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Pantothenate (vitamin B5) is the precursor for the biosynthesis of the phosphopantetheine moiety of coenzyme A and acyl carrier protein, and is synthesised in Escherichia coli by four enzymic reactions. Ketopantoate hydroxymethyltransferase (KPHMT) and pantothenate synthetase (PtS) catalyse the first and last steps, respectively. Two genes encoding KPHMT and one for PtS were identified in the Arabidopsis thaliana genome, and cDNAs for all three genes were amplified by PCR. The cDNAs were able to complement their respective E. coli auxotrophs, demonstrating that they encoded functional enzymes. Subcellular localisation of the proteins was investigated using green fluorescent protein (GFP) fusions and confocal microscopy. The two KPHMT–GFP fusion proteins were targeted exclusively to mitochondria, whereas PtS–GFP was found in the cytosol. This implies that there must be transporters for pathway intermediates. KPHMT enzyme activity could be measured in purified mitochondria from both pea leaves and Arabidopsis suspension cultures. We investigated whether Arabidopsis encoded homologues of the remaining two pantothenate biosynthesis enzymes from E. coli, l-aspartate-α-decarboxylase (ADC) and ketopantoate reductase (KPR). No homologue of ADC could be identified using either conventional blast or searches with the program fugue in which the structure of the E. coli ADC was compared to all the annotated proteins in Arabidopsis. ADC also appears to be absent from the genome of the yeast, Saccharomyces cerevisiae, by the same criteria. In contrast, a putative Arabidopsis oxidoreductase with some similarity to KPR was identified with fugue. [ABSTRACT FROM AUTHOR]

The identification of relevant protein kinase–protein substrate partners remains a serious challenge on a genome-wide scale. The design and synthesis of a photo-activatable nucleotide reagent to crosslink protein kinases with their substrates is described in which an azido group is appended to the γ-phosphoryl and purine moieties of ATP. In the absence of UV, compounds of this class were shown to act as competitive inhibitors versus ATP and non-competitive inhibitors versus peptide substrate for the protein tyrosine kinase Csk, suggesting that they can form a ternary complex with kinase and protein substrate. In vitro experiments with protein kinases indicate the bifunctional reagent can induce covalent protein–protein crosslinking that is dependent on UV irradiation. That significant kinase–substrate crosslinking occurs is suggested by the fact that this crosslinking is competitively inhibited by ATP. The crosslinked adducts can be readily cleaved by phosphodiesterase which supports the model for crosslinking and provides a simple method to deconvolute the linked protein partners. [Copyright &y& Elsevier]

This study aims to evaluate the association between dolutegravir (DTG) pharmacokinetic parameters and weight changes in treatment-experienced people with HIV (PWHIV) from the Simpl'HIV study newly switched to a dual DTG-based regimen. We used multivariable linear regressions to evaluate the association between DTG pharmacokinetic parameters at week 48 (derived using an established model) and weight change between week 0 and week 48. We adjusted our model for potential confounders including CD4 nadir, female sex, African origin, age, weight at week 0 and presence of a non-nucleoside reverse transcriptase inhibitor-based regimen before switch to DTG. The analysis included data from 39 PWHIV. An average significant weight gain of 2.4 kg was observed between baseline and week 48. DTG plasma exposure was not significantly associated with weight gain, even after adjusting for potential confounders (P = .9). We found no significant association between DTG pharmacokinetic parameters and weight gain amongst PWHIV newly switched to a DTG-based dual regimen., (© 2021 British Pharmacological Society.)

Background Anacetrapib is the only cholesteryl ester transfer protein inhibitor proven to reduce coronary heart disease (CHD). However, its effects on reverse cholesterol transport have not been fully elucidated. Macrophage cholesterol efflux (CEC), the initial step of reverse cholesterol transport, is inversely associated with CHD and may be affected by sex as well as haptoglobin copy number variants among patients with diabetes mellitus. We investigated the effect of anacetrapib on CEC and whether this effect is modified by sex, diabetes mellitus, and haptoglobin polymorphism. Methods and Results A total of 574 participants with CHD were included from the DEFINE (Determining the Efficacy and Tolerability of CETP Inhibition With Anacetrapib) trial. CEC was measured at baseline and 24-week follow-up using J774 macrophages, boron dipyrromethene difluoride-labeled cholesterol, and apolipoprotein B-depleted plasma. Haptoglobin copy number variant was determined using an ELISA assay. Anacetrapib increased CEC, adjusted for baseline CEC, risk factors, and changes in lipids/apolipoproteins (standard β, 0.23; 95% CI, 0.05-0.41). This CEC-raising effect was seen only in men ( P interaction=0.002); no effect modification was seen by diabetes mellitus status. Among patients with diabetes mellitus, anacetrapib increased CEC in those with the normal 1-1 haptoglobin genotype (standard β, 0.42; 95% CI, 0.16-0.69) but not the dysfunctional 2-1/2-2 genotypes ( P interaction=0.02). Conclusions Among patients with CHD, anacetrapib at a dose linked to improved CHD outcomes significantly increased CEC independent of changes in high-density lipoprotein cholesterol or other lipids, with effect modification by sex and a novel pharmacogenomic interaction by haptoglobin genotype, suggesting a putative mechanism for reduced risk requiring validation.

Aims: The aims of this study were to characterize escitalopram pharmacokinetic profile, to identify factors influencing drug exposure, notably drug-drug interactions with antiretrovirals, and to simulate expected exposure under standard dosage regimen., Methods: A population pharmacokinetic analysis was performed using NONMEM. A total of 159 plasma concentration measurements were obtained from 39 human immunodeficiency virus (HIV)-infected and 71 uninfected psychiatric patients. The influence of age, weight, sex, HIV and psychiatric cohorts, racemic citalopram treatment, and comedications on oral clearance was examined. Simulations served to calculate the percentage of patients expected to be under- or over-exposed, considering established therapeutic targets (15-80 ng/mL)., Results: A 1-compartment model with first-order absorption and elimination described the data adequately. The average escitalopram clearance and volume of distribution were 23.1 L/h (interindividual variability 51%), and 920 L, respectively. Escitalopram disposition did not differ between HIV-infected and uninfected patients, and was not affected by antiretroviral treatments. Coadministration of at least 1 proton-pump inhibitor (CYP2C19 inhibitor) modestly influenced escitalopram elimination (clearance decreased by 19%), with limited clinical relevance. Model-based simulations showed that, under a standard regimen of 10 mg once daily, a significant proportion of patients (56%) might be under-exposed., Conclusion: The variability in escitalopram disposition is large and poorly explained by demographic, clinical and environmental covariates, thus suggesting a role for dosage individualization based on therapeutic drug monitoring in case of poor clinical response. Escitalopram disposition is modestly impacted by comedications and therefore no a priori dosage adjustments are needed in patients receiving antiretroviral treatments, including boosted regimens., (© 2019 The British Pharmacological Society.)

Purpose: To analyze and compare the stress distribution in an implant-retained overdenture complex using ball and Locator attachments of three heights by means of a 3D finite element analysis (FEA)., Materials and Methods: Six finite element models comprising an edentulous mandible with two interforaminal bone-level implants and ball attachments of heights 1 mm (A1), 3 mm (A3), and 5 mm (A5), and Locator attachments of heights 1 mm (B1), 3 mm (B3), and 5 mm (B5), were designed using ANSYS Workbench Software. Unilateral vertical (100 N) and oblique loads (100 N at 30° to the longitudinal axis of the implant in buccolingual direction) were applied. Average von Mises stress values were evaluated quantitatively and qualitatively., Results: Locator attachments showed lower stress values as compared to the ball attachments in all examined areas. The increase in the height of both resulted in increased stress values. Higher values were observed at the implant neck in all models, as compared to the body and the apex. The recorded stress was higher in the cortical bone as compared to the cancellous bone., Conclusions: Within the limitations of the study, Locator attachments demonstrated lesser and more homogenous stress distribution in the implant-overdenture complex in comparison to ball attachments. The stresses generated within the tissues increase with an increase in collar height of the attachment system and therefore, attachments should be as short as possible for more favorable stress transmission., (© 2018 by the American College of Prosthodontists.)