Displaying publications 1 - 20 of 90 in total

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  1. Sundaram A, Siew Keah L, Sirajudeen KN, Singh HJ
    Hypertens Res, 2013 Mar;36(3):213-8.
    PMID: 23096233 DOI: 10.1038/hr.2012.163
    Although oxidative stress has been implicated in the pathogenesis of hypertension in spontaneously hypertensive rats (SHRs), there is little information on the levels of primary antioxidant enzymes status (AOEs) in pre-hypertensive SHR. This study therefore determined the activities of primary AOEs and their mRNA levels, levels of hydrogen peroxide (H2O2), malondialdehyde (MDA) and total antioxidant status (TAS) in whole kidneys of SHR and age-matched Wistar-Kyoto (WKY) rats aged between 2 and 16 weeks. Compared with age-matched WKY rats, catalase (CAT) activity was significantly higher from the age of 2 weeks (P<0.001) and glutathione peroxide (GPx) activity was lower from the age of 3 weeks (P<0.001) in SHR. CAT mRNA levels were significantly higher in SHR aged 2, 4, 6 and 12 weeks. GPx mRNA levels were significantly lower in SHR at 8 and 12 weeks. Superoxide dismutase activity or its mRNA levels were not different between the two strains. H2O2 levels were significantly lower in SHR from the age of 8 weeks (P<0.01). TAS was significantly higher in SHR from the age of 3 weeks (P<0.05). MDA levels were only significantly higher at 16 weeks of age in the SHR (P<0.05). The data suggest that altered renal CAT and GPx mRNA expression and activity precede the development of hypertension in SHR. The raised CAT activity perhaps contributes to the higher TAS and lower H2O2 levels in SHR. In view of these findings, the precise role of oxidative stress in the pathogenesis of hypertension in SHR needs to be investigated further.
    Matched MeSH terms: Blood Pressure/physiology
  2. Ariffin F, Isa MR, Nafiza MN, Mazapuspavina MY, Fadhlina AM, Palafox B, et al.
    Med J Malaysia, 2022 Sep;77(5):542-551.
    PMID: 36169064
    INTRODUCTION: Achieving optimal control of blood pressure is easier when those affected understand the risks and consequences of hypertension and the principles of management. It is particularly important in disadvantaged groups among whom blood pressure control is often poor. However, effective responses require evidence of the knowledge and beliefs of those affected. This was undertaken as part of a larger study of the therapeutic journeys followed by individuals living in B40 (bottom 40% by income) households in Malaysia, the Responsive and Equitable Health Systems-Partnership on Non- Communicable Diseases (RESPOND).This paper describes their reported knowledge of hypertension, health, and measures that can improve hypertensive control.

    MATERIALS AND METHODS: The communities were selected from rural and urban populations in four peninsular states (Selangor, Kelantan, Perak, and Johor). Following a multistage sampling approach, communities in each stratum were selected according to probability proportional to the size and identified based on national census data by the community and administrative registers. Households were randomly selected. Eligible individuals were those aged between 35 and 70 years old, self-reported or identified as hypertensive at screening. Informed consent was taken. A survey using validated questionnaires was conducted.

    RESULTS: The total number of respondents was 579. The mean age was 59.0 (95%: 58.4, 59.7) and more were women (71.5%) than men (28.5%). Regarding respondents selfreported level of hypertension knowledge, 2.9% reported having no knowledge at all, 80.1% had little knowledge, and 17.9% were very familiar. Among all respondents, 56.2% (95% CI: 50.7, 61.6) correctly answered at least four out of five objective knowledge questions.Almost all (91.5%) were aware that hypertension could cause a stroke. However, one-fifth believed it could cause cancer. Almost threequarters said that people with high blood pressure generally felt well (72.1%) and recognized that they should not stop taking their medication (70.7%). Most of the respondents knew that people should take their medication even if they feel well (73.6%). Although more than half (66.0%) of the respondents rated their health as poor. Interestingly, most did not perceive themselves as having a long-term illness (95.0%).

    CONCLUSION: This study provides reassurance that individuals with hypertension in disadvantaged communities in Malaysia have a relatively good understanding of hypertension. Further research should explore the challenges they face on their therapeutic journeys.

    Matched MeSH terms: Blood Pressure/physiology
  3. Ho BK, Omar MA, Sooryanarayana R, Ghazali SS, Zainal Abidin SBI, Krishnapillai A, et al.
    PLoS One, 2020;15(9):e0238780.
    PMID: 32911521 DOI: 10.1371/journal.pone.0238780
    BACKGROUND: Hypertension is one of the most important risk factors for cardiovascular diseases. Thus, it is an important public health challenge worldwide. In Malaysia, only a few studies have focused on the trends of hypertension specifically for the aging population. In view of the rapid growth of the elderly population in Malaysia, there is an urgent need to explore the condition of hypertension in this aging population. Hence, the objectives of this study were to determine the trends of population mean systolic and diastolic blood pressure (BP) levels, the prevalence, awareness, treatment and control of hypertension, and its' associated factors among older persons in two cross-sectional national surveys that were conducted in 2006 and 2015 in Malaysia.

    METHODS: This was a subanalysis of secondary data collected from the two cross-sectional national population-based surveys conducted in Malaysia in 2006 and 2015. Adults aged 60 and older who had participated in these two surveys were included in the study.

    RESULTS: A total of 4954 (2295 males and 2659 females) and 3790 (1771 males and 2019 females) respondents completed the hypertension module surveys in 2006 and 2015, respectively. The mean age of the respondents was 68.5±6.9 years in 2006 and 68.6±7.1 years in 2015 and the difference was not significant. The prevalence of hypertension significantly reduced from 73.8% in 2006 to 69.2% in 2015 (p<0.001). Among the respondents with hypertension, the awareness, treatment and control of hypertension significantly increased from 49.7% to 60.2%, 86.7% to 91.5% and 23.3% to 44.8%, respectively, from 2006 to 2015. Logistic regression analysis showed that female sex and unemployed/retiree were significantly associated with higher hypertension prevalence in both 2006 and 2015. Being unemployed/ retiree was significantly associated with higher awareness of hypertension in both 2006 and 2015. In both 2006 and 2015, Chinese ethnicity were significantly associated with higher awareness and control of hypertension.

    CONCLUSIONS: The mean population BP levels and hypertension prevalence among the elderly population in Malaysia have reduced significantly over the past decade. Although the awareness, treatment and control of hypertension among older adults have improved significantly, the awareness and control rates remain suboptimal. As population aging is inevitable, appropriate public health programs and optimal treatment strategies targeting this vulnerable group are urgently needed to improve the overall awareness and control of hypertension and to prevent hypertension-related complications.

    Matched MeSH terms: Blood Pressure/physiology
  4. Huang HC, Cheng HM, Chia YC, Li Y, Van Minh H, Siddique S, et al.
    J Clin Hypertens (Greenwich), 2022 Sep;24(9):1187-1193.
    PMID: 36196464 DOI: 10.1111/jch.14554
    Recent trials have demonstrated the efficacy and safety of percutaneous renal sympathetic denervation (RDN) for blood pressure (BP)-lowering in patients with uncontrolled hypertension. Nevertheless, major challenges exist, such as the wide variation of BP-lowering responses following RDN (from strong response to no response) and lack of feasible and reproducible peri-procedural predictors for patient response. Both animal and human studies have demonstrated different patterns of BP responses following renal nerve stimulation (RNS), possibly related to varied regional proportions of sympathetic and parasympathetic nerve tissues along the renal arteries. Animal studies of RNS have shown that rapid electrical stimulation of the renal arteries caused renal artery vasoconstriction and increased norepinephrine secretion with a concomitant increase in BP, and the responses were attenuated after RDN. Moreover, selective RDN at sites with strong RNS-induced BP increases led to a more efficient BP-lowering effect. In human, when RNS was performed before and after RDN, blunted changes in RNS-induced BP responses were noted after RDN. The systolic BP response induced by RNS before RDN and blunted systolic BP response to RNS after RDN, at the site with maximal RNS-induced systolic BP response before RDN, both correlated with the 24-h ambulatory BP reductions 3-12 months following RDN. In summary, RNS-induced BP changes, before and after RDN, could be used to assess the immediate effect of RDN and predict BP reductions months following RDN. More comprehensive, large-scale and long term trials are needed to verify these findings.
    Matched MeSH terms: Blood Pressure/physiology
  5. Enkelmann HC, Bishop GD, Tong EM, Diong SM, Why YP, Khader M, et al.
    Int J Psychophysiol, 2005 May;56(2):185-97.
    PMID: 15804452
    This study tested the hypotheses that ambulatory heart rate and blood pressure would be higher for individuals high but not low in hostility when they experienced negative affect or social stress and that this interaction would be stronger for Indians compared with other Singapore ethnic groups. Ambulatory blood pressure monitoring was done on 108 male Singapore patrol officers as they went about their daily duties. After each BP measurement participants completed a computerized questionnaire including items on emotional experience. Individuals high in hostility showed higher systolic blood pressure when reporting negative affect whereas this was not true for those low in hostility. Ethnic differences were obtained such that Indians showed an increase in mean arterial pressure when angered whereas MAP was negatively related to anger for Malays and unrelated for Chinese. Also a three-way interaction between ethnicity, hostility, and social stress indicated that hostility and social stress interacted in their effects on DBP for Indian participants but not for Chinese or Malays. Finally, a three-way interaction was obtained between ethnicity, hostility and negative affect for heart rate in which heart rate increased with increasing levels of negative affect for Chinese high in hostility and Malays low in hostility but decreased with increasing negative affect for all other participants. These data are consistent with higher CHD rates among individuals high in hostility and also provide additional evidence on ethnic differences in cardiovascular reactivity in Singapore.
    Matched MeSH terms: Blood Pressure/physiology
  6. Nasir NF, Kannan TP, Sulaiman SA, Shamsuddin S, Azlina A, Stangaciu S
    Age (Dordr), 2015 Jun;37(3):9797.
    PMID: 26028466 DOI: 10.1007/s11357-015-9797-6
    The belief that beekeepers live longer than anyone else is present since ages. However, no research has been done to explore the longevity of life in beekeepers. Here, we investigated the telomere length in 30 male beekeepers and 30 male non-beekeepers and associated them with the longevity of life using Southern analysis of terminal restriction fragments (TRFs) generated by Hinf I/Rsa I digestion of human genomic DNA using TeloTAGGG Telomere Length Assay. Interestingly, we found that the telomere length of male beekeepers was significantly longer than those of male non-beekeepers with a p value of less than 0.05, suggesting that beekeepers may have longer life compared to non-beekeepers. We further found that the consumption of bee products for a long period and frequent consumption of bee products per day are associated with telomere length. An increase of year in consuming bee products is associated with a mean increase in telomere length of 0.258 kbp. In addition, an increase in frequency of eating bee products per day was also associated with a mean increase of 2.66 kbp in telomere length. These results suggested that bee products might play some roles in telomere length maintenance.
    Matched MeSH terms: Blood Pressure/physiology
  7. Abdulla MH, Sattar MA, Abdullah NA, Khan MA, Anand Swarup KR, Johns EJ
    Auton Autacoid Pharmacol, 2011 Jan-Apr;31(1-2):13-20.
    PMID: 21166975 DOI: 10.1111/j.1474-8673.2010.00461.x
    1 Interaction between renin-angiotensin (RAS) and sympathetic nervous systems (SNS) was investigated by examining the effect of cumulative blockade of angiotensin II (Ang II) and adrenergic receptors in normal Sprague Dawley rats. 2 Rats were treated with losartan (10 mg/kg), carvedilol (5 mg/kg), or losartan plus carvedilol (10+5 mg/kg) orally for 7 days. On day 8, the animals were anaesthetized with pentobarbitone and prepared for systemic haemodynamic study. Dose-response relationships for the elevation of mean arterial pressure or change in heart rate (HR) in response to intravenous injections of noradrenaline (NA), phenylephrine (PE), methoxamine (ME) and Ang II were determined. 3 Losartan or the combination of losartan with carvedilol blunted vasopressor responses to ME and Ang II. Dose-response relationships for agonist action on HR were significantly inhibited by all treatments except for the combination of losartan and carvedilol on the decrease in HR induced by PE. Carvedilol decreased vasopressor responses to NA, PE and Ang II, and HR responses to NA, ME and Ang II. Combination treatment produced similar effects to losartan on the vasopressor and HR responses but had a greater effect on vasopressor responses to ME and Ang II, and on HR responses to NA and Ang II than carvedilol alone. 4 It is concluded that peripheral vasoconstriction induced by Ang II is partly mediated by adrenergic action and that the vasopressor responses to adrenergic agonists depend on an intact RAS. These observations suggest an interactive relationship between RAS and SNS in determining systemic haemodynamic responses in 'normal' rats.
    Matched MeSH terms: Blood Pressure/physiology
  8. Rafidah HM, Azizi A, Suhaimi H, Noriah MN
    Med J Malaysia, 2008 Mar;63(1):9-16.
    PMID: 18935724 MyJurnal
    Normotensive subjects with family history of hypertension (FHT) have been reported to have increased left ventricular mass index and reduced ventricular compliance. Of interest is whether blood pressure variability (BPV), which has been associated with target organ damage, is then part of this complex inherited syndrome? The objectives of this study are to determine whether there are any significant differences in BPV, arterial compliance and humoral factors in subjects with FHT as compared to controls. Thirty-five subjects with self reported FHT and 35 matched controls underwent 24 hour BP monitoring (BR-102, Schiller Inc. Germany). Arterial compliance was measured using systolic pulse wave tonometry (HDI/Pulsewave Cardiovascular Profiling Instrument, Hypertension Diagnostic Inc. USA). None of the subjects were hypertensive or diabetic. Out of these numbers, 25 subjects with FHT and 26 controls had measurements of plasma catecholamines, plasma renin and serum aldosterone. Catecholamines were assayed with high performance liquid chromatography, while both renin and aldosterone measurements were by radioimmunoassay. Subjects with FHT have higher night time BPV. There was no significant difference in arterial compliances between both groups. There were increased level of norepinephrine (NE) in subjects with FHT but epinephrine (E), renin and aldosterone levels were similar in both groups. There were no correlations between NE and BPV but E was negatively associated with daytime and mean arterial systolic BPV. In conclusion subjects with FHT demonstrated a higher night time BPV and NE level as compared to controls.
    Matched MeSH terms: Blood Pressure/physiology*
  9. Saedon NI, Pin Tan M, Frith J
    J Gerontol A Biol Sci Med Sci, 2020 01 01;75(1):117-122.
    PMID: 30169579 DOI: 10.1093/gerona/gly188
    BACKGROUND: Orthostatic hypotension (OH) is associated with increased risk of falls, cognitive impairment and death, as well as a reduced quality of life. Although it is presumed to be common in older people, estimates of its prevalence vary widely. This study aims to address this by pooling the results of epidemiological studies.

    METHODS: MEDLINE, EMBASE, PubMed, Web of Science, and ProQuest were searched. Studies were included if participants were more than 60 years, were set within the community or within long-term care and diagnosis was based on a postural drop in systolic blood pressure (BP) ≥20 mmHg or diastolic BP ≥10 mmHg. Data were extracted independently by two reviewers. Random and quality effects models were used for pooled analysis.

    RESULTS: Of 23,090 identified records, 20 studies were included for community-dwelling older people (n = 24,967) and six were included for older people in long-term settings (n = 2,694). There was substantial variation in methods used to identify OH with differing supine rest duration, frequency and timing of standing BP, measurement device, use of standing and tilt-tables and interpretation of the diagnostic drop in BP. The pooled prevalence of OH in community-dwelling older people was 22.2% (95% CI = 17, 28) and 23.9% (95% CI = 18.2, 30.1) in long-term settings. There was significant heterogeneity in both pooled results (I2 > 90%).

    CONCLUSIONS: OH is very common, affecting one in five community-dwelling older people and almost one in four older people in long-term care. There is great variability in methods used to identify OH.

    Matched MeSH terms: Blood Pressure/physiology*
  10. Kario K, Wang JG, Chia YC, Wang TD, Li Y, Siddique S, et al.
    J Clin Hypertens (Greenwich), 2022 Sep;24(9):1112-1120.
    PMID: 36196465 DOI: 10.1111/jch.14555
    Morning hypertension is an important clinical target in the management of hypertension for perfect 24-h blood pressure (BP) control. Morning hypertension is generally categorized into two types: "morning surge" type and "sustained nocturnal and morning hypertension" type. The "morning surge" type is characterized by an exaggerated morning blood pressure surge (MBPS), and the "sustained nocturnal and morning hypertension" type with continuous hypertension from nighttime to morning (non-dipper/riser type). They can be detected by home and ambulatory blood pressure measurements (HBPM and ABPM). These two forms of morning hypertension both increase the risk of cardiovascular and renal diseases, but may occur via different pathogenic mechanisms and are associated with different conditions. Morning hypertension should be treated to achieve a morning BP level of 
    Matched MeSH terms: Blood Pressure/physiology
  11. Wong SK, Chin KY, Suhaimi FH, Ahmad F, Ima-Nirwana S
    Exp. Clin. Endocrinol. Diabetes, 2018 Apr;126(4):205-212.
    PMID: 29117620 DOI: 10.1055/s-0043-119352
    Metabolic syndrome is a cluster of metabolic abnormalities including central obesity, hyperglycemia, hypertension, and dyslipidemia. A previous study has established that high-carbohydrate high-fat diet (HCHF) can induce MetS in rats. In this study, we modified components of the diet so that it resembled the diet of Southeast Asians. This study aimed to determine the effects of this modified HCHF diet on metabolic parameters in rats. Male Wistar rats (n=14) were randomised into two groups. The normal group was given standard rat chow. The MetS group was given the HCHF diet, comprises of fructose, sweetened condensed milk, ghee, Hubble Mendel and Wakeman salt mixture, and powdered rat food. The diet regimen was assigned for a period of 16 weeks. Metabolic syndrome parameters (abdominal circumference, blood glucose, blood pressure, and lipid profile) were measured at week 0, 8, 12, and 16 of the study. The measurement of whole body composition (fat mass, lean mass, and percentage of fat) was performed using dual-energy X-ray absorptiometry at week 0, 8, and 16. Our results indicated that the components of MetS were partially developed after 8 weeks of HCHF diet. Systolic blood pressure, triglyceride, low density lipoprotein cholesterol, fat content, and percentage of fat was significantly higher in the HCHF group compared to normal group (p<0.05). After 12 weeks of HCHF diet, the rats showed significant increases in abdominal circumference, blood pressure, glucose intolerance, and dyslipidemia compared to normal control (p<0.05). In conclusion, MetS is successfully established in male rats induced by the modified HCHF diet after 12 weeks.
    Matched MeSH terms: Blood Pressure/physiology*
  12. Tan MP, Chadwick TJ, Kerr SR, Parry SW
    J Am Heart Assoc, 2014 Jun;3(3):e000514.
    PMID: 24947997 DOI: 10.1161/JAHA.113.000514
    Carotid sinus hypersensitivity (CSH) is associated with syncope, unexplained falls, and drop attacks in older people but occurs asymptomatically in 35% of community-dwelling elders. We hypothesized that impaired cerebral autoregulation is associated with the conversion of asymptomatic CSH to symptomatic CSH. We therefore conducted a case-control study evaluating individuals with CSH with and without the symptoms of syncope or unexplained falls, as well as non-CSH controls, to determine whether the blood pressure and heart rate changes associated with CSH are associated with symptoms only when cerebral autoregulation is altered.
    Matched MeSH terms: Blood Pressure/physiology
  13. Sharudin SN, Saaid R, Samsudin A, Mohamad NF
    Optom Vis Sci, 2020 02;97(2):81-85.
    PMID: 32011579 DOI: 10.1097/OPX.0000000000001480
    SIGNIFICANCE: To our knowledge, this is the first time a study looking at the association between subfoveal choroidal thickness (SFCT) and the parameters affecting the severity of pre-eclampsia has been reported. We provide evidence that SFCT is thicker in pre-eclamptic (PE) patients and speculate on the possible causes.

    PURPOSE: The purposes of this study were to compare SFCT in PE, normal pregnant, and nonpregnant women using spectral domain optical coherence tomography and to correlate SFCT with severity of pre-eclampsia.

    METHODS: A cross-sectional, observational study was performed. A total of 150 participants were divided into three groups: group 1 (50 PE women), group 2 (50 normal pregnant women), and group 3 (50 nonpregnant healthy women). Subfoveal choroidal thickness was measured using spectral domain optical coherence tomography. Other parameters including mean arterial blood pressure (MABP), central corneal thickness, macular thickness, IOP, ocular perfusion pressure (OPP), and urine protein-to-creatinine ratio were also measured. ANOVA and Pearson correlation analysis were used to look at differences between the groups. P < .05 was considered as statistically significant.

    RESULTS: The MABP was higher in group 1 than in groups 2 and 3 (103.0 ± 12.9 vs. 83.2 ± 9.8 vs. 89.5 ± 7.2 mmHg, respectively; all P < .001). The SFCT of the PE group was higher than in groups 2 and 3 (370.7 ± 23.8 vs. 344.5 ± 30.8 vs. 315.8 ± 49.9 μm, respectively; all P < .001). There were no statistically significant differences in central corneal thickness, macular thickness, or IOP between the PE and healthy pregnant groups (all P > .05). The OPP was greater in PE patients (52.8 ± 8.5 vs. 41.9 ± 6.9 vs. 43.4 ± 5.2 mmHg, respectively; both P < .001). The SFCT was positively correlated with MABP (r = 0.464, P < .001), OPP (r = 0.495, P < .001), and urine protein-to-creatinine ratio (r = 0.635, P < .001) in the PE group.

    CONCLUSIONS: Subfoveal choroidal thickness is higher in pre-eclampsia and is proportional to established markers of severity of the condition. This parameter might serve as a novel predictive marker for the severity of pre-eclampsia.

    Matched MeSH terms: Blood Pressure/physiology
  14. Goh CH, Ng SC, Kamaruzzaman SB, Chin AV, Tan MP
    Medicine (Baltimore), 2017 Oct;96(42):e8193.
    PMID: 29049203 DOI: 10.1097/MD.0000000000008193
    The aim of this study was to determine the relationship between falls and beat-to-beat blood pressure (BP) variability.Continuous noninvasive BP measurement is as accurate as invasive techniques. We evaluated beat-to-beat supine and standing BP variability (BPV) using time and frequency domain analysis from noninvasive continuous BP recordings.A total of 1218 older adults were selected. Continuous BP recordings obtained were analyzed to determine standard deviation (SD) and root mean square of real variability (RMSRV) for time domain BPV and fast-Fourier transform low frequency (LF), high frequency (HF), total power spectral density (PSD), and LF:HF ratio for frequency domain BPV.Comparisons were performed between 256 (21%) individuals with at least 1 fall in the past 12 months and nonfallers. Fallers were significantly older (P = .007), more likely to be female (P = .006), and required a longer time to complete the Timed-Up and Go test (TUG) and frailty walk test (P ≤ .001). Standing systolic BPV (SBPV) was significantly lower in fallers compared to nonfallers (SBPV-SD, P = .016; SBPV-RMSRV, P = .033; SBPV-LF, P = .003; SBPV-total PSD, P = .012). Nonfallers had significantly higher supine to standing ratio (SSR) for SBPV-SD, SBPV-RMSRV, and SBPV-total PSD (P = .017, P = .013, and P = .009). In multivariate analyses, standing BPV remained significantly lower in fallers compared to nonfallers after adjustment for age, sex, diabetes, frailty walk, and supine systolic BP. The reduction in frequency-domain SSR among fallers was attenuated by supine systolic BP, TUG, and frailty walk.In conclusion, reduced beat-to-beat BPV while standing is independently associated with increased risk of falls. Changes between supine and standing BPV are confounded by supine BP and walking speed.
    Matched MeSH terms: Blood Pressure/physiology*
  15. Teoh AN, Hilmert C
    Br J Health Psychol, 2018 11;23(4):1040-1065.
    PMID: 30084181 DOI: 10.1111/bjhp.12337
    PURPOSE: The stress-buffering hypothesis (Cohen & McKay, 1984, Handbook of psychology and health IV: Social psychological aspects of health (pp. 253-256). Hillsdale, NJ: Lawrence Erlbaum) suggests that one way social support enhances health is by attenuating cardiovascular reactivity (CVR) to stress. Research that has tested this hypothesis has reported inconsistent findings. In this review, we systematically reviewed those findings and proposed a dual-effect model of social support and CVR as a potential explanation for the inconsistency in the literature. Specifically, we proposed that when participants are more engaged during a stressor, social support acts primarily as social comfort, attenuating CVR; and when participants are not engaged, social support acts primarily as social encouragement, elevating CVR.

    METHODS: We reviewed 22 previous studies that (1) empirically manipulated social support in a stressful situation, (2) measured CVR, and (3) tested a moderator of social support effects on CVR.

    RESULTS: Although a majority of studies reported a CVR-mitigating effect of social support resulting in an overall significant combined p-value, we found that there were different effects of social support on CVR when we considered high- and low-engagement contexts. That is, compared to control conditions, social support lowered CVR in more engaging situations but had no significant effect on CVR in less engaging situations.

    CONCLUSION: Our results suggest that a dual-effect model of social support effects on CVR may better capture the nature of social support, CVR, and health associations than the buffering hypothesis and emphasize a need to better understand the health implications of physiological reactivity in various contexts. Statement of contribution What is already known on this subject? According to the stress-buffering hypothesis (Cohen & McKay, ), one pathway social support benefits health is through mitigating the physiological arousal caused by stress. However, previous studies that examined the effects of social support on blood pressure and heart rate changes were not consistently supporting the hypothesis. Some studies reported that social support causes elevations in cardiovascular reactivity (CVR) to stress (Anthony & O'Brien, ; Hilmert, Christenfeld, & Kulik, ; Hilmert, Kulik, & Christenfeld, ) and others showed no effect of social support on CVR (Christian & Stoney, ; Craig & Deichert, ; Gallo, Smith, & Kircher, ). What does this study add? When participants were in more engaging conditions, social support decreased CVR relative to no support. When participants were in less engaging conditions, social support did not have a significant effect on CVR. Provide an alternative way to explain the ways social support affects cardiac health.

    Matched MeSH terms: Blood Pressure/physiology*
  16. Yusof AP, Yusoff NH, Suhaimi FW, Coote JH
    Auton Neurosci, 2009 Jun 15;148(1-2):50-4.
    PMID: 19349212 DOI: 10.1016/j.autneu.2009.03.005
    The aim of the present study was to determine if paraventricular-spinal vasopressin neurones participate in the sympatho-inhibitory effects of systemically administered atrial natriuretic peptide (ANP) on renal sympathetic nerve activity (RSNA). Experiments were carried out on male Sprague-Dawley rats anesthetized with 1.3 g/kg urethane. Changes in mean arterial pressure (mm Hg), heart rate (beats per minute) and RSNA (%) were measured following intravenous bolus administration of ANP (250 ng, 500 ng and 5 microg). Intrathecal application of selective V 1a receptor antagonist was performed to test for the involvement of supraspinal vasopressin pathways in mediating the effect on sympathetic outflow evoked by intravenous ANP administration. The results obtained demonstrated that both low and high doses of ANP caused renal sympathoinhibition (250 ng; - 7.5 +/- 1%, 500 ng; - 14.2 +/- 1%, 5 microg; - 16.4 +/- 2%), concomitant with vasodilation and bradycardia. After spinal vasopressin receptor blockade, the inhibitory effects of ANP were prevented and there was a small renal sympatho-excitation (250 ng; + 1.7 +/- 0.2%, 500 ng; + 6.1 +/- 0.03%, 5 microg; + 8.0 +/- 0.03%, P < 0.05). Therefore, the renal sympathetic nerve inhibition elicited by circulating ANP is dependent on the efficacy of a well established supraspinal vasopressin pathway. Since supraspinal vasopressin neurones without exception excite renal sympathetic neurones, it is suggested that ANP elicits this effect by activating cardiac vagal afferents that inhibit the spinally projecting vasopressin neurones at their origin in the paraventricular nucleus of the hypothalamus.
    Matched MeSH terms: Blood Pressure/physiology
  17. Suhaimi FW, Yusoff NH, Dewa A, Yusof AP
    Acta Neurol Belg, 2010 Mar;110(1):57-64.
    PMID: 20514927
    Obesity is intimately associated with hypertension; increases in blood pressure are closely related to the magnitude of weight gain. The present study aims to determine whether the excitatory amino acid input to rostral ventrolateral medulla (RVLM) contributes to elevated blood pressure in rats with diet-induced obesity. Male Sprague-Dawley rats weighing 280 to 300 grams were fed with a low-fat diet (10% kcal from fat) or moderately high-fat diet (32% kcal from fat) for 16 weeks. At week 16, rats on the moderate high-fat diet were segregated into obesity-prone and obesity-resistant rats based on body weight distribution. Baseline mean arterial pressure (MAP) was significantly higher in obesity-prone rats as compared to obesity-resistant and rats on a low-fat diet. Bilateral injection of kynurenic acid (KYN) (40 nM) into the RVLM of the obesity-prone rats reduced MAP to levels significantly different from those observed in rats on a low-fat diet and obesity-resistant rats (no change in MAP). At a lower concentration (4 nM), KYN injection did not produce any change in MAP in any group. The results obtained suggest that excitatory amino acid input to the RVLM does contribute to the development of hypertension in rats with diet-induced obesity.
    Matched MeSH terms: Blood Pressure/physiology
  18. Kario K, Kim BK, Aoki J, Wong AY, Lee YH, Wongpraparut N, et al.
    Hypertension, 2020 Mar;75(3):590-602.
    PMID: 32008432 DOI: 10.1161/HYPERTENSIONAHA.119.13671
    The Asia Renal Denervation Consortium consensus conference of Asian physicians actively performing renal denervation (RDN) was recently convened to share up-to-date information and regional perspectives, with the goal of consensus on RDN in Asia. First- and second-generation trials of RDN have demonstrated the efficacy and safety of this treatment modality for lowering blood pressure in patients with resistant hypertension. Considering the ethnic differences of the hypertension profile and demographics of cardiovascular disease demonstrated in the SYMPLICITY HTN (Renal Denervation in Patients With Uncontrolled Hypertension)-Japan study and Global SYMPLICITY registry data from Korea and Taiwan, RDN might be an effective hypertension management strategy in Asia. Patient preference for device-based therapy should be considered as part of a shared patient-physician decision process. A practical population for RDN treatment could consist of Asian patients with uncontrolled essential hypertension, including resistant hypertension. Opportunities to refine the procedure, expand the therapy to other sympathetically mediated diseases, and explore the specific effects on nocturnal and morning hypertension offer a promising future for RDN. Based on available evidence, RDN should not be considered a therapy of last resort but as an initial therapy option that may be applied alone or as a complementary therapy to antihypertensive medication.
    Matched MeSH terms: Blood Pressure/physiology
  19. Schwalm JR, McCready T, Lamelas P, Musa H, Lopez-Jaramillo P, Yusoff K, et al.
    Am Heart J, 2018 09;203:57-66.
    PMID: 30015069 DOI: 10.1016/j.ahj.2018.06.004
    BACKGROUND: Cardiovascular disease is the leading cause of death throughout the world, with the majority of deaths occurring in low- and middle-income countries. Despite clear evidence for the benefits of blood pressure reduction and availability of safe and low-cost medications, most individuals are either unaware of their condition or not adequately treated.

    OBJECTIVE: The primary objective of this study is to evaluate whether a community-based, multifaceted intervention package primarily provided by nonphysician health workers can improve long-term cardiovascular risk in people with hypertension by addressing identified barriers at the patient, health care provider, and health system levels.

    METHODS/DESIGN: HOPE-4 is a community-based, parallel-group, cluster randomized controlled trial involving 30 communities (1,376 participants) in Colombia and Malaysia. Participants ≥50 years old and with newly diagnosed or poorly controlled hypertension were included. Communities were randomized to usual care or to a multifaceted intervention package that entails (1) detection, treatment, and control of cardiovascular risk factors by nonphysician health workers in the community, who use tablet-based simplified management algorithms, decision support, and counseling programs; (2) free dispensation of combination antihypertensive and cholesterol-lowering medications, supervised by local physicians; and (3) support from a participant-nominated treatment supporter (either a friend or family member). The primary outcome is the change in Framingham Risk Score after 12 months between the intervention and control communities. Secondary outcomes including change in blood pressure, lipid levels, and Interheart Risk Score will be evaluated.

    SIGNIFICANCE: If successful, the study could serve as a model to develop low-cost, effective, and scalable strategies to reduce cardiovascular risk in people with hypertension.

    Matched MeSH terms: Blood Pressure/physiology*
  20. Yeo JJP, Yeo LS, Tan SSN, Delailah DDRA, Lee SWH, Hu ATH, et al.
    Hypertens Res, 2024 Feb;47(2):352-357.
    PMID: 37673957 DOI: 10.1038/s41440-023-01418-4
    Resistant hypertension is a well-recognised clinical challenge. However, the definition and epidemiology of true resistant hypertension (RH) are less understood, especially in Asia. This cross-sectional study examined the prevalence of RH referred from primary care clinics based on various guidelines. RH was defined as blood pressure (BP) being above the threshold using ambulatory blood pressure monitoring despite adequate lifestyle measures and optimal treatment with ≥3 medications at maximally tolerated doses. Between one in four (n = 94, 24.0% using Malaysian guidelines) and up to two-thirds (n = 249, 63.7% using 2018 American guidelines) of adults referred for uncontrolled hypertension met the criteria of true RH. Of those with RH, a further one-quarter (n = 26, 26.6%) were deemed to have refractory hypertension (elevated BP despite treatment with at least 5 antihypertensive medications). Adults with RH were generally younger, more likely to be male, had a higher BMI and were more likely to have gout, CKD, and angina compared to those with controlled hypertension. The prevalence of RH amongst Asian adults with poor hypertension control is high. A concerted effort is needed to reduce the high burden of RH, especially among this population.
    Matched MeSH terms: Blood Pressure/physiology
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