锶对骨矿代谢的研究进展

锶是人体的必须微量元素之一,在骨代谢中具有双重调节作用,既可增加骨的形成,又可抑制骨的吸收,其作用机制也被广泛研究。文章旨在对锶与骨矿代谢关系的研究进行综述,为其更广泛地用于临床提供理论基础。     

从“脑-肝-血管”轴初步探讨肝藏血、主疏泄的机制

“肝藏血,主疏泄”是中医藏象学说的重要内容,在中医辨证论治诸多疾病中应用广泛,尤其在高血压病的从肝论治方面。然其调节血压、调节肝血流的具体机制,调节血压血流的途径、部位等尚不甚明确。收集国内外相关文献,从“脑-肝-血管”轴的角度,基于肝血管和生理、神经支配等方面,初步探讨其“藏血、主疏泄”的机制,及两者之间的关系,为今后相关深入基础机制研究提供思路。     

抗结核药物的研究进展

随着结核病耐药频率不断升高,结核病治疗面临严峻的挑战,因此,研发新型抗结核药物显得尤为重要。在过去十年中,抗结核药物的研发取得了重要进展。本文将对近年来被批准用于临床和正在进行临床试验的新化学实体按靶点进行分类,并综述其作用机制、体内外药理活性、药代动力学性质以及临床研究结果。对抗结核药物的研发进行了展望,以期对结核病药物研发提供参考。     

炎症性肠病相关结直肠肿瘤发生机制研究进展

近年来的研究显示,炎症性肠病并发结直肠肿瘤的可能性增加,其发病机制尚未明确。遗传物质、炎症因子、信号通路以及肠道菌群等的一系列改变和相互作用被认为可能在炎症性肠病相关的癌变进程中发挥重要作用。本文从流行病学、危险因素、疾病发生机制等方面阐述炎症性肠病与肿瘤发生的相关性。     

The Analgesic Role of Calcitonin Following Osteoporotic Fracture

Osteoporosis is a systemic skeletal condition characterized by decreased bone strength with consequent increased susceptibility to bone fracture. Fragility fractures in osteoporosis are often painful and result in loss of quality of life and disability. Salmon calcitonin (SCT) is a natural hormone that may assist in the management of osteoporotic patients following fracture by reducing fracture risk and decreasing pain. SCT is an antiresorptive agent which has been shown to reduce the risk of vertebral fractures (by 36%) in postmenopausal women with osteoporosis and previous fractures, with a safety profile comparable to placebo over long-term use. Clinical evidence suggests that SCT (with either subcutaneous and intranasal delivery) is an analgesic for the acute pain following osteoporotic fracture. Pain relief with SCT occurs after 1 week or less of treatment. Associated with this pain relief, vertebral fracture patients receiving SCT have been observed to have earlier mobilization compared with those receiving a placebo. Both preclinical and clinical data suggest a central analgesic effect for SCT. The mechanism(s) by which SCT induces pain relief has (have) not been conclusively shown. Neither a direct receptor-mediated action nor an indirect endorphin-mediated effect can be ruled out. Received: 26 October 2001 / Accepted: 17 June 2002 Correspondence and offprint requests to: Stuart Silverman, MD, 8641 Wilshire Blvd, Suite 301, Beverly Hills, CA 90211, USA. e-mail: stuarts@omcresearch.org     

生精细胞凋亡的分子机制研究

生精过程中细胞凋亡过程对维持正常的精子生成至关重要,该过程的失衡是导致少精子无精子症的重要机制之一,已受到广泛关注。哺乳动物生精细胞凋亡过程中通过胱门蛋白酶的主要涉及三条途径,分别是与细胞色素C相关的内源性凋亡通路、涉及死亡受体及其配体的外源性通路和与内质网(ER)相关的第三条途径。本文就睾丸生精细胞凋亡的分子机制的研究情况作一综述,并提出生殖细胞凋亡机制存在的问题及研究前景。     

吸入麻醉药作用机制的5埃理论

在过去的20多年中,对吸入麻醉药作用机制的合理解释大量增多,同时也提出了更多目前还不能回答的问题。Eger等提出了吸入麻醉药产生对伤害性刺激无体动反应的作用靶位可能是两个相距5埃的位点的假设,简称5埃理论。现就相关问题作一综述。     

Backside Wear in Modern Total Knee Designs

Although modularity affords various options to the orthopedic surgeon, these benefits come at a price. The unintended bearing surface between the back surface of the tibial insert and the metallic tray results in micromotion leading to polyethylene wear debris. The objective of this study was to examine the backside wear of tibial inserts from three modern total knee designs with very different locking mechanisms: Insall-Burstein II® (IB II®), Optetrak®, and Advance®. A random sample of 71 inserts were obtained from our institution’s retrieval collection and examined to assess the extent of wear, depth of wear, and wear damage modes. Patient records were also obtained to determine patient age, body mass index, length of implantation, and reason for revision. Modes of wear damage (abrasion, burnishing, scratching, delamination, third body debris, surface deformation, and pitting) were then scored in each zone from 0 to 3 (0 = 0%, 1 = 0–10%, 2 = 10–50%, and 3 = >50%). The depth of wear was subjectively identified as removal of manufacturing identification markings stamped onto the inferior surface of the polyethylene. Both Advance® and IB II® polyethylene inserts showed significantly higher scores for backside wear than the Optetrak® inserts. All IB II® and Advance® implants showed evidence of backside wear, whereas 17% (5 out of 30) of the retrieved Optetrak® implants had no observable wear. There were no significant differences when comparing the depth of wear score between designs. The locking mechanism greatly affects the propensity for wear and should be considered when choosing a knee implant system.Key words: polyethylene, wear, knee, backside, back surface, locking mechanism     

单次与多次缺血后处理对肺缺血再灌注损伤的实验研究

目的观察不同周期的缺血后处理（IP）对肺缺血再灌注损伤（LIRI）的影响，寻找具有最佳肺保护功能的IP周期和时机，并探讨IP对LIRI作用的机制，为临床提供实验依据。方法48只Wistar大鼠随机分为6组，每组8只。对照组、缺血再灌注（IR）组、IP-Ⅰ-IP-Ⅳ组，测定肺组织湿／干重比（W／D）、丙二醛（MDA）含量、一氧化氮合酶（NOS）、超微量Na^＋-K^＋-ATP酶活性，并在光镜下观察肺组织结构变化。结果IP-Ⅱ、IPⅢ组相比，差异无统计学意义（P〉0．05）；但较IR组、IP－Ⅰ、IP－Ⅳ组的MDA含量明显降低，Na^＋-K^＋-ATP酶活性明显升高（P〈0．05）。光镜下可见IP-Ⅱ、IP-Ⅲ组肺泡和支气管壁充血水肿较IR组和IP-Ⅰ、Ⅳ组明显减轻。结论IP对大鼠LIRI具有保护作用，尤其以给予Ⅱ、Ⅲ周期的30S再灌、30s停灌的IP具有较好的肺保护效果，并推测在缺血后立即给予2-3min的IP肺保护效果好。其机制可能与抑制活性氧自由基（ROS）和iNOS的生成，诱导Na^＋-K^＋-ATP酶活性升高有关。     

Preventive effects of perioperative parecoxib on post-discectomy pain

BACKGROUND: Cyclooxygenase inhibitor treatment is viewed increasingly critical because of safety considerations, and there are several open questions on their optimal use. METHODS: In a randomized placebo-controlled study in 320 patients undergoing discectomy, we administered parecoxib 40 mg either perioperatively (before operation and after operation), after operation (first dose given in the evening after surgery), or before operation (single parecoxib dose given 45 min before surgery). We measured the main outcome variables: average pain score, morphine consumption, and opioid-related symptom distress at 25, 49, and 73 h after surgery. RESULTS: Perioperative parecoxib significantly (i) improved the pain score compared with both placebo and postoperative parecoxib, (ii) decreased morphine consumption, and (iii) reduced the opioid-related symptom distress score. Neither a single preoperative dose nor postoperative parecoxib (first dose given in the evening after surgery) significantly improved morphine's analgesic effectiveness. CONCLUSIONS: Perioperative parecoxib compared with postoperative parecoxib improves post-discectomy pain and results in a reduction in adverse effects associated with opioid therapy. Postoperative parecoxib, or a single pre-incisional parecoxib dose, does not significantly improve post-discectomy pain or opioid side-effects up to 3 days after surgery.