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Fulltext Validation of SYBR green I based closed-tube loop-mediated isothermal amplification (LAMP) assay for diagnosis of knowlesi malaria

Lai MY, Ooi CH, Lau YL

Malar J, 2021 Mar 25;20(1):166.
PMID: 33766038 DOI: 10.1186/s12936-021-03707-0

BACKGROUND: As an alternative to PCR methods, LAMP is increasingly being used in the field of molecular diagnostics. Under isothermal conditions at 65 °C, the entire procedure takes approximately 30 min to complete. In this study, we establish a sensitive and visualized LAMP method in a closed-tube system for the detection of Plasmodium knowlesi.
METHODS: A total of 71 malaria microscopy positive blood samples collected in blood spots were obtained from the Sarawak State Health Department. Using 18s rRNA as the target gene, nested PCR and SYBR green I LAMP assay were performed following the DNA extraction. The colour changes of LAMP end products were observed by naked eyes.
RESULTS: LAMP assay demonstrated a detection limit of 10 copies/µL in comparison with 100 copies/µL nested PCR. Of 71 P. knowlesi blood samples collected, LAMP detected 69 microscopy-positive samples. LAMP exhibited higher sensitivity than nested PCR assay. The SYBR green I LAMP assay was 97.1% sensitive (95% CI 90.2-99.7%) and 100% specific (95% CI 83.2-100%). Without opening the cap, incorporation of SYBR green I into the inner cap of the tube enabled the direct visualization of results upon completion of amplification. The positives instantaneously turned green while the negatives remained orange.
CONCLUSIONS: These results indicate that SYBR green I LAMP assay is a convenient diagnosis tool for the detection of P. knowlesi in remote settings.

Matched MeSH terms: Quinolines/chemistry*
Dietary exposure to heterocyclic amines in high-temperature cooked meat and fish in Malaysia

Jahurul MH, Jinap S, Ang SJ, Abdul-Hamid A, Hajeb P, Lioe HN, et al.

Food Addit Contam Part A Chem Anal Control Expo Risk Assess, 2010 Aug;27(8):1060-71.
PMID: 20589547 DOI: 10.1080/19440041003801190

The intake of heterocyclic amines is influenced by the amount and type of meat and fish ingested, frequency of consumption, cooking methods, cooking temperature, and duration of cooking. In this study, the dietary intake of heterocyclic amines in Malaysia and their main sources were investigated. Forty-two samples of meat and fish were analysed by high-performance liquid chromatography with photodiode array detector to determine the concentration of the six predominant heterocyclic amines, namely: 2-amino-3-methylimidazo[4,5-f] quinoline (IQ), 2-amino-3,4-dimethylimidazo[4,5-f] quinoline(MeIQ), 2-amino-3,8-dimethylimidazo[4,5-f] quinoxaline (MeIQx), 2-amino-3,4,8-trimethylimidazo[4,5-f] quinoxaline (4,8-DiMeIQx), 2-amino-3,7,8-trimethylimidazo[4,5-f] quinoxaline (7,8-DiMeIQx), and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). Dietary intake data were obtained using a food-frequency questionnaire when interviewing 600 Malaysian respondents. The level of total heterocyclic amines in food samples studies ranged from not detected to 38.7 ng g(-1). The average daily intake level of heterocyclic amine was 553.7 ng per capita day(-1). The intake of PhIP was the highest, followed by MeIQx and MeIQ. The results reveal that fried and grilled chicken were the major dietary source of heterocyclic amines in Malaysia. However, the heterocyclic amine intake by the Malaysian population was lower than those reported from other regions.

Matched MeSH terms: Quinolines/administration & dosage; Quinolines/analysis
Black sea cucumber (Holothuria atra Jaeger, 1833) rescues Pseudomonas aeruginosa-infected Caenorhabditis elegans via reduction of pathogen virulence factors and enhancement of host immunity

Lee WT, Tan BK, Eng SA, Yuen GC, Chan KL, Sim YK, et al.

Food Funct, 2019 Sep 01;10(9):5759-5767.
PMID: 31453615 DOI: 10.1039/c9fo01357a

A strategy to circumvent the problem of multidrug resistant pathogens is the discovery of anti-infectives targeting bacterial virulence or host immunity. Black sea cucumber (Holothuria atra) is a tropical sea cucumber species traditionally consumed as a remedy for many ailments. There is a paucity of knowledge on the anti-infective capacity of H. atra and the underlying mechanisms involved. The objective of this study is to utilize the Caenorhabditis elegans-P. aeruginosa infection model to elucidate the anti-infective properties of H. atra. A bioactive H. atra extract and subsequently its fraction were shown to have the capability of promoting the survival of C. elegans during a customarily lethal P. aeruginosa infection. The same entities also attenuate the production of elastase, protease, pyocyanin and biofilm in P. aeruginosa. The treatment of infected transgenic lys-7::GFP worms with this H. atra fraction restores the repressed expression of the defense enzyme lys-7, indicating an improved host immunity. QTOF-LCMS analysis revealed the presence of aspidospermatidine, an indole alkaloid, and inosine in this fraction. Collectively, our findings show that H. atra possesses anti-infective properties against P. aeruginosa infection, by inhibiting pathogen virulence and, eventually, reinstating host lys-7 expression.

Matched MeSH terms: Quinolines/pharmacology; Quinolines/chemistry
Fulltext Sustainable Syntheses of (-)-Jerantinines A & E and Structural Characterisation of the Jerantinine-Tubulin Complex at the Colchicine Binding Site

Smedley CJ, Stanley PA, Qazzaz ME, Prota AE, Olieric N, Collins H, et al.

Sci Rep, 2018 Jul 13;8(1):10617.
PMID: 30006510 DOI: 10.1038/s41598-018-28880-2

The jerantinine family of Aspidosperma indole alkaloids from Tabernaemontana corymbosa are potent microtubule-targeting agents with broad spectrum anticancer activity. The natural supply of these precious metabolites has been significantly disrupted due to the inclusion of T. corymbosa on the endangered list of threatened species by the International Union for Conservation of Nature. This report describes the asymmetric syntheses of (-)-jerantinines A and E from sustainably sourced (-)-tabersonine, using a straight-forward and robust biomimetic approach. Biological investigations of synthetic (-)-jerantinine A, along with molecular modelling and X-ray crystallography studies of the tubulin-(-)-jerantinine B acetate complex, advocate an anticancer mode of action of the jerantinines operating via microtubule disruption resulting from binding at the colchicine site. This work lays the foundation for accessing useful quantities of enantiomerically pure jerantinine alkaloids for future development.

Matched MeSH terms: Quinolines/isolation & purification; Quinolines/chemistry
Fulltext In-vitro activity of quinupristin/dalfopristin, levofloxacin and moxifloxacin against fusidic acid and rifampicin-resistant strains of methicillin-resistant Staphylococcus aureus (MRSA) from Malaysian hospitals

Norazah A, Lim VKE, Rohani MY, Kamel AGM

Med J Malaysia, 2005 Oct;60(4):411-5.
PMID: 16570701

The in-vitro susceptibility of quinupristin/dalfopristin, levofloxacin and moxifloxacin against methicillin-resistant Staphylococcus aureus (MRSA) strains, which are also resistant to fusidic acid and rifampicin were carried out to determine whether these antibiotics can be used as an alternative treatment for multiply resistant MRSA strains. The minimum inhibitory concentrations (MIC) of these antibiotics were determined by E-test. Quinupristin/dalfopristin had good activity (MIC90 = 1 mg/L) against these strains while most of the strains showed intermediate resistance to moxifloxacin with MIC90 = 2 mg/L). However, more than 90% of these strains were resistant to levofloxacin with the MICs that ranged from 8 mg/L to 16 mg/L with the majority inhibited at 8 mg/L.

Matched MeSH terms: Quinolines/pharmacology*
Fulltext Influence of the pfmdr1 Gene on In Vitro Sensitivities of Piperaquine in Thai Isolates of Plasmodium falciparum

Mungthin M, Watanatanasup E, Sitthichot N, Suwandittakul N, Khositnithikul R, Ward SA

Am J Trop Med Hyg, 2017 03;96(3):624-629.
PMID: 28044042 DOI: 10.4269/ajtmh.16-0668

Piperaquine combined with dihydroartemisinin is one of the artemisinin derivative combination therapies, which can replace artesunate-mefloquine in treating uncomplicated falciparum malaria in Thailand. The aim of this study was to determine the in vitro sensitivity of Thai Plasmodium falciparum isolates against piperaquine and the influence of the pfmdr1 gene on in vitro response. One hundred and thirty-seven standard laboratory and adapted Thai isolates of P. falciparum were assessed for in vitro piperaquine sensitivity. Polymorphisms of the pfmdr1 gene were determined by polymerase chain reaction methods. The mean and standard deviation of the piperaquine IC50 in Thai isolates of P. falciparum were 16.7 ± 6.3 nM. The parasites exhibiting chloroquine IC50 of ≥ 100 nM were significantly less sensitive to piperaquine compared with the parasite with chloroquine IC50 of < 100 nM. No significant association between the pfmdr1 copy number and piperaquine IC50 values was found. In contrast, the parasites containing the pfmdr1 86Y allele exhibited significantly reduced piperaquine sensitivity. Before nationwide implementation of dihydroartemisinin-piperaquine as the first-line treatment in Thailand, in vitro and in vivo evaluations of this combination should be performed especially in areas where parasites containing the pfmdr1 86Y allele are predominant such as the Thai-Malaysian border.

Matched MeSH terms: Quinolines/pharmacology*
Montelukast Reduces the Risk of Dengue Shock Syndrome in Dengue Patients

Ahmad A, Waseem T, Butt NF, Randhawa FA, Malik U, Shakoori TA

Trop Biomed, 2018 Dec 01;35(4):1115-1122.
PMID: 33601858

A significant percentage of dengue patients develop Dengue Shock Syndrome (DSS) which is characterized by increased vascular permeability, circulatory failure and often death. Montelukast, a cysteinyl leukotriene receptor antagonist regulates vascular permeability and we hypothesized that it may be effective in protecting against DSS. An open label, parallel, randomized controlled trial (RCT) was thus carried out at Mayo Hospital, Department of Medicine, Lahore. A total of 200 patients of dengue fever were recruited and randomized into two groups. The group A was treated with Montelukast 10 mg once daily for 5 days along with general supportive treatment. Group B received the standard supportive treatment and served as the control group. The frequency of DSS was compared in the two groups by Chi square test. A binary logistic regression analysis was conducted to assess the effects of montelukast treatment on onset of DSS after adjusting for gender, age, white cell count, platelet count, haematocrit, serum alanine transaminase (ALT) and aspartate transaminase (AST). Relative risk (RR), absolute risk reduction (ARR), relative risk reduction (RRR) and numbers needed to treat (NNT) were calculated. Significance level was set at p0.001, Odds ratio=5.01, 95% CI=2.17-11.60) even after adjusting for confounders. Montelukast reduced the absolute risk (ARR=22%) and the relative risk (RRR=71%) of DSS in dengue fever. Numbers needed to treat were 4.55. We thus conclude that treatment with oral montelukast may protect patients of dengue fever from DSS and greatly reduce mortality.

Matched MeSH terms: Quinolines
Quality of life assessment in patients with moderate to severe allergic rhinitis treated with montelukast and/or intranasal steroids: a randomised, double-blind, placebo-controlled study

Goh BS, Ismail MI, Husain S

J Laryngol Otol, 2014 Mar;128(3):242-8.
PMID: 24618303 DOI: 10.1017/S002221511400036X

This study investigated improvements in quality of life associated with eight weeks of montelukast and/or intranasal steroid treatment for moderate to severe allergic rhinitis.

Matched MeSH terms: Quinolines/therapeutic use*
Fulltext A Prospective Study on the Prevalence, Extent of Disease and Outcome of Eosinophilic Gastroenteritis in Patients Presenting with Lower Abdominal Symptoms

Hui CK, Hui NK

Gut Liver, 2018 May 15;12(3):288-296.
PMID: 29212311 DOI: 10.5009/gnl17056

Background/Aims: The epidemiology of eosinophilic gastroenteritis remains unclear. We aim to determine the prevalence of eosinophilic gastroenteritis in patients with lower abdominal symptoms.
Methods: In a prospective study, colonoscopy was performed on 2,469 consecutive patients. Biopsies were taken from the terminal ileum and ascending, transverse, descending and sigmoid colon in all patients.
Results: Sixty-four of the 2,469 patients (2.6%) had eosinophilic gastroenteritis. Only five of the 64 patients (7.8%) with eosinophilic gastroenteritis had endoscopic mucosal abnormalities during colonoscopy. Six of these 64 patients (9.4%) had severe disease at presentation, and seven of these 64 patients (10.9%) required systemic steroid treatment. An elevated absolute peripheral eosinophil count was independently associated with severe disease at presentation (4/6 [66.7%] vs 3/58 [5.2%], p=0.005; odds ratio [OR], 25.320; 95% confidence interval [CI], 2.628 to 243.910), and severe disease at the time of presentation was independently associated with the use of systemic steroid treatment (6/7 [85.7%] vs 0/57 [0%], p=0.008; OR, 18.021; 95% CI, 2.163 to 150.152).
Conclusions: The prevalence of eosinophilic gastroenteritis is common, and patients usually present normal-appearing mucosa on colonoscopy. Those with severe disease at presentation usually have a raised absolute peripheral eosinophil count and should be commenced on systemic steroids as an initial therapy.

Matched MeSH terms: Quinolines/administration & dosage
Fulltext A ruthenium polypyridyl intercalator stalls DNA replication forks, radiosensitizes human cancer cells and is enhanced by Chk1 inhibition

Gill MR, Harun SN, Halder S, Boghozian RA, Ramadan K, Ahmad H, et al.

Sci Rep, 2016 08 25;6:31973.
PMID: 27558808 DOI: 10.1038/srep31973

Ruthenium(II) polypyridyl complexes can intercalate DNA with high affinity and prevent cell proliferation; however, the direct impact of ruthenium-based intercalation on cellular DNA replication remains unknown. Here we show the multi-intercalator [Ru(dppz)2(PIP)](2+) (dppz = dipyridophenazine, PIP = 2-(phenyl)imidazo[4,5-f][1,10]phenanthroline) immediately stalls replication fork progression in HeLa human cervical cancer cells. In response to this replication blockade, the DNA damage response (DDR) cell signalling network is activated, with checkpoint kinase 1 (Chk1) activation indicating prolonged replication-associated DNA damage, and cell proliferation is inhibited by G1-S cell-cycle arrest. Co-incubation with a Chk1 inhibitor achieves synergistic apoptosis in cancer cells, with a significant increase in phospho(Ser139) histone H2AX (γ-H2AX) levels and foci indicating increased conversion of stalled replication forks to double-strand breaks (DSBs). Normal human epithelial cells remain unaffected by this concurrent treatment. Furthermore, pre-treatment of HeLa cells with [Ru(dppz)2(PIP)](2+) before external beam ionising radiation results in a supra-additive decrease in cell survival accompanied by increased γ-H2AX expression, indicating the compound functions as a radiosensitizer. Together, these results indicate ruthenium-based intercalation can block replication fork progression and demonstrate how these DNA-binding agents may be combined with DDR inhibitors or ionising radiation to achieve more efficient cancer cell killing.

Matched MeSH terms: Quinolines/toxicity