Clinics in diagnostic imaging (162). Meckel’s diverticulum

A 28-year-old Chinese man presented with acute bleeding per rectum. Computed tomography showed a posterior outpouching arising from the distal ileum. The outpouching had hyperaemic walls, but no active contrast extravasation was detected. Technetium-99m pertechnetate scintigraphy showed focal areas of abnormal uptake in the right side of the pelvis, superior and posterior to the urinary bladder. These areas of uptake appeared simultaneously with the gastric uptake and demonstrated gradual increase in intensity on subsequent images. The diagnosis of Meckel’s diverticulum was confirmed on surgery and the lesion was resected. The clinical and imaging features of Meckel’s diverticulum are discussed.     

Effective and Safe Anesthesia for Yorkshire and Yucatan Swine with and without Cardiovascular Injury and Intervention

The goal of this study was to identify an injectable anesthetic protocol that provides sedation sufficient for peripheral vascular catheterization, intubation, and transport while minimizing cardiovascular changes in Yorkshire and Yucatan pigs with and without cardiovascular injury and intervention (CI). Phase 1 examined the safety and efficacy of acepromazine–ketamine, diazepam–ketamine, midazolam–ketamine, and medetomidine–ketamine in 5 healthy Yorkshire pigs. For each drug combination, we obtained multiple measurements of heart rate, blood pressure, respiratory rate, temperature, sedation score, ability to catheterize and intubate, and recovery score. Phase 2 evaluated and refined the dose of the most effective Phase 1 anesthetic combination (midazolam–ketamine) in healthy and CI Yorkshire pigs (n = 53 trials). Phase 3 mirrored Phase 2 but tested midazolam–ketamine in healthy and CI Yucatan pigs (n = 34 trials). Midazolam (0.5 mg/kg)–ketamine (25 to 27 mg/kg) was the most effective anesthetic combination in healthy Yorkshire pigs, but this dose was less effective in healthy Yucatan pigs and CI Yorkshire and Yucatan pigs. Midazolam–ketamine resulted in tachycardia and apnea more frequently in CI pigs than healthy pigs. This combination also caused vomiting in one CI Yucatan pig. Overall, midazolam–ketamine provided safe and effective sedation for catheterization and intubation of both healthy and CI pigs. This study suggests Yucatan pigs may require a higher dose midazolam–ketamine to achieve the same level of sedation as that in Yorkshire pigs. Although anesthetic complication rates were higher in CI pigs, our results indicate that midazolam–ketamine can be safely used for sedation of both pig breeds with and without CI.Abbreviation: CI, cardiovascular injury and interventionPigs (Sus scrofa) are common models of cardiovascular injury and intervention (CI) that largely have replaced traditional canine cardiology models. Advantages of swine compared with dogs include anatomic and physiologic characteristics similar to humans, such as similar coronary artery distribution and effective collateralized blood flow to the myocardium after coronary artery blockage.²³ However, pigs are difficult to restrain and anesthetize due to their size and resistance to sedative drug combinations, including those with morphine.²⁴ Injectable sedative drugs may result in cardiovascular and respiratory effects such as increased cardiac work and oxygen consumption, tachycardia, bradycardia, apnea, hypertension, and hypotension.^{5,6,8-12,14,19,20,25-29} These side effects can pose considerable problems for CI pigs, and anesthesia protocols with minimal effects on cardiovascular function are needed. A literature review revealed no published studies of anesthetic protocols in swine with existing cardiovascular injury; published research is limited to investigating anesthesia protocols for experimental induction of CI or determining in vitro and in vivo drug effects on healthy cardiovascular systems.^{4-6,8-12,14,19-21,25-29} Other published studies have limited investigations to studying sedative and physiologic effects in healthy Yorkshire, Yucatan, mixed-breed, Landrace, and Gottingen miniature swine.^{2,3,10,13,17,18,20-22}We conducted the current study to address the need for a systematic investigation of anesthetic protocols in CI Yorkshire and Yucatan pigs. The goals of this study were to determine an injectable-only anesthetic protocol for both Yorkshire and Yucatan pigs that yielded sufficient sedation for peripheral vascular catheterization, sufficient duration for transport, and minimal cardiovascular effects while being safe and effective for CI pigs.     

颈椎椎后肌肉组织中肌膜Na^＋-K^＋-ATP酶活性与颈椎病

目的:探讨颈椎椎后肌肉组织Na -K -ATP酶活性变化与颈椎病的关系。资料来源:应用计算机检索PubMed1988-01/2004-12相关骨骼肌损伤与肌组织Na -K -ATP酶关系的文献,检索词“Na -K pump,Na -K -ATPase,muscle”,限定文献语言种类为English。同时计算机检索CNKI1990-01/2005-12相关Na -K -ATP酶与骨骼肌损伤的关系及颈椎病发病病因的文献,检索词“Na -K -ATP酶,骨骼肌,颈椎病病因”,限定文献语言种类为中文。资料选择:对资料进行初审,选取包括Na -K -ATP酶与肌组织损伤关系的文献,开始查找全文。纳入标准:Na -K -ATP酶活性变化与骨骼肌损伤密切相关的文献研究。排除标准:重复研究,Meta分析类文章。资料提炼:共检索到939篇关于Na -K -ATP酶与骨骼肌损伤相关方面的文献,最终纳入20篇符合标准的文献。资料综合:众多研究表明,Na 、K 与骨骼肌的兴奋、收缩、疲劳有密切关系,而Na -K -ATP酶又是调节细胞内外Na 、K 浓度必不可少的高分子蛋白,也就是说,骨骼肌一系列活动均离不开Na -K -ATP酶,Na -K -ATP酶活性变化与骨骼肌损伤是相互影响的。而强迫屈颈体位作为颈椎病发病的危险因素之一,可使颈椎椎后肌肉Na -K -ATP酶活性降低,酶活性降低致使肌细胞损伤,并最终导致骨骼肌损伤而发病。结论:以颈椎椎后肌肉酶活性的变化来阐释中医药对颈椎病确切疗效的相关研究未见,这有待于进一步研究,以充分展示中医药在颈椎病等相关疾病中的治疗优势。     

猪胸腰段脊髓火器贯通伤后p53基因的早期表达

目的:建立家猪胸腰段脊髓火器贯通伤模型和改良Allen's打击伤后全瘫模型,观察伤后促凋亡基因p53基因的早期表达。方法:实验于2005-05/08在解放军第一七五医院实验室完成。取健康雄性家猪20只,单纯随机分为3组:①火器伤组:9只,在全麻状态下制作胸腰段(L1～L2)脊髓火器伤模型,分为伤后1,3,6h3个时间处死。②打击伤组:9只,L1节段脊髓行改良Allen’s打击,致伤力为500g·cm,处死时间同前。③空白对照组:2只,只麻醉,不造模,伤后6h处死。伤后不同时间点(伤后1,3,6h)和不同节段(伤点、近伤点、中伤点及远伤点)取材,采用SP法进行P53蛋白免疫组化染色,用TJTY-300型全自动图像分析仪测量P53免疫组织化学染色阳性物质吸光度。结果:经补充后20只猪进入结果分析。①脊髓损伤后3h打击伤组伤点,火器伤组近伤段脊髓P53蛋白的表达高于空白对照组(P<0.001),随着时间推移,打击伤组和火器伤组P53蛋白的表达呈升高趋势(P<0.001),且火器伤组要高于打击伤组(P<0.0001)。②在脊髓损伤后6h,打击伤组仅在伤点和近伤段P53蛋白的表达高于空白对照组(5.57±0.82,3.21±0.43,P<0.05),而火器伤组近伤段、中伤段及远段伤均高于空白对照组(6.46±0.66,4.27±0.39,1.16±0.17,P<0.05)。结论:①细胞凋亡基因p53在脊髓损伤中的表达有一定的时空性,在脊髓损伤后3h出现P53蛋白表达量的增加。②脊髓火器伤的波及范围较打击伤更为广泛。     

An empirical model of the Baltic Sea reveals the importance of social dynamics for ecological regime shifts

Regime shifts triggered by human activities and environmental changes have led to significant ecological and socioeconomic consequences in marine and terrestrial ecosystems worldwide. Ecological processes and feedbacks associated with regime shifts have received considerable attention, but human individual and collective behavior is rarely treated as an integrated component of such shifts. Here, we used generalized modeling to develop a coupled social–ecological model that integrated rich social and ecological data to investigate the role of social dynamics in the 1980s Baltic Sea cod boom and collapse. We showed that psychological, economic, and regulatory aspects of fisher decision making, in addition to ecological interactions, contributed both to the temporary persistence of the cod boom and to its subsequent collapse. These features of the social–ecological system also would have limited the effectiveness of stronger fishery regulations. Our results provide quantitative, empirical evidence that incorporating social dynamics into models of natural resources is critical for understanding how resources can be managed sustainably. We also show that generalized modeling, which is well-suited to collaborative model development and does not require detailed specification of causal relationships between system variables, can help tackle the complexities involved in creating and analyzing social–ecological models.In recent decades, the world’s biological and physical systems have experienced dramatic change (1, 2). Many marine ecosystems, for example, have undergone abrupt changes known as regime shifts (3, 4). In one prominent case, the Baltic cod fishery suddenly changed in the 1980s from historically high cod biomass and catches (henceforth the “cod boom”) to a sprat-dominant ecosystem with low cod abundance (5–8). This collapse, generally understood to have been precipitated by deteriorating environmental conditions and overfishing (7), had substantial negative socioeconomic impact on Baltic Sea fisheries, including among others the small-scale coastal fishery (9).Ecological analyses of regime shifts, such as of the Baltic cod fishery (10), can capture the complex interplay of ecological and physical processes and drivers that trigger the shift. Numerous studies, however, have shown that understanding individual and collective human behavior is also critical for managing natural resources (11, 12) such as marine ecosystems (13, 14). Social–ecological system research responds to the need to incorporate humans as part of ecosystems by treating natural resource use as arising from linked systems of humans and nature, so-called social–ecological systems. Social–ecological system dynamics result from feedback loops involving biophysical processes, human behavior, and institutional processes within given social and biophysical contexts (15). Formal, quantitative analyses of the contributions of the social and biophysical subsystems to a social–ecological system’s dynamics are rare, however, because knowledge of social–ecological systems is often partial and spread over multiple disciplines (16).Here, we tested the influence of social dynamics on a regime shift in a marine ecosystem using a formal modeling framework. Specifically, we investigated the significance of fisher decision making, as influenced by psychological, economic, and regulatory factors, on the 1980s boom and collapse of the Eastern Baltic cod stock. In a significant advance for natural resource modeling, and for social–ecological modeling more generally, use of the generalized modeling approach (17, 18) enabled us to empirically parameterize, dynamically model, and analyze the qualitative social and ecological dynamics of the Baltic cod fishery at comparable levels of detail and without detailed specification of causal relationships. The Baltic cod fishery was selected because the ecological dynamics during the cod boom and collapse have been well-studied (10, 19, 20), and information about fisher behavior and institutional settings, such as regulation and subsidy policy, is available. Additionally, the cod boom and collapse are qualitatively distinct features of the social–ecological system’s dynamics that are amenable to the concepts and methods of dynamical systems theory (21), such as stability.     

Accuracy of supplementary serologic testing for human T-lymphotropic virus types I and II in US blood donors. Retrovirus Epidemiology Donor Study

Blood donations in the United States have been screened for antibody to human T-lymphotropic virus type I (HTLV-I) by HTLV-I enzyme immunoassay (EIA) since November 1988. Specimens repeatedly found to be reactive by EIA undergo confirmation by supplementary serologic tests. We assessed the accuracy of blood center testing of 994 HTLV-I EIA repeat-reactive specimens in five US blood centers between November 1988 and December 1991. Of 410 confirmed HTLV-I/II donations, 407 (99.3%) were infected with HTLV-I/II, as determined by polymerase chain reaction (PCR) (403 cases) and by repeat serologic testing (4 cases). The three false- positive results occurred in the first year of testing. Of 425 HTLV- indeterminate specimens, 6 (1.4%) were found to be infected by PCR (5 with HTLV-II and 1 with HTLV-I). None of 159 confirmatory test-negative donations was PCR positive. Of HTLV-I/II-seropositive specimens, 80.2% to 95.4% could be typed as HTLV-I or HTLV-II by type-specific serologic assays. These results support recommendations that HTLV-I/II- seropositive donors should be advised that they are infected with HTLV- I, HTLV-II, or HTLV-I/II (depending on results of type-specific assays). HTLV-indeterminate donors should be advised that their results only rarely indicate HTLV infection. HTLV confirmatory test-negative donors should be reassured that they are not infected with HTLV-I or HTLV-II.