The experimental opening and resealing of occluding junctions in monolayers cultured MDCK cells (epithelioid renal origin) was explored by measuring changes the electrical resistance across monolayer freeze-fracture electron microscopy. As natural epithelia, function as permeability barriers specifically depends on extracellular Ca++ concentration fails if this ion is replaced Mg++ or Ba++. removal addition EGTA to bathing medium opened reduced transepithelial resistance. Resealing achieved...

MDCK cells form uninterrupted monolayers and make occluding junctions similar to those of natural epithelia. This aricle explores the relationship between these cytoskeleton by combining studies on distribution microfilaments microtubules with effect drugs, such as colchicines cytochalasin B, degree tightness junctions. To study tightness, were prepared plating mylon disks coated collagen. Disks mounted flat sheets two Lucite chambers, sealing capacity was evaluated measuring electrical...

When MDCK cells are cultured in monolayers, they synthesize, assemble, and seal occluding junctions that limit the paracellular route. These processes may be impaired by inhibitors of protein synthesis but not RNA. Once established, confer to monolayer an overall electrical resistance 80-600 omega . cm2. At microscopical level, individual have large variations along perimeter a given cell. This agrees with images freeze-fracture electron microscopy where network junction varies abruptly from...

Invasion of human tissues by the parasitic protozoan Entamoeba histolytica is a multistep process involving, as first step, recognition surface molecules on target amebas or trophozoites. This initial contact followed release proteolytic and other activities that lyse cells degrade extracellular matrix. In diseases, well in certain cancers, interaction invasive organisms with fibronectin (FN) through specific receptors has been shown to be step cell recognition. Interaction FN triggers...

Invasiveness of Entamoeba histolytica strains that cause acute amoebiasis is characterized by aggressive behavior associated with cell motility and actin function. Analysis genes from E. was initiated devising methods for the isolation biologically active nucleic acids, which allowed preparation cDNA genomic DNA libraries. actin-encoding cDNAs clones have been isolated libraries prepared virulent HM1:IMSS strain using a heterologous probe. Nucleotide sequence analysis three independent one...

A 125-kD surface antigen of Entamoeba histolytica is recognized by 73% immune sera from patients with amoebic liver abscesses. Using pooled human a cDNA clone (lambda cM17) encoding this (M17) has been isolated lambda gt11 expression library the virulent stain E. HM1:IMSS. Monospecific antibodies, purified binding to phage lysate cM17, and mAb FA7 reacted exclusively Western blot analysis. Surface cap formation are observed patient sera, monospecific antiserum, FA7. Corresponding genomic...

The formation of blisters is a transient phenomenon that led Dr. Leighton to describe its observation with time-lapse photography in the MDCK monolayer "gently boiling oatmeal." One may ask why it and most areas are momentarily not blistering. observations discussed this article indicate (a) at blister, junctions really tight; (b) when transported fluid allowed escape through permeable support, also tight, but (c) support impermeable allow ouabain peroxidase through. This suggests that, if...

Actin has been identified and purified partially from trophozoites of Entamoeba histolytica HMI-IMSS by a procedure that minimizes proteolysis. In cellular extracts, actin would copolymerize with muscle actin, but not bind to DNase I or form microfilaments. Fractionation the extracts DEAE-cellulose Sephadex G-150 chromatography yielded rabbit skeletal polymerize alone into long filaments at 24 degrees C upon addition 100 mM KC1 2 MgCl2. These are cold-stable will depolymerize 4 in 1 h....

A 220-kilodalton (kDa) protein with lectin properties was isolated from Entamoeba histolytica strain HM1:IMSS and purified by Sepharose 4B chromatography electroelution 5% SDS-polyacrylamide gels. The contains 9% carbohydrate weight; is rich in hydrophobic residues; very immunogenic mice, hamsters, rabbits. binds to fixed monolayers of MDCK cells inhibits trophozoite attachment the cultured cells. 220-kDa agglutinates human erythrocytes, agglutination inhibited micro molar concentrations...

A 130,000 Mr protein was isolated from human platelets by sequential DEAE-Sephacel and Sepharose Cl-4B chromatography. Low shear viscometric measurements showed that the enriched after chromatography inhibited actin polymerization. This effect somewhat greater in presence of EGTA than calcium. Further purification resulted a complete loss this inhibitory effect. Studies with fluorescent detected no nucleation or "+" end capping activity either DEAE-Sephacel- Cl-4B-purified vinculin....

Antibodies were prepared against a 220-kilodalton (kDa) protein partially purified by Sepharose 4B chromatography of Entamoeba histolytica strain HM38:IMSS homogenates, and the was found to have lectin properties. The antibodies specifically recognized this in trophozoite homogenates. Immunologically related molecules with same molecular weight identified polyclonal strains HMI:IMSS, invadens, Laredo. Six monoclonal only 220-kDa present HM38 HMl, result indicating presence similar epitopes...

Gelsolin is a 90,000-mol-wt Ca2+-binding, actin-associated protein that can nucleate actin filament growth, sever filaments, and cap barbed ends. Brevin closely related 92,000-mol-wt plasma with similar properties. has been reported to be localized on filaments in stress fibers, cardiac skeletal muscle I-bands, cellular regions where are known concentrated. Previous localization studies have used sera or antibody preparations contain brevin. Using purified brevin-free IgG IgA monoclonal...

Amoebic liver abscess (ALA) is the most important extraintestinal complication of Entamoeba histolytica infection. development causes severe destruction tissue concomitant with a strong inflammatory reaction. We analyse in situ expression TNF-α, IFN-γ, IL-1β, 1L-8 and IL-10 at different stages ALA susceptible animal model. Results showed that after inoculation, neutrophils (PMN) some macrophages infiltrated were positive for TNF-α IFN-γ acute phase amoeba The presence these cytokines was...

A vertical polyacrylamide gradient gel (3% to 7%) was designed facilitate the electrophoretic resolution and classification of isoenzyme patterns Entamoeba histolytica isolates. The following enzyme systems were used: phosphoglucomutase (PGM), hexokinase (HX), glucosephosphate isomerase (GPI), malate dehydrogenase (ME). modifications in procedure sample preparation allowed reproducible comparison axenic, monoxenic, mixed cultures E. isolated from humans. clear distinction obtained gels,...

ABSTRACT In vitro formation of a functional MDCK cell monolayer requires the dynamic participation cytoskeleton. Cell shape, contacts and polarity, as well transepithelial electric resistance (TER), are actively modified during this differentiation process. We studied distribution rearrangement cytokeratin, vimentin actin filaments that occur in concomitant with synthesis phosphorylation these proteins. Cells cultured for short time suspension, subconfluent or early confluent cells, showed...

Introduction: Primary retroperitoneal mucinous cystic tumors with borderline malignancy are rare neoplasms of uncertain histopathogenesis few cases reported in the literature. Histologically, these an analogous counterpart to more common ovarian tumor. A microinvasive component may contribute higher probabilities recurrence and poor prognosis, while presence various mutations, particularly KRAS GNAS exons, could have therapeutic relevance future. Case Report: Imaging studies a 42-year-old...