Large Cytoplasmic Vacuoles Research Articles

Histopathological Characteristics of Kupffer Cells and Ito Cells in the Porcine and Bovine Liver

We previously reported that no Kupffer cells reacted with the antibody against lysozyme, and Ito cells contained a large cytoplasmic vacuole in the feline liver. In this report, we further examined the characteristics of porcine and bovine hepatic non-parenchymal cells. In the liver of both animals, Kupffer cells were positive for lysozyme, and cytoplasmic vacuoles in Ito cells were small. The histopathological characteristics of porcine and bovine hepatic non-parenchymal cells were different from those of the feline liver.

Mutagenicity of diesel exhaust particles mediated by cell–particle interaction in mammalian cells

Diesel exhaust particle (DEP) has been identified as a class 2A human carcinogen and closely related to the increased incidence of respiratory allergy, cardiopulmonary morbidity and mortality, and risk of lung cancer. However, the molecular mechanisms of DEP mutagenicity/carcinogenicity are still largely unknown. In the present study, we focused on the mutagenicity of DEPs in human–hamster hybrid (AL) cells and evaluated the role of cell–particle interaction in mediating mutagenic process. We found that DEPs formed micron-sized aggregates in the medium and located mainly in large cytoplasmic vacuoles of cells by 24h treatment. The cellular granularity was increased by DEP treatment in a dose-dependent manner. DEPs resulted in a dose-dependent increase of mutation yield at CD59 locus in AL cells, while inflicting minimal cytotoxicity. There was a more than two-fold increase of mutation yield at CD59 locus in AL cells exposed to DEPs at a dose of 50μg/ml. Such induction was significantly reduced by concurrent treatment with phagocytosis inhibitors, cytochalasin B and ammonium chloride (p<0.05). These results provided direct evidence that DEPs was mutagenic in mammalian cells and that cell–particle interaction played an essential role in the process.

Relation of hippocampal phospho-SAPK/JNK granules in Alzheimer’s disease and tauopathies to granulovacuolar degeneration bodies

Protein misfolding is a distinguishing feature of a number of neurodegenerative diseases. Accumulation of misfolded protein often results in cellular lesions, the location of lesions correlating with the nature of symptoms. Alzheimer's disease (AD), Progressive Supranuclear Palsy (PSP), Corticobasal Degeneration (CBD) and Pick's Disease (PiD) all present with pathological lesions containing hyperphosphorylated filamentous tau protein; however, the location and type of lesion varies. In addition, granulovacuolar degeneration (GVD) bodies have been reported within hippocampal pyramidal neurons in AD, PSP, CBD and PiD tissue. GVDs are defined as electron-dense granules within double membrane-bound cytoplasmic vacuoles. We have previously reported that the phosphorylated form of stress-activated protein kinase/c-Jun N-terminal kinase (p-SAPK/JNK) accumulates in granules within hippocampal pyramidal cell bodies in AD tissue at the time that hyperphosphorylated tau begins to aggregate into early-stage NFTs. We now report that p-SAPK/JNK granules are found within the hippocampal CA1 region of PSP, CBD and PiD cases as well and that these granules are likely GVD bodies. Quantitatively, p-SAPK/JNK granules and GVDs are found in comparable numbers of CA1 cells. Within cells, p-SAPK/JNK granules are distributed throughout the cytoplasm in a manner similar to the distribution of GVDs and a subset of granules co-localize with GVD markers. Ultrastructurally, p-SAPK/JNK granules are located in large cytoplasmic vacuoles, thereby fitting the definition of a GVD body. With the implication of granular p-SAPK/JNK as a marker of GVDs, our study strongly suggests that a heterogeneous group of proteins form GVDs. The mechanism of GVD formation is therefore an interesting one, and is likely separate and distinct from the mechanism of tau inclusion formation.

Degeneration of the Golgi and neuronal loss in dorsal root ganglia in diabetic BioBreeding/Worcester rats

The aim of this study was to evaluate the nature and extent of neuronal loss in dorsal root ganglia (DRG) in diabetic polyneuropathy. We examined 10-month diabetic BioBreeding/Worcester (BB/Wor) rats with respect to DRG ultrastructure and morphometry, sural nerve morphometry, pro- and anti-apoptotic proteins, the expression of neurotrophic factors and their receptors, and sensory nerve functions. In diabetic rats, DRG neurons decreased to 73% of normal, owing to loss of substance P and calcitonin gene-related peptide-positive neurons. Levels of pro-apoptotic active caspase-3, Bax and low-affinity nerve growth factor (NGF) were increased in DRG. The concentration of anti-apoptotic heat shock protein (HSP) 70 in DRG was decreased, whereas concentrations of Bcl-xl and HSP27 were unaltered. Levels of poly(ADP-ribose) polymerase (PARP) and cleaved PARP were unaltered. Levels of NGF in sciatic nerve and concentrations of the high-affinity NGF receptor, insulin receptor and IGF-I receptor in DRG were significantly decreased. Sensory nerve conduction velocity decreased to 78% of normal. Hyperalgesia increased up to 6 months. Myelinated and unmyelinated fibre numbers of the sural nerve were significantly decreased in diabetic rats. DRG examinations revealed no evidence of apoptosis, mitochondrial changes or abnormalities of the endoplasmic reticulum. Instead, neurons demonstrated progressive vacuolar degenerative changes of the Golgi apparatus, with fragmentation and formation of large cytoplasmic vacuoles. These data show that sustained apoptotic stress is present in DRG of chronically diabetic BB/Wor rats, but fails to proceed to apoptotic cell death. Progressive DRG neuronal loss, particularly of small neurons, occurs in the type 1 diabetic BB/Wor rat. This is associated with neurotrophic withdrawal and progressive degeneration of the Golgi apparatus.

Arsenic trioxide induces not only apoptosis but also autophagic cell death in leukemia cell lines via up-regulation of Beclin-1

Although recent data shows that arsenic trioxide (As 2O 3) is capable of inducing cell death via cell cycle arrest and apoptosis both in acute promyelocytic leukemia (APL) and in non-APL cells, the mechanisms of As 2O 3-mediated cell death are not fully understood. In this study, we investigated the in vitro effects of As 2O 3 on cell growth inhibition and cell death in human T-lymphocytic leukemia and myelodysplastic syndrome (MDS) cell lines. As 2O 3 significantly inhibited the proliferation of Molt-4 and Mutz-1 cells in dose- and time-dependent manner. Autophagic cell death (programmed cell death type II) and apoptosis (programmed cell death type I) were activated together in leukemia cell lines after exposed to As 2O 3. Numerous large cytoplasmic inclusions and vacuoles were observed in As 2O 3-treated cells using electron microscope. Furthermore, 3-methyladenine (an autophagy inhibitor) significantly reduced autophagic cell death and sequentially induced apoptosis. Finally, leukemia cells treated with 4 μM As 2O 3 showed a considerable up-regulation of Beclin-1 (a Bcl-2-interacting protein) expression, which was independent of transcription of mRNA and required protein synthesis. In addition, Molt-4 cells treated with As 2O 3 exhibited the down-regulation of Bax protein expression, suggesting that Bax may be involved in accumulating of Beclin-1 and triggering autophagic cell death in As 2O 3-treated leukemia cells. These results may lead to a better understanding of the mechanism of action of As 2O 3, and provide a suggestion that As 2O 3 may be of therapeutic value for the treatment of patients with human T-lymphocytic leukemia and myelodysplastic syndrome.

Dietary Exposure to 2-Aminoanthracene Induces Morphological and Immunocytochemical Changes in Pancreatic Tissues of Fisher-344 Rats

Toxic chemicals ingested as the result of environmental exposures or other risk factors such as cigarette smoking may increase the risk of developing cancer and other diseases such as diabetes. 2-Aminoanthracene (2-AA) was investigated to determine toxic effects of chronic dietary exposure upon major organ systems including the pancreas. Fisher-344 rats were fed 2-AA (50-100 mg/kg of diet) and euthanized at 14, 30, 63, and 80 days. Growth, tissue histological, immunocytochemical, and clinical pathological end points were examined at each time point. Significantly elevated plasma glucose and glycated hemoglobins and reduced serum protein levels were recognized after 80 days of feeding (100 mg/kg of diet 2-AA group). Similar results were observed in rats exposed to 75 mg/kg of diet but appeared to be absent in the 50-mg/kg group. An unexpected pattern of responses suggestive of diabetic sequelae was observed in a glucose tolerance test conducted during the seventh week. After 63 and 80 days, large cytoplasmic vacuoles in islet cells were observed by light microscopy. In addition, the immunocytochemical study demonstrated beta cell insulin insufficiency at 63 and 80 days. No inflammatory infiltration of the islets was observed. These findings suggest that depletion of secretory granules occurred in the beta cells. Necrotic changes occurred in the acinar cells of the pancreas with increasing duration and dose of 2-AA. The cytological, immunocytochemical, and histological results demonstrate that chronic dietary exposure to 2-amino anthracene alters the endocrine and exocrine pancreas cellular morphology and induces diabetic-like symptoms in the Fisher-344 rat.

Surveillance of nuclear-restricted pre-ribosomes within a subnucleolar region of Saccharomyces cerevisiae.

We previously hypothesized that HEAT-repeat (Huntington, elongation A subunit, TOR) ribosome synthesis factors function in ribosome export. We report that the HEAT-repeat protein Sda1p is a component of late 60S pre-ribosomes and is required for nuclear export of both ribosomal subunits. In strains carrying the ts-lethal sda1-2 mutation, pre-60S particles were rapidly degraded following transfer to 37 degrees C. Polyadenylated forms of the 27S pre-rRNA and the 25S rRNA were detected, suggesting the involvement of the Trf4p/Air/Mtr4p polyadenylation complex (TRAMP). The absence of Trf4p suppressed polyadenylation and stabilized the pre-rRNA and rRNA. The absence of the nuclear exosome component Rrp6p also conferred RNA stabilization, with some hyperadenylation. We conclude that the nuclear-restricted pre-ribosomes are polyadenylated by TRAMP and degraded by the exosome. In sda1-2 strains at 37 degrees C, pre-40S and pre-60S ribosomes initially accumulated in the nucleoplasm, but then strongly concentrated in a subnucleolar focus, together with exosome and TRAMP components. Localization of pre-ribosomes to this focus was lost in sda1-2 strains lacking Trf4p or Rrp6p. We designate this nucleolar focus the No-body and propose that it represents a site of pre-ribosome surveillance.

Excess copper induces structural changes in cultured photosynthetic soybean cells.

Soybean [Glycine max (L.) Merr.] cell suspensions have the capacity to develop tolerance to excess copper, constituting a convenient system for studies on the mechanisms of copper tolerance. The functional cell organisation changes observed in these cell cultures after both short-term (stressed cells) and long-term (acclimated cells) exposure to 10 μm CuSO4 are reported from structural, cytochemical and microanalytical approaches. Cells grown in the presence of 10 μm CuSO4 shared some structural features with untreated cells, such as: (i) a large cytoplasmic vacuole, (ii) chloroplasts along the thin layer of cytoplasm, (iii) nucleus in a peripheral location exhibiting circular-shaped nucleolus and a decondensed chromatin pattern, and (iv) presence of Cajal bodies in the cell nuclei. In addition, cells exposed to 10 μm CuSO4 exhibited important differences compared with untreated cells: (i) chloroplasts displayed rounded shape and smaller size with denser-structured internal membranes, especially in copper-acclimated cells; (ii) no starch granules were found within chloroplasts; (iii) the cytoplasmic vacuole was larger, especially after long-term copper exposure; (iv) the levels of citrate and malate increased. Extracellular dark-coloured deposits with high copper content attached at the outer surface of the cell wall were observed only in cells exposed to a short-term copper stress. Structural cell modifications, mainly affecting chloroplasts, accompanied the short-term copper-induced response and were maintained as stable characters during the period of adaptation to excess copper. Vacuolar changes accompanied the long-term copper response. The results indicate that the first response of soybean cells to excess copper prevents its entry into the cell by immobilising it in the cell wall, and after an adaptive period, acclimation to excess copper may be mainly due to vacuolar sequestration.

Distinguishing Primary and Metastatic Conventional Renal Cell Carcinoma From Other Malignant Neoplasms in Fine-Needle Aspiration Biopsy Specimens

Differentiation of conventional renal cell carcinoma from other malignant neoplasms can be difficult, particularly with the limited sampling in fine-needle aspiration biopsies. Many studies have discussed the features of renal cell carcinoma in fine-needle aspiration biopsy specimens, but the significance of the cytologic features is not known. To define the significant cytologic findings that aid in differentiating renal cell carcinoma from other malignant neoplasms in fine-needle aspiration biopsy specimens. Fine-needle aspiration biopsies from 35 patients with proven primary or metastatic conventional renal cell carcinoma and from 145 patients with proven primary or metastatic non-renal cell carcinoma malignant neoplasms were assessed for the presence or absence of the following cytologic features: the heterogeneous cell population, hemosiderin deposits, small cytoplasmic vacuoles, large cytoplasmic vacuoles, low nuclear-cytoplasmic ratio, prominent nucleoli, intranuclear inclusions, irregular nuclear membranes, and smooth nuclear membranes. Statistical analysis was performed to identify the features significant in distinguishing conventional renal cell carcinoma from non-renal cell carcinoma malignancies. The presence of the heterogeneous cell population, hemosiderin deposits, small cytoplasmic vacuoles, and low nuclear-cytoplasmic ratio were each highly significant in conventional renal cell carcinoma when compared with non-renal cell carcinoma malignant neoplasms (P < .001) using univariate exact analysis. Features that were identified as being predictive of conventional renal cell carcinoma using multivariable logistic regression analysis included heterogeneous cell population, small cytoplasmic vacuoles, and hemosiderin deposits (P < .05). The presence of the heterogeneous cell population, small cytoplasmic vacuoles, hemosiderin deposits, and a low nuclear-cytoplasmic ratio aids in differentiating conventional renal cell carcinoma from other malignant neoplasms, including morphologically similar entities such as hepatocellular carcinoma, in fine-needle aspiration biopsy specimens.

Novel Role of the Small GTPase Rheb: Its Implication in Endocytic Pathway Independent of the Activation of Mammalian Target of Rapamycin

The Ras-homologous GTPase Rheb that is conserved from yeast to human appears to be involved not only in cell growth but also in nutrient uptake. Recent biochemical analysis revealed that tuberous sclerosis complex (TSC), a GTPase-activating protein (GAP), deactivates Rheb and that phosphatidylinositol 3'-kinase (PI3k)-Akt/PKB kinase pathway activates Rheb through inhibition of the GAP-mediated deactivation. Although mammalian target of rapamycin (mTOR) kinase is implicated in the downstream target of Rheb, the direct effector(s) and exact functions of Rheb have not been fully elucidated. Here we identified that Rheb expression in cultured cells induces the formation of large cytoplasmic vacuoles, which are characterized as late endocytic (late endosome- and lysosome-like) components. The vacuole formation required the GTP form of Rheb, but not the activation of the downstream mTOR kinase. These results suggest that Rheb regulates endocytic trafficking pathway independent of the previously identified mTOR pathway. The physiological roles of the two Rheb-dependent signaling pathways are discussed in terms of nutrient uptake and cell growth or cell cycle progression.

Overexpression of mouse GlcNAc-1-phosphotransferase-γ subunit in cells induced an I-cell-like phenotype of mucolipidosis

In a screen of signal peptide-containing proteins from a mouse hypothetical protein library, we identified the mouse UDP-GlcNAc:lysosomal enzyme N-acetylglucosamine-1-phosphotransferase-γ chain (GlcNAc-1-phosphotransferase-γ) (GenBank accession no. AAR19081, HYP36 in this study). The mouse GlcNAc-1-phosphotransferase-γ was localized in the Golgi complex in cells and was expressed ubiquitously in mouse tissues, as shown by fluorescence microscope analysis and a semi-quantitative reverse transcription–polymerase chain reaction (RT-PCR) assay, respectively. Domain analysis showed that the mouse GlcNAc-1-phosphotransferase-γ had a conserved mannose-6-phosphate (M-6-P)-binding domain. Interestingly, we found that overexpression of the mouse GlcNAc-1-phosphotransferase-γ in fibroblast cell line NIH-3T3 induced accumulation of macromolecules, formation of large cytoplasmic vacuoles and decrease of lysosomal enzymes in cells. This phenotype was reminiscent of inclusion cells (I-cells) that were reported in mucolipidosis diseases caused by abnormal sorting of lysosomal proteins. Transient ectopic expression of GlcNAc-1-phosphotransferase-γ in endoplasmic reticulum (ER) induced lowered lysosomal enzyme activity in cells. These results suggested on one hand that GlcNAc-1-phosphotransferase-γ is an essential subunit of the GlcNAc-1-phosphotransferase, and on the other hand, the molecule might not only recognize the substrates of GlcNAc-1-phosphotransferase, but also the lysosomal proteins with M-6-P residuals.

Firm rib mass aspirate from a dog

A 9-year-old intact male Miniature Schnauzer presented laterally recumbent, cachexic, and dehydrated with multiple firm bone masses and a bilaterally enlarged prostate. Fine-needle aspiration of a rib mass revealed numerous basophilic polygonal to fusiform cells predominantly found in small to large clusters. The cells exhibited cytologic criteria of malignancy and infrequently displayed large cytoplasmic vacuoles containing finely- to coarsely-stippled azurophilic material. The cytologic diagnosis was metastatic adenocarcinoma and was suspected to be prostatic or transitional cell in origin because of the azurophilic vacuoles within malignant cells. Gross and histologic findings confirmed the clinical and cytologic diagnosis of prostatic adenocarcinoma with widespread metastasis. Cytochemical and immunohistochemical investigation confirmed glycogen was a component of the vacuolar material. The vacuoles observed in the tumor in this case are not a consistent finding in tumors of the prostate or urinary bladder; however, when associated with an epithelial tumor, they may aid in limiting the differentials of the primary tumor and in the selection of further diagnostics.

Neurological disorder associated with pestivirus infection in sheep in Rio Grande do Sul, Brazil

A two-month-old lamb showing signs of severe neurological disease characterized by muscular tremors, hypermetria, and motor incoordination was submitted to the Veterinary Pathology Laboratory - Universidade Federal do Rio Grande do Sul, Brazil. At necropsy, the major findings were a marked reduction of the size of the cerebellum and bilateral dilatation of the lateral ventricles. Microscopically, areas of cellular disorganization in the cerebellar cortex, reduction of the granular layer of cerebellum associated with decreased density of cells, and the presence of large cytoplasmic vacuoles in the molecular layer were observed. Neurons of the gray matter of the brain and macrophages of the mesenteric lymph nodes stained positively by the immunohistochemistry test using the monoclonal antibody 15C5 against Bovine Viral Diarrhea Virus. Taken together, those results are consistent with a pestivirus infection, either Border Disease Virus (BDV) or BVDV.

Histological organization of the intestine in the crayfish Procambarus clarkii

AbstractSix longitudinal ridges span the length of the intestine in the crayfish Procambarus clarkii. A simple columnar epithelium with tetralaminar cuticle lines the lumen. Folds of the epithelium overlie a dense irregular connective tissue packed with mixed acinar (alveolar) glands. Mucous secretions are probably involved with formation and lubrication of faecal strings; neither the nature nor the role of the serous secretions is immediately apparent. Aggregations of cells with large cytoplasmic vacuoles, called bladder cells, appear in the subepithelial connective tissue near the tops of the intestinal ridges. The bladder cells are suitably positioned to bolster the integrity of the ridges. Striated muscle of the intestine occurs in inner longitudinal and outer circular layers. The inner longitudinal layer consists of six strips, with one strip associated with the base of each intestinal ridge. The outer circular layer is essentially complete, but there are periodic apertures in this layer on the left and right sides of the intestine, providing nerves and haemolymph vessels with access to the interior of the gut. Based on histological features, and consistent with reports on other crayfish, we conclude that the intestine of P. clarkii has a proctodeal (ectodermal) origin.

The ultrastructure of the cyst wall of Giardia lamblia.

Giardiasis is the most common human protozoal infection. In their cystic phase, giardias are protected from the environment by a filamentous cyst wall made up of carbohydrates, proteins, and by two outer membranes separated from the plasma membrane of the parasite by a peripheral space. The present transmission electron microscope observations of G. lamblia cysts of human origin suggest that the extracellular peritrophic space originates from the growth, elongation, and fusion of large cytoplasmic vacuoles. As the large clear vacuoles grew in size, flattening against the inner face of the plasma membrane, they formed a single vacuole that surrounded the body of the parasite, eventually forming two outer membranes. In mature Giardia cysts, the original plasma membrane of the trophozoite becomes the outermost membrane of the cyst wall (CM1). The large vacuoles form a second membrane surrounding the cyst (CM2), and also form a third membrane (CM3), that becomes the new plasma membrane of the trophozoite. During excystation CM1 and CM2 attach to each other and fragment, leaving abundant membrane residues in the peritrophic space. Knowledge of the biochemical composition and functional properties of the complex outer membranous system of G. lamblia cysts here described will be of use to understand the survival of Giardia cysts in the environment, a major factor responsible for the high prevalence of giardiasis worldwide.

Clustering and Redistribution of Late Endocytic Compartments in Response toHelicobacter pyloriVacuolating Toxin

Helicobacter pylori VacA is a secreted protein toxin that may contribute to the pathogenesis of peptic ulcer disease and gastric adenocarcinoma. When added to cultured mammalian cells in the presence of weak bases (e.g., ammonium chloride), VacA induces the formation of large cytoplasmic vacuoles. Here, we report a previously unrecognized capacity of VacA to induce clustering and perinuclear redistribution of late endocytic compartments. In contrast to VacA-induced cell vacuolation, VacA-induced clustering and redistribution of late endocytic compartments are not dependent on the presence of weak bases and are not inhibited by bafilomycin A1. VacA mutant toxins defective in the capacity to form anion-selective membrane channels fail to cause clustering and redistribution. VacA-induced clusters of late endocytic compartments undergo transformation into vacuoles after the addition of ammonium chloride. VacA-induced clustering and redistribution of late endocytic compartments occur in cells expressing wild-type or constitutively active Rab7, but not in cells expressing dominant-negative mutant Rab7. In VacA-treated cells containing clustered late endocytic compartments, overexpression of dominant-negative Rab7 causes reversion to a nonclustered distribution. Redistribution of late endocytic compartments to the perinuclear region requires a functional microtubule cytoskeleton, whereas clustering of these compartments and vacuole formation do not. These data provide evidence that clustering of late endocytic compartments is a critical mechanistic step in the process of VacA-induced cell vacuolation. We speculate that VacA-induced alterations in late endocytic membrane traffic contribute to the capacity of H. pylori to persistently colonize the human gastric mucosa.

Osteogenesis imperfecta in two litters of dachshunds.

A clinical, morphologic, ultrastructural, and genetic study was performed on five rough-coated dachshund semisiblings with osteogenesis imperfecta (OI). Clinical signs consisted of pain, spontaneous bone and teeth fractures, joint hyperlaxity, and reduced bone density on radiography. Primary teeth were extremely thin-walled and brittle. The hallmark of the disease was a severe osteopenia characterized by impairment of lamellar bone formation in the long bones, skull, and vertebral column. No deformity or dwarfism was present. The columns of chondrocytes and primary trabeculae in the epiphyses and metaphyses were histologically normal. An abrupt failure of secondary spongiosa and lamellar bone formation was evident in the medullary and cortical zones in all animals. The few existing trabeculae consisted of woven bone. There was no increase in the number and size of osteoclasts or lacunae. In the teeth, the dentine layers were thin and lacked a tubular pattern. Ultrastructurally, osteoid apposition on bone surfaces was reduced, and small numbers of large cytoplasmic vacuoles were present in a few osteoblasts. Molecular analyses of the collagen type I-encoding genes COL1A1 and COL1A2 revealed several nucleotide differences compared with the published canine sequences but were not significant for OI. Therefore, OI in these Dachshund litters was characterized by a severe, generalized osteopenia and dentinopenia. This pattern of reduced bone formation is suggestive of defective production of collagen type I.

Gastric cell apoptosis and H. pylori: has the main function of VacA finally been identified?

The vacuolating cytotoxin VacA is one of the most important virulence factors of Helicobacter pylori, a bacterium causing severe gastric diseases such as ulcers and cancer. VacA forms large cytoplasmic vacuoles in cultured cells, although its effects on host cells in vivo remain to be elucidated. Three independent groups have reported that VacA induces epithelial cell apoptosis. In particular, a recent study has demonstrated unambiguously the role of VacA in inducing epithelial gastric cell apoptosis.

The Effect of Ovariectomy and Estradiol on Rabbit Bladder Smooth Muscle Contraction and Morphology

The bladder can be considered a target organ for the actions of estrogen. Decreases in circulating estrogen after menopause have been associated with bladder dysfunctions, including incontinence and detrusor instability. We determined the effects of estrogen on rabbit bladder contractile function and morphology. Female New Zealand White rabbits were ovariectomized or sham operated and treated with vehicle or estradiol (1 mg/kg weekly) for 5 weeks. Serum estradiol concentration was monitored every 2 weeks. After treatment each rabbit was anesthetized, the bladder was catheterized, cystometry was performed, and the bladder was removed for contractile and morphological studies. Apoptosis in paraffin embedded rabbit bladder tissue was detected using in situ end-labeling, specifically terminal deoxynucleotidyl-transferase nick end labeling or the TUNEL assay. Ovariectomy resulted in a 50% decrease in circulating estrogen and estradiol treatment resulted in a 5-fold increase. Ovariectomy had no significant effects on bladder capacity, micturition pressure or bladder weight; whereas estradiol treatment resulted in significant increases in bladder capacity and bladder weight. Ovariectomy resulted in a decreased rate of tension generation in response to field stimulation, carbachol and KCl. Estradiol resulted in increased contractile responses to FS and carbachol, and an increased rate of tension generation for carbachol and KCl. Histologically ovariectomy resulted in significant urothelial apoptosis, which was not present in the sham operated or estradiol treated groups. Estradiol treatment resulted in the appearance of large cytoplasmic vacuoles in the urothelium and significant smooth muscle hypertrophy. These findings demonstrate that bladder function and structure can be significantly affected by modulating the circulating estrogen level. In addition, estrogen given in pharmacological doses can have a significant hypertrophic effect on bladder smooth muscle, resulting in increased contractile function.

Calf Mass in an 11-Year-Old Girl

Calf Mass in an 11-Year-Old Girl