Histological interpretation of temporal artery biopsies

Temporal artery biopsy is recommended for diagnosis of suspected giant cell arteritis, a systemic vasculitis of older adults. There is currently no formal consensus for histological interpretation of the biopsies. Typical histological findings include a transmural lymphocytic infiltrate with a population of macrophages resulting in destruction of the internal elastic lamina. However, it is a patchy process and multiple tissue levels must be examined. It is important to be aware of various subtle features that may lead to a diagnosis of arteritis, and immunohistochemistry can be helpful in some cases. Some biopsies show unusual features that could raise a differential diagnosis of alternative vasculitides. When there is no evidence of arteritis in a specimen, there are often non-specific features seen in the context of age-related changes. All of these histological patterns require close clinicopathological correlation to ensure correct interpretation.     

高流体静力压和缺氧对大隐静脉和脾静脉滋养血管超微结构的影响

目的观察大隐静脉和脾静脉滋养血管内皮细胞超微结构变化,探讨高流体静力压和缺氧对滋养血管内皮细胞的影响。方法收集曲张大隐静脉和高压性脾静脉管壁标本34例,另设对照组为正常大隐静脉和脾静脉34例。采用HE染色光镜下观察大隐静脉和脾静脉外膜层滋养血管,半薄切片定位。再采用超薄切片,透射电镜下观察滋养血管内皮细胞的超微结构变化。结果大隐静脉曲张组和病脾静脉组滋养血管内皮细胞细胞核结构完整,染色质分布正常;部分线粒体基质深染,嵴模糊、嵴断裂。结论高流体静力压和缺氧下大隐静脉和脾静脉管壁滋养血管内皮细胞的超微结构会出现重塑现象,二者改变相同。     

Diabetes mellitus prevents capsaicin from inducing hyperaemia in the rat sciatic nerve

Summary Loss of neurogenic inflammation in response to tissue injury may be an important complication of diabetes mellitus. We studied local neurogenic inflammation in the peripheral nerve trunk of Sprague-Dawley rats 4 months following the induction of diabetes by streptozotocin injection. To assess neurogenic inflammation, the epineurial plexus of the sciatic nerve was exposed to topical capsaicin, an agent that releases vasoactive neuropeptides from perivascular afferent terminals. Under normal circumstances, local vasodilatation results in endoneurial hyperaemia or a ‘flare’. We evaluated the influence of capsaicin in diabetic sciatic nerve by making serial measurements of endoneurial blood flow using microelectrodes sensitive to hydrogen clearance. After 4 months of hyperglycaemia (glucose >16.0 mmol/l), diabetic animals had slowing of unmyelinated and myelinated sural sensory conduction velocity compared to citrate buffer injected controls. Baseline sciatic endoneurial blood flow was unaltered by diabetes, and was comparable to controls. There was an expected hyperaemic response of endoneurial blood flow to capsaicin in control rat sciatic endoneurium but no consistent ‘flare’ response in diabetic rats. Our findings indicate that there is loss of capsaicin-related neurogenic inflammation in the vasa nervorum of experimental diabetes. It is possible that a similar deficit following nerve injury could impair the milieu for axonal regeneration in diabetes.     

Automatic Methods for Carotid Contrast-Enhanced Ultrasound Imaging Quantification of Adventitial Vasa Vasorum

Adventitial vasa vasorum are physiologic microvessels that nourish artery walls. In the presence of cardiovascular risk factors, these microvessels proliferate abnormally. Studies have reported that they are the first stage of atheromatous disease. Contrast-enhanced ultrasound (CEUS) of the carotid allows direct, quantitative and non-invasive visualization of the adventitial vasa vasorum. Hence, the development of computer-assisted methods that speed image analysis and eliminate user subjectivity is important. We developed methods for automatic analyses and quantification of vasa vasorum neovascularization in CEUS and tested these methods in a cohort of 186 individuals, 63 of whom were healthy volunteers. We implemented alternative automatic strategies for using the images to stratify patients according to their risk group and compare the strategies with respect to diagnostic performance. An automatic single-parameter strategy performs less effectively than the corresponding Arcidiacono method based on manual interpretation of the images (68 < area under the receiver operating characteristic curve [AUROC] for the manual Arcidiacono method < 82; 60 < AUROC for the automatic single-parameter strategy < 63). However, by use of additional image parameters, an automatic multiparameter strategy has significantly improved performance with respect to the manual Arcidiacono method (78 < AUROC < 90). The automatic multiparameter strategy is a valuable alternative to the manual Arcidiacono method, improving both diagnostic speed and diagnostic accuracy.     

Adiponectin and vulnerable atherosclerotic plaques

High-risk plaques that are vulnerable to rupture demonstrate distinct morphological characteristics. They are differentiated from the lesions responsible for stable coronary artery disease by their large necrotic cores, thin-inflamed fibrous caps, and positive remodeling. Adiponectin is an adipocytokine that is reduced in obesity and type 2 diabetes. Hypoadiponectinemia has been associated with an increased risk of coronary artery disease and acute coronary syndrome in several though not all studies. The involvement of adiponectin provides clues to the inflammatory and atherogenic mechanisms associated with pathological coronary disease progression.     

Ultrastructural changes of venous autologous bypass grafts in rabbits: Correlation of patency and development

Summary Electron microscopic techniques were used to correlate the patency of venous autografts in rabbits with ultrastructural changes within a time range from 5 days to 6 months p.o. Early degenerative changes of the grafts include endothelial desquamation followed by fibrin deposition or platelet adhesion, mural edema and extensive medial and adventitial degeneration. The regeneration of the grafts is due to an early adventitial vascularization (10 days p.o.), which enables the surviving smooth muscle cells and fibrocytes to proliferate and to develop an arterial-like vessel. The organization of the 6-month-old graft is comparable to the carotid artery of the animal, but shows, in contrast, many features of a muscular artery.

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Zusammenfassung Mit Hilfe elektronenmikroskopischer Methoden wurde versucht, die Funktionsfähigkeit autologer Venentransplantate mit ultrastrukturellen Veränderungen in einem Zeitraum von 5 Tagen bis 6 Monaten p. o. zu korrelieren. Frühe degenerative Veränderungen der Transplantate umfassen Endothelabschilferungen mit anschließender Fibrin- bzw. Plättchenauflagerung, murale Ödeme und ausgedehnte mediale und adventitielle Degenerationen. Die Regeneration der Transplantate wird ermöglicht durch eine frühe adventitielle Kapillarisierung (10 Tage p. o.), die die überlebenden glatten Muskelzellen und Fibrozyten in die Lage versetzt, zu proliferieren und ein arterienähnliches Gefäß zu entwickeln. Der Aufbau der 6 Monate alten Vene ist vergleichbar mit der Arteria carotis communis der Tiere, zeigt aber im Gegensatz dazu überwiegend Merkmale einer Arterie vom muskulären Typ.