Detection method of nonlinear magnetized harmonic signal of medical magnetic nanoparticles / 生物医学工程学杂志

Medical magnetic nanoparticles are nano-medical materials with superparamagnetism, which can be collected in the tumor tissue through blood circulation, and magnetic particle imaging technology can be used to visualize the concentration of magnetic nanoparticles in the living body to achieve the purpose of tumor imaging. Based on the nonlinear magnetization characteristics of magnetic particles and the frequency characteristics of their magnetization, a differential detection method for the third harmonic of magnetic particle detection signals is proposed. It was modeled and analyzed, to study the nonlinear magnetization response characteristics of magnetic particles under alternating field, and the spectral characteristics of magnetic particle signals. At the same time, the relationship between each harmonic and the amount of medical magnetic nanoparticle samples was studied. On this basis, a signal detection experimental system was built to analyze the spectral characteristics and power spectral density of the detected signal, and to study the relationship between the signal and the excitation frequency. The signal detection experiment was carried out by the above method. The experimental results showed that under the alternating excitation field, the medical magnetic nanoparticles would generate a spike signal higher than the background sensing signal, and the magnetic particle signal existed in the odd harmonics of the detected signal spectrum. And the spectral energy was concentrated at the third harmonic, that is, the third harmonic magnetic particle signal detection that meets the medical detection requirement could be realized. In addition, the relationship between each harmonic and the particle sample volume had a positive growth relationship, and the detected medical magnetic nanoparticle sample volume could be determined according to the relationship. At the same time, the selection of the excitation frequency was limited by the sensitivity of the system, and the detection peak of the third harmonic of the detection signal was reached at the excitation frequency of 1 kHz. It provides theoretical and technical support for the detection of medical magnetic nanoparticle imaging signals in magnetic particle imaging research.

The effects of rhPDGF-BB combined with rhTGF-β1 on FAK mRNA expression of osteoclasts in the alveo-lar bone on the pressure side of orthodontic teeth in rats / 实用口腔医学杂志

Objective:To study the effects of recombinant human platelet-derived growth factor-BB(rhPDGF-BB)combined with recombinant human transforming growth factor-β1 (rhTGF-β1 )on the expression of FAK mRNA of osteoclasts in the alveolar bone on the pressure side of orthodontic teeth in rats.Methods:Orthodontic tooth movement model was established in 160 male SD rats.The rats in experimental group were treated by injection of 10 ng rhPDGF-BB and 5 ng rhTGF-β1 in the buccal submucosal area of the mo-lar every other day from day 1 afterburner,while those in control group received equivalent volumes of PBS.The rats were sacrificed at 1,4,7,10 and 14 days(n=16)after appliance placement.Specimens were collected.Osteoclasts in the alveolar bone on the pres-sure side of the orthodontic teeth were observed by TRAP staining,the FAK mRNA expression was quantified by quantitative RT-PCR.Results:rhPDGF-BB combined with rhTGF-β1 significantly promoted an increasing number of osteoclasts on the compressing side(P0.05) at day 14.Conclusion:Combination of rhPDGF-BB and rhTGF-β1 can increase the number of osteoclasts in the alveolar bone on compressing side,and promote FAK mRNA expression in osteoclasts.

Effect of tea polyphenols on proliferation of human periodontal ligament fibroblasts / 南方医科大学学报

<p><b>OBJECTIVE</b>To determine the effect of tea polyphenol (TP) on the proliferation of human periodontal ligament fibroblasts (HPDLFs).</p><p><b>METHODS</b>HPDLFs were primary cultured from tissue explants, and the cells of the 5th to 8th passages were used after immunohistochemical identification (with SABC method) of keratin and vimentin expressions. The cells were divided into 5 groups and treated with TP at 1, 0.5, 0.25, 0.125, and 0.0625 mg/ml, respectively, with another group without TP treatment as the blank control group. Cell counting and MTT colorimetric assay were performed to assess the cell proliferation, and flow cytometry was employed to determine the DNA content of the HPDLFs.</p><p><b>RESULTS</b>Different concentrations of TP all significantly increased the proliferation and DNA synthesis of the HPDLFs (P<0.05), and TP treatment at 0.5 mg/ml for 6 h produced the optimal effect.</p><p><b>CONCLUSION</b>TP has obviously effect in promoting the proliferation of HPDLFs.</p>

Effects of two metabolites of cultured marine fungus, Halorosellinia oceanicum 323, on the contraction of isolated guinea-pig ileum / 药学学报

<p><b>AIM</b>To investigate the effects of 323-A and 323-B, two isomers extracted from the metabolites of cultured marine fungus, Halorosellinia oceanicum 323, on the contraction of isolated guinea pig ileum (GPI).</p><p><b>METHODS</b>The GPI contractions were recorded with a two-channel-physiological recorder with tension transducers. Cumulative dose-response curves of contractions of isolated GPI induced by histamine (Hist), acetylcholine (ACh) and potassium chloride (KCl) were constructed, then the influences of 323-A and 323-B on each curve were observed. Furthermore, possible mechanisms underlying effects of the two compounds were explored by analyzing their influences on the biphasic contractile response to ACh, with comparison of a calcium antagonist, verapamil (Ver).</p><p><b>RESULTS</b>The data indicated that both 323-A and 323-B inhibited the contractile actions of GPI triggered by Hist, ACh and KCl in a concentration-dependent manner, with pD2' values of 5.13, 4.97, 5.36 and 5.51, 5.56, 5.62, respectively. The initial phase component of the ACh-elicited contractions, in the absence of external Ca2+, was significantly reduced by 323-A, 323-B, as well as Ver, whereas the subsequent sustained tonic contractions induced by adding Ca2+ to the bath solution were almost unaffected.</p><p><b>CONCLUSION</b>These results suggest that 323-A and 323-B have calcium antagonistic effects similar to that of Ver in mechanisms, and they might have potential to be developed as calcium antagonists.</p>