Analysis of the effect of cations on protein conformational stability using solid-state nanopores.

The conformation of proteins is closely related to their biological functions, and it is affected by many factors, including the type of cations in solution. However, it is difficult to detect the conformational changes of a protein in situ. As a single-molecule sensing technology, nanopores can convert molecular structural information into analyzable current signals within a reasonable time range. Herein, we detect and analyze the effects of two different types of monovalent cations (Na+ and Li+) on a model protein bovine serum albumin (BSA) conformation using SiNx nanopores with different diameters. The quantitative analysis results show that the excluded volume of BSA in LiCl salt solutions is larger than the value in NaCl solution, indicating that Li+ is more prone to unfolding the proteins and making them unstable. This study demonstrated that nanopores enable the in situ detection of the structure of proteins at the single-molecule level and provide a new approach for the quantitative analysis of proteins.

A multicenter phase II trial of primary prophylactic PEG-rhG-CSF in pediatric patients with solid tumors and non-Hodgkin lymphoma after chemotherapy: An interim analysis.

BACKGROUND: Pegylated recombinant human granulocyte colony-stimulating factor (PEG-rhG-CSF) can be used in pediatric patients. This study assessed the safety and efficacy of PEG-rhG-CSF as a primary prophylactic drug against neutropenia after chemotherapy in pediatric patients with solid tumors or non-Hodgkin lymphoma (NHL). PATIENTS AND METHODS: This phase II study (between October 2020 and March 2022) enrolled pediatric patients with solid tumors or NHL treated with high-intensity chemotherapy and with grade ≥3 myelosuppression for at least 14 days during chemotherapy. Prophylactic PEG-rhG-CSF was given at 100 µg/kg body weight (maximum total dosage of 6 mg) once 24-48 h following chemotherapy for two cycles. The primary endpoint was the incidence of PEG-rhG-CSF-related adverse events (AEs). The key secondary endpoints were the rates of grade 3/4 neutropenia and febrile neutropenia (FN). RESULTS: This study included 160 pediatric patients with a median age of 6.22 (0.29, 18.00) years. Fifty-eight patients (36.25%) were diagnosed with sarcoma. AEs potentially related to PEG-rhG-CSF included bone pain (n = 32), fatigue (n = 21), pain at the injection site (n = 21), and myalgia (n = 20). The rates of grade 3/4 neutropenia and FN during treatment were 57.28% and 29.45%, respectively. CONCLUSION: PEG-rhG-CSF is well tolerated and effective in pediatric patients with solid tumors or NHL. These findings should be substantiated with further trials. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT04547829.

Skin-safe nanophotosensitizers with highly-controlled synthesized polydopamine shell for synergetic chemo-photodynamic therapy.

Although photodynamic therapy (PDT) has been extensively studied as an established modality of cancer treatment, it still suffers from a few clinical limitations, such as skin phototoxicity and tumor hypoxia. To circumvent these hurdles, hollow silica mesoporous nanoparticles (HMSNs) loaded with photosensitizers were employed as the nanoplatform to construct multifunctional nanoparticles (NPs). Specifically, an ultra-uniform polydopamine (PDA) shell was highly controlled grown around HMSNs by photogenerated outwards-diffused 1O2, followed by conjugation of folic acid-poly(ethylene glycol) and chelation of Fe2+ ions. Thanks to the optimal thickness of light-absorbing PDA shell, the multifunctional NPs exhibited not only negligible skin phototoxicity but also efficient 1O2 generation and photothermal (PT)-enhanced •OH generation upon respective photoirradiation. Anti-tumor therapy was then performed on both 4 T1 tumor cells and tumor-bearing mice by the combination of 638 nm PDT and 808 nm PT-enhanced chemodynamic therapy (CDT). As a result, high therapeutic efficacy was achieved compared to single-modality therapy, with a cell inhibitory rate of 86% and tumor growth inhibition of 70.4% respectively. More interestingly, tumor metastasis was effectively inhibited by the synergetic treatment. These results convincingly demonstrate that our multifunctional NPs are very promising skin-safe PDT agents combined with CDT for efficient tumor therapy.

Irinotecan Plus Doxorubicin Hydrochloride Liposomes for Relapsed or Refractory Wilms Tumor.

PURPOSE: The prognosis of relapsed or refractory pediatric Wilms tumor (WT) is dismal, and new salvage therapies are needed. This study aimed to evaluate the efficacy of the combination of irinotecan and a doxorubicin hydrochloride liposome regimen for relapsed or refractory pediatric WT. PATIENTS AND METHODS: The present study enrolled relapsed or refractory pediatric WT patients who were treated with the AI regimen (doxorubicin hydrochloride liposomes 40 mg/m2 per day, day 1, and irinotecan 50 mg/m2 per day with 90-min infusion, days 1-5; this regimen was repeated every 3 weeks) at Sun Yat-sen University Cancer Center from July 2018 to September 2020. The response was defined as the best-observed response after at least two cycles according to the Response Evaluation Criteria of Solid Tumors (RECIST 1.1), and toxicity was evaluated according to the Common Terminology Criteria for Adverse Events (CTCAE 4.03). RESULTS: A total of 16 patients (male:female, 8:8) with a median age of 4.2 years (0.5-11 years) with relapsed or refractory disease were enrolled in this study, including 14 patients with relapsed disease and two patients with refractory disease. These patients received 1-8 courses (median, 3 courses) of the AI regimen. Fourteen patients were assessable for response: two with complete response (CR), five with partial response (PR), two with stable disease (SD), and five with progressive disease (PD). The objective response rate was 50% (two CR, five PR), and the disease control rate was 64% (two CR, five PR, and two SD). Seven out of 14 patients (50%) were alive at the last follow-up, ranging from 2.6 to 32.4 months. The median progression-free survival and median overall survival were 3.5 months (range 0.5-12 months) and 8 months (range 1-28 months), respectively. Sixteen patients were assessable for toxicity, with the most common grade 3 or 4 adverse events being alopecia (62%), leukopenia (40%), abdominal pain (38%), diarrhea (23%), and mucositis (16%), etc. No fatal adverse events have been observed, and modest adverse effects can be administered. CONCLUSION: Irinotecan and doxorubicin hydrochloride liposome regimens have positive efficacy on relapsed or refractory pediatric WT with well-tolerated toxicity. A prospective clinical trial is warranted.

A Comprehensive Study of Drug Loading in Hollow Mesoporous Silica Nanoparticles: Impacting Factors and Loading Efficiency.

Although hollow mesoporous silica nanoparticles (HMSNs) have been intensively studied as nanocarriers, selecting the right HMSNs for specific drugs still remains challenging due to the enormous diversity in so far reported HMSNs and drugs. To this end, we herein made a comprehensive study on drug loading in HMSNs from the viewpoint of impacting factors and loading efficiency. Specifically, two types of HMSNs with negative and positive zeta potential were delicately constructed, and three categories of drugs were selected as delivery targets: highly hydrophobic and lipophobic (oily), hydrophobic, and hydrophilic. The results indicated that (i) oily drugs could be efficiently loaded into both of the two HMSNs, (ii) HMSNs were not good carriers for hydrophobic drugs, especially for planar drugs, (iii) HMSNs had high loading efficiency towards oppositely charged hydrophilic drugs, i.e., negatively charged HMSNs for cationic molecules and vice versa, (iv) entrapped drugs would alter zeta potential of drug-loaded HMSNs. This work may provide general guidelines about designing high-payload HMSNs by reference to the physicochemical property of drugs.

Luminescent ruthenium(II)-containing metallopolymers with different ligands: synthesis and application as oxygen nanosensor for hypoxia imaging.

A series of Ru(II)-containing metallopolymers with different polypyridyl complexes, namely [Ru(N^N)2(L)](PF6)2 (L = bipyridine-branched polymer; N^N = bpy: 2,2'-bipyridine (Ru 1); phen: 1,10-phenanthroline (Ru 2); dpp: 4,7-diphenyl-1,10-phenanthroline (Ru 3)), were synthesized with the motive that adjusting π-conjugation length of ligands might produce competent luminescent oxygen probes. The three hydrophobic metallopolymers were studied with 1H NMR, UV-Vis absorption, and emission spectroscopy, and then were utilized to prepare biocompatible nanoparticles (NPs) via a nanoprecipitation method. Luminescent properties of the NPs were investigated against dissolved oxygen by steady-state and time-resolved spectroscopy respectively. Luminescence quenching of the three NPs all followed a linear behavior in the range of 0-43 ppm (oxygen concentration), but Ru 3-NPs exhibited the highest oxygen sensitivity (82%) and longest emission wavelength (λex = 460 nm; λem = 617 nm). In addition, external interferons from cellular environments (e.g., pH, temperature, and proteins) had been studied on Ru 3-NPs. Finally, dissolved oxygen in monolayer cells under normoxic/hypoxic conditions was clearly differentiated by using Ru 3-NPs as the luminescent sensor, and, more importantly, hypoxia within multicellular tumor spheroids was vividly imaged. These results suggest that such Ru(II)-containing metallopolymers are strong candidates for luminescent nanosensors towards hypoxia. Graphical abstract.

[Clinical and variant analysis of 15 patients with methylmalonic acidemia].

OBJECTIVE: To report on clinical characteristics and genetic findings in 15 Chinese patients with methylmalonic acidemia (MMA). METHODS: For the 15 MMA patients detected by tandem mass spectrometry, genetic analysis was carried out in twelve pedigrees. Clinical characteristics, genetic finding, treatment and outcomes were retrospectively analyzed. RESULTS: The main features of the patients included poor feeding, recurrent vomiting, lethargy, seizure and development retardation. Blood propionylcarnitine (except for 3 patients), its ratio with acetylcarnitine, and urine methylmalonic acid were increased in all patients. Twelve patients were diagnosed genetically, which included 7 with MUT variants, 4 with MMACHC variants, and 1 with MMAB variant. Nine MUT variants were detected, among which c.1159A>C, 753+1delGinsTGGTTATTA and c.504del were novel. Six known pathogenic MMACHC variants and two novel MMAB variants (c.289_290delGG, c.566G>A) were also detected. Seven patients died of metabolic crises within a year, others had improved effectively following the treatment, but had mild to severe growth delay and/or developmental retardation. CONCLUSION: The clinical manifestation of MMA are complex. Most patients have variants of the MUT and MMACHC genes. High mortality may occur before one year of age.

Sensitive detection of PDT-induced cell damages with luminescent oxygen nanosensors.

In this work luminescent nanosensors specifically created for intracellular oxygen (ic-O2) were utilized to assess photodynamic therapy (PDT) -induced cell damages. Firstly, ic-O2 was demonstrated to be consumed much faster than extracellular O2 with respective O2 nanosensors. Using the ic-O2 nanosensors, PDT-treated cells with different degree of impairment were then resolved according to the oxygen consumption rate (OCR). The evolving trend of cytotoxicity derived from OCRs was in agreement with cell viability obtained from 3-(4,5-cimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Moreover, the direct damage of PDT on cell mitochondria was successfully detected by monitoring respiration instantly after PDT treatment, which is actually beyond the scope of MTT assay. These results suggest that fluorescence sensing of ic-O2-associated cell respiration is promising and even may become a standardized method, complementary to MTT assay, to evaluate PDT-induced cytotoxicity.

Chronic intermittent hypobaric hypoxia prevents cardiac dysfunction through enhancing antioxidation in fructose-fed rats.

High-fructose intake induces metabolic syndrome and cardiac dysfunction. Chronic intermittent hypobaric hypoxia (CIHH) preserves cardiac function during ischemia. We hypothesized that CIHH restores the impaired cardiac function in fructose-fed rats. Sprague-Dawley rats were randomly subject to treatment with fructose (10% fructose in drinking water for 6 weeks), CIHH (simulated 5000 m altitude, 6 h/day for 6 weeks in a hypobaric chamber), and CIHH plus fructose groups. In addition to an increase in blood pressure, fructose feeding caused elevated serum levels of glucose, fasting insulin and insulin C peptide, triglyceride, cholesterol, and mass ratio of heart to body. CIHH treatment decreased the arterial blood pressure, serum levels of biochemical markers, and cardiac hypertrophy in fructose-fed rats. Furthermore, CIHH treatment improved the recovery of left ventricular function after ischemia-reperfusion procedure (30 min global no-flow ischemia followed by 60 min of reperfusion) in rats with or without fructose feeding. In addition, CIHH treatment caused a significant increase in superoxide dismutase (SOD) activity and decrease in malondialdehyde level in cardiac myocardium experiencing ischemia-reperfusion in control and fructose-fed rats. Collectively, these data suggest that CIHH improve impaired cardiac function in fructose-fed rats through enhancing antioxidation in the myocardium.

[Determination of the fluorine release of fluoride varnishes by neutron activation method].

OBJECTIVE: To determine the fluorine content in enamel before and after besmearing fluoride varnishes by neutron activation method. METHODS: A pair of mandibular deciduous central incisor teeth were chosen. One was removed, and the other was besmeared with fluoride varnishes and removed 24 hours later. The contents of fluorine were determined and analyzed statistically. RESULTS: The fluorine content in the enamel of the tooth besmeared with fluoride varnishes was higher than that in the control tooth (P < 0.05). CONCLUSIONS: The application of the fluoride varnishes can effectively increase the content of fluorine in the sclerous tissues.