Effect of boron on the ultrastructure of parathyrocytes and atrial cardiomyocytes

Ultrastructural shifts in parathyrocytes and atrial cardiomyocytes induced by long-term treatment with boron-containing water (250 mg/liter) were found against the background of boron accumulation. These changes are indicative of enhanced secretory activity of these cells. It is hypothesized that boron modulates the effect of parathyroid hormone and atrial natriuretic factor and the rate calcium-sodium exchange. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 124, No. 7, pp. 111–114, July, 1997     

Ultrastructural changes in the cerebral cortex after transcranial micropolarization

An electron-microscopic investigation of the cerebral cortex of cats and monkeys after transcranial micropolarization (TCMP) revealed ultrastructural changes the severity of which depended on the intensity of the current and the duration of its action. In the focus of exposure the current acted directly on the brain tissue, but the cerebral cortical cells differed in their sensitivity to different conditions of TCMP. The most reactive tissue was the glia, followed by the bodies of neurons and synaptic structures. In areas of brain remote from the focus of TCMP the ultrastructural organization of the synapses was principally altered. The morphological changes discovered were not pathological.Laboratory of Physiological Mechanisms of Memory Control, Institute of Experimental Medicine, Academy of Medical Sciences of the USSR, Leningrad. (Presented by Academician of the Academy of Medical Sciences of the USSR N. P. Bekhtereva.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 86, No. 12, pp. 737–739, December, 1978.     

Ultrastructural localization of voltage-sensitive sodium channels using [I]α scorpion toxin

The distribution of α scorpion toxin (α-ScTx) receptors was examined in differentiated mouse neuroblastoma cell cultures (N IE 115 clone) by electron microscope autoradiography using [¹²⁵I]α-ScTx. This neurotoxin binds specifically to voltage-sensitive sodium channels, slowing down the inactivation of the sodium permeability. Quantitative analysis demonstrated that only plasma membranes were labelled. The α-ScTx receptors seemed to be randomly dispersed on both cell bodies and cell processes. Microvilli protruding from the cell bodies carried more sodium channels than other parts of the membrane. The specific binding site density for α-ScTx varied from 4 (cell body membrane) to 13 (cell process membrane) per square micrometer.     

Neurotoxic action of 2,5-hexanedione on the autonomic nervous system: ultrastructural and functional alterations in the rat sympathetic superior cervical ganglion

In rats treated for 14 days with 2,5-hexanedione, the efficiency of ganglionic transmission was markedly reduced whereas only faint ultrastructural changes occurred in a few preganglionic fibers; evident signs of axonal pathology were observed on the 30th day of treatment. Choline acetyltransferase activity and acetylcholine formation showed no alteration at any time. The autonomic system is affected early during 2,5-hexanedione neuropathy, functional changes being more marked than morphological lesions.     

煤尘引起肺组织反应的超微结构观察

从超微结构方面研究了动物模型中三个煤种的煤尘与肺巨噬细胞的相互作用及其作用下的肺组织反应。煤尘在肺巨噬细胞中发生了诸如粉尘粒子边缘模糊,呈云雾状,电子密度不均,半壁消融等改变,但各煤种反应强度不一。巨噬细胞保持完好,细胞器增生,出现模一层结构,褐煤尘组肺组织自始至终出现显著的Ⅱ型细胞反应。煤尘同样能引起浆细胞反应及一些胶原纤维增生。吞噬了煤尘的退化的肺巨噬细胞有向纤维细胞转化的倾向。     

A quantitative ultrastructural study of the pinealocyte of the chipmunk (Tamias striatus) during the daytime and at night

Day-night differences in the areas of granular endoplasmic reticulum, Golgi apparatus, dense-core vesicles, and lysosomelike bodies were analyzed morphometrically in the pinealocytes of the chipmunk. The area of lysosomelike bodies was greater at night and lower during the daytime. In contrast, the areas of granular endoplasmic reticulum and dense-core vesicles were greater during daytime and lower at night. Our observations suggest the existence of 24-hour rhythms in the areas of these structures, perhaps indicative of a pineal rhythm in secretion, whether indolic or peptidergic.     

Ultrastructural localization of LH-RH-immunoreactive synapses in the hamster accessory olfactory bulb

Electron microscopic immunocytochemistry was used to localize luteinizing hormone-releasing (LH-RH) immunoreactivity within the male golden hamster accessory olfactory bulb. Two LH-RH-immunoreactive fiber populations were identified in the accessory olfactory bulb. A superficial system of immunoreactive axons was localized to the vomeronasal nerve and glomerular layers, and a periventricular system appeared in granule cell and periventricular layers. LH-RH-immunoreactive varicosities were observed to contain large reactive vesicles (80-120 nm) as well as a variable degree of cytoplasmic reaction product. Additionally, small vesicles with unreactive lumens and mitochondria were often present. Intravaricose segments of immunoreactive fibers invariably displayed fewer reactive vesicles than did varicosities. Within both glomerular and periventricular layers, some LH-RH-immunoreactive varicosities were observed to form asymmetric contacts characterized by prominent postjunctional densities. In the glomerular layer, these junctions could be identified as synaptic by several features. The presence of LH-RH-immunoreactivity in presynaptic elements supports a neuromodulatory role for LH-RH. As the accessory olfactory system is critically involved in the initiation of mating behavior of the male golden hamster, LH-RH-immunoreactive synapses in the accessory olfactory bulb may function to regulate reproductive behavior.     

Developmental potential and ultrastructural injuries of metaphase II (MII) mouse oocytes after slow freezing or vitrification

Purpose: The purpose of this study was to determine the developmental ability and ultrastructure of MII mouse oocytes after cryopreservation by slow freezing or vitrification.Methods: Ovulated MII mouse oocytes were allocated to slow frozen, vitrified and control groups. Oocytes in the slow frozen and vitrified groups were cryopreserved using 1,2 propandiol (PROH) and ethylene glycol (EG) respectively as cryoprotectants. After thawing, the surviving MII oocytes in both cryopreserved groups and the control group were inseminated and their developmental ability was compared. The ultrastructure of MII oocytes in both cryopreserved groups was assessed immediately after thawing and 10 h post insemination at the pronuclear stage, and compared with that of the control group.Results: The survival rates were nearly identical in both cryopreserved groups. The fertilization rates were also identical and comparable to that of the control group. The further development of vitrified oocytes was similar to that of the control oocytes, whereas it was severely limited in the slow-frozen oocytes. In the slow-frozen MII oocytes, the intermediate filaments were destroyed and the oolemma and microvilli were also modified. At the pronuclear stage deterioration of mitochondria and the presence of numerous vacuoles were also observed within the ooplasm. In the vitrified MII oocytes, the intermediate filaments were the only structures affected and these cytoskeletal elements were reorganized at the pronuclear stage.Conclusions: Vitrification results in less ultrastructural damage and better post fertilization development of MII mouse oocytes than slow freezing.     

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。