Displaying publications 21 - 38 of 38 in total

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  1. Yvonne-Tee GB, Rasool AH, Halim AS, Rahman AR
    Clin. Hemorheol. Microcirc., 2006;34(4):457-73.
    PMID: 16687786
    Given that functional abnormalities of the microcirculation are one of the primary abnormalities in cardiovascular disease pathogenesis, various noninvasive clinical tools have been developed recently to assess the microvascular function, particularly at the skin. The common techniques used to assess cutaneous microvascular function in vivo include capillaroscopy, venous occlusion plethysmography, and laser-Doppler instruments (laser-Doppler fluximetry and laser-Doppler imaging). These noninvasive techniques can be used as an early measure of functional abnormalities within the microvascular tree, predominantly in population at high risk for cardiovascular events. This review discusses some underlying application principle of these techniques, including its clinical significance, method reproducibility and limitations.
  2. Wong AR, Rasool AH, Abidin NZ, Noor AR, Quah BS
    J Paediatr Child Health, 2006 Mar;42(3):147-8.
    PMID: 16509918
    Human Immunodeficiency Virus (HIV)-related pulmonary hypertension is a relatively rare disease that can affect HIV sufferers. This is almost always associated with a poor outcome and death. An 18 month-old girl, probably the youngest on record, was diagnosed to have pulmonary hypertension (PHT) and retrospectively found to have HIV infection. Sildenafil was used to control her PHT and she remains alive even after 2 years.
  3. Yvonne-Tee GB, Rasool AH, Halim AS, Rahman AR
    J Pharmacol Toxicol Methods, 2005 Sep-Oct;52(2):286-92.
    PMID: 16125628
    Postocclusive reactive hyperemia in forearm skin is a commonly used model for studying microvascular reactivity function, particularly in the assessment of vascular effect of topically applied pharmacological substances. In this study, we investigated the reproducibility of several different laser-Doppler-derived parameters in the measurement of postocclusive reactive hyperemia at forearm skin in healthy subjects.
  4. Sanip Z, Hanaffi SH, Ahmad I, Yusoff SS, Rasool AH, Yusoff HM
    Tob Induc Dis, 2015;13(1):32.
    PMID: 26346914 DOI: 10.1186/s12971-015-0052-9
    BACKGROUND: Studies have demonstrated that secondhand smoke (SHS) exposure could impair endothelial function. However, the effect of SHS exposure specifically on microvascular endothelial function is not well understood. This study aimed to determine the effects of SHS exposure on microvascular endothelial function among non-smoking, generally healthy women.

    FINDINGS: We studied 127 women; and based on their hair nicotine levels measured using gas chromatography-mass spectrometry, 25 of them were categorized as having higher hair nicotine levels, 25 were grouped as having lower hair nicotine and 77 women were grouped into the non-detected group. The non-detected group did not have detectable levels of hair nicotine. Anthropometry, blood pressure (BP), lipid profile and high-sensitivity C-reactive protein (hsCRP) were measured accordingly. Microvascular endothelial function was assessed non-invasively using laser Doppler fluximetry and the process of iontophoresis involving acetylcholine and sodium nitroprusside as endothelium-dependent and endothelium-independent vasodilators respectively. The mean hair nicotine levels for higher and lower hair nicotine groups were 0.74 (1.04) and 0.05 (0.01) ng/mg respectively. There were no significant differences in anthropometry, BP, lipid profile and hsCRP between these groups. There were also no significant differences in the microvascular perfusion and endothelial function between these groups.

    CONCLUSION: In this study, generally healthy non-smoking women who have higher, lower and non-detected hair nicotine levels did not show significant differences in their microvascular endothelial function. Low levels of SHS exposure among generally healthy non-smoking women may not significantly impair their microvascular endothelial function.

  5. Mokhtar SS, Vanhoutte PM, Leung SW, Suppian R, Yusof MI, Rasool AH
    Eur J Pharmacol, 2016 Feb 15;773:78-84.
    PMID: 26825543 DOI: 10.1016/j.ejphar.2016.01.013
    Diabetes is associated with endothelial dysfunction, which is characterized by impaired endothelium-dependent relaxations. The present study aimed to examine the role of nitric oxide (NO), prostacyclin and endothelium-dependent hyperpolarization (EDH), in the relaxation of ventral tail arteries of rats under diabetic conditions. Relaxations of tail arteries of control and diabetic rats were studied in wire myograph. Western blotting and immunostaining were used to determine the presence of proteins. Acetylcholine-induced relaxations were significantly smaller in arteries of diabetic compared to control rats (Rmax; 70.81 ± 2.48% versus 85.05 ± 3.15%). Incubation with the combination of non-selective cyclooxygenase (COX) inhibitor, indomethacin and potassium channel blockers, TRAM 34 and UCL 1684, demonstrated that NO-mediated relaxation was attenuated significantly in diabetic compared to control rats (Rmax; 48.47 ± 5.84% versus 68.39 ± 6.34%). EDH-type (in the presence of indomethacin and NO synthase inhibitor, LNAME) and prostacyclin-mediated (in the presence of LNAME plus TRAM 34 and UCL 1684) relaxations were not significantly reduced in arteries of diabetic compared to control rats [Rmax: (EDH; 17.81 ± 6.74% versus 34.16 ± 4.59%) (prostacyclin; 15.85 ± 3.27% versus 17.23 ± 3.75%)]. Endothelium-independent relaxations to sodium nitroprusside, salbutamol and prostacyclin were comparable in the two types of preparations. Western blotting and immunostaining indicated that diabetes diminished the expression of endothelial NO synthase (eNOS), while increasing those of COX-1 and COX-2. Thus, since acetylcholine-induced NO-mediated relaxation was impaired in diabetes because of reduced eNOS protein expression, pharmacological intervention improving NO bioavailability could be useful in the management of diabetic endothelial dysfunction.
  6. Tee GB, Rasool AH, Halim AS, Rahman AR
    J Pharmacol Toxicol Methods, 2004 Jul-Aug;50(1):73-8.
    PMID: 15233971 DOI: 10.1016/j.vascn.2004.02.002
    Human postocclusive forearm skin reactive hyperemia is not only a potential means of identifying early signs of cardiovascular diseases, it can also be used in the assessment of local microvascular response to topically applied compounds on skin. The method is not fully characterized. In this study, we investigated the influence of occlusion time on postocclusive forearm skin reactive hyperemia using laser Doppler fluximetry (LDF).
  7. Mudassar Imran Bukhari S, Yew KK, Thambiraja R, Sulong S, Ghulam Rasool AH, Ahmad Tajudin LS
    Ther Adv Ophthalmol, 2019 08 22;11:2515841419868100.
    PMID: 31489400 DOI: 10.1177/2515841419868100
    Purpose: To determine the role of microvascular endothelial dysfunction as risk factor for primary open angle glaucoma.

    Methods: A cross-sectional study was conducted involving 114 Malay patients with POAG seen at the eye clinic of Hospital Universiti Sains Malaysia. Patients aged between 40 and 80 years who were diagnosed with other types of glaucoma, previous glaucoma filtering surgery or other surgeries except uncomplicated cataract surgery and pterygium surgery were excluded. A total of 101 patients who were followed up for dry eyes, age-related cataracts or post cataracts extraction surgery were recruited as control subjects. Those with family history of glaucoma or glaucoma suspect were excluded. Microvascular endothelial function was assessed using laser Doppler fluximetry and the process of iontophoresis. Iontophoresis with acetylcholine (ACh) and sodium nitroprusside (SNP) was used to measure microvascular endothelium-dependent and endothelium-independent vasodilatations, respectively.

    Results: In general, POAG patients demonstrated lower ACh% and AChmax values compared with controls. There was significant difference in microvascular endothelial function [ACh%: mean, 95% confidence interval = 503.1 (378.0, 628.3), and AChmax: mean, 95% confidence interval = 36.8 (30.2, 43.5)] between primary open angle glaucoma cases (p 

  8. Rasool AH, Ghazali DM, Abdullah H, Halim AS, Wong AR
    Microvasc Res, 2009 Sep;78(2):230-4.
    PMID: 19481100 DOI: 10.1016/j.mvr.2009.05.005
    Post occlusive skin reactive hyperemia (PORH) is a tool used to assess microcirculation. Endothelial nitric oxide synthase (eNOS) mediates nitric oxide (NO) production; polymorphism of the eNOS gene may affect response to the PORH process. This study aims to determine whether eNOS G894T gene polymorphism affects response to skin PORH. 230 normotensive male and females between 18 and 40 years participated in this cross-sectional study. 170 subjects were of the homozygous GG genotype, whereas 60 were of the GT genotype. Skin PORH was performed by occlusion of the upper arm at 200 mm Hg for 3 min. Skin perfusion and temperature were monitored before, during and after occlusion release using the laser Doppler fluximetry. There were no significant differences between genotypes in their baseline blood pressure, serum cholesterol, BMI and age. Maximum change in perfusion after occlusion release (PORHmax) for the GG and GT genotypes were not significantly different at 50.15+/-1.29 vs. 47.92+/-2.17 AU; ANCOVA, p=0.351. Peak perfusion (PORHpeak) were also not significantly different between the two genotypes (61.23+/-1.36 vs. 57.72+/-2.32 AU; p=0.169). Minimum baseline perfusion were however higher in the GG compared to the GT genotype (10.83+/-0.29 vs. 9.61+/-0.50, p=0.029). We conclude that microvascular reactivity, assessed by change in perfusion after temporary ischemia was not significantly different between the GG and GT genotypes of the eNOS G894T gene. eNOS 894T allele carriers however, have lower baseline perfusion compared to the homozygous G894 allele carrier.
  9. Rasool AH, Yuen KH, Yusoff K, Wong AR, Rahman AR
    J Nutr Sci Vitaminol (Tokyo), 2006 Dec;52(6):473-8.
    PMID: 17330512
    Tocotrienols are a class of vitamin E reported to be potent antioxidants, besides having the ability to inhibit the HMG-CoA reductase enzyme. This study assessed the effects of 3 doses of tocotrienol-rich vitamin E (TRE) on plasma tocotrienol isomer concentration, arterial compliance, plasma total antioxidant status (TAS), aortic systolic blood pressure (ASBP), serum total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) in healthy males.

    METHODOLOGY: This randomised, blinded end-point, placebo-controlled clinical trial with a parallel design involved 36 healthy male subjects who took either an oral placebo or TRE at doses of 80, 160 or 320 mg daily for 2 mo. Baseline and end-of-treatment measurements of vitamin E concentration, arterial compliance [assessed by aortic femoral pulse wave velocity (PWV) and augmentation index (AI)], ASBP, plasma TAS, serum TC and LDL-C were taken.

    RESULTS: Baseline tocotrienol isomer concentrations were low and not detectable in some subjects. Upon supplementation, all TRE-treated groups showed significant difference from placebo for their change in alpha, gamma and delta tocotrienol concentrations from baseline to end of treatment. There was a linear dose and blood level relationship for all the isomers. There was no significant difference between groups for their change in PWV, AI, plasma TAS, ASBP, TC or LDL-C from baseline to end of treatment. Groups 160 mg (p = 0.024) and 320 mg (p = 0.049) showed significant reductions in their ASBP. Group 320 mg showed a significant 9.2% improvement in TAS.

    CONCLUSION: TRE at doses up to 320 mg daily were well tolerated. Treatment significantly increased alpha, delta, and gamma tocotrienol concentrations but did not significantly affect arterial compliance, plasma TAS, serum TC or LDL-C levels in normal subjects.

  10. Bukhari SM, Kiu KY, Thambiraja R, Sulong S, Rasool AH, Liza-Sharmini AT
    Eye (Lond), 2016 Dec;30(12):1579-1587.
    PMID: 27540832 DOI: 10.1038/eye.2016.185
    PurposeThe role of microvascular endothelial dysfunction on severity of primary open angle glaucoma (POAG) was investigated in this study.Patients and methodsA prospective cohort study was conducted. One hundred and fourteen ethnically Malay patients (114 eyes) with POAG treated at the eye clinic of Hospital University Sains Malaysia between April 2012 and December 2014 were recruited. Patients aged between 40 and 80 years with two consecutive reliable and reproducible Humphrey visual field 24-2 analyses were selected. Patients who were diagnosed with any other type of glaucoma, previous glaucoma-filtering surgery, or other surgeries except uncomplicated cataract and pterygium surgery were excluded. Humphrey visual field analysis 24-2 was used to stratify the severity of glaucoma using Advanced Glaucoma Intervention Study (AGIS) score at the time of recruitment. Microvascular endothelial function was assessed using Laser Doppler fluximetry and iontophoresis. Iontophoresis process with acetylcholine (ACh) and sodium nitroprusside (SNP) was used to measure microvascular endothelium-dependent and -independent vasodilatation, respectively.ResultsBased on the AGIS score, 55 patients showed mild glaucoma, with 29 moderate and 30 severe. There was statistically significant difference in microvascular endothelial function (ACh% and AChmax) between mild and moderate POAG cases (P=0.023) and between mild and severe POAG cases (P<0.001). There was negative correlation between microvascular endothelial function and severity of POAG (r=-0.457, P<0.001).ConclusionMicrovascular endothelial dysfunction may have a role in influencing the severity of POAG in Malay patients.

    Study site: Eye clinic Hospital Universiti Sains Malaysia (HUSM)
  11. Ibrahim NN, Rasool AH, Wong AR, Rahman AR
    Clin Chim Acta, 2009 Nov;409(1-2):62-6.
    PMID: 19723516 DOI: 10.1016/j.cca.2009.08.018
    Pulse wave analysis (PWA) combined with beta(2)-agonist challenge has recently been used to assess endothelial function. beta-2 adrenergic receptor (beta(2)AR) polymorphisms may affect response to beta(2)-agonist. We determined whether beta(2)AR polymorphisms influence endothelial response in our model using PWA and salbutamol.
  12. Chai SC, Sulaiman WAW, Saad AZM, Rasool AH, Shokri AA
    Indian J Nephrol, 2018;28(6):421-426.
    PMID: 30647495 DOI: 10.4103/ijn.IJN_402_17
    Maturation of arteriovenous fistula (AVF) involves complex vascular remodeling. In this study, we evaluated the changes of skin microvascular perfusion over the extremity with AVF maturation using the laser Doppler fluximetry (LDF). A total of 45 patients with chronic kidney disease, Stages IV-V, were included; they had undergone AVF creation from July 2014 to June 2016 at our institute. The measurement of skin microvascular perfusion was accomplished proximal and distal to the fistula anastomosis site: pre- and post-operative day 1, week 2, week 6, and week 12. Thirty-two patients with mean age of 55.6 had achieved AVF maturation. There were 40.6% radial-based and 59.4% brachial-based AVF. There was a 32.8% reduction of mean skin perfusion distal to the fistula by day 1 compared to the baseline perfusion; however, perfusion increased 47% by week 2 compared to day 1 and no dramatic change was subsequently noted. There was an increase of mean skin perfusion, proximal to fistula anastomosis, over 12 weeks with 35.8% at day 1 from the baseline. However, the changes of the mean skin perfusion were not statistically significant. There was no significant relation of skin perfusion changes with the type of fistula, diabetes mellitus, hypertension, and hyperlipidemia. LDF successfully detected the subclinical change of skin microvascular perfusion in relation to AVF creation. Reduction of skin perfusion distal to the fistula suggests that in patients with existing perfusion inadequacy of extremities, they may experience ischemic symptoms as early as day 1 postoperation, and require close monitoring for distal limb ischemic-related complications.
  13. Sanip Z, Pahimi N, Bokti NA, Yusof Z, Mohamed MS, W Isa WYH, et al.
    Microcirculation, 2023 Apr 20.
    PMID: 37080549 DOI: 10.1111/micc.12807
    OBJECTIVE: This study aimed to determine whether peripheral microvascular reactivity is impaired in patients with nonobstructive coronary artery disease (NOCAD).

    METHODS: Stable patients presenting with angina were recruited and, based on results from coronary angiography, were categorized into OCAD (coronary stenosis of ≥50%) and NOCAD (stenosis <50%) groups. A control group with no history of angina was also recruited. Forearm skin microvascular reactivity was measured using the laser Doppler blood perfusion monitor and the process of postocclusive skin reactive hyperemia (PORH).

    RESULTS: Patients were categorized into OCAD (n = 42), NOCAD (n = 40), and control (n = 39) groups. Compared with the control group, the PORH perfusion percent change (PORH% change) was significantly lower in the OCAD and NOCAD groups. No significant differences were noted between the OCAD and NOCAD groups. Additionally, the NOCAD group without any coronary obstruction takes a longer time to reach peak perfusion and had lower PORH% change compared with the nonangina control group.

    CONCLUSION: Angina patients with NOCAD have microvascular dysfunction as demonstrated by reduced magnitude of reperfusion with an ischemic stimulus. NOCAD patients without coronary obstruction also displayed a slower response to reperfusion.

  14. Zainudin AM, Ghulam Rasool AH, Mat Nor MZ, Hassan NB, Muhamad R, Wan Mohamed WMI
    Malays J Med Sci, 2024 Apr;31(2):98-112.
    PMID: 38694587 DOI: 10.21315/mjms2024.31.2.9
    BACKGROUND: Many patients with type 2 diabetes mellitus (T2DM) do not achieve the desired glycaemic control despite being treated with insulin. Studies found this due to an improper understanding of insulin function, its intensification process and patients' negative perspective on insulin. We developed an education module to enhance adherence to insulin therapy.

    METHODS: This study applied a mixed design. It was conducted in three phases: i) Phase I: literature search and focus group discussions (FGDs), ii) Phase II: module development and iii) Phase III: content and face validation of Universiti Sains Malaysia-Insulin Adherence Module (USM-IAM). FGDs were used to gather patients' opinions. All researchers repeatedly discussed about the module content and arrangement, the words and images used, and the grammar in producing the final draft. Specialists and target audience performed content and face validation of the module.

    RESULTS: Thirty-six participants were involved in the FGDs. Data saturation was achieved at the 4th FGD. Three themes emerged from qualitative data analysis and were incorporated into the module. USM-IAM was finalised with five units. The content validity index (CVI) was 0.92, while face validity agreements were between 86% and 97%.

    CONCLUSION: The CVI and face agreement for USM-IAM exceed the cut-off point for a sound module. It has good potential to be used as a resource for educating patients in enhancing insulin adherence.

  15. Rasool AH, Abdul Rahman AS, Abd Ghaffar NA, Nik Mahmood NM, Wong AR
    Malays J Med Sci, 2010 Oct;17(4):14-9.
    PMID: 22135556 MyJurnal
    Post-occlusive skin reactive hyperaemia (PORH) is a model used to assess microvascular reactivity. This study aims to compare PORH response among pregnant hypercholesterolaemic patients with age and gestational age-matched controls.
  16. Al-Tahami BA, Ismail AA, Bee YT, Awang SA, Salha Wan Abdul Rani WR, Sanip Z, et al.
    Clin. Hemorheol. Microcirc., 2015;59(4):323-34.
    PMID: 24002121 DOI: 10.3233/CH-131765
    INTRODUCTION: Obesity is associated with impaired microvascular endothelial function. We aimed to determine the effects of orlistat and sibutramine treatment on microvascular endothelial function, anthropometric and lipid profile, blood pressure (BP), and heart rate (HR).
    METHODS: 76 subjects were recruited and randomized to receive orlistat 120 mg three times daily or sibutramine 10 mg daily for 9 months. Baseline weight, BMI, BP, HR and lipid profile were taken. Microvascular endothelial function was assessed using laser Doppler fluximetry and iontophoresis process. Maximum change (max), percent change (% change) and peak flux (peak) in perfusion to acetylcholine (ACh) and sodium nitroprusside (SNP) iontophoresis were used to quantify endothelium dependent and independent vasodilatations.
    RESULTS: 24 subjects in both groups completed the trial. After treatment, weight and BMI were decreased for both groups. AChmax, ACh % change and ACh peak were increased in orlistat-treated group but no difference was observed for sibutramine-treated group. BP and total cholesterol (TC) were reduced for orlistat-treated group. HR was reduced for orlistat-treated group but was increased in sibutramine-treated group.
    CONCLUSION: 9 months treatment with orlistat significantly improved microvascular endothelial function. This was associated with reductions in weight, BMI, BP, HR, TC and low density lipoprotein cholesterol. No effect was seen in microvascular endothelial function with sibutramine.
    KEYWORDS: Microvascular endothelial function; obesity; orlistat; sibutramine
  17. Mokhtar SS, Vanhoutte PM, Leung SW, Yusof MI, Wan Sulaiman WA, Mat Saad AZ, et al.
    Nitric Oxide, 2016 Feb 29;53:35-44.
    PMID: 26768833 DOI: 10.1016/j.niox.2015.12.007
    Diabetes impairs endothelium-dependent relaxations. The present study evaluated the contribution of different endothelium-dependent relaxing mechanisms to the regulation of vascular tone in subcutaneous blood vessels of humans with Type 2 diabetes mellitus. Subcutaneous arteries were isolated from tissues of healthy controls and diabetics. Vascular function was determined using wire myography. Expressions of proteins were measured by Western blotting and immunostaining. Endothelium-dependent relaxations to acetylcholine were impaired in arteries from diabetics compared to controls (P = 0.009). Acetylcholine-induced nitric oxide (NO)-mediated relaxations [in the presence of an inhibitor of cyclooxygenases (COX; indomethacin) and small and intermediate conductance calcium-activated potassium channel blockers (UCL1684 and TRAM 34, respectively)] were attenuated in arteries from diabetics compared to controls (P 
  18. Safiah Mokhtar S, M Vanhoutte P, W S Leung S, Imran Yusof M, Wan Sulaiman WA, Zaharil Mat Saad A, et al.
    Tohoku J Exp Med, 2013 11;231(3):217-22.
    PMID: 24225501
    Diabetic endothelial dysfunction is characterized by impaired endothelium-dependent relaxation. In this study, we measured the expression of endothelial nitric oxide synthase (eNOS), cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), prostacyclin synthase (PGIS), and prostacyclin receptor (IP) in subcutaneous arteries of type-2 diabetic and non-diabetic patients. Subcutaneous arteries were dissected from tissues from seven diabetics (4 males and 3 females) and seven non-diabetics (5 males and 2 females) aged between 18 to 65 years, who underwent lower limb surgical procedures. Diabetics had higher fasting blood glucose compared to non-diabetics, but there were no differences in blood pressure, body mass index and age. Patients were excluded if they had uncontrolled hypertension, previous myocardial infarction, coronary heart disease, renal or hepatic failure and tumor. The relative expression levels of eNOS, COX-1, COX-2, PGIS and IP receptor were determined by Western blotting analysis, normalized with the β-actin level. Increased expression of COX-2 was observed in subcutaneous arteries of diabetics compared to non-diabetics, whereas the expression levels of eNOS and PGIS were significantly lower in diabetics. There were no significant differences in expression levels of COX-1 and IP receptor between the two groups. Immunohistochemical study of subcutaneous arteries showed that the intensities of eNOS and PGIS staining were lower in diabetics, with higher COX-2 staining. In conclusion, type-2 diabetes is associated with higher COX-2 expression, but lower eNOS and PGIS expression in subcutaneous arteries. These alterations may lead to impaired endothelium-dependent vasodilatation, and thus these proteins may be potential targets for protection against the microvascular complications of diabetes.
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