No abstract available

No abstract available

[en] Published in summary form only

No abstract available

No abstract available

No abstract available

No abstract available

[en] Objective: To study the significance and the effect of transcatheter arterial chemoembolization (TACE) on MMP-2 and TIMP-2 expressions. Methods: Forty-seven pathologically verified HCC patients included surgical resection alone 25 cases and second stage surgical resection after chemoembolization 22 cases. Immunohistochemical staining for MMP-2 and TIMP-2 expression were performed in all specimens. Results: There was significant difference in MMP-2 expressions between patients with or without metastasis (χ²=6.518, P<0.05) and complete capsule (χ²=6.038, P<0.05). MMP-2 expression was even lower and TIMP-2 expression was even higher in TACE group than surgical resection group (P<0.05); a significant negative correlation was observed between the expressions of MMP-2 and TIMP-2(r=-0.392, P < 0.05). Conclusion: HCC metastatic potentiality is correlative with MMP-2 and TIMP-2 expressions and chemoembolization is helpful for restraining the invasive and metastatic potentialities of HCC. (authors)

[en] The photochemistry of phenacyl, 1-, and 2-napthacyl α-chymotrypsins has been studied using light of wavelengths greater than 310 nm. Irradiation of these modified enzymes, having aracyl chromophores covalently bound at Met-192, led to partial regeneration of their esterase activity. The initial rates of photoreactivation have been found to be dependent on the hydrogen ion concentration and on the presence of potential competitive inhibitors having triplet energies lower than the chromophores initially receiving the light energy. Irradiation of carbonyl-¹⁴C-labeled phenacyl α-chymotrypsin resulted in partial loss of this radiolabeled from the protein at a rate concurrent with the increase in esterase activity. These results have been interpreted and discussed in terms of a dual photochemical behavior of these modified enzymes involving (1) cleavage of the Met-192 sulfur--phenacyl α-carbon bond leading to liberation of α-chymotrypsin and substituted phenone(s) and (2) photoaffinity labeling of one or more of the functional groups in the enzyme active-site region

[en] The structure of porcine pepsin crystallized in the presence of dimethyl sulphoxide has been analysed by X-ray crystallography to obtain insights into the structural events that occur at the onset of chemical denaturation of proteins. The results show that one dimethyl sulphoxide molecule occupies a site on the surface of pepsin interacting with two of its residues. An increase in the average temperature factor of pepsin in the presence of dimethyl sulphoxide has been observed indicating protein destabilization induced by the denaturant. Significant increase in the temperature factor and weakening of the electron density have been observed for the catalytic water molecule located between the active aspartates. The conformation of pepsin remains unchanged in the crystal structure. However, the enzyme assay and circular dichroism studies indicate that dimethyl sulphoxide causes a slight change in the secondary structure and complete loss of activity of pepsin in solution