Displaying publications 41 - 60 of 189 in total

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  1. Field evaluation of newly-developed controlled release fertilizer on rice production and nitrogen uptake
    Mohammad Mu'az Hashim, Mohd Khanif Yusop, Radziah Othman, Samsuri Abd. Wahid
    Sains Malaysiana, 2017;46:925-932.
    Implementation of sound fertilizer management in rice cultivation is essential in optimizing productivity and profitability. The use of controlled release fertilizer (CRF) to improve crop production in various cropping systems has been widely explored, with new approaches and materials continually being studied to produce new CRF. A field study was carried out to determine the efficiency of local CRFs on rice production and N uptake using MR220 CL1 rice variety. Ten different types of CRFs consisting of two groups namely biochar impregnated urea (BIU 300-5, BIU 300-10, BIU 700-5 and BIU 700-10) and palm stearin (PS) coated urea with nitrification inhibitors (PS, PS+DMPP-100, PS+DMPP-50, PS+DMPP-150, PS+Cu and PS+Zn) were used as treatments. Plant height, SPAD reading, 1000-grain weight and harvest index (HI) showed significant improvement in rice treated with both biochar impregnated and palm stearin coated urea. With respect to grain yield, BIU 300-10, BIU 700-5, BIU 700-10, PS+DMPP-100, PS+DMPP-50, PS+DMPP-150 and PS+Cu treatments significantly increased rice yield. The CRFs mostly showed significantly higher N uptake in rice, especially in rice grains, however, there was no significant difference among treatments in soil residual ammonium (NH4+-N). The newly-developed CRFs showed huge potential as an alternative for common urea, especially BIU 700-5, BIU 700-10, PS+DMPP-100 and PS+DMPP-50, in increasing rice grain yield. With proper approaches, these CRFs can contribute in improving rice production to provide sufficient food for ever increasing population.
    Matched MeSH terms: Urea
  2. N-doped TiO2 synthesised via microwave induced photocatalytic on RR4 dye removal under LED light irradiation
    Azami MS, Nawawi WI, Ali H. Jawad, Ishak MAM, Azami MS, K. Ismail
    Sains Malaysiana, 2017;46:1390-1316.
    Nitrogen doped titanium dioxide (N-doped TiO2
    ) was synthesized by microwave using urea as nitrogen sources with
    commercially available TiO2
    -P25. The N-doped TiO2
    was compared with unmodified TiO2
    by carrying out the investigation
    on its properties using x-ray diffraction (XRD) analysis, Brunauer-Emmett-Teller (BET), Fourier transformed infrared
    spectroscopy (FTIR) and diffuse reflectance spectroscopy (UV-Vis DRS). The photocatalytic activities of N-doped TiO2
    and unmodified TiO2 were studied for photodegradation of reactive red 4 (RR4) under light emitting diode (LED) light
    irradiation. An active photoresponse under LED light irradiation was observed from N-doped TiO2
    with 60 min of time
    irradiation to complete RR4 color removal while no photocatalytic degradation was observed from unmodified.
    Matched MeSH terms: Urea
  3. Sensitivity enhancement of urea biosensor based on surface plasmon resonance and kretschmann configuration with graphene-mos2 hybrid structure
    Nur Akmar Jamil, Gan SM, Burhanuddin Yeop Majlis, Susthitha Menon P
    Sains Malaysiana, 2018;47:1033-1038.
    Artikel ini menganalisis biosensor resonans plasmon permukaan (SPR) dengan lapisan grafin yang meningkatkan
    kecekapan biosensor urea kerana penerapannya yang tinggi. Tatasusunan Kretschmann merupakan teknik yang paling
    berkesan digunakan untuk pengujaan plasmon. Dalam kajian ini, kami menganalisis kesan ekalapisan MoS2 dengan
    lapisan grafin yang didepositkan pada bahan plasmon, iaitu logam emas (Au), di dalam tatasusunan ini. Simulasi untuk
    menganalisis tatasusunan ini adalah berdasarkan kepada kaedah perbezaan terhingga domain masa (FDTD). Prestasi
    biosensor SPR dapat dipantau dengan menganalisis kepekaan dan lebar penuh pada separuh maksimum (FWHM) spektrum
    SPR. Pengukuran diperhatikan pada panjang gelombang 670 nm dan 785 nm untuk pengesanan urea. Indeks molar dan
    indeks biasan berbeza (RI) daripada 1.335 sehingga 1.342 untuk lapisan penderiaan. Keputusan menunjukkan peratus
    peningkatan kepekaan biosensor Au/MoS2
    /grafin berbanding biosensor Au konvensional adalah 98% dan 202% masingmasing
    pada panjang gelombang 670 nm dan 785 nm. Ini menunjukkan bahawa cadangan biosensor SPR yang novel ini
    adalah lebih sensitif untuk pengesanan urea.
    Matched MeSH terms: Urea
  4. Surface modification of cellulose nanomaterial for urea biosensor application
    Wan Elina Faradilla Wan Khalid, Lee YH, Mohamad Nasir Mat Arip
    Sains Malaysiana, 2018;47:941-949.
    Cellulose nanomaterial with rod-like structure and highly crystalline order, usually formed by elimination of the amorphous region from cellulose during acid hydrolysis. Cellulose nanomaterial with the property of biocompatibility and nontoxicity can be used for enzyme immobilization. In this work, urease enzyme was used as a model enzyme to study the surface modification of cellulose nanomaterial and its potential for biosensor application. The cellulose nanocrystal (CNC) surface was modified using 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation to introduce the carboxyl group at C6 primary alcohol. The success of enzyme immobilization and surface modification was confirmed using chemical tests and measured using UV-Visible spectrophotometer. The immobilization strategy was then applied for biosensor application for urea detection. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques were used for electroanalytical characterization of the urea biosensor.
    Matched MeSH terms: Urea; Urease
  5. Optimization of microencapsulation process for self-healing polymeric material
    Then S, Gan SN, Noor Hayaty Abu Kasim
    Sains Malaysiana, 2011;40:1179-1186.
    A series of poly(urea-formaldehyde) (PUF) microcapsules filled with dicyclopentadiene (DCPD) was successfully prepared by in situ polymerization. The effect of diverse process parameters and ingredients on the morphology of the microcapsules was observed by SEM, optical microscopy (OM) and digital microscopy. Different techniques for the characterization of the chemical structure and the core content were considered such as FT-IR and 1H-NMR as well as the characterization of thermal properties by DSC. High yields of free flowing powder of spherical microcapsules were produced. The synthesized microcapsules can be incorporated into another polymeric host material. In the event the host material cracks due to excessive stress or strong impact, the microcapsules would rupture to release the DCPD, which could polymerize to repair the crack.
    Matched MeSH terms: Urea
  6. Effects of different doses of fertilizers on growth and yield components of biodiesel plant (jatropha curcas l.)
    Inam Ali Shah, Sultan Mehmod Wazir, Rahmat Ali Khan
    Sains Malaysiana, 2017;46:117-122.
    Effects of different doses of fertilizers on growth and yield components of biodiesel plant (Jatropha curcas L.), was
    made in the prevailing environment of University of Science and Technology Bannu. The experiment was carried out in
    randomized complete block design (RCBD) with three replications. Nitrogen, phosphorus and potassium were applied
    in the form of urea, single super phosphate and potash in the shape of combined NPK, respectively, during sprouting
    of leaves and thereafter with each irrigation in split doses. The analysis of variance for number of branches per plant
    showed significant results indicated in ANOVA. Significantly the number of primary branches per plant 8.07 was recorded
    in T4 with the application of dose of (N P K: 2507.5 gm: 1091.5 gm: 501.5 gm). Maximum No. of secondary branches
    per plant (9.100) were recorded in T1 especially at both plots. Flower per inflorescence showed that maximum value
    (122.810) was recorded in T5 of especially at both plots. Inflorescence plant-1 showed that maximum value (39.477) were
    recorded in T1 and minimum value were noted as (12.733) at T3 on both the flats. The data for fruits per plant showed
    that maximum value (143.300) was recorded in T1. The seed index, which was the output of the aim of this research work,
    reflects highly significant differences in mean value observed for both subplots. Mean values showed that maximum seeds
    weight 45.86 was recorded in T1 of especially at both plots while low seed index was noted as 22.84 at T5 (N: 3400 gm,
    P: 1480 gm, K: 680 gm) at both the subplots.
    Matched MeSH terms: Urea
  7. Membran Selulosa Kenaf terjana semula daripada Larutan Akues NaOH/Urea yang digumpal menggunakan Asid Sulfurik
    Nor Aziawati Azahari, Sarani Zakaria, Hatika Kaco, Sin Yee Gan, Chia Chin Hua, Sharifah Nabihah Syed Jaafar, et al.
    Sains Malaysiana, 2017;46:795-801.
    Membran selulosa terjana semula (MS) daripada pulpa teras kenaf telah berjaya dihasilkan menggunakan kaedah pra penyejukan dan digumpal menggunakan larutan asid sulfurik. MS disediakan daripada pelarutan selulosa kenaf dalam larutan akues NaOH/urea dan larutan selulosa seterusnya digumpal dengan H2SO4 pada kepekatan 5-12 peratus berat (% bt.) selama 1-10 min. Pengaruh kepekatan penggumpal H2SO4 dan masa penggumpalan ke atas struktur, saiz liang, sifat mekanik dan ketelusan cahaya MS telah dikaji menggunakan pembelauan sinar-X (XRD), imbasan mikroskop elektron tekanan boleh ubah (VPSEM), penguji regangan dan spektrofotometer ultra-violet sinar tampak (UV-vis). Keputusan VPSEM menunjukkan perubahan saiz liang membran bergantung kepada kepekatan larutan penggumpal H2SO4, manakala masa penggumpalan tidak mempengaruhi saiz liang membran. Membran yang direndam dengan larutan penggumpal pada kepekatan 10 % bt. dan masa pembekuan yang sederhana iaitu 5 min menunjukkan sifat mekanik yang lebih baik dengan nilai kekuatan regangan masing-masing 41.9 dan 43.5 MPa. Oleh itu, kajian ini dapat memberikan maklumat mengenai penyediaan MS dengan pelbagai saiz liang dan sifat mekanik dengan pengubahsuaian kepekatan dan masa penggumpalan.
    Matched MeSH terms: Urea
  8. Effects of medicated and non-medicated multi-nutrient block supplementation on gastrointestinal parasite infestation and blood hematological parameters of lactating saanen goats
    Mira Panadi, Nor Dini Rusli, Khairiyah Mat, Wan Zahari Mohamed
    Sains Malaysiana, 2018;47:1447-1453.
    In a 90-day feeding trial, twenty four (24) Saanen lactating does were assigned to four treatment group. The treatments
    were feeding: basal diet only as a control (T1), basal diet with urea molasses multi-nutrient block (UMMB) (T2), basal
    diet with medicated urea molasses multi-nutrient block (MUMB) (T3) and basal diet with commercial mineral block (CMB)
    (T4). There were significant differences (p<0.05) between T2, T3 and T4 on the fecal egg count (FEC). Animals in T2
    and T3 showed moderate level of parasite infestation i.e. at 750 epg and 950 epg, respectively, while animals in T1 and
    T4 showed severe parasite load at 4917 epg and 1850 epg, respectively. There were no significant differences (p>0.05)
    between treatments on WBC, LYM, MON, GRA, RBC, HCT, MCV, MCH, PLT, MPV and PCT. However, significant effects (p<0.05)
    on HBG, MCHC, RDW and PDW were observed in T2 and T3. This research showed that UMMB and MUMB were effective
    in controlling parasite infestation in Saanen lactating dairy goats apart from improving their blood hematological
    parameters. Comparison with CMB showed that it is practical to be used for parasite control.
    Matched MeSH terms: Urea
  9. Evaluation of antihyperglycemic and antihyperlipidemic potential of Nelumbo Nucifera seeds in diabetic rats
    Khan SH, Ali F, Shah A, Kamran F, Jahan S
    Sains Malaysiana, 2016;45:1517-1523.
    The present study was aimed at evaluating antihyperglycemic and antihyperlipidemic activity of nuciferin and
    norcoclaurine constituents of N. nucifera seeds, a well-known medicinal plant. The alloxan (100 mg/kg b.w) induced
    diabetic rats (200-250 g) were divided into seven groups (n = 6). Group I; normal control, Group II; diabetic control,
    Group III; standard, Group lV-VII were fed with methanolic crude extracts (100, 200 mg/kg), nuciferin and norcoclaurine
    (10 mg/kg b.w.), received for 15 days in dose dependent manner. The study included different parameters; examination of
    oral glucose, fasting blood glucose, serum lipid profile and checking for body weight changes. In oral glucose examination,
    within 60 and 80 min of treatment, extracts, nuciferin and norcoclaurine significantly reduced blood glucose (p<0.05)
    and restored body weight in diabetic rats. Alloxan- induced diabetic rats showed 30-50% reduction of blood glucose
    level (p<0.05) and recovered 5-20% body weight at day 15 after ingestion of crude extracts (100-200 mg/kg b.w.); and
    nuciferin and norcoclaurine (each at 10 mg/kg b.w.). It also recovered significantly elevated biochemical parameters such
    as triglycerides (TG), low density lipoprotein (LDL), high density lipoprotein (HDL), total cholesterol (TC), serum urea and
    creatinine. Our findings indicated that N. nucifera seeds possess significant antihyperglycemic and antihyperlipidemic
    activity in diabetic rats.
    Matched MeSH terms: Urea
  10. Safety assessment of methanol extract of red dragon fruit (Hylocereus polyrhizus): acute and subchronic toxicity studies
    Hor SY, Ahmad M, Farsi E, Yam MF, Hashim MA, Lim CP, et al.
    Regul Toxicol Pharmacol, 2012 Jun;63(1):106-14.
    PMID: 22440551 DOI: 10.1016/j.yrtph.2012.03.006
    Recently, the fruits of Hylocereus polyrhizus, known as red dragon fruit, have received much attention from growers worldwide. However, there is little toxicological information regarding the safety of repeated exposure to these fruits. The present study evaluated the potential toxicity of a methanol extract of H. polyrhizus fruit after acute and subchronic administration in rats. In the acute toxicity study, single doses of fruit extract (1250, 2500 and 5000 mg/kg) were administered to rats by oral gavage, and the rats were then monitored for 14 days. In the subchronic toxicity study, the fruit extract was administered orally to rats at doses of 1250, 2500 and 5000 mg/kg/day for 28 days. There was no mortality or signs of acute or subchronic toxicity. There was no significant difference in body weight, relative organ weight or hematological parameters in the subchronic toxicity study. Biochemical analysis showed some significant changes, including creatinine, globulin, total protein and urea levels. No abnormality of internal organs was observed between treatment and control groups. The lethal oral dose of the fruit extract is more than 5000 mg/kg and the no-observed-adverse-effect level (NOAEL) of the extract for both male and female rats is considered to be 5000 mg/kg per day for 28 days.
    Matched MeSH terms: Urea/blood
  11. Stabilization of Human Serum Albumin against Urea Denaturation by Diazepam and Ketoprofen
    Manoharan P, Wong YH, Tayyab S
    Protein Pept Lett, 2015;22(7):611-7.
    PMID: 25961707
    Stabilizing effect of diazepam and ketoprofen, Sudlow's site II markers on human serum albumin (HSA) against urea denaturation was studied using fluorescence spectroscopy. The two-step, three-state urea transition of HSA was transformed into a single-step, two-state transition with the abolishment of the intermediate state along with a shift of the transition curve towards higher urea concentrations in the presence of diazepam or ketoprofen. Interestingly, a greater shift in the transition curve of HSA was observed in the presence of ketoprofen compared to diazepam. A comparison of the intrinsic fluorescence and three-dimensional fluorescence spectra of HSA and partially-denatured HSAs, obtained in the absence and the presence of diazepam or ketoprofen suggested significant retention of native-like conformation in the partially-denatured states of HSA in the presence of Sudlow's site II markers. Taken together, all these results suggested stabilization of HSA in the presence of diazepam or ketoprofen, being greater in the presence of ketoprofen.
    Matched MeSH terms: Urea/pharmacology*
  12. A Comparative Analysis of Protein Stabilizing Potential of Honey and Simulated Honey Sugar Cocktail
    Wong YH, Kadir HA, Tayyab S
    Protein Pept Lett, 2016;23(10):898-904.
    PMID: 27586182
    Urea and thermal denaturations of bovine serum albumin (BSA) were studied in the absence and the presence of honey or simulated honey sugar cocktail (SHSC) using far-UV CD and ANS fluorescence spectroscopy. Presence of 20% (w/v) honey or SHSC in the incubation mixture shifted the urea transition curve towards higher urea concentrations, being higher in the presence of honey and transformed the two-step, three-state transition into a single-step, two-state transition. A comparison of the far-UV CD and the ANS fluorescence spectra of 4.6 M urea-denatured BSA (U-BSA) in the absence and the presence of 20% (w/v) honey or SHSC suggested greater stabilizing potential of honey than SHSC, as U-BSA maintained native like conformation in the presence of 20% (w/v) honey. Furthermore, thermal transition curves of BSA were also shifted towards higher temperature range in the presence of 20% (w/v) SHSC and honey, showing greater shift in the presence of honey. The far-UV CD spectra of the heat-denatured BSA also showed greater stabilization in the presence of honey. Taken together all these results suggested greater protein stabilizing potential of honey than SHSC against chemical and thermal denaturations of BSA.
    Matched MeSH terms: Urea/chemistry
  13. Fulltext Microcapsules Filled with a Palm Oil-Based Alkyd as Healing Agent for Epoxy Matrix
    Shahabudin N, Yahya R, Gan SN
    Polymers (Basel), 2016 Apr 06;8(4).
    PMID: 30979216 DOI: 10.3390/polym8040125
    One of the approaches to prolong the service lifespan of polymeric material is the development of self-healing ability by means of embedded microcapsules containing a healing agent. In this work, poly(melamine-urea-formaldehyde) (PMUF) microcapsules containing a palm oil-based alkyd were produced by polymerization of melamine resin, urea and formaldehyde that encapsulated droplets of the suspended alkyd particles. A series of spherical and free-flowing microcapsules were obtained. The chemical properties of core and shell materials were characterized by Attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) and proton nuclear magnetic resonance spectroscopy (¹H-NMR). Differential scanning calorimetry (DSC) analysis showed a glass transition around -15 °C due to the alkyd, and a melting temperature at around 200 °C due to the shell. Thermogravimetric analysis (TGA) results showed that the core and shell thermally degraded within the temperature range of 200⁻600 °C. Field emission scanning electron microscope (FESEM) examination of the ruptured microcapsule showed smooth inner and rough outer surfaces of the shell. Flexural strength and microhardness (Vickers) of the cured epoxy compound were not affected with the incorporation of 1%⁻3% of the microcapsules. The viability of the healing reactions was demonstrated by blending small amounts of alkyd with epoxy and hardener at different ratios. The blends could readily cure to non-sticky hard solids at room temperature and the reactions could be verified by ATR-FTIR.
    Matched MeSH terms: Urea
  14. Fulltext A Study of Dielectric Properties of Proteinuria between 0.2 GHz and 50 GHz
    Mun PS, Ting HN, Ong TA, Wong CM, Ng KH, Chong YB
    PLoS One, 2015;10(6):e0130011.
    PMID: 26066351 DOI: 10.1371/journal.pone.0130011
    This paper investigates the dielectric properties of urine in normal subjects and subjects with chronic kidney disease (CKD) at microwave frequency of between 0.2 GHz and 50 GHz. The measurements were conducted using an open-ended coaxial probe at room temperature (25°C), at 30°C and at human body temperature (37°C). There were statistically significant differences in the dielectric properties of the CKD subjects compared to those of the normal subjects. Statistically significant differences in dielectric properties were observed across the temperatures for normal subjects and CKD subjects. Pearson correlation test showed the significant correlation between proteinuria and dielectric properties. The experimental data closely matched the single-pole Debye model. The relaxation dispersion and relaxation time increased with the proteinuria level, while decreasing with the temperature. As for static conductivity, it increased with proteinuria level and temperature.
    Matched MeSH terms: Urea/chemistry*
  15. Fulltext Urea and creatinine detection on nano-laminated gold thin film using Kretschmann-based surface plasmon resonance biosensor
    Menon PS, Said FA, Mei GS, Berhanuddin DD, Umar AA, Shaari S, et al.
    PLoS One, 2018;13(7):e0201228.
    PMID: 30052647 DOI: 10.1371/journal.pone.0201228
    This work investigates the surface plasmon resonance (SPR) response of 50-nm thick nano-laminated gold film using Kretschmann-based biosensing for detection of urea and creatinine in solution of various concentrations (non-enzymatic samples). Comparison was made with the presence of urease and creatininase enzymes in the urea and creatinine solutions (enzymatic samples), respectively. Angular interrogation technique was applied using optical wavelengths of 670 nm and 785 nm. The biosensor detects the presence of urea and creatinine at concentrations ranging from 50-800 mM for urea samples and 10-200 mM for creatinine samples. The purpose of studying the enzymatic sample was mainly to enhance the sensitivity of the sensor towards urea and creatinine in the samples. Upon exposure to 670 nm optical wavelength, the sensitivity of 1.4°/M was detected in non-enzymatic urea samples and 4°/M in non-enzymatic creatinine samples. On the other hand, sensor sensitivity as high as 16.2°/M in urea-urease samples and 10°/M in creatinine-creatininase samples was detected. The enhanced sensitivity possibly attributed to the increase in refractive index of analyte sensing layer due to urea-urease and creatinine-creatininase coupling activity. This work has successfully proved the design and demonstrated a proof-of-concept experiment using a low-cost and easy fabrication of Kretschmann based nano-laminated gold film SPR biosensor for detection of urea and creatinine using urease and creatininase enzymes.
    Matched MeSH terms: Urea/analysis*; Urease/analysis
  16. Fulltext Controlled Release Fertilizers: A Review on Coating Materials and Mechanism of Release
    Lawrencia D, Wong SK, Low DYS, Goh BH, Goh JK, Ruktanonchai UR, et al.
    Plants (Basel), 2021 Jan 26;10(2).
    PMID: 33530608 DOI: 10.3390/plants10020238
    Rising world population is expected to increase the demand for nitrogen fertilizers to improve crop yield and ensure food security. With existing challenges on low nutrient use efficiency (NUE) of urea and its environmental concerns, controlled release fertilizers (CRFs) have become a potential solution by formulating them to synchronize nutrient release according to the requirement of plants. However, the most significant challenge that persists is the "tailing" effect, which reduces the economic benefits in terms of maximum fertilizer utilization. High materials cost is also a significant obstacle restraining the widespread application of CRF in agriculture. The first part of this review covers issues related to the application of conventional fertilizer and CRFs in general. In the subsequent sections, different raw materials utilized to form CRFs, focusing on inorganic and organic materials and synthetic and natural polymers alongside their physical and chemical preparation methods, are compared. Important factors affecting rate of release, mechanism of release and mathematical modelling approaches to predict nutrient release are also discussed. This review aims to provide a better overview of the developments regarding CRFs in the past ten years, and trends are identified and analyzed to provide an insight for future works in the field of agriculture.
    Matched MeSH terms: Urea
  17. Conformational analysis of champedak galactose-binding lectin under different urea concentrations
    Kameel NI, Wong YH, Shuib AS, Tayyab S
    Plant Physiol Biochem, 2016 Jan;98:57-63.
    PMID: 26642433 DOI: 10.1016/j.plaphy.2015.11.007
    Conformational analysis of champedak galactose-binding (CGB) lectin under different urea concentrations was studied in phosphate-buffered saline (pH 7.2) using far-ultraviolet circular dichroism (far-UV CD), tryptophan (Trp) fluorescence and ANS fluorescence. In all cases, CGB lectin displayed a two-step, three-state transition. The first transition (from the native state to the intermediate state) started at ∼2.0 M urea and ended at ∼4.5 M urea, while the second transition (from the intermediate state to the completely denatured state) was characterized by the start- and end-points at ∼5.75 M and ∼7.5 M urea, respectively, when analyzed by the emission maximum of Trp fluorescence. A marked increase in the Trp fluorescence, ANS fluorescence and -CD values at 218 nm (-CD218 nm) represented the first transition, whereas a decrease in these parameters defined the second transition. On the other hand, emission maximum of the Trp fluorescence showed a continuous increase throughout the urea concentration range. Transformation of tetramer into monomer represented the first transition, whereas the second transition reflected the unfolding of monomer. Far-UV CD, Trp fluorescence and ANS fluorescence spectra were used to characterize the native, the intermediate and the completely denatured states of CGB lectin, obtained at 0.0 M, 5.0 M and 9.0 M urea, respectively. The intermediate state was characterized by the presence of higher secondary structures, increased ANS binding as well as increased Trp fluorescence intensity. A gradual decrease in the hemagglutination activity of CGB lectin was observed with increasing urea concentrations, showing complete loss at 4.0 M urea.
    Matched MeSH terms: Urea/pharmacology*
  18. Fenofibrate and dipyridamole treatments in low-doses either alone or in combination blunted the development of nephropathy in diabetic rats
    Balakumar P, Varatharajan R, Nyo YH, Renushia R, Raaginey D, Oh AN, et al.
    Pharmacol Res, 2014 Dec;90:36-47.
    PMID: 25263930 DOI: 10.1016/j.phrs.2014.08.008
    Low-doses of fenofibrate and dipyridamole have pleiotropic renoprotective actions in diabetic rats. This study investigated their combined effect relative to their individual treatments and lisinopril in rats with diabetic nephropathy. Streptozotocin (55mg/kg, i.p., once)-administered diabetic rats were allowed for 10 weeks to develop nephropathy. Diabetic rats after 10 weeks developed nephropathy with discernible renal structural and functional changes as assessed in terms of increase in kidney weight to body weight ratio (KW/BW), and elevations of serum creatinine, urea and uric acid, which accompanied with elevated serum triglycerides and decreased high-density lipoproteins. Hematoxylin-eosin, periodic acid Schiff and Masson trichrome staining confirmed renal pathological changes in diabetic rats that included glomerular capsular wall distortion, mesangial cell expansion, glomerular microvascular condensation, tubular damage and degeneration and fibrosis. Low-dose fenofibrate (30mg/kg, p.o., 4 weeks) and low-dose dipyridamole (20mg/kg, p.o., 4 weeks) treatment either alone or in combination considerably reduced renal structural and functional abnormalities in diabetic rats, but without affecting the elevated glucose level. Fenofibrate, but not dipyridamole, significantly prevented the lipid alteration and importantly the uric acid elevation in diabetic rats. Lisinopril (5mg/kg, p.o., 4 weeks, reference compound), prevented the hyperglycemia, lipid alteration and development of diabetic nephropathy. Lipid alteration and uric acid elevation, besides hyperglycemia, could play key roles in the development of nephropathy. Low-doses of fenofibrate and dipyridamole treatment either alone or in combination markedly prevented the diabetes-induced nephropathy. Their combination was as effective as to their individual treatment, but not superior in preventing the development of diabetic nephropathy.
    Matched MeSH terms: Urea/blood
  19. Chronotherapeutic effect of fisetin on expression of urea cycle enzymes and inflammatory markers in hyperammonaemic rats
    Subramanian P, Jayakumar M, Jayapalan JJ, Hashim OH
    Pharmacol Rep, 2014 Dec;66(6):1037-42.
    PMID: 25443732 DOI: 10.1016/j.pharep.2014.06.018
    BACKGROUND: Elevated blood ammonia leads to hyperammonaemia that affects vital central nervous system (CNS) functions. Fisetin, a naturally occurring flavonoid, exhibits therapeutic benefits, such as anti-cancer, anti-diabetic, anti-oxidant, anti-angiogenic, neuroprotective and neurotrophic effects.

    METHODS: In this study, the chronotherapeutic effect of fisetin on ammonium chloride (AC)-induced hyperammonaemic rats was investigated, to ascertain the time point at which the maximum drug effect is achieved. The anti-hyperammonaemic potential of fisetin (50mg/kg b.w. oral) was analysed when administered to AC treated (100mg/kg b.w. i.p.) rats at 06:00, 12:00, 18:00 and 00:00h. Amelioration of pathophysiological conditions by fisetin at different time points was measured by analysing the levels of expression of liver urea cycle enzymes (carbamoyl phosphate synthetase-I (CPS-I), ornithine transcarbamoylase (OTC) and argininosuccinate synthetase (ASS)), nuclear transcription factor kappaB (NF-κB p65), brain glutamine synthetase (GS) and inducible nitric oxide synthase (iNOS) by Western blot analysis.

    RESULTS: Fisetin increased the expression of CPS-I, OTC, ASS and GS and decreased iNOS and NF-κB p65 in hyperammonaemic rats. Fisetin administration at 00:00h showed more significant effects on the expression of liver and brain markers, compared with other time points.

    CONCLUSIONS: Fisetin could exhibit anti-hyperammonaemic effect owing to its anti-oxidant and cytoprotective influences. The temporal variation in the effect of fisetin could be due to the (i) chronopharmacological, chronopharmacokinetic properties of fisetin and (ii) modulations in the endogenous circadian rhythms of urea cycle enzymes, brain markers, redox enzymes and renal clearance during hyperammonaemia by fisetin. However, future studies in these lines are necessitated.

    Matched MeSH terms: Urea/metabolism*
  20. Impact of serum acetaminophen concentration on changes in serum potassium, creatinine and urea concentrations among patients with acetaminophen overdose
    Zyoud SH, Awang R, Sulaiman SA, Al-Jabi SW
    Pharmacoepidemiol Drug Saf, 2011 Feb;20(2):203-8.
    PMID: 21254292 DOI: 10.1002/pds.2060
    Acetaminophen overdose may be accompanied by electrolyte disturbances. The basis for electrolyte change appears to be due to increased fractional urinary electrolyte excretion.
    Matched MeSH terms: Urea/blood*
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