Primary vs. delayed resection for obstructive left-sided colorectal cancer: impact of surgery on patient outcome.

PURPOSE: By comparing surgical outcomes between primary and delayed resection, we addressed whether and how surgical strategies impacted prognosis of patients with left-sided colorectal cancer underwent emergency curative resection. METHODS: Between January 1980 and December 2002, a total of 143 patients were identified who presented with obstructive left-sided colorectal cancer and received emergency curative resection in Taipei Veterans General Hospital. Patients were stratified according to the timing of tumor resection into two groups: primary resection and delayed resection. Demographic data of the patients, characteristics of the tumors, and short-term and long-term outcomes were analyzed and compared between the two groups. RESULTS: The demographic data and tumor characteristics did not differ between the two groups except for more rectal cancers in the delayed resection group (P=0.021). Primary resection group had a higher anastomotic leakage rate (P=0.017) and a trend toward a higher mortality rate, which did not reach statistical significance (P=0.063). The median follow-up intervals were similar (60.4 vs. 58.3 months; P=0.79). The median survival tended to be longer in delayed resection group (66 vs. 105 months; P=0.088). Overall five-year and ten-year survival for primary resection were 43.7 and 31.9 percent, respectively, compared with 67.2 and 53.2 percent, respectively, for delayed resection. CONCLUSIONS: Delayed resection seems to be a safer procedure and provided a better oncologic outcome compared with primary resection in obstructive left-sided colorectal cancer under emergency situations.

Roles of the three major phosphorylation sites of hepatitis B virus core protein in viral replication.

Hepatitis B virus (HBV) core protein is a phosphoprotein. Its three major phosphorylation sites have been identified at the serine residues located at amino acids 157, 164, and 172. In order to investigate the role of core protein phosphorylation in HBV replication, these three serine residues were mutated to alanine to mimic nonphosphorylated serine or to glutamic acid to mimic phosphoserine. The nonphosphorylated core protein analog did not package the HBV pregenomic RNA, and the phosphorylated analog packaged the pregenomic RNA but failed to support viral DNA replication. These results indicate that the core protein phosphorylation may be important for pregenomic RNA packaging and that its dephosphorylation may be important for viral DNA replication. The individual roles of these three major phosphorylation sites in HBV replication were further investigated by being mutated to alanine in different combinations. The results showed that the serine residue at amino acid 157 was not essential for pregenomic RNA packaging, whereas the serine residues at amino acids 164 and 172 were more important. Furthermore, the serine residue at amino acid 157 was not essential for viral DNA replication or viral maturation.

Evidence that the B2 chain of laminin is responsible for the neurite outgrowth-promoting activity of astrocyte extracellular matrix.

Extracellular matrix (ECM) derived from cerebral cortical astrocytes stimulates neurite outgrowth from pheochromocytoma (PC12) cells in the absence of the classical nerve growth factor (NGF). We have shown here that astrocyte ECM can also stimulate neurite outgrowth from primary cultures of central nervous system (CNS) neurons. Using PC12 cells for a quantitative assay, we also demonstrated that the neurite growth-promoting activity increased as the astrocytes matured in vitro: ECM from older astrocytes (3-12 weeks in vitro) exhibited two-fold more neurite growth-promoting activity than ECM for younger astrocytes (5 days to 2 weeks in vitro). We applied various antibodies to identify the neurite growth-promoting factor of astrocyte ECM and found that anti-laminin inhibited neurite outgrowth by 50%, whereas anti-fibronectin and anti-NGF had no effect. Immunoblots, using laminin chain-specific antibodies, and cDNA hybridization of laminin mRNA demonstrated that cultured astrocytes synthesize only the B2 chain of laminin. This suggests that the B2 chain of laminin suffices to stimulate neurite outgrowth.