Displaying publications 41 - 60 of 92 in total

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  1. Tan PJ, Appleton DR, Mustafa MR, Lee HB
    Phytochem Anal, 2012 Jan-Feb;23(1):52-9.
    PMID: 21692117 DOI: 10.1002/pca.1324
    Photodynamic therapy is a treatment modality that involves site-directed generation of cytotoxic reactive oxygen species by light-activated photosensitisers.
  2. Lang CC, Jamal SK, Mohamed Z, Mustafa MR, Mustafa AM, Lee TC
    Br J Clin Pharmacol, 2003 Jun;55(6):588-90.
    PMID: 12814453
    AIMS: Nafcillin (Wyeth Laboratories, Philadelphia, PA, USA) has been reported to induce the metabolism of cyclosporin and warfarin, which are known substrates of cytochrome P-450 (CYP). However, there has not been any report to date on its possible interaction with nifedipine, an index substrate of the enzyme, CYP3A4.

    METHODS: Nine healthy normotensive subjects participated in this randomized placebo-controlled two-way crossover study examining the effects of 5 days' pretreatment of nafcillin 500 mg or placebo four times daily on the pharmacokinetics of an oral dose of nifedipine 10 mg. Plasma nifedipine concentrations were measured by gas chromatography-mass spectro.

    RESULTS: The area under the plasma nifedipine concentration-time curve (AUC0-alpha) in nafcillin-pretreated subjects (80.9 +/- 32.9 micro g l-1 h-1) was significantly decreased compared with subjects who received only nifedipine (216.4 +/- 93.2 micro g l-1 h-1) (P < 0.001). Total plasma clearance of nifedipine (CL/F) was significantly increased with nafcillin pretreatment (138.5 +/- 42.0 l h-1 vs 56.5 +/- 32.0 l h-1) (P < 0.002).

    CONCLUSIONS: The results show that nafcillin pretreatment markedly increased the clearance of nifedipine and suggest that nafcillin is a potent inducer of CYP enzyme.

  3. Chimonyo VGP, Govender L, Nyathi M, Scheelbeek PFD, Choruma DJ, Mustafa M, et al.
    Front Nutr, 2023;10:1060246.
    PMID: 36793925 DOI: 10.3389/fnut.2023.1060246
    INTRODUCTION: Intercropping cereals with legumes can intensify rainfed cereal monocropping for improved household food and nutritional security. However, there is scant literature confirming the associated nutritional benefits.

    METHODOLOGY: A systematic review and meta-analysis of nutritional water productivity (NWP) and nutrient contribution (NC) of selected cereal-legume intercrop systems was conducted through literature searches in Scopus, Web of Science and ScienceDirect databases. After the assessment, only nine articles written in English that were field experiments comprising grain cereal and legume intercrop systems were retained. Using the R statistical software (version 3.6.0), paired t-tests were used to determine if differences existed between the intercrop system and the corresponding cereal monocrop for yield (Y), water productivity (WP), NC, and NWP.

    RESULTS: The intercropped cereal or legume yield was 10 to 35% lower than that for the corresponding monocrop system. In most instances, intercropping cereals with legumes improved NY, NWP, and NC due to their added nutrients. Substantial improvements were observed for calcium (Ca), where NY, NWP, and NC improved by 658, 82, and 256%, respectively.

    DISCUSSION: Results showed that cereal-legume intercrop systems could improve nutrient yield in water-limited environments. Promoting cereal- legume intercrops that feature nutrient-dense legume component crops could contribute toward addressing the SDGs of Zero Hunger (SDG 3), Good Health and Well-3 (SDG 2) and Responsible consumption and production (SDG 12).

  4. Mudhafar M, Zainol I, Alsailawi HA, Zorah M, Karhib MM, Mahmood Mahdi N
    Heliyon, 2023 May;9(5):e15838.
    PMID: 37206015 DOI: 10.1016/j.heliyon.2023.e15838
    The present study was conducted to prepare the fish scales' hydroxyapatite/collagen beads (FsHA/FsCol) and characterize their biological, physical, and chemical properties. A new method was used to prepare FsHA/FsCol composite beads by infiltrating the beads of FsHA in the solution of FsCol as a green method. X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) analysis, Fourier-transform infrared (FTIR) spectroscopy analysis and energy dispersive X-ray analysis (EDX), used to evaluate the physical-chemical properties of the synthesized samples. Meanwhile, the cytotoxic and attachment studies of the FsHA/FsCol beads were used to investigate the biological features against the MG-63 human cell line. The results specified the efficiency of the new method, functional groups of FsCol were indicated to be present inside the beads of FsHA according to the XRD analysis which shows the functional peaks of FsCol. The SEM image were conformed successfully use starch as a porous agent to increasing the porous of the FsHA beads after adding 20 wt% of it. Alamar Blue assay has been used to evaluate the cytotoxicity of FsHA/FsCol beads the results were shown 87% average cell viability of the MG-63 human cell line on the beads and attached very well to the surface of the composites, indicating no toxicity being exerted by all the composites at high concentrations.
  5. Mustafa M, Hatah E, Makmor-Bakry M
    Res Social Adm Pharm, 2023 Apr;19(4):673-680.
    PMID: 36529621 DOI: 10.1016/j.sapharm.2022.12.005
    BACKGROUND: Pharmacists' roles have been evolving to include more patient-centered care services such as medication reviews that help patients receive the most benefits from their medication. In Malaysia, medication review is yet to be widely implemented in the community pharmacy setting for several reasons, including the non-dispensing separation healthcare system. To establish and implement a feasible medication review service model in Malaysia, it is important to gather community pharmacists' perspectives on such services.

    AIM: To explore community pharmacists' perceptions of barriers, facilitators, and strategies for the implementation of a medication review service in Malaysia.

    METHODS: A focus group discussion followed by semi-structured interviews were conducted among purposively sampled community pharmacists with an interest in medication review service. A framework analysis approach using the consolidated framework for implementation research (CFIR) was utilized to generate and analyze the data. After data mapping, the CFIR-ERIC (expert recommendations for implementing change) matching tool was used to generate the strategies according to the barriers identified.

    RESULTS: Twenty community pharmacists participated in this study. Several barriers and facilitators to service implementation were identified based on the respondent's input. The CFIR-ERIC strategies matching tool analysis reported potential plans that can mitigate the barriers such as: identify and prepare champions, conduct local consensus discussions, conduct educational meetings, alter incentive/allowance structures, and develop a formal implementation blueprint.

    CONCLUSION: Multifaceted strategies are required to ensure the successful implementation of medication review services in Malaysia. The findings of this study will assist in the development of a sustainable medication review service blueprint for the Malaysian community pharmacy setting.

  6. Lee SH, Yeoh ZX, Sachlin IS, Gazali N, Soelar SA, Foo CY, et al.
    Sci Rep, 2022 02 08;12(1):2111.
    PMID: 35136124 DOI: 10.1038/s41598-022-06029-6
    Alterations in the three chemosensory modalities-smell, taste, and chemesthesis-have been implicated in Coronavirus Disease 2019 (COVID-19), yet emerging data suggest a wide geographic and ethnic variation in the prevalence of these symptoms. Studies on chemosensory disorders in COVID-19 have predominantly focused on Caucasian populations whereas Asians remain understudied. We conducted a nationwide, multicentre cross-sectional study using an online questionnaire on a cohort of RT-PCR-confirmed adult COVID-19 patients in Malaysia between 6 June and 30 November 2020. The aim of our study was to investigate their presenting symptoms and assess their chemosensory function using self-ratings of perceived smell, taste, chemesthesis, and nasal blockage. In this cohort of 498 patients, 41.4% reported smell and/or taste loss when diagnosed with COVID-19, which was the commonest symptom. Blocked nose, loss of appetite, and gastrointestinal disturbances were independent predictors of smell and/or taste loss on multivariate analysis. Self-ratings of chemosensory function revealed a reduction in smell, taste, and chemesthesis across the entire cohort of patients that was more profound among those reporting smell and/or taste loss as their presenting symptom. Perceived nasal obstruction accounted for only a small proportion of changes in smell and taste, but not for chemesthesis, supporting viral disruption of sensorineural mechanisms as the dominant aetiology of chemosensory dysfunction. Our study suggests that chemosensory dysfunction in COVID-19 is more widespread than previously reported among Asians and may be related to the infectivity of viral strains.Study Registration: NMRR-20-934-54803 and NCT04390165.
  7. Tijjani Salihu A, Muthuraju S, Aziz Mohamed Yusoff A, Ahmad F, Zulkifli Mustafa M, Jaafar H, et al.
    Behav Brain Res, 2016 10 01;312:374-84.
    PMID: 27327104 DOI: 10.1016/j.bbr.2016.06.034
    The present study aimed to investigate the behavior and neuronal morphological changes in the perihaemorrhagic tissue of the mouse intracerebellar haemorrhage experimental model. Adult male Swiss albino mice were stereotactically infused with collagenase type VII (0.4U/μl of saline) unilaterally in to the cerebellum, following anaesthesia. Motor deficits were assessed using open field and composite score for evaluating the mouse model of cerebellar ataxia at 1, 3, 7, 14 and 21 days after collagenase infusion. The animals were sacrificed at the same time interval for evaluation of perihaematomal neuronal degeneration using haematoxylin and eosin staining and Annexin V-FITC/Propidium iodide assay. At the end of the study, it was found that infusion of 0.4U collagenase produces significant locomotor and ataxic deficit in the mice especially within the first week post surgery, and that this gradually improved within three weeks. Neuronal degeneration evident by cytoplasmic shrinkage and nuclear pyknosis was observed at the perihaematomal area after one day; especially at 3 and 7 days post haemorrhage. By 21 days, both the haematoma and degenerating neurons in the perihaematomal area were phagocytosed and the remaining neuronal cells around the scar tissue appeared normal. Moreover, Annexin-V/propidium iodide-positive cells were observed at the perihaematomal area at 3 and 7 days implying that the neurons likely die via apoptosis. It was concluded that a population of potentially salvageable neurons exist in the perihaematomal area after cerebellar haemorrhage throughout a wide time window that could be amenable to treatment.
  8. Tan XL, Azam-Ali S, Goh EV, Mustafa M, Chai HH, Ho WK, et al.
    Front Nutr, 2020;7:601496.
    PMID: 33363196 DOI: 10.3389/fnut.2020.601496
    Rapid population growth, climate change, intensive monoculture farming, and resource depletion are among the challenges that threaten the increasingly vulnerable global agri-food system. Heavy reliance on a few major crops is also linked to a monotonous diet, poor dietary habits, and micronutrient deficiencies, which are often associated with diet-related diseases. Diversification-of both agricultural production systems and diet-is a practical and sustainable approach to address these challenges and to improve global food and nutritional security. This strategy is aligned with the recommendations from the EAT-Lancet report, which highlighted the urgent need for increased consumption of plant-based foods to sustain population and planetary health. Bambara groundnut (Vigna subterranea (L.) Verdc.), an underutilized African legume, has the potential to contribute to improved food and nutrition security, while providing solutions for environmental sustainability and equity in food availability and affordability. This paper discusses the potential role of Bambara groundnut in diversifying agri-food systems and contributing to enhanced dietary and planetary sustainability, with emphasis on areas that span the value chain: from genetics, agroecology, nutrition, processing, and utilization, through to its socioeconomic potential. Bambara groundnut is a sustainable, low-cost source of complex carbohydrates, plant-based protein, unsaturated fatty acids, and essential minerals (magnesium, iron, zinc, and potassium), especially for those living in arid and semi-arid regions. As a legume, Bambara groundnut fixes atmospheric nitrogen to improve soil fertility. It is resilient to adverse environmental conditions and can yield on poor soil. Despite its impressive nutritional and agroecological profile, the potential of Bambara groundnut in improving the global food system is undermined by several factors, including resource limitation, knowledge gap, social stigma, and lack of policy incentives. Multiple research efforts to address these hurdles have led to a more promising outlook for Bambara groundnut; however, there is an urgent need to continue research to realize its full potential.
  9. Maeno H, Wong PF, AbuBakar S, Yang M, Sam SS, Jamil-Abd J, et al.
    Micromachines (Basel), 2021 Nov 30;12(12).
    PMID: 34945351 DOI: 10.3390/mi12121503
    Serum is commonly used as a specimen in immunoassays but the presence of heterophilic antibodies can potentially interfere with the test results. Previously, we have developed a microfluidic device called: 3D Stack for enzyme-linked immunosorbent assay (ELISA). However, its evaluation was limited to detection from a single protein solution. Here, we investigated the sensitivity of the 3D Stack in detecting a severe dengue biomarker-soluble CD163 (sCD163)-within the serum matrix. To determine potential interactions with serum matrix, a spike-and-recovery assay was performed, using 3D Stacks with and without surface modification by an EDC-NHS (N-ethyl-N'-(3-(dimethylamino)propyl)carbodiimide/N-hydroxysuccinimide) coupling. Without surface modification, a reduced analyte recovery in proportion to serum concentration was observed because of the Vroman effect, which resulted in competitive displacement of coated capture antibodies by serum proteins with stronger binding affinities. However, EDC-NHS coupling prevented antibody desorption and improved the sensitivity. Subsequent comparison of sCD163 detection using a 3D Stack with EDC-NHS coupling and conventional ELISA in dengue patients' sera revealed a high correlation (R = 0.9298, p < 0.0001) between the two detection platforms. Bland-Altman analysis further revealed insignificant systematic error between the mean differences of the two methods. These data suggest the potentials of the 3D Stack for further development as a detection platform.
  10. Omer ME, Abu Bakar M, Adam M, Mustafa M
    Asian Pac J Cancer Prev, 2021 Apr 01;22(4):1045-1053.
    PMID: 33906295 DOI: 10.31557/APJCP.2021.22.4.1045
    OBJECTIVE: Cure rate models are survival models, commonly applied to model survival data with a cured fraction. In the existence of a cure rate, if the distribution of survival times for susceptible patients is specified, researchers usually prefer cure models to parametric models. Different distributions can be assumed for the survival times, for instance, generalized modified Weibull (GMW), exponentiated Weibull (EW), and log-beta Weibull. The purpose of this study is to select the best distribution for uncured patients' survival times by comparing the mixture cure models based on the GMW distribution and its particular cases.

    MATERIALS AND METHODS: A data set of 91 patients with high-risk acute lymphoblastic leukemia (ALL) followed for five years from 1982 to 1987 was chosen for fitting the mixture cure model. We used the maximum likelihood estimation technique via R software 3.6.2 to obtain the estimates for parameters of the proposed model in the existence of cure rate, censored data, and covariates. For the best model choice, the Akaike information criterion (AIC) was implemented.

    RESULTS: After comparing different parametric models fitted to the data, including or excluding cure fraction, without covariates, the smallest AIC values were obtained by the EW and the GMW distributions, (953.31/969.35) and (955.84/975.99), respectively. Besides, assuming a mixture cure model based on GMW with covariates, an estimated ratio between cure fractions for allogeneic and autologous bone marrow transplant groups (and its 95% confidence intervals) were 1.42972 (95% CI: 1.18614 - 1.72955).

    CONCLUSION: The results of this study reveal that the EW and the GMW distributions are the best choices for the survival times of Leukemia patients.
    .

  11. Chuah CH, Chow TS, Hor CP, Cheng JT, Ker HB, Lee HG, et al.
    Clin Infect Dis, 2021 Nov 19.
    PMID: 34849615 DOI: 10.1093/cid/ciab962
    BACKGROUND: Role of favipiravir in preventing disease progression in COVID-19 remains uncertain. We aimed to determine its effect in preventing disease progression from non-hypoxia to hypoxia among high risk COVID-19 patients.

    STUDY DESIGN: This was an open-label, randomized clinical trial conducted at 14 public hospitals across Malaysia from February to June 2021 among 500 symptomatic, RT-PCR confirmed COVID-19 patients, aged ≥50 years with ≥1 co-morbidity, and hospitalized within first 7 days of illness. Patients were randomized on 1:1 ratio to favipiravir plus standard care or standard care alone. Favipiravir was administered at 1800mg twice-daily on day 1 followed by 800mg twice-daily until day 5. The primary endpoint was rate of clinical progression from non-hypoxia to hypoxia. Secondary outcomes included rates of mechanical ventilation, intensive care unit (ICU) admission, and in-hospital mortality.

    RESULTS: Among 500 patients were randomized (mean age, 62.5 [SD 8.0] years; 258 women [51.6%]; and 251 [50.2%] had COVID-19 pneumonia), 487 (97.4%) patients completed the trial. Clinical progression to hypoxia occurred in 46 (18.4%) patients on favipiravir plus standard care and 37 (14.8%) on standard care alone (OR 1.30; 95%CI, 0.81-2.09; P=.28). All three pre-specified secondary end points were similar between both groups. Mechanical ventilation occurred in 6 (2.4%) vs 5 (2.0%) (OR 1.20; 95%CI, 0.36-4.23; P=.76), ICU admission in 13 (5.2%) vs 12 (4.8%) (OR 1.09; 95%CI, 0.48-2.47; P=.84), and in-hospital mortality in 5 (2.0%) vs 0 (OR 12.54; 95%CI, 0.76- 207.84; P=.08).

    CONCLUSIONS: Among COVID-19 patients at high risk of disease progression, early treatment with oral favipiravir did not prevent their disease progression from non-hypoxia to hypoxia.

  12. Umar ZD, Aziz NA, Zulkifli SZ, Mustafa M
    MethodsX, 2017;4:104-117.
    PMID: 28280689 DOI: 10.1016/j.mex.2017.02.003
    Polycyclic Aromatic Hydrocarbons (PAHs) are complex and widely distributed environmental pollutants that can affect living ecosystems. This study was conducted to rapidly degrade phenanthrene and pyrene representing low and high molecular weight of PAHs, respectively. Cronobacter sakazakii MM045 (KT933253) was identified from used engine oil of contaminated soil. PAHs biodegradation was carried out using 2,6-dichlorophenol indophenol (DCPIP) assay. Biodegradation influencing factors including agitation, temperature, pH, inoculums volume and salinity were enhanced using Response Surface Methodology (RSM) by Central Composite Design (CCD). Phenanthrene and pyrene biodegrading metabolites were identified using gas chromatography mass spectrophotometer (GCMS). •Initial biodegradation indicated 75.2% and 54.3% phenanthrene and pyrene degraded by C. sakazakii MM045 within 24 h. After CCD optimisation, 100% degradation was achieved for each of the phenanthrene and pyrene, resulting in the formation of intermediate metabolites.•The identified phenanthrene metabolites were 3,4-dihydroxyphenathrene, phthalic acid, pyruvic acid, acetic acid and oxalic acid. Pyrene intermediates comprised pyrene cis-4,5-dihydrodiol, 3,4-dihydroxyphenanthrene, phthalic acid, pyruvic acid, acetic acid and lactic acid.•Cronbacter sakazakii MM045 was proven to be rapid and effective in degrading PAHs within 24 h despite the unavailability of existing literatures on PAHs biodegradation.
  13. Yaacob I, Mustafa M
    Singapore Med J, 1994 Oct;35(5):512-4.
    PMID: 7701374
    Fifty-eight patients were ventilated for acute respiratory failure complicating respiratory diseases between 1985 to 1990. There were 19 cases of chronic obstructive airway disease (COAD), 17 cases of asthma, 16 cases of pneumonia and 6 cases with other diagnoses. Overall, 40% of patients survived and were discharged from the ward. Patients with pneumonia had the lowest survival rate (25%) whilst the survival rates for asthma and COAD were 47% and 42% respectively. Increasing age had an inverse relationship to survival rate (r = 0.96, p < 0.05) but the duration of ventilation did not correlate with survival. Patients who were electively ventilated before respiratory arrest had a better chance of survival (57%) compared with only 18% survival rate in patients who were ventilated as an emergency (x2 = 4.47, p < 0.05). Patients who developed other organ failure had higher mortality (71%) than those who did not (22%; x2 = 2.14, p < 0.05). We conclude that patients younger than 50 years of age, who were electively ventilated and without other organ failure had a better immediate survival after assisted ventilation.
  14. Lavanya Priya KP, Gill S, Banik A, Marvaniya J, Marella K, Anusha Y, et al.
    J Pharm Bioallied Sci, 2023 Jul;15(Suppl 1):S132-S136.
    PMID: 37654297 DOI: 10.4103/jpbs.jpbs_436_22
    INTRODUCTION: The best treatment for the deeply carious tooth that cannot be restored is by the root canal therapy. This method has saved many patients from the loss of tooth. The common practice is either to deliver a full crown or close the access cavity with restoration. Hence in this study, the clinical longevity of the routine practice is tested for by analyzing the fracture toughness and the survival of the teeth that were restored endodontically with various materials.

    MATERIALS AND METHODS: The hospital records were retrospectively evaluated from 2000 to 2010 for a decade. The demographics as well as the survival and the failure rates noted and compared for the various types of the restorations. The number of the walls of the teeth was also compared.

    RESULTS: Thousand teeth were considered in the study. Less than 7% of teeth had coronal fractures. Of the 93% teeth that had survived, the most common restoration was Individual post (+ crown) followed by GIC, amalgams, and crowns. The mean survival of the crown+ bridge & gold restoration was highest. The mean survival was 10 ± 2 years for the restored teeth without any fractures at the coronal level. The failure was greatest for the GIC followed by amalgam, and the variations when compared with other restorations were significant. There was no significant difference for the number of the walls on the crown; however, the number of walls present was proportional to the survival rate.

    CONCLUSION: The teeth that were covered with a crown were comparatively fracture resistant and had a better survival rate compared to other restorations. GIC showed highest fracture, and the post core with crown had the best survival. Restoration of the lost crown architecture and the reinforcement are the best methods that can be followed for the survivals.

  15. Ali A, Wee Pheng T, Mustafa MA
    J Appl Microbiol, 2015 Jun;118(6):1456-64.
    PMID: 25727701 DOI: 10.1111/jam.12782
    To evaluate the potential use of lemongrass essential oil vapour as an alternative for synthetic fungicides in controlling anthracnose of papaya.
  16. Lau YS, Kwan CY, Ku TC, Hsieh WT, Wang HD, Nishibe S, et al.
    J Ethnopharmacol, 2012 Sep 28;143(2):565-71.
    PMID: 22835814 DOI: 10.1016/j.jep.2012.07.012
    The leaves extract of Apocynum venetum (AVLE), also known as "luobuma", have long been used in traditional Chinese medicine to treat hypertension and depression in parts of China and it has been shown to possess anti-oxidant and anti-lipid peroxidation effects. AVLE (10 μg/ml) has been reported to have a long-lasting endothelium-dependent relaxant effect and this effect has been proposed to be due to its nitric oxide(NO)-releasing and superoxide anion(SOA)-scavenging properties.
  17. Isa NM, Abdelwahab SI, Mohan S, Abdul AB, Sukari MA, Taha MM, et al.
    Braz. J. Med. Biol. Res., 2012 Jun;45(6):524-30.
    PMID: 22358425
    The current in vitro study was designed to investigate the anti-inflammatory, cytotoxic and antioxidant activities of boesenbergin A (BA), a chalcone derivative of known structure isolated from Boesenbergia rotunda. Human hepatocellular carcinoma (HepG2), colon adenocarcinoma (HT-29), non-small cell lung cancer (A549), prostate adenocarcinoma (PC3), and normal hepatic cells (WRL-68) were used to evaluate the cytotoxicity of BA using the MTT assay. The antioxidant activity of BA was assessed by the ORAC assay and compared to quercetin as a standard reference antioxidant. ORAC results are reported as the equivalent concentration of Trolox that produces the same level of antioxidant activity as the sample tested at 20 µg/mL. The toxic effect of BA on different cell types, reported as IC50, yielded 20.22 ± 3.15, 10.69 ± 2.64, 20.31 ± 1.34, 94.10 ± 1.19, and 9.324 ± 0.24 µg/mL for A549, PC3, HepG2, HT-29, and WRL-68, respectively. BA displayed considerable antioxidant activity, when the results of ORAC assay were reported as Trolox equivalents. BA (20 µg/mL) and quercetin (5 µg/mL) were equivalent to a Trolox concentration of 11.91 ± 0.23 and 160.32 ± 2.75 µM, respectively. Moreover, the anti-inflammatory activity of BA was significant at 12.5 to 50 µM and without any significant cytotoxicity for the murine macrophage cell line RAW 264.7 at 50 µM. The significant biological activities observed in this study indicated that BA may be one of the agents responsible for the reported biological activities of B. rotunda crude extract.
  18. Aloysius UI, Achike FI, Mustafa MR
    Vascul. Pharmacol., 2012 Sep-Oct;57(2-4):81-90.
    PMID: 22172524 DOI: 10.1016/j.vph.2011.11.009
    The female gender reduces the risk, but succumbs more to cardiovascular disease. The hypothesis that short-term (8weeks) Streptozotocin-induced diabetes could produce greater female than male vascular tissue reactivity and the mechanistic basis were explored. Aortic ring responses to Phenylephrine were examined in age- and sex-matched normoglycaemic/diabetic rats. The normoglycaemic male tissue contracted significantly more than the normoglycaemic female and the male/female diabetic tissues. Endothelial-denudation, l-NAME or MB reversed these differences suggesting an EDNO-cGMP dependence. 17β-oestradiol exerted relaxant effect on all endothelium-denuded (and normoglycaemic endothelium-intact male) tissues, but not endothelium-intact normoglycaemic female. The greater male tissue contraction is attributable to absent 17β-oestradiol-modulated relaxation. Indomethacin blockade of COX attenuated male normoglycaemic and female diabetic tissue contraction (both reversed by l-NAME), but augmented diabetic male tissue contraction. These data are consistent with the raised contractile TXA(2) and PGE(2) in normoglycaemic male and diabetic female tissues, and the relaxant PGI(2) in diabetic male (and female). The higher levels of PGI(2) in the normoglycaemic and diabetic female perhaps explain their greater relaxant response to Acetylcholine compared to the respective male. In conclusion, there is an endothelium-dependent gender difference in the effect of short term diabetes on vascular tissue reactivity which is COX mediated.
  19. Ajay M, Chai HJ, Mustafa AM, Gilani AH, Mustafa MR
    J Ethnopharmacol, 2007 Feb 12;109(3):388-93.
    PMID: 16973321
    Previous studies have demonstrated the anti-hypertensive effects of Hibiscus sabdariffa L. (HS) in both humans and experimental animals. To explore the mechanisms of the anti-hypertensive effect of the HS, we examined the effects of a crude methanolic extract of the calyces of HS (HSE) on vascular reactivity in isolated aortas from spontaneously hypertensive rats. HSE relaxed, concentration-dependently, KCl (high K(+), 80 mM)- and phenylephrine (PE, 1 microM)-pre-contracted aortic rings, with a greater potency against the alpha(1)-adrenergic receptor agonist. The relaxant effect of HSE was partly dependent on the presence of a functional endothelium as the action was significantly reduced in endothelium-denuded aortic rings. Pretreatment with atropine (1 microM), L-NAME (10 microM) or methylene blue (10 microM), but not indomethacin (10 microM), significantly blocked the relaxant effects of HSE. Endothelium-dependent and -independent relaxations induced by acetylcholine and sodium nitroprusside, respectively, were significantly enhanced in aortic rings pretreated with HSE when compared to those observed in control aortic rings. The present results demonstrated that HSE has a vasodilator effect in the isolated aortic rings of hypertensive rats. These effects are probably mediated through the endothelium-derived nitric oxide-cGMP-relaxant pathway and inhibition of calcium (Ca(2+))-influx into vascular smooth muscle cells. The present data further supports previous in vivo findings and the traditional use of HS as an anti-hypertensive agent.
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