Bilateral retinoblastoma in a male patient with an X; 13 translocation: evidence for silencing of the RB1 gene by the spreading of X inactivation.
Explore the source record for details and available documents.
Chromosome Banding↗
Biomedical subjects
C Booth
Publications and source records attributed to C Booth.
Delayed adjuvant therapy with the 21-aminosteroid U74006F and the anion channel blocker L644-711 does not improve outcome following thrombolytic therapy in a rabbit model of thromboembolic stroke.
BACKGROUND: Both the 21-aminosteroid U74006F, a potent inhibitor of lipid peroxidation, and L644-711, an anion channel blocker that inhibits both neutrophil and astrocyte function, have been previously shown to reduce brain injury in pretreatment paradigms of cerebral ischemia. It was therefore of interest to examine the effect of these agents in combination, when given on a delayed basis as adjuvants to thrombolytic therapy in a rabbit model of thromboembolic stroke. METHODS: Animals were mechanically ventilated and arterial blood gases controlled. Core and brain temperature, intracranial pressure, and mean arterial pressure were continuously monitored. Regional cerebral blood flow and hematocrit were measured hourly. Blood samples were taken to measure neutrophil (aggregation and chemiluminescence) and platelet (aggregation) activity. Following delivery of an autologous clot via the carotid artery, all experiments were continued for an 8-hour period. U74006F (3 mg/kg I.V.) and L644,711 (12 mg/kg I.V.) or their vehicle control (n = 8, each group) were given 3.5 hours following autologous clot embolization. Both groups received tissue-type plasminogen activator (t-PA) (6.3 mg/kg I.V.), beginning 4 hours following thromboembolic stroke and continuing over a 2-hour infusion period. Infarct size was determined following staining and image analysis. RESULTS: In the L644,711/U74006F group, neutrophil chemiluminescence was reduced following drug therapy; however, there were no significant differences between groups regarding infarct size (50.3 +/- 8.7 vs. 49.9 +/- 10.6, treatment vs. t-PA control, mean +/- SEM), or in regional cerebral blood flow or intracranial pressure over time. CONCLUSIONS: It is concluded that prolonged (3.5 hours) delay of the initiation of therapy with the anion channel blocker L644,711 and the 21-aminosteroid U74006F fails to further reduce brain injury when given in combination with tissue plasminogen activator in a rabbit model of thromboembolic stroke.
Animals↗
The role of radiation-induced and spontaneous apoptosis in the homeostasis of the gastrointestinal epithelium: a brief review.
Until fairly recently, investigations into the control of cell production (proliferation) have been the mainstay of studies into the maintenance of mucosal homeostasis and general integrity. However, in addition to proliferation, it is now increasingly evident that programmed cell death, specifically that form of programmed cell death known as apoptosis, is an equally, if not more important, mechanism of regulating mucosal cell number. This review will concentrate on the significance of damage (radiation) induced and spontaneous apoptosis in the maintenance of intestinal epithelial stem cell number and integrity, and its probable link to the level of cancer incidence in the small intestine and colon.
Animals↗
The intestinal epithelial stem cell: the mucosal governor.
All epithelial cells in the small and large intestine are thought to originate from stem cells located towards the base of the crypts of Lieberkühn. To-date, there are no specific intestinal stem cell markers, hence stem cell properties can only be inferred. A range of experimental techniques have been employed including cell position mapping, radiation regeneration (clonogenic) assays, chimeric and transgenic mice. This review discusses the implications of experiments performed using these techniques in order to deduce the number, location and functional properties of stem cells. Stem cell homeostasis is maintained by cell proliferation and death 'through apoptosis'. The various growth and matrix factors and genes which may control these processes, and be important for stem cell function, are discussed along with their carcinogenic and clinical implications.
Animals↗
Reconstitution of human urothelium from monolayer cultures.
PURPOSE: We established a 3-dimensional organ culture model of urinary tract tissue in which to study the effects of seeding cultured urothelial cells onto de-epithelialized urothelial stroma. MATERIALS AND METHODS: Normal human urinary tract tissues were placed in organ culture or used to establish urothelial cell cultures. At passage 2 cell cultures were harvested and used to reconstitute autologous organ cultures by seeding onto de-epithelialized stroma. Organ cultures were harvested at intervals and analyzed by immunohistology with a panel of antibodies against differentiation associated antigens, cytokeratins, cell adhesion molecules, extracellular matrix components and proliferation associated antigens. RESULTS: Human urothelial tissues were maintained in organ culture for at least 18 weeks and they retained a transitional epithelial morphology with expression of normal in situ antigenic characteristics. Within 2 weeks of reconstitution recombined organ cultures formed a stratified, polarized, transitional-like neo-epithelium that expressed many of the phenotypic and differentiated characteristics of normal tissue. Basement membrane formed at sites of direct contact between urothelial cells and stroma. After an initial stabilization period the proliferation rate of the urothelium of intact and reconstituted organ cultures decreased to the low turnover rate characteristic of normal urothelium in situ, indicating that the cells were responsive to normal growth regulatory controls. CONCLUSIONS: Normal human urothelial cells, which express a proliferative nondifferentiated phenotype in monolayer culture, retain the capacity to differentiate and reform a slow turnover, stratified transitional epithelium.
Cell Adhesion↗
Stromal and vascular invasion in an human in vitro bladder cancer model.
In transitional cell carcinoma (TCC) of the urinary bladder, disease spread may occur through local invasion of the bladder wall and/or via hematogenous dissemination. Although the metastatic phenotype is well studied, little is known about the mechanisms that determine and regulate secondary dispersion via stromal and vascular routes. The aim of this study was to develop an in vitro system to study TCC invasion using normal human urinary tract stroma in organ culture. Human de-epithelialized urinary tract stromas were seeded with established human TCC cell lines (RT4, RT112, and EJ) and maintained in organ culture at an air-liquid interface for up to 8 weeks. The composite tissues were analyzed immunohistochemically using antibodies to a proliferation-associated antigen, cell adhesion molecules, extracellular matrix components, and cytokeratin isotypes. The phenotype of TCC cell lines maintained as monolayer cultures were compared with the composite tissues to assess the regulatory effects of the stroma. On a normal urothelial stroma, the TCC cell lines proliferated and underwent a degree of differentiation related to the grade of the original tumor. RT4 cells formed a stratified epithelium with low proliferation, some characteristics of urothelial differentiation, and no evidence of stromal invasion over the 8-week culture period. RT12 cells formed a stratified epithelium with limited differentiation and by 2 weeks showed intravasation of the subepithelial capillary bed. Anaplastic EJ cells did not stratify but diffusely invaded the stromal matrix and the superficial vasculature. In conclusion, the urothelial stroma can support cytodifferentiation in vitro and influence the behavior of malignant TCC cells. The model has application for determining genetic and epigenetic factors that influence whether a tumor progresses by local and/or hematogenous spread. Furthermore, it may offer a useful approach in evaluating prognostic and diagnostic markers and strategies for preventing invasion.
Antibodies, Monoclonal↗
Peroxynitrite augments fMLP-stimulated chemiluminescence by neutrophils in human whole blood.
The neutrophil respiratory burst was examined by the technique of luminol-dependent chemiluminescence (LDCL) triggered by submaximal concentrations of N-formyl-methionyl-leucyl-phenylalanine (fMLP) in diluted whole blood. We sought to identify the chemical species responsible for LDCL in whole blood, to examine the role of leukotriene B4 (LTB4) and other arachidonic acid metabolites as mediators of the fMLP signaling pathway, and to investigate the effect of peroxynitrite on this response. Both sodium azide and taurine significantly inhibited LDCL (93% inhibition with 100 microM azide, 52% inhibition with 10 mM taurine). More modest inhibition was seen with superoxide dismutase (SOD), catalase, the nitric oxide synthase inhibitor monomethyl-L-arginine (L-NMMA), and with inhibitors of the cyclooxygenase (indomethacin), lipoxygenase (AA-861; no effect), and cytochrome P-450 (SKF 525-A) pathways of arachidonic acid metabolism. The nitric oxide donor SIN-1 (1-100 microM) and peroxynitrite (10-300 microM) also augmented fMLP-induced LDCL. The augmentation seen with peroxynitrite and SIN-1 was attenuated by SOD. Despite the increase in LDCL, peroxynitrite caused a dose-related inhibition of fMLP-stimulated LTB4 release. In summary, our results indicate that (1) LDCL elicited by fMLP in diluted whole blood appears primarily mediated by hypochlorous acid derived from myeloperoxidase; (2) pretreatment with the nitric oxide donor SIN-1 or with peroxynitrite augments LDCL; and (3) LTB4 release does not contribute to fMLP-stimulated LDCL or in the modulation of LDCL by SIN-1 or peroxynitrite.
Antioxidants↗
The effect of oral antiplatelet agents on tissue plasminogen activator-mediated thrombolysis in a rabbit model of thromboembolic stroke.
OBJECTIVE: The success of thrombolytic therapy in acute stroke relies on timely reperfusion. The current study examines the efficacy of antiplatelet agents as adjuvants for thrombolytic therapy. METHODS: Using an established rabbit model of clot embolization and a randomized blinded design, rabbits (n = 8 in each group) were orally pretreated daily for 5 days with adjuvant aspirin (1 mg/kg of body weight or 20 mg/kg), ticlopidine (100 mg/kg), or vehicle (sodium carbonate). On the 6th day, tissue plasminogen activator (6.3 mg/kg administered intravenously over 2 h), was initiated 1 hour after embolization. RESULTS: In all groups, cerebral blood flow (CBF) was reduced to < 10 ml/100 g/min immediately after clot embolization. After the initiation of tissue plasminogen activator (t-PA), there was significant restoration of CBF in the control (t-PA only) and ticlopidine groups (P < 0.05) only. Restoration of CBF generally correlated with brain infarct size (percent hemisphere, mean +/- standard error of the mean), which was 18.0 +/- 7.0 in the t-PA only group versus 11.0 +/- 3.3, 26.5 +/- 5.8, and 21.5 +/- 3.4 in the ticlopidine, low-dose aspirin, and high-dose aspirin groups, respectively (ticlopidine versus aspirin, P < 0.05). Clot lysis was identical in the control and ticlopidine groups, with 6 of 8 animals demonstrating complete clot lysis. Aspirin antagonized clot lysis in a dose-related manner, with low-and high-dose aspirin groups noting clot lysis in four of eight and two of eight animals, respectively. CONCLUSIONS: Pretreatment with ticlopidine significantly reduced brain infarct size when compared with aspirin treatment (P < 0.05). Moreover, whereas ticlopidine treatment did not affect clot lysis or CBF relative to t-PA alone, aspirin therapy resulted in antagonism of clot lysis and was associated with a more modest restoration of blood flow. This study provides a background for a more comprehensive understanding of the balance of thrombogenicity and thrombolysis and may assist in the development of novel therapies to expedite cerebrovascular patency and reduce ischemic and reperfusion-mediated neuronal injury.
Animals↗
Calcium chloride; a reminder.
Explore the source record for details and available documents.
Calcium Chloride↗
Identification of a case of maternal uniparental disomy of chromosome 10 associated with confined placental mosaicism.
We report a case of maternal uniparental disomy of chromosome 10 discovered after chorionic villus sampling (CVS). Direct preparations revealed mosaic trisomy 10, while cultured CVS cells, as well as amniotic fluid cells, showed only a normal 46,XY complement. DNA analysis using microsatellite markers showed both chromosomes 10 to have been inherited from the mother. The pregnancy was complicated by polyhydramnios. A phenotypically normal male infant of appropriate size was delivered by Caesarean section at 41 weeks' gestation. Since only the direct preparations showed trisomy 10, this case illustrates the importance of CVS direct preparations in the detection of pregnancies at risk of uniparental disomy (UPD). Although the increased frequency of confined placental mosaicism (CPM) diagnosed when direct preparations are performed has been viewed negatively, identification of both CPM and UPD may have biological and clinical significance for a pregnancy. Even though only a single case of maternal disomy 10 is reported here, the apparently normal phenotype provides evidence that there are no major imprinted loci on chromosome 10 that affect in utero growth and development. However, other potential effects such as mental retardation will require long-term follow-up of this as well as additional cases.
Adult↗
Growth factor regulation of proliferation in primary cultures of small intestinal epithelium.
Although the intestinal epithelium is one of the most rapidly renewing tissues, little is known about the major growth factors that control the rate of cell replacement and migration. Recently, a primary culture model has been described for the developing rat small intestinal epithelium, which permits epithelial growth while maintaining interactions with associated stromal cells, thereby possessing several contextual advantages over established cell lines (Evans et al., 1992). We have used this model to begin to determine the factors that may be involved in controlling intestinal epithelial cell proliferation. Under the conditions examined, no single growth factor promoted exclusive proliferation of epithelial cells; stromal cell proliferation was also apparent. The most potent stimulators of epithelial proliferation were insulin and insulin-like growth factor 1 (IGF-1). These factors also appeared to inhibit migration of the epithelial cells. 5-10 ng/ml EGF, 5-20 ng/ml TGF alpha, and 10-20 ng/ml PDGF also slightly increased epithelial cell numbers. Cell proliferation was inhibited by 0.1 ng/ml TGF beta-1. In Dulbecco's modified Eagle's medium (DMEM) containing 0.25 IU/ml insulin, glucose levels of 2-3 g/liter permitted epithelial growth with limited expansion of the stromal cell population. Higher levels of glucose further stimulated the nonepithelial cell types. Transferrin was also a potent stimulator of both cell types.
Animals↗
Preparation and characterization of poly(epsilon-caprolactone) polymer blends for the delivery of proteins.
A series of ternary blend matrices, based on high- and low-molecular-weight poly(epsilon-caprolactone) (PCL) and a poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) block copolymer (Synperonic L61), has been developed for the delivery of proteins. The inclusion of Synperonic L61 served to enhance the water content of the matrix available for protein diffusion. Blends comprising high-molecular-weight PCL (PCLH) and Synperonic L61 alone were found by scanning electron microscopy to be incompatible over a wide composition range. The addition of a low-molecular-weight PCL (PCLL) enhanced compatibility of the polymeric components. Analysis of the dynamic mechanical and thermal properties of these blends showed a significant shift in the glass transition temperature of the material (-38 to -55 degrees C), as the weight fraction of Synperonic L61 increased to 30 wt%, indicative of limited miscibility of the components in the non-crystalline phase. All ternary blended matrices showed a higher degree of hydration relative to homogeneous PCLH. The maximum water content could be modified by adjusting the weight fraction of Synperonic L61 in the blend. The rate of release of a model protein, bovine serum albumin (BSA), from matrices containing Synperonic L61 was considerably higher than that from PCLH and PCLH/PCLL alone. Analysis of the release mechanisms of BSA from these matrices suggested that, whilst diffusion was the predominant mode of protein transport, the elution of Synperonic L61 from blended matrices during the dissolution caused a notable deviation from Fickian control.
Biocompatible Materials↗
Solubilisation of drugs in micellar systems studied by eluent gel permeation chromatography.
PURPOSE: The purpose of the study was to investigate the potential of a chromatographic method which is based on elution gel chromatography (EGPC) in the study of solubilisation of drugs in micellar solutions. METHODS: The EGPC method differs from conventional GPC in the use of a solution of the associating surfactant as eluent (rather than solvent) and the injection of a small volume of solution of different concentration (or alternatively injection of solvent alone) to probe the association equilibrium in the eluent. The technique was applied to a study of the solubilisation of selected drugs in aqueous micellar solutions of a triblock copolymer (Synperonic-PE F127) composed of oxyethylene [E, OCH2CH2] and oxypropylene [P, OCH2CH(CH3)] units with nominal molecular formula E98P67E98. RESULTS: EGPC curves were obtained showing vacancy peaks at the elution volumes of the drugs, clearly demonstrating their solubilisation. In addition, the micelle-molecule equilibrium of the copolymer surfactant could be monitored at all times. Quantitative determination of the partition of solute between micelles and solvent phase was not possible due to the incomplete conversion of molecules to micelles in solutions of the selected copolymer. CONCLUSIONS: The EGPC technique provides evidence for the solubilisation of the drugs in aqueous solutions of Synperonic F127; a more thorough assessment of its potential for quantitative measurement of solubilisation requires the use of a surfactant which is wholly (or at least mainly) in the micellar state under the conditions of use.
Adsorption↗
Effects of IL-11 on the growth of intestinal epithelial cells in vitro.
The network of interacting factors that control proliferation in the intestinal epithelium is largely unknown. Recently, IL-11 was found to protect animals from lethal doses of cytotoxic agents. Part of this protective action was ascribed to a reduced level of damage in the intestinal epithelium. Whether this was due to a direct effect on epithelial cell cycle progression was unclear. We have addressed this question in vitro and found that IL-11 reversibly inhibited proliferation in untransformed small intestinal IEC18 cells. However, IL-11 did not inhibit transformed SW620 or HT29 colonic cell lines. IL-6 behaved in a similar manner to IL-11. Thus, these results suggest that IL-11 may be an ideal therapy adjuvant, protecting normal cells and further, these results suggest that IL-11 may be involved in the normal growth controls in the intestinal epithelium. The inhibitory response evoked by IL-11 is lost during carcinogenic transformation.
Animals↗
Acute myeloid leukemia and myelodysplasia following intensive chemotherapy for breast cancer.
Two major classes of therapy-related acute myeloid leukemias (t-AML) and myelodysplastic syndromes (t-MDS) have been described following the use of conventional doses of alkylating agents and epipodophyllotoxins. They are characterized by distinct clinical presentations and chromosomal abnormalities. We report 2 cases of t-AML and 1 case of t-MDS in 3 out of 36 women who underwent high-dose chemotherapy and attempted ABMT for breast cancer. Two patients developed t-AML 4 and 8 months following the initiation of high-dose chemotherapy with or without ABMT. The third patient developed t-MDS 23 months following dose-intensive chemotherapy and ABMT. Cytogenetic studies of the marrow metaphase chromosomes from the two patients who developed t-AML, including FISH analysis in 1 patient, showed a t(9;11)(p22ng,q23) abnormal chromosome 6 (ring chromosome). Neither patient had a preleukemic phase. Cytogenetic studies from the third patient who developed t-MDS showed abnormalities of chromosome 5 (-5) and a derivative of chromosome 17. The use of multiple chemotherapeutic agents in all 3 patients makes it difficult to attribute the development of these cases of t-MDS/t-AML to a single chemotherapeutic agent. The possible role of dose-intensive chemotherapy in the development of these secondary malignancies is discussed.
Acute Disease↗
The isolation and culture of adult mouse colonic epithelium.
A technique is described for the reproducible primary culture of colonic epithelium from adult mice. A collagenase-dispase digestion technique (adapted form Evans et al. 1992) is used to release the epithelium, followed by differential sedimentation to produce a high purity crypt preparation with maintained structural integrity and minimal mesenchymal contamination. The crypt units attach to collagen coated plastic within 24 h and the epithelial cells quickly begin to migrate outwards producing a monolayer surrounding the attached crypts. Electron microscopy revealed that the migrating epithelial cells possessed both desmosomes and microvilli. Proliferation in the colony supports the outward migration of cells until the migratory cells of adjacent colonies connect and a confluent monolayer begins to form. Proliferation is routinely maintained for 10 days (although cultures have now been maintained without subculturing for 35 days) and is demonstrated by increased cell numbers in spite of continuous cell loss into the culture media. Culture growth is enhanced by increasing concentrations of fetal calf and mouse serum and EGF but does not appear to respond significantly to added transferrin. Growth is also stimulated by a murine small intestinal extract thought to contain a potentially novel growth factor or cocktail of factors. This culture model has considerable potential for studies on growth factor control of this carcinoma susceptible tissue and its differentiated function as well as studies into the mechanisms of carinogenesis.
Animals↗
A potent stimulator of small intestinal cell proliferation extracted by simple diffusion from intact irradiated intestine: in vitro studies.
The epithelium lining the small intestine is one of the most rapidly proliferating body tissues yet it rarely develops cancers. The proliferation, migration and differentiation of the stem cell progeny appears to be under very strict control. After 8 Gy gamma irradiation the murine epithelium contains surviving stem cells from which the epithelium rapidly and effectively regenerates, presumably in response to stimulatory signals, and then returns to steady state conditions after overshoots in proliferation. Here we describe the isolation and preliminary characterisation in vitro of a potent stimulatory extract obtained by diffusion from intact murine small intestine, post-irradiation. In addition to in vivo responses the extract stimulates intestinal epithelial lines very effectively, most notably the rat IEC 18 line where it can replace the serum requirement. The extent of the induced increase in proliferation could not be reproduced by any other single growth factor tested. Preliminary evidence suggests the extract contains either a potent stimulatory cocktail of factors or a novel intestinal growth factor(s).
Animals↗
Expression of pokeweed lectin binding in murine intestinal Paneth cells.
Pokeweed (Phytolacca americana) lectin was found to stain the secretory granules in epithelial Paneth cells of small intestine in mice and rats. The distribution of Paneth cells stained with this lectin was identical to that obtained by another immunohistochemical marker for lysozyme. However, in comparison with other immunohistochemical markers, Pokeweed lectin is a more robust method for identifying Paneth cells in histological sections and for studying their secretory granules. Co-expression of the Pokeweed lectin binding sites in some oligomucous cells within the crypts suggested a close developmental link between these two cell types. Only one other non-epithelial cell type was stained by this lectin, and these were migratory lymphocytes found within the villus epithelium and lamina propria. Approximately 20% of these lymphocyte cells were also positive for the expression of CD3+. Pokeweed lectin was therefore used to study changes in the frequency of Paneth cells and intra-epithelial lymphocytes in normal and immunologically compromised animals (following infection with a parasite worm Trichuris muris and in a model of graft-versus-host rejection). This study confirmed that the population of Paneth cells turns over slowly even during conditions of inflammation.
Animals↗