Deciphering Reaction Products in Formamidine-Based Perovskites with Methylammonium Chloride Additive.

The fabrication of formamidinium lead iodide (FAPbI3) perovskite solar cells (PSCs) involves the addition of methylammonium chloride (MACl) to promote low-temperature α-phase formation and grain growth. However, as the added MACl deprotonates and volatilizes into methylamine (MA0) and HCl for removal, MA0 can chemically interact with formamidinium (FA+), forming methyl formamidinium (MFA+) as a byproduct. Despite its significance, the chemical interactions among FAPbI3 perovskites, MACl additives, and their byproducts remain poorly understood. Our findings reveal that the FA+ and MA0 reaction primarily yields a mixture of cis/trans-N-methyl formamidinium iodide (MFAI) isomers, with cis-MFAI prevailing as the dominant species. Moreover, MFAI subsequently reacts with PbI2 to yield fully formed cis-MFAPbI3 2H-phase perovskite. We elucidated the effects of MFAI on the crystal growth, phase stability, and band gap of formamidine-based perovskites through the growth of single crystals. This research offers valuable insights into the role of these byproducts in influencing the efficiency and long-term stability of future PSCs.

Production of a 135-residue long N-truncated human keratinocyte growth factor 1 in Escherichia coli.

BACKGROUND: Palifermin (trade name Kepivance®) is an amino-terminally truncated recombinant human keratinocyte growth factor 1 (KGF-1) with 140 residues that has been produced using Escherichia coli to prevent and treat oral mucositis following radiation or chemotherapy. In this study, an amino-terminally shortened KGF-1 variant with 135 residues was produced and purified in E. coli, and its cell proliferation activity was evaluated. RESULTS: We expressed soluble KGF-1 fused to thioredoxin (TRX) in the cytoplasmic fraction of E. coli to improve its production yield. However, three N-truncated forms (KGF-1 with 140, 138, and 135 residues) were observed after the removal of the TRX protein from the fusion form by cleavage of the human enterokinase light chain C112S (hEKL C112S). The shortest KGF-1 variant, with 135 residues, was expressed by fusion with TRX via the hEKL cleavage site in E. coli and purified at high purity (> 99%). Circular dichroism spectroscopy shows that purified KGF-1135 had a structure similar to that of the KGF-1140 as a random coiled form, and MCF-7 cell proliferation assays demonstrate its biological activity. CONCLUSIONS: We identified variations in N-terminus-truncated KGF-1 and selected the most stable form. Furthermore, by a simple two-step purification, highly purified KGF-1135 was obtained that showed biological activity. These results demonstrate that KGF-1135 may be considered an alternative protein to KGF-1.

High-level production of keratinocyte growth factor 2 in Escherichia coli.

Recombinant human keratinocyte growth factor 2 (KGF-2), also known as repifermin, is used in various therapeutic applications. However, KGF-2 production has not been optimized for facilitating large-scale production. Therefore, we attempted to attain high-level production of bioactive KGF-2. KGF-2 was fused with 6HFh8 (6HFh8-KGF-2) at the tobacco etch virus protease cleavage site. The 6HFh8-KGF-2 was expressed in Escherichia coli with high expression levels of approximately 33% and 20% of soluble protein in flask culture and 5 L fermentation, respectively. 6HFh8-KGF-2 was purified via nickel affinity chromatography. To maintain a stable form of KGF-2, the conditions of the cleavage reaction were optimized based on the isoelectric point. KGF-2 was purified via ion-exchange chromatography to high purity (>99%) with an optimal purification yield (91%). Circular dichroism spectroscopy demonstrated that purified KGF-2 had a secondary structure and thermal stability similar to that of commercial KGF-2. Bioactivity assays indicated that purified KGF-2 could induce MCF-7 cell proliferation in the same manner as commercial KGF-2. These results demonstrate that bioactive KGF-2 was overexpressed in E. coli and purified to high quality. Our findings indicated that bioactive KGF-2 can be produced in large quantities in E. coli.

Genomic Profiling of Aggressive Thyroid Cancer in Association With its Clinicopathological Characteristics.

BACKGROUND/AIM: Poorly differentiated thyroid carcinoma (PDTC), anaplastic thyroid carcinoma (ATC), and advanced DTC have poor outcomes. MATERIALS AND METHODS: We performed next-generation sequencing in nine selected aggressive thyroid cancers. RESULTS: Among the nine patients, the driver gene mutations BRAF V600E (3/9) and NRAS Q61K (1/9) were detected. Other oncogenic mutations included ERBB2 (1/9) and CDK4 (1/9). Telomerase reverse transcriptase (TERT) promoter mutation was found in five cases. Among tumor suppressor genes, mutations in TP53 (3/9), ARID1A (1/9), APC (1/9), MEN1 (1/9), DICER1 (1/9), and MED12 (1/9) were identified. RET fusions were found in two cases, one with PTDC and the other with ATC. The ATC with RET fusion also harbored TP53 and TERT promoter mutations. None of the PDTC cases had BRAF or RAS gene alterations. CONCLUSION: Since genetic alterations with therapeutic and prognostic implications were detected using next-generation sequencing, this technique is recommended to be performed for patients with aggressive thyroid cancer.

Short-Term Outcomes of Switching to Ranibizumab in Polypoidal Choroidal Vasculopathy Resistant to Aflibercept Therapy.

BACKGROUND: To evaluate the short-term outcomes of switching to ranibizumab in aflibercept-resistant polypoidal choroidal vasculopathy (PCV). METHODS: This retrospective study included 18 eyes diagnosed with aflibercept-resistant PCV. All patients were treated with two to four consecutive ranibizumab injections at 4-5-week intervals. The best-corrected visual acuity (BCVA), and central retinal thickness (CRT) values before and after switching to ranibizumab were compared. The proportion of eyes showing ≥100 µm decrease in retinal thickness and/or complete resolution of fluid after switching was identified. RESULTS: The mean number of aflibercept injections before switching was 5.7 ± 3.3. After switching, a mean of 2.8 ± 0.6 consecutive ranibizumab injections was performed. The mean logarithm of minimal angle of resolution (logMAR) BCVA was 0.41 ± 0.26 (Snellen equivalents = 20/51) before switching, and 0.40 ± 0.30 (20/50) after switching (p = 0.574). The mean CRT was 422.2 ± 152.4 µm before switching, and 400.7 ± 182.0 µm after switching (p = 0.236). A decrease in CRT of ≥100 µm, and/or complete resolution of fluid was noted in three eyes (16.7%). CONCLUSIONS: Switching to ranibizumab in aflibercept-resistant polypoidal choroidal vasculopathy was not effective in most patients, suggesting the need for further investigation to seek more effective treatment options for this condition.

Investigation of the Trend of Selecting Anti-Vascular Endothelial Growth Factor Agents for the Initial Treatment of Neovascular Age-Related Macular Degeneration and Polypoidal Choroidal Vasculopathy.

BACKGROUND: This study aimed to investigate the trend of selecting ranibizumab and aflibercept for the initial treatment of neovascular age-related macular degeneration (AMD) and polypoidal choroidal vasculopathy (PCV). METHODS: This was a retrospective study that included 460 patients who were diagnosed with treatment-naïve neovascular AMD and PCV and were initially treated with either ranibizumab or aflibercept. The patients were divided into two groups: the ranibizumab group (n = 96) and the aflibercept group (n = 324). The patients' characteristics and the proportion of the subtypes of macular neovascularization (MNV) were compared between the two groups. RESULTS: Patients in the ranibizumab group were significantly older (mean 74.3 ± 8.4 years) than those in the aflibercept group (mean 70.4 ± 8.8 years; p < 0.001). In the ranibizumab group, the proportions of type 1 or 2 MNV, type 3 MNV, and PCV were 50.0%, 27.1%, and 22.9%, respectively. In the aflibercept group, the proportions were 35.2%, 6.8%, and 58.0%, respectively. There was a significant difference in the proportion of MNV subtypes between the ranibizumab and aflibercept groups (p < 0.001). Ranibizumab was used in 54.2% of patients with type 3 MNVs. However, in patients with PCV, aflibercept was used in 89.5% of patients. CONCLUSIONS: Ranibizumab was preferred as an initial treatment agent in older patients and those with type 3 MNV, whereas aflibercept was highly preferred in patients with PCV. The different characteristics and efficacy of the two agents may have partially contributed to this trend.