Poly(L-histidine)-tagged 5-aminolevulinic acid prodrugs: new photosensitizing precursors of protoporphyrin IX for photodynamic colon cancer therapy

Renjith P Johnson,1* Chung-Wook Chung,2* Young-Il Jeong,2 Dae Hwan Kang,2 Hongsuk Suh,3 Il Kim,11WCU Centre for Synthetic Polymer Bioconjugate Hybrid Materials, Department of Polymer Science and Engineering, Pusan National University, Pusan, 2National Research and Development Center for Hepatobiliary Cancer, Pusan National University, Yangsan Hospital, Yangsan, Gyeongnam, 3Department of Chemistry and Chemistry Institute for Functional Materials, Pusan National University, Pusan, Korea*These authors contributed equally to this workBackground: 5-Aminolevulinic acid (ALA) and its derivatives have been widely used in photodynamic therapy. The main drawback associated with ALA-based photodynamic therapy (ALA-PDT) and ALA fluorescence diagnosis results from the hydrophilic nature of ALA and lack of selectivity for tumor versus nontumor cells. The application of certain triggers, such as pH, into conventional sensitizers for controllable 1O2 release is a promising strategy for tumor-targeted treatment.Methods: A series of pH-sensitive ALA-poly(L-histidine) [p(L-His)n] prodrugs were synthesized via ring opening polymerization of 1-benzyl-N-carboxy-L-histidine anhydride initiated by the amine hydrochloride group of ALA itself. As an alternative to ALA for PDT, the synthesized prodrugs were used to treat a cultured human colon cancer HCT116 cell line under different pH conditions. The effect of ALA-p(L-His)n derivatives was evaluated by monitoring the fluorescence intensity of protoporphyrin IX, and measuring the cell survival rate after suitable light irradiation.Results: The cytotoxicity and dark toxicity of ALA and synthesized ALA-p(L-His) derivatives in HEK293T and HCT116 cells in the absence of light at pH 7.4 and 6.8 shows that the cell viability was relatively higher than 100%. ALA-p(L-His)n showed high phototoxicity and selectivity in different pH conditions compared with ALA alone. Because the length of the histidine chain increases in the ALA-p(L-His)n prodrugs, the PDT effect was found to be more powerful. In particular, high phototoxicity was observed when the cells were treated with ALA-p(L-His)15, compared with treatment using ALA alone.Conclusion: The newly synthesized ALA-p(L-His)n derivatives are an effective alternative to ALA for enhancing protoporphyrin IX production and the selectivity of the phototoxic effect in tumor cells.Keywords: 5-aminolevulinic acid, photodynamic therapy, poly(L-histidine), bioconjugate, cancer cell

(1,2-Dicarba-closo-dodeca­boran­yl)trimethyl­methanaminium iodide

The title compound, [1-(CH3)3NCH2-1,2-C2B10H11]+·I− or C6H22B10N+·I−, was obtained by the reaction of (1,2-dicarba-closo-dodeca­boran­yl)dimethyl­methanamine with methyl iodide. The asymmetric unit contains two iodide anions and two (o-carboran­yl)tetra­methyl­ammonium cations. The bond lengths and angles in the carborane cage are within normal ranges, but the N—Cmethyl­ene—Ccage angle is very large [120.2 (2)°] because of repulsion between the carborane and tetra­methyl­ammonium units. In the crystal, ions are linked through C—H⋯I hydrogen bonds

Gypsum-Dependent Effect of NaCl on Strength Enhancement of CaO-Activated Slag Binders

This study explores the combined effect of NaCl and gypsum on the strength of the CaO-activated ground-granulated blast furnace slag (GGBFS) binder system. In the CaO-activated GGBFS system, the incorporation of NaCl without gypsum did not improve the strength of the system. However, with the presence of gypsum, the use of NaCl yielded significantly greater strength than the use of either gypsum or NaCl alone. The presence of NaCl largely increases the solubility of gypsum in a solution, leading to a higher concentration of sulfate ions, which is essential for generating more and faster formations of ettringite in a fresh mixture of paste. The significant strength enhancement of gypsum was likely due to the accelerated and increased formation of ettringite, accompanied by more efficient filling of pores in the system

Comparison of a drug-eluting balloon first and then bare metal stent with a drug-eluting stent for treatment of de novo lesions: study protocol of a randomized controlled trial

Background : The use of a drug-eluting balloon for the treatment of de novo coronary artery lesions remains to be evaluated. A previous trial in patients with stable and unstable angina comparing a bare metal stent mounted on a drug-eluting balloon with a sirolimus-eluting stent failed to meet the prespecified non-inferiority criteria versus the sirolimus-eluting stent. The stent struts of a bare metal stent pre-mounted on a drug-eluting balloon may prevent the appropriate delivery of drugs to the vessel wall and may result in reduced efficacy. In the present study we will therefore evaluate the efficacy of a drug-eluting balloon for treating de novo coronary artery lesions using a strategy designed to uniformly deliver drug to the vessel with a bare metal stent. Methods/Design : The Comparison of Drug-Eluting Balloon first study is a prospective, randomized, open-label trial designed to demonstrate the non-inferiority of first using a drug-eluting balloon (Sequent® please; B. Braun, Melsungen, Germany) followed by a bare metal stent (Coroflex® Blue; B. Braun) compared with using a drug-eluting stent (Resolute Integrity™; Boston Scientific, Natick, MA, USA) for de novo coronary artery lesions. The primary endpoint of the study is in-segment late loss at 9 months measured by quantitative coronary angiography. Secondary endpoints include angiographic findings such as angiographic success, device success, binary angiographic restenosis, and clinical outcomes such as procedural success, all-cause death, myocardial infarction, target vessel revascularization, target lesion revascularization, and stent thrombosis. A total of 180 patients will be enrolled in the study. Discussion : The Comparison of Drug-Eluting Balloon first study will evaluate the clinical efficacy, angiographic outcomes and safety of a drug-eluting balloon first followed by a bare metal stent compared with a drug-eluting stent for the treatment of de novo coronary artery lesions.Peer Reviewe

A Case of Near Total Aortic Replacement in an Adolescent With Loeys-Dietz Syndrome

Loeys-Dietz syndrome is a recently described autosomal dominant disorder caused by mutations in the genes for transforming growth factor-beta receptor type 1 or 2 (TGF-ßR 1/2). The syndrome predisposes patients to aortic aneurysm and dissections, along with craniofacial and musculoskeletal abnormalities. Here we report the case of an adolescent who underwent serial near total aortic replacement, from the aortic valve to the descending aorta. Loeys-Dietz syndrome was confirmed in this case by the detection of a mutation in the TGF-ßR 2 gene

Determination of EGFR Endocytosis Kinetic by Auto-Regulatory Association of PLD1 with mu 2

Background: Upon ligand binding, cell surface signaling receptors are internalized through a process tightly regulated by endocytic proteins and adaptor protein 2 (AP2) to orchestrate them. Although the molecular identities and roles of endocytic proteins are becoming clearer, it is still unclear what determines the receptor endocytosis kinetics which is mainly regulated by the accumulation of endocytic apparatus to the activated receptors. Methodology/Principal Findings: Here we employed the kinetic analysis of endocytosis and adaptor recruitment to show that ??2, a subunit of AP2 interacts directly with phospholipase D (PLD)1, a receptor-associated signaling protein and this facilitates the membrane recruitment of AP2 and the endocytosis of epidermal growth factor receptor (EGFR). We also demonstrate that the PLD1-??2 interaction requires the binding of PLD1 with phosphatidic acid, its own product. Conclusions/Significance: These results suggest that the temporal regulation of EGFR endocytosis is achieved by auto-regulatory PLD1 which senses the receptor activation and triggers the translocation of AP2 near to the activated receptor.open3

Characteristics of pediatric rhabdomyolysis and the associated risk factors for acute kidney injury: a retrospective multicenter study in Korea

Background The clinical features of pediatric rhabdomyolysis differ from those of the adults with rhabdomyolysis; however, multicenter studies are lacking. This study aimed to investigate the characteristics of pediatric rhabdomyolysis and reveal the risk factors for acute kidney injury (AKI) in such cases. Methods This retrospective study analyzed the medical records of children and adolescents diagnosed with rhabdomyolysis at 23 hospitals in South Korea between January 2007 and December 2016. Results Among 880 patients, those aged 3 to 5 years old composed the largest subgroup (19.4%), and all age subgroups were predominantly male. The incidence of AKI was 11.3%. Neurological disorders (53.6%) and infection (39.0%) were the most common underlying disorder and cause of rhabdomyolysis, respectively. The median age at diagnosis in the AKI subgroup was older than that in the non-AKI subgroup (12.2 years vs. 8.0 years). There were no significant differences in body mass index, myalgia, dark-colored urine, or the number of causal factors between the two AKI-status subgroups. The multivariate logistic regression model indicated that the following factors were independently associated with AKI: multiorgan failure, presence of an underlying disorder, strong positive urine occult blood, increased aspartate aminotransferase and uric acid levels, and reduced calcium levels. Conclusions Our study revealed characteristic clinical and laboratory features of rhabdomyolysis in a Korean pediatric population and highlighted the risk factors for AKI in these cases. Our findings will contribute to a greater understanding of pediatric rhabdomyolysis and may enable early intervention against rhabdomyolysis-induced AKI