Ischemia/reperfusion injury in rat mesenteric venules: red blood cell velocity and leukocyte rolling.

Ischemia/reperfusion injury in rat mesenteric venules: red blood cell velocity and leukocyte rolling. Beuk RJ, oude Egbrink MG, Kurvers HA, Bonke HJ, Tangelder GJ, Heineman E. Department of Surgery, University Hospital Maastricht, The Netherlands. The authors determined the effects of 15 (n = 9) and 30 (n = 12) minutes of warm ischemia on the rat mesentery and compared the results with those of a sham-operated group (n = 10). Red blood cell velocity and number of rolling leukocytes were assessed before ischemia as well as 10, 20, 30, 60, 90, and 120 minutes after the start of reperfusion. Leukocyte rolling is considered to be an early step of the inflammatory process. Leukocytes roll along the vessel wall at a velocity that is clearly lower than that of the other blood cells. The preischemic values of red blood cell velocity and number of rolling leukocytes in the 15- and 30-minute ischemia groups did not differ from those of the sham group. In the sham group, no significant changes in red blood cell velocity and number of rolling leukocytes were observed over time. Compared with the sham group, the red blood cell velocity of the 15-minute ischemia group was significantly lower at 30, 60, 90, and 120 minutes after the start of reperfusion the number of rolling leukocytes did not differ significantly. For the 30-minute ischemia group, red blood cell velocity also was significantly lower at 20, 30, 60, 90, and 120 minutes after the start of reperfusion, and the number of rolling leukocytes was higher at 10, 20, and 30 minutes after the start of reperfusion. The results of this study indicate that short periods of total warm ischemia of the rat small bowel and subsequent reperfusion result in a significantly impaired microcirculatory blood flow in the mesentery. However, a prolonged period of ischemia is required to increase leukocyte-vessel wall interactions. In the future, this model will enable us to study the effect of pharmacological interventions during an early stage of the inflammatory response to ischemia/reperfusion in the gut

Leucocyte and platelet adhesion in different layers of the small bowel during experimental total warm ischaemia and reperfusion

BACKGROUND: Ischaemia and reperfusion (IR) of the small bowel is involved in many clinical conditions. A key component in IR-induced tissue damage is microvascular dysfunction. The aim was to investigate the role of leucocytes and platelets in capillary flow impediment and tissue damage. METHODS: Anaesthetized rats were subjected to 30 min warm ischaemia of the small bowel, followed by 1 h reperfusion. To elucidate the influence of leucocytes on platelet adhesion, leucocyte-vessel wall interactions induced by IR were prevented by anti-platelet activating factor (PAF) or anti-intercellular adhesion molecule (ICAM)-1. Intravital videomicroscopy was performed and tissue injury was evaluated histologically. RESULTS: In submucosal venules, IR induced an increase in the median number of interacting leucocytes from 3 to 10 and 20 leucocytes per 100-microm venule segment after 10 and 60 min reperfusion respectively. Anti-PAF or anti-ICAM-1 completely attenuated this increase, resulting in an eightfold improvement in submucosal capillary flow and reduced tissue injury. Shedding of villi no longer occurred. Platelet-vessel wall interactions occurred particularly in submucosal venules, but were not affected by anti-PAF or anti-ICAM-1. CONCLUSION: Small bowel IR initiated an inflammatory and thrombotic response in the submucosal layer only. Attenuation of leucocyte adhesion improved submucosal capillary perfusion, preventing shedding of mucosal villi

Culture results from wound biopsy versus wound swab: does it matter for the assessment of wound infection?

Objectives: The aim of this study was to determine whether assessment of wound infection differs when culture results from wound biopsy versus wound swab are available in clinical practice. Methods: For 180 eligible patients, a swab and biopsy were taken from one wound during a regular appointment at a wound care facility in eastern Netherlands. Culture results from both methods were supplemented with clinical information and provided to a panel of six experts who independently assessed each wound as infect or not, separately for swab and biopsy. Assessments for biopsy and swab were compared for the complete expert panel, and for individual experts. Results: The complete expert panel provided the same wound assessment based on (clinical information and) culture results from wound biopsy and wound swab in 158 of 180 wounds (87.8%, kappa 0.67). For individual experts, agreement between biopsy and swab varied between 77% and 96%. However, there were substantial differences between experts: the same assessment was provided in 62 (34.4%) to 76 (42.2%) wounds for swab and biopsy respectively. Conclusions: Assessment of infection does not significantly differ when culture results from swabs or biopsies are available. The substantial variability between individual experts indicates non-uniformity in the way wounds are assessed. This complicates accurate detection of infection and comparability between studies using assessment of infection as reference standard

Saccular Abdominal Aortic Aneurysms Patient Characteristics, Clinical Presentation, Treatment, and Outcomes in the Netherlands

Objective: The aim of this was to analyze differences between saccularshaped 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 SaAAApatients 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 (53.0mm vs 61 mm, P = 0.000) and acute (68mm vs 75 mm, P = 0.002) patients, even after adjusting for sex. In addition, 25.2% of acute SaAAA-patients presented with diameters <55mm 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 45mm seems to be an acceptable threshold.Vascular Surger