Displaying publications 41 - 60 of 262 in total

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  1. Nikol L, Kuan G, Ong M, Chang YK, Terry PC
    Front Psychol, 2018;9:1114.
    PMID: 30072929 DOI: 10.3389/fpsyg.2018.01114
    Running in high heat and humidity increases psychophysiological strain, which typically impairs running performance. Listening to synchronous music has been shown to provide psychophysiological benefits, which may enhance running performance. The present randomized, crossover study examined effects of listening to synchronous music on psychophysiological parameters and running performance in hot and humid conditions. Twelve male runners (21.7 ± 2.2 y; 166.17 ± 7.18 cm; 60.32 ± 9.52 kg; 59.29 ± 5.95 ml kg-1 min-1) completed two running trials in simulated conditions (31°C and 70% humidity) with and without synchronous music. Participants ran on a treadmill inside a climatic chamber for 60 min at 60%

    V
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    O2max and continued to run to exhaustion at 80%

    V
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    O2max. Time-to-exhaustion under the synchronous music condition was 66.59% longer (mean = 376.5 s vs. 226.0 s, p = 0.02, d = 0.63) compared to the no music condition. Ratings of perceived exertion were significantly lower for the synchronous music condition at each time point (15, 30, 45, and 60 min) of the steady state portion of the running trials. Small differences in heart rate were detected between conditions. No significant between-condition differences were found in urine specific gravity, percentage of body weight loss, thermal comfort, and blood lactate. Findings suggest that listening to synchronous music is beneficial to running performance and perceived exertion in hot and humid conditions.
    Matched MeSH terms: Heart Rate
  2. Abbasi H, Saqib M, Jouhar R, Lal A, Ahmed N, Ahmed MA, et al.
    Biomed Res Int, 2021;2021:1119710.
    PMID: 34124238 DOI: 10.1155/2021/1119710
    Introduction: Dental anxiety is a common occurrence in patients undergoing dental treatments, especially in children. The success in paedriatric dental treatments and patient comfort depends on controlling the level of patient's anxiety in clinical settings. This study is aimed at evaluating the efficacy of different techniques applied for the reduction of dental anxiety in paediatric patients. Material and Methods. One hundred and sixty participants were divided into 4 groups; each group having 40 patients as follows: group I: mobile application "little lovely dentist," group II: YouTube® "dental video songs," group III "tell-show-do," and group IV "control." Dental prophylaxis treatments were provided to all the participants. Initial anxiety levels were noted during the patient's education phase by measuring heart rate with pulse oximeter and distress level with facial image scale, at the same time in each group, respectively. The postoperative anxiety was noted later with the same methods, after the application of anxiety reduction techniques. The data obtained were entered in the statistical package for the social sciences software, version 25. One-way ANOVA and paired t-test for matched groups were used to compare mean values of the 4 groups, in this study to determine their effectiveness. A p value of ≤0.05 was considered as statistically significant.

    Results: The mean age of patients in group 1 was 6.8 ± 2.1 years, group 2: 8.15 ± 2.27 years, group 3: 7.5 ± 2.3 years, and group 4: 7.27 ± 1.68 years. The intragroup comparisons of heart rate and facial image scores have shown a significant difference in before and after dental treatment procedures. Marked reduction in heart rate and facial image scale scores were found in patients belonging to group 1 (mobile applications) and group 2 (dental video songs). An increase in heart rate and facial image scale scores was seen in group 3 (tell-show-do) and the control group.

    Conclusion: The paediatric dental anxiety is a common finding in dental clinics. Behavior modification techniques like smartphone applications, "little lovely dentist," and "dental songs" can alleviate dental anxiety experienced by paediatric patients. The "tell-show-do" technique although most commonly used did not prove to be beneficial in the reduction of the anxiety levels.

    Matched MeSH terms: Heart Rate
  3. Ezema CI, Omeh E, Onyeso OKK, Anyachukwu CC, Nwankwo MJ, Amaeze A, et al.
    Malays J Med Sci, 2019 Sep;26(5):88-97.
    PMID: 31728121 DOI: 10.21315/mjms2019.26.5.8
    Background: Diabetes mellitus increases the risk of cardiovascular diseases and all-cause mortality. The present study investigated the effect of an eight-week aerobics programme on fasting blood sugar (FBS), cardiovascular parameters, peripheral oxygen saturation (SpO2), and body mass index (BMI) among subjects with type-2 diabetes mellitus (T2DM).

    Methods: A pretest-posttest experimental design was employed. Fifty subjects, diagnosed with T2DM, attending the Diabetes Clinic of the University of Nigeria Teaching Hospital, Enugu, were conveniently recruited, gender and age-matched, and randomised into exercise and control groups. The intervention included an eight-week aerobic exercise at 60%-79% HRmax for 45 min-60 min, 3-days per week. The FBS, SpO2, BMI, resting heart rate (RHR), and systolic (SBP) and diastolic blood pressure (DBP) of the subjects were measured before and after the intervention. The paired and independent t-test(s) were used for the analyses within and between the groups, respectively (P ≤ 0.05).

    Results: The exercise group had a significantly lower SBP (15.0 mmHg, P = 0.001), DBP (7.9 mmHg, P = 0.001), RHR (4.8 bpm, P = 0.001), FBS (34.9 mg/dl, P = 0.001), and BMI (2.3, P = 0.001), while the SpO2 improved by 3.9% with P = 0.001, relative to the control group.

    Conclusion: Aerobics is an efficacious adjunct therapy in controlling the FBS level, blood pressure, BMI, and improving SpO2 among T2DM subjects.

    Matched MeSH terms: Heart Rate
  4. Ng CG, Lai KT, Tan SB, Sulaiman AH, Zainal NZ
    J Palliat Med, 2016 09;19(9):917-24.
    PMID: 27110900 DOI: 10.1089/jpm.2016.0046
    BACKGROUND: Palliative cancer patients suffer from high levels of distress. There are physiological changes in relation to the level of perceived distress.

    OBJECTIVE: To study the efficacy of 5 minutes of mindful breathing (MB) for rapid reduction of distress in a palliative setting. Its effect to the physiological changes of the palliative cancer patients was also examined.

    METHODS: This is a randomized controlled trial. Sixty palliative cancer patients were recruited. They were randomly assigned to either 5 minutes of MB or normal listening arms. The changes of perceived distress, blood pressure, pulse rate, breathing rate, galvanic skin response, and skin surface temperature of the patients were measured at baseline, after intervention, and 10 minutes post-intervention.

    RESULTS: There was significant reduction of perceived distress, blood pressure, pulse rate, breathing rate, and galvanic skin response; also, significant increment of skin surface temperature in the 5-minute MB group. The changes in the 5-minute breathing group were significantly higher than the normal listening group.

    CONCLUSION: Five-minute MB is a quick, easy to administer, and effective therapy for rapid reduction of distress in palliative setting. There is a need for future study to establish the long-term efficacy of the therapy.

    Matched MeSH terms: Heart Rate
  5. Sarkar P, Lite C, Kumar P, Pasupuleti M, Saraswathi NT, Arasu MV, et al.
    Int J Biol Macromol, 2020 Oct 31.
    PMID: 33137391 DOI: 10.1016/j.ijbiomac.2020.10.222
    The antioxidant role of sulfite reductase (SiR) derived from Arthrospira platensis (Ap) was identified through a short peptide, TL15. The study showed that the expression of ApSiR was highly expressed on day ten due to sulfur deprived stress in Ap culture. TL15 peptide exhibited strong antioxidant activity when evaluated using antioxidant assays in a concentration ranging from 7.8 and 125 μM. Further, the cytotoxicity of TL15 peptide was investigated, even at the higher concentration (250 μM), TL15 did not exhibit any toxicity, when tested in vitro using human leucocytes. Moreover, a potential reduction in reactive oxygen species (ROS) production was observed due to the treatment of TL15 peptide (>15.6 μM) to H2O2 exposed leucocytes. For the in vivo assessment of TL15 toxicity and antioxidant ability, experiments were performed in zebrafish (Danio rerio) larvae to analyse the developmental toxicity of TL15 peptide. Results showed that, exposure to TL15 peptide in tested concentrations ranging from 10, 20, 40, and 80 μM, did not affect the development and physiological parameters of the zebrafish embryo/larvae such as morphology, survival, hatching and heart rate. Fluorescent assay was performed using DCFH-DA (2,7-dichlorodihydrofluorescein diacetate) to examine the production of intracellular reactive oxygen species (ROS) in zebrafish treated with TL15 peptide during the embryo-larval stages. Fluorescent images showed that pre-treatment with TL15 peptide to attenuate the H2O2 induced ROS levels in the zebrafish larvae in a dose-dependent manner. Further to uncover the underlying biochemical and antioxidant mechanism, the enzyme activity of superoxide dismutase (SOD), catalase (CAT) and lipid peroxidation (LPO) levels were studied in zebrafish larvae. TL15 pre-treated groups showed enhanced antioxidant enzyme activity, while the hydrogen peroxide (H2O2) exposed larvae showed significantly diminished activity. Overall results from the study revealed that, TL15 act as a potential antioxidant molecule with dose-specific antioxidant property. Thus, TL15 peptide could be an effective and promising source for biopharmaceutical applications.
    Matched MeSH terms: Heart Rate
  6. Siew KSW, Tan MP, Hilmi IN, Loch A
    BMC Cardiovasc Disord, 2019 08 07;19(1):191.
    PMID: 31391000 DOI: 10.1186/s12872-019-1174-4
    BACKGROUND: Swallow or deglutition syncope is an unusual type of neurally-mediated syncope associated with life-threatening bradyarrhythmia and hypotension. It is a difficult condition to diagnose with commonly delayed diagnosis and management. There is lack of review articles that elucidate the basic demographics, clinical characteristics and management of this rare condition. This publication systematically reviews the 101 case reports published since 1793 on swallow syncope.

    CASE PRESENTATION: A 59-year-old man presented with the complaint of recurrent dizziness associated with meals. A 24-h ambulatory ECG recording confirmed an episode of p-wave asystole at the time of food intake. Oesophagogastroduodenoscopy with balloon inflation in the mid to lower oesophagus resulted in a 5.6 s sinus pause. The patient's symptoms resolved completely following insertion of a permanent dual chamber pacemaker.

    CONCLUSIONS: Swallow syncope is extremely rare, but still needs to be considered during diagnostic workup. It is commonly associated with gastro-intestinal disease. Permanent pacemaker implantation is the first line treatment.

    Matched MeSH terms: Heart Rate
  7. Sharma JN, Amrah SS, Noor AR
    Pharmacology, 1995 Jun;50(6):363-9.
    PMID: 7568335
    The present investigation evaluated the effects of aprotinin, an inhibitor of kallikrein, on blood pressure responses, heart rate, and duration of hypotension induced by acute administration of captopril and enalapril (angiotensin-converting enzyme inhibitors) in anaesthetized spontaneously hypertensive rats. Captopril (20 mg/kg) and enalapril (20 mg/kg) administered intravenously caused a significant (p < 0.001) fall in systolic and diastolic blood pressures in the absence of aprotinin. In contrast, captopril (20 mg/kg) and enalapril (20 mg/kg) failed (p > 0.05) to cause a fall in systolic and diastolic blood pressures in the presence of aprotinin (2 mg/kg). Captopril and enalapril were able to significantly reduce the heart rate (p < 0.05 and p < 0.001) in the presence as well as in the absence of aprotinin. The duration of hypotension produced by captopril and enalapril was abolished significantly (p < 0.001) in the presence of aprotinin. These findings may suggest that captopril and enalapril caused hypotension via the kallikrein pathway, since the kallikrein inhibitor aprotinin can antagonize the hypotensive responses of these agents. Thus, kallikrein may be an independent mediator in the regulation of blood pressure.
    Matched MeSH terms: Heart Rate/drug effects
  8. Boon CM, Ng MH, Choo YM, Mok SL
    PLoS One, 2013;8(2):e55908.
    PMID: 23409085 DOI: 10.1371/journal.pone.0055908
    Oleic acid has been shown to lower high blood pressure and provide cardiovascular protection. Curiosity arises as to whether super olein (SO), red palm olein (RPO) and palm olein (PO), which have high oleic acid content, are able to prevent the development of hypertension.
    Matched MeSH terms: Heart Rate/drug effects
  9. 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: Heart Rate/physiology
  10. Kamal MSA, Ismail NH, Satar NA, Azis NA, Radjeni Z, Mohammad Noor HS, et al.
    Clin Exp Hypertens, 2019;41(5):444-451.
    PMID: 30648895 DOI: 10.1080/10641963.2018.1506467
    Ficus deltoidea is used in Malay traditional medicine for the treatment of a number of disorders, including hypertension. There is, however, no scientific evidence on its anti-hypertensive effects. This study, therefore, investigated the effects of a standardized ethanolic-water extract of Ficus deltoidea Angustifolia (FD-A) on blood pressure (BP) in spontaneously hypertensive rats (SHR). Male SHR with systolic BP of >150 were divided into 4 groups (n = 8) and given either FD-A (800 or 1000 mg kg-1 day-1) or losartan (10 mg kg-1 day-1) or 0.5 ml of distilled water (control) daily for 28 days. BP, body weight, food and water intake, serum and urinary electrolytes, endothelin-1 (ET-1), total antioxidant capacity (TAC) and components of the renin-angiotensin-aldosterone system were measured. Data were analyzed using ANOVA with statistical significance set at p heart rate, and heart weight in FD-A and losartan-treated rats were significantly lower than those in the controls. Serum TAC and urinary calcium excretion were significantly higher, whereas serum ET-1 concentration was significantly lower in FD-A treated rats when compared to those in controls. No significant differences were found in the components of the renin-angiotensin-aldosterone system between controls and FD-A treated rats. In conclusion, FD-A when given daily at doses of either 800 or 1000 mg kg-1 day-1 body weight reduces BP in SHR. This effect does not seem to involve the renin-angiotensin-aldosterone-system but might involve some other mechanisms. Abbreviations: FD-A: Ficus deltoidea Angustifolia; ACE: Angiotensin-converting enzyme; SHR: Spontaneously hypertensive rats; SBP: Systolic blood pressure; DBP: Diastolic blood pressure; AUC: Area under curve; RAAS: Renin Angiotensin Aldosterone System.
    Matched MeSH terms: Heart Rate/drug effects
  11. Chin KW, Chin NM, Chin MK
    Med J Malaysia, 1994 Jun;49(2):142-8.
    PMID: 8090093
    Three millilitres of plain 0.5% bupivacaine were injected intrathecally at two different spinal interspaces (L2/3 and L4/5) and at two different speeds (15 and 30 sec) in four groups of ten patients. Injection at L2/3 over 15 sec produced a significantly higher mean maximum spread of analgesia (T6.4) when compared to injection at L4-5 over 15 sec (T10.3) (P < 0.05). Over the same interspace L2/3, injection over 15 sec also produced a higher level of spread as compared to the 30 sec group (p < 0.05). At 15 min there was a greater fall in blood pressure in the L2/3 15 sec group when compared to the other groups (p < 0.01). There was a further decrease in the blood pressure in L2/3 15 sec and L4/5 30 sec groups after 30 minutes of blockade (p < 0.01). Therefore close monitoring of cardiovascular parameters must be continued for at least 30 min in spinal anaesthesia with bupivacaine.
    Matched MeSH terms: Heart Rate/drug effects
  12. Poznanski RR, Cacha LA, Al-Wesabi YMS, Ali J, Bahadoran M, Yupapin PP, et al.
    Sci Rep, 2017 May 31;7(1):2746.
    PMID: 28566682 DOI: 10.1038/s41598-017-01849-3
    A model of solitonic conduction in neuronal branchlets with microstructure is presented. The application of cable theory to neurons with microstructure results in a nonlinear cable equation that is solved using a direct method to obtain analytical approximations of traveling wave solutions. It is shown that a linear superposition of two oppositely directed traveling waves demonstrate solitonic interaction: colliding waves can penetrate through each other, and continue fully intact as the exact pulses that entered the collision. These findings indicate that microstructure when polarized can sustain solitary waves that propagate at a constant velocity without attenuation or distortion in the absence of synaptic transmission. Solitonic conduction in a neuronal branchlet arising from polarizability of its microstructure is a novel signaling mode of electrotonic signals in thin processes (<0.5 μm diameter).
    Matched MeSH terms: Heart Rate/physiology
  13. 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: Heart Rate/physiology*
  14. Itagi AB, Arora D, Patil NA, Bailwad SA, Yunus GY, Goel A
    Int J Appl Basic Med Res, 2016 Jan-Mar;6(1):45-9.
    PMID: 26958522 DOI: 10.4103/2229-516X.174008
    An increase in the consumption of smokeless tobacco has been noticed among high school, college students, and adults. Despite the antiquity and popularity of chewing tobacco in India, its effects have not been investigated systematically in humans. The aim of this study was to investigate acute effects of gutkha chewing on heart rate variability (HRV) among healthy young adults.
    Matched MeSH terms: Heart Rate
  15. Nadia, M.N., Samsul Johari, M.A., Muhammad, M., Raha, A.R., Nurlia, Y.
    MyJurnal
    This study aimed to compare dexmedetomidine and propofol, in terms of haemodynamic parameters, respiratory rates and offset times, when used for sedation in patients undergoing elective orthopaedic and surgical procedures under regional anaesthesia. This was a prospective, randomised, single-blind study where 88 patients were recruited. Patients were randomised into two groups to receive either dexmedetomidine or propofol infusion. Central neuraxial blockade (spinal, epidural or combined spinal epidural) was performed. After ensuring an adequate block and stable haemodynamic parameters, dexmedetomidine was infused 15 minutes later at 0.4 μg/kg/hr, and propofol, at a target concentration of 2.5 μg/ml. Both drugs were titrated to achieve a bispectral index score of 70 before surgery commenced. Sedation level was monitored using the bispectral index score and assessed by the Observer Assessment of Alertness Scale score. Drug infusion was adjusted to maintain bispectral index scores ranging between 70-80 during surgery. Both groups showed reductions in mean arterial pressure and heart rate from baseline readings throughout the infusion time. However there was no significant reduction in the first 15 minutes from baseline (p > 0.05). Haemodynamic parameters and respiratory rate between both groups were not significantly different (p > 0.05). No patient demonstrated significant respiratory depression or SpO2 ≤ 95%. Offset times were also not significantly different between both groups (p = 0.594). There were no significant differences in haemodynamic parameters, respiratory rates and offset times between dexmedetomidine and propofol used for sedation in patients undergoing elective orthopaedic and surgical procedures under regional anaesthesia.
    Matched MeSH terms: Heart Rate
  16. Faridah Hanim Zam Zam, Nazimah Idris, Tham, Seng Woh
    MyJurnal
    Background: Fetal surveillance in labour is performed mostly to identify fetuses at risk of hypoxia in order to reduce neonatal morbidity and mortality by initiating timely intervention. While normal and abnormal fetal heart rate (FHR) patterns have been well recognised and characterized for the first stage of labour, FHR patterns during the second stage of labour commonly showed some forms of abnormalities leading to problems in interpretation, particularly in predicting fetal hypoxia and acidosis. This study aims to identify patterns of FHR tracing during the second stage of labour associated with neonatal acidosis. Methods: A prospective cross sectional study was conducted in the Labour Ward of a state referral hospital. The study population were patients with low-risk
    singleton pregnancies between 37 to 42 weeks gestation who had normal cardiotocograph (CTG) tracing in the first stage of labour. CTG was recorded during the second stage of labour and neonatal umbilical cord blood was obtained for acid-base analysis immediately after birth prior to the delivery of placenta. FHR patterns were grouped according to modified Melchior and Barnard’s
    classification and matched with neonatal acid-base status. Patients with normal FHR pattern in the second stage acted as control. Results: A total of 111 matched pairs were analysed. Ninety nine (89.2%) second stage FHR tracings showed abnormal features when compared to control. There were significantly more neonatal acidosis and hypercapnia in type 1b, type 2a, type 2b and type 3 CTG patterns compared to control, in increasing order of severity. In addition, types 2b and 3 showed significant difference in the base excess. Conclusion: Certain second stage fetal heart rate
    patterns were found to be associated with neonatal acidosis.
    Matched MeSH terms: Heart Rate, Fetal
  17. Ken DK, Ng KH
    Med J Malaysia, 1974 Mar;28(3):191-3.
    PMID: 4278259
    Matched MeSH terms: Heart Rate/drug effects
  18. 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: Heart Rate/drug effects; Heart Rate/physiology
  19. Goh CH, Tan LK, Lovell NH, Ng SC, Tan MP, Lim E
    Comput Methods Programs Biomed, 2020 Nov;196:105596.
    PMID: 32580054 DOI: 10.1016/j.cmpb.2020.105596
    BACKGROUND AND OBJECTIVES: Continuous monitoring of physiological parameters such as photoplethysmography (PPG) has attracted increased interest due to advances in wearable sensors. However, PPG recordings are susceptible to various artifacts, and thus reducing the reliability of PPG-driven parameters, such as oxygen saturation, heart rate, blood pressure and respiration. This paper proposes a one-dimensional convolution neural network (1-D-CNN) to classify five-second PPG segments into clean or artifact-affected segments, avoiding data-dependent pulse segmentation techniques and heavy manual feature engineering.

    METHODS: Continuous raw PPG waveforms were blindly allocated into segments with an equal length (5s) without leveraging any pulse location information and were normalized with Z-score normalization methods. A 1-D-CNN was designed to automatically learn the intrinsic features of the PPG waveform, and perform the required classification. Several training hyperparameters (initial learning rate and gradient threshold) were varied to investigate the effect of these parameters on the performance of the network. Subsequently, this proposed network was trained and validated with 30 subjects, and then tested with eight subjects, with our local dataset. Moreover, two independent datasets downloaded from the PhysioNet MIMIC II database were used to evaluate the robustness of the proposed network.

    RESULTS: A 13 layer 1-D-CNN model was designed. Within our local study dataset evaluation, the proposed network achieved a testing accuracy of 94.9%. The classification accuracy of two independent datasets also achieved satisfactory accuracy of 93.8% and 86.7% respectively. Our model achieved a comparable performance with most reported works, with the potential to show good generalization as the proposed network was evaluated with multiple cohorts (overall accuracy of 94.5%).

    CONCLUSION: This paper demonstrated the feasibility and effectiveness of applying blind signal processing and deep learning techniques to PPG motion artifact detection, whereby manual feature thresholding was avoided and yet a high generalization ability was achieved.

    Matched MeSH terms: Heart Rate
  20. Razak MR, Aris AZ, Yusoff FM, Yusof ZNB, Abidin AAZ, Kim SD, et al.
    Environ Geochem Health, 2023 Jun;45(6):3567-3583.
    PMID: 36450975 DOI: 10.1007/s10653-022-01442-2
    Bisphenol A (BPA) is a well-known endocrine-disrupting compound that causes several toxic effects on human and aquatic organisms. The restriction of BPA in several applications has increased the substituted toxic chemicals such as bisphenol F (BPF) and bisphenol S (BPS). A native tropical freshwater cladoceran, Moina micrura, was used as a bioindicator to assess the adverse effects of bisphenol analogues at molecular, organ, individual and population levels. Bisphenol analogues significantly upregulated the expressions of stress-related genes, which are the haemoglobin and glutathione S-transferase genes, but the sex determination genes such as doublesex and juvenile hormone analogue genes were not significantly different. The results show that bisphenol analogues affect the heart rate and mortality rate of M. micrura. The 48-h lethal concentration (LC50) values based on acute toxicity for BPA, BPF and BPS were 611.6 µg L-1, 632.0 µg L-1 and 819.1 µg L-1, respectively. The order of toxicity based on the LC50 and predictive non-effect concentration values were as follows: BPA > BPF > BPS. Furthermore, the incorporated method combining the responses throughout the organisation levels can comprehensively interpret the toxic effects of bisphenol analogues, thus providing further understanding of the toxicity mechanisms. Moreover, the output of this study produces a comprehensive ecotoxicity assessment, which provides insights for the legislators regarding exposure management and mitigation of bisphenol analogues in riverine ecosystems.
    Matched MeSH terms: Heart Rate
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