Infection imaging using [18F]FDG-labelled white blood cell positron emission tomography–computed tomography

Localizing the sites of infection in the body is possible in nuclear medicine using a variety of radiopharmaceuticals that target different components of the infective and inflammatory cascade. Gamma(γ)-emitting agents such as [67Ga]gallium citrate were among the first tracers used, followed by development of positron-emitting tracers like 2-deoxy-2-[18F]fluoro-D-glucose (¹⁸F-FDG). Though these tracers are quite sensitive, they have limited specificity for infection due to their concentration in sites of non-infective inflammation. White blood cells (WBC) labelled with γ or positron emitters have higher accuracy for differentiating the infective processes from the non-infective conditions that may show positivity with tracers such as ¹⁸F-FDG. We present a pictorial review of potential clinical applications of PET/CT using ¹⁸F-FDG labelled WBC.     

Store–Operated Ca2+ Channels in Mesangial Cells Inhibit Matrix Protein Expression

Accumulation of extracellular matrix derived from glomerular mesangial cells is an early feature of diabetic nephropathy. Ca²⁺ signals mediated by store–operated Ca²⁺ channels regulate protein production in a variety of cell types. The aim of this study was to determine the effect of store–operated Ca²⁺ channels in mesangial cells on extracellular matrix protein expression. In cultured human mesangial cells, activation of store–operated Ca²⁺ channels by thapsigargin significantly decreased fibronectin protein expression and collagen IV mRNA expression in a dose-dependent manner. Conversely, inhibition of the channels by 2-aminoethyl diphenylborinate significantly increased the expression of fibronectin and collagen IV. Similarly, overexpression of stromal interacting molecule 1 reduced, but knockdown of calcium release–activated calcium channel protein 1 (Orai1) increased fibronectin protein expression. Furthermore, 2-aminoethyl diphenylborinate significantly augmented angiotensin II–induced fibronectin protein expression, whereas thapsigargin abrogated high glucose– and TGF-β1–stimulated matrix protein expression. In vivo knockdown of Orai1 in mesangial cells of mice using a targeted nanoparticle siRNA delivery system resulted in increased expression of glomerular fibronectin and collagen IV, and mice showed significant mesangial expansion compared with controls. Similarly, in vivo knockdown of stromal interacting molecule 1 in mesangial cells by recombinant adeno–associated virus–encoded shRNA markedly increased collagen IV protein expression in renal cortex and caused mesangial expansion in rats. These results suggest that store–operated Ca²⁺ channels in mesangial cells negatively regulate extracellular matrix protein expression in the kidney, which may serve as an endogenous renoprotective mechanism in diabetes.     

Improvements in health-related quality of life after treatment with tocilizumab in patients with rheumatoid arthritis refractory to tumour necrosis factor inhibitors: results from the 24-week randomized controlled RADIATE study

Objective. To investigate the effect of tocilizumab on patient-reported outcomes (PROs) in RA patients with inadequate responses to TNF inhibitors (TNFis). Methods. In a Phase III randomized controlled trial, 489 patients received 4 or 8 mg/kg tocilizumab or placebo every 4 weeks plus MTX for 24 weeks. Mean changes from baseline over time and proportions of patients reporting improvements greater than or equal to minimum clinically important differences (MCIDs) in PROs were analyzed. Results. At week 24, 8?mg/kg resulted in significantly greater improvements vs placebo in pain, global assessment of disease activity (P?=?0.001), Health Assessment Questionnaire-Disability Index (HAQ-DI; P?相似文献   

Bioactivity guided fractionation of methanolic extract of Terminalia arjuna for its CYP3A and CYP2D inhibition in rat liver microsomes

Terminalia arjuna (T. arjuna) is an Indian medicinal plant belonging to the family Combretaceae and possesses numerous therapeutic activities including its immense cardioprotective activity. In the present work, a methanolic bark extract of T. arjuna was evaluated for CYP3A and CYP2D inhibition potential in rat liver microsomes (RLM). Further, the methanolic bark extract was fractionated successively using increasing polarity solvents starting with petroleum ether, chloroform, ethyl acetate and n‐butanol. The fractions so obtained were also evaluated for their CYP3A and CYP2D inhibition potential. Probe substrates testosterone and dextromethorphan were used for CYP3A and CYP2D respectively. The IC₅₀ values for the methanolic extract and the fractions were found to be less than 50 μg/ml in RLM for both CYP3A and CYP2D isoenzymes. The most potent n‐butanol fraction was further fractionated with column chromatography to isolate the highest active constituent responsible for the activity. Fraction 4 of the n‐butanol extract was the most potent fraction with IC₅₀ values of 5.64 ± 0.735 μg/ml and 16.63 ± 0.879 μg/ml for CYP3A and CYP2D in RLM, respectively. Therefore, in vitro data indicated that the Terminalia arjuna extract contains constituents that can potentially inhibit the CYP3A and CYP2D isoenzymes which may in turn lead to pharmacokinetic drug–herb interaction.     

Enhanced Transdermal Peptide Delivery and Stability by Lipid Conjugation: Epidermal Permeation,Stereoselectivity and Mechanistic Insights

Purpose

Efficient delivery of therapeutic peptides to the skin will facilitate better outcomes in dermatology. The tetrapeptide AAPV, an elastase inhibitor with potential utility in the management of psoriasis was coupled to short chain lipoamino acids (Laa: C6-C10) to enhance the peptide permeation into and through human epidermis.

Methods

AAPV was conjugated to Laas by solid phase synthesis. Peptide stability, skin distribution and permeation, elastase activity and surface activity were determined.

Results

Laas increased peptide permeation into the skin. The permeation lag time and amount of peptide remaining in the skin increased with the carbon chain length of the Laa conjugate. We also demonstrated stereoselective permeation enhancement in favour of the D-diastereomer. Importantly, the elastase inhibition activity of the peptide was largely retained after coupling to the Laa conjugates, showing potential therapeutic utility. The Laa-peptide structures were shown to be surface active, suggesting that this surfactant-like activity coupled with enhanced lipophilicity may contribute to their interaction with and permeation through the lipid domains of the stratum corneum.

Conclusions

This study suggests that the Laa conjugation approach may be useful for enhancing the permeation of moderately sized peptide drugs with potential application in the treatment of skin disorders.