The Experts below are selected from a list of 240 Experts worldwide ranked by ideXlab platform

Jennifer E Van Eyk - One of the best experts on this subject based on the ideXlab platform.

Renu Virmani - One of the best experts on this subject based on the ideXlab platform.

  • pathology of acute and chronic coronary stenting in humans
    Circulation, 1999
    Co-Authors: Andrew Farb, Giuseppe Sangiorgi, Andrew J Carter, Virginia M Walley, William D Edwards, Robert S Schwartz, Renu Virmani
    Abstract:

    Background—Despite the increasing use of stents, few reports have described human coronary artery morphology early and late after stenting. Methods and Results—Histology was performed on 55 stents in 35 coronary vessels (32 native arteries and 3 vein grafts) from 32 patients. The mean duration of stent placement was 39±82 days. Fibrin, platelets, and neutrophils were associated with stent struts ≤11 days after deployment. In stents implanted for ≤3 days, only 3% of struts in contact with Fibrous Plaque had >20 associated inflammatory cells compared with 44% of struts embedded in a lipid core and 36% of struts in contact with damaged media (P<0.001). Neointimal growth determined late histological success, and increased neointimal growth correlated with increased stent size relative to the proximal reference lumen area. Neointimal thickness was greater for struts associated with medial damage than struts in contact with Plaque (P<0.0001) or intact media (P<0.0001). When matched for time since treatment, neo...

  • coronary risk factors and Plaque morphology in men with coronary disease who died suddenly
    The New England Journal of Medicine, 1997
    Co-Authors: Allen P Burke, Andrew Farb, Youhui Liang, John E Smialek, Gray T Malcom, Renu Virmani
    Abstract:

    Background Cigarette smoking and abnormal serum cholesterol concentrations are risk factors for acute coronary syndromes, but the underlying mechanisms are poorly understood. We studied whether cigarette smoking and abnormal cholesterol values may precipitate acute coronary thrombosis and sudden death resulting from either rupture of vulnerable coronary Plaques or erosion of Plaques. Methods We examined the hearts of 113 men with coronary disease who had died suddenly and also analyzed their coronary risk factors. We found an acute coronary thrombus in each of 59 men, and severe narrowing of the coronary artery by an atherosclerotic Plaque without acute thrombosis (stable Plaque) in 54. Cases of acute thrombosis were divided into two groups: 41 resulting from rupture of a vulnerable Plaque (a thin Fibrous cap overlying a lipid-rich core), and 18 resulting from the erosion of a Fibrous Plaque rich in smooth-muscle cells and proteoglycans. Vulnerable Plaques that had not ruptured were counted in each heart....

Sarah J Parker - One of the best experts on this subject based on the ideXlab platform.

Kosei Yasumoto - One of the best experts on this subject based on the ideXlab platform.

  • Matrix Metalloproteinase 12 Accelerates the Initiation of Atherosclerosis and Stimulates the Progression of Fatty Streaks to Fibrous Plaques in Transgenic Rabbits
    American Journal of Pathology, 2008
    Co-Authors: Sohsuke Yamada, Teruo Watanabe, Ke-yong Wang, Akihide Tanimoto, Shohei Shimajiri, Shuji Kitajima, Masatoshi Morimoto, Masato Tsutsui, Kosei Yasumoto
    Abstract:

    Whether fatty streaks are directly followed by Fibrous Plaque formation in atherosclerosis remains controversial. Disruption of the basement membrane and elastic layers is thought to be essential for this process. Matrix metalloproteinase 12 (MMP-12) can degrade a broad spectrum of substrates, but the role of MMP-12 in the early stage of atherosclerosis is unclear. To investigate MMP-12 function in the initiation and progression of atherosclerosis, we investigated macrophage migration and elastolysis in relation to fatty streaks in human MMP-12 transgenic (hMMP-12 Tg) rabbits. Fatty streaks in hMMP-12 Tg rabbits fed a 1% cholesterol diet for 6 weeks (cholesterol-induced model of atherosclerosis) were more pronounced and were associated with more significant degradation of the internal elastic layer compared with wild-type (WT) animals. Numbers of infiltrating macrophages and smooth muscle cells in the lesions were increased in hMMP-12 Tg compared with WT animals. In both cuff- and ligation-induced models of atherosclerosis, smooth muscle cell-predominant atherosclerotic lesions were elevated with significant elastolysis of the internal elastic lamina in Tg compared with WT animals; “microelastolytic sites” were recognized before formation of the neointima in the cuff model only. These results indicate that MMP-12 may be critical to the initiation and progression of atherosclerosis via degradation of the elastic layers and/or basement membrane. Therefore, a specific MMP-12 inhibitor might prove useful for the treatment of progressive atherosclerosis.

Francisco J B Sampaio - One of the best experts on this subject based on the ideXlab platform.

  • stereological and biochemical analysis of muscular and connective tissue components in the penile corpus cavernosum adjacent to the Fibrous Plaque of peyronie s disease
    BJUI, 2009
    Co-Authors: Waldemar S Costa, Sabrina B Rebello, Luiz E M Cardoso, Andre G Cavalcanti, Francisco J B Sampaio
    Abstract:

    OBJECTIVE To investigate the structural organization of the connective tissue in the corpus cavernosum (CC) adjacent to the Fibrous Plaque in Peyronie’s disease (PD) using stereological and biochemical techniques, as most studies on PD have focused on the analysis of the Fibrous Plaque that forms in the tunica albuginea (TA). Because this fibrotic reaction is mediated by various inflammatory soluble factors, adjacent connective tissues might also be affected and this secondary effect might explain, for example, the erectile dysfunction that occurs in PD. PATIENTS AND METHODS During surgery biopsies were taken from the CC adjacent to the Fibrous Plaque and from the Plaque itself in seven patients with PD (mean age 48.3 years). All the patients had normal erections. Control samples were similarly located samples from ‘normal’ penises obtained during autopsy of five men (mean age 52.3 years). Tissue samples were stained with Weigert’s stain (elastic fibres), Van Gieson’s stain (connective tissue), and Sirius red (collagen). Stereological analysis was done using a 42-point grid to determine volumetric densities (Vv). Total collagen content was estimated as micrograms of hydroxyproline per milligram dry CC. RESULTS The Vv of elastic fibres was significantly reduced in PD by 17.3% compared with controls, at a mean (sd) of 19.49 (3.27)% vs 23.56 (1.87)% (P < 0.05). While in PD the Vv of smooth muscle at 34.46 (2.06)% and connective tissue at 35.39 (6.15)% were not significantly different from those of controls at 38.38 (3.17)% and 38.02 (5.03)%, respectively. The Vv of elastic fibres in the Fibrous Plaque was decreased by 38.3% compared with the normal TA, at 20.25 (5.49)% vs 32.81 (4.75)% (P < 0.02). The mean (sd) collagen concentration in the CC from controls was 77.94 (24.26) µg/mg and in the patients with PD was 66.57 (19.39) µg/mg, which did not differ significantly. Sirius red-stained sections under polarized light showed that, in the normal CC, collagen-associated colours were homogeneously distributed. However, in the PD samples, stained collagen had a disrupted orientation and had a more heterogeneous birefringence, implying looser collagen bundles. CONCLUSIONS The quantitative analyses indicated that collagen in the CC close to the Fibrous Plaque was not affected, although its organization was noticeably altered. The CC elastic fibres were reduced though, and there was a similar change in the Fibrous Plaque of the TA. These results suggest that, although occurring primarily in the TA, the PD Fibrous Plaque may induce changes in the adjacent CC.

  • Stereological and biochemical analysis of muscular and connective tissue components in the penile corpus cavernosum adjacent to the Fibrous Plaque of Peyronie's disease.
    BJU international, 2008
    Co-Authors: Waldemar S Costa, Sabrina B Rebello, Luiz E M Cardoso, Andre G Cavalcanti, Francisco J B Sampaio
    Abstract:

    OBJECTIVE To investigate the structural organization of the connective tissue in the corpus cavernosum (CC) adjacent to the Fibrous Plaque in Peyronie’s disease (PD) using stereological and biochemical techniques, as most studies on PD have focused on the analysis of the Fibrous Plaque that forms in the tunica albuginea (TA). Because this fibrotic reaction is mediated by various inflammatory soluble factors, adjacent connective tissues might also be affected and this secondary effect might explain, for example, the erectile dysfunction that occurs in PD. PATIENTS AND METHODS During surgery biopsies were taken from the CC adjacent to the Fibrous Plaque and from the Plaque itself in seven patients with PD (mean age 48.3 years). All the patients had normal erections. Control samples were similarly located samples from ‘normal’ penises obtained during autopsy of five men (mean age 52.3 years). Tissue samples were stained with Weigert’s stain (elastic fibres), Van Gieson’s stain (connective tissue), and Sirius red (collagen). Stereological analysis was done using a 42-point grid to determine volumetric densities (Vv). Total collagen content was estimated as micrograms of hydroxyproline per milligram dry CC. RESULTS The Vv of elastic fibres was significantly reduced in PD by 17.3% compared with controls, at a mean (sd) of 19.49 (3.27)% vs 23.56 (1.87)% (P