Citations

Purpose Fluorouracil (FU)-leucovorin (LV), irinotecan, and oxaliplatin administered alone or in combination have proven effective in the treatment of advanced colorectal cancer (CRC). Combination protocols using FU-LV with either irinotecan or oxaliplatin are currently regarded as standard first-line therapies in this disease. However, the importance of the availability of all three active cytotoxic agents, FU-LV, irinotecan, and oxaliplatin, on overall survival (OS) has not yet been evaluated. Materials and Methods We analyzed data from seven recently published phase III trials in advanced CRC to correlate the percentage of patients receiving second-line therapy and the percentage of patients receiving all three agents with the reported median OS, using a weighted analysis. Results The reported median OS is significantly correlated with the percentage of patients who received all three drugs in the course of their disease (P = .0008) but not with the percentage of patients who received any second-line therapy (P = .19). In addition, the use of combination protocols as first-line therapy was associated with a significant improvement in median survival of 3.5 months (95% CI, 1.27 to 5.73 months; P = .0083). Conclusion Our results support the strategy of making these three active drugs available to all patients with advanced CRC who are candidates for such therapy to maximize OS. In addition, our findings suggest that, with the availability of effective salvage options, OS should no longer be regarded as the most appropriate end point by which to assess the efficacy of a palliative first-line treatment in CRC.

Background Previous studies suggest that intraoperative anesthetic care may influence postoperative pain and recovery from surgery. The authors tested the hypothesis that the addition of intrathecal analgesia to general anesthesia would improve long-term functional status and decrease pain in patients undergoing radical retropubic prostatectomy. Methods One hundred patients received either general anesthesia supplemented with intravenous fentanyl or general anesthesia preceded by intrathecal administration of bupivacaine (15 mg), clonidine (75 microg), and morphine (0.2 mg). Patients and providers were masked to treatment assignment. All patients received multimodal pain management postoperatively. Primary outcomes included pain and functional status over the first 12 postoperative weeks. Results Patients receiving intrathecal analgesia required more intravenous fluids and vasopressors intraoperatively. Pain was well controlled throughout the study (mean numerical pain scores < 3 in both groups at all times studied). Intrathecal analgesia decreased pain and supplemental intravenous morphine use over the first postoperative day but increased the frequency of pruritus. Pain and functional status after discharge from the hospital did not differ between groups. Intrathecal analgesia significantly decreased the duration of hospital stay (from 2.8 +/- 2.0 to 2.1 +/- 0.5 days; P < 0.01) as a result of five patients in the control group who stayed in the hospital more than 3 days. Conclusions The benefits of improved immediate analgesia and decreased morphine requirements resulting from intrathecal analgesia must be weighed against factors such as pruritus, increased intraoperative requirement for fluids and vasopressors, and resources needed to implement this modality. Further studies are needed to determine the significance of the decrease in duration of hospital stay.

GPI-PLD [glycosylphosphatidylinositol (GPI)-specific phospholipase D (PLD)] is a secreted mammalian enzyme that specifically cleaves GPI-anchored proteins. In addition, the enzyme has been shown to cleave GPI anchor intermediates in cell lysates. The biosynthesis of the GPI anchor is well characterized; however, the mechanisms by which the levels of GPI anchor intermediates are regulated are still unknown. To investigate whether GPI-PLD plays a role in this regulation, we isolated stable HeLa cells overexpressing the enzyme. GPI-PLD-HeLa (GPI-PLD-transfected HeLa) cells showed a 3-fold increase in intracellular GPI-PLD activity and drastically decreased the levels of GPI-anchored proteins when compared with untransfected HeLa controls. Intracellular cleavage of GPI-anchored proteins has been suggested to occur early in the secretory pathway and, in agreement with this proposal, GPI-PLD activity in GPI-PLD-HeLa cells was detected not only in the endoplasmic reticulum and Golgi apparatus, but also in the plasma membrane. The enzyme was also active in lipid rafts, membrane microdomains in which GPI-anchored proteins and GPI anchor intermediates are concentrated, indicating that intracellular GPI-PLD cleavage may also occur in this compartment. Pulse–chase paradigms revealed the turnover rate of the last intermediate of the GPI anchor pathway in GPI-PLD-HeLa cells to be accelerated compared with the controls. Furthermore, 1,10-phenanthroline, a GPI-PLD inhibitor, reversed this effect. Our studies demonstrated that GPI-PLD can cleave not only GPI-anchored proteins, but also GPI anchor intermediates intracellularly. This observation opens the possibility that GPI-PLD can influence the steady-state levels of GPI-anchored proteins by hydrolysing the anchor before and after its attachment to proteins.

Although all three Vav family members are expressed in T lymphocytes, the role that Vav3 plays in T cell activation is poorly defined. Here we show that, like Vav1, Vav3 undergoes rapid tyrosine phosphorylation after T cell receptor (TCR) cross-linkage and interacts with the adaptor molecules SLP76 and 3BP2 in a SH2-dependent manner. However, depletion of Vav1 but not Vav3 protein by RNA interference affects TCR-mediated IL-2 promoter activity. In contrast, Vav3 function is specifically required for coupling TCR stimulation to serum response element–mediated gene transcription. These data indicate that, although both Vav proteins are biochemically coupled to the TCR, they regulate distinct molecular pathways leading to defined gene transcriptional events.

Fluorodeoxyglucose positron emission tomography (PET) studies have found that patients with Alzheimer's dementia (AD) have abnormally low rates of cerebral glucose metabolism in posterior cingulate, parietal, temporal, and prefrontal cortex. We previously found that cognitively normal, late-middle-aged carriers of the apolipoprotein E ε4 allele, a common susceptibility gene for late-onset Alzheimer's dementia, have abnormally low rates of glucose metabolism in the same brain regions as patients with probable AD. We now consider whether ε4 carriers have these regional brain abnormalities as relatively young adults. Apolipoprotein E genotypes were established in normal volunteers 20–39 years of age. Clinical ratings, neuropsychological tests, magnetic resonance imaging, and PET were performed in 12 ε4 heterozygotes, all with the ε3/ε4 genotype, and 15 noncarriers of the ε4 allele, 12 of whom were individually matched for sex, age, and educational level. An automated algorithm was used to generate an aggregate surface-projection map that compared regional PET measurements in the two groups. The young adult ε4 carriers and noncarriers did not differ significantly in their sex, age, educational level, clinical ratings, or neuropsychological test scores. Like previously studied patients with probable AD and late-middle-aged ε4 carriers, the young ε4 carriers had abnormally low rates of glucose metabolism bilaterally in the posterior cingulate, parietal, temporal, and prefrontal cortex. Carriers of a common Alzheimer's susceptibility gene have functional brain abnormalities in young adulthood, several decades before the possible onset of dementia.

Protein kinase C (PKC) phosphorylation stimulates the cystic fibrosis transmembrane conductance regulator (CFTR) channel and enhances its activation by protein kinase A (PKA) through mechanisms that remain poorly understood. We have examined the effects of mutating consensus sequences for PKC phosphorylation and report here evidence for both stimulatory and inhibitory sites. Sequences were mutated in subsets and the mutants characterized by patch clamping. Activation of a 4CA mutant (S707A/S790A/T791A/S809A) by PKA was similar to that of wild-type CFTR and was enhanced by PKC, whereas responses of 3CA (T582A/T604A/S641A) and 2CA (T682A/S686A) channels to PKA were both drastically reduced (>90%). When each mutation in the 3CA and 2CA constructs was studied individually in a wild-type background, T582, T604, and S686 were found to be essential for PKA activation. Responses were restored when these three residues were reintroduced simultaneously into a 9CA mutant lacking all nine PKC consensus sequences (R6CA revertant); however, PKC phosphorylation was not required for this rescue. Nevertheless, two of the sites (T604 and S686) were phosphorylated in vitro , and PKC alone partially activated wild-type CFTR, the 4CA mutant, and the point mutants T582A and T604A, but not S686A channels, indicating that PKC does act at S686. The region encompassing S641 and T682 is inhibitory, because S641A enhanced activation by PKA, and T682A channels had 4-fold larger responses to PKC compared to wild-type channels. These results identify functionally important PKC consensus sequences on CFTR and will facilitate studies of its convergent regulation by PKC and PKA.

Purpose Three agents with differing mechanisms of action are available for treatment of advanced colorectal cancer: fluorouracil, irinotecan, and oxaliplatin. In this study, we compared the activity and toxicity of three different two-drug combinations in patients with metastatic colorectal cancer who had not been treated previously for advanced disease. Patients and Methods Patients were concurrently randomly assigned to receive irinotecan and bolus fluorouracil plus leucovorin (IFL, control combination), oxaliplatin and infused fluorouracil plus leucovorin (FOLFOX), or irinotecan and oxaliplatin (IROX). The primary end point was time to progression, with secondary end points of response rate, survival time, and toxicity. Results A total of 795 patients were randomly assigned between May 1999 and April 2001. A median time to progression of 8.7 months, response rate of 45%, and median survival time of 19.5 months were observed for FOLFOX. These results were significantly superior to those observed for IFL for all end points (6.9 months, 31%, and 15.0 months, respectively) or for IROX (6.5 months, 35%, and 17.4 months, respectively) for time to progression and response. The FOLFOX regimen had significantly lower rates of severe nausea, vomiting, diarrhea, febrile neutropenia, and dehydration. Sensory neuropathy and neutropenia were more common with the regimens containing oxaliplatin. Conclusion The FOLFOX regimen of oxaliplatin and infused fluorouracil plus leucovorin was active and comparatively safe. It should be considered as a standard therapy for patients with advanced colorectal cancer.