[Bacteria isolated from surgical infections and their susceptibilities to antimicrobial agents. Special references to bacteria isolated between April 1998 and March 1999]

The annual multicenter studies on isolated bacteria from infections in general surgery and their antimicrobial susceptibility have been conducted in Japan since July 1982. This paper describes the results obtained in fiscal 1998 (from April 1998 to March 1999). The number of cases investigated as objectives was 225 for one year. A total of 429 strains (121 strains from primary infections and 308 strains from postoperative infections) were isolated from 183 cases (81.3% of total cases). In primary infections, the isolation rates of anaerobes and Escherichia coli were higher than in postoperative infections, while in postoperative infections, those of Gram-positive aerobes and Pseudomonas aeruginosa were higher than in primary infections. On the whole, among Gram-positive aerobes, the isolation rate of Enterococcus faecalis was the highest, followed by Staphylococcus aureus with high frequency in isolation from postoperative infections. Among Gram-positive anaerobes, Peptostreptococcus spp. and Streptococcus spp. were predominantly isolated. Among Gram-negative aerobes, E. coli, P. aeruginosa, Klebsiella pneumoniae and Enterobacter cloacae were frequently isolated. Among Gram-negative anaerobes, Bacteroides fragilis group was the majority of isolates. In primary infections, the percentage of Gram-negative aerobes has gradually increased since fiscal 1995 or 1996 with these years as the turning point, while those of Gram-positive and Gram-negative anaerobes have gradually declined. In postoperative infections, the percentage of Gram-negative anaerobes has increased continuously since the mid-1980s. The percentage of MRSA among S. aureus rose to 89.7%, which was the highest level since the beginning of this study. The susceptibilities of B. fragilis, which did not show apparent changes, were recognized to have decreased against cephems in fiscal 1998. Among other bacteria in B. fragilis group, development of resistance to cephems has continued on a long-term basis since the mid-1980s. E. coli and K. pneuminiae have obviously not changed in susceptibilities, however, the susceptibilities of isolated strains in fiscal 1998 against high-generation cephems, oxacephems and monobactams have declined. We found neither vancomycin-resistant nor teicoplanin-resistant strains of S. aureus and Enterococcus spp.

Changes in serotonin dynamics in the gastrointestinal tract of colon-26 tumour-bearing mice: effects of cisplatin treatment

Severe nausea and vomiting are common side effects of anti-cancer chemotherapy. 5-HT3 receptor antagonists have been used for the treatment of these gastrointestinal symptoms. The purpose of this study was to examine whether specific changes in serotonin dynamics occurred in the gastrointestinal tract in mice in which Colon-26 adenocarcinoma cells were injected s.c., especially after treatment with cisplatin. The serotonin content of the small intestine of mice inoculated s.c. with Colon-26 adenocarcinoma increased significantly 2 weeks after the inoculation of the tumor cells; this was associated with an increase in tryptophan hydroxylase activity and the number of enterochromaffin cells as compared with control mice. Intravenous injection of cisplatin significantly reduced the serotonin content in the small intestine of Colon-26 tumour-bearing mice but not in control mice. The spontaneous release of serotonin from isolated intestine was not different between Colon-26 tumour-bearing and control mice; however, pretreatment of mice with cisplatin induced two fold increases in serotonin release from duodenum, jejunum and ileum in Colon-26 tumour-bearing mice but not in control mice. These results indicate that a region-specific increase in the number of enterochromaffin cells is observed in the intestine of Colon-26 tumour-bearing mice, associated with an increase in the serotonin content and tryptophan hydroxylase activity. Cisplatin treatment induced the release of serotonin from affected enterochromaffin cells in the gastrointestinal tract, which may be related to the occurrence of nausea in clinical use.

Extensive cell death in thymocytes in colon 26-induced cachectic mice

Extensive atrophy has been reported to occur in the thymus in a cancer-burden state but the mechanisms of this atrophy have not been fully elucidated. We investigated changes in the thymus in tumour-bearing mice inoculated with two subclones of the murine colon 26 adenocarcinoma cell line: clone 5 (non-cachectic) and clone 20 (cachectic). In clone 20 mice, body weights and thymocyte numbers decreased significantly compared with controls. Flow cytometric analysis of the thymocytes demonstrated that the frequency of single positive cells (CD4+ CD8- and CD4- CD8+) was significantly increased and that of double positive cells (CD4+ CD8+) was significantly decreased in clone 20 mice and, to a lesser extent, in clone 5 mice compared with controls. Serum levels of interleukin 6 and granulocyte-macrophage colony-stimulating factor (GM-CSF) were significantly elevated. These results suggested that thymocyte apoptosis was accelerated in the cancer-cachectic state, and increased GM-CSF might be partly responsible for thymic atrophy.

Bacterial lipopolysaccharide induces transforming growth factor beta and hepatocyte growth factor through toll-like receptor 2 in cultured human colon cancer cells

This study examined, in human cancer lines, the pattern of cytokine production stimulated by lipopolysaccharide (LPS), a major component of outer surface of gram-negative bacteria, and characterized the expression pattern of CD14, cell surface LPS receptor antigen, and toll-like receptors (TLRs), which appear to be key regulators of the innate immune response system. Two colon cancer cell lines (DLD and LoVo), a hepatocellular carcinoma cell line and a myelomonocytic cell line were incubated with LPS for 0-72 h, and transforming growth factor (TGF) beta1 and beta2, hepatocyte growth factor (HGF) and interleukins 6, 8 and 15 were assayed. The only changes induced by incubation with LPS were significant increases in TGFbeta1 production at 12 h, and in HGF production at 72 h, in LPS-stimulated DLD cells, and significant increases in TGFbeta2 production after 12 h and in HGF after 72 h in LoVo cells. Using reverse transcriptase-polymerase chain reaction analysis, expression of CD14 and TLR-2 mRNA was detected in DLD and LoVo cells, and expression of TLR-4 mRNA was detected in PLC/PRF/5 and KG-1 cells. These results suggest that LPS induces TGFbeta and HGF production mediated by CD14/TLR-2 in cultured human colon cancer cell lines.

Down-regulation of IL-18 receptor in cancer patients: its clinical significance

Interleukin-18 (IL-18) is a powerful inducer of interferon-gamma (IFN-gamma), a key immunoregulatory cytokine. Cellular immune responsiveness, as measured by IL-18-induced IFN-gamma production from peripheral blood mononuclear cells (PBMCs) in ELISA assay, was evaluated in 10 patients with advanced cancer and in 10 normal controls. Supernatant levels of IFN-gamma were detected at 2 hours after PBMCs culture and markedly increased thereafter in healthy volunteers. In contrast, IFN-gamma production in cancer patients was not detected during the culture period (0-72 hours). We also measured IL-18-stimulated IL-12 production in healthy volunteers and null response was observed in cancer-bearing patients. Next, we studied mRNA expressions of IL-18 receptor (IL-18R) and IFN-gamma in PBMCs in cancer patients and healthy volunteers by RT-PCR assay. Both mRNA levels of IL-18R and IFN-gamma were significantly decreased in cancer-bearing patients compared with normal controls. These results suggested that IL-18 responsiveness for IFN-gamma production in cancer-bearing patients was impaired. Using flow cytometric analysis, we studied T-cell subsets, CD3- CD56+ (NK cell), CD3+ CD45RO+ (memory T-cell), CD3+ CD95+ (Fas+ T-cell), CD3+ CD4+ (helper T-cell), CD3+ CD8+ (cytotoxic T-cell: CTL) and CD3+ V alpha24+ (NKT-cell), in cancer patients and normal controls. The NK and cytotoxic T-cells significantly decreased and NKT-cells had decreased tendency in cancer patients compared with normal controls. In contrast, memory T cells, Fas+ T-cells and helper T-cells were all significantly increased in cancer patients compared with normal controls. These results suggested that the underlying mechanism of impaired IL-18 responsiveness in PBMCs from cancer-bearing patients was, at least in part, ascribed to a drastic decrease of NK cells and CTL which constitutively and highly express IL-18R and also attributed to null production of IL-12 which up-regulates IL-18R.

Blood transfusion and postoperative plasma cytokine antagonist levels in colorectal cancer patients

BACKGROUND/AIMS

Postoperative cytokine antagonist response affects various factors. However, excessive stress responses are deleterious as increased plasma concentration of cytokine antagonists may induce an impaired immune system.

METHODOLOGY

We determined plasma levels of cortisol, IL-1ra, and sTNF-R55 in 20 patients who had undergone resection of colorectal carcinoma. Ten patients had a blood transfusion during the operation (invasive group), but 10 patients had received no blood transfusion (less invasive group). Plasma levels of cytokine antagonists were determined before operation (POD 0) and POD-1, -2 and -7.

RESULTS

Postoperative plasma cortisol and sTNF-R55 levels were significantly elevated on POD-1 in the invasive group. Plasma IL-1ra levels were significantly increased on POD-1 in both the invasive and less invasive groups.

CONCLUSIONS

The present study demonstrated that perioperative allogeneic blood transfusion can induce an excessive production of cortisol and sTNF-R55, and might be deleterious.

Successful resection of rectal carcinoma in an Evans' syndrome patient followed by predonisolone and high-dose immunoglobulin: report of a case

A 69-year-old woman was admitted to our hospital because of anal bleeding and fatigue. The patient was previously diagnosed as having Evans' syndrome on the basis of hematological examination and had been treated with predonisolone for 8 years. On admission, severe anemia and thrombocytopenia were noted. Colonoscopy and Barium enema studies demonstrated an irregular tumor with hemorrhagic ulceration in the rectum, which was histopathologically confirmed as an adenocarcinoma. After red blood cells and platelets were transfused, and the patient was treated with high-dose gammaglobulin, predonisolone, and camostat mesylate, the platelet count gradually increased and hemolysis was well controlled. The patient then underwent Hartmann's operation and splenectomy without any postoperative complications. Predonisolone and high-dose immunoglobulin therapy in a rectal cancer burdened patient with Evans' syndrome is considered useful in combination with surgical treatment. This is the first case report of rectal carcinoma resection in a patient with Evans' syndrome.

IL-18-induced expression of intercellular adhesion molecule-1 in human monocytes: involvement in IL-12 and IFN-gamma production in PBMC

IL-18 time- and concentration-dependently upregulated the expression of intercellular adhesion molecule-1 (ICAM-1) in a monocyte population in human PBMC as determined by FACS analysis while the expression of CD11a, CD18, CD29, CD44, and CD62L in monocytes and that of ICAM-1, CD11a, CD18, CD29, CD44, and CD62L in T cells was not influenced by IL-18. IL-18 in the same concentration range stimulated the production of IL-12, TNF-alpha, and IFN-gamma in culture of PBMC; however, IL-18-induced expression of ICAM-1 in monocytes was not inhibited by anti-IL-12, anti-TNF-alpha, or anti-IFN-gamma Ab, suggesting the independence of the upregulating effect of IL-18 on endogenous IL-12, TNF-alpha, and IFN-gamma production. IL-18 also induced the aggregation of PBMC, which was prevented by anti-ICAM-1 and anti-LFA-1 Abs. On the other hand, anti-ICAM-1 and anti-LFA-1 Abs inhibited IL-18-induced production of three cytokines, IL-12, IFN-gamma, and TNF-alpha, by 60 and 40%, respectively. These results strongly suggested that the IL-18-induced upregulation of ICAM-1 and the subsequent adhesive interaction through ICAM-1 on monocytes and LFA-1 on T/NK cells generate an additional stimulatory signaling as well as an efficient paracrine environment for the IL-18-initiated cytokine cascade.

Immunomodulation based on a two-way paradigm with deoxyspergualin alleviates graft-versus-host reaction in small-bowel transplantation in rats

In this study, we investigated whether or not deoxyspergualin used as donor pretreatment, with and without pretreatment using bone-marrow-cell injection, could alleviate graft-versus-host reaction (GVHR) following small-bowel transplantation in an unidirectional GVHR model with Lewis (LEW)-to-F1 rats. In addition, we studied the effect of deoxyspergualin plus bone-marrow-cell donor pre-operative treatment in combination with recipient postoperative treatment using deoxyspergualin. When the donor was pretreated with bone-marrow cells from recipient rats, the recipient died at 7.2+/-1.4 days, showing significantly shorter survival compared with the control group. Deoxyspergualin, when employed either alone as recipient post-treatment or as donor pretreatment, both with and without additional pretreatment with F1 recipient bone-marrow-cell injection, did not result in significant prolongation of recipient survival. The combination of donor pretreatment with deoxyspergualin plus F1 bone-marrow-cell injection followed by post-operative deoxyspergualin administration, however, resulted in significant prolongation in recipient survival compared with control (26.1+/-1.7 days). In addition, no severe cutaneous lesions on GVHR were seen throughout the observation period. This suggests that donor pretreatment with deoxyspergualin and recipient bone-marrow-cell injection combined with postoperative deoxyspergualin administration can lead to resistance to GVHR after parent-to-F1 small-bowel transplantation.

Graft-versus-host reaction in small-bowel transplantation and possibilities for its circumvention

To study graft-versus-host reaction (GVHR) in small-bowel transplantation and its underlying mechanisms and to find methods for circumventing GVHR, we used an unidirectional GVHR model in which F1 Lewis (LEW) x Wistar King A (WKA) hybrid rats received small-bowel transplants from either LEW or WKA parent rats. The survival time of F1 hybrid rats that received full-length small-bowel transplantation from LEW and WKA was 16.3+/-2.1 days and 18.2+/-3.4 days, respectively. When one-quarter of LEW small bowel was transplanted to an F1 hybrid recipient, the survival time was significantly longer at 44.0+/-23.4 days compared with rats that had received full-length LEW small-bowel transplantation. The survival time of F1 hybrid rats which received an injection of high-dose (5 x 10(8) cells) LEW or WKA spleen cells was 11.9+/-4.0 days and 13.1+/-3.6 days, respectively. However, when an injection containing a low dose (1 x 108 cells) of LEW spleen cells was used, survival was > 100 days, showing significance compared with the survival of rats receiving the higher dose LEW spleen-cell injection. Both small-bowel transplantation and spleen-cell injection were compared for the effective period of recipient resistance to donor cell or small-bowel transplantation as second challenge. When the F1 rats given a quarter LEW small-bowel transplant as first challenge were treated with a high-dose of spleen cells 30 days after transplantation, they survived for > 30 days without GVHR. F1 rats that were treated with a low-dose LEW spleen-cell injection, followed 30 days later by full LEW small-bowel transplantation, had a survival time of > 100 days. These results indicate that segmental small-bowel transplantation and spleen-cell injection as first challenge may facilitate the prevention of GVHR, resulting in resistance to subsequent immunological challenge.

Donor dendritic cells and recipient Kupffer cells in the induction of donor-specific immune hyporesponsiveness

The aim of this study was to investigate the ability of portovenously administered donor antigens to induce immune hyporesponsiveness. Lewis (LEW, RT-1l) rats received Brown Norway (BN, RT-1n) rat donor splenocytes, via either the portal vein (PV group) or the peripheral vein (IV group). The immune responses of LEW rats, treated with either donor BN or third party Wistar King A (WKA, RT-1k) splenocytes were established by the persistence of donor dendritic cells (DCs) in the host liver measured using fluorescence microscopy and flow cytometry and by the mixed lymphocyte reaction (MLR). The effect of intravenous gadolinium chloride (GDCl3) on the blockade of Kupffer cell function prior to portovenous administration of splenocytes was also assessed. The MLR response was strongly inhibited in a BN-restricted manner after portovenous administration of donor BN splenocytes, but not by venous nor by portovenous administration of WKA splenocytes. Immunosuppression was blocked by pretreatment with GDCl3. The percentage of donor DCs in hepatic non-parenchymal cells (NPCs) was significantly higher in the PV group compared with the IV group. Treatment with GDCl3 decreased the percentage of donor DCs. In addition, cytotoxic T lymphocyte antigen 4 (CTLA4/CD152), which may function as an immune attenuator, was strongly stained, and B7 was weakly stained in recipient liver in the PV group compared with the IV group. These results suggest that both donor DCs and recipient Kupffer cells (self DCs) are involved in the induction of immune hyporesponsiveness by donor cells. This occurs via portovenous administration, in which a signal of the CTLA4-B7 pathway played an important part in inhibiting the interaction of CD28 and its B7 ligands.

Analysis of the immune status in the recipients with long-term well-functioning kidneys allografts

The immune status of thirteen living and related kidney transplant recipients with stable allografts were examined. The immunological assays consisted of a mixed lymphocyte reaction (MLR), cell-mediated lympholysis (CML) assay, interleukin-2 (IL-2) production in mixed lymphocytes culture (MLC) and IL-2 receptor (IL-2 R) expression on MLC cells. The suppression rates of the monoclonal antibodies (mAbs) against IL-2 R were tested on MLRs. The stimulation indices (SI) of the MLR against both donor and third-party cells increased compared with those of pretransplantation. The MLC responder cells stimulated by donor cells produced detectable amounts of IL-2, these amounts were lower than those by third-party cells. The MLC cells against donor cells expressed IL-2 R alpha and beta chains to the same degree as those against third-party cells. Anti-IL-2 R mAbs equally inhibited the MLRs between recipient and donor or third-party cells. Cytotoxic T lymphocytes (CTL) against donor cells were not generated, even with the addition of recombinant IL-2 in any of recipients except one, while anti-donor CTL had been detected prior to transplantation and the CTL against third-party cells were induced in posttranspalnt CML assays. These results indicate that the clonal anergy phenomenon might mediate the specific CTL unresponsiveness observed in kidney transplant recipients and the anergy phenomenon might serve in the long-term acceptance of allograft.

The effects of stimulating protease-activated receptor-1 and -2 in A172 human glioblastoma

Human glioblastoma cell line A172 expressed protease-activated receptor-1 and -2 (PAR-1 and PAR-2). We investigated the effects of the stimulation of these receptors by receptor-activating agonist peptides on the Ca2+ signaling, protein kinase C translocation, cell morphology and cell proliferation in A172. Both PAR-1 agonist SFLLRN and PAR-2 agonist SLIGKV induced an increase in [Ca2+]i. The prior treatment of A172 with PAR-2 agonist SLIGKV did not influence the [Ca2+]i response to PAR-1 agonist SFLLRN or thrombin, however, the prior treatment with PAR-1 agonist SFLLRN or thrombin completely abolished the second response to PAR-2 agonist SLIGKV. Treatment with each agonist peptide produced thinner and fewer processes in A172. The PAR-2 agonist inhibited the proliferation of A172 significantly while PAR-1 agonist did not. PKC-alpha and gamma were translocated from cytosol to membrane with either PAR-1 or PAR-2 stimulation, however, L was specifically translocated with SFLLRN, and lambda with SLIGKV, respectively. These results indicated that PAR-1 and PAR-2 stimulation produced a similar [Ca2+]i response and morphological changes in A172 glioblastoma while the effects on the cell proliferation and activation of PKC isozymes were distinct, suggesting that different signal transduction pathways were activated by these receptors. The uni-directional cross desensitization implies a functional linkage between PAR-1 and PAR-2 receptors.

Serum interferon-gamma-inducing factor/IL-18 levels in primary biliary cirrhosis

Primary biliary cirrhosis is an autoimmune disease of the liver in which T helper 1 cytokines predominate over those of T helper 2 in the pathogenesis. Interleukin- 18 (IL-18), for which the gene was recently cloned, is a novel T helper 1 cytokine, which augments interferon-gamma production. We designed this study to clarify the role of IL-18 in primary biliary cirrhosis and to examine whether serum IL-18 level can be a prognostic indicator for the disease. Serum IL-18 levels were measured using an enzyme linked immuno sorbent assay with mouse monoclonal antibodies. Twenty-two healthy volunteers, 31 patients with primary biliary cirrhosis (Scheuer's stage I, 13; II, 10; and IV, 8), 20 patients with autoimmune hepatitis, 11 patients with virus-related liver cirrhosis and six patients with obstructive jaundice were enrolled. Significant differences of serum IL-18 levels were observed between patients with Scheuer's stage IV and those with stage I, or II, virus-related liver cirrhosis and obstructive jaundice (P < 0.05). The IL-18 levels in primary biliary cirrhosis increased according to the disease progression, and fell promptly after living-related liver transplantation. Moreover, serum IL-18 levels in primary biliary cirrhosis were correlated with serum bilirubin concentrations and the Risk scores of the Mayo Clinic prognostic model for the disease. The IL-18 levels observed in patients with autoimmune hepatitis were also elevated, and correlated with the activity of the disease. These results indicate that serum interleukin-18 levels reflect the severity of primary biliary cirrhosis, the activity of autoimmune hepatitis, and may be an additive prognostic indicator in primary biliary cirrhosis.

Autologous serum deprivation restored IL-1 receptor antagonist production by peripheral blood mononuclear cells in patients with gastric cancer

It has been established that cancer patients have immunosuppressive substances in their sera that depress cellular immunity. Although plasma exchanges have been attempted to remove these substances and to improve immunity to cancer, little is known about its mechanism from the viewpoint of cytokine pattern. The levels of the cytokines, tumour necrosis factor-alpha, interleukin 1beta, interleukin 6, interferon-gamma and interleukin-1 receptor antagonist (IL-1ra) by peripheral blood mononuclear cells (PBMC) were determined simultaneously by the whole-blood assay and the PBMC assay in 20 patients with gastric cancer and in 10 healthy volunteers. In both assays the cytokine levels were lower in patients with cancer compared with healthy controls, with the exception of IL-1ra. In the PBMC assay, the IL-1ra level in cancer patients was significantly higher than that in controls. No statistical correlation between the cytokine levels determined by the two assays was found. We suggest that autologous serum deprivation restored and enhanced IL-1ra production, and normalized the cytokine cascade in immune response, in patients with gastric cancer.

Calcineurin antagonists inhibit interferon-gamma production by downregulation of interleukin-18 in human mixed lymphocyte reactions

Tacrolimus (FK-506) and cyclosporin A (CsA) are calcineurin antagonists used widely as T-cell immunosuppressants; however, their relative efficacy on the production of interleukin-18 (IL-18) remains undefined. We have examined the effects of FK-506 and CsA on the cytokine generation of human peripheral blood mononuclear cells (PBMCs) in mixed lymphocyte reaction (MLR) with lipopolysaccharide (LPS). We studied the levels of interleukin-18 (IL-18), IL-12, IL-10, IL-6, IL-2 and interferon-gamma (IFN-gamma) in the supernatant in allo-MLR by ELISA assay. Supernatant levels of IFN-gamma, IL-2, IL-6, IL-10 and IL-12 were detected 12 h after MLR and markedly increased thereafter. In contrast, production of IL-18 was detected at 12 h, reached a near maximum level at 24 h and decreased at 72 h. These results suggested that IFN-gamma production depended on IL-18, IL-12 and IL-2 in the early phase of MLR and depended mainly on IL-12 and IL-2 in the late phase. Both calcineurin antagonists inhibit the generation of IL-18, which plays a large role in allogeneic cell interactions, in macrophages and they also promote an equivalent down-regulation of T helper 1 (Th1) and Th2 responses in a concentration-dependent manner. About 90% of IFN-gamma production induced by MLR was inhibited by an anti-IL-18 antibody, showing that IL-18 can trigger IFN-gamma production in MLR. These results suggest that dual signaling consisting of antigen-driven nuclear factor of activated T cells (NFAT) activation and LPS-mediated NF-kappaB activation is crucial for IL-18 production in macrophages, and that IL-18 can trigger IFN-gamma production in T-cells by MLR.

Biochemical modulation of 5-fluorouracil with a streptococcal preparation, OK-432, against murine colon-26 carcinoma

Conventional therapy for colorectal carcinoma using 5-fluorouracil (5-FU) has shown limited antitumor action. The purpose of our study was to investigate synergistic antitumor effects of the streptococcal preparation of OK-432 and 5-FU, and to elucidate the mechanisms of interaction between the 2 agents in mice. Biochemical modulation of OK-432 and 5-FU were determined in vivo against colon-26 carcinoma. The concentration of 5-FU and its metabolites, and the activity of thymidylate synthase and thymidine kinase, respectively, were measured using cytosolic extracts of the tumors. Combination treatment with OK-432 produced a significant increase in intratumor 5-FU and 5-FU in RNA (F-RNA) concentrations, increased the thymidylate synthetase inhibition rate, and decreased thymidine kinase activity, as compared with the results observed in the control mice. These additive antitumor effects are obtained by use of the 2 agents; the mechanism of action is considered to be the suppression of both the de novo and the salvage pathway for DNA synthesis, along with the suppression of RNA synthesis.

Randomized controlled trial of 5-fluorouracil (5-FU) infusion combined with 1-hexylcarbamoyl-5-fluorouracil (HCFU) oral administration and HCFU alone as postoperative adjuvant chemotherapy for colorectal cancer

BACKGROUND

Although surgical resectability is an important prognostic factor, recurrences are commonly noted in advanced colorectal cancer patients, even after apparently curative surgery. Because such recurrences cannot be cured, better adjuvant chemotherapies are urgently required.

PATIENTS AND METHODS

We studied the effect of postoperative chemotherapy using 1-hexylcarbamoyl-5-fluorouracil (HCFU) oral administration with or without 5-fluorouracil (5-FU) infusion for curatively resected Stage II and III colorectal cancer. This study was prospectively randomized and controlled and 303 (95.6%) of 316 patients were determined to be candidates for statistical assessment. Group A received oral HCFU, 300 mg daily for 52 weeks beginning 2 weeks after surgery. Group B also received 5-FU intravenous injection, 333 mg/m2 body surface area/24 hours continuously for 72 hours beginning on postoperative day 0 and 6.

RESULTS

There were no differences in overall 5-year survival or disease-free survival between Groups A and B. Group B had better 5-year disease-free survival (47.6%) than Group A (42.9%) (p = 0.062) and significantly prolonged interval from surgery to recurrence (p = 0.003) for patients with lymph node metastasis. In contrast, group B had significantly shortened 5-year disease-free survival (p = 0.010) and increased recurrence rate in patients without lymph node metastasis.

CONCLUSION

Inductive therapy with 5-FU in combination with oral HCFU is beneficial as adjuvant chemotherapy for advanced colorectal cancer with lymph node metastasis.

[Bacteria isolated from surgical infections and their susceptibilities to antimicrobial agents. Special references to bacteria isolated between April 1997 and March 1998]

The annual multicenter studies on isolated bacteria from infections in general surgery and their antimicrobial susceptibility have been conducted in 19 facilities in Japan since July 1982. This paper describes the results obtained during the period from April 1997 to March 1998. The number of cases investigated as objectives was 215 for one year. A total of 420 strains (170 strains from primary infections and 250 strains from postoperative infections) were isolated from 174 cases (80.9% of total cases). In primary infections, the isolation rate of anaerobic bacteria was higher than in postoperative infections, while in postoperative infections, those of aerobic Gram-positive bacteria and Pseudomonas aeruginosa were higher than in primary infections. Among aerobic Gram-positive bacteria, the isolation rate of Enterococcus faecalis was the highest, followed by Staphylococcus aureus, which was frequently isolated from postoperative infections. Among anaerobic Gram-positive bacteria, Peptostreptococcus spp. and Streptococcus spp. were commonly isolated from both types of infections. Among aerobic Gram-negative bacteria, Escherichia coli was most predominantly isolated from primary infections, followed by P. aeruginosa, Klebsiella pneumoniae in this order, and from postoperative infections, P. aeruginosa was most predominantly isolated, followed by E. coli and K. pneumoniae. Among anaerobic Gram-negative bacteria, Bacteroides fragilis group was the majority of isolates from both types of infections. We found neither vancomycin nor arbekacin resistant strains of S. aureus, and found no vancomycin resistant strains of Enterococcus spp. The susceptibility of P. aeruginosa against carbapenems did not decline in the year 1997, while resistance of B. fragilis group against cephems advanced increasingly.

Generalized peritonitis due to spontaneously perforated pyometra presenting as pneumoperitoneum: report of a case

We report a rare case of generalized peritonitis due to a ruptured pyometra in an 86-year-old woman, and also conduct a review of the previous Japanese literature. The patient presented with muscle guarding and rebound tenderness. Computed tomography (CT) disclosed a cystic mass in the peritoneal cavity, in which an air-fluid level was noted. Pneumoperitoneum around the uterus due to gas production of anaerobic bacteria was noted on a CT. At laparotomy, the uterus was markedly enlarged with a necrotic area on the uterine fundus, which was found to be perforated. A supravaginal hysterectomy and drainage were performed. We found only eight cases of a ruptured pyometra presenting as pneumoperitoneum in the Japanese literature between 1977 and 1999. The most common cause of pneumoperitoneum is a perforation of the gastrointestinal tract. However, other possible causes, as seen in our patient, should also be taken into consideration. Although it is rare, a perforated pyometra should therefore also be considered when elderly women present with acute abdominal pain.

Fas-mediated cytotoxicity by gammadelta T cells during acute rejection in xenotransplantation of spheroidal aggregate-cultured hepatocytes

Xenogeneic transplantation has recently become a subject of interest for the transplantation community due to the current organ shortage, which could be partially or even totally solved by the development of this strategy. However, xenogenetic rejection remains a formidable barrier preventing such use in a clinical setting. The spheroidal aggregate-cultured hepatocytes of WKA rats were injected into the spleen of C3H mice, and quantitative assessment of transplanted xenogeneic hepatocytes using 99mTc-GSA demonstrated that hepatocytes decreased dramatically 2 days after transplantation (day 2) and few viable hepatocytes in spheroids were detected on day 3. The NK activity significantly increased on day 1, and gammadelta receptor/FasL-expressing T cells appeared on day 2. These results suggested that xenogeneic cytotoxicity consisted of gammadelta T cells through the Fas/Fas ligand system, as well as non-T-cell-mediated cellular response, in the MHC-unrestricted pathway in this intrasplenically transplanted xenogeneic hepatocyte model.

Histamine is a potent inducer of IL-18 and IFN-gamma in human peripheral blood mononuclear cells

Histamine (10-7 to 10-4 M) concentration-dependently stimulated the production of IL-18 and IFN-gamma and inhibited the production of IL-2 and IL-10 in human PBMCs. Histamine in the same concentration range did not induce the production of IL-12 at all. The stimulatory or inhibitory effects of histamine on cytokine production were all antagonized by H2 receptor antagonists ranitidine and famotidine in a concentration-dependent manner, but not by H1 and H3 receptor antagonists. Selective H2 receptor agonists, 4-methylhistamine and dimaprit, mimicked the effects of histamine on five kinds of cytokine production. The EC50 values of histamine, 4-methylhistamine, and dimaprit for the production of IL-18 were 1.5, 1.0, and 3.8 microM, respectively. These findings indicated that histamine caused cytokine responses through the stimulation of H2 receptors. All effects of histamine on cytokine responses were also abolished by the presence of either anti-IL-18 Ab or IL-1beta-converting enzyme/caspase-1 inhibitor, indicating that the histamine action is dependent on mature IL-18 secretion and that IL-18 production is located upstream of the cytokine cascade activated by histamine. The addition of recombinant human IL-18 to the culture concentration-dependently stimulated IL-12 and IFN-gamma production and inhibited the IL-2 and IL-10 production. IFN-gamma production induced by IL-18 was inhibited by anti-IL-12 Ab, showing the marked contrast of the effect of histamine. Thus histamine is a very important modulator of Th1 cytokine production in PBMCs and is quite unique in triggering IL-18-initiating cytokine cascade without inducing IL-12 production.

[Surgical stress and CARS: involvement of T cell loss due to apoptosis]

The term compensatory anti-inflammatory response syndrome(CARS) is the cytokine antagonist cascade which down-regulates the inflammatory cascade that appeared to contribute to the onset of bacterial infection. CARS represents immunosuppression, in which state reduced numbers of T cells in blood were encountered. Here we have determined whether this T cell loss is a consequence of bacterial antigen-mediated activation-induced cell death(AICD). By flowcytometric analysis, less than 0.3% of freshly isolated T cells from healthy volunteers and patients with severe pneumonia were identified as apoptosis. However, during culture, the rate of apoptosis in peripheral blood T cells from patients was 3.0 + 0.9%, and increased further in the presence of anti-CD3(7.4 + 2.1%) and decreased when IL-2 was added(4.4 + 1.3%). In contrast, there were no changes observed in healthy volunteers on addition of anti-CD3. Further, anti-CD3 significantly increased susceptibility to apoptosis of CD45RO+ T cells, but not CD45RA+ T cells from patients. Collectively, these findings demonstrated that bacteria-reactive T cells were more susceptible to AICD, and AICD of CD45RO+ T cells, therefore, provides an explanation for the loss of bacteria-reactive T cells during CARS.