No currently defined imaging techniques can reliably distinguish between oncocytoma and epithelial malignant lesions with oncocytic features in the kidney; therefore, patients must undergo resection or, in certain circumstances, biopsy to definitively establish diagnosis. Immunohistochemical staining for CD10 and CD3, evaluation of the staining pattern and intensity, and relevant morphologic appearance are helpful diagnostic tools in discriminating between renal cell carcinoma with oncocytic features and renal oncocytoma. Electron microscopy confirms different ultrastructural components of each neoplastic cell type and correlates with immunohistochemical findings. Accurate determination of the tumor origin would allow for the use of limited nephron sparing and laparoscopic surgical approaches to treat appropriately.

Background Our objective was to assess the histological changes in mammary glands of the female Wistar-Furth rat as a result of low dose exposure to N-nitrosomethylurea (NMU). Methods Groups of 30–40 virgin female rats of between 49–58 days old received a single injection of 10, 20, 30 or 50 mg NMU/kg body weight (BW). A group of 10 control rats received 0.9% NaCl solution only. The formation of palpable mammary gland tumors was assessed weekly and, upon sacrifice at 12, 22 and 25–30 weeks after treatment, we performed a comprehensive histological analysis of all mammary gland lesions and tumors. Results Alongside the predicted increase in tumor number and decrease in tumor latency with increasing NMU dose, we observed a number of microscopic lesions and other epithelial abnormalities in the mammary glands for all NMU doses. Two types of non-neoplastic histological changes were observed in rats exposed to 10 or 20 mg NMU/kg BW: namely, (i) an increase in the number of acinar structures often accompanied by secretion into the lumen which is normally associated with pregnancy and lactation, and (ii) an increase in the number of epithelial cells sloughed into the lumen of the epithelial ducts. Conclusion This study establishes a baseline for low-dose exposure and defines the histological features in the mammary gland resulting from NMU exposure. Furthermore, this system provides an ideal platform for evaluating the relative susceptibility of animals protected from, or predisposed to, developing cancer through environmental influences.

Humans are routinely exposed to bisphenol-A (BPA), an estrogenic compound that leaches from consumer products. Given the sensitivity of the developing organism to hormones, exposure of fetuses and infants is a concern. Here, CD-1 mice were exposed to environmentally relevant doses of BPA during gestation and the lactational period (gestational day 8 through postnatal day 16). At 3, 9 and 12–15 months of age, mammary glands from exposed offspring were examined for structural changes. BPA-exposed females demonstrated altered mammary phenotypes including the appearance of alveolar buds. Additionally, intraductal hyperplasias were observed exclusively in BPA-exposed females. These lesions had the appearance of “beaded” ducts, with epithelial cells present inside the ductal lumen and increased proliferation indexes compared to normal ducts. Similar structures have also been observed following exposure to other estrogens. These results are further evidence that perinatal BPA exposure can alter the morphology of the rodent mammary gland in adulthood.

Metanephric adenoma is a benign renal neoplasm with morphologic features similar to those of malignant renal neoplasms, such as papillary renal cell carcinoma (RCC) and Wilms' tumor. Different methods have been used to distinguish between metanephric adenoma and papillary RCC and Wilms' tumor. However, some techniques are not always available, such as certain immunohistochemical stains, cytogenetics, molecular genetics, and electron microscopy. In the current study, we compared the expression of S100 protein in 15 cases of metanephric adenoma, 10 cases of Wilms' tumor, and 13 cases of papillary RCC. Our results revealed strong expression of S100 proteins in all cases of metanephric adenoma, weak expression in two cases of Wilms' tumor, and no expression in any of the cases of papillary RCC. These findings indicate that S100 could be a useful and accessible tool for the diagnosis of metanephric adenoma.

Infantile osteopetrosis with neuronal storage disease is a rare lysosomal storage disorder. It is an autosomal recessive disease that is associated with mutations in the OSTM1 and chloride channel ClCN-7genes. So far mutations in the OSTM1 gene have been identified in only 8 patients. To date, the clinical and morphological features of nine patients with infantile osteopetrosis with neuronal storage have been reported, but no ultrastructural findings of skin have been described in these patients. Skin biopsy is a cost-effective tool for the diagnosis of lysosomal storage disease. The purpose of this report is to define the ultrastructure of affected cells seen in skin biopsies of 2 boys whose mutation of OSTM1 has been characterized. The children presented in infancy with severe osteopetrosis and neurological deficiencies whose predominant symptoms were marked cerebral atrophy, decreased myelinization, and severe central nervous system involvement. Because of the difficulties in distinguishing this disorder from some lysosomal storage diseases such as mucopolysaccharidosis that have both neurological and skeletal abnormalities, the authors elected to examine skin biopsies from these children. Ultrastructural examination revealed the presence of swollen unmyelinated axons containing spheroids, reduced numbers of myelinated axons, and the presence of secondary lysosomes in Schwann cells containing lipofuscin. This study demonstrates that electron microscopy of skin biopsy is a useful diagnostic method to identify patients with clinical features of osteopetrosis with neuronal storage disease.

In this report, the authors summarize their 19-year experience with over 200 biochemically proven cases of lysosomal storage diseases using electron microscopic screening of more than 950 skin biopsies. They found that electron microscopy (EM) is a highly sensitive, efficient, cost-effective, and rapid diagnostic screening tool for evaluation of lysosomal storage diseases in skin biopsies. Although EM is more expensive than a single enzyme assay, it can exclude more than 90% of cases in which lysosomal storage disease is being considered. EM is critical for diagnosis of neuronal ceroid lipofuscinosis and mucolipidosis IV and is the most cost-effective screening tool in patients with previously unrecognized storage diseases.

Systemic lupus erythematosus (SLE) is characterized by the production of autoantibodies that are frequently directed against nucleic acid-associated antigens. To better understand how B cells reactive with such antigens are regulated, we generated a model system in which heavy and light chain genes encoding 564 immunoglobulin have been targeted to the heavy and light chain loci of the nonautoimmune C57BL/6 mouse strain. This antibody recognizes RNA, single-stranded DNA, and nucleosomes. We show that B cells expressing this immunoglobulin were activated, producing class-switched autoantibody in vivo despite the apparently normal induction of anergy. This autoantibody production was largely dependent on Toll-like receptor 7 (TLR7). We further show that production of these autoantibodies was sufficient to cause kidney pathology in these mice. These results demonstrate that the particular threat of nucleic acid-containing autoantigens lies in their ability to bind both antigen receptor and TLR7.

Exposure of the fetus to excess estrogen is believed to increase the risk of developing breast cancer during adult life. Fetal exposure to low doses of the xenoestrogen bisphenol A resulted in long-lasting effects in the mouse mammary gland that were manifested during adult life. It enhanced sensitivity to estradiol, decreased apoptosis, increased the number of progesterone receptor-positive epithelial cells at puberty and increased lateral branching at 4 months of age. We now report that fetal exposure to 2.5, 25, 250 and 1000μg bisphenol A/kg body weight/day induces the development of ductal hyperplasias and carcinoma in situ at postnatal day 50 and 95 in rats. These highly proliferative lesions have an increased number of estrogen receptor-α positive cells. Thus, fetal bisphenol A exposure is sufficient to induce the development of preneoplastic and neoplastic lesions in the mammary gland in the absence of any additional treatment aimed at increasing tumor development.

A complex network of interactions between the stroma, the extracellular matrix and the epithelium drives mammary gland development and function. Two main assumptions in chemical carcinogenesis of the mammary gland have been that carcinogens induce neoplasia by causing mutations in the DNA of the epithelial cells and that the alterations of tissue architecture observed in neoplasms are a consequence of this primary mutational event. Here, we use a rat mammary tissue recombination model and the chemical carcinogen N-nitrosomethylurea (NMU) to determine whether the primary target of the carcinogen is the epithelium, the stroma or both tissue compartments. Mammary epithelial cells were exposed in vitro either to the carcinogen or vehicle before being transplanted into the cleared fat pads of rats exposed to carcinogen or vehicle. We observed that neoplastic transformation of these mammary epithelial cells occurred only when the stroma was exposed in vivo to NMU, regardless of whether or not the epithelial cells were exposed to the carcinogen. Mammary epithelial cells exposed in vitro to the carcinogen formed phenotypically normal ducts when injected into a non-treated stroma. Mutation in the Ha-ras-1 gene did not correlate with initiation of neoplasia. Not only was it often found in both cleared mammary fat pads of vehicle-treated animals and intact mammary glands of untreated animals, but it was also absent in some tumors. Our results suggest that the stroma is a crucial target of the carcinogen and that mutation in the Ha-ras-1 gene is neither necessary nor sufficient for tumor initiation.

Conventional peritoneal dialysis (PD) fluids are known to inhibit polymorphonuclear cells (PMN) phagocytosis, oxidative burst and enzyme release. However, the relative contributions of apoptosis and/or necrosis to this dysfunction have not been examined. We investigated the effects of osmolality, glucose concentration and heat-sterilization of PD fluids on necrosis and apoptosis of PMN. Polymorphonuclear cells were isolated from 8 healthy volunteers and exposed to different PD fluids for four hours. PMN were then double-stained with Hoechst 33342 and propidium iodide to study the proportion of viable, apoptotic and necrotic cells. Transmission electron microscopy (TEM) was performed to confirm the results obtained with flow cytometry. The fluids studied were conventionally heat-sterilized 1.5% Dianeal(R) (1.5%D), conventionally heat-sterilized 4.25% Dianeal(R) (4.25%D), 1.5%D in which the osmolality was increased to that of 4.25%D by adding mannitol (1.5%D + M), a filter-sterilized version of 4.25%D (4.25%D-F) and a 1.1% amino acid PD fluid (AA) (Nutrineal(R) PD4). All PD fluids had their pH equilibrated (pH = 7.4) by the addition of sodium bicarbonate. Compared to PMN exposed to culture medium, a significantly higher proportion of necrosis was observed in PMN exposed to 1.5%D (P = 0.04). The 4.25%D induced greater necrosis than 1.5%D (P = 0.001), and the 4.25%D also induced significantly more necrosis (P = 0.002) compared to 4.25%D-F. These data suggest that the consequences of heat-sterilization, rather than high glucose concentration are responsible for the necrosis observed. Indeed, the proportion of necrotic PMN with 4.25%D-F was not significantly different from 1.5%D. The 1.5%D + M and AA induced significantly more apoptosis compared to 1.5%D (P = 0.006 and P < 0.05, respectively), suggesting that apoptosis can be induced by the high osmolality of PD fluids. However, 1.5%D+/-M also induced significantly more apoptosis (P = 0.007) compared to 4.25%D-F. This suggests that the apoptosis effect is specific for the osmolyte present in PD fluids, and that mannitol and amino acids induce more apoptosis than glucose. In summary. the different non-physiological components of conventional PD fluids evaluated in this study had a differential effect on PMN survival. Heat sterilization of high glucose-containing PD fluids was associated predominantly with necrosis of PMN, and high osmolality with apoptosis.

To investigate the capacity of lupus autoAb to produce glomerular immune deposits (ID) and nephritis, 24 murine monoclonal (m) anti-DNA antibodies (Ab), derived from either MRL-lpr/lpr, SNF1 or NZB lupus-prone mice and selected based on properties shared with nephritogenic Ig, were administered i.p. (as hybridomas) and i.v. (as purified Ig) to normal mice; at least four mice/mAb were evaluated. Three general patterns of immune deposit formation (IDF) were observed: extracellular ID within glomeruli (+/- blood vessels, N = 8); intranuclear ID (N = 5); or minimal or no ID (N = 11). The four MRL m anti-DNA Ab that produced significant extracellular ID demonstrated different disease profiles including: (a) mesangial and subendothelial ID with anti-basement membrane staining, associated with proliferative glomerulonephritis, PMN infiltration, and proteinuria; (b) diffuse fine granular mesangial and extraglomerular vascular ID, associated with proliferative glomerulonephritis and proteinuria; (c) dense intramembranous ID and intraluminal ID, associated with capillary wall thickening, mesangial interposition and expansion, aneurysmal dilatation and intraluminal occlusion of glomerular capillary loops, and heavy proteinuria; and (d) mesangial and extraglomerular vascular ID, associated with mild segmental mesangial expansion, without proteinuria. These MRL mAb were derived from four different mice, and they had variable pIs and isotypes. They all cross reacted with multiple autoantigens (autoAg), however, their autoAg binding profiles were distinguishable. Among the SNF1 derived mAb, four produced histologically and clinically indistinguishable disease characterized by diffuse mesangial and capillary wall ID, associated with cellular proliferation/infiltration and proteinuria. Three of the four mAb were derived from the same mouse and were clonally related; they were: IgG2b with SWR allotype, relatively cationic, highly cross reactive with similar Ag binding patterns, idiotypically related and encoded by identical VH and nearly identical VL sequences. We conclude that both the capacity of lupus autoAb to form ID and the location of IDF are dependent on properties unique to individual Ig. The results also indicate that the Ag binding region of the autoAb is influential in this process, and they suggest that multiple Ab-Ag interactions contribute to IDF in individuals with lupus nephritis. Furthermore, these observations raise the possibility that the pathologic and clinical abnormalities resulting from these interactions are influenced by the location of IDF, and that the dominant interaction, in a given individual, may be highly influential in the phenotypic expression of nephritis.

Although it has been observed that DNA has a high binding affinity for the glomerular basement membrane (GBM) in vitro, glomerular localization of DNA has not been demonstrated in vivo. To evaluate this possibility, after injection of 125I ssDNA of varying molecular weight (mol. wt.) to normal mice, we measured glomerular levels of DNA in vivo. Following administration of 2 mg of 125I high mol. wt. purified single stranded(ss) DNA (2-6 kilobases; 0.7-2.0 x 10(6)D) to normal mice, DNA was not detected in glomeruli, despite measurable blood levels of DNA for 72 h. In contrast, after injection of 280 micrograms of low mol. wt. 125ssDNA (160-200 bases; mol. wt. = 5.3-6.6 x 10(4)D) to normal mice, glomerular localization was observed throughout the 24-h study period despite relatively low 125IssDNA blood levels. The results of these studies indicate that free circulating DNA can bind to sites within glomeruli in vivo, and that the size of DNA is crucial for this interaction. Since low mol. wt. DNA is present in the plasma of patients with active lupus, these findings raise the possibility that DNA may bind to glomeruli and serve as a planted antigen for in situ immune complex formation with circulating anti-DNA antibodies.

We have compared the pattern of lectin staining with the ultrastructural features of kidneys from normal cats and 19 cats with 6 different lysosomal storage diseases. The diseases studied include GM1 and GM2 gangliosidosis, mucopolysaccharidosis (MPS)-I and MPS-VI, sphingomyelinlipidosis (i.e., Niemann-Pick disease) and mannosidosis. Ten different biotinylated lectins were used as histochemical probes for carbohydrate residues and avidin-biotin-peroxidase complex as visualant.Concanavalia ensiformis agglutinin (Con A) stained mesangial cells in all storage diseases but GM1, epithelial cells in sphingomyelin-lipidosis and mannosidosis, endothelial cells in GM1 and mannosidosis and Bowman’s capsule cells in all but GM2.Griffonia simplicifolia agglutinin I (GS-I) stained the glomerular endothelium in all six diseases, but not in control kidneys.Ricinus communis agglutinin-I (RCA-I) stained the glomerular epithelium only in GM1 and MPS-I. Succinylated wheat germ agglutinin (SWGA) stained the glomerular endothelium and epithelium in mannosidosis, and the glomerular epithelium and Bowman’s capsule in MPS-I. Ultrastructure studies demonstrated an accumulation of oligosaccharides in cases of mannosidosis and GM1 gangliosidosis, a mixture of oligosaccharides and lipids in MPS-I, MPS-VI and GM2 gangliosidosis and only lipid storage in sphingomyelin lipidosis. These studies show that morphologic and histochemical changes are manifested in some kidney cell types in lysosomal storage diseases, even though the enzyme deficiency occurs in all cell types. Furthermore, we show that the nature of the undegraded stored material is complex and that other factors, such as rate of membrane turn over, membrane composition, and cell function may influence the amount and nature of the “stored” material.

with Concanavalia ensiformis (Con A), Triticum vulgaris (WGA), and succinyl-WGA (S-WGA), while �3-mannosi- dosis cells did not stain with any of the lectins used. In fucosidosis the affected cells stained with Ulex europeus-I (UEA-I), while sialisidosis-affected cells stained with WGA, and in three cases with Arachis bypogea (PNA). This study indicates that lectin histochemistry provides a reliable spe- cific diagnostic pattern for some glycoprotein storage dis- eases using a simple and inexpensive method.

We have studied the ultrastructure of glycocalyx at the luminal surface of normal and diseased urothelium from humans and rats with ruthenium red staining. A correlation between the thickness and staining intensity of the glycocalyx and the surface topography of the luminal surface was observed. An intensely stained thick glycocalyx was associated with prominent surface microvilli seen in the following conditions in humans : some control urothelium, inverted papilloma, well and moderately differentiated transitional cell carcinomas and mucin producing adenocarcinomas. These changes were also present in rats with FANFT-induced preneoplastic and neoplastic changes. A thin glycocalyx was associated with a scalloped luminal surface containing asymmetric unit membrane plaques and was found in some control human urothelium and in normal rat urothelium. A thin glycocalyx was also associated with the relatively smooth surface seen in poorly differentiated transitional cell carcinomas as well as in some mucin producing adenocarcinomas. We suggest that urothelial glycocalyx, as demonstrated by ruthenium red staining, correlates with the luminal surface topography rather than specific pathological condition of the bladder.

Neoplastic and non-neoplastic tissue specimens from ten patients with primary adenocarcinoma of the urinary bladder were examined. Most of these tumors were associated with either foci of transitional cell carcinoma and/or with glandular metaplasia of the bladder epithelium. The mucin produced by the neoplastic cells was PAS, alcian blue, mucicarmine, PB/KOH/PAS, and RPB/KOH/PAS-positive. ABH isoantigens of these tumors were not always deleted. Ultrastructurally, the neoplastic cells resembled goblet cells. Their plasma membrane had numerous microvilli with prominent glycocalyx. Proliferation and attenuation of tight junctions were noted. The gap junctions were few and small. Two types of desmosomes were found. The ultrastructural features of the neoplastic cells were attributed in part to the malignant transformation and in part to the direction of their differentiation. We have not observed any distinctive morphologic, histochemical, immunologic or ultrastructural features that might be diagnostic for these adenocarcinomas.