37 research outputs found

    Assessing the risk of bluetongue to UK livestock: uncertainty and sensitivity analyses of a temperature-dependent model for the basic reproduction number

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    Since 1998 bluetongue virus (BTV), which causes bluetongue, a non-contagious, insect-borne infectious disease of ruminants, has expanded northwards in Europe in an unprecedented series of incursions, suggesting that there is a risk to the large and valuable British livestock industry. The basic reproduction number, R0, provides a powerful tool with which to assess the level of risk posed by a disease. In this paper, we compute R0 for BTV in a population comprising two host species, cattle and sheep. Estimates for each parameter which influences R0 were obtained from the published literature, using those applicable to the UK situation wherever possible. Moreover, explicit temperature dependence was included for those parameters for which it had been quantified. Uncertainty and sensitivity analyses based on Latin hypercube sampling and partial rank correlation coefficients identified temperature, the probability of transmission from host to vector and the vector to host ratio as being most important in determining the magnitude of R0. The importance of temperature reflects the fact that it influences many processes involved in the transmission of BTV and, in particular, the biting rate, the extrinsic incubation period and the vector mortality rate

    Cocaine-related aortic dissection : lessons from the international registry of acute aortic dissection

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    Background Acute aortic dissection associated with cocaine use is rare and has been reported predominantly as single cases or in small patient cohorts.Methods Our study analyzed 3584 patients enrolled in the International Registry of Acute Aortic Dissection from 1996 to 2012. We divided the population on the basis of documented cocaine use (C+) versus noncocaine use (C-) and further stratified the cohorts into type A (33 C+/2332, 1.4%) and type B (30 C+/1252, 2.4%) dissection.Results C+ patients presented at a younger age and were more likely to be male and black. Type B dissections were more common among C+ patients than in C- patients. Cocaine-related acute aortic dissection was reported more often at US sites than at European sites (86.4%, 51/63 vs 13.6%, 8/63; P <.001). Tobacco use was more prevalent in the C+ cohort. No differences were seen in history of hypertension, known atherosclerosis, or time from symptom onset to presentation. Type B C+ patients were more likely to be hypertensive at presentation. C+ patients had significantly smaller ascending aortic diameters at presentation. Acute renal failure was more common in type A C+ patients; however, mortality was significantly lower in type A C+ patients.Conclusions Cocaine use is implicated in 1.8% of patients with acute aortic dissection. The typical patient is relatively young and has the additional risk factors of hypertension and tobacco use. In-hospital mortality for those with cocaine-related type A dissection is lower than for those with noncocaine-related dissection, likely due to the younger age at presentation

    Interaction between refractories and basic slags during the vacuum treatment of steel

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    Translated from Russian (Stal' 1986 (3) p. 41-42)SIGLEAvailable from British Library Document Supply Centre- DSC:5828.4(M--36879)T / BLDSC - British Library Document Supply CentreGBUnited Kingdo

    The role of age in complicated acute type B aortic dissection

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    Background Complicated acute type B aortic dissection (cABAD) generally requires urgent intervention. Advanced age is a risk factor for mortality after thoracic aortic intervention, including surgery for aortic dissection. The purpose of this study was to investigate the exact impact of increasing age on the management and outcomes of cABAD. Methods We analyzed the outcomes of 583 patients with cABAD enrolled in the International Registry of Acute Aortic Dissection (IRAD) between 1996 and 2012. All patients with cABAD were categorized according to age by decade and management type (medical, surgical, or endovascular treatment), and outcomes were subsequently investigated in the different age groups. Results The mean age of the cohort was 63.4 \ub1 14.2 years, 36% of patients (n = 209) were greater than 70 years of age and 64% (n = 374) were less than 70 years. The utilization of surgery and endovascular techniques progressively decreased with patient age, while the rate of medical management significantly increased with age (p < 0.001). The in-hospital mortality rates for complicated patients younger than 70 years versus 70 years or more were 10.1% versus 30.0% for endovascular treatment (p = 0.001), 17.2% versus 34.2% for surgical treatment (p = 0.027), and 14.2% versus 32.2% for medical treatment (p = 0.001). Age 70 years or greater was a predictor of in-hospital mortality in multivariate analysis (odds ratio 2.37, 95% confidence interval: 1.23 to 4.54, p = 0.010). Conclusions Advanced age has a dramatic impact on the management and outcomes of patients with cABAD. A nonsignificant trend toward lower mortality after endovascular management was observed, both for younger patients and for elderly patients

    Shock complicating type A acute aortic dissection: clinical correlates, management, and outcomes

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    Aims Shock is among the most dreaded and common complications of type A acute aortic dissection (TAAAD). However, clinical correlates, management, and short- and long-term outcomes of TAAAD patients presenting with shock in real-world clinical practice are not known. Methods and Results We evaluated 2,704 patients with TAAAD enrolled in the International Registry of Acute Aortic Dissection between January 1, 1996, and August 18, 2012. On admission, 407 (15.1%) TAAAD patients presented with shock. Most in-hospital complications (coma, myocardial or mesenteric ischemia or infarction, and cardiac tamponade) were more frequent in shock patients. In-hospital mortality was significantly higher in TAAAD patients with than without shock (30.2% vs 23.9%, P =.007), regardless of surgical or medical treatment. Most shock patients underwent surgical repair, with medically managed patients demonstrating older age and more complications at presentation. Estimates using Kaplan-Meier survival analysis indicated that most (89%) TAAAD patients with shock discharged alive from the hospital survived 5 years, a rate similar to that of TAAAD patients without shock (82%, P =.609). Conclusions Shock occurred in 1 of 7 TAAAD patients and was associated with higher rates of in-hospital adverse events and mortality. However, TAAAD survivors with or without shock showed similar long-term mortality. Successful early and aggressive management of shock in TAAAD patients has the potential for improving long-term survival in this patient population

    Acute type B aortic dissection complicated by visceral ischemia

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    Objective Acute type B aortic dissection (ABAD) can lead to visceral malperfusion, a potentially life-threatening complication. The purpose of this study was to investigate the presentation, management, and outcomes of ABAD patients with visceral ischemia who are enrolled in the International Registry of Acute Aortic Dissection. Methods Patients with ABAD enrolled in the registry between 1996 and 2013 were identified and stratified based on presence of visceral ischemia at admission. Demographics, medical history, imaging results, management, and outcomes were compared for patients with versus without visceral ischemia. Results A total of 1456 ABAD patients were identified, of which 104 (7.1%) presented with visceral ischemia. Preoperative limb ischemia (28% vs 7%, P <.001) and acute renal failure (41% vs 14%, P <.001) were more common among patients with visceral ischemia. Endovascular treatment and surgery were offered to 49% and 30% of the visceral ischemia cohort, respectively; remaining patients were managed conservatively. The in-hospital mortality was 30.8% for patients with visceral ischemia and 9.1% for those without visceral ischemia (odds ratio [OR] 4.44; 95% confidence interval [CI], 2.8-7.0, P <.0001). Mortality rates were similar after surgical and endovascular management of visceral ischemia (25.8% and 25.5%, respectively, P = not significant). Among the visceral ischemia group, medical management was a predictor of mortality in multivariate analysis (OR, 5.91; 95% CI, 1.2-31.0; P =.036). Conclusions Patients with ABAD complicated by visceral ischemia have a high risk of mortality. We observed similar outcomes for patients treated by endovascular management versus surgery, whereas medical management was an independent predictor of mortality. Early diagnosis and intervention for visceral ischemia seems to be crucial
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