group, these patients had higher prevalence of female gender (52% v 38%; P =.004), longer symptom duration (2.2 +/- 2.5 v 1.6 +/- 1.6 days; P =.003), higher incidence of preoperative in-patient observation (19% v 4%; P <.001), longer duration between evaluation and operation (8.0 +/- 3.9 v 4.9 +/- 2.9 hours; P <.001), higher incidence of normal appendices on pathologic examination (13% v 6%; P =.006), and higher incidence of postoperative abscesses or phlegmons (4.4% v 1.2%; P =.04). The groups did not differ significantly in age, hospital stay, incidence of complicated appendicitis, or incidence of wound infection. CONCLUSIONS Patients undergoing sonography before appendectomy have a longer delay before operation, a higher rate of misdiagnosis, and more postoperative complications. Limiting sonography to truly equivocal cases and using it early in the diagnostic workup may improve outcomes in this group of patients.
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Laurichesse H, Romaszko JP, Nguyen LT, Souweine B, Poirier V, Guólon D, André M, Ruivard M, De Champs C, Caillaud D, Labbé A, Beytout J. Clinical characteristics and outcome of patients with invasive pneumococcal disease, Puy-de-Dôme, France, 1994-1998. Eur J Clin Microbiol Infect Dis 2001; 20:299-308. [PMID: 11453589 DOI: 10.1007/pl00011269] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
A surveillance program for invasive pneumococcal disease was undertaken in Puyde-Dĵme, an administrative district of the region Auvergne in France, from 1 January 1994 to 31 December 1998. A total of 214 cases were identified. The annual incidence of invasive pneumococcal disease increased (P=0.04) from 5.5 in 1994 to 9.3 cases per 10(5) person-years in 1998. The highest incidences were for children <2 years of age (59.2 cases per 10(5) person-years) and for adults > or = 65 years (18 cases per 10(5) person-years). Clinical diagnoses, available in 200 patients, included acute pneumonia (62%), meningitis (10%), sepsis without focus (20%), and others (8%). The most frequent chronic medical conditions of the patients included smoking, alcoholism, cardiovascular and pulmonary diseases, and malignancies. Thirty-one percent of the isolates were nonsusceptible to penicillin. Penicillin resistance (MIC > or = 0.1 mg/l) was more frequent (P=0.02) in cancer patients. The overall case-fatality rate was 21.5%. Risk factors for death were age, sex, and underlying diseases of the patients, along with the severity of illness. These population-based findings should convince clinicians to offer pneumococcal vaccine to patients at high risk for invasive pneumococcal disease, thereby increasing vaccination coverage levels in France.
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