改良后的家兔动脉深低温保存实验研究

目的：为探讨家兔动脉在改良的深低温保存后，其作为血管材料替代物的优越性。方法：无菌条件下取新鲜兔动脉，分别给予改良后的营养液经慢速深低温冷冻和快速深低温冷冻处理，6个月后异体和自体移植，12周后，取移植的血管组织，观测其组织活性，组织形态、血管通畅率。结果：改良的营养液保护的血管经慢冻法处理后与自体血管活性相近，经改良的营养液保护的血管，移植前后血管内膜的连续性，血管的组织结构良好；慢冻法处理的血管通畅率比速冻法处理的高，与自体移植组相当。结论：复方氨基酸可以替代传统冷冻保护液中的小牛血清用于血管的深低温保存，降低了该保存技术的成本；快速深低温冷冻保存的动脉血管活力移植效果不如慢速冷冻处理的异体动脉好。     

Factors Affecting Cardiac Catheterization Rates in Elders with Acute Coronary Syndromes

Background: Elder patients with acute coronary syndromes (ACS) are less likely to receive cardiac catheterization. The reasons for this are unclear.
Objectives: To assess whether elder patients who had a documented history of dementia, lived in extended care facilities, or had do not intubate–do not resuscitate (DNR-DNI) advance directives were less likely to receive cardiac catheterization, despite having ACS with high-risk features.
Methods: This was a medical record review conducted at an urban teaching hospital. DNR-DNI status before hospitalization, extended care facility (nursing home or assisted living) residence, and a previous diagnosis of dementia were obtained from the medical record. Patients 65 years and older who presented to the emergency department with acute myocardial infarction or with unstable angina with ST segment deviation were included. Univariate and multivariate logistic regression were performed, and odds ratios (ORs) were reported with their 95% confidence intervals (CIs).
Results: Of the 201 eligible patients, 66 (32.8%) patients did not undergo cardiac catheterization. In the univariate analysis, patients who had dementia, resided in extended care facilities, or were DNR-DNI were less likely to receive cardiac catheterization. Only extended care facility residence (OR, 0.18; 95% CI = 0.04 to 0.83) and DNR-DNI status (OR, 0.19; 95% CI = 0.04 to 0.92) remained significantly associated with decreased cardiac catheterization in the multivariate analysis.
Conclusions: Elder patients with ACS residing in extended care facilities or who are DNR-DNI are less likely to receive cardiac catheterization. Future studies concerning the quality of ACS care for elders should take these variables into account.     

The J-curve relationship of treated diastolic blood pressure to mortality risk: Is it real? Is it clinically meaningful?

Low diastolic blood pressure is alleged to impose excess cardiovascular disease (CVD) risk in patients with treated hypertension, impeding aggressive reduction of blood pressure. Most investigations that assessed the potential J-shaped relations of diastolic blood pressure and adverse outcomes have not adequately considered systolic or pulse pressure in statistical analyses. An overview of hypertension trials indicates that lowering elevated blood pressure reduces the risk of CVD outcomes irrespective of the associated decrease in diastolic pressure, even if the achieved diastolic pressure averages less than 70 mm Hg. The Framingham study investigations have determined that the increased CVD incidence observed at low diastolic blood pressure levels is confined largely to persons with concomitantly increased systolic pressure. This finding of no true excess risk at low diastolic blood pressure agrees with the results of trials that have evaluated the J-curve phenomenon adjusting for systolic pressure. Aggressively treating systolic hypertension appears to produce no cause for alarm.     

Validation of Probabilistic Linkage to Match De-identified Ambulance Records to a State Trauma Registry

Objectives: To validate the accuracy of using probabilistic linkage for matching de‐identified ambulance records to a state trauma registry. Methods: This was a retrospective cohort analysis. Three thousand nine hundred nineteen true matches between ambulance and state trauma registry data from 1998 to 2003 were identified by deterministic matching on trauma identification number and verified by human review. Two thousand thirty‐eight ambulance records from trauma patients not meeting criteria for a true match, and an identical number of trauma registry records randomly selected from the one local county served by a different EMS provider, were included as nonmatches. There were 17 variables considered for linkage, which included the following: age, gender, race, county, hospital, date, rural setting, call and arrival times, mechanism, penetrating injury, vital signs, intubation, and intoxication. Probabilistic linkage was used to link the two data sets, using seven different combinations of common variables (maximum, 17; minimum, 4). The sensitivity and specificity of identifying true matches and nonmatches (95% confidence intervals [95% CI]) were calculated for each combination of variables. Results: Using all 17 available variables, 3,766 of 3,919 true matches were appropriately linked (sensitivity, 96.1%; 95% CI = 95.4% to 96.7%), with eight mismatches (specificity, 99.6%; 95% CI = 99.2% to 99.8%). Sensitivity fell below 95% with < 15 variables; however, sensitivity was very dependent on the inclusion of variables with high discriminatory power. Specificity remained >98% regardless of the number of variables included. Conclusions: Probabilistic linkage is a valid method for matching ambulance records to a trauma registry without the use of patient identifiers; however, the sensitivity of identifying true matches is critically dependent on the number and type of common variables included in the analysis.     

Comparison of Minimum Alveolar Concentration between Intravenous Isoflurane Lipid Emulsion and Inhaled Isoflurane in Dogs

Background: As in inhaled isoflurane anesthesia, when isoflurane lipid emulsion (ILE; 8%, vol/vol) is intravenously administered, the primary elimination route is through the lungs. This study was designed to determine the minimum alveolar concentration (MAC) and the time course of washout of isoflurane for intravenously infused ILE by monitoring end-tidal isoflurane concentration.

Methods: Twelve healthy adult mongrel dogs were assigned randomly to an intravenous anesthesia group with 8% ILE or to an inhalation anesthesia group with isoflurane vapor. An up-and-down method and stimulation of tail clamping were used to determine MAC of 8% ILE by intravenous injection in the intravenous anesthesia group and MAC by the inhaled approach in the inhalation anesthesia group, respectively. Isoflurane concentration and partial pressure in end-tidal gas, femoral arterial blood, and jugular venous blood were measured simultaneously just before each tail clamping and during washout.

Results: The induction time in the intravenous anesthesia group (105 +/- 24 s) was shorter than that in the inhalation anesthesia group (378 +/- 102 s; P < 0.01). MAC of 8% ILE by intravenous injection (1.12 +/- 0.18%) was significantly less than MAC by the inhaled approach (1.38 +/- 0.16%; P < 0.05). No significant difference was found between the two groups in the time course of washout of isoflurane.     

β-淀粉样蛋白和C-反应蛋白与脑血管疾病的关系

目的研究人急性脑梗死（acute cerebral infarction，ACI）、脑出血（intracerebral hemorrhage，ICH）后血清β－淀粉样蛋白（β－amyloid protein，Aβ）和C-反应蛋白（C-reactive protein，CRP）的含量变化。探讨二者与脑血管疾病发病的可能机制。方法采集急性脑梗死、脑出血患者血清标本，应用放射免疫分析法检测Aβ，免疫比浊法测定CRP，同时与正常对照组比较。结果ACI组患者Aβ（1.39±0.27）mg／ml，CRP（7.67±2.21）mg／L；ICH组Aβ（1.32±0.19）mg／ml，CRP（8.35±2.25）mg／L；正常对照组Aβ（1.05±0.17）mg／ml，CRP（2.35±1.67）mg／L。脑血管疾病组均高于正常对照组，差异有统计学意义（P〈0.05）；且Aβ和CRP之间呈正相关关系（r=0.740，P〈0.01）。结论Aβ与CRP可能是脑血管疾病发病的共同危险因素，推测两因素参与脑血管损伤导致脑血管疾病。