Tomio Ueno

Clinical application of porcine small intestinal submucosa in the management of infected or potentially contaminated abdominal defects

The repair of abdominal wall defects in potentially contaminated or grossly infected fields presents a difficult clinical problem. Polypropylene mesh is relatively contraindicated in these settings because of the potential for chronic infection. The alternatives to polypropylene include polyglactin mesh, which is not associated with chronic infection but is associated with a 100% recurrence of hernia. The ideal prosthetic for this patient group should be resistant to infection and ensure a low rate of hernia recurrence. We studied the use of small intestinal submucosa, which has been reported to be resistant to infection and incorporates into the fascia over 3 to 6 months, in 20 patients with ventral or inguinal hernias (18 ventral, 2 inguinal hernia) in the setting of bacterial contamination. The early postoperative complication rate was 50%. One patient with fasciitis had degradation of the small intestinal submucosa and loss of the bioprosthesis within 7 days. Other early complications included seroma (n = 2), ileus (n = 1), and wound infection (n = 8). No patient experienced chronic infection. Mean follow up was 15.7 months and the rate of recurrence documented by CT or physical examination was 30%. We concluded the following: (1) small intestinal submucosa is an effective alternative bioprosthesis in the management of ventral/inguinal hernia when there is associated bacterial contamination; (2) human vs. pig immune response has not been seen in this patient population; (3) early graft failure due to overwhelming fascial infection was noted in one patient and may be a limitation of this technology in a minority of patients; and (4) early hernia recurrence is relatively low but long-term follow-up has not been completed.

Effect of Neoadjuvant Chemoradiation on Operative Mortality and Morbidity for Pancreaticoduodenectomy

BackgroundNeoadjuvant chemoradiotherapy (neo-CRT) is being used with increasing frequency for periampullary tumors, but how it alters the complication rate of pancreaticoduodenectomy (PD) is unclear.MethodsA retrospective analysis was conducted of 79 patients with periampullary malignancies who received 5-fluorouracil–based neo-CRT followed by PD.ResultsThere was no difference in mortality between PD after neo-CRT (3.8%) and conventional PD for either malignant (4.5%) or benign (2.2%) disease. Focusing only on patients with malignancy, the neo-CRT group had a significantly lower pancreatic leak rate than the conventional group (10% vs. 43%; P < .001). Intra-abdominal abscesses were less common in the neo-CRT group (8.8% vs. 21%; P = .019), and there was one (1.2%) amylase-rich abscess in neo-CRT group, compared with eight (12%) in the conventional group. In addition, two patients in the conventional group died of leak-associated sepsis, compared with none in the neo-CRT group. Multivariate analysis revealed that neoadjuvant chemoradiation (odds ratio, .15) was the most significant factor associated with a reduced risk of pancreatic leak.ConclusionsNeo-CRT does not increase the mortality or morbidity of PD. In contrast, neo-CRT was associated with a marked reduction in the incidence of pancreatic leak, as well as leak-associated morbidity and mortality.

Modulation of chemotherapy resistance in regional therapy: a novel therapeutic approach to advanced extremity melanoma using intra-arterial temozolomide in combination with systemic O6-benzylguanine.

This study investigated whether the therapeutic index of regional melanoma therapy using parenteral temozolomide could be improved by chemomodulation with O6-benzylguanine (O6BG), an inhibitor of the DNA repair enzyme O6-alkylguanine-DNA alkyltransferase (AGT). Using a nude rat s.c. human melanoma xenograft model of the extremity, tumors were analyzed for AGT level 2 to 3 hours after the i.p. injection of 3.5 to 70.0 mg/kg O6BG to inhibit AGT activity. Survival studies were conducted using animals that were treated with a 15-minute isolated limb infusion with 10% DMSO in PBS (control), temozolomide alone, or temozolomide in conjunction with single or multiple doses of i.p. O6BG. Tumor volume and toxicity level were monitored every other day. Administration of 3.5 mg/kg O6BG depleted tumor AGT activity by 93.5% (P < 0.01). Groups treated with regional temozolomide alone (350 mg/kg), systemic temozolomide with O6BG, or vehicle combined with O6BG showed no significant tumor responses compared with controls. Whereas use of regional temozolomide alone at a higher dose (750 mg/kg) showed some degree of tumor response, regional temozolomide given in conjunction with multiple dosages of O6BG showed a marked (P < 0.01) reduction in tumor growth with minimal toxicity. Our findings suggest that AGT modulation by the administration of O6BG in combination with temozolomide regional chemotherapy leads to a significant improvement in melanoma antitumor responses. Clinical trials using chemotherapy modulation may improve response rates in future regional infusion and perfusion drug trials. [Mol Cancer Ther 2006;5(3):732–8]

Optimizing a Novel Regional Chemotherapeutic Agent against Melanoma: Hyperthermia-Induced Enhancement of Temozolomide Cytotoxicity

Purpose: Previous preclinical studies have shown that regional temozolomide therapy via isolated limb infusion is more effective than melphalan, the current drug of choice for regional chemotherapy for advanced extremity melanoma. The aim of this study was to determine whether hyperthermia could further augment the efficacy of temozolomide, an alkylating agent, against melanoma and improve its therapeutic index in a rat model of isolated limb infusion. Experimental Design: Athymic rats bearing s.c. human melanoma xenografts (DM6) in their hind limbs were randomized to a 15-minute isolated limb infusion procedure with or without temozolomide at room temperature, normothermic (37.5°C), or hyperthermic (43°C) conditions. Results: The concomitant administration of hyperthermia during an infusion with temozolomide led to the greatest increase in tumor growth delay, decreased proliferative index, and increased cell death. Isolated limb infusion treatment with a low dose (350 mg/kg) of temozolomide was ineffective at producing tumor growth delay (P = 0.07). Similarly, temozolomide infusion under normothermia yielded minimal tumor growth delay (P = 0.08). In contrast, the combination of hyperthermia plus temozolomide treatment produced marked tumor growth delay of 10.4 days (P = 0.02) with minimal toxicity. The addition of heat to temozolomide treatment yielded the smallest proliferative index (P = 0.001), while markedly increasing the level of apoptosis 48 hours after isolated limb infusion. Conclusion: This study, the first to examine the interaction between hyperthermia and temozolomide, shows a strong, synergistic antitumor effect when hyperthermia is combined with temozolomide for regional treatment of melanoma confined to an extremity. The mechanism of this synergy seems to be through an augmentation, by hyperthermia, of the antiproliferative and proapoptotic effects of temozolomide.

The Role of Hyperthermia in Regional Alkylating Agent Chemotherapy

The role of hyperthermia during regional alkylating agent chemotherapy is controversial. The aim of this study was to determine the exact contribution of hyperthermia to tumor response during isolated limb infusion with l-phenylalanine mustard. Rats bearing rodent fibrosarcoma on the hindlimb underwent isolated limb infusion with saline, saline plus heat, l-phenylalanine mustard, l-phenylalanine mustard under conditions of normothermia, or l-phenylalanine mustard plus hyperthermia. Heat was administered locally using an in-line hot water circulation loop. Treatment with l-phenylalanine mustard at a concentration of 15 or 50 μg/mL was ineffective at producing tumor growth delay (P = 0.24 and 0.41, respectively). Furthermore, thermal enhancement of l-phenylalanine mustard activity was not seen at 15 μg/mL. However, administration of high-dose l-phenylalanine mustard, 50 μg/mL, with increasing amounts of heat yielded increasing tumor growth delay, increased regressions, and decreased proliferative index. Although l-phenylalanine mustard infusion under normothermia yielded a tumor growth delay of 7.1 days, combination l-phenylalanine mustard + hyperthermia treatment produced tumor growth delay of 27.0 days (P < 0.01; with two of five animals showing a complete response). Four hours after isolated limb infusion, 50.9% of cells in tumor treated with l-phenylalanine mustard + hyperthermia experienced apoptosis, whereas only 18.1, 16, and 4.4% of cells underwent apoptosis after treatment with l-phenylalanine mustard, saline + hyperthermia, or saline. The mean concentration of l-phenylalanine mustard within tumor relative to perfusate following isolated limb infusion was found to be similar among all groups at 0.023, 0.025, and 0.032 in animals undergoing isolated limb infusion with l-phenylalanine mustard, l-phenylalanine mustard + normothermia, and l-phenylalanine mustard + hyperthermia, respectively. These data indicate a synergistic cytotoxic effect of l-phenylalanine mustard + hyperthermia in isolated limb infusion, which is not attributable to enhanced tumor drug uptake.

Role of hyperthermia in regional alkylating agent chemotherapy

The role of hyperthermia during regional alkylating agent chemotherapy is controversial. The aim of this study was to determine the exact contribution of hyperthermia to tumor response during isolated limb infusion with l-phenylalanine mustard. Rats bearing rodent fibrosarcoma on the hindlimb underwent isolated limb infusion with saline, saline plus heat, l-phenylalanine mustard, l-phenylalanine mustard under conditions of normothermia, or l-phenylalanine mustard plus hyperthermia. Heat was administered locally using an in-line hot water circulation loop. Treatment with l-phenylalanine mustard at a concentration of 15 or 50 micrograms/mL was ineffective at producing tumor growth delay (P = 0.24 and 0.41, respectively). Furthermore, thermal enhancement of l-phenylalanine mustard activity was not seen at 15 micrograms/mL. However, administration of high-dose l-phenylalanine mustard, 50 micrograms/mL, with increasing amounts of heat yielded increasing tumor growth delay, increased regressions, and decreased proliferative index. Although l-phenylalanine mustard infusion under normothermia yielded a tumor growth delay of 7.1 days, combination l-phenylalanine mustard + hyperthermia treatment produced tumor growth delay of 27.0 days (P < 0.01; with two of five animals showing a complete response). Four hours after isolated limb infusion, 50.9% of cells in tumor treated with l-phenylalanine mustard + hyperthermia experienced apoptosis, whereas only 18.1, 16, and 4.4% of cells underwent apoptosis after treatment with l-phenylalanine mustard, saline + hyperthermia, or saline. The mean concentration of l-phenylalanine mustard within tumor relative to perfusate following isolated limb infusion was found to be similar among all groups at 0.023, 0.025, and 0.032 in animals undergoing isolated limb infusion with l-phenylalanine mustard, l-phenylalanine mustard + normothermia, and l-phenylalanine mustard + hyperthermia, respectively. These data indicate a synergistic cytotoxic effect of l-phenylalanine mustard + hyperthermia in isolated limb infusion, which is not attributable to enhanced tumor drug uptake.