MyMedR

Fulltext Characteristics of hypertension in obstructive sleep apnea: An Asian experience

Hoshide S, Kario K, Chia YC, Siddique S, Buranakitjaroen P, Tsoi K, et al.

J Clin Hypertens (Greenwich), 2021 03;23(3):489-495.

Obstructive sleep apnea (OSA) is a risk of hypertension and is associated with cardiovascular disease (CVD) incidence. In Asian countries, the prevalence of OSA is high, as in Western countries. When blood pressure (BP) is evaluated in OSA individuals using ambulatory BP monitoring (ABPM), the BP phenotype often indicates abnormal BP variability, such as increased nighttime BP or abnormal diurnal BP variation, that is, non-dipper pattern, riser pattern, and morning BP surge, and all these conditions have been associated with increased CVD events. Asians have a higher prevalence of increased nighttime BP or morning BP surge than Westerners. Therefore, this review paper focused on OSA and hypertension from an Asian perspective to investigate the importance of the association between OSA and hypertension in the Asian population. Such abnormal BP variability has been shown to be associated with progression of arterial stiffness, and this association could provoke a vicious cycle between abnormal BP phenotypes and arterial stiffness, a phenomenon recognized as systemic hemodynamic atherothrombotic syndrome (SHATS). OSA may be one of the background factors that augment SHATS. An oxygen-triggered nocturnal oscillometric BP measurement device combined with a pulse oximeter for continuous SpO2 monitoring could detect BP variability caused by OSA. In addition to treating the OSA, accurate and reliable detection and treatment of any residual BP elevation and BP variability caused by OSA would be necessary to prevent CVD events. However, more detailed detection of BP variability, such as beat-by-beat BP monitoring, would further help to reduce CV events.

Fulltext Clinical significance of nocturnal home blood pressure monitoring and nocturnal hypertension in Asia

Fujiwara T, Hoshide S, Tomitani N, Cheng HM, Soenarta AA, Turana Y, et al.

J Clin Hypertens (Greenwich), 2021 03;23(3):457-466.

PMID: 33591641 DOI: 10.1111/jch.14218

Nocturnal home blood pressure (BP) monitoring has been used in clinical practice for ~20 years. The authors recently showed that nocturnal systolic BP (SBP) measured by a home BP monitoring (HBPM) device in a Japanese general practice population was a significant predictor of incident cardiovascular disease (CVD) events, independent of office and morning home SBP levels, and that masked nocturnal hypertension obtained by HBPM (defined as nocturnal home BP ≥ 120/70 mmHg and average morning and evening BP

Serum and salivary IgA antibodies against a defined epitope of the Epstein-Barr virus nuclear antigen (EBNA) are elevated in nasopharyngeal carcinoma

Foong YT, Cheng HM, Sam CK, Dillner J, Hinderer W, Prasad U

Int J Cancer, 1990 Jun 15;45(6):1061-4.

PMID: 1693600

The Epstein-Barr virus nuclear antigen I (EBNA I) is the only latent EBV antigen consistently expressed in malignant tissues of the nasopharynx. A 20-amino-acid synthetic peptide, p107 contains a major epitope of EBNA I. We tested sera from 210 patients with nasopharyngeal carcinoma (NPC) and from 128 normal individuals (NHS) for IgA antibodies to p107 using an enzyme-linked immunosorbent assay (ELISA). Whereas 191/210 (91%) of NPC patients had IgA antibodies to p107, only 17/128 (13.3%) of NHS had such antibodies and only 6/57 (10.5%) of sera from patients with malignancies other than NPC had IgA-p107 reactivity. Thirty-nine salivary samples from 46 NPC patients (84.8%) also contained IgA-p107 antibodies whereas only 3/42 (7.1%) of normal saliva samples were IgA-p107 positive. The results suggest that IgA antibodies to EBNA I may become a useful, easily measurable, marker for NPC.

Fulltext Alpha-tocotrienol is the most abundant tocotrienol isomer circulated in plasma and lipoproteins after postprandial tocotrienol-rich vitamin E supplementation

Fairus S, Nor RM, Cheng HM, Sundram K

Nutr J, 2012;11:5.

PMID: 22252050 DOI: 10.1186/1475-2891-11-5

Tocotrienols (T3) and tocopherols (T), both members of the natural vitamin E family have unique biological functions in humans. T3 are detected in circulating human plasma and lipoproteins, although at concentrations significantly lower than α-tocopherol (α-T). T3, especially α-T3 is known to be neuropotective at nanomolar concentrations and this study evaluated the postprandial fate of T3 and α-T in plasma and lipoproteins.

Antioxidant status following postprandial challenge of two different doses of tocopherols and tocotrienols

Fairus S, Cheng HM, Sundram K

J Integr Med, 2020 Jan;18(1):68-79.

PMID: 31812339 DOI: 10.1016/j.joim.2019.11.005

OBJECTIVE: Tocotrienols (T3s) have been hypothesized to have greater antioxidant capacity than tocopherols (Ts) due to differences in biokinetics that affect their absorption and function. The present trial compares the antioxidant effectiveness following postprandial challenge of two different doses of α-T or palm T3-rich fraction (TRF) treatments and evaluates their dose-response effects on antioxidant status.

METHODS: Ten healthy volunteers were given four different doses of vitamin E formulations (268 mg α-T, 537 mg α-T, 263 mg TRF or 526 mg TRF) in a cross-over postprandial trial. Blood was sampled at 0, 2, 4, 5, 6 and 8 hours after meal consumption and plasma antioxidant status including total glutathione, superoxide dismutase, malondialdehyde (MDA), ferric reducing antioxidant potential and trolox-equivalent antioxidant capacity, was analyzed.

RESULTS: Supplementation with the different doses of either α-T or TRF did not significantly improve overall antioxidant status. There was no significant difference in overall antioxidant status among treatments at the different doses compared. However, a significant dose-response effect was observed for plasma MDA throughout the 8-hour postprandial period. MDA was significantly lower after the 537 mg α-T treatment, compared to the 268 mg α-T treatment; it was also lower after the 526 mg TRF treatment compared to the 263 mg TRF treatment (P

Postprandial metabolic fate of tocotrienol-rich vitamin E differs significantly from that of alpha-tocopherol

Fairus S, Nor RM, Cheng HM, Sundram K

Am J Clin Nutr, 2006 Oct;84(4):835-42.

PMID: 17023711

BACKGROUND: The detection of tocotrienols in human plasma has proven elusive, and it is hypothesized that they are rapidly assimilated and redistributed in various mammalian tissues.

OBJECTIVE: The primary study objective was to evaluate the postprandial fate of tocotrienols and alpha-tocopherol in human plasma and lipoproteins.

DESIGN: Seven healthy volunteers (4 males, 3 females) were administered a single dose of vitamin E [1011 mg palm tocotrienol-rich fraction (TRF) or 1074 mg alpha-tocopherol] after a 7-d conditioning period with a tocotrienol-free diet. Blood was sampled at baseline (fasted) and 2, 4, 5, 6, 8, and 24 h after supplementation. Concentrations of tocopherol and tocotrienol isomers in plasma, triacylglycerol-rich particles (TRPs), LDLs, and HDLs were measured at each interval.

RESULTS: After intervention with TRF, plasma tocotrienols peaked at 4 h (4.79 +/- 1.2 microg/mL), whereas alpha-tocopherol peaked at 6 h (13.46 +/- 1.68 microg/mL). Although tocotrienols were similarly detected in TRPs, LDLs, and HDLs, tocotrienol concentrations were significantly lower than alpha-tocopherol concentrations. In comparison, plasma alpha-tocopherol peaked at 8 h (24.3 +/- 5.22 microg/mL) during the alpha-tocopherol treatment and emerged as the major vitamin E isomer detected in plasma and lipoproteins during both the TRF and the alpha-tocopherol treatments.

CONCLUSIONS: Tocotrienols are detected in postprandial plasma, albeit in significantly lower concentrations than is alpha-tocopherol. This finding confirms previous observations that, in the fasted state, tocotrienols are not detected in plasma. Tocotrienol transport in lipoproteins appears to follow complex biochemically mediated pathways within the lipoprotein cascade.

Fulltext Antioxidant and cytotoxic activities of three species of tropical seaweeds

Chia YY, Kanthimathi MS, Khoo KS, Rajarajeswaran J, Cheng HM, Yap WS

BMC Complement Altern Med, 2015;15:339.

PMID: 26415532 DOI: 10.1186/s12906-015-0867-1

Three species of seaweeds (Padina tetrastromatica, Caulerpa racemosa and Turbinaria ornata) are widely consumed by Asians as nutraceutical food due to their antioxidant properties. Studies have shown that these seaweeds exhibit bioactivities which include antimicrobial, antiviral, anti-hypertensive and anticoagulant activities. However, investigations into the mechanisms of action pertaining to the cytotoxic activity of the seaweeds are limited. The aim of this study was to determine the antioxidant and cytotoxic activities of whole extracts of P. tetrastromatica, C. racemosa and T. ornata, including the cellular events leading to the apoptotic cell death of the extract treated-MCF-7 cells. Bioassay guided fractionation was carried out and the compounds identified.

Fulltext Comparison of guidelines for the management of hypertension: Similarities and differences between international and Asian countries; perspectives from HOPE-Asia Network

Chia YC, Turana Y, Sukonthasarn A, Zhang Y, Shin J, Cheng HM, et al.

J Clin Hypertens (Greenwich), 2021 03;23(3):422-434.

PMID: 33634570 DOI: 10.1111/jch.14226

Guidelines on the management of hypertension have been developed by various professional bodies and institutions to primarily address the issues of diagnosis, treatment, and control in order to rationalize and improve the management of hypertension. Hypertension guidelines across the world have recently been updated following the new and controversial lower blood pressure threshold of ≥130/80 mmHg for the diagnosis of hypertension adopted by the Americans. While there are differences between the major as well as between the Asian national guidelines, there were also many similarities. This paper discusses and highlights the differences and similarities between the major international guidelines of the American College of Cardiology/American Heart Association, of the European Society of Cardiology/European Society of Hypertension, and of the International Society of Hypertension and also compares them with the Asian guidelines.

Fulltext Misconceptions highlighted among medical students in the annual International Intermedical School Physiology Quiz

Cheng HM, Durairajanayagam D

Adv Physiol Educ, 2012 Sep;36(3):229-32.

PMID: 22952263 DOI: 10.1152/advan.00089.2011

Fulltext Stimulating student interest in physiology: the intermedical school physiology quiz

Cheng HM

Adv Physiol Educ, 2010 Mar;34(1):20-1.

PMID: 20237230 DOI: 10.1152/advan.00096.2009

Singing and learning physiology

Cheng HM

Med Teach, 2010 Jan;32(1):91-2.

PMID: 20104662

Cryptic natural autoantibodies and co-potentiators

Cheng HM, Chamley L

Autoimmun Rev, 2008 Jun;7(6):431-4.

PMID: 18558357 DOI: 10.1016/j.autrev.2008.03.011

Natural autoantibodies are normal components of the humoral arm of the immune system found in clinically healthy individuals. There are two subpopulations of natural antibodies, including an overt group of antibodies that are readily detected in unfractionated normal human sera. The other natural antibody subgroup is revealed by physico or biochemical treatment of normal human sera in vitro. Unmasking of this latter cryptic natural autoantibodies (cNA) may occur in vivo by local factors in the tissue environment of disease states. The masking cryptic factors may be immunoglobulin (Ig) or non-Ig in nature. These factors may either be co-inhibitors or co-enhancers of cNA. In the heat-potentiated binding of natural anti-phospholipid antibodies, apolipoprotein H (beta 2-glycoprotein I) appears to act as a co-enhancer. The immuno-relationship between the in vitro and in vivo cNA phenomenon remains to be elucidated.

Fulltext Physongogy

Cheng HM

Adv Physiol Educ, 2008 Dec;32(4):303.

PMID: 19047507 DOI: 10.1152/advan.90110.2008

Fulltext Update on the growth of the International Intermedical School Physiology Quiz

Cheng HM, Hoe SZ

Adv Physiol Educ, 2016 Jun;40(2):198-9.

PMID: 27068996 DOI: 10.1152/advan.00186.2015

Cryptic antiphospholipid autoantibodies and serum co-inhibitors

Cheng HM

Autoimmunity, 1994;19(2):127-33.

PMID: 7772702 DOI: 10.3109/08916939409009540

Natural cryptic autoantibodies

Cheng HM

Autoimmunity, 1998;27(2):99-108.

PMID: 9583741

Oxidized LDL, placental trophoblast and B2-glycoprotein I

Cheng HM, Chamley LW

Proc. Soc. Exp. Biol. Med., 1998 Sep;218(4):277.

PMID: 9714070

Heat inactivation of serum potentiates anti-cardiolipin antibody binding in ELISA

Cheng HM, Ngeow YF, Sam CK

J Immunol Methods, 1989 Nov 30;124(2):235-8.

PMID: 2600427

Heat treatment of sera at 56 degrees C for 30 min results in positive ELISA reactions for anti-cardiolipin antibody (aCL) in sera that had undetectable or low levels of aCL before heat inactivation. The positive, potentiated reactivity of the heated sera in the aCL ELISA could be inhibited with the cardiolipin antigen and was abolished by prior IgG depletion using staphylococcal protein A. The heat-potentiating effect of aCL binding in ELISA was evident in both normal human sera and clinical sera including sera from patients with systemic lupus erythematosus and syphilis.

IgA antiphospholipid antibodies in normal human saliva cross-react with bacterial lipopolysaccharide

Cheng HM, Ngeow YF

Int Arch Allergy Immunol, 1993;101(3):297-8.

PMID: 8324391

Detection of antiphospholipid autoantibody in systemic lupus erythematosus is temperature-dependent

Cheng HM, Wang F

Immunol Invest, 1989 11 1;18(9-10):1121-7.

PMID: 2613288

Non-reactive SLE sera in an ELISA for anticardiolipin antibody (aCL) retested positive in the immunoassay when the sera were first heat-inactivated at 56 degrees C for 30 minutes. This was not a false positive phenomenon since the positive ELISA reactivity of the heated SLE sera was markedly reduced by inhibition with the cardiolipin antigen. Furthermore, the heat-potentiated ELISA reaction was abolished by prior IgG depletion of the SLE sera with Protein A preparation. The unmasked aCL in the heat-treated SLE sera also exhibited selective binding in ELISA to other negatively-charged phospholipids, namely phosphatidylserine and phosphatidic acid but not against either phosphatidylcholine or phosphatidyl-ethanolamine. The data strongly indicate an interaction between antiphospholipid antibodies and heat-sensitive serum component(s), a reduction of the latter resulting in the ELISA detection of the autoantibody.

Displaying publications 41 - 60 of 67 in total