Ultrastructure of the human aortic fibrolipid lesion. Formation of the atherosclerotic lipid-rich core.

The formation of the atherosclerotic lipid-rich core has been elucidated by electron microscopy of the core region in small, raised fibrolipid lesions. The relationship among lipid deposits, extracellular matrix, and cells found in distinct regions of the fibrolipid lesion was examined. Extracellular lipid droplets, verified by osmium-thiocarbohydrazide-osmium staining, made up approximately 40% of the lipid-rich core volume. The lipid droplets were often found distinctly associated with elastin and/or collagen; these associations were dependent upon the location examined within or near the lipid-rich core. Within areas of intense extracellular lipid deposits, crystalline clefts suggesting cholesterol monohydrate were observed. Stereologic analysis of the lipid-rich core components revealed marked reductions in the volume fractions of cells, reticular ground substance, and basement membrane; while the extent of extracellular lipid increased 7-10-fold. Eleven percent or less of lipid in the core region was found within cells, usually smooth muscle cells. Above the core region in the lesion cap, monocyte-macrophage foam cells were prominent. Cellular lipid droplets were much larger (profile diameters sixfold higher) than extracellular droplets. With these data as well as transitional morphologic features at the boundaries of the core region, it is suggested that the abundant extracellular lipid does not derive from cell necrosis, and lipid deposition in association with extracellular matrix constituents is an early event in the development of the lipid-rich core.     

The lipid-rich core region of human atherosclerotic fibrous plaques. Prevalence of small lipid droplets and vesicles by electron microscopy.

Abundant extracellular lipid deposits are associated with cell necrosis and tissue weakening in the core region of human atherosclerotic fibrous plaques. The ultrastructural morphology of the core region, previously undefined because of lipid extraction artifacts, was studied with the aid of new osmium-thiocarbohydrazide-osmium and osmium-tannic acid-paraphenylenediamine sequences for tissue processing. Small droplets of neutral lipid (30 to 400 nm profile diameter) and lipid vesicles with aqueous centers accounted for more than 90% of the area occupied by lipid-rich structures in the core region. No foam cells were present. Cholesterol crystals, lipid droplets of a size similar to those in foam cells (0.4 to 6 mu), and larger neutral lipid deposits (greater than 6 mu) together occupied less than 10% of the total area of lipid structures. Abundant lipid vesicles were associated with the nearby presence of cholesterol crystals, whereas small lipid droplets were predominant in areas without crystals. Many droplets had surface defects in the form of pits and vesicular blebs. These morphologic findings are explained most concisely by postulating direct accumulation of extracellular lipid from interstitial lipoproteins as a major process in core region formation. Moreover, a dynamic state of ongoing physical/metabolic transformation of extracellular lipid deposits is suggested.     

Unesterified cholesterol-rich lipid particles in atherosclerotic lesions of human and rabbit aortas.

Unesterified cholesterol-rich lipid particles were isolated from human and cholesterol-fed rabbit aortas. These particles have been previously reported to constitute the initial lipid deposition in atherosclerotic lesion development. Purification of the particles was accomplished with microfiltration, gel filtration chromatography, and density gradient centrifugation. Particles from both human and rabbit aortas had a density of between 1.02 g/ml and 1.08 g/ml with a peak at d = 1.036 g/ml. These particles had a high molar ratio of unesterified cholesterol to phospholipid (2.4:1 in rabbit, 2.6:1 in human) and a high percentage of their cholesterol in an unesterified form (82% in rabbit, 76% in human). The particles had diameters between 700 and 3000 A and showed unilamellar and multilamellar structures. Freeze-fractured particles had smooth fracture faces and sometimes contained a smooth-surfaced core. Upon incubation with filipin, particles showed typical filipin-sterol complexes, demonstrating the presence of unesterified cholesterol. The particles we have isolated may constitute an early pathologic form of accumulated cholesterol in developing lesions and may represent a degradation product of infiltrated plasma low-density lipoprotein.     

The prevalence of ulcerated plaques in the aortic arch in patients with stroke.

BACKGROUND AND METHODS. The cause of cerebral infarction is obscure in up to 40 percent of patients with this disorder who are studied prospectively. In this investigation, we determined the frequency of ulcerated plaques in the aortic arch and explored the part they may play in the formation of cerebral emboli. Using an autopsy data bank, we studied the prevalence of ulcerated plaques in the aortic arch in 500 consecutive patients with cerebrovascular and other neurologic diseases who were studied at autopsy. RESULTS. Ulcerated plaques were present in 26 percent of the 239 patients with cerebrovascular disease but in only 5 percent of the 261 patients with other neurologic diseases (P less than 0.001). After we controlled for age and heart weight, the adjusted rates were 16.9 percent and 5.1 percent, respectively (adjusted odds ratio, 4.0; 95 percent confidence interval, 2.1 to 7.8; P less than 0.001). Among the patients with cerebrovascular disease, the prevalence of ulcerated plaques in the aortic arch was 28 percent in the 183 patients with cerebral infarcts and 20 percent in the 56 patients with brain hemorrhage. The prevalence of ulcerated plaques was 61 percent among the 28 patients with no known cause of cerebral infarction, as compared with 22 percent among the 155 patients with a known cause of cerebral infarction (P less than 0.001). After adjustment for covariates, the prevalence was 57.8 percent among patients with no known cause of cerebral infarction and 20.2 percent among those with a known cause (adjusted odds ratio, 5.7; 95 percent confidence interval, 2.4 to 13.6; P less than 0.001). The presence of ulcerated plaques in the aortic arch was not correlated with the presence of extracranial internal-carotid artery stenosis, suggesting that these were two independent risk factors for stroke. CONCLUSIONS. Ulcerated plaques in the aortic arch may play a part in causing cerebral infarction, especially in patients in whom cerebral infarction has no known cause.     

Mechanism of fibrous capsule formation surrounding hepatocellular carcinoma. Immunohistochemical study.

In 14 cases of hepatocellular carcinoma with capsule, we studied the mechanism of capsule formation by the immunoperoxidase technique using antibodies to types I, III, and IV collagen, antilaminin antibody, and anti-prolyl hydroxylase antibody. Marked round cell infiltration was observed in the noncancerous side of the capsule and around compressed hepatocytes near the capsule. Thin capsules were composed primarily of type III collagen produced by an increased number of fibroblasts, transitional Ito cells, and hepatocytes near the capsule. In thickened capsules, the noncancerous side consisted primarily of type III collagen and the cancerous side of types I and III collagen. Type I as well as type III collagen was produced by fibroblasts, transitional Ito cells, and hepatocytes. The capsule thus formed is suggested to be part of the defense mechanisms against the growth of hepatocellular carcinoma.     

Unusual fibrous band on the left aspect of the aortic arch

During dissection of a 63-year-old female cadaver, a firm ribbon-like band was found on the left aspect of the aortic arch. Careful dissection showed that the band (6 cm long, 8 mm wide, 2 mm thick) connected the left superior intercostal vein with the accessory hemiazygos vein. Histological examination showed the fibrous structure of the band and showed the presence of a thread-like vascular lumen. The topography and venous connections of the band indicated its origin from persistence of the embryonic anastomosis between the left superior intercostal and accessory hemiazygos veins. This anastomosis derives from the rostral portion of the supracardinal vein that usually regresses on the left side but forms the terminal arch of the azygos vein on the right side. The severe atherosclerosis present in this patient at the level of the aortic arch may have enhanced the effects of arterial pressure on the adjacent venous anastomotic vessel causing reduction of blood flow and progressive fibrosis. The persistence of this venous anastomosis and its possible age-related fibrosis may have clinical relevance in central venous catheter placement.     

Electron micrograph of diffuse plaques. Initial stage of senile plaque formation in the Alzheimer brain.

The ultrastructure of diffuse plaques (devoid of both amyloid core and swollen neurites) in the frontal cortex of an Alzheimer brain was examined, using paired routine electron microscopic ultrathin sections and adjacent 0.4-micron-thick semithin sections. The semithin sections, treated with formic acid and beta protein immunostain, showed abundant diffuse plaques. In the adjacent ultrathin section, diffuse plaques usually showed some scattered bundles of amyloid fibrils between focally blurred membranes of cell process. The diffuse plaques were nearly undetectable without the semithin beta protein immunostained preparations, because the neuropils within these plaques appeared almost normal morphologically. Capillaries, which rarely appeared in the center of the diffuse plaques, demonstrated no amyloid fibrils in their walls. These findings suggest that in the initial stages of senile plaque formation amyloid fibrils are formed sporadically between cell processes, but not around the capillaries.     

Egfl7 Represses the Vasculogenic Potential of Human Endothelial Progenitor Cells

Egfl7 (VE-statin) is a secreted protein mostly specific to the endothelial lineage during development and in the adult and which expression is enhanced during angiogenesis. Egfl7 involvement in human postnatal vasculogenesis remains unresolved yet. Our aim was to assess Egfl7 expression in several angiogenic cell types originating from human bone marrow, peripheral blood, or cord blood. We found that only endothelial colony forming cells (ECFC), which are currently considered as the genuine endothelial precursor cells, expressed large amounts of Egfl7. In order to assess its potential roles in ECFC, Egfl7 was repressed in ECFC by RNA interference and ECFC angiogenic capacities were tested in vitro and in vivo. Cell proliferation, differentiation, and migration were significantly improved when Egfl7 was repressed in ECFC in vitro, whereas miR-126-3p levels remained unchanged. In vivo, repression of Egfl7 in ECFC significantly improved post-ischemic revascularization in a model of mouse hind-limb ischemia. In conclusion, ECFC are the sole postnatal angiogenic cells which express large amounts of Egfl7 and whose angiogenic properties are repressed by this factor. Thus, Egfl7 inhibition may be considered as a therapeutic option to improve ECFC-mediated postnatal vasculogenesis and to optimize in vitro ECFC expansion in order to develop an optimized cell therapy approach.     

Consequences of intramyocardial arterial lesions in aortic valvular stenosis.

Proliferative lesions, which included collagen deposition, developed with age in intramyocardial arteries of 27 patients with aortic stenosis and matched controls. Those with the most extensive intramyocardial artery lesions developed massive subendocardial infarcts during surgery. Using histologic quantitation, the percent of intramyocardial arteries with lesions in a patient was correlated with decreases in the amount of muscle in arterioles between the subepicardial and subendocardial zones of the left ventricle. The mean decrease in arteriolar muscle was 43% in patients with aortic stenosis and 19% in controls. Blood pressures correlate with the amount of muscle in arterioles, so subendocardial perfusing pressures were presumably low in those with aortic stenosis. Patients with the greatest decrease in arteriolar muscle across the myocardium had the most impaired left ventricular function, i.e., highest end diastolic pressures, lowest ejection fractions, and lowest mean fiber shortening rates.     

Experimental aortic lesions of acute serum sickness in rabbits.

The mechanisms by which serum sickness cause lesions in the aortic intima are not known. The early aortic lesions of serum sickness detected by permeability to Evans blue dye were studied morphologically to determine the chronologic sequence of lesion initiation and immunochemically with fluorescein-labeled rabbit IgG and bovine serum albumin to detect the presence of antigen and antibody. The topographic localization of lesions and the morphologic changes observed suggest that endothelial injury occurs first, probably due to immune complex deposition, and that platelets play a secondary or reactive role in the process.     

Fine-needle aspiration cytology vs. core biopsy in the diagnosis of breast lesions

Fine-needle aspiration cytology (FNAC) is an established, highly accurate method for diagnosing breast lesions. However, in recent years there has been increased use of core biopsy (CB) in this setting. The aim of this study was to evaluate the accuracy of FNAC and compare the quality assessment parameters of FNAC and CB in palpable and nonpalpable breast lesions. Data regarding FNAC, CB, and excision biopsy (EB) diagnoses were retrieved from the archives of our department. A total of 4,367 FNAC samples from the years 1999-2001 was reviewed. Of these, corresponding histology results were available for 1,275 lesions, of which 1,248 were primary breast epithelial lesions (788 EB, 199 CB, 261 EB+CB). All cases were analyzed for sensitivity and specificity of FNAC. Cases with both FNAC and CB were compared and quality assessment parameters were calculated using the methodology detailed in the National Health Service Breast Screening Program guidelines. High specificity and sensitivity, as calculated for satisfactory specimens, were achieved with the use of both FNAC and CB. False-positive and false-negative diagnoses were seen in 7/404 (1.7%) and 45/635 (7.1%) of biopsy-proven specimens sampled by FNAC. The corresponding values for CB were 0% and 5.7%, respectively. Inadequate sampling (15.1%) with use of FNAC was particularly seen in collagenous lesions and in submitted specimens sampled by physicians lacking experience with the FNAC procedure. FNAC is a valuable method, although moderately less sensitive than CB. CB is the preferred method for preoperative diagnosis when sampling FNAC provides scarce material and suspicion of a fibrotic and collagenous lesion such as lobular carcinoma and radial scar arises. FNAC is most accurate when experienced cytologists are available and when immediate assessment by professionals is performed for evaluation of material adequacy, so that additional aspirations can be done when needed.     

Learning deficits in rats with early neurotoxic lesions to the globus pallidus, substantia nigra, median raphe or pontine reticular formation

Previous studies have shown that weanling rats with electrolytic lesions of the globus pallidus (GP), substantia nigra (SN), median raphe (MR) or pontine reticular formation (PRF) are deficient in learning a wide variety of laboratory tasks. The current study was designed to investigate whether this nonspecific learning deficiency is due to destruction of cells intrinsic to these subcortical regions or to fibers passing through these regions. Accordingly, neurotoxic lesions of the GP, SN, MR or PRF were made in weanling rats using ibotenic acid. Rats were subsequently required to learn a visual discrimination, a 3-cul maze and a nonvisual (incline plane) discrimination. While those groups with GP, SN or MR lesions showed significant deficits on all three problems, only the animals with GP lesions exhibited deficits comparable in magnitude to those associated with corresponding electrolytic lesions. Animals with lesions to the PRF were impaired only on the nonvisual discrimination. These results suggest that while destruction of neurons alone within the GP, SN or MR can produce a nonspecific learning impairment, the combined destruction of neurons and fibers of passage within the SN, MR or PRF produces a more profound learning deficit.     

人脐血内皮祖细胞的分离、培养及鉴定

目的探索人脐静脉血内皮祖细胞的分离培养,为内皮祖细胞的临床应用提供实验方法。方法选择脐静脉血,应用密度梯度离心法,获取单个核细胞,接种于预先包埋了人纤维连接蛋白的培养板,用加入生长因子VEGF165和bFGF的内皮细胞专用培养基EGM-2MV培养细胞,3d后,洗掉非贴壁细胞,换培养液继续培养至7d,收集贴壁细胞进行细胞分析。激光共聚焦显微镜进行细胞功能学鉴定,流式细胞术测定祖细胞和内皮细胞系标志。MTT比色法检测细胞的生长状态。结果经过梯度密度离心和贴壁法选择的细胞能特异性吸附FITC标记的荆豆凝集素并内吞DiI-acLDL,祖细胞标志CD133及内皮细胞特异性抗原CD34、KDR检测,其阳性率分别为（27．05±2．94）％、（16．37±2．69）％和（56．67±7．29）％;体外培养的内皮祖细胞具有良好的细胞增殖活性。结论人脐静脉血中可以分离培养内皮祖细胞,为内皮祖细胞的进一步研究及临床应用奠定了基础。     

A rapid method for the detection of early stages of atherosclerotic lesion formation.

A simple, rapid technique for detecting early changes in the arterial vessels of rats and rabbits fed an atherogenic diet is described. After perfusion fixation, the descending thoracic aorta was cytochemically stained with oil red O to detect intracellular lipid and with Hoechst 33342 dye to detect nuclear DNA. The vessels were whole mounted and the luminal surface examined en face using both transmitted light and epifluorescence microscopy. With this technique it is possible to identify and quantitate mononuclear cells adhering to the vessel wall, determine the distribution and number of intimal foam cells within the intima, and determine the mitotic index of the endothelium. Tissue samples can be quickly prepared using this technique, thus allowing rapid analysis of the influence of various substances on the early stages of atherosclerotic lesion formation in animals fed an atherogenic diet.     

Human papillomavirus DNA in glandular lesions of the uterine cervix.

AIMS--To assess the role of human papillomavirus in the pathogenesis of adenocarcinoma in situ, endocervical glandular dysplasia (a presumed precursor of adenocarcinoma) and endocervical glandular epithelial giant cell change. METHODS--Viral detection was carried out using an in situ hybridisation technique on paraffin wax sections. Biotinylated probes for human papillomavirus types 6/11, 16/18, 31/33/35 were used with a colorimetric detection system. RESULTS--Nine out of 21 (43%) cases of adenocarcinoma in situ contained human papillomavirus types 16/18, one of which was also positive for 31/33/35. Ten cases of glandular dysplasia and four cases of glandular epithelial multinucleation did not react with the probes used. CONCLUSIONS--These results indicate that while adenocarcinoma in situ is strongly associated with human papillomavirus infection, endocervical glandular dysplasia and glandular epithelial multinucleation are probably not associated with the virus.     

髓芯减压术后二次减压治疗早中期股骨头坏死

目的回顾性分析髓芯减压术后二次减压术治疗早中期股骨头坏死(ONFH)的临床疗效。 方法选取2008年7月至2013年4月于安徽医科大学解放军第三〇七医院只接受股骨头髓芯减压、死骨刮除、人工骨打压植入术治疗的30例(50髋)ONFH患者,设为单次减压组;选取2010年1月至2013年4月于安徽医科大学解放军第三〇七医院接受单次髓芯减压术术后半年同意行二次减压治疗的30例(42髋)ONFH患者,设为二次减压组。按照国际骨循环研究会分期,所有ONFH均为Ⅰ期、Ⅱ期。采用髋关节Harris评分系统评估术后患髋功能改善情况,应用视觉模拟评分法(VAS)进行临床疼痛测定,通过影像学(X线、CT、磁共振成像)评定股骨头是否塌陷及病灶修复情况。组间数据采用t检验、χ²检验进行比较分析。 结果60例(92髋)ONFH患者术后均获得随访,随访时间为25～84个月。术后25个月时,两组髋关节Harris评分较术前均有显著提高,差异均有统计学意义(P值均小于0.05);二次减压组髋关节Harris评分[(91.21±3.32)分]显著高于单次减压组[(81.60±2.60)分],差异有统计学意义(t＝－15.592,P<0.05)。两组VAS评分较术前均有显著降低,差异均有统计学意义(P值均小于0.05);二次减压组VAS评分[(2.20±0.71)分]显著低于单次减压组[(3.27±1.51)分],差异有统计学意义(t＝3.503,P＝0.001)。单次减压组髋关节Harris评分优2髋,良36髋,尚可5髋,优良率为76.0%,股骨头保存率为86.0%;二次减压组髋关节Harris评分优35髋,良5髋,尚可2髋,优良率为95.2%,股骨头保存率为100.0%。两组髋关节Harris评分优良率比较差异有统计学意义(χ²＝6.548,P＝0.011),两组股骨头保存率比较差异有统计学意义(χ²＝4.529,P＝0.033)。两组髋关节Harris评分为优的37髋的股骨头外形修复均完整;评分为良的41髋中有6髋外形不圆,但股骨头内未出现骨折,剩余基本维持球形;评分为差的7髋出现软骨下骨折、关节间隙狭窄,其中3髋行全髋关节置换术。 结论髓芯减压术后二次减压术可再次诱发股骨头内创伤修复过程,进一步改善患髋功能、减轻髋关节疼痛,起到较好的治疗作用。