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Garcia-Closas M, Hankinson SE, Ho S, Malins DC, Polissar NL, Schaefer SN, Su Y, Vinson MA. Factors critical to the design and execution of epidemiologic studies and description of an innovative technology to follow the progression from normal to cancer tissue. J Natl Cancer Inst Monogr 2001:147-56. [PMID: 10963626 DOI: 10.1093/oxfordjournals.jncimonographs.a024238] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The results obtained from experimental studies of estrogen carcinogenesis need validation in epidemiologic studies. Such studies present additional challenges, however, because variations in human populations are much greater than those in experimental systems and in animal models. Because epidemiologic studies are often used to evaluate modest differences in risk factors, it is essential to minimize sources of errors and to maximize sensitivity, reproducibility, and specificity. In the first part of this chapter, critical factors in designing and executing epidemiologic studies, as well as the influence of sample collection, processing, and storage on data reliability, are discussed. One of the most important requirements is attaining sufficient statistical power to assess small genetic effects and to evaluate interactions between genetic and environmental factors. The second part of this chapter describes innovative technology, namely, Fourier transform-infrared (FT-IR) spectra of DNA that reveal major structural differences at various stages of the progression from normal to cancer tissue. The structural differences become evident from wavenumber-by-wavenumber statistical comparisons of the mean FT-IR spectra of DNA from normal to cancer tissues. This analysis has allowed distinguishing benign tissues from cancer and metastatic tissues in human breast, prostate, and ovarian cancers. This analysis, which requires less than 1 microg of DNA, is predicted to be used for detecting early cancer-related changes at the level of DNA, rather than at the cellular level.
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Ho S, Chao Y, Tong W, Yu S. Sugar coordinately and differentially regulates growth- and stress-related gene expression via a complex signal transduction network and multiple control mechanisms. PLANT PHYSIOLOGY 2001; 125:877-90. [PMID: 11161045 PMCID: PMC64889 DOI: 10.1104/pp.125.2.877] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2000] [Revised: 08/25/2000] [Accepted: 10/07/2000] [Indexed: 05/18/2023]
Abstract
In plants, sugars are required to sustain growth and regulate gene expression. A large set of genes are either up- or down-regulated by sugars; however, whether there is a common mechanism and signal transduction pathway for differential and coordinated sugar regulation remain unclear. In the present study, the rice (Oryza sativa cv Tainan 5) cell culture was used as a model system to address this question. Sucrose and glucose both played dual functions in gene regulation as exemplified by the up-regulation of growth-related genes and down-regulation of stress-related genes. Sugar coordinately but differentially activated or repressed gene expression, and nuclear run-on transcription and mRNA half-life analyses revealed regulation of both the transcription rate and mRNA stability. Although coordinately regulated by sugars, these growth- and stress-related genes were up-regulated or down-regulated through hexokinase-dependent and/or hexokinase-independent pathways. We also found that the sugar signal transduction pathway may overlap the glycolytic pathway for gene repression. alpha-Amylase and the stress-related genes identified in this study were coordinately expressed under sugar starvation, suggesting a convergence of the nutritional and environmental stress signal transduction pathways. Together, our studies provide a new insight into the complex signal transduction network and mechanisms of sugar regulation of growth and stress-related genes in plants.
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Francès V, Guret C, Malisan F, Peyron E, Ho S, Maat MJ, Fossiez F, Nicolas JF, Lebecque S, Martinez-Valdez H. The human anti-bullous pemphigoid monoclonal autoantibody P22 is encoded by genes of the IGHV4 and IGLV4 families. J Autoimmun 2000; 15:459-68. [PMID: 11090245 DOI: 10.1006/jaut.2000.0445] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We identified, cloned, and biochemically characterized the full-length cDNAs encoding the heavy and light chains of a human monoclonal antibody (mAb) from the Epstein-Barr virus (EBV)-cell line P22. The cell line P22, which originated from a patient with bullous pemphigoid (an autoimmune disease causing skin blistering) expressed immunoglobulin-G (IgG) with a lambda light chain. Although the variable heavy (IGHV) chain gene family could not be assigned by IGHV repertoire analysis, the determination of its nucleotide sequence demonstrated that the heavy chain of P22 belonged to the IGHV4 family. The limited IGHV4 gene usage by memory IgG, IGA and IgE-expressing cells supports the notion of the autoreactivity-associated IGHV4 genes and stresses the strong selection pressure within germinal centres towards IGHV4 family. Alignment of P22 IGHV4 cDNA sequence to germline sequences from gene databases, revealed a remarkable divergence, suggesting that the heavy chain of the P22 mAb encodes a distinct IGHV4 gene. The variable light chain (IGLV) encodes a IGLV4 gene and is 98% similar to a previously reported IGLV gene. Furthermore, fluorescent staining with the recombinant mAb showed the same reactivity to that of the native antibody. The data reported herein, (a) reveal an autoantibody encoding a distinct IGHV4 gene, (b) confirm the notion that autoantibodies preferentially use IGHV4 genes, and (c) hypothesize that somatic hypermutation within GC may be a mechanism by which autoreactive B lymphocytes escape negative selection.
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Hsu AT, Ho L, Ho S, Hedman T. Immediate response of glenohumeral abduction range of motion to a caudally directed translational mobilization: a fresh cadaver simulation. Arch Phys Med Rehabil 2000; 81:1511-6. [PMID: 11083357 DOI: 10.1053/apmr.2000.9389] [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: 11/11/2022]
Abstract
OBJECTIVE To investigate the immediate effect of caudal glide translational mobilization on the range of motion (ROM) of passive glenohumeral abduction with a fresh cadaver model to simulate the mobilization movement performed by a physical therapist treating patients with glenohumeral hypomobility. DESIGN Mechanical simulation of caudal glide mobilization and abduction torque range of motion (TROM) measurement of the glenohumeral joint with 2 material testing systems. Mobilizations were conducted with the glenohumeral joint positioned at a resting position (IGR) and at the end range of abduction (IGE). SETTING Biomechanics laboratory. CADAVERS Twenty fresh shoulder specimens from 10 cadavers (mean age, 68 +/- 8 yr). MAIN OUTCOME MEASURE Changes in TROM of the glenohumeral abduction in response to 5 bouts of caudal glide mobilization. RESULTS At least 3 repetitions of TROM were required to attain consistent measurements on glenohumeral abduction ROM. Significant differences were found among changes in TROM because of rest, IGR, and IGE (Kruskal-Wallis statistics, (chi2 = 14.58, p = .001). A greater increase in glenohumeral abduction TROM was found after IGE (mean +/- standard error of the mean, 4.38 degrees +/- 0.95 degrees) compared with the rest control (0.03 degrees +/- 0.07 degrees; Mann-Whitney test, p = .001, alpha = .017) or its IGR counterpart (0.26 degrees +/- 0.46 degrees, p = .001, alpha = .017). CONCLUSION This simulation of caudal glide translational mobilization at the end range using cadaver models improved passive glenohumeral abduction ROM but was ineffective when performed with the shoulder placed in a resting position. The mechanical responses of the glenohumeral joint to translational mobilization in a live patient may be similar, but some caution should be used in generalizing these findings.
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Leung SK, Lau CP, Lam CT, Ho S, Tse HF, Yu CM, Lee K, Tang MO, To KM, Renesto F. Automatic optimization of resting and exercise atrioventricular interval using a peak endocardial acceleration sensor: validation with Doppler echocardiography and direct cardiac output measurements. Pacing Clin Electrophysiol 2000; 23:1762-6. [PMID: 11139919 DOI: 10.1111/j.1540-8159.2000.tb07014.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Peak endocardial acceleration (PEA) measured by an implantable acceleration sensor inside the tip of a pacing lead reflects ventricular filling and myocardial contractility. The contribution of the plateau phase of PEA as an indicator of optimal ventricular filling, hence of the appropriate atrioventricular interval (AVI) at rest and during exercise, was studied in 12 patients (age 69 +/- 6 years) with complete AV block and a PEA sensing DDDR pacemakers (Living 1 Plus, Sorin Biomedica). At a mean resting heart rate of 79 +/- 15 beats/min, the mean AVI optimized by PEA versus Doppler echocardiography (echo) were identical (142 +/- 37 vs 146 +/- 26 ms, P = 0.59). During submaximal exercise at a mean heart rate of 134 +/- 6 beats/min, AVI optimized by PEA was 135 +/- 37 ms. Cardiac output at rest, measured by the CO2 rebreathing method, was comparable with AVI determined by echo versus PEA (4.3 +/- 2.9 and 3.7 +/- 2.4 L/min, respectively), and increased to the same extent (8.0 +/- 3.9 vs 8.3 +/- 5.2 L/min) during submaximal exercise. In patients with AV block, AVI automatically set by PEA was comparable with AVI manually optimized by Doppler echocardiography and was associated with comparable exercise induced hemodynamic changes.
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Abstract
OBJECTIVE This study compared the risk of ischemic heart disease among older vegetarian Chinese women with that of older non-vegetarian women. METHODS 90 vegetarian Chinese women over 70 years old in Hong Kong were screened for ischemic heart disease by electrocardiogram (ECG) and cardiovascular questionnaire. They were compared with 90 non-vegetarian women of similar age examined in a previous local survey. The effects of confounding factors were adjusted by stepwise logistic regression analysis. RESULTS The percentages of subjects with ischemic heart disease defined by symptoms and ECG or by ECG alone were significantly lower in vegetarian women (p <0.005 and p<0.05 respectively). Vegetarians had lower serum cholesterol levels: more were old age home residents and were less likely to perform regular exercise. On stepwise logistic regression, using probable ischemic heart disease defined by questionnaire and ECG as outcome measure, vegetarianism was the only significant predictor (OR 0.3, 95%CI 0.1-0.6, p<0.005). CONCLUSIONS Vegetarian older Chinese women had lower risk of ischemic heart disease when compared with non-vegetarians. Apart from lower serum cholesterol levels, vegetarianism may have other protective factors against ischemic heart disease.
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Mann DV, Edwards R, Ho S, Lau WY, Glazer G. Elevated tumour marker CA19-9: clinical interpretation and influence of obstructive jaundice. EUROPEAN JOURNAL OF SURGICAL ONCOLOGY 2000; 26:474-9. [PMID: 11016469 DOI: 10.1053/ejso.1999.0925] [Citation(s) in RCA: 199] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
AIMS The tumour marker CA19-9 has been promoted as a reliable test for the detection of pancreatobiliary malignancy, yet its diagnostic role remains poorly defined. In this study the clinical interpretation of a raised serum CA19-9 level has been evaluated, with particular reference to obstructive jaundice. METHODS One hundred and sixty-four patients with a CA19-9 level above 33 U/ml were studied. Serum CA19-9 was compared with clinical diagnosis and correlated with serum bilirubin level. In a subgroup of jaundiced patients (16 benign and 15 malignant cases), follow-up CA19-9 levels were determined 2 weeks after biliary drainage. RESULTS The median CA19-9 level was lower in benign cases (102 (IQR 50-264) U/ml) than those with pancreatobiliary tumours (910 (IQR 263-6170) U/ml; P<0.01), although the overlap was substantial. In benign jaundiced cases, a positive correlation was observed between bilirubin and CA19-9 elevation (R=0.41, P<0.01). Relief of jaundice was associated with a fall in CA19-9 level in all benign cases and in nine of the 15 with malignancy. CONCLUSION Confident discrimination between benign and malignant disease could not be made on the basis of a solitary elevated CA19-9 measurement. Hyperbilirubinaemia was associated with a further deterioration in specificity and caution is warranted when interpreting the results in jaundiced patients. Overall, only one half of patients with an elevated CA19-9 level ultimately proved to harbour a malignancy.
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Sherwood AL, Davis WC, Ho S, Macher BA, Stroud MR, Upchurch DA, Holmes EH. A GDP-fucose-protected, pyridoxal-5'-Phosphate/NaBH(4)-sensitive lys residue common to human alpha1-->3Fucosyltransferases corresponds to Lys(300) in FucT-IV. Biochem Biophys Res Commun 2000; 273:870-6. [PMID: 10891339 DOI: 10.1006/bbrc.2000.3018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Human alpha1-->3/4fucosyltransferases (FucTs) contain a common essential pyridoxal-5'-phosphate(PLP)/NaBH(4) reactive, GDP-fucose-protectable Lys. For identification, site-directed mutants at lysines of FucT-IV and -VII were prepared and tested. Non conserved lysine mutants K119Y and K394Q were similar to wild-type FucT-IV. However, mutants of conserved lysines K228R and K300R were distinct. The specific activity of K228R was 2- to 3-fold lower but retained K(m) values for donor and acceptor substrates as wild-type FucT-IV. The specific activity of K300R was reduced over 400-fold with an apparent K(m) for GDP-fucose over 200 microM. FucT-VII mutants K169R and K240R (equivalent to K228R and K300R for FucT-IV, respectively) were inactive. No change in PLP/NaBH(4) sensitivity occurred with K119Y, K228R, and K394Q compared to wild-type FucT-IV. These and previous results (A. L. Sherwood, A. T. Nguyen, J. M. Whitaker, B. A. Macher, M. R. Stroud, and E. H. Holmes, J. Biol. Chem. 273, 25256-25260, 1998) demonstrate that of three conserved lysines in FucT-IV, two (Lys(228) and Lys(283)) are not involved in substrate binding but perhaps in catalysis. The third site, Lys(300), is involved in GDP-fucose binding and PLP/NaBH(4) inactivation.
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Ho S, Lee D, Bluestone C. Imaging quiz case 2. First branchial cleft cyst (FBCC). ARCHIVES OF OTOLARYNGOLOGY--HEAD & NECK SURGERY 2000; 126:793, 796-7. [PMID: 10864121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
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Ramers C, Billman G, Hartin M, Ho S, Sawyer MH. Impact of a diagnostic cerebrospinal fluid enterovirus polymerase chain reaction test on patient management. JAMA 2000; 283:2680-5. [PMID: 10819951 DOI: 10.1001/jama.283.20.2680] [Citation(s) in RCA: 189] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
CONTEXT Enterovirus (EV) infection, the most common cause of aseptic meningitis, can be rapidly diagnosed with an EV-specific reverse transcriptase polymerase chain reaction (EV-PCR) test. However, no studies have examined EV-PCR in a clinical context in which it is routinely used. OBJECTIVE To determine the impact of EV-PCR testing on diagnosis and clinical management of suspected aseptic meningitis cases. DESIGN AND SETTING Retrospective review of electronic medical records from a 220-bed tertiary care pediatric medical center in San Diego, Calif. PATIENTS A total of 276 pediatric patients for whom a diagnostic EV-PCR test was performed during the calendar year 1998. MAIN OUTCOME MEASURES Clinical parameters such as length of stay, medication use, and ancillary test use. RESULTS One hundred thirty-seven patients (49.6%) had a positive cerebrospinal fluid EV-PCR result. Enterovirus-positive patients with results available before hospital discharge (n=95) had significantly fewer ancillary tests performed (26% vs 72% with at least 1 test performed; P<.001), received intravenous antibiotics for less time (median, 2.0 vs 3.5 days; P<.001), and had shorter hospital stays (median, 42 vs 71.5 hours; P<.001) than EV-negative patients (n=92). A positive EV-PCR result was associated with more rapid hospital discharge (median EV-PCR-to-discharge time, 5.2 hours) compared with a negative result (median EV-PCR-to-discharge time, 27.4 hours; P<.001). CONCLUSIONS Our results suggest that a positive EV-PCR result may affect clinical decision making and can promote rapid discharge of patients, and that unnecessary diagnostic and therapeutic interventions can be reduced by use of EV-PCR testing. JAMA. 2000;283:2680-2685.
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Hsu AT, Ho L, Ho S, Hedman T. Joint position during anterior-posterior glide mobilization: its effect on glenohumeral abduction range of motion. Arch Phys Med Rehabil 2000; 81:210-4. [PMID: 10668777 DOI: 10.1016/s0003-9993(00)90143-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To investigate the effect of joint position during an anterior-posterior glide (APG) procedure on the range of motion (ROM) of glenohumeral abduction in cadaver specimens. DESIGN Mechanical simulation of APG mobilization and abduction torque ROM measurement of the glenohumeral joint with a material testing system. The immediate mechanical efficacy of APG was compared in two groups of specimens at two different joint positions: midrange (n = 5) and end range (n = 6) of glenohumeral abduction. SETTING Biomechanics laboratory. SPECIMENS Eleven fresh cadaver shoulder specimens (mean age, 66.9+/-2.5 yrs). MAIN OUTCOME MEASURE Improvement in glenohumeral abduction torque ROM obtained before and after APG procedure. RESULTS Glenohumeral abduction improved significantly, as indicated by a significant increase (Kruskal-Wallis statistics, chi2 = 7.50, p = .006) in the torque ROM of the end range group (mean +/- standard error of the mean, 2.02 degrees +/- .20 degrees) over the midrange group (.64 degrees +/- .08 degrees). A significant difference in the magnitude of peak displacement of the humeral head between midrange (14.44+/-3.56 mm) and end range (3.19+/-.81 mm) groups was also found (Mann-Whitney test, p < .030). CONCLUSION This study demonstrated that APG technique performed at close to the end of the range of abduction is more effective in improving glenohumeral abduction ROM than that performed at the middle of the range of abduction.
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Ho S, Lau WY, Leung WT. In vitro assessment of Lipiodol-targeted radiotherapy for liver and colorectal cancer cell lines. Br J Cancer 2000; 82:497-8. [PMID: 10646912 PMCID: PMC2363265 DOI: 10.1054/bjoc.1999.0950] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Lin J, Ho S, Shekels L, Paparella MM, Kim Y. Mucin gene expression in the rat middle ear: an improved method for RNA harvest. Ann Otol Rhinol Laryngol 1999; 108:762-8. [PMID: 10453784 DOI: 10.1177/000348949910800809] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Mucins are heavily glycosylated proteins characterized by high molecular weight and heterogeneous structure. Mucin genes are expressed in a tissue- or epithelium-specific manner. Although mucins are known to be important structural components of the mucociliary transport system that protects epithelium against invading microorganisms, very little is known about mucin gene expression unique to the middle ear. This study demonstrated that middle ear messenger RNA specifically hybridized with rat MUC2 and human MUC2 (SMUC-41) complementary DNA probes. MUC3 and MUC5AC mucin genes, dominantly expressed in rodent intestine and trachea, were not detected in the rat middle ears in this study. The middle ear MUC2 messenger RNA harvested by lavage was characterized by a single transcript--unlike its counterpart in intestine and airways, which is characterized by polydispersity--suggestive of a better method for RNA analysis. It was concluded that rat middle ears possess a MUC2 mucin gene or homologue of human MUC2 (SMUC-41).
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Yeo W, Chan KK, Mukwaya G, Ross M, Leung WT, Ho S, Chan AT, Johnson PJ. Phase II studies with DaunoXome in patients with nonresectable hepatocellular carcinoma: clinical and pharmacokinetic outcomes. Cancer Chemother Pharmacol 1999; 44:124-30. [PMID: 10412946 DOI: 10.1007/s002800050956] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A total of 14 Chinese patients with inoperable hepatocellular carcinoma received a liposomal formulation of daunorubicin (DaunoXome) at a dose equivalent to 100 mg/m2 of the free drug every 3 weeks. Altogether, 12 patients were assessable for response; 2 patients had stable disease for 8 weeks, but all eventually developed progressive disease and there was no responder. The drug was well tolerated, with no evidence of cardiac toxicity being observed. Deterioration of liver-function tests was attributed to progressive tumors in the terminal stage of the disease. Pharmacokinetics studies revealed a biexponential decay for daunorubicin in association with mean initial and terminal half-lives of 1.8 and 7.4 h, respectively, and a mean total clearance of 15.0+/-5.5 ml/min. The AUC ratio between the metabolite daunorubicinol and daunorubicin was 0.07. These data differ markedly from the pharmacokinetics of the free drug.
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Ho S, Winkler-Lowen B, Morrish DW, Dakour J, Li H, Guilbert LJ. The role of Bcl-2 expression in EGF inhibition of TNF-alpha/IFN-gamma-induced villous trophoblast apoptosis. Placenta 1999; 20:423-30. [PMID: 10419807 DOI: 10.1053/plac.1999.0394] [Citation(s) in RCA: 38] [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
The inflammatory cytokines tumour necrosis factor alpha (TNF-alpha) and immune interferon gamma (IFN-gamma) stimulate villous cytotrophoblast apoptosis while epidermal growth factor (EGF) protects. We hypothesize that TNF-alpha, IFN-gamma and EGF regulate apoptosis in part by modulating cellular expression levels of the anti-death gene bcl-2. While Bcl-2 is reported to be strongly expressed in villous syncytiotrophoblasts, it is not known whether the protein is expressed in cultured villous cytotrophoblasts (CT) and, if so, whether it is functional. We show by Northern blot analysis that bcl-2 mRNA is expressed in cultured CT and by immunoblot analysis that the protein is strongly expressed in highly purified first trimester and term villous cytotrophoblasts. The expression levels of Bcl-2 protein were the same in first trimester and term cytotrophoblasts. Culture with TNF-alpha/IFN-gamma and EGF did not alter expression of either Bcl-2 protein or of the pro-apoptotic Bcl-2 family member Bak. Double label flow cytometric analysis that measured apoptosis and Bcl-2 content simultaneously showed that cells expressing low levels of Bcl-2 underwent TNF-alpha/IFN-gamma-induced apoptosis at a higher frequency than cells expressing lower levels. We conclude that Bcl-2 is expressed in cytotrophoblasts, that its expression is constitutive and that modulation of its expression levels does not mediate cytokine and growth factor regulation of apoptosis in these cells.
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Siegal FP, Kadowaki N, Shodell M, Fitzgerald-Bocarsly PA, Shah K, Ho S, Antonenko S, Liu YJ. The nature of the principal type 1 interferon-producing cells in human blood. Science 1999; 284:1835-7. [PMID: 10364556 DOI: 10.1126/science.284.5421.1835] [Citation(s) in RCA: 1650] [Impact Index Per Article: 66.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Interferons (IFNs) are the most important cytokines in antiviral immune responses. "Natural IFN-producing cells" (IPCs) in human blood express CD4 and major histocompatibility complex class II proteins, but have not been isolated and further characterized because of their rarity, rapid apoptosis, and lack of lineage markers. Purified IPCs are here shown to be the CD4(+)CD11c- type 2 dendritic cell precursors (pDC2s), which produce 200 to 1000 times more IFN than other blood cells after microbial challenge. pDC2s are thus an effector cell type of the immune system, critical for antiviral and antitumor immune responses.
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Draganich LF, Hsieh YF, Ho S, Reider B. Intraarticular anterior cruciate ligament graft placement on the average most isometric line on the femur. Does it reproducibly restore knee kinematics? Am J Sports Med 1999; 27:329-34. [PMID: 10352768 DOI: 10.1177/03635465990270031001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In the past, there has been a plausible hypothesis that anterior cruciate ligament graft placement at isometric sites, such that the tibial and femoral attachment sites remain equidistant from each other throughout knee range of motion, would increase the likelihood of a satisfactory outcome. For a given tibial placement we wanted to determine whether placing the graft on the average of the most isometric femoral line, a fixed distance from the outlet of the intercondylar notch, would return normal laxity to all knees. The three-dimensional kinematics of seven cadaveric knees were measured for angles from full extension to 90 degrees of flexion at 15 degrees increments. Physiologic levels of quadriceps muscle forces were applied to the intact knee, after transection of the anterior cruciate ligament, and after ligament reconstruction with a patellar tendon graft. On average, the reconstruction was found to return anterior-posterior translation, internal-external rotation, and varus-valgus rotation to levels not significantly different from those of the intact knee. However, the ranges of the translation and rotations were large. Placing the graft on the average most isometric femoral line did not restore knee laxity to normal in all knees. This supports the need to customize graft placement in each knee at the time of surgery.
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Ritter A, Wenner P, Ho S, Whelan PJ, O'Donovan MJ. Activity patterns and synaptic organization of ventrally located interneurons in the embryonic chick spinal cord. J Neurosci 1999; 19:3457-71. [PMID: 10212306 PMCID: PMC6782253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Abstract
To investigate the origin of spontaneous activity in developing spinal networks, we examined the activity patterns and synaptic organization of ventrally located lumbosacral interneurons, including those whose axons project into the ventrolateral funiculus (VLF), in embryonic day 9 (E9)-E12 chick embryos. During spontaneous episodes, rhythmic synaptic potentials were recorded from the VLF and from spinal interneurons that were synchronized, cycle by cycle, with rhythmic ventral root potentials. At the beginning of an episode, ventral root potentials started before the VLF discharge and the firing of individual interneurons. However, pharmacological blockade of recurrent motoneuron collaterals did not prevent or substantially delay interneuron recruitment during spontaneous episodes. The synaptic connections of interneurons were examined by stimulating the VLF and recording the potentials evoked in the ventral roots, in the VLF, or in individual interneurons. Low-intensity stimulation of the VLF evoked a short-latency depolarizing potential in the ventral roots, or in interneurons, that was probably mediated mono- or disynaptically. At higher intensities, long-latency responses were recruited in a highly nonlinear manner, eventually culminating in the activation of an episode. VLF-evoked potentials were reversibly blocked by extracellular Co2+, indicating that they were mediated by chemical synaptic transmission. Collectively, these findings indicate that ventral interneurons are rhythmically active, project to motoneurons, and are likely to be interconnected by recurrent excitatory synaptic connections. This pattern of organization may explain the synchronous activation of spinal neurons and the regenerative activation of spinal networks when provided with a suprathreshold stimulus.
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Fedirchuk B, Wenner P, Whelan PJ, Ho S, Tabak J, O'Donovan MJ. Spontaneous network activity transiently depresses synaptic transmission in the embryonic chick spinal cord. J Neurosci 1999; 19:2102-12. [PMID: 10066263 PMCID: PMC6782567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/1998] [Revised: 12/28/1998] [Accepted: 01/05/1999] [Indexed: 02/11/2023] Open
Abstract
We examined the effects of spontaneous or evoked episodes of rhythmic activity on synaptic transmission in several spinal pathways of embryonic day 9-12 chick embryos. We compared the amplitude of synaptic potentials evoked by stimulation of the ventrolateral funiculus (VLF), the dorsal or ventral roots, before and after episodes of activity. With the exception of the short-latency responses evoked by dorsal root stimulation, the potentials were briefly potentiated and then reduced for several minutes after an episode of rhythmic activity. Their amplitude progressively recovered in the interval between successive episodes. The lack of post-episode depression in the short-latency component of the dorsal root evoked responses is probably attributable to the absence of firing in cut muscle afferents during an episode of activity. The post-episode depression of VLF-evoked potentials was mimicked by prolonged stimulation of the VLF, subthreshold for an episode of activity. By contrast, antidromically induced motoneuron firing and the accompanying calcium entry did not depress VLF-evoked potentials recorded from the stimulated ventral root. In addition, post-episode depression of VLF-evoked synaptic currents was observed in voltage-clamped spinal neurons. Collectively, these findings suggest that somatic postsynaptic activity and calcium entry are not required for the depression. We propose instead that the mechanism may involve a form of long-lasting activity-induced synaptic depression, possibly a combination of transmitter depletion and ligand-induced changes in the postsynaptic current accompanying transmitter release. This activity-dependent depression appears to be an important mechanism underlying the occurrence of spontaneous activity in developing spinal networks.
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Ho S. Sam Ho, MD: idealist, innovator, entrepreneur. Interview by Fitzhugh Mullan. JAMA 1999; 281:947-51. [PMID: 10078495 DOI: 10.1001/jama.281.10.947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Martin R, Kuzniecky R, Ho S, Hetherington H, Pan J, Sinclair K, Gilliam F, Faught E. Cognitive effects of topiramate, gabapentin, and lamotrigine in healthy young adults. Neurology 1999; 52:321-7. [PMID: 9932951 DOI: 10.1212/wnl.52.2.321] [Citation(s) in RCA: 269] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To study the acute and steady-state cognitive effects of three new antiepileptic drugs (AEDs): gabapentin, lamotrigine, and topiramate. BACKGROUND Several newer antiepileptic medications approved recently by the Food and Drug Administration are gaining attention as efficacious alternatives to established AEDs. Greater tolerability with fewer side effects are reported in some. However, the potential cognitive effects of these newer AEDs have received limited attention. METHODS Healthy young adults randomized to either of the three drugs were administered tests of attention, psychomotor speed, language, memory, and mood at baseline (predrug), acute single-dose period, and after 2 and 4 weeks on the drug. RESULTS Compared with baseline, the topiramate group had selective, statistically significant declines on measures of attention and word fluency at acute doses, whereas the other two AED groups had no performance changes. At the 2- and 4-week test periods, only the topiramate subjects continued to display neurocognitive effects from drug administration. CONCLUSIONS Results demonstrate potential acute and steady-state adverse cognitive effects for topiramate, whereas minimal effects were displayed for either gabapentin or lamotrigine in young healthy adults.
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Ho S, Johnson PJ, Leung WT, Lau WY. Combating hepatocellular carcinoma with an integrated approach. Chin Med J (Engl) 1999; 112:80-3. [PMID: 11593648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023] Open
Abstract
This short review summarizes an integrated approach to new methods of managing hepatocellular carcinoma (HCC) developed at our centre. HCC-specific isoforms of alpha-fetoprotein were detected by isoelectric focusing and their value in the differential diagnosis of early HCC on a background of chronic liver disease has been shown. Selective internal radiation therapy using yttrium-90 (90 Y) microspheres has been shown to be an effective treatment for inoperable HCC in a phase I and II study. A partition model for estimating the radiation doses from the 90 Y microspheres to the tumour and the non-tumorous liver during the therapy was then formulated, verified by correlating with intraoperative dosimetry, and evaluated in clinical settings. This permits 90 Y microspheres to be administered safely without the need of an open surgery and a randomized therapeutic controlled trial is in progress. Another randomized controlled trial using iodine-131 Lipiodol as a post-operative adjuvant therapy, aiming at reducing the recurrence rate is also on-going. HCC may be more effectively combated with a better understanding of its pathogenesis from chronic liver disease.
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Dowler R, Martin R, Ho S, Gilliam F, Faught E, Kuzniecky R. Neuropsychological profile associated with MRI-identified coexisting temporal lobe developmental malformations and hippocampal sclerosis. Arch Clin Neuropsychol 1999. [DOI: 10.1093/arclin/14.1.127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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