Systematic study of 1,2,3-triazolyl sterols for the development of new drugs against parasitic Neglected Tropical Diseases.

A series of thirty 1,2,3-triazolylsterols, inspired by azasterols with proven antiparasitic activity, were prepared by a stereocontrolled synthesis. Ten of these compounds constitute chimeras/hybrids of 22,26-azasterol (AZA) and 1,2,3-triazolyl azasterols. The entire library was assayed against the kinetoplastid parasites Leishmania donovani, Trypanosoma cruzi, and Trypanosoma brucei, the causatives agents for visceral leishmaniasis, Chagas disease, and sleeping sickness, respectively. Most of the compounds were active at submicromolar/nanomolar concentrations with high selectivity index, when compared to their cytotoxicity against mammalian cells. Analysis of in silico physicochemical properties were conducted to rationalize the activities against the neglected tropical disease pathogens. The analogs with selective activity against L. donovani (E4, IC50 0.78 µM), T brucei (E1, IC50 0.12 µM) and T. cruzi (B1- IC50 0.33 µM), and the analogs with broad-spectrum antiparasitic activities against the three kinetoplastid parasites (B1 and B3), may be promising leads for further development as selective or broad-spectrum antiparasitic drugs.

Expanding the scope of novel 1,2,3-triazole derivatives as new antiparasitic drug candidates.

We have previously shown that prenyl and aliphatic triazoles are interesting motifs to prepare new chemical entities for antiparasitic and antituberculosis drug development. In this opportunity a new series of prenyl-1,2,3-triazoles were prepared from isoprenyl azides and different alkynes looking for new antimalarial drug candidates. The compounds were prepared by copper(i) catalyzed dipolar cycloaddition of the isoprenyl azide equilibrium mixture providing exclusively 1,4-disubstituted 1,2,3-triazoles in a regiospecific fashion. The complete collection of 64 compounds was tested on chloroquine-sensitive (CQ sensitive), Sierra Leone (D6), and the chloroquine-resistant, Indochina (W2), strains of Plasmodium falciparum and those compounds which were not previously reported were also tested against Leishmania donovani, the causative agent for visceral leishmaniasis. Thirteen analogs displayed antimalarial activity with IC50 below 10 µM, while the antileishmanial activity of the newly reported analogs could not improve upon those previously reported. Compounds 1o and 1r were identified as the most promising antimalarial drug leads with IC50 below 3.0 µM for both CQ-sensitive and resistant P. falciparum strains with high selectivity index. Finally, a chemoinformatic in silico analysis was performed to evaluate physicochemical parameters, cytotoxicity risk and drug score. The validation of a bifunctional farnesyl/geranylgeranyl diphosphate synthase PfFPPS/GGPPS as the potential target of the antimalarial activity of selected analogs should be further investigated.

Quantitative analysis of primaquine and its metabolites in human urine using liquid chromatography coupled with tandem mass spectrometry.

Primaquine (PQ), a prototype 8-aminoquinoline (8-AQ) drug used to treat malaria, is rapidly metabolized into different inactive and active metabolites. Due to the hemolytic toxicity, the uses of PQ have been confined. To understand its overall metabolism and its relation to drug efficacy and toxicity, profiling of urine for the parent drug and its metabolites is important. The current study presents a convenient and rapid method for simultaneously quantifying primaquine (PQ) and its metabolites in human urine. A simple liquid-liquid extraction followed by chromatographic separation and quantification through ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed and validated to quantify PQ and its eleven metabolites in the urine of healthy human volunteers who received a single oral dose of PQ. The developed method separated fourteen analytes, including internal standards, within nine minutes of run time. The linearity of all analytes was suitable in the range of 1-500 ng/mL. The extraction recovery for all concentrations of analytes from urine was ranged from 90.1 to 112.9 %. The relative standard deviation for intra- and inter-day precision were < 9.8 and < 10.7 %, respectively. Along with PQ, its different metabolites were detected in urine. Primaquine-5,6-orthoquinone, the N-carbamoylglucuronide conjugate of PQ and carboxyprimaquine were the major metabolites found in urine. Significant enantiomeric differences in the urinary excretion profiles for PQ and metabolites were observed. This analytical method can be implemented in the pharmacokinetic analysis of PQ to explain its toxicity and clinical decision making.

Natural Products Inhibitors of Monoamine Oxidases-Potential New Drug Leads for Neuroprotection, Neurological Disorders, and Neuroblastoma.

Monoamine oxidase inhibitors (MAOIs) are an important class of drugs prescribed for treatment of depression and other neurological disorders. Evidence has suggested that patients with atypical depression preferentially respond to natural product MAOIs. This review presents a comprehensive survey of the natural products, predominantly from plant sources, as potential new MAOI drug leads. The psychoactive properties of several traditionally used plants and herbal formulations were attributed to their MAOI constituents. MAO inhibitory constituents may also be responsible for neuroprotective effects of natural products. Different classes of MAOIs were identified from the natural product sources with non-selective as well as selective inhibition of MAO-A and -B. Selective reversible natural product MAOIs may be safer alternatives to the conventional MAOI drugs. Characterization of MAO inhibitory constituents of natural products traditionally used as psychoactive preparations or for treatment of neurological disorders may help in understanding the mechanism of action, optimization of these preparations for desired bioactive properties, and improvement of the therapeutic potential. Potential therapeutic application of natural product MAOIs for treatment of neuroblastoma is also discussed.

IgG4-Related Sclerosing Cholangitis with Cholecystitis Mimicking Cholangiocarcinoma: A Case Report.

IgG4-related diseases are rare multisystem disorders involving salivary glands, retroperitoneum, pancreas, biliary tract, and liver. Isolated biliary strictures and gall bladder involvement are rare in such patients, and presentation with cholangitis and weight loss can misguide the diagnosis toward malignancy. Here, we report an interesting case of IgG4-related biliary stricture with gall bladder involvement, presented with cholangitis and weight loss. The initial symptoms and imaging were guided toward the malignant possibilities of cholangiocarcinoma and pancreatic carcinoma. However, endosonography, serology, and histopathology clinched the diagnosis of IgG4-related disease. The patient was managed without any biliary intervention and with antibiotics, steroids, and steroid-sparing agents. There was a relapse of disease during the steroids taper that improved after hiking its doses. The disease responded with medical management on follow-up. We demonstrated the effectiveness of steroid-sparing agents to treat IgG4-related diseases, especially to avert the steroid-related adverse effects. This case highlights the possible mislead for the diagnosis and delayed management of IgG4 disease due to shared clinical features with hepatobiliary malignancies and the effectiveness of noninvasive measures of management.

Comparative single dose pharmacokinetics and metabolism of racemic primaquine and its enantiomers in human volunteers.

Primaquine (PQ) is a racemic drug used in treatment of malaria for six decades. Recent studies suggest that the two enantiomers of PQ are differentially metabolized in animals, and this results in different pharmacological and toxicological profiles. The current study characterizes the pharmacokinetic (PK) properties, metabolism and tolerability of the individual enantiomers of PQ in healthy human volunteers with normal glucose-6-phosphate dehydrogenase (G6PD) activity. Two cohorts (at two dose levels), each with 18 subjects, participated in three study arms in a crossover fashion: a single dose of the (-)-R enantiomer (RPQ), a single dose of the (+)-S enantiomer (SPQ), and a single dose of racemic PQ (RSPQ). PQ and its key metabolites carboxyprimaquine (cPQ) and PQ-N-carbamoyl glucuronide (PQ-N-CG) were analyzed. Clear differences were observed in PK and metabolism of the two enantiomers. Relative PQ exposure was higher with SPQ as compared to RPQ. PQ maximum plasma concentration (Cmax) and area under the plasma concentration-time curve were higher for SPQ, while the apparent volume of distribution and total body clearance were higher for RPQ. Metabolism of the two enantiomers showed dramatic differences: plasma PQ-N-CG was derived solely from SPQ, while RPQ was much more efficiently converted to cPQ than was SPQ. Cmax of cPQ and PQ-N-CG were 10 and 2 times higher, respectively, than the parent drugs. The study demonstrates that the PK properties of PQ enantiomers show clear differences, and metabolism is highly enantioselective. Such differences in metabolism suggest potentially distinct toxicity profiles in multi-dose regimens, especially in G6PD-deficient subjects.

Comparative pharmacokinetics and tissue distribution of primaquine enantiomers in mice.

BACKGROUND: Primaquine (PQ) has been used for the radical cure of relapsing Plasmodium vivax malaria for more than 60 years. PQ is also recommended for prophylaxis and prevention of transmission of Plasmodium falciparum. However, clinical utility of PQ has been limited due to toxicity in individuals with genetic deficiencies in glucose 6-phosphate dehydrogenase (G6PD). PQ is currently approved for clinical use as a racemic mixture. Recent studies in animals as well as humans have established differential pharmacological and toxicological properties of the two enantiomers of PQ. This has been attributed to differential metabolism and pharmacokinetics of individual PQ enantiomers. The aim of the current study is to evaluate the comparative pharmacokinetics (PK), tissue distribution and metabolic profiles of the individual enantiomers in mice. METHODS: Two groups of 21 male Albino ND4 Swiss mice were dosed orally with 45 mg/kg of S-(+)-PQ and R-(-)PQ respectively. Each of the enantiomers was comprised of a 50:50 mixture of 12C- and 13C- stable isotope labelled species (at 6 carbons on the benzene ring of the quinoline core). Three mice were euthanized from each group at different time points (at 0, 0.5, 1, 2, 4, 8, 24 h) and blood was collected by terminal cardiac bleed. Liver, spleen, lungs, kidneys and brain were removed, extracted and analysed using UPLC/MS. The metabolites were profiled by tandem mass (MS/MS) fragmentation profile and fragments with 12C-13C twin peaks. Non-compartmental analysis was performed using the Phoenix WinNonLin PK software module. RESULTS: The plasma AUC0-last (µg h/mL) (1.6 vs. 0.6), T1/2 (h) (1.9 vs. 0.45), and Tmax (h) (1 vs. 0.5) were greater for SPQ as compared to RPQ. Generally, the concentration of SPQ was higher in all tissues. At Tmax, (0.5-1 h in all tissues), the level of SPQ was 3 times that of RPQ in the liver. Measured Cmax of SPQ and RPQ in the liver were about 100 and 40 times the Cmax values in plasma, respectively. Similar observations were recorded in other tissues where the concentration of SPQ was higher compared to RPQ (2× in the spleen, 6× in the kidneys, and 49× in the lungs) than in the plasma. CPQ, the major metabolite, was preferentially generated from RPQ, with higher levels in all tissues (> 10× in the liver, and 3.5× in the plasma) than from SPQ. The PQ-o-quinone was preferentially formed from the SPQ (> 4× compared to RPQ), with higher concentrations in the liver. CONCLUSION: These studies show that in mice, PQ enantiomers are differentially biodistributed and metabolized, which may contribute to differential pharmacologic and toxicity profiles of PQ enantiomers. The findings on higher levels of PQ-o-quinone in liver and RBCs compared to plasma and preferential generation of this metabolite from SPQ are consistent with the higher anti-malarial efficacy of SPQ observed in the mouse causal prophylaxis test, and higher haemolytic toxicity in the humanized mouse model of G6PD deficiency. Potential relevance of these findings to clinical use of racemic PQ and other 8-aminoquinolines vis-à-vis need for further clinical evaluation of individual enantiomers are discussed.

Novel preparation of bilirubin-encapsulated pluronic F-127 nanoparticles as a potential biomaterial for wound healing.

Cutaneous wounds deteriorate the health of patients and liable for high economic loss. Previous studies showed promising wound healing potentials of bilirubin, however, this macromolecule constrained with poor water solubility and skin penetration. In this study, Pluronic F-127, a non-ionic copolymer surfactant, was used for the encapsulation of the wound healing agent the bilirubin. With this strategy, spherical shaped bilirubin nanoparticles of ∼100-150 nm with zeta potential ranging from -13.43 ± 0.56 to -17.53 ± 0.43 mV were obtained. Topical applications of bilirubin nanoparticle (0.3%) on cutaneous wounds of rats showed promising wound healing in comparison with other topical treatments. This topical nano-formulation also modulates the cytokine and growth factor responses in the treated group. On day 7 of healing, bilirubin nanoparticles treatment significantly reduced TNF-α and increased IL-10 levels with increased VEGF and TGF-ß1 expressions. Simultaneously, prominent pro-healing activities could be observed histopathologically. These include increased blood vessels, reduced inflammatory cells, more myofibroblasts, increased deposition of collagen fibres, and early re-epithelialization. The changes were prominent in bilirubin nanoparticles (0.3%) treated group indicating better granulation tissue, quality of healing and wound maturity. In conclusion, the proposed new encapsulated bilirubin nanoparticles strategy significantly improved wound healing by modulation of cytokines and growth factors response in comparison with native bulk bilirubin. These observations support its potential as a novel biomaterial for wound healing in the future.

Missing data imputation on biomedical data using deeply learned clustering and L2 regularized regression based on symmetric uncertainty.

Big data era in healthcare led to the generation of high dimensional datasets like genomic datasets, electronic health records etc. One among the critical issues to be addressed in such datasets is handling incomplete data that may yield misleading results if not handled properly. Imputation is considered to be an effective way when the missing data rate is high. While imputation accuracy and classification accuracy are the two important metrics generally considered by most of the imputation techniques, high dimensional datasets such as genomic datasets motivated the need for imputation techniques that are also computationally efficient and preserves the structure of the dataset. This paper proposes a novel approach to missing data imputation in biomedical datasets using an ensemble of deeply learned clustering and L2 regularized regression based on symmetric uncertainty. The experiments are conducted with different proportion of missing data on both genomic and non-genomic biomedical datasets for different types of missingness pattern. Our proposed approach is compared with seven proven baseline imputation methods and two recently proposed imputation approaches. The results show that the proposed approach outperforms the other approaches considered in our experimentation in terms of imputation accuracy and computational efficiency despite preserving the structure of the dataset. Thus, the overall classification accuracy of the biomedical classification tasks is also improved when our proposed missing data imputation technique is used.

Comparative metabolism and tolerability of racemic primaquine and its enantiomers in human volunteers during 7-day administration.

Primaquine (PQ) is an 8-aminoquinoline antimalarial, active against dormant Plasmodium vivax hypnozoites and P. falciparum mature gametocytes. PQ is currently used for P. vivax radical cure and prevention of malaria transmission. PQ is a racemic drug and since the metabolism and pharmacology of PQ's enantiomers have been shown to be divergent, the objectives of this study were to evaluate the comparative tolerability and metabolism of PQ with respect to its two enantiomers in human volunteers in a 7 days' treatment schedule. Fifteen subjects with normal glucose-6-phosphate dehydrogenase (G6PDn) completed four arms, receiving each of the treatments, once daily for 7 days, in a crossover fashion, with a 7-14 days washout period in between: R-(-) enantiomer (RPQ) 22.5 mg; S-(+) enantiomer (SPQ) 22.5 mg; racemic PQ (RSPQ) 45 mg, and placebo. Volunteers were monitored for any adverse events (AEs) during the study period. PQ and metabolites were quantified in plasma and red blood cells (RBCs) by UHPLC-UV-MS/MS. Plasma PQ was significantly higher in SPQ treatment group than for RPQ. Carboxy-primaquine, a major plasma metabolite, was much higher in the RPQ treated group than SPQ; primaquine carbamoyl glucuronide, another major plasma metabolite, was derived only from SPQ. The ortho-quinone metabolites were also detected and showed differences for the two enantiomers in a similar pattern to the parent drugs. Both enantiomers and racemic PQ were well tolerated in G6PDn subjects with the 7 days regimen; three subjects showed mild AEs which did not require any intervention or discontinuation of the drug. The most consistent changes in G6PDn subjects were a gradual increase in methemoglobin and bilirubin, but these were not clinically important. However, the bilirubin increase suggests mild progressive damage to a small fraction of red cells. PQ enantiomers were also individually administered to two G6PD deficient (G6PDd) subjects, one heterozygous female and one hemizygous male. These G6PDd subjects showed similar results with the two enantiomers, but the responses in the hemizygous male were more pronounced. These studies suggest that although the metabolism profiles of individual PQ enantiomers are markedly different, they did not show significant differences in the safety and tolerability in G6PDn subjects.

Computationally Assisted Lead Optimization of Novel Potent and Selective MAO-B Inhibitors.

A series of dietary flavonoid acacetin 7-O-methyl ether derivatives were computationally designed aiming to improve the selectivity and potency profiles against monoamine oxidase (MAO) B. The designed compounds were evaluated for their potential to inhibit human MAO-A and -B. Compounds 1c, 2c, 3c, and 4c were the most potent with a Ki of 37 to 68 nM against MAO-B. Compounds 1c-4c displayed more than a thousand-fold selectivity index towards MAO-B compared with MAO-A. Moreover, compounds 1c and 2c showed reversible inhibition of MAO-B. These results provide a basis for further studies on the potential application of these modified flavonoids for the treatment of Parkinson's Disease and other neurological disorders.

Primaquine Loaded Solid Lipid Nanoparticles (SLN), Nanostructured Lipid Carriers (NLC), and Nanoemulsion (NE): Effect of Lipid Matrix and Surfactant on Drug Entrapment, in vitro Release, and ex vivo Hemolysis.

Primaquine (PQ), an 8-aminoquinoline antimalarial drug, has been widely used for the eradication of hypnozoites from the liver and, therefore, recognized as the radical cure of malaria. However, the clinical applications of PQ are restricted to patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency due to severe dose-related hemolytic side effects. Nanoparticle carriers have shown great potential in achieving higher PQ concentrations in the target site, thereby reducing dose-related systemic toxicity caused by non-specific exposure. This work aims to develop, compare, and evaluate three PQ-loaded lipid-based drug carriers including solid lipid nanoparticles (SLN), nanostructured lipid carriers (NLC), and nano-emulsions (NE). The optimized PQ-SLN, PQ-NLC, and PQ-NE had a particle size of 250 nm, a PDI range of 0.1 to 0.3, a zeta potential of - 30 mV, and entrapment efficiency of ~ 90%. All lipid formulations showed sustained release in both simulated gastric and intestinal fluids over 6 h. Four empirical models - including zero-order, Higuchi, Korsmeyer-Peppas, and Hixson-Crowell models - were tested to understand the drug release mechanisms of PQ-SLN, PQ-NLC, and PQ-NE. The model fitness was found to be the highest in the Korsmeyer-Peppas model for all the PQ-loaded lipid formulations (R2: 0.88-0.94). No significant changes were observed in the entrapment efficiency, particle size, and PDI of lipid formulations throughout 1 month of storage at 4 °C and 25 °C. PQ-SLN and PQ-NLC can be further lyophilized with cryoprotectants to improve long-term stability. Finally, the treatment of erythrocytes with PQ-SLN, PQ-NLC, and PQ-NE reduced erythrocyte hemolysis by approximately 4.5-fold compared to the free drug solution.

A hybrid feature selection model based on improved squirrel search algorithm and rank aggregation using fuzzy techniques for biomedical data classification.

Feature selection has gained its importance due to the voluminous nature of the data. Owing to the computational complexity of wrapper approaches, the poor performance of filtering techniques, and the classifier dependency of embedded approaches, hybrid approaches are more commonly used in feature selection. Hybrid approaches use filtering metrics to reduce the computational complexity of wrapper algorithms and are proved to yield better feature subset. Though filtering metrics select the features based on their significance, most of them are unstable and biased towards the metric used. Moreover, the choice of filtering metrics depends largely on the distribution of data and data types. Biomedical datasets contain features with different distribution and types adding to the complexity in the choice of filtering metric. We address this problem by proposing a stable filtering method based on rank aggregation in hybrid feature selection model with Improved Squirrel search algorithm for biomedical datasets. Our proposed model is compared with other well-known and state-of-the-art methods and the results prove that our model exhibited superior performance in terms of classification accuracy and computational time. The robustness of our proposed model is proved by conducting experiments on nine biomedical datasets and with three different classifiers.

Enantioselective Interactions of Anti-Infective 8-Aminoquinoline Therapeutics with Human Monoamine Oxidases A and B.

8-Aminoquinolines (8-AQs) are an important class of anti-infective therapeutics. The monoamine oxidases (MAOs) play a key role in metabolism of 8-AQs. A major role for MAO-A in metabolism of primaquine (PQ), the prototypical 8-AQ antimalarial, has been demonstrated. These investigations were further extended to characterize the enantioselective interactions of PQ and NPC1161 (8-[(4-amino-1-methylbutyl) amino]-5-[3, 4-dichlorophenoxy]-6-methoxy-4-methylquinoline) with human MAO-A and -B. NPC1161B, the (R)-(-) enantiomer with outstanding potential for malaria radical cure, treatment of visceral leishmaniasis and pneumocystis pneumonia infections is poised for clinical development. PQ showed moderate inhibition of human MAO-A and -B. Racemic PQ and (R)-(-)-PQ both showed marginally greater (1.2- and 1.6-fold, respectively) inhibition of MAO-A as compared to MAO-B. However, (S)-(+)-PQ showed a reverse selectivity with greater inhibition of MAO-B than MAO-A. Racemic NPC1161 was a strong inhibitor of MAOs with 3.7-fold selectivity against MAO-B compared to MAO-A. The (S)-(+) enantiomer (NPC1161A) was a better inhibitor of MAO-A and -B compared to the (R)-(-) enantiomer (NPC1161B), with more than 10-fold selectivity for inhibition of MAO-B over MAO-A. The enantioselective interaction of NPC1161 and strong binding of NPC1161A with MAO-B was further confirmed by enzyme-inhibitor binding and computational docking analyses. Differential interactions of PQ and NPC1161 enantiomers with human MAOs may contribute to the enantioselective pharmacodynamics and toxicity of anti-infective 8-AQs therapeutics.

Targeting Chikungunya Virus Replication by Benzoannulene Inhibitors.

A benzo[6]annulene, 4-(tert-butyl)-N-(3-methoxy-5,6,7,8-tetrahydronaphthalen-2-yl) benzamide (1a), was identified as an inhibitor against Chikungunya virus (CHIKV) with antiviral activity EC90 = 1.45 µM and viral titer reduction (VTR) of 2.5 log at 10 µM with no observed cytotoxicity (CC50 = 169 µM) in normal human dermal fibroblast cells. Chemistry efforts to improve potency, efficacy, and drug-like properties of 1a resulted in a novel lead compound 8q, which possessed excellent cellular antiviral activity (EC90 = 270 nM and VTR of 4.5 log at 10 µM) and improved liver microsomal stability. CHIKV resistance to an analog of 1a, compound 1c, tracked to a mutation in the nsP3 macrodomain. Further mechanism of action studies showed compounds working through inhibition of human dihydroorotate dehydrogenase in addition to CHIKV nsP3 macrodomain. Moderate efficacy was observed in an in vivo CHIKV challenge mouse model for compound 8q as viral replication was rescued from the pyrimidine salvage pathway.

Quantitative determination of primaquine-5,6-ortho-quinone and carboxyprimaquine-5,6-ortho-quinone in human erythrocytes by UHPLC-MS/MS.

The antimalarial drug primaquine (PQ) causes methemoglobinemia and hemolysis in individuals with a genetic deficiency of glucose 6-phosphate dehydrogenase. Reactive oxygen species (ROS) generated by redox cycling of the metabolite primaquine-5,6-orthoquinone (POQ) in erythrocytes has been attributed to be responsible for the toxicity of PQ. Carboxyprimaquine (CPQ), the major human plasma metabolite of PQ, can also form the analogous carboxyprimaquine-5,6-orthoquinone (CPOQ) metabolite, which can also generate ROS in erythrocytes by redox cycling, thus contributing to the hematotoxicity of this drug. In order to study these pathways and characterize such effects in vivo, methods are needed for characterization and quantification of POQ and CPOQ in human erythrocytes. The purpose of this work was to develop a validated method for the quantitative determination of CPOQ and POQ metabolites in human erythrocytes, suitable for clinical studies of PQ metabolism. Several liquid-liquid extraction methods using different organic solvents had been investigated. The solvent mixture of water-methanol-acetonitrile (9:9:5, v/v) was shown to yield the best results for the two analytes. Chromatographic analysis of POQ and CPOQ in human erythrocytes was achieved on a high strength silica (HSS) column and gradient elution (water and acetonitrile, both containing 0.1% formic acid) by ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS). Quantitative estimation of POQ and CPOQ was executed by monitoring ion pairs of m/z 260.23 > 175.03 and m/z 275.19 > 175.04, respectively. The method, which was validated for precision, accuracy, selectivity, and linearity, was successfully applied for the quantitative determination of POQ and CPOQ, the key metabolites of PQ in human erythrocytes in PQ clinical study.

Current investigations on clinical pharmacology and therapeutics of Glucose-6-phosphate dehydrogenase deficiency.

Glucose-6-phospate dehydrogenase (G6PD) deficiency is estimated to affect more than 400 million people world-wide. This X-linked genetic deficiency puts stress on red blood cells (RBC), which may be further augmented under certain pathophysiological conditions and drug treatments. These conditions can cause hemolytic anemia and eventually lead to multi-organ failure and mortality. G6PD is involved in the rate-limiting step of the pentose phosphate pathway, which generates reduced nicotinamide adenine dinucleotide phosphate (NADPH). In RBCs, the NADPH/G6PD pathway is the only source for recycling reduced glutathione and provides protection from oxidative stress. Susceptibility of G6PD deficient populations to certain drug treatments and potential risks of hemolysis are important public health issues. A number of clinical trials are currently in progress investigating clinical factors associated with G6PD deficiency, validation of new diagnostic kits for G6PD deficiency, and evaluating drug safety, efficacy, and pathophysiology. More than 25 clinical studies in G6PD populations are currently in progress or have just been completed that have been examined for clinical pharmacology and potential therapeutic implications of G6PD deficiency. The information on clinical conditions, interventions, purpose, outcome, and status of these clinical trials has been studied. A critical review of ongoing clinical investigations on pharmacology and therapeutics of G6PD deficiency should be highly important for researchers, clinical pharmacologists, pharmaceutical companies, and global public health agencies. The information may be useful for developing strategies for treatment and control of hemolytic crisis and potential drug toxicities in G6PD deficient patients.

Emergence and Re-emergence of Human Coronaviruses: Spike Protein as the Potential Molecular Switch and Pharmaceutical Target.

BACKGROUND: Recent emergence of COVID-19 caused by a new human coronavirus (CoV) strain (SARS-CoV-2), which originated from China, poses the future emergence of additional CoVs. In most of the cases of emergence of human CoVs, bats, palm civets, raccoon dogs and camels have been identified as the sources of human infections and as reservoir hosts. A review of comparative genomic and phenotypic characteristics of human CoV strains vis-à-vis their comparison with the corresponding animal isolates shall provide clues regarding the potential genomic, phenotypic and molecular factors responsible for host-switching, which may lead to prospective emergence and re-emergence of human CoV outbreaks in the future. METHODS: The seven known human strains of CoV were analyzed for the host and viral factors responsible for human outbreaks. The molecular factors responsible for host-susceptibility, virulence and pathogenesis were reviewed to predict the emergence and re-emergence of additional human CoV strains. CoV spike protein was evaluated as a potential viral receptor for host switching and the target for pharmaceutical design. RESULTS: A review of the factors associated with host-susceptibility, virulence and pathogenesis of seven known human CoV strains presents significant possibilities for the emergence of new CoV strain(s), leading to more human outbreaks. Continuous exposure of animals' handlers to the infected animals, environmental changes, improper sanitations, non-disposal of the solid waste and resumption of exotic animals markets provides favorable conditions for "host switching" and the emergence of new and potentially more virulent human CoV strains. Mutations in target genes (like spike protein), which facilitate the viral entry into the host-cells, provide a potential "molecular switch" for preferences of new host-receptors, genetic diversity, genetic-recombination and high virulence. Additionally, the clinical and environmental factors, asymptomatic carriers, the paucity of efficacious vaccines & therapeutics, inefficient disease management and infection control measures, lack of public awareness, and effective communication of information about more virulent human-adapted virus isolates are critical for the emergence of new and virulent SARS-CoV strains with high mortality and varied incubation period in the near future. Small molecules binding with conserved druggable regions of the CoV spike proteins may be effective against multiple strains of CoVs. CONCLUSION: High propensity of mutations and "molecular adaptations" in coronaviruses creates the hot spots and high potential for "host switching", leading to the emergence of more virulent strains of human CoVs. The public/global health agencies, medical communities and research scientists should be prepared for the emergence and re-emergence of new human CoV strain(s) leading to potential disease outbreaks. The inhibitors binding with conserved druggable regions of spike proteins from multiple strains CoV may have utility as broad-spectrum antiviral drugs to combat future emergence of CoVs.

A case of premature and recurrent myocardial infarction associated with ABCA.1 gene mutation.

Coronary heart disease (CHD) is the most important cause of cardiovascular death and when premature, it affects the most productive population of the community. Premature CHD usually has a specific etiology, which on diagnosis, might help in the secondary prevention in that individual. We report a case of young adult with recurrent myocardial infarction, who on evaluation had mildly reduced HDL and Protein C levels with elevated serum homocysteine. Clinical exome identified a possibly pathogenic variant of ABCA1 gene, associated with Tangier disease.