Basal deposits and drusen in eyes with age-related maculopathy: evidence for solid lipid particles

Neutral lipid, including esterified cholesterol, and apolipoproteins B and E are abundant in basal deposits and drusen of aged and age-related maculopathy (ARM) eyes. The principal component of basal linear deposit (BlinD), a specific ARM lesion, is membranous debris, which if actually derived from membranes cannot account for extracellular neutral lipid. We therefore used a lipid-preserving ultrastructural method to obtain improved images of membranous debris. Maculas from 44 human donors (71-96 yr) were preserved <7.5 hr after death. Blocks were post-fixed in 2% osmium or osmium-tannic acid-paraphenylenediamine (OTAP) to preserve neutral lipid for thin-section transmission electron microscopic (TEM) examination. Solid particles identified by OTAP were considered closest to the in vivo state of extracellular lipids. Micrographs were examined for intermediate forms, with greatest weight given to comparable images from different preparations of same or fellow eyes. Twenty eyes of older adults (12 with ARM including fellows treated with photodynamic and radiation therapies) had adequately preserved extracellular lipid. The exterior surface of membranous debris was thicker and more electron-dense than basal infoldings of retinal pigment epithelium (RPE) cells. By OTAP, individual membranous debris profiles were solid (diameters, 80-200 nm) and formed tracks across or aggregations within basal laminar deposits. Solid particles and/or pools of neutral lipid were visible in BlinD and drusen. When processed to preserve lipid, membranous debris resembles neither membranes of surrounding cells nor vesicles possessing aqueous interiors but rather solid particles. These results are consistent with recent evidence implicating lipoprotein particles of intra-ocular origin as a potential source of neutral lipids, including esterified cholesterol, in the specific lesions of ARM.     

慢性阻塞性肺疾病早期急性肺损伤对血管内皮形态的影响

目的观察慢性阻塞性肺疾病(COPD)大鼠模型造模早期急性肺损伤(ALI)对血管内皮形态的影响。方法健康雄性Wistar大鼠48只,随机分为空白组24只,COPD模型组24只。用气管内注入脂多糖(LPS)及烟熏方法制作COPD模型。分别于第2、15、28天随机处死模型组及空白组大鼠各8只进行血管内皮形态学观察。结果与空白组比较,光学显微镜下COPD模型组造模第2天部分血管壁不光滑,周围可见散在中性粒细胞及淋巴细胞浸润,少量肺间质血管可见充血;造模第15天则出现血管扩张,形态不规则,血管平滑肌不均匀,血管间质增生;造模第28天血管平滑肌增生明显,几乎占据整个血管管壁,周围有大量炎症细胞浸润。电子显微镜下COPD模型组造模第2天肺微小动脉及毛细血管内皮细胞结构基本正常,少数线粒体出现水肿;造模第15天内皮细胞间联结断裂,基底膜不完整,细胞质内细胞器增多,线粒体肿胀,内质网扩张,部分板层体空泡化;造模第28天肺微小动脉内皮细胞细胞质内吞饮小泡增多,线粒体出现水肿或空泡变性,肺毛细血管内皮细胞肿胀,毛细血管腔内可见多形核白细胞堵塞,板层体空泡化明显,内质网扩张明显。结论 COPD形成早期已经出现肺部血管内皮的改变,提示临床上对COPD早期急性肺血管的损伤不可忽视,为更好地制订治疗方案奠定基础。     

Ultrastructural Immunolabeling in the Evaluation, Diagnosis, and Characterization of Neuroendocrine Neoplasms

Neuroendocrine neoplasia represents a heterogenous entity with variable morphologic light microscopic expressions. In many cases a definite diagnosis is easily made by light microscopic examination, but in some cases this does not suffice. In the latter instances, immunocytochemistry, ultrastructural examination, or both are required to diagnose a neuroendocrine neoplasm. However, basing a diagnosis of neuroendocrine neoplasia exclusively on the results obtained from immunocytochemical or ultrastructural evaluation of these tumors may not be entirely accurate in some instances. Ultrastructural immunolabeling plays a key role in accurately defining localization of immunoreactive substances in well-characterized neuroendocrine neoplasms, can assess colocalization of antigenic epitopes, helps define specificity and significance of immunocytochemistry results obtained at the light microscopic level, and is more sensitive than light microscopic immunocytochemistry. Some evolving diagnostic entities can be further characterized by utilization of ultrastructural labeling techniques. Controversies concerning the neuroendocrine nature of electron-dense structures identifiable at the ultrastructural level can be readily and accurately resolved. By providing a way to evaluate combined immunomorphologic parameters, ultrastructural immunogold labeling can settle important questions pertaining to neuroendocrine neoplasia. The present article illustrates a series of cases where the above-mentioned applications were tested.     

Selective zonal change of the renomedullary interstitial cells in hypokalemic rats

Electron microscopic morphometry was undertaken to quantitate the morphological change of the renomedullary interstitial cells (RIC) of hypokalemic rats by using large montages. Two weeks of potassium depletion resulted in an increase of the RIC, which were restricted to the interbundle region of the inner stripe of the outer medulla. The increase of the RIC is characterized by a preferential increase in volume density (+340.0%;P < 0.01) and numerical density (+61.4%;P < 0.01) in the interbundle region but not in the vascular bundle of the inner stripe or in the inner medulla. The increased RIC in the interbundle region of the inner stripe demonstrated an increase of lipid droplets, which are known to contain prostaglandin precursors. The selective zonal change of RIC with increased lipid droplets is a characteristic lesion of hypokalemic rats and suggests an enhanced vasoactive function of RIC associated with hypokalemic nephropathy.     

The effect of adrenomedullin on rats exposed to lead

Adrenomedullin (AdM) was originally discovered as a vasorelaxant peptide. The antioxidative properties of AdM have been reported recently. Through its antioxidative effect, adrenomedullin can protect organs from damage induced by stressors. Lead, commonly detected in air, soil, water and food, is a major source of oxidative stress. The effect of AdM in the liver of rats exposed to lead was investigated. Twenty-four female Wistar rats were divided into four groups: a control group (C), adrenomedullin group (AdM), lead (Pb) group and lead + adrenomedullin (Pb + AdM) group. In the Pb-treated groups, the animals were exposed to lead in drinking water containing 250 ppm PbCl2 for 4 weeks. In the AdM-treated group, the animals received an i.p. injection of AdM (3000 ng kg(-1) body weight) in the third week of lead treatment for 1 week. The activities of catalase (CAT), glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) and the level of malondialdehyde (MDA) were determined in the liver of rats. Histological changes in the liver were examined by light and electron microscopy as well. The MDA levels were increased significantly in the Pb-treated groups, but in the Pb + AdM group the MDA levels were decreased significantly when compared with the Pb group. AdM reduced hepatic damage in the Pb + AdM group, but the difference in the total histopathological scores between the Pb and Pb + AdM groups was not significant. When the results are taken together, it can be concluded that AdM may have protective or compensating effects in lead toxicity.     

Expression of differential immune factors in temporal cortex and cerebellum: The role of α-1-antichymotrypsin,apolipoprotein E,and reactive glia in the progression of Alzheimer's disease

A variety of factors and processes have been implicated in the development and progression of the pathology of Alzheimer's Disease (AD), including amyloid fragment deposition, reactive gliosis, α-1-antichymotrypsin (ACT), and apolipoprotein E (APOE). Carriers of the APOE 4 allele have been shown to have an enhanced risk of developing AD, and the ACT signal peptide A/A genotype may modify the APOEϵ4 risk. The protein products of these genes have been shown to enhance conversion of diffuse β amyloid (Aβ) fibrils, which are found in diffuse plaques, to the fibrillar form found in neuritic plaques. In affected regions of AD brain, ACT and APOE colocalize with Aβ deposits and reactive microglia and astrocytes. We examined the regional distribution of ACT, APOE, and reactive glia in temporal cortex, where neuritic plaques are abundant, and cerebellum (in areas where diffuse plaques but not neuritic plaques accumulate) to examine the relationship of these markers to the deposition of Aβ. In temporal cortex, ACT and APOE staining was localized to plaque-like profiles, reactive astrocytes, and blood vessels; human leukocyte antigen-DR (HLA-DR) and glial fibrillary acidic protein (GFAP) staining revealed focal clusters of reactive microglia and astrocytes. In cerebellum, ACT and APOE immunoreactivity was never localized to plaque-like profiles but was weakly localized to unreactive astrocytes; weak HLA-DR and GFAP immunoreactivity was present on quiescent microglia throughout the cerebellum. The lack of fibrillar amyloid deposits in cerebellum, despite the presence of well-characterized markers thought to mediate the production of Aβ, suggests that this brain region may be lacking certain factors necessary for fibril formation or that the cerebellum responds differently to stimuli that successfully mediate inflammation in affected cortex. J. Comp. Neurol. 396:511–520, 1998. © 1998 Wiley-Liss, Inc.     

Congenital ichthyosiform erythroderma: particulate staining pattern of TGK

A case of late onset non-bullous congenital ichthyosiform erythroderma (CIE) was studied. This patient was not born as a collodion baby and did not have skin abnormalities until 9-10 years of age. She gradually developed erythroderma and fine scales, callosities of her feet, and a mild ectropion. Since recent work has revealed that in the majority of CIE patients, transglutaminase (TGK) is distributed in the cytoplasm of granular cells and horny cells (11), TGK was studied in our case. It was found that TGK was distributed along the cell periphery of horny cells and also in the cytoplasm of granular cells. In the control skins, TGK was stained along the cell periphery of horny cells and granular cells. The marginal band formation was normal. Involucrine and loricrin, the building materials of the marginal band whose-cross-linking is mediated by TGK, were normally stained in the upper epidermis. Cytoplasmic TGK of granular cells and normal development of the marginal band may serve as a helpful diagnostic marker of CIE, particularly because the often confusing collodion baby of lamellar ichthyosis may lack TGK staining and the marginal band altogether.     

Effects of atorvastatin on smoking-induced alveolar injury in rat lungs

Background: Smoking is one of the most serious health care issues worldwide, as one third to one half of all people who smoke eventually use tobacco habitually. Chronic smoke exposure causes airway and lung parenchymal inflammation and the destruction of alveolar cell walls. Statins may have anti-inflammatory effects that would play a role in preventing the cellular damage associated with smoking.Objective: The aim of this study was to investigate whether atorvastatin protects against smoking-induced inflammation in alveolar epithelial type I (ATI) and type II (ATII) cells in the lungs of rats.Methods: Adult male albino Wistar rats (200-250 g) were randomly divided into 3 groups and exposed to cigarette smoke 8 hours per day for 15 days. During that 15-day period, the 2 treatment groups received atorvastatin 0.5 or 1.0 mg/kg/d in 2 mL of methyl cellulose solution and the control group received 2 mL of methyl cellulose solution alone, all via nasogastric catheter. After the 15 days, the lungs were excised and the tissues were examined by transmission electron microscopy.Results: Thirty rats were divided into 3 groups of 10 rats each. All rats survived the 15 days. In the atorvastatin 0.5-mg group, no changes were found in the ATI cells or in the blood-air barrier. In the atorvastatin 1.0-mg group, we observed hyperplasia in the common basal membranes. Hypertrophy, mitochondrial crystolysis (MC), and intracytoplasmic edema (ICE) were detected in the ATI cells in the 1.0-mg group, while chromatin condensation, atrophic appearance, cell shrinkage, and cyto-plasmic vacuolization were observed in the ATII cells. The rough endoplasmic reticulum (rER) tubules of the ATII cells appeared spiral-shaped. In the control group, minimal ICE was detected in the ATI cells. However, microvillus deformation, pseu-dopod formation, edema, mitochondrial swelling, and MC were observed in the ATII cells. We also observed MC, several pinocytic vesicles, and normal rER tubules in the endothelial cells of the control group.Conclusions: The administration of atorvastatin 0.5 mg/kg/d was associated with some attenuation of lung injury caused by smoke inhalation in these rat lungs. However, atorvastatin 1.0 mg/kg/d was associated with lung damage. Future studies are needed to evaluate the dose-response relationship of atorvastatin to smoking-induced alveolar damage.