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Fulltext A Malaysian version of learning space preferences: a validation study

Sim JH, Foong CC, Pallath V, Hong WH, Vadivelu J

Int J Med Educ, 2021 May 27;12:86-93.
PMID: 34049286 DOI: 10.5116/ijme.6082.7c41

Objectives: This study aimed to validate a Malaysian version of a revised learning space questionnaire, as well as to test the utility of the revised questionnaire as a tool to investigate learning space preferences in a Malaysian medical school.
Methods: This is a cross-sectional survey. A convenient sample of 310 preclinical students of a public medical school in Malaysia were invited to participate. Validation data were collected using a revised 40-item, 5-point Likert scale learning space questionnaire. The questionnaires were administered online via a student e-learning platform. Data analysis was conducted using IBM SPSS version 24. Exploratory factor analysis was conducted to examine the factor structure of the revised questionnaire to provide evidence for construct validity. To assess the internal consistency of the revised questionnaire, Cronbach's alpha coefficients (α) were computed across all the items as well as for items within each of the factor.
Results: A total of 223 (71.94%) preclinical students completed and returned the questionnaire. In the final analysis, exploratory factor analysis with principal axis factoring and an oblimin rotation identified a six-factor, 20-item factor solution. Reliability analysis reported good internal consistency for the revised questionnaire, with an overall Cronbach's alpha of 0.845, and Cronbach's alpha ranging from 0.800 to 0.925 for the six factors.
Conclusions: This study established evidence for the construct validity and internal consistency of the revised questionnaire. The revised questionnaire appears to have utility as an instrument to investigate learning space preferences in Malaysian medical schools.
Fulltext A qualitative study on self-regulated learning among high performing medical students

Foong CC, Bashir Ghouse NL, Lye AJ, Khairul Anhar Holder NA, Pallath V, Hong WH, et al.

BMC Med Educ, 2021 Jun 05;21(1):320.
PMID: 34090439 DOI: 10.1186/s12909-021-02712-w

BACKGROUND: Self-regulated learning (SRL) is an important contributing element to the academic success of students. Literature suggests that the understanding of SRL among medical students is obscure as there is still some uncertainty about whether high performing medical students use SRL. This study explored the characteristics of high performing medical students from the SRL perspective to gain a better understanding of the application of SRL for effective learning.
METHODS: Twenty-one students who scored at the 90th percentile in written knowledge-based assessment consented to participate in this study. Each student wrote a guided reflective journal and subsequently attended a semi-structured interview. Students were prompted to explain the rationales for their answers. The data were then analysed using thematic analysis to identify patterns among these students from the SRL perspective. Two coders analysed the data independently and discussed the codes to reach a consensus.
RESULTS: High performing students set goals, made plans, and motivated themselves to achieve the goals. They put consistent efforts into their studies and applied effective learning strategies. They also employed coping mechanisms to deal with challenges. High performing students regularly evaluated their performance and adopted new strategies.
CONCLUSIONS: This study reported that high performing students applied SRL and described the rationales of practice. Medical schools could design SRL-driven interventions to enhance the learning experiences of medical students. Recommendations are made for students on how to apply SRL.
A review of natural polysaccharides for drug delivery applications: Special focus on cellulose, starch and glycogen

Gopinath V, Saravanan S, Al-Maleki AR, Ramesh M, Vadivelu J

Biomed Pharmacother, 2018 Nov;107:96-108.
PMID: 30086465 DOI: 10.1016/j.biopha.2018.07.136

Natural polysaccharides are renewable with a high degree of biocompatibility, biodegradability, and ability to mimic the natural extracellular matrix (ECM) microenvironment. Comprehensive investigations of polysaccharides are essential for our fundamental understanding of exploiting its potential as bio-composite, nano-conjugate and in pharmaceutical sectors. Polysaccharides are considered to be superior to other polymers, for its ease in tailoring, bio-compatibility, bio-activity, homogeneity and bio-adhesive properties. The main focus of this review is to spotlight the new advancements and challenges concerned with surface modification, binding domains, biological interaction with the conjugate including stability, polydispersity, and biodegradability. In this review, we have limited our survey to three essential polysaccharides including cellulose, starch, and glycogen that are sourced from plants, microbes, and animals respectively are reviewed. We also present the polysaccharides which have been extensively modified with the various types of conjugates for combating last-ditch pharmaceutical challenges.
A study on Candida biofilm growth characteristics and its susceptibility to aureobasidin A

Munusamy K, Vadivelu J, Tay ST

Rev Iberoam Micol, 2018 03 12;35(2):68-72.
PMID: 29544734 DOI: 10.1016/j.riam.2017.07.001

BACKGROUND: Biofilm is known to contribute to the antifungal resistance of Candida yeasts. Aureobasidin A (AbA), a cyclic depsipeptide targeting fungal sphingolipid biosynthesis, has been shown to be effective against several Candida species.
AIMS: The aim of this study was to investigate Candida biofilm growth morphology, its biomass, metabolic activity, and to determine the effects of AbA on the biofilm growth.
METHODS: The biofilm forming ability of several clinical isolates of different Candida species from our culture collection was determined using established methods (crystal violet and XTT assays). The determination of AbA planktonic and biofilm MICs was performed based on a micro-broth dilution method. The anti-biofilm effect of AbA on Candida albicans was examined using field emission scanning electron microscope (FESEM) analysis.
RESULTS: A total of 35 (29.7%) of 118 Candida isolates were regarded as biofilm producers in this study. Candida parapsilosis was the largest producer, followed by Candida tropicalis and C. albicans. Two morphological variants of biofilms were identified in our isolates, with 48.6% of the isolates showing mainly yeast and pseudohyphae-like structures, while the remaining ones were predominantly filamentous forms. The biofilm producers were divided into two populations (low and high), based on the ability in producing biomass and their metabolic activity. Candida isolates with filamentous growth, higher biomass and metabolic activity showed lower AbA MIC50 (at least fourfold), compared to those exhibiting yeast morphology, and lower biomass and metabolic activity. The observation of filament detachment and the almost complete removal of biofilm from AbA-treated C. albicans biofilm in FESEM analysis suggests an anti-biofilm effect of AbA.
CONCLUSIONS: The variability in the growth characteristics of Candida biofilm cultures affects susceptibility to AbA, with higher susceptibility noted in biofilm cultures exhibiting filamentous form and high biomass/metabolic activity.
Fulltext Acute respiratory failure in melioidosis

Puthucheary SD, Vadivelu J, Wong KT, Ong GS

Singapore Med J, 2001 Mar;42(3):117-21.
PMID: 11405563

In melioidosis caused by Burkholderia pseudomallei, although every organ in the body may be involved, the highest mortality of 73% occurs when the respiratory system is affected. These patients invariably die of acute respiratory failure. Most of them also have underlying predisposing factors like diabetes mellitus.
Adhesion and invasion attributes of Burkholderia pseudomallei are dependent on airway surface liquid and glucose concentrations in lung epithelial cells

Mariappan V, Thimma J, Vellasamy KM, Shankar EM, Vadivelu J

Environ Microbiol Rep, 2018 04;10(2):217-225.
PMID: 29393577 DOI: 10.1111/1758-2229.12624

Physiological constituents in airway surface liquids (ASL) appear to impact the adherence and invasion potentials of Burkholderia pseudomallei contributing to recrudescent melioidosis. Here, we investigated the factors present in ASL that is likely to influence bacterial adhesion and invasion leading to improved understanding of bacterial pathogenesis. Six B. pseudomallei clinical isolates from different origins were used to investigate the ability of the bacteria to adhere and invade A549 human lung epithelial cells using a system that mimics the physiological ASL with different pH, NaCl, KCl, CaCl2 and glucose concentrations. These parameters resulted in markedly differential adherence and invasion abilities of B. pseudomallei to the lung epithelial cells. The concentration of 20 mM glucose dramatically increased adherence and invasion by increasing the rate of pili formation in depiliated bacteria. Glucose significantly increased adherence and invasion of B. pseudomallei to A549 cells, and presence of NaCl, KCl and CaCl2 markedly ablated the effect despite the presence of glucose. Our data established a link between glucose, enhanced adhesion and invasion potentials of B. pseudomallei, hinting increased susceptibility of individuals with diabetes mellitus to clinical melioidosis.
Fulltext Altered Proteome of Burkholderia pseudomallei Colony Variants Induced by Exposure to Human Lung Epithelial Cells

Al-Maleki AR, Mariappan V, Vellasamy KM, Tay ST, Vadivelu J

PLoS One, 2015;10(5):e0127398.
PMID: 25996927 DOI: 10.1371/journal.pone.0127398

Burkholderia pseudomallei primary diagnostic cultures demonstrate colony morphology variation associated with expression of virulence and adaptation proteins. This study aims to examine the ability of B. pseudomallei colony variants (wild type [WT] and small colony variant [SCV]) to survive and replicate intracellularly in A549 cells and to identify the alterations in the protein expression of these variants, post-exposure to the A549 cells. Intracellular survival and cytotoxicity assays were performed followed by proteomics analysis using two-dimensional gel electrophoresis. B. pseudomallei SCV survive longer than the WT. During post-exposure, among 259 and 260 protein spots of SCV and WT, respectively, 19 were differentially expressed. Among SCV post-exposure up-regulated proteins, glyceraldehyde 3-phosphate dehydrogenase, fructose-bisphosphate aldolase (CbbA) and betaine aldehyde dehydrogenase were associated with adhesion and virulence. Among the down-regulated proteins, enolase (Eno) is implicated in adhesion and virulence. Additionally, post-exposure expression profiles of both variants were compared with pre-exposure. In WT pre- vs post-exposure, 36 proteins were differentially expressed. Of the up-regulated proteins, translocator protein, Eno, nucleoside diphosphate kinase (Ndk), ferritin Dps-family DNA binding protein and peptidyl-prolyl cis-trans isomerase B were implicated in invasion and virulence. In SCV pre- vs post-exposure, 27 proteins were differentially expressed. Among the up-regulated proteins, flagellin, Eno, CbbA, Ndk and phenylacetate-coenzyme A ligase have similarly been implicated in adhesion, invasion. Protein profiles differences post-exposure provide insights into association between morphotypic and phenotypic characteristics of colony variants, strengthening the role of B. pseudomallei morphotypes in pathogenesis of melioidosis.
Fulltext An Overview of Helicobacter pylori Survival Tactics in the Hostile Human Stomach Environment

Cheok YY, Lee CYQ, Cheong HC, Vadivelu J, Looi CY, Abdullah S, et al.

Microorganisms, 2021 Dec 03;9(12).
PMID: 34946105 DOI: 10.3390/microorganisms9122502

Helicobacter pylori is well established as a causative agent for gastritis, peptic ulcer, and gastric cancer. Armed with various inimitable virulence factors, this Gram-negative bacterium is one of few microorganisms that is capable of circumventing the harsh environment of the stomach. The unique spiral structure, flagella, and outer membrane proteins accelerate H. pylori movement within the viscous gastric mucosal layers while facilitating its attachment to the epithelial cells. Furthermore, secretion of urease from H. pylori eases the acidic pH within the stomach, thus creating a niche for bacteria survival and replication. Upon gaining a foothold in the gastric epithelial lining, bacterial protein CagA is injected into host cells through a type IV secretion system (T4SS), which together with VacA, damage the gastric epithelial cells. H. pylori does not only establishes colonization in the stomach, but also manipulates the host immune system to permit long-term persistence. Prolonged H. pylori infection causes chronic inflammation that precedes gastric cancer. The current review provides a brief outlook on H. pylori survival tactics, bacterial-host interaction and their importance in therapeutic intervention as well as vaccine development.
An immunohistochemical method for the diagnosis of melioidosis

Wong KT, Vadivelu J, Puthucheary SD, Tan KL

Pathology, 1996 May;28(2):188-91.
PMID: 8743829

In order to assess the usefulness of immunohistochemistry in the diagnosis of melioidosis, an infection by Burkholderia pseudomallei, polyclonal antibodies were applied to tissues from known cases of melioidosis and to other infected tissues. Formalin-fixed, paraffin-embedded tissues were stained by a modified immunoperoxidase technique. In autopsy tissues with inflammatory lesions of melioidosis, the cytoplasm of phagocytes and intact bacilli, both intra- and extracellular, were stained very strongly positive. Relatively more focal positive staining was observed in some but not all surgical biopsies from proven cases of melioidosis. In granulomas staining was mainly found in the central necrotic areas, with little staining of peripheral phagocytes. All control materials stained negative. Immunohistochemistry appears to be a useful diagnostic tool in melioidosis.
Analysis of core protein clusters identifies candidate variable sites conferring metronidazole resistance in Helicobacter pylori

Chua EG, Debowski AW, Webberley KM, Peters F, Lamichhane B, Loke MF, et al.

Gastroenterol Rep (Oxf), 2019 Feb;7(1):42-49.
PMID: 30792865 DOI: 10.1093/gastro/goy048

Background: Metronidazole is one of the first-line drugs of choice in the standard triple therapy used to eradicate Helicobacter pylori infection. Hence, the global emergence of metronidazole resistance in Hp poses a major challenge to health professionals. Inactivation of RdxA is known to be a major mechanism of conferring metronidazole resistance in H. pylori. However, metronidazole resistance can also arise in H. pylori strains expressing functional RdxA protein, suggesting that there are other mechanisms that may confer resistance to this drug.
Methods: We performed whole-genome sequencing on 121 H. pylori clinical strains, among which 73 were metronidazole-resistant. Sequence-alignment analysis of core protein clusters derived from clinical strains containing full-length RdxA was performed. Variable sites in each alignment were statistically compared between the resistant and susceptible groups to determine candidate genes along with their respective amino-acid changes that may account for the development of metronidazole resistance in H. pylori.
Results: Resistance due to RdxA truncation was identified in 34% of metronidazole-resistant strains. Analysis of core protein clusters derived from the remaining 48 metronidazole-resistant strains and 48 metronidazole-susceptible identified four variable sites significantly associated with metronidazole resistance. These sites included R16H/C in RdxA, D85N in the inner-membrane protein RclC (HP0565), V265I in a biotin carboxylase protein (HP0370) and A51V/T in a putative threonylcarbamoyl-AMP synthase (HP0918).
Conclusions: Our approach identified new potential mechanisms for metronidazole resistance in H. pylori that merit further investigation.
Analysis of integrons and associated gene cassettes of metallo-β-lactamase-positive Pseudomonas aeruginosa in Malaysia

Khosravi Y, Tay ST, Vadivelu J

J Med Microbiol, 2011 Jul;60(Pt 7):988-994.
PMID: 21436370 DOI: 10.1099/jmm.0.029868-0

In this study, 90 non-replicate imipenem-resistant Pseudomonas aeruginosa (IRPA) Malaysian isolates collected between October 2005 and March 2008 were subjected to a screening test for detection of the integron and the gene cassette. Class 1 integrons were detected in 54 IRPA clinical isolates, whilst three isolates contained class 2 integrons. Analysis of the gene cassettes associated with the class 1 integrons showed the detection of accC1 in isolates carrying bla(IMP-7) and aacA7 in isolates carrying bla(VIM-2). aadA6 was detected in two isolates carrying bla(IMP-4). Using random amplification of polymorphic DNA analysis, 14 PCR fingerprint patterns were generated from the 32 isolates carrying metallo-β-lactamase (MBL) genes (35.5 %), whilst 20 patterns were generated from the 58 non-MBL gene isolates (64.4 %). Based on the differences in the fingerprinting patterns, two clusters (A and B) were identified among the MBL-producing isolates. Cluster A comprised 18 isolates (56 %) carrying the bla(VIM) gene, whereas cluster B comprised 14 (44 %) isolates carrying the bla(IMP) gene. The non-MBL isolates were divided into clusters C and D. Cluster C comprised 22 non-MBL isolates harbouring class 1 integrons, whilst cluster D consisted of three isolates carrying class 2 integrons. These findings suggest that the class 1 integron is widespread among P. aeruginosa isolated in Malaysia and that characterization of cassette arrays of integrons will be a useful epidemiological tool to study the evolution of multidrug resistance and the dissemination of antibiotic resistance genes.
Anisotropic lanthanide-based nano-clusters for imaging applications

Yang X, Wang S, King TL, Kerr CJ, Blanchet C, Svergun D, et al.

Faraday Discuss, 2016 Jul 18.
PMID: 27430046

We have developed a new class of lanthanide nano-clusters that self-assemble using flexible Schiff base ligands. Cd-Ln and Ni-Ln clusters, [Ln8Cd24(L(1))12(OAc)39Cl7(OH)2] (Ln = Nd, Eu), [Eu8Cd24(L(1))12(OAc)44], [Ln8Cd24(L(2))12(OAc)44] (Ln = Nd, Yb, Sm) and [Nd2Ni4(L(3))2(acac)6(NO3)2(OH)2], were constructed using different types of flexible Schiff base ligands. These molecular nano-clusters exhibit anisotropic architectures that differ considerably depending upon the presence of Cd (nano-drum) or Ni (square-like nano-cluster). Structural characterization of the self-assembled particles has been undertaken using crystallography, transmission electron microscopy and small-angle X-ray scattering. Comparison of the metric dimensions of the nano-drums shows a consistency of size using these techniques, suggesting that these molecules may share similar structural features in both solid and solution states. Photophysical properties were studied by excitation of the ligand-centered absorption bands in the solid state and in solution, and using confocal microscopy of microspheres loaded with the compounds. The emissive properties of these compounds vary depending upon the combination of lanthanide and Cd or Ni present in these clusters. The results provide new insights into the construction of novel high-nuclearity nano-clusters and offer a promising foundation for the development of new functional nanomaterials.
Fulltext Anti-ulcerogenic activity of dentatin from clausena excavata Burm.f. against ethanol-induced gastric ulcer in rats: Possible role of mucus and anti-oxidant effect

Sidahmed HMA, Vadivelu J, Loke MF, Arbab IA, Abdul B, Sukari MA, et al.

Phytomedicine, 2019 Mar 01;55:31-39.
PMID: 30668441 DOI: 10.1016/j.phymed.2018.06.036

BACKGROUND: Clausena excavata Burm.f. (Rutaceae) has been used for the treatment of stomach disorders including peptic ulcer.
PURPOSE: In this study, we aimed to investigate dentatin isolated from C. excavata Burm.f., for anti-ulcer activity against ethanol ulcer model in rats.
METHODS: Gastric acid output, ulcer index, serum profile, histological evaluation using Hematoxylin and eosin (HE), periodic acid Schiff base stainings and immunohistochemical localization for heat shock proteins 70 (HSP70) were all investigated. Possible involvement of reduced glutathione (GSH), lipid peroxidation, prostaglandin E2 (PGE2), superoxide dismutase (SOD) enzymes, radical scavenging, and anti-Helicobacter pylori activity were investigated.
RESULTS: Dentatin showed anti-secretory activity against the pylorus ligature model and protected the gastric mucosa from ethanol ulceration, as revealed by the improved macroscopic and histological appearance. Dentatin significantly increased the gastric homogenate content of PGE2 GSH and SOD. Dentatin inhibited the lipid peroxidation as revealed by the reduced gastric content of malondialdehyde (MDA). Moreover, dentatin up-regulated HSP70 expression. However, dentatin showed insignificant anti-H. pylori activity.
CONCLUSION: Dentatin possesses gastro-protective activity, which could be attributed to the anti-secretory, mucus production, anti-oxidant, and HSP70 activities.
Antibacterial and antifungal properties of human cerumen

Lum CL, Jeyanthi S, Prepageran N, Vadivelu J, Raman R

J Laryngol Otol, 2009 Apr;123(4):375-8.
PMID: 18694532 DOI: 10.1017/S0022215108003307

To assess the antibacterial and antifungal properties of human cerumen by studying its effect on the growth of Staphylococcus aureus, Esherichia coli, Pseudomonas aeruginosa and Candida albicans.
Antibacterial biocompatible arginine functionalized mono-layer graphene: No more risk of silver toxicity

Rafieerad AR, Bushroa AR, Amiri A, Kalaiselvam K, Vellasamy KM, Vadivelu J

J Hazard Mater, 2018 10 15;360:132-140.
PMID: 30099356 DOI: 10.1016/j.jhazmat.2018.07.107

Antibacterial ability is vital in biological approaches as well as functional biomaterials. Besides, cytocompatibility aspect of biologic media, tissue and organs is always concern for appropriate synthesis. From the past, metallic/oxide phases of silver (Ag) material in various macro, micro or nano configurations have been widely used for antibacterial targets. While, background of Ag toxicity within particle, film and composites is posing gradual ion release affected by molecular bounding. Recent researches conducted to control, optimize and neutralize Ag limitations finding the benefits of ideal (∼ 100%) mediation against both Gram-negative and Gram-positive bacteria. Whereas, non-degradable releases history is still a challenge and its longer accumulation may cause to disrupt biostructures and disease risk. Thus, facile development of large-area organic materials with switchable bacteria toxicity and normal cell compatibility function is interesting for concerned approaches. Here, smart positively-charged stable arginine amino acid incorporated mono layer graphene (Arg-EMGr) nanobiocomposite introduced as useful antibacterial and safe bactericidal agent competitive with Ag direct. The immunity characteristic versus Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) comparably assessed with graphene oxide (GO) and different concentrations GO-AgNPs morphology. As cell viability matter, 1,3,5,7-days vitro culture assay shown attachment proliferation and cytotoxicity due to short interaction.
Anticancer effect of aromatic isoniazid derivatives in human gastric adenocarcinoma cells

Barathan M, Shivashekaregowda NKH, Hoong SM, Vellasamy KM, Vadivelu J

Toxicol Appl Pharmacol, 2023 Dec 15;481:116767.
PMID: 38007073 DOI: 10.1016/j.taap.2023.116767

Current treatments for stomach cancer are often effective in curing cancer. However, these treatments can also have significant side effects, and they may not be effective in all cases. Hence synthetic compounds exhibit promise as potential agents for cancer treatment. In a previous study, we identified (E)-N'- (2,3,4-trihydroxybenzylidene) isonicotinohydrazide (ITHB4) as a novel antimycobacterial derivative of isoniazid with cytotoxic effects on the MCF-7 breast cancer cell line. This led us to investigate the potential anti-cancer properties of ITHB4 against adenocarcinoma gastric (AGS) cell line. The cytotoxic effect of ITHB4 has been determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and further confirmed for anticancer properties by means of apoptosis, reactive oxygen species (ROS), nuclear fragmentation, lactate dehydrogenase (LDH), caspases, cytokines and morphological including phenotypic changes of cells assay. The ITHB4 demonstrated a lower IC50 in inhibiting growth of AGS cells at 24 h compared to 48 and 72 h. ITHB4 has also shown no toxicity human immune cells. Treatment of ITHB4 against AGS for 24 h eventually lead to formation of early apoptotic AGS cells, reduced mitochondrial membrane potential, nuclear condensation, and nuclear fragmentation lastly increased in ROS levels together with the release of LDH, and secretion of caspases. The altered cytokine profile in ITHB4 treated AGS hints at the possibility that ITHB4 may possess anti-tumor and anti-inflammatory properties. Our results in this study demonstrate that ITHB4 has almost similar chemotherapeutic properties against gastric adenocarcinoma cells compared to breast cancer cell. This is suggesting that the anticancer capabilities of this compound should be in vivo and clinically assessed.
Fulltext Antimicrobial susceptibility and genetic characterisation of Burkholderia pseudomallei isolated from Malaysian patients

Khosravi Y, Vellasamy KM, Mariappan V, Ng SL, Vadivelu J

ScientificWorldJournal, 2014;2014:132971.
PMID: 25379514 DOI: 10.1155/2014/132971

Burkholderia pseudomallei, the causative agent of melioidosis, is intrinsically resistant to many antibiotics. Ceftazidime (CAZ), the synthetic β-lactam, is normally used as the first-line antibiotic therapy for treatment of melioidosis. However, acquired CAZ resistance can develop in vivo during treatment with CAZ, leading to mortality if therapy is not switched to a different antibiotic(s) in a timely manner. In this study, susceptibilities of 81 B. pseudomallei isolates to nine different antimicrobial agents were determined using the disk diffusion method, broth microdilution test and Etest. Highest percentage of susceptibility was demonstrated to CAZ, amoxicillin/clavulanic acid, meropenem, imipenem, and trimethoprim/sulfamethoxazole. Although these drugs demonstrated the highest percentage of susceptibility in B. pseudomallei, the overall results underline the importance of the emergence of resistance in this organism. PCR results showed that, of the 81 B. pseudomallei, six multidrug resistant (MDR) isolates carried bpeB, amrB, and BPSS1119 and penA genes. Genotyping of the isolates using random amplified polymorphic DNA analysis showed six different PCR fingerprinting patterns generated from the six MDR isolates clusters (A) and eight PCR fingerprinting patterns generated for the remaining 75 non-MDR isolates clusters (B).
Fulltext Antisecretory, gastroprotective, antioxidant and anti-Helicobcter pylori activity of zerumbone from Zingiber zerumbet (L.) Smith

Sidahmed HM, Hashim NM, Abdulla MA, Ali HM, Mohan S, Abdelwahab SI, et al.

PLoS One, 2015;10(3):e0121060.
PMID: 25798602 DOI: 10.1371/journal.pone.0121060

BACKGROUND: Zingiber zerumbet Smith is a perennial herb, broadly distributed in many tropical areas. In Malaysia, it's locally known among the Malay people as "lempoyang" and its rhizomes, particularly, is widely used in traditional medicine for the treatment of peptic ulcer disease beyond other gastric disorders.
AIM OF THE STUDY: The aim of the current study is to evaluate the gastroprotective effect of zerumbone, the main bioactive compound of Zingiber zerumbet rhizome, against ethanol-induced gastric ulcer model in rats.
MATERIALS AND METHODS: Rats were pre-treated with zerumbone and subsequently exposed to acute gastric ulcer induced by absolute ethanol administration. Following treatment, gastric juice acidity, ulcer index, mucus content, histological analysis (HE and PAS), immunohistochemical localization for HSP-70, prostaglandin E2 synthesis (PGE2), non-protein sulfhydryl gastric content (NP-SH), reduced glutathione level (GSH), and malondialdehyde level (MDA) were evaluated in ethanol-induced ulcer in vivo. Ferric reducing antioxidant power assay (FRAP) and anti-H. pylori activity were investigated in vitro.
RESULTS: The results showed that the intragastric administration of zerumbone protected the gastric mucosa from the aggressive effect of ethanol-induced gastric ulcer, coincided with reduced submucosal edema and leukocyte infiltration. This observed gastroprotective effect of zerumbone was accompanied with a significant (p <0.05) effect of the compound to restore the lowered NP-SH and GSH levels, and to reduce the elevated MDA level into the gastric homogenate. Moreover, the compound induced HSP-70 up-regulation into the gastric tissue. Furthermore, zerumbone significantly (p <0.05) enhanced mucus production, showed intense PAS stain and maintained PG content near to the normal level. The compound exhibited antisecretory activity and an interesting minimum inhibitory concentration (MIC) against H. pylori strain.
CONCLUSION: The results of the present study revealed that zerumbone promotes ulcer protection, which might be attributed to the maintenance of mucus integrity, antioxidant activity, and HSP-70 induction. Zerumbone also exhibited antibacterial action against H. pylori.
Fulltext Assessment of Risk and Sero-Prevalence of Helicobacter pylori Colonization among Remote Orang Asli Tribes in Peninsula Malaysia

Thevakumar K, Chandren JR, Perez-Perez GI, Chua EG, Teh LK, Salleh MZ, et al.

PLoS One, 2016;11(7):e0159830.
PMID: 27441568 DOI: 10.1371/journal.pone.0159830

The epidemiology of Helicobacter pylori (H. pylori) infection is related to human poverty with marked differences between developing and developed countries. Socioeconomic factors and living standards are the main determinants of the age-dependent acquisition rate of H. pylori, and consequently its prevalence. The aim of this study was to assess the risk and sero-prevalence of H. pylori colonization among Orang Asli in Peninsula Malaysia. This cross-sectional study was conducted on Orang Asli subjects in seven isolated settlements spanning across all three major tribes (Negrito, Proto Malay and Senoi) in Malaysia. Socio-demographic characteristics of the subjects were obtained through interview. Subjects were tested for H. pylori colonization based on CagA and whole cell (WC) antigen serological assays. A total of 275 subjects participated in this study. Among these subjects, 115 (44.7%) were H. pylori sero-positive with highest sero-prevalence among Negrito (65.7%). Among subjects who were H. pylori sero-positive, CagA sero positivity was also significantly higher among Negrito. The highest proportion of respondents reported to be H. pylori sero-positive was from age group 30 years old and below (57.9%), males (56.2%), Negrito (48.6%) and live in bamboo house (92.3%). The highest proportion of respondents reported to be CagA sero-positive was from age group 30 years old and below (41.4%), males (35.6%) and Negrito (48.6%). The results of this study demonstrate that H. pylori colonization can be related to age, gender, tribes and house materials and CagA sero-positive stain closely associated with age, gender and tribes.
Fulltext Augmentation of Autoantibodies by Helicobacter pylori in Parkinson's Disease Patients May Be Linked to Greater Severity

Suwarnalata G, Tan AH, Isa H, Gudimella R, Anwar A, Loke MF, et al.

PLoS One, 2016;11(4):e0153725.
PMID: 27100827 DOI: 10.1371/journal.pone.0153725

Parkinson's disease (PD) is the second most common chronic and progressive neurodegenerative disorder. Its etiology remains elusive and at present only symptomatic treatments exists. Helicobacter pylori chronically colonizes the gastric mucosa of more than half of the global human population. Interestingly, H. pylori positivity has been found to be associated with greater of PD motor severity. In order to investigate the underlying cause of this association, the Sengenics Immunome protein array, which enables simultaneous screening for autoantibodies against 1636 human proteins, was used to screen the serum of 30 H. pylori-seropositive PD patients (case) and 30 age- and gender-matched H. pylori-seronegative PD patients (control) in this study. In total, 13 significant autoantibodies were identified and ranked, with 8 up-regulated and 5 down-regulated in the case group. Among autoantibodies found to be elevated in H. pylori-seropositive PD were included antibodies that recognize Nuclear factor I subtype A (NFIA), Platelet-derived growth factor B (PDGFB) and Eukaryotic translation initiation factor 4A3 (eIFA3). The presence of elevated autoantibodies against proteins essential for normal neurological functions suggest that immunomodulatory properties of H. pylori may explain the association between H. pylori positivity and greater PD motor severity.

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