BACKGROUND:An ideal scaffold material needs appropriate degradation rate and certain mechanical properties, but the traditional colagen sponge scaffold has rapid degradation velocity and low mechanical strength, which is easy to colapse and difficult to maintain its natural form. Traditional cross-linking methods also have the problems of cytotoxicity or colagen denaturation, severely limiting the application of colagen. OBJECTIVE:To design a new cross-linking method for colagen and to optimize the self-assembly process so as to develop a colagen sponge scaffold with good mechanical properties and resistance to degradation. METHODS:Colagens were modified by self-assembly technology to prepare colagen fibrils which were then freeze-dried into fibrilar colagen sponges. Meanwhile, we optimized the conditions of self-assembly by using orthogonal experiment based on univariate analysis of the effect of initial colagen mass concentration, final phosphate concentration and pH value on the conversion yield of colagen self-assembly. RESULTS AND CONCLUSION:We optimized the conditions of self-assembly revealed that the optimum conditions to prepare colagen fibrils were determined as pH=8.0, initial colagen concentration=2 mg/mL, and final concentration of phosphate=15 mmol/L. The results of scanning electron microscope showed that fibrilar colagen sponges were characterized by refined porous structure which was connected by colagen fibrils. In addition, the fibrilar colagen sponges showed better equilibrium-sweling ratio, water retaining property and mechanical strength compared with unmodified colagen spondages (P < 0.05), to solve the problems in rapid degradation.

BACKGROUND:Colagen materials have good biocompatibility and biodegradability, but also had some problems such as low mechanical strength, poor resistance to degradation exposed in the process of clinical application. Numerous studies have reported that proper crosslinking could improve the disadvantage of colagen materials, regulate porous network structure, sweling and degradation of colagen materials. OBJECTIVE: To optimize carbodimide crosslinking process of colagen sponge and determine the best process conditions. METHODS:Colagen sponge was cross-linked by carbodimide for the preparation of loose and porous colagen sponge. Meanwhile, we optimized the conditions of cross-linking, in which the selected concentration of carbodimide was 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 mmol/L, linking time was 2, 4, 6, 8, 12, 16, 20, 24 hours, and linking temperature was 5, 10, 15, 20, 25, 30, 35℃. We evaluated the best process conditions of colagen sponge through the aperture, porosity, water absorption, and degradation rate. RESULTS AND CONCLUSION:The optimal conditions were carbodimide concentration 50 mmol/L, crosslinking temperature 20℃,crosslinking time 6 hours. At this point, the average pore diameter of colagen sponge was 105 μm, the porosity was 79.45%, water absorption was 287.14%, and the degradation rate was 15.04% (2 days). The crosslinking of colagen sponge significantly improved its water absorption and degradation resistance.

To synthesize salbutamol immunogen and develop an enzyme immunoassay (ELISA), a new salbutamol immunogen was synthesized using 4-aminobenzoic acid as a linker to connect hapten with carrier protein. An enzyme immunoassay based on the antibody prepared was developed and applied to detect salbutamol residue spiked in swine liver. An unusual coating antigen, clenbuterol-ovalbumin (OVA) conjugate instead of salbutamol-OVA conjugate, was used in the immunoassay and the results were discussed based on the structures of related compounds. The antibodies showed high sensitivity in the heterologous assay when using clenbuterol-OVA as a coating antigen, with an IC50 value of 8.97 ng mL(-1) toward salbutamol. The antibodies prepared showed high cross-reactivity with clenbuterol (107%) and were promising for the simultaneous determination of salbutamol and clenbuterol residues in food and food products. Recovery rates from the salbutamol-spiked swine liver samples were in the range of 70%-99%, while the intra-assay and inter-assay coefficients of variation were <13.3% and <14.3%, respectively. In summary, the antibodies of salbutamol have been successfully prepared. Sensitive and stable analysis for the detection of salbutamol residues in swine liver was obtained based on the competitive ELISA methods developed in this study.

IL-1有IL-1α和IL-1β两种亚型，其受体家族包括I型和II型两种受体形式（IL1R1和IL1R2）以及一种受体辅助蛋白 （IL1RAP）。在IL1RAP帮助下，IL-1α和IL-1β均可与ILR1形成IL-1/IL1R1/IL1RAP复合物，激活下游信号转导通路，发挥生物学 作用； IL1R2由于缺少胞内TIR结构域无法介导IL-1信号通路，而能通过与IL1R1竞争性结合抑制IL-1的作用。IL1R2起初被认 为是一种IL-1的诱捕受体，但在后续的研究中发现其在多种肿瘤中有异常表达，且多数呈现异常上调状态，仅在少数肿瘤中低表 达，其表达与许多肿瘤的发生发展以及预后有着重要关联。本文针对IL1R2在肿瘤发生发展中的作用方面的相关研究进展进行 综述。

Leptin, an adipocyte-derived peptide hormone, has been shown to facilitate breathing. However, the central sites and circuit mechanisms underlying the respiratory effects of leptin remain incompletely understood. The present study aimed to address whether neurons expressing leptin receptor b (LepRb) in the nucleus tractus solitarii (NTS) contribute to respiratory control. Both chemogenetic and optogenetic stimulation of LepRb-expressing NTS (NTS^LepRb) neurons notably activated breathing. Moreover, stimulation of NTS^LepRb neurons projecting to the lateral parabrachial nucleus (LPBN) not only remarkably increased basal ventilation to a level similar to that of the stimulation of all NTS^LepRb neurons, but also activated LPBN neurons projecting to the preBötzinger complex (preBötC). By contrast, ablation of NTS^LepRb neurons projecting to the LPBN notably eliminated the enhanced respiratory effect induced by NTS^LepRb neuron stimulation. In brainstem slices, bath application of leptin rapidly depolarized the membrane potential, increased the spontaneous firing rate, and accelerated the Ca²⁺ transients in most NTS^LepRb neurons. Therefore, leptin potentiates breathing in the NTS most likely via an NTS-LPBN-preBötC circuit.
Leptin/pharmacology* ; Membrane Potentials ; Neurons/metabolism* ; Solitary Nucleus/metabolism*