Displaying publications 1 - 20 of 841 in total

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  1. Mohd Nazry Salleh, Farizul Hafiz Kasim, Khairul Nizar Ismail, Che Mohd Ruzaidi Ghazali, Kamarudin Hussin, Saiful Azhar Saad, et al.
    MyJurnal
    Batu Reput’ is primary sediment mineral and abundantly found in Perlis. Perlis is one of the major producers of ‘Batu Reput’ in Malaysia that content large deposit of high-purity dolomite [CaMg (CO3)2]. Pure samples of ‘Batu Reput’ recently explored in the Koperasi Rimba Mas Padang Besar Quarry were investigated for their physical, chemical and mineralogical composition. SEM and XRD analysis methods were applied. The potential of ‘Batu Reput’ as a raw material in fertilizer production was investigated in this paper.
    Matched MeSH terms: Calcium Carbonate
  2. Ngadiman NH, Idris A, Irfan M, Kurniawan D, Yusof NM, Nasiri R
    J Mech Behav Biomed Mater, 2015 Sep;49:90-104.
    PMID: 26002419 DOI: 10.1016/j.jmbbm.2015.04.029
    Maghemite (γ-Fe2O3) nanoparticle with its unique magnetic properties is recently known to enhance the cell growth rate. In this study, γ-Fe2O3 is mixed into polyvinyl alcohol (PVA) matrix and then electrospun to form nanofibers. Design of experiments was used to determine the optimum parameter settings for the electrospinning process so as to produce elctrospun mats with the preferred characteristics such as good morphology, Young's modulus and porosity. The input factors of the electrospinnning process were nanoparticles content (1-5%), voltage (25-35 kV), and flow rate (1-3 ml/h) while the responses considered were Young's modulus and porosity. Empirical models for both responses as a function of the input factors were developed and the optimum input factors setting were determined, and found to be at 5% nanoparticle content, 35 kV voltage, and 1 ml/h volume flow rate. The characteristics and performance of the optimum PVA/γ-Fe2O3 nanofiber mats were compared with those of neat PVA nanofiber mats in terms of morphology, thermal properties, and hydrophilicity. The PVA/γ-Fe2O3 nanofiber mats exhibited higher fiber diameter and surface roughness yet similar thermal properties and hydrophilicity compared to neat PVA PVA/γ-Fe2O3 nanofiber mats. Biocompatibility test by exposing the nanofiber mats with human blood cells was performed. In terms of clotting time, the PVA/γ-Fe2O3 nanofibers exhibited similar behavior with neat PVA. The PVA/γ-Fe2O3 nanofibers also showed higher cells proliferation rate when MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was done using human skin fibroblast cells. Thus, the PVA/γ-Fe2O3 electrospun nanofibers can be a promising biomaterial for tissue engineering scaffolds.
    Matched MeSH terms: Calcium Chloride/pharmacology
  3. Kausar S, Altaf AA, Hamayun M, Rasool N, Hadait M, Akhtar A, et al.
    Molecules, 2020 Jul 31;25(15).
    PMID: 32752133 DOI: 10.3390/molecules25153520
    Lignin depolymerization for the purpose of synthesizing aromatic molecules is a growing focus of research to find alternative energy sources. In current studies, the photocatalytic depolymerization of lignin has been investigated by two new iso-propylamine-based lead chloride perovskite nanomaterials (SK9 and SK10), synthesized by the facile hydrothermal method. Characterization was done by Powder X-Ray Diffraction (PXRD), Scanning Electron Microscopy (SEM), UV-Visible (UV-Vis), Photoluminescence (PL), and Fourier-Transform Infrared (FTIR) Spectroscopy and was used for the photocatalytic depolymerization of lignin under UV light. Lignin depolymerization was monitored by taking absorption spectra and catalytic paths studied by applying kinetic models. The %depolymerization was calculated for factors such as catalyst dose variation, initial concentration of lignin, and varying temperatures. Pseudo-second order was the best suited kinetic model, exhibiting a mechanism for lignin depolymerization that was chemically rate controlled. The activation energy (Ea) for the depolymerization reaction was found to be 15 kJ/mol, which is remarkably less than conventional depolymerization of the lignin, i.e., 59.75 kJ/mol, exhibiting significant catalytic efficiencies of synthesized perovskites. Products of lignin depolymerization obtained after photocatalytic activity at room temperature (20 °C) and at 90 °C were characterized by GC-MS analysis, indicating an increase in catalytic lignin depolymerization structural subunits into small monomeric functionalities at higher temperatures. Specifically, 2-methoxy-4-methylphenol (39%), benzene (17%), phenol (10%) and catechol (7%) were detected by GC-MS analysis of lignin depolymerization products.
    Matched MeSH terms: Calcium Compounds/chemistry*
  4. Subach OM, Vlaskina AV, Agapova YK, Korzhenevskiy DA, Nikolaeva AY, Varizhuk AM, et al.
    Int J Mol Sci, 2022 Nov 23;23(23).
    PMID: 36498942 DOI: 10.3390/ijms232314614
    NTnC-like green fluorescent genetically encoded calcium indicators (GECIs) with two calcium ion binding sites were constructed using the insertion of truncated troponin C (TnC) from Opsanus tau into green fluorescent proteins (GFPs). These GECIs are small proteins containing the N- and C-termini of GFP; they exert a limited effect on the cellular free calcium ion concentration; and in contrast to calmodulin-based calcium indicators they lack undesired interactions with intracellular proteins in neurons. The available TnC-based NTnC or YTnC GECIs had either an inverted response and high brightness but a limited dynamic range or a positive response and fast kinetics in neurons but lower brightness and an enhanced but still limited dF/F dynamic range. Here, we solved the crystal structure of NTnC at 2.5 Å resolution. Based on this structure, we developed positive NTnC2 and inverted iNTnC2 GECIs with a large dF/F dynamic range in vitro but very slow rise and decay kinetics in neurons. To overcome their slow responsiveness, we swapped TnC from O. tau in NTnC2 with truncated troponin C proteins from the muscles of fast animals, namely, the falcon, hummingbird, cheetah, bat, rattlesnake, and ant, and then optimized the resulting constructs using directed molecular evolution. Characterization of the engineered variants using purified proteins, mammalian cells, and neuronal cultures revealed cNTnC GECI with truncated TnC from Calypte anna (hummingbird) to have the largest dF/F fluorescence response and fast dissociation kinetics in neuronal cultures. In addition, based on the insertion of truncated TnCs from fast animals into YTnC2, we developed fYTnC2 GECI with TnC from Falco peregrinus (falcon). The purified proteins cNTnC and fYTnC2 had 8- and 6-fold higher molecular brightness and 7- and 6-fold larger dF/F responses to the increase in Ca2+ ion concentration than YTnC, respectively. cNTnC GECI was also 4-fold more photostable than YTnC and fYTnC2 GECIs. Finally, we assessed the developed GECIs in primary mouse neuronal cultures stimulated with an external electric field; in these conditions, cNTnC had a 2.4-fold higher dF/F fluorescence response than YTnC and fYTnC2 and was the same or slightly slower (1.4-fold) than fYTnC2 and YTnC in the rise and decay half-times, respectively.
    Matched MeSH terms: Calcium Signaling
  5. Ismail KS, Sakamoto T, Hasunuma T, Zhao XQ, Kondo A
    Biotechnol J, 2014 Dec;9(12):1519-25.
    PMID: 24924214 DOI: 10.1002/biot.201300553
    Lignocellulosic biomass is a potential substrate for ethanol production. However, pretreatment of lignocellulosic materials produces inhibitory compounds such as acetic acid, which negatively affect ethanol production by Saccharomyces cerevisiae. Supplementation of the medium with three metal ions (Zn(2+) , Mg(2+) , and Ca(2+) ) increased the tolerance of S. cerevisiae toward acetic acid compared to the absence of the ions. Ethanol production from xylose was most improved (by 34%) when the medium was supplemented with 2 mM Ca(2+) , followed by supplementation with 3.5 mM Mg(2+) (29% improvement), and 180 μM Zn(2+) (26% improvement). Higher ethanol production was linked to high cell viability in the presence of metal ions. Comparative transcriptomics between the supplemented cultures and the control suggested that improved cell viability resulted from the induction of genes controlling the cell wall and membrane. Only one gene, FIT2, was found to be up-regulated in common between the three metal ions. Also up-regulation of HXT1 and TKL1 might enhance xylose consumption in the presence of acetic acid. Thus, the addition of ionic nutrients is a simple and cost-effective method to improve the acetic acid tolerance of S. cerevisiae.
    Matched MeSH terms: Calcium/pharmacology*
  6. Mostak Ahmed, Noorlidah Abdullah, Nuruddin MM
    Sains Malaysiana, 2016;45:1609-1615.
    In recent decades, minimizing the frequency of nutrient deficiency and malnutrition in rural areas of developing
    countries becomes an alarming issue. Oyster mushrooms are rich source of both macro and micro nutrients. The
    objective of this paper was to evaluate the yield of newly introduced oyster mushroom strains viz. Pleurotus sajorcaju
    (PSC), Pleurotus flabellatus (FLB), Pleurotus florida (FLO), Pleurotus ostreatus (PO2
    and PO3
    ), Pleurotus ostreatus
    (HK-51) and Pleurotus geesteranus (PG1
    and PG3
    ) and to justify their nutritional values when grown in the climatic
    condition of Bangladesh. Strain HK-51 produced the highest amount of fresh sporophore (197.80 g). In contrast, the
    highest number of fruiting body was obtained from the strain FLO (82 g) followed by strain PSC (69 g). Strain PG1 has
    recorded the highest biological yield (278 g), productivity (55%) and biological efficiency (96%). Nutrient and mineral
    analysis of sporophore of strain PG1 showed protein (31.80%), lipid (3.6%), potassium (1.3 mg/100 g), phosphorus
    (0.8 mg/100 g), calcium (32 mg/100 g), iron (43 mg/100 g), magnesium (12 mg/100 g), copper (3.5 mcg/100 g), zinc
    (12.5 mcg/100 g) and manganese (2.3 mcg/100 g). This study showed that the strain PG1
    performed well with regard to
    quality and productivity as compared to other strains. Hence, oyster mushroom strain PG1
    is a potential cheap source
    of nutrients and minerals to combat socioeconomic problems including malnutrition, diseases linked to malnutrition,
    poverty reduction and agricultural diversity.
    Matched MeSH terms: Calcium, Dietary
  7. Tiang N, Ahad MA, Murugaiyah V, Hassan Z
    J Pharm Pharmacol, 2020 Nov;72(11):1629-1644.
    PMID: 32743849 DOI: 10.1111/jphp.13345
    OBJECTIVES: Xanthones isolated from the pericarp of Garcinia mangostana has been reported to exhibit neuroprotective effect.

    METHODS: In this study, the effect of xanthone-enriched fraction of Garcinia mangostana (XEFGM) and α-mangostin (α-MG) were investigated on cognitive functions of the chronic cerebral hypoperfusion (CCH) rats.

    KEY FINDINGS: HPLC analysis revealed that XEFGM contained 55.84% of α-MG. Acute oral administration of XEFGM (25, 50 and 100 mg/kg) and α-MG (25 and 50 mg/kg) before locomotor activity and Morris water maze (MWM) tests showed no significant difference between the groups for locomotor activity.

    CONCLUSIONS: However, α-MG (50 mg/kg) and XEFGM (100 mg/kg) reversed the cognitive impairment induced by CCH in MWM test. α-MG (50 mg/kg) was further tested upon sub-acute 14-day treatment in CCH rats. Cognitive improvement was shown in MWM test but not in long-term potentiation (LTP). BDNF but not CaMKII was found to be down-regulated in CCH rats; however, both parameters were not affected by α-MG. In conclusion, α-MG ameliorated learning and memory deficits in both acute and sub-acute treatments in CCH rats by improving the spatial learning but not hippocampal LTP. Hence, α-MG may be a promising lead compound for CCH-associated neurodegenerative diseases, including vascular dementia and Alzheimer's disease.

    Matched MeSH terms: Calcium-Calmodulin-Dependent Protein Kinase Type 2/metabolism
  8. Kamaruddin FA, Anggraini V, Kim Huat B, Nahazanan H
    Materials (Basel), 2020 Jun 17;13(12).
    PMID: 32560432 DOI: 10.3390/ma13122753
    The durability of natural and treated clay soil stabilized with lime and alkaline activation (AA) affected by environmental factors (hot and humid) was determined in this study. Investigation and evaluation on the strength of the soil, moisture content, and volume change of the specimen were determined at each curing period (7, 28, and 90 days) based on the weather conditions. An unconfined compressive strength (UCS) of the specimen at three different wetting/drying cycles (one, three, and five cycles) was determined. The findings show that the strength of the treated specimens fluctuated with increment and decrement strength (one and three cycles) in the range of 1.41 to 1.88 MPa (lime) and 2.64 to 8.29 MPa (AA), while for five cycles with a curing period of 90 days the decrement was in the range of 1.62 to 1.25 MPa and 6.06 to 5.89 MPa for lime and AA, respectively. The decrement percentage for treated samples that were subjected to five cycles of wetting and drying in 90 days was found to be 20.38% (lime) and 38.64% (AA), respectively. Therefore, it can be summarized that wetting/drying cycles have a significant influence on the durability, strength, and the volume changes of the specimens.
    Matched MeSH terms: Calcium Compounds
  9. Leong HY, Chang CK, Khoo KS, Chew KW, Chia SR, Lim JW, et al.
    Biotechnol Biofuels, 2021 Apr 07;14(1):87.
    PMID: 33827663 DOI: 10.1186/s13068-021-01939-5
    Global issues such as environmental problems and food security are currently of concern to all of us. Circular bioeconomy is a promising approach towards resolving these global issues. The production of bioenergy and biomaterials can sustain the energy-environment nexus as well as substitute the devoid of petroleum as the production feedstock, thereby contributing to a cleaner and low carbon environment. In addition, assimilation of waste into bioprocesses for the production of useful products and metabolites lead towards a sustainable circular bioeconomy. This review aims to highlight the waste biorefinery as a sustainable bio-based circular economy, and, therefore, promoting a greener environment. Several case studies on the bioprocesses utilising waste for biopolymers and bio-lipids production as well as bioprocesses incorporated with wastewater treatment are well discussed. The strategy of waste biorefinery integrated with circular bioeconomy in the perspectives of unravelling the global issues can help to tackle carbon management and greenhouse gas emissions. A waste biorefinery-circular bioeconomy strategy represents a low carbon economy by reducing greenhouse gases footprint, and holds great prospects for a sustainable and greener world.
    Matched MeSH terms: Calcium Phosphates
  10. Bin Rafiq MKS, Amin N, Alharbi HF, Luqman M, Ayob A, Alharthi YS, et al.
    Sci Rep, 2020 Jan 21;10(1):771.
    PMID: 31964954 DOI: 10.1038/s41598-020-57596-5
    Radio frequency (RF) magnetron sputtering was used to deposit tungsten disulfide (WS2) thin films on top of soda lime glass substrates. The deposition power of RF magnetron sputtering varied at 50, 100, 150, 200, and 250 W to investigate the impact on film characteristics and determine the optimized conditions for suitable application in thin-film solar cells. Morphological, structural, and opto-electronic properties of as-grown films were investigated and analyzed for different deposition powers. All the WS2 films exhibited granular morphology and consisted of a rhombohedral phase with a strong preferential orientation toward the (101) crystal plane. Polycrystalline ultra-thin WS2 films with bandgap of 2.2 eV, carrier concentration of 1.01 × 1019 cm-3, and resistivity of 0.135 Ω-cm were successfully achieved at RF deposition power of 200 W. The optimized WS2 thin film was successfully incorporated as a window layer for the first time in CdTe/WS2 solar cell. Initial investigations revealed that the newly incorporated WS2 window layer in CdTe solar cell demonstrated photovoltaic conversion efficiency of 1.2% with Voc of 379 mV, Jsc of 11.5 mA/cm2, and FF of 27.1%. This study paves the way for WS2 thin film as a potential window layer to be used in thin-film solar cells.
    Matched MeSH terms: Calcium Compounds
  11. Zakaria S, Mat-Husain SZ, Ying-Hwey K, Xin-Kai K, Mohd-Badawi A, Abd-Ghani NA, et al.
    Iran J Basic Med Sci, 2017 Dec;20(12):1360-1367.
    PMID: 29238472 DOI: 10.22038/IJBMS.2017.9610
    Objectives: Alcohol consumption induces oxidative stress on bone, which in turn increases the risk of osteoporosis. This study determined the effects of vitamin E on bone strength and bone mineral content in alcohol-induced osteoporotic rats.

    Materials and Methods: Three months old Sprague Dawley male rats were randomly divided into 5 groups: (I) control group; (II) alcohol (3g/kg) + normal saline; (III) alcohol (3g/kg) + olive oil; (IV) alcohol (3g/kg) + alpha-tocopherol (60mg/kg) and (V) alcohol (3g/kg) + palm vitamin E (60mg/kg). The treatment lasted for three months. Following sacrifice, the right tibia was subjected to bone biomechanical test while the lumbar (fourth and fifth lumbar) and left tibia bones were harvested for bone mineral measurement.

    Results: Alcohol caused reduction in bone biomechanical parameters (maximum force, ultimate stress, yield stress and Young's modulus) and bone minerals (bone calcium and magnesium) compared to control group (P<0.05). Palm vitamin E was able to improve bone biomechanical parameters by increasing the maximum force, ultimate stress and Young's modulus (P<0.05) while alpha-tocopherol was not able to. Both alpha-tocopherol and palm vitamin E were able to significantly increase tibia calcium and magnesium content while only alpha-tocopherol caused significant increase in lumbar calcium content (P<0.05).

    Conclusion: Both palm vitamin E and alpha-tocopherol improved bone mineral content which was reduced by alcohol. However, only palm vitamin E was able to improve bone strength in alcohol treated rats.

    Matched MeSH terms: Calcium, Dietary
  12. Norazlina M, Chua CW, Ima-Nirwana S
    Med J Malaysia, 2004 Dec;59(5):623-30.
    PMID: 15889565
    Vitamin E deficiency has been found to impair bone calcification. This study was done to determine the effects of vitamin E deficiency and supplementation on parathyroid hormone, i.e. the hormone involved in bone regulation. Female Sprague-Dawley rats were divided into 4 groups: 1) normal rat chow (RC), 2) vitamin E deficiency (VED), vitamin E deficient rats supplemented with 3) 60 mg/kg alpha-tocotrienol (ATT) and 4) 60 mg/kg (alpha-tocopherol (ATF). Treatment was carried out for 3 months. Vitamin E deficiency caused hypocalcaemia during the first month of the treatment period, increased the parathyroid hormone level in the second month and decreased the bone calcium content in the 4th lumbar bone at the end of the treatment. Vitamin E supplementation (ATT and ATF) failed to improve these conditions. The bone formation marker, osteocalcin, and the bone resorption marker, deoxypyridinoline did not change throughout the study period. In conclusion vitamin E deficiency impaired bone calcium homeostasis with subsequent secondary hyperparathyroidism and vertebral bone loss. Replacing the vitamin E with pure ATF or pure ATT alone failed to correct the changes seen.
    Matched MeSH terms: Calcium/metabolism*
  13. Acharya M, Singh N, Gupta G, Tambuwala MM, Aljabali AAA, Chellappan DK, et al.
    Cell Signal, 2024 Apr;116:111043.
    PMID: 38211841 DOI: 10.1016/j.cellsig.2024.111043
    Calcium is a ubiquitous second messenger that is indispensable in regulating neurotransmission and memory formation. A precise intracellular calcium level is achieved through the concerted action of calcium channels, and calcium exerts its effect by binding to an array of calcium-binding proteins, including calmodulin (CAM), calcium-calmodulin complex-dependent protein kinase-II (CAMK-II), calbindin (CAL), and calcineurin (CAN). Calbindin orchestrates a plethora of signaling events that regulate synaptic transmission and depolarizing signals. Vitamin D, an endogenous fat-soluble metabolite, is synthesized in the skin upon exposure to ultraviolet B radiation. It modulates calcium signaling by increasing the expression of the calcium-sensing receptor (CaSR), stimulating phospholipase C activity, and regulating the expression of calcium channels such as TRPV6. Vitamin D also modulates the activity of calcium-binding proteins, including CAM and calbindin, and increases their expression. Calbindin, a high-affinity calcium-binding protein, is involved in calcium buffering and transport in neurons. It has been shown to inhibit apoptosis and caspase-3 activity stimulated by presenilin 1 and 2 in AD. Whereas CAM, another calcium-binding protein, is implicated in regulating neurotransmitter release and memory formation by phosphorylating CAN, CAMK-II, and other calcium-regulated proteins. CAMK-II and CAN regulate actin-induced spine shape changes, which are further modulated by CAM. Low levels of both calbindin and vitamin D are attributed to the pathology of Alzheimer's disease. Further research on vitamin D via calbindin-CAMK-II signaling may provide newer insights, revealing novel therapeutic targets and strategies for treatment.
    Matched MeSH terms: Calcium; Calcium-Binding Proteins; Calcium Channels; Calcium Signaling; Calcium-Calmodulin-Dependent Protein Kinase Type 2
  14. Ngai M, Lin V, Wong HC, Vathsala A, How P
    Clin. Nephrol., 2014 Oct;82(4):231-9.
    PMID: 25161115 DOI: 10.5414/CN108182
    BACKGROUND: Vitamin D deficiency is associated with secondary hyperparathyroidism and mineral and bone disorder (MBD) in chronic kidney disease (CKD). This study aimed to determine the prevalence of vitamin D insufficiency/deficiency, and the association between vitamin D status and MBD in a multi-ethnic CKD population in Southeast Asia.

    METHODS: Predialysis CKD patients were included in this cross-sectional study. Patient demographics, medical/medication histories, and laboratory parameters (serum 25-hydroxyvitamin D (25(OH)D), creatinine, phosphate (P), calcium, albumin, and intact-PTH (i-PTH)) were collected and compared among patients with various CKD stages. The association between 25(OH)D and these parameters was determined by multiple linear regression.

    RESULTS: A total of 196 patients with mean ± SD eGFR of 26.4 ± 11.2 mL/min/1.73 m2 was included. Vitamin D deficiency (25(OH)D concentration < 15 ng/mL) and insufficiency (25(OH)D concentration 16 - 30 ng/mL) was found in 29.1% and 57.7% of the patients, respectively. Mean ± SD serum 25(OH)D was 20.8 ± 9.3 ng/mL. Female patients had lower vitamin D concentrations than males (16.9 ng/mL vs. 23.9 ng/mL; p < 0.001). Vitamin D levels were also higher in Chinese (22.3 ng/mL) than Malay (17.3 ng/mL) and Indian (13.1 ng/mL) patients (p < 0.05). Nonadjusted analyses showed higher i-PTH concentration in vitamin D deficient patients (p < 0.05).

    CONCLUSION: Despite being a sun-rich country all year round, the majority (86.8%) of predialysis CKD patients in Singapore have suboptimal vitamin D status. Lower vitamin D concentrations were found in females and in those with darker skin tone. Vitamin D deficient patients also tended to have higher i-PTH levels.

    Matched MeSH terms: Calcium/blood
  15. Yeap SS, Othman AZ, Zain AA, Chan SP
    Int J Rheum Dis, 2012 Feb;15(1):17-24.
    PMID: 22324943 DOI: 10.1111/j.1756-185X.2011.01653.x
    AIM: To determine if baseline vitamin D levels would influence the gain in bone mineral density (BMD) in female systemic lupus erythematosus (SLE) patients on corticosteroids (CS) taking bone-active medication.

    METHOD: Premenopausal SLE patients participating in a trial assessing the efficacy of calcium alone, calcitriol and calcium, and alendronate and calcium, on BMD in patients on CS, were studied. Patients were randomly allocated to the treatment groups at the start of the study and followed up for 2 years. Serum 25-hydroxy vitamin D [25(OH)D] was measured at baseline.

    RESULTS:   Thirty-eight patients were studied. One (2%) patient had osteoporosis, nine (24%) had osteopenia and all others had normal BMD. The mean baseline 25(OH)D levels were 21.6 ± 4.6 ng/mL (± 1 SD). Twelve (32%) patients had vitamin D deficiency [25(OH)D < 20 ng/mL]. There was a significant negative correlation between SLEDAI scores and 25(OH)D levels, that is, patients with high SLEDAI scores had significantly lower 25(OH)D levels (P = 0.033). Left femoral neck BMD was significantly lower in the deficient compared to insufficient group (P = 0.042). There was a trend toward better BMD gain at 2 years in the vitamin D insufficient compared to the deficient group, which did not reach statistical significance.

    CONCLUSION: This study showed that in female SLE patients, low vitamin D levels are associated with higher disease activity and suggests that patients who have higher vitamin D levels have a better BMD response during treatment with bone-active agents.
    Matched MeSH terms: Calcium/therapeutic use
  16. Wee CL, Mokhtar SS, Banga Singh KK, Rasool AHG
    Microvasc Res, 2021 Nov;138:104227.
    PMID: 34324883 DOI: 10.1016/j.mvr.2021.104227
    This study examined the effects of vitamin D deficiency on vascular function and tissue oxidative status in the microcirculation; and whether or not these effects can be ameliorated with calcitriol, the active vitamin D metabolite. Three groups (n = 10 each) of male Sprague Dawley rats were fed for 10 weeks with control diet (CR), vitamin D-deficient diet without (DR), or with oral calcitriol supplementation (0.15 μg/kg) for the last four weeks (DSR). After 10 weeks, rats were sacrificed; mesenteric arterial rings were studied using wire myograph. Oxidative stress biomarkers malondialdehyde (MDA) levels and superoxide dismutase (SOD) activity were measured in the mesenteric arterial tissue. Vascular protein expression of endothelial nitric oxide synthase (eNOS) was determined by Western blotting. Acetylcholine-induced endothelium-dependent relaxation of DR was lower than CR. eNOS expression and SOD activity were lower in mesenteric arterial tissue of DR compared to CR. Calcitriol supplementation to DSR did not ameliorate the above parameters; in fact, augmented endothelium-dependent contraction was observed. Serum calcium was higher in DSR compared to CR and DR. In conclusion, vitamin D deficiency impaired microvascular vasodilation, associated with eNOS downregulation and reduced antioxidant activity. Calcitriol supplementation to vitamin D-deficient rats at the dosage used augmented endothelium-dependent contraction, possibly due to hypercalcaemia.
    Matched MeSH terms: Calcium/blood
  17. Wong SK, Chin KY, Ima-Nirwana S
    Curr Drug Targets, 2018;19(8):888-897.
    PMID: 28914205 DOI: 10.2174/1389450118666170913161030
    Depression is a common psychiatric disorder that decreases the quality of life and increases the mortality of patients. It incurs significant healthcare costs if left untreated. Even though intervention with antidepressants can reduce depressive symptoms, side effects are often an issue and relapse is very common. Vitamin D, commonly known as the sunshine vitamin, is an essential fat-soluble vitamin for the absorption of calcium to prevent rickets (children) and osteomalacia (adults). Evidence on a possible relationship between vitamin D deficiency and depression is growing. In this review, the authors summarized the evidence on the association between vitamin D status and depression in human observational studies, followed by clinical trials to evaluate the effects of vitamin D supplementation in treating depression. In conclusion, vitamin D deficiency may be associated with an increased risk or severity of depression. Supplementation of vitamin D may confer protection for depressed patients.
    Matched MeSH terms: Calcium/metabolism
  18. Suriawati AA, Majid HA, Al-Sadat N, Mohamed MN, Jalaludin MY
    Nutrients, 2016 Oct 24;8(10).
    PMID: 27783041
    BACKGROUND: Dietary calcium and vitamin D are essential for bone development. Apart from diet, physical activity may potentially improve and sustain bone health.

    OBJECTIVE: To investigate the relationship between the dietary intake of calcium and vitamin D, physical activity, and bone mineral content (BMC) in 13-year-old Malaysian adolescents.

    DESIGN: Cross-sectional.

    SETTING: Selected public secondary schools from the central and northern regions of Peninsular Malaysia.

    PARTICIPANTS: The subjects were from the Malaysian Health and Adolescents Longitudinal Research Team Cohort study (MyHeARTs).

    METHODS: The data included seven-day diet histories, anthropometric measurements, and the BMC of calcaneal bone using a portable broadband ultrasound bone densitometer. Nutritionist Pro software was used to calculate the dietary calcium and vitamin D intakes from the diet histories, based on the Nutrient Composition of Malaysian Food Database guidance for the dietary calcium intake and the Singapore Energy and Nutrient Composition of Food Database for vitamin D intake.

    RESULTS: A total of 289 adolescents (65.7% females) were recruited. The average dietary intakes of calcium and vitamin D were 377 ± 12 mg/day and 2.51 ± 0.12 µg/day, respectively, with the majority of subjects failing to meet the Recommended Nutrient Intake (RNI) of Malaysia for dietary calcium and vitamin D. All the subjects had a normal Z-score for the BMC (-2.00 or higher) with a mean of 0.55 ± 0.01. From the statistical analysis of the factors contributing to BMC, it was found that for those subjects with a higher intake of vitamin D, a higher combination of the intake of vitamin D and calcium resulted in significantly higher BMC quartiles. The regression analysis showed that the BMC might have been influenced by the vitamin D intake.

    CONCLUSIONS: A combination of the intake of vitamin D and calcium is positively associated with the BMC.

    Matched MeSH terms: Calcium, Dietary/analysis*
  19. Yikilmaz AŞ, Akinci S, Bakanay ŞM, Dilek İ
    Malays J Med Sci, 2020 Feb;27(1):70-77.
    PMID: 32158346 DOI: 10.21315/mjms2020.27.1.7
    Introduction: Vitamin D, which is known for its effects on calcium and bone metabolism, has recently been associated with haematological malignancies. We aimed to investigate the relationship between disease findings and vitamin D deficiency in essential thrombocythemia (ET) and polycythemia vera (PV).

    Material and Methods: This retrospective cohort study conducted in Turkey included 73 patients diagnosed with PV or ET according to WHO criteria between 2012 and 2018. Vitamin D deficiency was defined as 25-OH vitamin D < 20 ng/mL. Polymerase chain reaction (PCR) was used to detect the Janus kinase 2 (JAK2) V617F mutation.

    Results: Vitamin D deficiency was found in 66.7% of PV and 74.2% of ET patients. The median follow-up time of ET and PV patients was 48 months and 47 months, respectively. Patients with the JAK2 mutation had a higher prevalence of a history of thrombosis and age older than 65 years. There was a significant relationship between JAK2 positivity and vitamin D deficiency.

    Conclusion: There was a remarkably higher prevalence of vitamin D deficiency in JAK2 mutation-positive ET and PV patients. These patients should be carefully evaluated for vitamin D deficiency. More studies are required to further investigate the association between JAK2 and vitamin D.

    Matched MeSH terms: Calcium, Dietary
  20. Ho W, Lin Seow L, Musawi A
    J Clin Transl Res, 2018 May 28;4(1):70-74.
    PMID: 30873496
    Background: The purpose of the present study was to investigate the effect of different viscosities of polyvinyl siloxane (PVS) impression materials on the accuracy of the stone die produced.

    Methods: A three-unit bridge master model was fabricated using cold-cure acrylic resin. Four combinations of different viscosities of PVS impression materials - regular body (monophase) alone, light body with regular body, light body with heavy body, and light body with putty - were used to make an impression of the master model. Ten impressions from each group were taken and Type IV gypsum stone was used to generate the dies. The dies were measured at the inter-abutment distance, occlusogingival length, and shoulder width with a measuring microscope and were compared with the master model using one-way analysis of variance and Tukey (honest significant difference) test.

    Results: Differences were found for inter-abutment distance between the master model and the light body with regular body and light body with putty dies (both P < 0.02). A difference was found for shoulder width between the master model and the regular body alone die (P = 0.01). No differences were found for occlusogingival distance (all P > 0.08).

    Conclusion: Results suggested inter-abutment distance was most accurate when using a PVS light body combination. Occlusogingival length was accurate using any of the studied PVS combinations, and shoulder width was more accurate when using the regular body PVS.

    Relevance for patients: These results should be considered when choosing the viscosity of the PVS to use for producing impressions of high accuracy and fabricating a well-fitting fixed prosthesis.

    Matched MeSH terms: Calcium Sulfate
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