Ten-year follow-up results of a randomized clinical trial comparing left thoracoabdominal and abdominal transhiatal approaches to total gastrectomy for adenocarcinoma of the oesophagogastric junction or gastric cardia.

BACKGROUND: The optimal surgical approach for treatment of oesophagogastric junction (OGJ) cancer is controversial. A randomized clinical trial (JCOG9502) comparing transhiatal (TH) and left thoracoabdominal (LTA) approaches was stopped after the first interim analysis owing to limited efficacy for LTA resections. Complete 10-year follow-up data are now available. METHODS: Patients with histologically proven adenocarcinoma of the OGJ or gastric cardia with oesophageal invasion of 3 cm or less were randomized to a TH or LTA approach. Both groups underwent total gastrectomy and splenectomy with D2 nodal dissection plus para-aortic lymphadenectomy above the left renal vein. For LTA, a thorough mediastinal lymphadenectomy below the left inferior pulmonary vein was also mandatory. The primary endpoint was overall survival. RESULTS: A total of 167 patients (82 TH, 85 LTA) were enrolled. The 10-year overall survival rate was 37 (95 per cent c.i. 26 to 47) per cent for the TH approach and 24 (15 to 34) per cent for the LTA technique (P = 0·060). The hazard ratio for death was 1·42 (0·98 to 2·05) for the LTA technique. Subgroup analysis based on the Siewert classification indicated non-significant survival advantages in favour of the TH approach. CONCLUSION: LTA resections should be avoided in the treatment of adenocarcinoma of the OGJ or gastric cardia. REGISTRATION NUMBER: NCT00149266 (https://www.clinicaltrials.gov).

Functional outcomes after extended surgery for gastric cancer.

BACKGROUND: Extended gastrectomy with para-aortic nodal dissection (PAND) or thorough dissection of mediastinal nodes using a left thoracoabdominal (LTA) approach is an alternative to D2 lymphadenectomy, with variable postoperative results. METHODS: Two randomized controlled trials have been conducted to compare D2 lymphadenectomy alone (263 patients) versus D2 lymphadenectomy plus PAND (260), and the abdominal-transhiatal (TH) approach (82) versus the LTA approach (85), in patients with gastric cancer. Prospectively registered secondary endpoints bodyweight, symptom scores and respiratory function were evaluated in the present study. RESULTS: Bodyweight was comparable after D2 and D2 plus PAND, but higher after TH than after LTA procedures at 1 and 3 years. At 1- and 3-year follow-up symptom scores were comparable between D2 and D2 plus PAND. A LTA approach resulted in significantly worse scores than a TH approach in terms of meal volume, return to work, incisional pain and dyspnoea up to 1 year. The decrease in vital capacity was significantly greater after LTA than TH procedures up to 6 months. CONCLUSION: Bodyweight and postoperative symptoms were not affected by adding PAND to a D2 procedure. A LTA approach aggravated weight loss, symptoms and respiratory functions compared with a TH approach.

[Large cell neuroendocrine carcinoma of the lung].

Large cell neuroendocrine carcinoma (LCNEC) is a neuroendocrine tumor comprising a subgroup of large cell carcinoma and is a type of lung cancer showing a neuroendocrine characteristic similar to that of small cell lung carcinoma In our institution, we started to diagnose LCNEC by immunostaining in 2002, and we herein report 9 patients diagnosed with LCNEC from January 2002 to May 2008. The average patient age was 74.9, male/female ratio was 8/1, and all 9 patients had a smoking history. Pathological stages IA/IB/IIB/IIIA comprised 4/1/2/2, respectively. Peripherally located and lobulated tumors were noted on preoperative computed tomography (CT), and moderate uptake of fluoro-2-deoxy-D-glucose (FDG), which balanced with the size, was recognized on positron emission tomography (PET). All 9 patients underwent surgery and 7 underwent radical surgery. Postoperative adjuvant chemotherapy was performed for 4 patients. Three showed recurrence, and 2 of these 3 died of the primary disease. The remaining 7 patients have survived to date. The possibility of LCNEC must be considered when peripherally located lung cancer with lobulation is noted on CT and shows moderate uptake of FDG for its size on PET, and multimodal treatment is needed if the diagnosis is determined postoperatively.

Effect of carbohydrates on the ability of bull sperm to bind to bovine oviduct epithelial cells.

In the present study, we investigated the effect of various carbohydrates on the ability of bovine spermatozoa to bind to the bovine oviduct epithelial cells (OECs). We also examined the fertilization competence and motility of spermatozoa that bind to OECs in the presence of carbohydrates. Frozen-thawed spermatozoa were incubated with OECs, with and without various carbohydrates. The sperms were then divided into two fractions: OEC-binding sperms (B-sperm) and non-OEC binding sperms (NB-sperm). The fertilization rate, ability to bind the zona pellucida, and membrane integrity of the spermatozoa as determined using a hypo-osmotic-swelling test (HOST) were lower in NB-sperm than in the unseparated spermatozoa (control). The motility of the B-sperm was maintained for a longer time than that of the control spermatozoa. The addition of N-acetyl-d-glucosamine (GlcNAc, 5 mm) to the sperm-OEC mixture increased the number of B-sperm. D-mannose (5 mm) and D-fucose (5 mm) had no effect on the number of B-sperm. The motility of B-sperm, which bound to OECs in the presence of GlcNAc, however, was not maintained. When either OECs or the spermatozoa were treated with GlcNAc prior to sperm-OEC co-incubation, only sperm-side treatment enhanced sperm-OEC binding, but B-sperm motility was not maintained. The motility of spermatozoa incubated with GlcNAc was lower than that of controls. These results indicate that GlcNAc enhances sperm binding to OECs, probably via sperm surface modification, but does not promote increased sperm survival.

Stage migration caused by D2 dissection with para-aortic lymphadenectomy for gastric cancer from the results of a prospective randomized controlled trial.

BACKGROUND: Extended lymphadenectomy (D2) provides accurate nodal staging of gastric cancer. The aim of this study was to clarify the degree of stage migration seen with D2 combined with para-aortic lymph node dissection for gastric cancer invading the subserosa, the serosa and adjacent structures (T2ss-4) in patients considered not to have distant metastases (M0). METHODS: Between July 1995 and April 2001, 523 patients were recruited and randomized in a prospective phase III trial comparing D2 with D2 and para-aortic nodal dissection for T2ss-4 gastric cancer without macroscopic para-aortic nodal metastases. Stage migration was evaluated by Japanese Gastric Cancer Association staging in 260 patients who underwent D2 with para-aortic dissection by analysing pathological information from the dissected lymph nodes. RESULTS: Node (N)-stage migration was observed in 1 per cent (1 of 82) of patients with N1 disease, 20 per cent (12 of 59) with N2, 43 per cent (10 of 23) with N3 and 8.8 per cent (23 of 260) of all patients. Final stage migration occurred in 9 per cent (5 of 58) of patients with stage IIIa, 19 per cent (8 of 42) with stage IIIb, 56 per cent (9 of 16) with stage IVa and 8.5 per cent (22 of 260) of all patients. Metastasis to N4 nodes was found in 4 per cent (four of 95) of tumours invading the subserosa and 17.4 per cent (19 of 109) of tumours penetrating the serosa. The overall incidence of N4 involvement was 8.8 per cent (23 of 260). CONCLUSION: Extended para-aortic lymphadenectomy for gastric cancer provides accurate nodal staging and results in stage migration, which may improve stage-specific survival regardless of overall survival benefit.

Evaluation of sentinel node identification with isosulfan blue in gastric cancer.

AIMS: The aim of this study was to clarify whether the metastasis of gastric cancer can be detected by identifying the sentinel lymph nodes (SNs) using only lymphatic dye. METHOD: The study was based on 101 patients clinically diagnosed with T1 and T2 gastric cancer. Isosulfan blue was intraoperatively injected within the submucosal layer around the lesion through an endoscope and blue stained nodes (BNs) were identified as SNs and harvested. Standard radical gastrectomy with D2 lymphadenectomy was performed on all patients and SNs and other nodes were evaluated. RESULTS: Out of 101 patients, 21 had lymph-node metastases. The accuracy of SN identification was 97.0% (98/101) and the metastasis detection rate was 85.7% (18/21). With improvement of the manoeuvre in the latter 84 cases, the detection rate was elevated up to 100.0% (18/18), as was the accuracy (84/84). CONCLUSION: The sentinel concept using lymphatic dye is applicable to gastric cancer, but the identification of SNs with lymphatic dye requires some practice. Furthermore, the issue of intraoperative metastasis detection remains to be resolved.

Risk factors for myocardial injury during off-pump coronary artery bypass grafting.

BACKGROUND: Although off-pump coronary artery bypass grafting (CABG) is now used worldwide for coronary revascularization, the pre- and intraoperative risk factors for myocardial injury associated with the surgical procedure remain to be elucidated. We performed a multivariate analysis to investigate factors that contribute to myocardial injury during off-pump CABG. METHODS: The study population consisted of 22 patients who underwent off-pump CABG without apparent intraoperative complications. Blood samples were obtained before surgery and at 3 and 12 hours after the last anastomosis and serum Troponin T (cTnT) levels were measured to assess myocardial injury. Patient characteristics and factors related to preoperative cardiac function and the intraoperative process were analyzed to determine their correlation with serum cTnT levels, and the Spearman's correlation coefficient (r(s)) was computed. RESULTS: Neither age, preoperative cardiac function, time required for anastomosis, the number of grafts, nor the total amount of bleeding were associated with serum cTnT levels. Serum cTnT at 3 and 12 hours after completed anastomosis correlated with the product of mean systolic blood pressure and mean heart rate (double product) during anastomosis. The r(s) values at 3 and 12 hours were 0.62 (P = .002) and 0.58 (P = .004), respectively. With respect to the serum cTnT level at 12 hours, creatinine clearance (Ccr) had a slight effect on the serum cTnT values. CONCLUSIONS: High blood pressure and an increased heart rate during anastomosis are unfavorable factors for off-pump CABG. However, strict control of the blood pressure and heart rate makes it possible to subject even patients at high-risk to off-pump CABG from the viewpoints of myocardial injury.

Identification of risk factors for the development of complications following extended and superextended lymphadenectomies for gastric cancer.

BACKGROUND: Extended lymphadenectomy for gastric carcinoma has been associated with high mortality and morbidity rates in several multicentre randomized trials. METHODS: Using data from 523 patients registered for a prospective randomized trial comparing extended (D2) and superextended (D3) lymphadenectomies, risk factors for overall complications and major surgical complications (anastomotic leakage, intra-abdominal abscess and pancreatic fistula) were identified by multivariate logistic regression analysis. RESULTS: Mortality and morbidity rates were 0.8 per cent (four of 523) and 24.5 per cent (128 of 523) respectively. Pancreatectomy (relative risk 5.62 (95 per cent confidence interval (c.i.) 1.94 to 16.27)) and prolonged operating time (relative risk 2.65 (95 per cent confidence interval 1.34 to 5.23)) were the most important risk factors for overall complications. A body mass index of 25 kg/m2 or above, pancreatectomy and age greater than 65 years were significant predictors of major surgical complications. CONCLUSION: Pancreatectomy should be reserved for patients with stage T4 disease. Age and obesity should be considered when planning surgery.

A phase I study of S-1 combined with weekly cisplatin for metastatic gastric cancer in an outpatient setting.

A dose-escalation study was conducted for patients with metastatic gastric cancer to determine the recommended dose of weekly intravenous (i.v.) cisplatin combined with a fixed dose of a new oral dihydropyrimidine dehydrogenase-inhibitory fluoropyrimidine, S-1, on an outpatient basis. Secondary endpoints were to define the toxicity profile and to determine tumour responses. S-1 was fixed at a dose of 70 mg/m(2)/day and was administered for 2 weeks followed by a 1-week rest. Three dose levels of cisplatin (10, 15 and 20 mg/m(2)) were studied. Cisplatin was infused over 30 min on days 1 and 8. 20 patients were enrolled. No dose-limiting toxicities (DLTs) were recorded during the administration of cisplatin up to 20 mg/m(2), except for grade 3 diarrhoea and stomatitis in one patient at dose level 3. No grade 4 adverse events occurred. However, grade 2 gastrointestinal adverse reactions, such as nausea and anorexia, were seen in 7 of 13 patients at dose level 3 within the first two treatment cycles. This was determined to be the maximum acceptable level that would not negate the advantages observed with use of an oral drug such as S-1. An objective tumour response was seen at all dose levels, and the overall response rate in the 18 patients evaluated was 61%. A higher response rate of 78% was observed in 9 patients who had received no prior chemotherapy. Oral S-1 with weekly cisplatin is a feasible and promising combination regimen that is appropriate for an outpatient setting. A randomised phase II study comparing this combination with S-1 alone in chemo-nai;ve patients is warranted.

Periodate-treated, non-anticoagulant heparin-carrying polystyrene (NAC-HCPS) affects angiogenesis and inhibits subcutaneous induced tumour growth and metastasis to the lung.

Periodate-treated, non-anticoagulant heparin-carrying polystyrene consists of about ten periodate-oxidized, alkaline-degraded low molecular weight-heparin chains linked to a polystyrene core and has a markedly lower anti-coagulant activity than heparin. In this study, we evaluated the effect of non-anticoagulant heparin-carrying polystyrene on tumour growth and metastasis. Non-anticoagulant heparin-carrying polystyrene has a higher activity to inhibit vascular endothelial growth factor-165-, fibroblast growth factor-2- or hepatocyte growth factor-induced human microvascular endothelial cell growth than heparin, ten periodate-oxidized-heparin and ten periodate-oxidized-low molecular weight-heparin, which is probably due to the heparin-clustering effect of non-anticoagulant heparin-carrying polystyrene. Non-anticoagulant heparin-carrying polystyrene inhibited human microvascular endothelial cell, B16 melanoma and Lewis lung cancer cell adhesion to Matrigel-coated plates. Non-anticoagulant heparin-carrying polystyrene also showed strong inhibitory activities in the tubular formation of endothelial cells on Matrigel and B16-melanoma and Lewis lung cancer cell invasion in a Matrigel-coated chamber assay. In vivo studies showed that growth of subcutaneous induced tumours and lung metastasis of B16-melanoma and Lewis lung cancer cells were more effectively inhibited by non-anticoagulant heparin-carrying polystyrene than ten periodate-oxidized-heparin and ten periodate-oxidized-low molecular weight-heparin. Furthermore, non-anticoagulant heparin-carrying polystyrene markedly reduced the number of CD34-positive vessels in subcutaneous Lewis lung cancer tumours, indicating a strong inhibition of angiogenesis. These results suggest that non-anticoagulant heparin-carrying polystyrene has an inhibitory activity on angiogenesis and tumour invasion and may be very useful in cancer therapy.

Tumor volume as an indicator of nodal status in advanced gastric carcinoma.

BACKGROUND: The significance of tumor volume as an indicator of lymph node metastasis in advanced gastric cancer remains to be clarified. MATERIALS AND METHODS: Tumor volume was measured from continuous tissue sections taken from 60 patients with advanced gastric cancer (34 males and 26 females, aged 35 to 81 years; average 57.3 years) using a computer generated surface rendering method. The tumor volume and conventional clinicopathological factors were then analyzed with respect to the prevalence of lymph node metastasis. RESULTS: Lymph node metastasis was detected in 26 patients (43%). Of 28 patients with a tumor > or = 2000 mm3, lymph node metastasis was observed in 17 patients (61%): n1, 12 patients; n2, 3 patients; n3, 2 patients. Of 32 patients with a tumor < 2000 mm3, lymph node metastasis was observed in 9 patients (28%): n1, 6 patients; n2, 3 patients. A significant difference was found in the prevalence of lymph node metastasis between the two groups (p = 0.011). Furthermore, only tumor volume was an independent variable associated with lymph node metastasis according to logistic regression analysis (p = 0.013, odds ratio: 0.253, 95% confidence interval: 0.086-0.747). CONCLUSION: Tumor volume appears to be an important indicator of lymph node metastasis in advanced gastric cancer. However, this factor cannot be used to introduce the option of limited lymphadenectomy for such patients.

Experimental evaluation of photocrosslinkable chitosan as a biologic adhesive with surgical applications.

BACKGROUND: In various surgical cases, effective tissue adhesives are required for both hemostasis (eg, intraoperative bleeding) and air sealing (eg, thoracic surgery). We have designed a chitosan molecule (Az-CH-LA) that can be photocrosslinked by ultraviolet (UV) light irradiation, thereby forming a hydrogel. The purpose of this work was to evaluate the effectiveness and safety of the photocrosslinkable chitosan hydrogel as an adhesive with surgical applications. METHODS: The sealing ability of the chitosan hydrogel, determined as a bursting pressure, was assessed with removed thoracic aorta, trachea, and lung of farm pigs and in a rabbit model. The carotid artery and lung of rabbits were punctured with a needle, and the chitosan hydrogel was applied to, respectively, stop the bleeding and the air leakage. In vivo chitosan degradability and biologic responses were histologically assessed in animal models. RESULTS: The bursting pressure of chitosan hydrogel (30 mg/mL) and fibrin glue, respectively, was 225 +/- 25 mm Hg (mean +/- SD) and 80 +/- 20 mm Hg in the thoracic aorta; 77 +/- 29 mm Hg and 48 +/- 21 mm Hg in the trachea; and in the lung, 51 +/- 11 mm Hg (chitosan hydrogel), 62 +/- 4 mm Hg (fibrin glue, rubbing method), and 12 +/- 2 mm Hg (fibrin glue, layer method). The sealing ability of the chitosan hydrogel was stronger than that of fibrin glue. All rabbits with a carotid artery (n = 8) or lung (n = 8) that was punctured with a needle and then sealed with chitosan hydrogel survived the 1-month observation period without any bleeding or air leakage from the puncture sites. Histologic examinations demonstrated that 30 days after application, a fraction of the chitosan hydrogel was phagocytosed by macrophages, had partially degraded, and had induced the formation of fibrous tissues around the hydrogel. CONCLUSIONS: A newly developed photocrosslinkable chitosan has demonstrated strong sealing ability and a great potential for use as an adhesive in surgical operations.

Heparin-carrying polystyrene (HCPS)-bound collagen substratum to immobilize heparin-binding growth factors and to enhance cellular growth.

Heparin-carrying polystyrene (HCPS), consisting of low molecular weight heparin chains linked to a synthetic polystyrene core, is able to attach to polymeric surfaces. In this study, HCPS has efficiently bound to collagen-coated micro-plates and collagen membranes thereby retaining the binding of heparin-binding growth factors, such as vascular endothelial growth factor (VEGF)(165) or fibroblast growth factor (FGF)-2. Both human skin fibroblast cells and human umbilical vein endothelial cells have shown a good adherence to both collagen- and HCPS-bound collagen substrata. The growth rate of the fibroblast cells on the HCPS-bound collagen substratum in the presence of low concentrations of FGF-2 is higher than on a collagen surface. The fibroblast cells grow at a significantly higher rate on the HCPS-bound collagen substratum retained with FGF-2. Similarly, the growth rate of the endothelial cells on the HCPS-bound collagen substrata in the presence of low concentrations of either FGF-2 or VEGF(165) is higher than on collagen. The endothelial cells also grow at a significantly higher rate on the HCPS-bound collagen substratum retained with either FGF-2 or VEGF(165). These results indicate that HCPS-bound collagen substrata with various bioactive heparin-binding molecules may provide novel biomaterials controlling cellular activities such as growth and differentiation.

Nanosecond, high-intensity pulsed laser ablation of myocardium tissue at the ultraviolet, visible, and near-infrared wavelengths: in-vitro study.

BACKGROUND AND OBJECTIVE: A large number of clinical trials of transmyocardial laser revascularization (TMLR) have been conducted to treat severe ischemic heart diseases. A variety of laser sources have been used or tested for this treatment, however, no comprehensive study has been performed to reveal the mechanism and the optimum laser irradiation condition for the myocardium tissue ablation. There have been reported limited experimental data of the high-intensity pulsed laser ablation of myocardium tissues. STUDY DESIGN/MATERIALS AND METHODS: A 1064-nm Q-switched Nd:YAG laser and its 2nd (532 nm), 3rd (355 nm), and 4th (266 nm) harmonics were used for ablation experiments. At each wavelength, 25 laser pulses irradiated the porcine myocardium tissue samples at a constant laser intensity (peak laser power divided by laser spot area) of approximately 2 GW/cm(2) and the ablation depths were measured. During ablation, laser-induced optical and acoustic emissions were measured to investigate the ablation mechanism at each laser wavelength. For the ablated tissues, histological observation was made with a polarization optical microscope. RESULTS: It was shown that the ablation efficiency did not directly depend on the linear absorption coefficient of the tissue; the ablation depth was maximized at 355 and 1064 nm, and minimized at 532 nm. Strong laser-induced optical and acoustic emissions were observed for the 266- and 1064-nm laser irradiations. The histology showed that thermal denaturation of the tissue near the ablation walls decreased with decreasing wavelength for 266, 355, and 532 nm, but it was limited for 1064 nm. CONCLUSION: At the laser intensity of approximately 2 GW/cm(2), ablation characteristics were drastically changed for the different laser wavelengths. The results indicated that for 266, 355, and 532 nm, the tissue removal was achieved mainly through a photothermal process, but for 266 nm the intense laser-induced plasma formation would result in a reduced laser energy coupling to the tissue. For 1064 nm, a photodisruption was most probable as a dominant tissue removal process. Because of the high ablation rate and limited thermal denaturation, the 355- and 1064-nm lasers could be potential laser sources for TMLR, although further investigation is needed to discuss the clinical issues.

Disaster and cardiac disease.

Evidence obtained over the past decade has revealed that cardiac events and sudden cardiac deaths do not occur randomly but are caused by daily activities and emotional stress. Important triggers may be stress on autonomic nervous tone and sympathetic activities. Such sympathetic activities are changed in a circadian manner with fluctuations in blood rheology and catecholamine secretion. The threshold of electrical instability, left ventricular dysfunction and coronary stenosis may become reduced through the acceleration of sympathetic tone due to emotional stress, thus causing malignant arrhythmia and plaque rupture. Recognition of this multifactorial pathophysiology provides a basis for understanding preventive strategies.

Endothelial function and peripheral vasomotion in the brachial artery in neurally mediated syncope.

BACKGROUND: Paradoxical peripheral vasodilation is one of the suspected mechanisms of neurally mediated syncope. Parasympathetic stimulation following sympathetic activation during orthostatic stress mainly contributes to this vasodilation. HYPOTHESIS: Since endothelial function modulates peripheral vascular tone, this study aimed to determine whether endothelial function and inappropriate peripheral vasomotion has a significant role in the pathogenesis of neurally mediated syncope. METHODS: To investigate whether endothelial function is augmented or whether abnormal peripheral vasomotion exits, flow-mediated dilation (FMD, endothelium-dependent vasodilation) and sublingual glyceryl trinitrate-induced dilation (0.3 mg, GTN-D, endothelium-independent vasodilation) were measured in the brachial artery in 16 patients with neurally mediated syncope, aged 33 +/- 10 years, by using high-resolution ultrasound. All patients underwent positive head-up tilt testing. These measures were compared with those in 16 control subjects matched with the patients by age, gender, and coronary risk factors. For FMD, percent diameter changes were obtained from baseline to hyperemic conditions (1 min after 5 min occlusion of the forearm artery). There were five smokers in both the patient and the control groups, but there was no structural heart disease in either group. RESULTS: Baseline brachial artery diameters were comparable (3.8 +/- 0.6 vs. 3.8 +/- 0.7 mm, NS). Flow-mediated dilation in patients with neurally mediated syncope had a normal value of 9.8 +/- 5.0% despite the inclusion of five smokers. Flow-mediated dilation and GTN-D in patients with neurally mediated syncope were significantly greater than those in controls (9.0 +/- 5.0 vs. 3.0 +/- 3.5%, p<0.05; 18.4 +/- 5.5 vs. 14.1 +/- 4.4%, p<0.05). CONCLUSIONS: Augmented endothelial function and/or abnormal peripheral vasomotion in peripheral arteries are important in patients with neurally mediated syncope in selected populations.

Modified irinotecan hydrochloride (CPT-11) administration schedule improves induction of delayed-onset diarrhea in rats.

PURPOSE: Clinically, diarrhea is the major dose-limiting toxicity of irinotecan hydrochloride (CPT-11). Using a rat model, we attempted to decrease the incidence of delayed-onset diarrhea by modifying the administration schedule of CPT-11, and studied the pharmacokinetics in this model in relation to the incidence of diarrhea. METHODS: CPT-11 (total dose, 240 mg/kg) was administered intravenously (i.v.) to rats according to various schedules, and the incidence of delayed-onset diarrhea was monitored. RESULTS: Administration of CPT-11 at a dose of 60 mg/kg once daily for four consecutive days induced severe diarrhea, while at 30 mg/kg twice daily at an interval of 9 h (daily dose 60 mg/kg) for four consecutive days alleviated the diarrheal symptoms, and at 30 or 40 mg/kg once daily for eight or six consecutive days, respectively. diarrhea was hardly induced. With the first schedule, mucosal impairment of the cecal epithelium was observed, including wall thickening, edema, decrease in crypt number and size, and formation of pseudomembrane-like substance, whereas these changes were less severe with the second schedule and were hardly observed with the other two schedules. The areas under the plasma and cecal tissue concentration-time curves (AUCpla and AUCcec), the maximum plasma concentrations (Cmax) and the biliary excretions of CPT-11 and its metabolites, 7-ethyl-10-hydroxycamptothecin (SN-38) and SN-38 glucuronide (SN-38G) in rats depended on the daily dose of CPT-11. Exceptionally, CPT-11 Cmax was significantly lower and SN-38 AUCcec was larger in the animals treated at 30 mg/kg twice daily than in those treated at 60 mg/kg once daily. CONCLUSION: These results suggested that the duration of exposure to both CPT-11 and SN-38 of the intestinal epithelium and CPT-11 plasma Cmax are closely related to the incidence and severity of CPT-11-induced delayed-onset diarrhea in rats.