Displaying publications 41 - 60 of 160 in total

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  1. Chen LH, Sung TC, Lee HH, Higuchi A, Su HC, Lin KJ, et al.
    Biomater Sci, 2019 Aug 14.
    PMID: 31411209 DOI: 10.1039/c9bm00418a
    Recombinant vitronectin-grafted hydrogels were developed by adjusting surface charge of the hydrogels with grafting of poly-l-lysine for optimal culture of human embryonic stem cells (hESCs) under xeno- and feeder-free culture conditions, with elasticity regulated by crosslinking time (10-30 kPa), in contrast to conventional recombinant vitronectin coating dishes, which have a fixed stiff surface (3 GPa). hESCs proliferated on the hydrogels for over 10 passages and differentiated into the cells derived from three germ layers indicating the maintenance of pluripotency. hESCs on the hydrogels differentiated into cardiomyocytes under xeno-free culture conditions with much higher efficiency (80% of cTnT+ cells) than those on conventional recombinant vitronectin or Matrigel-coating dishes just only after 12 days of induction. It is important to have an optimal design of cell culture biomaterials where biological cues (recombinant vitronectin) and physical cues (optimal elasticity) are combined for high differentiation of hESCs into specific cell lineages, such as cardiomyocytes, under xeno-free and feeder-free culture conditions.
    Matched MeSH terms: Drug Combinations
  2. Sukonthasarn A, Chia YC, Wang JG, Nailes J, Buranakitjaroen P, Van Minh H, et al.
    J Clin Hypertens (Greenwich), 2021 03;23(3):545-555.
    PMID: 33086429 DOI: 10.1111/jch.14075
    Polypill is a fixed-dose combination of medications with proven benefits for the prevention of cardiovascular disease (CVD). Its role in CVD prevention has been extensively debated since the inception of this concept in 2003. There are two major kinds of polypills in clinical studies. The first is polypill that combines multiple low-dose medications for controlling only one CVD risk factor (such as high blood pressure or high serum cholesterol). These "single-purpose" polypills were mostly developed from original producers and have higher cost. The polypill that combines 3-4 pharmaceutical components, each with potential to reduce one major cardiovascular risk factors is "multi-purpose" or "cardiovascular" polypill. Using data from various clinical trials and from meta-analysis, Wald and Law claimed that this "cardiovascular" polypill when administered to every individual older than 55 years could reduce the incidence of CVD by more than 80%. Several short and intermediate to long-term studies with different cardiovascular polypills in phase II and III trials showed that they could provide better adherence, equivalent, or better risk factor control and quality of life among users as compared to usual care. One recently published randomized controlled clinical trial demonstrated the effectiveness and safety of a four-component polypill for both primary and secondary CVD prevention with acceptable number needed to treat (NNT) to prevent one major cardiovascular event. Considering the slow achievement of CVD prevention in many poor- and middle-income Asian countries and also the need to further improve compliance of antihypertensive and lipid lowering medications in many high-income Asian countries, the concept of "cardiovascular polypill" could be very useful. With further support from ongoing polypill cardiovascular outcome trials, polypill could be the foundation of the population-based strategies for CVD prevention.
    Matched MeSH terms: Drug Combinations
  3. Foo TY, Mohd Noor N, Yazid MB, Fauzi MH, Abdull Wahab SF, Ahmad MZ
    BMC Emerg Med, 2020 10 08;20(1):81.
    PMID: 33032544 DOI: 10.1186/s12873-020-00373-4
    OBJECTIVES: The aim of this review is to elucidate the efficacy and side effects of ketofol in comparison to other anaesthetic agents during procedural sedation and analgesia.

    METHOD: The Cochrane Central Register of Controlled Trials (1996 to Feb 2019) and MEDLINE (1966 to Feb 2019) were searched, including the related randomised control trials and reviewed articles to find unpublished trials or trials not obtained via electronic searches. Inclusion criteria for the studies included comparing recovery time, recording clinician satisfaction, and assessing the adverse effects of ketofol.

    RESULTS: Eleven trials consisting of a total of 1274 patients met our criteria and were included in this meta-analysis. Five trials compared ketofol with a single agent, while six trials compared ketofol with combined agents. While comparing between ketofol and a single agent (either ketamine or propofol), ketofol showed significant effect on recovery time (MD: -9.88, 95% CI: - 14.30 to - 5.46; P = 0.0003; I2 = 92%). However, no significant difference was observed while comparing ketofol with combined agents (RR: 0.75, 95% CI: - 6.24 to 7.74; P < 0.001; I2 = 98%). During single-agent comparison, ketofol showed no significant differences in terms of clinician satisfaction (RR: 2.86, 95% CI: 0.64 to 12.69; P = 0.001; I2 = 90%), airway obstruction (RR: 0.72, 95% CI: 0.35 to 11.48; P = 0.81; I2 = 0%), apnoea (RR: 0.9, 95% CI: 0.33 to 2.44; P = 0.88; I2 = 0%), desaturation (RR: 1.11, 95% CI: 0.64 to 1.94; P = 0.28; I2 = 21%), nausea (RR: 0.52, 95% CI: 0.91 to 1.41; P = 0.2; I2 = 38%), and vomiting (RR: 0.63, 95% CI: 0.25 to 1.61; P = 0.18; I2 = 42%). During comparison with combined agents, ketofol was more effective in reducing hypotension (RR: 4.2, 95% CI: 0.2 to 0.85; P = 0.76; I2 = 0%), but no differences were observed in terms of bradycardia (RR: 0.70, 95% CI: 0.14 to 03.63; P = 0.09; I2 = 53%), desaturation (RR: 1.9, 95% CI: 0.15 to 23.6; P = 0.11; I2 = 61%), and respiratory depression (RR: 1.98, 95% CI: 0.18 to 21.94; P = 0.12; I2 = 59%).

    CONCLUSION: There is low certainty of evidence that ketofol improves recovery time and moderate certainty of evidence that it reduces the frequency of hypotension. There was no significant difference in terms of other adverse effects when compared to other either single or combined agents.

    TRIAL REGISTRATION: PROSPERO CRD42019127278 .

    Matched MeSH terms: Drug Combinations
  4. Ahmad MN, Shuhaimen MS, Normaya E, Omar MN, Iqbal A, Ku Bulat KH
    J Texture Stud, 2020 10;51(5):810-829.
    PMID: 32401337 DOI: 10.1111/jtxs.12529
    Meat tenderness is one of the most important organoleptic properties in determining consumer acceptance in meat product marketability. Therefore, an effective meat tenderization method is sought after by exploring plant-derived proteolytic enzymes as meat tenderizer. In this study, a novel protease from Cashew was identified as a new alternative halal meat tenderizer. The extraction of cashew protease was optimized using response surface methodology (R2 = 0.9803) by varying pH, CaCl2 concentration, mixing time, and mass. pH 6.34, 7.92 mM CaCl2 concentration, 5.51 min mixing time, and 19.24 g sample mass were the optimal extraction conditions. There was no significant difference (n = 3; p 
    Matched MeSH terms: Drug Combinations
  5. Lin DS, Wang TD, Buranakitjaroen P, Chen CH, Cheng HM, Chia YC, et al.
    J Clin Hypertens (Greenwich), 2021 Mar;23(3):556-567.
    PMID: 33305531 DOI: 10.1111/jch.14120
    Hypertension is a worldwide epidemic that continues to grow, with a subset of patients responding poorly to current treatment available. This is especially relevant in Asia, which constitutes 61% of the global population. Hypertension in Asia is a unique entity that is often salt-sensitive, nocturnal, and systolic predominant. Sacubitril/valsartan is a first-in-class angiotensin receptor neprilysin inhibitor that was first used in heart failure with reduced ejection fraction. Sacubitril inhibits neprilysin, a metallopeptidase that degrades natriuretic peptides (NPs). NPs exert sympatholytic, diuretic, natriuretic, vasodilatory, and insulin-sensitizing effects mostly via cyclic guanosine monophosphate (cGMP)-mediated pathways. As an antihypertensive agent, sacubitril/valsartan has outperformed angiotensin II receptor type 1 blockers (ARBs), with additional reductions of office systolic blood pressures ranging between 5 and 7 mmHg, in multiple studies in Asia and around the globe. The drug was well tolerated even in the elderly or those with chronic kidney disease. Its mechanisms of actions are particularly attractive for treatment of hypertension in Asia. Sacubitril/valsartan offers a novel, dual class, single-molecule property that may be considered as first-line antihypertensive therapy. Further investigations are needed to validate its safety for long-term use and to explore other potentials such as in the management of insulin resistance and obesity, which often coexist with hypertension in Asia.
    Matched MeSH terms: Drug Combinations
  6. Lim VKE, Halijah MY
    Med J Malaysia, 2001 Sep;56(3):365-9.
    PMID: 11732084
    The in vitro activity of sulperazon (cefoperazone/sulbactam) was tested against 94 ceftazidime-resistant strains of bacteria isolated from mostly seriously ill patients in critical care units. Acinetobacter baumanii, Pseudomonas aeruginosa and Klebsiella pneumoniae made up 80% of the pathogens studied; 90% of the Klebsiella strains were producers of extended-spectrum beta-lactamases (ESBL). The MIC90 of sulperazon for Klebsiella was 12 mg/l (range 1.5-16 mg/l), indicating that this drug may be a useful alternative for the treatment of ceftazidime-resistant, ESBL-producing Klebsiella.
    Matched MeSH terms: Drug Combinations
  7. Lim VK, Cheong YM
    Malays J Pathol, 1995 Dec;17(2):73-6.
    PMID: 8935129
    Beta-lactamase production is one of the major mechanisms of resistance amongst bacteria especially the enteric bacilli. The purpose of this study is to assess the in-vitro activity of Sulperazon, a combination of cefoperazone and an irreversible beta-lactamase inhibitor, sulbactam, against the cefoperazone resistant isolates of aerobic gram-negative bacilli. A total of 92 such strains were tested. It was found that at a concentration of < or = 8 mg/l of sulbactam added to cefoperazone 82% of Klebsiella spp, 100% of E. coli, 100% of Enterobacter spp, 33% of Pseudomonas aeruginosa, 67% of Pseudomonas spp and 62% of Acinetobacter spp that were resistant to cefoperazone alone were susceptible to the combination. Hence it is concluded that the addition of sulbactam to cefoperazone does expand the spectrum of the in-vitro activity of cefoperazone.

    Study site: General Hospital Kuala Lumpur
    Matched MeSH terms: Drug Combinations
  8. Kuah KB
    Med J Malaysia, 1975 Mar;30(3):223-6.
    PMID: 1160683
    Matched MeSH terms: Drug Combinations
  9. Saini, D., Nadig, G., Saini, R.
    MyJurnal
    The main objective of a root end filling material is to provide an apical seal that prevents the movement of bacteria and the diffusion of bacterial products from the root canal system into periapical tissues. The aim of this study was to compare the microleakage of three root end filling materials Mineral trioxide aggregate (MTA), Glass ionomer cement (GIC) and Silver GIC (Miracle Mix) using dye penetration technique under stereomicroscope. Forty-five extracted human maxillary central incisors were instrumented and obturated with gutta percha using lateral compaction technique. Following this, the teeth were stored in saline. After one week, teeth were apically resected at an angle of 90ï° to the long axis of the root and root end cavities were prepared. The teeth were divided into three groups of fifteen specimens each and were filled with Group I -MTA, Group II - GIC and Group III - Miracle Mix. The samples were coated with varnish and after drying, they were immersed in 1% methylene blue dye for 72 hours. The teeth were then rinsed, sectioned longitudinally and observed under stereomicroscope. The depth of dye penetration was measured in millimeters. Microleakage was found to be significantly less in MTA (0.83 mm) when compared to GIC (1.32 mm) (p < 0.001) and with Miracle Mix (1.39 mm) (p < 0.001) No significant difference was found when microleakage in Miracle Mix was compared to that of GIC (p = 0.752). Thus we concluded that MTA is a better material as root end filling material to prevent microleakage, in comparison to GIC and Miracle Mix.
    Matched MeSH terms: Drug Combinations
  10. Delilkan AE
    Anaesth Intensive Care, 1974 May;2(2):171-4.
    PMID: 4447237
    Matched MeSH terms: Drug Combinations
  11. Gong NC, Chan KE, Singham KT, Chai KH
    Med J Malaysia, 1974 Mar;28(3):194-6.
    PMID: 4278358
    Matched MeSH terms: Drug Combinations
  12. Ang HH, Lee EL, Matsumoto K
    Hum Exp Toxicol, 2003 Aug;22(8):445-51.
    PMID: 12948085 DOI: 10.1191/0960327103ht382oa
    In Malaysia, the phase 3 registration for traditional medicines was implemented on 1 January 1992 under the Control of Drugs and Cosmetics Regulation 1984, emphasizing quality, efficacy and safety (including the detection of the presence of heavy metals) in all pharmaceutical dosage forms of traditional medicine preparations. Therefore, a total of 100 products in various pharmaceutical dosage forms of a herbal preparation, were analysed for lead content using atomic absorption spectrophotometer. Results showed that 8% (eight products) possessed 10.64-20.72 ppm of lead, and therefore, do not comply with the quality requirement for traditional medicines in Malaysia. One of these products, M-Tongkat Ali (exhibited 10.64 +/-0.37 ppm of lead), was in fact already registered with the DCA Malaysia. The rest, Sukarno Tongkat Ali, Eurycoma Madu, Super Pill Tongkat Ali, Force Pill Tongkat Ali, Tender Pill Tongkat Ali, Super Pill Tongkat Ali Plus and Great Pill Tongkat Ali Plus have not registered with the DCA Malaysia and exhibited 12.24-20.72 ppm of lead. Although this study showed that only 92% of the products complied with the quality requirement for traditional medicines in Malaysia, however, they cannot be assumed safe from lead contamination because of batch-to-batch inconsistency.
    Matched MeSH terms: Drug Combinations
  13. Amy Suzana Abu Bakar, Norhafiza Razali, Mohammad Daniel Shafiq Hassan, Renu Agarwal
    MyJurnal
    Glaucoma is an optic neuropathy characterised by optic nerve degeneration associated with
    visual field defects. It remains the world’s number one cause of irreversible blindness and
    patients usually present at late stage of the disease since it is generally asymptomatic until
    severe. The disease is subdivided into primary and secondary with primary open-angle
    glaucoma (POAG) being the most common type. At present, lowering the intraocular pressure
    (IOP) remains the only proven efficient approach in delaying the onset or preventing the
    progression of the disease. Medical treatment with topical antiglaucoma agents is the
    treatment of choice in open angle glaucoma. The use of antiglaucoma drugs aims to reduce
    IOP by enhancing aqueous humour (AH) outflow, reducing AH production, or both. The choice
    to use any available treatment option should be carefully considered in an attempt to maximise
    benefits and reducing the risk of developing adverse drug reactions. This review highlights the
    six classes of ocular hypotensive agents currently in use for POAG treatment including
    prostaglandin analogues; -adrenergic receptor blockers; -2 adrenergic receptor stimulants;
    carbonic anhydrase inhibitors; muscarinic receptor stimulants; rho kinase inhibitors with
    regards to their mechanism/s of action and potential adverse drug reactions, and
    antiglaucoma fixed drug combinations.
    Matched MeSH terms: Drug Combinations
  14. Rafiqul ISM, Mimi Sakinah AM, Zularisam AW
    Prep Biochem Biotechnol, 2021;51(10):1060-1070.
    PMID: 33724897 DOI: 10.1080/10826068.2021.1897840
    Enzymatic production of bioxylitol from lignocellulosic biomass (LCB) provides a promising alternative to both chemical and fermentative routes. This study aimed to assess the impacts of catalytic variables on bioxylitol production from wood sawdust using xylose reductase (XR) enzyme and to optimize the bioprocess. Enzyme-based xylitol production was carried out in batch cultivation under various experimental conditions to obtain maximum xylitol yield and productivity. The response surface methodology (RSM) was followed to fine-tune the most significant variables such as reaction time, temperature, and pH, which influence the synthesis of bioxylitol from sawdust hydrolysate and to optimize them. The optimum time, temperature, and pH became were 12.25 h, 35 °C, and 6.5, respectively, with initial xylose 18.8 g/L, NADPH 2.83 g/L, XR 0.027 U/mg, and agitation 100 rpm. The maximum xylitol production was attained at 16.28 g/L with a yield and productivity of 86.6% (w/w) and 1.33 g/L·h, respectively. Optimization of catalytic parameters using sequential strategies resulted in 1.55-fold improvement in overall xylitol production. This study explores a novel strategy for using sawdust hemicellulose in bioxylitol production by enzyme technology.
    Matched MeSH terms: Drug Combinations
  15. Taha NA, Al-Rawash MH, Imran ZA
    Int Endod J, 2022 May;55(5):416-429.
    PMID: 35152464 DOI: 10.1111/iej.13707
    AIM: The aim of the study was to compare the outcome of full pulpotomy using 2 calcium silicate-based materials compared with mineral trioxide aggregate (MTA) in symptomatic mature permanent teeth with carious pulp exposure.

    METHODOLOGY: This study was designed as a parallel, double blind, randomized controlled trial where symptomatic mature permanent teeth with carious pulp exposure meeting the inclusion criteria were randomly treated with full pulpotomy using one of 3 calcium silicate-based materials (ProRoot MTA, Biodentine and TotalFill). Full pulpotomy was performed, and haemostasis was achieved via a cotton pellet moistened with 2.5% NaOCl. A 3-mm layer of the calcium silicate-based material was randomly placed as the pulpotomy agent through a block randomization process followed by a resin-based composite restoration. Postoperative periapical radiograph was taken. Clinical and radiographic evaluation were completed after 6 months and 1 year. The patient and evaluator were blinded to the type of materials used. Pain levels were scored preoperatively and 7 days after treatment. Effect of potential prognosis factors including gender, age, diagnosis, bleeding time and type of caries were also analysed.

    RESULTS: One hundred and sixty-four teeth in 146 patients received full pulpotomy and were randomly assigned to either the tested or control material through block randomization technique (50 MTA, 50 Biodentine and 64 TotalFill). The age ranged from 10 to 70 years. The diagnosis was irreversible pulpitis in 112 teeth (72%) and reversible pulpitis in 28 teeth (28%). The majority of patients presented with severe pain, during the first week 96.9% reported complete relief of pain or mild pain. Four cases had immediate failure. At 6 months the overall success rate was 92.2%, over 1 year 156/164 teeth attended follow-up with 12 failures (2 restorative failures and 10 endodontic failures), the overall success of pulpotomy at 1 year was 92.3% (144/156); 91.8% in MTA, 93.3% in Biodentine and 91.9% in TotalFill with no significant difference amongst the groups and no side effects observed. No significant association was evident between outcome and the investigated variables.

    CONCLUSIONS: The 1-year success rate of full pulpotomy did not differ significantly between Biodentine pulpotomy, TotalFill pulpotomy, and MTA pulpotomy. The study was registered with clinical trials; registration number (NCT04345263).

    Matched MeSH terms: Drug Combinations
  16. Bakar NS, Zin NM, Basri DF
    Pak J Pharm Sci, 2012 Jul;25(3):633-8.
    PMID: 22713953
    This study evaluated in vitro activity of 9 flavonoids in combination with vancomycin or oxacillin against vancomycin-intermediate Staphylococcus aureus (VISA) ATCC 700699 by employing the checkerboard method to obtain Minimal inhibitory concentration (MIC) and fractional inhibitory concentration (FIC) index. Six flavonoids namely hesperitin, rutin, naringenin, flavones, naringin and 3, 7-dihyroxyflavone which exhibited notable inhibitory activity (MIC values < 3200 μg/ml) were further evaluated for combination assay with antibiotics. The combinations of vancomycin+flavone and oxacillin+flavone were found synergistic with the FIC index value 0.094 and 0.126, respectively. Other combinations showed an additive interaction (FIC index = 1.063) but no antagonistic reaction (FIC index > 4) were observed. In time kill studies, oxacillin-flavone combination at synergistic concentration demonstrated bactericidal effect at 24 h period with concentration-dependent manner on the VISA strain. Following 1 h exposure, the combination also produced persistent effect on the bacteria growth for 2.9 hrs at 1x sub-MIC and more than 24 h at 5x of sub-MIC and there was a significant difference between both concentrations (p<0.05). Vancomycin-flavone combination, however, showed no concentration-dependent effect and lower PAE values (1.159 h and 2.322 h at 1x and 5x sub-MIC, respectively) on the VISA strain. In conclusion, flavone markedly intensifies the susceptibility of oxacillin against VISA and the combination can be implicated for further interaction studies at molecular level.
    Matched MeSH terms: Drug Combinations
  17. Ibraheem ZO, Basir R, Aljobory AKh, Ibrahim OE, Alsumaidaee A, Yam MF
    Biomed Res Int, 2014;2014:823879.
    PMID: 25045706 DOI: 10.1155/2014/823879
    The current study evaluates the impact of high fructose feeding in rat model of gentamicin induced nephrotoxicity. Sprague-Dawley rats weighing 180-200 g were randomized into four groups; (C) received standard rodents chow with free access to ad libitum drinking water for 8 weeks and was considered as control, (F) received standard rodents chow with free access to drinking water supplemented with 20% (W/V) fructose for the same abovementioned period, (FG) was fed as group F and was given 80 mg/kg (body weight)/day gentamicin sulphate intraperitoneally during the last 20 days of the feeding period, and (G) was given gentamicin as above and fed as group C. Renal function was assessed at the end of the treatment period through measuring serum creatinine, uric acid and albumin, creatinine clearance, absolute and fractional excretion of both sodium and potassium, twenty-four-hour urinary excretion of albumin, and renal histology. For metabolic syndrome assessment, fasting plasma glucose and insulin were measured and oral glucose tolerance test was performed throughout the treatment period. Results showed that gentamicin enhances progression of fructose induced metabolic syndrome. On the other hand, fructose pretreatment before gentamicin injection produced a comparable degree of renal dysfunction to those which were given fructose-free water but the picture of nephrotoxicity was somewhat altered as it was characterized by higher extent of glomerular congestion and protein urea. Overall, more vigilance is required when nephrotoxic drugs are prescribed for patients with fructose induced metabolic syndrome.
    Matched MeSH terms: Drug Combinations
  18. Naing C, Mak JW, Aung K, Wong JY
    Trans R Soc Trop Med Hyg, 2013 Feb;107(2):65-73.
    PMID: 23222952 DOI: 10.1093/trstmh/trs019
    The present review aimed to synthesise available evidence on the efficacy of dihydroartemisinin-piperaquine (DP) in treating uncomplicated Plasmodium falciparum malaria in people living in malaria-endemic countries by performing a meta-analysis of relevant studies. We searched relevant studies in electronic data bases up to December 2011. Published results from randomised controlled trials (RCTs) comparing efficacy of DP with other artemisinin-based combination therapies (ACTs), or non-ACTs, or placebo were selected. The primary endpoint was 28-day and 42-day treatment failure. We identified 26 RCTs. Many of the studies included in the present review were of high quality. Overall, DP, artesunate-mefloquine (MAS3) and artemether-lumefentrine (AL) were equally effective for reducing the risk of recurrent parasitaemia. The PCR confirmed efficacy of DP (99.5%) and MAS3 (97.7%) at day 28 exceeded 90%; both are efficacious. Comparable efficacy was also found for DP (95.6%) and AL (94.3%). The present review has documented that DP is comparable to other currently used ACTs such as MAS3 and AL in treating uncomplicated falciparum malaria. The better safety profile of DP and once-daily dosage improves adherence and its fixed co-formulation ensures that both drugs are taken together. Our conclusion is that DP has the potential to become a first-line antimalarial drug.
    Matched MeSH terms: Drug Combinations
  19. Jaswir I, Che Man YB, Hassan TH
    Asia Pac J Clin Nutr, 2005;14(4):402-13.
    PMID: 16326648
    Antioxidants are important inhibitory compounds against the oxidative deterioration of food. This study investigated the effects of various phytochemical antioxidant systems [oleoresin rosemary (OR), oleoresin sage (OS) and citric acid (CA)] on the physico-chemical characteristics of refined, bleached and deodorized (RBD) palm olein during the frying of potato chips. The effects of various mixtures of the antioxidants on the oil was also studied in repeated deep frying. The response surface methodology was used to optimize the composition of mixed antioxidants used. A comparative study was carried out with synthetic antioxidants. Samples of the oil after frying were analyzed for different physical and chemical properties. OR and OS were found to be effective phytochemical antioxidants protecting RBD palm olein against oxidative deterioration during frying.
    Matched MeSH terms: Drug Combinations
  20. Sayyed AH, Wright DJ
    J Econ Entomol, 2004 Dec;97(6):2043-50.
    PMID: 15666763
    Bioassays (at generation 1, G1) using fipronil, spinosad, indoxacarb, and Bacillus thuringiensis toxins Cry1Ac and Cry1Ca with a newly collected field population of Plutella xylostella (L.) from farmers fields in the Cameron Highlands, Malaysia, indicated a resistance ratio of approximately 400-, 1,170-, 330-, 2,840-, and 1,410-fold, respectively, compared with a laboratory-susceptible population of P. xylostella (ROTH). At G3, the field-derived population was divided into two subpopulations, one was selected (G3 to G7) with fipronil (fip-SEL), whereas the second was left unselected (UNSEL). Bioassays at G8 found that selection with fipronil gave a resistance ratio of approximately 490 compared with UNSEL and approximately 770 compared with ROTH. The resistance ratio for fipronil, spinosad, indoxacarb, Cry1Ac, and Cry1Ca in the UNSEL population declined significantly by G8. Logit regression analysis of F1 reciprocal crosses between fip-SEL (at G8) and UNSEL indicated that resistance to fipronil in the fip-SEL population was inherited as an autosomal, incompletely recessive (D(LC) = 0.37) trait. At the highest dose of fipronil tested, resistance was completely recessive, whereas at the lowest dose it was incompletely recessive. A direct test of monogenic inheritance based on a backcross of F1 progeny with fip-SEL suggested that resistance to fipronil was controlled by a single locus. The fip-SEL population at G8 showed little change in its response to spinosad and indoxacarb compared with G1, whereas its susceptibility to Cry1Ac and Cry1Ca increased markedly over the selection period. This suggests that there may be some low level of cross-resistance between fipronil, spinosad, and indoxacarb.
    Matched MeSH terms: Drug Combinations
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