Michiyuki Kanai

CD4+CD25+ regulatory T cells in patients with gastrointestinal malignancies: possible involvement of regulatory T cells in disease progression.

Active suppression by CD4+CD25+ regulatory T cells plays an important role in the down‐regulation of the response of T cells to foreign and self antigens. Experimental tumor models in mice revealed that regulatory T cells inhibit antitumor immune responses. The purpose of the current study was to demonstrate the possible involvement of CD4+CD25+ regulatory T cells in immune system impairment in patients with gastrointestinal malignancies.

Usefulness of FDG-positron emission tomography in diagnosing peritoneal recurrence of colorectal cancer

BACKGROUND Accurate detection of peritoneal recurrence in colorectal cancer remains a diagnostic challenge. We retrospectively examined sensitivity and accuracy of fluorine-18-2-fluoro-deoxy-D-glucose positron emission tomography (FDG-PET) in the diagnosis of peritoneal recurrence. METHODS FDG-PET and computed tomography (CT) were performed on 23 patients with colorectal cancer suspected of having a recurrence based on clinical symptoms, a tumor marker (CEA), and so forth. The final diagnosis was compared with the results of FDG-PET and CT. RESULTS Peritoneal recurrence was suspected in 6 patients with FDG-PET, and 5 of them were finally diagnosed as recurrences. The sensitivity of FDG-PET was 88% and its diagnostic accuracy was 78%, whereas those of CT were 38% and 44%, respectively. A lesion as small as 15 mm in diameter was diagnosed by FDG-PET. CONCLUSIONS FDG-PET is an effective method for diagnosing peritoneal recurrence of colorectal cancer. FDG-PET is expected to become more important for detecting peritoneal recurrence at an early stage.

Tuberculous Lymphadenitis as a Cause of Obstructive Jaundice : Report of a Case

Abstract.We report a rare case of obstructive jaundice caused by enlarged tuberculous lymph nodes compressing the common bile duct in the retropancreatic region, mimicking pancreatic cancer. A 32-year-old man was admitted to our hospital with a 1-month of history of jaundice. An abdominal computed tomography (CT) scan showed a tumor in the pancreatic head, but an endoscopic retrograde cholangiopancreatogram (ERCP) showed a normal pancreatic duct system. Positron emission tomography with 2-[fluorine-18]-fluoro-2-deoxy-d-glucose (FDG-PET) revealed a hot spot only in the pancreatic head. Under a presumptive diagnosis of malignancy, a laparotomy was performed and an intraoperative biopsy specimen revealed epithelioid granuloma with caseous necrosis, which led us to suspect tuberculous lymphadenitis. This diagnosis was confirmed by culture, and antituberculous therapy was commenced postoperatively. The patient has not suffered any further episodes of obstructive jaundice. This case report demonstrates that positive FDG-PET results should be interpreted carefully when diagnosing tumors of the pancreatic head.

Change in Mitochondrial Membrane Potential in Peripheral Blood Lymphocytes, Especially in Natural Killer Cells, Is a Possible Marker for Surgical Stress on the Immune System

There is accumulating evidence that surgical stresses cause impairment of systemic immune responses, which may promote susceptibility to infection as well as growth of remnant cancer cells in cancer patients. Although alterations in numbers, populations, and functions of lymphocytes have been extensively studied to assess modulation of the immune system, the precise mechanisms of immunosuppression caused by surgical stresses have not been identified, nor have methods been developed to estimate the magnitude of surgical stresses on the immune system. In the present study, to evaluate the effects of surgical procedures on the immune system, the mitochondrial membrane potential (ΔΨm) of peripheral blood lymphocytes (PBL) from 25 patients who underwent various types of operation was measured by flow cytometry using 3,3′-dihexiloxacarbocyanine iodide (DiOC6(3)) on the day before operation and on postoperative day (POD) 1, POD 3, and POD 7. The ΔΨm in PBL, especially in natural killer (NK) cell population, was reduced after major surgery. In particular, the reduction of ΨΔm in NK cells appeared to be proportional to the severity of the surgical procedures and reflected the impairment of cellular function. Interestingly, the ΔΨm in NK cells was also negatively correlated with the level of plasma noradrenaline after major surgery, suggesting that the reduction of ΔΨm in NK cells induced by surgical stresses may bemediated, at least in part, by the accompanying increase in plasma noradrenaline. Monitoring of ΔΨm in PBL after operation may be one of the useful markers for estimating the magnitude of surgical stresses on the immune system.

Preventive effect of a traditional herbal medicine, Hochu-ekki-to, on immunosuppression induced by surgical stress

PurposeTo examine the effect of preoperative administering of a Japanese traditional herbal medicine, Hochu-ekki-to (TJ-41), on immunosuppression induced by surgical stress in patients with gastrointestinal malignancies.MethodsTo monitor the immune functions, the mitochondrial membrane potential (MMP) and natural killer (NK) cell activity prior to and following operation were measured in peripheral blood lymphocytes (PBL) in patients with (n = 20) or without (n = 27) the preoperative administering of TJ-41 for 7 days. The plasma catecholamine and interleukin (IL)-6 levels were also analyzed prior to and following the operation.ResultsThe numbers of MMP-high CD56-positive cells (NK cells) and NK cell activities in the TJ-41-treated group were significantly higher than those in the control group (P = 0.026 and P = 0.037, respectively). An elevation of plasma noradrenaline and IL-6 following surgery was also inhibited by the preoperative administering of TJ-41 (P = 0.023 and P = 0.039, respectively). A positive correlation between MMP-high CD56-positive cell numbers and NK cell activity in PBL treated with carbonyl cyanide m-chlorophenyl hydrazone (CCCP) in vitro suggested that MMP measurement in CD56-positive cells can serve as a convenient alternative to evaluate the NK cell activity.ConclusionOur findings suggest that the preoperative administering of TJ-41 prevents surgical stress-induced immunosuppression by maintaining the NK cell activity and inhibiting the elevation of stress mediators.

n-Propyl gallate activates hypoxia-inducible factor 1 by modulating intracellular oxygen-sensing systems

HIF-1 (hypoxia-inducible factor 1) is a master regulator of cellular adaptive responses to hypoxia. The expression and transcriptional activity of the HIF-1alpha subunit is stringently controlled by intracellular oxygen tension through the action of prolyl and asparaginyl hydroxylases. In the present study we demonstrate that PG (n-propyl gallate) activates HIF-1 and expression of its downstream target genes under normoxic conditions in cultured cells and in mice. The stability and transcriptional activity of HIF-1alpha are increased by PG. PG treatment inhibits the interaction between HIF-1alpha and VHL (von Hippel-Lindau protein) and promotes the interaction between HIF-1alpha and p300, indicating that PG inhibits the activity of both prolyl and asparaginyl HIF-1alpha hydroxylases. We conclude that PG activates HIF-1 and enhances the resultant gene expression by directly affecting the intracellular oxygen sensing system in vitro and in vivo and that PG represents a lead compound for the development of a non-toxic activator of HIF-1.

Usefulness of 99mTc-sestamibi scintigraphy in suggesting the therapeutic effect of chemotherapy against gastric cancer.

Purpose: Imaging with 99mTc-sestamibi (99mTc-MIBI) has been used to assess 170-kDa P-glycoprotein (P-gp) expression and predict chemotherapy responses in several types of malignancy, such as breast and lung cancers. The purpose of this study was to evaluate the relationship between 99mTc-MIBI accumulation in tumors and sensitivity to chemotherapy in gastric cancer patients. Experimental Design: Thirty-six patients with advanced gastric cancer underwent 99mTc-MIBI scintigraphy before chemotherapy. Patients also underwent endoscopic biopsy, and the expression of P-gp or multidrug resistance-associated protein was analyzed by immunohistochemical staining. The relationship between the accumulation of 99mTc-MIBI in tumors and responses to chemotherapy with 5-fluorouracil/cis-diamminedichloroplatinum(II) or epirubicin was examined. Results: Higher accumulation of 9mTc-MIBI in tumors was observed in 25 and 23 of 36 gastric cancer patients at the early (30 min) and delayed (120 min) images, respectively. Accelerated accumulation of 99mTc-MIBI negatively correlates with increased expression of P-gp, but not of multidrug resistance-associated protein, as determined by immunohistochemistry in gastric cancer tissues. The response rate to 5-fluorouracil/cis-diamminedichloroplatinum(II) chemotherapy in patients with high 99mTc-MIBI accumulation (15.4%) was much lower than that in patients with low 99mTc-MIBI accumulation (54.5%). In contrast, patients with high 99mTc-MIBI accumulation show a higher response rate (41.7%) to chemotherapy with epirubicin, which is known to be a substrate of P-gp transporter. Conclusions:99mTc-MIBI scintigraphy is useful to suggest the responses to chemotherapy of patients with advanced gastric cancer.

Reducing environment protects sinusoidal lymphocytes isolated from normal human liver from apoptosis

BACKGROUND/AIMS We previously reported that the populations of lymphocytes and the expression of activated antigens in human sinusoidal mononuclear cells were different from those in peripheral blood mononuclear cells. Attempts to culture these cells for further study failed because they died rapidly under standard culture conditions in vitro after isolation from the liver. In this study, we evaluated the characteristics of cell death and the effects of various culture conditions on the viability of these cells. METHODS Sinusoidal mononuclear cells were isolated from University of Wisconsin solution that had been perfused through the portal veins of normal healthy human livers harvested for transplantation into living related recipients. RESULTS 70% of sinusoidal mononuclear cells cultured in vitro were nonviable within 48 h after isolation, while only 10% of peripheral blood mononuclear cells died under the same conditions. Sinusoidal mononuclear cells showed DNA ladder formation of DNA on electrophoresis and characteristic morphological pattern on electron microscopic examination that suggested they had died in an apoptotic manner. The addition of human liver extracts or 2-mercaptoethanol and reduced glutathione to the cultures rescued the sinusoidal mononuclear cells from apoptosis. Furthermore, diamide, a sulfhydryl group specific oxidant, negated the effect of the liver extract. CONCLUSION In comparison with peripheral blood mononuclear cells, human sinusoidal mononuclear cells were more subject to death by apoptosis ex vivo, which was reversed by exogenous agents producing reducing conditions. These results suggested that hepatic sinusoidal mononuclear cells might express a different sensitivity to redox environment than peripheral blood mononuclear cells.

CHANGES IN GLUCOSE TRANSPORTER 2 AND CARBOHYDRATE-METABOLIZING ENZYMES IN THE LIVER DURING COLD PRESERVATION AND WARM ISCHEMIA: The Possibility of Evaluating the Viability of the Liver Graft before Transplantation

In order to examine glucose metabolism in liver grafts during cold preservation (24 and 48 hr), warm ischemia (60 and 120 min), a combination of the two and reperfusion, the amount of protein and mRNA of glucose transporter 2 and the activities of enzymes in glycolysis (glucokinase, phosphofructokinase, pyruvatekinase), gluconeogenesis (glucose 6-phosphatase, fructose 1,6-bisphosphatase), and the pentose phosphate pathway (glucose 6-phosphate dehydrogenase) were measured. It appeared that glucose transport, the pentose phosphate pathway, and gluconeogenesis were maintained during cold preservation and warm ischemia. The activity of glucokinase significantly decreased from the control value of 1.33 +/- 0.23 IU/g protein to 0.70 +/- 0.17 (24 hr, P<0.05) and 0.57 +/- 0.12 (48 hr, P<0.01) only during cold preservation. However, the activity of phosphofructokinase significantly decreased from the control value of 4.37 +/- 0.06 IU/g protein to 2.67 +/- 0.15 (60 min, P<0.0001) and 1.53 +/- 0.06 (120 min, P<0.0001) only during warm ischemia. This indicates that glycolysis deteriorates during both cold preservation and warm ischemia and demonstrates further that the balance between glycolysis and gluconeogenesis shifts to gluconeogenesis. Even when cold preservation was combined with warm ischemia, the activity of glucokinase decreased only during cold preservation and the activity of phosphofructokinase decreased only during warm ischemia. Furthermore, these changes were time-dependent. It is suggested that they can be used as a clock to measure the durations of cold preservation and warm ischemia separately and that the magnitude of an ischemic injury to a liver and a liver grafts viability can be indirectly estimated before transplantation.

Intra-arterial infusion chemotherapy with 5-fluorouracil and cisplatin in advanced pancreatic cancer: a feasibility study.

Objective:Our aim was to examine the efficacy and tolerability of intra-arterial infusion chemotherapy with 5-fluorouracil (5-FU) and cisplatin in advanced pancreatic cancer. Methods:Sixteen patients with unresectable locally advanced or metastatic pancreatic cancer (12 Stage IVa and 4 Stage IVb with liver metastasis) were enrolled. The catheter for intra-arterial infusion was placed at the position to distribute chemotherapeutic drugs to both the pancreatic tumor and the liver. Continuous infusion of 5-FU (250 mg/m2 per day, 7 days) with intermittent bolus injection of cisplatin (5 mg/m2 per day, 5 days) was repeated twice via the catheter, followed by intermittent injection of 5-FU (375 or 750 mg/m2) or cisplatin (7.5 mg/m2) once a week. The survival of these patients was compared with that of the matched historical control patients treated with other modalities. Results:In 12 Stage IVa locally advanced patients, the response rate was 58.3% (7 partial response). The median survival time was 22.0 months, and the 1-, 2-, and 3-year survival rates were 83.3%, 41.7%, and 16.7%, respectively. The locally advanced patients treated with intra-arterial infusion chemotherapy showed significantly better survival than the control patients. In contrast, Stage IVb patients with liver metastasis showed no response to the treatment (response rate, 0%). Treatment was discontinued in 2 patients until recovery from hematologic or hepatic toxicity, but fatal adverse events were not observed. Conclusion:These results suggest that intra-arterial infusion chemotherapy with 5-FU and cisplatin is tolerable and feasible treatment to improve the prognosis in locally advanced pancreatic cancer patients without distant metastasis.