Volcanic eruptions contribute to climate variability, but quantifying these contributions has been limited by inconsistencies in the timing of atmospheric volcanic aerosol loading determined from ice ...cores and subsequent cooling from climate proxies such as tree rings. Here we resolve these inconsistencies and show that large eruptions in the tropics and high latitudes were primary drivers of interannual-to-decadal temperature variability in the Northern Hemisphere during the past 2,500 years. Our results are based on new records of atmospheric aerosol loading developed from high-resolution, multi-parameter measurements from an array of Greenland and Antarctic ice cores as well as distinctive age markers to constrain chronologies. Overall, cooling was proportional to the magnitude of volcanic forcing and persisted for up to ten years after some of the largest eruptive episodes. Our revised timescale more firmly implicates volcanic eruptions as catalysts in the major sixth-century pandemics, famines, and socioeconomic disruptions in Eurasia and Mesoamerica while allowing multi-millennium quantification of climate response to volcanic forcing.
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DOBA, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
We present the WD2014 chronology for the upper part (0–2850 m; 31.2 ka BP) of the West Antarctic Ice Sheet (WAIS) Divide (WD) ice core. The chronology is based on counting of annual layers observed ...in the chemical, dust and electrical conductivity records. These layers are caused by seasonal changes in the source, transport, and deposition of aerosols. The measurements were interpreted manually and with the aid of two automated methods. We validated the chronology by comparing to two high-accuracy, absolutely dated chronologies. For the Holocene, the cosmogenic isotope records of 10Be from WAIS Divide and 14C for IntCal13 demonstrated that WD2014 was consistently accurate to better than 0.5 % of the age. For the glacial period, comparisons to the Hulu Cave chronology demonstrated that WD2014 had an accuracy of better than 1 % of the age at three abrupt climate change events between 27 and 31 ka. WD2014 has consistently younger ages than Greenland ice core chronologies during most of the Holocene. For the Younger Dryas–Preboreal transition (11.595 ka; 24 years younger) and the Bølling–Allerød Warming (14.621 ka; 7 years younger), WD2014 ages are within the combined uncertainties of the timescales. Given its high accuracy, WD2014 can become a reference chronology for the Southern Hemisphere, with synchronization to other chronologies feasible using high-quality proxies of volcanism, solar activity, atmospheric mineral dust, and atmospheric methane concentrations.
Abstract Objectives To assess the need to wear compression stockings for 4 weeks after inversion stripping of the great saphenous vein (GSV) from the groin to the level of the knee. Design Randomised ...controlled trial. Patients A total of 104 consecutive patients with primary complete incompetence of the GSV treated by inversion stripping of the GSV. Methods Postoperatively treated limbs underwent elastic bandaging for 3 days. Volunteers were randomised to wear a compression stocking for additional 4 weeks (intervention group) or no compression stocking (control group). The primary outcome was limb oedema as assessed by photoelectric leg volume measurement. Secondary outcome measures were pain scores, postoperative complications and return to full work. Results The control leg volume was 3657 ml (standard deviation, SD 687) preoperatively and 3640 ml (SD 540) 4 weeks postoperatively (non significant, N.S.). The stocking leg volume was 3629 ml (SD 540) preoperatively, falling to 3534 ml (SD 543) ( P < 0.01) 4 weeks postoperatively. The difference in leg volume between both the groups was not statistically significant. Patients in the control group resumed work earlier (control 11 days, stocking 15 days, P = 0.02, Mann–Whitney test). No difference was observed in the number and type of complication and in pain scores during the 4-week follow-up period. Conclusions Wearing an elastic compression stocking has no additional benefit following elastic bandaging for 3 days in postoperative care after stripping of the great saphenous vein as assessed by control of limb oedema, pain, complications and return to work.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract Objectives The Walking Impairment Questionnaire (WIQ) is a frequently used questionnaire to evaluate patients with intermittent claudication (IC). The aim of this study is to validate the ...Dutch WIQ for the European situation using the metric system. Design Validation study. Materials After translation and cultural adaptation of the WIQ, 130 patients with IC completed the Dutch WIQ, the RAND-36, and the EuroQol questionnaire. Walking distances were determined by treadmill testing. Methods Correlations between the WIQ, the two quality of life questionnaires, and walking distances were calculated to determine validity. Reliability and internal consistency were determined using the intraclass correlation coefficient (ICC) and Cronbach's alpha, respectively. Results Significant correlations were found between the WIQ and the absolute claudication distance (ACD) (0.52), EuroQol (0.33) and seven domains of the RAND-36. Test–retest reliability expressed by the ICC was 0.89. The internal consistency determined by Cronbach's alpha was 0.92 for the total WIQ score. Furthermore, a lower WIQ score corresponds to a shorter ACD. Conclusions This study shows that the Dutch version of the WIQ using the European metric system is a valid, reliable and clinically relevant instrument for assessing walking impairment in patients with intermittent claudication.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
OBJECTIVE:The aim of this was to analyze differences between saccular-shaped abdominal aortic aneurysms (SaAAAs) and fusiform abdominal aortic aneurysms (FuAAAs) regarding patient characteristics, ...treatment, and outcome, to advise a threshold for intervention for SaAAAs.
BACKGROUND:Based on the assumption that SaAAAs are more prone to rupture, guidelines suggest early elective treatment. However, little is known about the natural history of SaAAAs and the threshold for intervention is not substantiated.
METHODS:Observational study including primary repairs of degenerative AAAs in the Netherlands between 2016 and 2018 in which the shape was registered, registered in the Dutch Surgical Aneurysm Audit (DSAA). Patients were stratified by urgency of surgery; elective versus acute (symptomatic/ruptured). Patient characteristics, treatment, and outcome were compared between SaAAAs and FuAAAs.
RESULTS:A total of 7659 primary AAA-patients were included, 6.1% (n = 471) SaAAAs and 93.9% (n = 7188) FuAAAs. There were 5945 elective patients (6.5% SaAAA) and 1714 acute (4.8% SaAAA). Acute SaAAA-patients were more often female (28.9% vs 17.2%, P = 0.007) compared with acute FuAAA-patients. SaAAAs had smaller diameters than FuAAAs, in elective (53.0 mm vs 61 mm, P = 0.000) and acute (68 mm vs 75 mm, P = 0.002) patients, even after adjusting for sex. In addition, 25.2% of acute SaAAA-patients presented with diameters <55 mm and 8.4% <45 mm, versus 8.1% and 0.6% of acute FuAAA-patients (P = 0.000). Postoperative outcomes did not significantly differ between shapes in both elective and acute patients.
CONCLUSIONS:SaAAAs become acute at smaller diameters than FuAAAs in DSAA patients. This study therefore supports the current idea that SaAAAs should be electively treated at smaller diameters than FuAAAs. The exact diameter threshold for elective treatment of SaAAAs is difficult to determine, but a diameter of 45 mm seems to be an acceptable threshold.
Abstract Objective The aim of the study was evaluating the diagnostic value of plasma matrix metalloproteinase- (MMP)-2 and -9 and tissue inhibitor of MMP-1 (TIMP-1) for endoleak detection after ...endovascular aneurysm repair (EVAR). Report Consecutive EVAR patients ( n = 17) with endoleak and matched controls without endoleak ( n = 20) were prospectively enrolled. Increased levels of MMP-9 were observed in patients with endoleak ( P < 0.001). Regression analysis showed no significant influence of age, sex or abdominal aortic aneurysm (AAA) size. The receiver operating characteristic (ROC) curve of plasma MMP-9 levels showed that a cut-off value of 55.18 ng ml−1 resulted in 100% sensitivity and 96% specificity with an AUC value of 0.988 ( P < 0.001) to detect endoleak. Conclusions Plasma MMP-9 levels appear to discriminate between patients with and without an endoleak with high sensitivity and specificity.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Background Chronic renal insufficiency (CRI) is a growing global problem. PTA can be performed without nephrotoxic contrast, utilizing Doppler-ultrasound (Duplex) guidance. Duplex-guided ...infra-inguinal interventions and access-related interventions have been reported. Duplex-guided iliac interventions have not been performed to any extent because of the anatomic location. In our study we evaluated the safety and efficacy of Duplex-guided percutaneous transluminal angioplasty (DuPTA) in iliac arteries. Methods From June 2012 until February 2013, 31 patients (35 iliac lesions), underwent DuPTA. Indications ranged from Rutherford 3 to 5. Preoperative evaluation included Ankle Brachial Index (ABI), Duplex and MRA. Procedural success was defined as crossing the lesion with a guidewire and dilating or stenting the lesion. Clinical success was defined as 50% reduction in peak systolic velocity (PSV) or clinical improvement. PSV was evaluated after PTA, then at 2 weeks. Clinical results were assessed 2 weeks after the procedure. Results Procedural success was achieved in 94% of patients (33/35), all of whom also had clinical success. Post-procedural PSV reduction showed an average improvement of 63% (431 cm/s to 153 cm/s). Mean preoperative ABI was 0.72 and improved to 0.88 postoperatively. Conclusions PTA using Duplex-guidance in significant iliac stenosis is a safe method with major advantages in patients at high risk for developing contrast-induced nephropathy.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Background. Long-term peritoneal dialysis (PD) is associated with the development of functional and structural alterations of the peritoneal membrane. In this study, we investigated the contribution ...of low pH lactate buffer, high glucose concentration and glucose degradation products to peritoneal injury in a rat peritoneal exposure model. Methods. Rats received daily 10 ml of either heat-sterilized (3.86% glucose, pH 5.2, n = 8) or filter-sterilized PD fluid (3.86% glucose, pH 5.2, n = 8), or lactate buffer (pH 5.2, n = 8) via a mini vascular access port during a 10 week period. Untreated rats served as controls. Results. The low pH lactate buffer instillation induced pronounced morphological changes including the induction of angiogenesis in various peritoneal tissues and mild damage to the mesothelial cell layer covering the peritoneum. It also evoked a cellular response characterized by an increased mesothelial cell density on the liver, the induction of milky spots and accumulation of omental mast cells in the omentum, and significant changes in the composition of peritoneal leukocytes. The addition of glucose to low pH lactate buffer (filter-sterilized PD fluid) strengthened most, but not all of the responses described above and induced a fibrogenic response. In addition to glucose and low pH lactate buffer, the presence of glucose degradation products (heat-sterilized PD fluid) significantly induced an additional omental milky spot response (P < 0.03) and caused profound mesothelial damage. The vessel density in the omentum and the mesentery was significantly correlated to both the number of tissue mast cells and the hyaluronan content in the peritoneal lavage, which might suggest a role for mast cells and hyaluronan in the induction of angiogenesis. Conclusions. Instillations of low pH lactate buffer, a high glucose concentration and glucose degradation products contribute differently and often cumulatively to peritoneal injury in vivo.
Introduction and Methods: The most frequent complication of polytetrafluoroethylene (PTFE) arteriovenous grafts for hemodialysis is thrombotic occlusion due to stenosis caused by intimal hyperplasia. ...This complication is also known for peripheral bypass grafts. Because the use of a venous cuff at the distal anastomosis improves the patency of peripheral bypass grafts, we considered that it might also improve the patency of PTFE arteriovenous grafts. Therefore, a randomized multicenter trial was carried out to study the effect of a venous cuff at the venous anastomosis of PTFE arteriovenous grafts on the development of stenoses and the patency rates. Results: Of the 120 included patients, 59 were randomized for a venous cuff. The incidence of thrombotic occlusion was lower in the cuff group (0.68 per patient-year) than in the no-cuff group (0.88 per patient-year; P =.0007). However, the primary and secondary patency rates were comparable. The cuff group tended to have fewer stenoses at the venous and arterial anastomoses when examined with duplex scan. Graft failure was higher in patients with an initial anastomosing vein diameter smaller than 4 mm (7 of 18 39%) than in those with a vein diameter of 4 mm or larger (16 of 88 18%; P =.052). Local edema, skin atrophy, and obesity yielded a higher risk on graft failure (23% vs 11%). Conclusion: A venous cuff at the venous anastomosis of PTFE arteriovenous grafts for hemodialysis reduced the incidence of thrombotic occlusions; stenosis at the venous anastomosis was reduced. However, this did not result in a better patency rate. Therefore, the venous cuff should not be used routinely. Initial vein diameter and local problems (edema, obesity, or skin atrophy) appear to be the most important risk factors for graft failure. (J Vasc Surg 2000;32:1155-63.)
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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