Displaying publications 1 - 20 of 829 in total

  1. Lim CP, Md-Redzuan A, Lai YK, Borhanuddin B, Cheah FC
    Ann Acad Med Singap, 2017 10;46(10):395-398.
    PMID: 29177368
    Matched MeSH terms: Dose-Response Relationship, Drug*
  2. Doi SA
    Clin. Pharmacol. Ther., 1994 May;55(5):597-601.
    PMID: 8181204
    Pharmacokinetic-pharmacodynamic information regarding warfarin is used to produce a predictive model based on the idea that pharmacodynamic variability is more important than pharmacokinetic variability in the overall dose-response variability to warfarin. A modification of the maximum effect model is tested on a group of patients initiating oral anticoagulation with warfarin. Results indicate that the model can account for at least half of the total variation in maintenance doses observed (sample coefficient of determination, 0.53) and offer the physician a framework for dose requirements at the onset of therapy. The basic prediction equation is as follows: Maintenance dose = (11/international normalized ratio)-1, with a coefficient of correlation of 0.73 (95% confidence limits, 0.46-0.88). Application of this model may improve on the traditional empiric approach to warfarin dose adjustment.
    Matched MeSH terms: Dose-Response Relationship, Drug
  3. Tan GJ, Kwan TK
    Contraception, 1987 Sep;36(3):359-67.
    PMID: 3677679
    The effect of oxytocin on testicular function was examined in the adult male long-tailed macaques (Macaca fascicularis). The monkeys were either infused with increasing concentrations of synthetic oxytocin (16-128 m.i.u./min for 3 h) or injected daily for a week with the same hormone (20 i.u., i.v.) and the plasma testosterone levels measured. The results of the present study show that acute infusion or chronic injection of oxytocin does not significantly affect the plasma testosterone levels, suggesting that systemic control of testicular endocrine function by oxytocin may be unimportant.
    Matched MeSH terms: Dose-Response Relationship, Drug
  4. O'Holohan DR, Dondero TJ, Ponnampalam JT
    Med J Malaysia, 1973 Jun;27(4):310.
    PMID: 4270792
    Matched MeSH terms: Dose-Response Relationship, Drug
  5. Win TT, Aye SN, Lau Chui Fern J, Ong Fei C
    J Gastrointestin Liver Dis, 2020 Jun 03;29(2):191-198.
    PMID: 32530986 DOI: 10.15403/jgld-818
    BACKGROUND AND AIMS: The latest meta-analysis on the role of aspirin on various cancers was published in early 2018. By including the latest and updated primary observational studies, we aimed to conduct this systematic review and meta-analysis to synthesize stronger evidence on the role of aspirin in reducing gastric cancer (GC) risk.

    METHODS: The PubMed, Scopus, and MEDLINE databases were systematically searched up to December 2019 to identify relevant studies. Random-effects model was used to calculate summary ORs and 95%CI for I 2 >50%. If the heterogeneity is not significant, the fixed-effects model was used. Overall analysis of the studies, inverse variance weighting after transforming the estimates of each study into log OR and its standard error were used.

    RESULTS: 21 studies were included in this meta-analysis. Results showed that aspirin significantly reduced the GC risk (OR=0.64, 95%CI=0.54-0.76) with substantial heterogeneity (I 2 =96%). Effect of GC risk reduction in low dose (OR=0.80, 95%CI=0.59-1.09) is slightly greater than high dose aspirin (OR=1.08, 95%CI=0.77-1.52). Protective effect of aspirin uses >5 years (OR=0.67, 95%CI=0.34-1.31) was greater than <5 years (OR=1.01, 95%CI=0.72-1.43) Conclusion: In conclusion, this meta-analysis showed that low dose aspirin with longer duration of more than 5 years were associated with a statistically significant reduction in GC risk. However, due to possible confounding variables and bias, these results should be cautiously treated.

    Matched MeSH terms: Dose-Response Relationship, Drug
  6. Shindi O, Kanesan J, Kendall G, Ramanathan A
    Comput Methods Programs Biomed, 2020 Jun;189:105327.
    PMID: 31978808 DOI: 10.1016/j.cmpb.2020.105327
    BACKGROUND AND OBJECTIVES: In cancer therapy optimization, an optimal amount of drug is determined to not only reduce the tumor size but also to maintain the level of chemo toxicity in the patient's body. The increase in the number of objectives and constraints further burdens the optimization problem. The objective of the present work is to solve a Constrained Multi- Objective Optimization Problem (CMOOP) of the Cancer-Chemotherapy. This optimization results in optimal drug schedule through the minimization of the tumor size and the drug concentration by ensuring the patient's health level during dosing within an acceptable level.

    METHODS: This paper presents two hybrid methodologies that combines optimal control theory with multi-objective swarm and evolutionary algorithms and compares the performance of these methodologies with multi-objective swarm intelligence algorithms such as MOEAD, MODE, MOPSO and M-MOPSO. The hybrid and conventional methodologies are compared by addressing CMOOP.

    RESULTS: The minimized tumor and drug concentration results obtained by the hybrid methodologies demonstrate that they are not only superior to pure swarm intelligence or evolutionary algorithm methodologies but also consumes far less computational time. Further, Second Order Sufficient Condition (SSC) is also used to verify and validate the optimality condition of the constrained multi-objective problem.

    CONCLUSION: The proposed methodologies reduce chemo-medicine administration while maintaining effective tumor killing. This will be helpful for oncologist to discover and find the optimum dose schedule of the chemotherapy that reduces the tumor cells while maintaining the patients' health at a safe level.

    Matched MeSH terms: Dose-Response Relationship, Drug*
  7. Shuhaimi-Othman M, Nur-Amalina R, Nadzifah Y
    ScientificWorldJournal, 2012;2012:125785.
    PMID: 22666089 DOI: 10.1100/2012/125785
    Adult freshwater snails Melanoides tuberculata (Gastropod, Thiaridae) were exposed for a four-day period in laboratory conditions to a range of copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), nickel (Ni), iron (Fe), aluminium (Al), and manganese (Mn) concentrations. Mortality was assessed and median lethal times (LT₅₀) and concentrations (LC₅₀) were calculated. LT₅₀ and LC₅₀ increased with the decrease in mean exposure concentrations and times, respectively, for all metals. The LC(50) values for the 96-hour exposures to Cu, Cd, Zn, Pb, Ni, Fe, Al, and Mn were 0.14, 1.49, 3.90, 6.82, 8.46, 8.49, 68.23, and 45.59 mg L⁻¹, respectively. Cu was the most toxic metal to M. tuberculata, followed by Cd, Zn, Pb, Ni, Fe, Mn, and Al (Cu > Cd > Zn > Pb > Ni > Fe > Mn > Al). Metals bioconcentration in M. tuberculata increases with exposure to increasing concentrations and Cu has the highest accumulation (concentration factor) in the soft tissues. A comparison of LC₅₀ values for metals for this species with those for other freshwater gastropods reveals that M. tuberculata is equally sensitive to metals.
    Matched MeSH terms: Dose-Response Relationship, Drug
  8. Gill JS, Pillai SK, Koh OH, Jambunathan ST
    Acta Neurol Belg, 2011 Jun;111(2):155-6.
    PMID: 21748939
    Somnambulism or sleepwalking is a sleep disorder of arousal. Compared to in adults, pediatric and adolescent sleep disorders is still under-researched and poorly described. We report the successful use of low dose quietiapine, an atypical antipsychotic, in the treatment of a 15-year-old Indian male who presented with significant somnambulism. To the best of our knowledge, this is the first report on the use of quetiapine for the treatment of somnambulism in the literature. The presence of high voltage delta waves in sleepwalkers has been offered as a possible explanation for the patho-physiology of sleepwalking Quetiapine has been reported to decrease brain delta activity, and we postulate that this may be the mechanism on how it was beneficial for our patient.
    Matched MeSH terms: Dose-Response Relationship, Drug
  9. Zakaria ZA, Mohamad AS, Ahmad MS, Mokhtar AF, Israf DA, Lajis NH, et al.
    Biol Res Nurs, 2011 Oct;13(4):425-32.
    PMID: 21112917 DOI: 10.1177/1099800410386590
    Nonsteroidal anti-inflammatory drugs (NSAIDs) have been widely used for the treatment of inflammation. However, despite their effectiveness, most NSAIDs cause various side effects that negatively affect the management of inflammation and, in part, pain. Thus, there is a need to search for new anti-inflammatory agents with few, or no, side effects. Natural products of plant, animal, or microorganism origin have been good sources of new bioactive compounds. The present study was carried out to evaluate the acute and chronic anti-inflammatory activities of the essential oil of the rhizomes of Zingiber zerumbet (Zingiberaceae) using the carrageenan-induced paw edema and cotton pellet-induced granuloma tests, respectively. The effect of the essential oil on inflammatory- and noninflammatory-mediated pain was also assessed using the formalin test. Essential oil of Z. zerumbet, at doses of 30, 100, and 300 mg/kg, was administered intraperitoneally to rats. The substance exhibited significant anti-inflammatory activity both in acute and chronic animal models. The essential oil also inhibited inflammatory- and noninflammatory-mediated pain when assessed using the formalin test. In conclusion, the essential oil of Z. zerumbet possessed anti-inflammatory activity, in addition to its antinociceptive activity, which may explain its traditional uses to treat inflammatory-related ailments.
    Matched MeSH terms: Dose-Response Relationship, Drug
  10. Chuah TS, Loh JY, Hii YS
    Bull Environ Contam Toxicol, 2007 Nov;79(5):557-61.
    PMID: 17639329
    Acute and chronic effects of insecticide-endosulfan on the survival and reproduction performance of Moina macrocopa were determined in a laboratory study. Endosulfan concentrations that cause 50% mortality (LC50) after exposure for 24 and 48 h were 3.34 and 0.16 mg L(-1), respectively. Average longevity, initial age of reproduction and intrinsic rate of natural increase were reduced at 0.002 mg L(-1). Fecundity was greatly reduced by about 70% at 0.0004 mg L(-1) and approximately 97% at 0.002 mg L(-1) as compared to control organisms throughout the whole life span of 15 days. If environmental concentration of endosulfan do not exceed 0.0004 mg L(-1), application of this insecticide is unlikely to induce detrimental effects on these cladoceran populations in agro-ecosystem.
    Matched MeSH terms: Dose-Response Relationship, Drug
  11. De Silva AE, Kadir MA, Aziz MA, Kadzimin S
    ScientificWorldJournal, 2006 Feb 17;6:169-75.
    PMID: 16493521
    Differential effect of plant growth regulators and additives in proliferation of 18-month-old calli of Ananas comosus L. cv. Moris were assessed in vitro. The proliferation of callus relied on the growth regulators and additives. Of the different auxins supplemented in the Murashige and Skoog (MS) media, 32.22 microM alpha-naphthaleneacetic acid (NAA) gave the highest mean fresh weight of callus (46.817 g). Medium supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D) was inferior to NAA, while b-naphthoxy acetic acid (BNOA) and p-chlorophenoxy acetic acid (4-CPA) were not effective in proliferating 18-months old callus. Addition of casein hydrolysate and coconut water to NAA supplemented medium showed better proliferation and production of callus. However, in terms of callus production, NAA at 32.22 microM was economically better.
    Matched MeSH terms: Dose-Response Relationship, Drug
  12. Kirton LG
    Ann Trop Med Parasitol, 2005 Oct;99(7):695-714.
    PMID: 16212803
    Citridiol is an extract of the leaves of Corymbia citriodora (Myrtaceae), the lemon eucalyptus, and mostly consists of p-menthane-3,8-diol isomers. The effectiveness of this extract as a repellent against land leeches of the genus Haemadipsa (Haemadipsidae), primarily H. sylvestris, was tested in the laboratory and field, in Peninsular Malaysia. The formulation tested, Mosi-guard Natural spray, contained 40% (w/w) Citridiol in a base of ethanol, water and isopropanol. In the laboratory test, specimens of H. sylvestris that were placed within moist, untreated arenas enclosed by treated paper rings made numerous attempts to cross the rings but were prevented or delayed from crossing over, in a dose-dependent manner. Mortality was high among the leeches that attempted to cross over the paper rings that had been sprayed to saturation point but low among the leeches that attempted to cross over paper rings that had only been partially treated, with a droplet-spray. The field study was carried out using indices that were formulated to reflect the severity of leech attack and the degree of repellency. Heavy or moderate spraying of footwear and trouser legs (tucked into socks) not only gave complete protection against bites by H. sylvestris and H. picta but also provided high enough repellency to keep the treated footwear virtually free of leeches. Even a light spray greatly reduced the numbers of leeches on footwear and delayed their progression toward biting the test subjects, although it failed to prevent bites completely. There was no decline in the repellency of the Citridiol when hourly assessments were made over a 6-h test period in the field. The results of the study show that Citridiol is highly repellent as well as toxic to leeches, and can be effectively used to prevent leech bites in the field.
    Matched MeSH terms: Dose-Response Relationship, Drug
  13. Lee HL, Tien WD, Omar B
    PMID: 9322308
    The insecticide resistance status of 4 strains of adult male Blattella germanica, viz M (Malacca), E (England), F (restaurant) and K (cafeteria) against malathion and bendiocarb compared with a reference susceptible strain (S) was determined by using a modified WHO bioassay method. The results indicated that all the 4 strains were resistant to the insecticides albeit in different degrees. Resistance ratios for malathion ranged from 1.85-41.07-fold, whereas that of bendiocarb ranged from 1.68-4.83-fold. The biochemical microplate enzyme assays technique employed indicated that the resistance in M and E strains were attributed to acetylcholinesterase insensitivity. Multiple resistance was not detected in any of the 4 strains. Parameters of the identified resistance mechanism correlated well with the observed level of resistance. Agar gel electrophoresis showed that variations in esterase isoenzymes did not confer organophosphate and carbamate resistance to the 4 strains.
    Matched MeSH terms: Dose-Response Relationship, Drug
  14. Yap HH, Chong NL, Lee CY, Koay CA
    PMID: 9322312
    The residual efficacy of a relatively new pyrethroid, betacyfluthrin was compared with DDT against Anopheles sinensis Wiedemann in some village houses in Penang, Malaysia, for a period of 30 weeks. Efficacy was determined by exposing laboratory-cultured An. sinensis mosquitos to treated wall surfaces with either betacyfluthrin at 15 and 25 mg/m2 or DDT at 2,000 mg/m2 for one hour. Betacyfluthrin provided a longer residual effect (up to 210 days with > 70% mortality) compared with DDT. The potential of betacyfluthrin as a candidate for residual spraying for malaria control is discussed.
    Matched MeSH terms: Dose-Response Relationship, Drug
  15. Ismail R, Sarriff A, Abdul Rahman AF
    Med J Malaysia, 1990 Mar;45(1):57-64.
    PMID: 2152070
    We evaluated the usefulness of therapeutic drug monitoring (TDM) for gentamicin and the use of a two-point peak and trough pair concentration method to adjust its dose. Of the 194 patients included, initial concentrations were appropriate in only sixty nine. In the seventy one cases of dosage adjustments using this method, those attaining therapeutic levels increased overall from 38% to 67%. It is concluded that TDM for gentamicin with dosage adjustment using this simple pharmacokinetic approach is useful and adequate in monitoring for gentamicin therapy.
    Matched MeSH terms: Dose-Response Relationship, Drug
  16. Arisht SN, Abdul PM, Jasni J, Mohd Yasin NH, Lin SK, Wu SY, et al.
    Ecotoxicol Environ Saf, 2020 Oct 15;203:110991.
    PMID: 32888602 DOI: 10.1016/j.ecoenv.2020.110991
    The stimulant and toxicity effects of reported organic (acetic acid, propionic acid, butyric acid, formic acid, oil & grease) and inorganic (copper) by-products presented in palm oil mill effluent on anaerobic bacterial population were examined in this paper. The toxicity test had shown that acetic, propionic and butyric acids tend to stimulate the bacterial density level (survival rate more than 50%), while formic acid, copper, oil and grease were shown to have suppressed the density level (survival rate less than 50%). The highest biomass recorded was 1.66 mg/L for the concentration of acetic acid at 216 mg/L and lowest biomass concentration, 0.90 mg/L for copper at 1.40 mg/L. Biohydrogen-producing bacteria have a favourable growth rate around pH 5.5. The comparison of half maximal effective concentration (EC50) values between two test duration on the effects of organic and inorganic by-products postulate that bacteria had a higher tolerance towards volatile fatty acids. While acetic, butyric and propionic acids had exhibited higher tolerance EC50 values for bacteria, but the opposite trend was observed for formic acid, copper and oil & grease.
    Matched MeSH terms: Dose-Response Relationship, Drug
  17. Rahim J, Ahmad AH, Kassim NF, Ahmad H, Ishak IH, Rus AC, et al.
    J Am Mosq Control Assoc, 2016 Sep;32(3):210-216.
    PMID: 27802400
    Dengue vector control still heavily relies on the use of chemical insecticides, and the widespread use of insecticides has led to resistance in mosquitoes. The diagnostic dose is a key part of resistance monitoring. The present study corroborates the discriminating lethal doses of temephos and malathion based on dose-response of known susceptible strain of Aedes albopictus following the World Health Organization (WHO) diagnostic test procedure. Late 3rd and early 4th instars were tested with a range of larvicides to determine the lethal concentrations (LC50 and LC99) values. A slightly higher diagnostic dose of 0.020 mg/liter as compared with the WHO-established value of 0.012 mg/liter was observed for temephos. Meanwhile, a malathion diagnostic dose of 0.200 mg/liter is also reported here since there are no such reported values by WHO. Doubling the LC99 values of susceptible strains, 3 of the 5 wild-collected populations showed resistance to temephos and 2 showed incipient resistance; all 5 populations showed incipient resistance to malathion. The revised and established lethal diagnostic dose findings from the current work are crucial to elaborate on the variation in susceptibility of Ae. albopictus in future resistance monitoring programs in Malaysia.
    Matched MeSH terms: Dose-Response Relationship, Drug
  18. Premakumar CM, Turner MA, Morgan C
    Nutr Rev, 2019 12 01;77(12):878-889.
    PMID: 31504841 DOI: 10.1093/nutrit/nuz049
    CONTEXT: Very preterm neonates (VPNs) are unable to digest breast milk and therefore rely on parenteral nutrition (PN) formulations. This systematic review was prepared following PRISMA-P 2015 guidelines. For the purpose of this review, desirable mean plasma arginine concentration is defined as ≥80 micromoles/L.

    OBJECTIVE: The review was performed to answer the following research question: "In VPNs, are high amounts of arginine in PN, compared with low amounts of arginine, associated with appropriate circulating concentrations of arginine?" Therefore, the aims were to 1) quantify the relationship between parenteral arginine intakes and plasma arginine concentrations in PN-dependent VPNs; 2) identify any features of study design that affect this relationship; and 3) estimate the target parenteral arginine dose to achieve desirable preterm plasma arginine concentrations.

    DATA SOURCES: The PubMed, Scopus, Web of Science, and Cochrane databases were searched regardless of study design; review articles were not included.

    DATA EXTRACTION: Only articles that discussed amino acid (AA) intake and measured plasma AA profile post PN in VPNs were included. Data were obtained using a data extraction checklist that was devised for the purpose of this review.

    DATA ANALYSIS: Twelve articles met the inclusion criteria. The dose-concentration relationship of arginine content (%) and absolute arginine intake (mg/(kg × d)) with plasma arginine concentrations showed a significant positive correlation (P < 0.001).

    CONCLUSION: Future studies using AA solutions with arginine content of 17%-20% and protein intakes of 3.5-4.0 g/kg per day may be needed to achieve higher plasma arginine concentrations.

    Matched MeSH terms: Dose-Response Relationship, Drug
  19. Zaizuhana S, Puteri J Noor MB, Noral'ashikin Y, Muhammad H, Rohana AB, Zakiah I
    Trop Biomed, 2006 Dec;23(2):214-9.
    PMID: 17322824 MyJurnal
    Kacip Fatimah also known as Labisia pumila (Myrsinaceae), is a traditional herbal medicine with a long history in the Malay community. It has been used by many generations of Malay women to induce and facilitate childbirth as well as a post-partum medicine. We tested the genotoxic potential of Kacip Fatimah in bone marrow cells obtained from Sprague-Dawley rats using micronuclei formation as the toxicological endpoints. Five groups of five male rats each were administered orally for two consecutive days with doses of 100, 700 and 2000 mg/kg body weight of Kacip Fatimah extract dissolved in distilled water. Micronucleus preparation was obtained from bone marrow cells of the animals following standard protocols. No statistically significant increase in micronucleated polychromatic erythrocytes (MNPCEs) was observed at any dose level and sacrifice/harvest time point (24, 48 and 72h). However, a significant decrease in polychromatic erythrocytes/normochromatic erythrocytes (PCE:NCE) ratio was observed from the highest dose level (2000 mg/kg of body weight) at 48h harvest time point. In this study, we investigated the effect of Kacip Fatimah on mammalian bone marrow cells using micronuclei formation to assess the genotoxicity of the herb.
    Matched MeSH terms: Dose-Response Relationship, Drug
  20. Jahan N, Abd Manan F, Mansoor A, Zaidi MA, Shahwani MN, Javed MA
    ScientificWorldJournal, 2018;2018:8180174.
    PMID: 30356418 DOI: 10.1155/2018/8180174
    Rice production is decreasing by abiotic stresses like heavy metals. In such circumstances, producing food for growing human population is a challenge for plant breeders. Excess of Al3+ in soil has become threat for high yield of rice. Improvement of crop is one of potential solution for high production. The aim of this study was to develop the new method for optimization of Al3+ toxicity tolerance in indica rice at germination stag using two-way ANOVA and Duncan's multiple-range test (DMRT). Seeds of two indica rice cultivars (Pokkali and Pak Basmati) were exposed in different concentrations (control, 5 mM, 15 mM, and 20 mM) of Al3+ toxicity at pH 4 ±0.2 for two weeks. Germination traits such as final germination percentage (FG%), germination energy (GE), germination speed (GS), germination index (GI), mean time of germination (MGT), germination value (GV), germination velocity (GVe), peak value of germination (GPV), and germination capacity (GC) and growth traits such as root length (RL), shoot length (SL), total dry biomass (TDB), and germination vigour index (GVI) were measured. To obtain the maximum number of significance (≤ 0.01%) parameters in each concentration of Al3+ toxicity with control, two-way ANOVA was established and comparison of mean was done using DMRT. The results showed that 5 mM, 10 mM, and 15 mM have less significant effects on the above-mentioned parameters. However, 20 mM concentration of Al3+ produced significant effects (≤ 0.01%). Therefore, 20 mM of Al3+ is considered optimized limit for indica cultivars (Pokkali and Pak Basmati).
    Matched MeSH terms: Dose-Response Relationship, Drug
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