Synthesis of hydroxyethyl starch 200/0.5-loaded albumin nanoparticles: biocompatibility and interaction mechanism.

We aimed to synthesize hydroxyethyl starch (HES) 200/0.5-loaded bovine serum albumin nanoparticles (HBNs) and investigate the compatibility and binding mechanism in simulated physiological environments. Here, to elucidate the morphology, biocompatibility, and formation mechanism of HBNs, techniques such as scanning electron microscopy, haemolysis test, fluorescence, and circular dichroism spectroscopy were applied. The thermodynamic parameters at body temperature (ΔS° = -26.7 J·mol-1 ·K-1 , ΔH° = -3.20 × 104 J·mol-1 , and ΔG = -2.35 × 104 J·mol-1 ) showed a 1:1 binding stoichiometry, which was formed by hydrogen bonds and van der Waals interactions. In addition, the conformational analysis showed that the microenvironment of fluorophores was altered with the adaptational protein secondary structural changes. Energy transfer occurred from the fluorophores to HES with a high possibility. All these results provided accurate and complete primary data for demonstrating the interaction mechanisms of HES with BSA, which helps to understand its pharmaceutical effects in blood.

Clinical Value of Total Intravenous Anesthesia with Sufentanil and Propofol in Radical Mastectomy.

Objective: To investigate the clinical value of sufentanil combined with propofol for total intravenous anesthesia (TIVA) in radical mastectomy. Methods: The data of 120 patients undergoing radical mastectomy of breast cancer in our hospital from February 2020 to February 2021 were retrospectively analyzed, and they were randomly assigned to the experimental group (EXG) (n = 60) and the control group (COG) (n = 60). The anesthesia maintenance scheme was 0.01-0.03 µg/(kg·min) of sufentanil + 80-100 µg/(kg·min) of propofol in EXG and 3 µg/(kg·h) of fentanyl + 80-100 µg/(kg·min) of propofol in COG. The hemodynamic indices, stress indexes, postoperative pain scores, and incidence of adverse reactions were compared between EXG and COG. Results: The heart rates (HR) and mean arterial pressure (MAP) after tracheal intubation (T2) and at separation of deep tissues (T3), tracheal extubation (T4), and the end of surgery (T5) were markedly lower in EXG than in COG (P < 0.001). The stress indexes and postoperative pain scores at 1 h (T6), 6 h (T7), and 12 h (T8) after surgery were lower in EXG than in COG (P < 0.001). The incidence of dizziness, headache, pruritus, and emergence agitation in EXG was lower compared with that in COG (P < 0.05). Conclusion: Sufentanil combined with propofol for TIVA can stabilize intraoperative hemodynamic indices of patients undergoing radical mastectomy, alleviate perioperative stress response, and reduce pain perception. Therefore, this anesthesia method is safe and merits clinical promotion.

Double-strand breaks measured along a 160 MeV proton Bragg curve using a novel FIESTA-DNA probe in a cell-free environment.

Proton radiotherapy treatment planning systems use a constant relative biological effectiveness (RBE) = 1.1 to convert proton absorbed dose into biologically equivalent high-energy photon dose. This method ignores linear energy transfer (LET) distributions, and RBE is known to change as a function of LET. Variable RBE approaches have been proposed for proton planning optimization. Experimental validation of models underlying these approaches is a pre-requisite for their clinical implementation. This validation has to probe every level in the evolution of radiation-induced biological damage leading to cell death, starting from DNA double-strand breaks (DSB). Using a novel FIESTA-DNA probe, we measured the probability of double-strand break (P DSB) along a 160 MeV proton Bragg curve at two dose levels (30 and 60 Gy (RBE)) and compared it to measurements in a 6 MV photon beam. A machined setup that held an Advanced Markus parallel plate chamber for proton dose verification alongside the probes was fabricated. Each sample set consisted of five 10 µl probes suspended inside plastic microcapillary tubes. These were irradiated with protons to 30 Gy (RBE) at depths of 5-17.5 cm and 60 Gy (RBE) at depths of 10-17.2 cm with 1 mm resolution around Bragg peak. Sample sets were also irradiated using 6MV photons to 20, 40, 60, and 80 Gy. For the 30 Gy (RBE) measurements, increases in P DSB/Gy were observed at 17.0 cm followed by decreases at larger depth. For the 60 Gy (RBE) measurements, no increase in P DSB/Gy was observed, but there was a decrease after 17.0 cm. Dose-response for P DSB between 30 and 60 Gy (RBE) showed less than doubling of P DSB when dose was doubled. Proton RBE effect from DSB, RBEP,DSB, was <1 except at the Bragg peak. The experiment showed that the novel probe can be used to perform DNA DSB measurements in a proton beam. To establish relevance to clinical environment, further investigation of the probe's chemical scavenging needs to be performed.