Chalcone (CHS) and stilbene (STS) synthases are related plant-specific polyketide synthases that are key enzymes in the biosynthesis of flavonoids and of stilbene phytoalexins, respectively. A phylogenetic tree constructed from 34 CHS and four STS sequences revealed that the STS formed no separate cluster but grouped with CHS from the same or related plants. This suggested that STS evolved from CHS several times independently. We attempted to stimulate this by site-directed mutagenesis of an interfamily CHS/STS hybrid, which contained 107 amino acids of a CHS from Sinapis alba (N-terminal) and 287 amino acids of a STS from Arachis hypogaea. The hybrid had no enzyme activity. Three amino acid exchanges in the CHS part (Gln-100 to Glu, Val-103 to Met, Val-105 to Arg) were sufficient to obtain low STS activity, and one additional exchange (Gly-23 to Thr) resulted in 20-25% of the parent STS activity. A kinetic analysis indicated (1) that the hybrids had the same Km for the substrate 4-coumaroyl-CoA but a lower Vmax than the parent STS, and (2) that they had a different substrate preference than the parent STS and CHS. Most of the other mutations and their combinations led to enzymatically inactive protein aggregates, suggesting that the subunit folding and/or the dimerization was disturbed. We propose that STS evolved from CHS by a limited number of amino acid exchanges, and that the advantage gained by this enzyme function favored the selection of plants with improved STS activity.

This is the first case of consecutive patients undergoing ambulatory colectomy for malignant or benign disease. We demonstrated the feasibility, safety, and reproducibility of outpatient colectomy for selected patients. In our experience, 30% of patients scheduled for elective colectomy can be managed in an ambulatory setting.

No abstract

During inflammatory processes of the kidney, lesions of the glomerulus lead to aggregation of thrombocytes and infiltration of macrophages, which can release bioactive mediators. One of these important signalling molecules is lysophosphatidic acid (LPA). Incubation of rat mesangial cells with LPA induced mRNA and protein expression of the early-response genes pghs-2 (for prostaglandin G/H synthase-2/cyclo-oxygenase-2) and egr-1. As shown by antisense experiments, induction of egr-1 was related to the strong mitogenic effect of LPA. LPA-mediated gene expression was inhibited by pertussis toxin, indicating coupling to G-proteins of the Gi family. Specific inhibition of proteins of the small G-protein subfamily Rho with toxin B from Clostridium difficile led to changes in mesangial cell morphology without induction of apoptosis. LPA-mediated expression of pghs-2 and egr-1 was reduced to base-line levels by toxin B, indicating a role for Rho proteins in LPA-mediated gene induction. Of the two mitogen-activated protein kinase (MAPK) pathways investigated, the MAPK kinase-extracellular signal-regulated kinase pathway was involved in the induction of both pghs-2 and egr-1 mRNA expression, as shown by the inhibitory effect of PD98059. Activation of the MAPK p38, however, was only related to pghs-2 expression, whereas egr-1 expression was not affected by treatment of mesangial cells with the specific inhibitor SB203580. Taken together our data provide evidence that LPA-mediated activation of MAPK kinase and Rho proteins leads to the induction of the functionally distinct early-response genes pghs-2 and egr-1, whereas activation of MAPK p38 revealed considerable differences between the regulation of these two genes.

Introduction: The application of a fast-track recovery program after surgery can decrease the physiological impact of surgery and reduce the duration of hospitalisation compared to conventional care. This program has permitted us to consider the performance of colectomy on an outpatient basis. Method: After analyzing the recommendations for fast-track recovery, we developed and validated a specific protocol. Drawing on extensive experience in ambulatory surgery (inguinal hernia, cholecystectomy, adjustable gastric-banding), we formalized a protocol for outpatient colectomy. Patient selection criteria were the absence of serious or decompensated comorbidity, very good general condition, and full patient understanding of the procedure. Discharge was authorized if the patient met the exit criteria according to the Chung score. Postoperative surveillance was provided by regular home visits of a nurse trained in enhanced recovery, every afternoon until day 10. Results: Five patients underwent this management strategy (4 men and 1 woman, mean age 64 years, range: 59-69), for indications including cancer of the rectosigmoid junction (1 case), sigmoid diverticulitis (3 cases), and volvulus. The postoperative course was simple and uncomplicated except for two patients who had dysuria and an incisional hematoma, respectively. Conclusion: To our knowledge, these are the first cases of colectomy performed strictly on an outpatient basis (i.e., stay < 12 h). We demonstrated the feasibility of outpatient colectomy when integrated into a protocol of enhanced recovery for selected patients provided that athome monitoring was available.