Research in Malaysia

Recent research output from Malaysia (via PubMed). Updated automatically.

Envelope proteome changes driven by RamA overproduction in Klebsiella pneumoniae that enhance acquired β-lactam resistance.

J Antimicrob Chemother. 2017 Oct 06;:

Authors: Jiménez-Castellanos JC, Wan Nur Ismah WAK, Takebayashi Y, Findlay J, Schneiders T, Heesom KJ, Avison MB

Abstract
Objectives: In Klebsiella pneumoniae, overproduction of RamA results in reduced envelope permeability and reduced antimicrobial susceptibility but clinically relevant resistance is rarely observed. Here we have tested whether RamA overproduction can enhance acquired β-lactam resistance mechanisms in K. pneumoniae and have defined the envelope protein abundance changes upon RamA overproduction during growth in low and high osmolarity media.
Methods: Envelope permeability was estimated using a fluorescent dye accumulation assay. β-Lactam susceptibility was measured using disc testing. Total envelope protein production was quantified using LC-MS/MS proteomics and transcript levels were quantified using real-time RT-PCR.
Results: RamA overproduction enhanced β-lactamase-mediated β-lactam resistance, in some cases dramatically, without altering β-lactamase production. It increased production of efflux pumps and decreased OmpK35 porin production, though micF overexpression showed that OmpK35 reduction has little impact on envelope permeability. A survey of K. pneumoniae bloodstream isolates revealed ramA hyperexpression in 3 of 4 carbapenemase producers, 1 of 21 CTX-M producers and 2 of 19 strains not carrying CTX-M or carbapenemases.
Conclusions: Whilst RamA is not a key mediator of antibiotic resistance in K. pneumoniae on its own, it is potentially important for enhancing the spectrum of acquired β-lactamase-mediated β-lactam resistance. LC-MS/MS proteomics analysis has revealed that this enhancement is achieved predominantly through activation of efflux pump production.

PMID: 29029194 [PubMed - as supplied by publisher]

Cockroach Oothecal Parasitoid, Evania appendigaster (Hymenoptera: Evaniidae) Exhibits Oviposition Preference Towards Oothecal Age Most Vulnerable to Host Cannibalism.

J Econ Entomol. 2017 Sep 27;:

Authors: Tee HS, Lee CY

Abstract
Many female parasitoid wasps optimize host selection to balance the benefits of high-quality hosts and the costs of predator- or hyperparasitoid-induced mortality risks to maximize their fitness. Cannibalism exists in many insect species and affects survival of parasitoid larvae developing in or on parasitized hosts. However, little is known about how parasitoid wasps resolve the fitness consequence of host cannibalism-induced mortality risk during host selection. We examined the effect of oothecal age on cannibalism in the American cockroach Periplaneta americana (L.) (Dictyoptera: Blattidae) and its effect on host age selection and fitness of its oothecal parasitoid Evania appendigaster (L.) (Hymenoptera: Evaniidae). P. americana differentially cannibalized 1-d-old (30‒60%) versus 10- to 40-d-old oothecae (<9%). However, parasitoid females did not avoid but still preferred to parasitize 1-d-old (45%) over 10- to 40-d-old oothecae (1.6‒20%). The parasitism rate was greater and the handling time was shorter on 1-d-old compared to older oothecae. For parasitoid progeny emerging from different-aged oothecae, regression analysis showed that development time increased and body size (measured as hind tibia length) and longevity decreased with oothecal age. These results demonstrate that reduced parasitoid progeny survival due to host cannibalism did not change the parasitoid's oviposition preference for newly laid oothecae, and that E. appendigaster females traded progeny survival for fitness gains for themselves and their progeny.

PMID: 29029091 [PubMed - as supplied by publisher]

A polyphenol-enriched diet and Ascaris suum infection modulate mucosal immune responses and gut microbiota composition in pigs.

PLoS One. 2017;12(10):e0186546

Authors: Williams AR, Krych L, Fauzan Ahmad H, Nejsum P, Skovgaard K, Nielsen DS, Thamsborg SM

Abstract
Polyphenols are a class of bioactive plant secondary metabolites that are thought to have beneficial effects on gut health, such as modulation of mucosal immune and inflammatory responses and regulation of parasite burdens. Here, we examined the interactions between a polyphenol-rich diet supplement and infection with the enteric nematode Ascaris suum in pigs. Pigs were fed either a basal diet or the same diet supplemented with grape pomace (GP), an industrial by-product rich in polyphenols such as oligomeric proanthocyanidins. Half of the animals in each group were then inoculated with A. suum for 14 days to assess parasite establishment, acquisition of local and systemic immune responses and effects on the gut microbiome. Despite in vitro anthelmintic activity of GP-extracts, numbers of parasite larvae in the intestine were not altered by GP-supplementation. However, the bioactive diet significantly increased numbers of eosinophils induced by A. suum infection in the duodenum, jejunum and ileum, and modulated gene expression in the jejunal mucosa of infected pigs. Both GP-supplementation and A. suum infection induced significant and apparently similar changes in the composition of the prokaryotic gut microbiota, and both also decreased concentrations of isobutyric and isovaleric acid (branched-chain short chain fatty acids) in the colon. Our results demonstrate that while a polyphenol-enriched diet in pigs may not directly influence A. suum establishment, it significantly modulates the subsequent host response to helminth infection. Our results suggest an influence of diet on immune function which may potentially be exploited to enhance immunity to helminths.

PMID: 29028844 [PubMed - in process]

Birth Cohort Consortium of Asia: Current and Future Perspectives.

Epidemiology. 2017 Oct;28 Suppl 1:S19-S34

Authors: Kishi R, Zhang JJ, Ha EH, Chen PC, Tian Y, Xia Y, Tsuchiya KJ, Nakai K, Kim S, Hong SJ, Hong YC, Lee JR, Jan Mohamed HJB, Parajuli RP, Adair LS, Chong YS, Guo YL, Wang SL, Nishijo M, Kido T, Tai PT, Nandasena S

Abstract
BACKGROUND: The environmental health of children is one of the great global health concerns. Exposures in utero and throughout development can have major consequences on later health. However, environmental risks or disease burdens vary from region to region. Birth cohort studies are ideal for investigating different environmental risks.
METHODS: The principal investigators of three birth cohorts in Asia including the Taiwan Birth Panel Study (TBPS), the Mothers and Children's Environmental Health Study (MOCEH), and the Hokkaido Study on Environment and Children' Health (Hokkaido Study) coestablished the Birth Cohort Consortium of Asia (BiCCA) in 2011. Through a series of five PI meetings, the enrolment criteria, aim of the consortium, and a first-phase inventory were confirmed.
RESULTS: To date, 23 birth cohorts have been established in 10 Asian countries, consisting of approximately 70,000 study subjects in the BiCCA. This article provides the study framework, environmental exposure and health outcome assessments, as well as maternal and infant characteristics of the participating cohorts.
CONCLUSIONS: The BiCCA provides a unique and reliable source of birth cohort information in Asian countries. Further scientific cooperation is ongoing to identify specific regional environmental threats and improve the health of children in Asia.

PMID: 29028672 [PubMed - in process]

Chemical constituents and medical benefits of Plantago major.

Biomed Pharmacother. 2017 Oct 10;96:348-360

Authors: Adom MB, Taher M, Mutalabisin MF, Amri MS, Abdul Kudos MB, Wan Sulaiman MWA, Sengupta P, Susanti D

Abstract
The medicinal benefits of Plantago major have been acknowledged around the world for hundreds of years. This plant contains a number of effective chemical constituents including flavonoids, alkaloids, terpenoids, phenolic acid derivatives, iridoid glycosides, fatty acids, polysaccharides and vitamins which contribute to its exerting specific therapeutic effects. Correspondingly, studies have found that Plantago major is effective as a wound healer, as well as an antiulcerative, antidiabetic, antidiarrhoeal, anti-inflammatory, antinociceptive, antibacterial, and antiviral agent. It also combats fatigue and cancer, is an antioxidant and a free radical scavenger. This paper provides a review of the medicinal benefits and chemical constituents of Plantago major published in journals from year 1937 to 2015 which are available from PubMed, ScienceDirect and Google Scholar.

PMID: 29028587 [PubMed - as supplied by publisher]

Size-Controlled and Optical Properties of Platinum Nanoparticles by Gamma Radiolytic Synthesis.

Appl Radiat Isot. 2017 Sep 09;130:211-217

Authors: Gharibshahi E, Saion E, Ashraf A, Gharibshahi L

Abstract
Gamma radiolytic synthesis was used to produce size-controlled spherical platinum nanoparticles from an aqueous solution containing platinum tetraammine and polyvinyl pyrrolidone. The structural characterizations were performed using X-ray diffraction, and transmission electron microscopy. The transmission electron microscopy was used to determine the average particle diameter, which decreased from 4.4nm at 80kGy to 2.8nm at 120kGy. The UV-visible absorption spectrum was measured and found that platinum nanoparticles exhibit two steady absorption maxima in UV regions due to plasmonic excitation of conduction electrons, which blue shifted to lower wavelengths with a decrease in particle size. We consider the conduction electrons of platinum nanoparticles to follow Thomas-Fermi-Dirac-Weizsacker atomic model that they are not entirely free but weakly bounded to particles at lower-energy states {n = 5, l = 2 or 5d} and {n = 6, l = 0 or 6s}, which upon receiving UV photon energy the electrons make intra-band quantum excitations to higher-energy states allowed by the principles of quantum number that results the absorption maxima. We found an excellent agreement between the experimental and theoretical results, which suggest that the optical absorption of metal nanoparticles could be fundamentally described by a quantum mechanical interpretation, which could be more relevant to photo-catalysis and heterogeneous catalysis.

PMID: 29028581 [PubMed - as supplied by publisher]

Prevalence of avian influenza (H9N2) in commercial quail, partridge, and turkey farms in Iran, 2014-2015.

Trop Anim Health Prod. 2017 Oct 13;:

Authors: Mehrabadi MHF, Bahonar A, Mirzaei K, Molouki A, Ghalyanchilangeroudi A, Ghafouri SA, Tehrani F, Lim SHE

Abstract
Avian influenza virus (AIV) H9N2 subtype is endemic in Iran and causes substantial economic loss to the growing poultry industry within the country. In this study, a cross-sectional analysis was carried out to determine the sero-prevalence of H9N2 in several commercial farms between the years 2014 and 2015. The comparison of the mean of serum titers and the ratio of sero-positive birds between all units were analyzed using one-way ANOVA test. In 2014, a total of 77 farms (58 turkey farms, 14 quail farms, and 5 partridge farms) and 894 birds (682 turkeys, 154 quails, and 58 partridges) were sampled while in 2015, a total of 69 farms (54 turkey farms, 8 quail farms, and 7 partridge farms) and 856 birds (675 turkeys, 105 quails, and 76 partridges) were sampled. Of that, 52 of 77 sampled farms (67.5%) and 437 of 894 samples (48.9%) were positive for H9N2 in 2014 while. Forty-one of 69 farms (59.4%) and 307 of 856 sera (35.9%) were positive in 2015. Furthermore, the mean titer of partridge farms was significantly lower than that of turkey farms (p < 0.01) and the mean percentage of sero-positive turkey farms was significantly higher than partridge farms (p < 0.01) in 2014. In 2015, no significant difference was observed between the mean sera titer amongst farms and percentage of sero-positive birds (p > 0.05). Our results indicated that H9N2 is circulating in these farms. Since many more such farms are being established for operations, in addition to the threat of emergence and continuous reemergence of the disease in these farms, enhanced veterinary biosecurity measures on farms are required for mitigation.

PMID: 29027604 [PubMed - as supplied by publisher]

Related Articles

Cost effectiveness analysis of carbetocin during cesarean section in a high volume maternity unit.

J Obstet Gynaecol Res. 2017 Oct 13;:

Authors: Voon HY, Shafie AA, Bujang MA, Suharjono HN

Abstract
AIM: To evaluate the cost effectiveness of carbetocin compared to oxytocin when used as prophylaxis against post-partum hemorrhage (PPH) during cesarean deliveries.
METHODS: A systematic review of the literature was performed to identify randomized controlled trials that compared the use of carbetocin to oxytocin in the context of cesarean deliveries. Cost effectiveness analysis was then performed using secondary data from the perspective of a maternity unit within the Malaysian Ministry of Health, over a 24 h time period.
RESULTS: Seven randomized controlled trials with over 2000 patients comparing carbetocin with oxytocin during cesarean section were identified. The use of carbetocin in our center, which has an average of 3000 cesarean deliveries annually, would have prevented 108 episodes of PPH, 104 episodes of transfusion and reduced the need for additional uterotonics in 455 patients. The incremental cost effectiveness ratio of carbetocin for averting an episode of PPH was US$278.70.
CONCLUSION: Reduction in retreatment, staffing requirements, transfusion and potential medication errors mitigates the higher index cost of carbetocin. From a pharmacoeconomic perspective, in the context of cesarean section, carbetocin was cost effective as prophylaxis against PPH. Ultimately, the relative value placed on the outcomes above and the individual unit's resources would influence the choice of uterotonic.

PMID: 29027315 [PubMed - as supplied by publisher]

Related Articles

Ursodeoxycholic acid protects cardiomyocytes against cobalt chloride induced hypoxia by regulating transcriptional mediator of cells stress hypoxia inducible factor 1α and p53 protein.

Cell Biochem Funct. 2017 Oct 12;:

Authors: Mohamed AS, Hanafi NI, Sheikh Abdul Kadir SH, Md Noor J, Abdul Hamid Hasani N, Ab Rahim S, Siran R

Abstract
In hepatocytes, ursodeoxycholic acid (UDCA) activates cell signalling pathways such as p53, intracellular calcium ([Ca(2+) ]i ), and sphingosine-1-phosphate (S1P)-receptor via Gαi -coupled-receptor. Recently, UDCA has been shown to protect the heart against hypoxia-reoxygenation injury. However, it is not clear whether UDCA cardioprotection against hypoxia acts through a transcriptional mediator of cells stress, HIF-1α and p53. Therefore, in here, we aimed to investigate whether UDCA could protect cardiomyocytes (CMs) against hypoxia by regulating expression of HIF-1α, p53, [Ca(2+) ]i , and S1P-Gαi -coupled-receptor. Cardiomyocytes were isolated from newborn rats (0-2 days), and hypoxia was induced by using cobalt chloride (CoCl2 ). Cardiomyocytes were treated with UDCA and cotreated with either FTY720 (S1P-receptor agonist) or pertussis toxin (PTX; Gαi inhibitor). Cells were subjected for proliferation assay, beating frequency, QuantiGene Plex assay, western blot, immunofluorescence, and calcium imaging. Our findings showed that UDCA counteracted the effects of CoCl2 on cell viability, beating frequency, HIF-1α, and p53 protein expression. We found that these cardioprotection effects of UDCA were similar to FTY720, S1P agonist. Furthermore, we observed that UDCA protects CMs against CoCl2 -induced [Ca(2+) ]i dynamic alteration. Pharmacological inhibition of the Gαi -sensitive receptor did not abolish the cardioprotection of UDCA against CoCl2 detrimental effects, except for cell viability and [Ca(2+) ]i . Pertussis toxin is partially effective in inhibiting UDCA protection against CoCl2 effects on CM cell viability. Interestingly, PTX fully inhibits UDCA cardioprotection on CoCl2 -induced [Ca(2+) ]i dynamic changes. We conclude that UDCA cardioprotection against CoCl2 -induced hypoxia is similar to FTY720, and its actions are not fully mediated by the Gαi -coupled protein sensitive pathways. Ursodeoxycholic acid is the most hydrophilic bile acid and is currently used to treat liver diseases. Recently, UDCA is shown to have a cardioprotection effects; however, the mechanism of UDCA cardioprotection is still poorly understood. The current data generated were the first to show that UDCA is able to inhibit the activation of HIF-1α and p53 protein during CoCl2 -induced hypoxia in cardiomyocytes. This study provides an insight of UDCA mechanism in protecting cardiomyocytes against hypoxia.

PMID: 29027248 [PubMed - as supplied by publisher]

Related Articles

Epac-induced ryanodine receptor type 2 activation inhibits sodium currents in atrial and ventricular murine cardiomyocytes.

Clin Exp Pharmacol Physiol. 2017 Oct 12;:

Authors: Valli H, Ahmad S, Sriharan S, Dean LD, Grace AA, Jeevaratnam K, Matthews HR, Huang CL

Abstract
Acute RyR2 activation by exchange protein directly activated by cAMP (Epac) reversibly perturbs myocyte Ca(2+) homeostasis, slows myocardial action potential conduction, and exerts pro-arrhythmic effects. Loose patch-clamp studies, preserving in vivo extracellular and intracellular conditions, investigated Na(+) current in intact cardiomyocytes in murine atrial and ventricular preparations following Epac activation. Depolarising steps to varying test voltages activated typical voltage-dependent Na(+) currents. Plots of peak current against depolarisation from resting potential gave pretreatment maximum atrial and ventricular currents of -20.23±1.48(17) and -29.8±2.4(10) pA/μm(2) (means± SEM (n)). Challenge by 8-CPT (1 μM) reduced these currents to -11.21±0.91(12) (p<0.004) and -19.3±1.6(11) pA/μm(2) (p<0.04) respectively. Currents following further addition of the RyR2 inhibitor dantrolene (10 μM) (-19.91±2.84(13) and -26.6±1.7(17)), and dantrolene whether alone (-19.53±1.97(8) and -27.6±1.9(14)) or combined with 8-CPT (-19.93±2.59(12) and -29.9±2.5(11)), were indistinguishable from pretreatment values (all p>>0.05). Assessment of the inactivation that followed by applying subsequent steps to a fixed voltage 100 mV positive to resting potential gave concordant results. Half-maximal inactivation voltages and steepness factors, and time constants for Na(+) current recovery from inactivation in double-pulse experiments, were similar through all the pharmacological conditions. Intracellular sharp microelectrode membrane potential recordings in intact Langendorff-perfused preparations demonstrated concordant variations in maximum rates of atrial and ventricular action potential upstroke, (dV/dt)max . We thus demonstrate an acute, reversible, Na(+) channel inhibition offering a possible mechanism for previously reported pro-arrhythmic slowing of AP propagation following modifications of Ca(2+) homeostasis, complementing earlier findings from chronic alterations in Ca(2+) homeostasis in genetically modified RyR2-P2328S hearts. This article is protected by copyright. All rights reserved.

PMID: 29027245 [PubMed - as supplied by publisher]

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