The roles of adulthood behavioural factors and familial influences in bone density among men

BACKGROUND. A primary strategy in osteoporosis prevention is advice on exercise, smoking, and calcium intake, although its practical value is unclear. AIM. To investigate the roles of such factors on bone density (BMD) after considering the influences of familial aggregation (combined effects of genetics and familial influences) in Finnish men 35-69 years old. METHODS. We selected 105 male monozygotic twin pairs, with discordance in suspected determinants. RESULTS. Dietary calcium was associated with BMD of the femoral neck; and body weight and lifetime frequency of endurance and ball game sport activities were associated with both femoral neck and lumbar BMD. Occupational loading and smoking were associated with neither. However, age and familial aggregation explained 73% of the variance of BMD in both the femoral neck and lumbar spine; calcium intake explained 1% in femoral neck and lifetime exercise 1% in lumbar spine. CONCLUSIONS. The effects of dietary calcium and physical activity that are not 'embedded' in the familial influences had very modest effects on the variance of BMD. Thus our chances of influencing BMD in later adulthood by targeting behavioural habits are likely to be limited. Interventions focused on childhood and the family unit may achieve more beneficial long-term results.     

成人脓毒血症患者不同负荷剂量的亚胺培南/西司他丁药动学/药效学参数差异的研究

目的 比较成人脓毒血症患者2h静脉泵入负荷量1.0g与2.0g亚胺培南/西司他丁的％T＞4×最低抑菌浓度(MIC),为制定亚胺培南/西司他丁在成人脓毒血症患者的合理用药方案提供参考.方法 对10位脓毒血症的患者随机分为实验组和对照组各5例.实验组受试者接受方案1给药即1.0g亚胺培南/西司他丁2.0h静脉泵入;对照组受试者接受方案2给药即2.0g亚胺培南/西司他丁2h静脉泵入.在给药前和给药后0.25、0.5、1、2、4、6、8h抽取静脉血标本测定血药浓度.结果 试验组对病原菌MIC为4、2、1 mg/L的％T＞4 ×MIC分别为分别为(19.89±4.10)％,(44.66 ±5.56)％,(68.97±7.47)％.对照组对病原菌MIC为4、2、1 mg/L的％T ＞4×MIC分别为(53.34±7.54)％,(79.45±8.66)％,(105.87 ±11.14)％.结论 ①结果提示2h静脉泵入负荷量2.0g亚胺培南/西司他丁的％T ＞4×MIC值超过静脉泵入1.0g;②随MIC值增加,％T ＞4×MIC呈下降趋势,对于MIC=4.0 mg/L的高病原菌感染,可采用亚胺培南/西司他丁负荷剂量2.0g2h给药.     

Predicting dynamic knee joint load with clinical measures in people with medial knee osteoarthritis

Knee joint loading, as measured by the knee adduction moment (KAM), has been implicated in the pathogenesis of knee osteoarthritis (OA). Given that the KAM can only currently be accurately measured in the laboratory setting with sophisticated and expensive equipment, its utility in the clinical setting is limited. This study aimed to determine the ability of a combination of four clinical measures to predict KAM values.Three-dimensional motion analysis was used to calculate the peak KAM at a self-selected walking speed in 47 consecutive individuals with medial compartment knee OA and varus malalignment. Clinical predictors included: body mass; tibial angle measured using an inclinometer; walking speed; and visually observed trunk lean toward the affected limb during the stance phase of walking. Multiple linear regression was performed to predict KAM magnitudes using the four clinical measures. A regression model including body mass (41% explained variance), tibial angle (17% explained variance), and walking speed (9% explained variance) explained a total of 67% of variance in the peak KAM.Our study demonstrates that a set of measures easily obtained in the clinical setting (body mass, tibial alignment, and walking speed) can help predict the KAM in people with medial knee OA. Identifying those patients who are more likely to experience high medial knee loads could assist clinicians in deciding whether load-modifying interventions may be appropriate for patients, whilst repeated assessment of joint load could provide a mechanism to monitor disease progression or success of treatment.     

胫腓骨手术后静脉自控镇痛两种追加负荷剂量方法的效果比较

目的观察胫腓骨手术后静脉自控镇痛两种追加负荷剂量方法的效果。方法将120例低位硬膜外麻醉胫腓骨手术患者按随机数字表分为两组,A组60例,硬膜外麻醉给药4h后,每隔10～15min按压自控镇痛笔1次,连续311;13组60例,术毕即刻遵医嘱给予镇痛负荷剂量舒芬太尼0．1μg／kg,当疼痛视觉模拟评分静息状态≥4分或活动状态≥6分,按压自控镇痛笔1次。比较两组患者术后上泵即刻、30rain、1h、2h、3h、6h、12h、24h、36h、48h静息及活动状态的镇痛评分、镇静评分及不良反应。结果A组术后3h、6h、12h静息及活动状态疼痛视觉模拟评分均低于B组,P〈0．05;镇痛不全A组5例、B组23例;两组患者镇静评分及不良反应发生率比较无统计学意义（P〉0．05）。结论单次硬膜外麻醉胫腓骨手术后静脉自控镇痛宜选定时定量持续给药。     

舒芬太尼用于胃肠外科手术患者术后镇痛的负荷剂量研究

目的观察胃肠外科手术患者应用舒芬太尼自控静脉镇痛(PCIA)不同负荷剂量术后镇痛的效果及不良反应,探讨舒芬太尼术后镇痛的最佳负荷剂量。方法择期胃肠外科全麻术后应用舒芬太尼PCIA镇痛患者60例,随机平均分为3组:负荷量5μg组(A组)、负荷量10μg组(B组)、负荷量20μg组(C组)。三组分别在手术结束前30 min给予不同的负荷剂量,在术毕拔管后开始PCIA,泵内舒芬太尼2μg/kg,患者自控镇痛(PCA)量2 mL/次,锁定时间15 min,背景量2 mL/h。记录术后1、4、12、24和48 h的疼痛评分、镇静评分、PCA按压次数、并发症和患者满意度等。结果术后1 h和4 h,B组与C组疼痛评分明显低于A组(P<0.05),C组镇静评分明显高于A组与B组(P<0.05)。术后12、24和48 h,三组疼痛及镇静评分差异无统计学意义。PCA按压次数在术后4 h内B组和C组少于A组(P<0.05),4～48 h三组比较差异无统计学意义。A组和B组恶心呕吐、嗜睡和腹胀发生率低于C组(P<0.05)。术后72 h患者满意度B组和C组明显高于A组(P<0.05)。结论手术结束前30 min给予静注负荷量舒芬太尼10μg镇痛效果良好,且不良反应少。     

An in vitro Model System to Study the Damaging Effects of Prolonged Mechanical Loading of the Epidermis

Pressure ulcers are areas of soft tissue breakdown that result from sustained mechanical loading of the skin and underlying tissues. Today, little is known with respect to the aetiology of these ulcers. This study introduces an in vitro model system to study the effects of clinically relevant loading regimes on damage progression in the epidermis, the uppermost skin layer. Engineered epidermal equivalents (EpiDerm) were subjected to 6.7 and 13.3 kPa for either 2 or 20 h using a custom-built loading device. Tissue damage was assessed by (1) histological examination, (2) tissue viability evaluation, and (3) by the release of a pro-inflammatory mediator, interleukin-1α (IL-1α). Loading the EpiDerm samples for 2 h increased the IL-1α release, although no visible tissue damage was observed. However, in the 20 h loading experiments visible tissue damage and a small decrease in tissue viability were observed. Furthermore, in these experiments the IL-1α release increased with magnitude of loading. It is concluded that this in vitro model system can be applied to improve insight in the epidermal damage process due to prolonged mechanical loading and can serve as a sound basis for effective clinical identification and prevention of pressure ulcers.     

载荷变化对口腔修复用纯钛摩擦磨损性能的影响

目的探讨载荷变化对纯钛与滑石瓷对磨时摩擦磨损性能的影响。方法使用MMV-1立式万能摩擦磨损试验机,以滑石瓷为对磨物,载荷设置为20、50、100N,在37℃人工唾液润滑的试验工况下,对口腔修复用纯钛进行二体摩擦磨损试验。记录动态摩擦系数。采用扫描电镜观察表面磨损形貌．X线衍射能谱仪分析磨屑成分．电子天平得出磨损量。结果纯钛与对磨物滑石瓷的磨损量及摩擦系数随载荷的增加而增大。载荷20N,纯钛的磨损机制主要为磨粒磨损：50N时,磨损机制是黏着磨损伴发磨粒磨损;100N时,纯钛磨损机制以黏着磨损为主。结论载荷增加可增大纯钛的磨损量．导致磨损机制改变,在高载荷条件下可发生严重黏着磨损．缩短纯钛修复体的使用寿命。     

加载时机对硬腭骨膜下种植体愈合结果的影响

目的研究硬腭骨膜下种植体加载时机对其愈合结果的影响。方法6只杂种猪分为3组,每组2只,每只植入4枚硬腭骨膜下种植体。分别于植入后4周、8周、12周时给予种植体9．8N的骀向持续载荷。加载4周后处死动物。测量从骨面去除每个种植体的拉出力,对标本进行组织学检查,拉出的种植体表面进行扫描电镜观察和能谱分析。结果21个植体成功愈合,3组种植体拉出力以中位数（四分位数间距）表示,依次为41．550（4．75）N,50．800（14．675）N和52．800（17．65）N（P〉0．05）。各组样本均存在三种愈合形式：炎性纤维愈合、纤维愈合和骨性愈合。炎性纤维愈合植体拉出力最小,而骨性愈合植体拉出力最大。结论对于愈合期在1个月以上的硬腭骨膜下种植体,加载时机不会显著影响其愈合结果;愈合类型对硬腭骨膜下种植体的结合强度起关键作用。     

Hertzian contact response of dentin with loading rate and orientation

OBJECTIVE: To test the hypothesis that dentin Hertzian contact response varies with loading rate and tubule orientation. DESIGN: Sound teeth (n=12) were cut either parallel or perpendicular to the axial direction to expose dentin (n=6 each). The cut specimens were embedded (poly-methyl-methacrylate (PMMA) and divided into two groups: (GL) load applied parallel to dentin tubule direction and (GP) load applied perpendicular to tubule direction. A 1.5mm diameter tungsten-carbide ball was used for Hertzian contact testing with a maximum load of 150 N load and loading rates of 0.1, 1, 100, and 1000 N/s on each specimen. Indented specimens were observed microscopically and photomicrographs acquired. Hertzian contact diameter and modulus were analysed (p<0.05) by one-way ANOVA and Tukey test. RESULTS: There were significant differences (p<0.05) in Hertzian response with respect to loading rate for GL (0.1N/s versus 1000 N/s, 0.1N/s versus 100 N/s, 1N/s versus 1000 N/s, and 1N/s versus 100 N/s), and GP (0.1N/s versus 1000 N/s, 0.1N/s versus 100 N/s, and 1N/s versus 1000 N/s). Contact modulus was higher for GL compared to GP at all loading rates (p<0.05). CONCLUSION: The results suggest that dentin contact modulus is loading rate dependent. Tubule orientation of dentin did not influence contact modulus values (p>0.05).