9 research outputs found
Colonic levels of vasoactive intestinal peptide decrease during infection and exogenous VIP protects epithelial mitochondria against the negative effects of IFNγ and TNFα induced during Citrobacter rodentium infection.
Citrobacter rodentium infection is a model for infection with attaching and effacing pathogens, such as enteropathogenic Escherichia coli. The vasoactive intestinal peptide (VIP) has emerged as an anti-inflammatory agent, documented to inhibit Th1 immune responses and successfully treat animal models of inflammation. VIP is also a mucus secretagogue. Here, we found that colonic levels of VIP decrease during murine C. rodentium infection with a similar time dependency as measurements reflecting mitochondrial function and epithelial integrity. The decrease in VIP appears mainly driven by changes in the cytokine environment, as no changes in VIP levels were detected in infected mice lacking interferon gamma (IFNγ). VIP supplementation alleviated the reduction of activity and levels of mitochondrial respiratory complexes I and IV, mitochondrial phosphorylation capacity, transmembrane potential and ATP generation caused by IFNγ, TNFα and C. rodentium infection, in an in vitro mucosal surface. Similarly, VIP treatment regimens that included the day 5-10 post infection period alleviated decreases in enzyme complexes I and IV, phosphorylation capacity, mitochondrial transmembrane potential and ATP generation as well as increased apoptosis levels during murine infection with C. rodentium. However, VIP treatment failed to alleviate colitis, although there was a tendency to decreased pathogen density in contact with the epithelium and in the spleen. Both in vivo and in vitro, NO generation increased during C. rodentium infection, which was alleviated by VIP. Thus, therapeutic VIP administration to restore the decreased levels during infection had beneficial effects on epithelial cells and their mitochondria, but not on the overall infection outcome
Epidermal growth factor receptor and proliferating cell nuclear antigen in astrocytomas
Aims: The involvement of various growth factors, growth factor
receptors and proliferative markers in the molecular pathogenesis of
astrocytic neoplasms are being studied extensively. Epidermal Growth
Factor Receptor (EGFR) gene overexpression occurs in nearly 50% of
cases of glioblastoma. Since EGFR and proliferating cell nuclear
antigen (PCNA) are involved in mitogenic signal transduction and
cellular proliferation pathway, we have studied the correlation between
the expression of EGFR and PCNA labeling index in astrocytic tumors.
Materials and Methods: We investigated the immunohistochemical
expression of EGFR and PCNA using the appropriate monoclonal antibodies
in 40 cases of astrocytic tumors of which 21 cases were glioblastoma,
eight cases were Grade III or anaplastic astrocytomas and six cases
were Grade II or diffuse astrocytomas and five cases were Grade I or
pilocytic astrocytomas. Results: Both the EGFR expression and PCNA
labeling index increase with increasing grades of astrocytomas with a
significantly high percentage of cells showing positive staining for
both EGFR and PCNA in GBM and Grade III astrocytomas compared to Grade
II astrocytomas. The expression levels of both EGFR and PCNA were low
in Grade I or pilocytic astrocytomas. Conclusions: A significant
correlation was found between EGFR overexpression and PCNA labeling
index in Grade III and Grade II astrocytomas and glioblastoma. These
suggest that the tumor proliferation, at least in higher grades of
astrocytomas is dependent in some measure on EGF and EGFR-related
signaling pathways
Reversible Bidirectional Shape Memory Effect in Polyurethanes through Molecular Flipping
Reversible bidirectional shape memory
is developed in thermoplastic
polyurethane by designing different components to enable molecular
switching from actuator domain to self-assembled rigid hard domain
and vice versa under a temperature cycle. Polycaprolactone based special
polyurethanes have been synthesized which exhibit appropriate self-assembly
behavior suitable for the shape memory effect. Reversible bidirectional
shape memory has been reported through induced strain and giving shape
at particular temperature, and the results are compared with conventional
polyurethanes which do not show any shape memory effect. The correlation
between chemical structures, self-assembly, structural evolution,
and shape memory effect has been made. Self-gripping is demonstrated
revealing the novel mechanism of molecular flipping and temperature-induced
structural change along with molecular aggregation
Reversible Bidirectional Shape Memory Effect in Polyurethanes through Molecular Flipping
Reversible bidirectional shape memory
is developed in thermoplastic
polyurethane by designing different components to enable molecular
switching from actuator domain to self-assembled rigid hard domain
and vice versa under a temperature cycle. Polycaprolactone based special
polyurethanes have been synthesized which exhibit appropriate self-assembly
behavior suitable for the shape memory effect. Reversible bidirectional
shape memory has been reported through induced strain and giving shape
at particular temperature, and the results are compared with conventional
polyurethanes which do not show any shape memory effect. The correlation
between chemical structures, self-assembly, structural evolution,
and shape memory effect has been made. Self-gripping is demonstrated
revealing the novel mechanism of molecular flipping and temperature-induced
structural change along with molecular aggregation
Reversible Bidirectional Shape Memory Effect in Polyurethanes through Molecular Flipping
Reversible bidirectional shape memory
is developed in thermoplastic
polyurethane by designing different components to enable molecular
switching from actuator domain to self-assembled rigid hard domain
and vice versa under a temperature cycle. Polycaprolactone based special
polyurethanes have been synthesized which exhibit appropriate self-assembly
behavior suitable for the shape memory effect. Reversible bidirectional
shape memory has been reported through induced strain and giving shape
at particular temperature, and the results are compared with conventional
polyurethanes which do not show any shape memory effect. The correlation
between chemical structures, self-assembly, structural evolution,
and shape memory effect has been made. Self-gripping is demonstrated
revealing the novel mechanism of molecular flipping and temperature-induced
structural change along with molecular aggregation