News - Part 74

Helicobacter pylori and endothelial adhesion molecules: RESULTS

LPS concentrations in the five HPEs ranged from 0.65 EU/mL to 4.16 EU/mL. Final LPS concentrations in medium containing 10% HPE ranged from 0.065 EU/mL to 0.416 EU/mL. All strains were positive for both cagA and vacA genes. Unstimulated HUVEC constitutively expressed ICAM-1 but little VCAM-1 and E-selectin (Figure 1). Coincubation with 20 U/mL of IL-1p (positive control) for 6 h significantly (P<0.05 versus unstimulated) upregulated surface expression of ICAM-1, VCAM-1 and E-selectin on HUVEC. Read more »

Helicobacter pylori and endothelial adhesion molecules: ELISA (Part 2)

molecule-inducing factor in HPECharacterization of HPE

Gel filtration was used to estimate the molecular weight of the adhesion molecule-inducing factor in HPE from NCTC11637. Freeze-dried extract (10 mg) mixed with 1.5 mL of 150 mM NaCl was eluted through a HiPrep Sephacryl S-100 HR column (Pharmacia Fine Chemicals, USA), with collection of 2 mL fractions. Each fraction (10%) was estimated for adhesion molecule-induction activity. Data were expressed as a ratio of each sample OD to control OD (IL-1P). Read more »

Helicobacter pylori and endothelial adhesion molecules: ELISA (Part 1)

ELISA was used to assess the binding of mAbs to the endothelial cell monolayers. Confluent HUVEC monolayers prepared in 96-well plates were coincubated with interleukin (IL)-1P (20 U/mL), Escherichia coli lipopolysaccharide (LPS) (0.74 EU/mL, Sigma Chemical Co, USA), or HPE (10%) for 6 h at 37°C in a CO2 incubator. Immediately after pretreatment, the cells were fixed by the addition of 1% paraformaldehyde in PBS for 15 min at room temperature. Read more »

Helicobacter pylori and endothelial adhesion molecules: HPE (Part 2)

Endothelial cellsThe resulting supernatant, the initial water extract with no preservatives added, was stored at -20°C until needed. Before use, the extract was brought to room temperature and centrifuged at 18,000 rpm (38,700 g) for 20 min, and the pellet was discarded. The supernatant was then passed through a 0.2 micron Acrodisc (Gelman Science, USA) syringe-adapted filter. This procedure removed much of the high molecular weight complex material, which consisted mainly of membrane vesicles and intact flagellae. Read more »

Helicobacter pylori and endothelial adhesion molecules: HPE (Part 1)

Because adherence between endothelial cells and H pylori, a noninvasive bacterium, cannot occur within gastric mucosa, it is very important to estimate activation of endothelial cells by the stimulation of some substance secreted or released from H pylori. In the present study, we examined whether H pylori water extract (HPE) induces the upregulation of three important adhesion molecules, ICAM-1, VCAM-1 and E-selectin, on cultured human umbilical vein endothelial cells (HUVEC). We also analyzed the nature of the substances which mediate such upregulation. Read more »

Helicobacter pylori and endothelial adhesion molecules

Helicobacter pylori infectionHelicobacter pylori infection, well known as the cause of chronic active gastritis and peptic ulcer, is associated with gastric mucosal injury. Mucosal infiltration by leukocytes is seen histologically in H pylori infection . Infiltration by leukocytes into gastric mucosa is associated with interactions between leukocytes and endothelial cells. This interaction is the initial important event in inflammation and is mediated by adhesion molecules expressed on both cell types. This interaction consists of three steps: rolling, sticking and transmigration.  Read more »

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