ABSTRACT
In eukaryotes, the basic structural unit of chromatin is the nucleosome, and genomic DNA iscompressed in chromatin. The presence of nucleosomes usually inhibits the biological processes that occuron the DNA templates, such as transcription, replication, repair, and recombination,. The histonevariant H2A.Z can regulate the structure of chromatin and affect the transcription process of genes, but itsdetailed regulation mechanism remains unclear. In this paper, the method of Förster resonance energytransfer (FRET) was used to detect the influence of sodium chloride, potassium chloride, manganesechloride, calcium chloride and magnesium chloride on the dissociation of nucleosomes. Then, the stabilitydifferences between the nucleosomes containing the histone variant H2A. Z and the conventionalnucleosomes were compared under the action of salt ions. Widom 601 DNA sequence was labeled withdual fluorescence Cy3 and Cy5, and the dissociation of nucleosomes was reflected by the change offluorescence signal value. FRET results showed that the dissociation speed of nucleosomes containing thehistone variant H2A. Z under the action of sodium chloride, potassium chloride, manganese chloride, calcium chloride and magnesium chloride is slower than that of canonical nucleosomes, and the influenceof calcium chloride, manganese chloride and magnesium chloride on dissociation is more obvious thansodium chloride, potassium chloride. The results of electrophoresis analysis showed that the dissociationrate of nucleosomes containing histone variant H2A. Z was significantly lower than that of canonicalnucleosomes at 75℃. Fluorescence thermal shift (FTS) was used to further analyze the stability ofnucleosomes containing histone variant H2A.Z. It was found that the fluorescence signals of the two typesof nucleosomes showed two distinct growth periods, and the fluorescence signals generated in thedissociation process of the two types of nucleosomes showed two distinct growth periods. The temperaturecorresponding to the first increasing period of fluorescence signal in the dissociation process of H2A. Z-containing nucleosome is significantly higher than that in the dissociation process of the canonicalnucleosome, which indicated that the dissociation and denaturation temperature of the H2A.Z / H2B dimerin the nucleosome is higher than that of the canonical H2A / H2B dimer, and the H2A. Z-containingnucleosomes have high thermal stability. The results indicated that the structure of nucleosomes containingthe histone variant H2A.Z is more stable than that of canonical nucleosomes.
ABSTRACT
In recent years, with the rapid development of economy and the change of life style, the prevalence rate of diabetes has increased year by year, which has become a worldwide problem threatening the health of all mankind. According to epidemiological studies, most patients with diabetes are mainly type 2 diabetes mellitus(T2DM), accompanied by insulin resistance and insufficient insulin secretion. The interaction of many factors such as inflammation, obesity, oxidative stress and apoptosis leads to the occurrence of insulin resistance. At present, the commonly used hypoglycemic drugs include insulin and related preparations, biguanides, sulfonylureas, α-glycosidase inhibitors, glinids, thiazolidinediones, dipeptidyl peptidase-Ⅳinhibitors and so on. Although appropriate exercise, lifestyle changes and oral hypoglycemic drugs are effective in the treatment of mild T2DM. However, long-term and combined medication is needed for patients with severe diabetes or with related complications, which increases the risk of drug side effects and adverse reactions. Chinese herbal medicine has been used in China for thousands of years, such as Huanglian jiedutang and Yangyin Jianpitang. Similarly, many single traditional Chinese medicines also have their own advantages in the treatment of T2DM, such as Ophiopogonis Radix，Ginseng Radix et Rhizoma，Momordica Charantia，Euodiae Fructus，Alismatis Rhizoma，Astragali Radix，Notoginseng Radix et Rhizoma，Anemarrhenae Rhizoma，Dioscoreae Rhizoma and other traditional Chinese medicines have ideal effects in reducing blood sugar and improving insulin resistance. However, the active substances and targets in a considerable number of prescriptions or single medicines are not clear. Recently, more and more natural products have been proved to have anti-T2DM properties, and their possible therapeutic mechanisms have been explored. The purpose of this paper is to comprehensively review the effects and related targets of natural active substances such as flavonoids, polyphenols, alkaloids, terpenoids, polysaccharides and quinones on T2DM, and to provide theoretical support for better research and development of drugs for the treatment of diabetes and its complications.
ABSTRACT
Objective To compare the clinical effect between olecranon osteotomy and bilateral triceps brachii approach combined with bilateral locking plate in the treatment of type C3 distal humerus fracture.Methods Forty-five patients with type C3 distal humerus fracture were performed with operation and follow-up in Department of Osteology of the First People's Hospital of Xinxiang City from July 2006 to February 2016.The patients were divided into olecranon osteotomy group (n =25) and bilateral triceps brachii approach group (n =20).The patients in olecranon osteotomy group were treated with olecranon osteotomy combined with bilateral locking plate,and the patients in bilateral triceps brachii approach group were treated with bilateral triceps brachii approach combined with bilateral locking plate.The incision length,operation time,hospitalization time,fracture healing time,postoperative complications and the score of elbow joint function were compared between the two groups.Results There was no significant difference in the mean follow-up time between the two groups (P ＞ 0.05).The incision length in olecranon osteotomy group was significantly shorter than that in bilateral triceps brachii approach group(P ＜ 0.05).There was no significant difference in the operation time,hospitalization time and fracture healing time between the two groups (P ＞ 0.05).There was one case of infection and two cases of heterotopic ossification in the olecranon osteotomy group,and the incidence of postoperative complications was 12.0％ (3/25).There was one case of heterotopic ossification,one case of fracture delayed union and one case of elbow joint stiffness in the bilateral triceps brachii approach group,and the incidence of postoperative complications was 15.0％ (3/20).There was no significant difference in the incidence of postoperative complications between the two groups (x2 =0.087,P ＞ 0.05).At the end of the follow-up,the excellent rate of the Mayo score of elbow joint function in the olecranon osteotomy group and bilateral triceps brachii approach group was 88.0％ (22/25) and 55.0％ (11/20) respectively,the excellent rate in the olecranon osteotomy group was significantly higher than that in the bilateral triceps brachii approach group (x2 =6.188,P ＜ 0.05).Conclusion Compared with the bilateral triceps brachii approach,the olecranon osteotomy combined with bilateral locking plate fixation is more beneficial to the recovery of elbow joint function in patients with type C3 distal humerus fracture.