Outcomes in a series of 103 retroperitoneal sarcomas.

AIMS: To report the effect on outcome of selection in patients receiving intra-operative electron beam radiation (IOERT) and external beam radiation therapy (EBRT). METHODS: One hundred and three patients treated for primary RS were studied. Median follow-up was 27 months. Clinical presentation, tumor characteristics, and treatment methods were analyzed to determine impact on survival and recurrence and if selection was occurring. RESULTS: Mean age was 55+/-17 years. Mean tumor size was 15+/-6cm and 88 were high-grade. Complete gross tumor resection (CR) occurred in 62 patients and improved survival vs. both debulking (p=0.0005) and biopsy (p<0.0001). The 5- and 10-year survival rates were 62% and 52% for those with CR vs. 29% and 20% after incomplete resection. Among the 62 CR patients, there was selection to receive additional EBRT+/-IOERT in patients with high-grade tumors (p=0.005) and/or microscopically positive margins (p=0.011). In these high-risk patients there was a trend for IOERT to further augment survival vs. EBRT alone and to increase the time to both local and distant recurrences (p=0.036). CONCLUSIONS: Complete gross resection is the primary form of curative treatment for retroperitoneal sarcomas. Selection led to patients with high-risk tumors receiving additional radiation therapy. There appears to be a beneficial effect of IOERT plus EBRT in these high-risk patients after complete tumor resection.

Mechanisms governing the expression of the enzymes of glutamine metabolism--glutaminase and glutamine synthetase.

Whether on the scale of a single cell, organ or organism, glutamine homeostasis is to a large extent determined by the activities of glutaminase (GA, EC 3.5.1.2) and glutamine synthetase (GS, EC 6.3.1.2), the two enzymes that are the focus of this report. GA and GS each provide examples of regulation of gene expression at many different levels. In the case of GA, two different genes (hepatic- and kidney-type GA) encode isoforms of this enzyme. The expression of hepatic GA mRNA is increased during starvation, diabetes and high protein diet through a mechanism involving increased gene transcription. In contrast, the expression of kidney GA mRNA is increased post-transcriptionally by a mechanism that increases mRNA stability during acidosis. We found recently that several isoforms of rat and human kidney-type GA are formed by tissue-specific alternative RNA splicing. Although the implications of this post-transcriptional processing mechanism for GA activity are not yet clear, it allows for the expression of different GA isoforms in different tissues and may limit the expression of GA activity in muscle tissues by diverting primary RNA transcripts to a spliceform that produces a nonfunctional translation product. The expression of GS enzyme is also regulated by both transcriptional and post-transcriptional mechanisms. For example, the GS gene is transcriptionally activated by glucocorticoid hormones in a tissue-specific fashion. This hormonal response allows GS mRNA levels to increase in selected organs during catabolic states. However, the ultimate level of GS enzyme expression is further governed by a post-transcriptional mechanism regulating GS protein stability. In a unique form of product feedback, GS protein turnover is increased by glutamine. This mechanism appears to provide a means to index the production of glutamine to its intracellular concentration and, therefore, to its systemic demand. Herein, we also provide experimental evidence that GS protein turnover is dependent upon the activity of the 26S proteosome.

Glutamine metabolism in sepsis and infection.

Severe infection causes marked derangements in the flow of glutamine among organs, and these changes are accompanied by significant alterations in regional cell membrane transport and intracellular glutamine metabolism. Skeletal muscle, the major repository of glutamine, exhibits a twofold increase in glutamine release during infection, which is associated with a significant increase in endogenous glutamine biosynthesis. Despite an increase in glutamine synthetase activity in skeletal muscle, the intracellular glutamine pool becomes depleted, indicating that release rates exceed rates of synthesis. Simultaneously, the circulating pool of glutamine does not increase, indicating accelerated uptake by other organs. The liver appears to be the major organ of glutamine uptake in severe infection; studies in endotoxemic rodents have shown net hepatic glutamine uptake to increase by as much as 8- to 10-fold. This increase is due partially to increases in liver blood flow, but also to a three- to fourfold increase in hepatocyte System N activity in the liver. Cytokines and glucocorticoids mediate the increased uptake of glutamine by the liver in septic states as well as other compounds. Sepsis does not appear to induce an increase in System N gene expression, indicating that the increase in hepatic glutamine transport observed during severe infection is probably regulated at the protein level. The bowel displays a decrease in glutamine utilization during sepsis, a response that may be related to the decrease in circulating insulin-like growth factor-1 (IGF-1) levels that is characteristic of sepsis. Recent studies suggest that IGF-1 has a direct effect on stimulating glutamine transport across the gut lumen and thus may represent a therapeutic avenue for improving gut nutrition during severe infection. The cells of the immune system (lymphocytes, macrophages) are also major glutamine consumers during inflammatory states in which cell proliferation is increased. Under these conditions, glutamine availability can become rate limiting for key cell functions, such as phagocytosis and antibody production.

The effect of surgical site infections on outcomes and resource utilization after liver transplantation.

BACKGROUND: Although postoperative infections have a significant impact on morbidity and mortality after orthotopic liver transplantation (OLT), less is known about their economic implications. In this study, we sought to identify risk factors and estimate the impact of surgical site infections on 1-year mortality, graft survival, and resource utilization after OLT. METHODS: We studied 777 first, single-organ liver transplant recipients from the National Institute of Diabetes and Digestive and Kidney Diseases Liver Transplantation Database. Surgical site infections (n = 292, 37.8%) were defined as bacterial or fungal infections of the liver, intestine, biliary tract, surgical wound, or peritoneum within 1 year of transplantation. A subset of these (n = 159) occurred during the transplant hospitalization and were used to estimate excess charges associated with surgical site infections. RESULTS: Leaks in the choledochojejunostomy (odds ratio [OR] = 7.1, P =.001) and choledochocholedochostomy (OR = 2.5, P =.002), extended operation duration in hours (OR = 1.2, P =.002), serum albumin levels in grams per liters (OR = 0.71, P =.009), ascites (OR = 1.43, P =.037), and administration of OKT3 within 7 days (OR = 1.49, P =.039) significantly increased risk of infection. Surgical site infections did not significantly increase 1-year mortality (88.5% vs 91.5%, P =.19) but significantly increased 1-year graft loss (79.8% vs 86.5%, P =.022). Patients with surgical site infections incurred approximately 24 extra hospital days and $159,967 in excess charges (P =.0001). Multivariate analysis reduced the estimate of excess charges to $131,276 (P =.0001). CONCLUSIONS: Liver transplant recipients who develop surgical site infection have significantly higher resource utilization requirements than those who do not. These results imply substantial returns to preventative efforts directed at surgical site infections in patients undergoing OLT.

Political strategy, business strategy, and the academic medical center: linking theory and practice.

The purpose of this paper is to link external political strategy theory to a specific health care setting-that of the academic medical center (AMC). Political strategy encompasses those activities undertaken by AMCs to acquire, develop, and use power (clout, influence, and credibility) to gain an advantage in situations of conflict. It should be differentiated from internal politics, a topic that will not be dealt with in this review. Political strategy should also be distinguished from but not divorced from competitive strategy. As political and social action can change the competitive landscape and the rules of competition, AMCs must become adept in issues management and stakeholder management. The focus on political strategy is a reflection of the enormous changes in the external environment that have impacted AMCs in recent years. These changes have often emerged out of political and social action and they impact significantly on the organization's more traditional business strategies. We suggest that a tighter alignment between political and business strategies in the future will help ensure organizational survival and success. This article reviews the literature and theory in corporate political strategy and illustrates the application of political strategy with examples of issues and problems faced by AMCs. Models of political strategy are well crafted, and this article concludes with succinct observations on the use of political strategies to enhance the business-based strategies of AMCs. Although the focus is on AMCs, the use of political strategies is applicable to any health care institution.

Asparagine uptake in rat hepatocytes: resolution of a paradox and insights into substrate-dependent transporter regulation.

Extracellular asparagine has previously been shown to markedly stimulate both ornithine decarboxylase and System N-mediated glutamine transport activities in hepatocytes by a transport-dependent mechanism. However, as a weak substrate of its inferred transporter System N, the specific route of asparagine uptake has remained enigmatic. In this study, asparagine transport was studied in detail and shown to be Na+-dependent, Li+-tolerant, stereospecific, and inhibited profoundly by glutamine and histidine. Coupled with competitive inhibition by glutamine (Ki = 2.63+/-1.11 mM), the data indicated that asparagine was indeed slowly transported by System N in rat hepatocytes, albeit at rates an order of magnitude less than for glutamine. The differential substrate transport velocities were shown to be attributable to a low transporter asparagine affinity (Km = 9.3 - 17.5mM) compared to glutamine (Km approximately 1 mM). Consistent with its slow uptake, asparagine accumulated to a fivefold lesser degree than glutamine after 60 min, yet stimulated System N activity to the same extent as glutamine. The transaminase inhibitor aminooxyacetate and starvation of the donor animal each enhanced asparagine uptake twofold and augmented subsequent transporter activation. Conversely, asparagine-dependent System N stimulation was abrogated by hyperosmotic media and blunted 30%-40% by phosphatidylinositol 3-kinase (PI3K) inhibitors wortmannin and LY294002. Collectively, the data suggest that System N-mediated asparagine uptake serves an autostimulatory role, mediated by cellular swelling and in part by a PI3K-dependent signal transduction pathway.

Marketing strategy: an essential component of business development for academic health centers.

BACKGROUND: Historically, academic health centers (AHCs) have detached themselves from commercialism and entrepreneurism, viewing these activities as being inconsistent with many of their core academic values. Word-of-mouth promotion was their primary, if not sole, marketing strategy. Less emphasis was placed on preparing, pricing, distributing, and promoting these services to targeted audiences. Understanding customers' needs was not a top priority. METHODS: The marketing strategies and tools currently being developed and utilized by AHCs were reviewed. RESULTS: In an effort to attract customers and win contracts, AHCs are aggressively marketing themselves by designing new services, promoting those services much more intensely, restructuring the entire distribution system that delivers those services, and crafting pricing strategies that build in flexibility. With growing frequency, these marketing tactics are part and parcel of a carefully crafted data-driven strategic plan designed to meet the business-development goals of the institution. CONCLUSIONS: In order to carry out their missions, AHCs have recognized that they can no longer rest on their "ivory tower" laurels. They must learn how to market themselves in a market economy.

The effect of surgery and grade on outcome of gastrointestinal stromal tumors.

HYPOTHESIS: Gastrointestinal stromal tumors (GIST) are aggressive, rare, and difficult-to-cure gastrointestinal tumors. We believe that the clinical behavior of these tumors can be predicted by reproducible prognostic factors. DESIGN AND SETTING: A retrospective review of all patients (N = 70) with GIST treated at a tertiary care center from 1973 to 1998. PATIENTS: Adequate data for evaluation were available for 69 patients. Male-female distribution was 40:29. Median age was 60 years. Median follow-up duration was 38 months. MAIN OUTCOME MEASURES: Tumor grade, stage, and histologic subtype at presentation; effect of grade, surgery and adjuvant therapy on recurrence, salvage, and survival. RESULTS: Tumor distribution included 61% in the upper, 23% in the middle, and 16% in the lower digestive tract, with a median tumor size of 7.9 cm (range, 1.8-25 cm). Tumors with more than 1 mitosis per 10 high-power fields constituted 57% of neoplasia in the series. Distant disease at initial visit occurred in 49% of patients. Complete gross resection occurred in 59% of patients. After complete resection, the 5-year survival rate was 42%, compared with 9% after incomplete resection (hazard ratio = 0.27, P<.001). Neither radiation nor chemotherapy demonstrated any significant benefit. Among 39 patients who were disease free after complete resection, 2% developed lymph node recurrence, 25% developed local recurrence, and 33% developed distant recurrences (54% liver, 20% peritoneum). By multivariate analysis the risk of local and/or distant metastases was significantly increased for tumors with more than 1 mitosis and size larger than 5 cm (P<.05). Multivariate analysis in all 69 patients revealed that incomplete resection, age greater than 50 years, non-smooth muscle histological feature, tumor with more than 1 mitosis, and tumor size larger than 5 cm significantly decreased survival. CONCLUSION: Complete gross surgical resection is presently the only means of cure for GIST. Tumors with more than 1 mitosis and a size larger than 5 cm have an especially poor prognosis, with decreased survival, and increased local and/or distant recurrence.

Tumor-influenced amino acid transport activities in zonal-enriched hepatocyte populations.

Cancer influences hepatic amino acid metabolism in the host. To further investigate this relationship, the effects of an implanted fibrosarcoma on specific amino acid transport activities were measured in periportal (PP)- and perivenous (PV)-enriched rat hepatocyte populations. Na(+)-dependent glutamate transport rates were eightfold higher in PV than in PP preparations but were relatively unaffected during tumor growth. System N-mediated glutamine uptake was 75% higher in PV than in PP preparations and was stimulated up to twofold in both regions by tumor burdens of 9 +/- 4% of carcass weight compared with hepatocytes from pair-fed control animals. Excessive tumor burdens (26 +/- 7%) resulted in hypophagia, loss of PV-enriched system N activities, and reduced transporter stimulation. Conversely, saturable arginine uptake was enhanced fourfold in PP preparations and was induced twofold only after excessive tumor burden. These data suggest that hepatic amino acid transporters are differentially influenced by cancer in a spatial and temporal manner, and they represent the first report of reciprocal zonal enrichment of system N and saturable arginine uptake in the mammalian liver.

Judging surgical research: how should we evaluate performance and measure value?

OBJECTIVE: To establish criteria to evaluate performance in surgical research, and to suggest strategies to optimize research in the future. SUMMARY BACKGROUND DATA: Research is an integral component of the academic mission, focusing on important clinical problems, accounting for surgical advances, and providing training and mentoring for young surgeons. With constraints on healthcare resources, there is increasing pressure to generate clinical revenues at the expense of the time and effort devoted to surgical research. An approach that would assess the value of research would allow prioritization of projects. Further, alignment of high-priority research projects with clinical goals would optimize research gains and maximize the clinical enterprise. METHODS: The authors reviewed performance criteria applied to industrial research and modified these criteria to apply to surgical research. They reviewed several programs that align research objectives with clinical goals. RESULTS: Performance criteria were categorized along several dimensions: internal measures (quality, productivity, innovation, learning, and development), customer satisfaction, market share, and financial indices (cost and profitability). A "report card" was proposed to allow the assessment of research in an individual department or division. CONCLUSIONS: The department's business strategy can no longer be divorced from its research strategy. Alignment between research and clinical goals will maximize the department's objectives but will create the need to modify existing hierarchical structures and reward systems. Such alignment appears to be the best way to ensure the success of surgical research in the future.

Amino acid uptake and regulation in multicellular hepatoma spheroids.

BACKGROUND: Cancer cells maintained in monolayer tissue culture are frequently used to study tumor biology and nutrient uptake, but there is a concern that this system may not fully reflect clinical tumor physiology. Because cells grown in a 3-D configuration more closely resemble an in vivo environment, a model was developed and characterized for the growth of SK-Hep human hepatoma cells in suspension as multicellular tumor spheroids (MTS). The measurement of nutrient uptake in such a system has never been established. MATERIALS AND METHODS: SK-Hep cultures were initiated as single cell suspensions and grown as MTS in siliconized spinner flasks. The transport of several individual amino acids (arginine, glutamate, leucine, alpha-(N-methylamino)isobutyric acid (MeAIB), and glutamine (GLN)) was measured in SK-Hep single cell suspensions and MTS (0. 50-0.60 mm diameter) by a radiotracer/rapid filtration technique, as was the regulation of glutamine uptake by phorbol esters. l-[(3)H]GLN uptake was also measured in larger spheroids (0.85-1.5 mm diameter). MTS cellularity was evaluated by histological examination, and single cell integrity after the transport assay was confirmed by scanning electron microscopy (SEM). RESULTS: SK-Hep MTS displayed gradients of cellular morphology and staining, with central necrosis visible at diameters >0.8 mm. Single cell suspensions endured the rapid filtration technique based on functional Na(+)-dependent uptake rates and SEM analysis. Of all amino acids tested, only GLN transport rates were visibly affected by growth format. In small MTS, Na(+)-dependent GLN uptake was diminished by 40%, but was 40-53% higher in MTS >1 mm displaying central necrosis, when compared to single cell suspensions. Likewise, slight parallel changes in glutamine transporter ATB(0) mRNA levels were observed in Northern blot analysis. Finally, phorbol ester-dependent GLN transport down-regulation (by 40-50%), previously established in SK-Hep monolayers, remained operative in all cell formats tested. CONCLUSIONS: The data suggest that the tumor microenvironment differentially impacts the uptake of specific nutrients despite the conservation of key regulatory pathways. This MTS technique may prove useful for further studies on the role of nutrient transport in nascent tumor growth.

Phorbol esters rapidly attenuate glutamine uptake and growth in human colon carcinoma cells.

BACKGROUND: The amino acid glutamine, while essential for gut epithelial growth, has also been shown to stimulate colon carcinoma proliferation and diminish differentiation. Human colon carcinomas are known to extract and metabolize glutamine at rates severalfold greater than those of normal tissues, but the regulation of this response is unclear. Previously we reported that phorbol esters regulate hepatoma System ASC/B(0)-mediated glutamine uptake and cell growth. As human colon carcinoma cells use this same transporter for glutamine uptake, the present studies were undertaken to determine whether similar regulation functions in colon carcinoma. MATERIALS AND METHODS: Human colon carcinoma cell lines (WiDr and HT29) were treated with the protein kinase C (PKC) activator phorbol 12-myristate 13-acetate (PMA) and initial-rate transport of glutamine and other nutrients was measured at specific times thereafter. Growth rates were monitored during culture +/- PMA or an excess of System ASC/B(0) substrates relative to glutamine. RESULTS: PMA treatment induced a rapid inhibition of glutamine uptake rates in WiDr and HT29 cells by 30 and 57%, respectively, after 1 h. Cycloheximide failed to block this response, indicating that the mechanism by which PMA exerts its effects is posttranslational. The inhibition of glutamine uptake by PMA was abrogated by the PKC inhibitor staurosporine, suggesting that this rapid System ASC/B(0) regulation may be mediated by a PKC-dependent pathway. PMA also significantly decreased transport via System y(+) (arginine) and System A (small zwitterionic amino acids). Chronic phorbol ester treatment inhibited WiDr cell growth, as did attenuation of System B(0)-mediated glutamine uptake with other transporter substrates. CONCLUSIONS: System ASC/B(0) uptake governs glutamine-dependent growth in colon carcinoma cell lines, and is regulated by a phorbol ester-sensitive pathway that may involve PKC. The results further establish the link between glutamine uptake and colon carcinoma cell growth, a relationship worthy of further investigation with the goal of discovering novel cancer therapeutic targets.

Lymphedema after sentinel lymph node biopsy for cutaneous melanoma: a report of 5 cases.

BACKGROUND: Sentinel lymph node (SLN) biopsy has rapidly become the procedure of choice for assessing the lymph node status of patients with 1992 American Joint Committee on Cancer stages I and II melanoma. The procedure was designed to be less invasive and, therefore, less likely to cause complications than a complete lymph node dissection. To our knowledge, this is the first report in the literature documenting extremity lymphedema following SLN biopsy. OBSERVATION: We report 5 cases of lymphedema after SLN biopsy in patients being routinely followed up after melanoma surgery at the Massachusetts General Hospital Melanoma Center, Boston. Three cases were mild, and 2 were moderate. Potential contributing causes of lymphedema were present in 4 patients and included the transient formation of hematomas and seromas, obesity, the possibility of occult metastatic melanoma, and the proximal extremity location of the primary melanoma excision. Four of the patients underwent an SLN biopsy at our institution. We used the total number of SLN procedures (N = 235) that we have performed to calculate a 1.7% baseline incidence of lymphedema after SLN biopsy. CONCLUSIONS: Sentinel lymph node biopsy can be complicated by mild and moderate degrees of lymphedema, with an incidence of at least 1.7%. Some patients may have contributing causes for lymphedema other than the SLN biopsy, but many of these causes are difficult to modify or avoid.

Hepatic glutamine transporter activation in burn injury: role of amino acids and phosphatidylinositol-3-kinase.

Burn injury elicits a marked, sustained hypermetabolic state in patients characterized by accelerated hepatic amino acid metabolism and negative nitrogen balance. The transport of glutamine, a key substrate in gluconeogenesis and ureagenesis, was examined in hepatocytes isolated from the livers of rats after a 20% total burn surface area full-thickness scald injury. A latent and profound two- to threefold increase in glutamine transporter system N activity was first observed after 48 h in hepatocytes from injured rats compared with controls, persisted for 9 days, and waned toward control values after 18 days, corresponding with convalescence. Further studies showed that the profound increase was fully attributable to rapid posttranslational transporter activation by amino acid-induced cell swelling and that this form of regulation may be elicited in part by glucagon. The phosphatidylinositol-3-kinase (PI3K) inhibitors wortmannin and LY-294002 each significantly attenuated transporter stimulation by amino acids. The data suggest that PI3K-dependent system N activation by amino acids may play an important role in fueling accelerated hepatic nitrogen metabolism after burn injury.