外源性肺表面活性物质对大鼠铜绿假单胞菌肺炎的作用研究

目的 :了解铜绿假单胞菌 (PA)肺炎大鼠的肺表面活性物质 (PS)及其组分的变化。观察外源性PS替代治疗对大鼠PA肺炎的作用。方法 :建立PA肺炎大鼠模型。将 5 1只雄性SD大鼠随机分为 3组 :肺炎大鼠PS治疗组 15只 (PS组 ) ;肺炎大鼠生理盐水气管内注入作阳性对照组 18只 (NS组 ) ;正常大鼠气管内注入生理盐水作正常对照组 18只 (NOR组 )。测各组大鼠肺组织湿 /干比 (W /D) ,观察病理学变化 ,作半定量中性粒细胞 (PMN)计数。分析支气管肺泡灌洗液 (BALF)中的PS成分 ,测定总磷脂 (TPL)、饱和磷脂酰胆碱 (DPPC)、总蛋白 (TP)。作BALF细菌培养及菌落计数。将NS组、NOR组各取 3只大鼠作肺组织电子显微镜切片制样。结果 :大体观和镜下观炎症程度PS组较NS组减轻。电镜发现NS组Ⅱ型肺泡上皮细胞内的管髓体脱落 ,PS层断裂。生化指标检测结果显示PS组与NS组相比 ,炎症呈改善趋势。BALF培养菌落计数 :PS组 (2 .4 3± 1.4 4 )× 10 4/ml,NS组 (10 .35± 2 .10 )× 10 4/ml,P <0 .0 5。结论 :外源性PS替代治疗使PA肺炎大鼠的肺组织炎症反应明显减轻 ,可能成为抗生素治疗严重或耐药性肺部感染的辅助用药     

慢性阻塞性肺疾病(COPD)模型大鼠肺组织中NLRP3炎症小体表达水平的变化及意义

目的 探讨NOD样受体热蛋白结构相关蛋白3(NLRP3)炎症小体在慢性阻塞性肺疾病(COPD)模型中的变化及意义。方法 将30只雄性大鼠随机分为2组,正常对照组(n=10只)给予自由饮水和摄食,喂养75天; 吸烟组(n=20只)采用单纯吸入香烟烟雾的方法制造大鼠COPD模型,连续75天后再根据大鼠最大呼气流速(PEF)及气道肺组织病理变化分为吸烟COPD组(n=9只)和吸烟非COPD组(n=11只)。收集支气管肺泡灌洗液(BALF)计算巨噬细胞(AMC)、中性粒细胞(NEU)和淋巴细胞(LYM)的绝对计数。采用酶联免疫吸附试验(ELISA)、逆转录-聚合酶链反应(RT-PCR)技术分别测定BALF,肺组织中NLRP3炎症小体的浓度以及NLRP3 mRNA的相对表达量。结果与正常对照组比较,吸烟非COPD组、吸烟COPD组BALF中NEU(×10⁶/L)(524.2±73.1,916.9±84.8 vs 106.6±31.8),AMC(×10⁶/L)(1 570.9±273.5,2 307.8±410.4 vs 496.6±61.7)和LYM(×10⁶/L)(72.1±14.7,115.4±23.8 vs 21.6±4.2),计数明显升高,吸烟COPD组BALF中NEU,AMC和LYM计数亦较吸烟非COPD组明显升高(F=350.59,100.57,82.63,均P<0.05)。与正常对照组比较,吸烟非COPD组、吸烟COPD组BALF(pg/ml)(107.8±23.5,126.7±34.9 vs 76.7±15.1),肺组织(pg/ml)(118.8±33.3,147.4±40.2 vs 84.1±21.5)中NLRP3炎症小体的浓度明显升高,与吸烟非COPD组比较,吸烟COPD组BALF,肺组织中NLRP3炎症小体的浓度亦明显升高(F=9.53,9.17,均P<0.05)。吸烟非COPD组和吸烟COPD组肺组织NLRP3 mRNA相对表达量均显著高于正常对照组(P<0.05),吸烟COPD组肺组织NLRP3 mRNA相对表达量显著高于吸烟非COPD组(P<0.05)。BALF,肺组织中NLRP3炎症小体浓度、肺组织NLRP3 mRNA相对表达量与NEU,AMC,LYM计数均呈显著正相关(P<0.05)。结论 NLRP3炎症小体参与了COPD慢性炎症的发生、发展,与肺组织炎症细胞以及气道病理改变密切相关,阻断NLRP3炎性小体的活化,有望成为治疗COPD新的靶点和方向。     

生长激素对酸吸入性肺损伤大鼠肺组织细胞凋亡的作用

目的 :观察生长激素 (GH )对盐酸吸入性急性肺损伤 (AL I)大鼠肺组织修复的作用机制。方法 :建立大鼠盐酸吸入性 AL I模型 ,84只大鼠随机分为生理盐水对照组 (NS组 )、盐酸损伤组 (HCl组 )、盐酸损伤 +生长激素干预组 (GH组 )。通过原位细胞检测技术评估肺组织细胞凋亡 ;用放射免疫方法检测大鼠血浆胰岛素样生长因子 1(IGF 1)、肿瘤坏死因子 α(TNFα)、白介素 8(IL 8)水平。结果 :经气道吸入盐酸可导致大鼠肺损伤 ,肺组织细胞凋亡现象明显 ,血浆 TNFα、IL 8水平均显著增高 ,注入盐酸后 0 .5小时 HCl组血浆TNFα和 IL 8分别为 (2 .17± 0 .4 1)μg/L和 (0 .91± 0 .0 8)μg/L ,GH组分别为 (3.14± 0 .2 8)μg/L和(0 .6 8± 0 .19)μg/L ,与 NS组比较均有显著性差异 (P<0 .0 5或 P<0 .0 1) ;GH组血浆 IGF 1水平明显高于HCl组〔(12 8.36± 30 .5 6 )μg/L比 (14 .19± 7.89)μg/L ,P <0 .0 5〕,肺组织细胞凋亡率明显低于 HCl组〔(16 .83± 3.0 3) %比 (2 0 .89± 1.36 ) % ,P<0 .0 5〕。结论 :盐酸吸入性 AL I大鼠肺组织细胞存在明显的凋亡现象。TNFα和 IL 8在 AL I肺组织细胞凋亡中起一定作用 ;血浆 IGF 1水平升高有利于肺组织的修复 ;生长激素对酸吸入性肺损伤大鼠肺组织细胞有明显的抗凋亡作用。     

颈动脉粥样斑块稳定性与急性脑梗死发病机制关系的临床研究

目的探讨颈动脉粥样斑块稳定性及炎症反应与急性脑梗死之间的关系。方法对71例急性脑梗死患者(A组)、44例无症状颈动脉硬化患者(B组)和21例健康对照者(C组)进行研究,ELISA测定基质金属蛋白酶-9(MMP-9)、组织型基质金属蛋白酶抑制剂-1(TIMP-1)含量,免疫透射比浊法测定高敏C反应蛋白(hs-CRP)含量,应用彩色多普勒超声仪观测颈动脉内中膜厚度(IMT)、斑块类型及斑块形态。结果A组颈动脉IMT[(1.11±0.29)mm]和B组IMT[(1.14±0.26)mm]与C组[(0.77±0.15)mm]比较差异有统计学意义(P<0.05);A组颈动脉斑块以脂质型斑块(59.2%)为主,B组以纤维型斑块(32.9%)为主,A组斑块表面多呈不规则型。hs-CRP、MMP-9含量在A组[分别为(5.47±2.26)mg/L、(250.64±89.65)ng/ml]、B组[分别为(1.80±0.34)mg/L、(144.67±34.40)ng/ml]、C组[分别为(0.59±0.12)mg/L、(64.49±18.26)ng/ml]之间差异有统计学意义;TIMP-1含量在A组[(59.64±15.87)ng/ml]、B组[(73.48±21.22)ng/ml]和C组[(57.95±7.86)ng/ml]之间差异有统计学意义,但A组和C组间差异无统计学意义;A组hs-CRP与MMP-9(r=0.241,P=0.043)呈正相关。结论颈动脉粥样斑块稳定性与急性脑梗死有关,MMP-9、TIMP-1参与的炎症反应是影响颈动脉粥样斑块由结构性不稳定向功能性不稳定进展的重要机制。     

急性肺损伤大鼠肺血管通透性的变化规律

目的:通过静脉注射脂多糖(LPS)建立大鼠急性肺损伤(ALI)模型,研究大鼠ALI时肺血管通透性的改变,探讨肺血管通透性改变的机制。方法:将大鼠随机分成对照组和LPS组。以LPS静脉注射建立ALI模型,对比观察0.5、2、4、6、8h后肺血管通透性、肺系数、肺水含量、支气管肺泡灌洗液(BALF)蛋白含量变化,光镜观察肺组织病理变化。结果:LPS组的肺血管通透性在0.5h后即高于对照组(P<0.05),2h后则显著高于对照组(P<0.01),8h达到高峰。LPS组的肺系数、肺水含量、BALF蛋白含量在2h后高于对照组(P<0.05),4h后则显著高于对照组(P<0.01),至6h达到顶峰。结论:LPS可以破坏肺血管内皮细胞屏障,导致肺血管通透性增加。但肺血管内皮细胞通透性和肺泡上皮细胞通透性在肺损伤时的变化并不完全同步,其原因需进一步探讨和研究。     

运动对OLETF大鼠血清肿瘤坏死因子的影响

目的　研究运动及高脂饮食对OLETF大鼠血清肿瘤坏死因子 α(TNF α)浓度的影响 ,探讨TNF α在运动改善机体胰岛素敏感性中所起的作用。方法　对 40只自发发病的 2型糖尿病模型———OLETF大鼠和 15只LETO大鼠进行 9周的运动和高脂饮食干预 ,9周后用放射免疫法测定每只大鼠血清中TNF α的浓度。结果　基础饲料饲养的OLETF大鼠非运动组和运动组TNF α浓度分别为 (0 .40 6± 0 .0 83)ng/ml和 (0 .5 74± 0 .116)ng/ml;高脂饲料饲养的OLETF大鼠非运动组和运动组TNF α浓度分别为 (0 .40 7± 0 .0 97)ng/ml和 (0 .5 13± 0 .0 98)ng/ml;而基础饲料饲养的LETO大鼠非运动组和运动组TNF α浓度分别为 (0 .387± 0 .0 87)ng/ml和 (0 .382± 0 .0 77)ng/ml;OLETF大鼠TNF α浓度运动组明显高于其相对应的非运动组 (P <0 .0 1) ,运动组和非运动组LETO大鼠TNF α浓度没有明显的差别。结论　运动能使OLETF大鼠TNF α浓度增加 ,而对LETO大鼠TNF α浓度没有明显影响 ;高脂饮食对OLETF大鼠TNF α浓度没有明显影响     

肺灌洗液中表面活性物质和炎症因子测定判断胸外科手术致肺损伤

目的:通过检测支气管肺泡灌洗液(BALF)中肺泡表面活性物质(PS)、肿瘤坏死因子-α(TNF-α)、白细胞介素-1β(IL-1β)及白细胞介素-8(IL-8)的含量研究开胸手术对肺造成的损伤及其机理。方法:开左胸行食管癌根治主动脉弓上吻合术患者24例,经纤维支气管镜灌洗肺泡(BAL),检测手术前后手术侧和非手术侧肺灌洗液(BALF)中PS组分和TNF-α、IL-1β和IL-8的变化,并同时检测手术前后血浆中上述细胞因子含量的变化。测定总磷脂(TPL)、饱和卵磷脂(SatPC)和总蛋白(TP)。取SatPC/TPL和SatPC/TP比值作为判断PS活性水平的指标。结果:术前左侧及右侧BALF中SatPC/TPL％和SatPC/TP％无显著差异(P>0.05);TNF-α(pmol·L~(-1)·mg~(-1)Pr)、IL-1β(μg·L~(-1)·mg~(-1)Pr)、IL-8(μg·L~(-1)·mg~(-1)Pr)含量均无显著差异(P>0.05)。手术后术侧肺SatPC/TPL及SatPC/TP值明显低于术前(30.15±11.91％ vs58 15±18.19％,P<0.01;6.54±2.94％ vs 12.28±2.44％,P<0.01),非手术侧SatPC/TPL及SatPC/TP比值无明显差异(P>0.05)手术侧肺术后BALF中TNF-α和IL-1β含量较术前明显上升(91.50±22.50 vs 45.80±11.69,P<0.01;0.89±0.24 vs 0.33±0.10,P<0.01),较对侧亦有明显上升(91.50±22.50 vs 51.90±11.99,P<0.01;0.89±0.24 vs0.38±0     

肺表面活性物质稀释剂延迟肺灌洗治疗烟雾吸入性损伤

目的 探讨外源性肺表面活性物质(PS)稀释剂延迟肺灌洗对大鼠严重烟雾吸入伤后内源性PS功能障碍和急性呼吸衰竭的治疗效果.方法 90只Wistar大鼠随机分为5组:Ⅰ组,正常对照(n=14);Ⅱ组,烟雾吸入(n=27);Ⅲ组,烟雾+PS灌洗+机械通气(MV),n=21;Ⅳ组,烟雾+盐水灌洗+MV,n=10;V组,烟雾+MV,n=18.伤后2 h经气管插管注入含PS(100ms/ks)的等渗盐水30 ml/kg或等量盐水行肺灌洗,MV 4 h,观察24 h;检测动脉血气、肺水量、静态肺顺应性(Cst)、支气管肺泡灌洗液(BAIF)蛋白含量、BALF表面张力特性和24 h病死率等.结果 致伤动物伤后立即出现严重缺氧和一氧化碳中毒;Ⅱ组发生急性呼吸衰竭、高通透性肺水肿和PS功能障碍;Ⅲ组Cst和BALF表面张力特性显著改善(P<0.05),但氧合能力、肺水量和BALF蛋白含量无明显好转(P>0.05).Ⅳ、V组疗效不佳.结论 外源性PS稀释剂延迟肺灌洗可一定程度恢复烟雾吸入所致内源性PS功能抑制,改善肺功能,但不能显著减轻高通透性肺水肿和呼吸衰竭,不能降低早期病死率.     

小剂量氢化可的松与血必净对急性肺损伤大鼠作用比较

目的观察小剂量氢化可的松与血必净注射液对大肠埃希菌导致的大鼠急性肺损伤(ALI)的保护作用。方法大肠埃希菌[O111B4,(4.4~5.6)×1012CFU/L]3 ml/kg气管注射制作大鼠肺内源性ALI模型,设氢化可的松干预组[HC组,腹腔注射氢化可的松5 mg/(kg·d),共2天]、血必净干预组[X组,腹腔注射血必净注射液5 ml/(kg·d),共2 d]、模型对照组[C组,腹腔注射生理盐水5 ml/(kg·d),共2天]、正常对照组[N组,气管注射3 ml/(kg·d)生理盐水,腹腔注射生理盐水5 ml/(kg·d),共2天]。各组分别于末次给药后12 h放血处死动物,留血清测TNF-α、IL-8水平。取左肺计算肺指数。结果 (1)HC组、X组、C组病死率无统计学意义(χ~2=0.194,P=1.000);(2)TNF-α水平:HC组及X组[分别为(80.31±11.87)ng/L,(89.42±22.76)ng/L]均明显低于C组[(125.68±27.91)ng/L](P<0.05),HC组与X组差别无统计学意义(P>0.05);(3)IL-8水平:HC组与X组[分别为(175.01±40.29)ng/L,(214.38±56.03)ng/L]均明显低于C组[(266.48±56.09)ng/L](P<0.05),HC组与X组差别无统计学意义(P>0.05);(4)肺指数:HC组与X组[分别为(0.318±0.058)%,(0.352±0.046)%]均明显低于C组[(0.412±0.055)%](P<0.05),HC组与X组差别无统计学意义(P>0.05)。结论小剂量氢化可的松及血必净治疗大肠杆菌导致的大鼠ALI均能明显降低血清促炎因子的水平,减轻肺水肿,两者作用相似。     

输血相关急性肺损伤对大鼠血浆和肺组织血管生成素-2表达的影响

目的探讨输血相关急性肺损伤(TRALI)时血浆和肺组织中血管生成素-2(Ang-2)的表达及其意义。方法选择60只SD大鼠,按随机数字表法分为生理盐水(NS)对照组、脂多糖(LPS)对照组、TRALI模型组、急性肺损伤(ALI)对照组,每组15只。采用"LPS-血浆二次打击"法复制TRALI大鼠模型。NS对照组腹腔注射NS 2 mL,移除大鼠血液1 mL后输注等体积NS。LPS对照组大鼠腹腔注射2 mg/kg LPS(1 min内注完)1 mL 2 h后静脉输注等体积NS。TRALI模型组腹腔注射2 mg/kg LPS 1 mL,2 h后静脉输注血浆1 mL。ALI对照组静脉输注5 mg/kg LPS 1 mL诱导ALI。制模完成后处死大鼠取肺组织观察病理学改变并进行肺损伤评分;取支气管肺泡灌洗液(BALF)检测细胞总数、中性粒细胞比例(NEUT);用蛋白质免疫印迹试验(Western Bolt)检测血浆中Ang-2蛋白表达;免疫组化法观察肺组织中Ang-2阳性表达;实时荧光定量反转录-聚合酶链反应(RT-PCR)检测大鼠肺组织中Ang-2 mRNA表达水平。结果光镜下可见,NS对照组大鼠肺组织结构清楚,肺泡壁结构完整,肺泡内未见炎性细胞渗出及肺泡萎陷,肺泡间隔均一无增宽;LPS对照组肺泡间隔轻度增宽、有少量炎性细胞浸润;TRALI模型组肺泡间隔增宽、中等量出血并有较多炎性细胞浸润;ALI对照组肺内大量炎性细胞浸润,间质水肿加重,伴出血、微血栓及灶性肺不张。ALI对照组、TRALI模型组血浆Ang-2蛋白和肺组织Ang-2 mRNA表达均显著高于NS对照组、LPS对照组[Ang-2蛋白(灰度值):0.58±0.09、0.43±0.07比0.12±0.03、0.20±0.05,Ang-2 mRNA(2~(-ΔΔCt)):0.39±0.10、0.29±0.09比0.10±0.05、0.16±0.04,P均0.01];ALI对照组、TRALI模型组BALF细胞总数(×10~6/L:361±78、310±76比101±63、165±65)、NEUT(0.396±0.125、0.335±0.115比0.098±0.035、0.114±0.041)均明显高于NS对照组和LPS对照组(P均0.05);ALI对照组、TRALI模型组病理学评分、肺湿重/体重比值和动脉血氧分压(PaO_2)均显著高于NS对照组和LPS对照组(P均0.05)。ALI对照组与TRALI模型组各项指标比较差异无统计学意义(P均0.05)。结论TRALI大鼠肺组织和血浆中Ang-2的表达升高,提示Ang-2可能参与了TRALI病理生理过程。     

Determination of creatine kinase isoenzyme MB activity in serum using immunological inhibition of creatine kinase M subunit activity. Activity kinetics and diagnostic significance in myocardial infarction.

This is a new method for the determination of creatine kinase isoenzyme MB activity in serum. The method uses direct activity measurement of creatine kinase B subunit activity after blocking of CK-M subunit activity by inhibiting antibodies. The test takes no longer than 15 min. The method yields an intra-serial C.V. of 2.0-12.9%, and a C.V. from day to day of 5.5%. The detection limit is 3.4 U/l creatine kinase MB. In the 95 cases with proven myocardial infarction several types of creatine kinase MB activity kinetics could be determined. The percentage of creatine kinase MB of peak CK-total is 6-25%, with a mean of 11.1%. The amount of creatine kinase MB with respect to total CK activity after reinfarction is higher than the amount after initial infarction.     

Dissociable correlates of two classes of retrieval processing in prefrontal cortex

Although substantial evidence suggests that the prefrontal cortex (PFC) implements processes that are critical for accurate episodic memory judgments, the specific roles of different PFC subregions remain unclear. Here, we used event-related functional magnetic resonance imaging to distinguish between prefrontal activity related to operations that (1) influence processing of retrieval cues based on current task demands, or (2) are involved in monitoring the outputs of retrieval. Fourteen participants studied auditory words spoken by a male or female speaker and completed memory tests in which the stimuli were unstudied foil words and studied words spoken by either the same speaker at study, or the alternate speaker. On "general" test trials, participants were to determine whether each word was studied, regardless of the voice of the speaker, whereas on "specific" test trials, participants were to additionally distinguish between studied words that were spoken in the same voice or a different voice at study. Thus, on specific test trials, participants were explicitly required to attend to voice information in order to evaluate each test item. Anterior (right BA 10), dorsolateral prefrontal (right BA 46), and inferior frontal (bilateral BA 47/12) regions were more active during specific than during general trials. Activation in anterior and dorsolateral PFC was enhanced during specific test trials even in response to unstudied items, suggesting that activation in these regions was related to the differential processing of retrieval cues in the two tasks. In contrast, differences between specific and general test trials in inferior frontal regions (bilateral BA 47/12) were seen only for studied items, suggesting a role for these regions in post-retrieval monitoring processes. Results from this study are consistent with the idea that different PFC subregions implement distinct, but complementary processes that collectively support accurate episodic memory judgments.     

俯卧位通气对高海拔地区肺复张治疗无效急性呼吸窘迫综合征患者氧合的影响

目的 探讨俯卧位通气对高海拔地区肺复张术(RM)治疗无效急性呼吸窘迫综合征(ARDS)患者的治疗作用.方法 从海拔2260m的地区医院筛选RM治疗无效的41例ARDS患者[平均氧合指数( PaO2/FiO2)较RM前升高＜20％视为RM无效],依不同病因分为肺内源性ARDS组(ARDSp组)和肺外源性ARDS组(ARDSexp组),每组再按信封法随机分为俯卧位组和仰卧位组,即ARDSp俯卧位组(11例)、ARDSp仰卧位组(9例)、ARDSexp俯卧位组(10例)、ARDSexp仰卧位组(11例).在通气前及通气1、2、3、4h监测动脉血氧分压( PaO2)、PaO2/FiO2、静态顺应性(Cst)、气道阻力(Raw)的变化.结果 通气lh时,ARDSexp俯卧位组PaO2/FiO2( mm Hg,l mm Hg=0.133 kPa)即较通气前显著升高(157.4±40.6比129.3±48.7,P＜0.05),并随通气时间延长呈持续增高趋势,4h达峰值(219.1 ±41.1);且ARDSexp俯卧位组通气3h内PaO2/FiO2较其他3组显著增高,另3组间则差异无统计学意义.ARDSp俯卧位组、ARDSexp俯卧位组通气4h时PaO2/FiO2均较相应仰卧位组显著增高(208.8±39.7比127.4±47.1,219.1±41.1比124.9±50.8,均P＜0.05).4组通气前后Cst无显著改变,各组间差异也无统计学意义.ARDSp俯卧位组通气4h时Raw(cmH2O·L-1·s-1)较通气前显著降低(6.8±1.7比10.7±1.8,P＜0.05),且明显低于其他3组;其他3组各时间点Raw组内及组间比较差异均无统计学意义.结论 俯卧位通气作为ARDS机械通气重要策略之一,可以改善RM无效高原ARDS患者的氧合,为抢救患者赢得宝贵的时间.     

Digital imaging among medical facilities

The Department of Veterans Affairs (VA) in the USA operates a network of 172 medical centres which all utilize a hospital information system (HIS) which has been developed and is currently maintained by the VA. During the past several years, an image management and communication module has been developed, installed and clinically utilized at the Washington DC and Maryland VA Medical Centres. This image management and communication system, referred to as the decentralized hospital computer program (DHCP) imaging system, is fully integrated with a commercial picture archiving and communication system (PACS). The system is utilized to capture, archive, and display all images generated within the hospital including radiology, nuclear medicine, pathology, endoscopy, bronchoscopy, and dermatology, intraoperative photographs, ECG data, and a limited number of paper documents. The ultimate goal of the project is to have all patient text and image data available at any clinical workstation to any authorized user anywhere within the network of medical centres. Clinical requirements for an imaging workstation include ease of use, rapid and reliable access to the complete set of patient information, and images which are of acceptable quality to meet the requirements of the user and the subspecialty. Patient confidentiality and data security must be safeguarded at all times. Integration of the images with the remainder of the patient's database was found to be critical to the success of the project. The experience at the Washington and Maryland facilities suggests that an imaging system that is successfully integrated with a hospital information system can provide substantial clinical and economic benefits both within and among medical centres. Clinical acceptance and utilization of the system has been excellent, particularly in diagnostic radiology where DHCP Imaging has been interfaced to a commercial PAC system. Based upon this initial experience, the VA has begun to deploy the system throughout its large network of medical centres.     

Myocardial elastography at both high temporal and spatial resolution for the detection of infarcts

Myocardial elastography is a novel method for noninvasively assessing regional myocardial function, with the advantages of high spatial and temporal resolution and high signal-to-noise ratio (SNR). In this paper, in-vivo experiments were performed in anesthetized normal and infarcted mice (one day after left anterior descending coronary artery [LAD] ligation) using a high-resolution (30 MHz) ultrasound system (Vevo 770, VisualSonics Inc., Toronto, ON, Canada). Radiofrequency (RF) signals of the left ventricle (LV) in longitudinal (long-axis) view and the associated electrocardiogram (ECG) were simultaneously acquired. Using a retrospective ECG gating technique, 2-D full field-of-view RF frames were acquired at an extremely high frame rate (8 kHz) that resulted in high-quality incremental displacement and strain estimation of the myocardium. The incremental results were further accumulated to obtain the cumulative displacements and strains. Two-dimensional and M-mode displacement images and strain images (elastograms), as well as displacement and strain profiles as a function of time, were compared between normal and infarcted mice. Incremental results clearly depicted cardiac events including LV contraction, LV relaxation and isovolumetric phases in both normal and infarcted mice, and also evidently indicated reduced motion and deformation in the infarcted myocardium. The elastograms indicated that the infarcted regions underwent thinning during systole rather than thickening, as in the normal case. The cumulative elastograms were found to have higher elastographic SNR (SNR(e)) than the incremental elastograms (e.g., 10.6 vs. 4.7 in a normal myocardium, and 6.0 vs. 2.4 in an infarcted myocardium). Finally, preliminary statistical results from nine normal (m = 9) and seven infarcted (n = 7) mice indicated the capability of the cumulative strain in differentiating infracted from normal myocardia. In conclusion, myocardial elastography could provide regional strain information at simultaneously high temporal (>/=0.125 ms) and spatial ( approximately 55 microm) resolution as well as high precision ( approximately 0.05 microm displacement). This technique was thus capable of accurately characterizing normal myocardial function throughout an entire cardiac cycle, at the same high resolution, and detecting and localizing myocardial infarction in vivo.     

Guns and Knives in New Mexico: Patterns of Penetrating Trauma, 1978–1993

Objective: To identify patterns of nonfatal and fatal penetrating trauma among children and adults in New Mexico using ED and medical examiner data.
Methods: The authors retrospectively sampled in 5-year intervals all victims of penetrating trauma who presented to either the state Level-1 trauma center or the state medical examiner from a 16-year period (1978–1993). Rates of nonfatal and fatal firearm and stabbing injury were compared for children and adults.
Results: Rates of nonfatal injury were similar (firearm, 34.3 per 100,000 person-years; stabbing, 35.1). However, rates of fatal injury were significantly different (firearm, 21.9; stabbing, 2.7; relative risk: 8.2; 95% confidence interval: 5.4, 12.5). From 1978 to 1993, nonfatal injury rates increased for children (p = 0.0043) and adults (p < 0.0001), while fatal penetrating injury remained constant. The increase in nonfatal injury in children resulted from increased firearm injury rates. In adults, both stabbing and firearm nonfatal injury rates increased.
Conclusions: Nonfatal injury data suggest that nonfatal violence has increased; fatal injury data suggest that violent death rates have remained constant. Injury patterns vary by age, mechanism of trauma, and data source. These results suggest that ED and medical examiner data differ and that both are needed to guide injury prevention programs.