Scanning electron microscopy of podocytes of the renal glomerulus of rats with nephrotoxic serum nephritis

Summary Nephrotoxic serum nephritis was produced in rats by intraperitoneal injections of rabbit nephrotoxic serum. Heterologous and autologous phases of nephritis were demonstrated by immunofluorescence and ultrastructural studies. Scanning electron microscopy showed changes in the surface of the podocytes, swelling of the arm-like cytoplasmic processes, and disappearance of the pedicles. The podocyte alterations are discussed.     

Rabbit lung macrophages stimulate platelets in vitro as observed by density-gradient centrifugation and transmission electron microscopy

Jørgensen L, Nilsen GJ, Perry DW, Mustard JF, Kinlough-Rathbone RL. Rabbit lung macrophages stimulate platelets in vitro as observed by density-gradient centrifugation and transmission electron microscopy. Scand J Clin Lab Invest 1993; 53: 711-724.

Both platelets and macrophages play a role in the pathogenesis of atherosclerosis. To examine whether they may interact and, if they do, to elucidate the mechanisms of such an interaction, suspensions of the two cell types from rabbits were mixed together, then subjected to Stractan density-gradient centrifugation and transmission electron microscopy. Suspensions of only one cell type served as controls.

When otherwise unstimulated platelets and macrophages came into contact with each other, the platelets became less dense. Ultrastructurally, the platelets underwent shape changes without losing their granules, and were often arranged around the macrophages like a rosette. The processes of the macrophages became elongated. ADP caused a similar shift in platelet density and, when the cell types were together, increased this shift. With ADP the resetting was abolished, but platelet aggregates were found to be in superficial contact with the macrophages. With thrombin the contact between the platelet aggregates and macrophages was close.

Addition of platelet antagonists showed that the shift in platelet density and the rosetting upon contact with macrophages are dependent on divalent cations. Neither ADP, nor thrombin, nor PAF seem to be involved in the reactions.     

Morphological expressions of antibiotic synergism against Pseudomonas aeruginosa as observed by scanning electron microscopy.

Antibiotic-induced changes in Pseudomonas aeruginosa were observed by means of a scanning electron microscope. Seven frequent and five less frequent morphological changes were noted. The frequent changes were: (i) elongation; (ii) chain formation; (iii) nub formation; (iv) spheroplasts; (v) surface holes or pits; (vi) super-elongation; and (vii) increased filamentation. The less frequent changes were: (i) rounded ends; (ii) streptococcal forms; (ii) stalked nubs; (iv) surface bulges; and (v) convoluted surfaces. A morphological equivalent of antibiotic synergism was found in which changes were noted due to synergistic combinations of antibiotics that were not observed when the antibiotics were used alone or when a nonsynergistic combination of antibiotics was used.     

Analysis of urinary sediment by transmission electron microscopy. An innovative approach to diagnosis and prognosis in renal disease

Urinary sediment TEM is capable of unequivocally demonstrating renal tubule cells and distinguishing them from urinary tract epithelial cells. The renal tubule cells and the accompaniments including myeloid bodies, inflammatory cells, or fibrin permit, in a particular clinical setting, synthesis of a meaningful renal diagnosis. Sequential TEM sediment studies can clarify ambiguities in diagnosis. Precisely, when much difficulty is experienced in distinguishing ATN from aminoglycoside nephrotoxicity in a patient with sepsis who has received aminoglycoside, urinary sediment TEM can facilitate the differential diagnosis with confidence. In another clinical setting, such as hypersensitivity acute interstitial nephritis, TEM urinary sediment has an irrevocable place by exhibiting the characteristic eosinophil granules that will confirm the above diagnosis, or deny it when they are absent. The morphologic features in the renal tubule cells in the sediment reflect similar changes in the tubular cells in renal tissue. Therefore, the severity of tubular changes are commensurate with the clinical outcome in terms of renal function recovery, need of dialysis, and mortality. The degree of correlation is significant. Thus, slight or no TEM sediment tubular changes signifies a good prospect for renal function recovery and low or no mortality. Conversely, severe tubular changes in the TEM sediment denote persistent renal failure accompanied by high mortality. Furthermore, the most severe tubular changes, found in hepatorenal syndrome, are consistent with its dismal prognosis.     

Comparative morphology of granulocytes collected by three methods of leukapheresis. A light microscopy and transmission electron microscopy study

The morphology of granulocytes collected by continuous-flow centrifugation (CFC), discontinuous-flow centrifugation (DFC), and continuous-flow filtration (CFF) was investigated in 18 healthy donors by means of light microscopy and transmission electron microscopy. Light microscopy study of semithin sections of granulocytes collected by CFC and DFC showed minimal morphologic abnormalities, compared to granulocytes procured by CFF. Ultrastructural study of granulocytes procured by CFF showed more conspicuous qualitative and quantitative abnormalities (the most prominent being "microvilli," degranulation, and bazarre chromatin) than in granulocytes obtained by the other two methods. Controls showed that the bulk of CFF-cell abnormalities was due to the "tapping" of the filters. Factors such as the mechanical compression (plasma extractor) used in DFC method, donor pretreatment with anticoagulants and steroids, hydroxyethyl starch, and duration of leukapheresis scarcely influenced granulocyte morphology.     

L—精氨酸对实验性急性肾功能衰竭大鼠的治疗作用观察

目的：探讨Ｌ精氨酸（ＬＡｒｇ）对实验性急性肾功能衰竭（ＡＲＦ）大鼠的治疗作用。方法：ＳＤ大鼠随机分为３组，即蒸馏水组（Ｃ组）、顺铂组（ＣＰ组）和ＬＡｒｇ加顺铂组（Ａ组），静脉给药，观察一氧化氮（ＮＯ）合成底物ＬＡｒｇ对顺铂所致ＡＲＦ大鼠肾功能及肾组织形态学的影响。结果：①Ａ组用药后第４日、６日、８日和１０日的血肌酐（ＳＣｒ）及血尿素氮（ＢＵＮ）均显著低于同期ＣＰ组的ＳＣｒ和ＢＵＮ（Ｐ均＜０．０５）；②Ａ组肾组织形态学改变较ＣＰ组明显改善。结论：ＬＡｒｇ对实验性ＡＲＦ有明显保护作用，可能主要与其促使ＮＯ合成增加、改善肾血流动力学有关。     

肾活检标本351例电镜检查病理诊断分析

目的客观评估电镜检查在肾活检病理诊断中的作用。方法对351例肾活检标本先后进行光镜免疫荧光联合检查以及电镜检查,统计最终病理诊断类型的分布,并对电镜检查在肾活检病理诊断中的作用进行分析,比较电镜检查与光镜免疫荧光联合检查对肾活检病理最终诊断的影响。结果①最终诊断为肾小球疾病的占绝大多数(97.7%),以IgA肾病(18.8%)、薄基底膜肾病(8.8%)、肾小球微小病变(8.3%)、膜性肾病(8.3%)、糖尿病肾病(7.1%)多见;②电镜检查对肾活检病理诊断起决定诊断作用的病例占21.9%,起修正补充作用的病例占23.7%,而起验证作用占54.4%;③电镜检查对45.6%的肾活检最终病理诊断提供有价值信息,而光镜免疫荧光联合检查对54.4%的病例可独立诊断(χ2=5.476,P<0.05)。结论进行电镜检查对肾活检标本病理诊断非常必要,应该常规留取标本进行电镜检查。     

Ultrasound-induced damage of veins in pig ears, as revealed by scanning electron microscopy

Pig ear veins have been treated in situ with ultrasound at a frequency of 750 kHz and intensity of 1.5 W cm-2 (spatial average) during which the temperature in the surrounding tissues rose to 52-54 degrees C. The veins were examined by scanning electron microscopy. Gaps developed between the endothelial cells, which showed many fine perforations in their membranes. Extensive blood clots were observed in which erythrocytes had become more spherical and showed damaged membranes. Effects on membranes were also found with HeLa cells heated to 50 degrees C, and have been previously described by others in heat-treated blood vessels.     

Neurite density from magnetic resonance diffusion measurements at ultrahigh field: Comparison with light microscopy and electron microscopy

Due to its unique sensitivity to tissue microstructure, diffusion-weighted magnetic resonance imaging (MRI) has found many applications in clinical and fundamental science. With few exceptions, a more precise correspondence between physiological or biophysical properties and the obtained diffusion parameters remain uncertain due to lack of specificity. In this work, we address this problem by comparing diffusion parameters of a recently introduced model for water diffusion in brain matter to light microscopy and quantitative electron microscopy. Specifically, we compare diffusion model predictions of neurite density in rats to optical myelin staining intensity and stereological estimation of neurite volume fraction using electron microscopy. We find that the diffusion model describes data better and that its parameters show stronger correlation with optical and electron microscopy, and thus reflect myelinated neurite density better than the more frequently used diffusion tensor imaging (DTI) and cumulant expansion methods. Furthermore, the estimated neurite orientations capture dendritic architecture more faithfully than DTI diffusion ellipsoids.