Science, medicine, and the future: Pharmacogenetics

Virtual screening study for biological activity assessment and metabolism pathway of a fuel dye in airborne exposure scenario

The utilization of synthetic dyes increases the risk to human health. Despite the progress of information on azo dyes, very little attention has been reported on toxicity assessment of anthraquinone dyes. Solvent Blue 35 (SB35) is one of the anthraquinone dyes likely to be encountered because of its increasing use in various industries. Whereas the design of laboratory tests is very expensive, in silico screening was used to predict the metabolic profile and toxicity effect of SB35. MetaTox software was used to predict the metabolites of phase I and II in two layers. Since airborne exposure has been considered, the pathways of inhalation and dermal absorption of SB35 were investigated through the SwissADME model based on the modified Lipinski's rule of five. To predict the biological effect and toxicity of SB35 and each of the metabolites, PASS online software was used. Chemical activity was considered according to the probability of activation values (Pa) higher than the probability of inactivation values (Pi). N- dealkylation of SB35 was predicted in the first layer, while seven active compounds were obtained in the second layer from phases I and II reactions. Investigating the physicochemical properties of SB35 confirmed inhalation absorption for occupational exposure scenarios. All metabolites are absorbed from intestinal routes based on the RO5 rules. SB35 and their metabolites have an effective substrate role for the sub-type of CYP 450 enzymes. The toxicity effect of carcinogenicity for SB35 and mutagenicity for metabolites are predicted while confirmed with some biological effects. However, reproductive disorders are pointed with SB35 by probability higher than 70%. Virtual screening methods are efficient tools for creating cost-effective predictions in the hazard's evaluation of SB35. However, a perspective view is suggested before decision-making for laboratory designing tests.

Pyrimidine Schiff Bases: Synthesis, Structural Characterization and Recent Studies on Biological Activities

Recently, 5-[(4-ethoxyphenyl)imino]methyl-N-(4-fluorophenyl)-6-methyl-2-phenylpyrimidin-4-amine has been synthesized, characterized, and evaluated for its antibacterial activity against Enterococcus faecalis in combination with antineoplastic activity against gastric adenocarcinoma. In this study, new 5-iminomethylpyrimidine compounds were synthesized which differ in the substituent(s) of the aromatic ring attached to the imine group. The structures of newly obtained pyrimidine Schiff bases were established by spectroscopy techniques (ESI-MS, FTIR and 1H NMR). To extend the current knowledge about the features responsible for the biological activity of the new 5-iminomethylpyrimidine derivatives, low-temperature single-crystal X-ray analyses were carried out. For all studied crystals, intramolecular N-H∙∙∙N hydrogen bonds and intermolecular C-H∙∙∙F interactions were observed and seemed to play an essential role in the formation of the structures. Simultaneously, their biological properties based on their cytotoxic features were compared with the activities of the Schiff base (III) published previously. Moreover, computational investigations, such as ADME prediction analysis and molecular docking, were also performed on the most active new Schiff base (compound 4b). These results were compared with the highest active compound III.

In silico Structure Prediction, Molecular Docking, and Dynamic Simulation of Plasmodium falciparum AP2-I Transcription Factor

Plasmodium falciparum Apicomplexan Apetala 2 Invasion (PfAP2-I) transcription factor (TF) is a protein that regulates the expression of a subset of gene families involved in P. falciparum red blood cell (RBC) invasion. Inhibiting PfAP2-I TF with small molecules represents a potential new antimalarial therapeutic target to combat drug resistance, which this study aims to achieve. The 3D model structure of PfAP2-I was predicted ab initio using ROBETTA prediction tool and was validated using Save server 6.0 and MolProbity. Computed Atlas of Surface Topography of proteins (CASTp) 3.0 was used to predict the active sites of the PfAP2-I modeled structure. Pharmacophore modeling of the control ligand and PfAP2-I modeled structure was carried out using the Pharmit server to obtain several compounds used for molecular docking analysis. Molecular docking and postdocking studies were conducted using AutoDock vina and Discovery studio. The designed ligands' toxicity predictions and in silico drug-likeness were performed using the SwissADME predictor and OSIRIS Property Explorer. The modeled protein structure from the ROBETTA showed a validation result of 96.827 for ERRAT, 90.2% of the amino acid residues in the most favored region for the Ramachandran plot, and MolProbity score of 1.30 in the 98th percentile. Five (5) best hit compounds from molecular docking analysis were selected based on their binding affinity (between -8.9 and -11.7 Kcal/mol) to the active site of PfAP2-I and were considered for postdocking studies. For the absorption, distribution, metabolism, elimination, and toxicity (ADMET) properties, compound MCULE-7146940834 had the highest drug score (0.63) and drug-likeness (6.76). MCULE-7146940834 maintained a stable conformation within the flexible protein's active site during simulation. The good, estimated binding energies, drug-likeness, drug score, and molecular dynamics simulation interaction observed for MCULE-7146940834 against PfAP2-I show that MCULE-7146940834 can be considered a lead candidate for PfAP2-I inhibition. Experimental validations should be carried out to ascertain the efficacy of these predicted best hit compounds.

Ethanol and Medical Psychotropics Co-Consumption in European Countries: Results from a Three-Year Retrospective Study of Forensic Samples in Spain

Ethanol and medical psychotropics (MPs) are legal psychoactive substances widely consumed in Western countries that are routinely detected in standard toxicological analyses at compulsory autopsies, and toxicokinetic interactions between these drugs have been described. However, studies assessing the consequences of this co-consumption are scarce in Europe. We performed a retrospective study on toxicological results from compulsory autopsies in Spain. Thirty-five legal psychotropics, including ethanol, were measured in blood samples from 380 decedents to assess the determinants of such co-consumption. MPs were detected in 42.4% of the subjects. Polypharmacy was frequent in our series (25%), being more frequent in men than in women. More than one-third of the decedents had detectable levels of ethanol, and a significant positive association between ethanol levels and age was evident. About one-third of MPs consumers were also co-consumers of ethanol. The simultaneous consumption of ethanol and MPs was higher in men than in women. Blood alcohol concentrations (BAC) were lower in men who consumed MPs. In polypharmacy deaths, there was a significant negative association between the number of MPs consumed and BAC in men (r = -0.097; p = 0.029). Our results showed a high prevalence of co-consumption of MPs and ethanol in the European population involved in medico-legal issues and suggest that toxicokinetic interactions may be lowering BAC in men. This is a very worrying result, as it could indicate that the legal blood ethanol limits set by legislation would not be appropriate for men on MPs treatment.

Design Two Novel Tetrahydroquinoline Derivatives against Anticancer Target LSD1 with 3D-QSAR Model and Molecular Simulation

Lysine-specific demethylase 1 (LSD1) is a histone-modifying enzyme, which is a significant target for anticancer drug research. In this work, 40 reported tetrahydroquinoline-derivative inhibitors targeting LSD1 were studied to establish the three-dimensional quantitative structure-activity relationship (3D-QSAR). The established models CoMFA (Comparative Molecular Field Analysis (q² = 0.778, Rpred2 = 0.709)) and CoMSIA (Comparative Molecular Similarity Index Analysis (q² = 0.764, Rpred2 = 0.713)) yielded good statistical and predictive properties. Based on the corresponding contour maps, seven novel tetrahydroquinoline derivatives were designed. For more information, three of the compounds (D1, D4, and Z17) and the template molecule 18x were explored with molecular dynamics simulations, binding free energy calculations by MM/PBSA method as well as the ADME (absorption, distribution, metabolism, and excretion) prediction. The results suggested that D1, D4, and Z17 performed better than template molecule 18x due to the introduction of the amino and hydrophobic groups, especially for the D1 and D4, which will provide guidance for the design of LSD1 inhibitors.

A Theory-Informed Systematic Review of Barriers and Enablers to Implementing Multi-Drug Pharmacogenomic Testing

PGx testing requires a complex set of activities undertaken by practitioners and patients, resulting in varying implementation success. This systematic review aimed (PROSPERO: CRD42019150940) to identify barriers and enablers to practitioners and patients implementing pharmacogenomic testing. We followed PRISMA guidelines to conduct and report this review. Medline, EMBASE, CINAHL, PsycINFO, and PubMed Central were systematically searched from inception to June 2022. The theoretical domain framework (TDF) guided the organisation and reporting of barriers or enablers relating to pharmacogenomic testing activities. From the twenty-five eligible reports, eleven activities were described relating to four implementation stages: ordering, facilitating, interpreting, and applying pharmacogenomic testing. Four themes were identified across the implementation stages: IT infrastructure, effort, rewards, and unknown territory. Barriers were most consistently mapped to TDF domains: memory, attention and decision-making processes, environmental context and resources, and belief about consequences.

Chemoinformatic Design and Profiling of Derivatives of Dasabuvir, Efavirenz, and Tipranavir as Potential Inhibitors of Zika Virus RNA-Dependent RNA Polymerase and Methyltransferase

Zika virus (ZIKV) infection is one of the mosquito-borne flaviviruses of human importance with more than 2 million suspected cases and more than 1 million people infected in about 30 countries. There are reported inhibitors of the zika virus replication machinery, but no approved effective antiviral therapy including vaccines directed against the virus for treatment or prevention is currently available. The study investigated the chemoinformatic design and profiling of derivatives of dasabuvir, efavirenz, and tipranavir as potential inhibitors of the zika virus RNA-dependent RNA polymerase (RdRP) and/or methyltransferase (MTase). The three-dimensional (3D) coordinates of dasabuvir, efavirenz, and tipranavir were obtained from the PubChem database, and their respective derivatives were designed with DataWarrior-5.2.1 using an evolutionary algorithm. Derivatives that were not mutagenic, tumorigenic, or irritant were selected; docked into RdRP and MTase; and further subjected to absorption, distribution, metabolism, excretion, and toxicity (ADMET) evaluation with Swiss-ADME and pkCSM web tools. Some of the designed compounds are Lipinski's rule-of-five compliant, with good synthetic accessibilities. Compounds 20d, 21d, 22d, and 1e are nontoxic with the only limitation of CYP1A2, CYP2C19, and/or CYP2C9 inhibition. Replacements of -CH₃ and -NH- in the methanesulfonamide moiety of dasabuvir with -OH and -CH₂- or -CH₂CH₂-, respectively, improved the safety/toxicity profile. Hepatotoxicity in 5d, 4d, and 18d is likely due to -NH- in their methanesulfonamide/sulfamic acid moieties. These compounds are potent inhibitors of N-7 and 2'-methylation activities of ZIKV methyltransferase and/or RNA synthesis through interactions with amino acid residues in the priming loop/"N-pocket" in the virus RdRP. Synthesis of these compounds and wet laboratory validation against ZIKV are recommended.

Computational and pharmacokinetics studies of 1,3-dimethylbenzimidazolinone analogues of new proposed agent against Alzheimer's disease

Background

Alzheimer's disease (AD) is a multifactorial disorder that gradually destroys wisdom and memory skills. Currently, this disease can only be treated palliatively. However, the molecular mechanisms underlying this condition remain elusive. Therefore, these treatments are inadequate. Current medications can only increase patient warning signs. Chemical structures were drawn using Chemsketch software. Spartan’14 software was used to optimize the structures using density functional theory (DFT). The PaDEL software was used to generate the descriptors. The genetic function algorithm (GFA) and multi-linear regression (MLR) approaches were used to generate the QSAR model.

Results

In the present study, we performed a computational investigation, molecular docking, and pharmacokinetics analysis of 1,3-dimethylbenzimidazolinone derivatives. The descriptors generated in the model are AATS7i, MATS5p, SpMin7_Bhe, and GATS6c. Compounds 13 and 21 have the best binding scores, 11.2 kcal/mol and 10.8 kcal/mol, respectively, and optimal protein–ligand interactions with AChE. These compounds have brilliant pharmacokinetic and physicochemical properties.

Conclusions

The model was validated and found to have good internal and external assessment parameters: R2 = 0.937, $$R_{{{\text{adj}}}}^{2}$$ R adj 2  = 0.863, $$Q_{{{\text{cv}}}}^{2}$$ Q cv 2  = 0.788, $$R_{{{\text{test}}}}^{2}$$ R test 2  = 0.756, LOF = 0.0268, $$cR_{{\text{p}}}^{2}$$ c R p 2  = 0.677. In summary, these data suggested that compounds 13 and 21 are promising multifunctional agents against AD.

Attachment Style Moderates Polygenic Risk for Incident Posttraumatic Stress in U.S. Military Veterans: A 7-Year, Nationally Representative, Prospective Cohort Study

BACKGROUND

Posttraumatic stress disorder (PTSD) develops consequent to complex gene-by-environment interactions beyond the precipitating trauma. To date, however, no known study has used a prospective design to examine how polygenic risk scores (PRSs) interact with social-environmental factors such as attachment style to predict PTSD development.

METHODS

PRSs were derived from a genome-wide association study of PTSD symptoms (N = 186,689; Million Veteran Program cohort). We evaluated combined effects of PRS and attachment style in predicting incident PTSD in a 7-year, nationally representative cohort of trauma-exposed, European-American U.S. military veterans without PTSD (N = 1083). We also conducted multivariate gene-by-environment interaction and drug repositioning analyses to identify loci that interact with multiple environmental factors and potential pharmacotherapies that may be repurposed for this disorder.

RESULTS

Veterans with higher PTSD PRS were more likely to have an incident-positive screen for PTSD over 7 years. A gene-by-environment interaction was also observed, such that higher PRS only predicted incident PTSD in veterans with an insecure attachment style and not those with a secure attachment style. At an individual locus level, the strongest gene-by-environment interaction was observed for the rs4702 variant of the FURIN gene with cumulative lifetime trauma burden. Drug repositioning revealed that genes implicated in PRS are perturbated by the drug doxylamine.

CONCLUSIONS

Attachment style moderates polygenic risk for the development of PTSD in European-American veterans. These findings may inform PTSD prevention and treatment for veterans with high polygenic risk for PTSD and suggest a potential pharmacotherapeutic target for risk genes moderated by social-environmental factors.

Pharmacogenomic testing in paediatrics: clinical implementation strategies

Pharmacogenomics (PGx) relates to the study of genetic factors determining variability in drug response. Implementing PGx testing in paediatric patients can enhance drug safety, helping to improve drug efficacy or reduce the risk of toxicity. Despite its clinical relevance, the implementation of PGx testing in paediatric practice to date has been variable and limited.

As with most paediatric pharmacological studies, there are well‐recognised barriers to obtaining high‐quality PGx evidence, particularly when patient numbers may be small, and off‐label or unlicensed prescribing remains widespread. Furthermore, trials enrolling small numbers of children can rarely, in isolation, provide sufficient PGx evidence to change clinical practice, so extrapolation from larger PGx studies in adult patients, where scientifically sound, is essential.

This review paper discusses the relevance of PGx to paediatrics and considers implementation strategies from a child health perspective. Examples are provided from Canada, the Netherlands and the UK, with consideration of the different healthcare systems and their distinct approaches to implementation, followed by future recommendations based on these cumulative experiences.

Improving the evidence base demonstrating the clinical utility and cost‐effectiveness of paediatric PGx testing will be critical to drive implementation forwards. International, interdisciplinary collaborations will enhance paediatric data collation, interpretation and evidence curation, while also supporting dedicated paediatric PGx educational initiatives. PGx consortia and paediatric clinical research networks will continue to play a central role in the streamlined development of effective PGx implementation strategies to help optimise paediatric pharmacotherapy.

Synthesis, Crystal Structure, and Biological Evaluation of Novel 5-Hydroxymethylpyrimidines

Pyrimidine displays a wide array of bioactivities, and thence, it is still considered a potent unit of new drug research. Its derivative, 5-hydroxymethylpyrimidine, can be found as a scaffold of nontypical nitrogen bases in DNA and as a core of some natural bioactive compounds. In this study, we obtained a series of 5-hydroxymethylpyrimidines that vary in the 4-position by the reduction of proper esters. All compounds were characterized by spectroscopic analysis, and single-crystal X-ray diffraction was performed for some of them. Biological investigations estimated cytotoxic properties against normal (RPTEC) and cancer (HeLa, HepaRG, Caco-2, AGS, A172) cell lines. It was found that the derivatives with an aliphatic amino group at the 4-position are generally less toxic to normal cells than those with a benzylsulfanyl group. Moreover, compounds with bulky constituents exhibit better anticancer properties, though at a moderate level. The specific compounds were chosen due to their most promising IC50 concentration for in silico study. Furthermore, antimicrobial activity tests were performed against six strains of bacteria and one fungus. They demonstrated that only derivatives with at least three carbon chain amino groups at the 4-position have weak antibacterial properties, and only the derivative with 4-benzylsulfanyl constituent exhibits any antifungal action.

Pharmacogenetics and Forensic Toxicology: A New Step towards a Multidisciplinary Approach

Pharmacogenetics analyzes the individual behavior of DNA genes after the administration of a drug. Pharmacogenetic research has been implemented in recent years thanks to the improvement in genome sequencing techniques and molecular genetics. In addition to medical purposes, pharmacogenetics can constitute an important tool for clarifying the interpretation of toxicological data in post-mortem examinations, sometimes crucial for determining the cause and modality of death. The purpose of this systematic literature review is not only to raise awareness among the forensic community concerning pharmacogenetics, but also to provide a workflow for forensic toxicologists to follow in cases of unknown causes of death related to drug use/abuse. The scientific community is called on to work hard in order to supply evidence in forensic practice, demonstrating that this investigation could become an essential tool both in civil and forensic contexts. The following keywords were used for the search engine: (pharmacogenetics) AND (forensic toxicology); (pharmacogenetics) AND (post-mortem); (pharmacogenetics) AND (forensic science); and (pharmacogenetics) AND (autopsy). A total of 125 articles were collected. Of these, 29 articles were included in this systematic review. A total of 75% of the included studies were original articles (n = 21) and 25% were case reports (n = 7). A total of 78% (n = 22) of the studies involved deceased people for whom a complete autopsy was performed, while 22% (n = 6) involved people in good health who were given a drug with a subsequent pharmacogenetic study. The most studied drugs were opioids (codeine, morphine, and methadone), followed by antidepressants (tricyclic antidepressants and venlafaxine). Furthermore, all studies highlighted the importance of a pharmacogenetics study in drug-related deaths, especially in cases of non-overdose of drugs of abuse. This study highlights the importance of forensic pharmacogenetics, a field of toxicology still not fully understood, which is of great help in cases of sudden death, deaths from overdose, deaths after the administration of a drug, and also in cases of complaint of medical malpractice.

iCYP-MFE: Identifying Human Cytochrome P450 Inhibitors Using Multitask Learning and Molecular Fingerprint-Embedded Encoding

The human cytochrome P450 (CYP) superfamily holds responsibilities for the metabolism of both endogenous and exogenous compounds such as drugs, cellular metabolites, and toxins. The inhibition exerted on the CYP enzymes is closely associated with adverse drug reactions encompassing metabolic failures and induced side effects. In modern drug discovery, identification of potential CYP inhibitors is, therefore, highly essential. Alongside experimental approaches, numerous computational models have been proposed to address this biochemical issue. In this study, we introduce iCYP-MFE, a computational framework for virtual screening on CYP inhibitors toward 1A2, 2C9, 2C19, 2D6, and 3A4 isoforms. iCYP-MFE contains a set of five robust, stable, and effective prediction models developed using multitask learning incorporated with molecular fingerprint-embedded features. The results show that multitask learning can remarkably leverage useful information from related tasks to promote global performance. Comparative analysis indicates that iCYP-MFE achieves three predominant tasks, one equivalent task, and one less effective task compared to state-of-the-art methods. The area under the receiver operating characteristic curve (AUC-ROC) and the area under the precision-recall curve (AUC-PR) were two decisive metrics used for model evaluation. The prediction task for CYP2D6-inhibition achieves the highest AUC-ROC value of 0.93 while the prediction task for CYP1A2-inhibition obtains the highest AUC-PR value of 0.92. The substructural analysis preliminarily explains the nature of the CYP-inhibitory activity of compounds. An online web server for iCYP-MFE with a user-friendly interface was also deployed to support scientific communities in identifying CYP inhibitors.

Nortriptyline for pain in knee osteoarthritis: a double-blind randomised controlled trial in New Zealand general practice

BACKGROUND

Osteoarthritis (OA) of the knee is a common cause of chronic pain. Analgesics that are currently available have limited efficacy and may be poorly tolerated. Tricyclic antidepressants are used as analgesics for other chronic conditions, but they have not been evaluated as analgesics in OA.

AIM

To investigate the analgesic efficacy of nortriptyline in people with knee OA.

DESIGN AND SETTING

A two-arm, parallel-group, 1:1, double-blind, randomised, placebo-controlled trial in Christchurch, New Zealand.

METHOD

Participants were recruited from orthopaedic outpatient clinics, primary care, and through public advertising. Adults with knee OA and a pain score of ≥20 points on the 50-point Western Ontario and McMaster University Osteoarthritis Index (WOMAC) pain subscale were randomised to receive either nortriptyline or identical placebo for 14 weeks. The primary outcome was knee pain at 14 weeks measured using the WOMAC pain subscale. Secondary outcomes included: function; stiffness; non-steroidal anti-inflammatory drug, opioid, and/or paracetamol use; each participant's global assessment; and adverse effects at 14 weeks.

RESULTS

Of the 205 randomised participants, 201 (98.0%) completed follow-up at 14 weeks. The baseline-adjusted mean WOMAC pain subscale score at week 14 was 6.2 points lower (95% confidence interval = -0.26 to 12.6, P = 0.06) in the nortriptyline arm versus the placebo arm. Differences in secondary outcomes generally favoured the nortriptyline arm, but were small and unlikely to be clinically relevant. However, the following were all more commonly reported by participants taking nortriptyline than those taking a placebo: dry mouth (86.9% versus 51.0%, respectively, P<0.001), constipation (58.6% versus 30.4%, respectively, P<0.001), and sweating (31.3% versus 20.6%, respectively, P = 0.033).

CONCLUSION

This study suggests nortriptyline does not significantly reduce pain in people with knee OA. The adverse effect profile was as expected.

Pharmacogenetics in psychiatric care, a call for uptake of available applications

In this narrative, we evaluate the role of pharmacogenetics in psychiatry from a pragmatic clinical perspective and address current barriers of clinical implementation of pharmacogenetics. Pharmacogenetics has been successfully implemented to improve drug therapy in several clinical areas, but not psychiatry. Yet, psychotropics account for more than one-third of the drugs for which pharmacogenetic guidelines are available and drug therapy in mental disorders is suboptimal with insufficient effectiveness and frequent adverse events. The limited application of pharmacogenetics in psychiatry is influenced by several factors; e.g. the complexity of psychotropic drug metabolism, possibly impeding the clinical understanding of the benefits of pharmacogenetics. Also, recommendations for most psychotropics classify pharmacogenetic testing only as (potentially) beneficial, not as essential, possibly because life-threatening adverse events are often not involved in these drug-gene interactions. Implementing pharmacogenetics in psychiatry could improve the current practice of time-consuming switching of therapies causing undue delays associated with worse outcomes. We expect pharmacogenetics in psychiatry to expedite with panel-based genotyping, including clinically relevant variants, which will address the complex enzymatic metabolism of psychotropic drugs. Until then, we stress that available pharmacogenetic testing should be seen as an integrated companion, not a competitor, in current clinical psychiatric care.

Open access in silico tools to predict the ADMET profiling of drug candidates

INTRODUCTION

We are in an era of bioinformatics and cheminformatics where we can predict data in the fields of medicine, the environment, engineering and public health. Approaches with open access in silico tools have revolutionized disease management due to early prediction of the absorption, distribution, metabolism, excretion, and toxicity (ADMET) profiles of the chemically designed and eco-friendly next-generation drugs.

AREAS COVERED

This review meticulously encompasses the fundamental functions of open access in silico prediction tools (webservers and standalone software) and advocates their use in drug discovery research for the safety and reliability of any candidate-drug. This review also aims to help support new researchers in the field of drug design.

EXPERT OPINION

The choice of in silico tools is critically important for drug discovery and the accuracy of ADMET prediction. The accuracy largely depends on the types of dataset, the algorithm used, the quality of the model, the available endpoints for prediction, and user requirement. The key is to use multiple in silico tools for predictions and comparing the results, followed by the identification of the most probable prediction.

Determinants of stakeholders' intention to adopt pharmacogenomic

Pharmacogenomics (PGx) testing, which aims to identify the genes that affect our responses to drugs, has been favoured by healthcare professionals as a means of maximising drug efficacy and improving the safety and cost-effectiveness of healthcare. Support from the public is needed to determine the successful development of this technology and its implementation in society. Therefore, the objective of this paper was to analyse factors that influence stakeholders' intentions to adopt pharmacogenomic testing in Malaysia. A validated instrument was administered through face-to-face interviews with a total of 421 adult respondents who were stratified according to 2 stakeholder groups: healthcare providers (n = 221) and patients/family members (n = 200). The data were then analysed using SPSS® version 24 software and the advanced multivariate statistical approach of Partial Least Square (PLS) path modelling in order to analyse the complex relationships among variables. Results of the studies indicated that the Malaysian stakeholders had a high amount of trust in the key players (mean score of 5.31), perceived high benefits (mean score of 5.53) and claimed to have high intentions of adopting PGx (mean score of 5.39). The majority of the predictors have significant direct relationships with the intention to adopt PGx, with the exception of moral concerns. Perceived benefits appeared to be the most important direct predictor of the intention to adopt PGx testing (ß = 0.371, P < 0.001) followed by trust in the key players (ß = 0.312, P < 0.001), engagement (ß = 0.272, P < 0.001) and religiosity (ß = 0.133, P < 0.01). In addition, perceived risks also had a direct negative association with the intention to adopt PGx (ß = -0.096, P < 0.05). At the same time, the perceived benefits also served as a mediator for all the other factors except risk. The results provide insights into the multidimensional nature of the determinants of the intention to adopt PGx testing in Malaysia. Although the results showed that the stakeholders in Malaysia were very positive towards PGx testing, they were also cautious about it. The predictors identified in this study can serve as indicators for social acceptance of PGx testing to facilitate the clinical research and implementation of PGx.

ADMET profiling of geographically diverse phytochemical using chemoinformatic tools

Aim: Phytocompounds are important due to their uniqueness, however, only few reach the development phase due to their poor pharmacokinetics. Therefore, preassessing the absorption, distribution, metabolism, excretion and toxicity (ADMET) properties is essential in drug discovery. Methodology: Biologically diverse databases (Phytochemica, SerpentinaDB, SANCDB and NuBBE_DB) covering the region of India, Brazil and South Africa were considered to predict the ADMET using chemoinformatic tools (Qikprop, pkCSM and DataWarrior). Results: Screening through each of pharmacokinetic criteria resulted in identification of 24 compounds that adhere to all the ADMET properties. Furthermore, assessment revealed that five have potent anticancer biological activity against cancer cell lines. Conclusion: We have established an open-access database (ADMET-BIS) to enable identification of promising molecules that follow ADMET properties and can be considered for drug development.

Clinical implications of psychiatric genetics in the new millennium – nightmare or nirvana?

We are on the verge of major advances in understanding the pathophysiology of major mental illnesses – including the likely discovery of several susceptibility genes for these conditions. For many this holds the prospect of a future in which improved prevention and better treatments will end the terror these conditions hold over so many lives (Farmer & Owen, 1996; Jones & Craddock, 1997, 1998). For others the vision is of a ‘brave new world‘, our futures mapped from birth by the genetic hand we have been dealt and in which those with mental illness will suffer increased stigma and discrimination (Rose, 1998). This debate (McGleenan, 1995) occurs in the dark shadow cast by the eugenic movements of the 19th and early 20th century (Galton, 1943) and the horrors to which they led (Hanauske-Abel, 1996; Seidelman, 1996). As we leave the decade of the brain and enter the new millennium it is an appropriate point to ask what advances are likely to occur and to consider the moral and ethical issues that will undoubtedly arise.

Evidence for models of diagnostic service provision in the community: literature mapping exercise and focused rapid reviews

Background

Current NHS policy favours the expansion of diagnostic testing services in community and primary care settings.

Objectives

Our objectives were to identify current models of community diagnostic services in the UK and internationally and to assess the evidence for quality, safety and clinical effectiveness of such services. We were also interested in whether or not there is any evidence to support a broader range of diagnostic tests being provided in the community.

Review methods

We performed an initial broad literature mapping exercise to assess the quantity and nature of the published research evidence. The results were used to inform selection of three areas for investigation in more detail. We chose to perform focused reviews on logistics of diagnostic modalities in primary care (because the relevant issues differ widely between different types of test); diagnostic ultrasound (a key diagnostic technology affected by developments in equipment); and a diagnostic pathway (assessment of breathlessness) typically delivered wholly or partly in primary care/community settings. Databases and other sources searched, and search dates, were decided individually for each review. Quantitative and qualitative systematic reviews and primary studies of any design were eligible for inclusion.

Results

We identified seven main models of service that are delivered in primary care/community settings and in most cases with the possible involvement of community/primary care staff. Not all of these models are relevant to all types of diagnostic test. Overall, the evidence base for community- and primary care-based diagnostic services was limited, with very few controlled studies comparing different models of service. We found evidence from different settings that these services can reduce referrals to secondary care and allow more patients to be managed in primary care, but the quality of the research was generally poor. Evidence on the quality (including diagnostic accuracy and appropriateness of test ordering) and safety of such services was mixed.

Conclusions

In the absence of clear evidence of superior clinical effectiveness and cost-effectiveness, the expansion of community-based services appears to be driven by other factors. These include policies to encourage moving services out of hospitals; the promise of reduced waiting times for diagnosis; the availability of a wider range of suitable tests and/or cheaper, more user-friendly equipment; and the ability of commercial providers to bid for NHS contracts. However, service development also faces a number of barriers, including issues related to staffing, training, governance and quality control.

Limitations

We have not attempted to cover all types of diagnostic technology in equal depth. Time and staff resources constrained our ability to carry out review processes in duplicate. Research in this field is limited by the difficulty of obtaining, from publicly available sources, up-to-date information about what models of service are commissioned, where and from which providers.

Future work

There is a need for research to compare the outcomes of different service models using robust study designs. Comparisons of ‘true’ community-based services with secondary care-based open-access services and rapid access clinics would be particularly valuable. There are specific needs for economic evaluations and for studies that incorporate effects on the wider health system. There appears to be no easy way of identifying what services are being commissioned from whom and keeping up with local evaluations of new services, suggesting a need to improve the availability of information in this area.

Funding

The National Institute for Health Research Health Services and Delivery Research programme.

Prevalence of Patients Using Drugs Metabolized by Cytochrome P450 2D6 in Different Populations: a Cross-Sectional Study

Background:

Despito a large number of studies investigating the potential clinical relevance of CYP2D6 genotyping in preventing treatment failure (eg, insufficient efficacy and/or unacceptable adverse effects), the prevalence of patients using drugs metabolized by that isoenzyme is relatively unknown.

Objective:

To investigate the prevalence of patients in different populations using drugs metabolized by CYP2D6.

Methods:

In this cross-sectional study. 6 different patient populations were investigated: general, general hospital, geriatric, psychogoriatric, psychiatric, and mentally retarded. From every population, 150 adults using at least one drug were randomly selected. Primary outcome was the prevalence of patients using at least one drug metabolized by CYP2D6. The prevalence of patients using at least one CYP2D6 substrate in different populations was compared with the general population using χ2 statistics. Data were expressed as a relative risk with a 95% confidence interval.

Results:

Patients from the general hospital (RR 1.81; 95% CI 1.26 to 2.62), geriatric patients (RR 2.16; 95% CI 1.26 to 2.62), psychogeriatric patients (RR 2.31; 95% CI 1.63 to 3.27), and psychiatric patients (RR 2.44; 95% CI 1.73 to 3.44) were treated more frequently with at least one drug metabolized by CYP2D6 compared with patients in the general population. Approximately 50% of psychiatric (52%), psychogeriatric (49%), and geriatric (46%) patients used at least one drug metabolized by CYP2D6. In total, 416 drugs metabolized by CYP2D6 were prescribed, with 257 (62%) of these classified as an antidepressant (Anatomical and Therapeutic Chemical [ATC] category N06A) or antipsychotic (ATC N05A).

Conclusions:

Several patient populations (eg, psychiatric, psychogeriatric, geriatric) have a high prevalence of patients treated with at least one drug metabolized by CYP2D6. This study does not provide evidence regarding the clinical evidence of CYP2D6 genotyping, but shows that, if CYP2D6 genotyping is relevant for patient care, the highest probability of cost-effectiveness will, most likely, be in specific populations.

Isa K, Salleh H, Teh LK, Salleh MZ. Detection of CYP2C19 Genetic Variants in Malaysian Orang Asli from Massively Parallel Sequencing Data

The human cytochrome P450 (CYP) is a superfamily of enzymes that have been a focus in research for decades due to their prominent role in drug metabolism. CYP2C is one of the major subfamilies which metabolize more than 10% of all clinically used drugs. In the context of CYP2C19, several key genetic variations that alter the enzyme’s activity have been identified and catalogued in the CYP allele nomenclature database. In this study, we investigated the presence of well-established variants as well as novel polymorphisms in the CYP2C19 gene of 62 Orang Asli from the Peninsular Malaysia. A total of 449 genetic variants were detected including 70 novel polymorphisms; 417 SNPs were located in introns, 23 in upstream, 7 in exons, and 2 in downstream regions. Five alleles and seven genotypes were inferred based on the polymorphisms that were found. Null alleles that were observed include CYP2C19*3 (6.5%), *2 (5.7%) and *35 (2.4%) whereas allele with increased function *17 was detected at a frequency of 4.8%. The normal metabolizer genotype was the most predominant (66.1%), followed by intermediate metabolizer (19.4%), rapid metabolizer (9.7%) and poor metabolizer (4.8%) genotypes. Findings from this study provide further insights into the CYP2C19 genetic profile of the Orang Asli as previously unreported variant alleles were detected through the use of massively parallel sequencing technology platform. The systematic and comprehensive analysis of CYP2C19 will allow uncharacterized variants that are present in the Orang Asli to be included in the genotyping panel in the future.

A pharmacist’s role in the individualization of treatment of HIV patients

The pharmacological treatment of HIV is complex and varies considerably among patients, as does the response of patients to therapy, requiring treatment plans that are closely tailored to individual needs. Pharmacists can take an active role in individualizing care by employing their knowledge of pharmacokinetics and pharmacogenetics and by interacting directly with patients in counseling sessions. These strategies promote the following: maintenance of plasma concentrations of antiretroviral agents within therapeutic ranges, prediction of pharmacological response of patients with certain genetic characteristics, and clinical control of HIV through the correct use of antiretroviral treatments. Together, these strategies can be used to tailor antiretroviral therapy to individual patients, thus improving treatment efficacy and safety.

Nortriptyline in knee osteoarthritis (NortIKA Study): study protocol for a randomised controlled trial

BACKGROUND

Osteoarthritis (OA) is a common cause of pain and disability. Currently available analgesics are often insufficiently effective or have unacceptable adverse effects. Tricyclic antidepressants may offer a useful centrally-acting analgesic. Nortriptyline is a readily-available, cheap and comparatively well-tolerated tricyclic antidepressant.

METHODS/DESIGN

We will conduct a parallel group, two-arm, participant and investigator-blinded, randomised controlled superiority trial comparing nortriptyline with placebo. Two hundred participants with primary knee OA will be enrolled. Participants will take study medication for 14 weeks. The primary outcome is difference between treatment arms in mean pain score measured on the Western Ontario and McMaster Universities (WOMAC) pain scale at 14 weeks.

DISCUSSION

This protocol describes the first randomised controlled trial of a tricyclic antidepressant in the treatment of OA. The results of the study may have significant implications for the management of this common and painful condition.

TRIAL REGISTRATION

The trial was registered with the Australian New Zealand Clinical Trials Registry on 27 June 2014. The trial registration number is: ACTRN12614000683639 .

Pharmacogenetics and the print media: what is the public told?

BACKGROUND

Pharmacogenetics is a rapidly growing field that aims to identify the genes that influence drug response. This science can be used as a powerful tool to tailor drug treatment to the genetic makeup of individuals. The present study explores the coverage of the topic of pharmacogenetics and its potential benefit in personalised medicine by the UK newsprint media.

METHODS

The LexisNexis database was used to identify and retrieve full text articles from the 10 highest circulation national daily newspapers and their Sunday equivalents in the UK. Content analysis of newspaper articles which referenced pharmacogenetic testing was carried out. A second researcher coded a random sample (21%) of newspaper articles to establish the inter-rater reliability of coding.

RESULTS

Of the 256 articles captured by the search terms, 96 articles (with pharmacogenetics as a major component) met the study inclusion criteria. The majority of articles over-stated the benefits of pharmacogenetic testing while paying less attention to the associated risks. Overall beneficial effects were mentioned 5.3 times more frequently than risks (p < 0.001). The most common illnesses for which pharmacogenetically based personalised medicine was discussed were cancer, cardiovascular disease and CNS diseases. Only 13% of newspaper articles that cited a specific scientific study mentioned this link in the article. There was a positive correlation between the size of the article and both the number of benefits and risks stated (P < 0.01).

CONCLUSION

More comprehensive coverage of the area of personalised medicine within the print media is needed to inform public debate on the inclusion of pharmacogentic testing in routine practice.

Factors affecting the anthelmintic efficacy of papaya latex in vivo: host sex and intensity of infection

The development of plant-derived cysteine proteinases, such as those in papaya latex, as novel anthelmintics requires that the variables affecting efficacy be fully evaluated. Here, we conducted two experiments, the first to test for any effect of host sex and the second to determine whether the intensity of the worm burden carried by mice would influence efficacy. In both experiments, we used the standard C3H mouse reference strain in which papaya latex supernatant (PLS) consistently shows >80 % reduction in Heligmosomoides bakeri worm burdens, but to broaden the perspective, we also included for comparison mice of other strains that are known to respond more poorly to treatment with papaya latex. Our results confirmed that there is a strong genetic influence affecting efficacy of PLS in removing adult worm burdens. However, there was no effect of host sex on efficacy (C3H and NIH) and no effect of infection intensity (C3H and BALB/c). These results offer optimism that plant-derived cysteine proteinases (CPs), such as these from papaya latex, can function as effective anthelmintics, with neither host sex nor infection intensity presenting further hurdles to impede their development for future medicinal and veterinary usage.

Combination analysis in genetic polymorphisms of drug-metabolizing enzymes CYP1A2, CYP2C9, CYP2C19, CYP2D6 and CYP3A5 in the Japanese population

The Cytochrome P450 is the major enzyme involved in drug metabolism. CYP enzymes are responsible for the metabolism of most clinically used drugs. Individual variability in CYP activity is one important factor that contributes to drug therapy failure. We have developed a new straightforward TaqMan PCR genotyping assay to investigate the prevalence of the most common allelic variants of polymorphic CYP enzymes CYP1A2, CYP2C9, CYP2C19, CYP2D6 and CYP3A5 in the Japanese population. Moreover, we focused on the combination of each genotype for clinical treatment. The genotype analysis identified a total of 139 out of 483 genotype combinations of five genes in the 1,003 Japanese subjects. According to our results, most of subjects seemed to require dose modification during clinical treatment. In the near future, modifications should be considered based on the individual patient genotype of each treatment.

A systematically combined genotype and functional combination analysis of CYP2E1, CYP2D6, CYP2C9, CYP2C19 in different geographic areas of mainland China--a basis for personalized therapy

The cytochrome P450 is the major enzyme involved in drug metabolism. Single CYP genotypes and metabolic phenotypes have been widely studied, but no combination analysis has been conducted in the context of specific populations and geographical areas. This study is the first to systematically analyze the combined genotypes and functional combinations of 400 samples of major CYP genes—CYP2E1, CYP2D6, CYP2C9, and CYP2C19 in four geographical areas of mainland China. 167 different genotype combinations were identified, of which 25 had a greater than 1% frequency in the Chinese Han population. In addition, phenotypes of the four genes for each sample were in line with the predictions of previous studies of the four geographical areas. On the basis of the genotype classification, we were able to produce a systemic functional combinations analysis for the population. 25 of the combinations detected had at least two non-wild phenotypes and four showed a frequency above 1%. A bioinformatics analysis of the relationship between particular drugs and multi-genes was conducted. This is the first systematic study to analyze genotype combinations and functional combinations across whole Chinese population and could make a significant contribution in the field of personalized medicine and therapy.

Pharmacogenetics of antiangiogenic and antineovascular therapies of age-related macular degeneration

Age-related macular degeneration (AMD), the most common age-related disease causing irreversible visual loss in industrialized countries, is a complex and multifactorial illness. Researchers have found components of the complement alternative pathway inside drusen and Bruch's membrane of AMD patients, underlying a possible important role of complement factor H in the pathogenesis of AMD. The neovascular (wet) AMD is the most destructive form and it is characterized by invasion of new blood vessels into subretinal spaces with subsequent exudation and bleeding, resulting in scarring of the macular region and loss of the central vision. The hallmark of the neovascular form is the choroidal neovascularization, where VEGF-A has an important role in the pathogenesis of the disease. SNPs of these genes have recently been investigated as potential pharmacogenetic markers of the antiangiogenic and antineovascular therapy of AMD, which includes verteporfin photodynamic therapy and anti-VEGF-A drugs, such as pegaptanib, bevacizumab and ranibizumab. The CFH rs1061170 CT and TT genotypes have been associated with an improvement of visual acuity in bevacizumab or ranibizumab treated patients, whereas patients harboring VEGF-A rs699946 G allele responded better to bevacizumab-based therapy if compared with patients carrying the A allele. In conclusion, the discovery of pharmacogenetic markers for the personalization of the antiangiogenic and/or antineovascular therapy could be, in the future, a key issue in ophthalmology to obtain a personalization of the therapy and to avoid unnecessary costs and adverse drug reactions.

Validation of tacrolimus equation to predict troughs using genetic and clinical factors

AIM

Tacrolimus is an immunosuppressant used in transplantation. This article reports the validation of the authors' recently developed genetics-based tacrolimus equation that predicts troughs.

METHODS

Validation was performed in an independent cohort of 795 kidney transplant recipients receiving tacrolimus. The performance of the equation to predict initial troughs was assessed by calculating the bias and precision of the equation. For all troughs in the first 6 months post-transplant, a comparison was made between the troughs predicted using the equation versus those predicted using a basic apparent clearance model with no covariates.

RESULTS

For initial troughs, the equation had a low bias (0.2 ng/ml) and high precision (1.8 ng/ml). For all troughs, the equation predicted troughs significantly better than the basic apparent clearance model.

CONCLUSION

The tacrolimus equation had good bias and precision in predicting initial troughs and performed better than a basic apparent clearance model for all the troughs.

Phase I study of TP300 in patients with advanced solid tumors with pharmacokinetic, pharmacogenetic and pharmacodynamic analyses

BACKGROUND

A Phase I dose escalation first in man study assessed maximum tolerated dose (MTD), dose-limiting toxicity (DLT) and recommended Phase II dose of TP300, a water soluble prodrug of the Topo-1 inhibitor TP3076, and active metabolite, TP3011.

METHODS

Eligible patients with refractory advanced solid tumors, adequate performance status, haematologic, renal, and hepatic function. TP300 was given as a 1-hour i.v. infusion 3-weekly and pharmacokinetic (PK) profiles of TP300, TP3076 and TP3011 were analysed. Polymorphisms in CYP2D6, AOX1 and UGT1A1 were studied and DNA strand-breaks measured in peripheral blood mononuclear cells (PBMCs).

RESULTS

32 patients received TP300 at 1, 2, 4, 6, 8, 10, 12 mg/m(2). MTD was 10 mg/m(2); DLTs at 12 (2/4 patients) and 10 mg/m(2) (3/12) included thrombocytopenia and febrile neutropenia; diarrhoea was uncommon. Six patients (five had received irinotecan), had stable disease for 1.5-5 months. TP3076 showed dose proportionality in AUC and Cmax from 1-10 mg/m(2). Genetic polymorphisms had no apparent influence on exposure. DNA strand-breaks were detected after TP300 infusion.

CONCLUSIONS

TP300 had predictable hematologic toxicity, and diarrhoea was uncommon. AUC at MTD is substantially greater than for SN38. TP3076 and TP3011 are equi-potent with SN38, suggesting a PK advantage.

TRIAL REGISTRATION

EU-CTR2006-001345-33.

Prediction of Cytochrome P450 Profiles of Environmental Chemicals with QSAR Models Built from Drug-like Molecules

The human cytochrome P450 (CYP) enzyme family is involved in the biotransformation of many xenobiotics. As part of the U.S. Tox21 Phase I effort, we profiled the CYP activity of approximately three thousand compounds, primarily those of environmental concern, against human CYP1A2, CYP2C19, CYP2C9, CYP2D6, and CYP3A4 isoforms in a quantitative high throughput screening (qHTS) format. In order to evaluate the extent to which computational models built from a drug-like library screened in these five CYP assays under the same conditions can accurately predict the outcome of an environmental compound library, five support vector machines (SVM) models built from over 17,000 drug-like compounds were challenged to predict the CYP activities of the Tox21 compound collection. Although a large fraction of the test compounds fall outside of the applicability domain (AD) of the models, as measured by k-nearest neighbor (k-NN) similarities, the predictions were largely accurate for CYP1A2, CYP2C9, and CYP3A4 ioszymes with area under the receiver operator characteristic curves (AUC-ROC) ranging between 0.82 and 0.84. The lower predictive power of the CYP2C19 model (AUC-ROC = 0.76) is caused by experimental errors and that of the CYP2D6 model (AUC-ROC = 0.76) can be rescued by rebalancing the training data. Our results demonstrate that decomposing molecules into atom types enhanced the coverage of the AD and that computational models built from drug-like molecules can be used to predict the ability of non-drug like compounds to interact with these CYPs.

An empirical examination of the management of return of individual research results and incidental findings in genomic biobanks

PURPOSE

The purpose of this study was to examine and document the management and return of individual research results and incidental findings to research participants among biobanks.

METHODS

A comprehensive Internet search was completed to identify biobanks and collect available documents about biobanks and their procedures and policies regarding the return of results. The Internet search was supplemented by an e-mail request to gather further such documents. A total of 2,366 documents were collected for analysis from a sample of 85 biobanks.

RESULTS

The major finding of this empirical work is that the majority of the biobanks in the sample do not address the return of individual research results and incidental findings in their publicly available documents.

CONCLUSION

The results suggest that there is a need for more discussion and guidance about the most appropriate ways for biobanks to consider the return of individual research results and incidental findings and generate policies and procedures that address this issue.

Predictive models for cytochrome p450 isozymes based on quantitative high throughput screening data

The human cytochrome P450 (CYP450) isozymes are the most important enzymes in the body to metabolize many endogenous and exogenous substances including environmental toxins and therapeutic drugs. Any unnecessary interactions between a small molecule and CYP450 isozymes may raise a potential to disarm the integrity of the protection. Accurately predicting the potential interactions between a small molecule and CYP450 isozymes is highly desirable for assessing the metabolic stability and toxicity of the molecule. The National Institutes of Health Chemical Genomics Center (NCGC) has screened a collection of over 17,000 compounds against the five major isozymes of CYP450 (1A2, 2C9, 2C19, 2D6, and 3A4) in a quantitative high throughput screening (qHTS) format. In this study, we developed support vector classification (SVC) models for these five isozymes using a set of customized generic atom types. The CYP450 data sets were randomly split into equal-sized training and test sets. The optimized SVC models exhibited high predictive power against the test sets for all five CYP450 isozymes with accuracies of 0.93, 0.89, 0.89, 0.85, and 0.87 for 1A2, 2C9, 2C19, 2D6, and 3A4, respectively, as measured by the area under the receiver operating characteristic (ROC) curves. The important atom types and features extracted from the five models are consistent with the structural preferences for different CYP450 substrates reported in the literature. We also identified novel features with significant discerning power to separate CYP450 actives from inactives. These models can be useful in prioritizing compounds in a drug discovery pipeline or recognizing the toxic potential of environmental chemicals.

[Pharmacogenetics]

Allergic reactions to drugs belong to the group of B-reactions, which are characterized not only by the pharmacologic profile of the drug but also by individual risk factors. Pharmacogenetic approaches facilitate identifying these risk factors. The most important example for Caucasian patients is NIDR (non-immediate drug reaction) to abacavir. Chinese patients possess risk factors for NIDR to allopurinol and anticonvulsants and the HLA locus on chromosome 6. Another potentially important area is assessing risk factors to prevent allergic reactions to antibiotics, especially with regard to the effective treatment of MRSA.

Prediction of cytochrome P450 isoform responsible for metabolizing a drug molecule

BACKGROUND

Different isoforms of Cytochrome P450 (CYP) metabolized different types of substrates (or drugs molecule) and make them soluble during biotransformation. Therefore, fate of any drug molecule depends on how they are treated or metabolized by CYP isoform. There is a need to develop models for predicting substrate specificity of major isoforms of P450, in order to understand whether a given drug will be metabolized or not. This paper describes an in-silico method for predicting the metabolizing capability of major isoforms (e.g. CYP 3A4, 2D6, 1A2, 2C9 and 2C19).

RESULTS

All models were trained and tested on 226 approved drug molecules. Firstly, 2392 molecular descriptors for each drug molecule were calculated using various softwares. Secondly, best 41 descriptors were selected using general and genetic algorithm. Thirdly, Support Vector Machine (SVM) based QSAR models were developed using 41 best descriptors and achieved an average accuracy of 86.02%, evaluated using fivefold cross-validation. We have also evaluated the performance of our model on an independent dataset of 146 drug molecules and achieved average accuracy 70.55%. In addition, SVM based models were developed using 26 Chemistry Development Kit (CDK) molecular descriptors and achieved an average accuracy of 86.60%.

CONCLUSIONS

This study demonstrates that SVM based QSAR model can predict substrate specificity of major CYP isoforms with high accuracy. These models can be used to predict isoform responsible for metabolizing a drug molecule. Thus these models can used to understand whether a molecule will be metabolized or not. This is possible to develop highly accurate models for predicting substrate specificity of major isoforms using CDK descriptors. A web server MetaPred has been developed for predicting metabolizing isoform of a drug molecule http://crdd.osdd.net/raghava/metapred/.

Abacavir/lamivudine combination in the treatment of HIV: a review

Abacavir has been at the center of research and clinical interest in the last two years. The frequency of the associated abacavir hypersensitivity syndrome has decreased substantially since the introduction of routine testing for the HLA-B*5701 allele; the activity of the drug in HIV-infected persons with HIV RNA values more than 100,000 copies/mL has been questioned; the possible increased risk of myocardial infarction after recent exposure to abacavir has been debated; and the drug has been moved from the “recommended” category to the “alternative” category in several guidelines. Still, the drug remains a useful agent in combination with other drugs, including lamivudine, for the treatment of HIV infection. This review will focus on the pharmacokinetics, activity, side effects, and resistance profile of both abacavir and lamivudine, including a thorough review of all of the recent studies relevant to both drugs.

Classical twin design in modern pharmacogenomics studies

Response to medication is highly variable, unpredictable and, at times, may be fatal. All drugs are more effective in certain groups of the population while showing no or minimal benefit in other groups. Although the current data on the subject are piecemeal, anecdotal evidence suggests that, in line with other common multifactorial traits, a myriad of genomic as well as environmental factors underpin population variability in drug response. Pharmacogenomics is the study of how variations in the human genome affect the variability in response to medication. Efforts to personalize treatment based on results from pharmacogenomics studies have the potential to increase efficacy, lower the overall cost of treatment, and decrease the incidence of adverse drug reactions, and are one of the major challenges of the modern era. The classical twin design has traditionally been used to assess the relative contribution of genetic and environmental factors to population variation in common, complex phenotypes, including drug response. Twins are not commonly regarded as providing the optimal design in genomic studies. However, we argue that, through their precise ‘matching’ for confounding variables (age, sex, cohort and common environmental effects), their amenability to numerous nonclassical study designs (genome-wide association studies or the role of epigenetic factors), and the availability of large, established registries worldwide, the twin model represents a flexible study design for systems-biology studies of drug response in humans. In this review, we describe the ‘classical twin model’ and its application in traditional pharmacogenetics studies, discuss the value of the twin design in the modern systems biology era, and highlight the potential of existing twin registries in formulating future strategies in pharmacogenomics research. We argue that the usefulness of this design goes beyond its traditional applications. Moreover, the flexibility of the model in concert with the amenability of large, established registries of twins worldwide to the collecting of new phenotypes will mean that the study of identical and nonidentical twins will play a considerable role in shaping our understanding of the important factors that underpin population variability in common, complex phenotypes, including response to medication.

Metoclopramide in the treatment of diabetic gastroparesis

Gastroparesis is a chronic disorder that affects a significant subset of the population. Diabetes mellitus is a risk factor for the development of gastroparesis. Currently, metoclopramide is the only US FDA-approved medication for the treatment of gastroparesis. However, the FDA recently placed a black-box warning on metoclopramide because of the risk of related side effects, including tardive dyskinesia, the incidence of which has been cited to be as high as 15% in the literature. This review will investigate the mechanisms by which metoclopramide improves the symptoms of gastroparesis and will focus on the evidence of clinical efficacy supporting metoclopramide use in gastroparesis. Finally, we seek to document the true complication risk from metoclopramide, especially tardive dyskinesia, by reviewing the available evidence in the literature. Potential strategies to mitigate the risk of complications from metoclopramide will also be discussed.