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A false-positive result with the American Society for Testing and Materials D5712-95 test method for protein given by a common vulcanization accelerator

Chen SF, Teoh SC, Porter M

J Allergy Clin Immunol, 1997 Nov;100(5):713-4.
PMID: 9389305
Matched MeSH terms: Guanidines*
Fulltext Nucleotide 1376 G-->T mutation in G6PD-deficient Chinese in Malaysia

Ainoon O, Joyce J, Boo NY, Cheong SK, Hamidah NH

Malays J Pathol, 1995 Dec;17(2):61-5.
PMID: 8935127

G6PD deficiency is the most common human enzymopathy and affects 200 million people worldwide. To date more than 400 biochemical variants and at least 60 different point mutations in the G6PD locus have been discovered. In Malaysia the overall incidence of G6PD deficiency among males is 3.1%, being more prevalent among the Chinese and Malays and less common among the Indians. As part of our initial effort to characterise G6PD deficiency in the Malaysian population, we investigated 18 G6PD deficient Chinese male neonates for the G6PD mutation G-->T at nt 1376, a common mutation seen among the Chinese in Taiwan and mainland China. The mutation was detected by a PCR-based technique using primers that artificially create a site for restriction enzyme Xho I. We found 61% (11 out of 18) of the Chinese G6PD deficient male neonates positive for this mutation. Study of enzyme electrophoretic mobility in 7 of the cases positive for this mutation revealed three different patterns of mobility. 107% (5 out of 7), 103% (1 out of 7) and 100% (1 out of 7). This study shows that mutation G-->T at nt 1376 is a common allele causing G6PD deficiency in Malaysians of Chinese origin. The finding of different patterns of electrophoretic mobility among the 7 cases positive for 1376 G-->T mutation supports the notion that diverse biochemical variants may share the same mutation.

Matched MeSH terms: Guanidines*; Guanidine
Cimetidine for chronic duodenal ulceration: short term clinical trial

Chelvam P, Zhmad Z

Med J Malaysia, 1979 Mar;33(3):274-6.
PMID: 392272
Matched MeSH terms: Guanidines/therapeutic use*
New One-Pot Synthesis of 1,3,5-Triazines: Three-Component Condensation, Dimroth Rearrangement, and Dehydrogenative Aromatization

Junaid A, Lim FPL, Tiekink ERT, Dolzhenko AV

ACS Comb Sci, 2019 07 08;21(7):548-555.
PMID: 31180634 DOI: 10.1021/acscombsci.9b00079

A new, effective one-pot synthesis of the 6, N2-diaryl-1,3,5-triazine-2,4-diamines under microwave irradiation was developed. The method involved an initial three-component condensation of cyanoguanidine, aromatic aldehydes, and arylamines in the presence of hydrochloric acid. Without isolation, the resulting 1,6-diaryl-1,6-dihydro-1,3,5-triazine-2,4-diamines were treated with a base to initiate Dimroth rearrangement and spontaneous dehydrogenative aromatization, affording the desired compounds. The developed method was found to be sufficiently general in scope, tolerating various aromatic aldehydes and amines; by using their combinations in the first step, a representative library of 110 compounds was successfully prepared and screened for anticancer properties.

Matched MeSH terms: Guanidines/pharmacology*; Guanidines/chemistry
Fulltext The best method for isolated total RNA from durian tissues

Ky, H., Yeap, S. K., Napis, S. B.

International Food Research Journal, 2012;19(3):1181-1183.
MyJurnal

Plant tissues, especially durian tissues contain high content of polysaccharides, polyphenols and other secondary metabolites which can co-precipitate with RNA causing problem in further transcriptomic study. In this experiment, three basic chaotic agents, CTAB, SDS and guanidine are used in three basic protocols for RNA isolation. The effectiveness of each method was determined by spectrophotometer, denaturing agarose gels analysis and northern blot hybridization. CTAB combining with additional sodium acetate precipitation step showed highest yield and best quality of isolated RNA which was free from contaminations of polysaccharides, polyphenols and other secondary metabolites. Furthermore, the total RNA from 4-month old durian flesh of clone D24 was successfully used to construct a cDNA library. In conclusion, CTAB method is effective to isolate total RNA on various types of durian tissues for further gene expression analysis.

Matched MeSH terms: Guanidines
Fulltext Docking Based 3D-QSAR Study of Tricyclic Guanidine Analogues of Batzelladine K As Anti-Malarial Agents

Ahmed N, Anwar S, Thet Htar T

Front Chem, 2017;5:36.
PMID: 28664157 DOI: 10.3389/fchem.2017.00036

The Plasmodium falciparum Lactate Dehydrogenase enzyme (PfLDH) catalyzes inter-conversion of pyruvate to lactate during glycolysis producing the energy required for parasitic growth. The PfLDH has been studied as a potential molecular target for development of anti-malarial agents. In an attempt to find the potent inhibitor of PfLDH, we have used Discovery studio to perform molecular docking in the active binding pocket of PfLDH by CDOCKER, followed by three-dimensional quantitative structure-activity relationship (3D-QSAR) studies of tricyclic guanidine batzelladine compounds, which were previously synthesized in our laboratory. Docking studies showed that there is a very strong correlation between in silico and in vitro results. Based on docking results, a highly predictive 3D-QSAR model was developed with q(2) of 0.516. The model has predicted r(2) of 0.91 showing that predicted IC50 values are in good agreement with experimental IC50 values. The results obtained from this study revealed the developed model can be used to design new anti-malarial compounds based on tricyclic guanidine derivatives and to predict activities of new inhibitors.

Matched MeSH terms: Guanidines
Molecular characterization of glycation-associated skin ageing: an alternative skin model to study in vitro antiglycation activity of topical cosmeceutical and pharmaceutical formulations

Lee KH, Ng YP, Cheah PS, Lim CK, Toh MS

Br J Dermatol, 2017 Jan;176(1):159-167.
PMID: 27363533 DOI: 10.1111/bjd.14832

BACKGROUND: Glycation is a nonenzymatic reaction that cross-links a sugar molecule and protein macromolecule to form advanced glycation products (AGEs) that are associated with various age-related disorders; thus glycation plays an important role in skin chronological ageing.
OBJECTIVES: To develop a novel in vitro skin glycation model as a screening tool for topical formulations with antiglycation properties and to further characterize, at the molecular level, the glycation stress-driven skin ageing mechanism.
METHODS: The glycation model was developed using human reconstituted full-thickness skin; the presence of N(ε) -(carboxymethyl) lysine (CML) was used as evidence of the degree of glycation. Topical application of emulsion containing a well-known antiglycation compound (aminoguanidine) was used to verify the sensitivity and robustness of the model. Cytokine immunoassay, quantitative real-time polymerase chain reaction and histological analysis were further implemented to characterize the molecular mechanisms of skin ageing in the skin glycation model.
RESULTS: Transcriptomic and cytokine profiling analyses in the skin glycation model demonstrated multiple biological changes, including extracellular matrix catabolism, skin barrier function impairment, oxidative stress and subsequently the inflammatory response. Darkness and yellowness of skin tone observed in the in vitro skin glycation model correlated well with the degree of glycation stress.
CONCLUSIONS: The newly developed skin glycation model in this study has provided a new technological dimension in screening antiglycation properties of topical pharmaceutical or cosmeceutical formulations. This study concomitantly provides insights into skin ageing mechanisms driven by glycation stress, which could be useful in formulating skin antiageing therapy in future studies.

Matched MeSH terms: Guanidines/metabolism
Susceptibility of highly pathogenic A(H5N1) avian influenza viruses to the neuraminidase inhibitors and adamantanes

Hurt AC, Selleck P, Komadina N, Shaw R, Brown L, Barr IG

Antiviral Res, 2007 Mar;73(3):228-31.
PMID: 17112602

Since 2003, highly pathogenic A(H5N1) influenza viruses have been the cause of large-scale death in poultry and the subsequent infection and death of over 140 humans. A group of 55 influenza A(H5N1) viruses isolated from various regions of South East Asia between 2004 and 2006 were tested for their susceptibility to the anti-influenza drugs the neuraminidase inhibitors and adamantanes. The majority of strains were found to be fully sensitive to the neuraminidase inhibitors oseltamivir carboxylate, zanamivir and peramivir; however two strains demonstrated increased IC50 values. Sequence analysis of these strains revealed mutations in the normally highly conserved residues 116 and 117 of the N1 neuraminidase. Sequence analysis of the M2 gene showed that all of the A(H5N1) viruses from Vietnam, Malaysia and Cambodia contained mutations (L26I and S31N) associated with resistance to the adamantane drugs (rimantadine and amantadine), while strains from Indonesia were found to be a mix of both adamantane resistant (S31N) and sensitive viruses. None of the A(H5N1) viruses from Myanmar contained mutations known to confer adamantane resistance. These results support the use of neuraminidase inhibitors as the most appropriate class of antiviral drug to prevent or treat human A(H5N1) virus infections.

Matched MeSH terms: Guanidines/pharmacology
Fulltext An overview of the characteristics of the novel avian influenza A H7N9 virus in humans

Tan KX, Jacob SA, Chan KG, Lee LH

Front Microbiol, 2015;6:140.
PMID: 25798131 DOI: 10.3389/fmicb.2015.00140

The novel avian influenza A H7N9 virus which caused the first human infection in Shanghai, China; was reported on the 31st of March 2013 before spreading rapidly to other Chinese provinces and municipal cities. This is the first time the low pathogenic avian influenza A virus has caused human infections and deaths; with cases of severe respiratory disease with pneumonia being reported. There were 440 confirmed cases with 122 fatalities by 16 May 2014; with a fatality risk of ∼28%. The median age of patients was 61 years with a male-to-female ratio of 2.4:1. The main source of infection was identified as exposure to poultry and there is so far no definitive evidence of sustained person-to-person transmission. The neuraminidase inhibitors, namely oseltamivir, zanamivir, and peramivir; have shown good efficacy in the management of the novel H7N9 virus. Treatment is recommended for all hospitalized patients, and for confirmed and probable outpatient cases; and should ideally be initiated within 48 h of the onset of illness for the best outcome. Phylogenetic analysis found that the novel H7N9 virus is avian in origin and evolved from multiple reassortments of at least four origins. Indeed the novel H7N9 virus acquired human adaptation via mutations in its eight RNA gene segments. Enhanced surveillance and effective global control are essential to prevent pandemic outbreaks of the novel H7N9 virus.

Matched MeSH terms: Guanidines