Folic acid-modified disulfiram/Zn-IRMOF3 nanoparticles for oral cancer therapy by inhibiting ALDH1A1+ cancer stem cells.

The repurposing of old drugs can reduce the cost of drug development and speed up the availability of drugs for clinical use. Disulfiram (DSF) is an approved drug for alcohol abuse. In recent years, it has been established that DSF exerts an antitumor effect via targeted inhibition of ALDH1+ cancer stem cells (CSCs). However, due to its metal ion dependence, easy hydrolysis and low availability, the clinical application of DSF is limited. Previous studies have also shown that Zn2+ can inhibit CSCs. Accordingly, we developed a novel metal organic framework (IRMOF3)-Zn2+, and DSF was incorporated in the IRMOF3. Folic acid (FA) was subsequently loaded on the surface yielding IRMOF3 (IRMOF3-DSF-FA) for targeted therapy of tumors. The nanoscale IRMOF3-DSF-FA exhibited a high loading capacity, good biocompatibility and strong cell uptake capacity, which could provide metal ions, target tumor tissues and inhibit ALDH1+ CSCs. In vivo experiments showed that IRMOF3-DSF-FA could significantly inhibit the growth of CSCs and tumors, with no significant vital organ damage during treatment. Accordingly, IRMOF3-DSF-FA has great prospects for application as a DSF carrier, opening new horizons for targeted therapy of oral cancer.

Reversible and Highly Ordered Biointerfaces for Efficient Capture and Nondestructive Release of Circulating Tumor Cells.

The engineering strategy of artificial biointerfaces is vital for governing their performances in bioanalysis and diagnosis. Highly ordered arrangement of affinity ligands on the interface surface facilitates efficient interaction with target molecules, whereas biointerfaces aimed at drug delivery or rare cell isolation require sophisticated stimuli-response mechanisms. However, it is still challenging to facilely fabricate biointerfaces possessing the two features. Herein, we endow a biointerface with both reversibility and capability to orderly assemble affinity ligands by introducing boronic acid moieties alone. By boronate conjugation via glycosylation sites, avidin was well arranged at the surface of boronic acid-decorated carbon nitride nanosheets for the assembly of biotinylated aptamers. The ordered orientation of aptamers largely relieved their inactivation caused by inter-strand entanglement, facilitating significant increase in cell affinity for the isolation of circulating tumor cells (CTCs). The reversible boronate conjugation also facilitated mild release of CTCs by acid fructose with high cell viability. This engineered interface was capable of isolating CTCs from the peripheral blood of tumor-bearing mice and cancer patients. The successful utilization of the isolated CTCs in the downstream drug susceptibility test and mutation analysis demonstrated the clinical potential of this biointerface for the early diagnosis of cancers and precision medicine.

Investigation on selenium and mercury interactions and the distribution patterns in mice organs with LA-ICP-MS imaging.

It is the first time to investigate local distribution patterns of mercury (Hg) in mice organs after Hg and Se exposure with detection of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Two batch of adult mice were employed to be exposed to inorganic mercury (iHg) and methylmercury (MeHg) with or without Se at the dose of 55 µmol kg-1. Tissue sections of brain, kidney, liver, and spleen from one batch mice were prepared to get local imaging of Hg by LA-ICP-MS. Tissues from another batch mice were used to quantify Hg and Se in tissues with ICP-MS after acid digestion. The results indicated that, for mice exposed to iHg, Hg mainly distributed in kidney, a little in liver, and hardly in brain and spleen; for mice exposed to MeHg, lower amount of Hg was found in kidney, liver and spleen, and almost no Hg was found in brain. It was interesting that for Hg and Se co-administration groups, higher level of Hg was observed in kidney, liver, spleen and even in brain than single Hg administration groups. In addition, Se level in organ tissues increased obviously not only in Se exposure group but also in MeHg exposure group, while the phenomenon was not observed in iHg exposure group. HepG2 cells were employed to investigate Se and Hg interactions in single cell level, similar bioaccumulation behavior of Hg was found between cells and mice organs. Higher level of Hg was observed in cells cultured with Se and Hg medium than cells cultured with single Hg medium. The results are expected to provide new insight to investigate Hg and Se interactions in animal bodies and in-vitro cells.

Research progress on the application of antibacterial titanium alloys in stomatology / 口腔疾病防治

@#Currently, titanium alloys are widely used in the field of stomatology; however, owing to long-term exposure to a complex microbial environment, dental plaques easily form on the surface of the materials, affecting the use efficiency and the service life of the materials. The antibacterial titanium alloy is a new kind of titanium alloy with antimicrobials added through surface modification or overall modification. Based on the location of antibacterial agents in titanium alloy materials, antibacterial titanium alloys can be divided into coating and alloy types. The antibacterial effect of coated antibacterial titanium alloy is good, but the disadvantage is that most of the coatings are not wear-resistant. The widely-used antibacterial agent of the alloy type is metal elements, which can be evenly distributed in the alloy, and the antibacterial properties are stable and long-lasting. Based on whether antibacterial agents can be released, antibacterial titanium alloys can be further divided into active antibacterial and passive antibacterial types. Active antibacterial type titanium alloys can release loaded antibacterial agents, and the antibacterial effect is more obvious, but the release duration of antibacterial agents is relatively short. Passive antibacterial titanium alloys exhibit an antibacterial effect by contact sterilization or inhibition of bacterial adhesion instead of releasing antibacterial agents. The antibacterial titanium alloy can inhibit the adhesion of bacteria on the surface of the material and prolong the service life of oral orthodontic appliances, implants and titanium plates. Moreover, the mechanical properties of the titanium alloy after antibacterial modification are not significantly affected, and the addition of antibacterial agents such as hydroxyapatite can increase the osteogenic function of the material. Therefore, the alloy has good application prospects in the fields of dental implant, orthodontic treatment and oral and maxillofacial surgery. However, most of the current studies on antibacterial titanium alloys are in vitro experiments, and their long-term clinical effects and antibacterial mechanisms are still unclear and need further study.

Effects of intrathecal isoflurane administration on nociception and Fos expression in the rat spinal cord.

BACKGROUND AND OBJECTIVE: Isoflurane has been used as an inhaled anaesthetic for nearly 30 years. Isoflurane inhalation during anaesthesia also produces an anti-nociceptive effect. Whether this occurs at the spinal or supraspinal level remains unknown. With a novel type of liquid isoflurane, the present study examined the effects of intrathecal isoflurane on the nociceptive response and Fos expression in the rat spinal cord. METHODS: Thirty-six rats were randomly assigned to three groups as follows: group A (n = 6), intrathecal physiological saline 50 µl kg⁻¹; and group B and C (n = 6 each), intrathecal isoflurane at doses of 25 µl kg⁻¹ or 50 µl kg⁻¹, respectively. Noxious thermal (Hargreaves test), mechanical (von Frey test) and chemical (formalin 5%, 50 µl) stimuli were applied to a hind paw after intrathecal isoflurane injection to study its anti-nociceptive effect. In addition, the expression of Fos protein and c-fos mRNA in the spinal dorsal horns was detected by immunohistochemistry and real-time reverse transcriptase PCR, respectively. RESULTS: Compared with the physiological saline control, intrathecal isoflurane significantly suppressed spontaneous paw flinches in rats induced by formalin injection and paw withdrawal induced by thermal and mechanical stimuli in a dose-dependent manner. Immunohistochemistry and real-time reverse transcriptase PCR revealed that isoflurane administration inhibited formalin injection-induced c-fos expression in the spinal cord. CONCLUSIONS: These data suggest that isoflurane can exert anti-nociceptive effects at the spinal level by preventing neuronal activation.

Intravenous administration of hyperoxygenated solution attenuates pulmonary edema formation in phosgene-induced acute lung injury in rabbits.

BACKGROUND: The aim of this study was to investigate the post-treatment effect of intravenous hyperoxygenated solution (HOS) on pulmonary parameters in rabbits whole-body-exposed to the toxic gas phosgene. MATERIALS AND METHODS: Twenty-four New Zealand rabbits were divided into four groups randomly: rabbits were exposed whole-body to either filtered room air or 539 ppm phosgene for 5 minutes followed by room air washout for 5 minutes. Phosgene-exposed group (exposed to phosgene without treatment, PH group); Control group (exposed to air, Control group); Lactate Ringer's solution (LRS)-treated group (intravenous infusion of LRS by 30 ml·kg-1 after phosgene exposure, LRS group); Hyperoxygenated solution (HOS)-treated group (intravenous infusion of HOS after phosgene exposure by 30 mL·kg-1, HOS group). Arterial blood was collected for blood gas analysis at 1, 3, 8, and 12 hours after phosgene or air exposure. Rabbits were put to death 12 hours after exposure. Lung edema was assessed gravimetrically by measuring tissue wet/dry weight ratio (W/D) and lung coefficient (LC). Bronchoalveolar lavage (BAL) was performed and fluid was analyzed for total maloaldehyde (MDA), glutathione peroxidase (GSH-Px), and protein concentration. Lungs were perfused with saline to remove blood, snap-frozen in liquid nitrogen (N2), analyzed for tissue reduced glutathione (GSH) and oxidized glutathione (GSSG). Parts of lung tissues were reserved for histopathology examination. RESULTS: In the PH, LRS, and HOS groups, phosgene inhalation caused serious lung edema, W/D and LC, lung tissue GSSG, BALF MDA, and protein content increased significantly. Meanwhile, PaO2, lung tissue GSH, and BALF GSH-Px decreased markedly. However, after HOS treatment in the HOS group, PaO2 was clearly higher than that in the PH group and LRS group at 3, 8, 12 hours (P < 0.01). W/D and LC, lung tissue GSSG, BALF MDA, and protein content in the HOS group were apparently lower than that in the PH group and LRS group (P < 0.01). In the HOS group, lung tissue GSH and BALF GSH-Px increased compared with both PH and LRS group, respectively. There was no difference on lung tissue GSH among the PH, LRS, and HOS groups (P > 0.05). CONCLUSIONS: Intravenous HOS infusion after phosgene exposure can clearly lessen phosgene-induced lung edema formation, lipid peroxidatic reaction, and ameliorate hypoxemia associated with phosgenismus; it is a safe, simple, and effective measure to protect animals from phosgene-induced lung injury.

[Determination of propofol in human serum by improved reversed phase high-performance liquid chromatography with fluorescence detection].

OBJECTIVE: To develop a new high-performance liquid chromatographic (HLPC) method for determination of propofol in human serum. METHODS: Human serum samples were precipitated with 20% perchloric acid and centrifuged to obtain 50 microl of the supernatant for analysis by HPLC coupled with fluorescence detection. The analysis was performed with a C(18) reversed-phase column using a acetonitrile-water (90:10) phase delivered at 1.0 ml/min, with the excitation wavelength of 276 nm and emission wavelength of 310 nm. RESULTS: The calibration curves were linear (r=0.997 5) within the concentration range of 0.05-10 microg/ml, the limit of propofol quantification was 50 ng/ml and the intra- and inter-day precisions were between -/+15%. CONCLUSIONS: The method is accurate, sensitive and simple for propofol determination in clinical anesthesia.