肾虚不孕中医药研究思路探析

目的 :分析肾虚型排卵障碍或着床失败引起的不孕的中医药研究的方法和思路。方法 :从卵泡生长发育相关因素如IGF - 1mRNA、EGFmRNA ,卵泡基质崩解相关因素如MMPsmRNA、PAmRNA、PAI- 1mRNA等相关因素 ,以及与着床粘附有关的内膜细胞整合素β3mRNA表达等角度 ,探讨中医药治疗不孕的可能分子机制 ,并且各因素之间存在互动关系。结果 :补肾或补肾化瘀方药可能通过促进卵泡发育成熟 ,并诱发成熟卵泡破裂 ,稳定子宫内膜有利于孕卵着床等角度防治不孕。结论 :中医药治疗排卵障碍或着床失败所致不孕具有传统优势 ,提取分离补肾或补肾化瘀方药有效成分 ,从分子水平探讨中药复方有效成分对各指标互动关系影响作用 ,不孕研究可能取得重要进展。     

Cryo-EM structure of DNA-bound Smc5/6 reveals DNA clamping enabled by multi-subunit conformational changes

Structural maintenance of chromosomes (SMC) complexes are essential for chromatin organization and functions throughout the cell cycle. The cohesin and condensin SMCs fold and tether DNA, while Smc5/6 directly promotes DNA replication and repair. The functions of SMCs rely on their abilities to engage DNA, but how Smc5/6 binds and translocates on DNA remains largely unknown. Here, we present a 3.8 Å cryogenic electron microscopy (cryo-EM) structure of DNA-bound Saccharomyces cerevisiae Smc5/6 complex containing five of its core subunits, including Smc5, Smc6, and the Nse1-3-4 subcomplex. Intricate interactions among these subunits support the formation of a clamp that encircles the DNA double helix. The positively charged inner surface of the clamp contacts DNA in a nonsequence-specific manner involving numerous DNA binding residues from four subunits. The DNA duplex is held up by Smc5 and 6 head regions and positioned between their coiled-coil arm regions, reflecting an engaged-head and open-arm configuration. The Nse3 subunit secures the DNA from above, while the hook-shaped Nse4 kleisin forms a scaffold connecting DNA and all other subunits. The Smc5/6 DNA clamp shares similarities with DNA-clamps formed by other SMCs but also exhibits differences that reflect its unique functions. Mapping cross-linking mass spectrometry data derived from DNA-free Smc5/6 to the DNA-bound Smc5/6 structure identifies multi-subunit conformational changes that enable DNA capture. Finally, mutational data from cells reveal distinct DNA binding contributions from each subunit to Smc5/6 chromatin association and cell fitness. In summary, our integrative study illuminates how a unique SMC complex engages DNA in supporting genome regulation.

Structural maintenance of chromosomes (SMC) complexes are essential genome regulators in both prokaryotes and eukaryotes. In eukaryotes, the cohesin and condensin SMC complexes organize DNA, while the Smc5/6 complex (referred to as Smc5/6) directly regulates DNA replication and repair (1). At the structural level, SMC complexes share similarities while possessing unique attributes (1). Each complex contains a pair of SMC subunits and a set of non-SMC subunits. The SMC subunits define the tripartite filamentous architecture of the complex: their approximal 50-nm long coiled coil arm region connects their dimerized hinge and adenosine triphosphatase (ATPase) head regions (1). A non-SMC kleisin subunit uses its N- and C-terminal domains to link the head of one SMC to the head-proximal arm region (neck) of another SMC, forming a trimeric SMC-kleisin structure. In cohesin and condensin, two large U-shaped HEAT (Huntington, elongation factor 3, PR65/A, TOR) repeat HAWK (HEAT proteins associated with kleisins) subunits attach to the middle region of the kleisin. By contrast, the Smc5/6 kleisin (Nse4) binds to smaller WH (winged helix)-containing KITE (kleisin interacting tandem WH elements) subunits (Nse1 and Nse3) (2).SMC-mediated functions depend on interactions with DNA. Recent cryogenic electron microscopy (cryo-EM) structures of DNA-bound cohesin and condensin revealed that their HAWK subunits and the SMC head-neck regions form a clamp to enclose a single DNA double helix (3–7). DNA clamping can be critical for cohesin and condensin to extrude DNA loops for chromatin folding (5, 7–9). DNA loop extrusion additionally requires arm bending at a region called the elbow, which is found in both cohesin and condensin (5, 7–9). By contrast, a lack of arm bending in Smc5/6 was suggested by negative stain EM and cross-linking mass spectrometry (CLMS) data (10–14). Since Smc5/6 does not contain HAWK proteins nor shows arm-bending, it has remained unclear how Smc5/6 engages DNA to accomplish its multiple functions.Here we address the molecular mechanisms by which this unique SMC complex binds DNA using an integrative approach, coupling a cryo-EM-based structural characterization with CLMS analyses and functional investigation. Our atomic structure of a DNA-bound Saccharomyces cerevisiae Smc5/6 complex reveals that the head-neck Smc5-6 regions and the Nse1-3-4 subcomplex together form a clamp entrapping the DNA helix. The structure further reveals protein subunit folds and association, as well as how the subunits collaborate to entrap DNA. Comparison of CLMS analyses of DNA-free Smc5/6 with the structure of the DNA-bound Smc5/6 unveils large scale, multi-subunit conformational changes that enable Smc5/6 to encircle DNA. Finally, our mutational data suggest distinct contributions from each of the DNA binding regions to Smc5/6 chromatin association and cellular fitness. Comparison of our findings with those of other SMCs reveals that diverse SMC complexes use a similar DNA clamping strategy despite structural differences, and that Smc5/6 possesses unique features distinct from cohesin, condensin, and prokaryotic SMCs. Our work lays the foundation for an in-depth understanding of how Smc5/6 fulfills unique roles in genome protection.     

The impact of geographic unit of analysis on socioeconomic inequalities in cancer survival and distant summary stage – a population‐based study

Objective: When using area‐level disadvantage measures, size of geographic unit can have major effects on recorded socioeconomic cancer disparities. This study examined the extent of changes in recorded socioeconomic inequalities in cancer survival and distant stage when the measure of socioeconomic disadvantage was based on smaller Census Collection Districts (CDs) instead of Statistical Local Areas (SLAs). Methods: Population‐based New South Wales Cancer Registry data were used to identify cases diagnosed with primary invasive cancer in 2000–2008 (n=264,236). Logistic regression and competing risk regression modelling were performed to examine socioeconomic differences in odds of distant stage and hazard of cancer death for all sites combined and separately for breast, prostate, colorectal and lung cancers. Results: For all sites collectively, associations between socioeconomic disadvantage and cancer survival and distant stage were stronger when the CD‐based socioeconomic disadvantage measure was used compared with the SLA‐based measure. The CD‐based measure showed a more consistent socioeconomic gradient with a linear upward trend of risk of cancer death/distant stage with increasing socioeconomic disadvantage. Site‐specific analyses provided similar findings for the risk of death but less consistent results for the likelihood of distant stage. Conclusions: The use of socioeconomic disadvantage measure based on the smallest available spatial unit should be encouraged in the future. Implications for public health: Disadvantage measures based on small spatial units can more accurately identify socioeconomic cancer disparities to inform priority settings in service planning.     

Impact of National Centralized Drug Procurement Policy on Antiviral Utilization and Expenditure for Hepatitis B in China

Background and AimsThe National Centralized Drug Procurement (NCDP) policy was launched in mainland China in April 2019, with entecavir (ETV) and tenofovir disoproxil fumarate (TDF) being included in the procurement list. We conducted the current study to investigate the impact of the NCDP policy on the utilization and expenditures of antiviral therapy for chronic hepatitis B (CHB) in China.MethodsProcurement records, including monthly purchase volume, expenditure, and price of nucleos(t)ide analogs (NAs), were derived from the National Healthcare Security Administration from April 2018 to March 2021. The changes in volumes and expenditures of the first-line NAs and bid-winning products were calculated. The effects of price, volume, and structure related to drug expenditure were calculated by the Addis and Magrini (AM) Index System Analysis.ResultsThe purchase volume of NAs significantly increased from 134.3 to 318.3 million DDDs, whereas the expenditure sharply decreased from 1,623.41 to 490.43 million renminbi (RMB) or 241.94 to 73.09 million US dollars (USD). The proportions of first-line NAs rose from 72.51% (ETV: 69.00%, TDF: 3.51%) to 94.97% (ETV: 77.42%, TDF: 17.55%). AM analysis showed that the NCDP policy decreased the expenditure of all NAs (S=0.91) but increased that of the first-line NAs in the bid-winning list (S=1.13). Assuming the population size of CHB patients remains stable and a compliance rate of ≥75%, the proportion of CHB patients receiving first-line antiviral therapy would increase from 6.36–8.48% to 11.56–15.41%.ConclusionsThe implementation of the NCDP policy significantly increased the utilization of first-line NAs for CHB patients at a lower expenditure. The findings provided evidence for optimizing antiviral therapy strategy and allocating medical resources in China.     

心脑血管疾病用药不良反应与药品品种关系的聚类分析

目的寻找心脑血管疾病用药的不良反应与药品品种间聚类关系,促进临床安全合理用药。方法运用数据挖掘技术中的两阶段聚类算法对药品的严重不良反应与药品品种间的关系进行聚类分析。结果由聚类结果可知,在使用心脑血管疾病用药时,出现的严重和新的严重不良反应为肝功能异常、肾功能异常、呼吸困难、横纹肌溶解,导致这些严重不良反应的药物有受体类药物、钙离子拮抗剂、降低胆固醇类药物。结论在选择心脑血管疾病用药时,受体类药物、钙离子拮抗剂、降低胆固醇类药物应慎用、少用,尽量避免严重的不良反应发生。     

Phenotype of Asthma-COPD Overlap in COPD and Severe Asthma Cohorts

BackgroundAsthma and chronic obstructive pulmonary disease (COPD) are airway diseases with similar clinical manifestations, despite differences in pathophysiology. Asthma-COPD overlap (ACO) is a condition characterized by overlapping clinical features of both diseases. There have been few reports regarding the prevalence of ACO in COPD and severe asthma cohorts. ACO is heterogeneous; patients can be classified on the basis of phenotype differences. This study was performed to analyze the prevalence of ACO in COPD and severe asthma cohorts. In addition, this study compared baseline characteristics among ACO patients according to phenotype.MethodsPatients with COPD were prospectively enrolled into the Korean COPD subgroup study (KOCOSS) cohort. Patients with severe asthma were prospectively enrolled into the Korean Severe Asthma Registry (KoSAR). ACO was defined in accordance with the updated Spanish criteria. In the COPD cohort, ACO was defined as bronchodilator response (BDR) ≥ 15% and ≥ 400 mL from baseline or blood eosinophil count (BEC) ≥ 300 cells/μL. In the severe asthma cohort, ACO was defined as age ≥ 35 years, smoking ≥ 10 pack-years, and post-bronchodilator forced expiratory volume in 1 s/forced vital capacity < 0.7. Patients with ACO were divided into four groups according to smoking history (threshold: 20 pack-years) and BEC (threshold: 300 cells/μL).ResultsThe prevalence of ACO significantly differed between the COPD and severe asthma cohorts (19.8% [365/1,839] vs. 12.5% [104/832], respectively; P < 0.001). The percentage of patients in each group was as follows: group A (light smoker with high BEC) – 9.1%; group B (light smoker with low BEC) – 3.7%; group C (moderate to heavy smoker with high BEC) – 73.8%; and group D (moderate to heavy smoker with low BEC) – 13.4%. Moderate to heavy smoker with high BEC group was oldest, and showed weak BDR response. Age, sex, BDR, comorbidities, and medications significantly differed among the four groups.ConclusionThe prevalence of ACO differed between COPD and severe asthma cohorts. ACO patients can be classified into four phenotype groups, such that each phenotype exhibits distinct characteristics.     

右冠状动脉介入治疗的临床疗效及安全性观察

目的　观察右冠状动脉 (冠脉 )介入治疗 (PCI)的临床疗效及安全性。方法　回顾性分析 1995— 2 0 0 2年间进行的 188例 2 0 2处右冠脉靶血管介入治疗的特点。结果　 188例右冠脉病变共 2 0 2处右冠脉靶血管 ,靶血管介入成功率为 91 1%,其中 15 0例植入支架 174枚 ;PCI失败 18例 ,均发生在右冠脉近中段 ;室颤 2例 ,PCI后无复流现象 6例 ,早期急性冠脉闭塞 1例 ,冠脉破裂 3例 ,死亡 3例。随访 1～ 96月 ,绝大多数临床症状改善。结论　右冠脉病变的PCI是一项成功率高、并发症少、近远期临床疗效俱佳的治疗手段。