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Microvascular Changes (microvascular + change)
Selected AbstractsEffect of smoking on the gingival capillary density: assessment of gingival capillary density with orthogonal polarization spectral imagingJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 12 2005J. A. Lindeboom Abstract Objectives: Microvascular changes because of smoking are frequently presumed in models because of the negative effect of smoking portrayed on the microcirculation. We hypothesized that cigarette smoke might lead to a decrease in gingival capillary density. Materials and Methods: Capillary density was assessed with orthogonal polarization spectral (OPS) imaging, a technique using special optics by which a virtual light source is created at a depth of 1 mm within the mucosa. The light is absorbed by haemoglobin, resulting in an image of the capillaries in negative contrast. The gingival capillary density was measured in 20 healthy male dental students with a mean age of 25. Ten of the students were smokers and 10 were non-smokers. In each subject six images of the right maxillary pre-molar region were obtained, and the mean gingival capillary density was determined through the use of K&K software technology. Results: The mean capillary density in smokers was 69.3±8.9 capillaries per visual field compared with a mean capillary density in non-smokers of 60.6±5.4 (p=0.33). Conclusion: No significant differences were found between the gingival capillary density of smokers and non-smokers. [source] Microvascular changes and anesthesiaACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 5 2002R. G. Hahn No abstract is available for this article. [source] IMPACT OF BLOOD FLOW OCCLUSION ON LIVER NECROSIS FOLLOWING THERMAL ABLATIONANZ JOURNAL OF SURGERY, Issue 1-2 2006Mehrdad Nikfarjam Background: Laser, radiofrequency and microwave are common techniques for local destruction of liver tumours by thermal ablation. The main limitation of thermal ablation treatment is the volume of necrosis that can be achieved. Blood flow occlusion is commonly advocated as an adjunct to thermal ablation to increase the volume of tissue necrosis based on macroscopic and histological assessment of immediate or direct thermal injury. This study examines the impact of blood flow occlusion on direct and indirect laser induced thermal liver injury in a murine model using histochemical methods to assess tissue vitality. Methods: Thermal ablation produced by neodymium yttrium-aluminium-garnet laser (wavelength 1064 nm) was applied to the liver of inbred male CBA strain mice at 2 W for 50 s (100 J). Treatment was performed with and without temporary portal vein and hepatic artery blood flow occlusion. Animals were killed upon completion of the procedure to assess direct thermal injury or at 24, 48 and 72 h to assess the progression of tissue damage. The maximum diameter of necrosis was assessed by vital staining for nicotinamide adenine dinucleotide (NADH) diaphorase. Microvascular changes were assessed by laser Doppler flowmetry, confocal in vivo microscopy and scanning electron microscopy. Results: The direct thermal injury (mean SE) assessed by NADH diaphorase staining was significantly greater following thermal ablation treatment without blood flow occlusion than with blood flow occlusion (3.3 (0.4) mm vs 2.9 (0.3) mm; P = 0.005). Tissue disruption, cracking and vacuolization was more pronounced adjacent to the fibre insertion site in the group treated with thermal ablation combined with blood flow occlusion. There was an equivalent increase in the extent of injury following therapy in both groups that reached a peak at 48 h. The maximum diameter of necrosis in the thermal ablation alone group at 48 h was significantly greater than the thermal ablation combined with blood flow occlusion group (5.8 (0.4) mm vs 5.3 (0.3) mm; P = 0.011). The patterns of microvascular injury were similar in both groups, varying in extent. Conclusion: Temporary blood flow inflow occlusion appears to decrease the extent of initial injury measured by vital staining techniques and does not alter the time sequence of progressive tissue injury following thermal ablation therapy. [source] A REVIEW OF CURRENT CLINICAL APPLICATIONS OF UPPER GASTROINTESTINAL ZOOM ENDOSCOPYDIGESTIVE ENDOSCOPY, Issue 2005Kenshi Yao Current clinical applications of upper gastrointestinal (GI) zoom endoscopy were reviewed. The objective of upper GI zoom endoscopy has been the diagnosis of neoplastic lesions as well as the diagnosis of minute inflammatory mucosal change. The target organ and pathology of the neoplastic lesions have been squamous cell carcinoma in the oro- and hypo-pharynx and in the esophagus; intestinal metaplasia, dysplasia, and adenocarcinoma in Barrett's esophagus; and adenocarcinoma in the stomach. For analyzing the magnified endoscopic findings, there were two different basic principles (mucosal microstructural change and subepithelial microvascular changes). Overall diagnostic accuracy for diagnosing a neoplastic lesion was above 80% throughout the upper GI tract. Although the diagnostic accuracy of the zoom endoscopy technique seems to be superior to that of the ordinary endoscopy technique alone, the continuous efforts to establish standardized guidelines and procedures are mandatory in order to lead to the routine use of upper GI zoom endoscopy in clinical practice. [source] Retinal vascular image analysis as a potential screening tool for cerebrovascular disease: a rationale based on homology between cerebral and retinal microvasculaturesJOURNAL OF ANATOMY, Issue 4 2005Niall Patton Abstract The retinal and cerebral microvasculatures share many morphological and physiological properties. Assessment of the cerebral microvasculature requires highly specialized and expensive techniques. The potential for using non-invasive clinical assessment of the retinal microvasculature as a marker of the state of the cerebrovasculature offers clear advantages, owing to the ease with which the retinal vasculature can be directly visualized in vivo and photographed due to its essential two-dimensional nature. The use of retinal digital image analysis is becoming increasingly common, and offers new techniques to analyse different aspects of retinal vascular topography, including retinal vascular widths, geometrical attributes at vessel bifurcations and vessel tracking. Being predominantly automated and objective, these techniques offer an exciting opportunity to study the potential to identify retinal microvascular abnormalities as markers of cerebrovascular pathology. In this review, we describe the anatomical and physiological homology between the retinal and cerebral microvasculatures. We review the evidence that retinal microvascular changes occur in cerebrovascular disease and review current retinal image analysis tools that may allow us to use different aspects of the retinal microvasculature as potential markers for the state of the cerebral microvasculature. [source] Noninvasive Imaging of Angiogenesis Inhibition Following Nitric Oxide Synthase Blockade in the Ischemic Rat Heart in VivoMICROCIRCULATION, Issue 4 2005CHRISTIANE WALLER MD ABSTRACT Objective: Nitric oxide synthase inhibition has anti-angiogenic properties. Magnetic resonance (MR) imaging was used to image the functional significance of these microvascular changes in a rat model of chronic ischemic myocardium in vivo. Methods: The authors quantitatively determined myocardial perfusion and regional blood volume, left ventricular geometry, and function using MR imaging. Animals received either L-NAME + hydralazine or no treatment and were investigated 1 and 2 weeks after induction of coronary artery stenosis or sham operation at rest and during vasodilatation. Double-labeling immunohistochemistry was used to visualize angiogenesis and to compare with data obtained by MR imaging. Results: Left ventricular mass and end-diastolic volumes were comparable in both groups 2 weeks after treatment. However, basal and maximum perfusion in animals with L -NAME + hydralazine treatment were reduced compared to animals not treated (p < .05). Basal regional blood volume remained constant in all groups, whereas maximum regional blood volume was reduced by L -NAME + hydralazine (p < .05). Endothelial cell proliferation, a direct marker for angiogenesis, was reduced by L -NAME + hydralazine (p < .01). Conclusions: MR imaging allows noninvasive quantification of functional microcirculation and angiogenesis in the rat heart in vivo. Nitric oxide synthase blockade results in changes in functional microcirculation and in an inhibition of angiogenesis in both ischemic and nonischemic myocardial tissue. [source] Microvascular Structure and Function in Salt-Sensitive HypertensionMICROCIRCULATION, Issue 4 2002Dr. Matthew A. Boegehold In many individuals with essential hypertension, dietary salt can further increase blood pressure by augmentation of an already elevated total peripheral resistance. There is little information on the microvascular changes that contribute to salt-sensitive hypertension in humans, but studies in the Dahl salt-sensitive rat have provided some knowledge of the microcirculation in this form of hypertension. These studies, most of which have used intravital microscopy or isolated vessel technology, are the focus of this review. The salt-induced exacerbation of hypertension in Dahl rats is due to a uniform increase in hemodynamic resistance throughout most of the peripheral vasculature. In the spinotrapezius muscle, this resistance increase is largely due to the intense constriction of proximal arterioles. The mechanisms responsible for this increased arteriolar tone include increased responsiveness to oxygen and a loss of tonic nitric oxide (NO) availability caused by reduced endothelial NO production and/or accelerated NO degradation by reactive oxygen species. Within the last decade, it has become increasingly clear that high salt intake can also lead to changes in microvascular structure and function in the absence of increased arterial pressure. This effect must also be considered when evaluating microvascular changes and their functional consequences in salt-sensitive hypertension. [source] The 2007 WHO Classification of Tumors of the Nervous System: Controversies in Surgical NeuropathologyBRAIN PATHOLOGY, Issue 3 2008Bernd W. Scheithauer MD Abstract Controversy surrounds the recent 2007 WHO Classification of Tumours of the Nervous System. A number of nosologic issues remain to be resolved, some a reflection of conceptual disagreement, others the result of inadequate data to permit their definitive resolution. Among these and discussed herein are (i) the nosologic place of highly anaplastic oligoastrocytic tumors, (ii) the forms and significance of microvascular changes in high-grade gliomas, (iii) the makeup of the glioneuronal tumors category, (iv) the subclassification of pineal parenchymal tumors of intermediate type, and (v) the classification of principle forms of mesenchymal neoplasms, specifically hemangiopericytoma and solitary fibrous tumor. These issues and others are the substance of this and an upcoming companion article. [source] Gastric mucosal resistance to acute injury in experimental portal hypertensionBRITISH JOURNAL OF PHARMACOLOGY, Issue 1 2001Sara Calatayud The gastric mucosa of portal hypertensive rats exhibits important microvascular changes and a nitric oxide (NO)-dependent hyperemia. This study analyses whether portal hypertensive mucosa exhibits changes in its ability to withstand aggression. Portal hypertension was induced by partial portal vein ligation (PPVL) or common bile duct ligation (CBDL) and gastric damage was induced by oral administration of ethanol or aspirin. Experiments were performed in conscious or anaesthetized rats and some animals were pre-treated with the NO-synthesis inhibitor L -NAME. Conscious PPVL or CBDL rats showed an increased resistance to the damaging effects of ethanol. Oral administration of aspirin produced less gastric damage in PPVL conscious rats than in the control group. The protective effects of portal hypertension were maintained in animals anaesthetized with ketamine and absent when pentobarbital was employed. Pre-treatment with L -NAME restored the damaging effects of ethanol and aspirin in PPVL rats without modifying the level of damage in control animals. Gastric bleeding induced by oral aspirin, as measured by the luminal release of 51Cr-labelled erythrocytes, was significantly greater in PPVL rats than in control animals. Semi-quantitiative analysis by RT , PCR of the mRNA for endothelial NO-synthase (eNOS), neuronal NOS (nNOS) and inducible NOS (iNOS) levels showed that the expression of iNOS was slightly increased in both the gastric mucosa and smooth muscle of PPVL rats. No changes were observed in eNOS and nNOS expression. Conscious portal hypertensive rats exhibit an enhanced resistance to acute gastric damage which is absent under the influence of some types of anaesthesia and seems related to an increased synthesis of nitric oxide. However, mucosal lesions in these animals show an augmented bleeding per area of injury. British Journal of Pharmacology (2001) 132, 309,317; doi:10.1038/sj.bjp.0703785 [source] | ||||||||||