Displaying publications 421 - 440 of 1776 in total

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  1. Muhd Yusoff NH, Zainol Rashid Z, Sulong A, Shafiee MN, Ismail Z
    Malays J Pathol, 2019 Dec;41(3):351-354.
    PMID: 31901921
    INTRODUCTION: Neisseria meningitidis infections often cause severe meningitis as well as bacteraemia. However, cellulitis in meningococcal diseases have rarely been described. Here, we report a case of right lower limb cellulitis caused by N. meningitidis.

    CASE REPORT: A 69-year-old woman presented with fever and lower limb swelling. She had diabetes mellitus, hypertension, dyslipidaemia and a history of surgical resection of vulvar carcinoma. N. meningitidis was isolated from her blood culture.

    DISCUSSION: This report provides additional evidence in support of N. meningitidis as a cause of cellulitis.

  2. Shirajum Monir M, Yusoff SM, Mohamad A, Ina-Salwany MY
    J Aquat Anim Health, 2020 06;32(2):65-76.
    PMID: 32331001 DOI: 10.1002/aah.10099
    The production of tilapia Oreochromis spp. is rapidly growing throughout the world, but atypical motile aeromonad septicemia (MAS) is a current threat to the tilapia farming industry. The etiological agent of this disease is usually Aeromonas hydrophila. Mortality rates due to MAS are frequently high, resulting in a devastating negative impact on this industry worldwide; therefore, proper control measures regarding both prevention and treatment are necessary. Although vaccines against MAS for tilapia are available, their effectiveness is entirely dependent on the specific strain of problematic bacteria. Until now, whole-cell inactivated A. hydrophila vaccines for tilapia have exhibited the highest level of protection over live attenuated and recombinant vaccines. Among the various vaccine administration systems, only intraperitoneal (i.p.) injections of the A. hydrophila vaccine into tilapia were found to provide prominent immune protection. Vaccine efficacy was primarily measured by using the i.p. injection challenge model and estimating the relative percent survival of the immunized tilapia. Freund's incomplete adjuvant showed to be the most effective for tilapia MAS vaccines. In this review, multiple factors that directly or indirectly influence the efficacy of MAS vaccines for tilapia (adjuvants, challenge models, immunization doses and duration, and size of vaccinated fish) are discussed.
  3. Zhang Y, Liu X, Yusoff M, Razali MH
    Scanning, 2021;2021:3839235.
    PMID: 34630820 DOI: 10.1155/2021/3839235
    Flower-like titanium dioxide (TiO2) nanostructures are successfully synthesized using a hybrid sol-gel and a simple hydrothermal method. The sample was characterized using various techniques to study their physicochemical properties and was tested as a photocatalyst for methyl orange degradation and as an antibacterial material. Raman spectrum and X-ray diffraction (XRD) pattern show that the phase structure of the synthesized TiO2 is anatase with 80-100 nm in diameter and 150-200 nm in length of flower-like nanostructures as proved by field emission scanning electron microscope (FESEM). The energy-dispersive X-ray spectroscopy (EDS) analysis of flower-like anatase TiO2 nanostructure found that only titanium and oxygen elements are present in the sample. The anatase phase was confirmed further by a high-resolution transmission electron microscope (HRTEM) and selected area electron diffraction (SAED) pattern analysis. The Brunauer-Emmett-Teller (BET) result shows that the sample had a large surface area (108.24 m2/g) and large band gap energy (3.26 eV) due to their nanosize. X-ray photoelectron spectroscopy (XPS) analysis revealed the formation of Ti4+ and Ti3+ species which could prevent the recombination of the photogenerated electron, thus increased the electron transportation and photocatalytic activity of flower-like anatase TiO2 nanostructure to degrade the methyl orange (83.03%) in a short time (60 minutes). These properties also support the good performance of flower-like titanium dioxide (TiO2) nanostructure as an antibacterial material which is comparable with penicillin which is 13.00 ± 0.02 mm inhibition zone against Staphylococcus aureus.
  4. Ahmed Z, Yusoff MS, Kamal NHM, Aziz HA
    Waste Manag Res, 2021 Nov;39(11):1396-1405.
    PMID: 33928820 DOI: 10.1177/0734242X211012775
    The removal of concentrated colour (around 5039 Pt-Co) and chemical oxygen demand (COD; around 4142 mg L-1) from matured landfill leachate through a novel combination of humic acid extraction and coagulation with natural oil palm trunk starch (OPTS) was investigated in this study. Central composite design from response surface methodology of Design Expert-10 software executed the experimental design to correlate experimental factors with desired responses. Analysis of variance developed the quadratic model for four factors (e.g. coagulant dosage, slow mixing speed and time and centrifugation duration) and two responses (% removal of colour, COD). The model confirmed the highest colour (84.96%) and COD (48.84%) removal with a desirability function of 0.836 at the optimum condition of 1.68 g L-1 coagulant dose, 19.11 rpm slow mixing speed, 16.43 minutes for mixing time and 35.75 minutes for centrifugation duration. Better results of correlation coefficient (R2 = 0.98 and 0.96) and predicted R2 (0.94 and 0.84) indicates the model significance. Electron microscopic images display the amalgamation of flocs through bridging. Fourier transforms infrared spectra confirmed the existence of selected organic groups in OPTS, which eventually signifies the applied method.
  5. Kuppusamy P, Yusoff MM, Maniam GP, Govindan N
    Saudi Pharm J, 2016 Jul;24(4):473-84.
    PMID: 27330378 DOI: 10.1016/j.jsps.2014.11.013
    The field of nanotechnology mainly encompasses with biology, physics, chemistry and material sciences and it develops novel therapeutic nanosized materials for biomedical and pharmaceutical applications. The biological syntheses of nanoparticles are being carried out by different macro-microscopic organisms such as plant, bacteria, fungi, seaweeds and microalgae. The biosynthesized nanomaterials have been effectively controlling the various endemic diseases with less adverse effect. Plant contains abundant natural compounds such as alkaloids, flavonoids, saponins, steroids, tannins and other nutritional compounds. These natural products are derived from various parts of plant such as leaves, stems, roots shoots, flowers, barks, and seeds. Recently, many studies have proved that the plant extracts act as a potential precursor for the synthesis of nanomaterial in non-hazardous ways. Since the plant extract contains various secondary metabolites, it acts as reducing and stabilizing agents for the bioreduction reaction to synthesized novel metallic nanoparticles. The non-biological methods (chemical and physical) are used in the synthesis of nanoparticles, which has a serious hazardous and high toxicity for living organisms. In addition, the biological synthesis of metallic nanoparticles is inexpensive, single step and eco-friendly methods. The plants are used successfully in the synthesis of various greener nanoparticles such as cobalt, copper, silver, gold, palladium, platinum, zinc oxide and magnetite. Also, the plant mediated nanoparticles are potential remedy for various diseases such as malaria, cancer, HIV, hepatitis and other acute diseases.
  6. Ishak NH, Mohd Yusoff SS, Rahman RA, Kadir AA
    J Taibah Univ Med Sci, 2017 Dec;12(6):504-511.
    PMID: 31435286 DOI: 10.1016/j.jtumed.2017.03.008
    OBJECTIVES: Diabetes is a primarily self-manageable condition. Healthcare professionals usually offer education, treatment, and support, but patients themselves are responsible for the daily management of their condition. Increasing the effectiveness of self-management support may have a considerable impact on health care, especially for elderly people. The aim of this study was to describe diabetes self-care among elderly diabetics and to determine its associated factors.
    METHODS: This report describes a cross-sectional study involving 143 elderly diabetes patients in the outpatient department of the Hospital Universiti Sains Malaysia (HUSM). Self-care activities assessed in this study included dietary control, physical activity, self-monitoring of blood glucose, medication adherence, and situational related adherence behaviour, all of which were obtained using the validated Malay Elderly Diabetes Self-Care Questionnaire (MEDSCaQ).
    RESULTS: The mean (±SD) age of the subjects was 67.9 (±5.4) years old. A majority was Malay, with a mean HbA1c of 8.4 (±1.9). The mean diabetes self-care score was 26.5 (±8.0). Factors with a positive impact on diabetes self-care included being non-Malay (β = 5.275, p = 0.002), having family as care givers (β = 8.995, p = 0.004), having a higher level of family support (β = 0.159, p = 0.042), and possessing acceptable (β = 4.375, p = 0.001) or good knowledge of diabetes (β = 5.893, p = 0.004). The presence of neuropathy negatively impacted self-care, while diabetes nephropathy had a positive impact on self care (β = -4.053, p = 0.003).
    CONCLUSIONS: Elderly individuals with type 2 diabetes in HUSM have a moderate score of diabetes self-care practice based on the MEDSCaQ. Determinants for good diabetes self-care include race, social support, having care-takers during periods of illness, diabetes knowledge, and diabetic microvascular complications.
    Study site: outpatient department, Hospital Universiti Sains Malaysia (HUSM), Kelantan, Malaysia
  7. Jane Ling MY, Ahmad N, Mohd Yusoff MF, Lim KH
    PLoS One, 2022;17(1):e0263355.
    PMID: 35100321 DOI: 10.1371/journal.pone.0263355
    BACKGROUND: Adolescent e-cigarette use has increased dramatically. Most e-cigarette liquids contain nicotine, which can harm the developing adolescent brain. Local studies examining the risk factors of adolescent e-cigarette use and interactions between its risk factors are limited. This study was aimed at determining the prevalence of current e-cigarette use and its associated factors among in-school adolescents in West Malaysia. We also examined the possible sociodemographic characteristic, lifestyle risk behaviour and parental factor interactions that affect the probability of current e-cigarette use.

    METHODS: We conducted a cross-sectional study using data from the National Health and Morbidity Survey 2017. Respondents aged 13-18 years were included in the study. The data were analysed using STATA (v.15).

    RESULTS: The prevalence of current e-cigarette use was 9.1%. Male gender, older age, Malay ethnicity, schooling in urban area, current smoking, current alcohol use, current drug use, having parents that are not married and living together and parental tobacco product use were significantly associated with current e-cigarette use. There were significant interactions between: i) gender with age, ethnicity, current smoking, current alcohol use and current drug use, ii) ethnicity with current smoking and current alcohol use, iii) locality with ethnicity, current smoking and current alcohol use, iv) current drug use with age, ethnicity, current smoking and current alcohol use, v) parental marital status with gender, age and ethnicity, and vi) parental tobacco use with ethnicity and current smoking.

    CONCLUSION: Our findings identify significant associations between sociodemographic characteristics, lifestyle risk behaviours and parental factors with current e-cigarette use. They also provide new insight into the interactions between these factors that affect the probability of current e-cigarette use among West Malaysian adolescents. Efforts to tackle e-cigarette use in Malaysian adolescents should target sociodemographic characteristics, lifestyle risk behaviours and parental factors such as smoking cessation intervention for parents.
  8. Al-Jadi AM, Kanyan Enchang F, Mohd Yusoff K
    Turk J Med Sci, 2014;44(5):733-40.
    PMID: 25539538
    BACKGROUND/AIM: To examine, for the first time, the effect of a selected Malaysian honey and its major components on the proliferation of cultured fibroblasts.

    MATERIALS AND METHODS: Honey and some of its components, which include the sugars, the proteins, the hydrogen peroxide produced, and the phenolics, were exposed to cultured fibroblasts. The MTT colorimetric assay was used to assess cell viability and proliferation.

    RESULTS: The stimulatory effect of honey on fibroblast proliferation was observed to be time- and dose-dependent. The continuous production of hydrogen peroxide by the honey-glucose oxidase system also acts to stimulate cell proliferation in a time- and dose-dependent manner. The presence of phenolics with antioxidant properties, on the other hand, renders protection to the cells against the toxic effect of hydrogen peroxide. However, the presence of a growth factor-like substance in honey could not be ascertained.

    CONCLUSION: For the first time, honey and its major components were shown to exert stimulatory effects on cultured fibroblasts. Honey is therefore potentially useful in medicinal practices.

  9. Damulira E, Yusoff MNS, Omar AF, Mohd Taib NH
    Phys Med Biol, 2021 Apr 12;66(8).
    PMID: 33725685 DOI: 10.1088/1361-6560/abef44
    Light-emitting diodes (LEDs) could be a potential dosimetry candidate because they are radiation hard, spectrally selective, direct band gap, and low-cost devices. Thus, an LED-based detector prototype was designed and characterized for dosimetry. A 20 × 20 cm2array of surface mount device LED chips was sandwiched in photovoltaic mode between two intensifying screens to form a dosimetric system. The system was enclosed in a light-tight air cavity using black vinyl tape. The screens converted diagnostic x-ray beams into fluorescent blue light. LEDs, applied in detector mode, converted the fluorescent light into radiation-induced currents. A digital multimeter converted the analog currents into digital voltage signals. Prototype characterization was executed using (a) IEC 61267's RQR 7 (90 kVp) and RQR 8 (100 kVp) beam qualities, and (b) low (25 mAs) and high (80 mAs) beam quantities. A standard dosimeter probe was simultaneously exposed with the prototype to measure the prototype's absorbed dose. In all exposures, the x-ray beams were perpendicularly incident on both the dosimeter and prototype, at a fixed source to detector distance-60 cm. The LED array prototype's minimum detectable dose was 0.139 mGy, and the maximum dose implemented herein was ∼13 mGy. The prototype was 99.18% and 98.64% linearly sensitive to absorbed dose and tube current-time product (mAs), respectively. The system was ±4.69% energy, ±6.8% dose, and ±7.7% dose rate dependent. Two prototype data sets were 89.93% repeatable. We fabricated an ultrathin (5 mm), lightweight (130 g), and a relatively low-cost LED-based dosimetric prototype. The prototype executed a simple, efficient, and accurate real-time dosimetric mechanism. It could thus be an alternative to the current passive dosimetric systems.
  10. Ahmed Z, Yusoff MS, N H MK, Abdul Aziz H
    J Air Waste Manag Assoc, 2022 01;72(1):116-130.
    PMID: 33872123 DOI: 10.1080/10962247.2021.1919240
    A massive quantity of Elaeis guineensis (oil palm) trunk biomass, containing a significant amount of natural starch, is available in Malaysia as biowaste because of annual replantation. The efficient extraction of this starch (carbohydrate polymer) would be worthwhile concerning the environmental sustainability and economy through conversion to bioresources. This study investigated the effectiveness of the bisulfite steeping method for starch synthesis from oil palm trunk (OPT) biowaste. The central composite design (CCD) of Design-Expert software executed an experimental model design, data analysis, evaluated the impacts of process variables and their interaction through response surface methodology to optimize the bisulfite steeping method for starch synthesis. The developed quadratic models for four factors (strength of sodium bisulfite solution, steeping hour, mixing ratio with the bisulfite solution, and ultrapure water) and one response (%Yield) demonstrated that a significant starch yield (13.54%) is achievable employing 0.74% bisulfite solution, 5.6 steeping hours, for 1.6 and 0.6 mixing ratio with the bisulfite solution and ultrapure water respectively. Experimental outcomes were consistent with the predicted model, which eventually sustains the significance of this method. Malvern Zetasizer test revealed a bimodal granular distribution for starch, with 7.15 µm of hydrodynamic size. Starch morphology was determined by scanning electron microscopy. X-ray diffraction investigation exhibits an A-type model, specifying persistent characteristics, while FTIR confirms the presence of hydroxyl, carboxylic, and phenolic groups like other cereal starches.Implications: Malaysia is the 2nd largest palm oil exporter in the world. About 110 million tons of palm oil trunk (OPT) biomass is available annually during replanting activities. Modification of bio-wastes into a beneficial form (only 22% presently) like starch extraction would ensure potential reuse as a natural coagulant for wastewater and leachate treatment, food source, adhesives towards boosting the country's economy by sustainable waste management. The current study achieved better starch yield (13.54%) than previous, from the OPT biomass through the novel bisulfite steeping method. Therefore, this method will ascertain the effective implication of numerous economic activities.
  11. Yusoff YM, Abbott G, Young L, Edrada-Ebel R
    Metabolites, 2022 Jan 17;12(1).
    PMID: 35050207 DOI: 10.3390/metabo12010085
    This study aims to compare the metabolomic profiles of Malaysian and New Zealand honey while determining their anti-oncogenic activity for potential prophylactic functions. Metabolomics tools including multivariate analysis were applied on concatenated LC-HRMS and NMR datasets to afford an intensive chemical profile of honey samples and have a snapshot of the bioactive metabolites in the respective collections. Malaysian samples were found to have higher sugar and polyphenolic content, while New Zealand samples afforded higher concentration of low molecular weight (MW) lipids. However, New Zealand honey collected from the northern islands had higher concentration of acetylated saccharides, while those from the southern islands yielded higher low MW phenolic metabolites that were comparable to Malaysian honey. Mild anti-oncogenic compounds against breast cancer cell line ZR75 were putatively identified in Malaysian honey that included earlier described antioxidants such as gingerdiol, 2-hexylphenol-O-β-D-xylopyranoside, plastoquinone, tropine isovalerate, plumerinine, and 3,5-(12-phenyl-8-dodecenyl)resorcinol, along with several phenolic esters and lignans.
  12. Yusoff NHM, Hassan Z, Murugaiyah V, Müller CP
    Brain Res Bull, 2022 01;178:1-8.
    PMID: 34774992 DOI: 10.1016/j.brainresbull.2021.11.002
    Kratom, derived from the plant Mitragyna speciosa (M. speciosa) Korth is a traditional psychoactive preparation widely used in Southeast Asia and increasingly in the rest of the world. Use and abuse of Kratom preparations can be attributed to mitragynine (MIT), the main psychoactive compound isolated from its leaves. While MIT may have beneficial effects as a recreational drug, for pain management, and for opiate withdrawal, it may have an addiction potential at higher doses. However, its action in the reward system of the brain is currently unknown. This study investigated how mitragynine (10 mg/kg, i.p.) affects extracellular activity of dopamine (DA) and its metabolites, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in the prefrontal cortex (PFC), nucleus accumbens (NAc) and caudate putamen (CPu) of the brain, compared to morphine (MOR; 10 mg/kg, i.p.) and methamphetamine (METH; 10 mg/kg, i.p.). Using in-vivo microdialysis in freely moving rats, we found a significant increase of extracellular DA after MOR and METH, but not after MIT in all three brain regions. MIT led to a significant increase of DOPAC and/or HVA in these brain regions while MOR and METH had only moderate effects. These findings suggest a strong and prolonged effect of MIT on DA synthesis/metabolism, but not on extracellular DA activity, which may limit the addiction risk of MIT, in contrast to MOR and METH.
  13. Arshad A, Amani AA, Amin SMN, Yusoff FM
    J Environ Biol, 2016 07;37(4 Spec No):709-13.
    PMID: 28779730
    Parapenaeopsis sculptilis (Heller, 1862) locally referred to as ?udang kulit keras? in Malaysia has profound biological, ecological, aquacultural and conservational significance. The reproductive biology of this important penaeid from the coastal waters of Perak, Peninsular Malaysia, was studied during the period between February 2012 to January 2013. Females outnumbered males with a sex ratio of M: F= 1:3 (P < 0.05). Four maturity stages of female gonads viz., immature, maturing, mature and spent stages were distinguished. The first stage of sexual maturity was attained at a length of 9.3 cm, and female P. sculptilis showed a peak gonadosomatic index during the month of April, August and October, indicating that P. sculptilis potentially breeds throughout the year. The findings of this study would greatly contribute towards the understanding of gonadal maturation, spawning season and breeding biology, which could be important for the effective population management of this prawn species.
  14. Mohamed N, Saddki N, Yusoff A, Mat Jelani A
    BMC Oral Health, 2017 Aug 22;17(1):119.
    PMID: 28830386 DOI: 10.1186/s12903-017-0409-y
    BACKGROUND: Health-related quality of life (HRQOL) is a multidimensional construct that refers to an individual's self-perceived well-being. This study used the revised Wilson and Cleary HRQOL model to investigate the associations among oral symptoms, oral health-related quality of life (OHRQOL), and HRQOL of people living with HIV/AIDS (PLWHA) in Malaysia.

    METHODS: A total of 121 PLWHA receiving medical care in Kota Bharu (Kelantan, Malaysia) participated in this cross-sectional study. The Malay version of the short Oral Health Impact Profile (S-OHIP(M)) and the Malay version of the 36-item Medical Outcome Study Short Form (SF-36) were used to assess OHRQOL and HRQOL, respectively. A higher S-OHIP(M) score indicates greater oral impact and worse OHRQOL; a higher SF-36 score indicates better HRQOL. An additional structured self-administered questionnaire was used to obtain other variables of interest from the participants.

    RESULTS: Most participants had at least one oral symptom (69.4%), and the most common oral symptom was a cavitated tooth (55.4%). The prevalence of oral impacts was 33.9%, and the mean S-OHIP(M) score was 8.8 (SD = 7.92). The mean S-OHIP(M) score was significantly higher in participants who had toothaches, cavitated teeth, gum abscesses, and bad breath. In addition, participants with lower S-OHIP(M) scores had significantly higher scores in all SF-36 domains.

    CONCLUSIONS: Our study provides evidence for an association among oral symptoms, OHRQOL, and HRQOL in PLWHA from Malaysia. In particular, the presence of oral symptoms was significantly associated with more severe oral impacts and poorer OHRQOL. The presence of less severe oral impacts was associated with a better HRQOL.

  15. Kuppusamy P, Govindan N, Yusoff MM, Ichwan SJA
    Saudi J Biol Sci, 2017 Sep;24(6):1212-1221.
    PMID: 28855814 DOI: 10.1016/j.sjbs.2014.09.017
    Colon cancer is the most common type of cancer and major cause of death worldwide. The detection of colon cancer is difficult in early stages. However, the secretory proteins have been used as ideal biomarker for the detection of colon cancer progress in cancer patients. Serum/tissue protein expression could help general practitioners to identify colon cancer at earlier stages. By this way, we use the biomarkers to evaluate the anticancer drugs and their response to therapy in cancer models. Recently, the biomarker discovery is important in cancer biology and disease management. Also, many measurable specific molecular components have been studied in colon cancer therapeutics. The biomolecules are mainly DNA, RNA, metabolites, enzymes, mRNA, aptamers and proteins. Thus, in this review we demonstrate the important protein biomarker in colon cancer development and molecular identification of protein biomarker discovery.
  16. Yeo PS, Shahar S, Rajikan R, Mohd Yusoff NA
    Int J Public Health Res, 2014;4St(1):399-404.
    MyJurnal
    Introduction Low bone mineral density is a significant problem in children with Thalassemia which may lead to increased risk for fragility fractures and suboptimal peak bone mass. This cross-sectional study was conducted to
    determine the bone health status of Thalassemia children Universiti Kebangsaan Malaysia Medical Centre and Paediatrics Insititute Kuala Lumpur Hospital.
    Methods A total of 81 respondents diagnosed with transfusion dependant beta Thalassemia (41 boys and 40 girls) aged between 7 to 19 years old completed the study. The data collected were demographic information, anthropometric measurements, dairy frequency questionnaires, dietary habits of the respondents and their parents, dietary intakes and bone densitometry using Ultrasound Bone Densitometer.
    Results For Quantitative Ultrasound (QUS) parameters, T-score of 9.8% participants were lower than -1.0 and 30.9% of the participants had lower Speed of Sound (SOS) than healthy SOS. This study showed there was no difference in bone density by sex (p>0.05). The median bone density of boys was 1616.00 m/sec (IQR= 39.00) and girls’ was 1579.00 m/ sec (IQR= 116.00). SOS was not increased with age, height and weight; but girls’ Body Mass Index (BMI). Malay children had significantly higher SOS than non-Malay children.
    Conclusions This study highlights a need of proper intervention for the high risk group to achieve optimal bone health.
    Study site: inpatient or outpatient, Institut Pediatrik (Hospital Kuala Lumpur), Pusat Perubatan Universiti Kebangsaan Malaysia (PPUKM), Kuala Lumpur, Malaysia
  17. Yusoff NHM, Mansor SM, Müller CP, Hassan Z
    Behav Brain Res, 2018 06 01;345:65-71.
    PMID: 29499286 DOI: 10.1016/j.bbr.2018.02.039
    Mitragynine is the major alkaloid found in the leaves of M. speciosa Korth (Rubiaceae), a plant that is native to Southeast Asia. This compound has been used, either traditionally or recreationally, due to its psychostimulant and opioid-like effects. Recently, mitragynine has been shown to exert conditioned place preference (CPP), indicating the rewarding and motivational properties of M. speciosa. Here, the involvement of GABAB receptors in mediating mitragynine reward is studied using a CPP paradigm in rats. First, we examined the effects of GABAB receptor agonist baclofen (1.25, 2.5 and 5 mg/kg) on the acquisition of mitragynine (10 mg/kg)-induced CPP. Second, the involvement of GABAB receptors in the expression of mitragynine-induced CPP was tested. We found that the acquisition of mitragynine-induced CPP could be blocked by higher doses (2.5 and 5 mg/kg) of baclofen. Baclofen at a high dose inhibited locomotor activity and caused a CPP. Furthermore, we found that baclofen (2.5 and 5 mg/kg) also blocked the expression of mitragynine-induced CPP. These findings suggest that both, the acquisition and expression of mitragynine's reinforcing properties is controlled by the GABAB receptor.
  18. Ab-Murat N, Mason L, Kadir RA, Yusoff N
    Int J Occup Saf Ergon, 2018 Jun;24(2):233-239.
    PMID: 28010176 DOI: 10.1080/10803548.2016.1268869
    PURPOSE: To assess Malaysian dentists' perceptions of their mental well-being.

    METHODS: A self-administered questionnaire was developed based on a conceptual framework of mental health and well-being model. Two aspects were assessed, namely the physiological (two domains) and the psychological (six domains). Participants were asked to rate their experiences of the aforementioned aspects using a 5-point Likert scale ranging from all the time to never.

    RESULTS: The response rate was 81%. Most of the dentists (61.7%) perceived having positive mental well-being. Under the physiological aspect, most respondents reported that they were 'generally happy' (93.3%), but about 30% stated they were 'stressed physically and emotionally'. Of the six domains under the psychological aspect, positive well-being was observed in the 'sense of coherence' and 'behavioural stress' domains. Participants who were above 40 years old, married and had children reported having a more positive mental well-being when compared with their counterparts.

    CONCLUSION: Overall, most Malaysian dentists perceived having a positive mental well-being. It is crucial, however, to closely monitor and initiate early interventions for those with negative symptoms to ensure the safe practice of dentistry.

  19. Yusoff NHM, Mansor SM, Müller CP, Hassan Z
    Behav Brain Res, 2017 08 14;332:1-6.
    PMID: 28559179 DOI: 10.1016/j.bbr.2017.05.059
    Mitragynine is the main psychoactive ingredient of the herbal drug preparation Kratom (Ketum), derived from the plant Mitragyna speciosa. Kratom is a widely abused drug in Southeast Asian and has a psychostimulant profile at low-medium doses, while high doses have opioidergic effects. Mitragynine was shown to possess opiate receptor affinity. However, its role in the behavioural effects of mitragynine is unclear. Here we asked whether the reinforcing effects of mitragynine are mediated by opiate receptors using a conditioned place preference (CPP) paradigm in rats. In the first experiment we tested the effects of the opiate receptor antagonist naloxone (0.1, 0.3 and 1.0mg/kg) on the acquisition of mitragynine (10mg/kg)-induced CPP. In the second experiment, we tested the involvement of opiate receptors in the expression of mitragynine-induced CPP in rats. We found that naloxone suppresses the acquisition of mitragynine-induced CPP. This effect was already evident at a dose of naloxone (0.1mg/kg) which, by itself, had no conditioned place aversion (CPA) effect. Higher doses of naloxone induced a CPA and blocked mitragynine-induced CPP. In contrast, naloxone had no effect on the expression of mitragynine-induced CPP. These findings suggest that the acquisition, but not the expression of the reinforcing effects of mitragynine is mediated by opiate receptors.
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