1
|
Chimen M, Kennedy A, Nirantharakumar K, Pang TT, Andrews R, Narendran P. What are the health benefits of physical activity in type 1 diabetes mellitus? A literature review. Diabetologia 2012; 55:542-51. [PMID: 22189486 DOI: 10.1007/s00125-011-2403-2] [Citation(s) in RCA: 287] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Accepted: 11/02/2011] [Indexed: 02/06/2023]
Abstract
Physical activity improves well-being and reduces the risk of heart disease, cancer and type 2 diabetes mellitus in the general population. In individuals with established type 2 diabetes, physical activity improves glucose and lipid levels, reduces weight and improves insulin resistance. In type 1 diabetes mellitus, however, the benefits of physical activity are less clear. There is poor evidence for a beneficial effect of physical activity on glycaemic control and microvascular complications, and significant risk of harm through hypoglycaemia. Here we review the literature relating to physical activity and health in type 1 diabetes. We examine its effect on a number of outcomes, including glycaemic control, lipids, blood pressure, diabetic complications, well-being and overall mortality. We conclude that whilst there is sufficient evidence to recommend physical activity in the management of type 1 diabetes, it is still unclear as to what form, duration and intensity should be recommended and whether there is benefit for many of the outcomes examined.
Collapse
|
Review |
13 |
287 |
2
|
Wakabayashi S, Pang T, Su X, Shigekawa M. A novel topology model of the human Na(+)/H(+) exchanger isoform 1. J Biol Chem 2000; 275:7942-9. [PMID: 10713111 DOI: 10.1074/jbc.275.11.7942] [Citation(s) in RCA: 168] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The membrane topology of the human Na(+)/H(+) exchanger isoform 1 (NHE1) was assessed by substituted cysteine accessibility analysis. Eighty-three cysteine residues were individually introduced into a functional cysteineless NHE1, and these mutants were expressed in the exchanger-deficient PS120 cells. The topological disposition of introduced cysteines was determined by labeling with a biotinylated maleimide in the presence or absence of preincubation with the membrane-impermeable sulfhydryl reagent, 2-trimethylammoniumethyl-methanethiosulfonate in streptolysin O-permeabilized or nonpermeabilized cells. We proposed a new model for the topology of NHE1 that is significantly different from the model derived from hydropathy analysis. In this model, NHE1 is composed of 12 transmembrane segments (TMs) with the N and C termini located in the cytosol. The large, last extracellular loop in the membrane domain of the original model was suggested to comprise an intracellular loop, a new transmembrane segment (TM11), and an extracellular loop in the new model. Interestingly, cysteines at 183 and 184 and at 324 and 325 mapped to intracellular loops connecting TMs 4 and 5 (IL2) and TMs 8 and 9 (IL4), respectively, were accessible to sulfhydryl reagents from the outside. Furthermore, exchange activities of two mutants, R180C and Q181C, within IL2 were markedly inhibited by external MTSET. These data suggest that part of IL2 or IL4 may be located in a pore-lining region that is accessible from either side of the membrane and involved in ion transport.
Collapse
|
|
25 |
168 |
3
|
Green D, Lee MY, Lim AC, Chmiel JS, Vetter M, Pang T, Chen D, Fenton L, Yarkony GM, Meyer PR. Prevention of thromboembolism after spinal cord injury using low-molecular-weight heparin. Ann Intern Med 1990; 113:571-4. [PMID: 2169216 DOI: 10.7326/0003-4819-113-8-571] [Citation(s) in RCA: 146] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
OBJECTIVE To examine the safety and effectiveness of a low-molecular-weight heparin in the prevention of thromboembolism in patients with recent spinal cord injury and complete motor paralysis. DESIGN Randomized evaluation of two heparin regimens in 41 consecutive patients meeting eligibility requirements for anticoagulant prophylaxis. Daily bedside examinations were supplemented by serial venous flow studies; suspicious or positive tests were confirmed by venography. INTERVENTION Standard heparin, 5000 units subcutaneously three times a day; low-molecular-weight heparin 3500 anti-Xa units subcutaneously once daily. MEASUREMENTS AND MAIN RESULTS Five patients in the standard heparin group had thrombotic events, including two patients with fatal pulmonary embolism; two other patients had bleeding severe enough to necessitate withdrawing the heparin. The cumulative event rate was 34.7% (95% CI, 13.7% to 55.2%). None of the patients treated with low-molecular-weight heparin had thrombosis or bleeding (CI, 0% to 14%). The difference between the two groups was significant (P = 0.006, log-rank test). CONCLUSIONS Low-molecular-weight heparin is safe and effective in the prevention of thromboembolism in selected patients with spinal cord injury and complete motor paralysis, and is superior to standard heparin in fixed doses of 5000 units three times a day.
Collapse
|
Clinical Trial |
35 |
146 |
4
|
Pang T, Su X, Wakabayashi S, Shigekawa M. Calcineurin homologous protein as an essential cofactor for Na+/H+ exchangers. J Biol Chem 2001; 276:17367-72. [PMID: 11350981 DOI: 10.1074/jbc.m100296200] [Citation(s) in RCA: 128] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Na+/H+ exchangers (NHEs) comprise a family of transporters that catalyze cell functions such as regulation of the pH and volume of a cell and epithelial absorption of Na+ and bicarbonate. Ubiquitous calcineurin B homologous protein (CHP or p22) is co-localized and co-immunoprecipitated with expressed NHE1, NHE2, or NHE3 independently of its myristoylation and Ca2+ binding, and its binding site was identified as the juxtamembrane region within the carboxyl-terminal cytoplasmic domain of exchangers. CHP binding-defective mutations of NHE1-3 or CHP depletion by injection of the competitive CHP-binding region of NHE1 into Xenopus oocytes resulted in a dramatic reduction (>90%) in the Na+/H+ exchange activity. The data suggest that CHP serves as an essential cofactor, which supports the physiological activity of NHE family members.
Collapse
|
Research Support, Non-U.S. Gov't |
24 |
128 |
5
|
Pang T, Bhutta ZA, Finlay BB, Altwegg M. Typhoid fever and other salmonellosis: a continuing challenge. Trends Microbiol 1995; 3:253-5. [PMID: 7551636 DOI: 10.1016/s0966-842x(00)88937-4] [Citation(s) in RCA: 113] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
|
|
30 |
113 |
6
|
Smulson ME, Simbulan-Rosenthal CM, Boulares AH, Yakovlev A, Stoica B, Iyer S, Luo R, Haddad B, Wang ZQ, Pang T, Jung M, Dritschilo A, Rosenthal DS. Roles of poly(ADP-ribosyl)ation and PARP in apoptosis, DNA repair, genomic stability and functions of p53 and E2F-1. ADVANCES IN ENZYME REGULATION 2000; 40:183-215. [PMID: 10828352 DOI: 10.1016/s0065-2571(99)00024-2] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
Review |
25 |
96 |
7
|
Thong KL, Cheong YM, Puthucheary S, Koh CL, Pang T. Epidemiologic analysis of sporadic Salmonella typhi isolates and those from outbreaks by pulsed-field gel electrophoresis. J Clin Microbiol 1994; 32:1135-41. [PMID: 7914202 PMCID: PMC263623 DOI: 10.1128/jcm.32.5.1135-1141.1994] [Citation(s) in RCA: 95] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Pulsed-field gel electrophoresis (PFGE) was used to compare and analyze 158 isolates of Salmonella typhi from five well-defined outbreaks of typhoid fever in Malaysia and also isolates involved in sporadic cases of typhoid fever occurring during the same period. Digestion of chromosomal DNAs from these S. typhi isolates with the restriction endonucleases XbaI (5'-TCTAGA-3'), SpeI (5'-ACTAGT-3'), and AvrII (5'-CCTAGG-3') and then PFGE produced restriction endonuclease analysis (REA) patterns consisting of 11 to 24 DNA fragments ranging in size from 20 to 630 kbp. Analysis of the REA patterns generated by PFGE after digestion with XbaI and SpeI indicated that the S. typhi isolates obtained from sporadic cases of infection were much more heterogeneous (at least 13 different REA patterns were detected; Dice coefficient, between 0.73 and 1.0) than those obtained during outbreaks of typhoid fever. The clonal nature and the close genetic identities of isolates from outbreaks in Alor Setar, Penang, Kota Kinabalu, Johor Bahru, and Kota Bahru were suggested by the fact that only a limited number of REA patterns, which mostly differed by only a single band, were detected (one to four patterns; Dice coefficient, between 0.82 and 1.0), although a different pattern was associated with each of these outbreaks. Comparison of REA patterns with ribotyping for 18 S. typhi isolates involved in sporadic cases of infection showed a good correlation, in that 72% of the isolates were in the same group. There was no clear correlation of phage types with a specific REA pattern. We conclude that PFGE of s. typhi chromosomal DNA digested with infrequently cutting restriction endonucleases is a useful method for comparing and differentiating S. typhi isolates for epidemiological purposes.
Collapse
|
research-article |
31 |
95 |
8
|
Thong KL, Ngeow YF, Altwegg M, Navaratnam P, Pang T. Molecular analysis of Salmonella enteritidis by pulsed-field gel electrophoresis and ribotyping. J Clin Microbiol 1995; 33:1070-4. [PMID: 7615707 PMCID: PMC228106 DOI: 10.1128/jcm.33.5.1070-1074.1995] [Citation(s) in RCA: 83] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
A total of 61 isolates of Salmonella enteritidis were analyzed by the techniques of pulsed-field gel electrophoresis (PFGE) and ribotyping. Twenty-three of the isolates were from Zurich, Switzerland, and 38 isolates were from the University Hospital, Kuala Lumpur, Malaysia. Five of the Malaysian isolates were hospital-related outbreak strains and were shown to be indistinguishable by PFGE analysis following digestion with three different restriction endonucleases, XbaI (5'-TCTAGA-3'), SpeI (5'-ACTAGT-3'), and AvrII (5'-CCTAGG-3'). The PFGE pattern of an isolate from a suspected carrier staff nurse was found to be identical to those of the hospital outbreak isolates. These isolates were also indistinguishable by ribotyping with SmaI and SphI. The same single PFGE pattern was also detected in 29 of 32 sporadic isolates of S. enteritidis. Four closely related ribotypes were detected among these 29 isolates. Similarly, outbreak-related strains from Switzerland showed close genetic identity by PFGE and ribotyping. Strains obtained from poultry showed more variations in their PFGE patterns and ribotypes, although the patterns were still closely related. In addition, SphI ribotypes A and D among the Swiss strains correlated with phage types 4 and 8, respectively. No correlation of phage types with PFGE pattern was noted. Both PFGE and ribotyping indicate that the S. enteritidis strains circulating in Malaysia and Switzerland are very similar and may be clonally related. Comparison of the PFGE patterns with the ribotypes for 23 Swiss and 16 Malaysian isolates showed that there was a 69% concordance in the grouping of isolates. We conclude that the close genetic similarity observed between epidemiologically unrelated and outbreak-related isolates of S. enteritidis suggests that both PFGE and ribotyping are of limited value in the epidemiological analysis of these particular isolates, possibly because of the highly clonal nature of pathogenic strains of S. enteritidis.
Collapse
|
research-article |
30 |
83 |
9
|
Pang T, Levine MM, Ivanoff B, Wain J, Finlay BB. Typhoid fever--important issues still remain. Trends Microbiol 1998; 6:131-3. [PMID: 9587187 DOI: 10.1016/s0966-842x(98)01236-0] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
|
|
27 |
75 |
10
|
Roth EJ, Park T, Pang T, Yarkony GM, Lee MY. Traumatic cervical Brown-Sequard and Brown-Sequard-plus syndromes: the spectrum of presentations and outcomes. PARAPLEGIA 1991; 29:582-9. [PMID: 1787982 DOI: 10.1038/sc.1991.86] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Brown-Sequard syndrome (BSS) and Brown-Sequard-plus syndrome (BSPS) are characterised by asymmetrical paresis with hypalgesia more marked on the less paretic side. This study examined the clinical features of 38 patients (30 males and 8 females; mean age = 32 years) with traumatic cervical BSS or BSPS who underwent comprehensive inpatient rehabilitation. Twenty two injuries were caused by road traffic accidents, 8 by penetrating injuries, 5 by diving injuries, and 3 by other causes. After an average of 35 days in acute care and 79 days in rehabilitation, 37 patients had increased muscle strength, all 38 patients improved functional abilities, 29 patients walked independently, 34 had spontaneous bladder emptying, 36 were discharged home, and 14 were employed. Statistically significant increases (p less than 0.001) were made in modified Barthel index functional scores between admission and discharge. Patients with BSPS had a better prognosis than did those with 'pure' BSS. Patients with predominant upper limb weakness had more favourable outcomes than did those with predominant lower limb weakness. Few other potentially predictive demographic, injury, or neurological factors were associated with functional outcome. Patients with BSS or BSPS generally have a good prognosis for neurological and functional improvement.
Collapse
|
Comparative Study |
34 |
63 |
11
|
Thong KL, Puthucheary S, Yassin RM, Sudarmono P, Padmidewi M, Soewandojo E, Handojo I, Sarasombath S, Pang T. Analysis of Salmonella typhi isolates from Southeast Asia by pulsed-field gel electrophoresis. J Clin Microbiol 1995; 33:1938-41. [PMID: 7665677 PMCID: PMC228306 DOI: 10.1128/jcm.33.7.1938-1941.1995] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Pulsed-field gel electrophoresis (PFGE) revealed that multiple genetic variants of Salmonella typhi are simultaneously present in Southeast Asia and are associated with sporadic cases of typhoid fever and occasional outbreaks. Comparative analysis of PFGE patterns also suggested that considerable genetic diversity exists among S. typhi strains and that some PFGE patterns are shared between isolates obtained from Malaysia, Indonesia, and Thailand, implying movement of these strains within these regions of Southeast Asia, where they are endemic.
Collapse
|
research-article |
30 |
56 |
12
|
Pang T, Stalberg P, Sidhu S, Sywak M, Wilkinson M, Reeve TS, Delbridge L. Minimally invasive parathyroidectomy using the lateral focused mini-incision technique without intraoperative parathyroid hormone monitoring. Br J Surg 2007; 94:315-9. [PMID: 17205496 DOI: 10.1002/bjs.5608] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
BACKGROUND Minimally invasive parathyroidectomy (MIP) involves scan-directed removal of a single adenoma through a 2.0-cm mini-incision without intraoperative monitoring. The aim of this study was to analyse the outcomes of MIP using such a simplified technique. METHODS The study group comprised 500 consecutive patients undergoing MIP via a lateral mini-incision from August 2000 to September 2005. Levels of parathyroid hormone (PTH) were measured after operation solely to aid informed discharge. RESULTS Some 97.4 per cent of patients were initially cured by MIP. Eight patients remained hypercalcaemic and a further five were normocalcaemic on the day after surgery but became hypercalcaemic again within 3 months of the procedure. Eleven of these patients were cured with subsequent re-exploration. Analysis of postoperative PTH data indicated that, at best, the use of intraoperative PTH measurement during surgery would have increased the cure rate by only a further 1 per cent. Three (0.6 per cent) of 500 patients had permanent recurrent laryngeal nerve palsy after MIP. CONCLUSION MIP performed by the lateral focused mini-incision technique, without the use of intraoperative PTH monitoring, is a safe and effective procedure that results in outcomes equal to those of bilateral neck exploration.
Collapse
|
Journal Article |
18 |
51 |
13
|
Kietzmann H, Morenzin J, Bechthold PS, Ganteför G, Eberhardt W, Yang DS, Hackett PA, Fournier R, Pang T, Chen C. Photoelectron Spectra and Geometric Structures of Small Niobium Cluster Anions. PHYSICAL REVIEW LETTERS 1996; 77:4528-4531. [PMID: 10062561 DOI: 10.1103/physrevlett.77.4528] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
|
|
29 |
48 |
14
|
Pang T, Puthucheary SD. Significance and value of the Widal test in the diagnosis of typhoid fever in an endemic area. J Clin Pathol 1983; 36:471-5. [PMID: 6833514 PMCID: PMC498248 DOI: 10.1136/jcp.36.4.471] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The diagnostic value of the Widal test was assessed in an endemic area. The test was done on 300 normal individuals, 297 non-typhoidal fevers and 275 bacteriologically proven cases of typhoid. Of 300 normal individuals, 2% had an H agglutinin titre of 1/160 and 5% had an O agglutinin titre of 1/160. On the basis of these criteria a significant H and/or O agglutinin titre of 1/320 or more was observed in 93-97% of typhoid cases and in only 3% of patients with non-typhoidal fever. Of the sera from typhoid cases which gave a significant Widal reaction, the majority (79.9%) showed increases in both H and O agglutinins and 51 of 234 (21.8%) of these sera were collected in the first week of illness. The significance and implications of these findings are discussed.
Collapse
|
research-article |
42 |
44 |
15
|
Pang T, McKenzie IF, Blanden RV. Cooperation between mouse T-cell subpopulations in the cell-mediated response to a natural poxvirus pathogen. Cell Immunol 1976; 26:153-9. [PMID: 61822 DOI: 10.1016/0008-8749(76)90359-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
|
49 |
44 |
16
|
Abstract
A 48-hour culture filtrate of Campylobacter jejuni was found to produce cytopathic effects on three human cell lines--that is, HeLa, MRC-5 and Hep-2. The cytopathic effects observed include cell rounding, loss of adherence and cell death after 24-48 h of incubation. Such morphological changes were observed with eight of the eleven strains of Campylobacter jejuni isolated from the blood/stools of patients who suffered from either acute gastroenteritis or septicaemia. The toxic factor did not retain its activity after treatment at 100 degrees C for 30 min. Trypsinisation of the filtrate totally abolished its toxic activity thus indicating that it was probably protein in nature. It is most probably an extracellular toxin as bacterial sonicates did not produce any toxic effect. This study reports the finding of toxic factor(s) in the culture filtrate of Campylobacter jejuni which is cytotoxic to human tissue culture cells.
Collapse
|
research-article |
42 |
42 |
17
|
Thong KL, Passey M, Clegg A, Combs BG, Yassin RM, Pang T. Molecular analysis of isolates of Salmonella typhi obtained from patients with fatal and nonfatal typhoid fever. J Clin Microbiol 1996; 34:1029-33. [PMID: 8815078 PMCID: PMC228948 DOI: 10.1128/jcm.34.4.1029-1033.1996] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Molecular characterization of a total of 52 human isolates of Salmonella typhi from Papua New Guinea was performed by using pulsed-field gel electrophoresis (PFGE) after digestion of chromosomal DNA with three restriction endonucleases, XbaI (5'-TCTAGA-3'), AvrII (5'-CCTAGG-3'), and SpeI (5'-ACTAGT-3'). Of the 52 isolates tested, 11 were obtained from patients with fatal typhoid fever and 41 were obtained from patients with nonfatal disease. The 52 isolates showed limited genetic diversity as evidenced by only three different PFGE patterns detected following digestion with XbaI (patterns X1 to X3; F [coefficient of similarity] = 0.86 to 1.0), four patterns detected following digestion with AvrII (patterns A1 to A4; F =0.78 to 1.0), and two patterns detected following digestion with SpeI (patterns S1 and S2; F = 0.97 to 1.0). Of the 52 isolates, 37 were phage typed, and all belonged to phage type D2. All 11 isolates obtained from patients with fatal typhoid fever were identical (F = 1.0) and possessed the PFGE pattern combination X1S1A1, whereas the 41 isolates from patients with nonfatal typhoid fever had various PFGE pattern combinations, the most common being X2S1A2 (39%), X1S1A1 (24%), and X1S1A2 (15%). Thus, all the isolates from patients with the fatal disease had the X1 and A1 patterns, whereas the majority of the isolates from patients with nonfatal typhoid fever possessed the X2 and A2 patterns. The data suggest that there is an association among strains of S. typhi between genotype, as assessed by PFGE patterns, and the capability to cause fatal illness. Analysis of blood and fecal isolates of S. typhi from the same patient also indicated that some genetic changes occur in vivo during the course of infection.
Collapse
|
research-article |
29 |
39 |
18
|
Nair S, Schreiber E, Thong KL, Pang T, Altwegg M. Genotypic characterization of Salmonella typhi by amplified fragment length polymorphism fingerprinting provides increased discrimination as compared to pulsed-field gel electrophoresis and ribotyping. J Microbiol Methods 2000; 41:35-43. [PMID: 10856775 DOI: 10.1016/s0167-7012(00)00148-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Amplified fragment length polymorphism (AFLP) is a recently developed, PCR-based high resolution fingerprinting method that is able to generate complex banding patterns which can be used to delineate intraspecific genetic relationships among bacteria. In the present study, AFLP was evaluated for its usefulness in the molecular typing of Salmonella typhi in comparison to ribotyping and pulsed-field gel electrophoresis (PFGE). Six S. typhi isolates from diverse geographic areas (Malaysia, Indonesia, India, Chile, Papua New Guinea and Switzerland) gave unique, heterogeneous profiles when typed by AFLP, a result which was consistent with ribotyping and PFGE analysis. In a further study of selected S. typhi isolates from Papua New Guinea which caused fatal and non-fatal disease previously shown to be clonally related by PFGE, AFLP discriminated between these isolates but did not indicate a linkage between genotype with virulence. We conclude that AFLP (discriminatory index=0.88) has a higher discriminatory power for strain differentiation among S. typhi than ribotyping (DI=0.63) and PFGE (DI=0.74).
Collapse
|
Comparative Study |
25 |
39 |
19
|
Thong KL, Cordano AM, Yassin RM, Pang T. Molecular analysis of environmental and human isolates of Salmonella typhi. Appl Environ Microbiol 1996; 62:271-4. [PMID: 8572705 PMCID: PMC167795 DOI: 10.1128/aem.62.1.271-274.1996] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Molecular characterization of a total of 54 isolates of Salmonella typhi from Santiago, Chile, was performed by pulsed-field gel electrophoresis (PFGE) after digestion of chromosomal DNA with three restriction endonucleases: XbaI (5'-TCTAGA-3'), AvrII (5'-CCTAGG-3'), and SpeI (5'-ACTAGT-3'). Thirteen of the 54 isolates were obtained from environmental sources (sewage and river water), and the rest were isolates from clinical cases of typhoid fever. Considerable genetic diversity was detected among the human isolates obtained in 1994, as evidenced by the presence of 14 to 19 different PFGE patterns among 20 human isolates, with F (coefficient of similarity) values ranging from 0.69 to 1.0 (XbaI), 0.61 to 1.0 (AvrII), and 0.70 to 1.0 (SpeI). A total of eight phage types were detected among these 20 isolates, with 50% possessing the E1 or 46 phage type. There was no correlation between PFGE pattern and phage types. Similar diversity was seen among 21 isolates obtained in 1983, with 17 to 19 PFGE patterns detected and F values of 0.56 to 1.0 (XbaI), 0.55 to 1.0 (AvrII), and 0.67 to 1.0 (SpeI). Comparison of these two groups of human isolates obtained 11 years apart indicated that certain molecular types of S. typhi are shared and are able to persist for considerable periods. A similar degree of genetic diversity was also detected among the environmental isolates of S. typhi, for which 10 to 12 different PFGE patterns were detected among the 13 isolates analyzed, with F values ranging from 0.56 to 1.0 (XbaI), 0.52 to 1.0 (AvrII), and 0.69 to 1.0 (SpeI). Certain molecular types present among the environmental isolates of S. typhi were also found among the human isolates from the same time period, providing evidence for the epidemiological link between environmental reservoirs and human infection.
Collapse
|
research-article |
29 |
38 |
20
|
Mahalingam S, Cheong YM, Kan S, Yassin RM, Vadivelu J, Pang T. Molecular epidemiologic analysis of Vibrio cholerae O1 isolates by pulsed-field gel electrophoresis. J Clin Microbiol 1994; 32:2975-9. [PMID: 7883885 PMCID: PMC264210 DOI: 10.1128/jcm.32.12.2975-2979.1994] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Isolates of Vibrio cholerae O1 El Tor from two well-defined cholera outbreaks in Malaysia were analyzed by using pulsed-field gel electrophoresis (PFGE). Isolates from sporadic cases occurring during the same time period were also studied. Digestion of chromosomal DNA from these isolates of V. cholerae O1 with restriction endonucleases NotI (5'-GCGGCCGC-3') and SfiI (5'-GGCCNNNN-3'), followed by PFGE, produced restriction endonuclease analysis (REA) patterns consisting of 13 to 24 bands (ranging in size from 46 to 398 kbp). Analysis of the REA patterns generated by PFGE after digestion with NotI and SfiI suggested the clonal nature and close genetic identity of the isolates obtained during each of the two outbreaks (Dice coefficient, 0.93 to 1.0). Although they had very similar REA patterns, the two outbreak clones were not identical. Isolates of V. cholerae O1 from sporadic cases, on the other hand, appeared to be much more heterogeneous (five different REA patterns detected in the five isolates tested; Dice coefficient, 0.31 to 0.81) than those obtained during the two outbreaks. We conclude that PFGE of V. cholerae O1 chromosomal DNA digested with infrequently cutting restriction endonucleases is a useful method for molecular typing of V. cholerae isolates for epidemiological purposes.
Collapse
|
research-article |
31 |
31 |
21
|
Pang T, Louie SG. Negative-donor centers in semiconductors and quantum wells. PHYSICAL REVIEW LETTERS 1990; 65:1635-1638. [PMID: 10042320 DOI: 10.1103/physrevlett.65.1635] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
|
|
35 |
29 |
22
|
Chang G, Wang J, Zhang H, Zhang Y, Wang C, Xu H, Zhang H, Lin Y, Ma L, Li Q, Pang T. CD44 targets Na(+)/H(+) exchanger 1 to mediate MDA-MB-231 cells' metastasis via the regulation of ERK1/2. Br J Cancer 2014; 110:916-27. [PMID: 24434427 PMCID: PMC3929887 DOI: 10.1038/bjc.2013.809] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Revised: 11/24/2013] [Accepted: 12/04/2013] [Indexed: 12/31/2022] Open
Abstract
Background: CD44, a transmembrane glycoprotein expressed in a variety of cells and tissues, has been implicated in tumour metastasis. But the molecular mechanisms of CD44-mediated tumour cell metastasis remain to be elucidated. Methods: The downregulation of CD44 was determined by immunofluorescence. Moreover, the motility of breast cancer cells was detected by wound-healing and transwell experiments. Then the spontaneous metastasis of CD44-silenced MDA-MB-231 cells was tested by histology with BALB/c nude mice. Results: A positive correlation between CD44 and Na+/H+ exchanger isoform 1 (NHE1) was found in two breast cancer cells. CD44 downregulation could inhibit the metastasis of MDA-MB-231 cells and the expressions of Na+/H+ exchanger 1. Moreover, CD44 overexpression upregulated the metastasis of MCF-7 cells, but the elevated metastatic ability was then inhibited by Cariporide. Interestingly, during these processes only the p-ERK1/2 was suppressed by CD44 downregulation and the expression of matrix metalloproteinases and metastatic capacity of MDA-MB-231 cells were greatly inhibited by the MEK1 inhibitor PD98059, which even had a synergistic effect with Cariporide. Furthermore, CD44 downregulation inhibits breast tumour outgrowth and spontaneous lung metastasis. Conclusions: Taken together, this work indicates that CD44 regulates the metastasis of breast cancer cells through regulating NHE1 expression, which could be used as a novel strategy for breast cancer therapy.
Collapse
|
Research Support, Non-U.S. Gov't |
11 |
27 |
23
|
Huant S, Mandray A, Zhu J, Louie SG, Pang T, Etienne B. Well-width dependence of D- cyclotron resonance in quantum wells. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 48:2370-2375. [PMID: 10008629 DOI: 10.1103/physrevb.48.2370] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
|
32 |
24 |
24
|
Pang T, Blanden RV. Regulation of the T-cell response to ectromelia virus infection. I. Feedback suppression by effector T cells. J Exp Med 1976; 143:469-81. [PMID: 175126 PMCID: PMC2190147 DOI: 10.1084/jem.143.3.469] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Spleen cells and serum from mice immunized with ectromelia virus suppressed the immune response to infectious virus when transferred intravenously into recipient mice given an immunizing virus dose. The suppression was reflected in decreased cytotoxic T-cell activity directed against H-2 compatible virus-infected target cells in the spleens of recipients. Suppression was observed when immune cells or serum were transferred 1-2 h or 1 day after immunization of recipients, but not 2 days after, and was maximal when 6-day immune spleen cells were used as suppressor cells. H-2 compatibility between donor and recipient mice was necessary for suppression to be expressed. Use of recombinant mice showed that I-region compatibility was neither sufficient nor necessary, and that D-region compatibility was sufficient. Specificity of suppression was suggested by the finding that cells and serum from mice immunized with Listeria monocytogenes, a bacterium, had no suppressive activity on the antiviral response. Anti-theta treatment eliminated the ability of immune cells to suppress, and the suppressive effect was not markedly dose-dependent with respect to both cell dose and virus dose under the conditions employed. Virus levels in the spleens of recipients were significantly reduced after injection of immune cells. Adult thymectomy had no effect on the primary immune response to ectromelia virus infection, thus indicating no role for T1 cells in the suppressive mechanism. The results obtained therefore suggested that suppression in this system was due to effector T cells which triggered clearance of virus (and thus, of virus-induced antigens) necessary for the induction of precursors of effector T cells, and that this simple feed-back mechanism normally plays an important role in the regulation of the primary immune response to ectromelia infection at the level of precursor induction. The existence of other postinduction regulatory mechanisms, however, is unknown and under investigation.
Collapse
|
research-article |
49 |
24 |
25
|
Hou X, Chen X, Zhang P, Fan Y, Ma A, Pang T, Song Z, Jin Y, Hao W, Liu F, Wang W, Wang Y. Inhibition of hedgehog signaling by GANT58 induces apoptosis and shows synergistic antitumor activity with AKT inhibitor in acute T cell leukemia cells. Biochimie 2014; 101:50-9. [PMID: 24394624 DOI: 10.1016/j.biochi.2013.12.019] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 12/19/2013] [Indexed: 12/11/2022]
Abstract
The hedgehog (Hh) signaling pathways have a crucial role in cell proliferation and survival, and the de-regulation of these pathways can lead to tumorigenesis. Here we investigated the expression and function of these pathways in acute T lymphocytic leukemia cells (T-ALL). Profiling of Hh pathway members revealed common expression of key Hh signaling effectors in all T-ALL cells. We found that T-ALL cells were insensitive to specific Smoothened (SMO) inhibition following the use of low concentrations of the SMO antagonist cyclopamine. In contrast, treatment with the novel GLI antagonist GANT58 reduced expression of the target gene Patched 1 as well as GLI family zinc finger 1 (GLI1) and preferentially decreased the viability of T-ALL cells. We also found perifosine, a novel AKT inhibitor, down-regulated GLI1 protein by dephosphorylation of AKT and GSK3β dose-dependently and that pre-treatment with PD98059, a MEK/ERK pathway inhibitor, enhanced this down-regulation by 20%-30%. Then we questioned whether use of both GANT58 and AKT inhibitor together could confer a synergistic effect to decrease T-ALL cell viability. By applying the Chou-Talalay method, low concentration of GANT58 induced T-ALL cell death in a synergism fashion with perifosine or GSK690693 when used simultaneously. These findings indicate that the combined use of GANT58 and AKT inhibitor could help treat a broad range of malignant tumors in conjunction with existing cancer treatments.
Collapse
|
Research Support, Non-U.S. Gov't |
11 |
24 |