Cancerpharmacogenomics: the relevance of genetic profile in optimization drug therapy for azathiopurine and 5-Fluorouracil / Teh Lay Kek And Mohd Zaki Salleh

Introduction: Pharmacogenomic studies contribute to genetic information in preventing severe side effects of drugs. Genetic polymorphisms in drug metabolizing enzymes such as dihydropyrimidine dehydrogenase (DPD) had been associated with variable clinical outcomes in many commonly prescribed chemotherapy drugs including 5-Fluorouracil and irinotecan. Objectives: The review of literature had shed lights to the importance and possible impact of genetic polymorphism of DPYD and TPMT in individualization of drug therapy for 5-FU and thiopurines. However, there were no data reported for Malaysian. Current study thus aimed to explore the role of pharmacogenetics in personalized medicine in our own population. Materials and methods: Genotyping methods for DPYD and TPMT were developed using dHPLC and allele specific PCR respectively. 5-FU levels were measured in colorectal cancer patients using developed method. DNA from healthy volunteers and patients were screened. Results: Genotyping of DPYD had detected one reported mutation DPYD*5, two new mutations in exon 14 1823 T>C and 1827 G>A and one intronic reagion of exon 13, 13 IVS-11G>A with allele frequencies of 14.5%, .9.1%, 9.1% and 0.9% respectively. Genotyping for TPMT revealed 7 (7%) to be heterozygous for TPMT variant alleles. The predominant allele detected is TPMT*3C and is in concordance with previous studies done on Southeast Asian populations

Cancer pharmacogenomics: the relevance of genetic profile in optimization drug therapy for azathiopurine and 5-fluorouracil / Prof Madya Dr Teh Lay Kek and Prof Dr Mohd Zaki Salleh

Introduction: Pharmacogenomic studies contribute to genetic information in preventing severe side effects of drugs. Genetic polymorphisms in drug metabolizing enzymes such as dihydropyrimidine dehydrogenase (DPD) had been associated with variable clinical outcomes in many commonly prescribed chemotherapy drugs including 5-Fluorouracil and irinotecan. Objectives: The review of literature had shed lights to the importance and possible impact of genetic polymorphism of DPYD and TPMT in individualization of drug therapy for 5-FU and thiopurines. However, there were no data reported for Malaysian. Current study thus aimed to explore the role of pharmacogenetics in personalized medicine in our own population. Materials and methods: Genotyping methods for DPYD and TPMT were developed using dHPLC and allele specific PCR respectively. 5-FU levels were measured in colorectal cancer patients using developed method. DNA from healthy volunteers and patients were screened. Results: Genotyping of DPYD had detected one reported mutation DPYD*5, two new mutations in exon 14 1823 T>C and 1827 G>A and one intronic reagion of exon 13, 13 IVS-11G>A with allele frequencies of 14.5%, .9.1%, 9.1% and 0.9% respectively. Genotyping for TPMT revealed 7 (7%) to be heterozygous for TPMT variant alleles. The predominant allele detected is TPMT*3C and is in concordance with previous studies done on Southeast Asian populations

Single nucleotide polymorphism (SNPS) analysis of Mu-opioid receptors (OPRM1) using denaturing high performance liquid chromatography (DHPLC) among the intravenous drug users

Objectives: The genetic polymorphisms of OPRM1 among the intravenous drug users (IVDUs) and healthy controls were investigated and the risk of addiction in relation to OPRM1 was predicted. Methods: PCR-denaturing high performance liquid chromatography (DHPLC) method was developed to investigate SNPs in the coding regions of OPRM1 in 93 IVDUs and 100 healthy controls. Subjects were confirmed to be drug addicts and their personality was studied using validated Tridimensional Personality Questionnaires (TPQ). Results: Based on the results obtained, seven SNPs were detected; two of them were previously associated with addiction. Homozygous OPRM1:c.118GG and heterozygous OPRM1:c.118AG variants were found to have higher frequencies among the IVDUs and healthy controls. In addition, carriers of OPRM1:c.118G allele scored higher for novelty seeking (NS) and harm avoidance (HA) with more explorative, neurotic and uninhibited personalities. We identified a new variant of OPRM1:c.77C>G which is located at the N-terminus of the G-coupled protein receptor and possibly decreases the binding affinity of its ligands among the IVDUs. Conclusion: In conclusion, DHPLC allows the detection of new and existing variants of OPRM1. Genotyping of OPRM1:c.118A>G and assessment of personalities using TPQ provide valuable tools for determination of addiction risk

Transgenerational epigenetics in substance abuse: exploring the inheritable DNA methylation underlying the agressive behaviour and altered stress response. / Professor Dr Teh Lay Kek, Professor Dr Mohd Zaki Salleh and Dr. Richard Muhammad Johari James

Addiction is defined as a chronic, relapsing disease that is characterized by (1) compulsive behaviour to seek and take drug, (2) loss of control due to limited intake (3) emergence of negative emotional states (e.g., dysphoria, anxiety, irritability) when access to the drug is prevented (Koob and Le Moal, 1997). Addictive behaviours include a complex variety of symptoms, including loss of control over its use, compulsive use, continued use despite negative consequences, and drug cravings. Of the 20.5 million Americans 12 or older that had a substance use disorder in 2015, 2 million had a substance use disorder involving prescription pain relievers and 591,000 had a substance use disorder involving heroin (Center for Behavioral Health Statistics and Quality, 2016). It is estimated that 23% of individuals who use heroin develop opioid addiction (National Institute on Drug Abuse, 2014; Centers for Disease Control and Prevention, 2016). It is also a chronic relapsing disorder characterized by cycles of escalating drug exposure, intermittent episodes of withdrawal with or without maintained abstinence, and acute or chronic relapse to drug use. Heroin and morphine are more widely used than any other illicit opioids with 13,852 users in Malaysia alone. The profile of drug users detected in 2015 recorded that 97.97% of the addicts are male (Statistics of Drug Users in Malaysia, 2015). Psychiatric comorbidity is commonly found among individuals with addictive disorders. The addicted patients often suffer from anxiety disorders. Hodgson and colleagues (2016) has confirmed the shared genetic underpinnings of addiction and anxiety. Genomic loci that involved in the etiology of the comorbid disorders were found to be heritable. However, a phenotypical study on this inheritance was not yet studied. The association between heroin use and crime has been widely documented. Researchers have consistently found that a large proportion of the heroin-dependent population regularly engage in criminal activity (Inciardi and Chambers, 1972; Voss and Stephens, 1973). Kokkevi et al. (1993), for example, reported that 79% of a small community of heroin-dependent individuals had been arrested and 60% had been convicted for a criminal offence. Recurrent cycles of heroin use and abstinence are thought to cause neurobiological changes in brain regions associated with reward, motivation, stress, learning and executive function (Jentsch and Taylor 1999; Koob and Le Moal 2008; Kreek et al. 2009a,b; Le Merrer et al. 2009; Winstanley et al. 2010). Such changes are thought to persist across extended drug-free periods to alter an individual's response to drug re-exposure and contribute to subsequent escalation of drug use (i.e., relapse-like behaviour) (Dalley et al. 2005)

Hepatoprotective and antioxidant activities of Dicranopteris linearis leaf extract against paracetamol-induced liver intoxication in rats

Context: Dicranopteris linearis L. (Gleicheniaceae) leaves have been reported to exert hepatoprotective activity. Objective: The hepatoprotective and antioxidant effects of ethyl acetate partition of D. linearis (EADL) are investigated. Materials and methods: EADL was subjected to antioxidant and anti-inflammatory studies, and phytochemical analyses. In vivo study involved six groups (n = 6) of overnight fasted Sprague Dawley rats. The test solutions [10% DMSO (normal), 10% DMSO (negative), 200 mg/kg silymarin (positive) or EADL (50, 250 or 500 mg/kg)] were administered orally once daily for 7 consecutive days followed by oral vehicle (only for normal) or hepatotoxic induction using 3 g/kg paracetamol (PCM). Results: EADL exerted ≈ 90% radical scavenging effects based on the DPPH and superoxide anion radical scavenging assays, high antioxidant capacity in the oxygen radical absorbance capacity assay (≈ 555,000 units), high total phenolic content (≈ 350 mg GAE/100 g extract) (p < 0.05), but low anti-inflammatory effect. EADL also attenuated PCM-induced liver intoxication as indicated by reduced level of serum liver enzymes; increased activity of endogenous enzymatic antioxidant (superoxide dismutase – 8.3 vs. 4.0 U/g tissue; catalase – 119 vs. 52 U/g tissue) and; reduced level of lipid peroxidation marker (2.7 vs. 5.0 µM). Preliminary screening of EADL revealed the presence of saponins, tannins and flavonoids with further HPLC analysis demonstrating the presence of rutin and quercetin. Discussion and conclusion: EADL exerted hepatoprotective and antioxidant activities; thus, these data support the potential use of D. linearis as a new source for future hepatoprotective drug development

Antinociceptive activity of methanolic extract of Muntingia calabura leaves: further elucidation of the possible mechanisms

Background: Muntingia calabura (Elaecoparceae) is a medicinal plant traditionally used, particularly, by the Peruvian people to alleviate headache and cold, pain associated with gastric ulcers or to reduce the prostate gland swelling. Following the recent establishment of antinociceptive activity of M. calabura leaf, the present study was performed to further elucidate on the possible mechanisms of antinociception involved. Methods: The methanol extract of M. calabura (MEMC) was prepared in the doses of 100, 250 and 500 mg/kg. The role of bradykinin, protein kinase C, pottasium channels, and various opioid and non-opioid receptors in modulating the extract’s antinociceptive activity was determined using several antinociceptive assays. Results are presented as Mean ± standard error of mean (SEM). The one-way ANOVA test with Dunnett's multiple comparison was used to analyze and compare the data, with P < 0.05 as the limit of significance. Results: The MEMC, at all doses, demonstrated a significant (p < 0.05) dose-dependent antinociceptive activity in both the bradykinin- and phorbol 12-myristate 13-acetate (PMA)-induced nociception. Pretreatment of the 500 mg/kg MEMC with 10 mg/kg glibenclamide (an ATP-sensitive K+ channel inhibitor), the antagonist of μ-, δ- and κ-opioid receptors (namely 10 mg/kg β-funaltrexamine, 1 mg/kg naltrindole and 1 mg/kg nor-binaltorphimine), and the non-opioid receptor antagonists (namely 3 mg/kg caffeine (a non-selective adenosinergic receptor antagonist), 0.15 mg/kg yohimbine (an α2-noradrenergic antagonist), and 1 mg/kg pindolol (a β-adrenoceptor antagonist)) significantly (p < 0.05) reversed the MEMC antinociception. However, 10 mg/kg atropine (a non-selective cholinergic receptor antagonist), 0.15 mg/kg prazosin (an α1-noradrenergic antagonist) and 20 mg/kg haloperidol (a non-selective dopaminergic antagonist) did not affect the extract's antinociception. The phytochemicals screening revealed the presence of saponins, flavonoids, tannins and triterpenes while the HPLC analysis showed the presence of flavonoid-based compounds. Conclusions: The antinociceptive activity of MEMC involved activation of the non-selective opioid (particularly the μ-, δ- and κ-opioid) and non-opioid (particularly adenosinergic, α2-noradrenergic, and β-adrenergic) receptors, modulation of the ATP-sensitive K+ channel, and inhibition of bradikinin and protein kinase C actions. The discrepancies in MEMC antinociception could be due to the presence of various phytochemicals

A systematic review of the adverse effects of tacrolimus in organ transplant patients .

Tacrolimus has been the drug of choice for prevention of graft rejection following organ transplantations. This systematic review and meta-analysis [UiTM1] was conducted to evaluate the efficacy of tacrolimus in organ transplantation. Publication in English of randomized clinical trials, which used tacrolimus to prevent graft rejection in adult patients were included in this analysis. Articles were searched from PubMed, Science Direct, Blackwell and Ovid Gateway, which were published since 1980 to 2007. The outcomes measured were biopsy-proven acute rejection at three months; graft survival at one year; post-transplant diabetes mellitus; hypertension and neurotoxicity. Seven reports, which involved 2415 participants showed that tacrolimus was associated with reduced odds of biopsy-proven acute rejections three months of post-transplantation (pooled odds ratio of 0.69; 95% CI 0.49 to 0.96) and improved graft survival at one year (pooled odds ratio of 1.11 and 95% confidence interval 0.72 to 1.71). In terms of adverse effects, tacrolimus-treated patients were significantly at high odds of developing post-transplant diabetes mellitus (pooled odds ratio of 1.90; 95% CI 1.09 to 3.30) and neurotoxicity (pooled odds ratio of 1.61; 95% CI 1.15 to 2.25) but reduced odds of developing hypertension (pooled odds ratio of 0.80; 95% CI 0.65 to 0.98). Low to moderate heterogeneity between trials existed for the incidences of biopsy-proven acute rejections, graft survival, post-transplant diabetes mellitus and incidence of hypertension; but the analysis showed a significant increment of neurotoxicity by tacrolimus

Mutational analysis of CYP2C8 in hypertensive patients using denaturing high performance liquid chromatography.

What is known and Objective: CYP2C8 is involved in the cytochrome P450 (CYP) epoxygenase pathway. Arachidonic acid metabolites such as epoxyeicosatrienenoic acids and hydroxyeicosatetrenoic acids, produced may have a role in hypertension. We aimed to develop a medium through-put method for screening samples of known and new mutations of CYP2C8 using denaturing high performance liquid chromatography (DHPLC). Methods: DNA samples from 200 subjects (hypertensive patients and healthy controls) were screened for SNPs in CYP2C8 using DHPLC. Genotypes and allelic frequencies of CYP2C8 between the healthy controls and patients with hypertension were compared. Results and Discussions: Six variants were detected and two were new; T deletion at 5063 and substitution of C to T at 33468 in exon 8. Differences in variant frequencies were detected between the controls and hypertensive patients. The controls have significantly higher prevalence of C35322C compared to the patients. The functional significance of the SNP at 35322 requires further study. Having homozygous C35322C could be a protective factor for hypertension. What is new and Conclusion: Denaturing high performance liquid chromatography is useful for population screening to identify new and existing SNPs. A higher frequency of the C35322T SNP was observed among hypertensive patients than control subjects. This potentially important observation requires confirmation and the clinical significance assessed

In vivo antinociceptive and anti-inflammatory activities of dried- and fermented-processed virgin coconut oil.

Objective: The present study was carried out to investigate the antinociceptive and anti-inflammatory activities of virgin coconut oil (VCO) produced by theMalaysian Agriculture Research and Development Institute (MARDI) using various in vivo models. Materials and Methods: Two types of VCOs, produced via standard drying (VCOA) and fermentation (VCOB) processes were used in this study. Both VCOA and VCOB were serially diluted using 1% Tween 80 to concentrations (v/v) of 10, 50 and 100%. Antinociceptive and anti- inflammatory activities of both VCOs were examined using various in vivomodel systems. The antinociceptive activity of the VCOs were compared to those of 1% Tween 80 (used as a negative control), morphine (5 mg/kg) and/or acetylsalicylic acid (100 mg/kg). Results: Both VCOA and VCOB exhibited significant (p < 0.05) dose-dependent antinociceptive activity in the acetic acid-induced writhing test. Both VCOs also exerted significant (p < 0.05) antinociceptive activity in both phases of the formalin and hot-plate tests. Interestingly, the VCOs exhibited anti-inflammatory activity in an acute (carrageenan-induced paw edema test), but not in a chronic (cotton-pellet-induced granuloma test) model of inflammation. Conclusion: The MARDI-produced VCOs possessed antinociceptive and anti-inflammatory activities. Further studies are needed to confirm these observations