Citations

Purpose To determine the maximum tolerated dose, toxicity, and pharmacokinetics of gemcitabine in children with refractory solid tumors. Patients and Methods Gemcitabine was given as a 30-minute infusion for 2 or 3 consecutive weeks every 4 weeks, to 42 patients aged 1 to 21 years. Doses of 1,000, 1,200 and 1,500 mg/m2 were administered for 3 weeks. Subsequently, gemcitabine was given for only 2 consecutive weeks at 1,500, 1,800, and 2,100 mg/m2. Plasma concentrations of gemcitabine and its metabolite, 2′2′-difluorodeoxyuridine, were measured in 28 patients. Results Forty patients who received 132 courses of gemcitabine were assessable for toxicity. The maximum tolerated dose of gemcitabine given weekly for 3 weeks was 1,200 mg/m2. Dose-limiting toxicity was not seen in one-third of children treated at any doses given for 2 weeks. The major toxicity was myelosuppression in three of five patients at 1,500 mg/m2 for 3 weeks, and one of seven patients at 1,800 mg/m2 for 2 weeks. Other serious adverse events were somnolence, fever and hypotension, and rash in three patients. Gemcitabine plasma concentration–time data were fit to a one- (n = 5) or two-compartment (n = 23) open model. Mean gemcitabine clearance and half-life values were 2,140 mL/min/m2 and 13.7 minutes, respectively. One patient with pancreatic cancer had a partial response. Seven patients had stable disease for 2 to 17 months. Conclusion Gemcitabine given by 30-minute infusion for 2 or 3 consecutive weeks every 4 weeks was tolerated well by children at doses of 2,100 mg/m2 and 1,200 mg/m2, respectively.

Abstract In an effort to facilitate the use of interference screw fixation in the tibia, a method to orient the tibial tunnel termed the “N + 7 Rule” was prospectively applied to 60 consecutive endoscopic anterior cruciate ligament reconstructions performed by a single surgeon. Four cases were excluded because a breach in the described protocol for application of the N + 7 rule was identified at the time of the operation. Of the remaining 56 cases, 28 (50%) were fixed with an interference screw on the tibia, whereas 28 (50%) required fixation with sutures tied over a post. The 28 cases not amenable to interference screw fixation included 17 cases in which the tibial tunel was too long and 11 cases in which the tunnnel was too short. It appears that the applicability of the N + 7 rule to an individual surgeon's practice may be altered by small variations in operative technique.

There has been increasing recognition of the detrimental impact of peripheral arterial disease (PAD) on the health of Americans, and yet there is no common national program of public PAD education designed to diminish this impact. To heighten awareness of this problem, a 2-day PAD Public Education Strategy Meeting was recently attended by representatives of 17 professional societies and public health associations whose missions support the prevention, diagnosis, treatment, and rehabilitation of vascular diseases. This Public Education Strategy Meeting was intended to provide the rationale and structure to create a national PAD public awareness campaign to diminish the health impact of PAD, and to improve cardiovascular outcomes in the USA. This paper: (1) provides the rationale for creation of a national PAD public education program; (2) reviews the development and success of national hypertension, hypercholesterolemia, and Women’s Heart Health public education programs as models of educational efficacy; (3) elucidates how the work of many vascular professionals has led to a national consensus for creation of a national PAD public educational program; (4) provides an overview of the National Heart, Lung and Blood Institute PAD education meeting; and (5) outlines the ‘next steps’ required to accomplish these goals. This meeting achieved consensus that we share responsibility for developing accurate, unified messages to promote PAD awareness and improved care. Participants agreed that the creation of such messages should be linked to plans to disseminate them to all Americans at risk. A consensus was reached that such messages, when commonly created and offered to the public, are most likely to achieve the rewards in better health that all Americans deserve. The Vascular Disease Foundation, a not-for-profit foundation whose mission includes public education regarding the prevention, diagnosis, treatment, and rehabilitation of PAD, will devote its resources to guide a new coalition in this process and to create a national PAD awareness campaign. During 2003 and 2004, the coalition will create the organizational underpinnings and timeline for what will undoubtedly be a multi-year effort. In conclusion, participants of the Public Education Strategy Meeting agreed to create a broad coalition to develop a national PAD public awareness program, with the objectives to develop and disseminate public education messages on PAD. A successful national PAD education program will contribute to the creation of a broader mandate to improve global cardiovascular health in the USA.

Dynamins are a family of 100-kD GTPases comprised of at least three distinct gene products and multiple alternatively spliced variants. Homologies with the shibire gene product in Drosophila melanogaster and with Vps1p and Dnm1p in Saccharomyces cerevisiae suggest that dynamins play an important role in vesicular transport. Morphological studies have localized brain dynamin to coated pits and tubular invaginations at the plasma membrane, where it is believed to facilitate the formation of endocytic vesicles. Because similar membrane-budding events occur at the Golgi apparatus and multiple dynamin isoforms exist, we have studied the distribution of dynamins in mammalian cells. To this end, we generated and characterized peptide-specific antibodies directed against conserved regions of the dynamin family. By immunoblot analysis, these antibodies reacted specifically with a 100-kD protein in fibroblasts that sedimented with membranes and microtubules in vitro in a manner similar to brain dynamin. By immunofluorescence microscopy, these antibodies strongly labeled the Golgi complex in cultured fibroblasts and melanocytes, as confirmed by double labeling with a Golgi-specific antibody. Furthermore, Western blot analysis showed significant enrichment of a 100-kD dynamin band in Golgi fractions isolated from the liver. To substantiate these findings, we use a specific antidynamin antibody to immunoisolate Golgi membranes from subcellular Golgi fractions, as determined by EM and immunoblot analysis. This study provides the first morphological and biochemical evidence that a dynamin-like protein associates with the Golgi apparatus in mammalian cells, and suggests that dynamin-related proteins may have multiple cytoplasmic distributions. The potential contributions of dynamin to the secretory and endocytic pathways are discussed.

Abstract Imatinib mesylate (STI571, imatinib) inhibited DNA synthesis in primary human T cells stimulated with allogeneic mature dendritic cells or phytohemagglutinin (PHA) but did not induce apoptosis. The values for the concentration that inhibits 50% (IC50) of T-cell proliferation stimulated by dendritic cells and PHA were 3.9 μM and 2.9 μM, respectively, that is, within the concentration range found in patients treated with imatinib mesylate. Interestingly, imatinib mesylate did not inhibit expression of T-cell activation markers CD25 and CD69, although it reduced the levels of activated nuclear factor-κB (NF-κB) and changed phosphorylation or protein levels of Lck, ERK1/2, retinoblastoma protein, and cyclin D3. When T cells were washed free of imatinib mesylate, they proliferated in response to PHA, demonstrating that inhibition is reversible. Treatment with imatinib mesylate led to accumulation of the cells in G0/G1 phase of the cell cycle. The in vitro observations were confirmed in vivo in a murine model of delayed-type hypersensitivity (DTH). In mice treated with imatinib mesylate, DTH was reduced in comparison to sham-injected controls. However, the number of splenic T cells was not reduced showing that, similarly to in vitro observations, imatinib mesylate inhibited T-cell response, but did not cause apoptosis. These findings indicate that long-term administration of high-dose imatinib mesylate might affect immunity.

Epithelial cells in vivo form tight cell-cell associations that spatially separate distinct apical and basolateral domains. These domains provide discrete cellular processes essential for proper tissue and organ development. Using confocal imaging and selective plasma membrane domain activation, the type I and type II transforming growth factor-β (TGFβ) receptors were found to be localized specifically at the basolateral surfaces of polarized Madin-Darby canine kidney (MDCK) cells. Receptors concentrated predominantly at the lateral sites of cell-cell contact, adjacent to the gap junctional complex. Cytoplasmic domain truncations for each receptor resulted in the loss of specific lateral domain targeting and dispersion to both the apical and basal domains. Whereas receptors concentrate basolaterally in regions of direct cell-cell contact in nonpolarized MDCK cell monolayers, receptor staining was absent from areas of noncell contact. In contrast to the defined basolateral polarity observed for the TGFβ receptor complex, TGFβ ligand secretion was found to be from the apical surfaces. Confocal imaging of MDCK cells with an antibody to TGFβ1 confirmed a predominant apical localization, with a stark absence at the basal membrane. These findings indicate that cell adhesion regulates the localization of TGFβ receptors in polarized epithelial cultures and that the response to TGFβ is dependent upon the spatial distribution and secretion of TGFβ receptors and ligand, respectively.

AbstractPrimary systemic amyloidosis (AL) is a fatal plasma cell disorder. Pilot data suggest survival is better in patients undergoing peripheral blood stem cell transplantation (PBSCT), but the selection process makes the apparent benefit suspect. We have reported that circulating cardiac biomarkers are the best predictors of survival outside of the transplantation setting. We now test whether cardiac troponins (cTnT and cTnI) and N-terminal pro-brain natriuretic peptide (NT-proBNP) are prognostic in transplant recipients. In 98 patients with AL undergoing PBSCT, serum cardiac biomarkers were measured (cTnT, 98 patients; cTnI, 65 patients; and NT-proBNP, 63 patients). Elevated levels of cTnT, cTnI, and NT-proBNP were present in 14%, 43%, and 48% of patients, respectively. At 20 months median follow-up, median survival has not been reached for patients with values below the thresholds; in patients with values above the thresholds, median survival is 26.1 months, 66.1 months, and 66.1 months, respectively. Our previously reported risk systems incorporating these markers were also prognostic, notably the cTnT/NT-proBNP staging. Using this system, 49%, 38%, and 13% of patients were in stage I, stage II, and stage III, respectively. Determining levels of circulating biomarkers may be the most powerful tool for staging patients with AL undergoing PBSCT.