Use of an automated circuit for isolated limb infusion for malignancy

BACKGROUND

Isolated limb infusion (ILI) for recurrent or in-transit melanoma is an accepted technique that allows high-dose chemotherapy to be delivered to an extremity with minimal systemic toxicity. Current infusion systems have relied on manual delivery of drugs and circulation of blood during the treatment. Herein, we document our initial results with an automated circuit for ILI as an alternative to the manual technique.

METHODS

Patients undergoing ILI with an automated circuit for recurrent or advanced malignancy were identified. ILI was performed utilizing a Sarns 8000 roller pump attached to a Cobe 4:1 cardioplegia set with heat exchanger with a total priming volume of 80 ml. Melphalan (7.5 mg/L) and Dactinomycin (75 μg/L) doses which were corrected for ideal body weight were delivered via the infusion circuit after limb temperature reached 38 °C.

RESULTS

Fourteen lower extremity infusion procedures were performed in 10 patients. Successful infusion procedures were completed in all patients using the automated circuit. Constant flow rates of 50-70 cc/minute were achievable with the automated circuit. Acute toxicity and clinical results were similar to that reported with manual delivery systems.

CONCLUSION

ILI for advanced malignancy utilizing an automated circuit is feasible and safe. This automated system offers a safe and reliable alternative to the manual infusion technique.

The hottest sentinel lymph node is not always the positive node

The technique of identifying the sentinel lymph node (SLN) varies from each individual institution. Generally, the highest isotope count in a lymph node is considered the SLN, whereas other radioactive nodes might also be removed. The purpose of our study was to determine if the hottest node was always the tumor-containing node. Two hundred forty-seven breast cancer patients underwent SLN biopsy from April 1998 to April 2002. Lymphatic mapping involved a radiocolloid injection and lymphoscintigraphy followed by intraoperative assessment with a hand-held gamma probe. All SLN(s) with radioactive counts 10 per cent or more of the ex vivo counts of the most radioactive SLN were removed. The SLN were sliced at 2-mm intervals with 4-microm step-sections (92-microm spacing) and evaluated by microscopy and immunohistochemistry. One hundred twenty (49%) of the 247 patients had 2 or more nodes resected. Of these 120 patients, 33 (28%) had a tumor-bearing node. In 25 (74%) cases, the tumor-bearing node was the most radioactive; however, in 8 (26%) cases, the positive node was a lesser reactive node. Although the most radioactive node in a draining basin is considered the SLN, this is often not the metastatic node. Therefore, all nodes with significant radioactive counts must be removed to ensure accurate staging.

Local excision and postoperative radiation therapy for rectal adenocarcinoma

Sixty-seven patients with early-stage adenocarcinoma of the rectum who had lesions thought to be unsuitable for either local excision alone or endocavitary irradiation were treated with local excision followed by postoperative radiation therapy. The purpose of this study was to evaluate the effectiveness of local excision followed by radiation therapy for treatment of rectal adenocarcinoma. The patients were treated between 1974 and 1999; follow-up time was 6 to 273 months (median, 65 months). All living patients had follow-up for at least 2 years. The indications for postoperative irradiation included equivocal or positive margins, invasion of the muscularis propria, endothelial-lined space invasion, poorly differentiated histology, and perineural invasion. Cox proportional hazards regression analysis was performed using six explanatory variables including tumor size, configuration (exophytic vs. ulcerative), histologic differentiation, pathologic T stage, endothelial-lined space invasion, and margin status. The time interval between treatment and development of recurrent disease was in the range of 11 to 48 months. The 5-year results were as follows: local-regional control, 86%; ultimate local-regional control, 93%; distant metastasis-free survival, 93%; absolute survival, 80%; and cause-specific survival, 90%. When the Cox proportional hazards regression analysis was performed for these endpoints, margin status influenced absolute survival (P = 0.0074), cause-specific survival (P = 0.0405), and ultimate local-regional control (P = 0.0439). Tumor configuration marginally influenced cause-specific survival (P = 0.0577). None of the variables had an influence on the endpoints' local-regional control, ultimate local-regional control with sphincter preservation, or distant metastasis. Five patients (7%) had severe complications; no complication was fatal. Local excision and postoperative radiation therapy results in a high probability of local-regional control and survival for selected patients with relatively early-stage rectal adenocarcinoma. Patients with ulcerative tumors may have a lower likelihood of cause-specific survival.

Competency-based student self-assessment on a surgery rotation

BACKGROUND

Although self-assessment is an essential component of self-directed adult learning, few data exist regarding the ability of medical students to perform this important task. Therefore, the purpose of this study was to evaluate the ability of medical students to perform self-assessment during a third-year surgery clerkship.

METHODS

Sixty-eight (34 male, 34 female) third-year medical students assessed their progress at the midpoint of an 8-week surgery clerkship using an 11-item, competency-based evaluation. Students compared perceptions of their performance with a faculty member's assessment using the identical evaluation form.

RESULTS

Male students tended to overestimate their midclerkship performance compared with faculty formative and summative evaluations (3.31 +/- 0.03 vs 3.23 +/- 0.03 and 3.28 +/- 0.03) although this did not reach statistical significance. Female students significantly underestimated their midclerkship performance compared with faculty formative and summative evaluations (3.06 +/- 0.03 vs 3.40 +/- 0.03 and 3.45 +/- 0.03, P < 0.05 vs faculty evaluations). Preclerkship academic performance (first- and second-year grade point averages and NBME Part 1 scores) was not predictive of student self-assessment. Finally, women statistically outperformed men on the surgery clerkship (86.6% +/- 0.75 vs 83.2% +/- 1.20, P < 0.05 vs male students).

CONCLUSIONS

Female students tend to underestimate their midclerkship performance compared with male students on a surgery rotation. Despite lower self-assessment, female students actually outperform male students. Women may underreport their capabilities when compared with men as a result of gender differences in socialization. These gender differences in self-assessment may be important to recognize when faculty provide feedback to students.

Institutional validation of breast cancer treatment guidelines

Several groups have developed clinical guidelines for the management of breast cancer, yet little data exist regarding their validation. Therefore, we examined the effect of published National Comprehensive Cancer Network (NCCN) guidelines for invasive breast cancer on survival, quality of life (QOL), and hospital cost. From 260 consecutive breast cancer patients, 129 patients were identified for analysis: 93 patients (72%) were treated according to the guidelines (NCCN+), while the treatment of 36 patients (28%), with a similar stage distribution, deviated from the guidelines (NCCN-). Patients were excluded from analysis with a diagnosis of carcinoma in situ, inflammatory cancer, stage IV disease, and comorbid conditions that affected treatment. The 5-year survival was 87.6% for the NCCN+ patients versus 83.3% for NCCN- patients (P = 0.319 by Kaplan-Meier). Twelve QOL parameters were evaluated using a Likert-type scale (1 = severe and 5 = none). NCCN+ patients had a cumulative QOL score of 4.18 +/- 0.08 versus 4.24 +/- 0.14 for NCCN- patients (P = 0.745). Treatment-related costs were $20,300 +/- 1800 for NCCN+ patients versus $59,700 +/- 25,200 for NCCN- patients (P = 0.016 by t test). Although deviation from NCCN breast cancer guidelines had no effect on perceived quality of life or survival, there was a significant decrease in cost in the NCCN+ group. These findings suggest that adherence to NCCN guidelines can significantly reduce the cost of breast cancer care without adversely affecting either survival or quality of life.

Nuclear factor-kappa B is upregulated in colorectal cancer

BACKGROUND

Chemoresistance may involve the anti-apoptotic transcriptional regulator, nuclear factor-kappa B (NF-kappa B). The purpose of this study was to determine whether chemotherapy induces NF-kappa B activation in a human colon cancer cell line (SW48) and whether NF-kappa B is constitutively activated in colorectal cancer.

METHODS

SW48 cells were incubated with gemcitabine hydrochloride (Gemzar) in the presence and absence of the 26s proteasome inhibitor, MG132, and NF-kappa B binding (electrophoretic mobility shift assay), DNA synthesis (tritiated thymidine uptake), cell viability (3-[4,5-dimethylthiazol-2-yl]-diphenyl-tetrazolium bromide assay), and apoptosis (caspase-3 activity) were measured at 24 hours. NF-kappa B binding (electrophoretic mobility shift assay) was also assayed in 10 colorectal cancer tumors.

RESULTS

SW48 cells demonstrated constitutive NF-kappa B binding that was enhanced by gemcitabine hydrochloride in a dose-dependent manner. MG132 inhibited NF-kappa B binding and enhanced gemcitabine hydrochloride's inhibition of DNA synthesis (gemcitabine hydrochloride = 73% +/- 1.4% vs gemcitabine hydrochloride + MG132 = 6% +/- 0.4%, P <.05), cell killing (gemcitabine hydrochloride = 87% +/- 2.0 vs gemcitabine hydrochloride + MG132 = 25% +/- 1.3%, P <.05), and caspase-3 activity (gemcitabine hydrochloride = 870 +/- 17.4 vs gemcitabine hydrochloride + MG132 = 1075 +/- 20.4, P <.05). NF-kappa B binding was increased in 8 of 10 colorectal cancer tumors compared with adjacent normal mucosa.

CONCLUSIONS

Gemcitabine hydrochloride enhances NF-kappa B binding in a colorectal cancer cell line, whereas inhibition of NF-kappa B enhances gemcitabine hydrochloride's antitumor activity. NF-kappa B is also activated in human colorectal cancer. NF-kappa B may identify chemoresistant tumors, whereas inhibition of NF-kappa B may be a novel, biologically based therapy. (Surgery 2001;130:363-9).

Adenoviral delivery of human and viral IL-10 in murine sepsis

Adenovirus (Ad) gene therapy has been proposed as a drug-delivery system for the targeted administration of protein-based therapies, including growth factors and biological response modifiers. However, inflammation associated with Ad transduction has raised concern about its safety and efficacy in acute inflammatory diseases. In the present report, intratracheal and i.v. administration of a first-generation adenoviral recombinant (E1,E3 deleted) either containing an empty cassette or expressing the anti-inflammatory cytokines viral or human IL-10 (IL-10) was administered to mice subjected to zymosan-induced multisystem organ failure or to acute necrotizing pancreatitis. Pretreatment of mice with the intratracheal instillation of Ad expressing human IL-10 or viral IL-10 reduced weight loss, attenuated the proinflammatory cytokine response, and reduced mortality in the zymosan-induced model, whereas pretreatment with a control adenoviral recombinant did not significantly exacerbate the response. Pretreatment of mice with pancreatitis using adenoviral vectors expressing IL-10 significantly reduced the degree of pancreatic and liver injury and liver inflammation when administered systemically, but not intratracheally. We conclude that adenoviral vectors can be administered prophylactically in acute inflammatory syndromes, and expression of the anti-inflammatory protein IL-10 can be used to suppress the underlying inflammatory process.

Extended lung expression and increased tissue localization of viral IL-10 with adenoviral gene therapy

IL-10 is a pleiotropic cytokine that acts as an important regulator of macrophage, T cell, and natural killer cell functions. Human IL-10 (hIL-10) has both stimulatory and inhibitory effects on a wide variety of cell types. Viral IL-10 (vIL-10) possesses only a subset of hIL-10's activities, predominantly its suppression of cytokine synthesis by T helper type 1 clones. In the present report, we evaluated tissue accumulation and biological activity of hIL-10 and vIL-10 in vivo in individual organs by using a first-generation adenoviral (Ad) vector administered intratracheally and intravenously. We report the observation that Ad vectors delivering vIL-10, but not hIL-10, are associated with prolonged expression in the lung (>42 days) when delivered intratracheally. In contrast, there was no prolongation in vIL-10 expression when Ad vectors were intravenously administered, although vIL-10 levels in the tissue, but not serum, were markedly increased relative to hIL-10. Moreover, we report an augmented capacity of expressed vIL-10 versus hIL-10 to suppress the acute inflammatory responses in the lung to intratracheal administration of Ad. These findings confirm fundamental differences in Ad-induced expression of vIL-10 and hIL-10 when administered to the lungs. The results further suggest that Ad vectors expressing vIL-10 may have a role as anti-inflammatory agents in the treatment of acute and chronic lung inflammation.

CONSERVATIVE TREATMENT OF RECTAL ADENOCARCINOMA

Endocavitary radiotherapy and transrectal excision are highly effective treatments for properly selected patients with favorable early-stage rectal adenocarcinoma. The likelihood of local control and survival after treatment with either modality is similar, and differences among various series probably reflect selection. The parameter most predictive of local control and survival in the authors' series was tumor configuration. As has been previously observed, "selection is the silent partner of success." Suitable candidates for endocavitary radiotherapy or wide local excision are patients whose tumors are 3 cm or less in diameter, well-to-moderately differentiated, exophytic, mobile, limited to the submucosa on transrectal ultrasound, and within 10 cm of the anal verge. The advantages of endocavitary irradiation are (1) it is an outpatient procedure, (2) it does not require anesthesia, and (3) it is less expensive than transrectal excision. The advantages of transrectal excision are (1) it may be performed during one brief hospitalization (as opposed to four outpatient visits), and (2) a small subset of patients will have pathologic findings predicting an increased risk of regional lymph node involvement, revealing the need to treat the nodes with external-beam radiotherapy. A disadvantage of wide local excision is that some patients who would be suitable for a local procedure alone must be subjected to a course of external-beam radiotherapy when they are found to have equivocal or positive margins. Patients who are treated with transrectal excision and external-beam radiotherapy have less favorable lesions and are not comparable with patients who are treated with endocavitary radiotherapy or wide local excision alone. They are best compared with patients who have undergone major surgery consisting of abdominoperineal resection or low anterior resection. Because the risk of positive nodes is significantly increased with adverse pathologic findings such as poor differentiation, invasion of the muscularis propria, and endothelial-lined space invasion, a subset of these patients treated with wide local excision would have positive nodes. This subset of patients is not comparable with patients with stage pT1N0 and pT2N0 tumors treated with major surgery. The latter group of patients undergo complete surgical staging, whereas the pathologic staging for patients who undergo wide local excision and radiotherapy is limited to the extent of the primary tumor. With this caveat in mind, wide local excision and radiotherapy seem to result in locoregional control and survival rates similar to the rates obtained with major surgery for patients with pT1 and pT2 cancers (Table 5). Patients who should receive postoperative irradiation have tumors that exhibit one or more of the following characteristics: size greater than 3 cm in diameter, poorly differentiated, invasion of the muscularis propria, endothelial-lined space invasion, fragmented resection, equivocal or positive margins, or perineural invasion. Patients with gross residual disease are not suitable candidates for radiotherapy and require further surgery. The authors' policy is to treat these patients with chemoradiation followed by resection. Patients thought to have transmural invasion before treatment are probably best treated with preoperative chemoradiation combined with major surgery, although a subset of patients can be downstaged and rendered suitable for a wide local excision.

Treatment of paracolostomy abscesses without proximal diverting colostomy: report of two cases

Two patients had paracolostomy abscesses limited to the abdominal wall. Adequate drainage was obtained surgically using local anesthesia, but wound contamination from the fecal stream continued. Intravenous hyperalimentation and/or elemental diet reduced fecal volume, promoted wound healing and weight gain, and prevented the need for a proximal defunctionalizing colostomy. During follow-up periods of more than ten months, colostomy revision has not been necessary.

Glucocorticoid and Fas ligand induced mucosal lymphocyte apoptosis after burn injury

BACKGROUND

The purpose of this study was to examine the effects of a steam burn injury on apoptosis in gut-associated lymphoid tissue and to determine whether endogenous glucocorticoid and Fas ligand signaling were involved in this process.

METHODS

Histologic analysis, in situ deoxynucleotidyl transferase dUTP nick-end labeling staining and annexin V and 7-amino-actinomycin-D flow cytometry of lymphocyte populations were evaluated in intraepithelial lymphocytes and Peyer's patch. Additional mice were pretreated with a glucocorticoid receptor antagonist (mifepristone) before the steam burn. Similarly, C3H/HeJ-FasL(gld) mice lacking functional Fas ligand were also studied.

RESULTS

Apoptosis was significantly increased in intraepithelial lymphocytes and Peyer's patch after the burn injury. Mifepristone pretreatment significantly reduced apoptosis in both T- and B-cell populations in intraepithelial lymphocytes after the burn injury. In contrast, the increased apoptosis seen in B-cells from Peyer's patch was not seen in C3H/HeJFasL(gld) mice, whereas the increased apoptosis in CD8+ T-cells was unaffected.

CONCLUSION

Both corticosteroids and FasL contribute to the apoptosis in gut-associated lymphoid tissues early after burn injury.

The relationship between visceral ischemia, proinflammatory cytokines, and organ injury in patients undergoing thoracoabdominal aortic aneurysm repair

OBJECTIVES

Plasma proinflammatory, anti-inflammatory cytokine, and soluble tumor necrosis factor (TNF) receptor concentrations were examined in hospitalized patients after abdominal and thoracoabdominal aortic aneurysm (TAAA) repair, with and without left atrial femoral bypass. Changes in plasma cytokine concentrations were related to the duration of visceral ischemia and the frequency rate of postoperative, single, or multiple system organ dysfunction (MSOD).

DESIGN

Prospective, observational study.

SETTING

Two academic referral centers in the United States and The Netherlands.

PATIENTS

We included 16 patients undergoing TAAA repair without left atrial femoral bypass, 12 patients undergoing TAAA repair with left atrial femoral bypass, and nine patients undergoing infrarenal aortic aneurysm repair.

MEASUREMENTS AND MAIN RESULTS

Timed, arterial blood sampling for proinflammatory and anti-inflammatory cytokine and soluble TNF receptor concentrations (p55 and p75), and prospective assessment of postoperative single and MSOD. Plasma appearance of TNF-alpha, interleukin (IL)-6, IL-8, and IL-10 peaked 1 to 4 hrs after TAAA repair, and concentrations were significantly elevated compared with infrarenal abdominal aortic aneurysm repair (p < .05). Left atrial femoral bypass significantly reduced the duration of visceral ischemia (p < .05) and the systemic TNF-alpha, p75, and IL-10 responses (p < .05). Plasma TNF-alpha concentrations >150 pg/mL were more common in patients with extended visceral ischemia times (>40 mins). Additionally, patients with early peak TNF-alpha concentrations >150 pg/mL and IL-6 levels >1,000 pg/mL developed MSOD more frequently than patients without these elevated plasma cytokine levels (both p < .05).

CONCLUSIONS

Thoracoabdominal aortic aneurysm repair results in the increased plasma appearance of TNF-alpha, IL-6, IL-8, IL-10, and shed TNF receptors. The frequency and magnitude of postoperative organ dysfunction after TAAA repair is associated with an increased concentration of the cytokines, TNF-alpha, and IL-6 and the increased plasma levels of these cytokines appear to require extended visceral ischemia times.

Lipopolysaccharide and D-galactosamine-induced hepatic injury is mediated by TNF-alpha and not by Fas ligand

Tumor necrosis factor (TNF)-alpha and Fas ligand (FasL) are trimeric proteins that induce apoptosis through similar caspase-dependent pathways. Hepatocytes are particularly sensitive to inflammation-induced programmed cell death, although the contribution of TNF-alpha and/or FasL to this injury response is still unclear. Here, we report that D-galactosamine and lipopolysaccharide-induced liver injury in C57BL/6 mice is associated with increased hepatic expression of both TNF-alpha and FasL mRNA. Pretreatment of mice with a TNF-binding protein improved survival, reduced plasma aspartate aminotransferase concentrations, and attenuated the apoptotic liver injury, as determined histologically and by in situ 3' OH end labeling of fragmented nuclear DNA. In contrast, pretreatment of mice with a murine-soluble Fas fusion protein (Fasfp) had only minimal effect on survival, and apoptotic liver injury was either unaffected or exacerbated depending on the dose of Fasfp employed. Similarly, mice with a spontaneous mutation in FasL (B6Smn.C3H-Fasl(gld) derived from C57BL/6) were equally sensitive to D-galactosamine/lipopolysaccharide-induced shock. We conclude that the shock and apoptotic liver injury after D-galactosamine/lipopolysaccharide treatment are due primarily to TNF-alpha release, whereas increased FasL expression appears to contribute little to the mortality and hepatic injury.

Glucocorticoid-induced, caspase-dependent organ apoptosis early after burn injury

Immune suppression and increased apoptotic loss of circulating lymphocytes have been reported after burn injury. However, little is known about the underlying mechanisms responsible for the increased apoptosis of lymphoid and parenchymal cells in solid organs and the role played by inflammatory mediators, such as tumor necrosis factor-alpha (TNF-alpha) and Fas ligand (FasL), as well as by glucocorticoids. To evaluate the role of endogenously produced glucocorticoids and FasL, mice subjected to a 20% steam burn were pretreated with a glucocorticoid receptor antagonist (mifepristone) or a neutralizing murine Fas fusion protein. Three and twenty-four hours after burn injury, histological analysis, caspase-3 activity, and in situ terminal deoxynucleotidyl transferase dUTP nick-end labeling staining and phenotyping of lymphocyte populations for apoptosis were evaluated. Burn injury increased the number of apoptotic cells and caspase-3 activity in thymus and spleen, but not in other solid organs. Increased apoptosis was seen in several T and B cell populations from both thymus and spleen. Mifepristone pretreatment significantly reduced the apoptosis and caspase-3 activity after burn injury, whereas blocking FasL activity had only minimal effects. We conclude that corticosteroids, and not FasL, are primarily responsible for the increased caspase-3 activity and apoptosis in thymus and spleen cell populations early after burn injury.

TNF-alpha receptor signaling and IL-10 gene therapy regulate the innate and humoral immune responses to recombinant adenovirus in the lung

Recombinant adenovirus-mediated gene therapy has demonstrated great promise for the delivery of genes to the pulmonary epithelium. However, dose-dependent inflammation and local immune responses abbreviate transgene expression. The purpose of these studies was to determine the role of TNF-alpha and individual TNF receptor signaling to adenovirus clearance and immune responses, and whether coexpression of human IL-10 could reduce inflammation and extend the duration of transgene expression in the lung. beta-Galactosidase expression in mice receiving intratracheal instillation of Adv/beta-gal (adenovirus construct expressing beta-galactosidase) was transient (less than 14 days), but a significant early increase of beta-galactosidase expression was seen in mice lacking either or both TNF-alpha receptors. Absence of TNF-alpha or the p55 receptor significantly attenuated the Ab response to both adenovirus and beta-galactosidase. Human IL-10 expression in the lung suppressed local TNF-alpha production following AdV/hIL-10 (adenovirus construct expressing human IL-10) delivery, but did not lead to increased or prolonged transgene expression when coexpressed with beta-galactosidase. Expression of human IL-10 following AdV/hIL-10 instillation extended at least 14 days, was nonimmunogenic, and suppressed the development of neutralizing Abs against adenoviral proteins as well as against human IL-10. We conclude that TNF-alpha signaling through both the p55 and p75 receptor plays important roles in the clearance of adenoviral vectors and the magnitude of the humoral immune response. Additionally, although coexpression of human IL-10 with beta-galactosidase had only modest effects on transgene expression, we demonstrate that AdV/hIL-10 is well tolerated, has extended expression compared with beta-galactosidase, and is nonimmunogenic in the lung.

Discordant tumor necrosis factor-alpha superfamily gene expression in bacterial peritonitis and endotoxemic shock

BACKGROUND

Tumor necrosis factor-alpha (TNF-alpha) is a member of a large family of predominantly homotrimeric type II membrane-associated proteins with both proinflammatory and apoptosis-inducing properties. Although TNF-alpha expression has been studied extensively, little is known about the expression of other members of the TNF-alpha superfamily during acute inflammatory processes.

METHODS

TNF-alpha, Fas ligand (FasL), and TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) messenger RNA (mRNA) expression were examined in liver, lung, spleen, and kidney after either a cecal ligation and puncture or endotoxemic shock with use of semiquantitative reverse transcriptase-polymerase chain reaction.

RESULTS

Cecal ligation and puncture increased TNF-alpha mRNA in lung and liver (both P < .05) within 3 hours, which was paralleled by increased FasL mRNA. In the spleen TNF-alpha and FasL mRNA significantly declined (both P < .05). In contrast to TNF-alpha and FasL, TRAIL mRNA levels were unchanged in all organs except lung, where it was reduced at 24 hours (P < .05). Endotoxemic shock also increased lung TNF-alpha and FasL mRNA levels (both P < .05).

CONCLUSIONS

In acute inflammatory processes TNF-alpha and FasL mRNA increase concordantly in several solid organs. In contrast, TRAIL mRNA levels do not consistently change during these acute inflammatory processes, suggesting that its expression is under independent and discordant regulatory control.

Application of gene therapy to acute inflammatory diseases

The application of gene therapy to acute inflammation has not received as much research attention as has the treatment of genetically-based diseases, cancer, and viral infections. However, gene therapy as a drug delivery system offers several theoretical and practical advantages over current protein delivery systems. These include the ability to target therapies to individual tissues or cell types, to locally produce proteins that can act intracellularly or in an autocrine, juxtacrine, or paracrine fashion, and to sustain new protein synthesis for periods up to several weeks after a single administration. Although retrovirus, herpes simplex, and adeno-associated virus have been proposed for gene therapy in cancer and in genetic diseases, nonviral and adenovirus approaches appear most applicable as drug delivery systems due to their rapid onset and short duration of transgene expression. The relative modest transduction efficiencies obtained at present with nonviral approaches, and the inherent inflammatory properties of first-generation adenovirus constructs, however, have limited their usefulness to date. The present review discusses the theoretical and practical benefits of specific gene therapy approaches for the treatment of acute inflammatory diseases, as well as our experiences with liposome:plasmid DNA and adenovirus-based approaches. Although a number of technical and theoretical hurdles remain before it can be evaluated in humans with acute inflammation, gene therapy offers a novel approach for the treatment of acute inflammation, and will likely enter the armamentarium of critical care physicians in the near future.

Characterization in vitro and in vivo of hammerhead ribozymes directed against murine tumor necrosis factoralpha

A hammerhead ribozyme directed against murine TNFalpha (mTNFalpha) mRNA has been constructed. In vitro studies showed that this ribozyme was released from the parent molecule by flanking cis-acting hammerhead and hairpin ribozymes. This same anti-mTNFalpha ribozyme specifically cleaved both synthetically derived substrate RNA and mTNFalpha mRNA within a pool of total cellular RNA. Endogenous delivery of this anti-mTNFalpha ribozyme via the self-cleaving cassette reduced mTNFalpha mRNA and protein levels in lipopolysaccharide (LPS)-stimulated, stably transfected murine macrophage RAW 264.7 cells. When complexed to liposomes and exogenously delivered to mouse peritoneal macrophages, the same ribozyme, with and without the cis-acting ribozymes, reduced mTNFalpha protein levels. However, an irrelevant ribozyme delivered in an identical fashion was also effective at reducing mTNFalpha protein levels. These data suggest that anti-mTNFalpha ribozymes can be constructed which efficiently cleave mTNFalpha mRNA, but irrelevant RNA/liposome complexes also effectively limit TNFalpha mRNA expression and can mimic functional ribozyme activity under in vitro conditions.

Surgical oncology: a specialty in evolution

Surgical oncology has established its role in the multidisciplinary care of the cancer patient. Surgical oncology fellowships are organized to teach multimodality treatment. The typical fellow has completed 6 years of general surgery residency and 1 year in the laboratory with the resultant eight publications. Data compiled from the review of two Society of Surgical Oncology-approved fellowship programs, the Surgical Residency Review Committee and the American Board of Surgery, indicate that the majority of fellows join academic faculties and enhance the training of general surgeons, who, in turn, have the major responsibility for oncologic care of the population at large.

The effect of the duration and structure of a surgery clerkship on student performance

The emphasis on a generalist professional education has led to shortening and restructuring of the surgery clerkship in the curricula of many medical schools. Little data exist regarding the effect of these changes on student performance. Therefore, we examined the effect of the length, timing, and content of the third year surgery rotation on several clerkship and postclerkship performance measures of 487 students from July 1994 to July 1998. In addition, students' perceptions regarding their ability to understand surgical disease topics were surveyed. The 8-week clerkship (n = 232) was associated with higher NMBE surgery test scores (510.5 +/- 6.3 versus 457.4 +/- 10.0, P < 0.05) resulting in higher final clerkship grades (5.15 +/- 0.04 versus 4.87 +/- 0.03, P < 0.05). Although clerkship length had no significant effect on USMLE step 2 total or surgery subsection scores, the longer clerkship was associated with higher total (70.6 +/- 0.37 versus 68. 8 +/- 0.50, P < 0.05) and abdominal pain station (81.87 +/- 0.71 versus 79.54 +/- 0.73, P < 0.05) OCSE scores. Students rotating on surgery during the second half of third year (n = 233) had higher NMBE surgery test scores (513.1 +/- 8.9 versus 460.5 +/- 11.2, P < 0. 05) and final grades (5.17 +/- 0.03 versus 4.81 +/- 0.04, P < 0.05). Although the timing of the surgery clerkship did not significantly affect total OSCE scores, students who rotated on surgery in the second half of third year performed significantly better year on the abdominal pain OSCE station (80.47 +/- 0.92 versus 76.49 +/- 1.27, P < 0.05). Students who rotated on general surgery (n = 298) performed significantly better on the NBME surgery test (525.6 +/- 6.0 versus 459.6 +/- 9.1, P < 0.05), although this did not significantly affect the final grade. Although general versus subspecialty surgery rotation did not significantly affect total OSCE scores, students rotating on general surgery performed significantly better on the abdominal pain OSCE station (81.21 +/- 0.91 versus 78.17 +/- 0.32, P < 0.05). The length, timing, and content of the third year surgery rotation had no significant effect on performance on the oral examination. Students who had a 6-week clerkship and students who lacked exposure to general surgery felt their surgery rotation failed to prepare them to understand a number of surgical topics as well as students who had an 8-week clerkship or students who rotated on general surgery. The length, timing, and content of the surgery clerkship affect some clerkship performance measures and student perceptions of their understanding of surgical disease topics. While cognitive differences related to clerkship length are no longer detectable at the end of the third year of medical school, differences related to the acquisition of some clinical skills persist after the surgery clerkship.

Caspase-3-dependent organ apoptosis early after burn injury

OBJECTIVE

To examine the role played by endotoxin, tumor necrosis factor-alpha (TNF-alpha), and caspase-3 in the increased apoptosis seen in solid organs in the early period after a burn injury.

SUMMARY BACKGROUND DATA

Burn injury is often associated with immune suppression. Bacterial translocation and systemic endotoxemia have been reported after a burn injury, and caspase-3 activation due to TNF-alpha and Fas ligand (FasL) are presumed to initiate apoptosis. We hypothesized that endotoxin-induced TNF-alpha expression and caspase-3 activation could be the stimulus for the apoptosis after burn injury.

METHODS

A 20% full-thickness scald burn was used in C57BL/6 mice. Three hours after burn injury, tissue samples were obtained from the thymus, lung, liver, and spleen. Lipopolysaccharide-nonresponsive (C3H/HeJ) and TNFalpha null B6x129tnf-/- mice were also used. To detect apoptosis, hematoxylin and eosin stain, in situ TUNEL, DNA extraction, and gel electrophoresis were all performed. Caspase-3 activity and TNF-alpha and FasL mRNA were also measured.

RESULTS

Increased apoptosis and caspase-3 activity were observed in the thymus and spleen 3 hours after burn injury but were not seen in liver or lung. In the thymus and spleen, increased expression of FasL mRNA was also observed, whereas increased TNF-alpha mRNA was not. Increased apoptosis in thymus and spleen were also observed in C3H/HeJ and B6x129tnf-/- mice after burn injury. An inhibitor of the caspase-3 (Z-VAD-fmk) reduced apoptosis in both thymus and spleen.

CONCLUSIONS

In the early period after a burn injury, increased apoptosis is observed primarily in the lymphoid organs and is independent of endotoxin or TNF-alpha. The increased caspase-3 activity in thymus and spleen contributes to apoptosis in these organs.

Recent advances in the treatment and outcome of locally advanced rectal cancer

OBJECTIVE

To compare the outcomes of treatment of locally advanced rectal cancer of the early era (1975-1990) with those of the late era (1991-1997).

BACKGROUND

Preoperative therapy has been used in locally advanced rectal cancer to preserve sphincter function, decrease local recurrence, and improve survival. At the University of Florida, preoperative radiation has been used since 1975, and it was combined with chemotherapy beginning in 1991.

METHODS

The records of 328 patients who underwent preoperative radiation or chemoradiation followed by complete resection for locally advanced rectal cancer defined as tethered, annular, or fixed tumors were reviewed. The clinicopathologic characteristics, adjuvant treatment administered, surgical procedures performed, and local recurrence-free and overall survival rates were analyzed.

RESULTS

There were 219 patients in the early era and 109 in the late era. No significant differences were seen in patients (age, gender, race) or tumor characteristics (mean distance from the anal verge, annularity, fixation). Preoperative radiation regimens were radiobiologically comparable. No patient in the early era received preoperative chemotherapy, compared with 64 in the late era. Of those receiving any pre- or postoperative chemotherapy, three patients received chemotherapy in the early era, compared with 76 in the late era. Sphincter-preserving procedures increased from 13% in the early era to 52% in the late era. Pathologic downstaging for depth of invasion increased from 42% to 58%, but lymph node negativity remained similar. The 1-, 3-, and 5-year local recurrence-free survival rates were comparable. However, in the late era, 1-, 3-, and 5-year overall survival rates improved significantly compared with those of the early era, and also compared with each of the preceding 5-year intervals.

CONCLUSION

The addition of a chemotherapy regimen to preoperative radiation therapy improves survival over radiation therapy alone. Likewise, an improvement in downstaging is associated with an increase in sphincter-preserving procedures.

Stereotactic core biopsy reduces the reexcision rate and the cost of mammographically detected cancer

The management of patients with mammographic abnormalities is rapidly shifting from needle-localized surgical biopsy (NLB) to stereotactic core biopsy (SCB). The precise role of SCB in the management of nonpalpable breast cancer remains to be defined. The purpose of this study was to compare SCB to NLB in the diagnosis of mammographically detected breast cancer in women who underwent breast-conserving surgery. The records of all patients with nonpalpable breast cancer who underwent breast-conserving surgery from 1/1/95 to 6/1/97 were analyzed with respect to method of diagnosis, time interval from detection to diagnosis and breast-conserving surgery, volume of breast tissue excised, margin status and reexcision rate, number of surgical procedures, and total charges and costs per patient. During a 30-month period, 117 patients with nonpalpable breast cancer underwent breast-conserving surgery. The diagnosis was made by NLB in 69 patients and SCB in 48 patients. The time from detection to diagnosis and breast-conserving surgery was 1.7 +/- 0.5 and 8.1 +/- 1.2 days for SCB patients and 6. 8 +/- 1.3 and 16.9 +/- 2.3 days for NLB patients (P < 0.01). The volume of breast tissue removed was 117.9 +/- 5.6 cm3 for SCB patients versus 75.2 +/- 2.9 cm3 for NLB patients (P < 0.01). Three SCB patients (6%) had positive margins, while 38 NLB patients (55%) had positive margins (P < 0.01). Only 1 SCB patient (2%) was reexcised, while 34 NLB patients (50%) were reexcised (P < 0.01). Eighty-nine percent of SCB patients had a single surgical procedure compared to 39% of NLB patients (P < 0.001). Patients who underwent SCB had reduced total charges and total costs per patient compared to NLB patients ($11,700 +/- $554 and $3537 +/- $167 per SCB patient versus $15,654 +/- $706 and $4853 +/- $198 per NLB patient, P < 0. 0001). Stereotactic core biopsy shortens the time from detection at mammography to diagnosis and breast-conserving therapy, permits appropriate discussion of treatment alternatives, reduces the positive margin rate and reexcision rate, and may represent a significant cost savings in the management of nonpalpable breast cancer.

Leptin produces anorexia and weight loss without inducing an acute phase response or protein wasting

The ob gene product leptin is known to produce anorexia and loss of body fat when chronically administered to both lean and genetically obese mice. The current study was undertaken to examine whether administration of recombinant leptin in quantities sufficient to produce decreases in food intake and body weight and alterations in body composition would elicit either an hepatic acute phase protein response or preferential loss of carcass lean tissue. Mice were administered increasing quantities of recombinant human leptin or human tumor necrosis factor-alpha as a positive control. Although leptin (at 10 mg/kg body wt) produced significant anorexia and weight loss (both P < 0.05), human leptin administration did not appear to induce an hepatic acute phase protein response in either lean or genetically obese mice, as determined by protein synthetic rates in the liver or changes in the plasma concentration of the murine acute phase protein reactants, amyloid A, amyloid P, or seromucoid (alpha1-acid glycoprotein). In addition, human leptin administration did not induce a loss of fat-free dry mass (protein) in lean or obese animals. The findings suggest that at doses adequate to alter food intake and body weight leptin is not a significant inducer of the hepatic acute phase response nor does leptin promote the preferential loss of somatic protein characteristic of a chronic inflammatory process.

Transfection of the type II TGF-beta receptor into colon cancer cells increases receptor expression, inhibits cell growth, and reduces the malignant phenotype

OBJECTIVE

To determine if transfection of SW48 colon cancer cells with the type II transforming growth factor-beta (TGF-beta) receptor restores growth inhibition and reverses the in vitro and in vivo malignant phenotype.

SUMMARY BACKGROUND DATA

The authors have previously shown that SW48 colon cancer cells that are replication error positive in both alleles lack functional cell surface TGF-beta type I (RI) and type II (RII) receptors and are insensitive to TGF-beta1-induced growth inhibition.

METHODS

SW48 cells were stably transfected with the cDNA for the normal type II TGF-beta receptor (RII). Once transfected, the cells were evaluated for in vitro phenotypic changes and in vivo changes in tumor growth.

RESULTS

Denaturing sequencing gel electrophoresis of the reverse transcriptase-polymerase chain reaction product from SW48 cells revealed that the RII coding sequence contained a single base deletion mutation. When these cells were transfected with normal RII cDNA, Northern and Western blot analyses revealed increased levels of RII mRNA and protein. Affinity labeling techniques revealed that RII-transfected SW48 cells produced functional RI and RII protein. Transfection of SW48 cells also led to changes in cell phenotype, as shown by inhibition of both in vitro growth rate and incorporation of [3H]-thymidine. SW48 cells expressing normal RII also exhibited reduced cloning efficiency in semisolid medium and reduced growth as a xenograft in NOD/LtSz-scid/J mice.

CONCLUSIONS

The results confirm that RII is a tumor-suppressor protein that is required for TGF-beta-induced growth inhibition in SW48 colon cancer cells.

Increased leptin expression in mice with bacterial peritonitis is partially regulated by tumor necrosis factor alpha

Plasma leptin and ob gene mRNA levels were increased in mice following bacterial peritonitis, and blocking an endogenous tumor necrosis factor alpha (TNF-alpha) response blunted the increase. However, plasma leptin concentrations did not correlate with the associated anorexia. We conclude that leptin expression is under partial regulatory control of TNF-alpha in peritonitis, but the anorexia is not dependent on increased leptin production.

Historical perspective on nutritional support of cancer patients

Initially, total parenteral nutrition (TPN) was not used in cancer patients because of the fear of sepsis and the potential for stimulation of tumor growth. It was used first in cancer patients who had failed all attempts at enteral nutrition and in whom adequate anticancer therapy would have been otherwise impossible. TPN candidates today remain patients with responsive tumors who cannot tolerate the toxicity of cancer therapy because they are malnourished.

Inhibition of transforming growth factor alpha stimulation of human squamous cell carcinoma of the head and neck with anti-TGF-alpha antibodies and tyrphostin

BACKGROUND

Transforming growth factor alpha (TGF-alpha) and its receptor (EGF-R) may regulate normal and malignant epithelial cell growth by an autocrine mechanism. We investigated the role of TGF-alpha in regulating head and neck SCC tumor growth.

METHODS

TGF-alpha and EGF-R levels were measured in 7 SCC cell lines and 14 SCC biopsies by RIA, Scatchard, and Western analysis. TGF-alpha autocrine stimulation of DNA synthesis in SCC cell lines was assessed by incubation with TGF-alpha neutralizing antibodies and tyrphostin AG 1478, a selective and potent inhibitor of EGF-R kinase.

RESULTS

All SCC cell lines synthesized TGF-alpha and expressed elevated EGF-R levels compared to normal keratinocytes. Twelve of the 14 SCC biopsies contained TGF-alpha protein and 8 had specific EGF-R. Exogenous TGF-alpha or EGF significantly increased DNA synthesis in 4 of 5 SCC cell lines. TGF-alpha neutralizing antibodies or tyrphostin AG 1478 reduced DNA synthesis in the two SCC cell lines (FaDu and SCC9) tested.

CONCLUSIONS

These results indicate that SCC cell lines and tumors usually synthesize TGF-alpha, have elevated levels of EGF-R, and are mitogenically stimulated by a TGF-alpha autocrine system. Selective inhibition of the TGF-alpha system by EGF-R kinase inhibitors or TGF-alpha neutralizing antibodies may be useful strategies for treating SCC that overexpress TGF-alpha and its receptor.

Fulfilling the social contract between medical schools and the public

To gain a better understanding of the effects of medical schools related to transformations in medical practice, science, and public expectations, the Association of American Medical Colleges (AAMC) established the Advisory Panel on the Mission and Organization of Medical Schools (APMOMS) in 1994. Recognizing the privileges academic medicine enjoys as well as the power of and the strain on its special relationship with the American public, APMOMS formed the Working Group on Fulfilling the Social Contract. That group focused on the question: What are the roles and responsibilities involved in the social contract between medical schools and various interested communities and constituencies? This article reports the working group's findings. The group describes the historical and philosophical reasons supporting the concept of a social contract and asserts that medical schools have individual and collective social contracts with various subsets of the public, referred to as "stakeholders." Obligations derive implicitly from the generous public funding and other benefits medical school receive. Schools' primary obligation is to improve the nation's health. This obligation is carried out most directly by educating the next generation of physicians and biomedical scientists in a manner that instills appropriate professional attitudes, values, and skills. Group members identified 27 core stakeholders (e.g., government, patients, local residents, etc.) and outlined the expectations those stakeholders have of medical schools and the expectations medical schools have of those stakeholders. The group conducted a survey to test how leaders at medical schools responded to the notion of a social contract, to gather data on school leaders' perceptions of what groups they considered their schools' most important stakeholders, and to determine how likely it was that the schools' and the stakeholders expectations of each other were being met. Responses from 69 deans suggested that the survey provoked thinking about the broad issue of the social contract and stakeholders. Leaders on the same campuses disagreed about what groups were the most important stakeholders. Similarly, the responses revealed a lack of national consensus about the most important stakeholders, although certain groups were consistently included in the responses. The group concludes that medical school leaders should examine their assumptions and perspectives about their institutions' stakeholders and consider the interests of the stakeholders in activities such as strategic planning, policymaking, and program development.

Conservative treatment of rectal adenocarcinoma with endocavitary irradiation or wide local excision and postoperative irradiation

PURPOSE

To evaluate the role of endocavitary irradiation and wide local excision followed by irradiation in the treatment of early-stage rectal adenocarcinoma.

MATERIALS AND METHODS

Sixty-five patients with early-stage adenocarcinoma of the rectum were treated with endocavitary irradiation (n = 20) or wide local excision followed by external-beam irradiation (n = 45) between 1974 and 1994 at the University of Florida. All patients were monitored for a minimum of 2 years or until death.

RESULTS

The rates of local-regional control at 5 years were 80% after endocavitary irradiation and 86% after wide local excision and radiotherapy. The ultimate 5-year local-regional control rates were 85% and 92%, respectively. Multivariate analysis of local-regional control with sphincter preservation showed that tumor configuration (exophytic v ulcerative) significantly influenced this end point; local-regional control was decreased in patients with ulcerated cancers. Five-year cause-specific survival rates were 84% after endocavitary irradiation and 88% after wide local excision and radiotherapy. Multivariate analysis revealed that tumor configuration significantly influenced cause-specific survival; patients with ulcerated tumors had a worse prognosis.

CONCLUSION

Endocavitary irradiation is a highly effective treatment for properly selected patients with early-stage rectal adenocarcinoma. Patients with less favorable lesions that appear to be limited to the muscularis propria have a high chance of cure with sphincter preservation after wide local excision and external-beam irradiation.

Exogenously administered interleukin-10 decreases pulmonary neutrophil infiltration in a tumor necrosis factor-dependent murine model of acute visceral ischemia

INTRODUCTION

Visceral ischemia and reperfusion associated with thoracoabdominal aortic aneurysm (TAAA) repair results in lung injury, which appears to be mediated in part by proinflammatory cytokines. The purpose of this study was to determine the effect of exogenous administration of the antiinflammatory cytokine, recombinant human IL-10 (rhIL-10), on proinflammatory cytokine production (IL-6 and TNF alpha) and pulmonary neutrophil infiltration after acute visceral ischemia-reperfusion.

METHODS

Two hours before 25 minutes of supraceliac aortic occlusion, 80 C57BL/6 mice (20 to 22 g) received an intraperitoneal injection of rhIL-10 (0.2 microgram [n = 20], 2 micrograms [n = 20], 5 micrograms [n = 25], or 20 micrograms [n = 15]), and 16 mice received murine anti-IL-10 IgM 200 micrograms. Twenty-five additional mice underwent visceral ischemia-reperfusion without treatment (controls), and 16 mice underwent laparotomy without aortic occlusion (sham).

RESULTS

Pretreatment with exogenous rhIL-10 resulted in significant reductions in lung neutrophil infiltration with 0.2 microgram, 2 micrograms, and 5 micrograms per mouse of rhIL-10 compared with lung neutrophil levels in control mice that underwent acute visceral ischemia-reperfusion alone (p < 0.05). In addition, serum TNF alpha was detected in 50% of control mice and in 75% of mice that received murine anti-IL-10, but in none of the mice that received rhIL-10 (2 micrograms per mouse) or the mice that underwent sham operative procedures (p < 0.05 by chi 2 analysis).

CONCLUSION

Exogenous IL-10 limits pulmonary neutrophil recruitment and the appearance of TNF alpha in this model of visceral ischemia-reperfusion injury. Thus the use of exogenous IL-10 may offer a novel therapeutic approach to decrease the complications that are associated with TAAA repair.

Arginine-enhanced enteral nutrition augments the growth of a nitric oxide-producing tumor

BACKGROUND

Arginine-enhanced diets have been shown to be beneficial in tumor-bearing hosts, but no data exist regarding their effects in hosts bearing nitric oxide (NO)-producting tumors.

OBJECTIVE

To examine the effect of arginine supplementation on the growth of a NO-producing murine breast cancer cell line.

METHODS

EMT-6 cells were grown in various concentrations of arginine in the presence or absence of the inducible nitric oxide synthase (iNOS) inhibitor, aminoguanidine (1 mmol/L). Forty-eight hours later, nitrite accumulation and viable cell number were assessed. BALB/c mice were then pair-fed basal purified diets (n = 10), 4% casein diets (isonitrogenous control, n = 5), or 4% arginine-enhanced diets (n = 10). One week later, 10(5) EMT-6 cells were implanted subcutaneously into the dorsal flank. After tumor implantation, five mice fed basal purified diets and five mice fed arginine-enhanced diets also received aminoguanidine (100 mg/kg subcutaneously twice daily). Two weeks after tumor cell implantation, tumor size (mean diameter), animal weight, serum and tumor nitrite and nitrate levels were measured.

RESULTS

There was minimal nitrite accumulation in arginine-free media, while increasing the arginine concentration increased nitrite levels. Viable cell number did not increase in arginine-free media, but increased nearly twofold in 100 and 1000 mumol/L arginine. In 5000 and 10,000 mumol/L arginine, the difference in viable cell number was not statistically different than that seen in arginine-free media, whereas the addition of aminoguanidine blocked nitrite accumulation and increased viable cell number at these arginine concentrations. Arginine-enhanced diets stimulated tumor growth in vivo more than twofold over tumor growth in mice fed isonitrogenous control or basal purified enteral diets. Mice fed arginine-enhanced diets also had increased serum nitrite and nitrate levels over mice fed basal purified enteral diets, whereas tumors from mice fed arginine-enhanced diets had nitrite and nitrate levels similar to mice fed basal purified enteral diets. Aminoguanidine blocked the increase in serum nitrite and nitrate, but failed to block the increased tumor growth in mice receiving the arginine-supplemented diets.

CONCLUSIONS

Arginine concentration influences the growth of EMT-6 tumor cells in vitro and dietary arginine supplementation augments tumor growth in vivo. The mechanism of the growth modulation in vitro is NO-dependent whereas the enhanced tumor growth in vivo is NO-independent.

A matrix metalloproteinase inhibitor prevents processing of tumor necrosis factor alpha (TNF alpha) and abrogates endotoxin-induced lethality

Excessive tumor necrosis factor alpha (TNF alpha) production in response to Gram-negative bacteremia or endotoxemia can often lead to hypotension, shock, and increased mortality. Current approaches used to block the deleterious effects of exaggerated TNF alpha production rely on monoclonal antibodies or immunoadhesins that bind TNF alpha and thus prevent the interaction with its cellular receptors. This report examines whether a previously described inhibitor of matrix metalloproteinases, GM-6001, can inhibit TNF alpha processing and release and attenuate endotoxin-induced mortality. In human peripheral blood mononuclear cells stimulated in vitro with 1 microgram/mL endotoxin, GM-6001 at concentrations > 5 micrograms/mL blocked release of TNF alpha, but did not affect the release of either IL-1 beta or IL-6. GM-6001 also inhibited the release of soluble TNF receptor (p75) from peripheral blood mononuclear cells stimulated with endotoxin and/or TNF alpha. To confirm the role of secreted TNF alpha in endotoxic shock-induced mortality, C57BL/6 mice were challenged with either endotoxin alone (500 micrograms/mouse) or endotoxin (100 ng/mouse) plus D-galactosamine (8 mg/mouse). GM-6001 pretreatment (100 mg/kg) significantly attenuated the 90-minute plasma TNF alpha response in both models and improved survival in mice treated with low-dose endotoxin plus D-galactosamine. However, plasma IL-1 beta and IL-6 concentrations at 90 min after endotoxin treatment were unaffected by GM-6001 following lethal endotoxin challenge, confirming the in vivo specificity of this matrix metalloproteinase inhibitor for TNF alpha processing. These findings demonstrate that a novel inhibitor of matrix metalloproteinases can prevent the release of TNF alpha both in vitro and in vivo, and can abrogate the harmful sequelae of endotoxemic shock.

Proinflammatory cytokines, nutritional support, and the cachexia syndrome: interactions and therapeutic options

BACKGROUND

Protein calorie malnutrition remains endemic in hospitalized patients with both acute and chronic inflammation secondary to either cancer, chronic infectious processes, surgical injury, trauma, or burns. For the patients who cannot support themselves by enteral feeding, total parenteral nutrition remains an essential tool to minimize nitrogen losses and replete the depleted patient. However, in patients with active inflammation, nitrogen retention and lean tissue accretion are often impaired during total parenteral nutrition. Production of humoral factors, including proinflammatory cytokines, regulates many of the anabolic and catabolic processes that accompany inflammation.

METHODS

The investigators' experience with total parenteral nutrition and proinflammatory cytokines is reviewed.

RESULTS

Cytokines such as interleukin-1, tumor necrosis factor-alpha, and, in particular, interleukin-6 appear to play central roles in both the loss of skeletal muscle protein and the initiation of the acute phase response to inflammation, as well as in modulating the utilization of exogenously administered nutrients.

CONCLUSIONS

Although innovative second- and third-generation nutritional formulations for the acutely ill patient may represent one approach for improving the effectiveness of total parenteral nutrition, understanding the humoral response to inflammation and modifying cytokine actions pharmacologically may prove equally effective in improving the utility of exogenously administered nutrients. Future studies need to determine whether the effectiveness of exogenously administered nutrients in the patient with inflammation can be improved by efforts to modulate the proinflammatory cytokine response through cytokine inhibitors or antagonists.

Nitric oxide contributes to adriamycin's antitumor effect

Recently, several antitumor drugs have been shown to stimulate nitric oxide (NO) production.

PURPOSE

To determine if adriamycin induces NO production in breast cancer cells in vitro and whether NO contributes to adriamycin's antitumor effect in vivo.

METHODS

Murine breast cancer cells (EMT-6) were incubated with adriamycin (ADRIA, 0, 10, 100, 1000 microM) in the presence or absence of the NO synthase inhibitor aminoguanidine (AG, 1 mM). Twenty-four hours later nitrite accumulation (Greiss reagent) and cell viability (MTT assay) were assessed. Supernatants from adriamycin-stimulated cells were also analyzed at 6, 8, and 24 hr for TNF, IL-1, and IFN gamma (ELISA). For in vivo experiments, 10(5) EMT-6 cells were injected into the flank of BALB/c mice (n = 20) and 1 hr later mice received one of four treatments: (1) saline, (2) ADRIA (10 mg/kg ip), (3) AG (100 mg/kg sc BID), or (4) ADRIA (10 mg/kg ip) and AG (100 mg/kg sc BID). Two weeks later tumor size was measured and in situ tumor cell apoptosis was determined by fluorescent microscopy and flow cytometry.

RESULTS

Adriamycin was cytotoxic to EMT-6 cells with 100 microM resulting in nearly 100% killing (P < 0.01). Adriamycin also stimulated nitrite accumulation with 100 microM producing 6.5 +/- 0.26 microM nitrite (P < 0.001). AG blocked adriamycin-stimulated nitrite accumulation (P < 0.05), but did not inhibit cytotoxicity in vitro. In vivo, adriamycin inhibited tumor size by nearly 400% (P < 0.001), while AG attenuated adriamycin's effect on tumor growth (P < 0.05). There was no difference in the detection of apoptotic tumor cells between the adriamycin and adriamycin and AG groups as determined by immunohistochemistry and flow cytometry.

CONCLUSIONS

These findings suggest that adriamycin stimulated NO production in EMT-6 cells, but adriamycin's cytotoxicity in vitro was NO-independent. In vivo, adriamycin inhibited tumorigenesis partially via an NO-dependent, nonapoptotic mechanism.

Involvement of 26-kDa cell-associated TNF-alpha in experimental hepatitis and exacerbation of liver injury with a matrix metalloproteinase inhibitor

TNF-alpha is a pleiotropic cytokine that exists both as a 26-kDa cell-associated and a 17-kDa soluble form. Recently, a class of matrix metalloproteinase inhibitors has been identified that can prevent the processing by TNF convertase of 26-kDa TNF-alpha to its 17-kDa form and can reduce mortality from normally lethal doses of D-galactosamine plus LPS (D-GalN/LPS). Here we report that a matrix metalloproteinase inhibitor, GM-6001, improves survival but does not protect against liver injury from D-GalN/LPS-induced shock in the mouse. In Con A-induced hepatitis, GM-6001 actually exacerbates hepatocellular necrosis and apoptosis despite greater than 90% reduction in plasma TNF-alpha concentrations. Treatment with GM-6001 also has minimal effect on the concentration of membrane-associated TNF-alpha in the livers of animals with Con A induced hepatitis. In contrast, a TNF binding protein (TNF-bp), which neutralizes both membrane-associated and soluble TNF-alpha, prevents D-GalN/LPS- and Con A-induced hepatitis. Our studies suggest that cell-associated TNF-alpha plays a role in the hepatocellular necrosis and apoptosis that accompany D-GalN/LPS- or Con A-induced hepatitis, and that matrix metalloproteinase inhibitors are ineffective in preventing this hepatic injury.

Involvement of 26-kDa cell-associated TNF-alpha in experimental hepatitis and exacerbation of liver injury with a matrix metalloproteinase inhibitor

TNF-alpha is a pleiotropic cytokine that exists both as a 26-kDa cell-associated and a 17-kDa soluble form. Recently, a class of matrix metalloproteinase inhibitors has been identified that can prevent the processing by TNF convertase of 26-kDa TNF-alpha to its 17-kDa form and can reduce mortality from normally lethal doses of D-galactosamine plus LPS (D-GalN/LPS). Here we report that a matrix metalloproteinase inhibitor, GM-6001, improves survival but does not protect against liver injury from D-GalN/LPS-induced shock in the mouse. In Con A-induced hepatitis, GM-6001 actually exacerbates hepatocellular necrosis and apoptosis despite greater than 90% reduction in plasma TNF-alpha concentrations. Treatment with GM-6001 also has minimal effect on the concentration of membrane-associated TNF-alpha in the livers of animals with Con A induced hepatitis. In contrast, a TNF binding protein (TNF-bp), which neutralizes both membrane-associated and soluble TNF-alpha, prevents D-GalN/LPS- and Con A-induced hepatitis. Our studies suggest that cell-associated TNF-alpha plays a role in the hepatocellular necrosis and apoptosis that accompany D-GalN/LPS- or Con A-induced hepatitis, and that matrix metalloproteinase inhibitors are ineffective in preventing this hepatic injury.

Squamous cell carcinoma of the anal margin

Based on our experience and a review of the literature, we conclude that superficial, well- to moderately differentiated T1 cancers of the anal margin may be successfully treated with radiotherapy alone or local excision. Stage T2 lesions have a significant risk of inguinal lymph node metastases and should be treated with radiotherapy to the primary tumor in conjunction with elective inguinal lymph node irradiation. The best treatment for T3 and T4 lesions is radiotherapy to the primary lesion and regional nodes (inguinal and pelvic) combined with concomitant chemotherapy. Abdominoperineal resection (APR) should be reserved for patients who have fecal incontinence at presentation or locally recurrent disease after previous radiotherapy.

Increased L-arginine transport in a nitric oxide-producing metastatic colon cancer cell line

BACKGROUND

Little is known about amino acid transport in human neoplastic cells. We previously characterized L-arginine transport in the primary human colon cancer cell line, SW480, and found it is principally mediated by the sodium-independent system y+. In this study, we characterized L-arginine transport in the metastatic cell line, SW620, and compared it with that in the primary cell line, SW480.

METHODS

Transport of 3H-L-arginine in cell monolayers was analyzed in the presence and absence of sodium. Kinetic studies were performed over a range of L-arginine concentrations to determine transporter affinity (Km) and maximal transport velocity (Vmax). Transport was further characterized through blockade with known amino acids. In addition, the effect of cell age (i.e., time in culture) on arginine transport was examined at 2 and 9 days after seeding. Cellular proliferation was assessed by using the colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay.

RESULTS

L-Arginine uptake was primarily sodium independent in the SW620 cell line. Kinetic and amino acid-inhibition studies revealed a single high-affinity, sodium-independent L-arginine transporter (Vmax = 1286.3 +/- 158.3 pmol/mg protein/30 s; Km = 46.8 +/- 4.2 microM). Sodium-independent transport was blocked by system y+ substrates L-homoarginine, L-ornithine and L-lysine. Sodium-dependent uptake occurs through a single transporter with system BO,+ characteristics (Km = 16.15 +/- 2.1 microM; Vmax = 329.94 +/- 29.7 pmol/mg protein/30 s). Arginine transport increased with time in culture with day 2 cells transport velocity = 241.7 +/- 33.6 pmol/mg protein/30s, whereas day 9 cells transport velocity = 377 +/- 15.4 pmol/mg protein/30 s (p < 0.01). Cellular-proliferation studies revealed a doubling time of 3.2 days for SW620 and 5.4 days for SW480 (p < 0.05).

CONCLUSIONS

L-Arginine transport in these neoplastic cell lines occurs primarily through sodium-independent, high-affinity system y+. Vmax was increased 180% in the metastatic variant (SW620), suggesting upregulation of the Y+ transporter. The increased Y+ activity may be a mechanism to provide continuous substrate for tumor growth.

Preoperative treatment of patients with locally advanced unresectable rectal adenocarcinoma utilizing continuous chronobiologically shaped 5-fluorouracil infusion and radiation therapy

BACKGROUND

This study was designed to determine the efficacy and maximally tolerated dose of 5-fluorouracil when administered by chronobiologically shaped prolonged infusion in combination with radiation therapy in patients with both locally advanced and unresectable rectal carcinoma.

METHODS

Eighteen sequential patients determined clinically to have either locally advanced or unresectable rectal carcinoma were treated by 4500 centigray (cGy) or 5580 cGy, respectively, combined with continuous chronobiologically modulated 5-FU infusion starting at 250 mg/m2/day, with the dose escalating in each cohort of 5 patients if no Grade 3 or higher toxicity was observed in each cohort. Imaging studies were obtained prior to and after completion of treatment.

RESULTS

All 18 patients completed the full course of radiation therapy and all were subsequently resectable for potential cure. The maximum tolerated dose of 5-FU was 275/m2/day for 5 weeks. Seven patients had a sphincter-sparing procedure, and ten patients underwent an abdominoperineal resection, all with clear margins. Five complete pathologic responses (28%) were obtained. The average follow-up time was 12 months with a range of 6 to 37 months. With the exception of two patients, one of whom declined surgery and one of whom died of widespread disease, all of the patients have remained free of disease.

CONCLUSIONS

The combination of radiation therapy and continuous chronobiologically shaped 5-FU infusion at a dose of up to 275/m2/day is well tolerated and appears to be more effective in downsizing and possibly downstaging locally advanced and unresectable rectal carcinoma than radiation therapy alone. Longer follow-up will determine whether ultimate disease free and overall survival are improved by this method.

Preoperative treatment of patients with locally advanced unresectable rectal adenocarcinoma utilizing continuous chronobiologically shaped 5-fluorouracil infusion and radiation therapy

BACKGROUND

This study was designed to determine the efficacy and maximally tolerated dose of 5-fluorouracil when administered by chronobiologically shaped prolonged infusion in combination with radiation therapy in patients with both locally advanced and unresectable rectal carcinoma.

METHODS

Eighteen sequential patients determined clinically to have either locally advanced or unresectable rectal carcinoma were treated by 4500 centigray (cGy) or 5580 cGy, respectively, combined with continuous chronobiologically modulated 5-FU infusion starting at 250 mg/m2/day, with the dose escalating in each cohort of 5 patients if no Grade 3 or higher toxicity was observed in each cohort. Imaging studies were obtained prior to and after completion of treatment.

RESULTS

All 18 patients completed the full course of radiation therapy and all were subsequently resectable for potential cure. The maximum tolerated dose of 5-FU was 275/m2/day for 5 weeks. Seven patients had a sphincter-sparing procedure, and ten patients underwent an abdominoperineal resection, all with clear margins. Five complete pathologic responses (28%) were obtained. The average follow-up time was 12 months with a range of 6 to 37 months. With the exception of two patients, one of whom declined surgery and one of whom died of widespread disease, all of the patients have remained free of disease.

CONCLUSIONS

The combination of radiation therapy and continuous chronobiologically shaped 5-FU infusion at a dose of up to 275/m2/day is well tolerated and appears to be more effective in downsizing and possibly downstaging locally advanced and unresectable rectal carcinoma than radiation therapy alone. Longer follow-up will determine whether ultimate disease free and overall survival are improved by this method.